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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S. patent application Ser. No. 12/620,326, filed Nov. 17, 2009, now U.S. Pat. No. 8,090,479, which is a continuation application of U.S. patent application Ser. No. 10/547,867, filed Jul. 24, 2006, now U.S. Pat. No. 7,620,482, which is a national stage filing of International Application No. PCT/US2004/06888, filed Mar. 5, 2004, and claiming priority to U.S. Provisional Patent Application No. 60/451,628, filed Mar. 5, 2003, entitled “ELECTRICITY MARKET-ORIENTED DC-SEGMENTATION DESIGN AND OPTIMAL SCHEDULING FOR ELECTRICAL POWER TRANSMISSION”, naming Mohamed M. El-Gasseir and H. D. Kenneth Epp as the inventors. The contents of all of the above-listed applications are incorporated herein by reference in their entirety, and the benefit of the filing dates of the earlier filed applications are hereby claimed for all purposes that are legally served by such claim for the benefit of the filing date.
BACKGROUND OF THE INVENTION
[0002] An accelerated growth of inter-regional electrical power transmission trading activities has sharply increased the frequency of transmission congestion and associated price spikes, leading in some cases to significant rise in electricity retail prices, and the bankruptcy of major utilities and power marketing companies.
[0003] There are two ways for averting or mitigating this problem: (1) investing heavily to upgrade existing grids and to develop new transmission ties; and/or (2) increasing the available transfer capability (ATC). In addition to public opposition and the high costs of developing new transmission rights of way, the first approach has proved to be elusive.
[0004] The second approach requires much less capital investment and is environmentally much more benign. However, there are no currently used or proposed processes for allocating and scheduling transmission service while explicitly increasing ATC for wholesale electricity trade.
[0005] The present invention addresses a pressing need for a better way of utilizing existing transmission infrastructures.
BRIEF SUMMARY OF THE INVENTION
[0006] In the present invention, there is provided a novel method as described herein of segmenting a pre-existing multi-regional alternating current (ac) grid into an interconnected set of ac sectors to facilitate the institution and operation of efficient regional and inter-regional electricity power transmission by making use of (1) the controllability of power flow through direct current (dc) transmission gates between ac grid sectors, and (2) the ability to expand ATC by liberating latent transfer capabilities of existing transmission infrastructure and through economic scheduling of electricity counter-flows.
[0007] In one aspect of the present invention, there is provided an electrical power transmission system as described herein when segmented pursuant to the foregoing method.
[0008] In a further aspect of the present invention, there is provided a method as described herein of allocating the costs of such segmentation.
[0009] In yet another aspect of the present invention, there is provided a method as described herein of achieving optimal operation of a segmented ac grid through efficient inter-sector scheduling of regional and inter-regional electricity trade.
[0010] The system and methodology make use of dc interconnection technology to interconnect otherwise isolated ac sectors at design locations where a pre-existing ac grid is segmented. Decomposing large ac grids into dc-linked ac sectors leads to a significant number of benefits including:
[0011] (1) Facilitating efficient solutions for otherwise intractable seams issues that continue to hinder the development of efficient inter-regional electricity markets;
[0012] (2) Liberating latent transfer capabilities of existing transmission infrastructure by eliminating stability limits on line ratings and loop flows in the grid;
[0013] (3) Preventing the cascading of major grid disturbances and subsequent outages over several service regions; and,
[0014] (4) Reducing inter-sector congestion problems.
[0015] Cost allocation follows the causation principle by identifying and separating the investment needed to facilitate the development and operation of efficient markets from the costs of enhancing grid reliability at regional and inter-regional levels. This step allows the assignment of proper costs to the appropriate capital recovery mechanism.
[0016] Optimal operation of segmented grids is achieved through the implementation of a novel process referred to herein as the Inter-Market Transmission Access Optimization and Scheduling (IMTAOS) process. IMTAOS accomplishes optimal operation by:
[0017] (1) controlling inter-sector power flows; and,
[0018] (2) enabling intra- and inter-sector ATC expansion.
[0019] Complete control of inter-sector power flows is made possible by the dc-interconnection technology used to segment the pre-existing ac grid. ATC expansion, beyond the gains achieved through upgrades such as line conversions or generated from eliminating or reducing loop flows and stability limits , is realized through the economic scheduling of counter-flows. The schedules generated by IMTAOS ensure verifiable alignment of contract paths with the physical paths of power flows, thereby removing a major source of the difficulties that have plagued the development of efficient electricity markets to this day. The developed scheduling process also leads to another highly sought result; namely, market liquidity of transmission rights.
[0020] The foregoing and other features and advantages of the present invention will now be described with reference to the drawings listed below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a map representation of an example dc-segmented transmission network.
[0022] FIG. 2 is a map representation providing an overview of an example infrastructure for the network shown in FIG. 1 .
[0023] FIG. 3 is a map representation illustrating example loading of the network shown in FIG. 1 .
[0024] FIG. 4 is a flow chart of a process for optimal segmentation of an ac interconnection for market-design purposes only while meeting current reliability criteria and for determining the gross cost of such investment.
[0025] FIG. 5 is a flow chart of a process for identifying the configuration and costs of segmenting for market-design under both current and new (cascading outages) reliability criteria (including gross investment cost and the present value of cascading outage costs).
[0026] FIG. 6 is a flow chart of a process for determining the configuration and gross cost of segmenting for reliability purposes only under both current and new (cascading outages) reliability criteria.
[0027] FIG. 7 is a flow chart of a process for assessing the dynamic performance of the ac interconnection in the absence of segmentation to determine the present value of the costs of cascading outages without segmentation.
[0028] FIG. 8 is a flow chart of a process for identifying dynamically critical gates in a system segmented for market-design purposes only and to determine the costs of the critical gates and of associated avoided outages.
[0029] FIG. 9 is a flow chart of a process for calculating the cost of segmenting ac grids for market-design purposes net of a credit for partial mitigation of cascading outages.
[0030] FIG. 10 is a flow chart of a process for calculating the cost of segmenting ac networks for market-design and reliability enhancement purposes net of a credit for full mitigation of cascading outages.
[0031] FIG. 11 is a flow chart providing an overview of the day-ahead inter-sector scheduling process.
[0032] FIG. 12 is a flow chart of the day-ahead transmission routing optimization process.
[0033] FIG. 13 consisting of FIGS. 13A to 13D is a flow chart of an algorithm for testing the physical feasibility of gate scheduling and for gate congestion management.
[0034] FIG. 14 is a flow chart of an algorithm for identifying the least cost configuration.
[0035] FIG. 15 consisting of FIGS. 15A to 15C is a flow chart of an algorithm for pro rata curtailment.
[0036] FIG. 16 consisting of FIGS. 16A to 16C is a flow chart of an algorithm for performing least-cost adjustments of gate schedules to eliminate congestion.
[0037] FIG. 17 is a flow chart providing an overview of a normal hour-ahead inter-sector scheduling process.
[0038] FIG. 18 is a flow chart of a normal hour-ahead transmission routing optimization process.
[0039] FIG. 19 is a flow chart providing an overview of a real-time inter-sector scheduling process in a three-settlement system.
[0040] FIG. 20 is a flow chart of a real-time transmission routing optimization process in a three-settlement system.
[0041] FIG. 21 is a flow chart providing an overview of a real-time inter-sector scheduling process in a two-settlement system.
[0042] FIG. 22 is a flow chart of a real-time transmission routing optimization process in a two-settlement system.
DETAILED DESCRIPTION
I. Background
[0043] As indicated above, segmentation refers to decomposing an ac interconnection into several sectors such that power flows among the sectors will proceed only through a network of dc gates. An ac interconnection is a grid comprised of several substantially interconnected control areas each of which include one or more service territories sharing a distinct set of transmission and bulk-power trading tariffs (e.g., the three ac interconnections serving the 48 contiguous states of the U.S.).
[0044] A control area is a transmission system or systems and associated infrastructure(s), owned by one or more entities but governed by a single regime of cost of service tariff(s), market rules, and operation and control apparatus and management.
[0045] A sector is a portion of the ac interconnection grid identifiable by a system of dc gates that is capable of controlling all of the sector's real power exchanges (imports and exports) with the rest of the ac interconnection at all times of system operation.
[0046] A dc gate is a dc interconnection device linking two ac sectors such that its location and operation in tandem and in combination with similar devices appropriately located on a segmented grid would provide a mechanism for total control of the magnitudes and directions of inter-sector power flows. A gate may consist of: (1) one or more pairs of back-to-back (BTB) ac-to-dc and dc-to-ac converters on transmission ties linking two sectors, or (2) a set of ac-to-dc and dc-to-ac converters at the ends of converted ac ties between two sectors, and (3) a combination of (1) and (2). In addition to separating sectors by gates, segmentation may also involve establishing cuts in an ac interconnection where cost considerations do not justify investing in dc technology.
[0047] FIG. 1 represents a simplified example of an ac network that has been segmented along the boundaries of three Grid Operators (GOs): GO(A), GO(B), and GO(C), GO(A) has also been segmented within its own area into two ac sectors. The heavy dashed lines indicate the GO boundaries and the dotted line the intra-sector boundaries for GO(A).
[0048] The light straight lines depict ac transmission lines which could be of differing voltage levels, for example 60 kV to 500 kV. The circular dots depict ac substations, which in turn, although not shown in FIG. 1 , connect to various lower and higher voltage lines and to generators and loads. The square dots depict ac-dc stations including pairs of BTB converters and single ac-dc converters. The heavy dark line depicts a dc line between one of the GO(A) segmented areas and the GO(C) sector.
[0049] The four-sectors shown in FIG. 1 are asynchronous and have no ac interconnections of any type with each other including low voltage ac lines commonly used at distribution voltages for multiple load delivery points. Segmentation can be applied to ac networks ranging in size from a few thousand megawatts to very large ac grids such as the Western and Eastern Interconnections of North America which represent hundreds of gigawatts.
[0050] Flows between the asynchronous ac sectors are controlled entirely by the dc apparatus. The apparatus consists of the sets of dc links (i.e., dc converters and lines) between the sectors.
[0051] FIG. 2 depicts operating centers for each of the GOs and for the dc interconnections. Each of these centers could consist of a central control headquarters as well as subordinate reporting centers. Communication links are shown as thin broken dashed lines. The links are for voice communications, data exchanges, monitoring, and system control purposes. Each sector's ac transmission network would be controlled by its GO. Neighboring GOs may jointly operate shared dc stations and lines. Alternatively, an interconnection coordination center (ICC) may operate the dc apparatus. Inter-sector trade schedules will be developed and enforced by the ICC only.
[0052] Typically all the equipment that together represents the ac and dc lines and interconnections would have multiple owners who would be required to operate the equipment under the direction of the GOs and the ICC, and who would receive revenues from the users and beneficiaries of the networks.
[0053] FIG. 3 depicts a typical loading of the dc interconnection gates shown in FIGS. 1 and 2 . Total generation (excluding for simplicity purposes reserve margin requirements and losses) and loads are indicated for each sector, as well as the power flows and direction of flow at each dc interconnection point.
[0054] Note that the flows between ac sectors are entirely determined by the inter-sector dc flows. A change in the flow at any one dc interconnection point may be matched by an increase in generation in one ac sector and a decrease in generation in the ac sector on the other side of the dc gate. Alternatively, the generation in each of the sectors involved can remain constant and the change in flow at one dc interconnection point is compensated by an opposite change in the flows at one or more dc interconnection points between the same two ac sectors. The ability to change flows through dc interconnection points while holding generation and loads in each ac sector constant demonstrates the liquidity possible through the application of dc gates. Liquidity is further increased by allowing for changes in both generation and dc gate flows.
II. Segmentation Design to Facilitate Efficient Market Operation
[0055] Segmenting an ac interconnection to facilitate efficient market operation would proceed along the steps identified in the process outlined in FIGS. 4 through 10 . The process enables separating the costs incurred for market facilitation from the costs that could be allocated to reliability enhancement. Such separation is essential for proper capital allocation as well as transmission services pricing and rate setting applications, and hence for valuing and capturing reliability credit for investments aimed primarily at improving market-designs.
A. Market-Design Segmentation Under Current Reliability Criteria
[0056] Designing to enhance market functions and operation requires segmenting the ac interconnection of interest at every ac tie between all pairs of bulk-power market regulation territories governed by distinct market tariffs. Meeting this requirement leads to the decomposition of the interconnection into ac sectors whose boundaries would coincide with the boundaries of the prevailing market tariffs. Each ac sector would be then operated under a distinct set of internally consistent market rules prescribed by the applicable tariff. The boundaries defining any sector would have to coincide with the collective jurisdictional territories of the interconnection's GO members assigned to the sector. A GO is any entity in charge of operating one or more transmission networks, such as vertically integrated utilities, federal power marketing agencies, independent transmission companies, independent system operators, regional transmission organizations, and other transmission service providers. A sector could be limited to a portion of the service territory of a single GO, or it could be as large as a combination of the control areas of several GOs. Because dc interconnection technology enables total control over the magnitudes and directions of inter-sector power flows, a sector may consist of a combination of non-contiguous ac networks.
[0057] The design process starts in FIG. 4 by decomposing the existing configuration of the targeted ac interconnection 1 into a number of ac sectors using the desired tariff boundaries under the market-design of interest 2 and available segmentation tools 3 . Thus, all transmission ties between the defined sectors would be identified and BTB converters would be installed on most (if not all of) the ac ties between neighboring sectors at already established tariff boundaries. In some cases, economic circumstances may favor ac-to-dc line conversions. In other situations, segmentation may render certain ties, particularly the low-voltage types, uneconomic to maintain and may have to be opened during at least normal operation. The desired mix of BTB, line conversions and ac tie deactivations would have to be determined through a collaborative effort between stakeholders in the neighboring sectors subject to applicable technical, economic and regulatory criteria.
[0058] The resultant configuration is an initial Market-Design Segmented System (MDSS) 4 .
[0059] It is possible that one or more member service areas might experience reduced post-segmentation grid reliability performance due to internal (i.e., native) generation or transmission outages that would not be satisfactorily mitigated because of lack of synchronous ac support from neighboring systems. Therefore, the reliability performance of the MDSS may have to be evaluated by conducting intra-sector reliability studies 6 using currently applied reliability criteria 7 . The analytic methods and software tools for carrying out the reliability studies 6 (including load flow simulations and system stability assessments) are well developed and commonly used. [1] The results of the reliability performance assessment are contrasted with the current criteria 8 . If the MDSS intra-sector reliability performance were found inadequate, a limited investment in intra-sector ac upgrades would be warranted 9 . The costs of any incurred remedial ac upgrades may have to be paid for in full or partially by the ac interconnection members who fear degraded local service reliability after loss of synchronous ac support (since prior to segmentation they were in effect leaning on their neighboring ac systems without necessarily having in place contractual arrangements for such support). To the extent the intra-sector ac upgrades are not paid for by the primary beneficiaries in the affected sectors, the costs of the initial MDSS would have to be updated 5 . Alternatively, the costs of ac upgrades could be tracked and recovered separately as intra-sector reliability support charges. Although the ultimate allocation of the costs of intra-sector upgrades may have to be determined through negotiations, the algorithm laid out in FIG. 4 provides an essential piece of information: the shadow price of maintaining the equivalent of the pre-segmentation synchronous support commonly exchanged among interconnected ac networks. No meaningful negotiation could proceed without this type of information.
[0060] Once the MDSS performance is deemed adequate from a current reliability criteria perspective, an optimal MDSS is established 10 . The attained design does not take account of the value of reliability improvements beyond the requirements of current reliability criteria. The result is the Gross Cost of Optimal Segmentation for Market Design Purposes Only 11 .
B. Market-Design Segmentation Under Full Dynamic Security
[0061] Because only dc current is permitted to flow through dc gates, ac disturbances will be prevented from propagating between ac sectors. Of special interest here is the potential reduction of the frequency and severity of a very costly type of ac disturbances; namely, interconnection or grid-wide cascading outages triggered by a certain class of initiating events. Cascading outages could lead to significant loss of loads and generation, and possibly system collapse. Gates installed for market-design enhancement purposes will block outages from propagating between sectors. However, problems may persist within individual sectors. Moreover, gates are not 100 percent reliable (due to normal failures or potential acts of sabotage or vandalism). In other words, there will always be a residual risk of cascading outages. In the case of segmentation projects limited to market enhancement, such risk may not be negligible. Policy makers may opt to eliminate or substantially reduce the residual risks of cascading outages by developing and enforcing new planning and operating criteria that could lead to the use of dc gates and associated technology beyond the needs of purely market-design projects. These criteria are new because they would address reliability issues above and beyond current industry practices. Their nature and specifics are subject to policy decisions to be undertaken by governments and regulators in consultation with the power industry. The new criteria can be either a set of performance standards targeted at reducing or even substantially eliminating the incidence and severity of cascading outages, or an economic criterion (e.g., the requirement that the incremental cost of segmenting the grid would not exceed the incremental benefit of reducing the expected costs of residual cascading outages).
[0062] FIG. 5 shows how an optimal MDSS configured specifically and only for market-design purposes could be further developed to meet new (cascading outages) criteria. The process exhibited transforms a segmentation project designed to enhance market operations into a dynamically secure (i.e., sufficiently impervious to cascading outages) MDSS. It starts with a multi-pass assessment of the system dynamics of the segmented grid each time the grid is modified for better containment of cascading outages. In the first step of the multi-pass evaluation, the dynamic performance of the MDSS 10 is evaluated by conducting system dynamics studies 12 using a comprehensive set of perturbations 13 designed to test and evaluate the dynamic response of the interconnection.
[0063] A system perturbation is an event or a contingency capable of initiating cascading outages. An initiating event consists of the involuntary (unscheduled) removal from service of two or more elements of one or more of the following system component categories: (i) generating units, (ii) intra-sector transmission facilities (e.g., common towers, ties on common rights-of-ways, and circuit breakers), and (iii) inter-sector dc transmission equipment including dc gates and dc ties. The list of vulnerable elements must extend beyond the existing infrastructure to include all equipment additions, upgrades and retirements to be undertaken over the planning horizon of interest. Initiating events can be either normal contingencies or the result of acts of vandalism or sabotage. Normal initiating contingencies are caused by a combination of mechanical failures due to wear and tear or weather-related causes, and, or human (operator) errors. Acts of vandalism and sabotage could be of the limited (localized) variety or in the form of coordinated attacks on the grid, and may emanate from domestic or international sources. Whether normal or not, the list of system perturbations 13 must be comprehensive in that it should include all credible events that could initiate cascading outages. However, new planning and operating criteria 19 implemented to mitigate the impacts of residual cascading outages could very well dictate the scope of the selection of the initiating events 13 . Algorithms for identifying and ranking initiating events have been developed and can be modified to prepare the required data set 13 . [2]
[0064] In conducting the system dynamics studies 12 , the set of perturbations 13 is to be applied using Monte Carlo simulation techniques to mimic the random arrival of the initiating events in consistent (non-overlapping) queues. (Other less rigorous techniques could also be employed. [3] However, there is risk that using alternative methods may lead to excessive reliance on subjective expert opinion.) The duration and frequency of the simulated contingencies have to be based on the performance history of the elements involved and the expected changes in the configuration of the grid. Potential acts of vandalism and sabotage would have to be accounted for through vandalism and sabotage (security) simulation scenarios.
[0065] In addition to using Monte Carlo routines to simulate the arrival of initiating contingencies, the system dynamics studies 12 would involve the application of well-established software tools for conducting power flow simulations and stability analyses. [4] The primary results of the system dynamics studies 12 include detailed accounts of the performance of the segmented interconnection in face of the initiating events incurred during each simulation run. These accounts would specify the observed voltage and frequency excursions, the amounts, durations and circuit locations of load service interruptions, and the dropped generation associated with each initiating contingency.
[0066] Using projections 17 of future patterns of loads growth and distribution and of generation production over the adopted planning horizon, the information produced by the system dynamics studies 12 is processed for each simulation run into forecasts 14 of: (i) load service outages, and (ii) generation drops. In the case of load losses, using load growth and distribution projections by geographic location and class of service 17 , the results of the system dynamics studies 12 can be translated into service interruptions in megawatt-hours of dropped loads by customer class-of-service, time of day and the utility providing the power 14 . Generation drops information 12 can also be detailed into plant outage schedules, including shutdown and recovery requirements 14 with input from generation projections 17 .
[0067] Using customers' value-of-service (VOS) projections 17 , the loss-of-load impacts of cascading outages 14 are translated into expected present values of cascading outage costs 16 . VOS inputs can be obtained through consumer survey techniques complemented by historic costs of loss-of-service due to cascading outages. Present values of lost generation 16 can be computed by combining projections of disconnected generation 14 with value of generation (VOG) forecasts 17 . VOG data can be obtained from wholesale-price projections generated by production costing models and, or market-based forecasts.
[0068] The present value computations would be carried out over the required number of Monte Carlo simulations to produce expected value projections 16 of the worth of load and generation losses. The number of simulations needed depends on the method used to economize on computational efforts (e.g., importance sampling). [5] Equations (1) and (2) provide simplified expressions for calculating the present values of load and generation losses in 16 on the basis of information from 14 and 17 :
[0000]
PVCOCLL
=
1
R
∑
r
=
1
R
[
∑
t
=
1
T
(
∑
i
=
1
I
∑
c
=
1
C
COLL
i
,
c
,
t
·
VOS
c
,
t
(
1
+
DR
)
t
)
]
(
1
)
PVCOCLG
=
1
R
∑
r
=
1
R
[
∑
t
=
1
T
(
∑
i
=
1
I
∑
g
=
1
G
COLG
i
,
g
,
t
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VOG
g
,
t
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1
+
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]
(
2
)
Where:
[0000]
PVCOCLL=Present value of cascading outage costs of lost load, $
PVCOCLG=Present value of cascading outage costs of lost generation, $
R=Number of Monte Carlo simulation runs
r=Monte Carlo run index
T=Number of periods of simulated system operation
t=Time step (period) of system operation
DR=Discount rate per time−step t
I=Number of simulated initiation events
i=Initiating event index
C=Number of customer classes
c=Customer class index
G=Number of generating facilities exposed to cascading outages
g=Generating unit index
COLL i,c,t =Cascading outages load loss caused by event i among customers class c at time t
COLG i,g,t =Cascading outages lost generation inflected by event i on generator g at time t
VOG g,t =Value of generation from generator g at time t
VOS c,t =Value of service for customer class c at time t
[0086] Along with the load and generation losses associated with simulated residual cascading outages, expected values of system performance indices can be derived in 16 from load and generation data projections 17 , and load and generation loss accounts 14 . Even though the number and nature of the indices to be used for segmented networks are yet to be determined (most likely by policy makers and regulatory bodies), the concept has been used by the industry for all phases of the power generation and delivery cycle. It is important to note that the desired indices must be compatible with the adopted planning (new) criteria 19 for mitigating cascading outages.
[0087] In 16 , the present value results of the first round represent the costs of residual cascading outages that the optimal MDSS could not block. This information is passed as Step 59 of the part of the process dedicated to identifying the dynamically significant gates in the optimal MDSS configuration. (See FIG. 8 .)
[0088] In 18 the current level of segmentation is tested against the adopted new criteria 19 . Because the criteria 19 could be in the form of either a set of performance standards (thresholds) or an economic objective or both, the testing in 18 has be flexible. Specifically, depending on the preferred design policy, one or both of the following tests can be made in 18 : (i) ascertain whether the expected values of the performance indices in 16 meet the new criteria 19 , and (ii) determine whether the present value of the current incremental increase in grid segmentation costs exceeds the present value of the costs of reduced residual cascading outages from 16 . If the answer to the applicable test(s) is yes, a dynamically secure market-design segmented system has been attained 22 and no further segmentation would be needed. If the answer is no, the new criteria have been violated and additional segmentation 3 of FIG. 4 is required.
[0089] In 3 of FIG. 4 , the system is segmented further by adding one or more gates or undertaking other measures (such as the opening of ac ties for normal operation). This action leads to splitting of at least one sector into two or more sectors. The result is a modified MDSS 21 . The new design 21 is then subjected to its own round of system dynamics studies 12 as described earlier. The evaluation process is repeated using Monte Carlo simulation techniques to verify compliance with the new criteria. If the answer is again no, the grid is segmented further and the rest of the steps are performed. The process continues until compliance is affirmed. The final result at this point is a complete specification 22 of the configuration, capital and O&M costs, costs of the ultimate residual cascading outages (if any), and the performance of a market-enhancement design capable of meeting new (cascading outages) reliability criteria.
[0090] As in the case of segmenting for market-design purposes only ( FIG. 4 ), it is possible that one or more member service areas could experience reduced grid reliability performance because of intra-sector generation and, or transmission outages after additional segmentation is performed on the MDSS. Such situation can be dealt with in the same manner outlined in Section A ( FIG. 4 ). The process starts with an evaluation of the intra-sector reliability performance of the dynamically secure MDSS 22 by conducting the appropriate intra-sector reliability studies 6 using currently applied reliability criteria 7 . The studies 6 to be carried out include traditional load flow simulations and system stability assessments. The results of the assessment are then compared 8 with the current reliability criteria 7 . If intra-sector reliability performance were found inadequate, intra-sector ac upgrades would be introduced 9 . To the extent the ac upgrades are not paid for by the primary beneficiaries in the affected sectors, the costs of the dynamically secure MDSS would have to be updated 22 . Alternatively, the new costs could be tracked and recovered separately as intra-sector reliability support charges. Again, the ultimate allocation of the costs of intra-sector upgrades may have to be determined through negotiations. The algorithm laid out in FIG. 5 provides the means for estimating the shadow price of maintaining the equivalent of the pre-segmentation synchronous ac support commonly exchanged among interconnected ac networks.
[0091] The incremental adjustment and assessment of intra-sector reliability performance is repeated until the adequacy of system design is established at 8 . Once this is accomplished, intra-sector upgrading costs are then tallied into total estimates of the additional costs to be incurred 28 . The results 28 are then added to the costs of the dynamically secure MDSS 22 to provide a gross estimate 27 of the cost of segmenting an interconnection for market purposes as well as to secure the grid against most (if not all) cascading outage events while meeting current (local) planning and operating reliability criteria. Note that 27 also conveys (from 16 ) the present value of the costs associated with residual cascading outages determined by the last round of system dynamics studies.
C. Segmenting for Reliability Only
[0092] Investing in grid reliability differs from market enhancements with respect to: (i) how project costs are allocated, and (ii) the achievable level of economy of scale savings.
[0093] First, regarding cost allocation, unlike market-design enhancements, protecting the public from cascading outages is a “common good” service benefiting all transmission system members of the interconnection to be segmented, and therefore the costs of such reliability service can be arguably rate-based (i.e., incorporated into customer retail rates by regulatory decree) over the entire interconnection. In the case of market enhancement, project costs cannot be rate-based on an interconnection-wide basis since the benefits might be limited to a single GO, and in some cases to a few generators or even a single supplier. As most projects affect both reliability performance and market operations, the subject of sorting out and properly allocating the costs and benefits of transmission investments has been and still is an area of intense research and debate. The invention at hand addresses this issue directly and presents a novel and robust methodology for resolving this matter in relation to interconnection-wide segmentation of electricity grids. The principles underlying this methodology are also applicable to ac investments affecting both reliability and market performance including flexible ac transmission systems (FACTS) projects.
[0094] Second, reliability investments could involve different economy of scale. For example, segmenting an interconnection with multiple regulatory market jurisdictions to minimize cascading outages may require much fewer gates than partitioning it for market-design purposes only. Since the price of an installed gate for any segmentation investment is likely to be very sensitive to the sizes and number of gates to be acquired for the project as a whole, there is bound to be two perspectives on how much an installed gate should cost: (i) a reliability-based estimate, and (ii) a market-enhancement value. Therefore, any assessment of a credit for reducing or eliminating cascading outages in the form of an avoided investment-cost of dc gates (as a by-product of a market-design segmentation project) must be evaluated from a purely reliability investment perspective in addition to a market-based approach.
[0095] This part of the design process achieves two objectives: (i) it establishes the basis for estimating the costs of segmenting the ac grid to only eliminate or minimize the impacts of cascading outages, and (ii) it identifies the gates needed for minimizing or even eliminating cascading outages. The results of achieving the first objective can be translated into avoided-cost credits—from a strictly reliability investment perspective—as compensation for the contribution(s) of market-design segmentation schemes to dynamic performance improvement. Accomplishing the second objective will facilitate the identification of the dynamically significant market-design gates.
[0096] As detailed in FIG. 6 , the process for segmenting an ac interconnection to only enhance reliability performance is very much similar to the one developed for transforming a market-oriented segmentation project into a dynamically secure grid (i.e., FIG. 5 ). The only differences between the two are the starting points and the end products. In the case at hand, the process starts at 1 with the configuration and performance parameters of the existing grid of the ac interconnection of interest and ends with a segmented system that meets all current and new (dynamic performance) reliability criteria ( FIG. 6 ). In the case of FIG. 5 , the starting point is the MDSS and the end product is a dynamically secure market design.
[0097] Guided by the known history of the dynamic performance of the ac interconnection 15 , the existing ac grid 1 is decomposed into an initial system design 29 consisting of a number of asynchronous ac sectors by inserting BTB converters at strategic locations on certain ties, and possibly by converting some inter-sector ac ties and opening other ac ties for normal operation 3 .
[0098] The initial design 29 is then subjected to a multi-pass evaluation of its dynamic performance each time the grid is incrementally segmented until certain criteria for containing cascading outages are met. In the first step of the multi-pass assessment, the performance of the initial design 29 is evaluated by carrying out system dynamics studies 12 using a set of perturbations 13 representing all credible events that could initiate cascading outages. The perturbations used here differ only slightly from those applied to the MDSS in FIG. 5 in that the set of segmentation equipment (e.g., gates) failures and outage scenarios are not going to be the same. New planning and operating criteria 19 for mitigating the impacts of residual cascading outages could determine the scope of the initiating events 13 . Again, algorithms for identifying and ranking the initiating events have been developed and can be modified as needed for 13 . [6]
[0099] It is best to apply the perturbations 13 using Monte Carlo simulation techniques to mimic the random incidence of the initiating events in non-overlapping queues. The simulated contingencies have to be based on the performance history of the grid elements involved and the expected changes in the configuration of the interconnection. The incidence of potential acts of vandalism and sabotage would have to be represented through security simulation scenarios.
[0100] The system dynamics studies 12 would also involve the use of traditional tools for conducting power flow and stability analyses. [7] The primary results of 12 include detailed accounts of the dynamic performance of the segmented grid after the incidence of an initiating event during each simulation run. The accounts would specify all observed consequences of every simulated initiating contingency such as voltage and frequency excursions, the amounts, durations and circuit locations of load service interruptions, and disconnected generation events.
[0101] Using loads growth and distribution projections 17 and generation production forecasts over the assumed planning period, the results of the system dynamics studies 12 are processed for each Monte Carlo run into forecasts 14 of: (i) load service interruptions, and (ii) generation disconnects. Using load growth and distribution projections by location and class of service 17 , the results of the dynamics studies 12 can be transformed into service outages in megawatt-hours by customer class-of-service, time of day and the utility supplying the power 14 . With input from generation projections 17 , generators disconnection information from 12 can be translated into plant outage schedules 14 .
[0102] Using VOS projections 17 and the loss-of-load impacts of cascading outages 14 , the expected present values 16 of cascading outage costs are then calculated. VOS data can be obtained through customary consumer surveys complemented by historic data on the costs of unscheduled loss-of-service due to cascading outages. Present values of lost generation 16 can be derived by combining disconnected generation projections 14 with VOG forecasts 17 . VOG data can be obtained from long-term projections of wholesale prices generated by production costing models and, or market-based forecasts.
[0103] The expected value projections 16 of the worth of load and generation losses would be computed over the needed number of Monte Carlo simulations (determined by the method used to economize on computational efforts). Equations (1) and (2) provide simplified formulas for estimating the present values of load and generation losses in 16 on the basis of results from 14 and 17 .
[0104] Expected values of system performance indices can be calculated in 16 using load and generation projections 17 , and load and generation loss accounts 14 . The number and nature of the indices to be used for segmented networks would be determined, most likely, by policy makers and regulatory bodies. The industry has used performance indices for all phases of the power generation and delivery cycle. For segmentation purposes, the desired indices must be compatible with the adopted new criteria 19 .
[0105] In 18 , the current level of segmentation is tested against the new criteria 19 . Depending on the chosen design policy, one or both of the following tests can be used in 18 : (i) determine whether the expected values of the performance indices of 16 meet the applicable new criteria 19 , and (ii) establish whether the present value of the costs of the last incremental increase in grid segmentation exceeds the present value of the costs of reduced residual cascading outages from 16 . If the answer to either or both questions is yes, a dynamically secure design has been attained 38 and no further segmentation would be needed. If the answer is no, the new criteria have been violated and additional segmentation 3 is needed.
[0106] In 3 , the system is further segmented by adding one or more gates or implementing other measures (e.g., opening ac ties for normal operation). This leads to the bifurcation of at least one sector into two or more sectors and hence into the modified design 21 . The new design 21 is then subjected to its own round of system dynamics studies 12 and the assessment process is repeated using Monte Carlo simulation to determine compliance with the new criteria. If the answer is again no, the grid is segmented further and the testing repeated. The process continues until compliance is established. The outcome at this point is a complete specification 38 of the configuration, capital and O&M costs, costs of the ultimate residual cascading outages (if any), and the performance of a segmentation design capable of meeting new (cascading outages) reliability criteria.
[0107] The next steps in the design process are to assess the need for and the costs of implementing intra-sector upgrades to compensate for any loss of interconnection ac support due to grid segmentation. This is accomplished by first evaluating the intra-sector reliability performance of the dynamically secure design 38 by carrying out the appropriate intra-sector reliability studies 6 using currently applied reliability criteria 7 . The studies 6 to be conducted include traditional load flow and system stability analyses. The results of 6 are compared at 40 with the current reliability criteria 7 . If reliability performance were found inadequate, intra-sector ac upgrades would be implemented 9 . To the extent the ac upgrades are not paid for by the primary beneficiaries, the costs of the dynamically secure design in 38 would have to be updated. Otherwise, the new costs could be recorded and recovered separately as intra-sector reliability support charges. The allocation of the costs of intra-sector upgrades may have to be decided through negotiations. The algorithm of FIG. 6 provides the means for determining the shadow price of maintaining the equivalent of the pre-segmentation synchronous ac support commonly exchanged among interconnected ac networks.
[0108] The incremental enhancement and evaluation of intra-sector reliability performance is repeated until the adequacy of system design is ascertained at 40 . Once this is achieved, intra-sector upgrading costs are tallied into total estimates of the additional investment to be undertaken 28 . The results of 28 are then added to the costs of the dynamically secure design 38 to yield a gross cost, in 43 , of segmenting an interconnection to only secure the grid against most (if not all) cascading outage events while meeting current (local) planning and operating reliability criteria. Note that 43 also provides through 16 the final set of performance indices and the present value of residual outages for the reliability-design project.
[0000] D. Assessing the Dynamic Performance of the Ac Interconnection without Segmentation
[0109] Because dc gates installed for market-enhancement segmentation projects can block the propagation (cascading) of outages between sectors, such investments could be eligible for reliability credits. This type of benefit could be essential for rendering capital-intensive projects economically justifiable. Estimating a reliability credit for a market-oriented segmentation investment requires identifying the gates that would contribute to service reliability improvements as well as the customers' savings associated with the achievable reduction in cascading outage impacts. This in turn necessitates establishing a status quo benchmark for: (i) evaluating the dynamic performance of the segmented grid, and (ii) identifying the gates that would contribute to reducing grid exposure to inter-sector cascading outages. The required benchmark is structured as a baseline forecast of the dynamic performance of the grid in the absence of segmentation over an agreed upon planning horizon. The forecast would consist of a set of mutually consistent baseline projections of future cascading outages and associated costs for the unsegmented ac interconnection of interest.
[0110] Assessing the dynamic performance of the unsegmented grid begins at 1 in FIG. 7 . Here, the configuration of the generation and transmission systems, as well as future load growth and distribution patterns are specified at levels of detail that would enable conducting the necessary system dynamics studies over a multi-year planning horizon. The needed information includes among other things adopted (consensus) forecasts of customers' loads, and expected generation additions, upgrades and retirements, and planned transmission investments (excluding of course segmentation projects).
[0111] The dynamic performance of the unsegmented grid 1 is evaluated by conducting system dynamics studies 12 using a comprehensive set of perturbations 46 designed to test and evaluate the dynamic response of the ac interconnection. The perturbations to be used in this part of the design process differs from those to be applied in designing fully secure market-focused projects (i.e., 13 in FIG. 5 ) and reliability-focused segmentation investments (i.e., 13 in FIG. 6 ) in that the initiating events represented by the perturbations to be simulated 46 do not include failure modes for dc gates and related segmentation equipment. Other than this exception, the list of vulnerable grid elements and the associated candidate initiating events must extend beyond the existing infrastructure to account for facility additions, upgrades and retirements to be undertaken over the planning horizon of interest, and therefore it should match those of FIGS. 5 (at 13 ) and 6 (at 13 ). Algorithms for identifying and ranking initiating events are available. [8]
[0112] In conducting the system dynamics studies 12 , the set of perturbations 46 is to be applied using preferably Monte Carlo simulation methods to mimic the random arrival of the initiating events in consistent queues. The duration and frequency of the simulated contingencies have to be based on the performance history of the grid elements involved and the expected changes in the configuration of the generation and transmission systems comprising the ac interconnection. The incidence of vandalism and sabotage would have to be accounted for through vandalism and sabotage (security) simulation scenarios.
[0113] The system dynamics studies 12 would also involve the application of well-known software products for conducting power flow studies and stability analyses. [9] The main results of 12 include annual records of the performance of the unsegmented interconnection in response to the initiating events incurred during each simulation run. These records would specify the observed voltage and frequency excursions, the amounts, durations and circuit locations of lost loads, and the disconnected generation associated with each initiating contingency.
[0114] The data generated by the system dynamics studies 12 is processed into forecasts 14 of load and generation losses caused by cascading outages during each simulation run. The load-loss forecasts in 14 would combine load growth and distribution projections (by geographic locations and class of service) 17 with the results of the system dynamics studies 12 to specify the details of the projected impacts, including the megawatt-hours of dropped loads by customer class-of-service, time of day and the utility providing the power. Detailed generation-loss forecasts can also be assembled by combining generation projections from 17 with generation-outage results from 12 .
[0115] The loss-of-load and generation impacts of cascading outages in 14 are translated into an expected present value of the costs 48 to consumers of cascading outages in the absence of grid segmentation using VOS projections from 17 . The VOS data can be generated through scientific customer surveys, complemented if necessary by historic information on economic losses caused by unscheduled loss-of-service episodes. The present value of lost generation can also be computed and passed on to 48 in a similar manner by combining projections of generation losses with VOG forecasts from 14 and 17 , respectively. VOG data can be obtained from long-term wholesale energy prices generated by production costing models and, or market-based forecasts. Equations (1) and (2) provide simplified expressions for calculating the present values of load and generation losses in 48 on the basis of information from 14 and 17 .
E. Identifying Dynamically Critical Gates in a System Segmented for Market Design Only
[0116] The objectives of this part of the process are: (i) to identify those dc gates that could be deemed actual contributors to preventing or lessening the incidence and, or severity of cascading outages; (ii) to quantify the costs of acquiring, operating and maintaining the identified gates; and (iii) to assess the monetary value of avoided service interruptions and averted blackouts because of segmentation-induced reductions in the frequency, duration and severity of cascading outages.
[0117] Identifying the dynamically significant gates is an essential step for valuing and establishing a reliability benefit credit for market-driven segmentation projects. The multi-pass process of FIG. 8 starts with the configuration of the optimal MDSS in 10 . Using as a guide information about the locations of the gates for a reliability-focused segmentation of the interconnection 43 , a modified MDSS 21 is created by taking out one or more gates and, or by closing normally opened inter-sector ac tie(s) 49 .
[0118] The modified design is then subjected to system dynamics studies 12 . The information needed for the studies includes: (i) a set of system perturbations 46 designed to evaluate the dynamic response of the interconnection and the interconnection's ability to minimize the consequences of a wide range of disturbances; and (ii) sufficient specification of the grid whose dynamic performance is to be evaluated. The first need is to be met by adjusting the optimal MDSS information base 10 to accommodate all changes introduced at 49 . The perturbations 46 to be applied should be the same as the set used to evaluate the dynamic performance of the unsegmented version of the grid ( FIG. 7 ).
[0119] The results of the first-pass studies at 14 will provide a measure of the dynamic performance of the modified MDSS 21 in terms of amounts of loads dropped and generation disconnected because of incurred outages. These projections are derived by combining the information generated in 12 about load and generation outage events with forecasts 17 of future loads (by service area and customer classes) and facility-specific production expectations. The results 14 are then translated into forecasts 16 of the present value of the costs associated with residual (unblocked) cascading outages using VOS and VOG projections 17 . The method for calculating the present value estimates is the same as described for the case of the unsegmented system ( 14 , 16 and 17 in FIG. 5 , and Equations 1 and 2). Projections of dynamic performance indices can also be generated in 16 on the basis of load and generation outlooks 17 forecasts and simulated outage losses 14 .
[0120] In 55 , the modified system's dynamic performance is compared with the response of the unsegmented ac interconnection 48 to the same set of perturbations. The performance of the unsegmented grid 48 is obtained through the steps depicted in FIG. 7 . If 55 indicates superior performance of the modified system, one or both of the following actions is taken: (i) one or more gates are removed from the grid; and (ii) one or more opened ac ties are restored for normal operation 49 . The dynamic performance of the modified MDSS 21 is then evaluated again 12 using the set of perturbations 46 . Steps 14 , 16 and 55 are subsequently implemented to appraise the system's performance relative to the unsegmented (status quo) grid, and further adjustments are made by way of 49 if needed. The modification and evaluation of the segmented system is repeated until its performance is no better than that of the unsegmented grid. The incremental removal of gates and other segmentation measures and the subsequent assessment of the dynamics of the modified systems should reveal the significance of the contribution of the disabled market-design features in containing system-wide disturbances.
[0121] Making certain that the dynamic performance of the partially segmented grid is not superior to its unsegmented counterpart does not guarantee that it would not perform worse. Steps 56 and 57 are to ensure that the dynamic performances of the modified segmented system 21 and the unsegmented version of the grid 1 (in FIG. 7 ) are comparable. This is accomplished by adding incrementally a gate, opening an ac tie and, or introducing ac upgrades at the proper location(s). The modified MDSS is then tested and its dynamic response is evaluated against the performance of the unsegmented grid. If the response of the modified MDSS improves beyond that of the unsegmented grid, the inner loop 55 to 49 to 21 is performed. If comparable performance is not achieved, the outer loop 56 to 57 to 21 is executed. The purpose of the second loop is to ascertain that the dynamic performance of the modified segmented system would not be worse than in the absence of any level of segmentation. In both loops, the grid performance comparisons could be carried out using the outage-costs present value results and, or performance indices. Note that in cases where the number of gates is very large and gate costs are highly diverse, the use of rigorous non-linear optimization techniques might be necessary for identifying the least-cost set of dynamically critical gates. Such optimization techniques are well established. [10] The ultimate result of this part of the FIG. 8 design process is a fully specified, partially segmented system 58 whose dynamic performance would be comparable to the performance of the status quo (i.e., the unsegmented version of the grid over the planning time horizon of interest) 1 (in FIG. 7 ).
[0122] Contrasting the configurations of the partially segmented system of 58 and of the optimal MDSS 10 will reveal the identities and locations of the dynamically critical dc gates 60 . The combined present value of the costs of acquiring, operating and maintaining the identified gates is then established at two levels: a low estimate based on the costs of full segmentation of the grid and a high value based on an investment commitment limited to the subset of gates deemed important contributors to mitigating cascading outages. The difference between the two estimates should reflect the importance of the effects of economy of scale on the costs of dc gates. Needless to say, the smaller the set of dynamic gates is relative to the investment needed for market design purposes, the greater would be the effects of economy of scale on the difference between the two estimates. It should be noted that the low value is likely to be supported by consumer advocates who wish to minimize rate-basing any part of an investment targeted at facilitating bulk-power markets. The high estimate reflects the cost that would have been incurred by ratepayers in implementing the critical set of gates that has accomplished the observed reduction in the costs of cascading outages. Sponsors of segmentation for market enhancement purposes would be in favor of using the higher value as a reliability credit to be netted out of the cost of their investment. The value that will be ultimately used will probably be determined through negotiations.
[0123] Consumer advocates may view giving market-driven projects reliability credits valued at the full cost of implementing a set of dc gates as unwarranted subsidization of private sector investments. Such critics may demand that any credit for segmentation be limited to the expected values of avoided cascading outages. Therefore it is necessary to evaluate the contribution of MDSS-like projects to consumers' welfare in the form of economic losses that would have been incurred had cascading outages not been mitigated by grid segmentation. Such avoided costs are forecasted as the present value of the costs of outages without segmentation 48 minus the present value of the economic losses associated with the residual outages of the MDSS 10 . The present value of the economic losses resulting from the residual outages of the optimal MDSS are estimated in the first round of the system dynamic studies at 16 ( FIG. 5 ) and passed on to 60 by way of 59 ( FIGS. 5 and 8 ). All the information needed to assess the dynamic reliability costs and benefits of MDSS gates is assembled in 60 .
F. Deriving the Net Cost of Segmenting for Market Enhancement Only
[0124] FIG. 9 describes the last series of steps in the segmentation design process for market enhancement only. These steps are concerned with deriving the cost of segmenting an ac interconnection for market design purposes only net of the value of the benefit of a quantifiable level of protection of the interconnection from cascading outages. Quantifying and netting out rate-based reliability credits from the costs of such projects could be essential to rendering them economically viable.
[0125] The process for deriving the net cost of segmenting an ac grid for market-design purposes only starts at 43 and 60 in FIG. 9 (originally from FIGS. 6 and 8 , respectively). Information about the costs of the individual gates identified (through the algorithm in FIG. 9 ) as dynamically critical for averting or containing cascading outages 60 is processed into a present value of the total cost of implementing these gates 61 . Investors in market-design segmentation may wish to reappraise the costs of these gates upwards by stripping away the economy of scale savings that would accrue in increasing the size of the investment from the more limited set of the dynamically significant gates to the full set needed for the market enhancement design. (The rationale for this is that grid users, including ratepayers, would have to pay more per gate to acquire a smaller set of gates.) Which estimate will be sponsored in 61 depends on the aggressiveness of the investors and their expectations about ratepayers' willingness to support a rate-based reliability credit for their project.
[0126] The worth of the dynamically important gates is better reflected by the present value of avoided economic losses (PVAEL) as a consequence of reduced cascading outages 60 . To the extent PVAEL could be credibly estimated, it becomes a better measure of the avoided costs credit for market-design segmentation projects. Note that if the term economic losses were broadened to include all users of the grid, PVAEL would be equal to the sum of the present values of ratepayers' and generators' avoided outage costs. However, it should be emphasized that the dominant contributor to PVAEL is expected to be the economic worth of avoided outage-related losses for ratepayers. (This is because customer service interruption costs are one to three orders of magnitude higher than the prices normally commanded by generators.) Also, whereas the ratepayers' contribution to a reliability credit could be arranged through a retail-rates charge, the generators' share could be collected as a service fee by the responsible grid operator(s).
[0127] The estimation of PVAEL will involve handling considerable uncertainties associated with the accuracy of, primarily, the simulation of the frequency, duration, timing and geographic domain of cascading outages, and to a lesser extent, the VOS data used. However, scientific engineering methods for establishing verifiable techniques for producing acceptable estimates and for quantifying the associated uncertainties are available. [11] Moreover, it is expected that PVAEL values will be large enough to make up for the risk of over estimating the reliability credit as set out in this process.
[0128] In 62 , PVAEL (from 60 ) is juxtaposed against the present value of the costs of dynamically significant gates from a market-design perspective (PVCDGMP) 61 . If PVAEL is found to be the lesser of the two, it sets the value of the reliability benefits credit from a market-design perspective (RBCMDP) 62 . If PVAEL is the larger of the two, PVCDGMP could act as a cap on what users of the grid are willing to pay to avoid the consequences of cascading outages. Symbolically, the valuation of the cascading outages reduction credit from a market-design perspective could be determined as follows:
[0000] If PVAEL≦PVCDGMP then RBCMDP=PVAEL (3)
[0000] If PVAEL>PVCDGMP then RBCMDP=PVCDGMP (4)
[0129] The formulation expressed by (3) is defensible since one does not expect grid users to pay for a reliability credit greater than the value of potential avoided outage costs. However, sponsors of market-design segmentation may argue against capping the amount of deserved credit by the PVCDGMP estimate—as in the expressions given by (4)—because in their view the potential savings to be realized by users of the grid are better represented by the present value of the avoided economic losses. In addition to this uncertainty over how to estimate the credit, the costs of the gates may or may not reflect the economy of scale savings that larger projects bring with them. Considering these potential differences between grid users and segmentation developers, the design process will yield a reliability benefits credit 62 somewhere between the lower of and the higher of the present values of the avoided costs of potential outages 60 and of the total cost of implementing dynamically critical gates 61 . The value ultimately applied would have to be settled through negotiations and, or regulatory proceedings.
[0130] Regardless of the method used, any value assigned to the reliability benefit credit 62 would always represent a market-design perspective since the basis for all of the underlying estimates is a market-focused segmentation project. An estimate from a reliability-design perspective is therefore needed. This is accomplished by upward adjustment of the costs of implementing the critical gates for market-enhancement purposes 60 to account for the diseconomy of scale associated with using fewer gates to segment an interconnection for reliability purposes only 43 (originally from FIG. 6 ). The resultant present value 64 of the total cost of the dynamically critical gates from a reliability-design perspective (PVCDGRP) is then juxtaposed against the present value of the avoided economic losses 60 to develop a reliability benefits credit from a reliability design perspective 65 . The estimation of the cascading outages reduction credit from a reliability-design perspective (RBCRDP) could be conducted in accordance to:
[0000] If PVAEL≦PVCDGRP then RBCRDP=PVAEL (5)
[0000] If PVAEL>PVCDGRP then RBCRDP=PVCDGRP (6)
[0131] The condition represented in (5) is defensible for the same reasons discussed above for the market-design perspective case. And again, sponsors of market-design segmentation may oppose capping the value of the credit by the PVCDGRP estimate—as specified in (6)—by advocating that the present value of avoided economic losses are more representative of the worth of the reliability benefits of their project. Additionally, PVCDGRP may reflect the economy of scale savings associated with meeting new cascading outages criteria or it might exclude them (by limiting the estimation to the smaller set of the dynamically significant gates matching those identified in the market-design segmentation case). Therefore, the value of the credit from a reliability-design perspective 65 will fall somewhere between the lower of and the higher of the PVAEL estimate 60 and of the PVCDGRP value 64 . The number ultimately used would have to be determined through negotiations and, or regulatory proceedings.
[0132] In 66 , the estimates of the reliability benefits credit from a market-design perspective 62 and from a reliability-design perspective 65 are reconciled through negotiations and, or regulatory proceedings into a mutually agreeable value. This reconciled reliability benefits credit (RRBC) could be determined in 66 by one of the following methods:
[0133] If the present value of avoided outage costs is to be used exclusively then
[0000] RRBC=PVAEL (7)
[0134] Depending on the value PVAEL attains, Equation (7) could produce either the lowest or highest credit values for market-design segmentation projects.
[0135] If the choice is to set the reliability credit at the highest possible value, RRBC would be determined by:
[0000] If PVAEL≦PVCDGRP then RRBC=PVCDGRP (8)
[0000] If PVAEL>PVCDGRP then RRBC=PVAEL (9)
[0136] If setting the reliability credit at the lowest possible value is preferred, RRBC would be decided by:
[0000] If PVAEL≦PVCDGMP then RRBC=PVAEL (10)
[0000] If PVAEL>PVCDGMP then RRBC=PVCDGMP (11)
[0137] Note that in the above relations, it is assumed that PVCDGMP is less than PVCDGRP. This assumption is correct to the extent that segmenting for market-design purposes would involve more gates than reliability enhancement projects. The relations expressed by (7) though (11) define the boundaries that the value of the reliability credit could take on. In this sense, they could serve as a road map for early exploration of the economics of market-design segmentation and setting public policy direction for how to encourage inter-regional investment in the new technology.
[0138] The RRBC value 66 is passed on to 67 where it is netted out from the gross cost of the optimal MDSS 11 . The gross cost estimate 11 is determined through the algorithm described in FIG. 4 . The final result 67 should provide the key information for determining the economic feasibility of any proposed market-design segmentation of an ac interconnection.
G. The Net Cost of a Fully Dynamically Secure Market-Enhancement Design
[0139] This last stage of the process is for deriving and netting out a reliability-benefits credit from the gross cost of segmenting an ac interconnection to establish a dynamically secure market design. The value of the credit could determine the economic viability of such projects. This algorithm to be used to achieve this goal is depicted in FIG. 10 .
[0140] The process for deriving the net cost of segmenting an ac grid for both market-design and dynamic security purposes ( FIG. 6 ) is quite similar to the one devised for solely market enhancement projects ( FIG. 9 ). Hence, some of the explanatory comments presented in Subsection II-F will not be repeated here. The first step is to identify and establish the costs of the dynamically critical gates for a fully secure MDSS 68 . This is accomplished in 68 by: (i) identifying the gates added to the optimal MDSS to achieve the desired increase in dynamic security; and (ii) combining this information with the list of the dynamically significant gates for the optimal MDSS case. The information needed for Item (i) is obtained by comparing the configurations of the optimal MDSS 10 (originally from 10 FIG. 4 ) and the fully secure MDSS 27 (originally from FIG. 5 ). The list of the dynamically significant gates for the optimal MDSS can be obtained from 60 in FIG. 8 .
[0141] Having identified the gates needed to provide the desired degree of protection for the interconnection against cascading outages, the present value of the total cost of implementing these gates is then calculated in 68 . Sponsors of market-design segmentation may want to strip away the economy of scale savings associated with increasing the size of the investment from the smaller set of the dynamically significant gates to the full set required for the market enhancement design. Hence, two estimates of a reliability credit based on the costs—from a market-design perspective—of implementing gates could emerge from 68 : a low PVCDGMP value that would reflect the economy of scale attainable with the larger investment in dc segmentation, and a high PVCDGMP value representing the costs of investing in only the gates needed to achieve full dynamic security.
[0142] To the extent PVAEL could be reliably estimated, it becomes a better measure of the avoided costs credit for market-design segmentation projects. The dominant contributor to this parameter is expected to be the economic worth of avoided outage-related losses for ratepayers. PVAEL is estimated in 70 by subtracting the present value of the residual cascading outage costs of the optimal dynamically secure MDSS (provided in 27 by way of FIG. 5 ) from the present value of the cascading outages that could have taken place in the absence of any level of segmentation (given by 48 by way of FIG. 7 ).
[0143] In 69 , PVAEL 70 is compared to PVCDGMP from 68 . If PVAEL is found to be the lower of the two, it sets the value of the reliability benefits credit from a market-design perspective (RBCMDP) 69 . If PVAEL is the greater of the two, PVCDGMP could act as a cap on what users of the grid are willing to pay to avoid the cascading outage risks. From a market-design perspective, the assessment boundaries for the cascading outages reduction credit could be determined by the expressions (3) and (4).
[0144] The formulation presented in (3) says grid users would not pay for a reliability credit greater than the value of potential avoided outage costs. However, sponsors of market-design segmentation may object to (4) as unjustifiable capping of the amount of deserved credit by the PVCDGMP estimate. In their view, the potential savings to be realized by users of the grid are better represented by PVAEL. In addition to this uncertainty, gate costs may or may not reflect the economy of scale savings that larger projects bring with them. In light of these potential differences between grid users and segmentation proponents, the reliability-benefits credit 69 will be bounded by the lower of PVAEL and the low value of PVCDGMP, and the higher of PVAEL and the high value of PVCDGMP. The estimate ultimately used would have to be determined through negotiations and, or regulatory proceedings.
[0145] Since any value assigned to the reliability benefit credit 69 would always represent a market-design perspective, an estimate from a reliability-design perspective (a PVCDGRP value) is needed. Such alternate valuation is provided in 71 by adjusting the costs in 68 of acquiring the dynamically significant gates by the level of economy (or diseconomy) of scale associated with the configuration and costs of segmenting the same system to only meet current and new reliability criteria 43 (originally from FIG. 6 ). Assuming the number of gates required to achieve the desired market segmentation is greater than what would be needed to only secure the system dynamically, the reliability-design estimate PVCDGRP would be lower than the PVCDGMP value of 68 .
[0146] In 72 , the estimates of the reliability benefits credit from a market-design perspective, RBCMDP, 69 , and from a reliability-design perspective, represented by PVCDGRP 71 , are reconciled through negotiations and, or regulatory proceedings into a mutually agreeable value. This reconciled reliability benefits credit for a market-design with full dynamic security (RRBCMDFDS), could be determined in 72 by one of the following methods:
If the present value of avoided outage costs is to be used exclusively then
[0000] RRBCMDFDS=PVAEL (12)
Depending on the value of PVAEL, Equation (12) could result in either the lowest or highest credit values for market-design with full dynamic-security segmentation projects. If the credit is to be set at the highest value, RRBCMDFDS would be determined by:
[0000] If PVAEL≦PVCDGRP then RRBCMDFDS=PVCDGRP (13)
[0000] If PVAEL>PVCDGRP then RRBCMDFDS=PVAEL (14)
If setting the credit at the lowest value is preferred, RRBCMDFDS would be decided by:
[0000] If PVAEL≦PVCDGMP then RRBCMDFDS=PVAEL (15)
[0000] If PVAEL>PVCDGMP then RRBCMDFDS=PVCDGMP (16)
[0151] In the above relations, it is assumed that PVCDGMP is less than PVCDGRP. This assumption-holds as long as segmenting for market-design purposes would involve more gates than reliability enhancement investments. The relations expressed by (12) though (16) define the quantitative limits that the value of the reliability credit could fall within.
[0152] The RRBCMDFDS value 72 is netted out, in 73 , from the gross cost of implementing the optimal dynamically secure MDSS (from 27 ) to produce the net cost 73 of segmenting an ac interconnection for both market-design purposes and to achieve the desired level of dynamic security against cascading outages. The final result 73 should furnish the key information for determining the economic feasibility of any proposed market-design and dynamic segmentation of an ac interconnection.
III. Inter-Market Transmission Access Optimization and Scheduling
[0153] The Inter-Market Transmission Access Optimization and Scheduling (IMTAOS) process fulfills the pressing need for a better way of utilizing existing and future transmission infrastructures. As stated before, IMTAOS accomplishes this feat by making use of (1) the complete controllability of power flows between trading grid sectors (regions) with the help of dc gates, and (2) the ability to expand ATC through the economic scheduling of counter-flows.
[0154] As shown in FIGS. 11 , 17 , 19 , and 21 , IMTAOS provides a novel process for optimizing and scheduling the allocation of inter-sector gate ATC among competing requests for transmission service during periods of normal grid operation.
[0155] Emergency conditions, which should be very rare in well performing grids, will require backup plans and operating procedures in the event of failure of power system elements. Such plans and operating procedures will have to be implemented to provide fast operator and automatic control responses to minimize the impact of loss of power system elements on scheduled transactions and on system reliability. The real-time scheduling-algorithms presented in FIGS. 19 through 22 could be an integral part of system recovery plans against major (or minor) loss of generation and/or load. Thus, although the novel allocation process is concerned with normal system operation, it could also be essential in emergency situations.
[0156] Recent and on-going efforts to restructure the electric power industry favor the development of multi-settlement systems comprising two or three of the following inter-related markets: the Day-Ahead (DA), Hour-Ahead (HA) and Real-Time (RT) markets. IMTAOS provides the means for optimizing the utilization of transmission systems for all three markets in an integrated manner as illustrated by FIGS. 11 through 16 , 17 , 18 , 19 and 20 , which depict the interactive applications of IMTAOS.
[0157] The invention also applies to regions that choose a 2-settlement structure, normally the DA and RT as has been envisioned in the Standard Market Design initiative of the U.S. Federal Energy Regulatory Commission (FERC). FIGS. 11 through 16 , 21 and 22 show how a 2-market system can be accommodated by IMTAOS.
[0158] In addition to the inter-temporal integration of markets, IMTAOS can also integrate markets of different regions if dc-aided segmentation for controlling inter-regional power flows were implemented. This crucial capability accomplishes two unprecedented feats: (1) matching and coinciding the contract path of any inter sector transaction with an identifiable physical path of the associated flow of electric power; and (2) full exploitation of counter-flows to maximize ATC in the direction of potential congestion. This is illustrated by the processes shown in FIGS. 11 through 22 .
A. The Normal Day-Ahead Inter-Sector Scheduling Process
1. Overview (FIG. 11)
[0159] The process shown in FIG. 11 generates optimal allocation of inter-sector ATC among DA inter-regional transmission service customers even if the collective demand for such service exceeded the ATC physically present.
[0160] The novel allocation process for normal system operation starts at 101 in FIG. 11 when market participants submit requests to their respective GOs and to ICC for transmission service to carry out inter-sector trades in the DA market. The GOs may impose different deadlines for submitting service requests as long as they are within a mutually agreeable cutoff time (probably between 7 a.m. and 10 a.m. on the day preceding the DA market; i.e., next day of actual grid operation).
[0161] In 102 , the GOs relay the requests for DA service to ICC along with intra and inter-sector system and market information that ICC would need to configure the optimal allocation of inter-sector ATC. The required data includes market clearing prices (MCPs), uplift charges (if applicable), cost of intra-sector transmission service and relevant transmission outages and losses.
[0162] ICC validates in 104 the submitted scheduling requests by cross checking the information it receives from the market participants and the GOs on the sending side with their counterparts on the receiving end. Unmatched requests 103 would be sent back to the GOs 102 for review and final consolidation. Only the matched scheduling requests are validated by ICC 105 . And only the validated schedules would be processed further.
[0163] In 107 , ICC makes use of its ability to control inter-sector flows through its network of gates to generate counterflows and to configure optimal routes to meet transmission customers' needs. The process encapsulated in 107 is detailed in FIGS. 12 through 16 . It requires GO and ICC system state and tariff data 106 and as indicated earlier in the description of 102 .
[0164] The process involving 107 would have to be carried out over at least two rounds. ICC submits the first round results of the optimally routed schedules 108 to the GOs for review and further action 109 . In 110 , the GOs will revise, if necessary, their DA dispatches and schedules, and submit any subsequent changes in the data they provided to ICC per 102 and 106 . ICC would then repeat 107 to generate a second round of counterflows and optimal routes for power delivery 108 . If the new schedules in 109 do not require significant revision of the GOs' DA dispatches, the process stops and ICC submits its final inter-sector schedules to the GOs 111 .
[0165] In 112 , the GOs formally accept ICC's schedules. This would allow ICC to bill its transmission customers for the inter-sector scheduling services it provided 113 .
2. Day-Ahead Transmission Routing Optimization (FIG. 12)
[0166] The objective of the DA transmission routes optimization process, as detailed by FIGS. 11 through 16 , is to achieve a least-cost joint-dispatch of the interconnection's network of dc gates while avoiding to the extent possible any curtailment of customers' schedules. The process starts with the ICC-validated schedules 105 of FIG. 11 . Using information provided in the customers' templates for service requests, the ICC identifies the service priority and dispatchability of the validated schedules 202 . Subsequently, the submittals are divided into two classes: high-priority schedules (HPS) 203 and low-priority schedules (LPS) 204 . The HPS represent customers who own firm-service rights over one or more gates. The LPS are for those who choose to seek inter-sector transmission service on an as-available basis. They do not own any rights on any gate. (If a customer owns rights on some gates and wants to schedule somewhere else, it could submit both types of schedule: HPS and LPS.)
[0167] The HPS and LPS are then dichotomized by their dispatchability (or lack thereof). HPS are divided into inflexible HPS (IHPS) and dispatchable HPS (DHPS). The former represents holders of rights who do not wish to decrement their schedules for any price they are offered. The DHPS are willing to give up certain portions of the capacity they hold in return for compensation. They essentially bid to supply capacity. The LPS is dichotomized similarly. However, the dispatchable LPS (DLPS) is a buyer of transmission service capacity at prices it is willing to bid. The inflexible LPS (ILPS) is willing to be served at essentially any price. It should be noted that the four categories represented by 205 , 206 , 207 and 208 encompass the widest spectrum of transmission customers. If intermediate or hybrid applications are encountered, one can decompose them into two or more of the aforementioned four schedule types.
[0168] Knowing the source (the electric bus, utility service area and sector of origin) and the ultimate destination (again the bus, utility and sector of the receiver), all possible routes (combinations of dc gates) would be devised using simple computer-aided comprehensive and systematic search routines. The only constraint on route synthesis is gate outages which are accounted for 210 . The end product of 209 is a set of alternative routes for each schedule. Depending on the number of gates available and the number of sectors involved, a schedule could have 210 or more routes. The implication of this type of result is a significant increase in transmission services liquidity: a sorely needed improvement over the status quo.
[0169] The next step 211 is to estimate the total cost of service for each possible route. This requires two sets of data. First, reliable estimates of the total gate-specific per-unit tariff charges 212 which in turn are generated by adding up the appropriate grid-service fees 213 (that GOs may require for intra-sector support services) and ICC gate access charges 214 . Both 213 and 214 could be affected by the schedule's service priority and dispatchability status. The second service category of needed cost information is the economic worth of transmission losses. This requires data on gate-specific transmission loss factors and value-of-generation (VOG) projections 215 . VOG estimates can be obtained from market data trackers or other means.
[0170] The route-specific total cost of service developed in 211 is contrasted with what the HPS have pre-paid (for the rights they acquired on their choice of routes) and what the DLPS is willing to pay for their schedules 217 . If the total cost of a route per 211 were to exceed the corresponding rates in 217 , said route would be declared financially infeasible. The result of combining the information in 211 and 217 is a reduction of the matrices of all possible routes 209 into a set of financially feasible schedule-specific routes 216 .
[0171] In 218 , the route matrices of 216 are reorganized into distinct (unique) configurations of schedule-specific, financially feasible routes 218 . Each configuration is in effect an alternate dc-network dispatch. Three conditions govern the synthesis of a configuration: (i) Every schedule must be part of every configuration; (ii) A schedule can appear only once in the configuration; and (iii) No route can be represented more than one time in a configuration.
[0172] The information in 218 is passed on to the algorithm of FIG. 13 : (i) Conduct gate congestion management (if needed); (ii) Enable the dispatch of every configuration of financially feasible routes 218 —if necessary—through congestion management and/or pro rata LPS curtailments; and (iii) Identify the optimal set of routes (configuration) for the validated schedules 108 .
3. The Physical Feasibility and Gate Congestion Management Algorithm (FIGS. 13A, B, C and D)
[0173] The purpose of this algorithm is to render all financially viable configurations physically feasible by conducting, where needed, gate congestion management. The logic presented in FIGS. 13A , B, C and D applies to DA, HA and RT schedules.
[0174] The primary tasks the algorithm performs are to:
[0175] Desegregate all schedules of all configurations into dominant and counter-flows (Steps 218 through 317 );
[0176] Ascertain which configurations are free of congested gates and which are not (Steps 218 through 319 );
[0177] Pluck out the congestion-free configurations and hand them over to a separate algorithm ( FIG. 14 ) for identifying the least-cost dispatch (Steps 319 through 322 );
[0178] Construct gate-specific supply (of dominant-flow decrements) and demand (for counter-flow adders) curves out of customers bids for congestion management purposes (Steps 323 through 335 );
[0179] Identify which (if any) of the congested configurations must be curtailed for lack of sufficient counter flow adders and dominant flow decrements (Steps 323 through 336 ) and to subject such configurations to pro rata curtailment using the algorithm of FIGS. 15 (Steps 336 through 338 );
[0180] Perform a least-cost congestion management for the uncurtailable configurations with the aid of the algorithm of FIGS. 16 (Steps 339 through 347 );
[0181] Subject curtailable configurations to pro rata curtailment (by way FIGS. 15 algorithm) if economic congestion management failed to produce uncongested gates (Steps 340 through 350 ); and
[0182] Hand over the congestion-cleared configuration to the algorithm of FIG. 14 to identify the least-cost dispatch.
4. The Algorithm for Identifying the Least-Cost Configuration (FIG. 14)
[0183] This algorithm determines the total cost of service for each competing configuration (Steps 320 through 417 ) and uses the results to identify the lowest-cost combination of routes as the optimal dispatch for the system 418 . The algorithm can be used for DA, HA or RT applications.
[0184] In addition to computing the cost of service (using tariff rates 410 for GO and gate ICC services, gate-specific loss factors, and VOG forecasts 215 and dispatch data 411 ), the algorithm also enables the assessment of (i) configurations' uplift charges (if the cost of buying dominant-flow decrements for DHPS holders exceeds the income from selling counter-flow adders to LPS applicants) (Steps 413 through 416 ); and (ii) configuration's surplus revenues (if the income from counter-flow sales surpass the payments for reducing dominant flows) (Steps 413 through 416 ).
5. The Algorithm for Pro Rata Curtailment (FIGS. 15A, B and C))
[0185] If none of the candidate configurations was capable of producing congestion-free dispatch, pro rata curtailment has to be invoked. The algorithm of FIGS. 15A , B and C accomplishes this task for DA, HA and RT applications. The algorithm ensures that only the schedules contributing to dominant flows (i.e., those that created the congestion) are curtailed (Steps 510 through 513 in the do-loop 504 to 532 ) and that out of this group only the LPS are subjected to pro rata reductions in the requested amounts of service (Step 511 ). The identified curtailable LPS are then pro rata adjusted to eliminate congestion (Steps 516 through 529 ).
[0186] As each gate is cleared of congestion, the algorithm assesses the impacts on the scheduling of cohort gates because of the invoked changes in the LPS schedules they share (Steps 519 through 527 ). All needed adjustments are implemented before moving on to the next gate 526 . The algorithm is designed to proceed in order of decreasing gate congestion 506 .
[0187] In addition in curtailing certain schedules to clear congestion, the algorithm also keeps track of the total amount of curtailments implemented for each configuration 528 . And since pro rata reduction of customers' schedules does not involve paying for dominant-flow reductions or selling capacity in the direction of counterflows, uplift charges and revenues are set to zero 530 .
[0188] The end product of the FIGS. 15A , B and C algorithm is a set of financially viable and physically feasible (by way of pro rata curtailments) configurations 320 . This information is then passed on to the algorithm of FIG. 14 (to identify the least-cost dispatch among the competing curtailed configurations). Finally, it should be noted that the FIGS. 15A , B and C algorithm will be used only if no configuration free of congestion could be found and economic congestion management was not sufficient. Curtailment of schedules is a last resort option.
6. The Algorithm for Least-Cost Congestion Management (FIGS. 16A, B and C)
[0189] This algorithm exercises market-based management of congestion if: (i) no congestion-free configuration can be found; and (ii) curtailment of schedules can be avoided. It can be used for DA, HA and RT applications.
[0190] The objective function of the algorithm is to achieve least-cost resolution of congestion on a gate-by-gate basis. Using congestion management demand and supply (the CMD and CMS) curves from the algorithm of FIG. 13 , congestion is eliminated at the current gate i by purchasing dominant-flow reductions from DHPS customers (i.e., moving down the CMD curve) 601 , 602 and 603 .
[0191] The outcome of moving along the CMD and CMS curves could be one of the following:
The prices demanded by DHPS sellers do not intersect with the prices offered by DLPS buyers at any level of dispatch: In this case, clearing congestion at the gate could either generate a surplus (if the total collected from DLPS sales exceeds the total paid out for DHPS purchases) or deficit (if payments to DHPS exceed the income from DLPS). In the latter situation, an uplift charge would be required. The treatment of surpluses would have to be decided through regulatory proceedings. The two curves intersect at a unique point: Requiring (as is commonly practiced by grid operators) that bidders on both sides submit either single-quantity/single-price bids or multi-point monotonically increasing (for DHPS sellers) and monotonically decreasing (for DLPS buyers) offers, increases the chances of the intersection of the CMD and CMS curves at such unique point: the market clearing price (MCP) for congestion management. If the total of the schedule adjustments at the MCP turns out to be equal to or greater than what is needed to clear the congestion, the gate is revenue neutral: the amount paid to DHPS sellers equals what is paid by the DLPS buyers. If congestion resolution requires more adjustments, than can be obtained at the MCP, an uplift charge would be required. Depending on the results from 601 , the algorithm calculates either a gate uplift 605 or a gate surplus 606 . It should be emphasized that the objective function stated in 601 (i.e., the minimization of the net cost of congestion management) ensures a least cost adjustment of each gate's dispatch.
[0194] The next task for the algorithm is to decompose the CMS purchase(s) and CMD sale(s) into the specific DHPS and DLPS contributors 607 and 608 , respectively. This information is then used to update the DHPS and DLPS levels at the current gate 609 and 610 , and at the cohort gates (i.e., those sharing the affected schedules with the current gate) 612 through 628 . The adjustments of the flows on the cohort gates are performed in a way that ensures accurate updating and tracking of dominant flows and counterflows 619 and 620 . Steps are also taken to recalculate the over-scheduling delta for each inadvertently affected gate 625 and to restructure the CMD and CMS curves for such cases 626 .
[0195] Having made the necessary scheduling adjustments, the algorithm then checks whether any of the cohort gates has been inadvertently rendered curtailable 627 through 633 . The number of curtailable gates is then passed on to 344 in FIG. 13C for eventual pro rata curtailment.
B. The Normal Hour-Ahead Inter-Sector Scheduling Process
[0196] The HA process as exhibited in FIGS. 17 and 18 is essentially the same as the one for DA applications. With one exception, the description provided for FIGS. 11 and 12 applies here and will not be repeated. The difference between the two cases is the existence of committed DA schedules for the HA application. This is accounted for by 112 in FIGS. 17 and 18 . In FIG. 17 , accepted DA schedules 112 from FIG. 11 are included in the inputs into the HA transmission routes optimization process 707 . In FIG. 18 , the DA schedules 112 are incorporated as part of the set of HA inflexible high-priority schedules (HAIHPS) 805 . The rest of the optimization process proceeds as described for the DA application. The needed supporting algorithms are exactly the same as those used in FIG. 12 , starting with 219 of FIGS. 12 and 18 .
C. The Normal Real-Time Inter-Sector Scheduling Process for Three-Settlement Systems
[0197] As in the case of the HA application, the RT process represented by FIGS. 19 and 20 is essentially the same as the one for DA applications. With two exceptions, the description provided for FIGS. 11 and 12 applies here and will not be repeated. The differences between the two cases are: (i) the existence of committed DA and HA schedules for three-settlement system applications; and (ii) The absence of the GO review cycle (Steps 109 and 110 in FIG. 11 ) because of the impracticality of carrying out such steps in the limited time available before actual dispatching takes place. The presence of DA and HA scheduled capacity commitments is accounted for by 112 and 712 in FIGS. 19 and 20 , respectively. In FIG. 19 , accepted DA and HA schedules 112 and 712 are included in the inputs into the RT transmission routes optimization process 907 . In FIG. 20 , the DA and HA schedules 112 and 712 are incorporated as part of the RTIHPS 1004 . The rest of the optimization process proceeds as described for the DA application. The needed supporting algorithms are exactly the same as those used in FIG. 12 , starting with 219 of FIGS. 12 and 20 .
D. The Normal Real-Time Inter-Sector Scheduling Process for Two-Settlement Systems
[0198] Again, the RT process for two-settlement systems as depicted in FIGS. 21 and 22 is essentially the same as the process for DA applications. With two exceptions, the description given for FIGS. 11 and 12 applies here and will not be repeated. The differences between the two cases are: (i) the existence of committed DA schedules for two-settlement system applications; and (ii) The absence of the GO review cycle (Steps 109 and 110 in FIG. 11 ) because of the impracticality of carrying out such steps in the limited time available before actual dispatching takes place. The presence of DA scheduled capacity commitments is accounted for by 112 in FIGS. 21 and 22 . In FIG. 21 , accepted DA schedules 112 are included in the inputs into the RT transmission routes optimization process 1101 . In FIG. 22 , the DA schedules 112 are incorporated as part of the RTIHPS 1201 . The rest of the optimization process proceeds as described for the DA application. The needed supporting algorithms are exactly the same as those used in FIG. 12 , starting with 219 of FIGS. 12 and 22 .
[0199] A variety of modifications, changes and variations to the invention are possible within the spirit and scope of the following claims. The invention should not be considered as restricted to the specific embodiments which have been described and illustrated with reference to the drawings.
BIBLIOGRAPHY
[0000]
[1] M. Kumbale, T. Rusodimos, F. Xia, and R. Adapa, TRELSS: A Computer Program for Transmission Reliability Evaluation of Large-Scale Systems, EPRI TR-100566 3833-1, Vol. 2, April 1997.
[2] see for example: (1) Y. V. Makarov and R. C. Hardiman, “Risk, Reliability, Cascading, and Restructuring”, CIGRE/IEEE Quality and Security of Electric Power Delivery Systems, Montreal, Quebec, Canada, 7-10 Oct. 2003; and (2) R. C. Hardiman, M. Kumbale, and Y. V, Makarov, “Multi-Scenario Cascading Failure and Analysis Using TRELSS”, CIGRE/IEEE, PES International Symposium on Quality and Security of Electric Power Delivery Systems, Montreal, Quebec, Canada 7-10 Oct. 2003.
[3] Roy Billington and Ronald N. Allan, “Reliability Evaluation of Engineering Systems Concepts and Techniques”, Plenum Press (1992).
[4] See for example the reference cited in Footnote 1.
[5] See J. Wang, “Efficient Monte Carlo Simulations Methods in Statistical Physics”, Department of computational Science, National University of Singapore, Singapore, Mar. 15, 2001.
[6] See for example the references cited in [2].
[7] See for example the references cited in [1].
[8] See for example the references cited in [2].
[9] See for example the reference cited in Footnote [1].
[10] See for example: Hiller, Frederick S. and Gerald I. Lieberman, “Operations Research”, Holden-Day, Inc. (1974).
[11] See [3], [5] and [10]. See also: (1) 5. Burns and G. Gross, “Value of Service Reliability”, IEEE Trans. Power Syst., Vol. 3, pp. 825-834, August 1990; and (2) S. Yin, R. Chang and C. Lu, “Reliability Worth Assessment of High-Tech Industry”, IEEE Trans. Power Syst., Vol. 18, No. 1, pp. 359-365, February 2003.
GLOSSARY
[0211] CDF Curtailable Dominant-Flows
[0212] CFS Counter-Flow Schedules
[0213] CLPS Curtailable Low-Priority Service
[0214] CLPSS Curtailable Low-Priority Service Schedules
[0215] CMD Congestion Management Demand Curve
[0216] CMS Congestion Management Supply Curve
[0217] COG Capacity of Gate
[0218] COS Cost of Service
[0219] DA Day-Ahead
[0220] DFS Dominant Flow Schedules
[0221] DHPS Dispatchable HPS
[0222] DLPS Dispatchable LPS
[0223] DOSD Estimated Difference in OSD
[0224] GO Grid Operator
[0225] GR Gate Revenue
[0226] GS Gate Surplus Revenues
[0227] GU Gate Uplift Charge
[0228] HA Hour-Ahead
[0229] HPS High-Priority Schedules
[0230] ICC Interconnection Coordination Center
[0231] IHPS Inflexible HPS
[0232] ILPS Inflexible LPS
[0233] LPS Low-Priority Schedules
[0234] LPSS Low-Priority Service Schedules
[0235] MS Modified Schedules
[0236] MXD Maximum Demand
[0237] MXS Maximum Supply
[0238] NCMC Net Cost of Congestion Management
[0239] NCS Number of Curtailable Schedules
[0240] NFC Number of Feasible Configurations
[0241] NGF Net Gate Flow
[0242] NMS Number of Modified Schedules
[0243] NOCC Number of Curtailable Configurations
[0244] NOCG Number of Curtailable Gates
[0245] OLDHPS Old Value of DHPS
[0246] OLDLPS Old Value of DLPS
[0247] OSD Over-Scheduling Delta
[0248] PD Price of Demand Bids
[0249] PS Price of Supply Bids
[0250] RT Real Time
[0251] TCC Total Configuration's Curtailments
[0252] UC Uncurtailable Configurations
[0253] VOG Value of Generation | 4y
|
FIELD OF THE INVENTION
This invention relates to methods and compositions for fracturing subterranean formations. In particular, it relates to a dry mix formulation forming a crosslinking polymer which may be prepared in one step by adding water.
BACKGROUND ART
Fracturing fluids comprising gels and crosslinked gels are widely used to fracture subterranean formations so as to allow the flow of fluids such as oil and gas therethrough, and make these hydrocarbon materials accessible to pumping. Gels, which can carry particulate propping agents to keep the fracture open, are preferred fracturing fluids. Crosslinked gels are preferred as having better pumping characteristics. In general such crosslinked polymers comprise an aqueous liquid, a gelling agent and a crosslinking compound. The gelling agents in general are hydratable polysaccharides having molecular weights greater than about 100,000. These include galactomannan gums, glucomannan gums, and cellulose derivatives. Among the most widely used gelling agents in the industry at the present are hydroxypropylguar gums (HPG), hydroxyethycellulose (HEC), and the carboxymethyl-substituted derivatives of each, carboxymethylhydroxypropylguar (CMHPG) and carboxymethylhydroxyethylcellulose (CMHEC). Crosslinking agents include compositions, preferably organic compositions, containing polyvalent metal ions, especially metal ions capable of +3 and +4 valent states, such as Al +3 , Ti +4 and Zr +4 . The pH affects the speed of hydration of the gelling agent as well as the speed of crosslinking, and pH-adjusting agents are often included in the fracturing fluid mix. Commonly used pH-adjusting agents are hydrochloric acid, fumaric acid, and phthalic acid, as well as potassium biphthalate, sodium hydrogen furmarate and sodium dihydrogen citrate, to name only a few.
It is desirable in using crosslinked gels for fracturing subterranean formations that the crosslinking reaction proceed while the gel is traversing the tubular goods toward the formation. If crosslinking occurs either in or prior to entering the pumps, pumping difficulties may be encountered. If crosslinking does not occur before the gel reaches the formation, the gel will not have the viscosity required to place large quantities of proppant in the formation. Typically, gelling compositions hydrate rapidly. Because it is desirable for the gelling composition to be as completely hydrated a possible prior to addition of the crosslinking agent, prior art processes have relied on prehydration of the gelling composition in storage tanks prior to the addition of the crosslinking agent. Quality control of the final mix is sometimes difficult, and it often happens that injection pumps will be slightly out of adjustment for purposes of providing the proper flow rate for the amount of crosslinking agent being added to the gel as it is being pumped into the formation. With too much crosslinking agent, the composition gels too much or too fast for optimum flow into the formation, and with too little crosslinking agent, the composition will be too thin to advantageously effect fracturing. Adding the crosslinking agent to the gelling composition in the storage tanks would only exacerbate pumping and removal problems due to tremendous viscosity increases. Further, if the crosslinking agent becomes active before the gelling composition is completely hydrated, further hydration is essentially halted and peak viscosity will never be reached, resulting in an inferior fluid.
It is desirable that both hydration of the gelling composition and crosslinking be accomplished during the period the fracturing fluid is traveling down the well bore, so as to allow the fluid to be easily pumped, yet be viscous enough in the formation to accomplish the desired fracturing and proppant transport. It would be highly advantageous to provide prepackaged mixtures of all the dry ingredients required for the crosslinked polymer, including the crosslinking agent, in the appropriate proportions, so that it is necessary only to add these dry ingredients to the water or aqueous liquid being pumped down the well into the formation to enable mixing and pumping on a continuous basis without the need for pregelling tanks.
PRIOR ART STATEMENT
U.S. Pat. No. 3,888,312 to Tiner, et al., describes the use of organotitanates having titanium in the +4 oxidation state as crosslinking agents for a number of gelling compositions, including the gelling compositions of this invention. However, this process requires pre-mixing of the gelling agent with an aqueous solution to form a base gel. The crosslinking agent is then added to the base gel as it is being pumped into the well bore, to allow the cross-linking reaction to take place while the gel is moving into the formation. This patent does not disclose a method for pre-mixing the dry ingredients in appropriate proportions so as to eliminate the need for operator discretion and overcome the effects of faulty pumping equipment which causes the crosslinking agent to be added at too great or too small a rate to provide for the correct viscosity at the correct time.
U.S. Pat. Nos. 4,021,355 and 4,033,415 to Holtmyer, et al., describe the use of a number of gelling compositions, and a number of crosslinking agents including lead +2 , arsenic +3 , tin +2 , antimony +3 , antimony +5 , titanium +4 , manganese +7 , chromium +10 , tantalum +5 , and niobium +5 . The effect of pH on hydration of the gel and crosslinking is discussed in these patents. Critical pH ranges for operation of a number of the enumerated crosslinking agents are provided. These patents teach that raising pH will slow hydration of the gelling composition and prevent lumping thereof. These patents do not teach use of pH control to balance hydration time for the gelling agent with crosslinking time in order to provide a total dry mix crosslinked polymer as is provided by the present invention.
U.S. Pat. No. 4,313,834 to Harris describes the use of zirconium salts to crosslink pre-hydrated aqueous gels having high acidities.
Copending application Ser. No. 140,738, of Pabley, assigned in common with this application, describes the formation of acidic crosslinked polymers utilizing xanthan biopolymer, CMHEC and CMHPG as gelling compositions and hafnium, titanium, and zirconium-containing compositions as crosslinking agents to form an acidic crosslinked polymer having a pH less than 1.
U.S. patent application Ser. No. 140,737, of Pabley, assigned in common with this application, describes a process for forming an acid crosslinked polymer utilizing CMHPG and CMHEC as the gelling compositions, in combination with crosslinking agents containing titanium, zirconium, or hafnium, and hydrochloric acid from 1 to 15 weight percent in combination with hydrofluoric acid from 0.2 to 6 weight percent.
Neither of the foregoing applications provides a dry mix capable of forming a crosslinked polymer when water only is added.
BRIEF DISCLOSURE OF THE INVENTION
A method and composition for fracturing subterranean formations is provided involving a fracturing fluid comprising (a) a gelling composition which is a solvatable polysaccharide; (b) a crosslinking agent which is a compound containing a tri- or tetravalent metal; (c) a pH-adjusting agent. The relative proportions of the foregoing may be varied within limits known to the art. The specific components of the dry mix are selected so that the gelling composition is substantially completely hydrated by the time the crosslinking agent has dissolved. Thus, the polymer chains have been completely unrolled and are ready to be crosslinked by the time the polyvalent metal ion is in solution and capable of acting to crosslink the chains. If the crosslinking agent acts before the gelling agent is completely hydrated, further hydration is prevented, and peak viscosity will not be reached. Often some sacrifice of peak viscosity is necessary, but desired viscosities can still be achieved by the use of higher proportions of gelling agent to water or other aqueous hydration agent than would otherwise be required. The pH-adjusting agent is selected with respect to the specific gelling composition and the specific crosslinking agent. It is known to the art that specific combinations of gelling composition and crosslinking agent have operative and optimal pH ranges specific to these combinations. Within these limits, the rate of crosslinking tends to speed up with lower pH and slow down with higher pH. The activity of the crosslinking agent is further slowed by using a dry, powdered form thereof rather than a liquid form, and retarding the solubility thereof to the desired degree. By adjusting the pH of the system and the solubility of the crosslinking agent, so as to optimize the beginning of the crosslinking reaction and its rate with respect to the hydration rate of the gel, and the time necessary for the fracturing fluid to reach the formation, it is possible to provide a prepackaged dry mix which will provide the desired crosslinking within the desired time period with the addition of water only. The peak viscosity of the fracturing composition may be varied as desired by varying the amount of water added, the proportion of crosslinking agent to gelling composition remaining constant.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The premix for the fracturing fluid of this invention comprises a gelling composition which is a solvatable polysaccharide having a molecular weight of at least about 100,000. This includes the galactomannan gums, glucomannan gums, and cellulose derivatives. Cellulose derivatives are rendered solvatable by reacting cellulose with hydrophyllic constituents. Guar gum, locust bean gum, karaya gum, sodium carboxymethylguar, hydroxyethylguar, sodium carboxymethlhydroxyethylguar, hydroxypropylguar, sodium carboxymethylhydroxypropylguar, sodium carboxymethylcellulose, sodium carboxymethylhydroxycellulose, and hydroxyethylcellulose are examples of useful gelling compositions. Preferred gelling compositions are hydroxypropylguar, hydroxyethylcellulose and the carboxymethyl-substituted derivatives of each, carboxymethylhydroxypropylguar (CMHPG) and carboxymethylhydroxyethylcellulose (CMHEC), with the carboxymethyl-substituted derivatives of each (CMHPG and CMHEC) being most preferred.
The crosslinking agents are compositions containing polyvalent metal ions, preferably metal ions having a valence of +3 or +4, more preferably compositions containing zirconium +4 ions, and most preferably zirconium acetal acetonate.
A pH-adjusting agent, or buffer is added to the system as necessary to adjust the pH to optimise the hydration of the gelling composition, the dissolution and activation of the crosslinking agent, and provide the necessary acidity to react with materials, such as basic clay minerals, in the formation as desired. Raising the pH of the composition has a slowing effect on the hydration of some gelling compositions. Raising the pH may also retard the activity of the crosslinking agent, but the effect of pH on both of these rates is not necessarily uniform. Since it is desirable that the gelling composition be hydrated prior to the time the crosslinking agent becomes active, it will be necessary to determine the exact pH required for the specific gelling composition and the specific crosslinking agent to be utilized, and then to select the pH-adjusting agent accordingly. Any acidic or basic material may be used to adjust pH which does not adversely react with the other materials present in the system. Examples of suitable pH adjustors are hydrochloric acid, fumaric acid, phthalic acid, potassium, biophthalate, sodium hydrogen fumarate, sodium dihydrogen citrate, adipic acid, disodium phosphate, sodium carbonate, sodium diacetate, and sulfamic acid, and more preferably furmaric acid, sodiumdiacetate, and sulfamic acid, with sodium diacetate, fumaric acid and sodium bicarbonate being most preferred.
The proportions of crosslinking agent to gelling composition are in the range of between about 1:5 and 1:10, preferably between about 1:7 and about 1:9, and most preferably about 1:8. The amount of pH-adjusting agent will depend upon the pH-adjusting agent used and the desired final pH, and will generally be at a ratio to gelling composition of between about 1:5 and about 1:20, preferably between about 1:7 and about 1:9, and more preferably about 1:8. The final pH will depend upon the combination of gelling composition and crosslinking agent chosen, as well as upon the makeup of the subterranean formation, and will generally be between about 2 and about 8.5, more preferably between about 4 and about 7.5, and most preferably between about 5 and about 6.
The physical form in which the crosslinking agent is provided in the mix is selected so as to provide a solubility rate compatible with the hydration rate of the gelling composition. Preferably all the gelling composition has been hydrated prior to dissolution of the crosslinking agent. Slowly soluble crosslinking agents such as zirconium acetyl acetonate are thus preferred. The size of the particles of the crosslinking agent may be altered to affect its solubility. The particles may also be pretreated with such compositions as wax to retard their solubility. The desired solubility rate for the crosslinking agent will be such that the crosslinking agent does not substantially act until the gelling compositions is well-hydrated. Preferably, a commercially available crosslinking agent such as powdered zirconium acetyl acetonate made by Kay Fries Company of Stoney Point, N.Y. or Harshaw Company of Los Angeles, Calif. is used for reasons of process economy.
The dry mixed ingredients are blended to disperse the crosslinking agent and pH-adjusting agent uniformly throughout the gelling composition. Propping agents (including sand, bauxite and other particulate materials known to the art) may be added to the dry ingredients.
The dry mix is added to an aqueous stream as it is pumped into the well. Rapid hydration of the gelling composition is facilitated by the turbulence of the material in the well bore. The aqueous stream may be aqueous liquid, including hard water, having a chloride concentration up to about 3,000 ppm, and preferably less than about 2,000 ppm.
The proportion of dry mixed ingredients to water will be a function of the desired peak viscosity. In general, for a desired peak viscosity of between about 800 CPS and about 2,000 CPS and about 9.6 grams of dry mix per liter of water will be utilized. The relationship between peak viscosity and ratio of gelling composition to water is well known to the art when pregelling tanks are used. However, if the gelling composition is not 100 percent hydrated when the crosslinking agent becomes active, as may occur in the practice of this invention, when the solubility of the crosslinking agent is not precisely fitted to the hydration rate of the gelling composition, the ability of the gelling composition to bind up the water will be less than the norm for the same gelling composition and the same crosslinking agent when the gelling composition is prehydrated in a gelling tank prior to the addition of the crosslinking agent. The proportion of the dry mixed ingredients to water must therefore be increased over that of prior art processes when practising the process of this invention, typically in an amount of between about 0.4 and about 0.6 weight percent, preferably between about 0.45 and about 0.55 percent, and most preferably between about 0.47 and about 0.52 percent, for any given desired viscosity. The precise increase will, of course, depend on the particular crosslinking agent and gelling composition used, and should be minimized within the limits dictated by process economies. Complete gellation of the fracturing fluid, including crosslinking thereof, will generally occur in a period of time specific for the particular gelling composition and crosslinking agent selected, dependent on the temperature of the formation, although it may be somewhat speeded or retarded within the operative pH limits for the reaction by adjusting the pH. In general, matching of the gellation time with the amount of time required for the fracturing fluid to reach the bottom of the well bore will be controlled by varying the pumping rate.
The duration necessary for completion of the crosslinking reaction will also depend upon the temperature within the well bore. In general, the crosslinking reaction goes to completion within the range of about 80° F. to about 130° F. with no problem.
The final crosslinked fracturing fluid will have a viscosity of between about 800 and about 2,500, preferably between about 1,000 and about 2,000, and most preferably between about 1,200 and about 1,600, which is comparable to prior art fracturing fluids requiring prehydration of the gelling composition in gelling tanks.
The invention is illustrated by the following examples:
EXAMPLE 1
At ambient temperature, 20 grams CMHEC was thoroughly blended using powder rollers with 2.5 grams zirconium acetyl acetonate (solubility about 1.2 minutes in water) and 2.5 grams sodium diacetate. The dry ingredients were dispersed in tap water at a concentration of 50 lbs/1,000 gal. The final pH was 5.5. Crosslinking occurred in one minute.
EXAMPLE 2
At ambient temperature, 40 grams HPG was thoroughly blended using powder rollers with 5 grams zirconium acetyl acetonate and 5 grams sodium diacetate. The dry ingredients were dispersed in tap water at a concentration of 50 lbs/1,000 gal. The final pH was 5.29. Weak crosslinking developed.
EXAMPLE 3
At ambient temperature, 40 grams CMHEC was thoroughly blended using powder rollers with 5 grams aluminum acetyl acetonate (solubility about 45 seconds) and 5 grams sodium diacetate. The dry ingredients were dispersed in tap water at a concentration of 50 lbs/1,000 gal. The final pH was 5.5. No crosslinking occurred.
EXAMPLE 4
At ambient temperature, 40 grams CMHEC was thoroughly blended using powder rollers with 5 grams potassium pyroantimonate (solubility about 30 minutes) and 5 grams sodium diacetate. The dry ingredients were dispersed in water at a concentration of 50 lbs/1000 gal. The final pH was 5.36. No crosslinking occurred.
EXAMPLE 5
At ambient temperature, 40 grams CMHEC was thoroughly blended using powder rollers with 5 grams potassium pyroantimonate and 5 grams sulfamic acid. The dry ingredients were dispersed in tap water at a concentration of 50 lbs/1,000 gal. The final pH was 4.46. No crosslinking occurred.
EXAMPLE 6
At ambient temperature, 20 grams HEC was thoroughly blended using sand rollers with 2.5 grams zirconium acetyl acetonate and 2.5 grams sodium diacetate. The dry ingredients were dispersed in tap water at a concentration of 50 lbs/1,000 gal. The final pH was 5.5. No crosslinking occurred.
EXAMPLE 7
At ambient temperature, 40 pounds CMHPG was thoroughly blended for 30 minutes using powder rollers with 5 pounds zirconium acetyl acetonate and 5 pounds sodium diacetate. The dry ingredients were dispersed in tap water at a concentration of 50 lbs/1,000 gal. and stirred with a Waring blender. The final pH was 5.73. Crosslinking occurred in 41.1 seconds.
EXAMPLE 8
At ambient temperature, 40 grams CMHPG was thoroughly blended using powder rollers with 5 grams zirconium acetyl acetonate and 5 grams powdered fumaric acid. The dry ingredients were dispersed in tap water at a concentration of 50 lbs/1,000 gal. The final pH was 4.96. Crosslinking occurred in 1 minute 4 seconds.
EXAMPLE 9
At ambient temperature, 40 grams CMHPG was thoroughly blended using powder rollers with 5 grams zirconium acetyl acetonate, 5 grams aluminum acetyl acetonate, and 5 grams sodium diacetate. The dry ingredients were dispersed in tap water at a concentration of 50 lbs/1,000 gal. The final pH was 4.78. Crosslinking occurred in 58.8 seconds.
EXAMPLE 10
At ambient temperature, 40 grams CMHPG was thoroughly blended using powder rollers with 5 grams zirconium acetyl acetonate, 13 grams aluminum acetyl acetonate, and 5 grams fumaric acid. The dry ingredients were dispursed in tap water at a concentration of 50 lbs/1,000 gal. The final pH was 4.89. Weak crosslinking occured in 2 minutes 30 seconds.
EXAMPLE 11
At ambient temperature, the formula of Example 1 was dispersed in aqueous solutions having varying pH's at a concentration of 50 lbs/1,000 gal. The pH's of the aqueous solution, pH's of the mixture after addition of the dry ingredients, hydration time and crosslink time are set forth below in tabular form:
______________________________________Beginning pH After Hydration CrosslinkingAqueous pH Mixing Time (sec.) Time (sec.)______________________________________2.99 4.78 30 903.02 4.96 60 N.A.3.54 4.90 30 <603.54 5.20 60 1203.96 4.94 30 <604.01 5.28 >30 604.50 5.32 >30 604.51 4.94 30 504.98 4.98 30 <605.06 5.35 >30 605.48 4.99 20 455.57 5.35 >30 456.02 5.04 20 456.08 5.36 >30 406.55 5.44 30 557.05 5.42 <30 457.49 5.43 <30 407.96 5.43 >30 >458.12 5.47 <30 508.47 5.48 <30 509.03 5.47 >30 559.08 5.56 <30 609.56 5.46 <30 6010.0 5.67 <30 >6010.06 5.49 <30 6010.88 5.60 <30 6011.03 5.93 <40 >6011.07 5.79 <30 6011.25 6.19 30 6811.51 7.14 45 N.A.11.52 6.83 45 N.A.12.00 9.86 60 N.A.______________________________________
EXAMPLE 12
The formula of Example 1 was hydrated with water containing 2 percent potassium chloride at various temperatures, to a concentration of 2,000 ppm, and the crosslink time measured. Results are set forth in tabular form below:
______________________________________Temp. (°F.) Cross-link Time (sec.)______________________________________-2 N.A. 34 240 (weak) 45 90 72 <60100 <60110 60130 50 (weak)150 N.A.______________________________________
EXAMPLE 13
The formula of Example 1 (formula 1) was compared with formulas containing two buffers. Each formula was hydrated with water to a concentration of 50 lbs/1,000 gal. at two different pH's. The formulas are as follows:
______________________________________Formula 1: 40 pounds CMHEC 5 pounds zirconium acetyl acetonate 5 pounds sodiumdiacetateFormula 2: 40 pounds CMHEC 5 pounds zirconium acetyl acetonate 4 pounds sodium diacetate 1 pound sodium bicarbonateFormula 3: 40 pounds CMHEC 5 pounds zirconium acetyl acetonate 4.5 pounds sodiumdiacetate .5 pounds sodium carbonate______________________________________
The results are set forth in tabular form below:
______________________________________ Beginning pH After Hydration Cross-linkFormula Aqueous pH Mixing Time (sec.) Time (sec.)______________________________________1 6.90 5.55 <30 <451 11.01 6.07 <30 <902 7.00 6.05 <30 <902 11.04 6.83 <30 N.A.3 6.93 6.24 <30 N.A.3 11.02 7.35 <30 N.A.______________________________________
EXAMPLE 14
At ambient temperature, 45 pounds CMHEC was thoroughly blended using powder rollers with 5 pounds zirconium acetyl acetonate, 1 pound sodium bicarbonate, and 4 pounds fumaric acid having a particle size of 80 mesh (Tyler). The dry ingredients were dispersed in aqueous solutions having different pH values, at a concentration of 50 lbs/1,00 gal. Results are set forth in tabular form below:
______________________________________Beginning pH After Hydration Time Cross-link TimeAqueous pH Mixing (sec.) (sec.)______________________________________9.48 5.60 <30 3007.00 6.40 <30 100______________________________________
Although the foregoing invention has been described in some detail by the way of illustration and example for purposes of clarity of understanding, it will be obvious that certain changes and modifications may be practiced within the spirit of the invention, as limited only by the scope of the appended claims. | 4y
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RELATED APPLICATIONS
This is a division of U.S. application Ser. No. 09/273,432, filed Mar. 22, 1999, now U.S. Pat. No. 6,347,708.
FIELD OF THE INVENTION
The present invention relates to vibratory devices such as vibrating screens for classifying aggregate and vibratory feeders for feeding aggregate to crushing and processing devices. More specifically, the present invention relates to an improved wheel case for housing the rotating components of the vibratory devices and for protecting those components from the loss of lubricant and/or from the ingress of contaminants.
BACKGROUND OF THE INVENTION
Vibrating screen devices and vibrating feeder devices are generally well known in the art. On a typical vibrating screening device, a system of classifying screens are mounted to a frame which in turn is supported on a system of springs. At or near the center of the device is an eccentrically weighted shaft unit, typically having one, two, or three or more rotating and eccentrically weighted shafts. On a multi-shaft unit, the shafts may be counter-rotating such that the eccentric weights are oriented in the same direction twice each revolution. This causes the screen to vibrate, which aids the classifying effects of the screen device. On a vibrating feeder, a similar shaft unit vibrates the feed trough or chute, which “throws” the aggregate contained in the trough in a desired direction. An example of such a device can be found in U.S. Pat. No. 4,340,469 issued to Archer.
The ends of the rotating shafts are supported by bearings, and each shaft includes a drive wheel or gear. The shaft drive gears are operatively coupled to an external drive motor. The eccentric weights are typically attached to the ends of the shafts adjacent the drive wheels. The bearings and the drive wheels require constant lubrication, and thus such components are disposed within a wheel housing or case containing a quantity of oil or other suitable lubricating fluid. The wheel case is typically bolted to the frame of the vibratory device.
Historically, conventional cap screws have been used to secure the wheel case to the frame of the vibratory device. However, due to the constant vibration, coupled with the constant exposure of the cap screws to the lubricating oil, such conventional cap screws are subject to loosening. The loosened cap screws provide a convenient avenue for oil loss, and also provide a convenient avenue for the ingress of dirt, water, and other contaminants. Moreover, the cap screws are not readily accessible for the purposes of re-tightening.
Accordingly, threadless fasteners have been used, such as the threadless fastener sold under the trade name Huckbolt® manufactured by the Federal Mogul Corporation. Such a fastener has a threadless collar that is pressed onto the bolt shank using hydraulic means. The collar engages a series of annular rings spaced along the bolt shank. Such bolts typically provide consistent clamping force and exhibit high resistance to loosening in most applications. However, such bolts may experience loosening when used in highly lubricated, vibrating environments, thus leading to the leakage problems outlined above. Such bolts are not easily re-tightened, and as outlined above, it is not easy to access the securing bolts in any event.
In addition to the problems with oil loss and contaminant ingress, both of which lead to premature failure of the gears and/or the bearings housed within the wheel case, a loose bolt also causes the holes through the bolted components to enlarge, thus accelerating the loss of oil or the ingress of contaminants. Moreover, loose bolts permit small pieces of aggregate to become lodged between the various bolted components, rendering it impossible to securely bolt the components together without completely disassembling and cleaning the device.
A similar leakage problem may be created where the spindles, which support the rotatable shafts, are secured to the frame. The spindles are typically disposed within the wheel case such that the shaft bearings are exposed to a constant supply of lubricating oil. Each spindle includes a mounting flange, and an O-ring seal may be provided under the mounting flange. However, the cap screws used to secure the spindle to the frame may loosen in a manner similar to the problem described above, leading to similar problems.
As mentioned above, at least one of the shafts is operatively coupled to an external drive system. Typically, one of the shafts is extended through the wheel case cover for connection to a drive motor. This penetration through the wheel case must be sealed. Due to deflections at the end of the shaft caused by the extreme operating conditions, the end of the shaft typically experiences “runout” which typically causes premature breakdown of the seal. Although labyrinth seals have been employed, a typical labyrinth seal includes a weep hole for captured oil to escape back into the sealed area. Under the extreme operating conditions of the wheel case, in which the rotating eccentric weights contact the oil supply at velocities in excess of 5000 feet per second, the resulting oil agitation throws oil through the weep hole, causing lubricant loss. Consequently, the seal becomes one additional path of lubricant loss or contaminant ingress.
Accordingly, an improved wheel case having an improved fastening system less prone to loosening and leakage is desired. It is also desired to have an improved wheel case which exhibits better lubricant retention characteristics than prior art wheel cases.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary schematic elevational view of a vibratory device having a three shaft sealed wheel case attached to the vibratory device, the wheel case being shown with a portion cut away to reveal the wheels disposed therein;
FIG. 2 is an enlarged fragmentary cross-sectional view taken along line 2 — 2 of FIG. 1 and illustrating a wheel case constructed in accordance with certain teachings of the present invention;
FIG. 3 is a further enlarged fragmentary cross-sectional view of a sealed attachment bolt assembled in accordance with the teachings of the present invention;
FIG. 4 is a fragmentary cross sectional view of another sealed attachment bolt constructed in accordance with the teachings of the present invention;
FIG. 5 is a fragmentary cross sectional view of another sealed attachment bolt constructed in accordance with the teachings of the present invention;
FIG. 6 is a fragmentary cross sectional view of another sealed attachment bolt constructed in accordance with the teachings of the present invention;
FIG. 7 is a fragmentary cross sectional view of another sealed attachment bolt constructed in accordance with the teachings of the present invention;
FIG. 8 is a fragmentary cross sectional view of another sealed attachment bolt constructed in accordance with the teachings of the present invention;
FIG. 9 is an enlarged elevational view of a clipped washer for use with the attachment bolt of FIG. 8 ; and
FIG. 10 is an enlarged fragmentary view similar to FIG. 2 but illustrating a seal around the penetration of the shaft through the wheel case housing constructed in accordance with the teachings of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The embodiment described herein is not intended to be exhaustive or to limit the scope of the invention to the precise form disclosed. The following embodiment has been chosen and described in order to best explain the principles of the invention and to enable others skilled in the art to follow its teachings.
Referring now to the drawings, an improved wheel case generally indicated by the reference numeral 10 is shown in FIGS. 1 and 2 in a preferred environment of use, namely, mounted on a vibrating screen device 12 of the type commonly employed in the art to process aggregate materials by classifying and/or separating the aggregate material according to size. Persons of ordinary skill in the art will recognize that the improved wheel case 10 may also be used on other devices, such as vibrating trough feeders, as well as other devices benefitting from the features to be discussed below.
As shown in FIGS. 1 and 2 , the vibrating screen device 12 typically includes a frame 14 supporting a deck 16 to which is mounted one or more classifying screens (not shown) of the type commonly employed for such purposes. A pair of opposing sidewalls 18 are secured to the frame 14 , and one or more shafts 20 , each housed in a housing 22 , are rotatably mounted to the frame 14 and extend between the sidewalls 18 .
As shown in FIGS. 1 and 2 , one or more shafts 20 are provided, for example shafts 20 a , 20 b , and 20 c . It will be understood that only a single shaft 20 will be discussed in detail. The shaft 20 includes an end 24 which is rotatably mounted to a spindle 26 by a bearing assembly 28 . Attached to the end of the shaft 20 is wheel 29 having an eccentric weight 30 and a gear 32 , which gear 32 may be either a drive gear or a driven gear as required. Although only one end 24 of the shaft 20 it is shown, it will be understood that the other end (not shown) of the shaft 20 is substantially similar and is rotatably mounted to the opposing sidewall 18 of the frame 14 in a similar manner. The device 12 may also include a plurality of additional side members or stiffeners 34 as required.
As shown in FIG. 2 , the end 24 of the shaft 20 , along with the spindle 26 , the bearing assembly 28 , the eccentric weight 30 and the gear 32 are all disposed within the wheel case 10 . It will be understood that the wheel case 10 is adapted to contain therein a quantity of lubricating oil for the purposes of supplying lubricant to the bearing assembly 28 , the gear 32 , and to any other components housed within the wheel case 10 as required. It will also be understood that a portion of the eccentric weight 30 and/or a portion of the gear 32 comes into contact with, agitates, and distributes the oil about an interior 36 of the wheel case 10 .
As shown in FIGS. 1 and 2 , the wheel case 10 includes a housing 38 having a base 40 , a peripheral sidewall 42 extending outwardly away from the base 40 , and a cover 44 attachable to the sidewalls 42 so as to enclose the interior 36 . The cover 44 is preferably removable as would be known to those of skill in the art in order to gain access to the various components housed within the wheel case 10 . A plurality of attachment bolts 46 are provided for securing the wheel case 10 to the frame 14 (i.e., by securing the base 40 of the housing 38 to the sidewall 18 and the frame 14 ).
Although a number of configurations are contemplated for the attachment bolt 46 , the preferred embodiment is shown in FIG. 3 . Referring now to FIG. 3 , the attachment bolt 46 shown therein includes an inner end 48 disposed inside the housing 38 of the wheel case 10 , an outer end 50 disposed outside the housing 38 , and an interconnecting shank 52 . The inner end 48 includes an inner contact surface 54 , while the outer end 50 includes an outer contact surface 56 .
The bolt 46 is preferably a threadless bolt having a pressed on collar 58 , and preferably the bolt 46 is a threadless bolt sold under the trade name Huckbolt® and is manufactured by the Federal Mogul Corporation. Other suitable fasteners, especially other suitable threadless fasteners and/or other suitable fasteners which may be fastened with a desired pre-load tension on the bolt 46 may be employed, with the desired pre-load tension typically being designated by the manufacturer or otherwise determined using well known principles of mechanics. The collar 58 is preferably pressed on using a tool, such as a hydraulic tool, of the type commonly employed for such installations. The collar 58 is retained on the shank 52 by a plurality of annular rings 60 spaced along a portion of the shank 52 .
A pair of compression control washers 62 , 64 are provided. The washers 62 , 64 are preferably 0.108 inches thick, and have a hardness in the range of 38-45 on the Rockwell “C” hardness scale. The washer 62 includes an aperture 66 which is greater than the diameter of the shank 52 so as to define an annular cavity 68 surrounding the shank 52 . The annular cavity 68 is sized to receive a resilient O-ring seal 70 . Similarly, the washer 64 includes an aperture 72 which is greater than the diameter of the shank 52 so as to define an annular cavity 74 surrounding the shank 52 . The annular cavity 74 is sized to receive a resilient O-ring seal 76 . The O-rings 70 , 76 are preferably thicker than the thickness of the washers 62 , 64 , and are preferably 0.140 inches thick. Still preferably, the O-rings may be manufactured of a resilient rubber compound, such as nitrile rubber.
The washer 62 and the O-ring 70 are disposed adjacent the outer contact surface 56 , while the washer 64 and the O-ring 76 are disposed adjacent the inside contact surface 54 , inside the wheel case 10 . An additional washer 78 may be employed, but the use of such is optional.
In operation, the housing 38 and the stiffeners 34 are positioned for attachment to the sidewall 18 of the frame 14 as shown in FIG. 3 . The washer 62 and the O-ring 70 are positioned on the bolt 46 adjacent the outer contact surface 56 . The inner end 48 of the attachment bolt 46 is then inserted into the wheel case 10 from the opposite side of the sidewall 18 . The washer 64 and the O-ring 76 are placed along the shank 52 , and then the collar 58 is applied using the above-referenced tool in a known manner. The tool draws the inner end 48 (typically by pulling on a break-away portion, which is not shown but which is releasable along a frangible connection line 80 ). As stated above, the optional washer 78 may be included as shown.
In the process of securing the bolt 46 , the inner and outer contact surfaces 54 , 56 are drawn together, which compresses the O-rings 70 , 76 such that they substantially fill their respective annular cavities 68 , 74 . The ratio between the thickness of the O-rings 70 , 76 and the thickness of their associated washer 62 , 64 , allows for the O-rings to be compressed a desired amount to maximize their sealing capacities while preventing inadvertent damage to the O-rings via over-compression.
The embodiment shown in FIG. 4 is similar to that shown in FIG. 3 , but it excludes the inner washer 64 and the inner O-ring 76 , and excludes the optional washer 78 .
The embodiment shown in FIG. 5 also is similar to that shown in FIG. 3 , but it excludes the outer washer 62 and the outer O-ring 70 , and includes the optional washer 78 .
The embodiment shown in FIG. 6 is similar to that shown in FIG. 5 , but the inner washer 64 is sized such that the inner O-ring 76 is disposed in an annular cavity 65 defined in part by an outer perimeter 67 of the washer 64 . The embodiment of FIG. 6 also includes an optional washer 78 .
The embodiment shown in FIG. 7 is similar to that shown in FIG. 6 , but includes an outer washer 62 sized such that the outer O-ring 70 is disposed in an annular cavity 69 defined in part by an outer perimeter 71 of the washer 62 . The optional washer 78 is excluded.
Referring now to FIGS. 8 and 9 , an attachment bolt 146 is shown, such as an attachment bolt used to secure the spindle 26 to the frame 14 in an area of low lateral clearance. The bolt 146 is preferably a conventional cap screw, although other suitable fasteners may be employed. The bolt 146 includes an inner washer 164 having an aperture 172 defining with the bolt shank 152 an annular cavity 174 . A pair of compressible O-rings 176 a , 176 b are provided for insertion in the cavity 174 in stacked arrangement. The O-rings 176 a , 176 b will preferably have a stacked height totaling approximately 30% greater than the thickness of the washer 164 . It will be noted in FIG. 9 , that the washer 164 includes a truncated side portion 180 , thereby permitting an inner end 150 of the attachment bolt 146 to be positioned in close proximity to an extended portion 182 of the spindle 26 , such that upon application of a torque to an outer end 148 , rotation of the bolt 146 is prevented. The O-rings 176 a , 176 b cooperate to prevent lubricant from leaking out of the wheel case 10 along the shank 152 of the bolt 146 .
Referring now to FIG. 10 , it will be appreciated that at least one of the shafts 20 , such as, for example, the shaft 20 b , will include a portion 100 extending out of the cover 44 of the wheel case 10 for operative engagement with an external drive source (not shown). Accordingly, the cover 44 includes an aperture 102 having a seal 104 . Preferably, the seal 104 is a labyrinth seal, such as a ProTech® labyrinth seal manufactured by J M Clipper. The seal 104 includes at least one weep hole 106 . An annular cylindrical baffle 108 is secured to an inner surface 109 of the cover 44 , and is spaced outwardly from and generally surrounds the aperture 102 and the seal 104 . It will be noted that the baffle 108 includes an inner end 110 which is disposed generally adjacent to the wheel 29 so as to define a relatively small and generally annular gap 112 therebetween.
It will be appreciated that, during operation of the device 12 , splashing and otherwise agitated oil (not shown) is shielded from the seal 104 , the weep hole 106 and the aperture 102 by the annular baffle 108 . The sealing properties are enhanced by the relatively small size of the gap 112 .
Numerous modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure may be varied substantially without departing from the spirit of the invention, and the exclusive use of all modifications which come within the scope of the appended claims is reserved. | 4y
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to an automatic conveyorized solder mask vacuum applicator and method of operation thereof having utility in the application of dry films which conform to the contours of irregular surfaces such as the surfaces of printed circuit boards or other substrates having raised, typically electrically conductive, traces thereon. The applicator and method have particular utility for conveying and for applying heat and vacuum and mechanical pressure to printed circuit boards or substrates that prior to such application have had dry film loosely applied to at least one of the surfaces thereof as discrete cut sheets within the confines of the printed circuit board.
2. Description of the Prior Art
A solder mask is a hard, permanent layer of non-conductive material which covers the surface of a printed circuit board or other substrate, encapsulating the traces of the printed circuit itself. By solder mask is meant herein a hard, permanent layer which meets at least the minimal requirements of the abrasion resistance tests as defined in IPC-SM-840A, Table 12, Summary of Criteria for Qualification/Conformance (Institute for Interconnecting and Packaging Electronic Circuits). The solder mask is patterned to fully cover the circuitry, except for those portions intended to be exposed, e.g., for soldering to another component. Solder masks are typically formed from a layer of photoimageable composition which is applied to a surface of the printed circuit board. The photoimageable layer is exposed to actinic radiation which is patterned by means of a template or artwork. Subsequent to exposure, the photoimageable layer is developed in an organic solvent or an aqueous solution which washes away either exposed or unexposed portions of the layer (depending upon whether the photoimageable material is positive acting or negative acting). The portion of the layer which remains on the surface is then cured, e.g., with heat and/or UV light, to form a hard, permanent solder mask intended to protect the printed circuitry for the life of the board.
One prior art method of applying the layer of photoimageable composition to the circuit board surface is to apply the material in liquid form, and then, either allow it to dry or partially cure the material to form a semi-stable layer.
There are a number of advantages to applying a photoimageable layer to a circuit board as a dry film rather than as a liquid. In particular, dry films are free of organic solvent and therefore eliminate this hazard from the workplace and eliminate the need for apparatus to protect the immediate work environment and the more general environment from organic solvent emissions. Typically, a dry film comprises a cover sheet of support material which is somewhat flexible but which has sufficient rigidity to provide structure to a layer of photoimageable composition which overlies one surface of the cover sheet. The cover sheet may be formed of polyester material, such a polyethylene terephthalate (PET), such as that sold as MELINEX®.
To protect the photoimageable layer and to enable the dry film to be rolled, it is conventional for the exposed surface of the photoimageable layer to be covered with a removable protective sheet, e.g., a sheet of polyethylene. An example of such a dry film is sold as LAMINAR DM® by Morton International, Inc.
The method of use of such prior art dry film is generally as follows. The protective sheet is removed from the photoimageable composition layer immediately prior to application of the dry film to the surface of the printed circuit board. This may be accomplished, for example, using automated apparatus which peels away and rolls up the protective sheet as the dry film is unrolled from a reel. The dry film is applied to the surface of the circuit board with the photoimageable layer in direct contact with the board surface. Using heat, vacuum and mechanical pressure, the photoimageable layer is immediately laminated to the surface of the board. The cover sheet remains overlying the photoimageable layer, protecting the photoimageable layer from exposure to oxygen and from handling damage. The cover sheet also permits a pattern (or template) to be laid directly on top of the dry film for contact printing, if contact printing is to be used (as is usually preferred from the standpoint of obtaining optimal image resolution). The dry film is exposed to patterned actinic radiation through the PET cover sheet. At this time, the PET cover sheet is removed, permitting access to the exposed photoimageable layer by developer. Depending upon the composition of the photoimageable layer, the photoimageable layer is developed with organic solvent, aqueous developer, or semi-aqueous developer. By semi-aqueous developer is meant herein a developer which is about 90% or more by volume aqueous solution with the balance being an organic solvent such as 2-butoxy ethanol and other glycol ethers. The photoimageable layer may either be positive acting, in which case the exposed portions are removed by developer, or negative acting, in which case the unexposed portions are removed by developer. Most photoimageable layers for preparing solder masks are negative acting. Most photoimageable composition layers require some cure subsequent to development to render the layer hard and permanent so as to serve as a solder mask. Depending upon the composition of the photoimageable layer, curing may be effected with heat and/or UV light.
Printed circuit boards almost invariably have uneven surfaces in which circuitry traces are raised or elevated over the surface of a board of electrically non-conducting material. Circuitry traces may be the residual portions of an etched metal layer or may be built up from the board surface. It is desirable that a solder mask, particularly one formed from a photoimageable composition, conform to the contours of a circuit board surface. A conforming solder mask which adequately covers both the board surface and the upstanding traces minimizes the use of expensive photoimageable composition.
Processes for applying conforming solder mask on a surface having raised areas such as circuit traces on a printed circuit board are disclosed in U.S. Pat. Nos. 4,889,790 Leo Roos et al. and 4,992,354 F. J. Axon et al. and in for U.S. patent application Ser. No. 480,487 filed Feb. 14, 1990. These patents and application are assigned to the assignee of the present invention. The disclosures thereof, by reference, are incorporated herein.
The processes disclosed in these patents and application involve applying a solder mask-forming photoimageable composition layer to a printed circuit board using a dry film in which an intermediate layer is interposed between a support film or cover sheet and the photoimageable layer. The intermediate layer of the dry film is selectively more adherent to the photoimageable composition layer than to the cover sheet, allowing the cover sheet to be removed after the photoimageable layer is applied to a printed circuit board with the intermediate layer remaining on the photoimageable composition layer as a "top coat." The top coat is of non-tacky material and can be placed in contact with other surfaces, such as artwork for contact printing. The top coat also serves as an oxygen barrier, allowing the photoimageable composition layer to remain unexposed on the printed circuit board, after cover sheet removal, for some length of time. The use of dry film having the "intermediate layer" or "top coat" make possible the processes described in these patents and application. In each case there is provided a conforming step, e.g., conforming vacuum lamination, after removal of the cover sheet. Because the cover sheet is removed prior to the conforming step, better conformance, particularly when applying thin photoimageable composition layers onto boards with closely spaced traces, is achieved. Better resolution is also achievable because the top coat may be directly contacted with artwork for contact printing and because the top coat is much thinner than a cover sheet or support film and is, therefore, much less a deterrent to good resolution than a support film.
To form a solder mask, the protective, removable sheet of the dry film is first peeled away and the exposed surface of the photoimageable composition layer is applied to the surface of the printed circuit board. Using heat, vacuum and mechanical pressure, the dry film is laminated to the surface of the printed circuit board, partially conforming the photoimageable layer thereto. Within about 60 seconds and before substantial cooling of the printed circuit board and dry film has occurred, the cover sheet of the dry film is removed, whereupon the photoimageable composition layer and overlying top coat fully conform to the contours of the printed circuit board and substantially encapsulate the traces. The photoimageable composition layer is then exposed to patterned actinic radiation through the top coat. A developer is used to remove either exposed or non-exposed portions of the photoimageable composition layer, leaving the remaining portion of the layer laminated to the circuit board. Subsequently, the portions of the photoimageable composition layer remaining on the circuit board are cured, e.g., with heat and/or UV light.
In U.S. Pat. No. 4,946,524 granted on Aug. 7, 1990 to Robert C. Stumpf et al., the disclosure of which patent, by reference, is incorporated herein, there is disclosed an applicator and process for applying dry film solder mask material to the surface of a printed circuit board allowing, at the same time, handling of the board with the applied film, the draw-off of the air enclosed between the film and the board, and the removal of the cover sheet. The draw-off of air enclosed between the dry film and the surface of the printed circuit board is facilitated when, before vacuum lamination, the surface of the board is covered with a loose sheet of film. To that end the applicator of U.S. Pat. No. 4,946,524 is operative to tack the dry film to a board at the leading and trailing edges with the intermediate portion of the film loosely applied thereto. The film is tacked to the board as a discrete cut sheet within the confines of the perimeter of the surface of the board. For convenience, a printed circuit board having such loose application of a dry film sheet to the surface or surfaces thereof is referred to hereinafter as being "prelaminated."
The results of the processes described above have been most encouraging. Difficulty has been encountered, however, in attempting to adapt these processes for continuous automatic operation in an in-line system. This is particularly true with respect to the utilization of existing vacuum laminating apparatus in an in-line process. The present invention was devised to fill the gap that has existed in the art in this respect.
SUMMARY OF THE INVENTION
An object of the invention is to provide an improved method of and apparatus for applying heat, vacuum and mechanical pressure to prelaminated printed circuit boards and substrates, thereby to remove all of the air between the dry film and the surface of the printed circuit board or substrate to assure complete conformance of the dry film around the circuit traces and the substrate surface contours.
Another object of the invention is to provide a method of laminating a prelaminated board comprising the steps of:
(a) placing the board on the entrance end of a moving belt conveyor for movement into a vacuum laminator having an upper platen and a lower platen, which belt conveyor has an endless belt under tension that has an aperture therein and is characterized in having an initial or set-point position such that as the board is moved on the endless belt into the region of the vacuum chamber of the vacuum laminator the aperture is moved into alignment with and between the board and the lower platen;
(b) sensing by proximity switch means having a member movable with the endless belt the positioning of the board in the vacuum chamber of the vacuum laminator and stopping the movement of the belt conveyor;
(c) relieving the tension on the endless belt;
(d) lifting the lower platen up through the aperture in the endless belt into sealing engagement with the upper platen and thereby capturing within the vacuum chamber of the vacuum laminator the board and the portion at least of the endless belt upon which the board is positioned; and
(e) evacuating the vacuum chamber of the vacuum laminator.
Still another object of the invention is to provide a conveyorized dry film solder mask applicator that is characterized by the capacity thereof for continuous operation and the provision of a conveyor belt for conveying prelaminated printed circuit boards or substrates into and out of the vacuum chamber of a vacuum laminator.
A further object of the invention is to provide such a continuously operative conveyorized vacuum applicator that is operative, in association with first and second input rolls conveyors for feeding prelaminated printed circuit boards or substrates to the conveyor belt, in such a way as to allow one or more boards or substrates to be in the vacuum chamber of the vacuum laminator being vacuum laminated while the next boards or substrates to be vacuum laminated are arriving on the input rolls conveyors ready for the next vacuum lamination cycle of operation.
In accomplishing these and other objectives of the invention there is provided an apparatus for applying a conforming mask of dry film to a printed circuit board that operates automatically and includes a conveyor belt for carrying printed circuit boards into and out of the vacuum chamber of a vacuum laminator. The conveyor belt may be made of very thin (0.2 mm.) silicon rubber impregnated fiberglass cloth. This is to assure that the vacuum chamber of the vacuum laminator may be completely sealed when a vacuum is drawn.
The automatic conveyorized vacuum applicator may be operated to control the movement of the conveyor belt in a way to have one or more printed circuit boards in position in the vacuum chamber of the laminator at the same time with the next printed circuit boards staged in position on first and second input rolls conveyors for the next vacuum lamination cycle. Upon completion of the vacuum lamination cycle, the printed circuit boards are automatically conveyed out of the vacuum chamber and the staged new printed circuit boards to be vacuum laminated are conveyed into the vacuum chamber.
Upper and lower platens comprising the vacuum laminator are heated with the temperature thereof being monitored by suitable temperature measuring means that measure the temperature of the processed boards as they exit the vacuum chamber.
When the heated platens close and seal, vacuum is drawn to reduce the air pressure within the chamber thereby to draw air from between the loosely applied dry film and the surface or surfaces of the printed circuit board. At the end of the vacuum cycle, atmospheric air is allowed to enter the vacuum laminator and mechanical slap down pressure is applied by a movable air impervious resilient silicone blanket that is provided in association with the upper platen in the vacuum chamber.
The automatic conveyorized vacuum applicator has particular utility in conveying printed circuit boards and applying heat, vacuum and mechanical pressure to printed circuit boards that have been prelaminated with solder mask dry film fabricated in accordance with the processes described in the above identified U.S. patents and application and as disclosed in the aforementioned U.S. Pat. No. 4,946,524.
The conveyorized dry film solder mask applicator of the invention is an important component in the total arrangement of an automatic continuous flow of material in in-line processing of dry solder mask film and other films requiring vacuum lamination during processing.
The invention provides the means to automate the vacuum application process as an in-line system.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
With this description of the invention, a detailed description follows with reference being made to the accompanying figures of drawing which form part of the specification in which like parts are designated by the same reference numbers and of which:
FIG. 1 is a side view of a cabinet structure in which the conveyorized vacuum applicator of the present invention is housed;
FIG. 2 is a diagrammatic perspective view on a scale larger than that of FIG. 1 illustrating the conveyor system of the conveyorized vacuum applicator for sequentially feeding prelaminated printed circuit boards or substrates through the vacuum laminator;
FIGS. 3-13 and 18 are fragmented detail views which illustrate various features of the applicator of FIGS. 1 and 2;
FIGS. 14-17 are cross sectional views of a vacuum laminator that advantageously may be used with the conveyorized vacuum applicator and which illustrate a platen operation sequence thereof;
FIGS. 19-27 are diagrammatic perspective views on a smaller scale than shown in FIG. 2 that illustrate the function cycle of the conveyorized vacuum applicator when employed to feed printed circuit boards or substrates one at a time through the vacuum laminator; and
FIGS. 28-36 are diagrammatic perspective views that are similar to those of FIGS. 19-27, which illustrate the function cycle of the conveyorized vacuum applicator when employed sequentially to feed printed circuit boards or substrates two at a time through the vacuum applicator.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The conveyorized vacuum applicator according to the present invention has particular utility in the vacuum lamination of printed circuit boards and substrates of varying thicknesses and sizes, typically in a range from between 0.030 and 0.125 inches (0.08 and 0.32 cm.) and in a range from between 10×15 and 24×28 inches (25×150 and 60.96×71.12 cm.), which boards or substrates have been prelaminated with a loose sheet of dry film solder mask, as hereinbefore described. The specific function of the conveyorized vacuum applicator is to automatically apply a combination of heat, vacuum and mechanical pressure to completely remove all of the air between the dry film and the surface of the board or substrate to assure positive conformance of the dry film around etched circuit traces.
Referring to FIGS. 1 and 2 there is shown a support structure or frame 10 on which is mounted the conveyorized vacuum applicator, designated 12, according to the invention. The conveyorized vacuum applicator 12 is comprised of two parts. One part comprises first and second input conveyors 14 and 16, respectively. The other part comprises a vacuum section 18 which includes a 3/4 belt conveyor 20 and a vacuum laminator 22.
As shown in FIG. 2, the input conveyors 14 and 16 and the 3/4 belt conveyor 20 extend in end-to-end relation, in that order, from an entrance end 24 of input conveyor 14, from the entrance end 25 of the input conveyor 16 to the exit end 25a thereof and from an entrance end 26 of the belt conveyor 29 to and exit end 26a thereof.
Each of the first and second input conveyors 14 and 16 comprise a plurality of chain coupled rolls 15 and 17, respectively, which rolls 15 and 17 extend for a substantial distance across the width of the applicator 12. Positioned for vertical movement between the input conveyors 14 and 16, as shown in FIGS. 1 and 2, is a first adjustable barrier 28. Similarly positioned for vertical movement between the exit end of the second input conveyor 16 and the entrance end 25 of the 3/4 belt conveyor 20 is a second adjustable barrier 30.
Each of the first and second barriers 28 and 30 extend across the width of the applicator 12 and is movable upwardly by an individually associated air cylinder 32 and 34, respectively, as shown in FIGS. 2 and 3. Such movement is from a "down" or non-blocking position to an "up" position to block the transport to the next succeeding conveyor 16 or 20, respectively, of a printed circuit board being transported on the input conveyors 14 and 16 from preceding equipment indicated at 36.
As seen in FIGS. 2 and 4, photocells 38 and 40 are provided for sensing the approach of a printed circuit board to the exit ends of the input conveyors 14 and 16, respectively, and for initiating the actuation of individually associated air cylinders 32 and 34 for effecting the movement of respectively associated barriers 28 and 30 between the printed circuit board non-blocking and blocking positions thereof.
The 3/4 belt conveyor 20 includes a pair of rolls, specifically an input roll 42 and an output roll 44, both of which rolls extend across the width of the applicator 12. Wound around the rolls 42 and 44 are a pair of spaced endless chains 46 and 48 with the spacing being such that one chain 46 is on one side of applicator 12 and the other chain 48 is on the other side thereof. Chain 46 meshes with a gear 47 provided on the end of input roll 42 and a gear 49 provided on the end of the output roll 44, as shown in FIG. 2. Similarly, chain 48 meshes with gears provided on the other ends of the input roll 42 and the output roll 44. Thus, as shown in FIG. 7 chain 48 meshes with a gear 53 on the end of the output roll 44.
Positioned between the chains 46 and 48 and securely attached thereto at each end by a suitable gripper 51, as illustrated in FIGS. 6 and 7, is a belt 50 that extends about three quarters of the distance around the loop formed by the chains 46 and 48. The gripper 51 at each end of the belt 50 includes a bar 51a that is securely attached at one end to the chain 46 and at the other end to the chain 48. Carried by bar 51a and securely attached thereto by suitable bolts or rivets are bar members 51b and 51c of shorter length between which the end of belt 50 is captured and retained. Thus, as best seen in FIG. 2, the belt 50 has an aperture or opening 84 therein for the full width thereof, the length of which aperture 84 is about a quarter of the distance around the loop of the belt 50 around the input roll 42 and the output roll 44.
The belt 50 may be made of very thin fiberglass reinforced rubber. A total thickness of the belt in the range of 0.005 to 0.010 inches (0.013 to 0.025 cm.) is desirable to ensure that there is a complete seal when drawing a vacuum in the vacuum laminator 22. This is for the reason that the upper run 50a of the belt 50 is captured between the upper and lower platens of the vacuum laminator 22 during the vacuum lamination process.
Motive power for driving the chain coupled rolls of the input conveyors 14 and 16 and the 3/4 belt conveyor 20 is provided by an electrical motor 52. Motor 52 may comprise a direct current electrical motor and is provided with separate drive gears 54 and 56 for driving the input conveyors 14 and 16 and the belt conveyor 20, respectively.
As shown in FIG. 2, motor 52 is coupled by gear 54 and chain drive gearing 58 to input conveyors 14 and 16. Selective or conjoint drive of the input conveyors 14 and 16 is provided by electromagnetic clutches 60 and 62. As best seen in FIG. 8, energization and deenergization of clutch 60 controls the rotation of the chain coupled rolls of the input conveyor 14. Similarly, energization and deenergization of clutch 62 controls the rotation of the chain coupled rolls of the input conveyor 16.
Motor 52 is coupled by gear 56 and chain drive gearing 66 and 68 to the drive shaft 70 of the output roll 44 of the 3/4 belt conveyor 20. An electromagnetic clutch 72 positioned between chain drive gearing 68 and 70 provides for the selective control of the operation of the 3/4 belt conveyor.
In accordance with the invention, the motor 52 is a variable speed motor, being selectively energizable from a source of direct current (not shown) through motor speed control potentiometers 74, 76 and 78 and a selector switch 79, as shown in FIG. 2, to drive the input conveyors 14 and 16 at a speed of about three (3) meters/minute (mts/min), to drive the input conveyors 14 and 16 and the 3/4 belt conveyor 20 at a speed of about nine (9) mts/min, and to drive the 3/4 belt conveyor 20 only at a speed of 30 mts/min, as further described hereinafter. The arrangement is such that the input conveyors 14 and 16 can be driven independently of each other and of the 3/4 belt conveyor 20. Similarly, the 3/4 belt conveyor can be driven independently of each the input conveyors 14 and 16. At no time, however, when driven at the same time, can the speeds of the conveyors 14, 16 and 20 be different.
For the purpose of enabling the tension of the 3/4 belt 50 of the 3/4 belt conveyor 20 to be relieved at a desired point in the vacuum process, as shown in FIGS. 2 and 5, a bearing 80 in which the shaft of the input roll 42 of the 3/4 belt conveyor 20 is mounted for rotation is arranged to be shifted a short distance toward and away from the vacuum laminator 22 by a two-position air cylinder 82.
For sensing when a prelaminated printed circuit board has been moved by the belt conveyor 20 to a proper position relative to the vacuum laminator 22 for the vacuum lamination process to proceed, there is provided, as best seen in FIGS. 2, 9 and 10, a cam 86 and a sensor 88 that is disposed in cooperative relation therewith. Cam 86 is mounted on and moves with the endless chain 46 around the loop of the belt conveyor 20. Sensor 88 is mounted in any suitable manner on the frame 10 of the applicator 12.
When the printed circuit board is in the proper position relative to the vacuum laminator 22 for the vacuum lamination process to proceed, the aperture 84 in the belt 50 of the belt conveyor 20 is positioned immediately, that is, vertically, below the vacuum laminator, as best seen in FIG. 2. This allows the lower platen 90 of the vacuum laminator to be lifted up through the aperture 84 in belt 50 into cooperative relation with the upper platen 92 of the vacuum laminator 22 for effecting the vacuum lamination of a printed circuit board then resting on the surface of the upper run 50a of the belt 50 within the confines of the vacuum laminator 22.
There is an initial position of the belt conveyor 20 such that upon the transfer of a printed circuit board to the belt 50 from the input conveyor 16, the printed circuit board will be moved within the laminating region of the vacuum laminator 22 while the aperture 84 of the belt 50 is moved to a position vertically below the laminator 22. For convenience, that initial position of belt 50 is herein referred to as the "set-point" position of the belt conveyor 20.
For sensing the set-point position of the belt conveyor 20, there is provided a cam 94 that is mounted on the endless chain 48 and a sensor 96 that may be mounted on the frame 10 of the applicator 12, as illustrated in FIGS. 2, 11 and 12.
In order to provide a signal anticipatory of the approach of the belt conveyor 20 to the set-point position thereby to enable relatively fast operation in the return of the belt conveyor 20 to the set-point position, there is also provided a cam 98 and a sensor 100 for slowing down the speed of the belt conveyor 20 to the set-point position, as illustrated in FIGS. 2, 11 and 12.
For detecting the presence of a processed printed circuit board or substrate at the exit end 26 of the belt conveyor 20, there is provided an output photocell 102, as shown in FIGS. 2 and 13.
Also, as shown on FIGS. 2 and 13, an infrared sensor 104 is provided for sensing the temperature of the processed printed circuit board or substrate as it is conveyed out of the laminator 22. The temperature of the processed printed circuit board or substrate, as sensed by sensor 104 and indicated or displayed by suitable means, facilitates control of the heating means in the vacuum laminator 22 thereby to preclude overheating thereof and possible damage to the printed circuit board or substrate being vacuum laminated.
Since the sheets of dry film applied to the prelaminated printed circuit boards being vacuum laminated have high flow characteristics in the temperature range of 30° C. to 100° C., the vacuum lamination process may be carried out within this range.
A vacuum laminator 22 that advantageously may be used in the conveyorized vacuum laminator 12 is illustrated in FIGS. 14, 15, 16 and 17. Referring to FIG. 14, the laminator 22 includes an upper stationary platen 106 and a lower movable platen 108. Associated with the upper platen 106 is a resilient silicon rubber blanket 110 that forms a ceiling for the vacuum chamber region indicated at 112 in FIGS. 14, 15 and 16. The lower platen 108 has a well 114 into which a prelaminated printed circuit board or substrate to be vacuum laminated is positioned on a silicon rubber insert 116 for vacuum lamination. Sealing means 118 in the form of an O-ring surrounding the circumference of the lower platen 108 is provided for hermetically sealing the well 114 for the evacuation of air therefrom by a vacuum pump 120 when the lower platen 108 is moved upward into contact with the upper platen 106. One or more shim inserts 122 may be provided, as shown in FIG. 14, to accommodate printed circuit boards of different thicknesses, that is, for adjusting the printed circuit boards to an optimum position in the well 114 for best vacuum lamination operation. Both platens 106 and 108 include heaters, specifically a heater 124 in the upper platen 106 and a heater 126 in the lower platen 108.
Printed circuit boards that have been prelaminated, that is, have had dry film solder mask previously loosely applied to one or both sides thereof, as described hereinbefore, are vacuum laminated in the vacuum laminator 22 in the following sequence:
(1) The board to be vacuum laminated is placed in the well 114 of the lower platen 108 on top of the silicon rubber insert 116. This is facilitated by relieving the tension on the belt 50 on the surface of which the board has been conveyed to the region of the vacuum chamber 112.
(2) The lower platen 108 is moved upward, as shown in FIG. 16, to seal, by means of the O-ring 118, the well 114 which together with the blanket 72 forms the vacuum chamber 112. Note that the belt 50 on which the board being vacuum laminated rests is also captured between the upper platen 106 and the lower platen 108.
(3) The vacuum process cycle is started by the energization of the vacuum pump 120 thereby to evacuate air from the vacuum chamber 112 and from the region between the upper platen 106 and the blanket 110.
(4) For a short period at the end of a first stage of the vacuum process, there is a second stage or "slap down" of the blanket 110 in the upper platen 106, as shown in FIG. 17. This is effected by opening channels 128 in the upper platen 106 to allow atmospheric air to enter the space between the blanket 110 and the upper platen 106. Such slap down applies mechanical pressure on the printed circuit board to force the heated solder mask film to conform around the raised electrical circuit conductors.
(5) When the cycle is complete, the vacuum in the vacuum chamber 112 is released by allowing atmospheric air to enter therein whereby the lower platen 108 may be moved downward out of contact with the upper platen 106.
It is noted that, in accord with the invention, the prelaminated boards to be vacuum laminated by the conveyorized vacuum applicator 12 will have been centered by preceding equipment in the in-line system, although, if desired, adjustable guides 130 may be provided for that purpose in association with the input conveyors 14 and 16, as illustrated in FIG. 8.
The function cycle of the conveyorized vacuum applicator 12 with one board at a time being vacuum laminated is illustrated by FIGS. 19-27.
In step 1 of the sequence, as shown in FIG. 19, a prelaminated circuit board 132 is shown arriving on the input conveyor 14 from preceding equipment running at a speed of 3 mts/min. The second barrier 30 is in the "up" board blocking position. The first barrier 28 is in the "down" position and allows the board 132 to be conveyed to the exit end 25a of the input conveyor 16.
In step 2 of the sequence, as shown in FIG. 20, the board 132 is stopped by the second barrier 30 and is moved into alignment therewith, that is, squared up with respect thereto. As noted hereinbefore, the board 132 already has been centered on the conveyors 14 and 16, having been centered by preceding equipment or by adjustable guides 130 associated with the conveyors 14 and 16. The conveyor 16 is stopped, as by actuation of electromagnetic clutch 62 as soon as the board 132 is sensed at the exit end 25a thereof by the photocell 40.
As controlled by a programmable logic controller (PLC) indicated schematically by the reference numeral 134 in FIG. 2, the second barrier 30 is actuated downwardly, by actuation of air cylinder 34 in step 3 of the sequence, as shown in FIG. 21, to release the board 132. Immediately thereafter the input conveyor 16 and the belt conveyor 20 are both started by appropriate energization of the direct current motor 52 for operation at a speed of 9 mts/min to load the board 132 onto the belt 50 on the belt conveyor 20 and thereby into vacuum chamber 112 of the vacuum laminator 22.
In step 4 of the sequence, as seen in FIG. 22, a cam 86 and cooperating sensor 88 provide a signal to stop the belt conveyor 20 and the input conveyor 16 when the board 132 is in the vacuum chamber 112 at a position directly vertically above the well 114 in the lower platen 108. The second barrier 30 is moved up by actuation of air cylinder 34 and the input roll 42 of the belt conveyor 20 is shifted by the actuation of the two-position air cylinder 82 in the direction of the vacuum chamber 112 in order to release the tension of the belt 50. The input conveyors 14 and 16 start to run at a speed of 3 mts/min. Being disengaged from the chain drive gearing 56 by the electromagnetic clutch 72, the belt conveyor 20 remains stationary.
As seen in FIG. 23, in step 5 of the sequence, the lower platen 108 of the vacuum laminator 22 is moved vertically upward by a pneumatic ram 136. The platen 108 passes upward through the aperture 84 in the belt 50, which aperture 84 is then in vertical alignment with the lower platen 108. Vacuum pump 120 is actuated for a predetermined time in a first stage of the vacuum process, after which, for a short period, a slap down action, as described in connection with FIG. 17, is applied. During the vacuum phase the board 132 is heated by the heaters 124 and 126 of the upper and lower platens 106 and 108, respectively. Meanwhile, a new prelaminated board 132a to be vacuum laminated has arrived on the input conveyor 14, and with the first barrier 28 then in the down position, is moved to and is stopped at the second barrier 30 which, as shown in FIG. 23, is in the up position.
Step 6 of the sequence is shown in FIG. 24. This is after the vacuum process has been completed. The vacuum in the vacuum chamber 112 is released by actuating a valve to allow the introduction of atmospheric air into the vacuum chamber 112. The lower platen 108 is then lowered by the hydraulic cylinder 136 down through the aperture 84 in the belt 50 of the belt conveyor 20. The new board 132a is aligned or squared up on the second barrier 30 and the input conveyor 16 is stopped.
In FIG. 25, which shows step 7 of the sequence, the input belt roll 42 is moved back toward the exit end 25a of input conveyor 16 by the two-position air cylinder 34 to restore the tension of the belt 50 of the belt conveyor 20. The new board 132a is waiting in aligned position at the second barrier 30 on the input conveyor 16.
As shown in FIG. 26, which shows step 8 of the sequence, the actuation of the electromagnetic clutches 60, 62 and 72 is such that the belt conveyor 20 only starts. The energization of the motor 52 as controlled by the PLC 134 is then such that the belt conveyor 20 starts at a speed of 9 mts/min to effect a rapid unloading of the vacuum laminated or processed board 132.
In step 9 of the sequence, shown in FIG. 27, as soon as the processed board 132 is completely off the belt 50, as sensed by the photocell 102, the speed of the belt conveyor 20 is increased to 30 mts/min in order to move the belt 50 quickly to the set point and to load a new board 132a that has been waiting at the entrance end 24 of input conveyor 14. A few centimeters before the set point is reached the speed of the belt conveyor 20 is slowed down to 3 mts/min and then the belt conveyor 20 is stopped precisely at the set point. The cycle restarts from step 2 illustrated in FIG. 20.
In FIGS. 28-36 there are shown diagrammatic perspective views that are similar to those of FIGS. 19-27 and which illustrate a second embodiment of the conveyorized vacuum laminator, according to the invention, that is operative sequentially to feed prelaminated printed circuit boards two at a time through the vacuum laminator.
The second embodiment of the conveyorized vacuum laminator, designated 12', consists essentially of the same parts as the conveyorized vacuum laminator 12 of the first embodiment illustrated in FIGS. 1-27 and differs primarily therefrom in the manner of the sequential operation of the parts and a requirement only for the vacuum chamber region 112 to be large enough to accommodate two boards 132 at the same time.
With respect to the function cycle of the vacuum laminator 12', in step 1, as shown in FIG. 28, a first prelaminated circuit board 132 having dry film loosely applied to the surfaces thereof is shown arriving from the prelaminator on the input conveyor 14 running at a speed of 3 mts/min. The second barrier 30 is up. The first barrier 28 is down.
In Step 2 of the function cycle, as shown in FIG. 29, the first board 132 stops at the second barrier 30 and is aligned. The first barrier 28 goes up. A second board 132a stops on the first barrier 28 and also is aligned. The input conveyor 14 stops as soon as the first photocell 38 senses the arrival at the first barrier 28 of the second board 132a.
As shown in FIG. 30, in step 3 of the sequence both of the barriers 28 and 30 go down and both the input conveyors 14 and 16 and the conveyor belt 20 start at a speed of 9 mts/min to load the two boards 132 and 132a into the vacuum chamber 112 of the laminator 22.
In step 4 of the sequence, as shown in FIG. 31, when the boards 132 and 132a are in the vacuum chamber 112, a signal from a cam 86 and sensor 88 causes the input conveyors 14 and 16 and the belt conveyor 20 to stop. The second barrier 30 goes up while the first barrier 28 remains down. The conveyor input belt roll 42 is moved in the direction of the vacuum chamber 112 in order to release the tension of belt 50. The input conveyors 14 and 16 start at a speed of 3 mts/min.
In step 5, as shown in FIG. 32, the lower vacuum platen 108 is actuated upwardly by the pneumatic cylinder 136 and passes up through the aperture 84 in the belt 50 to engage the upper platen 106. The vacuum pump 120 is actuated to evacuate the vacuum chamber 112 for a predetermined period in a first stage vacuum process, at the end of which process a slap down action is applied, as described hereinbefore. During the vacuum phase, the two boards 132 and 132a are heated by the platens 106 and 108. Two new prelaminated printed circuit boards 132b and 132c to be vacuum laminated are shown arriving on the input conveyors 14 and 16 and stop at the barriers 28 and 30, respectively.
As shown in FIG. 33, after the vacuum process step 5, the vacuum is released from the vacuum chamber 112 in step 6 following which the lower platen 108 is lowered down through the aperture 84 in belt 50. The two newly arrived boards 132b and 132c are aligned on the barriers 28 and 30, respectively, and the input conveyors 14 and 16 stop.
In step 7, as shown in FIG. 34, the input belt roll 42 is moved by the two-position air cylinders 82 back away from the vacuum chamber 112 to restore the tension of the belt 50. The new boards 132b and 132c are waiting on the input conveyors 16 and 14, respectively.
In step 8, as shown in FIG. 35, the belt 50 only starts to move at a speed of 9 mts/min to unload the two processed boards 132 and 132a from the vacuum laminator 22.
In step 9, as shown in FIG. 36, as soon as the two boards 132 and 132a are completely off the belt 50, the speed of the belt 50 of the conveyor belt 20 is increased to 30 mts/min in order quickly to move the belt 50 to the set-point for loading the new boards 132b and 132c on the belt 50, on the upper run thereof. A few centimeters before the set-point is reached the belt 50 is slowed down to 3 mts/min and then is stopped precisely at set-point. The cycle restarts from step 2.
The sensing switches comprising cam 86 and sensor 88, cam 94 and sensor 96, and cam 98 and sensor 100 may each be of the type known in the art as proximity switches, a non-contacting switch. More specifically, the cam may comprise a metallic object with the sensor, in each case, comprising an electronic device which is fixed in position and is responsive to the movement nearby of the metallic cam and is operative to generate an electrical siqnal in response to movement and hence sensing of the metallic object.
The programmable logic controller 134 utilized to control the sequential operation of the conveyorized vacuum applicator 12 for vacuum laminating one prelaminated board at a time or two prelaminated boards at a time may be a microprocessor controller of a type available commercially from Landis & Gyr. The controller 134 responds to the various signals produced by the photocells 38, 40 and 102 and by the proximity switch sensors 88, 96 and 100 to initiate, in concert with preprogrammed control data the several ensuing control functions including timing of the vacuum process laminating stages. These control functions include the actuation in the proper sequence of the air cylinders 32, 34 and 82, the pneumatic ram 136, and the electromagnetic clutches 60, 62 and 72, and the selector switch 79 for the motor speed control potentiometers 74, 76 and 78. For convenience of illustration, in FIG. 2 the control paths between the PLC 134 and the several control devices just mentioned have been shown in dotted lines. It will be understood that, although not shown, the dotted lines include, where necessary and appropriate, as well known to those skilled in the art, conversion devices such as electrically operated pneumatic valves to control the various air cylinders and the pneumatic ram, and electrical relay means to control the motor speed control selector switch 79.
The electrical circuit connections to the several input terminals (not shown) of the PLC 134 from the photocells 38, 40 and 102 and from the sensors 88, 96 and 100 have not been shown in order to avoid complication of the drawing since such circuitry is well known and understood by those skilled in the art.
With this description of the invention in detail, those skilled in the art will appreciate that modifications may be made in the invention without departing from the spirit thereof. Therefore, it is not intended that the scope of the invention be limited to the specific embodiments illustrated and described. Rather, it is intended that the scope of the invention be determined by the scope of the appended claims. | 4y
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of co-pending application Ser. No. 10/549,620 filed on Dec. 4, 2006, which is the 35 U.S.C. §371 national stage of International PCT/IB2004/050238 filed on Mar. 12, 2004, which claims priority to Austrian Application No. A 444/2003 filed on Mar. 20, 2003. The entire contents of each of the above-identified applications are hereby incorporated by reference. Any disclaimer that may have occurred during prosecution of the above referenced applications is hereby expressly disclaimed.
FIELD OF THE INVENTION
[0002] The invention relates to a device and a method for wet treating a flat plate-like substrate, such as semiconductor wafers, flat panel displays or compact discs. The device comprising a spin-chuck for holding and rotating the substrate, at least one dispenser for dispensing a liquid onto at least one surface of said substrate, a liquid collector circumferentially surrounding said spin-chuck for collecting liquid, which is spun off the substrate during rotation. The liquid collector has at least two collector levels. Each of the collector levels has the purpose of separately collecting liquids in different collectors.
[0003] The device further comprises lifting means for moving spin-chuck relative to liquid collector substantially along the rotation axis and at least two exhaust levels for separately collecting gas from the interior of the liquid collector. Collecting gas from the interior of the liquid collector is useful to avoid deposition of mist being generated when liquid is spun off the substrate.
BACKGROUND OF THE INVENTION
[0004] Such a liquid collector often is called a “cup” even though it does not necessarily have a closed bottom. Another word often used for the liquid collector is “chamber” even though it is not closed on all sides.
[0005] Such a device is known in the art and described in details in U.S. Pat. No. 4,903,717. This patent shows each collector of each collector level being connected to a common exhaust. Each collector level thereby simultaneously serves as an exhaust level. Therefore while the common exhaust is turned on gas is sucked from the interior of the liquid collector by each exhaust level.
[0006] During processing it might happen that below the level of the spin-chuck the gas pressure is lower than ambient gas pressure. Consequently liquid which is ought to be spun in to a specific collector level might be partly sucked into the collector level below the selected collector level.
[0007] If a liquid X is brought to a wrong collector level in which a different liquid Y shall be collected liquid X will contaminate liquid Y. In the worst case liquids X and Y react with one another generating hazardous or flammable reaction products.
[0008] Another undesired result might happen if liquid Y is recycled in order to treat as many substrates as possible. A contamination of liquid Y with liquid X then might result in the destruction of the substrates treated thereafter. In this case another consequence could be a significant decrease of the shelf life of liquid Y.
SUMMARY OF THE INVENTION
[0009] Thus it is an object of the invention to avoid liquid being partly sucked into the collector level not actually selected to collect that liquid.
[0010] Another object of the invention is to decrease the necessary exhaust flow. This is not only because a high exhaust volume per time unit raises process cost, but also because too high exhaust sucks too much liquid into the exhaust, which has the disadvantages of high liquid consumption and of high afford for cleaning the exhausted air.
[0011] The invention meets the objects by providing a device for wet treating a flat platelike substrate comprising:
[0000] a spin-chuck for holding and rotating the substrate; at least one dispenser for dispensing a liquid onto at least one surface of said substrate; a liquid collector circumferentially surrounding said spin-chuck for collecting liquid, which is spun off the substrate during rotation, with at least two collector levels, for separately collecting liquids in different collectors; lifting means for moving spin-chuck relative to liquid collector substantially along the rotation axis; at least two exhaust levels for separately collecting gas from the interior of the liquid collector; at least one exhaust influencing means, which is associated with at least one of said at least two exhaust levels, for selectively varying gas flow conditions in at least on of said at least two exhaust levels.
[0012] The dispenser can be configured in different ways, e.g. so that liquid sprays onto a substrate or runs onto the substrate in a continuous, turbulence-free way. The dispenser can be configured either to be directed towards the lower surface of a substrate when processed, therefore directed upwards, or towards the upper surface of a substrate when processed, therefore directed downwards. In both cases the dispenser can be configured to be horizontally moved during processing. It is further possible to use dispensers of both configurations, which allows to apply liquid onto both surfaces of the substrate even at the same time.
[0013] The spin-chuck can for instance be a vacuum-chuck, a Bernoulli-chuck, a chuck gripping the edge of the substrate only (edge contact only=EeG) or a combination of such types.
[0014] Each exhaust level comprises interiorly open suction orifices. The suction orifices may be an annularly arranged plurality of suction nozzles. Another possibility is to provide one annular slit-shaped nozzle. In any case it is advantageous to provide an annular gas-collecting chamber to circumferentially equalize gas flow conditions in one and the same exhaust level.
[0015] An advantage of the invention is that a significant reduction of the exhausted volume is possible and that cross-contamination between two neighboured collector levels can be avoided.
[0016] Optionally the device has exhaust influencing means, which are flow control modulating valve, such as a butterfly valve. This allows not only to shut off an exhaust level, but also to precisely lower gas flow in every exhaust level.
[0017] In an advantageous device the at least one exhaust influencing means is a closing valve, whereby one of the at least two exhaust levels can be closed. Such a configuration allows an easier control.
[0018] In another embodiment the device comprises controlling means whereby the at least one exhaust influencing means is controlled in dependence of the relative position of spin-chuck to liquid collector. Although this can be carried out easily in a mechanic way by connecting exhaust influencing means direct with the lifting means this will typically be done by a computer. In the latter case the computer receives information about the relative position of chuck to liquid collector either directly from the lifting means or electronic detectors detect the position.
[0019] If the suction orifices of at least one of the exhaust levels are connected to one of the two collector levels this collector level at the same time serves as exhaust level. The gas is sucked from the interior of the liquid collector into the collector level and therein separated from the liquid.
[0020] Yet another embodiment has at least one of the at least two exhaust levels arranged above or below of a collector level. In this case the collector level only collects liquid and does not suck gas as well. This brings the advantage that gas and liquid do not have to be separated after being collected.
[0021] Another aspect of the invention is a method of controlling the gas flow within a device for wet treating a flat plate-like substrate. The device comprises a spin-chuck for holding and rotating the substrate, at least one dispenser for dispensing a liquid onto at least one surface of said substrate, a liquid collector circumferentially surrounding said spin-chuck for collecting liquid, which is spun of the substrate during rotation. The liquid collector comprises at least two collector levels for separately collecting liquids. The device further comprises lifting means for moving spin-chuck relative to liquid collector substantially along the rotation axis and at least two exhaust levels for separately collecting gas from the interior of the liquid collector. The method is characterized in selectively generating different gas flow conditions in at least two of said exhaust levels.
[0022] In an embodiment the different gas flow conditions are selected in a way to achieve substantially the same gas pressure adjacent to the rotating substrate above and below
[0023] Further details and advantages of the invention can be realized from the detailed description of a preferred embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 shows a schematic cross section of a first embodiment of the invention.
[0025] FIG. 2 shows a schematic cross section of a second embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0026] FIG. 1 shows a device 1 comprising a spin-chuck 2 for holding and rotating a substrate W. The substrate has a first side WI and a second side W 2 . The spin-chuck is connected to a gear motor unit 5 to be rotated about its axis A. Dispense arm 3 is used for dispensing liquid onto the first surface WI of the substrate W.
[0027] A cup-like liquid collector 4 circumferentially surrounds the spin-chuck 2 . The liquid collector is mounted on a frame (not shown). Lifting means H are provided to alter the spin-chuck position relative to the liquid collector. Thus the spin-chuck can be lifted to each of the three collector levels L 1 , L 2 and L 3 . Each collector level L 1 , L 2 , L 3 comprises an annular duct 41 , 42 , 43 to have spun off liquid collected therein. An additional splash guard (not shown) can be used for each collector to allow spun off liquid to hit it at an acute angle and thereafter to be directed to the annular duct. Each annular duct 41 , 42 , 43 is connected to a pipe 81 , 82 , 83 through which the collected liquid is drained. Drained liquid can immediately be reused to be dispensed to the substrate or collected as waste liquid. Each collector level L 1 , L 2 , L 3 is for collecting different liquids. L 1 is for collecting rinse liquid (e.g. DI-water), L 2 for acidic liquids and L 3 for basic liquids.
[0028] The dash dotted lines indicate the planes, where the substrate is to be placed for spinning off the liquids into the different collector levels.
[0029] Above each collector level L 1 , L 2 , L 3 an exhaust level E 1 , E 2 , E 3 is arranged substantially parallel to the collector level. The exhaust levels are indicated by dotted lines. Each exhaust level comprises a plurality of interiorly open annularly arranged suction orifices 21 , 22 , 23 . Each array of the plurality of suction orifices 21 , 22 or 23 is connected to a separate ring-shaped gas-collecting chamber 11 , 12 , 13 respectively.
[0030] Each gas-collecting chamber is sucked off via a pipe 61 , 62 , 63 . In each pipe 61 , 62 , 63 is controlled by a valve 71 , 72 , 73 . In the shown embodiment the valves are butterfly valves. This gives the advantage that the valve does not have to be totally closed but can be almost closed so that still a very small amount of gas can be sucked off in that specific suction level.
[0031] Most of the gas flow (air) that is sucked from the interior 40 of the liquid collector is provided from above (first gas-flow F 1 ). Additional openings are provided, which connect the interior of the liquid collector below the chuck with the exterior. This results in a second gas-flow F 2 , which is preferably feed with clean air either from the surrounding clean room or from a separate source. Means for selectively modulating the second gas-flow can be provided.
[0032] The following table shows possible conditions for running the device 1 as shown in FIG. 1 :
[0000]
TABLE 1
Chuck Position
upper
middle
lower
exhaust
exhaust
exhaust
level E1
level E2
level E3
upper collector level L1
100% open
80% open
closed
(FIG. 1)
middle collector level L2
10% open
100% open
60% open
lower collector level L3
closed
10% open
100% open
[0033] A computer can automatically select the status of each exhaust level in dependence of the position of the chuck.
[0034] FIG. 2 shows a second embodiment of the invention similar to the first embodiment with the following differences. The exhaust orifices 21 , 22 , 23 are connected to the collector levels. Thus the collector levels L 1 , L 2 , L 3 serve at the same time as exhaust levels E 1 , E 2 , E 3 . To equalize suction conditions circumferentially around each exhaust level each array of suction orifices is connected to an annular gas-collector chamber.
[0035] The following table shows possible conditions for running the device 1 as shown in FIG. 2 :
[0000]
TABLE 2
Chuck Position
upper
middle
lower
exhaust
exhaust
exhaust
level E1
level E2
level E3
upper collector level L1
100% open
10% open
closed
(FIG. 1)
middle collector level L2
10% open
100% open
10% open
lower collector level L3
closed
10% open
100% open
[0036] In order to separate gas sucked from a specific exhaust level (e.g. E 2 ) from gas sucked by another exhaust level (e.g. E 3 ) it is possible to connect each exhaust level to a different exhaust system. Such an exhaust system may contain elements for neutralizing the gas, denoxing (removing NO) and/or removing liquid residues (mist).
[0037] When lowering the chuck 2 the gas volume 47 below the chuck 2 is reduced. Therefore to avoid discharging gas against the second gas flow F 2 might it be necessary to temporarily open the lower gas exhaust level or to generally increase exhaust flow E. | 4y
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BACKGROUND
[0001] 1. Field of the Invention
[0002] This invention relates to systems and methods for performing microfluidic assays. More specifically, the invention relates to systems and methods for controlling flow through a microchannel.
[0003] 2. Discussion of the Background
[0004] The detection of nucleic acids is central to medicine, forensic science, industrial processing, crop and animal breeding, and many other fields. The ability to detect disease conditions (e.g., cancer), infectious organisms (e.g., HIV), genetic lineage, genetic markers, and the like, is ubiquitous technology for disease diagnosis and prognosis, marker assisted selection, correct identification of crime scene features, the ability to propagate industrial organisms and many other techniques. Determination of the integrity of a nucleic acid of interest can be relevant to the pathology of an infection or cancer. One of the most powerful and basic technologies to detect small quantities of nucleic acids is to replicate some or all of a nucleic acid sequence many times, and then analyze the amplification products. Polymerase chain reaction (“PCR”) is perhaps the most well known of a number of different amplification techniques.
[0005] PCR is a powerful technique for amplifying short sections of DNA. With PCR, one can quickly produce millions of copies of DNA starting from a single template DNA molecule. PCR includes a three phase temperature cycle of denaturation of DNA into single strands, annealing of primers to the denatured strands, and extension of the primers by a thermostable DNA polymerase enzyme. This cycle is repeated so that there are enough copies to be detected and analyzed. In principle, each cycle of PCR could double the number of copies. In practice, the multiplication achieved after each cycle is always less than 2. Furthermore, as PCR cycling continues, the buildup of amplified DNA products eventually ceases as the concentrations of required reactants diminish. For general details concerning PCR, see Sambrook and Russell, Molecular Cloning—A Laboratory Manual (3rd Ed.), Vols. 1-3, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y. (2000); Current Protocols in Molecular Biology, F. M. Ausubel et al., eds., Current Protocols, a joint venture between Greene Publishing Associates, Inc. and John Wiley & Sons, Inc., (supplemented through 2005) and PCR Protocols A Guide to Methods and Applications, M. A. Innis et al., eds., Academic Press Inc. San Diego, Calif. (1990).
[0006] Real-time PCR refers to a growing set of techniques in which one measures the buildup of amplified DNA products as the reaction progresses, typically once per PCR cycle. Monitoring the accumulation of products over time allows one to determine the efficiency of the reaction, as well as to estimate the initial concentration of DNA template molecules. For general details concerning real-time PCR see Real-Time PCR: An Essential Guide, K. Edwards et al., eds., Horizon Bioscience, Norwich, U.K. (2004).
[0007] Several different real-time detection chemistries now exist to indicate the presence of amplified DNA. Most of these depend upon fluorescence indicators that change properties as a result of the PCR process. Among these detection chemistries are DNA binding dyes (such as SYBR® Green) that increase fluorescence efficiency upon binding to double stranded DNA. Other real-time detection chemistries utilize Foerster resonance energy transfer (FRET), a phenomenon by which the fluorescence efficiency of a dye is strongly dependent on its proximity to another light absorbing moiety or quencher. These dyes and quenchers are typically attached to a DNA sequence-specific probe or primer. Among the FRET-based detection chemistries are hydrolysis probes and conformation probes. Hydrolysis probes (such as the TaqMan® probe) use the polymerase enzyme to cleave a reporter dye molecule from a quencher dye molecule attached to an oligonucleotide probe. Conformation probes (such as molecular beacons) utilize a dye attached to an oligonucleotide, whose fluorescence emission changes upon the conformational change of the oligonucleotide hybridizing to the target DNA.
[0008] Commonly-assigned, co-pending U.S. application Ser. No. 11/505,358, entitled “Real-Time PCR in Micro-Channels,” the disclosure of which is hereby incorporated by reference, describes a process for performing PCR within discrete droplets flowing through a micro-channel and separated from one another by droplets of non-reacting fluids, such as buffer solution, known as flow markers.
[0009] Devices for performing in-line assays, such as PCR, within microchannels include microfluidic chips having one or more microchannels formed within the chip are known in the art. These chips utilize a sample sipper tube and open ports on the chip topside to receive and deliver reagents and sample material (e.g., DNA) to the microchannels within the chip. The chip platform is designed to receive reagents at the open ports—typically dispensed by a pipetter—on the chip top, and reagent flows from the open port into the microchannels, typically under the influence of a vacuum applied at an opposite end of each microchannel. The DNA sample is supplied to the microchannel from the ports of a micro-port plate via the sipper tube, which extends below the chip and through which sample material is drawn from the ports due to the vacuum applied to the microchannel.
[0010] In some applications, it is desirable that fluids from all of the top-side open ports flow into the microchannel, and, in other applications, it will be desirable that fluid flow from one or more, but less than all, of the top-side open ports. Also, to introduce different reagents into the microchannel via a sipper tube—typically extending down below the microchip—it is necessary to move the sipper tube from reagent container to reagent container in a sequence corresponding to the desired sequence for introducing the reagents into the microchannel. This requires that the processing instrument for performing in-line assays within the microfluidic channel of a microchip include means for effecting relative movement between the sipper tube and the different reagent containers. In addition, sipper tubes, which project laterally from a microchannel, are extremely fragile, thereby necessitating special handling, packaging, and shipping.
SUMMARY
[0011] Aspects of the invention are embodied in a method of controlling fluid flow within a microfluidic circuit including an inlet port through which fluid is introduced into the circuit, at least one microchannel for fluid flow in fluid communication with the inlet port, and an outlet port in fluid communication with the microchannel. The method comprises causing fluid flow from the inlet port into the microchannel by applying a first pressure to the outlet port and opening the inlet port to a second pressure higher than the first pressure, such as atmospheric pressure, and then stopping the fluid flow from the inlet port by closing the inlet port to the second pressure and applying the first pressure to the inlet port.
[0012] Further aspects of the invention are embodied in a system for controlling microfluidic flow. The system comprises a microfluidic circuit including at least one inlet port through which fluid is introduced into the circuit, at least one microchannel for microfluidic flow in fluid communication with the inlet port, and an outlet port in fluid communication with the microchannel. The system further includes at least one pressure source in communication with the outlet port and a valve mechanism operatively associated with each inlet port and in communication with the pressure source. The valve mechanism is adapted to selectively connect the inlet port (1) to a first pressure generated by the pressure source or (2) to a second pressure higher than the first pressure.
[0013] According to further aspects of the invention, the system includes a controller adapted to cause the pressure source to apply the first pressure to the outlet port and to cause the valve mechanism to open the inlet port to the second pressure to cause fluid to flow from the inlet port into the microchannel. After the inlet port has been open to the second pressure for a predetermined period of time, the controller causes the valve mechanism to close the inlet port to the second pressure and open the inlet port to the pressure source to stop flow from the inlet port into the microchannel.
[0014] Further aspects of the invention are embodied in a method for sequentially introducing predetermined amounts of different reaction fluids into a microchannel. The method comprises the steps of providing a microfluidic circuit including a microchannel, a plurality of inlet ports in fluid communication with the microchannel and through which different reaction fluids are introduced into the microchannel, and an outlet port in fluid communication with the microchannel. A negative pressure differential is applied to the outlet port, and a predetermined amount of reaction fluid is sequentially introduced into the microchannel from each of the inlet ports by sequentially opening each inlet port to higher pressure for a predetermined period of time while the other inlet ports are closed to cause a predetermined amount of fluid to flow from that inlet port into the microchannel, and, after the predetermined period of time, stopping fluid flow from that inlet port by closing that inlet port to the higher pressure and applying the negative pressure differential to that inlet port for period of time to equalize the pressure between the inlet port and the inlet of the microchannel, and then shutting off the valve to the inlet port.
[0015] The above and other aspects and embodiments of the present invention are described below with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various embodiments of the present invention. In the drawings, like reference numbers indicate identical or functionally similar elements.
[0017] FIG. 1 is a schematic view of a microfluidic chip and flow control system embodying aspects of the present invention.
[0018] FIG. 2 is a schematic view of an alternative embodiment of a microfluidic chip and flow control system embodying aspects of the present invention.
[0019] FIG. 3 is a schematic view of a second alternative embodiment of a microfluidic chip and flow control system embodying aspects of the present invention.
[0020] FIG. 4 is a flow chart illustrating steps of performing a sequential, multiplex assay within a micro channel in accordance with aspects of the present invention.
[0021] FIG. 5 shows time history profiles of the flows of DNA, polymerase, assay primers, and the resulting sample test stream within a microchannel.
[0022] FIG. 6 shows time history profiles of intermittent application of negative pressure and atmospheric pressure to a fluid input well of a microfluidic chip to achieve flow metering.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0023] As used herein, the words “a” and “an” mean “one or more.” Furthermore, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although any methods and materials similar or equivalent to those described herein can be used in the practice of the present invention, the preferred materials and methods are described herein.
[0024] A system for microfluidic flow embodying aspects of the present invention is shown in FIG. 1 . The system includes a microfluidic circuit which, in the illustrated embodiment, is carried on a microfluidic chip 10 . Microfluidic chip 10 includes inlet ports 12 , 14 , 16 , a microchannel 20 that is in fluid communication with the inlet ports 12 , 14 , 16 , and an outlet port 18 also in fluid communication with the microchannel 20 . The embodiment shown in FIG. 1 is exemplary; the microfluidic circuit may include more or less than three inlet ports and may include more than one microchannel in communication with some or all of the inlet ports. The microfluidic circuit may also include more than one outlet port. Fluid is introduced into the circuit through the fluid inlet ports 12 , 14 , and 16 . Fluid may be provided to the fluid inlet ports in any appropriate manner known in the art. Or, alternatively, fluid may be provided to the fluid inlet ports by means of a fluid-containing cartridge coupled to each port in a fluid-communicating manner as described in commonly assigned U.S. patent application Ser. No. 11/850,229 “Chip and cartridge design configuration for performing microfluidic assays”, the disclosure of which is hereby incorporated by reference.
[0025] The microfluidic chip 10 may be formed from glass, silica, quartz, or plastic or any other suitable material.
[0026] Fluid is collected from the microchannel 20 through the fluid outlet 18 and may be deposited in any appropriate waste reservoir, such as, for example, a chip as described in the commonly assigned U.S. patent application Ser. No. 11/850,229.
[0027] Fluid movement through the circuit is generated and controlled by means of a negative pressure differential applied between the outlet port 18 and one or more of the inlet ports 12 , 14 , 16 . Application of a negative pressure differential between the outlet port 18 and one or more of the inlet ports 12 , 14 , 16 will cause fluid flow from the inlet port(s), through the microchannel 20 and to the outlet port 18 . A pressure differential can be generated by one or more pressure sources, such as negative pressure source 22 , which, in one embodiment, may comprise a vacuum pump. In the illustrated embodiment, pressure differentials between the outlet port 18 and the inlet ports 12 , 14 , 16 is controlled by means of pressure control valves controlling pressure at each of the inlet ports 12 , 14 , 16 and the outlet port 18 .
[0028] More specifically, a pressure control valve 30 is arranged in communication with the pressure source 22 and the outlet port 18 . Similarly, a pressure control valve 24 is arranged in communication with the inlet port 12 , a pressure control valve 26 is arranged in communication with the inlet port 14 , and a pressure control valve 28 is arranged in communication with the inlet port 16 . Arrangements having more than three inlet ports would preferably have a pressure control valve associated with each inlet port. In the illustrated embodiment of FIG. 1 , valves 24 , 26 , 28 are three-way valves which may selectively connect each associated inlet port 12 , 14 , 16 , respectively, to either atmospheric pressure, represented by the circled letter “A”, or an alternative pressure source, which may be the negative pressure source 22 . That is, in the illustrated embodiment, valve 24 is in communication pressure source 22 via pressure line 32 and is in communication with inlet port 12 via pressure line 34 . Valve 26 is in communication with pressure source 22 via pressure line 36 and is in communication with inlet port 14 via pressure line 38 . Valve 28 is in communication with pressure source 22 via pressure line 40 and is in communication with inlet port 16 via pressure line 42 . Valve 30 is connected via pressure line 44 to the pressure source 22 and by pressure line 46 to outlet port 18 . In the illustrated embodiment, valve 30 is also a three-way valve for selectively connecting the outlet port 18 to either atmospheric pressure, indicated by the circled “A”, or to the pressure source 22 .
[0029] Pressure source 22 and valves 24 , 26 , 28 , 30 may be controlled by a controller 50 . Controller 50 is connected via a control line 52 to the pressure source 22 , via a control line 54 to the valve 24 , via a control line 56 to valve 26 , via a control line 58 to valve 28 , and via a control line 60 to valve 30 . Controller 50 may also be connected to one or more of the various components wirelessly or by other means known to persons of ordinary skill in the art. Controller 50 may comprise a programmed computer or other microprocessor.
[0030] As mentioned above, fluid flow from an inlet port 12 , 14 , and/or 16 through the microchannel 20 and to the outlet port 18 is generated by the application of a negative pressure differential between the outlet port 18 and one or more of the inlet ports. More specifically, to generate a fluid flow from inlet port 12 , a negative pressure is applied to the outlet port 18 by connecting the negative pressure source 22 to the outlet port 18 via the control valve 30 and pressure lines 44 and 46 . Inlet port 12 is opened to atmospheric pressure by valve 24 . This creates the negative pressure differential between the outlet port 18 and the inlet port 12 . Assuming that fluid flow from other inlet ports is not desired while fluid is flowing from the inlet port 12 , inlet port 14 is closed to atmospheric pressure by valve 26 and inlet port 16 is closed to atmospheric pressure by valve 28 . To stop fluid flow from the inlet port 12 , valve 24 is activated (e.g., via the controller 50 ) to close off the inlet port 12 to atmospheric pressure. To rapidly stop the flow of fluid from the inlet port 12 , it may be desirable to connect the inlet port 12 to the negative pressure source 22 via the control valve 24 for a period of time sufficient to equalize the pressure between the inlet port 12 and the inlet of the microchannel, and then shut off control valve 24 to maintain this pressure equilibrium.
[0031] A predetermined volume of fluid can be introduced into the microchannel 20 from any of the inlet ports 12 , 14 , and 16 —assuming the flow rate generated by the pressure differential between the outlet port 18 and the applicable inlet port is known—by maintaining the pressure differential for a period of time which, for the generated flow rate, will introduce the desired volume of fluid into the microchannel 20 . Maintaining the pressure differential can be effected by proper control of the pressure control valves associated with the inlet ports and the outlet port.
[0032] Activation and timing of the control valve 24 may be controlled by the controller 50 .
[0033] To then generate fluid flow from the inlet port 14 , valve 26 is activated (e.g., by controller 50 ) to open inlet port 14 to atmospheric pressure while negative pressure is applied to the outlet port 18 , thus creating the negative pressure differential between the outlet port 18 and the inlet port 14 . Fluid flow from the inlet port 14 is stopped by activating valve 26 to close inlet port 14 to atmospheric pressure, and, to rapidly stop flow from the inlet port 14 , valve 26 opens the inlet port 14 to the negative pressure source 22 for a period of time sufficient to equalize the pressure between the inlet of the microchannel and the inlet port 14 , and then shut off valve 26 to maintain this pressure equilibrium.
[0034] Similarly, to generate fluid flow from the inlet port 16 , valve 28 is activated (e.g., by controller 50 ) to open inlet port 16 to atmospheric pressure while negative pressure is applied to the outlet port 18 , thus creating the negative pressure differential between the outlet port 18 and the inlet port 16 . Fluid flow from the inlet port 16 is stopped by activating valve 28 to close inlet port 16 to atmospheric pressure, and, to rapidly stop flow from the inlet port 16 , valve 28 opens the inlet port 16 to the negative pressure source 22 for a period of time sufficient to equalize the pressure between the inlet of the microchannel and the inlet port 16 , and then shut off valve 28 .
[0035] FIGS. 2 and 3 show alternative arrangements for controlling the pressure differential between an outlet port and one or more of the inlet ports of a microfluidic circuit. FIG. 2 shows a system similar to that shown in FIG. 1 except that each inlet port 12 , 14 , 16 is coupled to two two-way valves as opposed to a single three-way valve. More specifically, inlet port 12 is coupled to a first two-way valve 24 a for selectively connecting the inlet port 12 to the pressure source 22 via pressure lines 32 and 62 . Inlet port 12 is also coupled to a second two-way valve 24 b for selectively connecting the inlet port 12 to atmospheric pressure “A” via pressure line 64 .
[0036] Similarly, inlet port 14 is coupled to a first two-way valve 26 a for selectively connecting port 14 to the pressure source 22 via pressure lines 36 and 66 and to a second two-way valve 26 b for selectively connecting the inlet port 14 to atmospheric pressure via pressure line 68 . Inlet port 16 is coupled to a first two-way valve 28 a for selectively connecting the inlet port 16 to the pressure source 22 via pressure lines 40 and 70 and to a second two-way valve 28 b for selectively connecting the inlet port 16 to atmospheric pressure via pressure line 72 .
[0037] In the system shown in FIG. 2 , outlet port 18 is coupled to two-way valve 76 for selectively connecting the outlet port 18 to the pressure source 22 via pressure lines 44 and 46 .
[0038] Controller 50 controls the negative pressure source 22 via control line 52 , controls two-way valve 76 via control line 60 , controls two-way valve 24 a via control line 72 , and controls two-way valve 24 b via control line 74 . Controller 50 is also linked to valves 26 a , 26 b , 28 a , and 28 b for controlling those valves, but the control connections between the controller 50 and the respective valves are not shown in FIG. 2 so as to avoid unnecessarily cluttering the Figure.
[0039] FIG. 3 shows an alternative arrangement of the system embodying aspects of the present invention. In the embodiment of FIG. 3 , each inlet port 12 , 14 , 16 is coupled to a three-way valve for selectively connecting the port either to pressure source # 1 22 , or pressure source # 2 80 . More specifically, inlet port 12 is coupled to valve 82 configured to selectively connect the inlet port 12 to pressure source # 1 22 via pressure lines 88 , 90 , and 100 or to pressure source # 2 80 via pressure lines 96 , 98 , and 100 . Inlet port 14 is coupled to valve 84 configured to selectively connect inlet port 14 to the pressure source # 1 22 via pressure lines 90 and 102 or to pressure source # 2 80 via pressure lines 96 and 102 . Inlet port 16 is coupled to pressure valve 86 configured to selectively couple port 16 to pressure source # 1 22 via pressure lines 90 , 92 and 104 or to pressure source # 2 80 via pressure lines 96 , 94 and 104 . Outlet port 18 is coupled to valve 122 for selectively connecting outlet port 18 to pressure source # 1 22 via pressure lines 106 and 46 .
[0040] Controller 50 controls pressure source # 1 22 via control line 52 and controls pressure source # 2 80 via control line 110 . Controller 50 also controls pressure valve 120 via control line 118 , pressure valve 82 via control line 116 , pressure valve 84 via control line 114 , and pressure valve 86 via control line 112 .
[0041] To generate fluid flow from inlet port 12 , control valve 120 is activated (e.g., by controller 50 ) to connect outlet port 18 to pressure source # 1 22 , and control valve 82 is activated to connect inlet port 12 to pressure source # 2 80 . The pressure generated by pressure source # 2 80 is preferably greater than the pressure generated by pressure source # 1 22 . Thus, a negative pressure differential is created between outlet port 18 and inlet port 12 . Inlet ports 14 and 16 are connected, by valves 84 and 86 , respectively, to pressure source # 1 22 for a period of time to equalize the pressure between the inlet port and the inlet of the microchannel, and then shut off valves 84 and 86 to maintain an established pressure, so there is no pressure differential between inlet ports 14 and 16 and the inlet of the microchannel and thus no fluid flow from inlet ports 14 and 16 to outlet port 18 . To stop fluid flow from inlet port 12 , control valve 82 is activated to connect inlet port 12 to pressure source # 1 22 to equalize the pressure between the outlet port 18 and the inlet port 12 and then shut off control valve 82 .
[0042] To generate fluid flow from inlet port 14 , control valve 84 is activated to connect inlet port 14 to pressure source # 2 80 to create a negative pressure differential between outlet port 18 and inlet port 14 . Valves 82 and 86 to inlet ports 12 and 16 are closed off, so there is no pressure differential between inlet ports 12 and 16 and inlet of the microchannel and thus no fluid flow from inlet ports 12 and 16 to outlet port 18 . To stop fluid flow from inlet port 14 , control valve 84 is activated to connect inlet port 14 to pressure source # 1 22 to equalize the pressure between the inlet of the microchannel and the inlet port 14 , and then valve 84 is shut off to maintain this pressure equilibrium.
[0043] To generate fluid flow from inlet port 16 , control valve 86 is activated to connect inlet port 16 to pressure source # 2 80 to create a negative pressure differential between outlet port 18 and inlet port 16 . Inlet ports 12 and 14 are connected, by valves 82 and 84 , respectively, to pressure source # 1 22 for a period of time to equalize the pressure between the inlet port and the inlet of the microchannel, and then shut off valves 84 and 86 to maintain an established pressure, so there is no pressure differential between inlet ports 12 and 14 and outlet port 18 and thus no fluid flow from inlet ports 12 and 14 to outlet port 18 . To stop fluid flow from inlet port 16 , control valve 86 is activated to connect inlet port 16 to pressure source # 1 22 to equalize the pressure between the outlet port 18 and the inlet port 16 , and then shut off control valve 86 .
[0044] As an alternative arrangement, three-way valves 82 , 84 , 86 could each be replaced by two two-way valves for selectively connecting each associated inlet port with pressure source # 1 22 or pressure source # 2 80 .
[0045] Suitable valves for use in the present invention include two-way and three-way solenoid valves by IQ Valves Co., Melbourne, Fla. and The Lee Company, Westbrook, Conn.
[0046] The systems shown in FIGS. 1 , 2 and 3 can be utilized in a process for performing PCR within discreet droplets of assay reagents flowing through a microchannel and separated from one another by droplets of non-reacting fluids, such as buffer solution, as is described in commonly assigned, co-pending U.S. application Ser. No. 11/505,358. The process will be described with reference to FIGS. 4 and 5 .
[0047] FIG. 4 is a flow chart illustrating the steps for performing PCR within discreet droplets flowing through a microchannel, and FIG. 5 shows time history curves representing the flow of various materials through the channel. The process will be described with reference to the system shown in FIG. 1 . It should be understood, however, that the process could also be performed with the systems of FIGS. 2 or 3 or a hybrid combination of the systems of FIGS. 1 , 2 , and 3 .
[0048] Referring to FIG. 4 , at step 130 negative pressure is applied to the outlet port 18 and all of the inlet ports 12 , 14 , 16 , etc, by connecting the ports, via the associated valves, to negative pressure source 22 , and by shutting off the valves to inlets 12 , 14 , and 16 . This is known as a stop condition as there is no pressure differential between the waste port and any inlet port, and thus no fluid flow into the microchannel 20 .
[0049] In step 132 , the valve coupled to the DNA/buffer inlet port (e.g., valve 24 associated with inlet port 12 ) is switched from negative pressure to atmospheric pressure to generate a sample flow condition (i.e., a negative pressure differential between outlet port 18 and inlet port 12 ) as shown by the curve 162 in FIG. 5 . Although not shown in FIG. 4 , a valve coupled to a polymerase inlet port may also be switched from negative pressure to atmospheric pressure to generate a polymerase flow as shown by curve 164 in FIG. 5 . The DNA/buffer mixture is combined into a common flow through the microchannel 20 .
[0050] In step 134 , a timer delay is implemented to fill the channels with the DNA/buffer (and optionally polymerase) mixture.
[0051] In step 136 , the valve coupled to a PRIMER 1 inlet port (e.g., valve 26 associated with inlet port 14 ) is switched from negative pressure to atmospheric pressure to generate a primer flow condition into the microchannel 20 to be mixed with the sample flow stream. A timer delay that is proportional to the desired timer injection volume is implemented in step 138 to control the volume of PRIMER 1 that flows into the mixture. In step 140 , the valve coupled to PRIMER 1 inlet port is switched to the original condition, i.e., negative pressure with the valve shutting off, to stop primer flow, thereby generating the first portion of flow curve 166 (through clock interval 4 ) in FIG. 5 .
[0052] A timer delay proportional to a desired spacer interleave is implemented in step 142 . This is a sample flow condition without primer flowing.
[0053] In step 144 , the valve coupled to the primer 2 inlet port (e.g., valve 28 associated with inlet port 16 ) is changed from negative pressure with the valve shutting off to atmospheric pressure to generate a primer flow condition into the microchannel 20 to be mixed with the sample flow stream. A timer delay that is proportional to the desired injection volume of primer 2 is implemented in step 146 . And, in step 148 , the valve coupled to the primer 2 inlet port is switched back to the original, negative pressure with the valve in the shut off condition to stop the flow of primer 2 . Steps 144 , 146 , and 148 generate the flow curve 168 shown in FIG. 5 .
[0054] In step 150 , a primer injection sequence is repeated for additional primers and additional, discrete injections of previously-injected primers until the complete assay conditions are generated, thus generating flow curve 170 . The resulting sample test stream flow curve is designated by curve 172 in FIG. 5 in which each “hump” in the curve represents a discrete volume of a primer mixed in the sample flow stream. A separate PCR (or other) assay can be performed in each discrete volume (or bolus) of sample/primer mixture.
[0055] In step 152 , PCR thermal cycling is performed on the flowing microfluidic stream thereby generating a PCR amplification reaction within each test bolus. In step 154 , a DNA thermal melt analysis is performed on the flowing microfluidic stream. And, in step 156 , a sequence of assay thermal melt data is generated for each test bolus for a multiplex assay performed within the microchannel 20 .
[0056] As shown in FIG. 6 , any valve coupled to an inlet port can be operated in a pulse width modulated manner to regulate the volume of fluid injected at the inlet port. For example, as described above, a valve coupled to an inlet port can be set to a flow condition for a predetermined period of time corresponding to a desired volume of fluid to be injected into the microchannel. A smaller volume of fluid can be injected by having the valve coupled to the inlet port set to the flow condition for a shorter period of time. It may be desirable, however, to produce reaction droplets of a specified physical size and, thus, it may be desirable to have fluid flow from the inlet port for the specified period of time (and not the shorter time corresponding to the smaller volume). To produce a lower volume of fluid flow from an inlet port while maintaining the flow from the port for a specified period of time, the valve coupled to the port may be modulated between negative pressure and atmospheric pressure (or other higher pressure) over the desired flow period, as shown in curves 174 and 176 in FIG. 6 . The resulting pressure at the inlet port is indicated by curve 180 in FIG. 6 . The resulting reagent flow, as shown in curve 178 in FIG. 6 , is a generally constant flow over the entire flow period at a flow rate that will result in a lower volume of fluid injected than if the inlet valve were kept open to atmospheric pressure for the entire flow period.
[0057] While various embodiments/variations of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments. Further, unless stated, none of the above embodiments are mutually exclusive. Thus, the present invention may include any combinations and/or integrations of the features of the various embodiments.
[0058] Additionally, while the processes described above and illustrated in the drawings are shown as a sequence of steps, this was done solely for the sake of illustration. Accordingly, it is contemplated that some steps may be added, some steps may be omitted, and the order of the steps may be re-arranged. | 4y
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BACKGROUND OF THE INVENTION
a. Field of the Invention
The present invention relates generally to automatic tank gauging (ATG) systems that use an acoustic or ultrasonic sensor system to measure level and temperature, as well as changes in level and temperature, in liquids stored in underground and aboveground tanks; it applies particularly to novel reference subsystems and methods for monitoring (1) the level of that liquid, (2) small changes in the level and temperature of that liquid, (3) the level of a second liquid that is immiscible with the first liquid and that is usually located near the bottom of the tank, and (4) leakage from the tank.
b. Brief Discussion of the Prior Art
Automatic systems for making level and volumetric measurements in storage tanks are well known in the petroleum and chemical industries and are generally included, under the category of automatic tank gauging systems, in the United States Environmental Protection Agency (EPA) regulation for underground storage tanks containing petroleum liquids and other chemical liquids considered hazardous to the environment. Petroleum and chemical liquids are referred to as "product" in order to differentiate them from water, another liquid that may be present in the tank at the same time (water, which accumulates at the bottom of the tank, is an undesired entity).
The EPA presently gives three options for tank testing. The first option is an ATG, which must (1) do inventory control (i.e., make water-level and product-level measurements accurate to 1/8 in.) and (2) perform a leak detection test (i.e., detect leaks as small as 0.2 gal/h with a probability of detection (P D ) of 95% and a probability of false alarm (P FA ) of 5%). The ATG reconciles product inventory on a monthly basis, using the product-level measurements combined with dispensing and delivery data obtained by other means. In addition, the ATG must be used monthly to perform a leak detection test. The second option is a volumetric or "tank tightness" test, which, like an ATG, must make inventory control measurements of water level and product level accurate to 1/8 in. and must perform a leak detection test. It must, however, be able to detect leaks twice as small as those detectable by an ATG, specifically, 0.1 gal/h with a P D of 95% and a P FA of 5%. If one chooses this more stringent option, the minimum time interval between tests required by the regulation is once a year. The EPA specifies a third option under Other Methods in the regulatory document; to satisfy this option one must test the tank monthly with any method that can detect a release of 0.2 gal/h using a P D of 95% and a P FA of 5%.
An ATG can be used to satisfy any of these three options as long as it meets the criteria defined for that option by the EPA. Moreover, the present invention, when used for leak detection, may be used either as an ATG or a tank tightness test.
A wide variety of ATGs have been developed and are currently on the market. A few of these use acoustic systems to measure product level and water level, both for inventory control and for conducting a leak detection test. The acoustic frequency selected for the system is such that an acoustic pulse will propagate in a liquid but not in a gas and will be reflected from any strong density discontinuity, such as the interface between a liquid and a gas, the interface between two immiscible liquids (e.g., gasoline and water), or a solid object (e.g., brass, steel, or nylon). When the interface is between a gas and a liquid, almost all of the acoustic energy is reflected; with a liquid-liquid interface, or a reflecting target (known as a "fiducial") that is narrower than the acoustic beam, some of the acoustic energy is reflected and some continues to propagate toward the liquid surface (in most systems, the acoustic transducer is placed on or near the bottom of the tank and pointed upward). If the average speed of sound over the propagation path is known, the height of the liquid above the transducer can be estimated from the time it takes for an acoustic pulse to travel back and forth once between the transducer and the product surface. The speed of an acoustic pulse through liquids such as those found in storage tanks depends on the temperature and chemical composition of the liquid. For a given liquid, the speed is directly proportional to the temperature over the range of ambient product temperatures, which is similar to the range of ground and air temperatures. Thus, the round-trip travel time between the transducer and the surface will depend on the vertical temperature profile of the liquid in the tank at the time of the measurement. Experimental measurements made in storage tanks show that a wide range of temperature profiles can exist (FIG. 1). Most ATGs use a calibration target located at a known distance from the transducer to estimate the propagation speed (i.e., sound speed) within a liquid medium; this is a widely accepted and widely published method, particularly in underwater sound measurements. The ATG makes an estimate of the average sound speed between the transducer and the surface from the time it takes for an acoustic pulse to travel round trip between the transducer and a solid reference target, such as fiducial 210, that is located a fixed and known distance above the transducer and below the liquid surface (FIG. 2); the time is then converted to distance. What is not included in this average sound speed is that portion of the liquid between the fiducial and the surface. Therefore, if the temperature in this layer differs from the average temperature in the layer between the transducer and the fiducial, errors in estimating the speed of sound through the liquid may occur, and this will affect the accuracy of the liquid-level estimate made by the system. If the acoustic transducer is located below the water/product interface, as shown in FIG. 3, the estimate of the sound speed obtained from the fiducial 210 will not reflect the propagation speed through product alone, but will include the effects of the water. (Accuracy also depends, of course, on the performance characteristics of the measurement system itself.)
An acoustic ATG is also used to measure the level of the water that accumulates at the bottom of a storage tank. It is generally understood that the maximum level of water that an ATG must be capable of measuring is 4 in. A higher water level is likely to interfere with or contaminate the liquid that is being dispensed from the tank. If water is immiscible with the liquid in the tank, which is the case with petroleum, the product most commonly stored in underground tanks, an acoustic ATG can be used to measure it. In principle, this measurement can be made in two ways. The first way is to position the transducer below the water/product interface and measure the round-trip travel time of the acoustic signal reflected from the interface (FIG. 4). The travel time is converted to distance by selecting an average value of sound speed through water from published tables. This method is more than sufficient for providing a level measurement accurate to within 1/8 in. For a number of reasons, this measurement is difficult to make if the water/product interface is too close to the transducer, and, as a consequence, this measurement approach has not been used commercially to measure the water level near the bottom of the tank. The second way is to position the transducer above the water/product interface and measure the difference in the travel time for an acoustic signal to propagate (1) from the transducer to the product surface to the water/product interface, then back to the surface and back again to the transducer (FIG. 5(a)); and (2) from the transducer to the product surface to the bottom of the tank, then back to the surface and back again to the transducer (FIG. 5(b)). The water level can be estimated from this first propagation path alone if the height of the transducer from the bottom of the tank is known and if the average sound speed over the entire propagation path can be estimated. Because temperature gradients are largest near the bottom and top of the liquid in the tank, errors in estimating sound speed occur in the liquid layer above the fiducial closest to the surface and the layer below the transducer. These errors can sometimes be large.
Leak detection is difficult because the thermal expansion and contraction of the volume of the product in the tank must be accurately estimated and removed from the volume changes derived from the level changes measured with an ATG. Accurate temperature compensation is difficult because the rate of change of temperature and the volume of the product in the tank, which is usually proportional to the circular cross-section of the tank, are not uniform with depth. Typically, when new product is delivered to an underground storage tank, there is a significant temperature difference between the new and extant products. This temperature difference arises because the product stored in an underground tank is likely to be in equilibrium (or nearly so) with the surrounding soil and backfill material, while the delivered product may have been transported in a tanker truck exposed to ambient air and sunlight conditions for a long time. Further, the tanker may have obtained the product from an above-ground tank, whose contents might have been much warmer (or colder) than the temperature of the ground where the receiving tank is located. When products of different temperatures are mixed, a thermal separation occurs with (usually, but not always) the warmer product rising to the top as the colder product settles to the bottom, with an infinite variety of different temperature profiles or "thermal gradients" between the top and bottom of the tank 10, such as illustrated in FIG. 1. Depending on the volume capacity of the storage tank, the thermal properties of the soil and backfill and the differences in temperature between the product in the tank and the soil and backfill, it can take many days for the combined products to reach near-equilibrium conditions again. In this attempt to reach a near-equilibrium condition, the rate of change of temperature may differ significantly over the depth of the tank. Because acoustic measurement systems are affected by the temperature over the entire propagation path between the transducer and the surface, they can be used to vertically integrate the changes in temperature over the depth of the product in the tank. When these measurements are made over a period of time, an acoustic system is particularly good for measuring the average change in temperature of the product within the tank.
An ATG can be used to conduct a volumetric leak detection test if both the average change in temperature of the product in the tank, which is weighted in the vertical by the volume of the product as a function of height above the bottom of the tank (i.e., by the cross-sectional area of the tank), and the change in level of the product can be measured over a period of time. The average thermally induced volume change is estimated by taking the mathematical product of the average volumetrically weighted temperature change, the coefficient of thermal expansion of the liquid, and the total volume of the liquid in the tank. When measurements are made in a partially filled tank, the average volume change is estimated from the average liquid-level change by means of a height-to-volume conversion factor determined from the tank geometry. (In an overfilled tank, volume change cannot be estimated from a height-to-volume conversion based on tank geometry, but must be measured experimentally.) The average temperature-compensated volume rate is calculated by subtracting the average thermally induced volume change from the average volume change. On the average, if the data are properly sampled to avoid aliasing the surface and internal waves that are frequently present in the tank, and if the liquid level changes due to the structural deformation of the tank and to the evaporation and condensation within the tank are also compensated for, this net volume change should, in a nonleaking tank, be equal to zero. The temperature-compensated volume rate is then compared to a predetermined threshold volume rate to determine whether the tank should be declared leaking. The performance of the leak detection system in terms of P D and P FA can be estimated if one generates a histogram of many individual leak detection tests on a nonleaking tank over a wide range of environmental conditions that affect the performance of the method, such as ground and product temperature conditions, and if one knows the relationship between the volume changes due to a leak and the volume changes due to any other physical mechanisms active in the tank environment. Acoustic ATG systems typically make an estimate of the average vertical temperature and average level change from a sound-speed estimate made with a fiducial located below the surface of the product. This fiducial is required so that one can compensate for the effects of temperature and level on the round-trip travel time of the acoustic pulse. When the average temperature change is estimated in this way, the temperature changes are not weighted by volume, and large temperature changes near the top and bottom of the tank, where the height of the product is great in comparison to its volume, can result in large differences between the depth-averaged temperature and the depth-averaged volumetrically weighted temperature. Therefore, the closer the fiducial is to the surface, the better the estimate of the average temperature and level changes will be. If the fiducial is located too far below the surface, it is likely that there will be large errors in the measurement of the liquid-level changes. Ideally, the fiducial should be collocated with the surface, but then it would be impossible to measure the acoustic returns from both the surface and the fiducial and to distinguish between them. Generally, a fiducial cannot be placed any closer to the surface than 1 to 2 in. This constraint is imposed by the width of the acoustic pulse, its reverberation, and the time required to process the data.
In U.S. Pat. Nos. 4,748,846 and 4,805,453, Haynes describes an ultrasonic ATG system and several methods for measuring the level of the product and water in a tank, a method for measuring the average sound speed through the product in a tank and the average temperature of this product, and a method for detecting theft or leaks in a tank. Haynes uses a number of fixed references or fiducials, rigidly and permanently attached to a staff that is inserted vertically into the tank, as shown in FIG. 2. The fiducials are separated by some predetermined distance, and preferably are equidistant from one another. The number of fiducials is not specified, nor is the spacing between them, but in a tank that is 8 ft in diameter there are typically 8 fiducials spaced approximately 12 in. apart. More fiducials can be used, but the spacing should not be so close that it becomes an intractable measurement problem to determine which acoustic return is associated with which fiducial or to determine which return is from the surface. Multiple returns from lower fiducials have round-trip travel times similar to the first return from higher fiducials, and the multiple returns from the fiducials and the surface have the same arrival times as the returns from the fiducials themselves. In addition, there is the possibility of missing a weak return from any one or more fiducials; this results in a counting (i.e., location) error. Furthermore, the minimum spacing, as determined from the duration of the acoustic pulse, reverberation, and processing time, is limited to 1 to 2 in. As a consequence, the fiducial closest to the product surface may be anywhere between 2 and 12 in. from it.
Haynes uses a single fiducial, the one that is closest to the surface, to measure product level and water level, to measure average temperature, and to make an estimate of the temperature-compensated volume for the purpose of leak detection. The transducer is located near the bottom of the tank, but above the maximum height of any water that might accumulate there. The system uses a threshold detection approach to measure the round-trip travel time of the acoustic signals reflected from all of the fiducials, the surface, the water/product interface, and the bottom of the tank. Haynes uses either of the configurations shown in FIG. 5 to estimate the water level; he states that when the water/product interface is close to the transducer, the configuration shown in FIG. 4 does not work.
There are a number of problems with the ATG system described by Haynes that affect the accuracy of the product-level and water-level measurements, as well as the leak detection test itself. All of the measurements require that both the surface and the fiducial immediately below the surface be identified. Multiple echoes can cause mistakes in finding the surface or the uppermost submerged fiducial. A secondary echo that has a round-trip travel time less than but very close to that of the first acoustic pulse may be detected instead of the first return of the pulse, resulting in an erroneous measurement of the distance between the transducer and the fiducial or surface. Since errors of 0.01 to 0.001 in. are significant, large errors can be made in estimating the sound speed, which is in turn used to make estimates of the product level, temperature, and water level. In general, a fiducial located within 12 in. of the surface will usually result in an estimate of the surface height accurate to within 1/8 in. or better. However, even a fiducial located an average of 6 in. away from the surface will produce unacceptably large systematic errors in the leak detection approach. Significant temperature gradients and, therefore, soundspeed gradients occur in the layer immediately below the surface, and thus placement of a fiducial more than 2 to 3 in. from the surface can result in large errors in the measurement of the level changes. In addition, an error in leak detection can occur because the temperature changes are not volumetrically weighted by the cross-sectional area of the tank. The approach to making water-level measurements that is shown in FIG. 5(a), where the pulse is reflected back to the transducer via the route surface-interface-surface, is susceptible to errors in that it is difficult to distinguish the interface return from the primary and secondary fiducial and surface returns. Errors in measuring the distance between the transducer and the interface are also likely to occur, because the speed of sound in the area between the transducer and the interface is not known, nor is the speed of sound between the uppermost submerged fiducial and the surface known.
In a number of other types of liquid-level measurement devices, floats have been used to track surface fluctuations. For example, U.S. Pat. No. 4,158,964, issued to McCrea et al., disclosed an ultrasonic level-measurement system that is very different from Haynes's acoustic system. In the McCrea invention, an aultrasonic pulse is transmitted vertically through a waveguide made of a homogeneous aluminum alloy having a low thermoelastic coefficient. Permanent magnets are located at the top and bottom of the waveguide and on a donut-shaped float that is concentrically positioned about the waveguide and that is free to move up and down with liquid-level changes. These magnets produce a low-level, bipolar voltage pulse that is generated across the waveguide as the acoustic pulse transmitted along the waveguide passes the magnet. The permanent magnets at the top and bottom of the tube are used as a calibration reference to interpret the speed of the pulse in the waveguide. The magnets in the float are used to determine the position of the float along the waveguide.
SUMMARY OF THE PRESENT INVENTION
It is an object of the present invention to provide a method, and several devices that implement this method, for reliably detecting small leaks in tanks used to store liquids.
Another object of the present invention is to provide a method, and several devices that implement this method, for measuring the level of product in a storage tank containing a liquid.
Another object of the present invention is to reduce the number of fiducials in an ATG device in such a way as to (1) minimize the number of secondary acoustic echoes that make it difficult or impossible to correctly identify the return from the fiducials, the product surface, and the water/product interface, and (2) still make accurate measurements of product temperature, product level, and water level, as well as precise measurements of product-level changes and temperature changes, and thus to conduct a leak detection test that meets or exceeds the present EPA performance standards.
Another object of the present invention is to provide a method whereby a novel quasistatic, floating reference device that has fiducials attached to it, that is used for calibration purposes, and that is always located as close to the liquid surface as desired rigidly attaches itself to a vertical support inserted into the tank and remains fixed for the precise measurement of product-level and temperature changes required for leak detection, but changes position when the level of liquid in the tank changes by a predetermined amount.
Another object of the present invention is to provide a method, and several devices that implement this method, for measuring the average speed of sound in a layer of liquid immediately below the surface.
Another object of the present invention is to provide several methods of accounting for variations in sound speed that occur as an acoustic signal passes through a fluid of varying density, as would be required for accurate product-level and leak-detection measurements within a storage tank containing a liquid.
Another object of the present invention is to provide a method, and several devices that implement this method, for measuring the average change in the temperature of a liquid product within a storage tank and compensating for the thermal expansion and contraction of that product during a leak detection test.
Another object of the present invention is to provide a method, and several devices that implement this method, for measuring the average change, weighted volumetrically by the cross-sectional area of the tank, in the temperature of a liquid in that tank.
Another object of this invention is to provide a method, and several devices to implement this method, for measuring the level of the water accumulated at the bottom of a storage tank that contains a liquid immiscible with water by means of an acoustic transducer, mounted either above or below the water/product interface, that emits a signal that is reflected from the water/product interface.
A final object of this invention is to provide a method, and several devices that implement this method, for measuring the level of the water at the bottom of the tank without using the acoustic backscatter from the water/product interface.
Briefly, the preferred embodiment of the present invention comprises an automatic tank gauging system having a quasi-static reference subsystem (a floating fiducial device) for measuring product level and leaks in storage tanks containing liquids. The tank gauging system includes a probe assembly, a transducer controller mounted at the top of the probe assembly, and an external system controller in electrical communication with the transducer controller. The probe assembly is comprised of (1) an insertion tube, (2) an acoustic transducer mounted toward the bottom of the tube and aimed toward the surface of the product, (3) an acoustic transducer aimed toward the bottom of the tank and mounted below the upward-aimed transducer and above the maximum level that water may accumulate at the bottom of the tank, (4) at least two fiducials, or fixed references, positioned below the liquid in a half-filled tank and at defined intervals with respect to the acoustic transducer, (5) a temperature sensing device positioned near the bottom of the tank, and (6) a quasi-static reference subsystem having at least one fiducial that provides a fixed reference point when the product level in the tank is in equilibrium (i.e., not fluctuating) and that adjusts its position with respect to the transducer when the level rises or falls by a predetermined increment. The preferred embodiment of the quasi-static reference device is a float having a predetermined specific gravity, a wheel having a multifaceted magnetized circumference wherein each facet of the wheel has a length approximately corresponding to the predetermined incremental change in product level, and which wheel keeps the quasi-static reference device affixed to the inner wall of the tube when the product is in a state of equilibrium, and a support member for the wheel and for the addition of a guide magnet (or "slider" magnet), if necessary, that keeps the float vertically aligned. Also attached to the float are one or more fiducials for use as reference for the acoustic transducer. When in operation, the upper transducer emits a series of acoustic pulses upward through the probe assembly and through the product; these pulses are reflected by the fixed and quasi-static reference fiducials and by the surface of the product. The lower transducer emits a series of acoustic pulses downward through the probe assembly and through the product and any water that has accumulated at the bottom of the tank; these pulses are reflected by the water/product interface and the bottom of the probe assembly.
The transducer controller generally collects data at 50 to 100 Hz, averages the data to 1 Hz or less, computes several data quality indices, and transfers the data and the indices to the external system controller for further reduction, analysis, and storage. The external controller generally averages the data to between 0.0167 and 0.0833 Hz (1 and 5 min/sample, respectively) for measurement of the average liquid level, the average water level, the average sound speed between all fixed and quasi-fixed fiducials and the transducer, the change in level of the liquid surface over time, and the change in temperature of the product over time averaged over the entire vertical extent of the tank after the temperature has been weighted by the cross-sectional area of the tank.
Although the present invention is primarily designed for use in the testing of underground storage tanks, it is not limited to that usage and could be easily be applied to testing above-ground storage tanks as well.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1a through 1g are diagrammatic representations of different temperature profiles that can be encountered during measurements of the height of the product surface and the water/product interface, or during a leak detection test;
FIG. 2 is a cross-sectional view of a tank and acoustic measurement system with an upward-aimed transducer located above the highest level that the water may accumulate at the bottom of the tank before it must be removed;
FIG. 3 is a cross-sectional view of a tank and acoustic measurement system with an upward-aimed transducer located below the nominal level at which water may accumulate at the bottom of the tank;
FIG. 4 illustrates one scheme by which an acoustic system can measure the level of the water at the bottom of a tank; an upward-aimed transducer, located below the nominal level at which water may accumulate, receives the direct reflection of an acoustic pulse from the water-product interface;
FIGS. 5(a) and 5(b) illustrate other schemes by which in acoustic system can measure the level of the water at the bottom of the tank using an upward-aimed transducer that is located above the nominal level at which water may accumulate;
FIG. 6 illustrates the preferred embodiment of the automatic tank gauging system of the present invention;
FIG. 7 is a cross-sectional view of a probe assembly, with the middle section cut away, and a quasi-static reference in accordance with the preferred embodiment of the present invention;
FIG. 8 is a cross-sectional view of a first alternative embodiment of the "pinwheel" subsystem on the quasi-static reference device shown in FIG. 7;
FIG. 9 is a cross-sectional view of a second alternative embodiment of the pinwheel subsystem on the quasi-static reference device shown in FIG. 7;
FIG. 10 illustrates a first alternative embodiment of the quasi-static reference device shown in FIG. 7, comprised of a guide magnet located on the float;
FIG. 11 illustrates a second alternative embodiment of the quasi-static reference device shown in FIG. 7, comprised of a guide magnet located above the surface of the liquid and attached by means of a horizontal member to the support that connects the pinwheel to the float;
FIG. 12 shows front and side views of the preferred embodiment of the guide magnet on the quasi-static reference device shown in FIG. 7; this embodiment is a cylindrical magnet that rolls up and down on the wall of the vertical mount;
FIG. 13 shows front, side and top views of a first alternative embodiment of the guide magnet on the quasi-static reference device shown in FIG. 7; this embodiment is a thin magnet with a very low coefficient of friction that slides up and down on the wall of the vertical mount;
FIG. 14 shows front and side views of a second alternative embodiment of the guide magnet on the quasi-static reference device shown in FIG. 7; this embodiment is a magnetized ferromagnetic ball bearing that rolls up and down on the wall of the vertical mount;
FIG. 15 illustrates a third alternative embodiment of the quasi-static reference device shown in FIG. 7, comprised of a magnetic wheel located above the surface of the liquid and on the support that connects the pinwheel to the float;
FIG. 16 illustrates a first alternative embodiment of the probe assembly shown in FIG. 7; the two circular fiducials affixed to the vertical mount in FIG. 7 are replaced by two fiducials comprised of a long, thin bar having one of four different cross-sectional shapes, as shown;
FIG. 17 illustrates a second alternative embodiment of the probe assembly shown in FIG. 7; the addition of a bar-type fiducial such as that in FIG. 16 is located below the transducer and above the maximum level of water that may accumulate at the bottom of the tank;
FIG. 18 illustrates a third alternative embodiment of the probe assembly shown in FIG. 7; an upward-aimed transducer located below the nomial level at which water may accumulate at the bottom of the tank replaces the downward-aimed transducer of FIG. 7;
FIG. 19 illustrates a fourth alternative embodiment of the probe assembly; an upward-aimed transducer located below the nominal level at which water may accumulate at the bottom of the tank replaces the downward-aimed transducer of FIG. 7, and two bar-type fiducials such as those in FIG. 16 replace the two circular fiducials affixed to the vertical mount;
FIG. 20 illustrates a fifth alternative embodiment of the probe assembly; an upward-aimed transducer located below the nominal level at which water may accumulate at the bottom of the tank replaces the downward-aimed transducer of FIG. 7, and a bar-type fiducial such as that in FIG. 16 is placed below the transducer and above the maximum level of water that may accumulate at the bottom of the tank;
FIG. 21 illustrates a first alternative embodiment of the fiducials located on the quasi-static reference device shown in FIG. 7;
FIG. 22 illustrates a second alternative embodiment of the fiducials located on the quasi-static reference device shown in FIG. 7;
FIG. 23 illustrates (a) the computed sound speed profile in a gasoline tank filled to 78.7 inches corresponding to (b) the measured temperature profile;
FIG. 24 illustrates a fourth alternative embodiment of the quasi-static reference device shown in FIG. 7 that replaces the magnetic pinwheel device shown in FIG. 7 with a magnet- fulcrum subsystem that moves the reference device up and down the wall of the vertical mount;
FIG. 25 illustrates a fifth alternative embodiment of the quasi-static reference device shown in FIG. 7 that replaces the magnetic pinwheel of FIG. 7 with a magnet-fulcrum subsystem that moves the reference device up and down the wall of the vertical mount;
FIG. 26 illustrates a sixth alternative embodiment of the quasi-static reference device shown in FIG. 7 that replaces the magnetic pinwheel of FIG. 7 with a magnet-fulcrum subsystem that moves the reference device up and down the wall of the vertical mount;
FIGS. 27a through 27g illustrate the preferred embodiment and six alternative embodiments of the magnet and the upper and lower fulcrums of the quasi-static reference devices shown in FIGS. 24 through 26;
FIG. 28 illustrates an alternative embodiment of the magnet and the upper and lower fulcrums of the quasi-static reference devices shown in FIGS. 24 through 26;
FIG. 29 illustrates an alternative embodiment of the magnet and the upper and lower fulcrums of the quasi-static reference devices shown in FIGS. 24 through 26;
FIG. 30 illustrates an alternative embodiment of the magnet and the upper and lower fulcrums of the quasi-static reference devices shown in FIGS. 24 through 26;
FIG. 31 illustrates a first alternative embodiment of the vertical mount of FIG. 7, comprised of a flat plate or a large-radius cylindrical tube that permits the quasi-static reference device to move up and down with the product level in the tank in discrete steps; FIG. 32 illustrates a second alternative embodiment of the vertical mount of FIG. 7, comprised of a guide channel that permits the quasi-static reference device to move up and down with the product level in the tank in discrete steps;
FIG. 33 illustrates a third alternative embodiment of the vertical mount of FIG. 7 comprised of a guide channel with holders that permits the quasi-static reference device to move up and down with the product level in the tank;
FIG. 34 illustrates a seventh alternative embodiment of the quasi-static reference device shown in FIG. 7 that replaces the magnetic pinwheel of FIG. 7 with a magnet-fulcrum subsystem attached to the float by an axle: and
FIG. 35 illustrates an eighth alternative embodiment of the quasi-static reference device shown in FIG. 7 that replaces tha magnetic pinwheel of FIG. 7 with a magnet-fulcrum subsystem attached to the float by an axle and in which a guide magnet has been added to the float :
DESCRIPTION OF THE PREFERRED EMBODIMENT
An automatic tank gauging system and a volumetric leak detection system (tank tightness test) are illustrated in FIG. 6 as they would be used in an underground 8 storage tank 10 in accordance with the preferred embodiment of the present invention. The ATG has three main components: the probe assembly, shown as 12, a transducer controller 14, and a system controller 16. The transducer controller 14, which is mounted toward the top of the assembly 12 within an explosion-proof housing, controls the acoustic transducers 22, 23 and the temperature sensor 19. The system controller 16 is mounted to an above-ground support and is in electrical communication with the transducer controller 14 through a cable 17. The cable 17 carries power and command data from the system controller 16 to the transducer controller 14, and acoustic and temperature data from the transducer controller 14 back to the system controller 16. The cable is shown as fixed underground, but need not be. A cable is not necessary. The system controller and transducer controller can communicate telemetrically, with the transducer controller having a self-contained power supply.
The transducer controller 14 contains the pulse waveform shaping, transmitting and receiving, and digital preprocessing electronics for the ATG system. The system controller 16 contains the remainder of the hardware and software necessary to control the desired operationsl modes from the transducer controller 14, acquire the acoustic and temperature date, process the data in terms of product level, water level and leak rate, and display the results. The system controller 16 can also be equipped to control other sensor systems, such as those that provide overfill protection and alert, pipeline leak detection, detection of leaks in the annular space of a double-wall tank, detection of petroleum floating on the groundwater outside the tank, and detection of vapors in the soil and backfill outside the tank.
The probe assembly 12 is further comprised of a 2.0-in.-diameter tube 18 with ferromagnetic properties, preferably made of stainless steel, that is inserted into a riser 20 typically having a 2-to4-in. diameter, an acoustic transducer 22 mounted toward the bottom of the tank and facing upward, another acoustic transducer 23 mounted toward the bottom of the tank, two fixed fiducial references 24 and 26 positioned at defined intervals with respect to the transducer 22, a temperature sensor 19 mounted mid-way between the transducer 22 and the lower fiducial 24, and a quasi-static fiducial reference device 28, which provides a fixed reference point when attached to the wall of the tube and which adjusts its position with respect to the transducer 22 when the fluid level in the tank rises or falls by a predetermined increment. The quasi-static reference device 28 is further described below the particular reference to FIG. 7. The term quasi static indicates that the device 28 operates both as a float, which changes its position within the tube 18 when the height of the product 30 changes by a predetermined amount , and as a fixed reference point with respect to the surface 32 of the product.
FIG. 7 further illustrates the probe assembly 12, shown with the midddle section cut away so as to better illustrate the relationship between the transducer 22, the fixed references 24 and 26, and the quasi-static reference device 28. The tube 18 is substantiallly the same as the one illustrated in FIG. 6, with the exception of the inlet/outlet valves 34 and 35, which allows fluid from the tank to flow into the tube 18. One advantage of the present invention is that the entire reference system (the transducer 22 and references 24, 26, 46, and 48) is contained within the tube 18, rather than extending from the outside of the tube as is common in the prior art. The fact that this reference system is self-contained makes the ATG easier to handle when it is being inserted in or removed from the tank 10; it makes the device less likely to be damaged; and it provides a more controllable environment.
The transducer 22 is in electrical communication with the transducer controller 154 (FIG. 6) by means of a conductor (not shown) traversing the length of the tube 18. As noted above, communication may also be telemetric. The transducer 22 receives command data from the transducer controller 14 and transmits a series of accurately timed acoustic pulses up the probe, through the produce, and to the various fiducials. Fiducials 24 and 26 (FIG. 7) comprise the bottom circumference of two concentric thin-walled nylon tubes separated in the vertical by a known distance; the nylon sleeve 31 with fiducials 24 and 26 fits into the ferromagnetic tube that holds the probe assembly. Fiducial 24, F 0 , is preferably positioned at a height, h 1 , about 18 in. above the bottom of an 8-ft-diameter tank, while fiducial 26, F 2 , is preferably positioned at a height, h 2 , about 30 in. above the bottom of the tank. The positioning of these fiducials, which varies depending on the diameter of the tank, will be further explained below. In operation, acoustic pulses transmitted by the transducer 22 are reflected from the fiducial references 24 and 26 and the surface 32 of the product in the tank.
The quasi-static reference device shown in FIG. 7 is comprised of a cylindrical float 36, a magnetized pinwheel 38, and a support 42 that links the wheel to the other components of the device. The purpose of the cylindrical float is to provide bouyancy for the reference device. The purpose of the magnetized pinwheel is to provide a means of incrementally changing the vertical position of the reference device as the product level rises or drops by a predetermined distance. FIG. 7 also shows the nominal level of the produce 32 when the device is attached to the wall, and the level to which the produce must rise 162 or fall 164 to cause the device to pull away from the wall and reattach itself as a higher or lower level. In general, this rise or drop is between 0.25 and 0.5 in.
The cylindrical float is made of a very lightweight foam whose specific gravity is small compared to that of the produce in the tank. Gasoline, diesel, and kerosene produces have a specific gravity between 1.7 and 0.9, whereas water has a specific gravity of 1.0. The specific gravity of the foam is approximately 0.1, but the specific gravity can be more or less depending on the weight of the other components of the reference device 28. The upper fiducial 46 is designed to remain in a fixes position relative to the transducer over the duration of a leak detection test. If the reference device 28 moves during a test, the accompanying 0.25 to 0.5 in. drop or rise in product level will be large enough to be easily distinguished from naturally occuring level changes; if this happens, the test will nullified and will have to be restarted. The specific gravity and volume of the cylindrical float is especially designed in relation to the other components of the reference device 28 so that the fiducial 46 can maintain one of two positions with respect to the surface 32 of the product. It is designed to keep the upper fiducial 46 of the reference device 28 as close to the surface as possible and still permit measurements of changes in produce height that are independent from those of upper fiducial 46. It is designed to rise or fall in steps of 0.25 to 0.5 in. after the level of the product has changed by a corresponding amount. Although such changes are generally considered small in an absolute sense, they are large in comparison to the changes that can be expected to occur during a leak detection test, when non-leak-related changes are present in addition to leak-related ones. In the preferred embodiment, the minimum distance between the product surface 32 and the upper fiducial 46 is approximately 1.75 in., which is controlled by the width of the acoustic pulse and the method of acquiring the data. During a test, the reference device 28 and the upper fiducial 46 (which is physically located about 2 in. or less below the surface) are fixed with respect to the transducer. The fiducial 46 and 48 on the bottom of the reference device are used to measure changes in sound speed and temperature in the layer of product between the transducer and the liquid surface. The product level can rise or fall only a certain amount (i.e., a defined minimum and maximum distance in terms of height) before the reference device detaches itself from the wall, moves up or down one increment, and reattches itself ast a new level. The incremental distance that the reference device 28 is designed to move is such that upper fiducial 46 will always be close enough to the surface so that any error in estimating the average changes in sound speed will be small enough not to impact the leak detection pereformance of the ATG.
The wheel 38 rotates about an axle 44 extending through the wheel 38 and held in place by the support 42. The wheel 38 has a diameter somewhat smaller than the internal diameter of the tube 18 and is about 1/8 to 1/4 in. thick at its circumference. The circumference is not smooth but is comprised of a number of segments, or facets, of equal length. These facets, made of permanent magnetic material are laid end to end around the periphery of the wheel. As shown in FIG. 7, if the internal diameter of the tube is 11/2 in, and the circumferential diameter of the wheel is 11/4 in., the wheel could be configured so as to have 12 facets, the strength of the magnetized segments of material, the strength of the guide magnet 40, is one is used, (see alternative embodiments of the reference device below) and the amount of change in product level, the reference device 28 can be designed to move in certain incremental amounts in accordance with the incremental changes in the level of the product.
When the product level drops 164 or rises 162, the gravitational or buoyant forces exerted on the reference device 28 exhibit a corresponding change, thereby creating a moment centered about the point of contact the tube 18 and the attched facet 74 in the direction of the product-level change. Hence, a sufficient decrease in product level would create a corespondingly sufficient moment force at this point of attachment; the moment force would overcome the strength of the magnetized segment, causing the wheel 38 to rotate and travel down the side of the tube 18. The same physical principle applies in the inverse to increase in the product level.
The optimum minimum and maximum distances that the reference will remain fixed to the wall of the vertical mount before dropping or rising can be determined from the analysis of a free-body force and moment diagram. Overall, these distances depend on the bouyancy exerted by the liquid on the reference device (upward force), the weight of the reference device (downward force), and the frictional forces produced by the magnetized facets. The reference device will fall (or rise) when the net vertical forces are sufficient to create a moment about the center axle of the pinwheel 474 that overcomes the facet's magnetic attraction to the wall and causes the wheel to rotate about the lower (or upper) edge 70, 72 of the magnetic facet attached to the tube. The overall center of gravity of the reference device is designed to be as low as possible to ensure that the device will rise and fall along a line that is perpendicular to the surface; this guarantees that the acoustic return from the fiducials 46 and 48 will be strong.
Two alternative embodiments of the pinwheel are shown in FIGS. 8 and 9. In both embodiments, discrete magnets are used at each fulcrum point, but the number of fulcrum points is the same as the number of facets in the preferred embodiment. The three embodiments in FIGS. 7,8, and 9 are thus functionally similar. An analysis of the static forces and moments on the alternative embodiments of the pinwheel shows the important tradeoffs in the design of the reference device 28. The number of magnetic facets can be calculated from a free-body analysis and depends on the strength of the magnetic material, the coefficient of friction between the magnet and (1) the wall, and (2) the angle between axle and the lower edge of the magnet facet attached to the wall. This analysis assumes that the pin and the axle are frictionless. The results of the analysis show that the device will function properly in both the upward and downward direction if the following relationships are satisfied: ##EQU1## where
θ=the arc angle between the upper 73 and lower 71 magnetic contact points
F mi =the magnetic force at the lower contact point 71
F m2 =the magnetic force at the upper contact point 73
α=the coefficient of friction between the magnet and the wall at a lower contact point 71
β=the coefficient of friction between the magnet and the wall at a upper contact point 73 If magnets of the same strength, size and material are used all around the pinwheel, then α=β and F m1 =F m2 and the reference device will function in both directions if the following relationship is satisfied: ##EQU2## A pinwheel with N magnets satisfies the condition imposed by the friction conditions in Eq. (3). The number N of equally spaced magnets around the circumference is θ=2π/N. For a large number of magnets ##EQU3## If N=12, for example (α=β) must be less than or equal to 0.25 for F m1 =F m2 .
The analysis shows that a minimum number of facets is required for the reference device to move in incremental steps rather than slide continuously in tandem with the surface changes. If the number of facets is too small, the frictional force at the fulcrum point 70 in FIG. 7 during a rotation of the pinsheel may be too small to prevent the system from sliding without completing a one-facet rotation. If the number fo facets is too large, the dynamic force produced when the reference device is dropping (and not accounted for in the static analysis presented below) may result in a rotation of the pinwheel greater than one facet. This would not interfere with the primary function of the reference device if, when the device came to its new position and reattached itself to the wall of the tube, it did so squarely on the next facet and not in an intermediate position centered on the edge between two facets. If the latter occurred, the reference device would not remain in a fixed position on the wall but would rotate into a position of equilibrium with the changing product level. With common magnetic materials and a magnetized stainless steel tube that is 1.5 in. in diameter, a pinwheel with 10 to 14 facets functions is preferred.
As shown in FIG. 7, the reference device will drop or rise when the liquid surface is at at fixed point 162 or 164 on the cylindrical float 36. The size of the increment is then equal to length of a facet.
The diameter of the wheel is based on the location of the axle 44 and the strength, density, and frictional properties of the magnetic material used for the facets. The axle 44, or center of rotation of the pinwheel, lies approximately on a vertical line through the center of gravity and center of bouyancy of the reference device so that the device will rise and fall vertically rather than bob on angle. In this way, the faces of the fiducials 46 and 48 will remain approximately perpendicular to the acoustic beam being transmitted up the tupe, thus ensuring strong and detachable acoustic reflections.
Two alternative embodiments of the quasi-static reference device shown in FIG. 7 are shown in FIGS. 10 and 11. The reference device in FIGS. 10 and 11 is identical to the one in FIG. 7, except that guide magnet 40 has been raised above the product level 162. The purpose of the guide magnet 40; is to help keep the reference device vertically aligned.
The actual location of this guide magnet 40 on the reference device can vary provided that it is not positioned where it will produce a detectable acoustic echo. The position of the guide magnet 40 shown in FIG. 7 is above the fiducial 46 but close enough to it that the system cannot complete the processing of the echo from the fiducial 46 in time to also detect and process the echo from the guide magnet; in other words, the system has enough to detect and process the echo from the fiducial 46 but not enough time to let the echo from the guide magnet 40 interfere. The guide magnetic 40 can also be positioned along the side of the cylindrical float at the very top, so that it is never submerged. When the guide magnet is positioned above the highest level that the liquid can rise, no echo is produced by the guide magnet. FIGS. 10 and illustrate other locations for the guide magnet. In FIGS. 10 and 11, the guide magnet 40 is fixed to the float and the pin wheel support, respectively, and aboove the highest level that the product may rise again, this means that it will not be; submerged and there is no possibility of an unwanted acoustic echo.
The guide magnet 40 in FIGS. 7, 10, or 11 is shown in detail in FIG. 12. It consists of magnetized solid cylinder 350 that is sallowed to move freely in a holder 41. This guide magnet is used primarily to help maintain vertical alignment when the reference device changes position. FIG. 12 shows side and front views. The guide magnet has a relatively thin horizontal dimension, so that it will adhere to the wall of the prove, which has a relatively small radius (a radius of 0.5 in. or larger). A thin, cylindrical magnet with the smallest coefficient of friction possible is the preferred embodiment because it will allow the reference device to roll vertically along the wall and slide horizontally to maintain vertical alignment with the surfce. Because the cylindrical magnet rolls on the tube wall, it can only transmit forces perpendicular, or normal, to the wall. Therefore, it produces no substantial vertical firctional forces that would effect the rotation of the pinwheel about the corners of the facets. An alterntive embodiment is shown in side, front, and top views in FIG. 13, where the cylindrical magent is replaced by a thin, small, rectangualr guide magnet 360. The rectangular embodiment will produce both fricitonal forces and forces normal to the tube wall, and its strength has to be carefully calculated to ensure proper functioning of the pinwheel. another embodiment is shown in side and front views in FIG. 14, where a small, ferromagnetic ball bearing 340 replaces the cylindrical magnet 350 of FIG. 12. The ferromagnetic ball bearing is magnetized by a magnet 342 placed in a nonmagnetic holder 41. The ball bearing is thus attracted to the metal wall of the tube and can roll either horizontally or vertically without transmitting any fricitnal forces. Regardless of the type, the guide magnet should be strong enough that the reference device does not separate from the wall of the tube during vertical travel. If this happens, the reference system could tilt and become wedged between the walls of the tube. If three or more equally spaced roller magnets are used along the circumference of the cylindrical float, vertical alignment can also be maintained and the possibility of the float getting stuck can be eliminated.
An alternative embodiment of the quasi-static reference device shown in FIG. 10 can be seen in FIG. 15, where the guide magnet 40 of FIG. 10 has been replaced by a second mangetized wheel 60. The second wheel 60 has a smooth magnetized circumference so that it can roll up and down the sides of the vertical mount 18 about its axle 62. The distance between the axle 62 and the sleeve 61 should be smaller than the smallest leve change to be measured, so that the float 36 can not bob up and down during a measurement. Although this alternative is quite similar to the embodiment illustrated in FIG. 10, it is not as desirable because its center of gravity is not as low, and therefore, it tends to not remain aligned as well.
The reference device will work the same way whether it is the pinwheel and guide that are magnetized and roll along a ferromagnetic surface, or whether, conversely, the pinwheel and guide are the ferromagnetic components and it is the surface that is magnetized (or has a magnet affixed to its length).
Some sliding of the reference device may occur when the liquid sufrace is immediately below or above the level at which the pinwheel will rotate. At this level, random fluctuations may initiate and then terminate a rotation at the fulcrum points 70 and 72 on the pinwheel device in FIG. 7. The amount of slippage, which might be on the order of several thousandths of an inch, will depend on the frictional force established at the fulcrum. With a high frictinal force, sliding can be minimized. Therefore, materials with a high coefficient of friction are used. A leak detection test should not be initiated when the product level is too close to this critical rotation level. This can be assessed by measuring the distance between the surfce and the upper fiducial. Unless this distnce is greater than some specified number, a leak detection test should not be initiated. This distance will differ for different types of liquid, but should be set so that a test can be started if the liquid level is within 80% of a facet-rotation threshold.
Proper functioning of the reference device requires that the axle have low friction and that the total distance between the pin 44 and the sleeve 43 in FIG. 7 be smaller than the smallest changes that have to be measured. In the present system, the total vertical movement has to be less than 1 distance-resolution cell.
Maintaining proper vertical alignment before, during, and after the reference device rises or falls rquires that its center of gravity be below its center of bouyance. The larger the separation, the truer the alignment.
The reference device is used for measuring the height of the product surfce in the tank and for testing a tank for leaks. Both the quasi-static and the fixed fiducials are required for the product-level measurements, but only the upper fiducial on the quasi-static reference is actually required for a leak detection test. The reference device remain permanently affixed to the wall during the entire leak detection test, which may take 1 to 8 h to complete, but it is not required to remain fixed during product-level measurements, which typical take less than a minute. A two-fiducial reference device that is allowed to float vertically in the tube and is not attached to the wall can also be used for the product-level measurement.
Returning to FIG. 7, and additional fiducial 48, spaced some distance from the first fiducial 46 by a rod 50, is required in order to develop an estimate of the speed of sound near the surface of the product. Fiducial 46, F 4 , is preferably positioned at a height, h 4 , that is at a distance, Δh 4-s , 1 to 2 in. from the surface 32 of the product. Fiducial 48, F 3 , is preferably positioned at a height, h 3 , which is at a distance , Δh 3-4 , 2 to 12 in. from fiducial 46. The product level itself is at the height, h s , above the transducer, and the transducer is located at a height, h o , above the bottom of the tank. With the acoustic echoes reflected from the surface of the product and from the various fiducials, it is possible to compensate for changes in the product level, h s , that are not caused by actual increases or decreases due to a leak, for example, those due to the thermal expansion or contraction of the prodcut over time. Unlike the prior art, the present invention does not require a series of evenly spaced fiducials in order to ensure a fixed fiducial is located near the product surface.
FIGS. 16 through 20 are alternative embodiments of the acoustic transducer and fixed fiducial systems. FIG. 16 is identical to FIG. 7 except that the fiducials 24 are affixed to the vertical mount, are thin bars positioned such that long axes are perpendicuar to the acoustic transducer 22. Four of many acceptable cross-sectional shapes 54, 64, 94, and 104 for the fiducials 24 and 26 are shown in FIG. 16. The triangular bar 54 has the preferred cross-section, because (1) the bottom edge of the bar is flat and perpendicular to the transducer so that the acoustic energy reflected from the fiducial is mazimized, and (2) the top edges of the bar are not perpendicular to the transducer and surface and will thus minimize the acoustic energy received from fudicials and surfaces located above it.
FIg. 17 is identical to FIG. 7 except that a fiducial 25, which is permanently affixed to the vertical mount, has been added between the downward-aimed transducer 23 and the bottom of the vertical mount 27. Either a cylindrical or a bar-type fiducial (i.e., one with a traingular, half-cylindrical or square cross-section) can be used for 25. If fiducial 25 is a bar type, a triangular cross-seciton 56 is the preferred configuration. Fiducail 25 is used to estimate the speed of sound through the product between the downward-aimed transducer and the water/product interface. The cylindrical fiducials 24 and 26 shown in FIG. 17 can be replaced by the bar-type fiducials 54, 64, 94, or 104 shown in FIG. 16.
The configuration of the transducer 22 and the fiducials 24, 25, and 26 shown in FIGS. 18 through 20 correspond to FIGS. 7, 16, and 17, respectively, except that the downward-aimed transducer 23 used to measure the water level in the tank is replaced by an upward-aimed transducer 33 located on the bottom of the probe's vertical mount. Since the bottom of the vertical mount 27 rests on the bottom of the tank, once the water level is greater than the thickness of the acoustic transducer, in FIGS. 18 through 20 the water/product interface will be between upward-aimed transducer 33 and a fiducial 29 or 25 located below the upward-aimed transducer 22, which is used to measure product level and do a leak detection test.
FIGS. 21 and 22 show alternative embodiments of the cylindrical float 36 and the fiducials on the quasi-static reference device 28 shown inFIG. 7. The float 36 and fiducials shown in FIG. 21 are identical to those in FIG. 7 except that an additional fiducial 47 has been added below fiducial 48. FIG. 22 is anarray of many fiducials hanging on a guide cable 80 below the float 36 and the fiducial affixed to the float 46. Only four conical fiducials 82, 84, 86, and 88 are shown in FIG. 22. The bottoms of all of the conical fiducials are perpendicular to the direction of the acoustic pulse, and the cross-sectinal area of each successive conical fiducial gets progessively larger from bottom to top; however, this change in corss-secitonal area is not required if proper gain control is used to collect the data. There is no limit to the number of fiducials that can be attached to the guide cable 80. More accurate estimates of the height of the product surface can be achieved with the additional fiducials in the configurations shown in FIGS. 21 and 22, because the speed of sound between the highest permanently affixed fiducial 26 and the surface can be estimated more accurately with more fiducials. If the length of the array in FIG. 22 extends from the surface to the bottom of the tank and if the number of fiducials on the array is sufficient, permanently affixed fiducials like 24 and 26 are not needed to measure the height of the surface or to perform a leak detection test. If only surface height measurements are required, then it is not necessary for the float to be rigidly attached to the wall with a magnet, and the floating fiducials in FIGs. 21 and 22 can be used as shown.
a. Product-level Measurements
An estimate of the sound speed between the transducer and the liquid surface is necessary for determining the level of the product in the tank. This estimate is made from measurements made by two or more of the four fiducials 24, 26, 48, and 46 found on the probe (FIG. 7). Two different analysis algorithms are used to estimate the speed of sound between the transducer and the surface. One algorithm uses the fiducials 46 and 48 on the reference device 28 and two fixed fiducials 24 and 26, and the other uses only the fixed fiducials 24 and 26. A third algorithm, which can be used regardless of the location of the transducer, is then used to compute the product level with either of these sound speed measurements. This algorithm gives accurate estimates of the liquid height, even if the transducer is covered with water. If the transducer is submerged in the water, and only one fiducial is used to estimate the sound speed, estimates of the height of the product surface can be highly erroneous. This is because the average speed of sosund through water (e.g. 14798 m/s at 25° C.) may be verry different from the average speed through the liquid in the tank (e.g., gasoline, which has a sound speed of 1147 m/s at 25° C.); thus the average speed of sound between the transducer and the fiducials may be significantly different from the average between the fiducial and the surface.
Product level is computed from estimates of the speed of sound between the upper fixed fiducial 26 and the surface. Two estimates are made, one using the two fiducials 24 and 26 fixed to the tube, and another using the two fiducials fixed to the reference device. The estimates from each pair of fiducials are averages. More specifically, the sound-speed estimate between the surface and the upper fixed fiducial, U 2-s , is calculated in inches per second from the equation
U.sub.2-s =(U.sub.1-2 +U.sub.3-4)/2=[((2Δh.sub.1-2)/(t.sub.2 -t.sub.1))+((2Δh.sub.3-4)/(t.sub.4 -t.sub.3)] (5)
where
U 1-2 =the speed of sound in inches/second between fiducials 24 and 26 permanently affixed to the vertical mount
U 3-4 =the speed of sound in inches/second between fiducials 46 and 48 affixed to the quasi-static reference device
Δh 1-2 =known distance in inches between fiducials 24 and 26 permanently affixed to the vertical mounts
t 2-1 =the difference in the round-trip travel times in seconds between the transducer and fiducial 26 and the transducer and fiducial 24
Δh 3-4 =known distances in inches between fiducials 46 and 48 afficed to the quasi-static reference
t 3-4 =the difference in the round-trip tavel times in seconds between the transducer and the fiducial 46 and the transducer and fiducial 48.
The height of the surface above the transducer in inches, h s , is then calculated from
h.sub.s =h.sub.o +h.sub.2 +U.sub.2-s (t.sub.2-s)/2 (6)
where
h o =height of the transducer above the bottom of the tank
h 2 =height of fiducial 26 in inches
U'd 2-s=average speed of sound used to estimate the speed of sound between fiducial 26 and the surface in inches/second
t 2-s =round-trip travel time in seconds between the fiducial 26 and the surface
The accuract of this method depends on the vertical profile of the temperature betgween the first fixed fiducial 24 and the surface (which may include strong temperature gradients immediately below the surface), the distance between the two fixed fiducials and the two fiducials on the reference device, the accuracy of the measurement of the distance between the pairs of references, and the accuracy of the acoustic system in measuring time. This method was evaluated under a wide range of temperature conditions with a prototype of the invention in an 8-ft-dimameter, 8,000-gal underground storage tank filled to 77 in. with gasoline. Rsults show that this method has a precision and accuracy surpassing 1/8 in.
An estimate of the speed of sound between the upper fixed fiducial and the surface can also be made using only the two fixed fiducials 24 and 26. If the distance between the fiducials and the transducer is great, an estimate of sound speed made with two fiducials produces a more accurate estimate of height than one made with a single fiducial. This is because strong gradients in temperature tend to cause overestimation when the average sound speed is measured with a single fiducial. These strong gradients, which are found near the bottom of the tank, do not affect the estimate of sound speed made with the two fixed fiducials, because they occur only in the region below the fiducials. More specifically, the sound speed estimate between the surface and the upper fixed fiducial, U 2-5 , in inches per second is calculated from
U.sub.2-3 =U.sub.1-2 =(2Δh.sub.1-2-)/(t.sub.2 -t.sub.1).(7)
The height of the product is then determined from Eq. (6).
FIG. 1 illustrates a variety of temperature profiles that may be encountered in the product in an underground storage tank. FIG. 23 (a) is a sound-speed profile measured in a gasoline tank filled to 78.7 in. The sound-speed profile is estimated directly from the temperature profile in FIG. 23(b) by means of the following empricially derived relationship for gasoline:
U=-4.45T+1258.45 (8)
U=sound speed in meters/second
T=temperature in degrees Centigrade
The sound speed at the location of the two fixed fiducials 24 and 26 and the two quasi-static fiducials 46 and 48 is shown in FIG. 23 (a). The actual sound speed between the second fixed fiducial 26 and the surface (as well as the sound speeds between any two points on the profile) was estimate by integration of the sound-speed profile. The true average sound speed (true U 2-s ) between the second fixed fiducial and the surface is shown as the solid box in FIG. 23 (a). The open box is the sound speed between fiducials 24 and 26 that is calculated using Eq. (7) and the open circle is the sound speed estimated from fiducials 24, 26, 46 and 48 with Eq. (5). The true sound speed between the transducer and the surface is denoted by the plus sign. In this temperature profile, the error in measuring the surface height from Eqs. (6) and (7) is 0.03 in.
b. Water-level Measurements
As shown in FIG. 7, the level of the water 33 in the tank is measured by the downward-pointed transducer 23, which emits an acoustic pulse that is reflected from the water/product interface. The speed of sound through the product between the transducer and the water/product interface, which is required to convert the round-trip travel time to distance, is measured by the upward-pointing transducer 22, which emits an acoustic pulse that is reflected from the lower fiducial 24 (which is a known distance from transducer 22). The speed of sound estimated with this lower fiducial is sufficient to meet the 1/8-in. accuracy requirement providing that the fiducial 24 is located within approximately 6 to 12 in. of the upward-pointing transducer. Alternatively, as shown in FIG. 17, a fixed fiducial 25 can be located between the downward-pointing transducer and the maximum water level. In both configurations, the water can be measured at any level from the bottom of the tank up to approximately 4 in. The level of the water above the bottom of the tank, h w , in inches is calculated from the following algorithm:
h.sub.w =h.sub.h -[t.sub.w-p U.sub.1 /2] (9)
where
h b =the distance between the bottom of the tank and acoustic transducer 23 in inches
t w-p =the round-trip travel time between the transducer 23 and the water/product interface in seconds.
U 1 =the speed of sound through the product between the transducer and the water/product interface (1) estimated from a temperature measurement of the product, (2) measured between the transducer 22 and the nearest fiducial 24 affixed to the vertical mount, or (3) between the transducer 23 and the nearest fiducial 25 affixed to the vertical mount
Alternatively, the lower transducer can be mounted below the water/product interface and pointed upward (33 in FIGS. 18 through 20). With this approach, the water level cannot be measured when it is below the transducer, i.e., near or at the bottom of the tank. The minimum depth that can be measured is controlled by the thickness of the transducer and the interference of the acoustic reflection from the water/product interface with the transmitted pulse.
An alternative algorithm can be used to measure water level without the acoustic reflection from the water/product interface. This approach can be used when the water/product interface cannot be detected, or as a stand-alone measurement. It requires that the acoustic reflection from the bottom of the probe 27, which is located at a known distance from the transducer, be measured. The approach can be implemented with the downward-pointed transducer shown in FIGS. 7, 16 and 17, or with the upward-pointed transducer shown in FIGS. 18 through 20, which is submerged in water, by means of the following algorithm, which is used to calculate the height of the water above the bottome of the probe, h w-pb :
h.sub.w-pb =[pb-(U.sub.1 t.sub.pb /2)]/[1-(U.sub.1 /U.sub.w)](10)
where
h pb =the distance between the bottom of the tank and acoustic transducer 23 in inches
t pb =the round-trip travel time between the transducer and the reference bottom of the probe in seconds
U w =the speed of sound through water.
The height of the water above the bottom of the tank can be calculated by adding the distance between the bottom of the probe, which reflects the acoustic pulses, and the bottom of the tank to h w-pb calculated by Eq. (10).
The accuracy of this indirect water-level measurement concept depends primarily on the accuracy of the estimate of the sound speed in both the product and the water. The estimate of the speed of sound through the product is made from the fixed fiducial 24 in FIGS. 7, 16, 18 and 19 or fiducial 25 in FIGS. 17 and 20, and the estimate of the speed of sound through water is made from the well-known relationship between sound speed and temperature, available from published sources. This relationship is used in combination with an estimate of the temperature made by a sensor 19 in FIG. 7. The speed of sound through water, U w , in m/s is estimated from
U.sub.w =1498+2.4T (11)
The temperature sensor 19 located near the bottom of the probe assembly is used to estimate T in Eq. (11).
c. Leak Detection Test
The product in a tank (as well as the tank itself) is continually expanding or contracting in response to temperature. This causes changes in the product level that are not due to leaks. To find small leaks, therefore, the product-level changes due to thermal expansion and contraction must be compensated for. During a leak detection test, the upper fiducial 46 on the reference device 28 and either the lower or upper fixed fiducial (24 or 26) usually located in the bottom third of the tank are ued to calculate a temperature-compensated level change (volume change) with sufficient accuracy to meet or exceed the EPA standards for an ATG or tank tightness test. An array of fiducials can be used to calculate an average product temperature that is weighted according to the cross-sectional area of the tank (i.e., a volumetrically weighted average). Although one can meet the EPA regulation with only one fiducial, additional accuracy can be obtained by using more.
The largest errors encountered by acoustic measurement systems such as the present invention are due to improper weighting of the large temperature changes that occur near the bottom and top of the tank, and erroneous estimates of the sound speed between the surface and the fiducial closest to the surface. The present invention addresses both problems. It is not necessary to known the height of the reference device above the transducer in order to perform a leak detection test. However, the position of the fiducial on this device must remain at a fixed height as close to the surface as possible during the test. The primary function of the reference device in a leak detection test is to provide this fixed location for the fiducial.
The round-trip travel time is calculated from the acoustic echoes reflected from the surface, one of the fixed fiducials (e.g., 26), and a fiducial on the reference device (the one closest to the surface 46). The temperature-compensated level changes measured in inches, δh s , are calculated from ##EQU4## where U=spedd of sound in meters/second between the transducer and the surface which can be estimated (1) between fiducials 46 and 48, (2) between fiducials 24 and 26, (3) between the transducer and fiducial 24, or (4) between the transducer and fiducial 26, or with an average or weighted average of any combination of these,
δt s =change in the round-trip travel time over the measurement period in seconds between the transducer and the surface
δt r =change in the round-trip travel time over the measurement period in seconds between the transducer and a fiducial such as 46, which is rigidly fixed to the vertical mount
V=volume of the product in the tank in inches 3 at the height of the surface of the product in the tank
h=height of the liquid surface in the tank above the acoustic transducer in inches
A=cross-sectional area of the surface in inches 2 of the product in the tank at the height of the surface of the product above the bottom of the tank
C e =coefficient of thermal expansion of the liquid in the tank
t s =round-trip travel time between the transducer and the surface in seconds
ΔT=change in the average weighted temperature between the transducer and the fiducial 46 that is located closest to the surface and affixed to the vertical mount during the measurement and ##EQU5## ps where W 1 =volume of the product in the tanke below fiducial 24 or fiducial 26 divided by the total volume of the product in the tank
W 2 =the volume of the product between fiducial 24 or fiducial 26 and the surface divided by the total volume of the product in the tank=1-W 1
δt 1 v 2 =change in the round-trip travel time between the transducer and either fiducial 24 or 26 in seconds
δ 4-1 v 2 =change in the round-trip travel time between fiducial 46 on the quasi-static reference device and either fiducial 24 or fiducial 26
t.sub.(1 v 2) =round-trip travel time between the transducer and either fiducial 24 or 26
U.sub.(1 v 2)=sound speed between the transducer and either fiducial 24 or 26
U 2 =sound speed between the transducer and fiducial 26 ##EQU6## An estimate of the average temperature change is made from ##EQU7## where t r is the round trip travel time between the transducer and fiducial 46 on the quasi-static reference device.
The first term in the square brackets in Eq. (12), δt s , is a measurement of the product-level changes. The second term, δt r , is used to correct the level changes for errors in sound speed, and the third term, involving ΔT, is the one that compensates for the thermal expansion and contraction of the product produced by temperature changes in the product. If a fixed fiducial is not located within 2 to 3 in. of the surface, the sound-speed correction for level changes in the second term can be significantly in error relative to the leak detection performance standards specified by the EPA. Due to the heat transfer between the liquid and the vapor found immediately above the surface, temperature and sound speed can change significantly in the upper 12 in. of the product. The reference device 28 minimizes this error because it always positions a fiducial within 2 to 3 in. (or less) of the surface. Temperature compensation is accomplished in the third term. In the present embodiment, the temperature is weighted only by two fiducials. In large tanks, or others in which more accurate compensation is required, additional weighting may be necessary. This is accomplished by means of one or more additional fixed fiducials or the fiducials in FIGS. 21 or 22, which are separated by a known distance. With the present invention, the bottom two fixed fiducials 24 and 26 can be used in conjunction with the fiducial 46 for temperature compensation as described by ##EQU8## where U 1-2 =the sound speed estimated between fiducials 24 and 26
U 2-5 =the sound speed estimate between fiducial 26 and the surface using Eq. (5)
W 1-2 and W 2-s =the volume of product between fiducial 24 and 26 and fiducial 26 and the surface, respectively, divided by total volume of product in the tank.
An alternative yet similar equation that can be used to estimate the temperature-compensated level changes is ##EQU9## The only difference between Eqs. (12) and (16) is the term that is used to correct the level changes for sound speed. Once the speed of sound through the layer of product between the transducer and the upper fiducial 46 on the reference device has been estimate, the quantity (C 1 ) in Eq. (16) is a constant used to extrapolate the estimate to the layer of product between this fiducial 46 and the surface. Another method of estimating the δh s is to use the sound speed measured with the two fiducials on the reference device to estimate the sound speed between fiducial 48 and the surface, as given by ##EQU10## where U 3-4 =speed of sound between fiducials 46 and 48.
d. Alternative Embodiments of the Quasi-Static Reference Device
FIGS. 24 through 26 illustrated three alternative embodiments of the quasi-static reference device that do not rely on a magnetized wheel but nevertheless operate on the same basic principles. All three are variations on the "woodpecker" embodiment of the reference device, as opposed to the "pinwheel" embodiment previously discussed. FIG. 24 shows a reference device 128 having a vertical cylindrical float 136, a fiducial 146 (corresponding to fiducial 46 in FIG. 7), and a fiducial 148 (corresponding to fiducial 48) spaced some distance from fiducial 146 by a rod 150. As the liquid level goes up (or down), the reference device detaches itself from the wall and reattaches itself at a higher (or lower) location. Thus, with the nominal product level 160, the following sequence occurs: the device attaches itself to the wall; there is an interval during which the product level goes down; the device then pulls away from the wall; the cycle is repeated with each incremental change in product level. The device is designed so that the difference in product level at the beginning (160) and end (162 or 164) of this interval, shown in FIG. 24, is generally between 0.25 and 0.5 in. The fiducial 148 and the rod 150 are not essential. Toward the top of the reference device 128 are two fulcrums 170 and 172 and a permanent magnet 174. The upper and lower fulcrums on this embodiment and on the ones shown in FIG. 25 and 26 are made of a material that has a high coefficient of friction with the steel tube. As with the pinwheel device, when a drop in the product level occurs that is sufficient to create a moment about the fulcrum 170 that breaks the bond between the magnet 174 and the wall 18, the woodpecker device rotates about the fulcrum 170, drops to the new level, and reattaches itself to the wall by the pull of the magnet 174. Conversely, the device moves up the tube if the liquid level rises. The woodpecker device, like the pinwheel, stays rigidly affixed to the wall during a leak detection test, because the product-level changes that occur during a test are not large enough to cause the device to move. The weight of the various components of the reference device 128 are such that the center of gravity of the reference device is below its center of bouyancy regardless of the level of the product in the tank. This keeps the reference vertiacally aligned with the surface and the transducer, even when the reference is released from the wall, drops or rises, and then reattaches itself to the wall. Otherwise, the reference would have a tendency to float horizontally on its side instead of vertically. The rod 150 can be a j hollow plastic rod, with can be filled with a heavy material such as steel or lead shot 152, so that it will have the force and moment balances required for proper functioning of the reference device 1285. Adding weight at the bottom of the rod 150 ensures that the center of gravity of the reference device is as low as possible.
An analysis of the static forces and moments acting on this reference device shows the important design features that must be specified for the reference device to drop or rise at predetermined incremental steps. It was assumed that the net vertical force obtained from the sum of the gravity and bouyancy forces always act at a fixed distance δ x from the fulcrum, even though this distance will increase slightly when the reference device begins to rotate about the fulcrum; this distance would not change if the float and fiducials were suspended from a pin and axle as done with the pinwheel. The analysis shows that the following two conditions must be satisfied in order for the reference device to function properly with regard to downward movement:
α>δ.sub.y /δ.sub.x (18)
where α is the coefficient of friction between the fulcum and the wall, δ y is the vertical distance between the fulcrum and the magnet, and δ x is the horizontal distance between (1) the contact point of the vertical wall 18, fulcrums 172 and 170, and the magnet 174, and (2) the location of the center of gravity of the net sum of the gravitational and bouyancy forces on the reference device, F net , and
F.sub.net ≦[F.sub.m (δ.sub.y /δ.sub.x))=αF.sub.m ](19)
where F m is the force holding the magnet to the wall of tghe tube. Eq. (18) shows that the minimum distances between (1) the fulcrum and the magnet and (2) the wall and the center of gravity of the net force on the reference device depend on the coefficient of friction between the wall and the fulcrum. Eq. (19) shows the relationship between the strength of the magnet and the net force on the reference device, so that when the device breaks away from the wall it will rotate about the fulcrum rather than slide down the side of the tube. If α=0.1 and δ x =0.75 in., then δ y ≦0.075 in., which means the fulcrum is very close to the magnet. If these conditions are satisfied, the reference device will not slide down the wall but will drop incrementally. Because of the frictional force generated between the fulcrum and the wall, the reference device will remain attached to the wall unit the magnet is completely detached from the wall. Proving that Eqs. (18) and (19) are satisfied, the higher the coefficient of friction between trhe fulcrum 170 or 172 is, the better the performance of the reference device. The higher friction tends to keep the reference device attached to the wall, even when the balance of forces, which create the moment about the fulcrum, are just at the instant of producing the rotation. This higher friction offsets the fact that the magnet, if it has any surface area, does not detach itself from the wall all at one time. The rotation begins as soon as any part of the magnet pulls away from the wall.
The alternative embodiments of the woodpecker reference are shown in FIGS. 25 and 26 without detailed explanation, because they are substantially similar to the one shown in FIG. 24 and described above.
FIGS. 27 -f show seven embodiments of the magnet and fulcrum stepup. However, any combination of fulcrum and magnet shapes can be made to operate functionally as described above. In FIG. 27a the magnet is rectangular in shape, with the vertical dimension 300 being much smaller than the horizontal dimension 314, and the fulcrums are triangular, with only the tip of the triangle 310 touching the wall. The smaller the vertical dimension of the rectangle, the easier the system is to design. This is the preferred embodiment, because the reference tends to stay better aligned vertically as it moves up and down. This embodiment works best with a vertical support 12 that presents either a flat or a nearly flat wall (one with a very large radius). In a tube of small diameter, such as the 1.5-in.-diameter tube 12 used in the preferred embodiment, only the ends of the magnet and fulcrums actually touch the wall of the tube. In another embodiment, shown in FIG. 27b, the triangular fulcrum has been replaced with a rectangular one whose vertical dimension, like that of the magnet, is smaller than its horizontal dimension. This configuration functions in the same way as the one in FIG. 27a, because once the reference device begins to rotate about the fulcrum, the rotation occurs at the edge of the rectangle. This alternative is used if better contact is needed between the wall and the fulcrum than is provided by the triangular embodiment. In FIG. 27c, the fulcrums and the magnet all have a triangular shape. In FIGS. 27d and e, the wide rectangular magnet in FIG. 27a has been replaced by one whose vertical dimension is greater than its horizontal dimension. The embodiments in FIGS. 27f and g can be used when the tube 12 has a small radius. In FIGS. 27f and g, the magnet is rectangular in shape and the fulcrums are either rectangular or triangular in shape, with the horizontal dimension of both the magnet and fulcrums that is smaller than or approximately equal to the vertical dimension. The reference device will function properly regardless of the shape of the shape of the magnets and fulcrums, so long as the constraints given by Eqs. (18) and (19) are satisfied.
FIGS. 28 through 30 show some additional alternative embodiments of the fulcrum and magnet configuration. They are similar to the embodiments shown in FIGS. 24 through 26.
The fulcrums used in all of the embodiments of the reference device can also be replaced by magnets of similar shape. This alternative is used if the vertical support 12 is not perpendicular to the surface of the product. An analysis similar to the one performed for the nonmagnetic fulcrum shows the conditions that must be satisfied for this reference device to function in the same way as the one with a nonmagnetic fulcrum. The two are very similar, as can be seen by comparing Eqs. (18) and (19) with those below. The two criteria that must be satisfied for the reference with magnetic fulcrums to function properly with regard to downward movement are:
α≧[δ.sub.y /δ.sub.x ][1/((F.sub.f /F.sub.m)+1)](20)
where F f is the magnetic force holding the fulcrum to the wall, and
F.sub.net ≦[(F.sub.m (δ.sub.y /δ.sub.x))=αF.sub.m ]. (21)
If F f =F m , Eq. (21) shows that α≧0.5[[δ y /δ x ]]. If the strength of the magnet at the fulcrum 170 or 172 in FIGS. 24 through 26 is only 10% of the strength of the magnet at 174, Eq. (20) shows that α≧0.909[[δ y /δ x ]], or nearly the same as the relationship for a nonmagnetic fulcrum.
The reference device 28 does not have to be in a tube 12 such as the one described in the preferred embodiment (FIG. 7). It can be placed directly in the tank as long as there is a guide, such as a flat plate (FIG. 31) or channel (FIGS. 32 and 32), along which it can move. Such a guide might even be placed within a tube 12. The guide 312 shown in FIG. 31 is simply a long, thin, flat rectangular staff that can be inserted into a tube. FIG. 32 is a channel with sides 320 that are designed to keep the reference from wandering off a flat or curved surface. FIG. 33 illustrates a channel with a holder 330 that serves as a track for the reference device.
All embodiments of the woodpecker device are attached to a wall or tube mount by a permanent magnet. The wall or tube mount must be co nstructed of a metal with ferromagnetic properties so that the magnet 174 that will be attacted to it.
As was the case with the pinwheel, the woodpecker device will work the same way regardless of which components are magnetized: the magnets can be replaced with ferromagnetic material if the metal tube or vertical mount is a magnet or is magnetized.
Two additonal embodiments of the quasi-static reference device 28, using a variation of the woodpecker devices shown in FIGS. 24 through 26, are shown in FIGS. 34 and 35. These embodiments are obtained by attaching the magnet and fulcrum setup to the float and fiducial subsystem with a pin and axle by a rigid bar. The rotation of the bar is limited to a small angle, usually less than 30°, so that the magnet will reattach itself to the mount after the device has fallen or risen. The bar is physicall limited from rotating beyond a certain angle. These embodiments drop and rise similarly to the woodpecker device except the float and fiducials, which are hanging from the pin and axle, remain vertical during a drop or rise of the device because the float and fiducials are free to rotate at the pin an axle. The static analysis done for the woodpecker device also describes this embodiment.
Another general embodiment of the quasi-static reference device is one in which the permanent magnet is replaced by an electromagnet that is operated either by a battery (with a timer on the reference device itself) or by a power supply (at the ATG controller or system controller) connected to the cylindrical float by wires or by remote transmitters and receivers. In the latter configuration, the reference device would be instructed by the controller to attach or detach itself from the wall wheneer the surface of the product level changed by a specified amount. There could be several modes of operation. One would be to keep a current running through the electromagnet so that the reference device remained attached to the metal wall. When the level changed by a certain amount, the current would be turned off so that the reference device could rise or fall, and then, at the appropriate moment, turned on so that it would reattach itself to the wall. In the second mode of operation, the permanently magnetized wall would be the polar opposite of the permanent magnet. An electomagnet would then be used in conjunction with either the wall or the permanenet magnet; the electromagnet would change the polarity of the permanent magnet so that the wall and the permanent magnet would repel one another and allow the reference device to rise or fall when so instructed by the controller. The third mode of operation is similar to the second. In this mode, the reference device would have a permanent magnet, and the tube would not have to magnetized. A configuration would consist of a torroidal electromagnet that is placed outside the tube, floats with the product, and can be activated to produce a magnetic field with a polarity opposite to that of a power supply located at the ATG or system controller. It would be operated identically to the second mode. In the latter two modes of operation, the electromagnet is operated only when the reference device must be detached from the wall (i.e., when the product level changes). The power requirement is less for the latter two modes than it is for the first.
If a battery is used to power the electromagnet in the first mode, a timer must be used as a means ofdetermining when the float should attach and/or detach itself from the wall. Since the reference device has to be rigidly affixed to the wall only during a leak detection test, the timer can be used to set the precise hour to start and end a test.
Although the present invention has been described in terms of specific embodiments, it is anticipated that alterations and modifications will become apparent to those skilled in the art. It is therefore intended that the followign claims be interpreted as covering all such alterations and modifications as fall within the true spirit and scope of the invention. | 4y
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BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention relates to metallurgical processes and apparatus, and more particularly to metallurgical processes and apparatus in which metal chips are melted in a molten metal vortex which is fed by an inert gas bubble-actuated molten metal pump.
[0003] 2. Technical Background
[0004] My following U.S. patents disclose various apparatus and processes related to the introduction of metal chips into the charge-well of a metal melting furnace and the conveyance of molten metal from one place to another within or out of a metal melting furnace.
[0005] U.S. Pat. No. 4,710,126 discloses a process for producing dry metal chips. This process includes the steps of entraining fluid-containing metal chips in a gas, introducing the gas into a cyclone separator having an internal wall heated to fluid-vaporizing temperature by combustion in a surrounding chamber, purging and vaporizing fluid from said chips, exhausting hot gases and exiting dried metal chips from said separator, conducting hot gaseous products of combustion from the combustion chamber to a continuous centrifuge, extracting extractable fluid from starting metal chips in the centrifuge, entraining the chips in the hot gaseous products of combustion introduced into the centrifuge, and conducting the gaseous products with entrained chips from the continuous centrifuge to the cyclone separator, thereby providing an essentially closed system. The combustion chamber may be a part of an afterburner furnace and hot gases entraining vaporized oil exhausted from the cyclone separator may be recycled and employed as fuel for the combustion chamber.
[0006] U.S. Pat. No. 4,721,457 discloses a process for producing dried and cleaned metal chips by entraining metal chips in a gas, introducing the gas into a cyclone separator having a wall heated to fluid-vaporizing temperature by combustion effected in a surrounding chamber, purging fluid from said chips, exhausting hot gases and exiting dried metal chips from said separator, conducting hot gaseous products of combustion from the combustion chamber to a continuous centrifuge, extracting extractable fluid from starting metal chips, which may be previously uncleaned and/or unwashed, in the centrifuge, entraining the chips in the hot gaseous products of combustion introduced into the centrifuge, and conducting the gaseous products with entrained chips from the continuous centrifuge to the cyclone separator, thereby providing an essentially closed system. The combustion chamber may be a part of an afterburner furnace and hot gases entraining vaporized oil exhausted from the cyclone separator may be recycled and employed as fuel for the combustion chamber. Provision is made in the system for hot water and/or steam from either an external source of from a water jacket around the cyclone separator, preferably together with solvent and/or detergent, and a final chip drying step wherein the drying is effected using products of combustion which are en route back to the continuous centrifuge.
[0007] U.S. Pat. No. 4,872,907 discloses an apparatus and method for charging metal chips into a molten bath of the metal from which the chips are formed, comprising a compacting extruded and a delivery conduit which is resistant to the mass of molten metal and which is pivotable to dip into the molten metal bath when chips are being charged thereinto and out of contact with the bath when charging is to be discontinued, are disclosed. The chips are forced through the delivery conduit in the form of a compacted or densified mass preferably having a density between about 30 and 60 percent of the density of the solid metal and preferably between about 55 and 80 pounds per cubic foot. Feed is continued while the delivery conduit is in the molten metal bath and until it is removed therefrom to prevent entry of molten metal into the delivery conduit. The method is preferably conducted on a continuous basis and various sensors with appropriate wiring may be employed for safety and for making the method substantially automatic in operation.
[0008] U.S. Pat. No. 5,203,910 discloses a method for the conveyance of molten metal from one place to another, in a high-temperature molten metal pool in a metal-melting furnace or out of said molten metal pool, employing an at least partially-inclined elongated conveying conduit and gas feed means for feeding inert gas into the lower end of the conveying conduit and thereby inducing a flow of molten metal in and through said conveying conduit, is disclosed, along with suitable apparatus for carrying out the said method wherein the parts or elements coming into contact with the high-temperature molten metal pool are of a suitable refractory material.
[0009] U.S. Pat. No. 5,211,744 discloses a process for utilization of metal chips, especially scrap metal chips, particularly brass and aluminum, by introduction of the metal chips into a pool of molten metal of which they are formed or an alloy thereof. The process allows for minimization of fuel cost, heat loss, and minimal conversion of the metal at the surface of the molten metal pool to metal oxide, as well as an increase in the yield of utilizable metal from the remelting or recycling operation, by maintaining a non-oxidizing atmosphere at the surface of the molten metal pool and optionally utilizing vaporized residual impurities from chips being recycled such as oil, lacquer, or similar vaporizable impurity to assist in maintaining the non-oxidizing atmosphere. Elimination of impurity-removal steps previously required for preparation of the chips for recycling by introduction into such a molten metal pool is eliminated. Environmental pollution is also conveniently and simultaneously substantially reduced from vaporizable contaminants, fumes, and decomposition products of combustion thereof.
[0010] U.S. Pat. No. 5,395,424 discloses a method for the conveyance of molten metal from one place to another, in a high-temperature molten metal pool in a metal-melting furnace or out of said molten metal pool employing at least a partially-inclined elongated conveying conduit and gas feed means for feeding inert gas into the lower end of the conveying conduit is employed. A flow of molten metal in and through said conveying conduit, is disclosed, along with suitable apparatus for carrying out the said method wherein the parts or elements coming into contact with the high-temperature molten metal pool are of a suitable refractory material. According to the present invention, an intermittent or pulsating inert gas feed is employed to produce essentially spherical or cylindrical bubbles within the conveying conduit, thereby resulting in greater efficiency and economy because of the possibility of reducing the quantity of inert gas employed to induce the flow of an identical amount of molten metal.
[0011] U.S. Pat. No. 5,407,462 discloses a mass flow gravity feed furnace charger comprises a vertically-oriented elongated hollow conduit which is associated with an apertured heat-resistant charge-well cover adapted to lie essentially in contact with the upper surface of a molten metal pool in the charge well of a metal-melting furnace. Presized scrap metal charged into the conduit collects atop the surface of the molten metal pool, since the bottom opening of the conduit communicates with the charge-well cover aperture and permits the metal scrap to fall by gravity directly into the molten metal in the charge well. When the weight of the metal scrap column is sufficient to offset the resistance of the upper surface of the molten metal pool, the weight of the collected metal scrap gravitationally forces it into the molten metal mass it melts and is assimilated. Employment of the method and charge of the invention enables the controlled introduction of metal scrap by mass flow and gravity feed directly into and beneath the surface of the pool of molten metal and obviates numerous disadvantages and inconveniences of past practices.
[0012] U.S. Pat. No. 5,468,280 discloses a method for the conveyance of molten metal from one place to another in a high-temperature molten metal pool in a metal-melting furnace or out of said molten metal pool. At least partially-inclined elongated conveying conduit and gas feed means for feeding inert gas into the lower end of the conveying conduit is employed. A flow of molten metal is thereby inducted in and through said conveying conduit, is disclosed, along with suitable apparatus for carrying out the said method wherein the parts or elements coming into contact with the high-temperature molten metal pool are of a suitable refractory material. The inert gas is fed into the conveying conduit at a supersonic velocity, thereby simultaneously effecting a degassing of the molten metal while it is being conveyed.
[0013] U.S. Pat. No. 5,735,935 discloses an inert gas bubble-actuated molten metal pump which is located in a metal-melting furnace to effect circulation of molten metal throughout the furnace. The inert gas employed to actuate the molten metal pump is captured beneath a heat-resistant and flame-resistant cover located above the exit port of the pump and over a substantial portion of the molten metal to thereby to prevent splashing, spattering and disruption of a thin protective layer or skin of oxidized metal at the surface of the molten metal as well as to provide a non-oxidizing atmosphere at the surface of the molten metal beneath said cover. In this manner the inert gas is employed efficiently and economically.
[0014] U.S. Pat. No. 5,853,454 discloses a mass flow gravity feed furnace charger apparatus includes a charge-well cover having an aperture and an essentially vertical conduit for forming a substantially vertically-oriented column of metal chips or scrap within and above the aperture, and structure for bringing both the cover and conduit into position above a charge-well. The conduit is rapidly movable up and down to force the metal chips or scrap into molten metal in the charge-well even when the dross level at the surface of the molten metal is considerable, so that the apparatus and corresponding methods permit charging when gravity feed alone is not sufficient or sufficiently rapid. In a preferred embodiment, the conduit has an interior surface provided with gripping means to assist with the downward movement of metal chips or scrap into the molten metal in the charge well when the up and down motion of the conduit is in effect.
[0015] U.S. Pat. No. 5,919,283 discloses an inert gas bubble-actuated molten metal pump is located between one section of a metal-melting furnace and a second section to pump molten metal form the one section, wherein the molten metal is at a higher temperature, into the second section, wherein the molten metal is at a lower temperature, and its effluent is directed into contact with metal chips being charged into the second section, thereby assisting in the more rapid melting of the chips into the molten metal mass in the second section. The inert gas employed to acturate the molten metal pump is captured beneath a heat-resistant and flame-resistant cover located above the exit port of the pump and over a substantial portion of the molten metal mass in the second section, thereby providing a non-oxidizing atmosphere at the surface of the molten metal mass or pool beneath said cover. In this manner the inert gas is employed not only to actuate the inert gas bubble-actuated molten metal pump, but also to assist in the rapid melting of metal chips being charged, as well as to provide a non-oxidizing atmosphere at the surface of the molten metal.
[0016] U.S. Pat. No. 5,984,999 discloses an arrangement in which the vortex well of a metal melting furnace is provided with an internal cavity having a circular cross section when viewed from the top, preferably a cavity of cylindrical or conical configuration, and with a peripheral exit port located tangentially with respect to said cavity at a lower level thereof for exit of molten metal into the main chamber of the furnace. An inert gas bubble-actuated molten metal pump brings molten metal from a hotter section of the furnace, advantageously directly form the main chamber, and has its exit port located tangentially to the periphery of the cavity at an upper level thereof, thereby creating vortical flow of molten metal therein and for circulation of hotter molten metal throughout the furnace. A head of molten metal can be created in the vortex well, which advantageously has an exit port of restricted internal cross-sectional area, to assist with attainment of these objective. A heat and flame-resistant cover may be located above the cavity and advantageously has an aperture therein for the loading of metal chips or scrap thereinto. A gravity-feed chip charger may surmount the aperture for the discharge of new metal chips or scrap into the cavity through the said aperture.
[0017] U.S. Pat. No. 6,068,812 discloses an inert gas bubble-actuated molten metal pump, for the movement of molten metal in a molten-metal bath, which obviates the necessity of a heat proof and flameproof cover to counteract splashing and spattering at the surface of the molten metal bath above the pump, comprising an inert gas diffusion means at an upper end thereof, the diffusion means having an upper surface containing a multiplicity of small upwardly-opening apertures for the breaking up of large bubbles and the diffusion of small bubbles of inert gas upwardly therethrough. The pump includes a refractory block which comprises a conveying conduit which is preferably elongated in width and a spreader cavity in communication with both a passageway in the block for providing a source of inert gas and a lower end of the conveying conduit.
[0018] My above referenced patents are incorporated herein by reference.
[0019] The purpose for creating a vortex in the vortex well is to rapidly submerge the small particles of metal whose mass would otherwise prevent the particles from penetrating the surface tension of the molten metal bath, thus causing a substantial increase in the percentage of metal loss due to oxidation. It has, however, has been determined that further steps must be taken to reduce oxidation, particularly when relatively more expensive metals such as aluminum are being used.
SUMMARY OF THE INVENTION
[0020] It is an object of the present invention to provide a means for further reducing metal losses due to oxidation in the vortex molten bath.
[0021] It is another object of the present invention to provide a way of integrating the functions of circulating molten metal and submerging metal chips in molten metal vortex to allow for rapid recovery of any temperature drop which may result from the introduction of the cold scrap.
[0022] It is still another object of the present invention to provide a means for efficiently burning off volatile hydrocarbons which may be present with metal chips that are being melted.
[0023] These and other objects are attained by the present invention which is a metal melting closed furnace which includes a main chamber, a circulation well connected to the main chamber by a communications passageway and a vortex well having an exit outlet for molten metal into the main chamber. A cover or other suitable containment means is emplaced above the vortex well. An inert gas bubble activated molten metal pump is provided in which there is an entry port in the circulation well and exit port tangentially arranged with respect to the periphery of the cavity. This exit port will typically be at or near the top of the vortex well. In order to reduce oxidation, inert gas bubbles are captured from the discharge of the molten metal pump, creating an inert gas atmosphere or blanket above the molten metal vortex so that this inert gas atmosphere is continuously or intermittently replenished.
[0024] Also encompassed by the present invention is a process for melting metal in a furnace in which molten metal is heated in a main chamber and then circulated to a circulation well. The molten metal is then moved from the circulation well by an inert gas bubble actuated pump to the vortex well. An inert gas atmosphere is formed below the cover and is continuously or intermittently replenished by inert gas from the bubbles in the pump.
[0025] Also encompassed by the present invention is a metal-melting furnace which includes a main chamber and a circulation well connected to the main chamber by a communication passageway. There is also a vortex well having periphery, a top and an exit outlet for recovering molten metal therefrom, and a cover is emplaced over the vortex well. On occasion, the vortex well is the circulation well. The furnace also includes an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well, wherein the exit port is positioned at a vertical position which is higher than the entry port. There is also an inert gas atmosphere positioned in the vortex well above the surface of molten metal.
[0026] Also encompassed by the present invention is a metal-melting furnace which includes a main chamber and a circulation well connected to the main chamber by a communication passageway. There is also a vortex well having a periphery, a top and bottom exit outlet for recovering molten metal therefrom, and a cover or other containment means is emplaced over the vortex well. The furnace also includes an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well. There is also an inert gas atmosphere positioned in the vortex well beneath the cover.
[0027] Also encompassed by the present invention is a metal melting furnace which includes a main chamber and a circulation well containing molten metal having a surface level connected to the main chamber by a communication passageway. There is a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom, and a cover is emplaced over the vortex well. The furnace also includes a sensor for measuring the surface level of the molten metal in the circulation well and a means for stopping feed to the vortex well to prevent over filling of the furnace.
[0028] Also encompassed by the present invention is a metal-melting furnace which includes a main chamber and a circulation well connected to the main chamber by a communication passageway. There is also a well block having, a vortex well, said vortex well having a periphery, top and an exit outlet for recovering molten metal therefrom. A cover is emplaced over the vortex well, wherein said cover has a periphery positioned in inward spaced relation to the well block to form a peripheral gas release space between said cover and the well block. The furnace also includes an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well. An inert gas and volatile hydrocarbon gas atmosphere is positioned in the charge well beneath the cover, and this atmosphere is releasable through said peripheral gas release space.
[0029] Also encompassed by the present invention is a metal-melting furnace which includes a main chamber and a circulation well connected to the main chamber by a communication passageway. There is also a vortex well, which may sit in or be the circulation well, containing a molten metal vortex and having a periphery, a top and an exit outlet for recovering molten metal therefrom and a cover is emplaced over the vortex well adjacent the surface of the molten metal vortex. The furnace also includes an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well. An inert gas atmosphere is also positioned in the vortex well beneath the cover or above the surface of molten metal.
[0030] Also encompassed by the present invention is a metal-melting furnace which includes a main chamber and a circulation well connected to the main chamber by a communication passageway. There is also a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom and a cover emplaced over the vortex well. A feed tube extends through said cover to enable metal chips to be added to the vortex well adjacent the periphery of said vortex well. The furnace also includes an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well. An inert gas atmosphere is also positioned in the vortex well beneath the cover.
[0031] Also encompassed by the present invention is a metal-melting furnace which includes a main chamber and a circulation well connected to the main chamber by a communication passageway. The furnace also includes a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom and said vortex well is positioned in a vortex well block. A cover is also emplaced over the vortex well. There is also an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port tangentially arranged with respect to the periphery of said vortex well at or near the top of the vortex well. An inert gas atmosphere is positioned in the vortex well beneath the cover. An end block is also positioned in adjoining relation to the vortex well block. These blocks are connected by a projection extruding from one block which engages a recess in the other block. The circulation well is contained in said adjoining blocks.
[0032] Also encompassed by the present invention is a metal-melting furnace which includes a main chamber and a circulation well connected to the main chamber by a communication passageway. There is also a vortex well having a periphery, a top and an exit outlet for recovering molten metal therefrom and may include a cover emplaced over the vortex well. A feed tube extends through said cover to enable metal chips to be added to the vortex well. The vortex well is adapted to hold molten metal up to a maximum level from the bottom of the vortex well. The furnace also includes an inert gas bubble actuated molten metal pump having an entry port in the circulation well and an exit port to the vortex well. The exit port is positioned so that it is adapted to lie at least partially above the maximum level of molten metal held in the vortex well. Preferably, the exit port lies at least 50% or entirely above the maximum level of molten metal in the vortex well. An inert gas atmosphere is also positioned in the vortex well beneath the cover or containment means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The present invention is further described by means of the accompanying drawing in which:
[0034] [0034]FIG. 1 is a vertical cross-sectional view of a molten metal pump and furnace for use therewith which comprises a first preferred embodiment of the present invention;
[0035] [0035]FIG. 2 is a cut away perspective view of the main molten metal chamber, circulation wall, vortex well and adjacent chamber of the molten metal pump and furnace in FIG. 1;
[0036] [0036]FIG. 3 is a cross-sectional through 3 - 3 in FIG. 2;
[0037] [0037]FIG. 4 is a partial end view of the molten metal pump and furnace shown in FIG. 1 from 4 - 4 ;
[0038] [0038]FIG. 5 is a cross-sectional view through 5 - 5 in FIG. 1;
[0039] [0039]FIG. 6 is an end view from 6 - 6 of the molten metal pump and furnace shown in FIG. 1;
[0040] [0040]FIG. 7 is a detailed view of area 7 in FIG. 1;
[0041] [0041]FIG. 8 is a cross sectional view through 8 - 8 in FIG. 7;
[0042] [0042]FIG. 9 is a partial top view of the well block and end block from 9 - 9 in FIG. 7;
[0043] [0043]FIG. 10 is a vertical cross-sectional view similar to FIG. 1 in which the feed tube and vortex well cover are in their elevated positions;
[0044] [0044]FIG. 11 is a detailed view similar to FIG. 7 in which the feed tube and vortex well cover are in intermediate elevated position still covering the vortex well;
[0045] [0045]FIG. 12 is a top plan view of the vortex well lock and part of the end block from 12 - 12 in FIG. 11 in which an alternate vortex well cover is shown;
[0046] [0046]FIG. 13 is a detailed cross-sectional view of a second embodiment of a molten metal pump and furnace for use therewith in accordance with the present invention, in which the outlet of the molten metal pump is positioned at least partially above the uppermost level of molten metal in the vortex well; and
[0047] [0047]FIG. 14 is a detailed cross-sectional view of a third embodiment of a molten metal pump and furnace for use therewith in accordance with the present invention, in which the outlet of the molten metal pump is positioned totally above the level of molten metal in the vortex well.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0048] Referring to FIGS. 1 - 9 , the furnace is shown generally at 10 has a bottom wall 12 , side walls 14 and 16 , front wall 18 and a rear wall 19 . Furnace 10 also has an intermediate transverse wall 20 which defines along with the other wall a main chamber 22 . Conventional fossil fuel burners (not shown) are used to maintain a molten metal bath 24 in this main chamber. Main chamber 22 also has a cover, shown in fragment, at numeral 26 . Adjacent main chamber 22 is a circulation chamber 28 also having a molten metal bath 30 which is connected to main chamber 22 by means of communicating passageway 32 . The molten metal may be aluminum, magnesium, zinc, copper, brass or steel. Adjacent the circulation chamber 28 there is a molten metal pump shown generally at 34 which includes an end block 36 . Adjacent end block 36 there is well block 38 . Preferably well block 38 is a separate and replaceable block of refractory material. It would alternately be possible to integrate end block 36 and well block 38 into a single unit. In the end block 36 there is end block projection 40 which engages recess 42 on well block 38 . Between end block 36 and well block 38 there is also a vertical space 44 . As may be seen in FIG. 7, in end block 36 there is a vertical passageway 46 which has a lower opening 48 and a medial outlet 50 . An inert gas line 52 extends from a tank 54 containing nitrogen, argon or other inert gas, to controls 56 and then to inert gas outlet 58 into passageway 46 . Adjacent medial outlet 50 of vertical passageway 46 there is a seal 60 at the point vertical passageway 46 connects to horizontal passageway 64 in well block 38 . Horizontal passageway 64 has an opening 66 and an outlet 68 and may be adjacent a plate 70 with a plurality of apertures as at aperture 72 . As is conventional in molten metal pumps, such as in molten metal pump 34 , there are a plurality of inert gas bubbles 74 , 76 , and 78 in vertical passageway 46 and horizontal passageway 64 . Bubbles 74 , 76 and 78 rise through passageways 46 , 64 to move molten metal masses as at 80 and 82 from circulation chamber 28 to vortex well (shown generally at 84 ). Above plate 70 there is an inert gas collection recess 86 in well block 38 . Vortex well 84 has an upper region 88 , medial region 90 and a lower region 92 with a surrounding liner 94 . At the bottom of the lower region 92 there is a lower outlet 96 which communicates with a bottom recess 98 in well block 38 . A horizontal passageway 100 extends through to an intermediate well 102 . In this intermediate well 102 there is another molten metal bath 104 which re-circulates back to main chamber 22 by means of communicating passageway 106 . Above vortex well 84 there is a refractory cover 108 . Other suitable vortex well containment means such as an upward extension of the vortex well shown generally as numeral 109 in FIG. 7 may be substituted for cover 108 . Cover 108 will be equipped with a sensor 110 which overlies a molten metal vortex 112 in vortex well 84 . Sensor 110 senses the surface level 400 of molten metal vortex 112 to prevent overfilling of furnace 10 . Between cover 108 and molten metal vortex 112 there is an inert gas atmosphere or blanket 114 which is continuously or intermittently replenished with inert gas from inert gas bubbles in molten metal pump 34 . These bubbles enter recess 86 through apertures, as at aperture 72 , in plate 70 . Between cover 108 and well block 38 there is a peripheral space 116 which allows for the formation of a combustion zone 118 for allowing oils, paints, lacquers as well as other volatile hydrocarbons to exit from below cover 108 and be burned off. It will be appreciated that this peripheral space 116 will also allow the escape of inert gas from the inert gas atmosphere or blanket 114 as additional inert gases are added to this space. Well cover 108 will have sufficient space around its periphery to allow oil, paints, lacquer or nitrogen, as well as any other volatile hydrocarbons which have been carried into the molten metal stream or the scrap charge material, to exit from below cover 108 . Heat resistant cover 108 may be adjustable in height, but normally provides several inches of clearance above surface level 400 of molten metal bath for the containment of the replenishing supply of inert gas. As seen in FIG. 1, above combustion zone 118 there is a smoke collection hood 120 with air intakes 124 and 126 having respective closure doors 128 and 130 . From smoke collection hood 120 there is a line 132 to a stack or particle collection equipment (not shown). Extending downwardly through smoke collection hood 120 there is a scrap feed tube 134 in which scrap as in metal chips 136 are fed into molten metal vortex 112 in vortex well 84 . It will be appreciated that metal scrap may be substituted for metal chips and, for the purposes of this disclosure, the term “metal chips” should be understood to include both metal chips and metal scrap. Metal chips 136 are preferably fed tangentially into molten metal vortex 112 adjacent the periphery of vortex well 84 . Feed tube 134 is attached to cover 108 by means of a flange 138 . At its upper end, feed tube 134 receives metal chips from a hopper 140 which is in turn fed by a screw conveyor 142 which receives metal chips 136 from a feed opening 144 .
[0049] Referring to FIG. 10, it will be seen that feed tube 134 and cover 108 may be withdrawn upwardly from vortex well 84 by well known conventional means.
[0050] Referring to FIG. 11, it will be seen that feed tube 134 may also be adjusted in height so that cover 108 lies proximate the top of vortex well 84 . The height of inert gas blanket 114 is thereby adjusted.
[0051] Referring to FIG. 12, an alternate embodiment of the cover is shown. In this embodiment a well block 146 is shown as well as a fragmented portion of end block 148 . A vertical space 150 is interposed between the well block 146 and end block 148 . An alternate cover 152 is positioned on the top of the well block 146 by means of radial peripheral supports 154 , 156 , 158 and 160 . Between cover 152 and well block 148 there are peripheral spaces 162 , 164 , 166 and 168 and positioned above these peripheral spaces there are respectively combustion zones 170 , 172 , 174 and 176 . A feed tube 180 , that is connected to cover 152 by means of a bracket 182 , allows metal chips to be fed into molten metal vortex 184 .
[0052] Referring to FIG. 13, there is a shown a second embodiment of a molten metal pump and furnace in accordance with the present invention. The basic structure and function of the furnace is the same as previously described. However, the structure of the molten metal pump is different in that the outlet of the pump into the vortex well is at least partially elevated above the molten metal in vortex 112 . A molten metal pump, generally shown at 234 lies adjacent the circulation chamber 28 . Molten metal pump 234 includes an end block 236 and a well block 238 . Preferably well block 238 is a separate and replaceable block of refractory material. It would alternately be possible to integrate end block 236 and well block 238 into a single unit. In end block 236 there is end block projection 240 which engages recess 242 on well block 238 . End block 236 has a vertical passageway 246 which has a lower opening 248 and a medial outlet 250 . An inert gas line 252 extends from a tank (not shown)containing nitrogen, argon or other inert gas in the same manner as previously described. Gas line 52 terminates in outlet 58 into passageway 246 . Adjacent medial outlet 250 of vertical passageway 246 there is a seal 260 at the point vertical passageway 246 connects to horizontal passageway 264 in well block 238 . Horizontal passageway 264 has an opening 266 and an outlet 268 . Vortex well 84 is adapted to hold molten metal therein. When the maximum amount of molten metal is held within vortex well 84 , the molten metal will rise to a maximum specific level signified by a distance D from the bottom wall 12 of the furnace 10 . As will be understood by those skilled in the art, different size furnaces will be adapted to hold different maximum amounts of molten metal in the vortex well of that particular size furnace. Those different maximum amounts of molten metal will each rise to a different specific level for each size of furnace.
[0053] In accordance with one of the main features of the present invention, passageway 264 enters vortex well 84 at a point where at least part of the outlet 268 lies above the level D for that size furnace, i.e. at least partially above the level of the maximum amount of molten metal that may be held in the vortex well 84 . Preferably outlet 268 enters vortex well 84 at a point where at least 50% of outlet 268 lies above level D, i.e. at least 50% of the outlet 268 will be elevated above the level of the maximum amount of molten metal that may be held in the vortex well 84 . Horizontal passageway 264 has a longitudinal centerline and preferably that centerline lies at least 50% above level D.
[0054] As is conventional in molten metal pumps, such as in molten metal pump 234 , there are a plurality of inert gas bubbles 274 , 276 , and 278 in vertical passageway 246 and horizontal passageway 264 . Bubbles 274 , 276 and 278 rise through passageways 246 , 264 to move molten metal masses as at 279 , 280 and 282 from circulation chamber 28 to the vortex well 84 . By assuring that the outlet 268 is positioned at least partially and preferably at least 50% above the maximum level D of the molten metal in vortex well 84 , the back-pressure exerted by molten metal in the vortex well 84 on the material in horizontal passageway 264 and vertical passageway 246 is substantially reduced. The reduction in back-pressure allows the bubbles 274 , 276 and 278 and therefore the metal masses 279 , 280 and 282 to move more easily through passageways 246 and 264 . This increases the efficiency of the molten metal pump 234 . As molten metal mass 279 is forced through horizontal passageway 264 and begins to flow into vortex 112 , a gap 281 forms between the interior of passageway 264 and the upper surface 283 of molten metal mass 279 . The inert gas bubble 274 moving through passageway 264 is released into gap 281 as molten metal mass 279 flows into vortex 112 and the gas becomes part of blanket 114 .
[0055] It should also be noted that in the second embodiment of the present invention, the gas bubbles 274 , 276 and 278 moving through said molten metal pump are directly released into the blanket 114 lying between the surface 209 of the molten metal in vortex 112 and the cover 108 .
[0056] A third embodiment of the invention is shown in FIG. 14. As with the second embodiment of the invention, the furnace's structure and function are the same as previously described. However, a third embodiment of the molten metal pump, generally referred to as 334 , is provided. The basic structure of molten metal pump 334 is the same as in the second embodiment of the invention, except that the outlet 368 of the horizontal passageway 364 lies entirely above the level of the maximum amount of molten metal that may be held in the vortex well 84 . The maximum level that the molten metal may rise to in vortex well 84 is signified by the distance E from the bottom wall 12 of furnace 10 . As previously set out, it will be understood that different size furnaces will hold different amounts of molten metal and therefore level E will be different for different size furnaces. The bottom 368 a of outlet 368 preferably is elevated a spaced distance F above the maximum level E of molten metal in vortex well 84 . A gas bubble 374 moving through vertical passageway 346 pushes a metal mass 379 before it. As metal mass 379 begins to drop out of outlet 368 and into vortex 112 , a gap 381 is formed between the interior of horizontal passageway 364 and the upper surface 379 a of the molten metal mass 379 . As molten metal mass 379 drops into vortex 112 , gas bubble 374 merges with the gases in gap 381 and becomes part of blanket 114 . The structure of molten metal pump 334 reduces the back-pressure that could be exerted by molten metal in the vortex 112 on the material in horizontal passageway 364 and vertical passageway 346 . The reduction of the back-pressure allows bubbles 374 , 376 and 378 and therefore the molten metal masses 379 , 380 and 382 to move more easily through horizontal passageway 364 and vertical passageway 346 . By assuring that the outlet 368 is positioned entirely above the maximum level E of the molten metal in vortex well 84 , the back-pressure exerted by molten metal in the vortex well 84 on the material in horizontal passageway 364 and vertical passageway 346 is substantially reduced or eliminated. This again improves the efficiency of the molten metal pump and the furnace.
[0057] As was the case with the second embodiment of the present invention, the gas bubbles 374 , 376 and 378 moving through said molten metal pump are directly released into the blanket 114 lying between the surface 309 of the molten metal in vortex 112 and the cover 108 .
[0058] The operation of the furnace will be described with reference to the first embodiment of the invention, but it will be understood by those skilled in the art that all three embodiments of the invention function in essentially the same manner. In the operation of the molten metal pump and furnace of the present invention, metal chips 136 are fed into feed opening 144 of conveyor 142 . Conveyor 142 transports metal chips 136 to hopper 140 from which they descend into feed tube 134 and into vortex well 84 . Chips 136 drop into molten metal vortex 112 . At the same time, nitrogen or another inert gas is drawn from tank 54 through line 52 and controls 56 . The gas forms bubbles, as at bubble 78 , in vertical passage way 46 of molten metal pump 34 . These inert gas bubbles move molten metal masses, as at mass 82 , from molten metal bath 30 in circulation chamber 28 to molten metal vortex 112 in vortex well 84 . When these bubbles, as in bubble 74 , enter horizontal passageway 64 of molten metal pump 34 , they pass through apertures, as at aperture 72 , in plate 70 to enter recess 86 . Thereafter the bubbles enter vortex well 84 between molten metal vortex 112 and cover 108 to form inert gas atmosphere or blanket 114 . Alternatively inert gas blanket 114 may be contained by the upwardly extending walls of vortex well 84 . This inert gas blanket 114 reduces the formation of oxidation on the metal chips entering molten metal vortex 112 . Oil, paints, lacquers and other volatile hydrocarbons which may be present within the metal chips are volitized and passed through peripheral space 116 (FIG. 7) between cover 108 and well block 38 to be burned in combustion zone 118 . Metal chips flow along with the rest of molten metal vortex 112 in a swirling downward path to outlet 96 , through medial region 90 , into lower region 92 , through outlet 96 and into bottom recess 98 . The direction of the molten metal is then changed to a lateral flow path through horizontal passageway 100 into intermediate well 102 . From intermediate well 102 , molten metal in molten metal bath 104 moves through passageway 106 and into main chamber 22 . After heating in main chamber 22 , molten metal passes through passageway 32 into circulation chamber 28 . From molten metal bath 30 in circulation chamber 28 , the molten metal is again pumped through molten metal pump 34 and back to vortex well 84 where additional metal chips are added under inert gas blanket 114 in the manner previously described. It will be understood that it would alternately be possible to remove molten metal from passageway 32 adjacent circulation chamber 28 to vortex well 84 . For the purposes of this disclosure, the removal of molten metal from circulation chamber 28 to vortex well 84 will be considered to also include the embodiment of removing molten metal from adjacent passageway 32 .
[0059] It will be appreciated that a molten metal pump and furnace for use therewith and a method for its operation has been described in which oxidation of metal chips entering molten metal vortex is substantially reduced.
[0060] It will also be appreciated that the present invention allows for the combination of the functions of circulating molten metal in a fossil fuel reverberatory furnace and submerging metal chips in an open sidewell chamber to cause the melted feed stock to be rapidly circulated back into the main chamber of the furnace. Any resulting loss in temperature due to the introduction of the cold scrap, can quickly be recovered in the presence of the combustion burners located in the enclosed main chamber of the furnace.
[0061] It will also be appreciated that the present invention also lends itself to melting materials such as used beverage cans (UBC) with substantially improved melt yield, without requiring the prior step of de-lacquering the UBC in advance of this melting process.
[0062] In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.
[0063] Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described. | 4y
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BACKGROUND OF THE INVENTION
The invention relates to a method for electrical discharge machining according to the wire cutting principle. This method and the apparatus used with it can in particular be employed where extremely accurate cutting contours are required at the maximum working speed.
Of late, so-called short-duration pulse generators have been used as working pulse sources in wire cutting and have led to considerable advances with regard to the working speed (e.g. described in U.S. Patent Application Ser. No. 825,036) now U.S. Pat. No. 4,163,887, Buhler et al, assigned to the assignee of this application).
Although with this type of generator vibrations on the wire electrode can be eliminated, the greatly increased working forces cause a permanent deflection of the wire electrode, which is sensitive to bending. This deflection, which is in the direction opposite to the working direction, causes significant contour errors when cutting curved contours.
A temporary, uncontrolled deflection of the wire electrode may also be brought about by other forces, caused for example by gas bubbles in the dielectric, or turbulent flows thereof, or material stresses in the actual wire electrode.
Influencing of the cutting contour by deflection of the wire electrode must be prevented.
One approach to this problem is described in Japanese Pat. No. 119,393/74, which proposes a theoretical determination of the deflection by calculation and its compensation by means of a numerical control system. However, although this method may be satisfactory for straight cutting contours, serious problems occur in the case of a curved cutting contour because it is not possible to calculate the path of the deflection from one axial direction to the other. Therefore, this method is not practical.
Another approach to this problem is disclosed in DE-OS 2,635,766, to which U.S. Pat. No. 2,635,766 corresponds, which proposes reducing the generator output and the working speed in proportion to the increased curvature of the cutting contour. However, this has the disadvantage of very considerable cutting efficiency losses in the case of frequently curved cutting contours, while the error is only partly compensated.
Still another approach is proposed in GB Pat. No. 1,512,654, to which U.S. Pat. No. 4,104,502, assigned to the assignee of this application, corresponds, where the wire electrode is subjected to the action of additional currents and additional voltages in order to provide compensation by means of electro-magnetic and electro-static forces acting on the wire electrode. Unfortunately, this leads to additional loading of the wire electrode by electric heat and arc discharges, which once again brings about cutting efficiency losses. Furthermore, the electromagnetic forces are only active with ferromagnetic workpieces.
None of these three approaches is able to obviate faults caused by gas bubbles and turbulent flows in the dielectric or caused by material stresses in the wire electrode.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic, partially sectioned side view of a wire cutting machine in accordance with a preferred embodiment of the present invention.
FIG. 2 is a diagrammatic cross-sectional view of a wire electrode of the machine of FIG. 1 in a deflected position.
FIG. 3 is a graphical representation of a curved path contour, such as that which the electrode of FIG. 2 is to follow.
FIG. 4 is a diagrammatic cross-sectional view of a wire electrode displacement pickup system of the electrolytic type for the machine of FIG. 1.
FIG. 5 is a diagrammatic cross-sectional view of a wire electrode displacement pickup system of the light sensor type for the machine of FIG. 1.
FIG. 6 is a schematic circuit diagram for a sensing system of the type of FIG. 4.
FIG. 7 is a schematic circuit diagram for a sensing system of the type of FIG. 5.
FIG. 8 is a schematic circuit diagram for an analog computer for processing into analog voltage signals the signals from the sensing systems of the circuits of FIGS. 6 and 7.
FIG. 9 is an operational diagram for the analog computer having the circuit of FIG. 8.
FIG. 10 is a functional schematic diagram of the operation of a wire electrode path correction system of the machine of FIG. 1 which corrects via the main drive positioning drive of the machine.
FIG. 11 is a functional schematic diagram of the operation of a wire electrode path correction system of the machine of FIG. 1 which corrects via an auxiliary axial drive.
It is an object of the present invention to obviate the above-described contour errors and thereby significantly increase the precision of the wire cutting method without having to accept losses in the working speed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
According to the present invention, with reference to FIG. 1 of the drawings, the deflection of the wire electrode 1 with respect to the rest position is measured by at least one displacement pickup system 7 located between a wire guide 5 and the workpiece 6 around the wire electrode 1. With the aid of the deflection information ΔX, ΔY, as shown in FIG. 2, the feed path is constantly corrected in such a way that wire electrode 1 is always positioned on the prescribed path.
The correction of the feed path is achieved in such a way that a control instruction X-ΔX, Y-ΔY formed from the desired position X and Y and the deflection ΔX, ΔY subtracted therefrom is supplied to the X, Y main axial drive 25, 26, as shown in FIG. 10. The term "axial" in this regard means along X or Y cartesian coordinate axes.
The correction of the feed path is also achieved in such a way that via a control amplifier 28, as shown in FIG. 11, and an X-Y auxiliary axial drive 29, 30 the wire guide 5 is corrected relative to guide arm 2 (FIG. 1) until the displacement pickup, which is fixed to the guide arm 2, no longer detects a deflection error ΔX, ΔY.
The method for the currentless positioning and alignment of the wire electrode 1 is utilized in that the electrode 1 is moved towards an electrically conductive or non-conductive reference surface until the displacement pickup system 7 indicates a deflection error ΔX, ΔY and is subsequently moved in the opposite direction until the deflection error ΔX, ΔY again assumes a zero value.
The displacement pickup system 7 for obtaining deflection information ΔX, ΔY, as shown in FIG. 4, comprises four test electrodes 9 arranged in crosswise manner about wire electrode 1 in the X, Y main axial direction, while the dielectric 8 supplied to the working zone constantly flows around the arrangement. An a.c. voltage source is applied between wire electrode 1 and each of the test electrodes 9 and the alternating currents flowing between the wire electrode 1 via dielectric 8 and test electrodes 9 are rectified and measured by means of absolute value formers 14 of FIG. 6.
Another type of displacement pickup system 7 is shown in FIG. 5. It comprises in each one light source 10 and a double light sensor 11 located in respective x and y directions, as shown in FIG. 5, arranged around wire electrode 1 in such a way that in the case of a non-deflected electrode 1, an equally wide shadow zone is formed on both sensor halves 11a, 11b of the double light sensors 11, and in the case of a deflected electrode 1 the shadow zone is enlarged to the same extent on one sensor half 11a as it is reduced on the other sensor half 11b. The consequently changed output signals of double light sensors 11 are measured and amplified by means of amplifiers 16.
The output signals |X+|, |X-|, |Y+|, |Y-| of the displacement pickup system 7 are in each case further processed by an analog computer 21 (FIGS. 8, 10, 11), each of which comprises (FIG. 8) a summator 18, an inverter 19 with amplification 0.5, a differentiator 17, and a division circuit 20. The average value of the positive and negative components of each axial direction X, Y is calculated by means of summator 18 and inverter 19 and in differentiator 17. The average value is subtracted from the positive component and, finally, the value is divided by the average value in the division circuit 20.
For the further processing of the output signals ΔX, ΔY of the analog computers 21, the signals are quantized by means of analog-digital converters 22 (FIG. 10).
The quantized output signals of the analog-digital converter 22 are fed to the address inputs of the read-only memory 23. Each storage location of read-only memory 23 contains an optionally corrected value for the deflection of the wire electrode 1, and consequently compensates a non-linearity of the displacement pickup system 7.
The analog computers 21 and control amplifiers 28 (FIG. 11) for each axial direction X, Y are connected behind the displacement pickup system 7. The control amplifiers 28 control the auxiliary axial drives 29, 30 in such a way that wire guide 5, and consequently wire electrode 1, are so displaced relative to the displacement pickup system 7 that deflection errors ΔX, ΔY seek to reach the zero value.
The advantages obtainable with the invention are that each deflection or displacement of the wire electrode can be accurately determined without undesired feedback and a correction thereof can be automatically performed in a simple way. Even in the case of greatly curved cutting contours, there is no need to reduce the maximum possible working speed. Furthermore, the invention makes it possible for the first time to currentlessly position the wire electrode relative to reference surfaces of the workpiece or on wire alignment devices without galvanic contact. Thus, a greater positioning accuracy without damaging the workpiece or wire alignment device is achieved.
FIG. 1 shows the wire cutting arrangement according to the invention. In a generally known manner, wire electrode 1 is unwound from a first wire bobbin 3 under tensile stress, passes through the working zone in workpiece 6 and is wound onto a second wire bobbin 3. The dielectric 8, which for wire cutting is generally a treated water with a conductance of 1 to 100 μS/cm, is passed into the working zone. The working pulses supplied by the generator +G,-G are applied between workpiece 6 via contacts 4 and wire electrode 1. The function of wire guides 5 is to maintain wire electrode 1 in a clearly defined position. In general, wire bobbins 3, contacts 4, and guides 5 are mounted on a guide arm 2. This complete arrangement performs a movement relative to workpiece 6 in accordance with the desired cutting contour.
Despite the maximum possible tensile stress applied to wire electrode 1, depending on the working forces, the latter remains deflected between about 5 and 100 μm in the indicated manner. An upper and possibly a lower displacement pickup system 7 is used to determine this displacement or deflection. The lower displacement pickup system is particularly applicable when the correction of the feed path is achieved by means of a control amplifier and an auxiliary axial drive for a wire guide, the auxiliary axial drive correcting the position of the wire guide relative to the guide support structure until the displacement pickup system, which is fixed to the support structure, no longer detects a deflection error. The displacement pickup systems 7 are also fixed to guide arm 2.
FIG. 2 shows wire electrode 1 in greatly enlarged cross-sectional form. The dotted outlines indicate the rest position of wire electrode 1, while the solid-line outlines indicate its position under loading by working forces. Wire electrode 1 is displaced by amount a in some direction, and the problem therefore exists of measuring and correcting this displacement error by components ΔX, ΔY in the X and Y main axial direction.
FIG. 3 shows by means of a given curved path A-B what happens when there is a displacement a. If no correction takes place, the cut contour is formed on the significantly displaced path C-D. According to the invention, the wire guides 5 perform a corrected path E-F, which at all times differs from the measured quantity -a or its components -ΔX and -ΔY by the prescribed path. The contour cut in workpiece 6 is consequently identical with the desired path A-B.
FIG. 4 illustrates a particularly suitable measuring method for the displacement pickup system 7. This method is known for conductivity measuring cells for liquids. An alternating voltage is applied between two electrodes and conclusions are drawn regarding the conductance by means of the measured current and the mechanical dimensions of the cell.
The basic relationship is:
______________________________________ ##STR1##η : conductance in μS/cml : length of measured liquid column in cmA : cross-section of measured liquid column in cm.sup.2R : resistance in M Ω determined from the voltage and current.______________________________________
In the arrangement according to the invention, there are four measuring cells and conclusions are drawn regarding the length l and not regarding the conductance.
Wire electrode 1 serves as a common electrode for all four measuring cells and around which four test electrodes 9 are provided in crosswise manner in the main axial directions X+, X-, Y+, Y-. The treated dielectric with a conductance of 1-100 μS/cm flows through the whole arrangement. The geometry of the cells is selected in such a way that for the given range of conductance and displacements of wire electrode 1 of approximately 5 to 100 μm, resistances R approximately in the range 100Ω and 1 MΩ will be measured.
FIG. 6 illustrates a suitable measurement circuit for the arrangement of FIG. 4. An a.c. voltage source 12 of, for example, 10 V r.m.s. value and for example with a line frequency of 50 or 60 Hz is supplied by means for current supply 4 or similar means to wire electrode 1 and by means of in each case one absolute value former 14 is supplied to the four test electrodes 9. An a.c. voltage must be used in order to produce no electrolytic effects, such as corrosion and wear to wire electrode 1 and test electrodes 9. The frequencies and voltage configurations used are of secondary importance, but the symmetry of the a.c. voltage is important. The r.m.s. value of the a.c. voltage source 12 could for example be adapted to the conductivity of the dielectric, in order not to overdrive analog computer 21 according to FIG. 8. The function of absolute value formers 14 is to rectify the alternating currents flowing across the varying resistors 13 of the measuring section and transform them into voltage signals. Thus, the four output signals |Y-|, |Y+|, |X- |, |X+| only assume positive values. With regard to the absolute value former 14 reference is made to the book of McGraw-Hill publishing company Dulsseldorf/New York: Applications of Operational Amplifiers 1973 by Jerald Graeme, page 127; a schematic abbreviated circuit diagram is illustrated with respect to the X+ test electrode.
FIG. 5 shows another very suitable measuring method for the displacement pickup system 7. A lightsource 10 and a double light sensor 11 for each main axial direction X, Y are arranged around wire electrode 1 in such a way that the shadow caused by electrode 1 uniformly covers sensor halves 11a, 11b in the rest position. In the deflected position, the asymmetry of the shadow causes a corresponding asymmetry of the lighting intensity on the two sensor halves 11a, 11b and consequently a corresponding change to their output signals. The light source 10 may comprise bulbs or preferably light-emitting diodes. The double light sensor 11 can for example be a double photo diode of type STDD-210 of Sensor Technology, Chatsworth, California, USA. This component contains two photodiodes only 20 μm apart. As is known, with photodiodes by measuring the inverse current with voltage applied in the inverse direction conclusions can be drawn on the lighting intensity. This arrangement also provides the possibility of operating light sources 10 in a pulsed manner, for example with a frequency of 1 to 100 kHz and then only evaluating the alternating current component of the double light sensors. This increases the security against disturbances and interference.
FIG. 7 shows a solution of how measurement can take place according to the light sensor method. A. d.c. voltage source 15 of for example 20 V subjects the photo diodes of the double light sensors 11 to the action of an inverse current. In accordance with the lighting intensity from outputs X+, X-, Y+, Y- flow the inverse currents of the photodiodes amplified by means of amplifier 16 and converted into analog voltage signals |X+|, |X-|, |Y+|, |Y-|. In principle, these signals are of the same type as in FIG. 6 and both can be further processed in analog computer 21.
FIG. 8 illustrates the analog computer detailed for the X axis and represented as a block for the Y axis. The function of analog computer 21 is to so prepare the measured values that influences such as the conductance of dielectric 8, the diameter of wire electrode 1, the intensity of light source 10, the aging of the double light sensors, contamination, temperature and the like are eliminated. This is achieved in that the average value of the two absolute values |X+|, |X-| of each axial direction is calculated, said average value is subtracted from the absolute value in the positive axial direction |X+| and the positive or negative quantity obtained is related to the previously calculated average value. Reference can be made in this connection to a relative error ΔX which can vary from -1 to +1. Using a constant (e.g. 100 μm) determined by calibration, the actual deflection ΔX in μm can be found by multiplying with the relative error. As it is in any case possible to operate with voltage levels, e.g. -10 V to +10 V, said constant is unnecessary, it being merely necessary to ensure that the total amplification of the measuring arrangement and analog computer is adjusted in such a way that the analog-digital converter 22 in FIG. 10 supplies the digital value corresponding to the deflection or displacement.
FIG. 9 shows a graphical representation of the calculation process for the X axis. The absolute values |X+| and |X-| are obtained at the inputs and are summated in a summator 18 of FIG. 8. As this summator inverts, an inverter 19 is connected behind it which, due to its amplification A=0.5, simultaneously divides the sum by 2, which gives the arithmetic means of |X+| and |X-|. This average value is subtracted from the absolute value |X+| in a differentiator 17. (In the diagram of FIG. 9 by reversing the direction of the mean value |X+|+|X-|/2 and summating to the absolute value |X+|). This leads to the component ΔX, which can assume positive or negative values, but still has the various disturbing or interfering influences described, which are suppressed by dividing in the division circuit 20. At the output, component ΔX is obtained as a positive or negative value, which behaves proportionally to the sought component ΔX of the deflection error. Assuming that these disturbing influences act uniformly on absolute values |X+| and |X-| during division, they occur in the numerator and in the denominator and can therefore be shortend. An identical analog computer 21 is provided for the Y direction. For the explanation of the circuits used, i.e. differentiator 17, summator 18 and inverter 19, reference is made to the book "Electronics for Engineers" of the Cambridge University Press, England, 1973 pp. 120-123 and 111, while for the division circuit 20 reference is made to RCA Handbook 1975 "Linear Integrated Circuits" No. SSD-201C, pp. 449 and 450.
FIG. 10 shows the diagrammatic arrangement for the correction via the main axial drive 25, 26. The term "main axial drive" is understood to mean the feed system, which in a generally known manner performs the relative movement between wire electrode 1 and workpiece 6 predetermined by the numerical control system 27. The deflection of wire electrode 1 measured by the displacement pickup system 7 is supplied by analog computer 21 in components ΔX and ΔY of the deflection error. By means of analog-digital converter 22 this analog deflection information ΔX is for example quantized with an 8 bit resolution. Thus, for example, 256 gradations of in each case 1 μm with sign are made available. Thus, the maximum measurable deflection of wire electrode 1 is 255 μm in all directions.
A possible non-linear behaviour of displacement pickup system 7 can easily be compensated by means of the read-only memory 23 in that a correct value in the corresponding storage location is associated with each distorted digital value of output signals ΔX, ΔY of analog-digital converter 22. The correct values can be determined by calibration. The read-only memory can for example be an 8×8 bit PROM (Programmable "read-only memory").
In signal connection point 24 ΔX or ΔY is subtracted from the desired value X or Y of the deflection error and the thus modified values X-ΔX or Y-ΔY are fed to the X main axial drive 25 and the Y main axial drive 26. The signal connection point 24 is of a symbolic nature and could e.g. comprise a digital, wired-in computer logic or more probably comprises a small subprogram in a normally existing programmable computer of the numerical control system 27.
In this connection, it is pointed out with the aid of presently existing technologies such as microprocessors, multiplexers, etc. the problem of measured value preparation 21, 22, 23, 24 can be solved on a purely software basis, i.e. only by programming a computer. The four outputs |X+|, |X-|, |Y+|, |Y-| of the displacement pickup system 7 are then interrogated by an analog-digital converter 22 in the time-multiplex operation and the digital values are supplied to a programmable computer. The latter then digitally prepares the described measured values and feeds signals X-ΔX and Y-ΔY to drives X, Y, 25, 26.
FIG. 11 shows the diagrammatic arrangement for a correction by means of an auxiliary axial drive 29, 30. Apart from the known relative movements of the workpiece 6 relative to wire electrode 1 by main axial drive 25, 26 an additional small auxiliary axial drive 29, 30 is provided, which can adjust the now movably arranged wire guide 5 relative to guide arm 2 in axial directions X and Y by for example ±200 μm. The displacement pickup system 7 is fixed to guide arm 2 and measured value preparation is effected by analog computers 21 of FIG. 10. However, the analog deflection information ΔX, ΔY is supplied to the control amplifiers 28, which supply corresponding control signals to the X auxiliary axial drive 30 and the Y auxiliary axial drive 29. Thus, wire guide 5 and consequently wire electrode 1 are adjusted in such a way that the deflection error becomes smaller and the deflection information ΔX, ΔY seek to reach the value zero.
Control amplifier 28 is advantageously given a so-called PI control behaviour, i.e. its output signal is proportionally and integrally dependent on its input signal ΔX or ΔY. (Reference is made to the book "Halbleiterschaltungstechnik" U. Tietze, Springer-Verlag, New York 1971, pp. 232). As a result, a sudden change in the input signal ΔX, ΔY will result in by a corresponding sudden change at the output a very small, but very long input signal will result in maximum amplification being supplied to the output. Thus is it possible to correct the position of wire electrode 1 with optimum rapidity and accuracy. The arrangement of FIG. 10 admittedly has the minor defect that, since the displacement pickup system 7 cannot be mounted at an infinitely small distance from workpiece 6, due to the curved configuration of electrode 1, a residual error remains on workpiece 6, although the displacement pickup system 7 no longer measures a displacement. However, this can be easily compensated by a slight positive feedback to the variable gain amplifier 28, i.e. at the input of amplifier 28 deflection information ΔX or ΔY is permitted to appear in larger form to such an extent that the error becomes zero on workpiece 6. The arrangement of FIG. 11 is advantageously fitted as a component on guide arm 2 on either side of workpiece 6. | 4y
|
BACKGROUND OF THE INVENTION
(a) Field of the Invention
This invention relates to detection of Helicobacter pylori (hereinafter called H. pylori), source bacterium of gastrointestinal disorders, and in particular relates to an H. pylori detecting composition produced by applying a phenate method for ammonium ion's quantitative determination to a conventional urease enzyme test and relates to a detecting kit and method using this composition.
(b) Description of the Related Art
H. pylori is noted as a source bacterium causing gastrointestinal disorders including gastric cancer and gastroduodenal ulcers, and the WHO has prescribed H. pylori as a typed carcinogen. Precise diagnosis, i.e., accurate detection of H. pylori, should be promoted to cure gastrointestinal disorders caused by this H. pylori. H. pylori detecting methods being used up to now can be divided mainly into two types, i.e., non-invasive tests not using an endoscope and invasive tests using an endoscope to get biopsy tissue for detection purposes.
Non-invasive tests include serology tests and 13 C or 14 C Breath tests. Serology tests measuring H. pylori antibodies have a problem in that the existence of the antibody does not necessarily mean that diseases are developing because it takes more than 6 months for antibody levels to drop after the cure of diseases. The 13 C or 14 C Breath test uses the principle that if urea marked with 13 C or 14 C is ingested, it is transformed into marked CO 2 in the stomach if H. pylori exists and detected in exhaled air. However, the method is not usually used because it involves high cost equipment.
On the other hand, invasive tests are more commonly used to detect H. pylori. Invasive tests detecting methods using biopsy tissues samples collected during an endoscoping includes histology, the PCR (Polymerase Chain Reaction) method, culturing, and the urease enzyme test. Histology is a method confirming the existence of H. pylori through general tissue research, the PCR method is a method confirming the existence of H. pylori by using chain reaction of polymerization enzyme, and culturing is a method of directly cultivating H. pylori from biopsy tissue. However, there is a problem in that all these methods are difficult and take much time, so they can not be used commercially.
The urease enzyme test, which can be used easily in the endoscope chamber and is the most efficient method, uses the fact that H. pylori produces urease enzyme which has a much higher degree of activity compared to other microorganisms. That is, if urease exists urea added in the detecting kit decomposes and ammonia is produced to cause pH to be increased making a pH indicator react and change color. A H. pylori detecting method measures the activity degree of urease like this. Commercialized kits using the urease enzyme test now are “CLOtest” (U.S. Pat. No. 4,748,113), “Hpfast” (U.S. Pat. No. 5,439,801) and “Pyloritek” (U.S. Pat. Nos. 5,314,804 and 5,420,016). Compositions used in “CLOtest” include 10˜40 g/l of urea, 1˜5 g/l of bactericide, an available quantity of pK a 6.5˜8.5 indicator (phenol red) and the remainder being water, having a 5.0˜6.5 pH. However, the CLOtest has problems in that the positive rate vary with the readers because the reaction speed of urease that the above compositions and H. pylori produce is slow. Therefore, diagnosis is possible only after about 24 hours and it is not possible to obtain diagnostic results on the endoscope examination date which requires that the patient inconveniently visit the hospital once more. Furthermore, the various colors appearing after more than 24 hours makes accurate diagnosis difficult. Hpfast is fundamentally similar to the CLOtest, but different in that cell wall detergent is added and uses as an indicator mixture of phenol red, methyl red, and bromothymol blue. With Hpfast, an H. pylori positive is determined from a dark green color of pH 6.2 and a light green color of pH 6.0 is determined as an H. pylori negative. However, the accurate reading of this dark green and light green colors is difficult. Pyloritek uses a multilayer test device differently from the above mentioned CLOtest and Hpfast, the main characteristics of this is that the urease reacting part and reacted product as an ammonia detecting part are on different layers and the pHs of each layers are different. Although Pyloritek can produce diagnosis results within one hour, the false positive rate increases if the determination time exceeds one hour. Therefore, there is an increasing possibility of false positives if an accurate reaction time is not adhered to during the endoscope examination.
Moreover, the above mentioned urease enzyme methods including the CLOtest, Pyloritek, etc. could also react with the small amounts of low activity urease which bacilli such as Staphylococcus hominis, Streptococcus salivarius, E. aerofaciens, L. fermentum, etc. have and false positive rates could be increased in cases of long decision times.
SUMMARY OF THE INVENTION
The present invention is designed to solve the above mentioned problems of the conventional technology by providing a H. pylori detecting composition, a H. pylori kit, and a method for using the above composition which allows the rapid and accurate determination of whether or not a H. pylori infection exists, which is the source bacterium that causes gastrointestinal disorders. The present invention also provides the same test results after a period of time passed, and it can easily be used in the chamber of an endoscope.
In order to achieve the above described purpose of this invention, this invention first provides H. pylori detecting composition including urea from 0.5 to 4 vol %, KH 2 PO 4 from 0.05 to 0.2 vol %, phenate reagent solution from 0.8 to 1.7 vol %, an indicator from 0.002 to 0.005 vol % having a pKa of from 6.5 to 8.5 and a balance of water. Among the above described constituents, said phenate reagent solution from 0.8 to 1.7 vol % is preferably composed of manganous sulfate solution from 0.5 to 1 vol %, hypochlorite reagent from 0.2 to 0.5 vol % and phenate reagent from 0.1 to 0.2 vol % and the above described indicator is preferably phenol red. Moreover, said composition more preferably comprises gelling agent from 0.5 to 2 vol %. Especially said composition most preferably comprise 2 vol % urea, 0.05 vol % KH 2 PO 4 , 1 vol % manganous sulfate solution, 0.5 vol % hypochlorite reagent, 0.2 vol % phenate reagent, 0.0025 vol % phenol red, 1 vol % agar and a balance of water. And said composition preferably has pH from 6.0 to 7.8.
Second, this invention is made from the above described composition and provides an H. pylori detecting kit including biopsy tissue receptical test device, positive control produced by further adding 10˜20 μl of 0.1 N NaOH solution to said constituents and negative control made of said constituents wherein no biopsy tissue is placed.
Third, this invention provides an H. pylori detecting method from biopsy tissue including stages of reacting biopsy tissue with said composition and observing color change of said composition.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, serve to explain the principles of the invention:
FIG. 1 is a perspective view of detecting kit according to this invention;
FIG. 2 is a sectional view of detecting kit according to this invention; and
FIG. 3 is a drawing describing application example of detecting kit according to this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following detailed description, only the preferred embodiment of the invention has been shown and described, simply by way of illustration of the best mode contemplated by the inventors of carrying out the invention. As will be realized, the invention is capable of modification in various obvious respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not restrictive.
Hereinafter, further details of this invention are explained as follows:
In detecting H. pylori, the inventors tried to substantially lower false positive rates due to the subjectivity of the readers by transforming the existing urease enzyme tests from the methods conventionally used to a composition that uses a speedy change of colors that enables an accurate determination to be made rapidly by comparing the test results simultaneously with positive and negative controls. Namely, since test kits using existing urease enzyme tests detect the pH increase caused by OH − ions produced from the reaction of water with the ammonia generated by simply decomposing urea, the inventors tried to eliminate the ammonium ions themselves in order to increase the rate of pH change. To do this, the inventors applied the phenate method (Standard Methods for the Examination of Water and Wastewater 19th ed. 1995, American Public Health Association, pp 4-80˜4-82.) used in quantification of ammonium ions.
The Urea decomposition process by urease is presented as following reaction formula:
[reaction formula 1]
(NH 2 ) 2 CO+2H 2 O→2NH 3 +H 2 CO 3 (irreversible reaction)
(urea)
H 2 CO 3 H + +HCO 3 − (reversible reaction)
2NH 3 +2H 2 O2NH 4 + +2OH − (reversible reaction)
Total reaction: (NH 2 ) 2 CO+4H 2 O→2NH 4 30 +20H − +H + +HCO 3 −
The constituents of this present invention increase pH promptly by transforming the products of the above described urea decomposition process, i.e., ammonium ions, into indophenol blue to continue urea decomposition. In order to achieve the above described purpose, the phenate method, a remarkably effective method of measuring ammonia concentration in the aqueous solution, is applied. The phenate method, using the principle that ammonia under a manganic catalyst reacts with hypochlorite base and phenol to change into indophenol blue, can be described as the following reaction formula:
[reaction formula 2 ]
2NH 4 + +OCl − +2C 6 H 5 OH→O═C 6 H 4 ═N—C 6 H 4 —NH 2
That is, the constituents of this invention make the reaction speed faster in order to increase pH rapidly by adding phenate reagent solution to constituents used in the conventional urease enzyme test and transforming ammonium ion generated in the urea decomposition process by the above described urease into indophenol blue.
Additionally, NaOCl is among the constituents that acts to reduce false positives that follow increased concentrations due to urease from bacilli as it has an inhibiting effect on weak urease activity. This also allows test results to be obtained after longer testing time periods.
In this invention, the added quantity of phenate reagent solution is adjusted within a range so that H. pylori urease activity is not inhibited and color change of the pH indicator is not affected. This invention's constituents and the possible content range of each components is as below:
urea from 0.5 to 4 vol %,
KH 2 PO 4 from 0.05 to 0.2 vol %,
phenate reagent solution from 0.8 to 1.7 vol %,
0.002˜0.005 vol % of an indicator having pK a from 6.5 to 8.5 and a balance of water
From the above described composition, urea acts as a urease substrate which H. pylori produces, about 0.5˜4 vol % of content is an appropriate level to measure activity of urease which H. pylori produces. KH 2 PO 4 acting as a buffer solution should include 0.05˜0.2 vol %, i.e., it can not obtain desired the pH range at lower than 0.05 vol % and tends to inhibit pH change at higher than 0.2 vol %. The phenate reagent solution, acting to transform ammonium ions into indophenol blue and to inhibit urease activities of other microorganisms should be included at 0.8˜1.7 vol %, i.e, at lower than 0.8 vol % the effect of increasing the pH change speed by eliminating ammonium ions and the inhibiting effect of urease activity of other microorganisms are insufficient, while at higher than 1.7 vol % pH is increased much too high and the urease activities of other microorganisms as well as H. pylori tend to be inhibited. An indicator having a pKa from 6.5˜8.5 acts to sense pH change, with phenol red being the most appropriate in this invention, preferably between 0.002˜0.005 vol % for the precise determination. Phenol red has characteristics of showing yellow in an acid solution and a purplish-red color in a basic solution.
The above described phenate reagent solution containing in detail a manganous sulfate solution acting as a catalyst, hypochlorite reagent acting as a reactant reacted with ammonium ions and phenate reagent, and is especially desirably composed of 1 vol % manganous sulfate solution, 0.5 vol % hypochlorite reagent and 0.2 vol % phenate reagent. Moreover, it is further desirable that this constituent contains 0.5˜2 vol % of a gelling agent, e.g., agar, as it can then be used conveniently in the form of a soft gel. It is preferable that constituent is controlled in the range of pH 6.0˜7.8 because it aides precise determination when the pH is kept in this range.
Further desirable components and contents range of this invention's constituents are as follows:
2 vol % urea, 0.05 vol % KH 2 PO 4 , 1 vol % manganous sulfate solution, 0.5 vol % hypochlorite reagent, 0.2 vol % phenate reagent, 0.0025 vol % phenol red, 1 vol % agar, and a balance of water.
On the other hand, desirable components and contents of stock solution of phenate reagent solution used in this invention are as follows:
Manganous sulfate solution; 0.05 vol % MnSO 4 H 2 O, and a balance of distilled water,
Hypochlorite reagent; 1 vol % NaOCl, and a balance of distilled water,
Phenate reagent; 2.5 vol % NaOH, 8 vol % phenol, and a balance of distilled water.
This invention is to react with the above described constituents by placing biopsy tissue obtained through an endoscope on the gell made of the above described constituents and observe color change. The gell is made of he above described constituents and a positive control gell is produced by adding to the above described constituents a minimum quantity of NaOH that can show positive results, i.e., 10˜20 μl 0.1 N NaOH solution. A determination can be made as to whether or not there is an H. pylori infection comparing the color of the negative control gell in which NaOH is not added at all. Accordingly, a test device with positive and negative controls placed side by side for comparison at a glance with colors indicating positive or negative results will decrease erroneous test results due to the subjectivity of the reader.
A perspective view of a detecting kit according to this invention is presented in FIG. 1 and side view in FIG. 2, respectively. An application example of a detecting kit according to this invention is also presented in FIG. 3 . Referring to the above described FIGS. 1 to 3 , 1 is a cover, 2 is a container, most desirably a transparent container made of an acrylic material, 3 is detecting composition according to this invention, 4 is a test device, 5 is the biopsy specimen area, desirably opaquely treated such that biopsy specimen is not seen from the side, 6 is the negative control, 7 is the positive control and 8 is the biopsy sample.
A desirable practical example and comparative example of this invention are described. However, the below described practical example is only one of practical examples of this invention and this invention is not limited to the below described practical example.
[Practical Example 1]
Making H. pylori detecting compositions
First the below described composition of stock solution was prepared;
20 vol % urea, 2 vol % KH 2 PO 4 , 0.01 vol % phenol red, and 2 vol % agar.
As stock solution of phenate reagent, 100 ml of manganous sulfate solution was made by adding distilled water to MnSO 4 H2O 50 mg, 100 ml of hypochlorite reagent was made by adding distilled water to 10 ml of 10% NaOCl and the pH was adjusted to 6.8 with concentrated hypochloric acid. 100 ml of phenate reagent was prepared by adding distilled water to 2.5 g of NaOH and 8 ml of phenol. After the above described agar solution was autoclaved (121° C., 1.5 atm) for 15 minutes, it was left alone until it is used in the water tank at 55° C. and the below described 2 X reagent were produced.
A 50 ml mixture was made by mixing the above described 10 ml urea stock solution, 2.5 ml KH 2 PO 4 stock solution, 25 ml phenol red stock solution, 1 ml manganous sulfate solution, 0.5 ml hypochlorite reagent and 0.2 ml phenate reagent and adding distilled water. After bacilli of the above described produced 2 X reagent were filtered out by 0.2 μm filters, the same amount as 2% agar solution was mixed. As a result of that, the final concentration of the constituents was as below and the final pH was 7.5 at this time:
2% urea, 0.05% KH 2 PO 4 , 0.0005% manganous sulfate, 0.005% NaOCl, 0.2% phenate reagent (0.005% NaOH, 0.016% phenol), 0.0025% phenol red and 1% agar.
[Practical Example 2]
Manufacture of a H. pylori detecting kit
The composition manufactured from example 1 was injected into one wall of a multiwall plate, test device with biopsy tissue obtained from an endoscope, a positive control was made by injecting into another wall the composition manufactured and by further adding 10 μl of 0.1 N NaOH to the above described composition, a negative control was made by injecting the above described composition into another wall, thereby making an H. pylori detecting kit. The above described detecting kit is called “PET (Pylori Easy Test) kit”.
[Test Example 1]
After a patient's biopsy tissue was obtained, a CLOtest and PET of example 2 were used on that biopsy tissue simultaneouly, and the positive rate per hour was compared and the results were described in the below Table 1.
TABLE 1
Positive rate per hour
Hour
PET
CLOtest
1
10
3
2
10 (+0)
3 (+0)
3
13 (+3)
8 (+5)
4
13 (+0)
8 (+0)
12
No test
No test
24
13 (+0)
10 (+2)
Total positive rate
13/26
10/26 or 17/26*
*7 readings were difficult to determine.
As a result, PET could confirm 76.9% of total positives within one hour and 100% after 3 hours. On the other hand, CLOtest could confirm only 17.6˜30% of the positives and 100% only after 24 hours. However, uncertain color which could not be distinguished distinctly appeared after 24 hours and the positive rate was varied from 38.4% (10/26) to 65.3% (17/26) depending on the observers. Therefore, we can see that rapid dtermination is possible in the case where PET is used according to this invention.
After that, we observed the degree of consistency of PET results with the PCR method. Here, the PCR method used an amplifying method of 26 kDa protein gene, a method known as the most unique and sensitive in H. pylori detection (Ho, S, et al. 1991, Direct Polymerase Chain Reaction Test for detection of H. pylori in Human and Animals, J. Clin. Microbiol, 29 pp 2543˜2549). The results were described the following table 2:
TABLE 2
Consistency ratio with PCR method
PET
CLOtest
26/26 (100%)
16/26 (61.5%): two false negatives,
five false positives
21/26 (80.7%): when unreadable
colors were judged to be negatives
From the above described table 2, we can see that all of the 26 biopsy tissues are consistent with the results of the PCR method when using this PET invention and that the consistency ratio ranges between 61.5˜80.7% for the Clotest. Therefore, we can see that it is possible to judge that this PET invention is more precise than Clotest.
[Test Example 2]
Biopsy tissue obtained during an endoscoping was refrigerated at −20° C. for 1 week, and the PET and CLOtest were then performed according to the same method as in test example 1 with the results compared and presented in table 3 and table 4.
TABLE 3
Positive rate per hour
Hour
Practical example 1
CLOtest
1
6
1
2
11 (+5)
2 (+1)
3
13 (+2)
4 (+2)
4
13 (+0)
8 (+4)
12
13 (+0)
12 (+0)
24
13 (+0)
12 (+0)
Total positive rate
13/22
12/22*
*6 readings were difficult to determine.
TABLE 4
Consistency with PCR
PET
CLOtest
22/22 (100%)
21/22 (95.5%); one false negative
18/22 (81.8%); when unreadable colors
were judged to be negatives
From table 3 and table 4, if PET according to this invention is used, it is notable that precise judgement is possible on biopsy tissue in which urease activity of H. pylori was decreased to certain degree. {p This invention could provide H. pylori detecting compositions which tell promptly and precisely whether or not an H. pylori infection (the source bacterium causing gastrointestinal disorders) exists, and the same results can be obtained even after time has elapsed and the compositions are easily used in an endoscope chamber. The invention provides an H. pylori detecting kit and a method of using H. pylori detecting compositions.
[Test Example 3]
Urease decomposition capacity was examined on H. pylori bacterium and Staphlococcus hominis bacterium separated from biopsy tissue obtained during an endoscoping in order to examine the H. pylori peculiarity of PET.
The examination method involved first having H. pylori bacterium and S. hominis bacterium cultivated and diluted in sterilized distilled water so as to have an appropriate number of bacilli, and then PET and CLOtest were performed and compared according to the same method as in test example 1. The results were described in table 5.
TABLE 5
Peculiarity comparison on H. pylori bacterium and S. hominis bacterium
Classification
UBPH (0.02%)
CLOtest
H. pylori
10 5 cells
<30 min
within 30 min
10 4 cells
1 h
2 h
10 3 cells
No response even after
No response even after
24 hours
24 hours
S. hominis
10 7 cells
8 h
6 h
10 6 cells
No response even after
10 h
24 hours
From the above described table 5 it is noted that if PET according to this invention is used, high peculiarity detection is possible with urease activity of H. pylori showing a fast response and urease activity of other bacilli showing low response.
Although preferred embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that many variations and/or modifications of the basic inventive concepts herein taught which may appear to those skilled in the pesent art will still fall within the spirit and scope of the present invention, as defined in the following claims. | 4y
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TECHNICAL FIELD
This invention relates to a method and apparatus for igniting a High Intensity Discharge (HID) lamp. The invention has particular application in high volume commercial HID devices, where cost is an important consideration.
BACKGROUND OF THE INVENTION
HID lamps typically use a gas sealed within a glass container which conducts electricity and emits light at a particular wavelength. The wavelength is a function of the type of gas used.
In order to start, or ignite, an HID lamp, there are generally four phases the ballast must account for. The first phase is the breakover phase, in which a relatively high voltage pulse (e.g., 3 kilovolts) is applied between two electrodes of the HID lamp in order to free electrons from the gas molecules and start the conduction process. Typically the ballast must supply the high voltage pulse for a duration of approximately 10 microseconds. After the 10 microsecond 3 kilovolt pulse, a takeover state is entered. Depending on the lamp and ballast conditions, the takeover state can last on the order of hundreds of microseconds, during which the ballast must be capable of supplying approximately 280 to 300 volts to the lamp. This continues the process of bringing the gas towards a steady state of conduction.
After takeover, the HID lamp enters the run up phase. At the beginning of the run up phase, the temperature, internal pressure, and voltage within the lamp are relatively low. During the run up phase, the voltage ramps up from approximately 20 volts to approximately 90 volts over the course of a minute or even more. After that minute, the lamp enters its fourth and final stage, which is the steady state operating phase. During steady state, the lamp emits light at its normal temperature and pressure for which it was designed.
During steady state, the lamp is operating based upon a current signal which must oscillate. More specifically, because of the physics of such devices, they cannot operate on DC but must instead be operated based upon preferably a low frequency square wave signal which oscillates between a positive and negative current. Thus, the steady state may be, for example, a square wave current at 100 Hz that results in a lamp voltage which oscillates between plus and minus 90 volts.
The above four phases require that the circuitry to drive the lamp deliver a prescribed signal. More specifically, the drive circuitry must deliver the breakover ignition pulse of approximately 10 microseconds, followed by the takeover voltage of approximately 280 to 300 volts for on the order of hundreds of microseconds, and then the run up and steady state voltages. FIG. 1 is an exemplary prior art arrangement for delivering the above-prescribed signal. At ignition, a signal of approximately 400 volts is placed across capacitor 150 . The 400 volts is conveyed through device 130 and inductor 134 , and causes a signal of approximately 300 volts to appear across capacitor 132 .
Capacitor 132 causes igniter 105 to generate a pulse of approximately 3 kilovolts for approximately 10 microseconds, after which the igniter 105 appears essentially as a short circuit. The igniter is typically triggered by the voltage across capacitor 132 to generate the 3 kilovolt pulse. After the initial pulse, and when the igniter acts as an effective short circuit, the voltage of approximately 280 to 300 volts from capacitor 132 is delivered from capacitor 132 through igniter 105 to the HID lamp 108 . These 280-300 volts are maintained for on the order of hundreds of microseconds, until the takeover phase is complete. Immediately after the takeover phase, controller 110 begins the run up and steady state process. During steady state, controller 110 controls the gate voltages of 136 through 139 such that the oscillating square wave described above is delivered to the lamp 108 .
A problem with the arrangement of FIG. 1 is that the cost is relatively expensive due to the number of components. More specifically, because it is required to generate a square wave which varies its polarity periodically, four transistors are required within commutator 120 . The four transistors act in conjunction with the control voltages applied to their gates by controller 110 in order to generate the required square wave.
FIG. 2 shows an alternative prior art embodiment for delivering the prescribed four phases of signal to an HID lamp. The arrangement of FIG. 2 utilizes two capacitors 220 and 222 in series as a voltage divider. HID lamp 108 is connected between igniter 105 and point 208 . The system need not use four different transistors to create the square wave utilized during steady state. Instead, only two transistors 224 and 226 are needed. During steady state, lamp electrode 210 is connected to point 208 , and transistors 224 and 226 can be operated at high frequency and at varying duty ratios. Thus, by operating controller 218 in a fashion such that transistors 224 and 226 are alternatively switched on and off with the proper durations, the required steady state current and voltage waveforms can be delivered. Since one of the HID lamp electrodes is connected to the middle of the divider formed by capacitors 220 and 222 , only two transistors 224 and 226 are needed to generate a square wave with changing polarity.
The problem with the arrangement of FIG. 2 occurs during ignition. More specifically, in order to supply the approximately 280 volts needed to be present across the lamp 108 during takeover phase, 560 volts must be present between points 214 and 216 . This increased voltage, which is used only during the initial ignition process, creates relatively high stress on the circuit components. This either causes failures or, in the case of quality components that can withstand the stress, drives up the cost to nearly the point of using the four devices in FIG. 1 .
In view of the above, there exists a need in the art for an ignition circuit for an HID lamp which can utilize only a small number of switching devices but yet can operate without the relatively high voltages required in arrangements such as that in FIG. 2 .
SUMMARY OF THE INVENTION
The above and other problems of the prior art are overcome in accordance with the teachings of the present invention which relates to an ignition circuit for HID lamps. A two-transistor circuit is utilized which is sufficient to provide the steady state square wave voltage of approximately 90 volts. During the ignition process, a switch is utilized to switch one of two capacitors forming a voltage divider out of the ignition circuit. This results in the entire input voltage being applied to one capacitor, thereby delivering a sufficient voltage for ignition. After the ignition period, the second capacitor is switched back into the circuit, thereby forming a voltage divider and permitting the pulsed steady state voltage to be delivered to the lamp.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts an exemplary prior art arrangement for use in igniting an HID device;
FIG. 2 depicts an alternative prior art arrangement for use in igniting an HID device; and
FIG. 3 depicts an exemplary embodiment of the present invention for use in the ignition of an HID device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The arrangement of FIG. 3 includes two transistors 354 and 356 , supply capacitors 350 and 352 , capacitor 360 , and control circuitry 310 . As is conventional, an igniter 312 is connected to the HID lamp 314 .
Although not shown for purposes of simplicity, the gates of transistors 354 and 356 are connected to controller 310 , so that controller 310 may switch devices 354 and 356 on and off at the appropriate times as described hereafter. A switch 320 is placed across capacitor 352 . The switch may be implemented in the form of a solid-state device such as a MOSFET or any other conveniently available switch. The switch may also be connected to controller 310 in order to facilitate control thereof. A resistor 322 is connected in series with the switch 320 . Typical values of capacitors 350 and 352 range from 22 to 68 microfarads.
In operation, an initial bus voltage of approximately 400 volts is applied across terminals 318 and 316 , and the switch 320 is kept closed by controller 310 . This causes point 328 to be connected to terminal 316 , and thereby places approximately the entire 400 volts across capacitor 350 . Transistors 354 and 356 are operated at high frequency and at the proper duty ratios such that 280 to 300 volts are delivered across capacitor 360 , triggering the igniter 312 .
After the breakover and takeover periods, the system enters the run up phase and it is necessary to prepare the system for AC operation. Controller 310 monitors the status of the system, and after the lamp has entered the run up phase, places switch 320 into the open position. This may be accomplished for example, by removing an appropriate gate voltage from a MOSFET or similar device.
By opening such a switch, the 400 volts across terminals 316 and 318 is now divided between capacitors 350 and 352 . The circuit thus is in the arrangement shown in FIG. 2 for delivering steady state square wave current and voltage to the lamp 314 for operation. Thus, by utilizing two capacitors in series and switching one of the them out of the circuit for the breakover and takeover periods, the benefits of a reduced number of components are achieved without the expense of having to use high stress components to withstand increased voltages between terminals 316 and 318 .
The transition from the ignition phase to steady state phase must be timed correctly. More specifically, we refer to the steady state phase as AC operation, since the signal driving the HID lamp is alternating polarity square wave. It is important that the controller sense the end of takeover and immediately open switch 320 in order to place capacitor 352 back into the circuit. There are several manners in which this can be accomplished. One is to have the controller monitor the impedance measured across the HID lamp 314 . A drop in impedance occurs at the end of takeover, since the gas becomes more conductive.
Another technique is for the controller to measure the current being delivered to the HID lamp, since the end of takeover phase is marked by a sudden increase in the current being delivered to the lamp due to the lower impedance of the lamp.
Regardless of how the end of takeover is sensed, the controller 310 opens switch 320 upon sensing the end of takeover, and capacitor 352 then begins to charge naturally as capacitor 350 discharges. The total voltage between points 318 and 316 nonetheless remains substantially constant. When the voltage across each of capacitors 350 and 352 reaches approximately 200 volts, the controller 310 begins switching transistors 354 and 356 on and off appropriately to generate the steady state AC pulse signal required to drive the HID device.
By selecting capacitors 350 and 352 to have typical values on the order of 47 microfarads, the period of time it takes to charge 352 can be kept to under 100 milliseconds. This timing is important since by keeping the charge time small, the HID lamp 314 is not operating in a DC mode for an extended length of time, which could cause damage to the lamp.
If the lamp were to extinguish during operation while the power is still applied, then capacitor 352 should be discharged before re-ignition. The controller 310 will sense the extinguishing of the lamp and discharge capacitor 352 through switch 320 prior to the ignition. This discharge should be limited by the controller 310 in order to avoid massive currents destroying switch 320 .
Such a discharge is accomplished by controller 310 switching an additional resistor 322 into the path between capacitor 352 and ground in order to limit the current in the capacitor discharge path. Alternatively, the controller can properly drive switch 320 in order to limit the current permitted therethrough by regulating the gate voltage in a conventional fashion to provide for the correct current in accordance with the device characteristics. Once capacitor 352 is discharged, controller 310 may then initiate the ignition sequence again by closing switch 320 and thus place the appropriate voltage across capacitor 350 .
While the above describes the preferred embodiment of the invention, it is understood by those of skill in the art that various modifications and variations may be utilized. For example, separate power supplies may be utilized during the ignition phase and later during the steady state phase. The switch 320 may be implemented using a variety of switching devices. Such modifications are intended to be covered by the following claims. | 4y
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FIELD OF THE INVENTION
[0001] The present invention relates to electronic storage and sharing of files and other web resources, and more particularly to a method and system for specifying, assigning, and maintaining user defined metadata in a network-based photosharing system.
BACKGROUND OF THE INVENTION
[0002] Metadata has been associated with digital images, and is typically supported by online photosharing sites. However, digital image metadata has shared the same restrictions as metadata in general. It has been limited to standard metadata as defined by the various versions of the Exif standard. This metadata is of limited use to most users of digital images. Some cameras produce proprietary metadata, however, specialized PC software is required to parse, interpret, and store the image metadata. Some photo hosting sites support the specification of a limited amount of metadata. This metadata is restricted in that users cannot define new metadata fields or are limited to a fixed number of “user defined” fields. The ability to provide optional “user defined” metadata may be provided, but is limited because metadata support usually does not extend much beyond that defined by the Exif image file format standard. In addition, the methods the photoshosting sites use to store and transmit the metadata is propriety, making its use beyond that of the photohosting site limited. Further, searches are usually limited to only a subset of the limited metadata that is supported by a site.
[0003] It is expected that camera manufacturers and photohosting sites will soon begin storing the metadata they support in XML or RDF (Resource Description Framework) format. This will go along way towards making this metadata useful to a large range of applications. RDF, developed by the World-Wide Web Consortium (W3C), provides a schema language for defining metadata vocabularies that allows interoperability between applications that exchange metadata. RDF allows descriptions of Web resources, which is any object with a uniform resource identifier (URI) as its address, to be made available in machine readable form. RDF is an application of XML and extends the XML model and syntax to be specific for describing resources. A resource is can be anything which can be uniquely identified. That is anything which can be assigned a URI. RDF supports a class system where a class specifies a set of properties and constraints on the possible values of those properties. These classes are specified using a schemal language, such as RDF Schema. A collection of property values associated with one or more of these classes is called an RDF description. Each of these properties has a property type and value specified in the associated schema. Schemas are identified uniquely by assigning each a URI. RDF utilizes the namespace facility of XML to point to a URI. Thus, the schema can be accessed at the URI identified by the namespace.
[0004] Even though RDF enables metadata to be understandable to many applications and enables metadata to be infinitely extendable, the use of metadata by photosharing sites would still be problematic. The primary problem is that a user wishing to use these capabilities must understand the technical details of RDF to define his/her metadata.
[0005] One problem with RDF, however, is that the syntax is complicated to learn, especially for a non-computer user. For instance, the following is a portion of the RDF syntax for describing a report:
<Description about = “http://flashpoint.com./report.html”> <DC:Title> Specifying and Assigning Metadata </DC:Title> <DC:Creator> Paul Morris </DC:Creator> <DC:Date> 2001-01-01 </DC:Date> <DC:Subject> Metadata, RDF </DC:Subject> </Description> </RDF>
[0006] Thus, users will not be able to specify metadata to suit his/her own particular needs without becoming an expert in RDF and XML. Further, even if the user took the time to learn RDF and XML, there is currently no mechanism to support for the storage, display, management, or use of this “user defined” metadata.
[0007] Accordingly, what is needed is a system that allows a user to specify metadata for digital files that suits the user's own particular needs, provides storage/retrieval for this metadata, and integrates this metadata into its service, such as image presentation, searching, and grouping. Further, the system must enable this without requiring the user to understand the underlying technologies associated with the metadata schema and specification languages. The present invention addresses such needs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] [0008]FIG. 1 is a block diagram illustrating an online metadata management system in accordance with a preferred embodiment of the present invention.
[0009] [0009]FIG. 2 is a flow chart illustrating the process of allowing users of the metadata management system to manage the metadata library.
[0010] [0010]FIG. 3 is a flow chart illustrating the process of adding a new metadata vocabulary to the metadata library.
[0011] [0011]FIG. 4 is a flow chart illustrating the process of assigning metadata from the vocabulary library to a target resource.
[0012] [0012]FIG. 5 illustrates the process of allowing the user to associate optional metadata with a target resource that already exists in the photosharing site.
SUMMARY
[0013] The present invention provides a method and system for allowing a user to define and use custom metadata. The method and system include providing a network accessible server with a metadata library comprising a plurality of metadata vocabularies. The server allows the user to create a custom metadata vocabulary by displaying a user interface on a client computer in which the user specifies a plurality of properties defining the custom metadata vocabulary. When the custom metadata vocabulary is defined, it is stored in the metadata library for subsequent access. The method and system further allow the user to search the metadata library to select at least one of the metadata vocabularies to apply to an electronic file or other target resource.
[0014] According to the method and system disclosed herein, an online library of metadata vocabularies is provided from which users may create custom vocabularies using a form-driven interface without needing to understand the underlying semantics and syntax of the schema language.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The present invention relates to a method and system for specifying, assigning, and maintaining user-defined metadata in a network-based metadata management system. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiments and the generic principles and features described herein will be readily apparent to those skilled in the art. Thus, the present invention is not intended to be limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and features described herein.
[0016] The present invention provides a metadata management system that allows users of to specify custom metadata, assign the custom metadata to images, and manage the metadata. The present invention provides an online library of metadata vocabularies from which users may create custom vocabularies using a form-driven interface without needing to understand the underlying semantics and syntax of the schema language. In a preferred embodiment the vocabularies are specified using the RDF schema definition language specified by the W3C. (See www.w3.org/RDF/ for details of RDF and RDF schema languages.) Although RDF is expected to become the standard for specification and exchange of metadata on the web, any schema language with similar capabilities will work with this system.
[0017] [0017]FIG. 1 is a block diagram illustrating an online metadata management system in accordance with a preferred embodiment of the present invention. According to the present invention, the system 10 includes a metadata management website 12 that includes a server 14 , and multiple client computers 16 . In a preferred embodiment, the server 14 can be accessed at a specific uniform resource locator (URL) address on the Internet or other network, and users 18 interact with the photosharing site 12 through a standard Web browser 19 .
[0018] In a preferred embodiment, the metadata management system 10 is used in conjunction with a photosharing site and client computers 16 typically store the digital images 20 of a particular user 18 . The digital images 20 are stored as image files that include image data. Each image also has metadata 22 associated with it that describe and categorize the image. The metadata 22 may be associated with the images 20 by the user 18 or automatically by the server 14 as described below.
[0019] According to the present invention, the metadata management site 12 allows users 18 to create, manage, and reuse metadata vocabularies and schema languages without requiring that the users 18 know the details of the metadata schema or exchange syntax. The present invention will be described in terms of a preferred embodiment where the targets to which the metadata is applied are digital images 20 , although the metadata 22 may be applied to any type of digital resource.
[0020] The user 18 may upload the images 20 and the associated metadata 22 to the server 14 for storage. In the alternative embodiment of the present invention, the client computers 16 maintain storage of the actual image data and only the metadata 22 for each image are uploaded to the server 14 .
[0021] In operation, users 18 of the client computers 16 register themselves with the server 14 to become members of the service so that they can specify, assign, and manage custom metadata. Once a member of the service, users 18 can search the server 14 for and reuse custom metadata defined by other users 18 .
[0022] In a preferred embodiment, the server 14 includes a web server application 50 , a metadata vocabulary library 52 , and a user and group account database 54 . The metadata vocabulary library 52 is for storage and management of metadata schemas 84 or vocabularies. The vocabulary library 52 stores both custom metadata vocabularies 84 created by the users 18 , as well as actual metadata values associated with specific images 22 and uploaded from client computers 16 .
[0023] In a preferred embodiment, the vocabulary library 52 includes a universal schema, shared schemas, and private schemas, which in a preferred embodiment are defined using RDF and XML. All images 20 in the system 10 are required to have associated with them metadata 22 specified by the universal schema. Each schema or vocabulary 84 specifies the metadata properties in that vocabulary and specifies constraints that must be enforced in order to comply with the vocabulary. The present invention allows users 18 and groups to define their own schemas, which may include the universal schema and may borrow from other vocabularies 84 .
[0024] According to the present invention, the web server application 50 includes a form-driven user interface 66 that provides users 18 with an easy and intuitive way to define custom metadata vocabularies 84 without specifying the syntax for knowing the underlying schema language.
[0025] For example, the homepage for the photosharing site 12 may display a web page having the following links: “Create A New Metadata Vocabulary” and “Search For A Metadata Vocabulary.” If the user clicks on the link to “Create New Metadata Vocabulary”, then one or more web pages may be displayed with a field for entering the title of the new metadata vocabulary, multiple fields for entering properties for the vocabulary, and fields for entering constraints on the values for each property.
[0026] Assume, for example, that the same a user has taken photos of national parks and wishes to use the photosharing site 12 to create a custom metadata vocabulary for “national parks”. Possible properties the user could define for this new metadata vocabulary include the name of the park, its location (i.e. state and country), the names of objects in the picture, the category (e.g., wildlife, landscape, structure, etc). A possible constraint is that the country must be chosen from a list specified in the vocabulary schema, and the state must be chosen from a list which depends on the value of the country.
[0027] It should be noted that the RDF schema language is not as complete as it could be with respect to specifying constraints. There are good reasons for this as identified by the W3C (see the RDF working group home page). Therefore, according a further aspect of the present invention, the user 18 is provided with the option of associating a vocabulary validator 24 with a newly defined metadata vocabulary 84 in the case were stronger constraints are needed. According to the present invention, the vocabulary validator 24 is a software program that runs on either the server or the client computers 16 that uses a plugin interface provided by the Web application 50 . For example, the plugin interface could define an interface compatible with Java's Enterprise java beans, or use a remote method invocation technology such as RMI or IIOP which makes the location of the validator unknown to the web application invoking it. The Web application 50 passes the metadata corresponding to the custom metadata vocabulary to the vocabulary validator 24 after it has ensured the constraints specified using the RDF schema have been enforced for further constrain enforcement. This process is described in more detail later.
[0028] The Web application 50 provides metadata library management support that allows users with the appropriate permissions to not only add new metadata vocabularies 84 to the library 52 , but also to enter search terms in the user interface 66 to find existing metadata vocabularies 84 and properties. The user 18 may then add one or more existing metadata vocabularies 84 to the user's custom metadata vocabulary, or only select particular properties from the existing metadata vocabularies 84 to add to the user's custom metadata vocabulary. When user has completed the task of entering and/or selecting properties and constraints for the custom metadata vocabulary 84 , the newly created metadata vocabulary is stored in the metadata vocabulary library 52 .
[0029] The user account database 54 stores user account and corresponding contact information and preferences of each registered user 18 . According to the present invention, groups and users may specify their own metadata 22 vocabularies and may share these vocabularies with other users and groups. Users and group administrators may specify one or more vocabularies, which must be supported for images associated with the user and group accounts, respectively. The server 14 and client computers 16 enforce these metadata requirements. Groups of users 18 may also share common policies, which may include permission settings, user interface options, required and optional metadata vocabularies 84 , subscriptions lists, and event/notification policies. In a preferred embodiment access control lists are maintained to control and restrict access. In alternate embodiment, role based permissions as supported by the Java Authentication and Activation Services may be supported.
[0030] The user account database 54 allows mandatory vocabularies 84 to be associated with certain target resources. For example, a particular user 18 may want all of his individual photographs to have a certain set of metadata always supplied. His/her account would be configured to indicate the assignment of metadata supporting the relevant metadata vocabulary 84 is required before the image 20 may be stored on the system 10 . An example of required metadata, might be a vocabulary 84 for data about the owner of the account (e.g name, address, etc). Multiple vocabularies 84 may be required for any given target types.
[0031] Digital still Images 20 need not be the only type of target resources. Examples of other types of image files for which required vocabularies may be specified include multiple image files, such as timelapse images, burst images, panarama images, etc. Non-image target resources may also be supported, such as sound files, movies, and text documents. The present invention applies to any resource that could conceivably have metadata associated with it.
[0032] [0032]FIG. 2 is a flow chart illustrating the process of allowing users of the metadata management system to manage the metadata library 52 . Once the user logs-in, the Web application 50 displays one or more web pages that allows the user 18 to perform the following high-level functions. One management function is to allow the user to create vocabularies 84 to be added to the library 52 in step 106 (described further in FIG. 3).
[0033] The second management function is to allow the user 18 to add references to metadata vocabularies existing elsewhere on the web to the library 52 in step 110 so they may be found by the search facilities provided by the Web application 50 . To add a reference to a metadata vocabulary existing external to the metadata library 52 , user 18 enters the name and URI for the metadata vocabulary in one of the user interface forms in step 112 , and clicks a link or button to create a new entry in the metadata library 52 in step 114 . See www.w3.org/RDF/ for details of how a vocabulary can reference elements of another vocabulary in order to borrow from it.
[0034] The third management function is to allow the user 18 to set access permissions for the metadata vocabularies 84 in the metadata library 52 in step 118 . This is accomplished by selecting one or more metadata vocabularies 84 from the vocabulary library 52 in step 120 and setting the user permissions of the selected metadata vocabularies 84 in step 116 .
[0035] [0035]FIG. 3 is a flow chart illustrating the process of adding a new metadata vocabulary 84 to the metadata library 52 . In response to the user 18 choosing to create a metadata vocabulary 84 in step 106 of FIG. 2, the Web application 50 gives the user 18 a choice to reuse properties from an existing vocabulary in step 206 or create a new property in step 214 . The user 18 may create new properties to be contained in the vocabulary by entering the property name and specifying the constraints, if any, for the possible values the property may contain in step 216 and 218 .
[0036] For each new property the user 18 creates, the Web application 50 prompts the user 18 for the name of the property and allows the user 18 to select from a list of property types String, List, Boolean, Numeric, etc. The choices are limited to what the underlying specification language supports. Depending on the type, the Web application 50 may prompt the user 18 to provide additional constraints, such as the list of possible values for a list type or a range for a numeric range.
[0037] If the user 18 chooses to reuse an existing vocabulary 84 , then a search facilities is presented in step 208 that allows the user 18 to locate existing vocabularies 84 based on user supplied criteria, such as the vocabulary identifier (i.e., its URI), the vocabulary's name, the name(s) of properties contained in the vocabulary, the owner of the vocabulary, or the intended target types of a vocabulary. That is, the library 52 supports metadata about the metadata vocabularies 84 . The search facility makes the vocabularies 84 easily browsable. The system 10 may at the option of the user 18 extend its search to include other metadata libraries (aka registries) as more of these libraries appear on the web.
[0038] After the user enters search terms and finds existing vocabularies, the user 18 may select one or more properties from these vocabularies 84 in step 210 to add to the metadata vocabulary 84 being created. The user may optionally add additional constraints to the borrowed property (as allowed by RDF) in step 212 .
[0039] As an example of reusing properties from an existing vocabulary and searching, consider a user who wants to create a metadata vocabulary 84 for describing pictures of his pets. He may begin by borrowing properties from the well-known Dublin Core metadata vocabulary, such as Title, Subject, and Description. He would do this by locating the Dublin core vocabulary using the search facility. In the search facility, he can enter the ID of the Dublin Core (i.e., its URI) or enter the names of one or more properties in the Dublin Core such as “subject”. Once the Dublin Core vocabulary is located and selected, the Web application 50 would display the properties available from the vocabulary allowing the user to select which elements to borrow. The user 18 may repeat this borrowing process from other vocabularies 84 . As the user 18 borrows properties, the Web application 50 allows the user to specify additional constraints. For example, the “Subject” property in the Dublin Core is a string (typically a string of keywords). The user 18 could select to restrict the string to one or more of a series of words from a list he specifies. When subsequently applying his custom metadata to images of his pets, the Web application 50 would display the list of pet names for the user to select from.
[0040] As an additional option, the user 18 may supply a validator 24 to enforce contraints beyond those supported by the specification language. The validator 24 is a software program that supports a plugin API provided by the metadata library 52 . The validator 24 is called when metadata associated with the vocabulary is created or changed, but after the constraints enforced by the specification language have been verified.
[0041] The processes of reusing existing vocabularies 84 and creating new properties may be repeated as needed until the user 18 is satisfied with the new metadata vocabulary 84 in step 202 . When the new metadata vocabulary 84 is complete, the metadata vocabulary 84 is named and saved in the metadata library 52 in step 204 .
[0042] [0042]FIG. 4 is a flow chart illustrating the process of assigning required metadata from the vocabulary library to a target resource. When the Web application 50 receives a target resource to be added to the photosharing site 12 from the user 18 , the Web application 50 checks the user's account and the relevant group accounts that the user is a member of and retrieves the required vocabularies 84 specified for the type of target resource in step 302 . As stated above, any resource type may be supported, including images, sound files, movies, text files, and so on).
[0043] Because the metadata vocabularies 84 often borrow properties from one another, the Web application 50 merges the required metadata vocabularies 84 retrieved from the library 52 in step 304 before prompting the user to enter values for the properties. The merging process performs two primary functions. First, it removes duplicate properties (that result from the borrowing of properties among vocabularies 84 ). Second, because the same property may have different sets of constraints specified by different vocabularies 84 , the Web application 50 ensures that policy for conflicting constraints is enforced. In a preferred embodiment, the most restrictive constraints are applied. In an alternate embodiment, the Web application 50 may allow the user to enter values that meet either constraint. A third possibility for constraint policy is to always choose the constraints in one particular vocabulary 84 over another. For example, two required vocabularies 84 may both borrow the property “subject” from the Dublin Core. Each of these vocabularies 84 may have specified additional constraints on what the value of “subject” may be.
[0044] After merging vocabularies 84 , the Web application 50 builds the user interface by generating forms for metadata assignment in step 306 through which the user may enter values for the assigned metadata. In a preferred embodiment, the interface is a series of one or more forms displayed in the web browser 19 . In a preferred embodiment, XSLT is used to transform the RDF schema specification into XHTML forms for display in the user's web browser 19 . The user 18 is then allowed to navigate through the form(s) entering data in step 308 . The forms may display additional comments provided by the vocabularies 84 to aid the user 18 in entering the data values. As the user moves to an input field for a given property, the Web application 50 uses the constraints defined for the property to determine the correct form element to use for data input for any given property (a test field, a selection list, a choice list, and so on).
[0045] As the user 18 enters values for the metadata, the Web application 50 validates the metadata values based on the vocabulary constraints and optionally supplied vocabulary validator 24 (s) in step 310 . When the data is valid and the user 18 is finished entering metadata values, the Web application 50 associates the metadata with the target resource and saves in step 312 .
[0046] [0046]FIG. 5 illustrates the process of allowing the user 18 to associate optional metadata with a target resource that already exists in the management site 12 . In other words, this process allows the user 18 to add metadata for the target resource that was not otherwise required for that resource type. In a preferred embodiment, the user 18 may add metadata to any target to which he/she has access. The user 18 first searches and/or browses for metadata vocabularies 84 as needed to add the desired metadata to the target in step 402 . The user 18 then selects vocabularies 84 to use in step 404 . Note: If the user 18 can't find the needed properties in existing vocabularies 84 the user 18 can create a new one, as described with reference to FIG. 3.
[0047] After the user has selected vocabularies to use, the process proceeds as described with reference to FIG. 4: merging the vocabularies (step 406 ), generating forms for metadata assignment (step 408 ), displaying the forms and accepting user input (step 410 ), and validating the metadata values based on the vocabulary constraints and optional vocabulary validator 24 s (step 412 ). The user 18 may continue by searching for more vocabularies to add to the target resource in step 402 . When user 18 is done in step 414 , the metadata is associated with the target resource and saved in step 416 .
[0048] As an example of adding optional metadata to images consider the following example. Assume that the user 18 has added an image of a family with mountains in the background to the system 10 . Assume further that the user 18 has defined a private schema that includes the universal schema, borrows from a shared schema defined for family metadata, and has added additional metadata for the user's 18 private use. Another user 18 may discover the image, perhaps through a search using fields in the universal schema. Seeing the mountains in the picture and being an avid fan of nature photography this user creates nature metadata to associate with image using a shared schema defined for nature photographs. The user then uploads this metadata for the image to the server 14 . Other users constructing searches built using one or more of these vocabularies (universal, family, user's private extensions, and nature) will be able to find image if the search criteria match.
[0049] According to the present invention, the photosharing system allows users to create custom metadata and to make the custom metadata available for other users in the system to use. The schema definitions are not limited by the system 10 . Further, the system allows the users to add and reuse the metadata stored in the system without requiring users to know underlying details regarding the schema language and syntax.
[0050] A method and system for specifying, assigning, and maintaining user defined metadata in a network-based metadata management system has been disclosed. The present invention has been described in accordance with the embodiments shown, and one of ordinary skill in the art will readily recognize that there could be variations to the embodiments, and any variations would be within the spirit and scope of the present invention. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims. | 4y
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CROSS-REFERENCE
This application is the US national stage application of International Application No. PCT/DE02/00159, which claims priority to German patent application nos. 101 04 102.0 and 101 26 708.8.
TECHNICAL FIELD
The present invention relates to methods and apparatus for recognizing the synchronization position and the end of the synchronization operation of an automatic shiftable transmission having an electrically-driven shift actuator.
BACKGROUND OF THE RELATED ART
Shiftable transmissions for motor vehicles have long been known in many different forms. In the past, a shiftable transmission was primarily understood to be a manually-shiftable transmission, in which the driver of a motor vehicle equipped with this type of shiftable transmission selects the shift path and performs the gear shift operation by hand via a shift lever. In addition to these manually-shiftable transmissions, it has also been known in the meantime to use automated shiftable transmissions when the operation of selecting and shifting the selected gear stage is executed, for example, according to programmed control by actuators provided in the shiftable transmission.
During operation, an automated shiftable transmission of this kind is subjected to normal wear and tear on its component parts, e.g., the synchronizing means, which wear and tear can lead to displacement of the middle synchronization position. The middle synchronization position is defined herein as a mean position value during the synchronization operation. The blocking position of the synchronizing means can vary somewhat from shift operation to shift operation, because the shift sleeve can engage in the synchronizer ring differently and unpredictably from shift operation to shift operation.
However, accurate knowledge of the synchronization position is important, as the synchronization position should be quickly reached by the shift actuator in order to shorten the shift time. In addition, the shift actuator should also quickly arrive at its end position (i.e., the gear engaged position) at the end of the synchronization operation.
When the shift actuator reaches the synchronization position, the synchronizing means exerts a blocking effect on the shift actuator as a result of the synchronization operation, which leads to an increase in the load current of the actuators. It has already been known to detect the start of the synchronization by this increase in the load current.
However, detecting the load current is comparatively complicated and expensive and furthermore, can only produce a result with regard to a change of the synchronization position within the bounds of a continuous determination of the actuator position, as the position of the actuator when the load current increases must be known.
SUMMARY OF THE INVENTION
Thus, an object of the present invention is to provide methods and apparatus, by which, in a less expensive manner, a change of the synchronization position and the end of the synchronization operation can be recognized.
The invention is achieved by the solution of this object in accordance with the features and aspects of the present teachings provided herein. Advantageous embodiments of these features and aspects are described further below and a representative apparatus for performing methods according to the present teachings is shown in FIG. 5 . Reference to elements shown in FIG. 5 is provided throughout this summary and the following detailed description.
According to the invention, methods and apparatus for recognizing the synchronization position and the end of the synchronization operation of an automated shiftable transmission 11 having an electromotive shift actuator 13 are provided, in which the rotational speed of the shift actuator 13 is detected and the synchronization position, as well as the end of the synchronization operation, are determined based upon changes in the rotational speed.
By detecting the rotational speed of the shift actuator 13 over time, it is possible to determine the path along which the shift actuator 13 has moved. Therefore, even without a continuous determination of the actuator position, according to this method, it is possible to determine that the synchronization position that has been reached when the rotational speed of the shift actuator 13 undergoes a predetermined threshold value (rotational speed) change within a predetermined time interval.
The rotational speed of the shift actuator 13 can be detected by sensors 14 that generate a predetermined number of pulses per revolution of the actuator shaft. By measuring the pulse frequency and/or the timed pulse interval, it is possible to determine the rotational speed of the shift actuator 13 . It is also possible to determine geometric intervals by adding the pulses.
Therefore, according to the invention, if it is determined that the rotational speed of the shift actuator 13 has experienced a clear decline (reduction) within a certain time interval, then it is concluded that the synchronization position has been reached.
During the synchronization operation, a synchronizing means 12 temporarily exerts a blocking effect against further movement of the shift actuator 13 . When the blocking effect is released at the end of the synchronization operation, the rotational speed of the shift actuator 13 will increase again.
Because the wear behaviour of the automated shiftable transmission 11 can lead to gear-specific changes in the shift characteristics of the transmission 11 , it is proposed according to the invention that the synchronization position is determined independently of the end of the synchronization operation for each gear stage of the automated shiftable transmission 11 .
By using such a method according to the invention, it is therefore possible to identify gear-specific changes of the synchronization position and also to determine the gear-specific end of the synchronization operation.
Changes in the synchronization position of the relevant gear stages of the automated shiftable transmission 11 during operation can therefore be taken into account by determining the synchronization position and by using this synchronization position as the assumed target synchronization position during the next gear change operation for the relevant gear stage in order to control the shift actuator 13 . Similarly, by continuously monitoring the rotational speed of the shift actuator 13 , it is possible to determine whether the synchronization operation has concluded. The end of the synchronization operation can be recognized, e.g., by a parabolic or a generally linear increase in the rotational speed of the shift actuator 13 over time.
In this way, it is therefore possible to determine (a) changes in the synchronization position in the direction towards the neutral position of the transmission or away from same, and also (b) changes in the time duration of the synchronization operation. Thus, for example, if the current supply to the shift actuator 13 is increased before the conclusion of the synchronization operation, only an insignificant acceleration of the shift actuator 13 , and thus a small change of its rotational speed, results. Consequently, it can be concluded from this small speed change that the synchronization operation has not yet ended. This knowledge can then be used during a subsequent gear change operation and a corresponding synchronization so as to accordingly delay the start of the increase of the current supply to the shift actuator 13 , thereby avoiding a stretching of the shift elasticity.
Conversely, if the end of the synchronization is known, it is therefore possible to increase the load current for the shift actuator 13 without any further delay, so that the end position of the shift actuator 13 on its travelling path to the engaged gear stage can be rapidly reached. This leads to a shortening of the travelling time of the shift actuator 13 to reach the end position and thus to a shortening of the time required for completion of the gear shift operation.
It is thereby proposed according to the invention that the determined synchronization position is stored in a memory device 16 . Then, at the next gear change operation, the determined synchronization position is read out from the memory device 16 and is used as the target synchronization position for movement to the synchronization position effected by the shift actuator 13 . For this purpose, a volatile memory can be provided and the determined synchronization position is stored in the volatile memory during operation of the shiftable transmission. Therefore, the gear-specific last synchronization positions, which are in use when the automated shiftable transmission equipped motor vehicle is stopped, can be utilized during the next vehicle driving operation. These values may then be written into a non-volatile memory after stopping the vehicle, e.g., which vehicle stoppage is controlled by an ignition signal, and then read out during the next vehicle start-up so as to be again stored in the volatile memory.
The stored synchronization position is thereby up-dated with the actually determined synchronization position when the stored synchronization position deviates from the determined synchronization position. Therefore, changes in the synchronization position will not lead to changes in the shift characteristics of the transmission 11 .
It is further proposed according to the invention that the up-dating is performed when the determined synchronization position changes, as compared with the stored synchronization position, for the individual gear stages of the automated shiftable transmission 11 , in different directions in relation to the neutral position. In other words, this means, e.g., that an up-date will be performed when the actually determined synchronization position of the first gear is displaced towards the neutral position and the actually determined synchronization position of the third gear is displaced in a direction away from the neutral position
On the other hand, when the gear-specific synchronization positions for all gears have changed or have been displaced in the same direction, it can be assumed that the entire shift pattern has moved altogether. Therefore, an adaptation (change) of the synchronization position for the individual gear stages is not necessary in this case.
According to a further development of the method according to the invention, it is further proposed that the up-date is performed only when the shiftable transmission 11 has warmed up to its operating temperature, wherein a sensor is provided on the shiftable transmission in order to detect the temperature thereof and/or a predetermined operating time of the shiftable transmission is allowed to elapse in order to ensure that the transmission has been sufficiently operated to have reached its normal operating temperature. An allowance is thereby made of the fact that, if the operating parameters of the automated shiftable transmission 11 do not remain substantially the same, such as e.g. the oil viscosity within the transmission 11 , an adaptation mistake could result. Such a mistake can be avoided by waiting to perform the up-date until the transmission 11 has warmed up to its operating temperature.
The stored synchronization position is used to control the shift actuator 13 , so that the shift actuator 13 reduces the speed of the travelling movement of the shift elements in the shiftable transmission 11 before reaching the target synchronization position. A large mechanical strain on the shift actuator 13 and shift elements is thereby avoided.
According to another aspect of the present teachings, when a change (displacement) of the synchronization position in relation to the neutral position is determined to exceed a predetermined threshold displacement distance, an action notification is issued. This action notification can be, e.g., a corresponding entry in the fault memory of the vehicle. In this case, when the next vehicle maintenance is done, suitable remedial measures can be performed, such as e.g., replacing worn synchronizing rings in the transmission 11 .
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be explained in further detail with reference to the drawings in which:
FIG. 1 shows a graphic illustration of the position of the shift actuator 13 over time during a transmission synchronization operation.
FIG. 2 shows an illustration to explain the identification of displacements of the synchronization position with respect to the neutral position and the gear engaged position.
FIG. 3 shows an illustration for explaining a unidirectional displacement of the entire shift pattern.
FIG. 4 shows an illustration for explaining the importance of the synchronization position.
FIG. 5 shows a representative apparatus for performing the methods described herein.
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1 , the curved lines 1 and 2 each represent the shift operation when a “neutral-distant” synchronization position is present, while the curved lines 3 and 4 each represent the shift operation for a “neutral-close” synchronization position. According to the term “neutral-distant,” a change (displacement) of the synchronization position, as determined by a controller 15 , away from the neutral position is meant and, according to the term “neutral-close,” a change (displacement) of the determined position in a direction towards the neutral position is correspondingly meant.
As shown in FIG. 1 , the shift actuator 13 , as illustrated over time, is at first moved linearly and is then braked near the synchronization position or synchronization operation. A blocking effect is exerted against further movement of the shift actuator 13 during the synchronization operation. Therefore, this means that the shift actuator 13 is braked and becomes practically stationary until time point A. However, a force is continued to be applied to the shift actuator 13 and the continued application of the force leads, after time point B, to an acceleration of the shift actuator 13 , and thereby an increase in the rotational speed of the shift actuator 13 .
Curved line 1 shows a parabolic-shaped path with a high acceleration, whereas curved line 2 represents a path with a reduced acceleration. Because the beginning of the controlled acceleration of the shift actuator 13 according to curved line 2 would be selected too early, the blocking effect of the synchronization would still be exerted against the shift actuator 13 and thus only a slight acceleration of the shift actuator 13 would result. By monitoring the rotational speed of the shift actuator 13 during a next following shift operation, a path can therefore be utilized according to curved line 1 , by which the controlled acceleration starts later, i.e., after the blocking action of the synchronization has ceased. This later acceleration leads to an overall faster shift operation, because the acceleration is greater, and also leads to a reduction of the mechanical strain on the shift actuator 13 and the synchronizing means 12 , because the shift actuator 13 does not work against synchronization while the synchronizing means 12 is still exerting the blocking effect.
Curved lines 3 and 4 of FIG. 1 show similar conditions with a synchronization position closer to the neutral position. By detecting the end of the synchronization operation, it is thus also possible with a synchronization position lying closer to the neutral position to change the position of the shift actuator 13 , as expressed by curved line 3 , and thus to attain a reduction in the shift time. In comparison, curved line 4 shows again, for clarity, a premature assumed end of the synchronization operation with a corresponding lengthening of the time period until reaching the end position of the shift actuator 13 , i.e., the “gear engaged” position.
Using two examples (cases), FIG. 2 shows that a change in the synchronization position can be concluded or recognized.
In the example illustrated in Case 1, the actual synchronization position (ST) lies farther away from the neutral position than the synchronization position (SV), which was utilized or assumed by the controller 15 (e.g., stored in memory 16 ), which are shown in FIG. 5 . This fact is concluded because the stationary position (SS) was determined to be above the utilized (stored) synchronization position SV. This stationary position (SS) is also shown in FIG. 1 and corresponds to the position of the shift actuator 13 after braking (i.e., the horizontal portion of the curved lines shown in FIG. 1 ) and is utilized during the synchronization operation.
At the end of the synchronization operation, a large acceleration (A>) is apparent, which corresponds in FIG. 1 to the portion of curved lines 1 – 4 that is characterized as a steep parabola, so that an adaptation, i.e. a correction of the assumed synchronization position (SV) utilized by the controller 15 , is appropriate. This determined synchronization position can then be stored as the new target synchronization position in the memory 16 of the controller 15 .
Case 2 shows that the actual synchronization position (ST) lies closer to the neutral position than the assumed (stored) synchronization position (SV). A low acceleration (A<) is present. Because the assumed synchronization position (SV) was assumed to be above the stationary position (SS) and the actual synchronization position (ST), the actuator 13 has had to work against the blocking effect of the synchronizing means 12 during the synchronization operation. An adaptation of the assumed (stored) synchronization position (SV) in the direction closer to the neutral position is thus appropriate.
FIG. 3 shows an illustration to explain a unidirectional displacement of the entire shift pattern. In relation to the neutral position, a change (displacement) of the synchronization position for each forward gear has occurred in the same direction, which direction change is shown by the upwardly directed arrows. Therefore, it can be concluded that the entire shift pattern has moved altogether and an adaptation of the assumed synchronization position (SV) by the controller 15 is thus not necessary.
Lastly, FIG. 4 serves to explain the importance of the synchronization position. The controller 15 uses the assumed synchronization position SV to brake the shift actuator 13 just before reaching the stationary position SS. This acceleration/braking pattern enables arrival at the stationary position SS as fast as possible, thereby shortening the time for the gear change operation, without however “moving into” the synchronization position with a still high speed of the shift actuator, as this would result in a “bounce back” of the shift actuator 13 , due to the blocking effect being exerted by the synchronizing means 12 .
If the assumed synchronization position SV used by the controller 15 is located too far in the neutral-distant direction (i.e., away from the neutral position), then no braking takes place before reaching the actual synchronization position ST and the shift actuator 13 must absorb the forces that are generated by the direct contact with the synchronizing means 12 , which leads to the above-noted bounce-back. With a too neutral-close assumed synchronization position SV (i.e., the assumed synchronization position SV is too close to the neutral position), the result is a premature braking of the shift actuator 13 . In this case, the shift actuator 13 will “creep” slowly towards the stationary position SS and the duration of the drive force interruption during a gear change operation will increase accordingly. These changes will have the effect of reducing shift comfort. But, with a correctly assumed synchronization position SV (e.g., as a result of an adaptation performed at the previous shift operation), the high mechanical strain on the shift actuator 13 , on the one hand, ceases and on the other hand, a short time results for the gear change operation. Consequently, the drive force interruption is relatively short.
For further features of the invention, which have not been explained in more detail above, reference is expressly made to the claims.
The patent claims filed with the application are proposed wordings without prejudice to obtaining broader patent protection. The applicant reserves the right to claim further combinations of features disclosed until now only in the description and/or drawings.
References made in the dependent claims refer to the further design of the subject of the main claim using the features of the relevant dependent claims; they are not to be regarded as dispensing with obtaining an independent subject protection for the combination of features of the dependent claims referred to.
Since the subject matter of the dependent claims can form independent inventions, as compared with prior art known by the priority date of this application, the applicant reserves the right to make them the subject of independent claims or divisional applications. They can also contain independent inventions that have a configuration independent of the subjects of the preceding dependent claims.
The embodiments are not to be regarded as restricting the invention. Rather, numerous modifications and amendments are possible within the scope of the present disclosure, in particular, those variations, elements and combinations and/or materials that can be derived by the expert as a solution of the object, for example, by combination or modification of individual features, elements or method steps contained in the drawings and described in connection with the general description and embodiments as well as claims, and by combinable features that lead to a new subject or new method steps or sequence of method steps, insofar as they relate to manufacturing, test and work methods. | 4y
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This application is a divisional of application Ser. No. 08/834,454, filed Apr. 15, 1997 (which is incorporated herein by reference in its entirety), now U.S. Pat. No. 6,071,116.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to gaseous fuel burners. More specifically the invention relates to energy efficient burning of fuel using such burners.
2. Related Art
Oxy-fuel burners and technologies are being used more and more in high temperature processes such as, glass manufacturing, incineration of wastes, steel reheating, aluminum smelting, and iron smelting, for the benefits they provide:
high heat transfer rates;
fuel consumption reductions (energy savings);
reduced volume of flue gas;
reduction of pollutants emission, such as oxides of nitrogen (NOx), carbon monoxide (CO), and particulates.
Oxygen used in these high temperature processes can be technically pure oxygen (99.99%) or various grades of industrial oxygen, with purities down to 80%.
Despite the reduction of the flue gas volume that the substitution of combustion with air by combustion with pure oxygen yields, a significant amount of energy is lost in the flue gas, especially for high temperature processes. For example, in an oxy-fuel fired glass furnace where all the fuel is combusted with pure oxygen, and for which the temperature of the flue gas at the furnace exhaust is of the order of 1350° C., typically 30% to 40% of the energy released by the combustion of the fuel is lost in the flue gas. It would be advantageous to recover some of the energy available from the flue gas in order to improve the economics of operating an oxy-fuel fired furnace.
A number of techniques to recover energy from flue gases are available. Those techniques have been proven or described for air-fuel fired furnaces. Similar techniques have yet to be demonstrated for oxy-fuel furnaces, because of difficulties that will become apparent from the following discussion.
One technique consists in using the energy available in the flue gas to preheat and dry out the raw materials before loading them into the furnace. In the case of glass melting, the raw materials consist of recycled glass, commonly referred to as cullet, and other minerals and chemicals in a pulverized form referred to as batch materials that have a relatively high water content. The energy exchange between the flue gas and the raw materials is carried out in a batch/cullet preheater. Such devices are commonly available, for example from Zippe Inc. of Wertheim, Germany. Experience shows that this technology is difficult to operate when the batch represents more than 50% of the raw materials because of a tendency to plug. This limits the applicability of the technique to a limited number of glass melting operations that use a large fraction of cullet. Another drawback of this technique is that the inlet temperature of the flue gas in the materials preheater must be generally kept lower than 600° C. In the case of an oxy-fuel fired furnace where the flue gas is produced at a temperature higher than 1000° C., cooling of the flue gas prior to the materials preheater would be required.
Energy efficiency of air-fuel furnaces is greatly improved if the energy available from the flue gas is used to preheat the combustion air. Recuperators, where some of the heat from the flue gas is transferred to the combustion air in a heat exchanger, and regenerators, where some of the heat from the flue gas is accumulated in a ceramic or refractory material for later preheating of the combustion air, are the most common techniques encountered in the industry for this purpose. Such techniques are difficult to apply in the case of oxy-fuel fired furnaces because of the hazards of handling the extremely reactive hot oxygen.
Thermochemical energy recovery (also known as fuel reforming) is another technique that consists in increasing the heat content of a fuel by reacting it with steam or carbon dioxide or a mixture of the two in a reactor (reformer), and generating a combustible mixture that contains hydrogen (H 2 ) and carbon monoxide (CO) and has a higher heat content than the initial fuel. The reforming reaction occurs at high temperature (typically 900° C.), is endothermic, and takes advantage of the high temperature of the flue gases to generate the high temperature gases required by the process, and to provide the energy for the reforming reaction. Practically, the fuel consumption in a glass plant is not high enough to provide an economical justification to the high capital cost of installing a fuel reforming system. The complexity of the reformer, and safety constraints linked to handling hot H 2 and CO, are additional drawbacks of this technology. In the case of oxy-fuel furnaces, the energy available from the flue gas is typically not sufficient for reforming all the fuel, and an additional energy source is generally required in addition to the flue gas, which adds to the complexity of the apparatus.
Co-generation of power and heat (i.e. the simultaneous generation of electricity and steam using the hot flue gases) is another technique that is available to recover the energy from flue gas, and use it for other purposes than recycling into the furnace. The disadvantage of this approach is that the capital costs tend to be very high. This option is, however, viable for very high heat output furnaces (those which produce greater than 30 megawatts of power).
With stricter environmental regulations, a number of industries are required to install pollution abatement systems. Those devices typically cannot handle the very high temperatures found at the exhaust of an oxy-fuel furnace used for a high temperature process. For instance, at the outlet of an oxy-fuel fired glass tank furnace, the temperature typically ranges from about 1300° C. to about 1450° C. Before the flue gases can be treated by the pollution abatement system (which can be an electrostatic precipitator or a baghouse in the case of cleaning the flue gas from particulate matter) it is highly preferable to cool down the gases. This is generally performed by diluting the gases with ambient air, or spraying of water that vaporizes upon contact with the hot gases, to yield a cooling of the gases, or by a combination of these techniques. Dilution with air increases the amount of gas to be treated by the pollution abatement system, which increases its cost. Water injection elevates the dew point of the gases and forces the pollution abatement device to operate at high temperature. This is especially true for oxy-fuel fired furnaces where the water content of the flue gases can be as high as 60% by volume.
What is needed then is a method and apparatus (or system) which efficiently and at relatively low capital cost recovers at least a portion of the available heat which otherwise is wasted to the atmosphere, particularly in high temperature processes where oxy-fuel burners are employed, and simultaneously cools down the flue gases.
SUMMARY OF THE INVENTION
In accordance with the invention, methods and apparatus are presented which combine one or more oxy-fuel burners operating with either hot oxidant, hot fuel, or both, with use of a primary heat exchanger disposed in a flue gas channel. As used herein the term “oxidant” is used to mean either pure oxygen (as defined in the industry) or oxygen enriched air. “Process gas” as used herein refers to gases and particles including all gases which are not combustion products. The primary heat exchanger employs an intermediate safe fluid (air or nitrogen for example) to transfer at least a portion of the heat from the hot flue gases to either the oxidant, the fuel, or both, used in the burners. The function of the primary heat exchanger is to transfer at least a portion of the heat from the hot flue gases to the intermediate safe fluid (hereinafter referred to simply as the intermediate fluid). Removing the energy of the flue gases in a heat exchanger is a convenient means of cooling of the flue gases without increasing the quantity of flue gases or increasing the water content of these gases. The dimension of pollution abatement device that may be installed before the gases are exhausted to the atmosphere can be smaller, and the cost of the equipment can be lower. Some of the heat content of the intermediate fluid is then transferred to the oxidant, fuel, or both as explained herein. The hot oxidant and the hot fuel are combusted in the furnace using the oxy-fuel burners.
A first aspect of the invention is an apparatus suitable for recovery of heat from hot flue gases, the apparatus comprising:
(a) at least one primary means for transferring heat between a hot flue gas having a hot flue gas temperature, and an initially cold intermediate fluid, the initially cold intermediate fluid having a cold intermediate fluid temperature which is less than the hot flue gas temperature, to create a hot intermediate fluid and to cool the hot flue gas;
(b) one or more oxidant-fuel burners which create the main flow of the hot flue gas, the oxidant-fuel burners being associated with preheater means in which either a fuel or an oxidant is preheated by the hot intermediate fluid, and thus creating a cooled intermediate fluid, and;
(c) transport means for transporting the hot intermediate fluid to at least one of the preheater means.
Preferred apparatus of the invention are those wherein the intermediate fluid is a gas, more preferably air. Other possible fluids include steam, carbon dioxide, nitrogen, or mixtures thereof, or even liquids.
In this and other aspects of the invention it is possible for the hot intermediate fluid to transfer heat to the oxidant or the fuel either indirectly by transferring heat through the walls of a heat exchanger, or a portion of the hot intermediate fluid could exchange heat directly by mixing with the oxidant or the fuel. In most cases, the heat transfer will be more economical and safer if the heat transfer is indirect, in other words by use of a heat exchanger where the intermediate fluid does not mix with the oxidant or the fuel, but it is important to note that both means of exchanging heat are contemplated by the present invention. Further, the intermediate fluid could be heated by the hot flue gases by either of the two mechanisms just mentioned.
In one preferred apparatus of the invention, the cooled intermediate fluid is transported back to the primary means for transferring heat.
Preferably, the primary means for transferring heat comprises one or more heat exchangers selected from the group consisting of ceramic heat exchangers, known in the industry as ceramic recuperators, and metallic heat exchangers further referred to as metallic recuperators.
Preferred apparatus in accordance with the invention are those wherein the primary means for transferring heat are double shell radiation recuperators.
Preheater means useful in the invention comprise heat exchangers selected from the group consisting of ceramic heat exchangers, metallic heat exchangers, regenerative means alternatively heated by the flow of hot intermediate fluid and cooled by the flow of oxidant or fuel that is heated thereby, and combinations thereof. In the case of regenerative means alternately heated by the flow of hot intermediate fluid and cooled by the flow of oxidant or fuel, typically and preferably there is present two vessels containing an inert media, such as ceramic balls or pebbles. One vessel is used in a regeneration mode, wherein the ceramic balls, pebbles or other inert media are heated by hot intermediate fluid, while the other is used during an operational mode to contact the fuel or oxidant in order to transfer heat from the hot media to the fuel or oxidant, as the case might be. The flow to the vessels is then switched at an appropriate time.
One preferred apparatus in accordance with this aspect of the invention is that wherein the hot intermediate fluid exchanges heat with the fuel and oxidant in parallel preheater means, in other words, hot intermediate fluid is split into two streams, one stream exchanging heat with the fuel in a first burner preheater means, the second stream exchanging heat with the oxidant in a second burner preheater means. Alternatively, and perhaps more preferred for safety reasons, the intermediate fluid exchanges heat first with the oxidant in one or more oxidant preheaters, and then with the fuel in one or more fuel preheaters in series exchangers.
Preferably, the apparatus of the invention comprises burners where oxidant and fuel are injected separately in the furnace where they mix in such fashion to form a flame. Yet another preferred apparatus of the invention comprises burners wherein oxidant and fuel are injected in the furnace through a burner block.
Another aspect of the invention is an apparatus suitable for recovery of heat from hot flue gases, the apparatus comprising:
(a) at least one primary means for transferring heat between a hot flue gas having a hot flue gas temperature, and an initially cold intermediate fluid, the initially cold intermediate fluid having a cold intermediate fluid temperature which is less than the hot flue gas temperature, to create a hot intermediate fluid and to cool the hot flue gas;
(b) one or more oxidant-fuel burners which create the main flow of hot flue gas, the oxidant-fuel burners having a fuel path for a fuel, an oxidant path for an oxidant, and a hot intermediate fluid path, wherein the hot intermediate fluid exchanges heat with either the oxidant, the fuel, or both the oxidant and the fuel, to create a cooled intermediate fluid; and
(c) transport means for transporting the hot intermediate fluid to the oxidant-fuel burners.
As with the first aspect of the invention, preferably the intermediate fluid is air although other gases such as steam, carbon dioxide, nitrogen, or mixtures thereof, and liquids may be used.
In one preferred apparatus of the invention, the cooled intermediate fluid is transported back to the primary means for transferring heat from the hot flue gas to the initially cold intermediate fluid.
In this aspect of the invention, the fuel path, oxidant path, and the hot intermediate fluid path are preferably defined by bores through a furnace refractory wall, that is, the burner is preferably integral with the furnace wall in that it is comprised of the same material (refractory or ceramic). Alternatively, the fuel path, oxidant path, and the hot intermediate fluid path are preferably defined by bores through a burner block as is known in the burner art, the burner block being positioned in a furnace wall, Such a burner block is described, for example, in U.S. Pat. Nos. 5,984,667 and 5,975,886, both of which are incorporated herein by reference.
A preferred apparatus in accordance with this aspect of the invention is that wherein the hot intermediate fluid exchanges heat with the fuel and oxidant in parallel preheaters, in other words, hot intermediate fluid is split into two streams, one stream exchanging heat with the fuel in a first burner heat exchanger, the second stream exchanging heat with the oxidant in a second burner heat exchanger.
Alternatively, and perhaps more preferred, the intermediate fluid exchanges heat with the fuel and oxidant in series exchangers, with the hot intermediate fluid first exchanging heat with the oxidant, and then the fuel, this being deemed safer.
When the intermediate fluid is air, and the oxidant for combustion is oxygen, the hot air can be advantageously used as the combustion oxidant by directing the hot air flow to the burners, when the oxygen supply is interrupted.
The third embodiment of the invention is a method of recovering heat from hot flue gases created from combustion of a fuel with an oxidant, the method comprising the steps of:
a) combusting the fuel with the oxidant in one or more oxidant-fuel burners to create the main flow of hot flue gas;
b) flowing a hot flue gas and an initial intermediate fluid having an initial intermediate fluid temperature through primary means for transferring heat between the hot flue gas and the initial intermediate fluid to create a hot intermediate fluid;
c) transferring heat from the hot intermediate fluid to either the fuel, the oxidant, or both, by flowing the hot intermediate fluid through one or more preheater means in which either the fuel, the oxidant, or both are preheated with the hot intermediate fluid prior to the fuel and the oxidant entering one or more oxidant-fuel burners which create said main flow of hot flue gas.
The fourth embodiment of the invention is a method of recovering heat from hot flue gases created from combustion of a fuel with an oxidant, the method comprising the steps of:
a) combusting the fuel with the oxidant in one or more oxidant-fuel burners to create the main flow of hot flue gas;
b) flowing a hot flue gas and an initial intermediate fluid, having an initial intermediate fluid temperature, through primary means for transferring heat between the hot flue gas and the initial intermediate fluid to create a hot intermediate fluid;
c) transferring heat from the hot intermediate fluid to either the fuel, the oxidant, or both, by flowing the hot intermediate fluid through one or more oxidant-fuel burners which create the main flow of hot flue gas, the oxidant-fuel burners having a fuel path for a fuel, an oxidant path for an oxidant, and a hot intermediate fluid path, wherein the hot intermediate fluid exchanges heat with either the oxidant, the fuel, or both the oxidant and the fuel, to create a cooled intermediate fluid.
It must be understood from the description herein that these methods are not strictly limited to embodiments wherein the fuel and oxidant are heat exchanged with the intermediate fluid at the same temperature of the intermediate fluid. In some embodiments, it is preferred to contact the hot intermediate fluid first with the oxidant, creating an intermediate fluid having a lower temperature, and subsequently exchanging heat of this lower temperature intermediate fluid with the fuel. Also, as stated previously, in certain embodiments, it is contemplated that the hot intermediate fluid could be mixed with the oxidant, the fuel or both.
Another aspect of the invention pertains to furnaces fired form the side. This aspect of the invention is a method of recovering heat in such a furnace that uses multiple oxidant-fuel burners, the method comprising:
a) creating the main flow of hot flue gas by burning a fuel with an oxidant in a plurality of side-mounted burners, a first portion of the burners mounted on a first side of a furnace, and a second portion of the burners mounted on an opposite side of the furnace;
b) flowing the hot flue gas through a stack at a first temperature (preferably at a temperature ranging from about 1000° C. to about 1700° C.);
c) flowing an initial intermediate fluid having an initial intermediate fluid temperature (preferably air at ambient temperature, about 25° C.), through a primary means for transferring heat (preferably a radiative metallic recuperator) to preheat the initial intermediate fluid (preferably to a temperature ranging from about 500 to about 900° C.) thus creating a hot intermediate fluid;
d) splitting the hot intermediate fluid flow into two streams, a first stream flowing to the first side of the furnace and a second stream flowing to the opposite side of the furnace, wherein on each of said first and opposite sides of the furnace are positions a plurality of oxidant preheaters and a plurality of fuel preheaters, and a plurality of burners, (preferably the number of oxidant preheaters is less than the number of burners and the number of fuel preheaters is less than the number of burners, (preferably the burners are grouped in pairs in order to reduce the number of oxidant and fuel preheaters);
e) flowing each of the first and second flows of hot intermediate fluid through one or more oxidant preheaters (preferably metallic or ceramic) in series, thus creating first and second flows of cooled intermediate fluid and a plurality of heated oxidant streams (the heated oxidant preferably having a temperature ranging from about 400 to about 800° C.);
f) flowing the cooled intermediate fluid through the fuel preheaters also installed in series, thereby creating a cold intermediate fluid and a plurality of heated fuel streams (preferably heating the fuel to a temperature ranging from about 200 to about 300° C.); and
g) splitting the heated oxidant and heated fuel streams to amount of streams equal to the number of burners to combust the fuel in the furnace, thus creating the main flow of hot flue gas.
Yet another aspect of the invention pertains to furnaces fired from one end. This aspect of the invention is a method of recovering useful heat in such a furnace, the method comprising the steps of:
a) combusting a fuel in a primary oxidant-fuel burner positioned at an end of the end-fired furnace, the primary burner supplying the main part of the energy to a load and creating the main flow of hot flue gas, and one or more additional conventional oxidant-fuel burners positioned generally opposite of the primary burner, for better coverage of a firing zone in the end-fired furnace;
b) flowing the hot flue gas through a stack at a first temperature (preferably at a temperature ranging from about 1000°C. to about 1700°C.);
c) flowing an initial intermediate fluid having an initial intermediate fluid temperature (preferably air at ambient temperature, about 25°C.), through a primary means for transferring heat (preferably a radiative metallic recuperator) to preheat the initial intermediate fluid (preferably to a temperature ranging from about 500 to about 900° C.) thus creating a hot intermediate fluid;
d) flowing the hot intermediate fluid to an oxidant preheater, thus producing a first cooled intermediate fluid and preheated oxidant;
e) flowing the cooled intermediate fluid to a fuel preheater, thus producing a second cooled intermediate fluid and heated fuel, the second cooled intermediate fluid having a temperature lower than the first cooled intermediate fluid, (preferably flowing the second cooled intermediate fluid to the stack at a temperature of about 300° C.); and
f) flowing the heated oxidant and heated fuel streams to the primary oxidant-fuel bumer to create the main flow of the hot flue gas leaving the furnace, the conventional burners also contributing to the hot flue gas.
Yet another aspect of the invention is also related to heat recovery in furnaces fired from one end, this aspect being a method similar to the first method of recovering heat from such a furnace, but differing in that this furnace has a plurality of primary burners (typically two) and the hot intermediate fluid is split into more than one stream after leaving the primary means for transferring heat, and transported to multiple oxidant preheaters and then multiple fuel preheaters.
Further advantages and aspects of the invention will become apparent by reviewing the following description and claims.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic process flow diagram representing method and apparatus of the invention;
FIG. 2 illustrates one preferred burner useful in accordance with the invention;
FIGS. 3 a and 3 b , respectively are schematic process flow diagrams of parallel and series heat exchange between a hot intermediate fluid and an oxidant and a fuel;
FIG. 4 illustrates one preferred burner useful in accordance with the invention;
FIG. 5 is a schematic process flow diagram of method and apparatus of the invention wherein two regenerative heat exchangers are employed;
FIG. 6 is a schematic process flow diagram of an integrated first wall/burner/heat exchanger useful in the invention;
FIG. 7 is a plan view of a typical furnace used in the glass production industry;
FIG. 8 is a schematic process flow diagram of heat exchanger means for exchanging heat between a cold intermediate fluid and hot flue gases used in the invention;
FIG. 9 is a schematic process flow diagram of a manifold useful in the invention for heating hot air, when used as an intermediate fluid, to a series of burners;
FIG. 10 is a schematic process flow diagram representing a method of using the apparatus of the invention for an example applied to a side fired type of glass furnace;
FIG. 11 is a schematic process flow diagram of an end-fired type glass furnace, wherein a single preheated oxy-fuel burner is employed; and
FIG. 12 is a schematic process flow diagram of an end-fired type of glass furnace, wherein two preheated oxy-fuel burners are employed.
DESCRIPTION OF PREFERRED EMBODIMENTS
The apparatus of the invention includes at least the following three components. The first component is primary heat transfer means located in the furnace flue stack or at least in contact with the flue gases. In typical commercial furnaces, the operating flue gases are typically and preferably hot, having a temperature ranging from about 1000° to about 17000 °C. In some processes such as found in the glass industry, the hot flue gases frequently carry particulates, or toxic species such as SO 2 , NOx, CO, and unburned hydrocarbons. The flue gas may also comprise corrosive components such as NaOH, sulfates, borates and the like in volatilized form.
The primary heat transfer means must be able to withstand temperatures in the above range. Preferably, refractory alloys, such as Inconel 600, Hasteloy, and the like, or ceramic materials are exemplary. Other suitable materials for the primary heat transfer means include composites of metals and ceramic materials such as ceramic coated metals.
As previously discussed, the primary heat transfer means employs an intermediate fluid to transfer some heat from the flue gases either to the oxidant, the fuel or both. The intermediate fluid is preferably clean, non-toxic, and non-combustible. Further, the intermediate fluid must be capable of being heated in the heat transfer means by the hot flue gases up to about 800°-1600° C. Preferred fluids include gases such as air, nitrogen, carbon dioxide, water vapor, and the like. Other preferred fluids include liquids, such as water, glycols, and the like, including mixtures of same. Air is the particularly preferred intermediate fluid for use in the present invention.
The second component of the apparatus of the present invention is transport means which transports the hot intermediate fluid to the vicinity of the fuel burners to exchange heat with the fuel, the oxidant, or both. Thus the hot flue gases preferably do not contact the oxidant or the fuel used to fire the furnace burners. This is particularly advantageous since particulates, corrosive gases, and volatile components commonly found in flue gases will not contaminate the oxidant, the fuel or the burners themselves and will not contaminate the transport means.
The heat transport means is typically and preferably a carbon steel pipe, possibly internally lined with refractory material. Other, more exotic metal materials may be used which may not have to be internally lined with refractory, such as Inconel 600, Hasteloy, and stainless steel 310, although their use is not preferred as much as carbon steel pipe possibly internally lined with refractory due to the expense of the exotic materials. The outer surface of the heat transport means is insulated to minimize heat losses from the transport means, and maintain the intermediate fluid at its initial high temperature, or substantially close thereto.
The third feature of the apparatus and method of the invention are the oxidant-fuel burners in combination with preheater means. The burner provides means of ejecting the fuel (preheated or not and the oxidant (preheated or not) into the furnace, in such manner that a flame is formed in the furnace and provides heat to the furnace load. The preheaters of course function to preheat the oxidant and/or the fuel which is sent to the burner. This is accomplished either with an integrated heat exchanger in the burner, such that the hot intermediate fluid transfers heat through a partition or other means inside the burner with either the fuel or the oxidant or both. Alternatively, the burner preheaters can be of the type wherein a bed of ceramic balls or bricks is preheated with the hot intermediate fluid, and then the oxidant or fuel caused to flow therethrough to preheat the oxidant or fuel prior to its entering the burner. A second bed of ceramic balls or bricks can be provided for the oxidant or the fuel when a continuous flow of oxidant or fuel is required at the burner for a continuous operation. The burner preheaters can be either in parallel or in series. In series embodiments, it is preferred to preheat the oxygen or oxidant with the hotter part of the intermediate fluid to prevent any fuel cracking problems that may occur at high temperatures. Preferred configurations are those where both the fuel and the oxidant are preheated with heat exchangers that are integrated in the burner, and where the fuel is preheated with a preheater integrated in the burner and the oxidant is preheated with a bed of ceramic balls or bricks.
In order that the burners may use the hot oxidant with the fuel without serious safety problems, the difficulties mainly lay in handling hot oxygen. Therefore, the parts of the burners used in the apparatus and process of the invention in contact with hot oxygen are preferably made of material compatible with hot oxygen or other oxidant. These compatible materials are preferably refractory oxides such as silica, alumina, alumina-zirconia-silica, zirconia and the like. Alternatively, certain metallic alloys that do not combust in hot oxygen use may be used. Coating metallic materials with ceramic materials on the surface exposed to hot oxygen can also be employed for the construction of the oxident-fuel burners.
In preferred embodiments of the invention the burner may form a part of the furnace wall, or the burner may be a separate burner block outside of the furnace wall.
The various burner embodiments and other aspects of the invention will be understood further with reference to the drawing figures.
FIG. 1 is a schematic process flow diagram illustrating the three main components of the apparatus of the invention. Thus, FIG. 1 illustrates a primary heat transfer means 2 , a transport means 4 which transports the intermediate fluid from primary heat transfer means 2 to a series of burners 6 . At primary heat transfer means 2 , which is preferably located in the flue stack of the furnace in question, hot flue gases 8 are fed through exchanger 2 preferably in a co-current fashion to a cool stream of intermediate fluid 10 having an initial temperature. Counter-current or cross-flow heat exchange modes are also possible for primary heat transfer means 2 . Stream 10 of intermediate fluid exchanges heat with the flue gas in primary heat transfer means 2 . Intermediate fluid exits primary heat transfer means 2 as hot intermediate fluid 12 . Hot intermediate fluid 12 is then transported by transport means 4 to burner preheater 20 , wherein cool fuel 14 and cool oxidant 16 enter the preheater. Preferably there are separate preheaters 20 a and 20 b as further denoted herein. Also illustrated in FIG. 1 is the burner itself 6 , and furnace wall 18 .
FIG. 2 illustrates one preferred burner usefull in accordance with the invention, wherein a fuel gas inlet is provided where cool fuel gas 14 enters the burner, and an oxidant inlet is provided where cool oxidant 16 enters the burner. Hot intermediate fluid 12 exchanges heat with fuel gas 14 in a preheater integral to the burner, while the hot intermediate fluid also exchanges heat with the cold oxidant stream 16 in a preheater integral to the burner. Warm fuel and oxidant are separately transported to the burner outlet, and ejected in the furnace through a burner block 6 ′, the burner block 6 ′ being positioned in a furnace wall 18 .
FIG. 3 a illustrates an embodiment wherein the burner preheaters 20 a and 20 b are arranged in parallel fashion with respect to the flow of hot intermediate fluid 12 , cool fuel 14 and cool oxidant 16 . Preheater 20 a creates a warm fuel stream 14 ′ and a warm intermediate stream 10 a. Similarly, burner preheater 20 b creates a warm oxidant stream 16 ′ and a cool intermediate stream 10 b.
FIG. 3 b represents a schematic process flow diagram of two burner preheaters 20 a and 20 b arranged in serial flow with respect to the flow of hot intermediate fluid 12 . Thus hot intermediate fluid 12 enters burner preheater 20 a and exchanges heat first with a cold oxidant stream 16 and produces a warm oxidant stream 16 ′. After exchanging heat with the oxidant, a cooler intermediate fluid stream 12 ′ flows through transport means 4 into second burner preheater 20 b so that the hot intermediate fluid exchanges heat with a cool fuel stream 14 to create a warm fuel stream 14 ′. Warm intermediate fluid 10 is then returned to the flue gas exchanger previously described.
FIG. 4 represents a burner useful for the invention where hot oxidant 16 ′ and hot fuel 14 ′ are separately injected in the furnace through oxidant injectors 7 and fuel injectors 8 located in furnace wall 18 . Another burner useful in the invention is illustrated in published European patent application no. 0 754,914, published on Jan. 22, 1997.
FIG. 5 represents a schematic process flow diagram of burner 6 and dual preheaters 20 a and 20 b which may be used in the following manner. Cool oxidant 16 enters either preheater 20 a or 20 b alternatively, depending on the positions of the flow control devices 30 a-h which preferably operate either fully opened or fully closed. For example, a stream of cool oxidant 16 may be allowed to enter bed 20 a which is filled with a plurality of ceramic balls 24 , if a flow control device fib 30 e is closed and flow control device 30 f is opened, as well as flow control devices 30 a , 30 b , and 30 d being closed and flow control devices 30 g , 30 c and 30 h being opened. In this case, a warm oxidant 16 ′ will be allowed to enter burner 6 . Alternatively, flow control device 30 f may be closed, flow control device 30 e opened, as well as flow control devices 30 a , 30 b , and 30 d being opened and flow control devices 30 c , 30 g , and 30 h being closed, thus allowing cool oxidant stream 16 to enter bed 20 b , thus creating a warm oxidant stream 16 ′ which is allowed to enter burner 6 . Of course, the same arrangement may be envisioned with cool fuel stream 14 , with the provision that the intermediate fluid is preferably an inert fluid like gaseous nitrogen. In this case the inert intermediate fluid would preferably be recycled in order to reduce the operating costs. Another inert intermediate fluid could be produced by consuming the oxygen in the intermediate fluid by combusting the O2 with methane or some other fuel. The result would be a host combustion products which would be further heated in the primary heat transfer means, and used as the intermediate heat transfer fluid. Using the apparatus illustrated in FIG. 5, bed 20 a may be operating to preheat an oxidant stream, while bed 20 b is being regenerated using a hot intermediate fluid stream 12 . Control devices may be valves or fluidic flow controllers.
FIG. 6 illustrates an embodiment where the burner and burner preheater means actually form a portion of the furnace wall. Thus, furnace wall 18 is shown allowing a cool stream of fuel 14 to pass therethrough, first contacting co-currently with a hot intermediate fluid stream 12 . Also, a cool oxidant stream 16 exchanges heat countercurrently with hot intermediate fluid stream 12 to form a warm oxidant stream 16 ′.
EXAMPLES
The following examples are merely intended to illustrate, and not limit, the invention.
Example 1
An apparatus of the invention is proposed to recover some of the waste heat from the flue gas of a furnace used in the glass industry. The furnace pull rate is assumed equal to 250 metric tons per day of soda-lime glass. Cullet (55% in weight) and batch mixture (45% in weight) are loaded at ambient temperature into the furnace. The heat of elaboration for this glass was 575 kWh per metric tons, accounting for the energy required to vaporize the water contained in the batch, the enthalpy of the chemical reactions in the batch, and the enthalpy of the molten glass at 1400° C. FIG. 7 is illustrative of the furnace, wherein hot intermediate fluid 12 is transported to each burner 6 a , 6 b , 6 c , etc. (only three burners illustrated). Fuel 14 (here natural gas) and oxidant 16 are preheated in each burner 6 as explained in the following. Hot flue gas 8 were used to warm up stream of intermediate fluid (air) 10 in primary heat transfer means 2 (FIG. 8 ). The hot air stream 12 was split at the furnace to feed a set of burners on one side of the furnace and a set of burners on the other side of the furnace (again, for simplicity, only three burners are illustrated in FIG. 7 ). FIG. 9 illustrates in section a portion of transport means 4 . In this embodiment, transport means 4 is a carbon steel pipe 26 lined with refractory material 28 , and covered with insulating material 27 to reduce the heat losses while transporting the hot intermediate fluid 12 .
The molar composition of the oxidant supplied to the burner is a product of a vacuum swing adsorption oxygen plant: 90% O2, 5% N2 and 5% Argon. The fuel is natural gas with a heat content of 10.55 kWh/Nm3. No electrical boosting is used in the furnace. The batch and cullet material release 69.6 Nm3 of a gas mixture composed of 59% CO2 and 41% water per metric ton of molten glass due to the humidity of the material and the chemical decomposition of the batch in the furnace. The total losses through walls, crown and ports equal 3300 kW.
The flue gas temperature is assumed equal to 1420° C. for all cases studied. It is also assumed that 5% of the molecular oxygen required to completely burn the fuel comes from air infiltration, and that the flue gas contains 2% of oxygen measured on a dry basis.
A baseline calculation was conducted assuming that both the oxidant and natural gas are supplied to the burners at room temperature (25° C.). The corresponding fuel energy required was 10,180 kW. The corresponding pure oxygen consumption was 83.7 metric tons per day.
The three following examples illustrate the fuel and oxidant savings that can be expected from an apparatus of the invention for the previous furnace configuration, depending on the heat exchangers, fluid preheaters and temperature levels.
Example 2
In the first case, the energy of the flue gas is partially recovered with some ceramic heat exchanger medium functioning as the primary heat transfer means that is used to preheat 3150 Nm3 of air as the intermediate cold fluid from 25° C. to 1100° C. The flue gas temperature at the outlet of be the primary heat transfer means is equal to 850° C. The hot intermediate fluid is transported through highly insulated pipes to the burners, for which it is assumed that the heat losses can be neglected. The hot intermediate fluid flows through pairs of high temperature heat exchangers (preheaters) installed in series. There are as many pairs of heat exchangers as burners installed in the furnace. For each burner, first, the oxygen is preheated to 1000° C. then the natural gas to 250° C. The intermediate fluid leaves the second heat exchanger at 210° C. The fuel requirement to produce the 250 metric tons per day of glass drops to 9,080 kW, which corresponds to fuel savings of 10.8% and the equivalent reduction of oxygen consumption.
Example 3
In the second case, 3150 Nm3 of air as the intermediate fluid is only preheated to 700° C. by some metallic heat exchanger medium functioning as the primary heat transfer means that imposes a lower limit of the temperature due to present state-of-the-art The flue gas leaves the heat exchanger medium at 1040° C. Heat losses in the means for transporting the hot intermediate fluid are also neglected for this example. Again, for each burner installed in the furnace, a pair of heat exchangers (preheaters) is installed in a series configuration to preheat the oxidant and the natural gas fuel. By cooling down the intermediate fluid to 300° C., the oxygen can be preheated to 600° C and the natural gas to 260° C. The fuel requirement is down to 9,467 kW, which corresponds to fuel and oxygen savings of 7.0%.
Example 4
This example is similar to Example 3 but the heat exchangers (preheaters) at the burners are placed in parallel. The intermediate fluid, 4200 Nm3, is preheated to about 700° C., transported to the burners without any significant heat loss, then the flow is split at each burner. Both the oxidant and the natural gas are preheated to 600° C., while the intermediate fluid is cooled down 280° C. The fuel requirement is now 9,182 kW, which translates in a 9.8% fuel and oxidant consumption savings.
Methods of using the inventive apparatus of the invention are described in the following examples that discuss possible furnace configurations.
Example 5
The first configuration can be used in a side fired furnace that uses for example twelve oxidant-fuel burners (FIG. 10 ). This firing configuration is the most common for oxidant-fuel fired furnaces in the glass industry. In this example, numerical values are given for illustration purposes only; different temperature levels can be used in the method of use of the apparatus of the invention. The flue gas 8 leaves the furnace through the stack 45 at about 1420° C. The cold intermediate fluid, air 10 , is vented by the circulation fan 32 through a radiative metallic recuperator 33 and preheated to about 700° C. The colder flue gas 22 can be thereafter treated at a lower temperature of about 1000° C. The hot intermediate fluid flow rate is split to each side of furnace in streams 12 a and 12 b . In this particular embodiment, the burners on each side of the furnace are grouped by pairs in order to reduce the number of oxidant and fuel preheaters. Other groups of burners can be formed with the burners located on each side of the furnace. In the present arrangement, for 6 burners ( 43 ) on each side there are only three oxygen preheaters ( 35 ) and three natural gas preheaters ( 36 ). The hot intermediate fluid 12 a flows through the three oxidant preheaters (metallic or ceramic) in series before the colder intermediate fluid 37 flows through the three natural gas preheaters also installed in series. The cold oxidant 16 and cold fuel 14 are heated respectively to about 600° C. and about 260° C. The hot oxidant and hot fuel 16 ′ and 14 ′ are split between the two burners 43 a and 43 b and are burned in the furnace which created in part the flue gas 8 at about 1420° C. The cold intermediate fluid 38 leaves the sixth heat exchanger and is vented to a stack at about 300° C.
Example 6
The second configuration (FIG. 11) can be used in a end-fired furnace with for example a unique large oxy-burner 43 that supplies the main part of the energy and some additional conventional oxy-fuel burners 47 a and 47 b for better coverage of the firing zone. Again, in this example, numerical values are given for illustration purposes only; different temperature levels can be used in the method of use of the apparatus of the invention. This configuration minimizes piping of the hot fluids: intermediate fluid, oxygen and fuel. The cold intermediate fluid, air 31 , goes through the circulation fan 32 before being preheated in the radiation metallic (for example) recuperator 33 up to about 700° C. by the combustion gas 44 leaving the furnace by the stack 45 at about 1420° C. The cooled furnace exhaust 46 can be thereafter treated or vented. The hot intermediate fluid 34 then preheat the cold oxygen 39 and the cold natural gas 40 by flowing through the two heat exchangers in series 35 and 36 (respectively). The cold intermediate fluid 38 flows to a stack at about 300° C. The hot gases, oxygen 41 at about 600° C. and natural gas 42 at about 260° C. are burned in the burner 43 to create the flue gas leaving the furnace 44 (the burners 47 a and 47 b also contribute the flue gas) at about 1420° C.
Example 7
The third configuration (FIG. 12) can be used in an end-fired furnace with only two large oxy-gas burners. This solutions limits the piping of the hot fluids: intermediate fluid, oxygen and natural gas. Again, in this example, numerical values are given for illustration purposes only; different temperature levels can be used in the method of use of the apparatus of the invention. The cold intermediate fluid, air 31 , is vented through the circulation fan 32 before being preheated by the flue gas 44 leaving the furnace at about 1420° C. in the metallic radiation recuperator 33 . The colder exhaust 46 goes then to the flue gas treatment or is vented through the stack at about 1000° C. The hot intermediate fluid is split for each side of the furnace into streams 34 a and 34 b at about 700° C. The hot stream 34 a flows through the heat exchangers in series 35 and 36 to preheat first the cold oxygen 39 and then the cold natural gas 40 . The cold intermediate fluid 38 is then vented through at about 300° C. The hot oxygen 41 at about 600° C. and the hot natural gas 42 at about 260° C. are burned in the burner 43 a to create the flue gas 44 . The other hot fluid burner 43 b and the firing burners 47 a and 47 b contribute also to the flue gas 44 that leaves the furnace through the stack 45 .
While reference has been made to specific embodiments, these are only to be illustrative and one of ordinary skill in the art may alter such embodiments without departing from the scope of the appended claims. | 4y
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is entitled to the benefit of British Patent Application No. GB 0813482.7, filed on Jul. 24, 2008.
FIELD OF THE INVENTION
[0002] The present invention relates to a gas turbine engine nacelle and in particular to a turbofan gas turbine engine nacelle.
BACKGROUND OF THE INVENTION
[0003] A turbofan gas turbine engine nacelle intake is required to supply the fan of the turbofan gas turbine engine with favourably conditioned air during all operational conditions of the turbofan gas turbine engine, irrespective of the aircraft environment and aircraft attitude, whether the aircraft is in flight or on the ground. The nacelle intake may also be required to absorb noise generated by the gas turbine engine.
[0004] Prior art nacelle intakes are designed to minimise the pressure loss of the intake at the maximum incidence the aircraft experiences in flight and at the maximum crosswind conditions on the ground. For example, good pressure recovery at high incidence can be achieved by attempting to ensure that the air flow remains attached to the bottom lip of the nacelle intake by drooping down the nacelle highlight and throat relative to the axis of the fan of the turbofan gas turbine engine.
[0005] FIG. 1 is a partially cut away view of a turbofan gas turbine engine having, in axial flow series, an intake 12 , a fan section 14 , a compressor section 16 , a combustion section 18 , a turbine section 20 and an exhaust 22 . The fan section 14 comprises a fan disc 24 carrying a plurality of circumferentially spaced radially extending fan blades 26 . The fan disc 24 and fan blades 26 are surrounded by a fan casing 28 . The fan casing 28 is mounted from the core casing 30 by a plurality of radially extending fan outlet guide vanes 32 . The fan section 14 is driven by a turbine in the turbine section 20 via a shaft (not shown). The compressor section 16 is driven by a turbine in the turbine section 20 by a shaft (not shown). The whole of the turbofan gas turbine engine 10 is placed within a nacelle 34 .
[0006] FIGS. 2 and 3 are respectively enlarged vertical and horizontal longitudinal cross-sections, containing the engine axis X, through the intake of the turbofan gas turbine engine nacelle shown in FIG. 1 . The nacelle 34 has an intake 12 at its upstream end and an exhaust 25 at its downstream end. The nacelle 34 intake 12 comprises, in flow series, a flared intake lip 36 , an intake throat 38 and a diffuser 40 upstream of the fan section 14 of the turbofan gas turbine engine 10 . The intake lip 36 forms a contraction for the supply of air to the intake throat 38 . The diffuser 40 is arranged to diffuse the air from the intake throat 38 to the fan section 14 .
[0007] The intake lip has an inner surface 36 A and an outer surface 36 B. The highlight H is a closed loop running around the intake lip, and defines the boundary between the lip inner and outer surfaces. In FIG. 2 the highlight H is viewed edge on and is indicated by a solid line. In FIG. 3 , the part of the highlight H below the plane of the drawing is indicated by a solid line, and the part above the plane of the drawing is indicated by a dashed line.
[0008] Generally, the highlight H lies in a highlight surface which is either planar or is curved in only one principal direction. On longitudinal sections through the engine containing the engine axis, the lip inner and outer surfaces are tangency matched at the highlight. Indeed, the lip inner and outer surfaces may be tangential to the highlight surface at the highlight. However, although the curvatures of the inner surface and outer surface are generally at a maximum at the highlight on a longitudinal section, these curvatures may not be the same maximum values. Thus it is typical for the lip to have a discontinuity in curvature across the highlight.
[0009] Travelling downstream along the inner surface 36 A on a longitudinal section, the end of the inner surface 36 A is reached when the tangent to the inner surface becomes 90° relative to the tangent to the inner surface on the same section at the highlight. Generally, on such a section, the curvature of the inner surface 36 A decreases continuously in the direction from highlight to the downstream end. The position of the intake throat 38 can be taken to be the downstream end of the inner surface 36 A.
[0010] A problem with nacelle intakes is that the flow path in the nacelle immediately upstream of the fan may not be symmetric. This can result in an asymmetric flow of air to the fan causing it to operate away from its optimum operating point and hence there is a loss of efficiency. Flow asymmetries may be cause, for example, by crosswinds.
[0011] Nacelle intakes may also not be optimised with respect to noise attenuation and other operational considerations.
SUMMARY OF THE INVENTION
[0012] Accordingly, a first aspect of the present invention provides a method of designing a nacelle for a gas turbine engine including the steps of: defining an initial geometry for a nacelle, the initial geometry providing an intake at the upstream end of the nacelle and an exhaust at the downstream end of the nacelle, wherein the intake has, in flow series, an intake lip and a diffuser, the intake lip having a highlight defining a boundary between the inner and outer surfaces of the intake lip, and on all longitudinal sections through the nacelle that contain the longitudinal axis of the nacelle (i) said inner and outer surfaces having their tangents coincident at the highlight, and (ii) said inner and outer surfaces having their maximum curvatures at the highlight; pivoting, at each of one or more positions on the highlight and in the plane of the respective longitudinal section, the upstream portion of the section of intake lip lying in the respective longitudinal section about the highlight; and adjusting surfaces of the intake neighbouring the pivoted upstream portion to smoothly blend the surfaces of the pivoted upstream portion to unadjusted surfaces of the intake further removed from the pivoted upstream portion to obtain an altered geometry for the nacelle. Typically, the defining, pivoting and obtaining steps are performed on a computer system.
[0013] This aspect of the invention allows a designer to exert great control over intake lip geometry, so that specific issues can be addressed, such as noise reduction, reduction in flow asymmetries etc.
[0014] The positions at which the front portions of the intake lip sections are pivoted are typically the crown, keel and sideline midpoint positions. However, the method can be applied to pivot upstream portions at any circumferential position on the highlight.
[0015] Typically, the highlight lies in a highlight surface which is either planar or is curved in only one principal direction, for example in the manner of a cylindrical paraboloid, although more complex shapes are possible. Indeed, when the initial nacelle geometry has such a highlight surface, on all longitudinal sections of that initial geometry, the inner and outer surfaces of the intake lip may be tangential to the highlight surface at the highlight. Typically, in this case, the pivoting step then results in the or each pivoted upstream portion crossing a tangent to the highlight surface at the position of that pivoted upstream portion.
[0016] Preferably, in the pivoting step, the or each front portion is pivoted by at most 5°. However, significant aerodynamic changes can be obtained with smaller rotations. Therefore, preferably, in the pivoting step, the or each front portion is pivoted by at least 0.1° or 0.25°. Typically, in the pivoting step, the or each front portion is pivoted by an angle in the range from 1° to 2.5°.
[0017] A further aspect of the invention provides a method of producing a nacelle for a gas turbine engine, including the steps of:
[0018] designing a nacelle according to the method of the previous aspect; and
[0019] manufacturing a nacelle having the altered geometry.
[0020] Another aspect of the invention provides a nacelle for a gas turbine engine, the nacelle having an intake at the upstream end of the nacelle and an exhaust at the downstream end of the nacelle, and the intake having, in flow series, an intake lip and a diffuser, wherein:
[0021] the intake lip has a highlight which is a closed loop defining a boundary between inner and outer surfaces of the intake lip, the highlight lying in a highlight surface which is either planar or is curved in only one principal direction (for example in the manner of a cylindrical paraboloid);
[0022] in an initial geometry, on all longitudinal sections through the nacelle that contain the longitudinal axis of the nacelle (i) said inner and outer surfaces have their tangents coincident at the highlight, and (ii) said inner and outer surfaces have their maximum curvatures at the highlight; and
[0023] in an altered geometry, at each of one or more positions on the highlight, and in the respective longitudinal section, a portion of the intake lip crosses a tangent to the highlight surface at that position and surfaces of the intake neighbouring that portion of the intake lip are adjusted to provide smoothly blended surfaces.
[0024] Thus, the nacelle can be one having an altered geometry designed by the method of the first aspect.
[0025] Preferably, on all longitudinal sections, the angle between the tangent to the inner and outer surfaces at the highlight and the tangent to the highlight surface is at most 5°, and more preferably at most 2.5°. Preferably, there is at least one longitudinal section for which the angle between the tangent to the inner and outer surfaces at the highlight and the tangent to the highlight surface is at least 0.1° and more preferably at least 0.25° or 1°.
[0026] A further aspect of the invention provides a gas turbine engine including a nacelle according to the previous aspect.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a partially cut away view of a known turbofan gas turbine engine;
[0028] FIG. 2 is an enlarged vertical longitudinal cross-section, containing the engine axis X, through the intake of the turbofan gas turbine engine nacelle shown in FIG. 1 ;
[0029] FIG. 3 is an enlarged horizontal longitudinal cross-section, containing the engine axis X, through the intake of the turbofan gas turbine engine nacelle shown in FIG. 1 ;
[0030] FIG. 4 shows the front portion of the section of intake lip at the keel position of a nacelle on a longitudinal cross-section containing the engine axis;
[0031] FIG. 5 shows the intake lip of FIG. 4 rotated about the highlight; and
[0032] FIG. 6 is a close-up view of the forwardmost part of the rotated intake lip of FIG. 5 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] FIG. 4 shows the front portion of the section of intake lip 50 at the keel position of a nacelle on a longitudinal cross-section containing the engine axis.
[0034] The intake lip 50 has inner 50 A and outer 50 B surfaces, which meet at a highlight H at the front of the nacelle. The highlight H lies in a curved highlight surface S which, in FIG. 4 , is viewed edge-on. In FIG. 4 , the highlight surface S is curved in the vertical direction of the page and is uncurved in the direction perpendicular to the page, i.e. it is curved in only one principle direction. However, in other examples, the highlight surface S may simply be planar.
[0035] The inner 50 A and outer 50 B surfaces are tangency matched at the highlight H, and indeed are tangential to the highlight surface S at the highlight H. The inner 50 A and outer 50 B surfaces also have their maximum curvatures at the highlight H. However, these curvatures are different for the inner 50 A and outer 50 B surfaces, whereby there is a discontinuity in curvature across the highlight.
[0036] The intake lip axis A lying in the plane of the drawing of FIG. 4 extends from the highlight H parallel to the engine axis, or to the intake droop axis in the case of a drooped intake.
[0037] The intake lip shown in FIG. 4 represents a geometry for the nacelle, resulting, for example, from an initial nacelle design procedure.
[0038] A next step in the design procedure is to pivot, in the plane of the respective longitudinal section, the front portion of the intake lip about the highlight H in a direction which rotates axis A either towards the engine axis (+θ, dot-dashed lines) or away from the engine axis (−θ, dotted lines), as shown in FIG. 5 , and in more detail in FIG. 6 , which is a close-up view of the forwardmost part of the rotated intake lip.
[0039] The tangent T to the highlight surface S at the highlight H is indicated with a dashed line in FIG. 6 . Of course, if the highlight surface S is planar, the tangent T to the highlight surface S will be coincident with that surface. Because the inner 50 A and outer 50 B surfaces of the intake lip 50 are tangential to the highlight surface S at the highlight H in the initial geometry of FIG. 4 , the +θ rotation has the effect of causing the inner surface 50 A to cross the tangent T inwards of axis A, whereas the −θ rotation has the effect of causing the outer surface 50 B to cross the tangent T outwards of axis A.
[0040] Having rotated the part of the front portion of the intake lip at the keel position, the next step in the design procedure is to adjust the surfaces of neighbouring parts of the intake to smoothly blend the surfaces of the rotated front keel part with the surfaces of unadjusted parts of the intake further removed from the rotated part. This blending can be performed by methods known to the skilled person.
[0041] If the intake lip is rotated at just one position, such as the keel section discussed above, the adjustment procedure effectively results in an altered nacelle geometry in which the angle of rotation of the intake lip reduces around the highlight from a maximum amount at that section down to zero at a circumferential distance from the section, those parts of the intake lip having some rotation defining a transitional sector.
[0042] Thus, for example, lip rotation can be by an appropriate angle ±θ at a specific circumferential location to locally address a specific aerodynamic performance issue (e.g. high incidence at the keel, or crosswind at the sidelines), with θ smoothly transitioning to zero away from that circumferential location. The extent of the transition can be varied and the variation of θ within the transitional sector can be linear or controlled by an appropriate non-linear expression as a function of circumferential location.
[0043] However, more complicated adjustments can be effected. For example, lip rotation can be by an appropriate angle ±θ at a specific circumferential location to locally address a specific aerodynamic performance issue, with θ smoothly transitioning to a different ±θ elsewhere on the intake, itself transitioning to another ±θ at yet another part of the intake and so on, such that the θ variation is determined by respective rotations on multiple control sections. The variation of θ within each transitional sector can be linear or controlled by an appropriate non-linear expression as a function of circumferential location.
[0044] The external frontal area of the nacelle may be altered as a result of the altered geometry.
[0045] In the case of a −θ rotation the pivoting results in a shift of the local throat forwards, whereas in the case of a +θ rotation the pivoting results in a shift of the local throat rearwards. In general, care should be taken to ensure that the throat area does not become too small as a result of rotations.
[0046] Typical rotation angles are between 1° and 2.5°. However, even small rotations, for example around 0.25° or even 0.1°, can have significant aerodynamic impacts. Some situations may call for rotation angles of up to about 5°.
[0047] Pivoting the intake lip at specific positions around the highlight allows intake lip profiles to be de-coupled and individually optimised to locally address specific aerodynamic performance issues. For example:
[0048] Higher angles of attack can be produced by rotating lip sections in the lower half of the intake towards the engine axis (+θ).
[0049] For a negatively scarfed intake, more aggressive diffusion can be generated at the keel without dropping the intake bottom line by rotating the keel intake lip towards the engine axis (+θ). The larger diffuser angles further rearward in the duct which can then be produced can provide benefits in terms of reduced diffuser length, increased nacelle ground clearance and reduced fan face pressure distortion. For a positively scarfed intake, less diffusion at the keel may be beneficial and can be generated by rotating the keel intake lip away from the engine axis (−θ).
[0050] Enhanced crosswind capabilities can be obtained by rotating the sideline lips towards the engine axis (+θ).
[0051] Elimination or reduction of shock buzz noise during ground static operation can be obtained by rotating the crown lip axis to better align the intake lip with the bulk flow. External drag benefits may also be produced due to resulting changes in the shape of the external nacelle top surface. The rotation at the crown can be towards (+θ) or away from (−θ) the engine axis, depending on local flow conditions.
[0052] More generally, locally pivoting the intake lip can also provide the following benefits:
[0053] Lip profiles, throat area and local throat positions can be redistributed without changing the highlight shape.
[0054] The greater control over lip geometry enables nacelle designs in which asymmetries in the flow entering the intake duct are minimised, resulting in noise benefits due to reduced flow asymmetry around the intake lip and/or benefits associated with reduced fan forcing or fan face pressure distribution further downstream.
[0055] Intake lip rotation can enhance the design of negatively scarfed intakes, such that duct flow asymmetry downstream of the lip is reduced while tolerance to off-design external flows is maintained.
[0056] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. For example, although the procedures of pivoting a part of the front of the intake lip and then adjusting neighbouring surfaces are described above in relation to a nacelle having a highlight surface which is a plane or is curved in only one principle direction and having inner and outer surfaces which are tangential to the highlight surface at the highlight, they may also be applied to nacelles having highlights which do not lie in such highlight surfaces, and/or having inner and outer surfaces which are not tangential to the highlight surface at the highlight. For example, a nacelle which has undergone the pivoting and adjusting procedures will have inner and outer surfaces which are not tangential to the highlight surface at the highlight. However, the procedures can nonetheless be reapplied to this nacelle. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention. | 4y
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FIELD OF THE INVENTION
The present invention pertains to a fluid mass flow controller, particularly adapted for controlling the flow of toxic or highly reactive gases used in the fabrication of semiconductor devices and the like and including a method of operation of the controller based on data which correlates controller operation with a fluid differential pressure across a flow restrictor part of the controller and the downstream fluid pressure viewed by the controller.
BACKGROUND
Some effort has been put forth to develop precision fluid mass flow controllers, particularly flow controllers for controlling the mass flow rates of fluids, such as toxic and highly reactive gases, of the type used in the fabrication of semiconductor devices, for example. In the field of semiconductor fabrication, various gases are used in etching and vapor deposition processes, which gases are toxic to humans and are also highly reactive when exposed to ambient atmospheric conditions, for example. Mass flow controllers have been developed which measure and control the flow rate of fluids of the above-mentioned type wherein the measurements are based on thermal properties of the fluids. Other fluid mass flow controllers have been developed which are based on measuring a pressure differential across a flow restrictor or orifice. The accuracy of prior art fluid mass flow controllers of the type in question here is inadequate for many applications of flow controllers.
Semiconductor fabrication processes may require the discharge of very precise quantities of fluids (primarily gases) into a process chamber. For example, flow rates ranging from as high as twenty liters per minute to as low as a few tenths of one cubic centimeter per minute (CCM) may be required. Moreover, the response time and stabilization rate of flow controllers used to control reactive gases in semiconductor fabrication may require that the controller be able to react to an “on” signal and be stable at the required fluid flow rate within 0.5 to 1.0 seconds. The process itself may last anywhere from a few seconds to several hours and the shutoff response time of the fluid flow controller is usually required to be less than one second. The ability for thermal based fluid mass flow controllers to react and stabilize at such rates is difficult to achieve.
Another problem associated with prior art fluid mass flow controllers of the general type discussed herein pertains to the requirements to calibrate the controllers for various process fluids. Prior art fluid mass flow controllers are typically calibrated using an inert or nontoxic calibration fluid which requires the development of conversion factors or conversion data sets. Since the use of toxic or highly reactive process fluids for calibrating each controller instrument is cost prohibitive and dangerous to operating personnel, prior art mass flow controllers are typically calibrated on an inert fluid, such as nitrogen or argon, or a fluid whose properties are similar to the properties of the process fluid to be controlled by the mass flow controller. This process of using calibration fluids and conversion factors introduces errors into the operation of the mass flow controllers, is time consuming and thus expensive. The inaccuracy of prior art mass flow controllers and the expense and time required to calibrate controllers during initial setup, as well as in replacement procedures, adds substantially to the cost of many manufacturing processes, including the fabrication of semiconductor devices, to the point that certain improvements in fluid mass flow controllers have been highly desired.
Accordingly, several desiderata have been identified for fluid mass flow controllers, particularly of the type used in manufacturing processes as described above. Such desiderata include controller accuracy within a few percent of controller setpoint (at least one percent is desired), operation at elevated or below “normal” temperatures and various positions or attitudes (i.e., right side up, sideways, or upside down), without loss of accuracy, such as experienced by thermal based mass flow controllers, accurate measurement and control over a wide range of flow rates, fast response time from turn-on to achieving stable flow conditions, economy of manufacture and uncomplicated modular mechanical structure to facilitate servicing the flow controller and to facilitate changing the flow controller out of the fluid flow distribution system for the manufacturing process. Other features desired in fluid mass flow controllers include no requirement to calibrate each complete controller instrument at the time of manufacture or recalibrate the instrument after servicing, the provision of a reliable easily interchanged flow restrictor or orifice part, ease of verification of the operability and accuracy of the flow controller after servicing or changeout of a flow restrictor, the ability to accurately control flow rates for a wide variety of toxic and/or reactive fluids, particularly the hundreds of fluids in gaseous form which are used in semiconductor fabrication processes, and ease of changing the controller working data for flow rates for different gases or fluids in liquid form. It is to these ends that the present invention has been developed.
SUMMARY OF THE INVENTION
The present invention provides an improved fluid mass flow controller and method of operation. In particular, an improved mass flow controller and method of operation are provided for use in connection with controlling the flow of gaseous fluids used in the manufacture of semiconductor devices and the like.
In accordance with one aspect of the present invention, a fluid mass flow controller is provided which utilizes measurements of differential pressure across a flow restrictor and the pressure downstream of the flow restrictor to provide a more accurate reading of the actual mass flow of a particular fluid at a particular temperature. Such measurements may be carried out using only two pressure sensors or transducers and over a wide range of temperatures of the fluid being measured.
The present invention further provides an improved fluid mass flow controller, particularly adapted for controlling the mass flow rate of toxic and reactive gases, including those used in the fabrication of semiconductor devices wherein the flow controller includes rapid response time to stabilize at a desired setpoint flow rate and is accurate within setpoint conditions to less than one percent error. The controller is also operable to measure mass flow rates over a wide range of such flow rates, on the order of a ratio of maximum to minimum flow rates as great as 100 to 1. The mass flow controller does not require calibration with a process fluid or with a calibration fluid and thus no conversion factors are required in the flow measurement process.
The present invention also provides an improved fluid mass flow controller which operates by measurement of fluid differential pressures across and the fluid pressure downstream of a flow restrictor and which utilizes data for the mass flow of selected fluids within a range of differential pressures and downstream pressures to which the controller will be exposed and in which the controller will be operated. The mass flow controller and flowmeter of the invention is also operable over a wide range of inlet pressures from above atmospheric pressures to vacuum conditions experienced with so-called safe delivery systems for toxic or reactive gases. Still further, the invention includes a fluid mass flow controller which is operably associated with a control system including a suitable processor circuit, such as a digital signal processor, a nonvolatile memory for storing the aforementioned data and which may receive additional sets of data when desired.
The present invention further provides a fluid mass flow control apparatus which is of mechanically uncomplicated construction, is modular in form and is particularly adapted for rapid changeout of a replaceable flow restrictor, one or more pressure transducers and a single flow control valve associated with the controller.
The present invention still further provides a flow restrictor for which data of flow versus differential pressure and downstream pressure are available as data sets for a multiplicity of fluids, particularly adapted for use with a pressure based fluid mass flow controller or flowmeter in accordance with the invention, but is adaptable for other applications and is adapted for use with toxic and reactive gases, in particular.
Still further, the present invention contemplates a method for measuring and/or controlling the mass flow rate of a fluid by measuring differential pressures across a flow restrictor and the fluid pressure downstream of the restrictor, and particularly, but not limited to operating conditions wherein the downstream pressure is below atmospheric pressure. The invention further contemplates a method of operation of a fluid mass flow controller which does not require calibration of the controller with calibration fluids but utilizes predetermined data sets for a flow restrictor part of the controller for various types of process fluids, including those which may be toxic or highly reactive.
The invention also contemplates a fluid mass flow controller including a microcontroller or processor device adapted to receive signals from two pressure sensors, a temperature sensor and command signal inputs while providing a suitable analog output signal for a control valve associated with the fluid mass flow controller. Still further, the microcontroller is operable to support RS485 communication and various network communications for receiving data from a remote site and for supporting and inputting data to a serial EEPROM. Accordingly, the invention contemplates a method of operation of a fluid mass flow controller wherein data sets characterizing a flow restrictor for different fluids may be obtained remotely via a network for rapid change in operation of the controller on various types of fluids.
Those skilled in the art will further appreciate the above-mentioned advantages and superior features of the invention together with other important aspects thereof upon reading the detailed description which follows in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a somewhat schematic view of the fluid mass flow controller of the present invention;
FIG. 2 is a longitudinal, generally central section view of the controller shown in FIG. 1 and showing some features of fluid flow circuitry normally associated therewith;
FIG. 3 is a detail section view of a flow restrictor used in the flow controller of FIGS. 1 and 2 and in accordance with the present invention;
FIG. 4 is a diagram showing the mass flow rate of a gaseous fluid as a function of differential pressure across a flow restrictor and the downstream pressure, all in relatively low pressure ranges of about zero torr to about 2,000 torr;
FIG. 5 is a longitudinal section view of another embodiment of the flow restrictor and an associated support fitting in accordance with the invention;
FIG. 6 is a diagram similar to FIG. 4 showing the characteristics of another type of flow restrictor as a function of differential pressure across and pressure downstream of the flow restrictor; and
FIGS. 7A and 7B are flow charts of certain steps carried out in the operation of the fluid mass flow controller shown in FIGS. 1 and 2.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In the description which follows, like elements are marked through the specification and drawings with the same reference numerals, respectively. The drawings may not necessarily be to scale and certain features may be shown in generalized or schematic form in the interest of clarity and conciseness.
Referring to FIGS. 1 and 2, an improved fluid mass flow controller in accordance with the invention is illustrated and generally designated by the numeral 20 . The mass flow controller 20 includes a two-part modular body 22 comprising generally rectangular block shaped body parts 24 and 26 which may be suitably joined to each other by conventional mechanical fasteners 28 at cooperating planar faces 24 a and 26 a , respectively. The body parts 24 and 26 are provided with suitable fluid conductor connector portions 25 and 27 to provide for connecting the fluid mass flow controller to conduits for a system for supplying, in particular, toxic or reactive fluids in gaseous form for use in semiconductor fabrication, for example.
By way of example, as shown in FIG. 2, the mass flow controller 20 may be interposed in a fabrication system including a source pressure vessel 28 for pressure fluid such as tungsten hexafluoride, chlorine, or sulfur hexafluoride, for example. Source pressure vessel 28 is connected to the flow controller 20 via a suitable conduit 30 and a purge conduit 32 is also connected to conduit 30 and to a source of purge gas, not shown, for purging the flow controller to a suitable receiver or scrubber 34 , when needed. During operation of the flow controller 20 , however, a precise flow of fluid is controlled for entry into a semiconductor fabrication chamber or vessel 36 via conduit 33 . Chamber 36 is typically maintained at a substantially reduced pressure by way of one or more vacuum pumps 37 , for example. The system in which the flow controller 20 is interposed, as shown in FIG. 2, is shown by way of example in simplified form to illustrate one preferred application of the flow controller.
Referring primarily to FIG. 2, the body part 24 supports an electrically controlled flow control valve 40 which is removably mounted on a face 24 b of body part 24 by conventional mechanical fasteners, not shown. Valve 40 includes an electrically actuated closure member 41 operable to throttle flow of fluid from an internal passage 42 of body part 24 to a second internal passage 44 of body part 24 . Valve 40 also includes an actuator 43 for the closure member 41 . Actuator 43 is preferably of a type using a solenoid or piezoelectric material for rapid response and fineness of control of closure member 41 . A first pressure transducer 46 is also removably mounted on body part 24 and is in communication with a passage 47 in body part 24 which is in communication with passage 44 . A second pressure transducer 48 is removably mounted on body part 26 and is in communication with a passage 49 which opens into a longitudinal passage 50 in body part 26 , which passage is also connected to conduit 33 leading to the fabrication chamber 36 . Pressure transducers 46 and 48 may be of a type commercially available from Honeywell Data Instruments Division, for example. Control valve 40 and pressure transducers 46 and 48 may be disposed within a removable cover 51 , FIG. 1, for the flow controller 20 .
Referring also to FIG. 3, the body part 24 includes a cylindrical counterbore 54 formed therein and concentric with the passage 44 for receiving a flow restrictor 56 . Flow restrictor 56 is supported in a tubular sleeve 58 which may be mounted in a suitable tubular adapter 60 supported in the counterbore 54 between seal rings 62 . Accordingly, the flow restrictor 56 may be easily removed from the body 22 by separating the body parts 24 and 26 , removing the flow restrictor together with its support sleeve 58 and replacing the flow restrictor with a suitable replacement restrictor of the same flow characteristics or a selected other flow characteristic. The flow restrictor 56 preferably comprises a sintered metal cylindrical plug shaped member having a predetermined porosity for allowing fluid to flow therethrough by providing restriction to flow sufficient to create a differential pressure thereacross which may be sensed by the pressure transducers 46 and 48 . Flow restrictor 56 may, for example, be fabricated of stainless steel or nickel particles suitably compressed and sintered to provide the desired porosity and flow restriction characteristic. Flow restrictor 56 is advantageously disposed in flow controller 20 downstream of control valve 40 .
Referring again to FIG. 1, the flow controller 20 is adapted to be operated by a control circuit or system including a microcontroller characterized as a digital signal processor 70 which is operably connected to a non-volatile memory, such as an EEPROM 72 , a power supply 74 and a suitable valve driver circuit 76 . The microcontroller 70 is operably connected to the valve 40 for effecting movement of the closure member 41 by way of the driver 76 . The microcontroller 70 is also operably connected to the pressure transducers 46 and 48 and to a temperature sensor 78 which may be located to sense the temperature of fluid flowing through the controller 20 at a predetermined location. The microcontroller 70 is also operably connected to a suitable interface 80 for receiving command signals, data sets and programming changes from various sources.
The microcontroller 70 is preferably a TMS320 LF2407 fixed point microcontroller available from Texas Instruments Incorporated. The pressure sensors 46 and 48 operate in a plus/minus 0.5 volt range with fourteen to sixteen bit resolution as analog inputs to the microcontroller 70 which carries its own A/D and D/A converters. Other analog inputs will be for the temperature sensor 78 and a zero to five volt set point command signal input with twelve bit resolution. The microcontroller 70 also provides analog output signals for controlling operation of the valve 40 via the driver 76 . Communication with the microcontroller 70 may be via an RS485 4-wire communication link and/or a CAN (Controller Area Network). The microcontroller 70 is also capable of supporting a JTAG interface for emulation and debug and a powerup bootloader function for programming. The memory 72 is preferably a serial EEPROM of at least four thousand bytes.
The microcontroller 70 requires a closed loop control function to be executed at a rate of about one hundred times per second between the inputs for the pressure sensors 46 and 48 and the output signal for controlling the valve 40 . Communication through interface 80 is carried out while the control loop is functioning although new data transfer or transfer to the memory 72 may be supplied when control loop updates are not being maintained.
An important aspect of the present invention resides in the discovery that, in a normal operating range of the mass flow controller 20 , the fluid flow rate is a function not only of the differential pressure across the flow restrictor 56 but also the absolute downstream pressure corresponding substantially to the pressure in the fabrication chamber 36 . FIG. 4, for example, shows a typical characteristic of flow in standard cubic centimeters per minute (SCCM) as a function of the differential pressure (torr) across the flow restrictor 56 and also as a function of the downstream pressure (torr) in the passage 50 , conduit 33 and fabrication chamber 36 . The diagram of FIG. 4 indicates that the flow characteristics of a fluid flowing across a restrictor, in the pressure ranges indicated in the diagram, may be in accordance with a three-dimensional surface indicated by numeral 90 . The flow characteristic or surface 90 is for a particular temperature. In the diagram of FIG. 4, the mass flow characteristic 90 for the fluid tested was conducted at 25° C. As indicated in FIG. 4, measurements taken at lower temperatures would provide flow characteristics indicated by the surfaces 92 and 94 , for example. The flow characteristic indicated by surface 92 is for a temperature lower than the temperature for the flow characteristic indicated by surface 90 and the flow characteristic which is determined by the surface 94 is at a temperature lower than the measurements taken for developing the flow characteristic surface 92 .
It will also be noted from viewing FIG. 4 that a mass flow rate across a flow restrictor, particularly for the pressure ranges indicated in the diagram, varies with the downstream pressure. For example, if the downstream pressure is approximately 0.0 torr and the pressure differential across the flow restrictor is approximately 1575.0 torr, the flow rate for the particular restrictor tested is about 280 SCCM. However, if the downstream pressure is 760.0 torr (standard atmospheric pressure), the flow rate for the same pressure differential across the flow restrictor is approximately 500 SCCM. Accordingly, the behavior of fluids flowing across a flow restrictor, particularly in gaseous form, is dependent not only on temperature and differential pressure but also the pressure downstream of the flow restrictor.
The flow characteristics indicated in FIG. 4 at various temperatures, differential pressures across the flow restrictor and downstream pressures are for a sintered metal type flow restrictor, such as the flow restrictor 56 . Alternatively, viewing FIG. 6, a similar flow characteristic is indicated for a sharp edged circular orifice at 25° C. and is indicated by numeral 95 . The specific flow characteristics shown in FIGS. 4 and 6 are for nitrogen gas although other gases are indicated to behave in accordance with the general flow characteristics shown in FIGS. 4 and 6 for the types of flow restrictors described herein.
Accordingly, a flow characteristic in accordance with the diagrams of FIGS. 4 and 6 may be developed for particular types of flow restrictors used in connection with a mass flow controller, such as the controller 20 , and for various fluids in liquid and gaseous form, including the process gases or vapors used in semiconductor fabrication.
Data points representing the three-dimensional flow characteristics, such as the surfaces 90 , 92 and 94 in FIG. 4, may be developed in various ways and entered into the memory 72 of the flow controller 20 . The flow controller microcontroller 70 , when operated in a set point mode can be programmed to command operation of the valve 40 to adjust the flow through the flow controller 20 to approach the setpoint by sensing the pressure differential across the flow restrictor by the pressure transducers 46 and 48 to determine the actual flow rate, repeatedly, until the flow rate is essentially that programmed into the microcontroller 70 as the setpoint or pursuant to instructions input to the microcontroller. The data points representing the surfaces 90 , 92 94 for a particular gas may be obtained using conventional flow measuring equipment.
A rate of change mass flow measuring apparatus may also be used to obtain the data points. Moreover, such a flow measuring apparatus may be used to verify the operation of a flow controller, such as the flow controller 20 within its design specification, and such apparatus may also be used to verify whether or not a particular flow restrictor is within its design specification. Once a design specification has been established for a flow restrictor and a flow controller of the types described herein, the performance of each may be verified by a rate of change mass flow measuring apparatus or other mass flow measuring apparatus or devices and use of an inert gas so that toxic and highly reactive gases are not required to be used during verification tests on the complete flow controller or on a flow restrictor, respectively. For example, a selected number of data points may be verified at flow rates of 50, 100, 500 and 3,000 SCCM at 30 psig inlet pressure, with exhaust pressure being atmospheric, for a flow controller, such as the controller 20 , or for a flow restrictor, such as flow restrictor 56 . Data points representing the design specification of the flow controller 20 may also be entered into the memory 72 to verify the operability of the flow controller when tested with the aforementioned rate of change flow measuring apparatus. A suitable rate of change or so-called rate of rise mass flow measuring apparatus is commercially available.
Moreover, the fluid mass flow controller 20 may also be connected via its interface 80 with a network adapted to be connected to a source of data for any fluid which has been tested in conjunction with a controller of the same type as the flow controller 20 . In this way, any gas to be controlled by the flow controller 20 may have its flow characteristics entered into the memory 72 by merely querying a database stored in a suitable processor. For example, a vendor of the flow controller 20 may have selected data sets stored on a suitable processor and memory associated therewith for a wide variety of gases, each data set corresponding substantially to the type of data sets that would provide the flow characteristics shown in FIGS. 4 and 6 for any one type of flow restrictor, respectively. An authorized customer using a flow controller, such as the flow controller 20 , and desiring to begin using the controller with a particular gas would merely make an inquiry to the vendor source and download the needed data set directly to the microcontroller 70 and its memory 72 via a network such as the Internet, for example.
Operation of the microcontroller 70 is generally in accordance with the flow diagrams of FIGS. 7A and 7B and will now be described in further detail. The microcontroller or processor 70 is operable to execute closed loop control and communication functions. Closed loop control is preferably executed at a rate of 100 times per second and requires execution of lookup tables or polynomial calculations. All code may be written in “C”. The functions of the microcontroller or processor 70 are summarized in the flow diagram of FIG. 7 A. Step 100 in FIG. 7A indicates a 10 millisecond interrupt to drive the key functions of the processor 70 . In step 102 , the processor obtains 64 samples of downstream pressure XD 1 and averages the samples. In step 104 , the processor 70 obtains 64 samples of the upstream pressure XD 2 and averages the samples. Step 106 is an averaging of 32 samples of an analog output signal for control of the valve 40 identified by the software tag CV 1 SN. Step 108 indicates operation of the processor 70 in the signal mode to obtain 32 samples of a zero to five volt setpoint command signal input in step 110 , and a 32 sample zero to five volt analog output signal in step 112 . Step 114 indicates when analog inputs are shorted to ground. Step 116 indicates the processor obtaining 32 samples of the signal from temperature sensor 78 , indicated as TE 1 , and averaging such samples. Step 118 provides for converting the signal inputs to English units of pressure, flow and temperature. Step 120 in FIG. 7A is the execution of a calculation of flow routine using, for example, the surfaces 90 , 92 and 94 of FIG. 4 . New processor proceeds to the control mode at step 122 .
FIG. 7B illustrates how the calculation of flow routine is carried out using sets of so-called three dimensional maps, such as the surfaces 90 , 92 and 94 , for example, for respective operating temperatures and whereby the flow is calculated as a function of the variables of differential pressure across the flow restrictor 56 , the downstream pressure in the flow passage 50 and the temperature sensed by the sensor 78 . A set of flow runs over a range of downstream pressures and flow rates is obtained for the flow restrictor 56 . This data set is fitted to an array of three dimensional curves. The so-called map can be thought of as flow on the z axis mapped to differential pressure, XD 2 −XD 1 , on the x axis and discharge or downstream pressure, XD 1 on the y axis.
The best-fit process generates curves at various values of y. Typically curves of x versus z might be generated for XD 1 being equal to 1, 50, 100, 300, 500 and 700 torr, for example. Then the process is repeated at another operating temperature. The calibration data is then mapped from floating point numbers to the fixed point quantities that are used in the processor. These tables are download to the processor and are called during the flow calculations. The get calibration data of step 124 , FIG. 7B, is carried out by obtaining the calibration maps or surfaces at the nearest temperature above and below the temperature sensed by sensor 78 . At steps 126 and 128 , flow is calculated by interpolating the differential pressure XD 2 −XD 1 for two curves in the calibration data (CAL DATA). Flow at the current calibration temperature is calculated by interpolating between calibration flow data points. At steps 130 and 132 flow at the current CAL DATA temperature is calculated by interpolating between Flow( 0 ) and Flow(i) by the value of XD 1 and the y axis values for Flow( 0 ) and Flow( 1 ). Flow is calculated by interpolating between the Flow@Temp( 0 ) and Flow@Temp( 1 ) by the value of TE 1 and the temperatures for the two CAL DATA sets selected.
Referring briefly to FIG. 5, as previously mentioned the flow restrictor 56 may be adapted for operation in conjunction with other flow controllers and related devices. The flow restrictor 56 may, for example, be removably mounted in a conventional fitting, such as a face seal union fitting 110 . The fitting 110 includes a longitudinal through passage 112 which is counterbored at one end to provide a bore 114 for receiving the cylindrical plug flow restrictor 56 and its tubular support sleeve 58 . The sleeve 58 may be a light press fit in the bore 114 . By way of example, a flow restrictor for use in conjunction with the flow controller 20 may be characterized as a cylindrical plug having a diameter of approximately 0.18 inches and a length of approximately 0.18 inches and may be formed of porous sintered stainless steel, nickel or Hastelloy C-22. The solid steel sleeve 58 may be formed of 316L stainless steel. It is contemplated that the manufacturing tolerances of the flow restrictor 56 may be such as to require only verification of the performance characteristics of the restrictor by verifying the mass flow rates of, for example, 50, 100, 500 and 3,000 SCCM at a pressure upstream of the restrictor of 30 psig with exhaust to atmosphere.
Accordingly, no calibration or calibration conversion factors are necessary for the flow restrictor 56 or the flow controller 20 . When once placed in use, the flow controller 20 and/or the flow restrictor 56 may be verified as to its operability by flowing predetermined quantities of an inert gas through these devices using the aforementioned rate of change flow measuring apparatus or a similar apparatus to verify performance. The flow restrictor and/or the flow controller may then be placed in or returned to service with assurance that the respective devices will perform in accordance with a flow characteristic, such as that indicated in FIG. 4, for example.
The construction and operation of the mass flow controller 20 and the flow restrictor 56 , as well as the method of operation of the flow controller as set forth hereinabove, is believed to be readily understandable to those of ordinary skill in the art. Moreover, the flow controller 20 functions as a flowmeter and may be used as a flowmeter as well as for controlling fluid flow rate to a setpoint condition.
Although preferred embodiments of the invention have been described in detail herein, those skilled in the art will recognize that various substitutions and modifications may be made to the invention without departing from the scope and spirit of the appended claims. | 4y
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FIELD OF THE INVENTION
This invention relates to novel undoped and doped nanometer-scale metal oxide particles as well as a novel method for directly synthesizing doped and undoped nanometer-scale CeO 2 particles having a controlled particle size ranging from 3–100 nanometers.
BACKGROUND OF THE INVENTION
Cerium dioxide (CeO 2 ) based materials have been studied for use in various applications including 1) fast ion conductors; 2) oxygen storage capacitors; 3) catalysts; 4) UV blockers; and 5) polishing materials. Pure and doped CeO 2 exhibits the cubic fluorite structure, similar to ZrO 2 . Doping CeO 2 with lanthanide series elements (e.g. Gd 3+ ) results in the formation of oxygen vacancies ([Gd 3+ ]=2[Vo oo ]), and a high ionic conductivity, σ i . In particular, Ce 0.9 Sm 0.1 O 1.95 exhibits a σ 1 =0.025 (Ω*cm) −1 at 600° C., which is more than five times that of ZrO 2 based materials. As such Ce 0.9 Sm 0.1 O 1.95 is an attractive choice for use as a low temperature electrolyte and as an anode component in solid oxide fuel cells (SOFC).
Ceria particles can also be used as catalysts, such as three-way catalysts to purify exhaust gases, such as for automobiles. This application requires a high oxygen storage content (OSC). In order to improve the OSC, the ceria may be doped with lanthanide elements. The use of high surface area, nanocrystalline powder could benefit all of these applications.
Typically, processes for preparing nanocrystalline CeO 2 involve simple oxidation of Ce metal clusters to form CeO 2 , or solution processes that take advantage of the small solubility product of Ce(OH) 3 (10 −23 ). In addition, such processes involve reaction temperatures of 100° C. or higher. This results in larger particle sizes and lower surface area of the crystals. The particle size is inversely related to the specific surface area (“SSA”).
An example process is found in, U.S. Pat. No. 5,017,352 which discloses ceria having a SSA of at least 85±5 m2/g. The ceria particles are made from the hydrolization of cerium (IV) nitrate solution in an acidic medium and followed by calcining the washed and dried precipitate in the temperature range of 300° to 600° C. for a period of 30 minutes to ten hours. This basic process can also be used to produce ceria having a SSA of at least 130 m2/g as disclosed in U.S. Pat. No. 5,080,877. The ceria is formed by reacting an aqueous solution of cerium (IV) salt with an aqueous solution of sulfate ions to precipitate a basic ceric sulfate, washing the precipitate with ammonia and then calcined in a furnace at 400° C. for 6 hours.
It is also possible to generate single crystal grains ranging in size from 10 to 80 nm of cerium oxide that have a uniform particle size and shape. This is disclosed in U.S. Pat. No. 5,938,837 as being accomplished by mixing cerous nitrate with a base to keep the pH from 5 to 10 and then rapidly heating the mixture to 70° to 100° C. and maintaining the mixture at that temperature from about 30 minutes to 10 hours.
U.S. Pat. No. 4,786,325 discloses a method for the production of a solid solution of cerium oxide and a lanthanide series metal. This is achieved by combining a cerium salt, a basic solution, and a lanthanide salt. The mixture is reacted at either 10–25° C. or 40–95° C., filtered, dried, and calcinated at 600 to 1200° C. for a period of time of 30 minutes to 10 hours. The particles are ground so that their mean particle size is from 0.5 to 1.5 μm and the resulting SSA is from 2 to 10 m 2 /g.
U.S. Pat. No. 5,712,218 discloses a method for producing a solid solution of cerium/zirconium mixed oxides that optionally can include yttrium. The method involves mixing stoichiometric amounts of soluble compounds of cerium, zirconium and optionally yttrium, heating the mixture to at least 100° C., and filtering out the product. Optionally the product can be further calcinated at between 200° to 1000° C. However, it is disclosed that the calcinations process will reduce the surface area of the solid solution. The SSA of the uncalcinated solid solution can reach over 150 m 2 /g.
SUMMARY OF THE INVENTION
The present invention involves the use of a semi-batch reactor process to synthesize metal oxide particles with controllable particle size between 3 to 100 nm and with uniform particle size and shape. The invention will be described in detail with respect to the use of cerium, however the invention is applicable to the use of iron, chromium, manganese, niobium, copper, nickel, and titanium in place of or in combination with cerium. The basic process involves mixing a cerium salt and an alkali metal or ammonium hydroxide, which operates as a precipitant, to form a precipitate, and then filtering and drying the precipitate. The mixture is preferably constantly stirred at a rate that ensures turbulent conditions to enhance the mixing.
In carrying out the present invention a first solution of a water-soluble cerium salt is mixed with a second solution of an alkali metal or ammonium hydroxide are mixed together to form a reactant solution. While the reactant solution is agitated under turbulent flow conditions, oxygen is passed through the reactant solution. Cerium dioxide particles having a predominant particle size within the range of 3–100 nanometers are precipitated from the reactant solution. In a preferred embodiment of the invention, the second aqueous solution is an aqueous solution of ammonium hydroxide with a concentration of ammonium hydroxide in water within the range of 0.1 moles to 1.5 moles per liter. While ammonium hydroxide is preferred, other alkali metal hydroxides, such as sodium or potassium hydroxide, can be employed.
There are a number of variables involved in the mixing step that can be controlled in order to synthesize ceria particles of uniform shape at the desired particle size. First, the amount of oxygen gas that is bubbled through the reactor as the reactants are mixed will affect the particle size. Bubbling oxygen gas through the reactor decreases the particle size of the ceria particles. Using the oxygen gas allows the synthesis of ceria particles that are as small as 3 nm as opposed to particles that are 12 nm when oxygen is omitted. Second, adjusting the temperature at which the reaction takes place will also affect the particle size. This method will result in the synthesis of ceria particles of 15 nm at 20° C. and 50 nm sized particles of ceria at 70° C. In addition, heating the produced ceria particles for one hour will result in their coarsening to larger particle sizes depending on the temperature being used.
Finally, the order with which the two reactants are mixed will affect the pH value at which crystallization takes place. In the case of adding the precipitate into the salt (PIS), the pH starts out low, due to the slightly acidic nature of the cerium salt. As a result, while the primary particle size is approximately 10 nm, the agglomerates are large and non-uniform in shape. On the other hand, in the case of the addition of the salt into the precipitate (SIP), the pH remains higher than 9 during the entire reaction. This results in particle size approximately the same as the primary particle size from the PIS process, however, there is significantly less agglomeration and the particles were of uniform size and shape due to homogenous nucleation.
Consequently, by using this process, it is possible to synthesize ceria particles that have a uniform shape and size and whose size is controllable within the range of 3 nm to 100 nm.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of the reactor setup used to carry out this method
FIG. 2 is a schematic of the scale of the mixing steps
FIG. 3 is a TEM image of the powders prepared at high stirrer rate using SIP and bubbling oxygen through the reactor.
FIG. 4 is a graph of the pH evolution and the cerium ion dissipation in the PIS process without using oxygen.
FIG. 5 is a graph of the pH evolution and the cerium ion dissipation in the SIP process without using oxygen.
FIG. 6 is a TEM image of the powders prepared from the SIP process without using oxygen.
FIG. 7 is an X-ray diffraction pattern of the particles from the SIP process without using oxygen.
FIG. 8 is an X-ray diffraction pattern of the particles from the SIP process with the use of oxygen.
FIG. 9 is a graph of the variation of CeO 2 specific surface area and particle size vs. annealing temperature.
FIG. 10 is a graph of the variation of CeO 2 particle size in nanometers vs. temperature.
FIG. 11 is a TEM image of the disordering structure of nanometer CeO 2 particles.
FIG. 12 is an X-ray diffraction pattern of Sm doped CeO 2 , SmO 2 O 3 and CeO 2
DETAILED DESCRIPTION OF THE INVENTION
The liquid phase precipitation process of this method includes three mechanisms: chemical reaction, nucleation, and crystal growth. It was found that in most cases these three mechanisms are fast, hence the mixing procedure has a large influence on the product particle size and its distribution. Therefore, control over the nucleation and growth mechanisms are achieved by controlling the mixing conditions.
The prepared precursors for this method are: aqueous solution of ammonium hydroxide (0.1 to 1.5*10 −3 mol/g), cerium salt solution, preferably cerium nitrate hexahydrate, Ce(NO 3 ) 3 .6H 2 O, (GIF, 99.9%) solution (0.6 to 0.8*10 −3 mol/g), and nitrat acetates of lanthanide series metals as the dopant precursor. The use of excessive precipitant is preferred so that the pH value is ≈9 after the reaction is complete. The reaction can be carried out in a system as shown in FIG. 1 . The cerium salt and the ammonium hydroxide are fed into a semi-batch reactor 8 . This can be accomplished by placing the ammonium hydroxide solution in reactor 8 and placing the cerium salt in a precursor vessel 4 (SIP feeding). A Peristaltic pump 5 is provided to pump the solution from the precursor vessel 4 into reactor 8 at a fixed rate. Alternatively, the ammonium hydroxide can be placed into precursor vessel 4 and the cerium salt placed in reactor 8 (PIS feeding). Finally, there can be a second precursor vessel (not shown) and peristaltic pump (not shown) and each precursor can be separately fed into reactor 8 which would contain distilled water. It is preferred that the solutions being fed into the reactor by pump 5 is fed at a rate within the range of 0.5 to 10 ml/min. Any dopant precursor that is being used can either be added to the cerium salt solution or fed into the reactor from a separate precursor vessel by an additional peristaltic pump.
Impeller 3 is provided to maintain turbulent conditions in reactor 8 . It is powered by motor 2 that preferably has a 0–15000 rpm range and is preferably operated in the 100–5000 rpm range. Motor 2 is controlled by rate controller 1 . The stirring rate rapidly distributes the particles and prevents their concentration from being localized at the region near the feed point. This insures that micromixing is occurring as opposed to the slower macromixing that would otherwise occur as a result of the reaction only occurring at the surface of the drops of reactant. The scale of mixing is schematically depicted in FIG. 2 . An increase of the impeller speed to generate turbulent conditions does not change the primary particle size, but does significantly decrease the agglomerate size. The onset of turbulent flow occurs when the Ad Reynolds number, R e , is ≧1·10 4 . The Reynolds number is defined by
R e = D 2 N ρ μ ,
where D is the motor's impeller diameter (m), N is the impeller speed (rpm), ρ is the liquid density (kg/m 3 ) and μ is the liquid viscosity (cp). Returning to FIG. 1 , the rate controller 1 is used to keep impeller 3 at the proper rpm range to maintain turbulent conditions in reactor 8 . Rate controller 1 also automatically adjusts the power load to motor 2 in order to keep impeller 3 at a constant rpm as the viscosity of the slurry in reactor 8 changes.
FIG. 3 depicts a TEM micrograph of the resultant CeO 2 particles when impeller 3 was set at 500 rpm, which corresponds to a R e ≈1.3·10 4 . When the same method was used, with the exception that impeller 3 was set at 100 rpm, R e ≈2.6·10 3 , the primary particle size was the same, however the agglomerate size was significantly increased.
The order the reactants are added also plays an important role in the resulting powder. It appears that the nucleation and growth of the Ce(OH) 3 occurs at the droplet:reactant interface. The difference between whether the cerium salt is added to the ammonium hydroxide (SIP feeding) or the ammonium hydroxide is added to the cerium salt (PIS feeding) is the pH value at which crystallization takes place.
FIG. 4 shows a graph with the pH value on the first ordinate axis, time in minutes on the abscissa axis, and cerium hydroxide concentration on the second ordinate axis for the PIS feeding process. In PIS feeding, the pH value in the reactor is initially very low (pH ≈3.8–4.3 for the cerium nitrate solution), and increases rapidly with the addition of just a few drops of ammonium hydroxide to a value of approximately 7.2. Further additions resulted in a slight but steady increase in pH as the Ce +3 ions were consumed, with a sharp transition of pH when the reaction was close to the end. FIG. 4 also shows the evolution of the solubility product of [Ce +3 ][OH − ] 3 over the course of the reaction. This value is less then the critical solubility constant of Ce(OH) 3 , which is ≈7· −21 . Under these conditions, even though a nucleus may form at the drop:reactant interface, it is in an unstable state because of the low pH value of the bulk solution. This results in a redissolution process called ripening. Consequently the particles synthesized are highly agglomerated and non-uniform in shape.
As shown in FIG. 4 , which shows PIS feeding with no oxygen bubbling and the mixer set at 500 rpm, the reaction results in interesting color changes to the slurry. The slurry was initially purple in section a (low pH), transitioned to brown in section b (intermediate pH), and then turned yellow in section c (high pH). These color changes appear to relate to the valence state of the Ce, with most likely purple corresponding to Ce +3 , yellow corresponding to Ce +4 , and brown corresponding to a mix of these two states.
FIG. 5 is a graph showing pH value on the first ordinate axis, time in minutes on the abscissa axis, and cerium hydroxide concentration on the second ordinate axis for the SIP feeding process. During the SIP feeding process, the pH value always remains higher than 9 (i.e. [OH − ] higher than 10 −5 mol/l). This is shown in FIG. 5 which shows the pH and [Ce +3 ][OH − ] 3 concentration changes as the reaction progresses during the SIP feeding process, without any oxygen bubbling and with the mixer set at 500 rpm. As also shown in FIG. 5 , the slurry color changes immediately to brown upon the addition of the cerium salt (section ‘a’) and then turns light yellow (section ‘b’) over a period of only 1 minute.
Under the basic conditions during SIP feeding, the solubility product of [Ce +3 ][OH − ] 3 is much higher than the solubility constant (K sp ), meaning that the supersaturation value,
S = [ Ce 3 + ] [ OH - ] 3 K sp ,
is very large. This establishes an environment that favors homogenous nucleation. FIG. 6 is a TEM image of particles made using the SIP feeding process, without any oxygen bubbling and with the mixer set at 500 rpm. The result is primary particles that are ≈10 nm and which are of a uniform size and shape.
Returning to the system shown in FIG. 1 , it is advantageous to bubble oxygen gas through reactor 8 while carrying out the reaction. This is accomplished by adding oxygen gas through a stainless steel tube 6 and out a gas distributor 7 at a predefined rate. It is preferred that the oxygen is bubbled through the reactor within the range of 1–500 ml/min. In general, after filtration, a powder cake appears brown due to the presence of Ce(OH) 3 (purple) and CeO 2 (light yellow). After aging under ambient conditions, it transforms to a totally light yellow powder (CeO 2 ). Drying under a vacuum can accelerate this and results in large amounts of water condensing on the container walls. This appears to be caused by the reaction 2Ce(OH) 3 +½O 2 →2CeO 2 +3H 2 O. Therefore, bubbling O 2 during the mixing of the reactants can be applied to speed up this conversion of Ce(OH) 3 to CeO 2 .
This is illustrated by experimental work in which ammonium hydroxide was bubbled with oxygen for 1 minute and then the SIP process was engaged. Adding droplets of the Ce(NO 3 ) 3 .6H 2 O immediately turned the slurry purple and then over a period of approximately 30 seconds it transitioned through a dark brown to a light yellow color.
FIG. 7 is a graph of the XRD pattern from the SIP feeding process with the intensity on the ordinate axis and 2θ on the abscissa axis. The process was carried out at room temperature and with stirring at 500 rpm's without any use of oxygen. It shows a resulting particle size of 5 nm. FIG. 8 is another graph showing the XRD pattern with the intensity on the ordinate axis and 2θ on the abscissa axis. The process used in FIG. 8 is the identical process used in FIG. 7 except that oxygen was bubbled through the solution during the reaction. The particle size in this case is 3 nm and the particles are less agglomerated as shown in FIG. 6 , which is a TEM image of the resulting particles. However, the powder shown in FIG. 7 , while being more agglomerated than the powder shown in FIG. 8 , is only lightly agglomerated, and can be easily re-dispersed in a solution.
It appears that bubbling the oxygen gas simply maintains the equilibrium concentration of oxygen gas that is dissolved in the solution. This is because the overall results indicate that the nucleation step is the fastest, meaning that Ce(OH) 3 formation is immediate and would not be impacted by the presence of an O 2 bubble. The oxidation reaction can either take place at the surface of the O 2 bubble or with dissolved O 2 . The equilibrium concentration of oxygen in water-ammonium hydroxide solutions ranges from 10 to 25 ppm. In a 500 ml reactor and a typical batch size of approximately 10 grams of Ce(OH) 3 , this would not be sufficient fully oxidize all of the Ce(OH) 3 to CeO 2 . The bubbling O 2 would replenish the dissolved O 2 in the solution and allow this reaction to continue to completion faster. In any case, the use of O 2 bubbling during the SIP process yields the finest and least agglomerated CeO 2 powder.
In the system shown in FIG. 1 , reactor 8 is maintained at a constant temperature, preferably room temperature, through a temperature controller 9 . Varying the temperature that the reaction is carried out at affects the particle size that is synthesized. In experimental work carried out at 70° C. the particles of CeO 2 were 50 nm. The same process carried out at 20° C. resulted in particles that were only 15 nm. As can be seen, the smallest particle sizes occur around room temperature, so no heating is needed in order to generate the smallest particle sizes. However, the temperature of the reactor can be increased in order to synthesize particles of CeO 2 powder of a desired larger size.
In addition, the particles synthesized with this process will coarsen when heated. FIG. 9 is a graph showing the BET specific surface area (m 2 /g) on the first ordinate axis, temperature (C°) on the abscissa axis and particle size (nm) on the second ordinate axis. It shows the SSA and the corresponding particle size for annealing temperatures ranging from 150° to 800° C., all for a 1-hour soak time. FIG. 9 shows that the particle size increases slowly from 4 nm up to 10 nm at 500° C. and then begins to rapidly increase to reach 100 nm at 800° C. This information can be plotted in an Arrhenius manner as is shown in FIG. 10 , which is a graph showing the natural log of the particle size (nm) on the ordinate axis and the inverse of the annealing temperature (C°) on the abscissa axis, to show two distinct linear regions. The activation energy in the low temperature range is 2.4 kJ/mol and in the high temperature range the activation energy is 63.4 kJ/mol. Therefore, it appears that there are two different mechanisms for crystal growth at the different temperatures, which can be used to generate ceria particles of the desired size.
FIG. 11 is a TEM lattice image of a collection of CeO 2 primary particles after room temperature drying. It can be seen that there are many crystal regions (supporting the XRD data) but there is also a large fraction of the ensemble in disorder, perhaps even amorphous. This state likely provides a large driving force for diffusion and subsequent growth at higher temperatures. Lattice diffusion typically has a lower activation energy then other mechanisms so it is possible that simple atomic rearrangement and ordering results in the slow crystal increase at lower temperatures. At higher temperatures, boundary diffusion possibly controls the particle size evolution because of the higher energy associated with long range ordering and particle rearrangement. Therefore, this data can be used to pick an annealing temperature that will result in crystal growth to the desired size.
As disclosed above, many of the applications for CeO 2 utilize the high ionic conductivity that can be achieved by acceptor doping with lanthanide elements such as La 3+ , Sm 3+ , and Gd 3+ . Of these, Sm 3+ yields the highest ionic conductivity. During the SIP process the supersaturation values for Ce 3+ ranges from 1.4·10 13 ˜1.4·10 10 depending on how much the Ce 3+ diffuses through the reactor when it is added to the ammonium hydroxide. Using the K sp values from Table I, the supersaturation value for Sm 3+ is 5.4·10 11 . The theoretical and calculated values differ somewhat in Table I most likely due to the assumption of equilibrium for the calculated values. As a result of the supersaturation values, during SIP feeding, it appears that Ce 3+ and Sm 3+ precipitate simultaneously. In addition, FIG. 12 is a graph showing of a number of ERD patterns with the intensity on the ordinate axis and 2θ on the abscissa axis. FIG. 12 shows the XRD patterns of the as-synthesized (i.e. not thermally annealed) Ce 1−-x Sm x O 2 (x=0.02, 0.05, 0.10, and 0.20) and Sm 2 O 3 , along with CeO 2 annealed at 800° C. for reference. Clear shifts in the diffraction peaks are evident as greater amounts of [Sm 3+ ] were added. This establishes that a solid solution has formed. Similar results were achieved for La 3+ and Gd 3+ doped CeO 2 .
TABLE I
Experimental
Calculated
Element
K sp
K sp
La
1.10E−19
5.01E−21
Ce
7.00E−21
1.26E−20
Sm
4.60E−23
3.16E−17
Gd
1.80E−23
2.51E−16
On the other hand, the supersaturation values for PIS feeding (pH=7.3) are 1.1 for Ce 3+ and 43.2 for Sm 3+ , for [Ce 3+ ]=1.0 mol/l and [Sm 3+ ]=0.25 mol/l. These conditions resulted in the successive precipitation of Ce 3+ and Sm 3+ hydroxides and consequently cation segregation in the dried powder. However due to the fine particle size, it is believed that at relatively low temperatures a solid solution would form.
The particle size and morphology were determined by transmission electron microscopy (TEM, Philips EM420). Samples for the TEM were prepared by ultrasonically dispersing the powders in ethanol, and then droplets were placed on carbon-coated Cu grids. Corresponding electron diffraction patterns (EDF) were used to characterize the particle crystallinity, as well as X-ray diffractometry (XRD; Scintag 2000). The specific surface area (SSA) is inversely related to the particle size and is calculated by the Brunauer-Emmett-Teller (BET) method. (Quantachrome; Nova 1000).
The particle size = 6 ρ · SSA
where ρ is the density of the powders (g/cm 3 ).
The theoretical density of CeO 2 was calculated using the lattice parameters calculated from the XRD pattern. X-ray line broadening (20°≦2θ≧100°) was used to calculate the x-ray coherence length, which corresponds to the particle size after correcting for strain effects using the Lorentz intensity breadth. The theoretical densities ρ th , (kg/m 3 ) of the lanthanide doped CeO 2 compositions were calculated by
ρ th = 4 n A a 3 [ M Ce ( 1 - x ) + M L n x + M O ( 2 - 0.5 x ) ] ,
where M Ce , M Ln and M O are the molecular weights of the sub-species in kg/mole, n A is Avogadro's number (6.023·10 23 /mole), and ‘a’ (meters) is the XRD lattice parameter. All lanthanide elements were assumed to be in the 3+valance state.
The crystal grain size was determined by powder x-ray diffraction, analyzing the pattern by simulation based upon the Gaussian and Lorentz distribution after correcting for the strain effect. The equation, which was used, is shown as:
β total = β XRCL + β Strain = 0.9 λ t cos θ + 4 ( Δ d ) d tan θ .
A plot of β total (cos θ) vs. sin θ has the intersection of 0.9 λ/t, where λ is the wavelength of generated x-ray and t is the sample x-ray coherence length, i.e. the crystal grain size. This was compared to the particle size calculated above to ensure that each particle was a single grain crystal.
In order to further illustrate the present invention and the advantages thereof, the following specific examples are given, it being understood that same are intended only as illustrative and in no way limiting:
EXAMPLE 1
Ammonium hydroxide aqueous solution with a concentration of 1.5·10 −3 mol/g was placed in a semi-batch tank reactor. A 0.5·10 −3 mol/g solution of cerium nitrate aqueous solution was the fed into the reactor (SIP feeding). There was a 20% excess of the ammonium hydroxide solution. The feeding rate was controlled by a peristaltic pump supplied by Fisher. The ammonium hydroxide solution was constantly stirred at a rate of 300 rpm with the power load of the stirrer being automatically adjusted with the changing viscosity of the slurry in the reactor. The reactor temperature was set at room temperature. Oxygen was bubbled into the reactor at a rate of 20 l/min as controlled by a gas flow-meter. The slurry was vacuum filtered and then vacuum dried at room temperature. The SSA data were found to be about 150 m 2 /g and the TEM microscopy photos showed that the particle size is around 3–5 nm. This was confirmed to be the same size as a single crystal from the x-ray diffraction pattern.
EXAMPLE 2
The same setup as in example 1 is used. This time PIS feeding was used with ammonium hydroxide aqueous solution used as the feeding precursor and cerium nitrate solution in the reactor. The feeding rate was controlled between 0.5 ml/min to 8 ml/min. At a reactor temperature of 70° C. the average synthesized particle size was 50 nm and at a reactor temperature was of 20° C. the average particle size was 15 nm.
EXAMPLE 3
PIS feeding was carried out as in example 1 at room temperature, a feeding rate of 5 ml/min and a stirrer rate of 1000 rpm. When oxygen was bubbled through the reactant mixture the smallest particle size obtained was 4 nm. Without the use of oxygen the smallest particle size obtained was 12 nm.
EXAMPLE 4
The method used in Example 1 was repeated using double feeding, which is where ammonium hydroxide aqueous solution and cerium nitrate solution are both used as feeding solutions into a reactor that contains distilled water. The feeding rate was kept in the range of 1 ml/min to 8 ml/min. The temperature was 25° C. and the mixture was stirred to establish turbulent conditions. The average particle size is 10 nm. Oxygen was not used in this example.
EXAMPLE 5
Solid solutions were observed using the above method with the Lanthanide element in a nitrate or acetate compound that was dissolved in water to form an aqueous solution, which was used as the dopant precursor.
a. Niobium-citric acid aqueous solution was used as the precursor in the double feeding method to form niobium and cerium mixed compounds. These compounds were transferred to solid solution after being sintered.
b. Yttrium nitrate or acetate aqueous solution was used as the lanthanum dopant precursor and mixed with the cerium nitrate solution. This mixed solution was used as the feeding solution in SIP feeding. A solid solution resulted from the reaction.
c. Zirconia hydroxy acetate aqueous solution or the acetate aqueous solution was used as the dopant precursor and mixed with the cerium nitrate aqueous solution. This mixed solution was used as the feeding solution in SIP feeding. A solid solution resulted from the reaction.
d. Double feeding of the doped element precursors from a, b, and c were used as a separate feeding solution in double feeding method. The solution in the reactor was distilled water. The reaction resulted in the formation of a solid solution in each of the cases.
Having described specific embodiments of the invention, it is understood that modifications thereof may be suggested by those skilled in the art, and it is intended to cover all such modifications as filed within the scope of the appended claims. | 4y
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a reception apparatus for a radio communication system which utilizes a minimum preamble signal to assure a high efficiency in high speed transmission in a multi-path environment, and more particularly to a technique for high speed equalization processing and a technique for reduction of the power consumption.
2. Description of the Related Art
In data transmission of a high speed radio ATM (Asynchronous Transfer Mode) system which is one of multimedia mobile communication systems of 20 to 30 Mbps (megabits/second: unit of the transmission rate) and uses the 5.2 GHz band, in order to prevent quality deterioration of data by multi-path fading, an equalization function is used, and in order to allow high speed processing of an equalizer, a minimum preamble signal is used.
As an apparatus of the type described, for example, a radio data communication terminal of the narrow-band modulation type is disclosed in Japanese Patent Laid-Open No. 308158/1999 which can use a minimum preamble to determine a frequency offset value for operating a phase rotating element and then set a tap coefficient to be used by an equalizer. More particularly, the radio data communication terminal determines a frequency offset value for operating an automatic frequency control circuit within a preamble period of one frame period in accordance with a narrow-band modulation system wherein NRZ (Non-Return to Zero) codes of the opposite polarities of the GMSK (Gaussian filtered MSK (Minimum Shift Keying)) are passed through a low-pass filter of the Gaussian type and then inputted to a phase-continuous FSK (Frequency Shift Keying) modulator of a modulation index of 0.5 to modulate the codes, estimates the transmission line characteristic, determines a tap coefficient necessary for an equalizer, sets the tap coefficient to the equalizer and then performs equalization of a reception signal by means of the equalizer.
FIG. 4 shows an example of a configuration of an equation function of a conventional radio reception apparatus which uses a minimum preamble to determine a frequency offset value for operating a phase rotating element and then sets a tap coefficient to be used by an equalizer.
Referring to FIG. 4 , the radio reception apparatus shown includes two first and second antennae 8 a and 8 b , a radio frequency (RF) section 9 , a carrier detection section 10 , an equalization processing section 11 . The equalization processing section 11 includes a memory section 12 , a phase rotating section 13 , a phase difference detection section 14 , an average value detection section 15 , an integration circuit 16 , a vector conversion circuit 17 , a transmission line characteristic estimation section 18 , a tap coefficient setting section 19 , and an equalizer 20 .
Transmission data from a base station are received by the two antennae 8 a and 8 b . The RF section 9 receives the reception data from the antennae 8 a and 8 b , performs a frequency conversion process and outputs the reception data of the converted frequency (quadrature demodulated I and Q signals) to the equalization processing section 11 . The RF section 9 outputs a received signal strength indicator (RSSI) signal Q to the carrier detection section 10 .
The carrier detection section 10 discriminates presence/absence of a carrier based on the RSSI signal Q from the RF section 9 , and outputs, to the equalization processing section 11 , a carrier sense signal S which exhibits an active state when a start of receive data is detected. Further, the carrier detection section 10 receives a demodulation data end signal R of a one-pulse signal representative of an end of demodulation data supplied thereto and outputs, to the equalization processing section 11 , the carrier sense signal S serving as a control signal for stopping the outputting of demodulation data from the equalization processing section 11 .
The memory section 12 fetches a reception data signal P (quadrature demodulation signal after conversion into a digital signal by an A/D conversion section not shown) for an arbitrary period of time and controls the outputting.
The phase rotating section 13 rotates the phase of the output signal of the memory section 12 by a necessary amount. The phase difference detection section 14 determines an angle at present and another angle after one period of a PN (Pseudo Noise) code string and determines a difference between the angles.
The average value detection section 15 integrates the value of the angle difference determined by the phase difference detection section 14 for a predetermined number of times and then divides the integrated value by the number of times to determine an average value (frequency offset value) of an average phase difference per one symbol. The integration circuit 16 integrates the frequency offset value determined by the average value detection section 15 in a unit of a symbol. The vector conversion circuit 17 converts a signal outputted from the integration circuit 16 into a real part amplitude value and an imaginary part amplitude value and outputs the real part amplitude value and the imaginary part amplitude value to the phase rotating section 13 . The transmission line characteristic estimation section 18 uses the signal after the phase rotation by the phase rotating section 13 to determine a transmission line characteristic for one period of the PN code string within the preamble period. The tap coefficient setting section 19 determines a tap coefficient necessary for the equalizer 20 from the transmission line characteristic determined by the transmission line characteristic estimation section 18 and sets the tap coefficient to the equalizer 20 . The equalizer 20 equalizes the output of the phase rotating section 13 by means of a filter having the tap coefficient set by the tap coefficient setting section 19 and outputs a demodulation data signal T to effect a reception process.
FIG. 5 illustrates an example of operation timings in an equalization function process of the radio reception apparatus shown in FIG. 4 . Referring to FIG. 5 , within an antenna changeover selection period δ of a preamble signal period γ positioned preceding to an information data period, the integration is performed on the antenna 8 a side for a certain fixed period for each one frame, and then the antenna to be used is changed over to the antenna 8 b . After the changeover, the integration is performed on the antenna 8 b side for another certain fixed period. The integration output values integrated for the first antenna 8 a side and the second antenna 8 b side are compared with each other to select the antenna which exhibits a higher reception level. Then, the antenna to be used is fixed to the selected antenna, and burst reception (reception of information data) is performed using the selected antenna.
Within the preamble signal period γ, the carrier detection section 10 discriminates presence/absence of a carrier to detect a start of reception data, and then automatic gain control (AGC) and automatic frequency control (AFC) by an automatic frequency control circuit (not shown) for dealing with amplitude and phase variations in demodulation processing are performed. Further, the equalization processing section 11 performs detection of a frequency offset, estimation of a transmission line characteristic and setting of a tap coefficient.
FIG. 6 illustrates an example of reception timings of the conventional radio reception apparatus shown in FIG. 4 when an idle time is comparatively long. The reception data signal P successively received from the RF section 9 is composed of a preamble signal used for various kinds of training and information data. Within a preamble period placed before an information data period within one frame period, the same PN string is transmitted repetitively. The carrier detection section 10 discriminates presence/absence of a carrier based on the RSSI signal Q from the RF section 9 to detect a start of reception data, and after a start of reception data is detected, that is, after the carrier sense signal S outputted from the carrier detection section 10 changes into an active state, the equalization processing section 11 performs detection of a frequency offset, estimation of a transmission line characteristic and setting of a tap coefficient.
In the initialization of the equalizer 20 , a preamble signal which includes repetitions of a PN code is stored into the memory section 12 and processed for a certain fixed time, and therefore, a delay appears as much. The demodulation data signal T is outputted after the initialization of the equalizer 20 . As seen from FIG. 6 , a delay corresponding to the initialization period of the equalizer 20 occurs at the equalization processing section 11 , and the transmission efficiency is deteriorated because the idle period is long.
FIG. 7 illustrates an example of reception timings of the conventional radio reception apparatus shown in FIG. 4 when the idle period is short. The reception data signal P successively received from the RF section 9 is composed of a preamble signal used for various kinds of training and information data. After presence/absence of a carrier is discriminated based on the RSSI signal Q from the RF section 9 to detect a start of reception data, the equalization processing section 11 performs detection of a frequency offset, estimation of a transmission line characteristic and setting of a tap coefficient. In the initialization of the equalizer 20 , a preamble signal which exhibits repetitions of a PN code is stored into the memory section 12 and processed for a certain fixed period of time. Therefore, a delay for approximately 200 symbols in the maximum occurs. The demodulation data signal T is outputted after the initialization of the equalizer 20 is performed.
If the idle period is shorter than the delay and a next frame is received within a carrier sense period ε, then the carrier sense signal ζ at a rising edge cannot be detected due to a collision of the frames. Reception data for one frame within which the carrier sense signal ζ is not successfully detected at a rising edge cannot be received normally, and a miss of one frame occurs with the demodulation data signal.
The conventional reception apparatus shown in FIG. 4 cannot perform high speed reception since the preamble signal is longer by the antenna changeover selection period δ of the preamble signal period γ. On the other hand, where the idle period from the end of information data to the start of the preamble period of the next frame is short, reception data cannot be received normally.
In the conventional radio reception apparatus described with reference to FIGS. 4 to 6 , integration output values integrated for the antenna 8 a side and the antenna 8 b side are compared with each other to select that one of the antennae which exhibit a higher reception level (reception sensitivity) within the antenna changeover selection period δ within the preamble signal period γ within which various kinds of training are performed, and then AGC and AFC as well as initialization necessary for the equalizer are performed. Therefore, the preamble signal becomes longer by the antenna changeover selection period δ, and this deteriorates the transmission efficiency. Then, where the idle period is comparatively long, the transmission efficiency is deteriorated. On the other hand, where the idle period is comparatively short, if the idle period is shorter than a delay time and a next frame is received within a processing period of demodulation data, then a carrier sense signal cannot be detected. Consequently, such a problem occurs that reception data are received but abnormally for every other frame.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a radio reception apparatus and a high speed equalization process therefor by which a delay caused by initialization of an equalizer is minimized.
It is another object of the present invention to provide a radio reception apparatus and a high speed equalization process therefor wherein an equalization process with a minimum preamble signal can be performed normally to assure a high transmission efficiency and suppress an increase of the power consumption.
In order to attain the object described above, according to an aspect of the present invention, there is provided a radio reception apparatus, comprising first and second antennae for receiving data from a transmission side, a first radio frequency (hereinafter referred to as RF) section for performing a frequency conversion process of the reception data from the first antenna, a second RF section for performing a frequency conversion process of the reception data from the second antenna, first and second carrier detection sections for discriminating presence/absence of a carrier based on received signal strength indicator (hereinafter referred to as RSSI) signals from the first and second RF sections, respectively, a comparison section for comparing reception levels of the RSSI signals from the first and second RF sections with each other to select that one of the RSSI signals which has a higher reception level and supplying a signal representative of the selected reception level to that one of the first and second carrier detection sections which corresponds to that one of the first and second RF sections from which the selected signal has been outputted, an equalization processing section including an equalizer, and control means for supplying, based on carrier sense signals outputted from the first and second carrier detection sections, the reception data signal outputted from that one of the first and second RF sections which has a higher reception sensitivity to the equalization processing section and controlling the equalization processing section to operate based on the reception data signal.
The control means may include first and second logic circuits provided corresponding to the first and second carrier detection sections, respectively, each for controlling so that a reception data signal outputted from a corresponding one of the first and second RF sections corresponding to the first and second carrier detection sections may pass therethrough and be outputted within a period within which the carrier sense signal outputted from a corresponding one of the first and second carrier detection sections is active, a third logic circuit for logically ORing the outputs of the first and second logic circuits and outputting a result of the logical ORing as a reception data signal to the equalization processing section, and a fourth logic circuit for logically ORing the carrier sense signals outputted from the first and second carrier detection sections and outputting a result of the logical ORing as a signal for controlling operation of the equalization processing section to the equalization processing section.
The comparison means may supply, to that one of the first and second carrier detection sections which corresponds to that one of the first and second RF sections which has a higher reception sensitivity, a signal indicative of the reception level from the RF section, but supply, to the other one of the first and second carrier detection sections which corresponds to the other RF section which has a lower reception sensitivity, a signal of a level for rendering inactive the carrier sense signal to be outputted from the carrier detection section.
The equalization processing section may perform detection of a frequency offset, estimation of a transmission line characteristic and setting of a tap coefficient based on the reception data signal from the third logic circuit and the signal from the fourth logic circuit, and, after necessary initialization for the equalizer, output a demodulation data signal to perform a reception process.
Each of the first and second carrier detection sections may receive a demodulation data end signal, which is inputted commonly to the first and second carrier detection sections, and render inactive the carrier sense signal to be outputted.
According to another aspect of the present invention, there is provided a radio reception apparatus, comprising first and second antennae for receiving data from a transmission side, a first RF section for performing a frequency conversion process of the reception data from the first antenna, a second RF section for performing a frequency conversion process of the reception data from the second antenna, a comparison section for comparing a reception sensitivity of an output signal of the first RF section and a reception sensitive of an output signal of the second RF section with each other to select that one of the output signals which has a higher reception sensitivity, first and second carrier detection sections for outputting an output signal of an active state when a start of reception data is detected based on an output signal of the comparison section but rendering the output signal inactive when a demodulation data end signal is received, a first OR circuit for logically ORing the output signal of the first carrier detection section and the output signal of the second carrier detection section and outputting a result of the logical ORing, a first AND circuit for receiving the output signal of the first RF section and the output signal of the first carrier detection section and outputting the output signal of the first RF section within a period within which the output signal of the first carrier detection section is active, a second AND circuit for receiving the output signal of the second RF section and the output signal of the second carrier detection section and outputting the output signal of the second RF section within a period within which the output signal of the second carrier detection section is active, a second OR circuit for logically ORing the output signal of the first AND circuit and the output signal of the second AND circuit and outputting a result of the logical ORing, and an equalization processing section for receiving the reception data signal outputted from the first OR circuit and performing an equalization process for the received reception data based on the output signal of the second OR circuit.
The radio reception apparatus are advantageous in that, since the two systems of the RF sections are provided in parallel, a delay caused by initialization of the equalizer can be reduced. The radio reception apparatus are advantageous also in that, since that one of the antennae which has a higher reception sensitivity is selected for each one frame and also equalization processing with a minimum preamble signal is processed normally, a high transmission efficiency can be achieved. Further, the radio reception apparatus are advantageous in that, since only output reception data of that one of the RF sections which has a higher reception sensitivity are selectively used, the power consumption can be reduced.
The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings in which like parts or elements are denoted by like reference symbols.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing a radio reception apparatus to which the present invention is applied;
FIG. 2 is a diagrammatic view illustrating operation timings of the radio reception apparatus of FIG. 1 ;
FIG. 3 is a waveform diagram illustrating reception timings of the radio reception apparatus of FIG. 1 ;
FIG. 4 is a block diagram showing an equalization processing section of a conventional radio reception apparatus;
FIG. 5 is a diagrammatic view illustrating operation timings of the equalization processing section shown in FIG. 4 ;
FIG. 6 is a waveform diagram illustrating operation timings of the conventional radio reception apparatus of FIG. 4 when the idle period is comparatively long; and
FIG. 7 is a waveform diagram illustrating operation timings of the conventional radio reception apparatus of FIG. 4 when the idle period is comparatively short.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 , there is shown a radio reception apparatus to which the present invention is applied. The radio reception apparatus shown includes first and second antennae 1 a and 1 b for receiving data from the transmission side, first and second RF sections 2 a and 2 b for converting the frequency of reception data from the first and second antennae 1 a and 1 b , respectively, a comparison section 3 for comparing the magnitudes of the reception sensitivity α of an output signal of the first RF section 2 a and the reception sensitivity β of an output signal of the second RF section 2 b with each other to select that one of the output signals which has a higher reception sensitivity, first and second carrier detection sections 4 a and 4 b for detecting a start of reception data based on an output signal of the comparison section 3 and outputting an output signal of an active state and for receiving a demodulation data end signal and placing the output signal into an inactive state, a first OR circuit 5 a for outputting a result of logical ORing of output signals of the first carrier detection section 4 a and the second carrier detection section 4 b , a first AND circuit 6 a for receiving an output signal of the first RF section 2 a and an output signal of the first carrier detection section 4 a and outputting the output signal of the first antenna 1 a within a period within which the output signal of the first carrier detection section 4 a is in an active state, a second AND circuit 6 b for receiving the output signal of the second RF section 2 b and the output signal of the second carrier detection section 4 b and outputting the output signal of the second RF section 2 b within a period within which the output signal of the second carrier detection section 4 b is in an active state, a second OR circuit 5 b for outputting a result of logical ORing of output signals of the first AND circuit 6 a and the second AND circuit 6 b , and an equalization processing section 7 for receiving a reception data signal outputted from the second OR circuit 5 b and equalizing the received reception data based on the output signal of the first OR circuit 5 a.
The equalization processing section 7 receives a reception data signal L from the second OR circuit 5 b , performs detection of a frequency offset, estimation of a transmission line characteristic and setting of a tap coefficient based on a carrier sense signal H from the first OR circuit 5 a , and outputs, after the setting of the equalizer, a demodulation data signal M to perform a reception process.
Transmission data from a base station are received by the two first and second antennae 1 a and 1 b . The first RF section 2 a performs frequency conversion processing of reception data from the first antenna 1 a and outputs an RSSI signal A representative of a start of reception data to the comparison section 3 . The second RF section 2 b performs frequency conversion processing of reception data from the second antenna 1 b and outputs an RSSI signal B representative a start of reception data to the comparison section 3 .
The comparison section 3 compares the RSSI signal A from the first RF section 2 a and the RSSI signal B from the second RF section 2 b with each other to select that one of the two signals which has a higher reception level. More particularly, the comparison section 3 compares the reception sensitivity α of the RSSI signal A and the reception sensitivity β of the RSSI signal B with each other, and when the reception sensitivity α is equal to or higher than the reception sensitivity β, the comparison section 3 outputs an RSSI signal C (=RSSI signal A) to the first carrier detection section 4 a and outputs an RSSI signal D of a low level signal to the second carrier detection section 4 b . On the other hand, when the reception sensitivity α is lower than the reception sensitivity β, the comparison section 3 outputs the RSSI signal D (=RSSI signal B) to the second carrier detection section 4 b and outputs the RSSI signal C of a low level signal to the first carrier detection section 4 a.
The first carrier detection section 4 a discriminates presence/absence of a carrier from the RSSI signal C from the comparison section 3 . If the first carrier detection section 4 a detects a start of reception data, then it outputs a carrier sense signal F of an active state (of the high level). Then, when a demodulation data end signal E of a one-pulse signal representative of an end of demodulation data is received, the first carrier detection section 4 a places the carrier sense signal F into an inactive state and supplies it to the first OR circuit 5 a and the first AND circuit 6 a.
The second carrier detection section 4 b discriminates presence/absence of a carrier from the RSSI signal D from the comparison section 3 . If the second carrier detection section 4 b detects a start of reception data, then it outputs a carrier sense signal G of an active state (of the high level). Then, when the demodulation data end signal E of a one-pulse signal representative of an end of demodulation data is received, the second carrier detection section 4 b places the carrier sense signal G into an inactive state and supplies it to the first OR circuit 5 a and the second AND circuit 6 b.
The first OR circuit 5 a logically ORs the carrier sense signal F from the first carrier detection section 4 a and the carrier sense signal G from the second carrier detection section 4 b and outputs a result of the logical ORing as a carrier sense signal H to the equalization processing section 7 . In other words, the first OR circuit 5 a selectively outputs one of the carrier sense signal G and the carrier sense signal H which has a higher reception sensitivity to the equalization processing section 7 .
The first AND circuit 6 a logically ANDs a reception data signal J from the first RF section 2 a and the carrier sense signal F from the first carrier detection section 4 a and outputs the reception data signal J to the second OR circuit 5 b only within a period within which the carrier sense signal F is active.
The second AND circuit 6 b logically ANDs a reception data signal K from the second RF section 2 b and the carrier sense signal G from the second carrier detection section 4 b and outputs the reception data signal K only within a period within which the carrier sense signal G is active.
The second OR circuit 5 b logically ORs the outputs of the first AND circuit 6 a and the second AND circuit 6 b and outputs a result of the logical ORing as a reception data signal L to the equalization processing section 7 . In other words, that one of the reception data signals which has a higher reception sensitivity is selectively supplied as a reception data signal L to the equalization processing section 7 .
The equalization processing section 7 performs detection of a frequency offset, estimation of a transmission line characteristic and setting of a tap coefficient based on the reception data signal L from the second OR circuit 5 b and the carrier sense signal H from the first OR circuit 5 a . After the initialization of the equalizer, the equalization processing section 7 outputs a demodulation data signal M to perform a reception process. In the radio reception apparatus of FIG. 1 , the equalization processing section 7 may have, for example, a similar configuration to that described hereinabove with reference to FIG. 4 and include a memory section 12 , a phase rotating section 13 , a phase difference detection section 14 , an average value detection section 15 , an integration circuit 16 , a vector conversion circuit 17 , a transmission line characteristic estimation section 18 , a tap coefficient setting section 19 and an equalizer 20 as seen in FIG. 4 . Operation of the components is similar to that described in the description of the related art hereinabove, and therefore, overlapping description of the operation is omitted here to avoid redundancy.
FIG. 2 illustrates operation timings of the radio reception apparatus of FIG. 1 . Referring to FIG. 2 , in the radio reception apparatus of FIG. 1 , the carrier sense signal F of the first antenna 1 a side and the carrier sense signal G of the second antenna 1 b side are normally outputted within a one-frame period.
For each one frame, that one of the first antenna 1 a side and the second antenna 1 b side which exhibits a higher reception level is selected, and while the antenna to be used is fixed to the selected antenna, burst reception is performed.
Within the preamble signal period γ, presence/absence of a carrier is discriminated. After a start of reception data is detected, automatic gain control (AGC) and automatic frequency control (AFC) for dealing with amplitude and phase variations in a demodulation process are performed. Further, detection of a frequency offset, estimation of a transmission line characteristic and setting of a tap coefficient (filter coefficient for a transversal filter which forms the equalizer) are performed.
Use of the two parallel RF sections allows further shortening of the preamble signal. In particular, when compared with a case wherein, within an antenna changeover selection period δ of the preamble signal period γ, integration is performed on the antenna 8 a side for a certain fixed period for each one frame and the antenna to be used is changed over to the antenna 8 b and then, after the changeover, the integration is performed on the antenna 8 b side for another certain fixed period, whereafter the integration output values are compared with each other to select the antenna which exhibits a higher reception level and then the antenna to be used is fixed to the selected antenna and burst reception is performed using the selected antenna, in the radio reception apparatus, that one of the first antenna 1 a and the second antenna 1 b which outputs a higher one of reception levels outputted in parallel from them is selected. Consequently, the preamble period is reduced.
FIG. 3 illustrates reception timings of the radio reception apparatus of FIG. 1 . Referring to FIG. 3 , the reception data signal L successively received from the second OR circuit 5 b includes a preamble signal to be used for various kinds of training and information data. The preamble signal includes repetitions of a PN code for a fixed period of time.
After the carrier sense signal H rises, detection of a frequency offset value, estimation of a transmission line characteristic and setting of a tap coefficient are performed with a signal of the PN code for one period.
Initialization of the equalizer suffers from a delay corresponding to 96 symbols in the maximum because the signal is processed after it is stored into the memory (memory section 12 of FIG. 4 ) provided in the equalization processing section 7 . In other words, when compared with the conventional radio reception apparatus described hereinabove with reference to FIG. 4 , the delay is reduced approximately to one half, and consequently, the carrier sense signal can be detected.
Simultaneously with an end of demodulation data, the first and second carrier detection sections 4 a and 4 b place the carrier sense signal F and carrier sense signal G to the low level, respectively, and consequently, the carrier sense signal H is placed into an inactive state (the low level).
The comparison section 3 selectively outputs that one of the RSSI signals which exhibits a higher reception sensitivity, but does not select the other RSSI signal having a lower reception sensitivity and changes it into a low level signal.
Due to the parallel circuit configuration of the first RF section 2 a and the second RF section 2 b , even if an equalization process is performed with a minimum preamble signal, a reception process can be performed normally. Further, since that one of the first antenna 1 a and the second antenna 1 b which has a higher reception sensitivity is selectively used, even if a delay is caused by initialization of the equalizer, a normal reception process can be achieved.
In the radio reception apparatus of FIG. 1 , since output reception data of the RF section of one of the systems of the first RF section 2 a and the second RF section 2 b which has a higher reception sensitivity is selectively rendered operative (activated), the power consumption can be reduced.
While a preferred embodiment of the present invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims. | 4y
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BACKGROUND OF THE INVENTION
The present invention relates to a selection device for candy and other sweet confections. The term "selection device" is used to denote an apparatus designed to receive confections, arrange them in orderly fashion if appropriate, and convey them toward a further handling machine, eliminating those of substandard shape and size together with any unwanted fragments and powdered matter.
Conventional devices for the selection of sweet confections generally comprise an infeed chute from which the confections are dispensed loose, usually by free fall, onto a substantially horizontal table provided with a plurality of rectilinear vibrating conveyors. Confections received in this manner by the conveyors are carried along the table toward and ultimately into contact with a plurality of obstacles; these match the conveyors in number and consist in elements substantially of wedged shape, each one of which is installed in a fixed position over the relative conveyor. By causing interference between the wedges and the confections in a given manner, substandard pieces can be removed from the conveyors while allowing the regular confections through to a further production line machine. Conventional devices of the type thus outlined are beset by a number of drawbacks, amongst which, for example, excessive bulk, high noise levels, and the need for frequent stoppages to effect cleaning and servicing operations.
In effect, the selection of candy confections using this rectilinear conveyor table system necessarily dictates equipment of considerable longitudinal dimensions; the high noise levels are produced as the result of using vibrating conveyors, whilst the frequent stoppages are dictated by difficulties encountered in clearing the table of fragments shed by substandard confections, and of powdered waste matter.
It will be observed, in fact, that such waste matter consists largely in sugary substances that are ruinous to moving machine parts, and must therefore be removed periodically if the parts in question are not to seize up altogether. Accordingly, the object of the present invention is to embody a selection device for sweet confections that remains free of the drawbacks mentioned.
SUMMARY OF THE INVENTION
The stated object is realized with a selection device according to the present invention, which comprises a feeder chute from which confections are dispensed loose onto a central reception table rotatable about a substantially vertical axis, and made to turn at a prescribed speed; a stationary guide is positioned substantially in contact with a top surface of the central table so as to create a spiral along which the candy is conveyed to a peripheral area affording an exit from the table. The table is encompassed by an orbital selection unit, comprising first conveyor means by which the confections are accelerated loose along a first path, departing from the peripheral exit area and encircling the vertical axis externally of the central table, and second conveyor means, by which the confections are transported singly, spaced apart at equal distance one from the next, along a second path substantially encircling the first path and coinciding with it at a convergence zone, where the confections circulating on the first conveyor means are transferred centrifugally to the second conveyor means.
At least two stations are located in sequence along the path of the second conveyor means, at which regular confections are selected and substandard confections rejected, respectively. Selection is enabled by gaging means located along the second path, and by cam-profile ejection means positioned at the selection station, for removal of regular confections, and at the reject station, for removal of substandard confections; in either case, ultimate ejection of the single confections from the second path occurs by centrifugal force.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which:
FIG. 1 shows a preferred embodiment of the selection device, according to the invention, viewed in perspective from above with certain parts omitted better to reveal others;
FIG. 2 is a plan of the device as in FIG. 1;
FIG. 3 shows a detail of FIG. 1 viewed in perspective from above and on larger scale;
FIGS. 4, 5 and 6 are perspectives of a first detail of FIG. 3, viewed on larger scale and in different operating situations;
FIGS. 7, 8 and 9 are perspectives of further details of FIG. 3, viewed on larger scale and in operation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 of the drawings, 1 denotes a selection device for sweet confections, in its entirety. Such a device operates in conjunction with a feeder comprising a chute 2 from which confections 3 are dispensed, dropping at random onto a substantially horizontal and centrally located reception table 4 supported from beneath by a bearer pedestal 5 with a substantially vertical axis 6. The table 4 will be connected to a drive shaft (not illustrated), extending upwards from the pedestal 5, by which it is rotated at a substantially constant, prescribed speed, in the direction of the arrow denoted 7. The device 1 further comprises an orbital selection unit, denoted 8 in its entirety, affording first conveyor means that consist in a substantially flat second table 9 of annular embodiment, disposed coaxial with and in the same plane as the central table 4, the peripheral inner edge of which lies substantially in contact with the peripheral outer edge of the first table 4. The second table 9 is rotatably supported by the pedestal 5, and will be associated with a conventional transmission (not illustrated), interconnecting the two tables 4 and 9 in such a way that rotation of the first table 4 in the direction of the arrow 7 is accompanied by rotation of the second table 9, moving in the same direction, indicated by the arrow denoted 10, but at a significantly higher speed.
11 denotes a stationary guide located above the central table 4, supported by the pedestal 5 and combining with the top surface of the table 4 to create a voluted channel 12 that extends from the area of the table 4 directly beneath the outlet of the chute 2 around to a peripheral area 13 where the first table 4, hence the channel 12 itself, communicates with the second table 9.
The orbital selection unit 8 further comprises an essentially cylindrical pan 14, the cylindrical wall 15 of which entirely encompasses the tables 4 and 9; the pan is installed on a tilt, its axis 16 canted through a given angle A away from the axis 6 of the pedestal. 17 denotes a hub attached to the bottom of the pan 14, coaxial with its axis 16, which is supported rotatably by the pedestal 5 and affords a pulley 17 around which to loop a drive belt 18 via which the pan is connected to and set in rotation about its own axis 16 by a motor 19; the pan 14 is made to turn, preferably, at a speed matching that of the second table 9, and revolves in the direction indicated by the arrow denoted 20. Thus, the directions denoted by arrows 7, 10 and 20 are similar.
The cylindrical wall 15 of the pan 14 lies with its inner surface substantially in contact with the peripheral outer edge of the second table 9, and terminates uppermost in second conveyor means that consist in a castellated ring 21 disposed coaxial with the axis 16 of the pan 14 and rotatable as one with the pan itself. Given the angle that separates the pan and pedestal axes 16 and 6, the ring 21 is tilted in relation to the second table 9, and the height and position of the pan wall 15 in relation to the table 9 are such that the ring 21 revolves predominantly on a level above that of the table 9; in effect, the paths of the ring 21 and the second table 9 coincide only through a relatively short distance at a convergence zone denoted 22, where a stretch of the internal periphery of the ring 21 lies substantially tangential to a corresponding stretch of the peripheral outer edge of the second table 9.
More exactly, it will be seen from FIG. 1 that the ring 21 is castellated with a plurality of radial sockets 23 distributed uniformly around its topmost surface 24. Each such socket 23 extends outward from the peripheral inner edge of the surface 24, and is of transverse dimensions such as to admit a regular confection 3; of longitudinal dimensions (i.e. radial, in relation to the axis 16) such as to accommodate a regular confection 3 substantially in its entirety; and of depth marginally less than the thickness of a regular confection 3. The single socket 23 is splayed at the side offered inward to the second table 9, and tapered radially toward a gaged external gap 25 the width of which is less than the minimum width of a regular confection 3. The bottom of the socket 23 affords a substantially flat surface 26, which lies essentially within the same plane as the top surface of the second table 9 when the socket 23 passes through the convergence zone 22.
Rotating about the pan axis 16, the ring 21 is made to interact with two cam-profile ejection units 27 and 28 (see FIG. 3) by which regular and substandard confections 3, respectively, are steered from the sockets 23 into two corresponding ducts 29 and 30 positioned alongside the peripheral outer edge of the ring 21; the two ducts are located respectively at a selection station 31 (encountered first, with respect to the direction of rotation arrowed 10), and a final reject station 32.
For selection purposes, substandard confections 3 include those of insufficient depth (thickness), such as the confection denoted 3A in FIG. 5, and those which are either short (radially) or chipped, such as that denoted 3B in FIG. 6.
The ejection unit 27 at the selection station 31 comprises first and second fixed cam plates 33 and 34, of which the first is positioned externally of the socketed ring 21 and the second internally, considered in the radial dimension of the device 1. The first plate 33 consists in a flat deflector, placed in the path of the sockets 23 substantially in contact with the top surface 24 of the ring 21, the inward facing edge 35 of which exhibits an essentially spiral contour angled from the outside inward, in relation to the direction arrowed 10, departing from a point coinciding substantially with the peripheral outer surface of the ring 21 and extending to a point coinciding substantially with the peripheral inner surface of the ring 21. The second plate 34 comprises a first deflector 36, which describes a cylindrical surface coaxial with the ring 21 and terminates uppermost in a helical edge 37 angled upwards in the direction of the arrow 10 from a level immediately below the bottom surface 26 of the sockets 23 to a level immediately above the top surface 24 of the ring. The top end of this first deflector 36 merges ultimately with the leading end of the angled edge 38 of a second deflector 39 that lies parallel with the first cam plate 33 and extends outward, above the ring 21.
In the example of FIG. 3, the first cam plate 33 is advanced to a degree from the second cam plate 34, considered in relation to the rotation arrowed 10, whilst the and section of its contoured edge 35 is positioned substantially in horizontal alignment with the top of the helical edge 37.
The reject ejection unit 28 similarly comprises a cam plate 40, which describes a cylindrical surface coaxial with the ring 21, engages slidably by way of its bottom edge in an annular groove 41 let into the top surface 24, and is of depth at least equal to that of the sockets 23. The plate 40 in question exhibits an upwardly angled edge 42, of which the leading end lies on a level with the groove 41, whilst the trailing edge rises above the level of the top surface 24 of the ring 21.
43 denotes a flipper located at the entry into the convergence zone 22, lying above and substantially parallel with the top surface 24, the inner edge 44 of which exhibits a spiral contour that extends gradually inward in relation to the inner surface of the cylindrical pan wall 15.
45 denotes a fence flanking an intermediate stretch of the convergence zone 22, positioned externally of and parallel with the ring 21, the substantially circular inner edge 46 of which lies tangential to the gaps 25.
Finally, 47 denotes a rotary brush 47 located above the convergence zone 22, which both assists entry of the confections 3 into the sockets 23 and serves to separate or knock out any confections 3 that may have stuck together.
In operation, the sweet confections 3 run down the chute 2 onto the rotating central table 4, dropping into the channel 12, spreading apart initially and then continuing around to the peripheral area 13, where they are transferred to the outer table 9 by centrifugal force. Once on the second table 9, the confections 3 are accelerated strongly as a result of the higher speed of rotation and flung outwards into contact with the cylindrical wall 15 of the pan 14; following expulsion from the channel 12, moreover, this same acceleration produces a further scatter, so that on reaching the pan wall 15, the confections 3 will be arranged substantially in single file.
The confections 3 continue forward in contact with the wall 15 until reaching the convergence zone 22, where some will find their way into the sockets 23; the remainder continue to circulate on the table 9, still in contact with the wall 15, until sockets 23 can be located during successive rotations. As illustrated in FIG. 8, it can happen that certain of the confections 3, which in the example of the drawings are of flat rectangular parallelepiped shape, remain standing "on-edge" following passage to the second table 9; any confection circulating in this position must necessarily encounter the flipper 43 on approaching the convergence zone 22, and accordingly, is made to topple over through 90° and lie flat, thereby enabling its entry into one of the sockets 23.
Again, as illustrated in FIG. 9, it may happen that certain confections 3 locate incorrectly in their sockets 23 and remain skew. In a situation such as this, one corner of the confection 3 will generally project through the gap 25 of the radial socket 23; accordingly, this corner is brought into contact with the fence 45, and the confection 3 is caused to turn around inside the socket 23 until correctly positioned.
Needless to say, where the confections 3 happen to be of shape other than as illustrated and mentioned above, for example spherical, the flipper 43 and the fence 45 can be discarded.
Positioned in the sockets 23, the confections are first conveyed by the revolving ring 21 through an initial reject station 48 immediately following the convergence zone 22, considered in the direction of the arrow 10; here, the effect of centrifugal force expels any dust and powdered matter, or fragments of the confections that may have found their way into the sockets 23, projecting them through the gaps 25 and into a duct 49. The gaps 25 therefore function as initial sizing gages, inasmuch as the radial sockets 23 retain only those confections 3 that present the correct transverse dimensions. Also removed at the initial reject station 48 will be any confections 3 that may have remained stuck together in the socket 23, even after passing under the brush 47; these too are expelled, by centrifugal force.
Continuing their passage around the pan, carried in the sockets 23, the single confections 3 ultimately encounter the ejection unit denoted 27.
As FIG. 4 illustrates, each confection 3 exhibiting regular thickness, hence projecting marginally above the level of the socket 23, will be engaged by the contoured edge 35 of the first cam plate 33, steered radially inward onto the top edge 37 of the first deflector 36, tilted up substantially above the level of the ring 21, and guided into contact with the edge 38 of the second deflector 39. Thus it happens, by a combination of deflection and centrifugal force, that each regular confection 2 finds its way ultimately into the duct 29 of the selection station 31.
As discernable from FIG. 5, a confection 3A of less than the prescribed thickness will be completely encompassed by the socket 23, and therefore cannot be engaged by the first cam plate 33; accordingly, any such confection 3A by-passes the second cam plate 34 altogether.
As illustrated in FIG. 6, a confection may also be of regular thickness and width, but short in the remaining radial dimension; such a confection 3B will be engaged by the first cam plate 33 just the same, but does not project far enough inward from its socket 23 to be lifted by the second plate 34.
Accordingly, any rejects of the type denoted 3A or 3B will pass through the regular ejection unit 27 and remain in their sockets 23 until encountering the upwardly angled edge 42 of the cam plate 40 at the second ejection unit 28, where they are lifted above the level of the sockets 23 to enable final ejection by centrifugal force into the relative duct 30.
As regards the rejection of confections that may exhibit greater than regular thickness, these can either be removed from their sockets 23 naturally, by centrifugal force (where the center of mass is located above the top surface 24 of the ring 21), or alternatively, expelled into the initial reject duct 49 by another ejection unit (not illustrated) located at the relative station 48, which will be similar to the ejection unit denoted 27 in every respect save for the fact that its first plate 33 will not be positioned in contact with the top surface 24 of the rings 21, but elevated from it by a distance corresponding to the maximum permissible thickness of the regular confection 3, minus the depth of the socket 23.
Further to this particular aspect of the invention, it will be observed that, in the event of there being no requirement for thickness control, both the additional ejection unit (not illustrated) and the first cam plate 33 of the selection unit 27 can be dispensed with. In this instance, in fact, it suffices to utilize a socketed ring 21 of annular width marginally less than the prescribed width of the confection (measured radially from the axis 16) and position the first deflector 36 substantially in contact with the peripheral inner edge of the ring 21.
It will be appreciated from the foregoing that, by effecting selection with the confections following a circular path, the dimensions of the device 1 can be reduced considerably. In addition, the device incorporates practically no vibrating parts, and therefore is able to operate at significantly low noise levels. Lastly, by adopting an orbital design in which the two tables 4 and 9 and the ring 21 are kept rotating continuously, one ensures a constant ejection from the device of powdered matter and fragments, and in consequence, a drastic reduction both in the frequency and in the duration of pauses for cleaning and servicing. | 4y
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CROSS REFERENCE TO RELATED APPLICATION
This application is a National Phase Application of International Application No. PCT/CN2009/000077, filed on Jan. 19, 2009, which claims priority to and the benefit of Chinese Patent Application Serial No. 200810004335.5, filed on Jan. 22, 2008. This application claims priority to and the benefit to each of the above two applications, each the disclosure of which is incorporated by reference in its entirety.
FIELD OF THE INVENTION
The present invention in general relates to absorptive heat pump circulation technology in thermal engineering field, in particular, relates to absorptive heat pump system and heating method that carry absorptive heating under the condition of only one set of external driving heat source and output heat of high grade outward, which extensively apply to the utilization of excess heat at a low temperature and also energy-saving and emission-reducing in the process of distillation fractionation, evaporation concentration, materials desiccation, adsorbent regeneration and so on, in the fields of such as chemical industry, food industry, sewage treatment, sea water desalination and so on.
BACKGROUND OF THE INVENTION
With reference to FIG. 1 , current absorptive heat pump circulation system is characterized in utilizing absorption solution can precipitate steam with components of low boiling points under a certain condition, and can intensively absorb steam with components of low boiling points under another condition. The absorptive heat circulation in prior art mostly adopts the absorption solution with two components, often the component of low boiling point is referred as working medium, and the component of high boiling point is referred as absorbent, and the two components form a working medium pair, which is commonly aqua-lithium bromide working medium pair. Current absorptive heat pump circulation system mainly comprises: a generator 11 equipped internally with a heat exchanger 110 , a condenser 12 equipped internally with a heat exchanger 120 , an evaporator 13 equipped internally with a heat exchanger 130 and an absorber 14 equipped internally with a heat exchanger 140 , besides, it further comprises an absorption solution self heat exchanger 150 , an absorption solution pump, a throttler (not shown in the figure) and so on as auxiliary devices. The generator 11 and condenser 12 are connected through steam pipeline 19 , and evaporator 13 and absorber 14 are connected through steam pipeline 18 . The absorption solution circulates between the generator 11 and the absorber 14 through absorption solution pipeline 16 and 15 .
The operation process of the current absorptive heat pump circulation comprises: (1) utilizing driving heat source (for example, water steam, hot water, combustion gas and so on to heat the lithium bromide solution with a specific concentration transferred from the absorber 14 in the generator 11 , and evaporate the water out of the lithium bromide solution, to form the lithium bromide with thicker concentration to circulate into the absorber 14 ; (2) the water steam entering into the condenser 12 through the steam pipeline 19 , and being condensed into to condensation water by the condensing working medium in the heat exchanger 120 ; (3) the condensation water entering into the evaporator 13 through the condensation water pipeline 17 , and feeding the same one or another driving heat source with the heat exchanger 130 , so that the condensation water from the condenser can be converted into water steam; (4) the water steam entering into the generator 14 through the steam pipeline 18 , and being absorbed by the absorption solution from the generator 11 and generates absorption heat, meanwhile the concentration of the absorption solution being reduced, and the absorption solution with thicker concentration circulates into the generator 11 , the absorption heat being used to heat the working medium (generally water) in the heat exchanger 140 , increasing the temperature of the working medium and the heat as heating energy with higher grade than the driving heat source being outputted outward (when the working medium is water, it can be outputted in the form of water steam), to achieve the target that the present absorptive heat pump circulation system outputs heat energy with high grade outward. In the circulation process, the absorption solution from the absorber 14 exchanges heat with the absorption solution from the generator 11 in the absorption solution self heat exchanger 150 .
Apart from the necessity of setting an external driving heat source for evaporating the condensation water in the heat exchanger 130 of the evaporator, the above mentioned current absorption heat pump circulation system, also has to adopt the same one or another external driving heat source to heat the absorption solution, so as to obtain the absorption solution with high concentration. That is to say, the current heat pump circulation system must utilize two external driving heat sources in the generator and the evaporator concurrently, which not only limits the improvement of the heat pump circulation heating coefficient, but also limits the application of the heat pump circulation system in the area in lack of high grade heat source and water source.
SUMMARY
It is the fundamental object of the present invention to overcome the existing problem of the absorptive heat pump circulation system and the heating method, and provide an absorptive heat pump circulation system of self-energized driving heat source and a heating method, and the technical problem to be solved is to operate absorptive heating under the condition of only one external driving heat source, to output heat energy with high grade outward, in order to significantly improve heating coefficient, i.e. energy efficiency, so that it has more practicability and more industry value.
The objective of the present invention and the solution of the technical problems are achieved by the following technical solution. According to the present invention, an absorptive heat pump circulation system comprises: a generator, equipped with a heat exchanger for concentrating absorption solution and outputting steam outward; an evaporator, equipped with a heat exchanger, with which feed driving heat source; an absorber, equipped with a heat exchanger; an absorbent crystallizer, receiving and cooling the absorption solution from the absorber and/or the generator, and forming the absorbent crystals and absorption solution after crystallization, wherein the absorption solution after crystallization is transferred to the generator, and the absorbent crystals is transferred to the absorber; the heat exchanger of the generator and the heat exchanger of the absorber are connected to form a thermal cycling loop, which transfers absorption heat generated by the absorber to the generator.
The objectives of the present invention are further achieved by the following technical solution.
Preferably, the absorptive heat pump circulation system described above further comprises: an absorption solution self heat exchanger, for exchanging heat between the absorption solution from the generator and/or the absorber, and the absorption solution after crystallization and/or the absorbent crystals or the absorption solution containing absorbent crystals.
Preferably, the absorptive heat pump circulation system described above further comprises: an absorption solution self heat exchanger, for exchanging heat between the absorption solution from the absorber and the absorption solution after crystallization from the absorbent crystallizer.
Preferably, the absorptive heat pump circulation system described above further comprises: an absorption solution self heat exchanger, for exchanging heat between the absorption solution from the absorber and the absorbent crystals from the absorbent crystallizer or the absorption solution containing absorbent crystals from the absorbent crystallizer.
Preferably, the absorptive heat pump system described above further comprises: an absorption solution self heat exchanger, for exchanging heat between the absorption solution from the absorber as well as the absorption solution after crystallization from the absorbent crystallizer, and the absorbent crystals or the absorption solution containing absorbent crystals.
Preferably, in the absorptive heat pump system described above, the absorption solution from the absorber and the absorption solution from the absorbent crystallizer are mixed and the mixture enters into the absorption solution self heat exchanger, and then exchanges heat with the absorption solution after crystallization from the absorbent crystallizer and the absorbent crystals or the absorption solution containing absorbent crystals.
Preferably, in the absorptive heat pump system described above, the heat cycling loop is provided with an external heat source heating device, for compensating the insufficient part of the heating capacity of the generator caused by the heat-dissipating loss.
Preferably, the absorptive heat pump circulating system further comprises water source, for providing water for the evaporator.
Preferably, the absorptive heat pump system further comprises: a compression refrigeration subsystem constituted of absorbent crystallizer-evaporator, compressor, absorption solution heat exchanger-condenser, throttle valve and compression refrigeration working medium pipeline, for providing cooling capacity for the absorbent crystallizer.
The objective of the present invention and the solution of the problem are achieved by the following technical solution. According to the present invention, an absorptive heating method comprises the following steps:
(1) concentrating the absorption solution in a generator and meanwhile generating steam, and then outputting the steam outward, transferring the concentrated absorption solution to an absorber;
(2) utilizing driving heat source to heat absorption solution in the evaporator, and the generated steam being led into the absorber;
(3) the absorption solution absorbing the steam from the evaporator in the absorber and generating absorption heat, and meanwhile the concentration of the absorption solution being decreased and the absorption solution being transferred to the absorbent crystallizer;
(4) performing cooling, crystallizing and liquid-solid separating for the absorption solution in the absorbent crystallizer, forming absorbent crystals and absorption solution after crystallization, the absorption solution after crystallization being transferred to the generator, and the absorbent crystal and the absorption solution containing absorbent crystals being transferred to the absorber;
(5) performing heat circulation between the absorber and the generator, the absorption heat generated when the absorption solution absorbs the steam in the absorber is transferred to the generator.
Preferably, the method for absorptive heating described above further comprises, before the absorption solution after crystallization being transferred to the generator and before the absorption solution outputted by the absorber being cooled, the absorption solution output by the absorber exchanges heat with the absorption solution after crystallization.
Preferably, the method for absorptive heating described above further comprises, before the absorbent crystal being transferred to the absorber and before the absorption solution outputted by the absorber being cooled, the absorbent crystals or the absorption solution containing absorbent crystals exchanges heat with the absorption solution outputted by the absorber.
Preferably, the method for absorptive heating described above further comprises, before the absorption solution after crystallization being transferred to the generator, the absorbent crystal being outputted to the absorber and the absorption solution outputted by the absorber being cooled, the absorption solution outputted by the absorber exchanges heat with the absorbent crystals as well as the absorption solution after crystallization.
Preferably, the method for absorptive heating described above further comprises, before the absorption solution after crystallization being transferred to the generator, the absorbent crystal being transferred to the absorber and before the absorption solution outputted by the absorber being cooled, the absorption solution outputted by the generator and the absorption solution outputted by the absorber are mixed to form a mixed absorption solution, the mixed absorption solution exchanges heat with the absorbent crystals as well as the absorption solution after crystallization.
Preferably, the method for absorptive heating described above further comprises, in the heat circulation process of step (5), the insufficient heating part of the heating capacity of the generator is compensated through external heat source.
Preferably, for the method for absorptive heating described above, the temperature of the driving heat source after utilization is no lower than 2° C.
Preferably, for the method for absorptive heating described above, the cooling capacity required for cooling and crystallizing the absorption solution in step (4) is provided by compression refrigeration circulation.
Preferably, for the method for absorptive heating described above, the compression refrigeration circulation comprises:
compressing the refrigeration working medium, to increase the pressure and temperature of the refrigeration working medium;
the refrigeration working medium with increased temperature exchanges heat with the absorption solution after crystallization from the absorbent crystallizer and/or absorbent crystals or absorption solution containing absorbent crystals;
after being dilated, the refrigeration working medium after heat exchanging absorbing heat from the absorbent crystallizer.
Preferably, for the method for absorptive heating described above, the temperature of cooling and crystallizing the absorption solution in step (4) is −15˜60° C.
The driving heat source in the technical solution described above can utilize the excess heat at a low temperature of great volume and difficult to utilize in the high-energy consumption industry, such as steel industry, building material industry and chemistry industry.
Compared with current technology, the present invention possesses obvious advantage and beneficial effects. According to the above technical solution, because of an absorbent crystallizer and the heating energy generated by the absorber being provided to the generator directly through the heat cycling loop, the absorptive heat pump circulation systems and heating method of the present invention therefore can basically omit the external driving heat source required by the generator in the current absorptive heating circulation system to realize absorptive heating, so that the coefficient of performance (COP) is improved and the temperature of the driving heat source required, i.e. the temperature of the available excess heat at a low temperature, is significantly decreased, so as to be more practical.
Besides, since the absorptive heat pump system of the present invention needs no setting of a condenser, therefore, different from the current absorption heat pump circulation, the present invention does not adopt condensation water to cool down the condenser, so that the operational load of the cooling tower can be largely reduced, meanwhile the water resource is saved.
The preferred embodiments and detailed description with the accompanying drawings are set forth in this invention as below, to fully understand the technical solution of this invention and thereafter implement the solution according to the description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a flow chart of an absorptive heat pump circulation system in prior art.
FIG. 2 illustrates a flow chart of an absorptive heat pump circulation system according to the first embodiment of the present invention.
FIG. 3 illustrates a flow chart of an absorptive heat pump circulation system according to the second embodiment of the present invention.
FIG. 4 illustrates a flow chart of an absorptive heat pump circulation system according to the third embodiment of the present invention.
FIG. 5 illustrates a flow chart of an absorptive heat pump circulation system according to the fourth embodiment of the present invention.
FIG. 6 illustrates a flow chart of an absorptive heat pump circulation system according to the fifth embodiment of the present invention.
11:
generator
12:
condenser
13:
evaporator
14:
absorber
17:
condensation water pipeline
18 and 19:
steam passage
15, 16, 20 and 30:
absorption solution pipeline
40:
pipeline for absorption solution after crystallization
50:
pipeline for solution containing crystals
60:
working medium pipeline for heat circulation
110, 120, 130 and
heat exchanger
140:
141:
absorbent crystallizer
142:
mixer
150:
absorption self heat exchanger
160:
heating device for external heat source
200:
absorbent crystallizer-evaporator
210:
compressor
220:
absorbent heat exchanger-condenser
230:
throttle valve
240:
compression refrigeration working medium pipeline
DETAILED DESCRIPTION
Various aspects are now described with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the absorption heat pump system and its specific embodiment, structure, feature and functions.
With reference to FIG. 2 , a flow chart of the absorption heat pump circulation system according to the first embodiment of the present invention is illustrated, the absorptive heat pump circulation system, mainly comprises: a generator 11 , an evaporator 13 , an absorber 14 and water source 200 , and absorption solution utilizing aqua-lithium bromide working medium pair. The generator 11 is configured to concentrate absorption solution, which is provided with a heat exchanger 110 therein, feed the heat circulation working medium from the heat exchanger 140 in the absorber 14 with the heat exchanger 110 , to heat the lithium bromide as the absorption solution to evaporate the water therein, so that the concentration of the absorption solution is increased, and the high temperature steam generated thereby is outputted through the steam passage 19 , as so as to be further utilized by the users. The absorption solution in the outlet of the absorber 11 enters into the generator 14 through the absorption solution pipeline 20 , and the absorption solution in the outlet of the generator 14 enters into the generator 11 through the absorption solution pipeline 30 . The absorption solution is circulated between the generator 11 and the absorber 14 through the absorption solution pipelines 20 and 30 . The heat pump evaporator 13 is provided with a heat exchanger 130 , feed the driving heat source with the heat exchanger 130 to convert the water from the water source into steam, the generated steam is led into the absorber 14 via the steam passage 18 . The absorber 14 is provided with a heat exchanger 140 , and in the absorber 14 , the absorption solution of high concentration from the generator 11 absorbs the steam from the evaporator 13 and generates the absorption heat, so that the temperature of the heat circulation working medium in the heat exchanger 140 is increased. The heat exchanger 140 and the heat exchanger 110 in the generator 11 are connected by heat circulation working medium pipeline 60 to form a heat cycling loop, so as to provide the absorption heat generated by the absorber 14 to the generator 11 as the driving heat of the generator. In the present embodiment, the heat cycling loop is a heat pipe cycling loop, at the moment, the installation position of the generator 11 is higher than that of the absorber 14 . Regarding the heat pipe cycling, the working medium in the heat pipe can form convection by the process of condensing-evaporating without external driving force, so as to circulate between the absorber and the generator and transfer heat. The heat cycling loop is provided with a heating device 160 with external heat source, for compensating the insufficient part of the heat of the generator caused by radiation loss.
According to the first embodiment of the present invention, the absorptive heat pump system is further provided with an absorbent solution heat exchanger 150 , absorbent crystallizer 141 and mixer 142 between the absorber 14 and the generator 11 . The absorbent crystallizer 141 has an input for absorption solution, an output for absorption solution after crystallization and an output for absorbent crystals. The input for absorption solution of the absorbent crystallizer connects to the outlet for absorption solution of the absorber 14 through the absorption self heat exchanger 150 , the crystallization outlet for the absorption solution in the absorbent crystallizer connects to the inlet for the absorption solution of the generator 11 , and the crystallization outlet for the absorption solution connects to the inlet for the absorption solution of the generator through the mixer 142 in the case that the mixer 142 exists. The outlet for the absorption solution of the generator 11 enters into the absorber 14 through the absorption solution pipeline 20 via the mixer 142 , and outlet for the absorption solution of the absorber 14 enters into the absorbent crystallizer 141 through the absorption solution pipeline 30 via absorption solution self heat exchanger 150 . In the absorbent crystallizer 141 , the low temperature cooling capacity is utilized to cool and crystallize the absorption solution, because crystals generate if aqueous solution of lithium bromide reaches or approaches crystallization point, the lower the crystallization temperature is, the lower the equilibrium concentration of liquid-phase lithium bromide is, therefore, through cooling and crystallizing, however high the concentration of the lithium bromide the absorption solution before cooling and crystallizing, and after crystallization the concentration of the lithium bromide can reach or approach to the equilibrium concentration of liquid-phase lithium bromide at the cooling temperature. After crystallization and solid-liquid separation, the absorption solution after the crystallization in absorbent crystallizer 141 , i.e., dilute solution of lithium bromide, is transferred to the generator 11 through the absorption solution pipeline 30 via the absorption solution heat exchanger 150 . The cool source employed by the absorbent crystallizer 141 described above can be cooling water of 0-32° C. The water source 200 can be domestic water or industrial water, or the condensation water formed after the high temperature steam output by the generator 11 is utilized; if other working medium is employed as the working medium of the absorption solution, then the water source 200 can also provide corresponding liquid-phase working medium. The absorptive heating device of the present embodiment only needs driving heat source provided in the evaporator 13 , i.e., high temperature steam can be obtained in the steam pipeline 19 of the generator 11 .
The absorption solution in the absorbent crystallizer 141 can form absorbent crystals and absorption solution after crystallization. The absorbent crystal mentioned in the present embodiment and the following embodiments are not only limited to adopt absorbent crystals particles, but also absorption solution containing absorbent crystals particles. There are other relationships among absorber 14 , generator 11 , absorption solution self heat exchanger 150 and absorbent crystallizer 141 as described hereinafter.
With reference to FIG. 3 , a flow chart of the second embodiment according to the present invention is illustrated. The absorption solution self heat exchanger 150 is configured to exchange heat between the absorption solution from the absorber 14 and the absorbent crystals (the absorption solution containing the absorbent crystals) outputted from the absorbent crystallizer 141 . The outlet for the absorption solution pipeline 20 of the generator 11 connects with the inlet for the absorption solution pipeline of the absorber, so that the absorption solution outputted from the generator 11 is mixed with the absorbent crystals after heat exchanging and then inputted into the absorber together. The absorption solution after crystallization from the absorbent crystallizer 141 is outputted to the generator 11 via the inlet for the absorption solution pipeline 30 . After heat exchanging, the absorption solution from the absorber 14 is delivered into the absorbent crystallizer 141 to carry on cooling, crystallizing and liquid-solid separating; after heat exchanging, the absorbent crystal from the absorbent crystallizer 141 is delivered into the absorber 14 via the inlet for the absorption solution pipeline. Because the temperature of the absorption solution from the absorber 14 is much higher than that of the absorbent crystal outputted from the absorbent crystallizer 141 , after heat exchanging, the temperature of the absorption solution entering into the absorbent crystallizer 141 significantly decreases, so as to decrease the cooling capacity for cooling the absorption solution. Meanwhile, the temperature of the absorbent crystals from the absorbent crystallizer after heat exchanging is greatly increased, and the absorbent crystals from the absorbent crystallizer is transferred to the absorber to absorb the working medium steam of the same quantity, and release absorption heat in higher operation temperature, so as to increase the temperature that the absorber outputs outward, improve the heat grade and enhance power utilization efficiency.
With reference to FIG. 4 , a flow chart of the third embodiment according to the present invention is illustrated. After crystallization, the solution outputted from the absorbent crystallizer 141 also pass through absorption solution self heat exchanger 150 , and the solution from the absorber 14 exchanges heat with the absorbent crystals outputted from the absorbent crystallizer 141 (or the absorption solution containing the absorbent crystals) as well as the absorption solution after crystallization concurrently. After heat exchanging, the absorption solution after crystallization is delivered to the generator 11 via absorption solution input pipeline 30 . The absorption solution output pipeline 20 of the generator 11 is connected with the absorption solution input pipeline of the absorber, so as to mix the absorption solution outputted from the generator 11 and the absorbent crystals after heat exchanging and deliver the mixture into the absorber together. The absorption solution after crystallization from the absorbent crystallizer 141 is delivered to the generator 11 via the absorption solution input pipeline 30 . After heat exchanging, the absorption solution from the absorber 14 is delivered into the absorbent crystallizer 141 to carry on cooling, crystallizing and liquid-solid separating; after heat exchanging, the absorbent crystals from the absorbent crystallizer 141 is delivered into the absorber 14 via absorption solution input pipeline. Because the temperature of the absorption solution from the absorber 14 is far higher than the temperature of the absorbent crystals outputted from the absorbent crystallizer 141 as well as the absorption solution after crystallization, after heat exchanging, the temperature of the absorption solution entering into the absorbent crystallizer 141 is significantly decreased, so as to decrease the cooling capacity for cooling the absorption solution. Meanwhile, after heat exchanging, the temperature of the absorbent crystals from the absorbent crystallizer is greatly increased, and the absorbent crystals from the absorbent crystallizer is transferred to the absorber to absorb the working medium steam of the same quantity, and release absorption heat in higher operation temperature, so as to increase the temperature that the absorber outputs outward and improve the heat grade. After heat exchanging, the temperature of the solution after the crystallization from the absorbent crystallizer is significantly increased, and the solution after the crystallization from the absorbent crystallizer is transferred to the generator, to evaporate the same working medium steam, and in the present embodiment the heat consumed by the generator can be reduced, so as to enhance power utilization efficiency.
With reference to FIG. 5 , a flow chart of the fourth embodiment of the present invention is illustrated. The absorption solution output pipeline 20 of the generator 11 is connected with the absorption solution output pipeline 30 of the absorber 14 , and the joint is located before the absorption solution self heat exchanger 150 . The absorption solution from the generator 11 and the absorption solution from the absorber 14 are mixed and then the mixture enters into the absorption solution self heat exchanger 150 , to concurrently exchange heat with the absorbent crystals and the absorption solution after crystallization outputted from the absorption crystallizer 141 . After heat exchanging, the absorption solution after crystallization is transferred to the generator 11 via the absorption solution input pipeline. After heat exchanging, the absorbent crystals is transferred to absorber 14 via the absorption solution input pipeline. Compared with the previous method, the method that the absorption solution from the generator 11 and the absorption solution from the absorber 14 are mixed and then carry on cooling and crystallizing increases the quantity of the absorption solution being cooled and crystallized, so as to obtain more absorption solution crystallized, so that the utilization efficiency of the absorbent crystallizer is enhanced.
With reference to FIG. 6 , a flow chart of the fifth embodiment according to the present embodiment. The absorptive heat pump circulation is essentially the same as the previous embodiment, and the difference lies in that, it further comprises a compression refrigeration circulation subsystem, for providing cooling capacity at a low temperature for the absorbent crystallizer 141 . The compression refrigeration circulation subsystem comprises: absorbent crystallizer-evaporator 200 , compressor 210 , absorption solution heat exchanger-condenser 220 , throttle valve 230 and compression refrigeration working medium pipeline 240 . After compression refrigeration working medium is condensed in the heat exchanger-condenser 220 , it is evaporated in the absorbent crystallizer-evaporator 200 through throttle valve 230 , so as to provide cooling capacity at a low temperature for the absorbent crystallizer 141 . The steam of the compression refrigeration working medium in the outlet of the absorbent crystallizer-evaporator 200 is compressed by the compressor 210 and then enters into the absorption solution heat exchanger-condenser 220 , so as to accomplish the compression refrigeration circulation. The absorbent crystallizer-evaporator 200 can be a component of the absorbent crystallizer 141 .
Since part of the crystals in the absorbent (lithium bromide) extracts, the concentration of the absorbent solution crystallized after liquid-solid separation in the absorbent crystallizer 141 is decreased. After the crystallization, the absorbent solution, i.e. lithium bromide dilute solution, is inducted to the generator 11 via the absorption solution crystallization pipeline 50 and thereafter the absorption solution heat exchanger-condenser 220 and the absorption solution self heat exchanger 150 . On the other hand, the absorbent crystals and the absorption solution containing absorbent crystals after liquid-solid separation in the absorbent crystallizer 141 is inducted to the mixer 142 via pipeline 40 containing crystallization solution and thereafter the absorption solution self heat exchanger-condenser 220 and the absorption solution self heat exchanger 150 . The function of the absorption solution self heat exchanger 150 lies on heat exchanging for the absorption solution at a high temperature from the absorber 14 and the absorption solution after crystallization and the absorbent crystals or the absorption solution containing the absorbent crystals at a low temperature from the absorbent crystallizer, so as to increase the solution temperature provided to the generator 11 and the mixer 142 , and meanwhile decrease the temperature of the absorption solution provided to the absorbent crystallizer. The function of the absorption solution heat exchanger-condenser 220 lies on heat exchanging for the compression refrigeration working medium steam at a high temperature from the compressor 210 of the compression refrigeration circulation subsystem and the absorption solution after crystallization and the absorbent crystals or the absorption solution containing the absorbent crystals at a low temperature from the absorbent crystallizer 141 , so as to condense the refrigeration working medium steam, and meanwhile completely or partially melt the absorbent crystals and increase the temperature of the absorption solution. Through the condense in the generator 11 , the absorption solution in the outlet for the generator 11 with increased concentration of absorbent is inducted into the mixer 142 to mix with the absorbent crystals (or the absorption solution containing absorbent crystals) through the absorption solution pipeline 20 , and then the mixture is inducted into the absorber 14 together. The present invention can set and optimize the absorbent operation concentration of the absorption solution in the absorber 14 and generator 11 separately. That is to say, the present invention can realize an extremely advantageous technological condition for absorption refrigeration circulation, i.e., while the absorber is operating under the condition of high absorbent concentration, the generator is operating under the condition of the absorbent concentration lower than that of the absorber, which is difficult for the traditional absorptive heat pump circulation. Since the absorbent crystallizer 141 is provided, and the heat generated by the absorber 14 is provided for the generator 11 directly through thermal cycling loop, so as to basically save the external driving heat source for providing heat for the generator 11 in the current absorptive heat pump circulation, and realize the absorptive heating process with self-contained driving heat source.
The sixth embodiment of the present invention provides absorptive heating method, which employs the absorptive heat pump circulation system of the embodiments described above, the refrigeration method comprises the following steps:
(1) Condensing the absorption solution in the generator and meanwhile generating steam, and then delivering the steam to the users, and the concentrated absorption solution being outputted;
(2) Employing driving heat source to heat the absorption solution in the evaporator, and introducing the generated steam into an absorber;
(3) In the absorber, the absorption solution from the generator absorbing the steam from the evaporator and generating absorption heat, and meanwhile the concentration of the absorption solution being decreased and delivering to an absorbent crystallizer;
(4) In the absorbent crystallizer, carrying on cooling, crystallizing and liquid-solid separating for the absorption solution, forming absorbent crystals and absorption solution after crystallization, the absorption solution after crystallization being transferred to the generator, and the absorbent crystals and the absorption solution containing absorbent crystals being transferred to the absorber;
(5) Carrying on heat exchanging between the absorber and the generator, i.e. the absorption heat generated when the absorption solution absorbs the steam in the absorber is transferred to the generator. In particular, the heat exchanger in the absorber and the heat exchanger in the generator are connected to form a thermal cycling loop, and the working medium (commonly water) in the thermal cycling loop absorbs the absorption heat in the absorber and transfers it into the generator, releases the heat in the generator and then returns to the absorber.
The water in the evaporator can be from independent water source or condensation water formed after the steam outputted by the generator is utilized.
Preferably, before the absorption solution crystallized being outputted to the generator and the absorption solution outputted by the absorber being cooled, the absorption solution after crystallization and the absorption solution outputted by the absorber exchange heat.
Preferably, before the absorbent crystal being output to the absorber and the absorption solution output by the absorber being cooled, the absorbent crystal and the absorption solution output by the absorber are heat exchanging.
Preferably, before the absorption solution crystallized being outputted to the generator, the absorbent crystals being outputted to the absorber and the absorption solution outputted by the absorber being cooled, the absorption solution outputted by the absorber and the absorbent crystals as well as the absorption solution after crystallization are heat exchanging.
Preferably, before the absorption solution crystallized being outputted to the generator, the absorbent crystals being outputted to the absorber and the absorption solution outputted by the absorber being cooled, the absorption solution outputted by the generator and the absorption solution outputted by the absorber are mixed to form a mixed absorption solution, the mixed absorption solution and the absorbent crystals as well as the absorption solution after crystallization exchange heat.
Through cooling and crystallizing for the absorbent, the absorption from the generator and/or the absorber and the absorption solution after crystallization and/or the absorbent crystals outputted from the absorbent crystallize exchanges heat, one of whose effects lies in that, only minor external cooling capacity and heating capacity are utilized to maintain the absorbent operation concentration of the absorption solution in the generator relatively low, and meanwhile significantly increase the absorbent operation concentration of the absorption solution in the absorber, so that the absorption heat at a higher temperature is obtained in the absorber, and the absorption heat can be utilized as driving heat source of the generator.
Since an absorbent crystallization process is involved in the method described above, in the case of maintaining the absorbent operation concentration of the absorption solution in the generator relatively low, the absorbent operation concentration of the absorption solution in the absorber is significantly increases meanwhile, so that the absorption heat at a higher temperature is obtained in the absorber, and the absorption heat can be utilized as driving heat source of the generator and raise the operation temperature of the generator, i.e., produce working medium steam with a higher temperature.
Preferably, heat compensation is provided for the thermal cycling process described above, i.e. an external heat source heating device is set to compensate thermal deficiency of the generator heating capacity caused by the dissipation loss, so as to ensure the heating process to keep operating.
The steps in the present embodiment are carrying concurrently without specific sequence in the operation, and all the steps constitute the absorptive heating method together.
The seventh embodiment according to the present invention provides another absorptive heating method, and the absorptive heating method is essentially the same as the previous embodiment, and the difference lies in that, the low temperature cooling capacity required by the cooling and crystallizing of the absorption solution in the absorbent crystallizer comes from compression refrigeration circulation process. The steam of the compression refrigeration working medium in the outlet for the absorbent crystallizer-evaporator 200 enters into the absorption solution heat exchanger-condenser 220 to be condensed after being compressed by the compressor 210 , and the compression refrigeration working medium is evaporated in the absorbent crystallizer-evaporator 200 after passing through the throttle valve 230 , so as to accomplish the compression refrigeration circulation. Since according to the present invention, when the compression refrigeration working medium is condensed in the absorption solution heat exchanger-condenser 220 , the cooling capacity comes from the cooling capacity of the solution in the outlet for the lithium bromide crystallizer 141 , therefore the evaporation temperature and the condensation temperature of the present circulation are relatively close, so as to reach higher refrigeration performance coefficient. In another words, the power consumption of the compression refrigeration circulation according to the present invention is relatively low.
The technical solution of the embodiment described above has no specific constrain over the absorption solution types utilized, and all takes working medium of aqua-lithium bromide as the absorption solution for sample explanation, in the other embodiments, the working medium can be one of or a mixture of several ones of water, methanol and ethanol; absorbent can be one of or a mixture of LiBr, LiCl, LiNO 3 , NaBr, KBr, CaCl 2 , MgBr 2 and ZnCl 2 .
The applicability of the embodiments described above is demonstrated by the following embodiments with specific parameters.
Embodiment 1
Employing the method of the sixth embodiment described, the present embodiment utilizes hot water of 100° C. as the driving heat source of the evaporator, and applies saturated steam of 195° C. as the external heat source to heat the working medium in the thermal cycling loop, so as to compensate the thermal deficiency part of the heating capacity for the driving heat source of the generator caused by dissipation loss, utilizes dimethyl silicon oil as thermal cycling working medium, and utilizes cooling water of 20° C. to cool the absorbent crystallizer 141 . In the present embodiment, the temperature outputted outward is 182° C., the pressure of the superheated vapor is 170 kPa, and coefficient of performance (COP) is 10.0. The COP of the present embodiment is calculated according to the following function:
COP=heating capacity outputted/heat capacity of external heating source employed
Embodiment 2
Employing the method of the sixth embodiment described, the present embodiment utilizes hot water of 100° C. as the driving heat source of the evaporator, and applies saturated steam of 195° C. as the external heat source to heat the working medium in the thermal cycling loop, so as to compensate the thermal deficiency part of the heating capacity for the driving heat source of the generator caused by dissipation loss, utilizes dimethyl silicon oil as thermal cycling working medium, and utilizes cooling water of 60° C. to cool the absorbent crystallizer 141 . In the present embodiment, the temperature outputted outward is 182° C., the pressure of the superheated vapor is 170 kPa, and coefficient of performance (COP) is 10.0. The COP of the present embodiment is calculated according to the following function:
COP=heating capacity outputted/heat capacity of external heating resource employed
Embodiment 3
Employing the method of the seventh embodiment described, the present embodiment utilizes hot water of 80° C. as the driving heat source of the evaporator, and applies saturated steam of 160° C. as the external heat source to heat the working medium in the thermal cycling loop, so as to compensate the thermal deficiency part of the heating capacity for the driving heat source of the generator caused by dissipation loss, applies dimethyl silicon oil as thermal cycling working medium, and utilizes cooling water of −18° C. to cool absorbent crystallizer 141 . In the present embodiment, the temperature outputted outward is 148° C., the pressure of the superheated vapor is 95 kPa, and coefficient of performance (COP) is 5.5. The COP of the present embodiment is calculated according to the following function:
COP=heating capacity outputted/(heat capacity of external heating source employed+power consumption of compressor*3.0)
Wherein, the primary energy generating efficiency of the grid user end for powering the compressor is taken as 33.3%.
Embodiment 4
Employing the method of the fourth embodiment described, the present embodiment utilizes hot water of 7° C. as the driving heat source of the evaporator, and utilizes hot water of 50° C. as the external heat source to heat the working medium in the thermal cycling loop, so as to compensate the thermal deficiency part of the heating capacity for the driving heat source of the generator caused by dissipation loss, utilizes non-freezing solution as thermal cycling working medium, and utilizes cooling water of −18° C. to cool absorbent crystallizer 141 . In the present embodiment, the temperature outputted outward is 37° C., the pressure of the superheated vapor is 0.8 kPa, and coefficient of performance (COP) is 5.0. It can be seen from the present embodiment that the heat energy at a high temperature is provided outward via the generator. Meanwhile the cool capacity at a low temperature is provided outward via the evaporator. The COP of the present embodiment is calculated according to the following function:
COP=heating capacity outputted/(heat capacity of external heating source employed+power consumption of compressor*3.0)
Wherein, the primary energy generating efficiency of the grid user end for powering the compressor is taken as 33.3%.
The following table 1 illustrates the operation parameters and performance of the embodiments described above.
TABLE 1
Embodiment 1
Embodiment 2
Embodiment 3
Embodiment 4
Generator
Temperature of
189.4
189.4
155.4
44.4
Thermal
Cycling
Working
Medium In Inlet
For Heat
Exchanger (° C.)
Temperature of
185.0
185.0
151.0
40.0
Thermal
Cycling
Working
Medium In
Outlet For Heat
Exchanger (° C.)
Lithium
60
66
56
56
Bromide
Concentration In
Inlet (wt %)
Lithium
63
69
59
58
Bromide
Concentration In
Outlet (wt %)
Pressure of
170
100
95
0.8
Outputted
Superheated
Vapor (kPa)
Pressure of
182
182
148
37
Outputted
Superheated
Vapor (° C.)
Evaporator
Temperature
100
100
80
7
Before Driving
Heat Source
Being Utilized
(° C.)
Temperature
95
95
75
2
After Driving
Heat Source
Being Utilized
(° C.)
Pressure (kPa)
81.5
81.5
36.1
0.6
Absorber
Temperature of
185.0
185.0
151.0
40.0
Thermal
Cycling
Working
Medium In Inlet
For Heat
Exchanger (° C.)
Temperature of
189.0
189.0
155.0
44.0
Thermal
Cycling
Working
Medium In
Outlet For Heat
Exchanger (° C.)
Lithium
75
75
75
66
Bromide
Concentration In
Inlet (wt %)
Lithium
72
72
72
64
Bromide
Concentration In
Outlet (wt %)
Pressure (kPa)
81.4
81.4
36.0
0.5
Absorbent
Absorbent
20
60
−18
−18
Crystallizer
Crystallizer—
Evaporator
Temperature
(° C.)
External Heat
Temperature of
189.0
189.0
155.0
44.0
Resource
Thermal
Heating
Cycling
Device
Working
Medium In Inlet
(° C.)
Temperature of
189.4
189.4
155.4
44.4
Thermal
Cycling
Working
Medium In
Outlet
(° C.)
COP
10.0
10.0
5.5
5.0
While the foregoing disclosure discusses illustrative aspects and/or aspects, it should be noted that various changes and modifications could be made herein without departing from the scope of the described aspects and/or aspects as defined by the appended claims. Furthermore, although elements of the described aspects and/or aspects may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. Additionally, all or a portion of any aspect and/or aspect may be utilized with all or a portion of any other aspect and/or aspect, unless stated otherwise.
INDUSTRIAL APPLICATION
Because the absorption heat pump circulation systems and heating methods according to the present invention possesses an absorbent crystallizer, and the heat generated by the absorber is directly provided to the generator through thermal cycling, so as to basically save an external driving heat source required by the generator of the traditional absorptive heating circulation and realize absorption heating, to significantly increase Coefficient of Performance (COP) and significantly decrease the required temperature of the driving heat source, i.e. the temperature of the excess heat at a low temperature that can be utilized, so that it will be more applicable. Besides, since it is not necessary to provide condenser for the absorptive heat pump system according to the present invention, therefore different from the traditional absorptive heat pump circulation, in the present invention cooling water is not utilized to cool the condenser, so that the operation load of cooling tower is significantly relieved and water source is saved meanwhile. | 4y
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for coating a photo-resist film on the surface of a substrate and/or, for developing the photo-resist film subsequent to being exposed with a predetermined pattern, which is used in the manufacture of a semiconductor device, such as an integrated circuit. In particular, the apparatus of the invention is effectively used in manufacturing various types of ASICs with small production in each type.
2. Description of the Related Art
In the manufacture of a semiconductor device, such as an integrated circuit (IC), numerous steps for microfabrication are performed to form a device, such as a transistor, in a wafer of, for example, a silicon single crystal. Of these steps, a photoengraving process (PEP) is of greater importance because of PEP provides the base of a present microfabrication technique. In the PEP, a predetermined resist pattern is formed on the surface of the wafer, the resist pattern being employed as, for example, an etching mask.
The formation of the resist pattern by the PEP comprises the steps of coating a photo-resist on the wafer surface to provide a photo-resist film of uniform thickness, selectively exposing the photo-resist film at a predetermined area and developing the exposed photo-resist film to form a desired pattern. In this exposing step, use is made of an exposing device, such as a step and repeat aligner (that is, a stepper). On the other hand, the step for forming the photo-resist film on the substrate surface is carried out with, for example, an apparatus as will be explained below in more detail.
FIG. 1 is a flowchart showing the processing steps of a photo-resist film formation apparatus called a track system, including treating units carrying out a preheating step 4, cooling step 5, coating step 6 and heating step 8. Semiconductor wafers 1 are introduced into the aforementioned apparatus such that each is held within a cassette-like container 2. The semiconductor wafers 1 are taken out of the cassette 2 sheet by sheet and conveyed by a belt conveying mechanism 3 sequentially to the respective units for performing the respective treatment to be carried out there. At the preheating step 4, the wafer 1 has its moisture removed by heating and, subsequent to being cooled by the cooling step 5, is conveyed to the coating unit where a photo-resist is evenly coated on the surface of the wafer 1 by means of, for example, a spinner coater. The photo-resist-coated wafer 1 is sent to the heating unit 8 having a conveyor mechanism 7 called a walking beam system. At the heating unit 8, the photo-resist solution on the wafer is converted into a stable film. At the completion of the heating step 8, a wafer 9 with a desired photo-resist thin film formed thereon is conveyed into cassette 10 where it is stored as a "treated" wafer.
As set out above, in the conventional apparatus, the respective independent treating units are installed in a serial array and a semiconductor wafer to be treated has to be conveyed inevitably past all these units in a "one-way" course in a predetermined order whether all these treatment is required or not. It is, therefore, not possible to freely change a "once-set" treating order or to cause the wafer to pass selectively through only a predetermined unit or units.
The treating process necessary for forming an IC in the semiconductor wafer 1, including its treating sequence, differs depending upon the kinds of IC's to be formed on the wafer. In spite of some step or steps being unnecessary, it is unavoidable in the conventional apparatus that all the aforementioned steps have to be carried out on the semiconductor wafer. This cause a bar to the implementation of improved throughput.
Under this situation, there has been a growing demand for an apparatus which can freely select any particular treating unit or units and can freely change the order for passing through the units in accordance with the kinds of wafers to be treated.
SUMMARY OF THE INVENTION
It is accordingly the object of the present invention to provide an apparatus having all treating units necessary to form a photo-resist film on a wafer surface and/or develop it subsequent to being exposed with a predetermined pattern, in which the wafer can selectively be treated in any specific treatment order at any specific unit or units in accordance with the kinds of the wafers to be treated.
In order to achieve the aforementioned object, an apparatus for forming a photo-resist film on a semiconductor wafer surface and/or for developing the photo-resist film subsequent to being exposed with a predetermined pattern comprises:
a passage provided in such a manner that it extends in a predetermined direction to allow conveying of a substrate having a surface on which a photo-resist film is to be formed or a substrate having a photo-resist film to be developed;
a plurality of treating units necessary for forming a photo-resist film and/or a plurality of treating units necessary for developing the photoresist film, these units being provided along the passage;
conveying means movable along a predetermined course for conveying the substrate in a predetermined direction;
substrate handling means provided on the conveying means for holding a substrate and for setting a substrate which is held thereon into the treating unit, said substrate handling means being movable and rotatable in any direction; and
control means for selecting said plurality of treating units in any combination and for controlling operations of the conveying means and substrate handling means so that the substrate undergoes predetermined treatments at the selected units in any sequence.
According to the present invention it is preferable to provide a plurality of substrate handling means.
It is also preferable to locate said plurality of treating units in a face-to-face relation across and along the passage for conveying the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing a conventional apparatus a photo-resist film;
FIG. 2 is a plan view showing an apparatus according to an embodiment of the present invention;
FIGS. 3 and 4A to 4C show a pair of tweezers used in the embodiment of the present invention;
FIG. 5 shows an interface mechanism as used in the embodiment of the present invention;
FIG. 6 is a view showing a cassette suitably employed in the embodiment of the present invention; and
FIG. 7 is a plane view showing an apparatus according to another embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 2 shows a plan view showing an apparatus 100 according to an embodiment of the present invention which is adapted to apply a photo-resist film on a semiconductor wafer surface and/or to develop the photoresist film subsequent to being exposed with a specific pattern. In FIG. 2, reference numeral 101 shows a body base of the apparatus. A passage 102 is provided at the middle of the body base 101 and extends in a lateral direction as indicated by an arrow Y in FIG. 2. On one side of the passage 102 are provided a preheating station 103 for eliminating moisture, etc. from untreated semiconductor wafer by heating the wafer with or without HMDS treatment, a cooling unit 104 for cooling the preheated wafer, and first and second heating units 105 and 106 for heating the wafer subsequent to, for example, being coated with the photo-resist solution to dry it. Each of the heating units 105 and 106 has upper heating plate and lower heating plate arranged in an overlapping fashion. On the other side of the passage 102, first and second applying units 107 and 108 are provided. The two applying unit 107, 108 is provided in order to coat, a photo-resist solution on the surface of the wafer which has been preheated and cooled, or in order to spray a developing solution to an exposed photo-resist film on the wafer. Though the preheating unit 103 and cooling unit 104 are shown provided in a plan array in FIG. 2 for convenience's sake, as a matter of fact, the preheating unit 103 is provided over the cooling unit 104.
A wafer conveying device 110 is mounted on the passage 102 to allow the wafer to be travelled in the Y direction by a drive mechanism, not shown, such as a ball screw. The wafer conveying device 110 includes a carriage 111 having two pairs of tweezers 112, 113 adapted to hold the wafer in place under a suction force. The two pairs of tweezers are arranged one at the upper side and one at the lower side in an overlapping fashion. The two pairs of tweezers 112, 113 can be moved independently to each other in the X direction (the width direction of the passage 102), simultaneously in the Y direction (longitudinal direction of the passage 102) and the Z direction (vertical direction), and further can be rotated independently or simultaneously in the θ direction as shown in FIG. 2. In order to allow the tweezers 112 and 113 to be moved as described above, a stepping motor and drive mechanism, not shown, such as a ball screw, are coupled to the carriage 111. The conveying device 110 is employed to convey the wafer W to a respective one of the aforementioned treatment units.
A wafer loading/unloading mechanism 120 is provided to the left side of body base 101 and houses a plurality of wafer cassettes 122, 123 with those untreated semiconductor wafers W B held in the respective wafer cassettes 122 and those treated wafers W F held in the respective wafer cassettes 123. A pair of tweezers 121 is provided in the wafer loading/unloading mechanism 120 to hold the wafer W under a suction force imposed to the lower surface of the wafer. Like the tweezers 112 and 113, tweezers 121 can be moved in the X and Y directions and can pick up the untreated wafer W B from the cassette 122 and store the treated wafer W F into the wafer cassette 123.
The pair of tweezers 121 of the wafer loading/ unloading mechanism 120 delivers the untreated wafer W B to those tweezers 112, 113 of the conveying device 110 and receives the treated wafer W F from those tweezers 112, 113 of the conveying device 110. That deliver/receive interface is provided at a boundary between the passage 102 and the wafer loading/unloading mechanism 120.
The delivering/receiving operation of the wafers is achieved relative to the respective treatment units by the tweezers 112 and 113 of the conveying device 110. The wafer W undergoes various treatments at the respective units 103 to 108 in accordance with a predetermined order. The operation of conveying wafers is all controlled by a control system, not shown. The various treatments at the treatment units 103 to 108 can freely be set by modifying the program of a control system. That is, the treatments can be effected at some treatment units alone in accordance with a modified treatment sequence.
FIGS. 3 and 4A to 4C show the aforementioned tweezers 112, 113 and 121 in more detail. In these Figures, a body 21 of the tweezers has three projecting support pins 22, 23 and 24 whereby the semiconductor wafer W is supported. The three-point-support is effective to prevent contamination of the wafer surface with dust. One of the three support pins have their open top end to allow the wafer to be vacuum-sucked there. An arcuate guide member 25 conforming to the peripheral edge of the wafer W is provided which, together with a stopper member 26, ensures the alignment of the wafer W. The wafer W is placed just on the tweezers in such a state as shown in FIG. 4A at which time it is neither aligned in a correct position nor vacuum-sucked. Then as shown in FIG. 4B, the pair of the tweezers is horizontally moved toward the stopper member 26 to allow the orientation flat Wa of the wafer to abut against the stopper member 26. The further horizontal movement allows the wafer W to slide over the support pins 22 to 24 into abutting engagement with the guide member 25 where it is stopped. Even if in the state shown in FIG. 4A the wafer W tends to be displaced away from a correct center of the tweezers, it is guided by the guide member 25 to align with a predetermined center position of the tweezers.
FIG. 5 shows an interface mechanism 30 which is provided at a boundary between the passage 102 and wafer loading/unloading mechanism 120. The interface mechanism has the function of allowing the wafer W to temporarily wait so that it is transferred between the tweezers 121 and the tweezers 112 and 113. In order to achieve this object, the interface mechanism comprises a holding member 31 for holding the wafer W with an assist of a vacuum suction mechanism and drive device 32, such as an air cylinder, for raising and lowering the holding member. When the wafer W is conveyed to the position shown in FIG. 5 by the tweezers 121 of the loading/unloading mechanism 120, the holding member 32 is raised to permit the semiconductor wafer W to be lifted for the wafer W to be held in place Then the wafer conveying device 110 on the side of the resist coating device 100 is moved to the position of the interface mechanism shown. The lowering of the holding member 31 allows the wafer which is held by the holding member 31 to be placed on the tweezers 112 or 113. The transfer of the wafer W from the tweezers 112, 113 to 121 is performed in the same fashion as set forth.
The step for forming a photo-resist film on the surface of a semiconductor wafer W by the device 100 will sequentially be explained below. The aforementioned step is performed based on a program which is initially stored i the aforementioned control system.
First a semiconductor wafer is picked up from the cassette 122 by the tweezers 121 in the loading/ unloading mechanism 120 and brought to the position of the interface mechanism. The wafer W being conveyed is delivered via the interface mechanism to one of pairs of tweezers, for example, tweezers 112, waiting at a location to the left end of the passage 102 and held there under a suction force. If the same types of semiconductor wafers are held in one cassette 122, an ID code can be attached to the cassette 122. It is thus possible to, upon the reading of the ID code from the cassette, select a corresponding manufacturing process program.
An explanation will be given below of the case where the wafer is treated in a sequence of the preheating unit 103, cooling unit 104, first coating unit 107 and first heating unit 105.
First the pair of tweezers 112, subsequent to picking up a first wafer W, is delivered to the preheating unit 103 where the wafer is set for preheating. The preheating unit 103 includes a heater plate on which the wafer is set. Preferably, the heater plate has three support pins by which the wafer is supported. When the wafer is supported by the three-point-support at a short distance from the heater plate surface by approximate 0.3 mm, wafer contamination with dust can be effectively prevented. During that period of time, the pair of tweezers 121 is moved toward the cassette 122 where it picks up a second wafer W and waits for the next operation at the interface mechanism. After the first wafer has been delivered to the preheating unit 103, the conveying device 110 receives the second wafer by tweezers 112 from the interface mechanism, and the wafer is held by the tweezers 112 under a suction force. The second wafer is held there until the first wafer has been treated at the preheating unit 103.
When the preheating of the first wafer W is completed, the conveying device 110 performs the next operation. That is, the pair of tweezers with no wafer placed thereon is moved so that the "preheated" first wafer is picked up from the preheating unit 103. When the preheating unit 103 is so vacated, the pair of tweezers 112 with the second wafer held thereon is moved to set the second wafer to the preheating unit 103. Then, tweezers 112, 113 is moved in the Y-direction, θ-direction and Z-direction, thereby locating at the cooling unit 104. Subsequently, the tweezers 113 with the pretreated first wafer placed thereon is moved in the X-direction so as to set the first wafer to the cooling unit 104. From the above description, it will be seen that there is an advantage of so providing two tweezers 112 and 113. That is, if, on the other hand, use is made of one pair of tweezers, the conveying device 110 has to be of such type that it first picks up a first wafer from the preheating unit 103, sets it to the cooling unit 104, picks up a second wafer and set it to the preheating unit.
During the aforementioned operation, at the wafer loading/unloading mechanism 120, a third wafer to be next treated by the tweezers 121 is placed at the interface mechanism in preparation for the next operation.
Next the wafer conveying device 110 picks up the third wafer by the tweezers 112 from the interface mechanism for holding it thereon and waits in that state until a treatment is completed at the cooling unit 104. When the cooling of the first wafer is completed, the wafer conveying device 110 picks up the wafer in the cooling unit 104 by empty tweezers 113 and sets it in the first coating unit 107 for a programmed photo-resist coating step to be carried out. When the treatment of the second wafer in the preheating unit 103 is completed during that coating period, then the conveying device 110 picks up that wafer by empty tweezers 113 from the preheating unit 103. A third wafer held by the tweezers 112 is sets in the preheating unit 103 and, at the same time, the second wafer held by the tweezers 113 is set in the cooling unit 104. The aforementioned operation is the same as already set out above.
If the preheating of the second wafer is completed prior to the completion of a cooling operation on the first wafer, a program may be run as will be set forth below. That is, a second wafer is picked up from the preheating unit 103 by the tweezers 113 with a nontreated third wafer held by the tweezers 112. The third wafer is set by the tweezers 112 in the heating unit 103 and a wait is made for the next operation to be made. Subsequent to cooling the first wafer in the unit 104, it is picked up by the tweezers 112 or 113 and set in the first applying unit 107. In the first applying unit, photo-resist solution is dropped and coated on the wafer surface by spinner coater.
When the first wafer is coated with a photo-resist in the first applying unit 107, the conveying device 110 picks up that wafer from the first applying unit 106 by the tweezers 113. The conveying device is moved to the right in the Y direction and the picked-up first wafer is set in the first heating unit 105 for heat treatment. After the cooling of the second wafer in the cooling unit 104 during the time period in which the first wafer is heated as set out above, the conveying device 110 picks up the second wafer and sets it in the first applying unit 107 where it is coated with a photo-resist.
After the first wafer has been heat-treated in the first heating unit 105 and coated with a desired photo-resist film, the conveying device 110 picks up the first wafer by tweezers 113 and is moved to the left in the Y direction and delivers the wafer which is held by tweezers 113 to the interface mechanism. In the interface mechanism, the wafer is preferably supported on the holding member at a short distance from the surface of the holding member in order to prevent contamination with dust. It is more preferable that waiting mechanism comprises a carrier cassette. The loading/unloading mechanism 120 picks up the treated wafer W F at the interface mechanism by means of tweezers 121 and located into the cassette 123 for storage. The aforementioned operation is performed in a sequential fashion until untreated wafers W B in the cassette 122 are all treated.
Although, in the aforementioned explanation, use has been made of the first applying unit 107 and first heating unit 105, the second applying unit 108 and second heating unit 106 may be used instead. If the photo-resist coating step and/or heating step take more time than at the other step or steps, then it may be possible to simultaneously employ two applying units 107 and 108 for coating the photo-resist solution and/or two heating units 105 and 106.
It is common practice to tentatively treat a wafer, in the step of forming the aforementioned photo-resist film thereon, so as to see whether or not a programmed process is proper. In this case it is necessary to pick up the "tentatively treated" test wafer W T from the cassette for inspection. In order to gain easy access to the wafer for pick-up, it is preferable to provide at the base of a cassette 123 a receiver 40 which can be drawn relative to the cassette. A knob 41 is provided at one end of the receiver 40 in which a wafer rest 42 is placed. The "tentatively treated" test wafer W T is placed via an opening 43 on the wafer rest 42 by the tweezers 121. The test wafer W T can be picked up readily by drawing the receiver 40 as shown in FIG. 6.
As already set forth above, although the first coating unit 107 and first heating unit 105 are employed in performing the aforementioned operation, it may be possible to use the second coating unit 108 and second heating unit 106 instead. If the photoresist coating step and/or heating step take more time than the other step or steps, it may be possible to simultaneously employ the two coating units 107, 108 and/or two heating units 105, 106.
As will be appreciated from the above, according to the present invention, a plurality of steps necessary to form a photo-resist film on the surface of the semiconductor wafer can be employed in a proper combination with other steps. That is, a heat treatment program can be selected in accordance with the kinds of wafers to obtain the best throughput from the most efficient combination.
The tweezers 112, 113 on the conveying device 110 can perform their own individual operation with high latitude. For example, if a preceding wafer is being treated at one unit, it cannot be replaced by a "current" wafer due to the presence of the preceding wafer. Even under the situation, it is possible, according to the present invention, to avoid such an inconvenience. Three or more pairs of tweezers can be employed in a proper fashion instead of two.
The various treatment units are provided along the passage 102 with a proper number placed on each side of the passage and hence an operation program of the conveying device 110 ca freely and readily be modified with greater latitude. Furthermore, since the preheating unit 103 and cooling unit 104 are provided one above the other, a floor space for installation can be saved a great deal.
The aforementioned apparatus of the present invention can also be employed for developing a photo-resist film which has been exposed with a predetermined pattern. In this case, the applying units 107 and 108 are employed for developing the wafer with a developing solution and for forming a resist pattern. For attaining this object, the developing apparatus is also provided in the units 107, 108. Employed is such a developing apparatus which develops an exposed photoresist film by spraying jet-stream of a developing solution onto the wafer being rotated with variable speed.
Furthermore, the two applying units 107 and 108 are employed such that one is used for coating a photoresist and the other for applying a developing solution on the wafer. As a result, the resultant apparatus can be used for performing both the functions. In this case, another interface mechanism can be provided on the right-hand end of the passage 102 as shown in FIG. 5 and if the delivery of the wafer to the exposure device is ensured, then it is possible to perform a complete series of operation from the coating of the resist to the developing of the resist.
It should be also noted that plurality of the treating sections 100 can be combined in series. In this case, the two or more sections 100 is arranged so as to an elongated passage 102 is formed. It is preferable to provide a waiting mechanism, for example, a carrier unit between the each unit 100. An example of the embodiment is shown in FIG. 7. In the drawing, 201 is a HMDS treating unit, 202 is a first preheating unit, 203 is a first cooling unit, 204 is a first applying unit, 205 is a second applying unit, 206 is a second preheating unit, 207 is a second cooling unit, 208 is an applying unit for surface coating.
In addition, the apparatus of the invention can be used for washing or cleaning surfaces of a wafer. | 4y
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to an airfoil apparatus for gas turbine engines and a method for fabricating such an apparatus.
[0002] Gas turbine engines typically include a number of airfoil structures that interact with fluids that pass through the engine. Some of those airfoil structures comprise portions of non-rotating stator (or vane) structures. Stator structures are often made from forged components that are installed between a pair of shroud (or casing) rings through brazed connections. Brazing is a convenient and effective technique for joining airfoils to shroud rings to fabricate the stator structure. However, brazing can form a relatively low-strength joint that may not withstand relatively high stresses at or near the braze location. In essence, brazing can produce joints that are not as strong as the forged material of the stator structure. In order to compensate for the lower mechanical properties of brazed connections, stablugs have been added to stator structures. Stablugs are thickened portions of the stator structure that help keep braze materials away from the airfoil, which is thin and typically experiences relatively high stresses during engine operation. Stablugs can take a variety of cross-sectional shapes, including “racetrack” shapes (i.e., having linear side portions and rounded end portions that generally do not match the of the stator structure) as well as “airfoil” shapes that generally correspond to the aerodynamic contour of the airfoil. Regardless of the cross-sectional shape, the stablug must extend into the main gas flowpath of the engine adjacent to the airfoil. For example, the stablug may radially extend 0.127 cm (0.050 inch) proud into the gas flowpath for any given stator, which for low aspect ratio airfoils used in new engine designs can be over 9% of the span of the airfoil into the gas flowpath.
[0003] The relatively thick stablugs that extend into the gas flowpath of the engine have an undesirable impact on engine performance and efficiency (e.g., measured in terms of pressure loss), especially with stators for which it is desired to have a relatively small span. The stablugs create flow blockage at the endwalls of the stator structure in the gas flowpath. Moreover, the presence of a stablug precludes the inclusion of any stator features at that location, which is at the outer diameter or inner diameter of the airfoil where the stator is attached to the shroud rings. However, other known possibilities present cost, reliability and assembly problems. For instance, simply omitting the stablug can cause the braze joint to incur higher stresses during engine operation. Some stablugs can be partially recessed (though not entirely recessed), but recessing the stablug cannot be accomplished with high solidity stator assemblies (i.e., those with low aspect ratios and high vane counts) and does not completely eliminate the inefficiencies associated with stablug use.
BRIEF SUMMARY OF THE INVENTION
[0004] A method of assembling a stator apparatus includes providing a first vane having an airfoil section located between a first platform section and a second platform section, positioning a first shroud ring adjacent to the first vane, welding the first platform section of the first vane to the first shroud ring relative to a first edge of the of the first platform section of the first vane, and welding the first platform section of the first vane to the first shroud ring relative to a second edge of the of the first platform section. The second edge is located opposite the first edge.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a flow chart of a stator apparatus assembly method according to the present invention.
[0006] FIG. 2 is an exploded cross-sectional view of a stator apparatus according to the present invention prior to assembly.
[0007] FIGS. 3 and 4 are cross sectional views of the stator apparatus at different points during assembly.
[0008] FIG. 5 is a cross-sectional view of the stator apparatus when fully assembled.
[0009] FIG. 6 is a front view of a portion of the stator apparatus when fully assembled.
DETAILED DESCRIPTION
[0010] FIG. 1 is a flow chart of a stator apparatus assembly method, which is suitable for fabricating a high pressure compressor (HPC) stator nozzle or other similar flowpath structures for a gas turbine engine. The steps illustrated in FIG. 1 are described with reference to physical structures shown in FIGS. 2-6 . However, it should be recognized that the methods of the present invention are applicable to structures that are different from the embodiments illustrated in FIGS. 2-6 .
[0011] As shown in FIG. 1 , an initial step of the assembly method involves forming subcomponents of the apparatus (step 20 ). The subcomponents can be formed using milling, precision forging, turning and/or other known processes as desired for particular applications. The step of forming the subcomponents (step 20 ) can provide at least some desired final material properties.
[0012] FIG. 2 is an exploded cross-sectional view of a stator apparatus prior to assembly, showing an outer shroud (or casing) ring 22 , a vane structure 24 , and an inner shroud (or casing) ring 26 . The vane structure 24 and the two shroud rings 22 and 26 are shown in FIG. 2 in their preliminary configurations after forming (step 20 ), although final shapes of those subcomponents can differ from the preliminary configurations. For example, possible final shapes of the subcomponents are indicated in phantom in FIG. 2 for reference.
[0013] As shown in FIG. 2 , the outer shroud ring 22 includes a radially inner surface 28 (or inner diameter surface) that defines a forward edge 30 and an aft edge 32 . A forward groove 34 and an aft groove 36 are formed along the radially inner surface 28 in a generally circumferential orientation. A forward weld backstrike surface 38 and an aft weld backstrike surface 40 are formed along the forward and aft grooves 34 and 36 , respectively, and each weld backstrike surface 38 and 40 extends radially inward from adjacent portions of the inner surface 28 . A raised portion 41 extends between the weld backstrike surfaces 38 and 40 along the inner surface 28 . The functions of the weld backstrike surfaces 38 and 40 and the grooves 34 and 36 are explained in greater detail below.
[0014] The vane structure 24 includes an airfoil 42 , an outer platform 44 and an inner platform 46 . The outer and inner platforms 44 and 46 are generally annular structures that define portions of a gas flowpath for an engine. The airfoil 42 extends between the outer and inner platforms 44 and 46 . The outer platform 44 defines an outer surface 48 and the inner platform 46 defines a preliminary inner surface 50 . A circumferential groove 52 is formed in the outer surface 48 of the outer platform 44 . In a preferred embodiment, the vane structure 24 is formed unitarily, although it is possible in alternative embodiments for portions of the vane structure 24 to be non-unitary and attached by suitable means.
[0015] The inner shroud ring 26 defines a preliminary radially outer surface 54 (or outer diameter surface) and an inward facing region 56 .
[0016] Turning again to the flow chart of FIG. 1 , the next step is to fixture all vanes 24 to the outer shroud ring 22 (step 58 ). Typically a plurality of circumferentially adjacent vane structures 24 are used to form an annular stator assembly for a gas turbine engine. At step 58 , all of the vane structures 24 are positioned adjacent to each other within the outer shroud ring 22 and secured in place using appropriate fixtures.
[0017] FIG. 3 is a cross sectional view of the vane structure 24 fixtured to the outer shroud ring 22 by an exemplary fixture 60 . Once fixtured, the vane structure 24 and the outer shroud ring 22 are welded together. Welding can be performed using conventional electron beam (EB) welding techniques. A first weld is formed at the aft edge 32 of the outer shroud ring 22 (step 64 ), and then a second weld is formed at the forward edge 30 of the outer shroud ring 22 (step 66 ) after the components are repositioned on the fixture 60 . The first weld extends along the interface between the inner surface 28 of the outer shroud ring 22 and the outer surface 48 of the outer platform 44 of the vane structure 24 , and extends from the aft edge 32 to the groove 36 . Likewise, the second weld extends along the interface between the inner surface 28 of the outer shroud ring 22 and the outer surface 48 of the outer platform 44 of the vane structure 24 , and extends from the forward edge 30 to the groove 34 .
[0018] The EB weld beam penetrates the areas of the first and second welds to the cavity formed by the grooves 34 , 36 and 52 , which are configured such that first and second welds do not bridge the grooves 34 and 36 . The weld backstrike surfaces 38 and 40 and the raised portion 41 of the outer shroud ring 22 are configured to help separate the first and second welds, and to limit deeper progress of the EB weld beam. This arrangement helps prevent the EB weld beam from stopping within the joint regions where the first and second welds are formed, which would be undesirable for weld integrity. The first and second welds can be formed by fixing the EB weld beam and rotating the components being welded such that welding is performed in a circumferential manner relative to substantially the entire inner diameter of the outer shroud ring 22 .
[0019] Next, wax is applied to the flowpath, that is, wax is applied between the airfoils 42 of adjacent vane structures 24 welded to the outer shroud ring 22 (step 68 ). Tape can be applied at flowpath joints between adjacent vane structures 24 prior to applying the wax, in order to help contain the wax. The wax gives the airfoils 42 additional rigidity during subsequent assembly processes.
[0020] Once wax has been applied at step 68 , the inner platform 46 of the vane structure 24 is machined to a final dimension (step 70 ).
[0021] Material is removed at the preliminary inner surface 50 of the inner platform 46 to form a finished inner surface 50 ′. Then the finished inner surface 50 ′ of the inner platform 46 is nickel flashed (i.e., nickel plated) to prepare it for brazing (step 72 ).
[0022] At this point, a honeycomb seal 74 can optionally be attached to the inward facing region 56 of the inner shroud ring 26 (step 76 ) (e.g., using a nickel braze). Next, the inner shroud ring 26 is machined to remove material from the preliminary outer surface 54 and define a finished outer surface 54 ′ (step 78 ). Then the finished outer surface 54 ′ of the inner shroud ring 26 is nickel flashed (i.e., nickel plated) to prepare it for brazing (step 80 ). Following nickel plating (step 80 ), the wax (and any tape) is removed from the flowpath (step 82 ), which can be accomplished by heating the wax to melt it away. The optional honeycomb seal 74 can be masked while performing nickel plating and/or brazing processes.
[0023] Next, the inner shroud ring 26 is slid into position inside the vane structures (step 84 ). Step 84 may require heating radially outer components (e.g., the vane structures) and/or cooling radially inner components (e.g., the inner shroud ring) in order to slide the inner shroud ring 26 into position while providing a close fit and easing assembly. Gaps between the inner shroud ring 26 and the vane structures 24 can be verified prior to brazing to assure proper fit. In order to facilitate later assembly steps, a braze foil can be tack welded to the finished outer surface 54 ′ of the inner shroud ring 26 when the ring 26 is slid into position inside the vane structures 24 .
[0024] FIG. 4 is a cross sectional view of the stator apparatus fixtured to the fixture 60 following assembly step 84 . The next assembly step is to braze (e.g., using a gold-nickel braze material) the inner shroud ring 26 to the vane structure 24 in order to secure those components to each other (step 86 ). The brazing process can be conducted in a conventional manner along substantially the entire interface between the finished outer surface 54 ′ of the inner shroud ring 26 and the finished inner surface 50 ′ of the inner platform 46 of the vane structure 24 . Brazing is performed circumferentially to secure all of the vane structures 24 to the inner shroud ring 26 . Brazing can be performed with the forward edge 30 facing downward in the fixture 60 .
[0025] After the inner shroud ring 26 has been secured to the vane structure 24 (step 86 ), sealant is applied to any circumferential gaps between adjacent vane structures 24 (step 87 ). The sealant helps to reduce undesired leakage and flow recirculation, and generally forms a non-structural bond between the adjacent vane structures 24 The sealant can be a ceramic cement, a metallic braze, a high-temperature epoxy sealant, or other suitable material.
[0026] Next, the outer and inner shroud rings 22 and 26 are machined to desired finished dimensions (step 88 ). At this step, the optional honeycomb seal 74 can also be ground to finished dimensions. Any further finishing steps can also be performed at this step, as desired for particular applications. For example, a timing notch can be formed in the inner shroud ring 26 through milling or electric discharge machining (EDM). Moreover, the shroud rings 22 and 26 can be optimally segmented as desired.
[0027] FIGS. 5 and 6 illustrate a fully assembled stator apparatus 90 .
[0028] FIG. 5 is a cross-sectional view and FIG. 6 is a front view of a portion of the stator apparatus 90 . As shown in FIG. 6 , a plurality of vane structures 24 (e.g., 100 or more vane structures) are arranged adjacent to each other in an annular configuration relative to an engine centerline CL between the outer shroud ring 22 and the inner shroud ring 26 . A sealant 92 is illustrated between adjacent vane structures 24 at both outer and inner platform 44 and 46 locations.
[0029] It should be recognized that the apparatus and method of the present invention provide a number of advantages. For example, a stator apparatus according to the present invention avoid the need for a stablug. Stablugs have been determined to cause a 1% loss in pressure over a non-stablug design according to the present invention for some applications, although total pressure loss will vary with the span of the airfoils of the stator apparatus and will generally be greater with relatively small span dimensions. Furthermore, the present invention provides a relatively easy and reliable assembly method that does not degrade forged material properties in the airfoils during welding or brazing processes. Subcomponents can be forged, and the assembly method can preserve forged properties.
[0030] Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. The particular shape and configuration of the stator assembly can vary as desired for particular applications, for instance, the present invention applies to cantilevered stators secured only at either an outer or inner shroud ring. Moreover, the particular assembly steps involved and the order in which those steps are performed can also vary as desired for particular applications. For instance, welding can be used at the outer shroud ring and brazing at the inner shroud ring or vice-versa. | 4y
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International Application No. PCT/EP2008/050556, filed Feb. 4, 2010 and claims the benefit thereof. The International Application claims the benefits of European. Patent Office application No. 09001524.9 EP filed Feb. 4, 2009. All of the applications are incorporated by reference herein in their entirety.
FIELD OF INVENTION
[0002] The invention relates to a turbine component with an easily removable protective coating, a set of turbine components, a turbine and a method for protecting a component.
BACKGROUND OF INVENTION
[0003] Turbine blades are often provided with metallic or ceramic protective layers for protection from oxidation or corrosion and from excessive introduction of heat, and are either shipped while fitted in a turbine or, in case of doubt, are shipped individually or multiply to allow them to be newly fitted again in situ in a plant.
[0004] Similarly, turbine blades have film cooling holes, which are necessary since the cooling makes a higher operating temperature of the turbine blade possible.
[0005] During transit, it may happen that the ceramic layer becomes scratched, and this may cause a crack if there is thermal stress. Similarly, the film cooling holes may be clogged by dirt and prevent the emergence of cooling air during operation.
SUMMARY OF INVENTION
[0006] It is therefore the object of the invention to solve the aforementioned problems.
[0007] The invention is achieved by a turbine component with an easily removable layer as claimed in the claims, turbine components as claimed in the claims, a set of turbine components as claimed in the claims, a turbine as claimed in the claims and a method as claimed in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Further advantageous measures that can be combined with one another as desired in order to achieve further advantages are listed in the subclaims.
[0009] FIGS. 1 , 2 , 3 and 4 show exemplary embodiments of a turbine blade,
[0010] FIG. 5 shows a gas turbine,
[0011] FIG. 6 shows a turbine blade and
[0012] FIG. 7 shows a combustion chamber,
[0013] FIG. 8 shows a list of superalloys.
[0014] The examples listed in the figures and in the description only represent exemplary embodiments of the invention.
DETAILED DESCRIPTION OF INVENTION
[0015] FIG. 1 shows a turbine component 1 , 120 , 130 , 155 with an outer hole 7 , which is adjacent an outer surface 13 of a substrate 4 . The invention is not restricted to turbine components.
[0016] An outer hole 7 means a hole in an outer wall of a hollow turbine component 1 , 120 , 130 , 155 .
[0017] The hole 7 is preferably a through-hole 7 , that is to say a film cooling hole in the case of a turbine blade 120 , 130 ( FIG. 6 ) or a combustion chamber element 155 ( FIG. 7 ).
[0018] The part that is identified by the reference numeral 4 is the substrate 4 of a superalloy ( FIG. 8 ) and preferably also has metallic and/or ceramic protective coatings 16 ( FIGS. 3 and 4 ), which are not represented in any more specific detail in FIGS. 1 and 2 .
[0019] The turbine component 1 , 120 , 130 , 155 is used at high operating temperatures, at least 700° C., in particular at least 850° C.
[0020] A final, further, outermost layer 10 is applied on the surface 13 of the substrate 4 or the metallic coating 16 (MCrAlY coating) or the ceramic coating 16 .
[0021] The outermost coating 10 can be easily removed at removal temperatures well below the operating temperature of the component 1 , 120 , 130 , 135 and preferably consists of an organic material, in particular of a polymer.
[0022] The high-temperature-resistant polymers are known from the prior art, and so too is the coating of the component 1 , 120 , 130 , 155 with the polymer. Coming into consideration as polymers are polyamides (Aurum), PEEK or PEK (polyether ketones).
[0023] The protective coating 10 may preferably contain at least one, particularly only one, dye (preferably inorganic material).
[0024] The coating 10 may preferably leave the film cooling hole 7 open ( FIGS. 1 and 3 ) or preferably also cover the opening partially, largely or entirely, as represented in FIGS. 2 and 4 .
[0025] If the hole 7 is narrowed, is also possible to prevent coarse dust particles from penetrating further into the hole 7 .
[0026] The component 1 , 120 , 130 , 155 is fitted in a device, preferably a gas turbine 100 , while the coating 10 is still present on the component 120 , 130 , 155 as shown in FIGS. 1 , 2 and 3 or FIG. 4 .
[0027] As a result of the lower removal temperature during commissioning (preferably start-up, test operation, . . . ) in comparison with the maximum operating temperatures of the gas turbine 100 , at the lower removal temperatures the protective coating 10 is thermally removed or vaporized by evaporation and burning or a similar chemical process and then exposes the film cooling hole 7 or removes itself from the surface of the component 1 , 120 , 130 , 155 . When the newly fitted component 1 , 120 , 130 is used for the first time, cooling is initially not yet necessary, so that it is quite acceptable for the cooling hole 7 still to be covered by the protective coating 10 .
[0028] The operating temperature for a gas turbine 100 is ≧800° C., in particular ≧1000° C. The protective layer 10 evaporates, burns or sublimates within the turbine 100 , preferably at least at 100° C., in particular ≧200° C., in particular at at least 300° C.
[0029] The difference between these two temperatures (operating temperature and removal temperature of the layer 10 ) is preferably at least 500° C.
[0030] If the hole 7 is covered by the layer 10 ( FIGS. 2 and 4 ) or narrowed ( FIG. 1 ), no dirt can penetrate into the hole 7 and temporarily or permanently clog it or constrict it (protection while in transit).
[0031] If the color of the layer 10 is different at one point, this is an indication of possible damage, and the component 120 , 130 , 150 can be examined at this point.
[0032] The turbine blades 120 , 130 of the first stage of the turbine 100 may preferably be of a different color than the turbine blades 120 , 130 of the second stage of the turbine 100 for better differentiation.
[0033] Similarly, refurbished and new turbine blades 120 , 130 , preferably of the same turbine stage, may be of different colors.
[0034] Similarly, moving and stationary blades 120 , 130 of one turbine stage of a turbine 100 may be of different colors.
[0035] Similarly, moving and stationary blades of one turbine stage but of different turbines 100 or types of turbine may be of different colors.
[0036] The color does not have to be monochrome.
[0037] Protective coatings 10 may also be applied in the case of steam turbines.
[0038] FIG. 5 shows a gas turbine 100 by way of example in a longitudinal partial section. The gas turbine 100 has in the interior a rotor 103 with a shaft 101 , which is rotatably mounted about an axis of rotation 102 and is also referred to as a turbine runner.
[0039] Following one another along the rotor 103 are an intake housing 104 , a compressor 105 , a combustion chamber 110 , for example toroidal, in particular an annular combustion chamber, with a number of coaxially arranged burners 107 , a turbine 108 and the exhaust housing 109 .
[0040] The annular combustion chamber 110 communicates with a hot gas duct 111 , for example of an annular form. There, the turbine 108 is formed by four successive turbine stages 112 , for example.
[0041] Each turbine stage 112 is formed, for example, by two blade rings. As seen in the direction of flow of a working medium 113 , a row of stationary blades 115 is followed in the hot gas duct 111 by a row 125 formed by moving blades 120 .
[0042] The stationary blades 130 are in this case fastened to an inner housing 138 of a stator 143 , whereas the moving blades 120 of a row 125 are attached to the rotor 103 , for example by means of a turbine disk 133 .
[0043] Coupled to the rotor 103 is a generator or a machine (not represented).
[0044] During the operation of the gas turbine 100 , air 135 is sucked in by the compressor 105 through the intake housing 104 and compressed. The compressed air provided at the end of the compressor 105 on the turbine side is passed to the burners 107 and mixed there with a fuel. The mixture is then burned in the combustion chamber 110 to form the working medium 113 . From there, the working medium 113 flows along the hot gas duct 111 past the stationary blades 130 and the moving blades 120 . At the moving blades 120 , the working medium 113 expands, transferring momentum, so that the moving blades 120 drive the rotor 103 and the latter drives the machine coupled to it.
[0045] The components that are exposed to the hot working medium 113 are subjected to thermal loads during the operation of the gas turbine 100 . The stationary blades 130 and moving blades 120 of the first turbine stage 112 , as seen in the direction of flow of the working medium 113 , are thermally loaded the most, along with the heat shielding elements lining the annular combustion chamber 110 .
[0046] In order to withstand the temperatures prevailing there, these may be cooled by means of a coolant.
[0047] Similarly, substrates of the components may have a directional structure, i.e. they are monocrystalline (SX structure) or only have longitudinally directed grains (DS structure).
[0048] Iron-, nickel- or cobalt-based superalloys are used for example as the material for the components, in particular for the turbine blade 120 , 130 and components of the combustion chamber 110 .
[0049] Such superalloys are known, for example, from EP 1 204 776 B1, EP 1 306 454, EP 1 319 729 A1, WO 99/67435 or WO 00/44949.
[0050] Similarly, the blades 120 , 130 may have coatings against corrosion (MCrAlX; M is at least one element of the group comprising iron (Fe), cobalt (Co) and nickel (Ni), X is an active element and represents yttrium (Y) and/or silicon, scandium (Sc) and/or at least one element of the rare earths, or hafnium). Such alloys are known from EP 0 486 489 B1, EP 0 786 017 B1, EP 0 412 397 B1 or EP 1 306 454 A1.
[0051] A thermal barrier coating, which consists for example of ZrO 2 , Y 2 O 3 —ZrO 2 , i.e. is unstabilized, partially stabilized or completely stabilized by yttrium oxide and/or calcium oxide and/or magnesium oxide, may also be present on the MCrAlX.
[0052] Columnar grains are produced in the thermal barrier coating by suitable coating methods, such as for example electron-beam physical vapor deposition (EB-PVD).
[0053] The stationary blade 130 has a stationary blade root (not represented here), facing the inner housing 138 of the turbine 108 , and a stationary blade head, at the opposite end from the stationary blade root. The stationary blade head faces the rotor 103 and is fixed to a fastening ring 140 of the stator 143 .
[0054] FIG. 6 shows in a perspective view a moving blade 120 or stationary blade 130 of a turbomachine, which extends along a longitudinal axis 121 .
[0055] The turbomachine may be a gas turbine of an aircraft or of a power plant for generating electricity, a steam turbine or a compressor.
[0056] The blade 120 , 130 has, following one after the other along the longitudinal axis 121 , a fastening region 400 , an adjoining blade platform 403 and also a blade airfoil 406 and a blade tip 415 .
[0057] As a stationary blade 130 , the blade 130 may have a further platform at its blade tip 415 (not represented).
[0058] In the fastening region 400 there is formed a blade root 183 , which serves for the fastening of the moving blades 120 , 130 to a shaft or a disk (not represented).
[0059] The blade root 183 is designed for example as a hammer head. Other designs as a firtree or dovetail root are possible.
[0060] The blade 120 , 130 has for a medium which flows past the blade airfoil 406 a leading edge 409 and a trailing edge 412 .
[0061] In the case of conventional blades 120 , 130 , solid metallic materials, in particular superalloys, are used for example in all the regions 400 , 403 , 406 of the blade 120 , 130 .
[0062] Such superalloys are known, for example, from EP 1 204 776 B1, EP 1 306 454, EP 1 319 729 A1, WO 99/67435 or WO 00/44949.
[0063] The blade 120 , 130 may in this case be produced by a casting method, also by means of directional solidification, by a forging method, by a milling method or combinations of these.
[0064] Workpieces with a monocrystalline structure or structures are used as components for machines which are exposed to high mechanical, thermal and/or chemical loads during operation.
[0065] The production of monocrystalline workpieces of this type takes place for example by directional solidification from the melt. This involves casting methods in which the liquid metallic alloy solidifies to form the monocrystalline structure, i.e. to form the monocrystalline workpiece, or in a directional manner.
[0066] Dendritic crystals are thereby oriented along the thermal flow and form either a columnar grain structure (i.e. grains which extend over the entire length of the workpiece and are commonly referred to here as directionally solidified) or a monocrystalline structure, i.e. the entire workpiece comprises a single crystal. In these methods, the transition to globulitic (polycrystalline) solidification must be avoided, since undirected growth necessarily causes the formation of transversal and longitudinal grain boundaries, which nullify the good properties of the directionally solidified or monocrystalline component.
[0067] While reference is being made generally to solidified structures, this is intended to mean both monocrystals, which have no grain boundaries or at most small-angle grain boundaries, and columnar crystal structures, which indeed have grain boundaries extending in the longitudinal direction but no transversal grain boundaries. These second-mentioned crystalline structures are also referred to as directionally solidified structures.
[0068] Such methods are known from U.S. Pat. No. 6,024,792 and EP 0 892 090 A1.
[0069] Similarly, the blades 120 , 130 may have coatings against corrosion or oxidation, for example (MCrAlX; M is at least one element of the group comprising iron (Fe), cobalt (Co) and nickel (Ni), X is an active element and represents yttrium (Y) and/or silicon and/or at least one element of the rare earths, or hafnium (HO). Such alloys are known from EP 0 486 489 B1, EP 0 786 017 B1, EP 0 412 397 B1 or EP 1 306 454 A1.
[0070] The density is preferably 95% of the theoretical density.
[0071] A protective aluminum oxide layer (TGO=thermal grown oxide layer) forms on the MCrAlX layer (as an intermediate layer or as the outermost layer).
[0072] The composition of the layer preferably comprises Co-30Ni-28Cr-8Al-0.6Y-0.7Si or Co-28Ni-24Cr-10Al-0.6Y. Apart from these cobalt-based protective coatings, nickel-based protective coatings are also preferably used, such as Ni-10Cr-12Al-0.6Y-3Re or Ni-12Co-21Cr-11Al-0.4Y-2Re or Ni-25Co-17Cr-10Al-0.4Y-1.5Re.
[0073] A thermal barrier coating which is preferably the outermost layer and consists for example of ZrO 2 , Y 2 O 3 —ZrO 2 , i.e. is unstabilized, partially stabilized or completely stabilized by yttrium oxide and/or calcium oxide and/or magnesium oxide, may also be present on the MCrAlX.
[0074] The thermal barrier coating covers the entire MCrAlX layer.
[0075] Columnar grains are produced in the thermal barrier coating by suitable coating methods, such as for example electron-beam physical vapor deposition (EB-PVD).
[0076] Other coating methods are conceivable, for example atmospheric plasma spraying (APS), LPPS, VPS or CVD. The thermal barrier coating may have grains which are porous, are provided with microcracks or are provided with macrocracks for better thermal shock resistance. The thermal barrier coating is therefore preferably more porous than the MCrAlX layer.
[0077] Refurbishment means that components 120 , 130 may have to be freed of protective layers after use (for example by sandblasting). This is followed by removal of the corrosion and/or oxidation layers or products. If need be, cracks in the component 120 , 130 are then also repaired. This is followed by recoating of the component 120 , 130 and renewed use of the component 120 , 130 .
[0078] The blade 120 , 130 may be hollow or be of a solid form. If the blade 120 , 130 is to be cooled, it is hollow and may also have film cooling holes 418 (indicated by dashed lines).
[0079] FIG. 7 shows a combustion chamber 110 of a gas turbine. The combustion chamber 110 is designed for example as what is known as an annular combustion chamber, in which a multiplicity of burners 107 , which produce flames 156 and are arranged in the circumferential direction around an axis of rotation 102 , open out into a common combustion chamber space 154 . For this purpose, the combustion chamber 110 is designed as a whole as an annular structure, which is positioned around the axis of rotation 102 .
[0080] To achieve a comparatively high efficiency, the combustion chamber 110 is designed for a comparatively high temperature of the working medium M of approximately 1000° C. to 1600° C. To permit a comparatively long operating time even with these operating parameters that are unfavorable for the materials, the combustion chamber wall 153 is provided on its side facing the working medium M with an inner lining formed by heat shielding elements 155 .
[0081] Each heat shielding element 155 of an alloy is provided on the working medium side with a particularly heat-resistant protective layer (MCrAlX layer and/or ceramic coating) or is produced from material that is resistant to high temperature (solid ceramic bricks).
[0082] These protective layers may be similar to the turbine blades, meaning for example MCrAlX: M is at least one element of the group comprising iron (Fe), cobalt (Co) and nickel (Ni), X is an active element and represents yttrium (Y) and/or silicon and/or at least one element of the rare earths, or hafnium (Hf). Such alloys are known from EP 0 486 489 B1, EP 0 786 017 B1, EP 0 412 397 B1 or EP 1 306 454 A1.
[0083] A thermal barrier coating which is for example a ceramic thermal barrier coating and consists for example of ZrO 2 , Y 2 O 3 —ZrO 2 , i.e. is unstabilized, partially stabilized or completely stabilized by yttrium oxide and/or calcium oxide and/or magnesium oxide, may also be present on the MCrAlX.
[0084] Columnar grains are produced in the thermal barrier coating by suitable coating methods, such as for example electron-beam physical vapor deposition (EB-PVD).
[0085] Other coating methods are conceivable, for example atmospheric plasma spraying (APS), LPPS, VPS or CVD. The thermal barrier coating may have grains which are porous, are provided with microcracks or are provided with macrocracks for better thermal shock resistance.
[0086] Refurbishment means that heat shielding elements 155 may have to be freed of protective layers after use (for example by sandblasting). This is followed by removal of the corrosion and/or oxidation layers or products. If need be, cracks in the heat shielding element 155 are then also repaired. This is followed by recoating of the heat shielding elements 155 and renewed use of the heat shielding elements 155 .
[0087] On account of the high temperatures in the interior of the combustion chamber 110 , a cooling system may also be provided for the heat shielding elements 155 or for their holding elements. The heat shielding elements 155 are for example hollow and, if need be, also have cooling holes (not represented) opening out into the combustion chamber space 154 . | 4y
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. patent application Ser. No. 11/191,624 filed on Jul. 28, 2005 which is a divisional application of U.S. patent application Ser. No. 10/441,843, filed on May 20, 2003 which claims the benefit of U.S. Provisional Application No. 60/458,865, filed on Mar. 28, 2003. U.S. patent application Ser. No. 10/441,843 is a continuation-in-part application of PCT International Application PCT/US02/34608 which was filed in the U.S. Receiving Office on Oct. 30, 2002. PCT International Application No. PCT/US02/34608 claims the benefit of U.S. Provisional Application No. 60/398,258, filed on Jul. 24, 2002, U.S. Provisional Application No. 60/391,809, filed on Jun. 25, 2002, and U.S. Provisional Application No. 60/340,905, filed on Oct. 30, 2001. The disclosures the above applications are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a coated fastener and particularly to a welded coated fastener having a coating that resists the adherence of an electrodeposited coating. The present invention further relates to vehicle assembly methods and other assembly methods in which fasteners are attached and coupled together.
BACKGROUND OF THE INVENTION
[0003] With ever increasing design demands, flexibility and adaptivity of unibody construction is increasingly required in order to provide vehicles that meet broader customer needs. Increases in the number of components and structures that are coupled to the unibody construction have led designers to consistently add threaded fasteners to the unibody frame. Variation in manufacturing tolerances require that the fastener couple to the unibody frame in a way that allows a degree of positional adjustment during final assembly. This positional adjustment is provided by using a female fastener that is an encaged fastener. Typically, this takes the form of a nut or fastener encaged in a structure that is attached to the inner body frame. The cage is configured to provide the nut with a range of movement so that when a component is coupled to the frame, the alignment of the component and frame can be adjusted until they meet manufacturing standards.
[0004] Prior to coupling of the components to the frame, however, the frames typically are painted or coated using electrocoat e-coat or electrodeposition coating processes. To date, the step of electrocoating the frame often results in the electrocoat paint adhering to the fastener or, with a caged fastener, causes the fastener to adhere to the cage. This prevents the fastener from being adjustable within the cage and, therefore, causes tolerance problems in the final assembly of the product. In the case of threaded fasteners, the application of the electrocoat paint to the fastener's threads increases problems in the coupling of a mating fastener. To prevent the tolerance problems, post-process inspection after painting is required to ensure that the fasteners are not adhered to the cage or fastener thread. Should post painting of the threads occur or the fastener become adhered to the cage by the electrocoat coating, post-process rework must be conducted to clean the fastener.
SUMMARY OF THE INVENTION
[0005] Accordingly, this invention provides a fastener system that is weldable to a substructure that overcomes the problems and disadvantages of the fasteners of the prior art. Generally, a weldable fastener is disclosed that has a coating applied to at least one surface of the fastener. In one embodiment, the invention includes a threaded fastener in a fastener cage capable of fastening the fastener to a substructure, the cage having a coating which inhibits additional coatings, particularly an electrodeposition coating, from sticking to the cage.
[0006] In accordance with the teachings of another embodiment of the present invention, there is provided a weld stud assembly for use with a drawn arc welding system that overcomes the deficiencies of the prior art. The weld stud assembly has a head having a weldment area defined on the weld stud head. A coating is provided to at least apportion of the threads of the weld stud assembly to inhibit the adhesion of paint to the threaded area.
[0007] In another aspect of the invention, a cage nut assembly has a body having a threaded bore, a cage enclosing at least a portion of the body and providing a limited range of movement to the body within the cage. The cage has a coating on a surface that is formulated to prevent the deposit of an electrodeposition coating during further processing involving the cage nut assembly.
[0008] In yet another aspect of the invention, a cage nut assembly has a body having a threaded bore, a cage enclosing at least a portion of the body and providing a limited range of movement to the body within the cage. The cage has a coating on a surface with the surface tension of the coating being greater than about 25 mNm −1 and less than about 36 mNm−1.
[0009] The invention further provides a weldable metallic fastener with a flange configured to be welded to a surface and a threaded portion at least partially coated with a coating. The coating is applied as an aqueous composition including a binder, micronized polytetrafluoroethylene, and micronized polyethylene. The binder includes phenoxy resin, epoxy resin, or both. In a further embodiment, a weldable threaded fastener configured to be welded to a surface has a coating on a portion of the fastener, the coating including an epoxy material and polyethylene wax.
[0010] In another embodiment, a weldable metallic fastener having a base configured to be welded to a surface is coated with a coating comprising a binder component, a polyethylene wax, and polytetrafluoroethylene. The binder component may include an epoxy resin, a phenoxy resin, an acrylonitrile-butadiene-styrene [ABS] copolymer, a different styrenic component, another thermoplastic material, or combinations of these.
[0011] In yet another embodiment, a metallic fastener is coated with a coating including polytetrafluoroethylene and a binder selected from phenoxy resin, epoxy resins, and combinations of these.
[0012] In a method of the invention, an electrodeposition coating is prevented from being applied to a portion of a fastener that is configured to be coupled to a surface by coating a portion of the fastener with an epoxy coating including polyethylene wax. The fastener is fastened to a body, and the body is electrodeposition coated. The epoxy coating on the portion of the fastener resists wetting of the electrodeposition coating, so that the electrodeposition coating does not adhere or can easily be removed from that portion.
[0013] In a further method, a portion of a fastener configured to be coupled to a body is coated with a first coating. The first coating adheres to the fastener and prevents adhesion of a second coating. The fastener is then coupled to a body and the second coating is applied to the body. The second coating does not adhere to the areas of the fastener with the first coating.
[0014] In another embodiment, two articles are connected with a threaded fastener. A portion of the threaded fastener is coated with a first coating comprising a wax, then the threaded fastener is attached to a first article. A second coating is applied to the first article and fastener, but the second coating does not coat the portion coated with the first coating. Finally, a second article is connected to the first article with the threaded fastener.
[0015] In yet a further method a vehicle, such as an automotive vehicle is assembled by coating at least a portion of a weldable fastener with a first coating composition. The coating composition includes a component that provides the coating with a surface tension of up to about 30 mNm −1 . The fastener is welded to a vehicle component that is then coated by electrodeposition coating, in which step the electrodeposition coating does not substantially adhere onto the portion of the fastener that was coated with the first coating. By this we mean that the either no electrodeposition coating covers the portion or that any minor amount that might impinge on the portion can be easily removed, e.g. by brushing or knocking it off.
[0016] In a still further method, torqueing of a second fastener onto a first fastener is improved, particularly variation in applied torque is reduced compared to when an uncoated fastener is used, by coating a portion of the first fastener that interfaces with the second fastener with an epoxy coating that includes a polyethylene wax. In the method, the first fastener is coated with the epoxy coating including the wax, the fastener is fastened to a body, the body is coated by electrodeposition (which does not coat the coated first fastener portion), and, finally, the second fastener is coupled onto the first fastener.
[0017] Finally, the invention provides a method for applying an electrodeposition paint to a metallic fastener that is configured for coupling to a surface. A coating composition comprising epoxy resin and one or both of micronized polyethylene wax and micronized polytetrafluoroethylene is applied to a portion of the fastener and formed into a solid coating layer before the electrodeposition paint is applied. The electrodeposition paint does not substantially adhere to the coating layer.
[0018] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
[0020] FIG. 1 is a perspective view of the cage nut fastener in its unassembled condition;
[0021] FIG. 2 is a perspective view of the cage nut of the present invention in its assembled configuration;
[0022] FIG. 3 is a cross-section of the cage nut in FIG. 2 showing the relationship of the coating with respect to the fastener and the cage;
[0023] FIG. 4 is a side view of the drawn arc weld stud according to the teachings of the present invention;
[0024] FIG. 5 is a bottom view of the drawn arc weld stud according to FIG. 4 ;
[0025] FIG. 6 is a side view of the drawn arc weld stud according to FIG. 4 being coupled to a laminate sheet; and
[0026] FIG. 7 represents a chart depicting the required torque to meet a predetermined torque load.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. While the application describes a weldable cage fastener and a weldable stud, the application is equally applicable to any weldable or other fastener having a surface which resists the adherence of paint, and particularly electrodeposited paints known as electrocoat [e-coat] or ELPO systems.
[0028] The weldable threaded fastener 8 is configured to be coupled to a surface and has a coating on a portion of the threaded fastener. The fastener is configured to be welded to the surface. Optionally, the fastener is a weldable cage and the coating is on the body of the fastener. Optionally, the coating is on the cage and the fastener has a weldable base. For example, the threaded fastener is a welded stud or a welded nut.
[0029] The coating has a surface tension low enough so that a selected second coating, preferably an electrodeposition coating, will substantially not adhere to it. In a preferred embodiment, the coating has a surface tension of greater than 25 and less than 36 mNm −1 , and preferably greater than 27 and less than 32 mNm −1 , and most preferably about 28 mNm −1 , as measured using a Rame-Hart contact angle goniometer when calculated using harmonic mean. In a preferred embodiment, the coating comprises a binder, which includes at least one, but may include a plurality of resin components, and a component that provides the desired low surface tension to the surface of the coating. In describing the invention, “resin” may also, where appropriate, include “polymer” as well as oligomers and certain monomeric materials (e.g., the diglycidyl ether of bisphenol A) that are suitable for use in a coating binder.
[0030] The coating is formulated to prevent the deposit of a selected second coating, e.g. an electrodeposition coating, upon further processing. Although the coating includes a low surface tension binder component, e.g. a siloxane polymer for that purpose, a convenient way to so formulate a coating is to include a low surface tension solid that will come to the surface as the coating layer is formed. Suitable examples of materials that can provide the desired low surface tension include, without limitation, polyalkylene waxes, particularly polyethylene waxes, and poly(ethylene-copropylene); fluorinated polyalkylenes such as polytetrafluoroethylene and polyhexaluoropropylene; natural waxes such as montan and carnauba waxes; certain vinyl polymers, such as poly(vinyl fluoride), poly(vinylidene fluoride), and polymers of longer chain vinyl esters, such as poly(vinyl butyrate) and poly(vinyl octanoate); non-functional poly(oxyalkylene) waxes such as poly(oxyalkylene)-dimethylethers like poly(oxyethylene)-dimethylether waxes, poly(oxyalkylene)-block-poly(oxydimethylsilylene)-block-poly(oxyalkylene) solid copolymers; and combinations of these.
[0031] In another preferred embodiment, the coating comprises a mixture of polyethylene and polytetrafluoroethylene. Based on the combined weights of polyethylene and polytetrafluoroethylene, the coating contains about 20 to about 80 weight percent polyethylene, preferably about 30 to about 70 weight polyethylene, more preferably about 40 to about 60 weight percent polyethylene, the remainder being polytetrafluoroethylene.
[0032] It is believed that it is particularly beneficial to include a wax as at least a part of the surface tension-reducing component. Waxes provide the desired surface tension reducing properly to the coating, in addition, are likely to form a wax-rich layer at the surface of the coating because a wax will substantially melt at a typical baking temperature for the coating. In contrast, certain surface tension-reducing materials, for example poly (tetrafluoroethylene), would generally not be expected to melt and coalesce at typical coating bake temperatures.
[0033] Fluoropolymers used as a surface modifying component of the coating compositions of the invention include generally homopolymers and copolymers wherein the monomer of the homopolymer or at least one of the monomers of the copolymer contains fluorine. In a preferred embodiment, the fluoropolymers of the invention are prepared from perfluorinated monomers.
[0034] A preferred class of fluoropolymers includes homopolymers and copolymers of tetrafluoroethylene (TFE). The homopolymer of tetrfluoroethylene is known as polytetrafluoroethylene, and is commonly available as a line of Teflon® polymers of Dupont. In another embodiment, the fluoropolymers of the invention include copolymers of TFE with hexafluoropropylene (HFP). In another embodiment, fluropolymers are prepared by the copolymerization of TFE and perfluoroalkylvinyl ethers such as perfluoropropylvinyl ether. Other fluoropolymers of the invention include ethylene/tetrafluoroethylene copolymers, and polyvinylidene fluoride.
[0035] Fluoropolymers used in the coating layer of the invention may be prepared by known methods of solution or emulsion polymerization. The fluoropolymers may be used as emulsions, solutions, or as solid particles. Aqueous polyethylene and/or polytetrafluoroethylene dispersions are commercially available. In one embodiment, both polyethylene and polytetrafluoroethylene are included in the coating. The polyethylene is preferably from about 20 to about 80 weight percent, more preferably from about 40 to about 60 weight percent, based on the combined total weights of the polyethylene and polytetrafluoroethylene.
[0036] With reference to FIGS. 1-6 , a weldable threaded fasteners 8 which are configured to be coupled to a surface are shown. The fastener has a coating layer 35 configured to resist the adhesion of electro-deposed paint. Generally, the coating 35 has a binder component and a surface tension reducing component that resists adhesion to the coated surface by a selected second coating, particularly by an electrodeposition coating.
[0037] With reference to FIGS. 1-3 , a cage nut fastener, shown generally at 8 , has a body 16 coupled to a planar base 12 . The body 16 and planar base 12 define a threaded through bore 14 . Planar base 12 has an upper base surface 18 and lower base surface 20 . The cage nut assembly 8 further has a cage 22 which is generally disposed about the planar base 12 . The cage 22 has a cage upper surface 34 and cage lower surface 32 . Additionally, the cage 22 defines two pair of flanges 28 . The flanges 28 define cutouts 26 which generally correspond to the shape of the body 16 .
[0038] As can be best seen in FIG. 2 , the flange elements 28 are folded to enclose the planar base 12 of the body 16 . The flanges 28 are positioned so as to restrict the movement away from the cage 22 of the body 16 . Additionally, the cutouts 26 are positioned so as to restrict the planar movement of the body 16 within the assembly.
[0039] The cage 22 is configured so the body 16 has a limited range of movement. As can be seen in FIGS. 2 and 3 , the cage allows slight movement away from the cage upper surface 34 as well as allowing planar movement generally parallel to the cage upper surface 34 . This planar movement is generally restricted and defined by the space between the cutouts and the body 16 .
[0040] As best seen in FIG. 3 , the cage 22 has a coating layer 35 (as described below) disposed on a surface which directly faces the hexagonal body 16 or planar base 12 . This coating provides a surface that has a low wetability, and preferably has a lower wetability than the body 16 . This significantly reduces the amount of wetting of any coatings subsequently sprayed onto the as coated cage 22 . The coating preferably has a surface tension greater than about 25 mNm −1 and less than about 36 mNm −1 . While the coating 35 is shown on the cage 22 , it is envisioned that the coating 35 can equally be applied to the body 16 and/or the planar base 12 . The coating layer 35 can cover the entire shank 112 or can cover a portion of the shank 112 . Further, the coating layer 35 can be placed within the threads 117 while leaving the tips of the threads 121 exposed (see FIG. 6 ).
[0041] FIG. 4 represents the drawn arc weld stud 110 according to the teachings of the present invention. The weld stud 110 is formed of three major components; a shank 112 , a head 114 , and an annular weldment area 116 . By way of non-limiting example, the shank 112 can be a M6 threaded fastener. Equally, the shank can take the form of pine-tree connector or other sized threaded fastener. The shank 112 defines a coating layer 35 (as described below) which resists to adherence of e-coat to the fastener.
[0042] The head 114 portion is formed using cold heading methodologies. The head 114 for a M6 fastener has an exterior diameter of about 13 mm and a thickness of about 2 mm. The head further has a flat lower surface 115 having a diameter of about 13 mm. The strength of the fastener is a function of the thickness of the head. As such, as the thickness of the head is increased, generally the strength of the fastener 110 is increased. Increasing the strength of the fastener often leads to an undesirable failure of the interface of the fastener and the laminate material. Such failures lead to the fastener being pulled out of the laminate material, leaving a hole in the thin sheet metal.
[0043] The annular weldment area 116 has an exterior radius 118 which equals the exterior radius of the lower surface 115 of the head 114 . While an annular weldment area 116 is shown, it should be understood that standard circular weldment areas, are also applicable. For a M6 stud shank, the exterior radius of the head 114 is about 13 mm. The interior radius of the weldment area 116 has a radius of about 11 mm. The resulting weldment area being about 150 mm 2 . Each head 114 has a thickness T. The thickness 119 of the weldment is approximately 20% to 35% of the value of T.
[0044] To exemplify the application of this invention, FIG. 6 shows a fusion connection between a stud 110 and a laminate structure 120 . The stud 110 corresponds in design to that of FIG. 4 before welding, and reference is made to the description of FIG. 6 to avoid repetition.
[0045] In use, the stud 110 of FIG. 6 is placed in contact with the laminate structure 120 with the flat edge 22 of the annular weldment area 116 touching the laminate structure 120 . A welding current is then applied. After application of the welding current, the stud 110 is withdrawn to form an arc. While the arc is burning, both the flat edge 122 of the stud 110 and parts of the structure 120 melt. After a prescribed time, the stud 110 is plunged into the molten metal. The welding current is switched off before or during plunging. Then, the weld cools down. As shown in FIG. 6 , part of the circumferential edge 122 has melted. Part of the molten metal has entered the cavity 124 defined by the annular weldment area. The weld is substantially annular. The stud 110 and the structure 120 have a common weld area 126 that has set. Of course, the other illustrated embodiments of this invention operate in similar fashion. After the welding of the stud to the structure, the coating layer 35 , which has been exposed to a significant amount of heat, retains it capacity to resist the adherence of paint, and particularly e-coat paints.
[0046] The coating 35 of the invention functions to prevent or inhibit the deposit of an electrodeposition coating upon further processing. Preferred coatings have a surface tension such that they are poorly wetted by an aqueous electrodeposition bath. In one aspect, it is believed that the lower surface energy of the preferred coatings of the invention act to prevent deposition at least in part by preventing the surface of the coated part from being wetted by the electrodeposition bath. The coating 35 may be used to prevent adhesion of other selected second coatings that are applied to uncoated areas of the fastener and/or the articles to which the fastener is attached.
[0047] In one embodiment, the binder component of the coating used to prevent adhesion of a further coating layer preferably comprises epoxy resin. The epoxy resin is selected to provide desirable coating properties, e.g. good adhesion and good abrasion resistance so that the coating remains intact during fabrication with the fastener. In theory, many kinds of epoxy binders are suitable and provide such desirable coating properties. The epoxy binder may be thermoset, i.e., crosslinked, or, if of a suitably high molecular weight, may be thermoplastic. Specific examples of suitable epoxy resins include, without limitation, bisphenol A-type epoxy resins prepared from the reaction of bisphenol A and the diglycidyl ether of bisphenol A, epoxy novolac resins, phenoxy resins, such resins modified to be water-dispersible (for example, by reaction of terminal epoxide group or of hydroxyl groups with a dicarboxylic acid or a cyclic acid anhydride), and combinations of these. When the coating composition is formulated to be thermosettable, a suitable curing agent or crosslinker is included in the binder. Typical crosslinkers for epoxy resins include, without limitation, dianhydrides, polyamines and amino resins such as amino formaldehyde resins, polyisocyanate crosslinkers, and polyepoxides (for carboxyl-functionalized resins). In the case of aqueous coating compositions, the crosslinking resin may be mixed with a water-dispersible epoxy resin before dispersion in the aqueous medium. In a preferred embodiment, the crosslinkers are non-yellowing. Non-yellowing coatings may be desirable in some cases where appearance is at a premium, or where it is desired to further pigment the coating to provide a desired surface appearance.
[0048] In a preferred embodiment, the coating of the invention includes, based on combined weights of solid binder and surface tension-reducing component, from about 1 to about 50% by weight of the surface tension-reducing component. In a preferred embodiment, the surface tension-reducing component is present in an amount of about 5% by weight or greater, preferably about 10% by weight or more, more preferably from about 35% by weight or more, again based on combined weights of solid binder and surface tension-reducing component. The surface tension reducing component may be from about 1 to about 70%, more preferably from about 35 to about 60 percent by weight of the combined weights of solid binder and surface tension-reducing component. Preferably, the surface tension-reducing component is present at about 70% by weight or less, and more preferably at about 60% by weight or less, and even more preferably at about 50% or less, again based on the combined weights of solid binder and surface tension reducing component.
[0049] The total solids by weight of the coating compositions of the invention is chosen so as to deliver an appropriate amount of coating to the surface, and to provide a coating composition with suitable viscosity. The solids content may depend upon whether the coating composition is aqueous or solvent borne, as it is generally desirable to minimize organic emissions. For example, preferred coatings 35 may be applied at a weight of about 2 to 9 g/sq. ft., preferably about 3 to 5 g/sq. ft. Generally the percent by weight of the solids in a preferred aqueous coating composition ranges from about 10% to about 65%. In another embodiment, referring still to aqueous compositions, the compositions have 20% or more by weight solids, preferably 30% or more and more preferably 35% or more by weight solids. Preferably, the maximum weight percent solids is 65%, more preferably 60%. In other preferred embodiments, the weight percent solids is 50% or less. In a preferred embodiment, the solids are 45% or less by weight percent. In addition to the solids, the coating compositions of the invention contain from 1 to 40% water, preferably from 5-30% water.
[0050] The aqueous coating compositions of the invention may also contain organic solvents to promote a stable dispersion of the binder. In a preferred embodiment, the compositions contain 30% or less organic solvents, preferably 25% or less. As a general rule, the compositions may contain a minimum of 1% organic solvents, preferably a minimum of 10% by weight organic solvent. Non-limiting examples of volatile organic cosolvents to be used in the coating compositions include propanol, butanol, ethylene and propylene glycol ethers and ether acetates and 1-(2-butoxyethoxy) ethanol.
[0051] In addition to the solvents, resin, and surface tension modifier, the compositions used to form the coating of the invention can contain further components such as pigments, rheology modifiers, and other conventional additives. For example, inorganic pigments such as titanium dioxide, iron oxides, and other oxide pigments or organic pigments may be added to the coating compositions to provide a desired level of pigmentation in the coatings.
[0052] In another embodiment, the coating compositions of the invention can contain, in addition to the epoxy resin, a second resin or resins that provide further advantages. In a preferred embodiment, the coating contains a thermoplastic polymer selected from the group consisting of thermoplastic elastomer polymers, a styrenic component such as styrenic copolymers, ABS and SAN, a vinyl polymer such as a polyvinyl ester or a poly(vinyl chloride), or other polymers.
[0053] Elastomeric polymers include generally polymers based on diene functional monomers such as, without limitation, butadiene and isoprene. Non-limiting examples of such polymers include acrylonitrile butadiene elastomer (NBR), butyl rubber (IRR), isobutylene-isoprene elastomer, ethylene-propylene-diene terpolymer (EPDM), ethylene/butane elastomer, ethylene/octane elastomer, isobutylene-paramethylstyrene elastomer (IMS), polybutadiene elastomer (BR), polyisobutylene, polyisoprene (IR), and styrene-butadiene rubber (SBR). Such elastomeric polymers may be provided as solutions, suspensions, or in a preferred embodiment as particles. The polymers may be prepared by known processes by copolymerizing neat monomers, or by carrying out the copolymerization by emulsion polymerization or in solution in organic solvents.
[0054] In another embodiment, toughened epoxy resins may be produced by the bulk polymerization of the epoxy in the presence of dissolved rubber or elastomeric polymers as described above. Alternatively, the compositions of the invention may be prepared by blending the epoxy resin and the rubber particles.
[0055] The coating compositions of the invention are generally heated or baked for a short period of time to dry, coalesce, and, if appropriate to effect cure or crosslinking, of the coating. In a non-limiting example, the coating may be baked to 375° F. peak metal temperature for 2-5 minutes. A typical bake cycle is 400-425° F. for 20-30 minutes. An appropriate bake cycle for a specific coating depends upon the binder component and may be determined by straight-forward testing.
[0056] In a preferred embodiment, the coating composition of the invention is prepared from EPC-1760 E-Coat Block product manufactured by Environmental Protective Coatings of Ostrander, Ohio. The E-Coat Block product typically contains less than 5% by weight dimethylethylanolamine and less than 12% by weight of volatile organic solvents such as n-butyl alcohol, butylcellosolve, and butylcarbatol. The compositions contain from about 38 to about 43% by weight solids and have a density of from about 8.8 to 9.2 pounds per gallon. As provided, the composition has a Zahn cup no. 2 viscosity of 35-45 seconds at 77° F.
[0057] In another embodiment of the invention, a metallic fastener 8 is disclosed having a protective surface coating. The coating 35 is formed from a coating containing as a binder epoxy resin, preferably comprising phenoxy resin, optionally combined with a second, thermoplastic polymer. The coating further contains micronized polyethylene wax, micronized polytetrafluoroethylene, and pigment material. The second thermoplastic polymer preferably includes acrylonitrile-butadiene-styrene copolymer, polyvinyl chloride polymer, or both. The micronized polyethylene wax and the micronized polytetrafluoroethylene in the coating have a weight ratio to each other of about 60 to about 40 weight percent micronized polyethylene to about 40 to about 60 weight percent micronized polytetrafluoroethylene. Preferably, the solid binder and the polyethylene and polytetrafluoroethylene coating have a weight ratio to each other of about 40 to about 60 weight percent binder to about 60 to about 40 weight percent of the polyethylene and polytetrafluoroethylene.
[0058] In another embodiment of the present invention, a fastener is coated with an aqueous coating composition. The aqueous coating comprises, as binder, dispersed epoxy resin, preferable comprising phenoxy resin, and optionally comprising a second thermoplastic resin. The binder may also include a bisphenol A-type epoxy resin. The aqueous coating composition further comprises micronized polyethylene wax, micronized polytetrafluoroethane, and a pigment material.
[0059] In another embodiment of the present invention, a method for applying electro-deposition paint to a metallic fastener 8 is disclosed. The fastener 8 is configured for coupling to a surface and has a coating 35 on a portion of the fastener with a protective coating composition as described above.
[0060] After applying the electro-deposition paint to a metallic fastener 8 , the fastener and the protective coating precursor suspension are cured at about 400 degrees F. for about 30 minutes. After the fastener 8 is coupled to the structure, an electro-deposition paint is applied to the fastener. The portion of the fastener 8 coated with cured protective coating precursor defines a surface portion of the fastener where the electro-deposition paint will not contact metal of the fastener when the electro-deposition paint is applied.
[0061] In a particularly preferred embodiment, the fastener is coated with a composition including about 12 to about 20 weight percent binder particles comprising epoxy resin and thermoplastic resin, the epoxy resin phase derived from bisphenol A and epichlorohydrin, the thermoplastic resin phase derived from blended acrylonitrile-butadiene-styrene copolymer and polyvinyl chloride polymer; about 5 to 12 weight percent micronized polyethylene wax; about 2 to about 8 weight percent micronized polytetrafluoroethane; about 2 to about 20 weight percent pigment; about 25 to about 65 weight percent water; about 50 to about 20 weight percent organic cosolvent; and about 0.5 to about 2 weight percent of a neutralizing amine. The coating coats a threaded region of the fastener. The fastener may be fastened, e.g. by welding, to a body prior to applying the coating composition.
[0062] The threaded second fastener attachment portion of the first fastener coated with the protective coating defines a surface portion of the first fastener where the electro-deposition paint is repelled when the electro-deposition paint is applied.
[0063] Referring to FIGS. 1-3 , the cage nut has a body defining a threaded bore therethrough. A cage is disposed about at least a portion of the body. The cage provides a limited range of movement of the body within the cage. Further, the cage has a coating on at least one surface which has a surface tension of greater than 25 and less than 36 mNm −1 and preferably greater than 27 and less than 32 mNm −1 and most preferably about 28-29 mNm −1 , as measured using a Rame-Hart contact angle goniometer when calculated using harmonic mean. The body has a planar base while the cage defines a pair of flanges which cover at least a portion of the base. The coating is disposed between the flanges and the base.
[0064] The cage has flange members disposed about a least a portion of the body and is configured to limit the range of motion of the body. The body is disposed on the cage upper surface. The cage has at least one surface coated with a layer which is configured to function to prevent the deposit of an electrodeposition coating upon further processing and has a lower surface and the coating is further disposed on the lower surface.
[0065] In one embodiment, a weldable threaded fastener configured to be welded to a surface has a coating on a portion in which coating includes at least an epoxy material and a wax, preferably a polyethylene wax. The coating preferably further includes polytetrafluoroethylene at its surface. The coating may be thermoplastic or cured. The coating preferably has a surface tension of from about 27 mNm −1 to about 32 mNm −1 . The coating may be on a body portion of the fastener. When the fastener has a weldable cage, such as described with reference to the figures, the coating may be on the cage.
[0066] In another embodiment, the present invention provides a method of preventing e-coat from being applied to a fastener, a fastener being configured to be coupled to a surface. The method contains the steps of: a) coating a portion of the fastener with an epoxy coating including a wax, particularly a polyethylene wax; b) fastening the fastener to a body; and c) e-coating the body, wherein the coating functions to resist wetting of the e-coat. Optionally, fastening the fastener body is welding the fastener to a body such as welding a cage of a cage nut to the body.
[0067] The wax may include a polyfluoroethylene component. For example, a mixture of polyethylene wax and polytetrafluoroethylene may be in the applied coating composition. The coating formed therefrom will have both polyethylene and polytetrafluoroethylene at its surface. If the applied coating is baked, the polyethylene may melt and coalesce, and the coalesced polyethylene may include particulate polyethylene or (if the bake temperature is high enough) may be a mixture of polyethylene and polytetrafluoroethylene. Preferably, a sufficient amount of polyethylene and, optionally, polytetrafluoroethylene is included in the coating to provide a surface tension of less than 36 mNm −1 .
[0068] The portion of the fastener coated is preferably a threaded portion or a bearing region. The coating may contain a pigment as desired, for example to provide a desired color or gloss.
[0069] In a variation of the invention, a portion of a fastener configured to be coupled to a body is coated with a first coating. The first coating adheres to the fastener and prevents adhesion of a second coating. The fastener is then coupled to a body and the second coating, which, for example and without limitation, may be an electrodeposition coating or other aqueous coating, is applied to the body. The second coating does not adhere to the areas of the fastener with the first coating. The fastener may be coupled with the body in any conventional way, including welding, gluing, screwing, riveting, by sliding into a slot, as part of a threaded nut and bolt or screw combination, and so on. The fastener may be coupled to the surface of the body in some coupling methods or may extend through the surface in other methods.
[0070] This method may be applied to a method in which two articles are connected with a threaded fastener. A portion of the threaded fastener is coated with the first coating, which preferably includes a wax, then the threaded fastener is attached to a first article. A second coating is applied to the first article and fastener, for example by an electrodeposition coating process, but the second coating does not coat the portion coated with the first coating. Finally, a second article is connected to the first article with the threaded fastener. The first coating may be thermoset. Among suitable thermoset coatings containing a wax are epoxy coatings. One preferred epoxy coating contains a phenoxy resin, which may be thermoplastic or thermoset. The first coating may have a particulate surface component, which may be micronized polyethylene or another low surface tension material that aids in preventing the first coating from being coated by the second coating. It is preferred for the coating to contain both polyethylene and polytetrafluoroethylene, for example in the relative amounts described above. Such coatings as these can be expected to be abrasion resistant. Thus, the coating on the fastener will not be substantially scraped off of the fastener during critical periods of the fabrication process. The fastener may be weldable, as the fasteners illustrated in the Figures.
[0071] A vehicle, such as an automotive vehicle, may be assembled by including these method steps. At least a portion of a weldable fastener may be coated with a first coating composition before the fastener is welded to a vehicle component. The coating composition includes a component that provides the coating with a surface tension of up to about 30 mNm −1 . The vehicle component is then coated by electrodeposition coating. Because of the first coating, the electrodeposition coating does not substantially adhere onto the portion of the fastener with the first coating. By this we mean that the either no electrodeposition coating covers the portion or that any minor amount that might impinge on the portion can be easily removed, e.g. by brushing or knocking it off.
[0072] The first coating may be applied as an aqueous coating composition, which would generally contain a minor amount, for example from about 1% to about 40% by weight, of the component that provides the coating with a surface tension of up to about 30 mNm −1 . Polymeric materials for providing the desired surface tension have been described; preferably the component includes a wax, such as polyethylene wax, and/or polytetrafluoroethylene.
[0073] In another embodiment of the present invention, a method of improving the torqueing of a second fastener onto a first fastener. The first fastener is coupled to a body and is coated with an electro-deposition paint. The method contains the steps of: a) coating a portion of the first fastener with epoxy, preferably comprising a phenoxy resin, and a wax, particularly a polyethylene wax; b) fastening the fastener body; c) coating the body with electro-deposition paint, wherein the coating functions to resist the electro-deposition paint; and coupling a second fastener onto the first fastener. The portion of the first fastener that is coated is a portion that interfaces with the second fastener during the coupling. The interfacing portion may be, for example, a portion of the first fastener body or a portion of the first fastener that is a threaded region. The coating makes it possible to couple the fasteners by applying a torque to the second fastener with a variation in torque less than 36 Nm, preferably less than 30 Nm. This smooth application of torque is particularly advantageous when the second fastener is coupled using the automated power tools typical of automotive assembly practices. The coating typically provides a surface tension of less than 36 mNm −1 to the coated portion. The binder portion of the coating may further include a thermoplastic resin, such as ABS or PVC, as mentioned above. In some instances, it is advantageous for the wax to include polytetrafluoroethylene. The first fastener may be welded to the body, as when a cage of the first fastener is welded to the body.
[0074] The coating compositions preferably contain from about 15% to about 35%, preferably between about 20% and about 30% epoxy resin. In a non-limiting example, the coating composition contains about 26% by weight epoxy resin. In one embodiment, a coating composition is provided according to the present invention that forms a wax-rich surface.
[0075] FIG. 7 represents a chart depicting the torque in Nm required to couple a nut onto a coated threaded stud. Plots c 1 through c 4 represent the torque required to couple a nut onto a threaded stud coated with the coating according to the teachings of the present invention and subsequently coated with an electrodeposition paint. Plots e 1 through e 4 represent the torque required to couple a nut onto a threaded stud having an electrodeposition coating.
[0076] As can clearly be seen from the plots, those studs having electrodeposition coatings require significantly varying torque loads to couple the fasteners. As commercial fastener systems measure the torque load applied to the fastener to determine when a predetermined clamp load is reached, variations in the applied torque loads lead to corresponding undesirable variations in clamp load of a fastened joint. By reducing variation in the torque load, better fastening of joints can be accomplished.
[0077] As can be seen in Plot c 1 through c 4 , those studs having the coating layer according to the teachings of the present invention require significantly smoother torque loads to couple with a threaded fastener. Generally, those torque loads are lower than those of the e-coated fasteners e 1 -e 4 .
[0078] The variations in torque load are caused by marring and gauling of the e-coat layers between the threads. Variations of the torque are shown to reach greater than 30 Nm and even shown to be greater than 36 Nm when measured at intervals of 0.0075 seconds. As such, the coatings of the present invention are configured to provide variations of torque of less than 35 Nm, and preferably less than 30 Nm, and preferably less than 10 Nm, and most preferably less than 5 Nm when measured at 0.0075 second intervals.
[0079] One advantage of the coating compositions of the invention is that when they are applied to the surface to be coated, the coatings can withstand the harsh conditions and high temperatures associated with welding a coated part to a metal plate or other part of the assembly. For example, to attach a weld stud to a metal plate requires that at least the metal at the end of the stud in contact with the metal plate be heated to a temperature sufficient to melt the metal. Because the stud is generally made from a material that conducts heat, it is to be expected that during the welding process the weld stud as a whole is heated, including the layer of the stud directly below the organic coating of the invention. Nevertheless, the coating compositions of the invention provide an adequate coating that survives even the harsh welding conditions. In a subsequent step, the coatings of the invention adhering to the weld stud or other threaded fasteners of the invention act to prevent undesired deposition of electrocoat compositions in a subsequent electrodeposition step. | 4y
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FIELD OF THE INVENTION
The invention relates to measuring devices particularly those which are uniquely adapted to the construction field. Reference is made to United States Patent Office Disclosure Document No. 408898, filed by the Inventor on Nov. 7, 1996.
BACKGROUND OF THE INVENTION
Subsequent to the laying of a building foundation, one of the critical construction tasks is the positioning of a sill or foundation member about the periphery of the building location. Frequently these sill members are wooden and of standard sizes. The foundation will normally be adapted with a series of upright fastening members. These upright fastening members (such as lag bolts) will be about the periphery and will not be precisely measured but will be within the desired sill width. The task then is to drill holes in the sill members which will precisely receive the upright fastening members.
The construction worker is then confronted with the task of making precise measurements of the distance that each of these upright members is from the edge of the foundation and then making a similar measurement onto the desired sill in order to drill the hole at the precise location in the desired sill. Since there will be several uprights receiving holes along the length of a given sill, these measurements are very critical. If any one of them is more than slightly off, a sill member could be wasted. Sill members are normally strong, thick, and expensive. Waste of them is particularly undesirable.
Additionally, the act of having to make precise measurements in two different places (from upright to foundation edge and from sill edge to hole) is also a time consuming effort. It would be advantageous to both reduce the amount of time required for this task as well as to improve on the accuracy of the measurement.
Relating to the application of building components or substructure to foundations, the contracting industry has from time to time developed special purpose tools to deal with specific contingencies. For example, in U.S. Pat. No. 4,580,926, issued to Bunnell, on Apr. 8, 1986, a foundation level and orientation tool was developed for use with underground oil wells in order to assist in leveling the foundation of a sub-sea structure. Additionally, in U.S. Pat. No. 5,177,917, issued to Haucke, on Jan. 12, 1993, the inventor developed a vertical building construction section which enabled standard dimension lumber and plywood sheets that is both faster and avoided "stick" construction.
As critical as the task seems, the Inventor is aware of no previous apparatus or method which have been developed in order to assist in positioning the sill member of a building to its foundation.
What would be helpful then would be an apparatus and method of making such measurements quickly, efficiently, and in a very accurate manner so as to save time and the expense of material costs.
SUMMARY OF THE INVENTION
The Inventor has solved the problems inherent in the above related art by developing a slotted slide tool which assists in making these measurements. By positioning the sill along the edge of the foundation and aligning the tool with the outward edge of the sill, the sliding slot can be used to both locate the position of the upright and mark onto the sill where the desired hole needs to be drilled.
It is then an object of the present invention to provide a more effective means of positioning holes in sills to receive the uprights from a building foundation.
It is a further object of the present invention to provide a sliding tool which is capable of assisting in the construction task of positioning upright receiving holes in building foundation members or sills.
It is a further object of the present invention to provide such a measuring device which may be quickly and accurately used with a given sill.
It is a further object of the present invention to provide such an upright positioning tool which may be used with sills of more than one width.
Other features and advantages of the present invention will be apparent from the following description in which the preferred embodiments have been set forth in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In describing the preferred embodiments of the invention reference will be made to the series of figures and drawings briefly described below.
FIG. 1 is an oblique view of the present invention demonstrating each of the parts in their functional relationship.
FIG. 2 is an isolated view of a sliding slotted member.
FIG. 3 depicts the receiving member with the slots for receiving the sliding member.
FIG. 4 depicts a side view of the apparatus as positioned to measure an upright member.
FIG. 5 depicts a top view of the apparatus as positioned to measure an upright member.
FIGS. 6A, 6B, and 6C depict alternative sliding structures.
While certain drawings have been provided in order to teach the principles and operation of the present invention, it should be understood that, in the detailed description which follows, reference may be made to components or apparatus which are not included in the drawings. Such components and apparatus should be considered as part of the description, even if not included in such a drawing. Likewise, the drawings may include an element, structure, or mechanism which is not described in the textual description of the invention which follows. The invention and description should also be understood to include such a mechanism, component, or element which is depicted in the drawing but not specifically described.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. While the invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention defined in the appended claims.
Making reference first to FIG. 1, the principal components of the sliding positioning tool (10) can be seen. A sliding member (20) is adapted with an elongated slot (21) through the length of its midsection. The length (22) of the slot corresponds precisely with the width of a sill (not depicted in FIG. 1) which is to be placed upon a foundation (not depicted in FIG. 1). The width (23) of the slot (21) is adapted to receive an upright member, such as a lag bolt (also not depicted in FIG. 1).
The ends (25) of the slot (21) may be arced so as to aid in centering or otherwise positioning the outline of a lag bolt (not depicted in FIG. 1). FIG. 2 depicts this sliding member (20) in isolation, still without the sill, foundation, and upright members which will be shown and described later.
Also depicted in FIGS. 1 and 3 are the slide receiving member (30). The slide receiving member (30) is adapted with a back side (31) which is further adapted with a positioning plate (32) whose plane is perpendicular with the length of a slide receiving plate (33). The slide receiving plate (33) is also adapted with an elongated slot (34) which will be of equal width and will, along its length, slide along the position of the sliding member slot (21). In other words, it is also of sufficient width to receive an upright sill stabilizing member (not depicted in FIGS. 1, 2, or 3). When the sliding member slot (21) is positioned above or below the slide receiving slot (34), together they form a single slot, as will be more clearly seen in FIG. 5.
The slide receiving plate (33) is also adapted with slide receiving channels (35) along its sides (36). Such slots (21, 34) allow the sliding member (20) to be snugly received within the channels (35) and to remain in stable lengthwise position with the slide receiving member (32) as the sliding member (20) is slid back and forth along the slide receiving plate (32). In this manner it can be seen that the slots (21, 34) together form a single open slot. The slide receiving member is positioned in isolation in FIG. 3.
FIG. 4 is a side view of the apparatus as positioned along a sill and over an upright lag bolt (60). It can be seen that the perpendicular positioning plate (31) rests firmly against the outer edge (41) of a sill (40) which is positioned along the outer edge (51) of the building foundation (50). It can also be seen that when positioned for use, the upright fastening member (such as a lag bolt (60)) protrudes up through the described slots (21, 34) to the measuring device (10).
Making reference to FIG. 5, it can be seen that the sliding slot (21) can be slid to a point where its outer end (26) makes contact with an upright foundation member, such as a lag bolt (60). The inner end (27) of the sliding slot will now be positioned over the sill member (40) at a point which is precisely where a hole (42) will need to be drilled to receive the upright member (60) when it is placed into position over the foundation (50) edge with the foundation edge (51) aligned with the sill edge (41). FIGS. 4 and 5 depict side and top views of this process.
As presently described, it is necessary to have a different tool for each potential sill width. This is because the sliding slot is made of a length to precisely correspond with one such sill width. Making reference to FIG. 6, however, it is shown that it is possible, however, to provide a sliding slot (71) which is marked with two or perhaps three different locations (72, 73, 74) in order to correspond with various sill widths (such as 4", 6", and 8"). In this case the construction task requires an informed decision to be made by the workman, namely to ensure that the sill is marked according to the correct sill width mark on the sliding slot. This does offer the advantage, however, of allowing a single tool to be used for a construction job which may involve sills of varying widths.
Additionally, there may be other specific structures or combinations of slide members and slide receiving members which will accomplish the task of positioning a sliding slot and a stationary slot one on top of the other. For instance, it is possible that the sliding slot could be below the stationary slide receiving slot.
Additionally, the two could be positioned together by means other than the edge receiving slots depicted in the present invention. For instance, elongated slots could be positioned on either side of the positioning slot which could be used to keep the sliding member and the slide receiving member precisely aligned as the sliding member is slid against the slide receiving member. Theoretically, the invention could be successfully practiced with no mechanism which would physically hold the two members against one another and a construction worker could successfully practice the invention by simply manually positioning the sliding slot precisely above the slide receiving slot. This would, however, clearly be a more cumbersome and less efficient and effective way to accomplish the task. It is worth noting, however, because it demonstrates that the particular means and manner of positioning the two against one another is not crucial to the practice of the invention.
In addition to the exposed sliding channel described and depicted above, for instance, a base member could be adapted with an enclosed planar cavity through which a sliding member could be completely contained and slid back and forth therethrough. Additionally, instead of channel which runs the entire length of the base member, the base member could be adapted with three or four retaining members along its length, so long as the number and strength of such retaining members was sufficient to snugly hold the sliding member in relative position with the base member. It is not the purpose and focus of this invention to teach other means of holding planar members in relative sliding position, but rather to teach the process of expediting the measuring and positioning of upright receiving holes in foundational sill members. FIGS. 6A, 6B, and 6C depict these alternative forms.
Further modification and variation can be made to the disclosed embodiments without departing from the subject and spirit of the invention as defined in the following claims. Such modifications and variations, as included within the scope of these claims, are meant to be considered part of the invention as described. | 4y
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CROSS-REFERENCE TO RELATED APPLICATION
The present application claims priority to U.S. Provisional Patent Application Ser. No. 60/311,168 filed on Aug. 9, 2001.
BACKGROUND
1. Field of the Invention
This invention relates to protective covering and restraining devices for user equipment which are suspended by a neckstrap positionable about the neck, and specifically relates to a protective covering structured to allow the user equipment, such as binoculars or a camera, to be restrained against the user until ready for use.
2. Background of the Invention
There are many different types of protective and restraining devices designed for use with neckstrap- or harness-suspended equipment. Some prior art devices serve to hold the user equipment in place against the user's body, while others have been developed to solely protect the user equipment from being damaged by exposure to the elements (i.e., sun and rain). Prior art devices have been developed to serve both the purposes of restraining and protecting the user equipment. Such devices are often complicated and expensive, however.
Harness type devices keep user equipment weight off the user's neck by applying at least some equipment weight to both shoulders of the user, but are very inconvenient to use when the user changes, for example, from wearing heavy outer clothing to lighter clothing, or vise versa. Harness devices also tend to be expensive and complicated to use. Devices for use with neckstrap-suspended equipment are easy and comfortable to use when the user is wearing heavy outer clothing, but when the user wears lighter clothing the weight applied to the user's neck is uncomfortable.
The Quick Release™, a harness-type mechanism marketed by Sunrise Creations, is an example of a complicated device which only provides restraint to the user equipment, not protection. The device comprises straps which engage the user device and extend over the shoulders and a strap which goes around the chest. A third strap secures the shoulder straps to the chest strap. The chest strap is constructed with hook and loop tabs which hold the user equipment firmly in place against the user's body. This requires extra attachments to the user equipment and makes it much more cumbersome and inconvenient to use when the user needs to remove or add outer clothing.
U.S. Pat. RE37,155E discloses a device similar to the present invention for securing the user equipment in place against the user's body and protecting the equipment while secured in place. That invention, however, cannot remove all weight from the user's neck like the present invention. The patent discloses a protective covering for the user equipment which is strapped about the user's abdomen. The protective covering holds neckstrap-suspended user equipment against the user's body preventing it from moving about or swinging away from the body. It does, however, allow the neckstrap of the user equipment to hang loose, leaving open the possibility that the neckstrap could slide off of the neck of the user. More importantly, the body-encircling strap which holds the protective cover in place against the user's abdomen may slip down the body causing some degree of inconvenience to the user.
Therefore, it would be advantageous in the art to provide a device which can be used to allow user equipment to hang from a neckstrap in a secure, protected manner and that can keep equipment weight off the user's neck without the use of a separate harness in a simple, secure, protected manner. It would also be advantageous to provide a device which can be easily and quickly changed from an around-the-neck, harness-type orientation to an over-the-shoulder arrangement in which the equipment is secured to the user's body proximate the user's hip. Moreover, it would be advantageous to provide a device which is structured to facilitate easy removal of the device away from the user's body and easy placement against the user's body.
SUMMARY OF THE INVENTION
The present invention provides an equipment cover and restraining device to be worn by a user when carrying such equipment as a pair of binoculars, a still or video camera, a water bottle or other device that is typically carried by a user when hiking, walking or engaging in other activities. Thus, the equipment cover can be modified or configured to fit a particular piece of equipment. The equipment cover and carrying device of the present invention substantially prevents the equipment secured thereby from swinging as the user moves by holding the equipment against the user's body. Moreover, the present invention comfortably distributes the weight of the equipment and makes it quickly and easily accessible.
An important feature of the present invention is the ability to quickly and easily change the configuration of the equipment harness from a neck-type harness system in which the equipment is positioned in front of the user's torso (e.g., the chest or waist) to an over-the-shoulder system in which the equipment is positioned proximate the side of the user under the arm or proximate the hip. The configuration of the harness system is easily adjustable to any user regardless of size.
The harness system of the present invention is also relatively inexpensive to manufacture, is non-product specific, and can be made out of a wide variety of materials. Moreover, the present invention is easy to use and can be used while doing many activities. Furthermore, the present invention can be used with many different types of clothing, is very quiet to use, is easily stowed away when not in use, is lightweight, and provides neckstrap-suspended equipment protection from rain, dust, and damage due to impact.
The harness system of the present invention is configured to restrain and protect neckstrap-suspended user equipment in a non-swinging covered manner. The harness system comprises a neckstrap for positioning about the neck of a person with an opening or connecting device located near a mid-point of the neckstrap. The neckstrap is connected to the piece of user equipment. A protective covering for enclosing the equipment suspending from said neckstrap is attached to a body-encircling band or strap. The body-encircling strap may be detachably attached to the covering. In addition, the body-encircling strap can be threaded through the opening or coupled to the connecting device of the neckstrap.
When the neckstrap is worn about the neck of the user, with the user equipment suspended from the neckstrap and in front of the user, the body-encircling strap can be coupled to the neckstrap at the midpoint of the neckstrap to pull the neckstrap away from the back of the neck of the user. The body-encircling strap which is connected to the cover holds the cover and thus the equipment against the body of the user while the interconnection between the neckstrap and body-encircling strap places the weight of the user equipment at a much more comfortable position, on the shoulders of the user and away from the neck.
The cover may be made of a flexible material so as to form around the equipment or a customized rigid cover for fitting around a particularly configured piece of equipment. In the case of a flexible cover, an elastomeric or elastic material that has longitudinal elastic properties may be attached around a perimeter of the cover so as to form a pouch for receiving the equipment therein, the elastic material employed to at least partially close the cover around the equipment and hold the cover to the equipment. The opening formed by the elastic material, is positioned to the back of the cover and against the user's body, such that the cover provides protection to the equipment on the exposed surfaces.
In one embodiment, the coupling device comprises a ring coupled to the neckstrap such that the neckstrap is formed from two lengths of material, each attached between the ring and the user equipment. The body-encircling band can then be looped through the ring to form a harness for supporting and maintaining the user equipment relative to the body of the user.
By removing the body-encircling band from engagement with the ring, the neckstrap can be worn over one shoulder of the user with the cover positioned proximate the side opposite the one shoulder of the user.
The neckstrap and body-encircling band can be made to interconnect proximate a midpoint of the neckstrap by any means known in the art.
In another embodiment, the body-encircling band is releaseably connected to said cover so as to allow the cover to stay on the user equipment during use by the user.
In yet another embodiment, the cover configured to be removed from the user equipment in order to release the equipment from the cover and thus the body-encircling band. Thus, once the equipment is removed, the cover remains attached to the body-encircling band while the user equipment is only retained relative to the user by the neckstrap.
In still another embodiment, the neckstrap is configured to be selectively lengthenable between a first length for positioning around the neck of a user and a second length for positioning over one shoulder of the user. To facilitate ease of adjustment, the neckstrap may be formed from a longitudinally elastic material or have a portion formed therein for providing longitudinal elasticity.
The harness system of the present invention may be employed for use with various types of user equipment including without limitation a pair of binoculars, a still camera, a video camera, a water bottle, a spotting scope, and a range finder.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a back view of first embodiment of a device for protecting and supporting neckstrap-suspended user equipment in accordance with the principles of the present invention;
FIG. 2 is a front view of a second embodiment of a device for protecting and supporting neckstrap-suspended user equipment attached to a user in accordance with the principles of the present invention;
FIG. 3 is back view of the device for protecting and supporting neckstrap-suspended user equipment shown in FIG. 2 ;
FIG. 4 is another front view of the device for protecting and supporting neckstrap-suspended user equipment shown in FIG. 2 ;
FIG. 5 is a back view of the device shown in FIGS. 2 , 3 and 4 in an alternative configuration;
FIG. 6 is a back view of a second embodiment of a means for interconnecting the first and second straps of a harness system in accordance with the principles of the present invention;
FIG. 7 is a back view of a third embodiment of a means for interconnecting the first and second straps of a harness system in accordance with the principles of the present invention;
FIG. 8 is a back view of a third embodiment of a device for protecting and supporting neckstrap-suspended user equipment attached to a backpack in accordance with the principles of the present invention; and
FIG. 9 is a back view of the device shown in FIGS. 2 , 3 , 4 and 5 in yet another alternative configuration.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, a device for protecting and supporting neckstrap-suspended user equipment is provided which comprises a body-encircling strap or band, a protective covering for housing the user equipment, and a neckstrap structured to engage the user equipment and also structured to allow lacing engagement or otherwise engage the body-encircling strap to facilitate easy attachment and removal of the device from the user's body. The present invention provides a means of supporting and protecting the user equipment while allowing ease of access and use while not encumbering the equipment.
Referring now to the drawings, FIG. 1 illustrates a back view of a harness system, generally indicated at 1 , for restraining and protecting a piece of equipment 2 , in this case a pair of binoculars, relative to the body of a user wearing the harness system 1 . The harness system 1 is generally comprised of a first strap 3 configured to fit around the neck of a user and a second strap 4 configured to encircle or otherwise extend around a substantial portion of the torso of a user. The first strap 3 is comprised of a first strap portion 3 ′ and a second strap portion 3 ″ of approximately equal length. Interposed between the first and second strap portions 3 ′ and 3 ″ is a coupling or interconnecting device 5 to which the first and second strap portions 3 ′ and 3 ″ are attached. In this example, the coupling device 5 is comprised of a single ring member about which the proximate ends of the first and second strap portions 3 ′ and 3 ″ are attached as by overlapping the ring member and attaching the ends back upon the strap portions 3 ′ and 3 ″ as by sewing or adhesively attaching as shown. The free or terminal ends of the strap 3 are coupled to the user equipment 2 as with hooks or clasps 7 that are configured to attach to the equipment 2 .
The second strap 4 is attached to a protective cover 8 that is configured to fit around at least a portion of the equipment 2 . The cover 8 includes an elasticized opening 9 to help maintain the cover 8 on the equipment 2 . The opening 9 is positioned against the user when the harness system 1 is worn so that the majority of exposed surfaces of the equipment 2 is protected by the cover 8 .
The second strap 4 is fixedly attached to the cover 8 at one end and releaseably attached to the cover 8 at a second end as with a buckling mechanism 11 comprised of interconnecting buckling members 11 ′ and 11 ″. The engagement of the strap 4 with the buckling member 11 ″ allows the effective length of the strap 4 to be easily adjusted by pulling the strap 4 through the buckling member 11 ″.
To form a harness system about a user, the second strap 4 is threaded through the ring member 5 and the buckling members 11 ′ and 11 ″ are connected. When the buckling members 11 ′ and 11 ″ are connected, the cover 8 is then secured against the body of the user and the strap portions 3 ′ and 3 ″ are positioned over the shoulders of the user. The interconnection of the strap 4 with the ring member 5 causes the strap members 3 ′ and 3 ″ to be pulled down the user's back and away from the user's neck, thus relieving pressure that would otherwise be caused by the weight of the equipment from the neck of the user.
FIGS. 2 and 3 show a front view and a back view, respectively, of a person upon whom a restraining and protective device, generally indicated at 10 , of the present invention is positioned. The device 10 comprises a neckstrap 12 for positioning about the neck of the user. The neckstrap 12 has a selected length and an opening 22 located near a mid-point of the selected length, as specifically shown in FIG. 3 . The opening 22 may be provided in the form of a ring or other similar device or may be an opening formed in the fabric or material of the neckstrap 12 .
It is also contemplated that a plurality of rings 22 may be employed. For example, a pair of spaced apart rings along the length of the neckstrap 12 may be utilized with the body-encircling strap threaded through both rings 22 to have a similar effect as when employing a single ring 22 , as illustrated.
As illustrated, the opening 22 is comprised of a ring, which may be formed of plastic or other suitable material with the neckstrap 12 comprised of two separate lengths of material 12 ′ and 12 ″ connected at their ends to the ring 22 . The components 12 ′ and 12 ″ of the neckstrap are of equal length so as to have the ring 22 attached proximate the midpoint of the entire length of the neckstrap 12 . The neckstrap 12 has two terminal or free ends 23 and 25 at opposing extremities of its length and attachment mechanisms 24 , 26 are located at each terminal end. The attachment mechanisms 24 , 26 provide for attachment of the user equipment 30 to the neckstrap 12 , as further illustrated in FIG. 4 . The neckstrap 12 may be structured to permit adjustment of the length thereof.
The device 10 of the present invention further comprises a body-encircling strap 16 which is sized to adjustably fit about a user's body. The body-encircling strap 16 may be comprised of a longitudinally elastic material so as to allow the strap 16 to stretch and provide some resiliency and longitudinal stretching of the device 10 to provide a tight fit of the strap 16 to the user without unwanted constriction. The strap has two opposing terminal ends 32 , 34 , shown in phantom in FIG. 2 , which secure in some fashion to a protective covering 18 . One of the terminals ends 32 , 34 may be permanently secured to the protective covering 18 by, for example, stitching. The other terminal end 32 , 34 is detachably attachable to the protective covering 18 to allow the user to position the body-encircling strap 16 about the user's body as shown. Alternatively, both terminal ends may be detachably attachable to the protective covering 18 .
The protective covering 18 consists of a single expanse of flexible material, preferably also being waterproof. However, any material having properties which produce a flexible water resistant cover could be used. FIG. 2 illustrates that the protective covering 18 has an outer extremity 14 (shown in phantom) which, preferably, has an elastomeric material secured in proximity thereto. For example, the outer extremity 14 of the protective covering 18 may be formed with a casing through which a length of elastic material is positioned to cause the outer extremity 14 to gather inwardly toward itself, thereby forming a pocket 36 . The protective covering 18 , therefore, has an expandable opening. The protective covering 18 is of sufficient size or dimension to allow for the covering of approximately 98% of all neckstrap-suspended equipment surfaces oriented away from the user's body. The protective covering 18 holds the user equipment firmly against the user preventing it from moving or being damaged.
In use, the user attaches one end of the flexible band 16 to the protective covering 18 if the device 10 is of an embodiment where both terminal ends 32 , 34 are detachably attached to the protective covering 18 . The free terminal end 32 , 34 is then threaded through the opening 22 in the neckstrap 12 as shown in FIG. 3 . The user then encircles his body with the flexible strap 16 and attaches the free terminal end 32 , 34 to the protective covering 18 . The ends of the neckstrap 12 bearing attachment mechanisms 24 , 26 are then brought over the shoulders of the user and the attachment mechanisms 24 , 26 are attached to the user equipment 30 . The user equipment 30 is then placed in the protective covering 18 by increasing the size of the elasticized opening of the protective cover 18 to accommodate the size of the user equipment 30 . For example, a pair of neckstrap-suspended binoculars is protected and restrained from movement by first stretching the outer extremity 14 of the cover 18 around and over the lower portion of the suspended binoculars which covers the lenses facing down. Next, the protective covering 18 is stretched up, over, and around the upper portion of the suspended binoculars covering the lenses facing up. The device 10 of the present invention may also be placed on the user's body by attaching the user equipment 30 to the neckstrap 12 as previously described, threading the body-encircling band 16 through the opening 22 , placing the neckstrap about the user's neck and securing the body-encircling band 16 in place about the user's body. The user equipment 30 is then positioned in the protective covering 18 as previously described.
Due to the elastomeric action of the protective covering 18 and the elastic outer extremity 14 of the protective covering 18 , the device 10 is kept in position to cover nearly all outwardly oriented surfaces of the user equipment 30 . The only surfaces of the binoculars 30 not covered are those which are oriented against the user and small areas near the neckstrap 12 attachment mechanisms 24 , 26 .
As further illustrated in FIG. 5 , the device 10 can be selectively reoriented by the user 40 to fit over one shoulder 42 of the user with the user equipment 30 and cover 18 positioned at the side 44 of the user 40 opposite the one shoulder 42 . To do so, the body-encircling strap 16 is removed from engagement with the ring 22 and the neckstrap 12 is moved into position over one shoulder. If needed, the neckstrap 12 is adjustable in length to provide proper fit when changing device configurations. In such an orientation, the neckstrap 12 supports the weight of the user equipment 30 relative to the user while the body-encircling strap 16 holds the equipment 30 to the side 44 of the user 40 to significantly reduce bounding of the equipment 30 relative to the user 40 as a result of movement of the user 40 .
As shown in FIGS. 6 and 7 , various types of engagement may be utilized between the neckstrap and the body-encircling strap. For example, the neckstrap 50 shown in FIG. 6 may itself define an opening 52 therein proximate a midpoint of the neckstrap 50 . The body encircling strap 54 can then be threaded or laced through the opening 52 to provide the desired engagement in accordance with the principles of the present invention. Likewise, as shown in FIG. 7 , the neckstrap 60 may comprise a continuous section of material with an intermediate strap 62 coupled to the neckstrap 60 . A ring 64 is then attached to the opposite end of the intermediate strap for engaging the body encircling strap 66 . It is further contemplated in FIG. 8 that the neckstrap 70 may be coupled to a separate piece of clothing or user equipment, such as a backpack 72 . An engaging tab or hook 74 that is attached to the backpack 72 may be configured to engage a ring 76 coupled to the neckstrap 70 . In such a fashion, the midpoint of the neckstrap 70 is pulled away from the back of the neck of the user such that the weight supported by the neckstrap 70 is positioned on the shoulders of the user. Moreover, the position of the interconnection of the neckstrap 70 to the backpack 72 can be such that the neckstrap 70 lies on top of the shoulder straps 78 and 80 of the backpack, as such shoulder straps 78 and 80 are typically padded and would effectively provide padding to the neckstrap 70 .
As shown in FIG. 9 , the harness system 100 in accordance with the present invention may be worn with the neckstrap 102 positioned about the neck of the user and the body-encircling strap 104 positioned about the torso of the user without direct engagement between the two straps 102 and 104 .
It is further contemplated that the body-encircling strap may be configured to be selectively removable from the cover. It is often the case that certain user neck-supported equipment comes with its own protective cover that is contoured to the equipment and allows use of the equipment without requiring removal of the cover during use. As such, the body-encircling strap may be a continuous strap with an attachment mechanism such as a combination of hook and loop fastener between the strap and the cover to allow for easy and selective removal of the cover, and thus the equipment contained therein, from the body-encircling strap. It is also contemplated that snaps or other quick release fasteners known in the art may be utilized, such as the buckle 11 shown in FIG. 1 .
The present device aids in preventing the loss or damage of neckstrap-suspended user equipment. The user equipment is also prevented from swinging when the user is in motion. The present device allows the user equipment to be easily removed from the cover in order to be used. The present invention also allows the device to be easily positioned on and removed from the user. Most importantly, the configuration of the present invention allows the device to be more securely positioned on the user's body and prevents the neckstrap from weighing on the user's neck.
It is to be understood that the above-described embodiments are only illustrative of the application of the principles of the present invention. Numerous modifications and alternatives may be devised by those skilled in the art, including combinations of the various embodiments, without departing from the spirit and scope of the present invention. The appended claims are intended to cover such modifications, alternative arrangements, and combinations. | 4y
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CROSS REFERENCE TO RELATED APPLICATIONS
[1] 1. This application is a continuation-in-part of my co-pending application Ser. No. 09/173,897 filed on Oct. 16, 1998.
BACKGROUND OF THE INVENTION
[2] 2. This invention relates to the formulation and configuration of a heat reactive resin system at temperatures below the melting temperature (T m ) of the base resin in the system. More particularly the invention relates to the preparation of coating powders, the application of coatings and the formation of shapes from fluid heat reactive resin systems and curing them at low temperatures.
[3] 3. 1. Definitions
[4] 4. As used in the specification and the attached claims, the following terms are defined as follows.
[5] 5. a. “Base resin” or the unmodified term “resin,” means a neat, heat reactive resin to which no curing agents have been added.
[6] 6. b. “Resin mixture” means a simple mixture of resins and other ingredients such as curing agents, pigments, additives and the like before dispersing the other ingredients in resins.
[7] 7. b. “Normally solid” is used in the context of ambient room conditions.
[8] 8. c. “Heat reactive resin systems” means resins in which curing agents, catalysts, pigments, additives, fillers and the like have been dispersed.
[9] 9. d. “Slowly,” when used to modify how the pressure in a pressure vessel is relieved, indicates that the pressure is relieved in a controlled manner that avoids a significant formation of a foam.
[10] 10. e. “Transient processing time” is the elapsed time that a heat reactive resin system discharged from a pressure vessel remains fluid enough to be configured.
[11] 11. f. “Low temperature curing” means the cure of a heat reactive resin system is carried out at a temperature below about 140°C.
[12] 12. g. “Supercritical range” means the conditions of temperatures and pressures at which liquefiable gases are approaching, at or somewhat above their supercritical point. Note that this is consistent with prior usage as illustrated, for example, with the definition of “supercritical fluid” as used in U.S. Pat. No. 5,027,742 at line 23 of column 4, the teachings of which patent are incorporated herein by reference as they relate to liquefiable gases and supercritical fluids.
[13] 13. 2. Prior Art Discussion
[14] 14. Commercially important materials such as paints, adhesives, molding compounds, coating powders, toners, pharmaceuticals are commonly prepared from polymers in which curing agents, pigments, fillers and the like are dispersed. The dispersions may prepared in liquid dispersing equipment such as ball mills, media or bead mills, and in high shear mixers such as a Cowles dissolver, colloid mills and the like while the polymers are dissolved in a solvent. Dispersion processes are normally carried out at atmospheric temperatures and pressures.
[15] 15. If the solid ingredients are dispersed in polymers such as rubber, plastics or resins, the polymers are processed in a plastic or molten state. Typical apparatuses for carrying out such dispersions are Banbury Mixers, 2-roll mills and extruders of all types. In these devices the polymer is heated above its softening temperature by external heating, by frictional heating of the plastic mass, or by the dissipation of mechanical action (work.) Even low melting resins such as those used in the preparation of thermosetting coating powders or electrostatic toners, require processing temperatures of at least about 100°C. and most usually significantly higher temperatures. If the curative in the thermosetting resin systems are designed for low temperature curing, they are, at least, partially reactive at the normal extrusion temperatures e.g. 100°C. or more.
[16] 16. Thermosetting polymer mixtures are conventionally prepared by thoroughly dry mixing resinous binders with components such as curing agents, additives, pigments, fillers, catalysts, etc. and then dispersing the ingredients above the melting point of the resinous binders. This is commonly referred to as “melt mixing.” A description and examples of melt mixing can be found in the Kirk-Othmer Encyclopedia of Chemical Technology, Volume 6, starting on page 635 (1993).
[17] 17. In the preparation of heat reactive thermosetting resin systems such as are useful as coating powders, adhesives and the like, it is often desirable to formulate reactive resin systems that cure at relatively low temperatures or rapidly at higher temperatures. Care must be taken when the reactive resins mixtures are dispersed above their melting points to avoid premature reactions that yield gelled or partially gelled products. Even if premature reactions do not result in partially gelled products, the curing reaction, once started, may continue at ambient temperatures resulting in cross linking reactions and reduced flow of the dispersions when used in coating processes. Eventually, the reaction will proceed until the flow is impaired to the extent that a continuous film can no longer be formed. The ability of a thermosetting composition to maintain good application characteristics over a long period of storage is referred to as “storage stability” or sometimes “shelf life.”
[18] 18. There are many applications where powder coatings cannot be used because of the high temperatures required to melt and cure the coating in a reasonable time, e.g. 30 minutes or so. Most of these applications involve coating temperature sensitive substrates such as plastics, various types of wood or engineered wood products such as particle board, oriented strand board (OSB) and medium density fiberboard (MDF) and composite assemblies containing rubber, plastics electrical insulation, etc. In order to utilize reactive curing agents necessary for low temperature curing thermosetting coatings, it is necessary to process them at temperatures below which significant reaction between the resin and the curative occurs.
[19] 19. Melt mixing processes are made more difficult if the resins have significantly differing melting points and variations in melt viscosity. Melt mixing temperatures must be sufficiently high to melt the resin and form a useful and processable melt viscosity but, on the other hand, the temperatures must not be so high as to lower the viscosity of additives to a point at which good dispersions can not be achieved. That is to say that melt mixing is most effective when the viscosities of the melted materials are of a similar magnitude. For example, when melt mixing or dispersing crystalline or partially crystalline resins, additives, catalysts, waxes, etc. with amorphous polymers, the lack of homogeneity of the melt viscosities can result in micro defects in coatings applied from the dispersion. Micro defects lead to haze and loss of clarity. This can diminish the utility of coating materials in demanding applications such as automotive finishes in which a high level of gloss and distinctiveness of image are highly desired.
[20] 20. Gaseous fluids are commonly used in extraction and impregnation processes. Exemplary of this technology are U.S. Pat. Nos. 3,969,196, 4,061,566, 4,308,200 and others.
[21] 21. In U.S. Pat. No. 4,598,006, thermoplastic polymers are impregnated with fragrances, pest control agents and pharmaceuticals dissolved in a volatile swelling agent for the polymer, where the volatile swelling agent is a gas maintained above or near supercritical conditions. When the pressure or temperature is reduced, the gas diffuses out of the thermoplastic polymer but the impregnated material remains in the polymer. The reduction in temperature or pressure is carried out carefully so the physical appearance of the polymer is not altered.
[22] 22. U.S. Pat. No. 4,820,752 discloses a method of infusing an additive into a polymer using a compressed fluid which is normally a gas at room temperature. The fluid may be in a liquid or gaseous state if the operating environment at which the process is being carried out is below or equal to the critical temperature of the fluid. If the operating environment is above the critical temperature of the fluid, the process must be carried out in the liquid state. The fluid and the additive are chosen so that the additive has a degree of solubility in the polymer into which it is to be infused and so that the solution of fluid and additive has a degree of solubility in the polymer and is capable of swelling the polymer. The polymer is swollen at least 2% by volume and preferably 5% by volume by the compressed normally gaseous fluid used. Carbon dioxide is the preferred fluid.
[23] 23. In both of these patents, the form and appearance of the polymer is not significantly altered but the additive must be soluble in the supercritical fluid. If the additive is not soluble in the supercritical fluid, it cannot be imbibed by, or carried into, the structure of the polymer. For a more complete description of the solvation of resins in supercritical fluids, see U.S. Pat. No. 4,734,227 whose teachings are incorporated herein by reference.
[24] 24. U.S. Pat. No. 5,708,039 describes a method for producing a coating powder by dissolving the ingredients in a combination of an active solvent and supercritical carbon dioxide. The solution is sprayed from the supercritical solution which reportedly forms generally spherical particles. The remaining solvent is subsequently removed by evaporation under vacuum.
[25] 25. The use of liquefied gasses in the supercritical state for processing resin mixtures is described in U.S. Pat. No. 5,399,597. Thermosetting resin mixtures are dispersed in a supercritical gas, preferably supercritical carbon dioxide, in a first pressure vessel. The dispersion process is carried out by agitating the resin mixture with the supercritical carbon dioxide until the desired degree of dispersion is obtained. The dispersion of thermosetting resin and supercritical carbon dioxide is then atomized through hydraulic spray nozzles into a second vessel maintained at a lower pressure. A conglomerate of flake-type and rounded particles is reported to be formed. Spraying the resin mixture and carbon dioxide directly from the supercritical state to form powder particles is a critical part of the patented process and must be observed in all cases. It is taught that none of the ingredients in the resin mixture should be soluble in the supercritical carbon dioxide to avoid volatilization (separation) when the resin mixture is sprayed from the supercritical state.
[26] 26. A process is disclosed in U.S. Pat. No. 5,975,874 for compounding thermosetting coating powders in an extruder. A supercritical fluid is utilized in the extruder to reduce the viscosity of a coating powder precursor although the patent does not discuss how the supercritical fluid is contained within the extruder. It is taught that coating powders are made from the extruded materials.
[27] 27. U.S. Pat. No. 5,981,696 is of interest for its disclosure of dissolving base resins and a plurality of hardeners in an inert low molecular weight compound while the compound is maintained above its critical temperature and pressure. The resins and hardeners are processed within a pressure vessel and, it is said, coating powders may be formed by spraying the solution into a region of lower pressure. Alternatively, the patent teaches that the pressure may be relieved in a time-dependent manner. In this later case, the reactor is described as containing a solid foam after a normal pressure is reached. The foam is described as consisting of individual particles which adhere to each other but which can be separated into individual particles.
OBJECTS OF THE INVENTION
[28] 28. It is an object of this invention to provide a method for compounding heat reactive resin systems at temperatures below the melting point of the base resins.
[29] 29. Another object of this invention is to enable the utilization of lower temperature curing agents which would be too reactive if compounded above the melting point of the base resin.
[30] 30. And yet another object of the invention is to utilize low melting, crystalline—or even liquid ingredients—in the formulation of fluid heat reactive resin systems that can be applied directly to a substrate and subsequently cured.
[31] 31. It is a further object of the invention to prepare a fluid heat reactive resin system that may be configured at ambient temperatures.
[32] 32. Still a further object of the invention is to compound heat reactive resins systems which can be cured at lower temperatures than can current resin systems compounded above the melting point of the base resin.
[33] 33. A further object of this invention is to provide a method for coating a substrate with a fluid heat reactive resin system directly upon discharge from the reactor vessel without first converting the resin system to a powder and subsequently applying the powder to the substrate.
[34] 34. A further object of the invention is to provide a method for coating a substrate with a fluid heat reactive resin system which does not materially distort or degrade the substrate.
[35] 35. And yet a further object of the invention is to provide a method for configuring a shape from a fluid heat reactive resin system and curing the shape using low temperature curing.
[36] 36. And yet a further object of the invention is reduce the cycle time of injection molding shapes from heat reactive resin systems.
[37] 37. And yet a further object of the invention is to prepare heat reactive resin system that is mobile at temperatures below the melting point of the base resin.
SUMMARY OF THE INVENTION
[38] 38. These, and other objects of this invention are achieved by solvating a resin in a liquified gas in the supercritical range, mixing a curing agent and other desired additives with the solvated resin in a pressure vessel, depressurizing the vessel slowly to avoid significant foaming, and discharging a fluid heat reactive resin system. The fluid heat reactive resin system may be configured into a shape or applied as a coating to a substrate by spreading, for example, and cured at a low temperature. Alternatively, the fluid heat reactive resin system may be spread in a thin sheet to allow the residual liquified gas and solvent/plasticizer to escape more rapidly and subsequently pulverize the non-solvated, now solid, heat reactive resin system, for application by conventional powder coating methods; or, it can be agitated during solidification to form a powder directly.
[39] 39. The preferred liquified gas is carbon dioxide but other gases such as sulfur dioxide, low boiling hydrocarbons and their derivatives and the like can prove useful. After the dispersion has been completed, agitation has ceased and the solvated heat reactive system has separated from the liquid phase, the liquified gas is slowly depressurized from the top of the vessel in a manner that avoids or minimizes the formation of foam. Surprisingly, the heat reactive resin system can be maintained in a fluid state for a significant period of time after liquified gas has been relieved from the vessel which permits discharging the resin system from the pressure vessel and manipulating it as by pumping, shaping, dispersing, spraying, calendaring, dip coating, extruding, etc. after discharge. The elapsed time that the heat reactive resin system remains fluid and is capable of manipulation is here referred to as the “transient processing time”—which can vary from several minutes to several hours depending on the temperature of the system, the surface to volume ratio into which the resin system is configured and the amount of high boiling solvents or plasticizers included in the system.
DETAILED DESCRIPTION OF THE INVENTION
[40] 40. A standard pressurized reactor equipped with means for heating, cooling and mixing is suitable for carrying out the process of this invention. The ingredients required to form a heat reactive resin system are charged to the vessel. Suitable ingredients include the base resin, curing agents, accelerators and other additives such as pigments to provide the desired end use properties. Preferred resins that are commonly included in the formulation of coating powders are described, for example, in the Kirk-Othmer reference, supra, in Powder Coatings Chemistry and Technology by T. A. Misev, J. Wiley & Sons (1991), chapters 2-4 and in the Science of Powder Coatings—Chemistry, Formulation and Application , Volume 1, by D. A. Bate, published by SITA Technology (1990) Chapter II and III. In general, these resins have molecular weights (M n ) in a range of about 500-100,000 but mostly in a range of about 1,200-10,000. To maintain flowability in storage, the preferred Tg of the resins is usually greater than about 40°C. and preferably above about 50°. Resins useful in the practice of this invention are most commonly epoxy resins, polyester resins, both hydroxyl and acid functional, amorphous and semi-crystalline types as described in PCT WO 91/14745, acrylic resins both hydroxyl and acid functional, and combinations thereof. Thermoplastic and thermosetting resins can be used in combination. In the case of thermosetting resins, suitable curing agents include dicyanamides and derivatives, amines, imidizoles, phenolic resins, carboxyl functional polyester or acrylic resins for the epoxy resins, blocked isocyanate, uretdione and amino resins for hydroxyl functional polyester or acrylic resins, dibasic aliphatic acids or polymeric polyanhydrides for glycidyl functional acrylic resins and triglycidyl isocyanurate (TGIC) and other glycidyl functional resins and compounds and hydroxyalkyl amide curatives for acid functional polyester and acrylic resins.
[41] 41. Additives are often included in the heat reactive resin systems for special purposes. These may include flow control additives, degassing additives, surface active agents, charge control additives (especially in the case of electrostatic toners) mar and slip additives, heat and light stabilizers, waxes, gloss control additives and many others. Pigments and inert extenders such as barium sulfate or calcium carbonate are sometimes useful.
[42] 42. It has been found that the transient processing time can be materially extended if minor amounts, e.g. 10% or less by weight, of high boiling solvents or plasticizers are included in the heat reactive resin system.
[43] 43. After all the ingredients have been charged to the reactor, it is sealed and the liquefied gas introduced. Agitation can be started as soon as the resin mixture is wet out by the liquefied gas or delayed until the vessel is filled with the liquefied gas and adjusted to the desired conditions of temperature and pressure. The ratio of liquefied gas to the resin mixture can vary over a wide range. As low as 10% (all percentage are given in the specification and clams by weight unless otherwise noted) resin mixture and 90% liquefied gas to as high as 80% resin mixture and 20% liquefied gas are useful in the practice of the invention. Quite generally, a ratio of about 20-60% resin mixture to gas is a convenient ratio.
[44] 44. If the gas is CO 2 , a range in temperature from ambient temperature to about 160°C. is useful but a range of from about 30°C. to 150°C. and more preferably a range of about 30°C. to about 90°C. is preferred. With regard to pressure, it must be high enough to maintain the gas in a liquefied state. Pressures of from about 300 psi to about 20,000 psi may be utilized. When the gas is CO 2 pressures of about 800 psi to about 6,500 psi are useful and more preferably are in a range of from about 1000 psi to 5000 psi.
[45] 45. The resin mixture is mixed with the liquefied or supercritical carbon dioxide until the resin is solvated. This occurs in a relatively short period of time, or about 5-30 minutes, after the desired conditions of temperature and pressure are attained. The ingredients in the resin mixture can be dispersed by continuing to mix them in the pressurized vessel. Alternately, the dispersion can be carried out after the vessel has been essentially depressurized by removing the liquefied carbon dioxide and causing the liquefied solvated resin mixture to flow through a media mill, roll mill, colloid mill or other suitable dispersion device while at atmospheric pressure. Sufficient gas pressure can be retained in the reactor to force the heat reactive resin through the dispersion device or a pump can be used.
[46] 46. In one embodiment of this invention, two pressure vessels are used in tandem in a semicontinuous process. After the resin mixture is mixed with the supercritical CO 2 and a heat reactive resin system is established, the liquefied CO 2 is allowed to separate from the heat reactive resin system by stopping the agitation. The supernatant CO 2 is transferred to a second pressure vessel into which the ingredients of a resin mixture have already been added thereby leaving the solvated fluid heat reactive resin system in the first vessel at atmospheric pressure or at a pressure sufficiently low to aid in removal of the fluid heat reactive resin system from the vessel. While the fluid heat reactive resin system is discharging from the first vessel, a solvated resin mixture is formed in the second vessel. When the first vessel is fully discharged, it is charged with a new resin mixture, sealed and filled with some of the CO 2 from the second reactor. The second reactor is then discharged. This procedure is sequentially repeated to reduce consumption of CO 2 and to yield a relatively continuous stream of fluid heat reactive resin systems.
[47] 47. The following example is given to illustrate the practice of this invention. However, it should not be construed as limiting since many variations of the procedure will be apparent to those skilled in the art.
EXAMPLE
[48] 48. The following materials were charged to a 1 liter pressurized stirred reactor equipped with a turbine agitator (Pressure Products—LC Series)
Epoxy Powder (1) 250 g Aluminum Paste (2) 13.5 g
[49] 49. (1) The composition of the epoxy powder is as follows:
Epoxy resin (a) 48.0 DEH 85 (b) 15.4 B-68 (c) 0.9 Resiflow P-67 (d) 0.7 TiO 2 24.0 Calcium Carbonate 11.0
[50] 50. (2) Aluminum paste, SBC-516-20Z from Silberline manufacturing 55.4 wt % aluminum flake, 44.6 wt % mineral spirits. In this Example the mineral spirits were present in the heat reactive resin system in an amount equal to 2.3 wt % (13.5×0.446/263.5) This presence of mineral spirits is most important. It is believed that the mineral spirits act as a plasticizer or a high boiling solvent for the resin and is responsible for establishing and extending the transient processing time.
[51] 51. Components 1 and 2 were dry mixed and added to the reactor which was then sealed. An agitator in the reactor was started at 400 rpm and liquefied carbon dioxide was allowed to flow from a pressurized cylinder into the reactor while the reactor was being heated. After 5 minutes, the vessel was full of carbon dioxide and the pressure gauge registered 800 psi. While carbon dioxide continued to flow from the cylinder, the pressure relief valve of the reactor was opened slightly to allow a flow rate of 5 liters per minute. After seven minutes, the temperature had reached 64°C. and the agitator started to show difficulty stirring as judged by the generation of noise. The protective shield which covers the agitator motor, agitator drive, and agitator pulley was removed and it was noted the agitator drive belt showed signs of instability, i.e., vibration. After 12 minutes, the agitator drive belt showed further signs of instability and the speed was increased to 600 rpm. It is believed that the instability of the agitator is due to the viscous nature of the solvated resin mixture. At this time, the temperature registered 64°C. After a further 5 minutes, 17 minutes total, the temperature remained constant at 64°C., the pressure at 800 psi, flow rate 5 liters per minute, and the agitation stable at 600 rpm. After 20 minutes, the temperature had increased to 69°C., the agitator speed read 567 rpm, the pressure and flow rate remained constant. After 30 minutes, the temperature read 71°C. and the agitator speed 580 rpm. After 33 minutes, the flow of carbon dioxide was stopped and the vessel allowed to depressurize at the rate of 5 liters per minute. After 40 minutes, the pressure had decreased to 400 psi and the agitator speed to 500 rpm (with no changes to the speed regulator). After 45 minutes, the pressure gauge read <100 psi and the agitator registered 284 rpm with an increasing level of instability. After 48 minutes, the vessel was completely depressurized. The temperature was 73°C. The vessel was opened in five minutes. The now visible contents had the appearance of an unfoamed resin solution. The unfoamed fluid heat reactive resin system was scraped from the agitator blades and scooped out of the pressure vessel. After about five minutes after discharge from the vessel, the fluid heat reactive resin system started to solidify, although it was still tractable. Ten minutes after depressurization, the resin system was still fluid, but had the consistency of putty and flowed only under force. After about 30 minutes, the resin system was essentially solid especially in thinner sections, i.e., less than about 5 mm. Thick sections were still slightly soft.
[52] 52. There is no disclosure in the prior art which suggests that a fluid heat reactive resin system prepared as above described can be configured as into a shape or applied as a coating to a substrate at atmospheric pressures. In this later regard, the coating can be applied to the substrate as by brushing, dipping, flow coating, calendaring, spraying or the like. The coating can then be cured by low temperature curing. If reactive, low temperature curing agents are used to prepare the heat reactive resin system, it enables the application of a coating to heat sensitive substrates, such as plastics, paper or wood, without thermally degrading or deforming the substrate. Regardless of whether low temperature acting or more conventional curative are used in the preparation of the resin system, the system can be readily converted to a powder suitable for application by conventional powder coating application methods.
[53] 53. The fluid heat reactive resin system can also be molded into a desired shape as in injection or rotational molding. | 4y
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This is a continuation-in-part of application Ser. No. 08/025,145, filed Mar. 2, 1993 now U.S. Pat. No. 5,505,805.
FIELD OF THE INVENTION
The present invention relates to a reflector and to a method of producing a reflector or mirror.
DESCRIPTION OF THE PRIOR ART
Many optical materials are used for the orderly transmission of rays by refraction or reflection, and both properties can be employed simultaneously. Materials that function by refraction are mainly characterized by the wavelength-dependence of their refractive index and of their transmittance.
In the case of mirrors and reflectors, the feature of interest is the reflectance as a function of wavelength. A metal layer of adequate thickness will absorb the rays that are not reflected. With dielectric mirrors, which can be made nearly absorption-free, a crucial factor is their ability to resist atmospheric influences and the degree to which it can be increased by protective coatings.
Whereas a large number of highly transparent glasses are available for the visible region of the spectrum, this is not the case in the UV and IR regions. Here the glasses are supplemented by a small number of crystals and materials derived therefrom, the most important property of which is high transmittance. Some of these materials (e.g. BaF 2 , CaF 2 , LiF, Al 2 O 3 , SiO 2 ) are suitable for broad-band and multispectral systems, because they are transparent from the UV to the IR. A disadvantage of some of these materials is their high solubility in water, so that rotective coatings must be applied and/or the mirrors can be used only in completely dried air.
Monocrystals (isotropic or anisotropic, depending on the kind of crystal) are obtained from natural deposits or cultured artificially (pulled from a molten mass). Polycrystalline material (isotropic) is produced by pressure sintering.
For most applications only isotropic materials are appropriate. Anisotropic crystals are used in polarization optics.
The semiconductor silicon, which is isotropic, acts as a long-pass filter with sharp cutoff, thus separating the visible from the near IR range. Polycrystalline silicon as normally employed, with a thickness of 2 mm (not treated to reduce reflection), has a transmittance τ of ca. 0.53. As wavelength increases, transmittance goes through a minimum at about 16 μm and then increases again, until it reaches 0.4-0.5 in the range above 300 μm. It is this property, in combination with its favorable thermal characteristics, that enables silicon to be used primarily in infrared optics and as a mirror substrate despite its brittleness. (Source 1: Naumann/Schroder: Bauelemente der Optik, 5th edition, p. 64, Hanser Verlag)
Surface mirrors offer many advantages over refractive systems, due to their achromatic imaging and the avoidance of other errors associated with passage through refractive materials. However, because the change in the deflection angle of a ray is twice as large as the change in angle of incidence, for given optical requirements mirror surfaces must meet stricter criteria than refractive interfaces with respect to accuracy of shape and microstructure. Another characteristic of a mirror is the shape of its spectral reflectivity curve. Although it is possible to polish the surface of a massive metal body so well that it can be used as a mirror directly, this method is used today only in exceptional cases. In general a mirror layer is applied to a mirror substrate. The metallic mirror substrate is previously polished and is responsible for the accuracy of the mirror's surface configuration. The mirror layer is applied to the substrate usually by sputtering in high vacuum or by chemical methods. The mirror layer then matches exactly the shape of the substrate surface and determines the spectral reflectance function and (in some cases together with protective layers) the temporal stability of the reflectance function. The preferred materials for mirror layers are metals such as aluminum, chromium, nickel, mercury, silver, gold, platinum and rhodium, but silicon monoxide (SiO) and silicon dioxide (SiO 2 ) are also used (Source 1).
The materials used for mirror substrates and reflectors must have a high degree of mechanical and thermal stability. Large mirrors become deformed due to their own weight when their position changes; displacements by fractions of λ must be prevented or compensated by opposing forces. Temperature changes and nonuniform temperature distributions induce internal tensions and deformations. Hence crucial requirements for a substrate material for precision mirrors are a high modulus of elasticity E and a very low coefficient of thermal expansion α. Furthermore, the material must be polishable to an optimally smooth surface with a very low proportion of scattered light.
In this respect most metal surfaces are unfavorable, because their internal texture is such that inhomogeneous properties at the grain boundaries can produce surface inhomogeneities after polishing. Nevertheless several metals are used as mirrors, including pure copper, aluminum and molybdenum alloys and pressure-sintered beryllium, though it is necessary to improve their polishability with a layer of chemically deposited nickel phosphide. Metallic mirrors have high thermal expansion, but because of their favorable thermal conductivity they do find limited application, e.g. for high-performance lasers. At present glass and vitreous ceramics are of greater significance.
Certain structural components, especially for aerospace applications, are also required to have high mechanical and thermal stability combined with a low relative weight. Furthermore, good resistance to thermal shock (RTS) must be accompanied by a low thermal expansion coefficient (TEC).
For example, future satellites are to be equipped with a mirror structure that rotates when in use. These mirrors will be large, for instance measuring 800×600 mm, and on the front side must have an optically reflecting surface.
Apparatus used in outer space can be expected to encounter cyclic temperature changes from 0 to 700 K., so that in addition to rigidity appropriate to their size they must be guaranteed to have thermal and thermal-shock resistance, a low weight per unit volume and, not least, low thermal expansion. The groups of materials that meet these criteria must also have surface properties of the high quality required for reflecting optics.
Conventional mirror components at present are made of vitreous ceramic. The manufacturing process involves the melting of various oxide powders, such as LiO 2 , Al 2 O 3 , MgO, ZnO and P 2 O 5 , in platinum furnaces. After the melt has been homogenized, objects of the desired shapes are produced by pressing, casting and other glass-forming processes. The glass components are then suddenly cooled and removed from the molds, and subsequently tempered in a controlled manner to temperatures of ca. 700° C.; in this process crystal "seeds" form in noncrystalline (amorphous) glass. If the specified temperature is maintained for a suitable time, this seed formation leads to crystal growth and completes the "ceramization" of the glass, producing a vitreous ceramic.
This crystalline vitreous ceramic possesses the advantage of low thermal expansion, only 0±0.15×10 -6 K -1 over the temperature range from 273 K. to 323 K.
As a material for mirrors, however, this vitreous ceramic is of limited use, because it can be produced only by elaborate shaping procedures and furthermore has a relatively high weight per unit volume, 2.53 g/cm 3 , as well as low tensile strength and not least a brittle breaking characteristic. In addition, it can be employed for optical components only at a constant or maximal temperature of 423 K, because the crystalline structure of such vitreous ceramics is subject to tension hysteresis in the temperature ranges 200-300 K and 360-480 K. At temperatures above 700 K the internal structure of the material is irreversibly damaged (Source 2: SiRA; ESTEC-Contract No. 5976/84/NL/PR; October 1985).
Attempts have also been made to manufacture lightweight mirror components from economically favorable aluminum (relative weight 2.71 g/cm 3 ). However, because of the low stiffness of aluminum it has been impossible so far to construct precision optics of this material. For use in corrosive surroundings, aluminum mirrors must be provided with a thick (0.2-0.5 mm) coating of nickel. Because of the massive differences in thermal expansion between aluminum (23×10 -6 K -1 ) and nickel (13×10 -6 K -1 ), these mirrors must not be exposed to any temperature fluctuations, which would cause thermally induced fracture.
Mirrors of pure aluminum, such as can be employed in a vacuum, exhibit local deformation under even slight thermal stress, due to the extremely high thermal expansion coefficients on the optical mirror surfaces. When they are used, e.g., as laser mirrors for distance measurement, such deformation can led to undefined results (Source 2).
Reflecting optics based on quartz glass are also state of the art. Because of their extremely low thermal expansion coefficients, nearly zero in the temperature range from 0 to 273 K., quartz-glass systems are eminently suitable for so-called cryogenic applications. In the range between 273 K. and 373 K. their thermal expansion coefficient rises to 5.1×10 -7 K -1 . Other disadvantages are the relatively high weight per unit volume, 2.2 g/cm 3 , the low rigidity, the low tensile strength of <50 MPa, high production costs and the restriction of the diameter to ca. 500 mm because of the complicated manufacturing process (Source: W. Englisch, R. Takke, SPIE, Vol. 1113, Reflective Optics II, 1989, pages 190-194).
Its mechanical and thermal characteristics and its low relative volume, only 1.85 g/cm 3 , make beryllium especially suitable for the manufacture of lightweight mirror structures. For example, beryllium is five times more rigid than aluminum or glass materials. Coated beryllium plates can be polished to a surface roughness (R a ) of less than 15 Angstrom, so that they are very well suited for optically reflecting surfaces.
A particular disadvantage of beryllium structures, in addition to the high cost of the raw material and of the manufacturing process, is their general toxicity. To use them as optical components under atmospheric conditions, they must first be coated with nickel. Because of the different thermal expansion coefficients of beryllium (11.2×10 -6 K -1 ) and nickel (15×10 -6 K -1 ), it is essential for these components to avoid thermal shock. Therefore they can be employed only at constant temperatures or in very narrow temperature ranges.
It has also been discovered that beryllium components manufactured by the vacuum hot-pressing technique or by high-temperature isostatic pressing have an anisotropic character, such that they have different properties in different crystal directions.
Under outer-space conditions, uncoated mirrors can be used. However, because of the high thermal expansion coefficient the temperature fluctuations typically encountered there, between 0 and 700 K., produce local deformations of the optical surface that make beryllium unusable for precision optics (Source 1) and can also introduce serious transmission problems in the case of satellite mirrors.
Mirror structures of this kind are currently also constructed of monolithic ceramic based on silicon carbide, by the so-called slip casting technique. In this casting process, a suspension of silicon-carbide powder is placed in a plaster mold shaped as a negative. Depending on the time the suspension spends in the plaster mold, a ceramic body with variable wall thickness forms; this is the positive component in the green state. After the blanks have dried, a sintering process is carried out in vacuum or protective-atmosphere furnaces at temperatures as high as 2200° C. This manufacturing technology not only requires the construction of elaborate molds to produce the green compacts, it also has the disadvantage that only certain geometries and small sizes are achievable, and the entire process suffers from a high percentage of rejects. Because these formed silicon carbide bodies shrink during drying and sintering, the required accuracy of their dimensions can be ensured only by expensive machining with diamond tools. Furthermore, the heterogeneous texture of the sintered compact makes it necessary for the compact to be coated subsequently with silicon carbide by chemical vapor deposition, to reduce the surface roughness to less than 40 Ångstrom. Not only does silicon carbide require these elaborate manufacturing and machining processes, it also has a relatively high weight of 3.2 g/cm 3 and is extremely brittle.
From DE 32 46 755 A1 it is known that highly stable, lightweight composite materials can be constructed of various laminate layers combined with cellular or honeycomb layers. Among the raw materials used are fibrous mats soaked with artificial resin, webs of paper, plastic, foil or glass, carbon-fiber mats or polyimide. The cellular or honeycomb layer is intended to endow the formed object with better stability and increased resistance to bending.
Such bonded materials based on carbon- or glass-fiber reinforced plastics are restricted to room-temperature applications. The inhomogeneous structure of the fibrous or laminated components makes it impossible for an optical mirror surface to be created by superficial processing.
From DE 38 09 921 A1 it is known that a mirror can be produced by fastening a commercially available silicon wafer to a plate substrate. To manufacture larger mirrors, several such wafers are arranged next to one another. At the joints between them, the wafers are connected to one another by laser or electron-beam welding. The mirror surface is subsequently ground and polished. A body of lightweight metal or fiber-reinforced composite plastic is used as the substrate. Here, again, the above-mentioned disadvantages appear, caused especially by the use of different materials for substrate and reflector layer.
From DE 36 26 780 A1 it is known that mirrors can be used not only to reflect light but also as antennae. The mirrors disclosed there comprise a carrier made of carbon-fiber reinforced material. The reflector layer consists of glass or vitreous ceramic and is melted directly onto the substrate. The disadvantages of such mirrors have been described above.
From DE 30 18 785 A1 a method of producing mirrors is known in which the first step is to produce a preform made of a highly thermally stable material, namely carbon, which serves as substrate structure for the mirror. To form the mirror, a front plate of glass is sintered or melted onto this substrate structure. The result, again, is a structure in which the substrate plate and the reflector layer have very different thermal properties, so that such mirrors are only very slightly resistant to thermal shock. The weight per unit volume of such mirrors is relatively high.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a reflector and a method of producing same whereby the reflector has improved mechanical/thermal properties with simultaneously improved optical properties with respect to the prior art and is also simple to manufacture.
According to a first aspect of the present invention there is provided a reflector for the reflection of electromagnetic radiation comprising a substrate element of porous and at least partly carbidized carbon, a first coating of at least one of silicon and silicon carbide attached to the substrate element with its surface facing away from the substrate element having been smoothed and subsequently provided with a reflecting layer of at least one of silicon, silicon carbide, silicon oxide, silicon nitride, gold, silver, nickel, copper, and alloys of the afore-mentioned metals.
According to a second aspect of the present invention there is provided a method of producing a reflector for the reflection of electromagnetic radiation, comprising the steps of:
a. producing a porous substrate element from one of carbon and a carbon-containing material that has been carbonized or graphitized;
b. coating the substrate element with a first silicon coating in the form of one of powder, silicon preforms, and silicon disks;
c. infiltrating the substrate element with silicon at a temperature in the range 1300° C. to 1600° C. in an oxidation-preventing atmosphere or in vacuum, so that the porous substrate element is impregnated with liquid silicon and, at the interfaces between the porous material of the substrate and the liquid silicon, a silicon carbide layer is formed, and so that the first silicon coating is joined to the infiltrated substrate element by melting-on or sintering in a high-temperature treatment;
d. cooling the substrate element with its first silicon coating thereon; and
e. applying a reflecting layer of at least one of silicon, silicon carbide, silicon oxide, silicon nitride, gold, silver, nickel, copper, and alloys of the aforementioned metals.
It is an important feature of the invention that the substrate element is initially made of an easily processed material, namely substantially carbon, which is not endowed with its special characteristics until it is impregnated with silicon, after which it can be processed only with greater effort. An additional feature is the fact that the actual reflecting layer is applied to a silicon layer that is deposited on the (silicon-impregnated) substrate element and firmly joined to the latter. It is also possible, instead of depositing the silicon layer separately, to impregnate the substrate element with molten silicon in such a way that its outer surfaces substantially comprise a silicon layer free of openings or pores. This can then be smoothed and coated with the actual reflecting layer.
In the following description, the use of carbon or carbon fibers is described as the basic material for construction of the preforms. At this juncture, however, it should be stated expressly that the development of materials with similar fine-structural characteristics or the use of such substances is included within the ambit of this invention. Any suitable material that can be "impregnated" in order to permit firm fixation of the silicon reflector layer onto the core structure can be used.
Furthermore, it should be pointed out that the following description refers in general to the use of preforms or wafers made of silicon for construction of the outer layer. It is also possible to use metallic silicon in granular or powder form, in which case subsequent mechanical processing such as grinding and/or polishing will be required.
CFC composites comprising a carbon matrix with carbon-fiber reinforcement are produced industrially by the resin-impregnation and carbonization method. The resulting materials are distinguished by an extraordinarily favorable combination of characteristics, such as high mechanical stability in space and at high temperatures, combined with low weight per unit volume (1.0-1.7 g/cm 3 ) and low brittleness.
Set against the excellent material characteristics of CFC is its low resistance to oxidation, which greatly limits the possibilities for employing the material in an oxygen-containing atmosphere. At present its low resistance to oxidation restricts CFC to use in vacuum and protective atmospheres, because otherwise at temperatures above 400° C. it begins to burn away.
To increase the oxidation resistance of this material, the so-called ceramic matrix composites (CMC) were developed. Here refractory and ceramic components are infiltrated into the porous CFC matrix. It is also possible to manufacture short-fiber preforms, in which short carbon-based fibers are dissolved in a phenolic-resin suspension and harden when the temperature is increased. When the temperature is further increased in the absence of oxygen, the resin binders of the two composite qualities are carbonized.
The reflector in accordance with the present invention has as its basic structural element fiber-reinforced CFC or CMC or carbon-honeycomb composites plus superficial metallic silicon. Here metallic silicon is understood to mean elementary silicon that as been applied to CFC carrier substrates as silicon preforms or wafers or silicon powder, by processes of diffusion, sintering or melting-on. Silicon wafers are thin metallic pieces comprising highest-purity silicon. The silicon can have an isotropic or polycrystalline structure.
On the whole, carbon-fiber reinforced carbon bodies differ from other known carbon materials in that they have a number of improved mechanical and physical properties and can be employed at temperatures up to 2200° C. in an inert atmosphere. These characteristics can be varied over wide ranges because of the many ways to modify the manufacturing process, i.e. by altering the type of carbon fiber and fiber pretreatment, the fiber orientation or arrangement, the fiber content, the forming method (pressing, lamination or rolling), the number of subsequent densification cycles and in some cases the annealing and graphitization temperatures. By these means the constitution of the material, in particular the structure, the matrix and the porosity, can be influenced in specific ways and matched to the requirements of the intended application.
In principle it is likewise possible to use silicon carbide reinforced with silicon carbide fibers rather than carbon fibers in the present invention.
It is also in accordance with the invention to use a vapor-silication process. Here the porous substrate elements are infiltrated by exposing them to a silicon-containing atmosphere (silicon vapor) at temperatures between 1600° C. and 2300° C.
The invention enables the manufacture of components with complex geometry, high temperature-shock resistance, low relative weight (0.5-2 g/cm 3 ) and simultaneously high tensile strength (>150 MPa), low thermal expansion coefficient (TEC) and surfaces suitable for reflecting optics.
Another advantage of the method in accordance with the invention is that economically priced, commercially available materials can be used, which can be processed with machine tools before they are "treated" with silicon.
Furthermore, the density and strength of the component can be adjusted as desired, by suitable choice of substrate structures and of the quantity or quality of the infiltration processes. The thermal expansion coefficients of the groups of materials used in accordance with the invention closely resemble one another, resulting in very precise elements of stable form even when the dimensions are large.
Any CFC raw materials can be used advantageously, in particular those based on long or short fibers and with oriented or unoriented fiber structure. Moreover, the method in accordance with the invention can also be applied to known honeycomb structures based on paper, cellulose or carbon fiber.
The density of a CFC block is at most 1.4 g/cm 3 ; that is, it has high porosity. Apart from the pores, the block contains no cavities, so that with respect to its shape it is a massive body such as a plate, a brick or a solid cylinder. For multidimensionally oriented CFC qualities with long-fiber construction, as a rule, one begins with resin-impregnated carbon-fiber webs, so-called prepregs, which are compressed into CFC plates in heatable axial presses
To produce CFC blocks on a short-fiber basis, carbon or graphite fibers are suspended in a thermosetting resin binder, as known in the art. The suspension is poured into a mold and then the solvent is removed, e.g. by heating, and the resin binder and hence the CFC block is hardened. In all CFC qualities the fiber reinforcement is intended to counteract embrittlement of the ceramized CFC material and maintain quasiductile fracture behavior. The honeycomb structures manufactured by the known molding methods, from hard paper or carbon fibers, are treated to increase the carbon yield by impregnation with a resin binder, preferably phenolic resin, and hardened by subsequent heat treatment.
The next step is common to all CFC or honeycomb structures: carbonization of the binder resin in vacuum or protective atmosphere at temperatures of, e.g., 900°-1300° C. The CFC blocks or honeycomb structures so obtained are then preferably heated in vacuum or protective atmosphere to temperatures of more than 2000° C., to achieve at least a partial graphitizing of the carbon matrix and fibers.
The block is then machined down to produce the CFC blank, which has the dimensions of the component to be manufactured, such as the basic mirror structure of a satellite or other optically reflecting system. The removal of material in this process can be done, for example, by turning, milling or grinding, with the same machines as are ordinarily used for the machining of metallic materials. To achieve further weight savings, during the machining of the CFC blanks pockets of any desired geometry can advantageously be milled, eroded or drilled into the back surface of the mirror structures. After carbonization the carbon honeycomb structures can be laminated to form a composite by attaching to the front surface carbon-fiber webs of any kind or web prepregs, by means of a resin binder. Furthermore, it is possible to press the honeycomb structures into the highly porous short-fiber CFC or to construct a sandwich system by pressing together several honeycomb structures, each encased in a CFC web. In this way, after carbonization a highly thermostable, lightweight construction material is obtained, with great rigidity and quasiductile fracture behavior.
The CFC or honeycomb blank obtained after machining, which like the block has a low density of 0.1-1.3 g/cm 3 and hence a high porosity, up to 90 vol. %, can subsequently be further infiltrated and stabilized by impregnating it with resin binders and carbonizing them.
Another way to achieve the necessary strengthening of the CFC blanks and thereby increase the rigidity of the basic mirror structure is by infiltration with pyrolyric carbon by chemical vapor deposition (CVD), until the density reaches a maximum of 1.4 g/cm 3 but preferably 0.3-1.0 g/cm 3 . Whereas in resin impregnation phenolic resins are preferred, in the chemical vapor deposition of carbon it is preferable to use a mixture of hydrocarbons, such as methane or propane, and an inert gas, such as argon or nitrogen, at a temperature between 700° and 1100° C. and a pressure of 1-100 millibar. The gas mixture diffuses into the porous structure and breaks down to form carbon and hydrogen, the carbon preferably being deposited as pyrolyric carbon on the surfaces or at the intersection points of the fibers and thereby strengthening the structure.
The CFC blanks obtained from either infiltration process are polished on the surfaces intended for reflection and fitted into a vacuum or protective-atmosphere furnace. One or several metallic silicon preforms are laid onto the polished side and the sample is heated to temperatures of 1300°-1600° C., preferably 1350°-1450° C. As the result of a chemical reaction between the carbon and the silicon, silicon carbide forms at the interfaces, creating a consolidation or joint and thereby attaching the silicon wafer to the the CFC substrate. In addition to the chemical reaction, melting-on of the metallic silicon and diffusion can also cause the wafer to become attached to the CFC blank, forming optically reflecting structures.
Metallic silicon wafers can be fixed to so-called ceramic-matrix composites (CMC), which for example contain silicon carbide and silicon in the matrix, at temperatures of 1300°-1600° C.
An especially advantageous version of the method in accordance with the invention also provides for the surfaces that are to be made reflective to be covered with one or more silicon preforms or silicon wafers and for the substrate thus prepared to be positioned with its lower end in a pool of molten doped silicon. Due to the capillary forces in the substrate structure, the molten silicon ascends in the blank until it reaches the high-purity silicon preforms or powder resting on its upper surface. Firstly, the blank is thereby upgraded to a CMC and the silicon preforms or wafers or the powder mass resting on it are joined to one another and fixed to the substrate. In addition, substrate structures comprising several discrete elements assembled by mechanical means can be consolidated into a single unit by the ascending silicon.
The amount of molten metallic silicon used to infiltrate the CFC blank should be such that the density of the latter is less than 2.0 g/cm 3 , preferably 1.5-1.8 g/cm 3 . It is advantageous for the commercially available metallic silicon-monocrystal wafers to have been pre-ground and polished in such a way that after application to the substrate they immediately form optically reflecting surfaces, so that machining cycles can be reduced to a minimum or eliminated altogether. To prevent massive melting-on, deformation and volatilization of the applied silicon elements, a maximal process temperature of 1550° C. must not be exceeded; the process temperature is preferably between 1350° and 1500° C. In a particularly advantageous version of the method in accordance with the invention, the silicon preforms are attached to the CFC or CMC or honeycomb substrate prior to fixation by means of an adhesive or resin binder, which during the subsequent heat treatment facilitates the processes of diffusion, sintering or melting-on at the interface between the substrate and the silicon preforms.
As adhesives or resin binders it is advantageous to use precursors based on polysilane or silicon carbonitride and/or adhesives based on silicon, silicon carbide or carbon or silicones. Before the reactive fixation process the adhesives must be dried or hardened at temperatures between 100° and 200° C. Pyrolysis of the resin binders is carried out at 1000° C. in vacuum or in a protective atmosphere.
Polysilanes (polymethylphenylsilanes), for example, after pyrolysis under inert gas at 1200° C. give a ceramic solid yield of 30% to maximally 70% by weight, depending on the solvent.
For mirror and reflector applications in the temperature range of, for example, 250 and 330 K. with no major temperature fluctuations, a sufficiently firm attachment between the substrate and the mirror layer can be achieved by attachment of the silicon parts to the substrate structures with silicones.
Glass frits can also be used, with suitable tempering above 600° C., to fix the silicon preforms to the CFC or CMC substrates by melting-on processes.
The method in accordance with the invention further provides for several silicon preforms or Si wafers or also powder differing in doping or melting points to be applied as so-called multilayers to the CFC or CMC or honeycomb substrate structures, the silicon preforms preferably being arranged in such a way that the one with the lowest melting point is placed directly on the substrate and all the silicon preforms arranged above it have a higher melting point. Undoped highest-purity silicon, for example, has a melting point at 1412° C. Depending on the amount of impurities in silicon (doping), the melting point can be lowered by various amounts due to the formation of eutectics.
It is in accordance with the invention for the reflecting layers, comprising carbon or silicon carbide or silicon or silicon dioxide or silicon nitride or gold or silver or nickel or copper or alloys thereof, to be applied to the unprocessed or ground reflector surface of the substrate made of ceramic matrix composites (CMC) by physical vapor deposition (PVD), preferably in the temperature range from 20° C. to 900° C., in vacuum or under a protective atmosphere.
In contrast to layers obtained by thermal spraying, which are applied by transferring droplets or particles to the substrate surface, these PVD coatings are produced by the deposition of atoms or molecules from the gas phase to form a layer the thickness of which can range from a few Ångstroms to several millimeters. The most widely used forms of PVD layers include vacuum metallized layers, sputter layers and ion-plating layers. By this means various materials, for example, metals, metal alloys, glasses, ceramics and non-metals as well as plastics, can be deposited on surfaces.
In vacuum metallization methods, metals or compounds are vaporized in a vacuum and deposited on mirror-substrate surfaces that are at a considerably lower temperature than the vapor. The energy with which the atoms or molecules strike the substrate surface is low and insufficient to produce good adhesion of the layer. Therefore the surface of the side of the mirror to be coated is specially prepared. This can be done, for example in the vaporization apparatus, by bombarding the surface with ions of inert gases in a glow-discharge plasma and/or by heating the parts to several 100° C. in order to volatilize impurities and adsorbed films (moisture). The coating material is vaporized thermally by resistance heating or high-frequency heating or by means of an electron or laser beam. In the vacuum method the free path length of the atoms/molecules is some meters, so that the particles can pass directly, i.e., without colliding with the molecules of the residual-gas atmosphere, to the substrate surface and condense there to form the deposited film.
Reflecting layers of the reflectors in accordance with the invention can also be produced by so-called sputter methods. Here a cloud of particles is produced in a glow-discharge plasma. By applying a voltage of ca. 1-10 kV across a noble gas (e.g. Ar) between the cathode, which consists of the coating material, and the anode, noble-gas ions (Ar + ) are produced, with which the cathode is bombarded. Atoms of cathode material thereby removed are deposited on the mirror substrate, which is positioned near the cathode. Component (sample holder) and recipient are grounded. In a modification of the method, the sputtering can also be done in a reactive-gas atmosphere, with which the metal atoms leaving the cathode react to form compounds such as carbides, nitrides or oxides, which then deposit to form a coating.
In ion plating the coating material is vaporized into a plasma, which is maintained between the vaporization source and the mirror component to be coated, and deposited from the plasma onto the substrate. In an evacuatable apparatus the coating material is vaporized by means of thermal vaporizers, induction heating or electron gun. Between the substrate, which serves as the cathode, and the anode (vaporization source) a plasma is produced. The mirror substrate is bombarded with anions produced in the plasma by impact ionization of the noble gas. As a result, layers of foreign material are removed from the substrate and its surface is cleaned, slightly etched and activated. About 1% of the particles of coating material that enter the plasma from the vaporization source are ionized by impact ionization and accelerated in the electrical field toward the mirror substrate, which if it consists of nonconducting material is covered with electrically conducting wire mesh to serve as the cathode. The accelerated ionized particles lose their charge by charge exchange, but even in this state they retain the velocity they had acquired as ions, so that they strike the substrate surface with high energy. Because the sputtering away from the surface and deposition of the coating material occur at the same time, the clean surface required for the optimal build-up of a layer is always available. Penetration of the substrate surface by the accelerated particles produces a kind of diffusion layer, which is responsible for the outstandingly firm adhesion of the ion-plated coating. In ion plating, again, the variant of reactive ion plating exists. Substances introduced into the plasma react either here or on the substrate with the partner, to form new layer-producing substances.
In vacuum metallization and in ion plating, the mirror components are exposed to temperatures up to 800° C. or more, so that there may advantageously be an influence on the substrate material (an interlocking or adhesion-mediating layer). When layers are deposited by sputtering, the mirror substrate is heated only to ca. 300°-500° C. In the case of reflector components with complex shapes, sputtering is the method of choice because of the high degree of scattering achieved. Excellent adhesion of the layer to the mirror substrate is produced by sputtering and ion-plating.
Alternatively, it is in accordance with the invention to apply to the unprocessed substrate structure, or to the ground reflector surface of the substrate structure made of ceramic matrix composites (CMC), surface-refining and/or reflecting layers consisting of carbon or silicon carbide or silicon or silicon dioxide or silicon nitride or nickel or alloys thereof by chemical vapor deposition (CVD), preferably in the temperature range from 600° C. to 2000° C., in vacuum or under a protective atmosphere.
The term chemical vapor deposition basically denotes that various reactive and carrier gases are thermally decomposed in particular stoichiometric proportions and thus react to form the deposited solids plus gaseous side products. As solid products, metals, metallic and non-metallic compounds and organic structures in the gas atmosphere surrounding the object to be coated can be formed on the surface of the object and deposited there. The substrate material can be any metal or non-metal that is not damaged by the high temperatures necessary for the chemical reaction. The CVD method permits, for example, the manufacture of ceramic layers and structures of extremely high purity, with unique mechanical, chemical, thermal, electrical and/or optical properties.
In a CVD process (superficial deposition) the flowing gas or gas mixture is thermally decomposed, in the gas phase and/or at the hot component to be coated. The non-volatile products of this decomposition, such as carbon or silicon or silicon carbide, form nuclei that grow and produce a layer on the mirror component. The most important physical process parameters for deposition in the CVD reactor are the temperature, the temperature distribution, the partial pressure, the amount and composition of the gas and the gas velocity, together with the associated flow conditions at the component and in the reactor. Aspects specific to the apparatus and component, such as the design and dimensions of the furnace, the geometry of the object being treated and its position in the furnace, also play a role, and the material of which the substrate is made is not least of the factors with a decisive influence on the operation of the process.
Another embodiment in accordance with the invention provides that the optically reflecting layer, which comprises nickel or silver or gold or copper or alloys thereof, is applied to the ground reflector surface or to the substrate structure made of CMC by electrolysis, preferably in the temperature range from 20° C. to 200° C.
Thermal spray-coating methods such as flame spraying or plasma spraying can also be employed to apply reflecting layers consisting of silicon or silicon carbide or silicon oxide or silicon nitride or nickel or alloys thereof. The reflector layer is produced by transferring to the mirror-substrate surface droplets or particles of the material to be applied.
Fixation of the silicon preforms to the substrate structures is made possible at considerably lower process temperatures (so that in the case of certain applications, it is possible to work in a normal atmosphere, without protective gas or vacuum) by coating the silicon preforms with gold before they are attached to the substrate structure. In the temperature range 350°-400° C. silicon forms a plastic deformable melt eutectic with gold. As a result, it is possible to attach the silicon preform, e.g. wafer, to the substrate structure by melting-on at temperatures of 300°-600° C.
Gold has the advantage that its thermal expansion coefficient is similar to that of silicon, so that there is no danger of thermal damage as a result of temperature fluctuations. Another advantage of gold is that, because of its chemical inertness, it reacts only with silicon. As a result, in the limiting case gold-coated silicon preforms can be melted onto the substrate structures in a normal atmosphere in the low temperature range of ca. 300°-450° C., which considerably reduces the cost in comparison to melting-on in a protective atmosphere or in vacuum. Where the contact between the silicon preform and the substrate structure must be of high quality, however, sintering in vacuum is preferable.
The silicon preforms can be coated with gold, e.g., by applying gold foil or by physical vapor deposition (sputtering), and the thickness of the coating should be approximately in the range 0.5-50 μm. In principle the gold coating can be applied to the surface of the substrate that is to be made reflective, rather than to the silicon preform.
Instead of gold it is also possible, in principle, to use other nonferrous metals or materials that form a plastic deformable melt eutectic with silicon. An example is aluminum, which forms a melt eutectic with silicon in the temperature range ca. 500°-650° C. However, because aluminum can oxidize to form an Al 2 O 3 layer which would inhibit sintering, it must be applied under vacuum or in a protective atmosphere. Furthermore, aluminum has a higher thermal expansion coefficient than silicon, which limits its use for applications involving marked temperature fluctuations.
The choice of a coating material in any individual case will depend on the conditions of use, quality considerations and the costs of materials and manufacturing processes.
The present invention will now be described by way of four specific examples of preferred embodiments, with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a polished cut section of a silicon wafer fixed to a CMC substrate at 20-fold magnification;
FIG. 2 shows the section of FIG. 1 at 40-fold magnification;
FIG. 3 shows the section of FIG. 1 at 100-fold magnification;
FIG. 4 shows the section of FIG. 1 at 200-fold magnification;
FIG. 5A is a perspective view of a large mirror composed of facets;
FIG. 5B is a perspective view to an enlarged scale of part of the mirror shown in FIG. 5A;
FIG. 5C is a view similar to that of FIG. 5B but of another embodiment of mirror;
FIG. 6A is a longitudinal section through a preferred embodiment of a substrate preform,
FIG. 6B is a section along the line VI--VI in FIG. 6A;
FIG. 7 shows a silicon wafer fixed to a honeycomb structure enclosed in carbon-fiber web;
FIGS. 8A to 8D show different aspects of a preferred embodiment of an infrared telescope mirror;
FIGS. 9A to 9C show steps in the production of another preferred embodiment; and
FIGS. 10A and 10B show steps in the production of a further embodiment similar to that shown in FIGS. 9A to 9C.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
EXAMPLE 1
40 carbon-fiber web prepregs with sateen weave, a phenolic-resin component amounting to 35% by weight and a diameter of 150 mm are compressed for 8 minutes in a heatable axial press at a temperature of 200° C., producing a CFC preform with a diameter of 150 mm and a wall thickness of 12 mm. The object produced by the forming process, for example this disk, is then carbonized in a reactor with oxygen excluded, i.e. in vacuum or a protective atmosphere, at ca. 1000° C. To minimize the reactivity of the carbon fibers and/or to influence the modulus of elasticity, the block is exposed to a temperature of more than 2000° C. in the absence of oxygen, i.e. in vacuum or a protective atmosphere, as a result of which the matrix carbon formed by carbonization of the phenolic resin is at least partially graphitized. This graphitization is produced, for example, by heating at a rate of 30 K./min and holding for 2 hours at 2100° C. The CFC block thus obtained has a density of 1.0 g/cm 3 .
The block is then machined by turning, milling or grinding to produce the blank shown in FIG. 6 which serves as the substrate for optically reflecting mirror structures.
The blank is again impregnated with phenolic resin, in a pressure autoclave at 500 bar. After the pressure impregnation, a preform made of metallic silicon (diameter 123 mm, wall thickness 0.8 mm) is glued to the component. As the glue, for example, a commercially available silicon carbide adhesive of type RTS 7700 made by the firm of Kager is used, which dries at 100° C. in air without shrinking. The impregnated component is carbonized anew in a reactor at 1000° C. and a pressure of 10 mbar. The rate of heating is 2 kelvin per minute, and the holding time is 12 hours.
The blank with attached silicon preform and a density of 1.18 g/cm 3 is now heated in a vacuum furnace at a rate of 20 K. per minute to a temperature of 1390° C. and held there for 30 minutes. After it has cooled to room temperature, the silicon disk is firmly interlocked with the CFC, without deformation.
Microscopic examination of the surface of a section through a reference component confirmed that the silicon preform was joined to the CFC substrate by firm interlocking with no discernible fissures and pores. Polishing trials employing submicron diamond suspensions showed that the silicon surface can be polished with no difficulty so as to reduce the surface roughness R a to less than 15 Ångstrom, so that it is eminently suitable for optically reflecting structures. Finally, gold is applied to the mirror surface by PVD.
EXAMPLE 2
Short carbon fibers, 10-30 mm in length, are reduced to a slurry in a phenolic-resin suspension. The fiber content of the suspension is 40% by weight. The suspension is poured into a cylindrical mold with a diameter of 150 mm and a height of 100 mm. The solvents contained in the phenolic resin are removed at 60°-70° C. in vacuum. When the temperature is raised to 180° C., the phenolic resin hardens. After removal from the mold, the cylindrical CFC block is carbonized in the absence of oxygen, as in Example 1.
The CFC block so obtained, with a quasi-isotropic internal structure, has a density of 0.55 g/cm 3 and a porosity of about 70 vol. %. To minimize the reactivity of the carbon fibers and/or to convert the matrix carbon formed from the phenolic resin at least partially to graphite, graphitization is carried out at temperatures of more than 2000° C., as described in Example 1.
From the cylindrical block the components illustrated in FIG. 6, which can serve as substrates for the satellite mirror structures, are produced by machining in a lathe, milling machine and/or polisher.
The components are infiltrated with pyrolytic carbon by chemical vapor deposition. This process is carried out in a vacuum furnace for 50 hours at 750° C., with a partial pressure of 2 mbar, the gas phase comprising propane and argon in the ratio 1:5. When it has been completed, the density of the components is 0.90 g/cm 3 and their open porosity has been reduced to ca.
Now the components are placed in a high-temperature vacuum chamber in a graphite vessel, the floor of which is covered with molten metallic silicon. The molten silicon rises within the blank by capillary action, filling its pores almost entirely with silicon. When the temperature is raised further, to about 1750°-1800° C., some of the metallic silicon is converted to silicon carbide by combination with pyrolytic carbon.
After cooling to room temperature, the component has a density of 1.75 g/cm 3 , 20% of the matrix being composed of unreacted, free metallic silicon.
The resulting ceramic-matrix-composite (CMC) component 10, with recesses 16 and drilled holes 17, is now polished with a polishing machine on its front side, the side intended for the mirror surface. A silicon preform 11 with a diameter of 123 mm and a wall thickness of 1.0 mm is laid onto the polished surface, with no application of adhesives or resin binders, and the structure is fitted into a protective-atmosphere furnace. In an argon atmosphere the component is heated to 1405° C. at a rate of 30 K./min. After a holding time of 20 minutes the structures are cooled to room temperature.
A reflecting layer is applied.
To check the fixation or joining of the silicon parts, a component was sawn apart and the cut surfaces polished. That the silicon had been sinter-fused without fissures, pores or other gaps is illustrated by the photomicrographs in FIGS. 1 to 4. The interlocking has evidently been brought about by processes of diffusion and sintering between the silicon in the CMC substrate and the silicon preform.
After processing, the mirror structures are examined with respect to their resistance to thermal shock. In a hundred trials the structures were exposed to cyclic temperature fluctuations in the range 0-700 K., after which they were polished to reveal the internal structure. No fissures had formed in substrate or silicon, or at the interface between them.
A rod with the dimensions 50×4×4 mm was sawn out of the superficial part of a mirror structure and subjected to dilatometer measurement. In the temperature range 0-700 K. the mirror material exhibited a thermal expansion coefficient of only 2.0×10 -6 K -1 .
EXAMPLE 3
A CFC block is produced according to Example 1. After carbonization, graphitization and infiltration by chemical vapor deposition, the CFC cylinder is machined to the configuration shown in FIG. 6. A silicon wafer with a wall thickness of 0.8 mm is glued to the highly porous CFC component by means of polysilane precursors supplied by the firm of Wacker. After the resin has dried and hardened in an argon atmosphere at 180° C., the component is heated further at a rate of 3 kelvin per minute until it reaches 1200° C., so that the polysilane precursors are pyrolyzed.
The CFC structure is then put into a vacuum furnace, within a graphite crucible filled with pulverized metallic silicon. At a heating rate of 20 K. per minute the system is brought to 1400° C., and after 30 minutes at that temperature it is cooled to room temperature. Due to doping, the silicon melts at only about 1350° C. and diffuses into the porous CFC matrix as far as the substrate-wafer interface, bringing about a so-called reactive fixation of the silicon wafer to the composite. Inspection of the structure in a polished section shows that some of the infiltrated silicon has combined with pyrolytic carbon to form silicon carbide and that the content of unbound silicon in the component is 21%. The silicon wafer has no pores, fissures or other gaps and is joined to the CMC composite in a firmly interlocking manner. This optically reflecting structure, with a density of 1.7 g/cm 3 , is polished briefly with a lapping machine to reduce the surface roughness to the required level.
In this method in accordance with the invention it is especially advantageous that the production of CMC and the reactive fixation or joining of the silicon wafer to the CFC blanks both occur in situ, thus forming extremely smooth structures that are subsequently coated.
EXAMPLE 4
A commercially available honeycomb material made of hard paper, with a relative weight of 0.2 g/cm 3 and a cell (inscribed circle) diameter of 6 mm is impregnated with a phenolic-resin binder and dried at 70° C.
To each face of a disk of the resulting honeycomb structure, measuring 400 mm in diameter and 10 mm in thickness, three layers of carbon-fiber web prepregs are now pressed on or laminated in a heatable press at 200° C.
The resulting CFC structure is carbonized by heating to 1000° C. in the absence of oxygen, with a heating rate of 2 kelvin per minute. After a holding time of 6 hours the structure is cooled to room temperature, producing a carbon-based honeycomb structure which, apart from a linear shrinkage of ca. 17%, corresponds to the original CFC component. The still-porous honeycomb structure is further strengthened by infiltration with pyrolyric carbon, performed by chemical vapor deposition as described in Examples 1 and 3. The component so obtained, with a relative weight of 0.22 g/cm 3 , has 4-point bending strengths of more than 150N/mm 2 .
One of the faces laminated with carbon-fiber web is superficially polished and two silicon wafers are glued to it. The resin binder used is a mixture of phenolic resin and silicon powder in the proportions 2:1 by weight.
This procedure is followed by silicon infiltration as described in Example 3, whereby the wafer is fixed to the honeycomb structure. The honeycomb-based mirror structure obtained after cooling, with a real weight per unit volume of 0.42 g/cm 3 , is illustrated in FIG. 7.
The resulting extremely light construction material is distinguished not only by its great rigidity and compression strength but also by low thermal conductivity. It is also particularly advantageous that the inner flexible honeycomb structures compensate for the expansion caused by thermal shock because of their thin walls, so that thermally induced fissures are kept to a minimum.
FIG. 5 shows how a large-area mirror can be put together from subunits. Here it is especially advantageous that basic elements consisting of silicon wafers 11 and substrate structures 10 of matching dimensions can be combined to produce mirrors of any desired size. The substrate structures 10 are held together by bridging units 14 (preferably of CFC material). If the presence of gaps between the individual elements is permissible, the mirror can be constructed of ready-made single reflectors. It is also possible, of course, to join the "blanks" to one another and subject them all together to the procedure described above, so that all the parts are fixed together.
In the embodiment shown in FIG. 5C, no bridging units 14 are necessary because the substrate structures 10 are so constructed as to form tongue-and-groove joints 15.
In the embodiment of the invention shown in the FIGS. 8, the CMC component forming the substrate structure 10 is provided with honeycomb-like recesses. Furthermore, in this sample embodiment three mounting recesses 117 are also included, into which connection pins or the like can be fixed to mount the finished mirror. The other reference numbers for this embodiment of the invention apply to the same parts as previously or to parts with the same function. Manufacture can be carried out as described above.
Another version of the method of the invention will now be described with reference to FIGS. 9 and 10.
As shown in FIG. 9A, the first step here is to coat a preform 11 of metallic silicon (a wafer) on the side opposite the reflecting surface 12 with a nonferrous metal, in particular with gold. This coating can be achieved by applying gold foil or by sputtering. The element so produced is shown in FIG. 9A.
This element is now heat-treated so that the gold layer 2 forms a melt eutectic with the silicon 11. This eutectic is indicated by the number 3 in FIG. 9B.
The element thus produced, shown in FIG. 9B, is now attached to the substrate structure 10, and then the whole apparatus is subjected to further heat treatment in a temperature range between 300° and 600° C. As a result, the upper (in FIG. 9C) silicon preform 11 becomes intimately joined to the lower substrate structure 10 over the whole region of the melt eutectic 3.
It is also possible to avoid a separate processing step for forming the melt eutectic on one surface of the wafer 11 (as in FIG. 9), by applying a wafer 11 directly to the substrate structure 10 with an intervening gold layer 2 (FIG. 10A). Then, in a single step, the two elements 10 and 11 are joined to one another by formation of a zone 3 of melt eutectic, as shown in FIG. 10B.
In this version of the method, the connection between the silicon preform (the wafer) and the substrate structure can be made at temperatures between about 300° and 600° C., whereas in the other versions of the method in accordance with the invention described above, the process temperatures are between ca. 900° and 1500° C. Furthermore, especially when gold is used as the nonferrous metal, it is possible to operate in a normal atmosphere and/or at normal pressure.
It will be appreciated from the above description that various steps of the method can readily be combined with one another. | 4y
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TECHNICAL FIELD
The instant invention is directed to a pre-treatment to liberate polysaccharide antigens from biological probes in order to enable the use of these antigens in immunological determinations.
BACKGROUND OF THE INVENTION
In practice, diverse methods are used to liberate the antigens, namely heating to 100° C., an enzymatic treatment at 37° C. or an extraction with sodium nitrite in two operational steps.
Another known procedure for the extraction of these antigens is a treatment with high-percentage phenol, e.g. 90% saturated phenol (90% phenol/10% water) at a temperature of 60° C.
The heating to 100° C. as well as the enzymatic treatment for the antigen liberation can not be effected in the presence of specific antibodies, since these are denatured. A re-pipetting must also be effected. The same applies in the case of a high-percentage phenol extraction, which additionally requires a centrifugation. The extraction with sodium nitrite involves two separate reagents and subsequent treatment with Tris buffer.
This means that these known procedures are extremely circumstantial and time consuming and are therefore anything but conformable in practice.
SUMMARY OF THE INVENTION
In the scope of the present invention there has now been found a method for the liberation of polysaccharide antigens from bacteria or fungi in biological probes or in grown cultures of these probes for the subsequent immunological determination of these antigens, which method comprises treating the biological probe or the grown culture with an aqueous phenol solution.
DETAILED DESCRIPTION
A 1-10% aqueous phenol solution can be used in the method in accordance with the present invention, with a 2-5% aqueous phenol solution being preferred and a 2% aqueous phenol solution being especially preferred.
Blood, serum, plasma, urine, faeces or sputum are suitable biological probes for the method in accordance with the present invention.
It has been found that in accordance with the method provided by the invention one part of aqueous phenol solution is used per 5 parts of biological probe or culture.
In the method in accordance with the present invention the aqueous phenol solution can be allowed to act on the probe or culture for 5-30 minutes, preferably for 15 minutes.
The temperature used in the pre-treatment is not critical. The pre-treatment is conveniently effected between 15° C. and up to just before the boiling point of the reaction mixture, with room temperature being especially preferred.
No extraction is necessary for the subsequent immunological determination of the polysaccharide antigens, which means that the immunological detection method can be carried out in the medium in which the liberation of the antigens has been effected.
The aforementioned immunological detection method can be effected in a manner known per se, especially according to the so-called ELISA technique.
The method in accordance with the present invention is excellently suited to the detection of polysaccharide antigens from streptococci, especially from Streptococcus pneumoniae, from mycobacteria, especially Mycobacterium tuberculosis, or from enterobacteriaceae, especially Escherichia coli.
In the scope of the present invention it has furthermore been found that the method in accordance with the invention not only requires less intensive work, but in most cases also offers an improved sensitivity with respect to the determination of the polysaccharide antigens.
The following Examples illustrate the invention.
EXAMPLE 1
A) ELISA test methodology
A.1.) Qualitative determination of mycobacteria antigens in culture-grown bacteria and body fluids with mycobacteria antibodies from rabbits.
Into each of the requisite number of test tubes (10×25 mm) there is pipetted 0.25 ml of probe material (bacterial suspension, serum, liquified sputum, urine), and thereto there is added 0.05 ml of the reaction reagent (phenol or NaNO 2 +acetic acid+Tris buffer) or H 2 O. After adding an anti-mycobacteria-sensitized polystyrene bead (φ=6.5 mm) to each test tube the batch is incubated at room temperature for 30 minutes. Subsequently, without a washing operation, 0.25 ml of rabbit-anti-mycobacteria-peroxidase conjugate (0.1M tris-hydroxymethyl-aminomethane, pH 7.0 inactivated with 20% foetal calf serum, 0.05% Tween 20 and 3 μg/ml of rabbit-anti-mycobacteria-peroxidase conjugate) is added. Thereafter, the batch is incubated at room temperature for 4 h. After the incubation period the polystyrene beads are washed twice in an EIA washer <Roche> with in each case 5 ml of twice-dist. water. Thereafter, there is added to each of the test tubes 0.25 ml of substrate buffer in order to determine the activity of the peroxidase (0.1 mol/l potassium citrate buffer of pH 5.2 with 6 mmol/l H 2 O 2 and 20 mmol/l o-phenylenediamine) and incubation is carried out at room temperature for 15 min. In order to stop the peroxidative activity and to intensify the colour intensity 1.0 ml of 1N H 2 SO 4 is added and the extinction at the wavelength 492 nm is measured photometrically within 30 minutes, e.g. with the EIA photometer <Roche>.
A.2) Qualitative determination of pneumococci antigens to culture-grown bacteria and body fluids with pneumococci antibodies from rabbits.
Into each of the requisite number of test tubes (10×25 mm) there is pipetted 0.25 ml of probe material (bacterial suspension or serum, liquified sputum, urine) or PBS (blank) and thereto there is added 0.05 ml of the reaction reagent (phenol or NaNO 2 +acetic acid+Tris buffer) or H 2 O. After adding an anti-pneumococci-sensitized polystyrene bead (φ=6.5 mm) to each test tube the batch is incubated at room temperature for 15 minutes. Subsequently, without a washing operation, 0.25 ml of rabbit-anti-pneumococci-peroxidase conjugate (0.1M tris-hydroxymethyl-aminomethane, pH 7.0 inactivated with 20% foetal calf serum, 0.05% Tween 80 and 0.7 μg/ml rabbit-anti-pneumococci-peroxidase conjugate) is added. Thereafter, the batch is incubated at room temperature for 60 minutes. After the incubation period the polystyrene beads are washed twice in an EIA washer <Roche> with in each case 5 ml of twice-dist. water. Thereafter, there is added to each of the test tubes 0.25 ml of substrate buffer in order to determine the activity of the peroxidase (80 mmol/l potassium citrate buffer pH 4.25 with 1.6 mmol/l H 2 O 2 and 1 mmol/l 3,3',5,5'-tetramethylbenzidine in 13.4% DMSO with 6.6% 2-propanol) and the test tubes are held at room temperature for 5 minutes. In order to stop the peroxidative activity and to intensify the colour intensity there is added 1.0 ml of 1N H 2 SO 4 and the extinction at the wavelength 450 nm is measured photometrically within 30 minutes, e.g. with the EIA photometer <Roche>.
A.3.) Qualitative determination of E. coli antigens in culture-grown bacteria and body fluids with E. coli antibodies from rabbits
Into each of the requisite number of test tubes (10×25 mm) there is pipetted 0.25 ml of probe material (bacterial suspension or serum, urine) or PBS (blank), and thereto there is added 0.05 ml of the reaction reagent (phenol or NaNO 2 +acetic acid+Tris buffer) or PBS. After adding an anti-E. coli-sensitized polystyrene bead (φ=6.5 mm) to each test tube the batch is incubated at room temperature for 15 minutes. Subsequently, without a washing operation, 0.25 ml of rabbit-anti-E. coli-peroxidase conjugate (0.1M trishydroxymethylaminomethane, pH 7.0 inactivated with 20% foetal calf serum, 0.05% Tween 20 and 1 μg/ml rabbit-anti-E. coli-peroxidase conjugate) is added. Thereafter, the batch is incubated at RT for 30 minutes. After the incubation period the polystyrene beads are washed twice in an EIA washer <Roche> with in each case 5 ml of twice-dist. water. Thereafter, there is added to each of the test tubes 0.25 ml of substrate buffer in order to determine the activity of the peroxidase (0.1 mol/l potassium citrate buffer of pH 5.2 with 6 mmol/l H 2 O 2 and 20 mmol/l o-phenylenediamine) and incubation is carried out at room temperature for 15 min. In order to stop the peroxidative activity and to intensify the colour intensity 1.0 ml of (1N) H 2 SO 4 is added and the extinction at the wavelength 492 nm is measured photometrically within 30 minutes, e.g. with the EIA photometer <Roche>.
EXAMPLE 2
B. Liberation of antigens from culture-grown bacteria
B.1.) Mycobacterium Calmette Guerin (BCG).
Several test tubes containing Middlebrook agar of the firm Difco were inoculated from a freshly opened ampoule of BCG vaccine from the Serum Institute Berne. After incubation for about 1 week the colonies were washed with physiological NaCl solution and adjusted to a McFarland density of about 0.5.
The suspension was divided into 5 equal parts and subjected to the various pre-treatments: thereafter in each case a one-step enzyme immunoassay was carried out. The performance of the test was effected in accordance with Example 1.
The following results were obtained:
__________________________________________________________________________Mycobacterium Calmette Guerin (BCG) Treatment period 15 minutes 30 minutes Calculation Type of treatment OD probe - OD blank ##STR1## OD probe - OD blank ##STR2##__________________________________________________________________________ 250 μl probe + 50 μl H.sub.2 O 0.794 5.1 0.842 5.8250 μl probe + 50 μl 1% phenol 1.145 7.4 1.186 8.2250 μl probe + 50 μl 2% phenol 1.608 9.8 1.731 10.8250 μl probe + 50 μl 2.5% phenol 1.612 11.2 1.764 12.3250 μl probe + 300 μl H.sub.2 O n.d. n.d. 0.156 2.0250 μl probe + 100 μl NaNO.sub.2 1M n.d. n.d. 0.130 1.8+ 100 μl acetic acid 1M+ 100 μl Tris buffer*__________________________________________________________________________ *The Tris buffer was added in each case 15 minutes after the reagents had taken effect.
B.2.) Pneumococci
Streptococcus pneumoniae was grown overnight on blood plates. Thereafter, a suspension of the colonies in physiological NaCl solution having the McFarland density 1.0 was prepared. The suspension was divided into 5 equal parts and the various pre-treatments were carried out. The one-step enzyme immunoassay was subsequently carried out. The performance of the test was effected as in Example 1.
The following results were obtained:
______________________________________Pneumococci - positive sputum Treatment period 30 minutes RT Calculation Type of treatment OD probe - OD blank ##STR3##______________________________________ 250 μl probe + 50 μl H.sub.2 O 0.028 9.2250 μl probe + 50 μl 5% phenol 2.261 26.1250 μl probe + 50 μl H.sub.2 O 100° C. 1.232 13.7250 μl probe + 1 gH NaNO.sub.2 1M 1.912 18.9+ 1 gH acetic acid1M+ 1 gH Tris buffer*______________________________________ *The Tris buffer was added in each case 15 minutes after the reagents had taken effect.
B.3.) Escherichia coli
E. coli ATCC 19110 was grown overnight on blood plates. Thereafter a suspension of the colonies in physiological NaCl solution with the McFarland density 1.0 was prepared. The suspension was divided into 4 equal parts and subjected to the various pre-treatments. Thereafter, in each case a one-step enzyme immunoassay was carried out. For the performance of the test see under methodology.
The following results were obtained:
______________________________________ Treatment period 15 minutes RT Calculation Type of treatment OD probe - OD blank ##STR4##______________________________________ 250 μl probe + 50 μl H.sub.2 O 2.166 12.2250 μl probe + 50 μl 2% phenol 1.950 11.5250 μl probe + 50 μl 5% phenol 2.096 14.8250 μl probe + 50 μl H.sub.2 O 100° C. 1.841 10.5250 μl probe + 60 μl reagent mix 2.100 11.3(NaNO.sub.2, acetic acid, Tris buffer*)______________________________________ *The Tris buffer was added in each case 15 minutes after the reagents had taken effect.
EXAMPLE 3
C. Liberation of antigens in infectious investigational material
The further investigations were carried out on material from patients. The one-step EIA test was carried out in accordance with Example 1. The pre-treatments were effected according to the attached Scheme.
__________________________________________________________________________Scheme of parallel investigations with different pre-treatments: Pre-treatment Reagent None 100° C. 15 min Phenol 2% Phenol 5% mixture L P L P L P L P L PBatch μl μl μl μl μl μl μl μl μl μl__________________________________________________________________________Probe - 250 - 250 - 250 - 250 - 250PBS 250 - 250 - 250 - 250 - 250 -H.sub.2 O twice dist. 50 50 50 50 - - - - - -Phenol 2% - - - - 50 50 - - - -Phenol 5% - - - - - - 50 50 - -NaNO.sub.2 0.1M - - - - - - - - 20 20CH.sub.3 COOH 0.1M - - - - - - - - 20 20Incub. 15 min, RT - - - - - - - - x xTris buffer 0.14 - - - - - - - - 20 20Ab-loaded bead + + + + + + + + + +Pre-incubation + + + + + + + + + +Conjugate 250 250 250 250 250 250 250 250 250 250Immunol. incubation + + + + + + + + + +Washing + + + + + + + + + +Substrate solution 250 250 250 250 250 250 250 250 250 250Incubation + + + + + + + + + +Stop reagent + + + + + + + + + +__________________________________________________________________________ L = Blank (PBS) P = Probe
The following results were obtained:
______________________________________C.1.) Mycobacterium - positive sputum Calculation Type of treatment OD probe - OD blank ##STR5##______________________________________ Negative sputum -0.068 0.7Untreated sputum 0.153 1.6Sputum + 2% phenol 1.100 6.8Sputum 100° C. 0.535 3.3Sputum + NaNO.sub.2 0.464 2.7Acetic acid, Tris______________________________________
______________________________________C.2.) Pneumococci - positive sputum Calculation Type of treatment OD probe - OD blank ##STR6##______________________________________ Negative sputum -0.070 0.7Untreated sputum 1.209 7.3Sputum + 2% phenol 1.072 6.8Sputum + 5% phenol 1.081 8.1Sputum 100° C. 1.110 6.8Sputum + NaNO.sub.2 1.052 6.2Acetic acid, Tris______________________________________
__________________________________________________________________________C.3.) E. coli - positive urineType of calculation OD probe - OD blank ##STR7##Type of treatmentUrine Untreated 2% Phenol 5% Phenol 100° C. Untreated 2% Phenol 5% Phenol 100° C.__________________________________________________________________________U 7224 0.021 0.124 0.215 0.164 1.5 3.7 3.6 4.5U 7231 0.026 0.133 0.311 0.193 1.6 3.7 4.7 4.9U 7261 0.093 0.160 0.233 0.068 3.1 4.7 4.2 2.4U 7282 0.101 0.197 0.347 0.181 2.6 4.0 4.9 3.9U 7286 0.271 0.419 0.823 0.300 5.3 7.4 10.2 5.8U 7293 0.057 0.112 0.190 0.250 1.9 2.9 2.8 5.3__________________________________________________________________________ | 4y
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BACKGROUND OF THE INVENTION
The present invention relates to thermostats, and more particularly to a temperature responsive, fluid control valve for pneumatic control systems that performs multiple control functions.
Thermostats for pneumatic control systems are generally of the type that have a temperature responsive expansible element connected to a valve that opens or closes a port to either apply pressurized control fluid to an element to be operated or to bleed pressurized control fluid from that element. It is a broad object of the present invention to provide an improved thermostat for pneumatic control systems that can perform multiple control functions upon a single throw of a temperature responsive expansible element. More particularly, it is an object of the present invention to provide a thermostat for a pneumatic control system that can vary control pressure to two or more elements to be controlled, simultaneously or sequentially, inversely or directly proportional to a temperature change, and, linearly or nonlinearly with respect to a change in temperature.
SUMMARY OF THE INVENTION
In accordance with the foregoing objects, and other objects that will become apparent to one of ordinary skill after reading the following specification, the present invention provides a thermostatic valve for a pneumatic control system that includes a temperature-responsive expansible element, a cylinder, and a piston mounted for reciprocation in the cylinder. The piston is coupled to the temperature-responsive expansible element so as to move in the cylinder in reaction to expansion and contraction of that element. The cylinder has first and second control fluid ports and at least a third control fluid port axially spaced from the first and second ports. The piston has first and second fluid passages therein. One end of each of these passages communicates between respective first and second, preselected locations on the piston wall and one end of the piston. The preselected locations are positioned relative to the first and second control fluid ports in the cylinder wall so that as the piston moves in the cylinder, these ends of the passages will be placed in selective communication with the first and second control fluid ports while the other ends of the passages will be placed in communication with the third control fluid port.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the present invention can be derived by reading the ensuing specification in conjunction with the accompanying drawings wherein:
FIG. 1 is an elevation view in cross section of the thermostatically controlled valve for a pneumatic control system constructed in accordance with the present invention having two control ports and showing both control ports closed;
FIG. 2 is a view similar to FIG. 1 showing one of the control ports opened;
FIG. 3 is a view similar to FIG. 1 showing both of the control ports opened;
FIG. 4 is a view of the piston-shaped valve member taken along a line similar to view line 4--4 of FIG. 1; and
FIG. 5 is a view of the piston-shaped valve member taken along a view line similar to 5--5 in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, one embodiment of the thermostatically controlled valve 10 is illustrated. The three major elements of the valve are an elongated cylindrical shell 12, a temperature-responsive bellows 14, and a piston 16. The bellows 14 is of conventional construction and comprises a fluted expansible member with a fluid hermetically sealed between the bellows and the wall of the shell 12. The fluid has a high coefficient of expansion, thus causing the bellows assembly to expand and contract along its axis in response to changes in temperature. One end 14a of the bellows is affixed to the shell at a location spaced from the lower end 12a of the cylindrical shell. The other end 14b of the bellows is positioned between the first end 14a and the lower end 12a of the shell. This end of the cylindrical shell 12 is inserted into a fluid stream, the temperature of which is to be sensed. Fluid flowing past the thermally conductive surface of the shell 12 causes the fluid between the shell and the bellows to expand or contract as the case may be. A piston rod 20 is affixed to the other end 14b of the bellows assembly 14 and extends upwardly through the bellows 14 and slidably through a divider 22 mounted in the central portion of the cylindrical assembly. The piston rod thus can reciprocate in the divider in reaction to expansion and contraction of the bellows assembly 14.
The piston 16 is mounted for reciprocation in the end of the cylindrical shell that is on the opposite side of the divider 22 from the bellows 14. The upper end of the cylinder carries a piston ring 24 that seals the upper end of the piston against the walls of the cylinder assembly. An end cap 25 threadably engages the end of the cylindrical shell 12 adjacent the piston 16. A spring 26 is interposed between the end cap 25 and the top of the piston 16 so as to bias the piston in a downward direction against the upwardly directed expansion force of the bellows 14 to assist the bellows in retracting upon a reduction in temperature of the sensed fluid. Ports 28 are located in the cylindrical shell between the end cap 25 and the upper end of the piston 16. The ports 28 are provided to equalize the pressure in the upper end of the shell 12 with that of the atmosphere so that pressure variances in the upper end of the shell 12 do not inhibit free movement of the piston 16. First and second control ports 30 and 32 are positioned in the side walls of the cylindrical shell 12 below but adjacent the upper surface 16a of the piston 16. Control port 30 is coupled to a conduit 34 containing a flow restrictor 36. Conduit 34 is coupled to a source (not shown) of pressurized control fluid. Another conduit 38 is coupled to the first conduit 34 between the control port 30 and the restrictor 36. The other end of the conduit 38 is coupled to a device (not shown) to be controlled by an increase and decrease in the control pressure present in conduit 38. Similarly, the control port 32 is coupled to another conduit 40 containing a restrictor 42. The conduit 40 is in turn coupled to a source (not shown) of pressurized control fluid. Another conduit 44, coupled to a second device (not shown) to be controlled, is in turn coupled to the conduit 40 between the control port 32 and the restrictor 42.
Referring now to FIGS. 1 and 4, a passage 46 is formed on one of the sides of the piston 16. Passage 46 is notched into the side of the piston 16 so that in this embodiment, the notch begins at a triangular apex 46a spaced axially downwardly from the upper surface 16a of the piston 16. The bottom end 46b of the passage communicates along the side of the piston with the bottom of the piston. Referring to FIG. 5, a similar passage 48 is formed on the opposite side of the piston 16. The apex 48a of the passage 48 is, however, positioned axially further down the side of the piston than was the apex 46a of the passage 46. Likewise, the bottom 48b of the passage 48 communicates with the bottom end of the piston.
Referring back to FIG. 1, piston 16 is shown in a lowermost position corresponding to a given low temperature. In this position, both control ports 30 and 32 are blocked by the upper reaches of the piston 16. As the temperature of the fluid surrounding the shell 12 increases, the bellows 14 will be foreshortened, exerting an upward force on the piston rod 20 and thus raising the piston 16 upwardly against the biasing force of spring 26 toward the position as shown in FIG. 2. As the piston 16 rises to this position, the apex 46a of the passage 46 is circumferentially positioned on the piston 16 such that it passes across control port 30. As it does, the pressurized control fluid present in conduit 38 is bled through passage 46 and vented to the atmosphere through ambient vents 50 in the side wall of the cylindrical shell 12 below the piston 16. Similarly, as the temperature continues to increase, the piston rises further toward the position shown in FIG. 3. The apex 48a of the other passage 48 is circumferentially positioned on the piston 16 such that it passes across the control port 32, thus bleeding pressurized control fluid from the conduit 44 through passage 48. In this manner, the elements to be controlled by the pressurized control fluid in conduits 38 and 44 can be actuated in response to a temperature change sensed by the fluid surrounding the bellows 14.
As the temperature of the fluid surrounding the shell 12 decreases, the bellows will increase in length under the influence of the biasing spring 26. As it does so, the piston 16 travels downwardly first closing control port 32 then control port 30. When the ports are closed, control fluid pressure once again rises in the conduits 44 and 38 to actuate the devices being controlled.
One of ordinary skill will be able to effect various changes, substitutions of equivalents, and other alterations without departing from the broad concepts disclosed. For example, the rate and linearity of bleed-off of pressurized control fluid through the control ports can be varied by varying or changing the shape of the passage 46. The passages illustrated in connection with the disclosed embodiment initially provide for a slow bleed-off that increases in rate as the temperature increases. If a faster initial control fluid bleed were desired, the passages can be shaped so that a greater area of the control port is initially exposed as the piston rises. As another example, with relatively simple plumbing modifications, the control valve of the present invention can be utilized to cause an increase in control fluid pressure at the device to be controlled in resopnse to a rise in temperature. It is also possible by varying the locations of the passages 46 and 48 to provide for simultaneous control of a plurality of devices, or to vary the interval between control of the devices in response to temperature changes. And as a last example, any desired number of devices can be controlled by increasing the number of passages and corresponding control parts. It is accordingly intended that the scope of Letters Patent granted hereon be limited only by the definition contained in the appended claims and equivalents thereof. | 4y
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 10/093,114, filed Mar. 7, 2002 now U.S Pat. No. 6,617,666, the entire contents of which are incorporated by reference, and which is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2001-065253, filed Mar. 8, 2001, the entire contents of which are incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device with an MIM (Metal Insulating Metal) capacitor, and a process for manufacturing the semiconductor device.
2. Description of the Related Art
Semiconductor devices provided with Cu wiring of a damascene structure and MIM capacitors are now available.
FIG. 28 is a sectional view of a conventional semiconductor device. As shown in FIG. 28 , a via hole 43 and a wire 44 , which are made of, for example, Cu, are provided in a film 41 of a low dielectric constant and a film 42 of a high dielectric constant. A Cu-diffusion-preventing film 45 is provided on the high dielectric film 42 and wire 44 , and a capacitor 49 is provided on a selected portion of the Cu-diffusion-preventing film 45 . The capacitor 49 is formed of a lower electrode 46 , a dielectric film 47 and an upper electrode 48 . An insulating film 50 is provided on the capacitor 49 and Cu-diffusion-preventing film 45 . The surface of the insulating film is flattened by CMP (Chemical Mechanical Polishing).
In such conventional semiconductor devices, it is desirable that the insulating film 50 be formed of a low dielectric film in order to reduce the parasitic capacitance between wires.
However, since the low dielectric film is a rough film, a crack may occur if the surface of the film is flattened. Therefore, it is very difficult to level, by CMP, the surface of an insulating film 50 formed of a low dielectric film. To avoid this, a high dielectric film could be used as the insulating film 50 , as thus would reduce the formation of cracks under CMP.
However, since the capacitor 49 is provided on a selected portion of the Cu-diffusion-preventing film 45 , there is a step corresponding to the thickness of the capacitor 49 between the area provided with the capacitor and the area without. To eliminate the step caused by the presence of the capacitor 49 , it is necessary to form an insulating film 50 in the area with no capacitor on the Cu-diffusion-preventing film 45 . Thus, as stated above, a high dielectric film or insulating film 50 is provided on the film 45 to surround the capacitor 49 . The provision of the high dielectric insulating film 50 to fill the step caused by the capacitor 49 inevitably increases the parasitic capacitance between wiring layers.
As described above, in the conventional semiconductor device, it is very difficult to level the surface of the insulating film 50 by CMP.
BRIEF SUMMARY OF THE INVENTION
According to a first aspect of the present invention, there is provided a semiconductor device comprising: a first insulating film comprising an opening; a capacitor formed at a selected position in the opening; a second insulating film formed at least in the opening; and a third insulating film formed on the second insulating film.
According to a second aspect of the present invention, there is provide a process of manufacturing a semiconductor device, comprising: forming a first insulating film; removing a selected portion of the first insulating film, thereby forming an opening; forming a capacitor at a selected position in the opening; forming a second insulating film at least in the opening; and forming a third insulating film on the second insulating film.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIGS. 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 and 9 are sectional views illustrating the steps of a process for manufacturing a semiconductor device according to a first embodiment of the invention;
FIG. 10 is a plan view illustrating the semiconductor device according to the first embodiment of the invention;
FIGS. 11 , 12 and 13 are sectional views illustrating the steps of a process for manufacturing another semiconductor device according to the first embodiment of the invention;
FIGS. 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 and 22 are sectional views illustrating the steps of a process for manufacturing a semiconductor device according to a second embodiment of the invention;
FIGS. 23 , 24 and 25 are sectional views illustrating the steps of a process for manufacturing another semiconductor device according to the second embodiment of the invention;
FIGS. 26 and 27 are sectional views illustrating another semiconductor device according to the first and second embodiment of the invention; and
FIG. 28 is a sectional view illustrating a conventional semiconductor device.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in detail to the presently embodiments of the invention as illustrated in the accompanying drawings, in which like reference characters designate like or corresponding parts in all drawings.
In the embodiments of the invention, a “low dielectric film” means a film having a relative dielectric constant of about 4.0 or more, while a “high dielectric film” means a film having a higher relative dielectric constant than a low dielectric film.
[First Embodiment]
In a first embodiment of the invention, an opening is provided in an insulating film, i.e., a low dielectric film, and an MIM (Metal Insulating Metal) capacitor is formed in the opening.
FIGS. 1-9 are sectional views illustrating the steps of a process for manufacturing a semiconductor device according to the first embodiment. A description will now be given of the process for manufacturing the semiconductor device according to the first embodiment.
Firstly, as shown in FIG. 1 , a high dielectric film 12 having a higher relative dielectric constant than a low dielectric film 11 is formed on the low dielectric film 11 . Subsequently, using a damascene process, a via hole 13 and a first wire 14 , which are made of, for example, Cu, are formed in the low and high dielectric films 11 and 12 . Thereafter, a Cu-diffusion-preventing film 15 made of, for example, SiN is formed on the first wire 14 and high dielectric film 12 by sputtering. An insulating film 16 as a low dielectric film is formed on the Cu-diffusion-preventing film 15 . The thickness of the insulating film 16 is formed to, for example, 270 nm.
Referring to FIG. 2 , the insulating film 16 is coated with a resist film 17 , which is patterned by lithography. Using the patterned resist film 17 as a mask, the insulating film 16 is patterned by RIE (Reactive Ion Etching), thereby forming an opening 18 . Then, the resist film 17 is removed.
Referring to FIG. 3 , a lower electrode film 19 made of, for example, TiN is formed in the opening 18 and on the insulating film 16 by sputtering, and a dielectric film 20 made of, for example, Ta 2 O 2 is formed on the lower electrode film 19 . Further, an upper electrode film 21 made of, for example, TiN is formed on the dielectric film 20 . The thicknesses of the lower electrode film 19 , dielectric film 20 and upper electrode film 21 are formed to, for example, 60 nm, 50 nm and 50 nm, respectively.
Referring to FIG. 4 , the upper electrode film 21 is coated with a resist film 22 , which is patterned by lithography. After that, using the patterned resist film 22 as a mask, the upper electrode film 21 is patterned by RIE such that it remains in the opening 18 . Then, the resist film 22 is removed.
Referring to FIG. 5 , the upper electrode film 21 and dielectric film 20 are coated with a resist film 23 , which is patterned by lithography. After that, using the patterned resist film 23 as a mask, the dielectric film 20 and lower electrode film 19 are patterned by RIE such that they have surface areas larger than that of the upper electrode film 21 , and remain in the opening 18 . As a result, an MIM capacitor 24 , composed of the lower electrode film 19 , dielectric film 20 and upper electrode film 21 , is formed in the opening 18 . Then, the resist film 23 is removed.
Referring to FIG. 6 , a first interlayer film 25 is formed in the opening 18 and on the insulating film 16 by PECVD (Plasma Enhanced Chemical Vapor Deposition). The first interlayer film 25 is a high dielectric film form of SiO 2 , for example. However, the film 25 is not limited to a high dielectric film, as long as it is an insulating film that is formed at a low temperature and can be subjected to CMP.
Referring to FIG. 7 , the first interlayer film 25 is flattened by CMP (Chemical Mechanical Polishing) until the surface of the insulating film 16 is exposed. At this time, it is desirable that a marginal interlayer portion X of about 500 Å to 1000 Å be left on the capacitor 24 so that the surface of the capacitor 24 will not be exposed. In other words, it is sufficient if the capacitor 24 , composed of the lower electrode film 19 , dielectric film 20 and upper electrode film 21 , is made thinner than the insulating film 16 .
Referring to FIG. 8 , a second interlayer film 26 is formed on the first interlayer film 25 and insulating film 16 , and a third interlayer film 27 is formed on the second interlayer film 26 . The second interlayer film 26 is a low dielectric film such as an FSC (fluorine Spin Glass) film, while the third interlayer film 27 is a high dielectric film, formed of SiO 2 , for example.
Referring to FIG. 9 , the first, second and third interlayer films 25 , 26 and 27 , etc. are removed to form via holes and grooves for wires. Thereafter, a barrier metal layer (not shown) is deposited in via holes and wire grooves, and is plated with a Cu film. The barrier metal layer and Cu film are flattened by CMP, thereby forming via holes 28 a, 28 b and 28 c and second wires 29 a, 29 b and 29 c. The via hole 28 a and second wire 29 a are connected to the lower electrode film 19 on the capacitor 24 , the via hole 28 b and second wire 29 b are connected to the upper electrode film 21 on the capacitor 24 , while the via hole 28 c and second wire 29 c are connected to the first wire 14 . Subsequently, a Cu-diffusion-preventing film 30 is formed on the third interlayer film 27 and second wires 29 a, 29 b and 29 c.
FIG. 10 is a plan view illustrating the semiconductor device according to the first embodiment of the invention. As shown in FIG. 10 , the opening 18 is formed in the insulating film 16 , and the capacitor 24 is formed in the opening 18 . As a result, the capacitor 24 is surrounded by the insulating film 16 , and the first interlayer film 25 is formed in a clearance in the opening 18 . FIG. 7 is a sectional view taken along line VII—VII of FIG. 10 .
In the above-described first embodiment, the first interlayer film 25 on the capacitor 24 is a film (e.g. a high dielectric film) that does not easily crack even if it is subjected to CMP. Accordingly, the surface of the first interlayer film 25 on the capacitor 24 can be flattened by CMP.
Further, since the opening 18 is formed in the insulating film 16 and receives the capacitor 24 , the insulating film 16 surrounds the capacitor 24 . Thus, the first interlayer film 25 as a high dielectric film is provided only in the opening 18 , which further reduces the parasitic capacitance between the wires.
Also, the second interlayer film 26 as a low dielectric film is mostly formed around the via holes 28 a, 28 b and 28 c and second wires 29 a, 29 b and 29 c, the parasitic capacitance between the wires can be further reduced.
Furthermore, the provision of the insulating film 16 around the capacitor 24 enables the step due to the capacitor 24 to be reduced. In other words, when the first interlayer film 25 is formed on the capacitor 24 , the shape of the capacitor 24 does not significantly influence the first interlayer film 25 . Accordingly, the surface of the first interlayer film 25 on the capacitor 24 can be more easily flattened than in the conventional case.
Also, since the insulating film 16 is a low dielectric film, the parasitic capacitance between the wires can be further reduced.
Moreover, the Cu-diffusion-preventing film 15 provided under the capacitor 24 prevents Cu from diffusing from the second wires 29 a, 29 b and 29 c and via holes 28 a, 28 b and 28 c into an element (not shown) located below and contaminating it.
Further, the margin X prepared for flattening the first interlayer film 25 by CMP prevents the surface of the capacitor 24 from being damaged, thereby enhancing the performance of the capacitor 24 .
The first interlayer film 25 may be an organic insulating film formed by coating. In this case, the surface of the organic insulating film can be substantially flattened when it is coated, and therefore, the leveling process using CMP shown in FIG. 7 can be omitted. This means that a low dielectric film can be used as the first interlayer film 25 , which cannot be realized in light of the process of CMP in the prior art. Thus, the use of a coating-type film as the first interlayer film 25 can reduce the capacitance between the wires, as well as the number of required process steps.
In addition, if the surface of the first interlayer film 25 is sufficiently flattened by CMP in the process of FIG. 7 , it is not necessary to level the first interlayer film 25 until the surface of the insulating film 16 is exposed. However, the thinner the remaining portion of the first interlayer film 25 as a high dielectric film, the lower the capacitance between the wires. In light of this, it is desirable to level the first interlayer film 25 until the surface of the insulating film 16 is exposed.
In the first embodiment, another Cu-diffusion-preventing film may be formed on the capacitor 24 to protect it. In this case, at first, the capacitor 24 is formed as shown in FIG. 5 . Subsequently, a Cu-diffusion-preventing film 31 is formed on the capacitor 24 and insulating film 16 , and the first interlayer film 25 is formed on the Cu-diffusion-preventing film 31 , as is shown in FIG. 11 . Then, the first interlayer film 25 is flattened by CMP until the surface of the insulating film 16 is exposed, as is shown in FIG. 12 . After that, the structure as shown in FIG. 13 is formed by process steps similar to those of the first embodiment. In this structure, the Cu-diffusion-preventing film 31 on the capacitor 24 prevents Cu from diffusing from the second wires 29 a, 29 b and 29 c and via holes 28 a, 28 b and 28 c into the dielectric film 20 of the capacitor 24 and contaminating it.
[Second Embodiment]
In a second embodiment, the insulating film having the opening is a Cu-diffusion-preventing film.
FIGS. 14 to 22 are sectional views illustrating a process for manufacturing a semiconductor device according to the second embodiment. The process of manufacturing the semiconductor device of the second embodiment will be described. In this process, only steps differing from those of the first embodiment will be described.
Referring first to FIG. 14 , a via hole 13 and a first wire 14 , which are made of, for example, Cu, are formed in low and high dielectric films 11 and 12 , as in the first embodiment. Thereafter, a Cu-diffusion-preventing film 15 made of, for example, SiN is formed on the first wire 14 and high dielectric film 12 by sputtering. The thickness of the Cu-diffusion-preventing film 15 is formed to, for example, 270 nm.
Referring to FIG. 15 , the Cu-diffusion-preventing film 15 is coated with a resist film 17 , which is patterned by lithography. Using the patterned resist film 17 as a mask, the Cu-diffusion-preventing film 15 is patterned by RIE, thereby forming an opening 18 . Then, the resist film 17 is removed.
Referring to FIG. 16 , a lower electrode film 19 made of, for example, TiN is formed in the opening 18 and on the Cu-diffusion-preventing film 15 by sputtering, and a dielectric film 20 made of, for example, Ta 2 O 2 is formed on the lower electrode film 19 . Further, an upper electrode film 21 made of, for example, TiN is formed on the dielectric film 20 . The thicknesses of the lower electrode film 19 , dielectric film 20 and upper electrode film 21 are set to, for example, 60 nm, 50 nm and 50 nm, respectively.
Referring to FIG. 17 , the upper electrode film 21 is coated with a resist film 22 , which is patterned by lithography. After that, using the patterned resist film 22 as a mask, the upper electrode film 21 is patterned by RIE such that it remains in the opening 18 . Then, the resist film 22 is removed.
Referring to FIG. 18 , the upper electrode film 21 and dielectric film 20 are coated with a resist film 23 , which is patterned by lithography. After that, using the patterned resist film 23 as a mask, the dielectric film 20 and lower electrode film 19 are patterned by RIE such that they have surface areas larger than that of the upper electrode film 21 and remain in the opening 18 . As a result, an MIM capacitor 24 , composed of the lower electrode film 19 , dielectric film 20 and upper electrode film 21 , is formed in the opening 18 . Then, the resist film 23 is removed.
Referring to FIG. 19 , a first interlayer film 25 is formed in the opening 18 and on the Cu-diffusion-preventing film 15 by PECVD. The first interlayer film 25 is a high dielectric film formed of SiO 2 , for example. However, the film 25 is not limited to a high dielectric film, as long as it is an insulating film that is formed at a low temperature and can be subjected to CMP.
Referring to FIG. 20 , the first interlayer film 25 is flattened by CMP until the surface of the Cu-diffusion-preventing film 15 is exposed. At this time, it is desirable that a marginal interlayer portion X of about 500 Å to 1000 Å be left on the capacitor 24 so that the surface of the capacitor 24 will not be exposed. In other words, it is sufficient if the capacitor 24 , composed of the lower electrode film 19 , dielectric film 20 and upper electrode film 21 ,is made thinner than the Cu-diffusion-preventing film 15 .
Referring to FIG. 21 , a second interlayer film 26 is formed on the first interlayer film 25 and Cu-diffusion-preventing film 15 , and a third interlayer film 27 is formed on the second interlayer film 26 . The second interlayer film 26 is a low dielectric film such as an FSC film, while the third interlayer film 27 is a high dielectric film formed of SiO 2 , for example.
Referring to FIG. 22 , via holes 28 a, 28 b and 28 c and second wires 29 a, 29 b and 29 c are formed, and then a Cu-diffusion-preventing film 30 is formed, as in the first embodiment.
The above-described second embodiment can provide the same advantages as the first embodiment.
Further, in the second embodiment, the opening 18 is formed in the Cu-diffusion-preventing film 15 . In other words, the Cu-diffusion-preventing film 15 is used instead of providing a film dedicated to the formation of the opening 18 therein (which corresponds to the insulating film 16 in the first embodiment). Accordingly, the second embodiment requires a smaller number of process steps than the first embodiment.
In the second embodiment, another Cu-diffusion-preventing film may be formed on the capacitor 24 to protect it. In this case, at first, the capacitor 24 is formed as shown in FIG. 18 . Subsequently, a Cu-diffusion-preventing film 31 is formed on the capacitor 24 and Cu-diffusion-preventing film 15 , and the first interlayer film 25 is formed on the Cu-diffusion-preventing film 31 , as is shown in FIG. 23 . Then, the first interlayer film 25 is flattened by CMP until the surface of the Cu-diffusion-preventing film 15 is exposed, as is shown in FIG. 24 . After that, the structure as shown in FIG. 25 is formed by process steps similar to those of the second embodiment. In this structure, the Cu-diffusion-preventing film 31 on the capacitor 24 prevents Cu from diffusing from the second wires 29 a, 29 b and 29 c and via holes 28 a, 28 b and 28 c into the dielectric film 20 of the capacitor 24 and contaminating it.
As shown in FIG. 26 , the Cu-diffusion-preventing film 15 as a high dielectric film and the insulating film 16 as a low dielectric film are provided, and the opening 18 may be formed in these films.
Also, as shown in FIG. 27 , the Cu-diffusion-preventing film 31 may be formed on the capacitor 24 to protect it.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. | 4y
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to solid refuse disposal, and more particularly to a vertical shaft-hearth type furnace for converting pelletized refuse into useful gaseous product and inert solid residue.
2. Description of the Prior Art
Anderson U.S. Pat. No. 3,729,298 describes a solid refuse disposal process which has as products a useful fuel or synthesis gas and an inert solid residue. The Anderson process involves the introduction of refuse into the top of a vertical shaft, refractory-lined furnace with the simultaneous introduction of an oxygen-enriched gas into the base of the furnace. The refuse forms a porous packed bed within the vertical shaft which can be analyzed in terms of three functional zones: a drying zone at the top section, a pyrolysis zone in the midsection, and a combustion or melting zone (the hearth) at the base of the furnace. Apparatus useful for practicing the Anderson process is also described in U.S. Pat. Nos. 3,801,082 and 3,985,518 to Anderson.
As the refuse descends through the shaft under the influence of gravity, it is first dried by hot rising gases which are generated in the lower shaft and hearth sections of the furnace. These gases are cooled as they give up their heat to the refuse. As the at least partially dried refuse descends further into the shaft furnace, it is exposed to still higher temperatures resulting in the pyrolysis of the organic content of the refuse. During the pyrolysis phase, the combustible organic material is decomposed in the presence of a hot oxygen-deficient (reducing) atmosphere to a solid char residue and a gaseous mixture consisting predominantly of carbon monoxide, hydrogen and a variety of hydrocarbons. The gaseous mixture rises from the pyrolysis zone while the char and remaining non-volatile inorganic materials descend into the combustion and melting zone or hearth.
In the hearth, the char, which is composed primarily of fixed carbon and ash, is reacted exothermically (combusted) with an oxygen-enriched gas which is fed into the hearth through a plurality of tuyeres. As described in the afore-mentioned Anderson prior art, the tuyeres are radially oriented and are positioned in the lower half of the hearth, just above the slag pool. The heat generated by this exothermic reaction melts any inorganic materials which are present so as to form a molten slag which is continuously tapped or removed from the base of the furnace. The hot gaseous product produced by the exothermic reaction (combustion), consisting primarily of a mixture of carbon oxides, rises into the pyrolysis zone and drives the endothermic reactions occurring therein.
One problem encountered during the initial large scale practice of the Anderson process with shredded refuse was excessive compaction of the vertical refuse bed. Such compaction leads to uneven gas flow through the bed and an attendant decrease in the overall efficiency. It was subsequently discovered that by compacting the refuse into small pellets for feeding into the vertical shaft furnace, many of the problems encountered when operating with shredded refuse could be eliminated. This so-called pelletized refuse process is described and claimed in Anderson U.S. Pat. No. 4,042,345 and significantly improves the overall operation of the basic process.
Even though the pelletized refuse modification of the basic Anderson process has yielded a refuse disposal system that effectively achieves the basic goals of the original process, i.e., the continuous production of a fuel gas and a clean, inert slag residue, one problem still remains. During extended operation of the Anderson pelletized process, it has been observed that some of the char produced within the pyrolysis zone is not sufficiently combusted within the hearth and is entrained in the upwardly flowing gases. This char is accordingly carried out of the vertical shaft furnace with the product gas. While this char entrainment problem does not appear to deleteriously affect the basic function of the process, it does add considerable expense to the system by complicating the fuel gas cleaning apparatus and requiring an additional sub-system for the recycle of the char back into the shaft furnace. Therefore, it would be desirable to reduce or preferably eliminate the problem of char entrainment.
An object of the present invention is to provide a vertical shaft-hearth type furnace for pelletized refuse which reduces the overall level of char entrainment in the gaseous product.
Another object of this invention is to provide a refuse disposal furnace having an improved hearth configuration which provides more complete combustion of the char produced in the pyrolysis zone, thereby contributing to a reduction in char entrainment.
Other objects and advantages of this invention will be apparent from the ensuing disclosure and appended claims.
SUMMARY
This invention relates to apparatus for disposing of pelletized refuse by conversion to useful gaseous product and inert solid residue. The apparatus includes a vertical shaft with an upper end for pelletized refuse introduction which provides a drying zone in the top section and a thermal decomposition zone in the intermediate section thereof to form a pelletized refuse bed. The hearth is beneath the shaft and in flow communication with the lower end of the shaft. Means are provided for feeding oxygen-containing gas into the hearth as a combustion zone. A taphole communicates with the hearth for discharging molten residue therefrom.
More specifically, the improvement comprises:
(a) a hearth volume V (ft 3 ) which is greater than that defined by the following Equation (1):
V=7.28×10.sup.2 G.sub.r D.sub.s.sup.2 /P.sub.g ( 1)
where
G r =pelletized refuse maximum feed rate (lb. refuse/ft 2 shaft minimum cross-sectional area/second),
D s =shaft minimum equivalent diameter (ft), and
P g =minimum furnace pressure (psia).
(b) an opening connection between the shaft and the hearth having minimum cross-sectional area between 0.044 and 1.0 times the shaft minimum cross-sectional area,
(c) a multiplicity of tuyeres as the means for feeding oxygen-containing gas into the hearth, each positioned at circumferentially spaced locations in the upper part of the hearth adjacent to the shaft-hearth connection (b) which are less than 35% of the vertical distance from the shaft-hearth connection (b) mid-point to the hearth floor, with
(d) the tuyeres inclined downwardly and away from the shaft-hearth connection (b) and directed so that the oxygen-containing gas does not impinge directly against the pelletized refuse bed.
As used herein, the term "refuse" includes not only conventional municipal refuse and garbage which commonly contains combustible material such as wood, food waste and non-combustible materials such as metal and glass, but also other materials including but not limited to such materials as coal, sawdust, wood chips and bagasse, which contain a substantial organic and therefore pyrolyzable fraction.
Also with respect to this invention, the expression "pelletized refuse" includes not only refuse which has been compacted into a cylindrical or other shaped block using an apparatus such as that disclosed in Pelton U.S. Pat. No. 4,133,259, but also refuse such as wood which in it raw state may satisfy the pelletation requirements of the aforementioned Anderson U.S. Pat. No. 4,042,345.
As used herein, the term "shaft" refers to a hollow column which may, but need not, have uniform cross-sectional area from end-to-end.
DRAWINGS
FIG. 1 is a vertical cross-sectional view of the lower portion of the vertical shaft and the hearth of a furnace in accordance with one embodiment of this invention, constructed such that the pelletized refuse bed is supported on the shaft lower end.
FIG. 2 is a plan view looking downwardly along line 2--2 of FIG. 1 illustrating in partial cross-section the tuyere location and orientation in the hearth.
FIG. 3 is a graph illustrating the influence of pelletized refuse feed rate and hearth volume on the theoretical mean residence time for gases in the hearth.
FIG. 4 is a vertical cross-sectional view of the lower portion of the shaft and hearth of another embodiment, constructed such that the pelletized bed is supported by the shaft-hearth opening connection.
FIG. 5 is a vertical cross-sectional view of the lower portion of the shaft and hearth of a further embodiment, constructed such that the pelletized refuse bed is supported by the hearth floor, and
FIG. 6 is a plan view looking downwardly along line 5--5 of FIG. 5 illustrating in partial cross-section the tuyere location and orientation in the hearth.
DETAILED DESCRIPTION
Referring to FIG. 1, the furnace 10 consists of a vertical shaft 11 and a hearth 20. The vertical shaft 11 is composed of a metal shell 12 and a refractory lining 13. If desired, the metal shell can be water-cooled in any known manner. It should be understood that the upper end of the vertical shaft 11 (not shown) is provided with means for feeding a pelletized refuse charge into the furnace as well as with means for removing the gaseous products generated within the furnace 10. Suitable apparatus for performing these functions is, for example, disclosed in the aforementioned Anderson U.S. Patents.
The lower end of the vertical shaft 15 is sloped inwardly at 16 to form a restricted hearth opening connection 34. The hearth 20 is supported from and removably connected to the restricted hearth opening connection 34 of the vertical shaft 11 through annular flange 21. This construction is convenient from the standpoint of furnace repair and maintenance. The hearth 20 is also composed of a metal shell 22 and a refractory lining 23. The hearth 20, in particular, is preferably lined with a higher quality refractory than the vertical shaft 11 to conserve heat and withstand the higher temperature prevailing in the hearth. To ensure a long refractory life, the shell of the hearth 20 is also preferably encased in a water-cooled jacket 28. Cooling tends to minimize erosion of the refractory due to the high temperature and severe corrosive conditions prevalent in the hearth. A tapping hole 24 is provided in the base of the hearth 20 for removing slag produced during the operation of the furnace 10. The slag flows out of the hearth through the tapping hole 24 and through the water-cooled slag duct 25. The slag then flows over a slag weir 26 and falls through the slag discharge tube 27 for subsequent quenching.
The hearth 20 is provided with an enlarged volume 30 enclosed by vertical side wall 31 and inwardly inclined dish-shaped ends 32 and 33. The upper dish-shaped end 33 of the hearth 20 is connected to the vertical shaft 11 at the restricted hearth opening connection 34. In the upper part of the hearth volume 30, a plurality of tuyeres 35 are provided. The tuyeres are supplied with an oxygen-containing gas from an appropriate oxygen header (not shown). Preferably, the flow of oxygen-containing gas to each tuyere is separately controllable. As a result, the operator has the option of manipulating and altering the gas flow circulation pattern established by the tuyeres in the hearth. Each tuyere 35 is positioned at circumferentially spaced-apart locations in the upper part of the hearth 20, adjacent to the restricted shaft-hearth opening connection 34.
Preferably, the tuyeres 35 are located at the base 36 of the shaft-hearth restricted opening connection 34. The tuyeres 35 are inclined downwardly at an angle of inclination α away from the restricted hearth opening connection 34. The angle of inclination is preferably in the range of 10 to 45 degrees.
In its broadest aspect, the shaft-hearth opening connection 34 has a minimum cross-sectional area between 0.044 and 1.0 times the shaft 11 minimum cross-sectional area. In the FIG. 1 embodiment, the shaft-hearth opening connection 34 is "restricted" in the sense of being substantially smaller in cross-sectional area than the vertical shaft cross-sectional area, i.e. the aforementioned cross-sectional area ratio is less than 1.0. This relationship, coupled with the inwardly sloped lower end 16 of the vertical shaft joining connection 36, permits the latter to function as a support for the pelletized refuse bed 60.
As compared with a construction in which the pelletized refuse bed is supported on the hearth floor, the FIG. 1 preferred embodiment is more able to prevent the falling of partially pyrolized material into the slag bath. This would exert an undesirable cooling effect on the bath and hearth and thereby possibly result in slag plugging of tapping hole 24. On the other hand, if the aforementioned cross-sectional area ratio is too small, the velocity of the rising gas may be sufficiently high to create unacceptably high char carryover in the gaseous product discharged from the shaft upper end. A restricted opening to shaft cross-sectional area ratio of between 0.075 and 0.2 represents a preferred balance of these considerations for the FIG. 1 embodiment.
A generic requirement for the invention is that tuyeres 35 be oriented so as not to impinge directly against this bed. Since the tuyeres are positioned on the opposite side of shaft-hearth connection 34 and laterally isolated from the pelletized refuse bed 60 by the shaft connection base 36, direct impingement by the oxygen-containing gas is prevented. This construction also prevents the tuyeres from being fouled or plugged by molten slag descending from the pelletized refuse bed 60.
The orientation of tuyeres 35 (and the oxygen-containing gas discharged therefrom) relative to the refuse pellets entering hearth 20 is also illustrated in FIG. 2. In this embodiment of the invention, all of the tuyeres 35 are transversely positioned in an approximately tangential orientation with respect to the shaft-hearth opening connection 34. As used herein an "approximately tangential orientation" means that the angle β formed between the transverse orientation of the axis of the tuyeres 35 (defined by line 42, which is a projection of the extended transverse axis 41 of each tuyere 35 onto the transverse plane of the level of the tuyeres) and a true tangent 43 to a circle 44 inscribed in the hearth at the transverse level of the tuyeres when viewed with respect to the plane of the restricted hearth opening (see FIG. 2) is less than 60 degrees. For example, if the hearth has a circular cross-section at the level of the tuyeres and the tuyeres have a radial orientation, the above angle, β, is 90 degrees. In preferred practice, the angle β is about 25 to 30 degrees.
As shown in FIG. 2, the hearth is provided with eight circumferentially spaced tuyeres 35. In preferred practice, as many tuyeres are provided spaced circumferentially around the hearth as can be physically accommodated in the space available. Each tuyere 35 is directed downwardly and passes through an opening 37 in the upper dish-shaped end 33 of the hearth 20.
As previously indicated, tuyeres 35 must also be positioned at locations in the upper part of the hearth at location(s) which are less than 35% of the vertical distance from the shaft-hearth opening connection 34 middle (in the transverse direction) to the hearth floor. In FIG. 1, horizontal dash line 50 defines the middle of opening 34 in the vertical direction. Horizontal dash line 42 represents the center of the tuyere mouth into the hearth upper part, so that the vertical distance from line 50 to line 42 defines the absolute vertical displacement "d" of the tuyeres into the hearth volume. This displacement "d" divided by the vertical distance "h" from line 50 to the hearth floor 51 multiplied by one hundred is the basis for the previously referenced less than 35% vertical displacement requirement in the FIG. 1 embodiment. As illustrated, the d/h (100) value in FIG. 1 is about 23%.
The tuyeres are positioned within the hearth in the aforedescribed manner for primarily two reasons. Elevation of the tuyeres minimizes the problem of slag plugging which was especially troublesome with the prior art Anderson design disclosed in U.S. Pat. Nos. 3,801,082 and 3,985,518 wherein the tuyeres were positioned in the lower half of the hearth proximate the slag pool. Secondly, and most importantly, the tuyeres are located adjacent to the shaft-hearth connection so as to exert an immediate influence on all combustible materials which pass into the hearth. As will be discussed in more detail hereafter, one of the principal functions of the hearth construction and tuyere orientation combination of this invention is to prolong the retention time of combustible material in the hearth. The long retention time provides more complete char combustion and an attendant decrease in char entrainment. By so positioning the tuyeres, the char descending into the hearth is urged into the circulating gases of the hearth rather than merely relying on gravity to cause char flow into the hearth.
A major advantage to be gained by disposing the tuyeres in a manner indicated in the FIGS. 1 and 2 embodiment is that a cyclonic flow of combustion-supporting gases is created in the upper annular region of the hearth below the hearth opening connection 34. This cyclonic flow of combustion-supporting gases exerts an influence on the entire hearth volume by prolonging the retention time of char particulates which have descended into the hearth. Due to their own inertia in the cyclonic flow pattern, these char particulates tend to remain in the bulk swirling gases instead of flowing with the gaseous products that emanate from the cyclone and flow upwardly through the shaft furnace. As a result, the char is more completely combusted in the hearth and the quantity and size of char particulates which are eventually entrained within the upwardly flowing gases are greatly reduced.
While the approximated tangential orientation of the tuyeres as illustrated in FIG. 2 is preferred, the FIG. 1 embodiment of the invention is also operable with a radial tuyere orientation or any orientation between tangential and radial. The key requirements in this regard are that the tuyere gas discharge not impringe directly against the bed of pelletized refuse supported above the restricted hearth opening 34 and that the tuyere outflows establish an appropriate circulation of gas in the hearth which tends to retain combustible materials in the hearth for extended periods. Direct tuyere gas impingement against the furnace charge, although a standard operating technique for blast furnace operation, is undesirable and avoided in the present invention. Because the apparatus of the present invention is constructed to preferably operate with an enriched-oxygen gas feed for the tuyeres, the flow rate of gas discharging from each tuyere is much smaller than the tuyere outflows in blast furnaces which typically operate with a preheated air feed. As a result, any interference with the tuyere gas discharge flows, such as caused by direct impringement, significantly dissipates and probably eliminates any effective gas circulation established by the tuyeres. Although a tangential tuyere orientation tends to especially benefit the establishment of a highly effective cyclonic gas circulation pattern particularly in combination with the proper angle of inclination, α, of the tuyeres, an appropriate circulation pattern is also developed in the FIG. 1 embodiment if the tuyeres are oriented off the tangent and even if the tuyeres are oriented in a radial plane. For example, the combination of an appropriate angle of inclination α such as 20 degrees and a radial tuyere orientation, β=90 degrees, creates a toroidal gas flow pattern in which the gas flows downwardly in the interior portion of the hearth volume and upwardly near the wall. This flow pattern also tends to prolong the residence time of combustible materials (char) in the hearth. Obviously, a tuyere orientation between these two extremes (i.e., tangential and radial positioning) will create some hybrid of the cyclonic and toroidal gas circulation patterns.
In combination with this aforedescribed tuyere orientation, this invention also requires that the hearth itself have a volume equal to or greater than that defined by Equation (1) as follows:
V=7.28×10.sup.2 G.sub.r D.sub.s.sup.2 /P.sub.g (1)
where
G r =pelletized refuse maximum feed rate (lb. refuse/ft 2 shaft minimum cross-sectional area/second),
D s =shaft minimum equivalent diameter (ft), and
P g =shaft minimum operating pressure (psia).
It should be noted that in Equation (1) G r is the pelletized refuse maximum feed rate, i.e., the maximum rate at which the apparatus may operate for a sustained period of time at maximum efficiency in terms of BTU value in the product gas, percent combustion of the char, minimum char carryover in the product gas, and oxygen utilization. Normally this maximum feed rate is specified in the design criteria for a solid refuse disposal system. It will be apparent from the nature of Equation (1) that if the hearth volume is sized on the basis of this Equation and the system is periodically operated at lower than maximum pelletized refuse feed rate, operation may be continued at a highly efficient level by proportionately reducing the oxygen-containing gas feed rate to the tuyeres.
Equation (1) also specifies G r in terms of the shaft minimum cross-sectional area. This is because the pelletized refuse feed rate is flow limited by the minimum cross-sectional area. Similarly, the shaft width D s is in terms of minimum equivalent diameter, so that a non-circular cross-section is converted to this basis. This dimension is on a "minimum" basis for the same reason G r . The shaft minimum operating pressure P g (psia) refers to the design pressure in the upper section and will be at least slightly above atmospheric. As hereinafter discussed, the pelletized refuse disposal apparatus of this invention is preferably operated by pressure substantially above atmospheric.
The satisfaction of this vertical shaft-dimensional hearth requirement is necessary if complete advantage of all of the benefits to be derived from the previously described tuyere orientation are to be realized. The hearth volume, in connection with the refuse processing rate, controls the rate at which the combustion gas products flow from the body of circulating gas established in the hearth. If the volume is too low, then the expiration rate of the combustion product gases is high and the char retention time in the hearth is disadvantageously reduced causing excessive char entrainment.
The influence of the refuse processing rate (TPD/ft 2 /psia) and the hearth volume (ft 3 ) on the theoretical expiration rate of the combustion product gases from the hearth is illustrated in FIG. 3. The expiration rate of the combustion product gas is not specifically plotted; instead, the mean residence time (θ) of the gas within the hearth is used. However, by definition the mean residence time is inversely related to the gas expiration rate from the hearth (i.e., mean residence time is equal to the hearth gas volume divided by the gas expiration rate). Thus at any specific hearth volume, lower residence times are equivalent to higher expiration rates. Accordingly, high gas retention times are preferred and preferably the hearth is constructed in accordance with this invention so as to provide a theoretical mean gas retention time of at least two seconds. This limitation is reflected in the volume expression of Equation (1).
It should be understood however that the char carryover reduction improvement of this invention is not based solely on increased gas retention time in the hearth. This was demonstrated in a prior art Anderson type pelletized refuse disposal system in which the vertical shaft furnace was a cylinder 82.5 ft 2 cross-sectional area and 26 ft. high. The shaft-hearth opening connection was about 30 ft 2 cross-sectional area and the pelletized refuse/ft 2 shaft minimum cross-sectional area/second was 0.056, ie. G r . The pellets were about 13 inches diameter in lengths of 6-12 inches. The hearth was in the shape of a truncated cone with a 4.8 ft. diameter floor supporting multiple piers having top surface 3 ft. above the floor and positioned such that the transverse distance between opposite piers was 28 inches. The shaft minimum operating pressure was 15 psia (P g ). The eight tuyeres were positioned in the lower part of the shaft 5.5 inches above the hearth floor in accordance with conventional blast furnace practice such that the d distance was 3 ft. and the h distance was 2.5 ft. (reference: FIG. 1). Accordingly, they were 83% of the vertical distance from the shaft-hearth connection middle to the hearth floor. Also, the tuyeres were oriented downwardly so that the α angle was 9 degrees (FIG. 1) and β angle was 90 degrees (FIG. 2).
When operated at the pelletized refuse maximum feed rate of 0.056 lb. refuse/ft 2 shaft minimum cross-sectional area, this prior art Anderson demonstration system discharged excessive char in the overhead gaseous product, i.e., more than about 7% by weight of the refuse feed. It was determined that the theoretical mean gas retention time under these operating conditions was about 0.6 second. In an effort to reduce the char carryover, the pelletized refuse feed rate was reduced to about 0.028 lb. refuse/ft 2 shaft cross-sectional area/second, thereby increasing the theoretical mean gas retention time to about 1.2 seconds. Surprisingly, this did not substantially reduce the char carryover in the gaseous product and the char must be disposed of by means other than discharge to the atmosphere. It is expected that the present invention will permit reduction of the char carryover in the product gas to about 1% by weight of the feed refuse (dry basis).
The advantages provided by the present invention are most effectively utilized when the furnace is operated at an elevated pressure, as will be demonstrated by reference to FIG. 3. As discussed earlier, the principal function of the hearth is to provide a proper environment for combustion of the char produced during pyrolysis of the refuse, whereby sufficient heat is generated to melt the inorganic fraction of the refuse and drive the endothermic pyrolytic reactions occurring in the vertical shaft of the furnace. The present invention is able to efficiently provide these functions as a result of the improved hearth geometry and tuyere orientation.
According to FIG. 3, if the hearth is provided with a volume of 100 ft 3 , a refuse feed rate of 0.088 TPD/ft 2 /psia will result in a mean gas residence time of about 2 second. At an operating pressure of 15 psia, this performance corresponds to a specific throughput of 1.32 TPD/ft 2 whereas at an operating pressure of 65 psia, this performance corresponds to a specific throughput of 5.72 TPD/ft 2 . The higher pressure operation provides a 333% increase in throughput corresponding directly to the pressure increase. The value of pressurization, however, can be most effectively utilized in a different manner. Instead of designing the pressurized hearth with the same volume as the 15 psia design, one can reduce the hearth volume. Although this design change will dictate a decrease in the specific throughput, it will have the advantageous effect of reducing the surface area and accordingly, the heat leak of the hearth. The lower heat leak permits higher temperature operation and significantly improves the conditions for both the combustion and melting functions of the hearth. For instance, if in the previous example the hearth volume is reduced to 80 ft 3 , the surface area of the hearth is reduced by 18%. Nonetheless, the specific throughput is still over 260% higher than in the 15 psia design.
Referring next to FIG. 4, another embodiment of the invention will be described. For comparison purposes, elements corresponding to those in FIG. 1 are assigned the same identification numeral plus 100. FIG. 4 differs from FIG. 1 with respect to the design of the restricted hearth opening connection 134, which separates the vertical shaft 111 from the hearth 120. Hearth opening connection 134 is in the form of an annular ring 161 of refractory material with the upper surface functioning as the inwardly sloped, lower portion of the vertical shaft. This annular ring 161 is contiguous with the refractory lining 123 of the hearth.
In the operation of furnace 110, the pelletized refuse charge is fed to the top of the vertical shaft 111 by means not shown. As the pelletized refuse descends through the shaft, it is successively dried and pyrolyzed by the hot gases issuing from the hearth 120. The still pelletized refuse bed 160 is supported above the hearth 120 by the annular ring 161. The latter provides the necessary bridging action to prevent unpyrolyzed material from falling into the hearth, while allowing the char residue to descend into the hearth for subsequent combustion. The heat generated by char combustion also serves to melt the inorganic fraction in the refuse bed 160 which falls to the hearth floor 151 and forms a slag pool. The molten slag is continuously tapped from the hearth through the tapping hole 124. The slag flows through the slag duct 125 over the slag weir 126 and falls through the slag discharge tube 127 for subsequent quenching.
By way of illustration, a furnace designed according to the FIG. 1 embodiment of this invention for processing 200 tons per day of 10 inch diameter and 6-12 inches long pelletized refuse may typically have a 22 ft. vertical cylindrical shaft with an inside diameter of about 8.25 ft. On this basis the G r value is 0.088 lb. refuse/ft 2 shaft cross-sectional area/second. The lower portion of the vertical shaft can be sloped inwardly at about a 25 degree angle so as to define a restricted hearth opening connection with a diameter of about 2.65 ft. The restricted opening may have a cylindrical shape with a height to diameter ratio of about 0.4. The base of the restricted hearth opening is flared outwardly into an enlarged hearth volume. The hearth is cylindrical in shape having a diameter of about 5.5 ft. and an enclosed volume of about 82 cu. ft. The hearth is operated at pressure of at least 57 psia (Pg). The hearth is provided with sixteen circumferentially spaced tuyeres. The tuyeres are located in the upper portion of the hearth adjacent to the restricted shaft-hearth opening connection at a plane d which is located approximately 23% of the vertical distance h through the hearth volume as measured from the midpoint of the restricted opening to the floor of the hearth. The tuyeres are inclined downwardly into the hearth volume in an approximately tangential orientation with respect to the restricted hearth opening connection. The tuyeres are inclined downwardly into the hearth volume at an angle α of 20 degrees.
FIG. 5 illustrates another embodiment of the invention, in which the shaft-hearth opening connection 234 is not of smaller cross-sectional area than shaft 211, but is simply the same size as the shaft lower end. The hearth 220 is provided with an enlarged annular volume 230 enclosed by vertical side wall 231, inwardly inclined dish-shaped ends 232 and 233 and the conically-shaped refuse bed 260. The latter is supported by the hearth floor 251, in contrast to the embodiments of FIGS. 1 and 4. An advantage of this construction is that the velocity of the rising gas (with char charryover) is not increased by flow through a restricted opening. A disadvantage is that portions of the pelletized bed 260 may break off and fall into the slag. If the practioner wishes to form the pelletized refuse bed on the hearth floor as illustrated in FIG. 5, the shaft opening connection minimum cross-sectional area is preferably between 0.7 and 1.0 times the shaft minimum cross-sectional area.
The upper dish-shaped end 233 of the hearth 220 is connected to vertical shaft 211 at the restricted hearth opening connection 234. In the upper region of the hearth volume 230, a plurality of tuyeres 235 are provided. The tuyeres are supplied with an oxygen-enriched gas from an appropriate oxygen header (not shown). Each tuyere 235 is positioned at circumferentially spaced-apart locations in the upper region of the hearth 220, adjacent to the opening connection 234. Tuyeres 235 are located in the upper end 236 of hearth 220, and inclined downwardly at an angle away from the opening connection 234. The angle of α inclination is preferably in the range of 10 to 45 degrees.
All of the tuyeres 235 are positioned in an approximately tangential orientation with respect to connection 234, as illustrated in FIG. 6. As shown, the hearth is provided with eight circumferentially spaced tuyeres 235. Each tuyere 235 is directed downwardly and passes through an appropriately constructed opening 237 in the upper dish-shaped end 233 of the hearth 220. It should also be noted with respect to FIG. 5, that the tuyeres are positioned so as not to be fouled or plugged by any molten slag descending from the refuse column 260 supported or the hearth floor 252. The angle β in this embodiment is about 20 degrees.
Also as discussed earlier, this invention also requires that the hearth itself have a volume equal to or greater than that defined by Equation (1). In the FIGS. 5-6 embodiment, the hearth volume comprises the annular space bounded by the vertical side wall 231, the upper and lower dish-shaped ends, 233 and 232 respectively and the central, conically-shaped column of pelletized material illustrated by dash line 260, reduced by the volume occupied by the refractory material coating the inner wall of the hearth 220. This volume may be approximated by the Equation (2) ##EQU1## where
h=the vertical distance from the shaft-hearth opening connection 234 (horizontal line 250) to the hearth floor 252,
D H =the internal diameter of the hearth,
D S =the shaft diameter (the diameter of the opening connection 234), and
D B =the width of the column of pelletized material resting on the hearth floor 252.
Formula (2) assumes that the supported refuse bed 260 assumes a truncated conical shape. One of ordinary skill will understand how to compute the hearth volume if the column assumes a different shape.
Although preferred embodiments of the invention have been described in detail, it will be appreciated that other embodiments are contemplated along with modifications of the disclosed features as being within the scope of the invention. | 4y
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[0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/520,182, filed Nov. 14, 2003.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention is directed to a method of contraception that provides for the reduction or elimination of estrogen in the initial phase of a multiphasic estrogenic/progestogenic contraceptive regimen without compromising contraceptive efficacy or cycle control. The invention is also directed to a multiphase contraceptive kit that may be used to practice the method of the invention.
[0004] 2. Related Background Art
[0005] Contraceptive compositions containing both estrogenic and progestogenic compounds are well known. The progestogenic component of the composition is primarily responsible for the contraceptive efficacy of the composition, while the estrogenic component is employed to reduce undesired side effects, such as breakthrough bleeding or spotting.
[0006] The earliest of these estrogenic/progestogenic contraceptive compositions contained a relatively high level of estrogenic component. A constant goal, however, has been to reduce the estrogenic potency of such compositions without reducing contraceptive efficacy and increasing undesired side effects. As described in U.S. Pat. No. 5,888,543, in an attempt to achieve this goal, numerous regimens have been developed in which the progestin/estrogen combination is administered in a monophasic regimen (fixed dose) or as biphasic or triphasic regimens (varied dose).
[0007] A particularly advantageous technique for reducing total estrogenic administration is described in U.S. Pat. No. 4,962,098. This describes a triphasic method of contraception using a progestogen/estrogen combination in which the amount of estrogen is increased stepwise over the three phases. The first phase is 4-7 days, the second phase is 5-8 days and the third phase is 7-12 days. Preferably, the administration of the contraceptive compositions for the three phases will be 21 days followed by a 7 day placebo period. For all three phases the progesten is 0.5 to 1.5 mg of norethindrone acetate, while about 10 to 30 mcg of ethinyl estradiol is used in the first phase, about 20 to 40 mcg of ethinyl estradiol is used in the second phase and 30 to 50 mcg of ethinyl estradiol is employed in the third phase.
[0008] There is a continuing desire, however, to further reduce the amount of estrogenic component in an estrogenic/progestogenic composition with continued contraceptive efficacy while avoiding undesired side effects. Heretofore it was believed that at least 10 mcg of ethinyl estradiol or its estrogenic equivalent was needed in an estrogenic/progestogenic composition to assure contraceptive efficacy. It has now been surprisingly discovered that the amount of estrogenic component in the first phase of a triphasic regimen can be significantly reduced or eliminated without compromising efficacy or cycle control.
SUMMARY OF THE INVENTION
[0009] This invention is directed to a multiphasic method of contraception that provides for the reduction or elimination of administered ethinyl estradiol in the first phase without a reduction in contraceptive efficacy or an increase in undesired side effects. The method of this invention includes administering, in sequential steps, to a female of child bearing age the following compositions: (a) composition I for about 5 to about 9 days; (b) composition II for about 5 to about 9 days; and (c) composition III for about 8 to about 12 days. Compositions I, II and III all contain a progestogen in an amount equivalent to about 0.3 to about 1.5 mg, preferably about 0.5 to about 1.5 mg of norethindrone acetate. Composition I contains an estrogen in an amount equivalent to about 0 to less than about 10 mcg of ethinyl estradiol and both compositions II and III contain an estrogen in an amount equivalent to about 10 to about 50 mcg of ethinyl estradiol.
[0010] Significantly, the sequential administration of compositions I, II and III is repeated after a period of about 1 to about 4 days has elapsed after completion of the administration of composition III. Without being bound by theory, it is believed that this relatively short interim period between the sequential administration of the estrogenic/progestogenic components allows for the advantageous reduction or elimination of estrogen from the first phase of the above-described triphasic regimen without compromising efficacy or cycle control. It is also preferable that the amount of estrogen be increased by at least an amount equivalent to 5 mcg of ethinyl estradiol between composition II and composition III. In a preferred embodiment of this invention, the estrogen is ethinyl estradiol and the progestogen is norethindrone acetate.
[0011] Yet another embodiment of this invention is directed to a multiphase combination and contraceptive kit comprising a package containing daily dosages of: (a) a Phase I composition containing a progestogen in an amount equivalent to about 0.3 to about 1.5 mg, preferably about 0.5 to about 1.5 mg of norethindrone acetate and an estrogen in an amount equivalent to about 0 to about 10 mcg of ethinyl estradiol; (b) a Phase II composition containing a progestogen in an amount equivalent to about 0.3 to about 1.5 mg, preferably about 0.5 to about 1.5 mg of norethindrone acetate and an estrogen in an amount equivalent to about 10 to about 50 mcg of ethinyl estradiol; and (c) a Phase III composition containing a progestogen in an amount equivalent to about 0.3 to about 1.5 mg, preferably about 0.5 to about 1.5 mg of norethindrone acetate and an estrogen in an amount equivalent to about 10 to about 50 mcg of ethinyl estradiol; wherein the amount of estrogen in the Phase III composition is at least an amount equivalent to 5 mcg of ethinyl estradiol greater than the amount of estrogen in the Phase II composition. Preferably, the estrogen used in the kit is ethinyl estradiol and the progestogen is norethindrone acetate.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The method of this invention is practiced by administration of the compositions in a numeric sequence with the Phase I composition being used first, the Phase II composition being used second, etc. If packaging and/or other requirements dictate, the method and kit described herein can be employed as part of a larger scheme for contraception or treatment of gynecological disorders. While the sequence in which Applicant's combinations are administered is important to their operation, it should be kept in mind that variations in timing and dosage can be tolerated when medical considerations so dictate.
[0013] Significantly, the method of this invention provides that the sequential administration of compositions I, II and III is repeated after a period of about 1 to about 4 days has elapsed after the completion of the administration of composition III. More preferably, the number of days between the completion of the administration of composition III and beginning the repeated sequential administration of compositions I, II and III is from about 2 to about 4 days. During this interim period an iron supplement and/or a placebo may be preferably administered on a daily basis, although there is no requirement for the administration of anything during this interim period, i.e., the period between the completion of the prior sequential administration of compositions I-III and the start of the next sequential administration of compositions I-III.
[0014] Estrogens which may be used in the present invention include, for example, ethinyl estradiol, 17β-estradiol, 17β-estradiol-3-acetate, mestranol, conjugated estrogens, USP and estrone or salts thereof. The amount of estrogen used is described herein as that which is “equivalent” in estrogenic potency to an amount of ethinyl estradiol. The equivalent estrogenic potency of an estrogen to ethinyl estradiol may be readily determined by one of ordinary skill in the art. It is contemplated that each Phase could employ one or more different estrogens that deliver a potency equivalent to the recited amount of ethinyl estradiol. It is also contemplated that the estrogen used in one Phase may be different than that used in another Phase. In a most preferred embodiment of this invention, however, the estrogen for each Phase, if present, is ethinyl estradiol.
[0015] Progestogens which may be used in the present invention include, for example, progesterone and its derivatives such as 17-hydroxy progesterone esters and 19-nor-17-hydroxy progesterone esters, 17-alpha-ethinyl testosterone, 17-alpha-ethinyl-19-nortestosterone (norethindrone) and derivatives thereof, norethindrone acetate, norgestrel, nogestamate, desogestrel and D-17-beta-acetoxy-17-beta-ethyl-17-alpha-ethinyl-gon-4-en-3-one oxime. Other exemplary progestogens include demegestone, drospirenone, dydrogesterone, gestodene, medrogestone, medroxy progesterone and esters thereof. The amount of progestogen used is described herein as that which is “equivalent” in progestogenic potency to an amount of norethindrone acetate. The equivalent progestogenic potency of a progestogen to norethindrone acetate may be readily determined by one of ordinary skill in the art. It is contemplated that each Phase could employ one or more different progestogens that deliver a potency equivalent to the recited amount of norethindrone acetate. It is also contemplated that the progestogen used in one Phase may be different than that used in another Phase. In a most preferred embodiment of this invention, however, the progestogen for each Phase is norethindrone acetate.
[0016] Accordingly, in a preferred embodiment of this invention the compositions employed in accordance with the invention will contain in Phase I about 0.3-1.5 mg, preferably about 0.5-1.5 mg norethindrone acetate and about 0 to less than about 10 mcg ethinyl estradiol, preferably about 0 to about 5 mcg ethinyl estradiol, in Phase II about 0.3-1.5 mg, preferably about 0.5-1.5 mg norethindrone acetate and about 10-50 mcg ethinyl estradiol, preferably about 20-40 mcg ethinyl estradiol, and in Phase III about 0.3-1.5 mg, preferably about 0.5-1.5 mg norethindrone acetate and about 10-50 mcg ethinyl estradiol, preferably about 25-50 mcg ethinyl estradiol, wherein the amount of ethinyl estradiol is increased by at least 5 mcg from Phase II to Phase III
[0017] A significant aspect of the method and kit of this invention is that the Phase I composition has a significantly lower concentration of estrogen equivalent to ethinyl estradiol than previously considered possible, while maintaining contraceptive efficacy and avoiding or minimizing unwanted side effects such as break through bleeding. In one particularly preferred embodiment the amount of estrogen equivalent to ethinyl estradiol in the Phase I composition is about 5 mcg. In another particularly preferred embodiment the Phase I composition is substantially free of estrogen, and most preferably is substantially free of ethinyl estradiol. As used herein “substantially free” means that estrogen is not detectable or only pharmacologically insignificant minor levels are present.
[0018] An optional Phase IV composition, which contains an iron supplement, e.g., ferrous fumarate, and/or one or more placebos, can be used in conjunction with the other three.
[0019] The particularly preferred compositions employed in accordance with the invention in Phases I through IV will more preferably have the administration times and drug contents set forth in the following tables when a four-phase system is used. Each table sets forth relevant values for one of Applicant's preferred embodiments, or configurations, for administration of the system to females.
[0000]
TABLE 1
mg Norethindrone
Phase
Days
acetate
mcg EE
mg Fumarate
I
7
1.0
5
0
II
7
1.0
30
0
III
10
1.0
35
0
IV
4
—
—
75
[0000]
TABLE 2
mg Norethindrone
Phase
Days
acetate
mcg EE
mg Fumarate
I
7
1.0
0
0
II
7
1.0
30
0
III
10
1.0
35
0
IV
4
—
—
75
[0020] The norethindrone acetate (NA) and ethinyl estradiol (EE) are well known and readily available. Clearly, the amount of NA and EE may be varied in accordance with the disclosure of this invention. For example, the amount of NA set forth in Tables 1 and 2 could readily be adjusted from 1 mg to 0.5 mg or 0.4 mg.
[0021] The designation “mcg” refers to micrograms and “mg” to milligrams.
[0022] It should be noted that these tables are presented for illustrative purposes only. The substitution of functionally equivalent amounts and kinds of reagent(s) in these schemes is contemplated. For example, the use of sugar or other placebo in place of all or part of the ferrous fumarate is envisioned.
[0023] The compositions used in this invention are administered using a suitable daily dosage form. Tablets, pills, capsules and caplets are exemplary dosage forms.
[0024] In addition, the use of other conventional additives, e.g., fillers, colorants, polymeric binders, and the like is also contemplated. In general any pharmaceutically-acceptable additive which does not interfere with the function of the active components can be used in one or more of the compositions.
[0025] Suitable carriers with which the compositions can be administered include lactose, starch, cellulose derivatives and the like used in suitable amounts. Lactose is a preferred carrier. Mixtures of carriers, e.g. lactose, microcrystalline cellulose and starch, are operable.
[0026] While the norethindrone acetate is preferred, as previously noted it may be replaced by a different progestogen. Similarly, while the ethinyl estradiol component is preferred it may be completely or partially replaced with one or more conventional estrogenic substances, e.g., mestranol.
[0027] While the invention is discussed as potentially one employing four phases, it clearly may employ only three. Phase IV is not essential to the operation of the other three distinct phases. Thus a method or kit which does not contain the Phase IV component is operable and, in fact, will be preferred when suitable factors, e.g., economy, dictate the non-use of the Phase IV component. As previously noted, whether a Phase IV component is used or not, it is preferably that the period between the completion of the Phase III composition and the start of the Phase I composition in the subsequent sequence not exceed about 4 days.
[0028] The terms “method” and “kit” are used herein to encompass any drug delivery systems via the use of which the 3- or 4-phase scheme outlined above can be effectively administered to human females. Combinations of various dosage forms are operable.
[0029] A unique dosage pattern, i.e., a unique sequence of administration of a novel estrogen/progestogen combination has been discovered which minimizes the administration of estrogen in the first phase of a multiphase regimen, while also minimizing certain side effects, notably breakthrough bleeding, commonly associated with conventional low dosage pills.
[0030] Reasonable variations, such as those which would occur to a skilled artisan, can be made herein without departing from the scope of the invention. | 4y
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an inner mold terminal of a wire clamping machine, more particularly to a terminal structure used in a terminal wire clamping machine with an auto aligning feeder; such auto aligning feeder is used to arrange and align the disordered terminal inner molds automatically and feed them into a terminal wire clamper for the automatic terminal wire clamping operation.
2. Description of the Related Art
The method of manufacturing electric wire connectors regardless of the two-pin or three pin ones includes the steps of fixing the electric wire with the metallic insert pin of the connector, and then putting them into a mold for filling and fixing with plastic materials in order to wrap and fix the electric wire and the metal insert pin. However, such method usually causes defects to the finished goods and gives a high failure rate due to the wrong positioning of the wire and metallic insert pin by the operator. Therefore, manufacturers have developed an inner mold terminal as shown in FIG. 1 , and such terminal inner mode has a through hole with appropriate size and position, so that the operator can connect the connecting end of the electric wire and the metallic insert pin first before inserting and fixing the metallic insert pin to the terminal inner mold. By such terminal inner mold, the metallic insert pin and the electric wire can be correctly positioned when the electric wire connector is molded, and such arrangement no longer causes defects to the finished goods due to the crooked positioning of pins.
However, the manufacturing procedure of such method by manually fixing the electric wire with the metallic insert pin and then manually inserting the metallic insert pin into the through hole of the inner mold terminal totally relies on the manual operations, and requires the clipping actions for three times to complete the connection of a set of metallic insert pin and the electric wire. Such clipping action cannot be completed in one time, not only wasting time, but also requiring a great deal of manpower, which causes limitations to the production output and makes the mass production difficult or even impossible.
SUMMARY OF THE INVENTION
The primary objective of the present invention is to provide a way of automatically completing the action of arranging the terminal inner molds in order, feeding, punching, and clamping automatically, not only can connect the whole set of metallic insert pins with the electric wire, but also can use the automated machine to replace labor forces and reduce costs.
To achieve the above objectives, the technical measure taken according to this invention comprises:
a terminal wire clamper having a feeding groove, and the feeding groove at its rear end having a feeding push rod and at its front end having a terminal mold plate module that further comprising an upper mold plate and a lower mold plate, and the upper mold plate being disposed at the corresponding position above the lower mold and coupling to a pressurized motion device; an aligning conveyer comprising an aligning groove for accommodating and storing the terminal inner groove, an opening at one end of the aligning conveyer being coupled to the side of the feeding groove; and a vibratory conveying motor disposed under the aligning feeder; an auto aligning feeder having a vibratory disc on a machine table, and such vibratory disc having a spiral track that includes a positive and inverse alignment area, an angle alignment area, and an open position alignment area; wherein the spiral track is coupled to an opening at another end of the aligning groove; a plurality of terminal inner molds, each having a ground terminal and two connecting terminals aligned in order and disposed on an inner mold stand, wherein the connecting terminal at its end having an outwardly bent wire clamping section such that the center of the wire clamping section shifting towards the outer side of the inner mold.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, in which:
FIG. 1 is an illustrative diagram of the assembled inner mold terminal according to the prior art.
FIG. 2 is a perspective diagram of the present invention.
FIG. 3 is a perspective diagram of the inner mold terminal to according to the present invention.
FIG. 4A is an illustrative diagram of the motion of the terminal wire clamper according to the present invention.
FIG. 4B is another illustrative diagram of the motion of the terminal wire clamper according to the present invention.
FIG. 4C is another further illustrative diagram of the motion of the terminal wire clamper according to the present invention.
FIG. 5 is a perspective diagram of the finished goods of the inner mold terminal according to the present invention.
FIG. 6 is an illustrative diagram of the planar motion of the auto aligning feeder according to the present invention.
FIG. 7A is a cross-sectional diagram of the line 7 A— 7 A as depicted in FIG. 6 .
FIG. 7B is a cross-sectional diagram of the line 7 B— 7 B as depicted in FIG. 6 .
FIG. 7C is a cross-sectional diagram of the line 7 C— 7 C as depicted in FIG. 6 .
FIG. 7D is a cross-sectional diagram of the line 7 D— 7 D as depicted in FIG. 6 .
FIG. 8 is an illustrative diagram of the planar motion of the auto aligning feeder according to a second preferred embodiment of the present invention.
FIG. 9A is a perspective diagram of the inner mold terminal according to a second preferred embodiment of the present invention.
FIG. 9B is a perspective diagram of the finished goods of the inner mold terminal according to a second preferred embodiment of the present invention.
FIG. 10A is a cross-sectional diagram of the line 9 A— 9 A as depicted in FIG. 8 .
FIG. 10B is a cross-sectional diagram of the line 9 B— 9 B as depicted in FIG. 8 .
FIG. 10C is a cross-sectional diagram of the line 9 C— 9 C as depicted in FIG. 8 .
FIG. 10D is a cross-sectional diagram of the line 9 D— 9 D as depicted in FIG. 8 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An auto-feed terminal wire clamping machine and its terminal structure comprises:
A plurality of inner molds 40 as shown in FIG. 3 being an inner mold stand substantially triangular in shape, having two sheet connecting terminals 411 , 412 disposed thereon, and the connecting terminal 411 , 412 at the end having a wire connecting section 421 , 422 , wherein the wire connecting section 421 , 422 being bent outward to form a bottom edge 431 , 432 , and the outer side of the bottom edge 431 , 432 being bent into an external sidewall 441 , 442 with a right angle, and the inner edge of the bottom edge 431 , 432 being bent downward to form an internal sidewall 451 , 452 , wherein the external sidewall 441 , 442 and the internal sidewall 451 , 452 being equal in length; a cylindrical connecting terminal 413 and the rear end of the connecting terminal 413 being bent and folded to form a clamping end with an opening upward;
A terminal wire clamper 10 , as shown in FIG. 2 , comprising a feeding groove 11 disposed on a motive force machine table, and the rear end of the feeding groove 11 having an feeder 12 driven by an oil-pressure cylinder or air-pressure cylinder, and the front end of the feeder 12 being coupled to a feeding push rod 121 and sliding within the feeding groove 11 ; a feeding sensing device 111 disposed on the internal sidewall of the feeding groove 11 for detecting if there is an inner mold terminal 40 in the feeding groove 11 ; further the feeding groove 11 at its front end having a terminal mold plate module 13 which comprises an upper mold plate 131 and a lower mold plate 132 of corresponding shapes; wherein a pressurized motion device 14 disposed above the motive force machine table, and the upper mold plate 131 being secured to the bottom end of said pressurized motion device 14 , and the lower mold plate 132 being secured to the front end of the feeding groove 12 , and vertically corresponsive to the position directly under the upper mold plate 131 so that the pressurized motion device 14 producing a vertically down movement by the driving motive force, and brining the upper mold plate 131 to punch downward and engaging with the lower mold plate 132 ;
An aligning conveyer 20 , having an aligning groove 21 , and the aligning groove 21 being a storage space for accommodating and storing the inner mold terminal 40 , and an opening at one end of the aligning groove 21 being coupled to an edge of the feeding groove 11 , and a vibratory conveying motor 22 being disposed under the aligning conveyer 20 ; by means of the vibration produced by the vibratory conveying motor, the terminal inner molds 40 in the aligning groove 21 being pushed forward into the feeding groove 11 ; wherein a motion detector 211 being disposed on the sidewall of the aligning groove 21 ;
An auto aligning feeder 30 , having a vibratory disc 32 on a machine table 31 for placing a plurality of terminal inner molds 40 , and the vibratory disc 32 having an inwardly aslant spiral track 33 , and the spiral track have a clockwise and counterclockwise aligning area 34 , an angle aligning area, 35 and an open positioning area 36 ; a fixed direction arc plate 341 being secured on the clockwise and counterclockwise aligning area 34 on the spiral track 33 to define a clipping space 342 ; a stirring rod 361 in the same direction and a latch stirring rod 362 being disposed at the open positioning area 36 ; a latch flange 363 being disposed on and protruded from the spiral track 33 ; wherein the spiral track 33 being coupled to the opening at another end of the aligning groove 21 , and an opening disposed near the external edge of each aligning area for receiving the eliminated terminal inner molds 40 that falls into the lower layer of the spiral track 33 for sieving again; users may pour large quantity of terminal inner molds into the vibratory disc 32 ; by the vibration of the vibratory disc 32 , the terminal inner molds 40 gradually spreading out and moving up along the spiral track 33 .
Please refer to FIGS. 4A to 4 C. When the aligning conveyer 20 pushes and conveys the terminal inner molds 40 in the aligning groove 21 into the feeding groove 11 , the feeding sensor 111 will immediately start feeding device 12 . The feeding push rod 121 is used to push the terminal inner molds 40 in the feeding groove 11 to the lower mold plate 132 , and attach the wire connecting section 421 , 422 and the clamping end 423 of the inner mold terminal 40 closely to the lower mold plate 132 (as shown in FIG. 4 B). Then, the operator can put the end of an electric wire 50 directly in each wire connecting section 421 , 422 and the clamping end 423 or in the recession on the upper mold plate 131 . Then, the pressurized motion device 14 is started to drive the upper mold plate 131 and the electric wire 50 to press down. When the upper mold plate 131 and the lower mold plate 132 are engaged and pressed tightly, the wire connecting section 421 , 422 , clamping end 423 , and electric wire 50 are pressed simultaneously for the connection (as shown in FIG. 4 C). When the upper mold plate 131 returns to its original position, the finished goods (as shown in FIG. 5 ) can be taken out, and returns the feeding push rod 121 to the original position for repeating the previous motions; further, when the terminal inner molds 40 in the aligning conveyer 20 is reduced to a certain level (less than the predetermined safety storage), the motion detector 211 will drive the auto aligning feeder 30 to start operating and sieve and convey the inner mold terminal 40 from the vibratory disc 32 into the aligning conveyer 20 . If the storage of the terminal inner molds 40 in the aligning conveyer is full, the power of the auto aligning feeder 30 will be disconnected automatically in order to control the quantity of terminal inner molds 40 for the manufacturing, and save the power consumption.
Please refer to FIG. 6 . The theory for the auto aligning feeder 30 to adjust and align the terminal inner molds 40 is described in detail as follows:
When the inner mold terminal 40 enters into the clockwise and counterclockwise aligning area 34 , the fixed direction arc plate 341 in a clipping space 342 can fix the connecting terminal 411 , 412 and the ground terminal 413 of the inner mold terminal 40 in the positive direction; on the contrary, since the direction is opposite or other disorderly compiled terminal inner molds 40 cannot be fixed in the clipping space 342 , the terminal inner molds 40 will fall down from the open groove 37 . Further, as shown in FIG. 7A , when the inner mold terminal 40 enters into the angle aligning area 35 , the flange of the inner mold terminal 40 will latch to the edge of the spiral track 34 ; if there is a deviation to the angle of the inner mold terminal (as shown in FIG. 7 B), the flange of the inner mold terminal 40 is unable to latch to the edge of the spiral track 34 . When the vibratory disc 33 vibrates, the deviated inner mold terminal 40 will slide down along the slope of the spiral track 34 into next layer of the spiral track 34 for another sieve.
When the inner mold terminal 40 enters into the open positioning area 36 , the stirring rod 361 in the same direction can adjust the position of each inner mold terminal 40 such that the inner side of the inner mold terminal 40 aligned with the stirring rod 361 in the same direction. Please refer to FIG. 7 C. Since the connecting terminal 411 , 412 of the inner mold terminal 40 is shorter than the ground terminal 413 , when the metallic insert pin of the connecting terminal 411 , 412 presses against the latch flange 363 , the ground terminal 413 protrudes from the top of the latch flange 363 so that the inner mold terminal 40 can exactly pass through the latch stirring rod 362 . If the inner mold terminal 40 rotates in an improper direction, the ground terminal 413 will press against the latch flange 363 and cause the inner mold terminal to protrude from the latch stirring rod 362 and fall into the open groove 37 .
By means of the action of the foregoing aligning area in a clockwise and counterclockwise aligning area 34 , angle aligning area 35 , and open positioning area 36 , the sieved inner mold terminal can be arranged neatly and sent into the feeding groove 11 of the terminal clamping device 10 in a fixed direction, so that the terminal clamping device 10 will automatically complete the clamping of the terminal.
Please refer to FIGS. 8 to 10 for the second preferred embodiment of the present invention, which can also be applied in the 2-pin terminal without a grounding terminal. Except the sieving method of the auto aligning feeder 30 is different and it requires to change to the terminal plate module 13 of the corresponding shape, the rest is the same as that described above, and thus will not be described here.
In FIG. 9 , a plurality of inner mold terminals 70 , each being an inner mold stand in the shape of rectangular blocks and having two plate connecting terminals 711 , 712 , and a wire connecting section 721 , 722 at the end of the inner mold terminal 70 . The outer sides of the wire connecting section 721 , 722 are bent and folded into a bottom edge 731 , 732 , and the outer end of such bottom edge 731 , 732 is bent upward into a right angle to form an outer sidewall 741 , 742 , and the inner edge of the bottom edge 731 , 732 is bent downward and then upward to form an inner sidewall 751 , 752 , wherein the outer sidewall 741 , 742 and the inner sidewall 751 , 752 are equal in height; and the wire connecting section 721 , 722 is for passing and fixing one end of an electric wire 80 .
In FIG. 8 , the auto aligning feeder 60 has a vibratory disc 62 ; the vibratory disc 62 has a spiral track 63 ; the spiral track has a clockwise and counterclockwise aligning area 64 and an open positioning aligning area 65 ; such clockwise and counterclockwise aligning area 64 has a fixed direction arc plate 641 secured on the spiral track 63 to define a clipping space; the fixed direction arc plate 641 has a fixed stirring rod 642 , and such fixed direction stirring rod 642 has a height slightly higher than that of the lying inner mold terminal 70 ; such open positioning aligning area 65 has a latch stirring rod 651 ; wherein the side of the vibratory disc 62 adjacent to each aligning area has an open groove 66 for eliminating some inner mold terminals 40 and allowing them to fall to the next layer of the spiral track 63 for sieving again.
When the inner mold terminal 70 enters into the clockwise and counterclockwise aligning area 64 , the clipping space of the fixed direction arc plate 641 can fix the connecting terminal 711 , 712 of the inner mold terminal 70 in the positive direction. On the contrary, since the connecting terminal 711 , 712 of the inner mold terminal 70 in the reverse direction or disorderly piled cannot be fixed in the clipping space, and will fall off from the open groove 66 . Further, in FIG. 10A , the fixed stirring rod 642 has a height slightly higher than that of the lying inner mold terminal 70 , therefore, the inner mold terminals 70 can pass through the fixed stirring rod 642 , but the vertical inner mold terminal 70 as shown in FIG. 10B has a height higher than that of the fixed stirring rod 642 , therefore the inner mold terminals 70 will be stirred out by the fixed stirring rod when they pass through the fixed stirring rod 642 .
Further, please refer to FIG. 10 C. Since the clipping end 712 of the inner mold terminal 70 is biased, and when the opening of the wire connecting section 721 , 722 faces upward, the height of the clipping end 712 can pass through the latch stirring rod 6651 . When the opening of the wire connecting section 721 , 722 faces downward and the inner mold terminal 70 tries to pass through the latch stirring rod 651 , the inner mold terminal will be stirred out by the latch stirring rod 651 .
By the motion described above, the present invention not only can be applied to the inner mold terminal 40 with 3 pins, but also can be applied to the inner mold terminal 70 with two pins. Further, the present invention can be applied to the inner mold stands of other different kinds of connectors by adjusting the aligning device.
While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that the invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation and equivalent arrangements. | 4y
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This Application claims priority under 35 U.S.C. 119(e) to provisional applications U.S. Ser. No. 60/877,783 filed Dec. 29, 2006 and U.S. Ser. No. 60/978,676 filed on Oct. 9, 2007 both of which are incorporated by reference herein.
FIELD OF THE INVENTION
The invention relates to a beverage container holder for vehicles and more particularly, to a beverage holder which removably mounts to a support platform.
BACKGROUND OF THE INVENTION
Cupholders in various types of boats such as power boats and vehicles such as recreational vehicles are known. Often, the boat or vehicle is not provided with the optimum number or location for the cupholders and it is desirable to retrofit the vehicle or boat with a cupholder. Cupholders may be adapted for mounting to existing vehicle platforms which may include any type of structural mounting locations on a vehicle. Such structural mounting locations may include but are not limited to the armrests of seats which may serve as a mounting platform for such drink holders.
SUMMARY OF THE INVENTION
The invention relates to an improved beverage container holder which is readily mountable to the support platform on a boat, vehicle, or the like. The beverage container holder comprises a cylindrical can which is adapted to fit various size beverage containers wherein the can incorporates an improved mounting configuration for mounting the can. The beverage container holder further comprises a mounting ring which is separately mountable to the support platform. Preferably, the mounting ring is an annular shape that surrounds a corresponding opening formed in the support platform and in which the can is to be received. Both the cylindrical can and the mounting ring can be made from plastic resin that fluoresces in the dark or is adapted for illumination for increased visibility in low light settings.
As to the improved mounting arrangement, the mounting ring includes at least one cam track formed on an exterior surface of the mounting ring and which is adapted to receive a detent provided in the can. The detent projects into the cam track when the can and mounting ring are aligned with each other and the can is seated on the mounting ring. Thereafter, the can is rotated to slide the detent along the cam track and then into a locking engagement on the cam track thus positively restraining the can in a locked condition so the can is rigidly affixed to the support platform.
The mounting ring includes separate fasteners that affix the mounting ring in a non-rotatable fixed condition on the support platform. These fasteners may include screws which are inserted downwardly through fastener bores in the mounting ring and threadedly engage the support platform. The mounting ring fasteners can also include flexible ridged projections that can be inserted downwardly into the support platform that affix the mounting ring in fixed condition on the support platform. Thus, the overall beverage container holder is positively fastened to the support platform by conventional fasteners. The rim of the can then overlies these fasteners and encloses same to provide an improved aesthetic appearance to the overall beverage container.
This provides an improved mounting structure by which the can may be readily mounted to the support platform, and also provides an improved aesthetic appearance to the container holder since the fasteners used to secure the mounting ring to the support platform are in turn covered by the rim of the can. To increase the visibility in dark conditions, the cylindrical can, the rim of the can, or the mounting ring can be made to emit light by manufacturing these components with materials that glow in the dark, fluorescent materials, or clear materials that capture and transmit light from generating sources.
Other objects and purposes of the invention, and variations thereof, will be apparent upon reading the following specification and inspecting the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a bottom isometric view of the beverage container holder of the invention showing a holder can mounted to a mounting ring.
FIG. 2 is a plan view of the can.
FIG. 3 is a front elevational view of the can.
FIG. 4 is an exploded elevational view showing the can and mounting ring being mounted with screw fasteners to a support platform of a vehicle.
FIG. 5 is a plan view of the mounting ring with screw fasteners.
FIG. 6 is an enlarged elevational view of the holder assembly mounted to the vehicle platform using the screw fasteners.
FIG. 7 is a partial enlarged view of the rim of the can.
FIG. 8 is an enlarged partial view of the can rim with phantom lines provided therein that illustrate a detent therein.
FIG. 9 illustrates the engagement of the detent with the mounting ring.
FIG. 10 is a plan view of the mounting ring with circumferentially spaced detents.
FIG. 11 is a side view of the mounting ring from a first orientation.
FIG. 12 is a front elevational view of the mounting ring from a second orientation.
FIG. 13 is an enlarged view of a locking track which cooperates with a respective detent.
FIG. 14 is a front elevational view of the locking track from a second orientation.
FIG. 15 is a partial plan view of a locking track illustrating a detent being moved between locked and unlocked positions.
FIG. 16 is an exploded elevational view showing the can and mounting ring being mounted with flexible finger fasteners to a support platform of a vehicle.
FIG. 17 is a plan view of the mounting ring with flexible finger fasteners.
FIG. 18 is an enlarged elevational view of the holder assembly mounted to the vehicle platform using the flexible finger fasteners.
FIG. 19 is a bottom view of the holder assembly using the flexible finger fasteners.
FIG. 20 is a top view of the mounting ring with circumferentially spaced flexible finger fasteners and detents.
FIG. 21 is a bottom view of the mounting ring with circumferentially spaced flexible finger fasteners and detents.
Certain terminology will be used in the following description for convenience and reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.
DETAILED DESCRIPTION
Referring to FIG. 1 , the invention relates to a holder 10 for beverage containers which is adapted for mounting to a generally horizontal support surface or platform such as the structure of a vehicle or vessel. The holder 10 particularly is suited for mounting to any desired location as an add-on component to the existing structure of the vehicle or vessel.
The holder 10 is an assembly comprising a mounting ring 12 which is configured for mounting to the support platform by a plurality of screws 14 . After affixing the mounting ring 12 in position, a generally cylindrical can or container 15 is provided which fits through the center portion of the mounting ring 12 and is affixed thereto by locking rotation of the can 15 in the direction of reference arrow 16 .
Referring more particularly to the construction of the can 15 as illustrated in FIGS. 2 and 3 , the can 15 comprises a main cylinder body 17 having a main body wall 18 which defines a substantial vertical dimension of the overall height of the can 15 . The main cylinder body 17 then transitions downwardly and turns inwardly into a narrower bottom cylinder body 19 which preferably has a reduced diameter as compared to the main cylinder body 17 . The bottom cylinder 19 is defined by a bottom cylinder wall 20 and then again transitions radially inwardly to define the bottom can wall 22 . The differing diameters of the main cylinder body 17 and bottom cylinder 19 allows for usage of different size beverage containers within the can 15 .
The bottom of the can is also provided with a thin elastomer pad 24 ( FIG. 2 ) having a center hole, while the bottom can wall 22 includes a drain nipple 26 . Since the holder 10 of the invention is provided for use in marine environments, the nipple 26 serves as a drain for any water from the environment which collects therein. Also, the drain nipple 26 can serve as a spill tube for allowing spillage to also drain to a suitable location. Typically, a drain tube (not illustrated) is attached to the nipple 26 by a suitable elbow.
Next as to the top of the can 15 , the main cylinder body 17 transitions upwardly and terminates at a circumferential rim 28 which defines the can opening 29 that allows access to the interior compartment defined within the can 15 . Generally, the rim 28 projects radially outwardly from the main body wall 18 and has a plurality of circumferentially spaced apart locking formations 31 which preferably serve as detents for engagement with the mounting ring 12 as will be discussed herein.
Referring more particularly to FIG. 4 , the holder 10 is typically mounted to any suitable support platform 32 on the upper surface 33 thereof. Preferably the support platform 32 is formed with a circular bore 34 which opens upwardly for receipt of the holder can 15 therein.
FIG. 4 generally illustrates the assembly of the holder 10 wherein the mounting ring 12 is first positioned over the bore or pocket 34 as indicated by reference arrow 36 and then suitable fasteners such as screws 14 are inserted downwardly therethrough as indicated by reference arrow 37 . This positively fixedly secures the mounting ring 12 to the upper surface 33 of the support platform 32 and allows for downward engagement of the can 15 therewith. In particular, the can 15 is aligned with the mounting ring 12 and platform bore 34 in coaxial alignment therewith and then displaced downwardly as indicated by reference arrow 38 so as to insert the can 15 into the bore 34 and ring 12 such that the can rim 28 is seated in overlying engagement with the mounting ring 12 . When positioning the can 15 , the detents 31 on the can rim 28 are aligned with corresponding locking formations in the mounting ring 12 , namely cam slots 40 which allows the can 15 to be fitted downwardly in a fully seated condition on the mounting ring 12 . Thereafter, the can 15 is rotated as generally indicated by reference arrow 41 to engage the cooperating locking formations 31 and 40 together and lock the can 15 to the ring 12 .
The embodiment can include any type of bayonet connection such that two surfaces are turned in opposite directions to guide a first surface into a second surface slot that prevents the first surface from being removed. The can is held into position to prevent it from backing out. To disconnect the two surfaces the user pushes the two surfaces together to overcome the frictional forces holding the can in its locked position by using a fraction of a turn to reverse the locking turn.
As seen in FIG. 5 , the fasteners 14 fit downwardly in circumferentially spaced relation through the mounting ring 12 to secure the mounting ring 12 to the support platform 32 as also generally illustrated in FIG. 6 .
When secured in position, the rim 28 substantially encloses the mounting ring 12 as illustrated in FIG. 6 and the can 15 is then mounted so that it only projects slightly above the upper surface 33 of the support platform 32 .
More particularly as to the arrangement of the locking structure on the can rim 28 , FIGS. 7-9 best illustrate this locking structure and namely the detents 31 . As seen in FIGS. 7-9 , the main body wall 18 extends vertically upwardly to its upper terminal edge 45 . At this upper terminal edge 45 , the main body wall 18 then is outturned and transitions into the rim 28 , and specifically transitions into an upper rim wall 46 which extends radially outwardly. The upper rim wall 46 then turns an additional corner 47 so as to define a downwardly projecting outer rim wall 48 which terminates at a bottom edge 49 . This outer rim wall 48 has an inside surface 50 which faces radially towards the opposing outside surface 51 of the main body wall 18 to thereby define an annular ring-receiving channel 53 which is adapted to fit over the mounting ring 12 as can be seen in FIG. 9 . This channel 53 opens downwardly and has a width generally corresponding to the overall width of the can rim 28 .
To secure the can 15 to the mounting ring 12 , a plurality of the locking formations 31 are provided and preferably three such formations are provided at equal angular spacing about the circumference of the outer rim wall 48 . Preferably the locking formations 31 are formed as inwardly projecting detents 55 which project a small radial distance into the ring channel 53 and also only have a small angular dimension as illustrated in FIGS. 6 and 15 wherein these detents 55 are defined by opposite angularly-spaced end surfaces 56 and 57 .
Preferably, the can 15 is formed as a single unitary body of a suitable corrosion-resistant material including stainless steel, plastics or other resins that are adapted to emit or transmit light.
Turning next to the mounting ring 12 , the mounting ring 12 is illustrated in FIGS. 5 and 10 - 12 . This mounting ring 12 has an annular shape defined by inner and outer circumferential surfaces 59 and 60 , and top and bottom surfaces 61 and 62 . Preferably, the mounting ring 12 is formed from a molded plastic material.
Referring to FIGS. 10 and 15 , arcuate lengths of the ring 12 are formed with recessed channels 64 which extend between opposite ends 65 and 66 and are defined on opposite sides by channel walls 67 and 68 ( FIG. 15 ). These channels 64 preferably reduce the material used for the mounting ring 12 during molding thereof.
Along the length of the arcuate channels 64 , bosses 70 are provided through which the fastener 14 , are threadedly engaged with the support platform 32 . Preferably as seen in FIG. 10 , the bosses 70 are positioned closest to the cam slots 40 to best hold the cam slots 40 in position against the upper support surface 33 during locking rotation of the can 15 .
As to the cam slots 40 , these cam slots 40 are positioned at equal angular distances from each other as generally illustrated in FIGS. 10-12 and as such are aligned with the detents 55 of the can 15 as diagrammatically illustrated in FIGS. 10 and 12 .
As to the specific structure of these cam slots 40 , FIGS. 13-15 best illustrate the cam slots 40 .
Generally, each cam slot 40 includes a vertical entry passage 72 which opens vertically through the entire thickness of the mounting ring 12 and has a circumferential distance defined by the full thickness passage side face 73 and the partial thickness passage side face 74 . The bottom end of the entry passage 72 then opens circumferentially into a cam section 75 which is open on the bottom side thereof but is defined by the top cam face 76 . The cam face 76 generally slopes along a first sloped section 77 until it reaches an inclined rib 78 . Circumferentially past the rib 78 , a flat lock seat 79 is formed. It is noted that the dimension of the lock seat 79 is shallower than the first sloped section 77 which progressively varies along the length thereof.
During mounting of the can 15 to the mounting ring 12 , the detents 55 are first aligned with the entry passage 72 as generally illustrated in FIG. 15 which shows the detent 55 in a first unlocked position indicated by reference arrow 81 . This unlocked position 81 also is diagrammatically illustrated in FIGS. 10 and 12 . Once the can 15 is fully seated with the mounting ring 12 being completely seated within the ring channel 53 of the can rim 28 shown in FIG. 9 , the can 15 can then be rotated as indicated by reference arrow 82 in FIG. 10 . This causes the detents 55 to rotate or translate circumferentially to the fully locked position 83 shown in FIGS. 12 and 15 . In particular the detents 55 then ride over the cam rib 78 of the cam slot 40 and then seat within the lock seat 79 thereof. In particular, the inwardly projecting detent 55 generally rides along the outer edge portion of the cam slot 40 along the outer cam edge 85 . FIG. 9 illustrates the detent 55 generally in contact with the cam rib 78 as it rides thereover and prepares to either move into the lock seat 79 or back to the slope section 77 depicted in FIG. 9 in phantom outline. This riding of the detent 55 along the slope cam section 77 draws the can rim 28 downwardly into tight-fitting engagement with the mounting ring 12 . As the detent 55 rides over the cam rib 78 , a positive resistance to locking is felt and then this resistance drops off slightly as the detent 55 then aligns with the lock seat 79 in the locked position 83 ( FIG. 15 ). The detent end face 57 then faces towards and is positioned for contact with the rib 78 so as to resist return rotation of the cam 15 . Therefore, this slope section 77 causes a positive drawing of the can 15 downwardly towards the support platform 32 while the rib 78 then causes the detent 55 to move over into a positively locked position 83 .
During assembly, the mounting ring 12 is first positioned and fastened to the support surface 32 by the fasteners 14 . Thereafter, the can 15 is positioned with the detents 55 thereof in alignment with the corresponding entry passages 72 of the cam slots 40 . As the can 15 is moved downwardly to the fully seated position with the mounting ring 12 seated fully within the ring channel 53 ( FIG. 9 ), the can 15 is then rotated as generally depicted in FIGS. 10 and 15 to the positively locked position 83 . In this manner, an improved mounting arrangement is provided for positively locking the beverage containing can 15 in position on a desired vehicle or vessel.
Another embodiment of the present invention includes, as seen in FIGS. 16 and 17 , an assembly comprising a mounting ring 12 which is configured for mounting to the support platform by circumferentially spaced fasteners 84 which frictionally engage the support platform 32 . After affixing the mounting ring 12 in position, a generally cylindrical can or container 15 is provided which fits through the center portion of the mounting ring 12 and is affixed thereto by locking rotation of the can 15 in the direction of reference arrow 16 . The mounting ring 12 with the fasteners 84 on the mounting ring 12 fit downwardly in circumferentially spaced relation through the bore 34 to secure the mounting ring 12 to the support platform 32 as also generally illustrated in FIG. 18 . The fasteners 84 comprise flexible fingers 87 that extend downwardly and include detents 89 that extend outwardly to frictionally engage the support platform 32 in the bore 34 also see FIG. 17 .
FIG. 16 generally illustrates the assembly of the holder 10 wherein the mounting ring 12 is first positioned over the bore 34 as indicated by reference arrow 36 and then suitable fasteners 84 comprising circumferentially spaced and downwardly extending flexible fingers 87 with outwardly radiating detents 89 are inserted downwardly therethrough as indicated by reference arrow 37 . Alternative fasteners could also be used, these include but are not limited to; any friction type fastener of smooth, ridged, continuous or discontinuous design; adhesive fasteners where an adhesive coating of any type may be applied to either the support platform 32 or the mounting ring 12 or both with optional flexible coverings placed on the adhesive until it is to be fixed; screw type fasteners where metal or plastic screws of any shape are used; or any other type of fastener know to one skilled in the art that can be used to secure the mounting ring to the support platform.
The fasteners 84 positively fixedly secure the mounting ring 12 to the upper surface 33 of the support platform 32 and allows for downward engagement of the can 15 therewith. In particular, the can 15 is aligned with the mounting ring 12 and platform bore 34 in coaxial alignment therewith and then displaced downwardly as indicated by reference arrow 38 so as to insert the can 15 into the bore 34 and ring 12 such that the can rim 28 is seated in overlying engagement with the mounting ring 12 . When positioning the can 15 , the detents 31 on the can rim 28 are aligned with corresponding locking formations in the mounting ring 12 , namely cam slots 40 which allows the can 15 to be fitted downwardly in a fully seated condition on the mounting ring 12 . Thereafter, the can 15 is rotated as generally indicated by reference arrow 41 to engage the cooperating locking formations 31 and 40 together and lock the can 15 to the ring 12 .
As seen in FIG. 18 , the fasteners 84 comprise of downwardly extending fingers 87 with outwardly radiating detents 89 that frictionally engage the support platform 32 to affix the mounting ring 12 in the support platform 32 . Preferably, there are a plurality of detents 89 to provide increased frictional engagement to the support platform 32 . It is also contemplated in this embodiment that a single detent 89 can be used to frictionally engage the mounting 12 . The detents 89 can be made of various shapes and sizes. For instance, the detents 89 can have a triangular shaped cross-section, in which a point of the triangularly shaped detent frictionally engages the support platform 32 to help prevent upward removal of the mounting ring 12 from the support platform 32 . In some embodiments, the detents 89 are formed as a plurality of ridges on the downward fingers 87 in which the detents 89 span the axial width of the finger 87 or are limited to a small width of the finger 87 . In other embodiments, the detents 89 are formed as a plurality of conical protrusions on each finger 87 .
As seen in FIG. 21 , for example, the mounting ring 12 includes three circumferentially spaced fasteners 84 but other embodiments, depending on the support platform 32 material and construction, could include more or less fasteners 84 to provide the optimal frictional engagement at the lowest manufacturing cost In some embodiments for increased engagement and affixing to the support platform 32 , the fastener 84 can be adapted as one continuous support ring extending downwardly from the mounting ring 12 with a plurality of detents 89 that spans the entire circumference of the mounting ring 12 thereby providing circumferential affixing of the mounting ring 12 to the support platform 32 .
Further embodiment modifications include using materials for the holder 10 , cylindrical can 15 , the rim of the can 28 , or the mounting ring 12 which can be manufactured with either phosphorescent materials, fluorescent materials, or other substances that radiate visible light after being energized to provide increased visibility in low light conditions.
Further embodiment modifications include using materials for the holder 10 , cylindrical can 15 , the rim of the can 28 , or the mounting ring 12 which can be manufactured with either translucent or transparent materials that capture and transmit light from generating sources, such as a light positioned below or next to the beverage container holder 10 to provide back illumination for enhanced visibility in the dark.
Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention. | 4y
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This application is a continuation application of PCT/AU94/00740, filed Nov. 30, 1994.
FIELD OF THE INVENTION
This invention relates to chaperonin 10 otherwise known as cpn10.
BACKGROUND OF THE INVENTION
Chaperonins belong to a wider class of molecular chaperones, molecules involved in post-translational folding, targeting and assembly of other proteins, but which do not themselves form part of the final assembled structure as discussed by Ellis et al., 1991, Annu. Rev. Biochem. 60 321-347. Most molecular chaperones are "heat shock" or "stress" proteins (hsp); i.e. their production is induced or increased by a variety of cellular insults (such as metabolic disruption, oxygen radicals, inflammation, infection and transformation), heat being only one of the better studies stresses as reviewed by Lindquist et al., 1988, Annu. Rev. Genet. 22 631-677. As well as these quantitative changes in specific protein levels, stress can induce the movement of constitutively produced stress proteins to different cellular compartments as referred to in the Lindquist reference mentioned above. The heat shock response is one of the most highly conserved genetic system known and the various heat shock protein families are among the most evolutionarily stable proteins in existence. As well as enabling cells to cope under adverse conditions, members of these families perform essential functions in normal cells.
There are two types of cpn molecules, cpn60 (monomeric M r ˜60 000) and cpn10 (monomeric M r ˜10 000). Cpn60 has been studied extensively. It has been identified in all bacteria, mitochondria and plastids examined, and a cytoplasmic form, TCP-1, has been identified in eukaryotic cells; its presence on the surface of some cells has been reported, although this has been questioned in the Ellis reference referred to above and also in van Eden, 1991, Immunol. Reviews 121 5-28. Until very recently, cpn10 had been identified only in bacteria but structural and functional equivalents have now been found in chloroplasts (Bertsch et al., 1992, Proceedings of the National Academy of Sciences USA 89 8696-8700) and in rat (Hartman et al., 1992, Proceedings of the National Academy of Sciences USA 89 3394-3398) and bovine liver mitochondria (Lubben et al., 1990, Proceedings of the National Academy of Sciences USA 87 7683-7687).
Cpn60 and cpn10 interact functionally, in the presence of ATP, to mediate protein assembly. Instances of cpn10 acting independently of cpn60 have not yet been reported but cpn60, apparently acting alone, has been implicated in quite disparate events. For example, it is an immuno-dominant target of both antibody and T-cell responses during bacterial infections but, because the protein is so highly conserved, self reactivity is generated. Healthy individuals may use this self-recognition to eliminate transformed and infected autologous cells but defects in control of such recognition may lead to autoimmune disease as discussed by van Eden, 1991, Immunol. Reviews 121 5-28. Not surprisingly, cpn60 has been associated with conditions such as rheumatoid arthritis. There is thus a growing awareness that molecular chaperones, with their capacity to bind to and alter the conformation of a wide variety of polypeptides, may occupy key roles in cellular functions other than protein biogenesis. Reference may also be made to Hartman et al., 1993, Proceedings of the National Academy of Sciences USA 90 2276-2280 which describes the stabilization of protein molecules using cpn10 and cpn60.
It can also be established that for mammalian cpn10's, there is a very close sequence homology. Thus, for example, the rat cpn10 molecule (Hartman et al., 1992, Proceedings of the National Academy of Sciences USA 80 3394-3398) has greater than 99% homology with the structure of bovine cpn10 reported in EMBL Data Base Directory under MT BTC PN10 which was submitted by J. E. Walker, MRC Lab. of Molecular Biology, Hills Road, Cambridge, UK. This has to be contrasted with bacterial cpn10's which have an average degree of homology with rat chaperonin 10 of only 34% (Hartman et al., 1992).
Early Pregnancy Factor (EPF)
EPF was first described as a pregnancy associated substance (Morton et al., 1976, Proc. R. Soc. B. 193 413-419) and its discovery created considerable interest as it enabled the detection of a potential pregnancy within 6-24 hours of fertilisation. Initially EPF was assigned a role as an immuno-suppressant by virtue of its ability to release suppressor factors from lymphocytes (Rolfe et al., 1988, Clin. exp. Immunol. 73 219-225). These suppressor factors depress the delayed type hypersensitivity reaction in mice and therefore might suppress a possible maternal immune response against the antigenically alien fetus. More recent studies have shown that production of EPF is not confined to pregnancy. It is a product of primary and neoplastic cell proliferation and under these conditions acts as a growth factor (Quinn et al., 1990, Clin. exp. Immunol. 80 100-108; Cancer Immunol. Immunother, 1992, 34 265-271). EPF is also a product of platelet activation and it is proposed therefore that it may play a part in wound healing and skin repair (Cavanagh et al., 1991, Journal Reproduction and Fertility 93, 355-365).
To date, the rosette inhibition test remains the only means of detecting EPF in complex biological mixtures (Morton et al., 1976, Proc R Soc B 413-419). This assay is dependent on the original finding of Bach and Antoine, 1968, Nature (Lond) 217 658-659 that an immunosuppressive anti-lymphocyte serum (ALS) can inhibit spontaneous rosette formation in vitro between lymphocytes and heterologous red blood cells. A modification of the assay was introduced to detect EPF after it was demonstrated that lymphocytes, preincubated in EPF, give a significantly higher rosette inhibition titre (RIT) with an ALS than do lymphocytes from the same donor without EPF as described in the 1976 reference above. This test has been described in detail in the above 1976 reference as well as in Morton et al., 1987, in "In Current Topics in Developmental Biology" Vol 23 73-92, Academic Press, San Diego, but briefly it involves a cascade of events with EPF binding to lymphocytes and sequentially inducing the release of suppressor factors (Rolfe et al., 1988, Clin. exp. Immunol. 73 219-225); (Rolfe et al., 1989, Immunol. Cell Biol. 67 205-208).
In Athanasas-Platsis et al., 1989, Journal Reproduction and Fertility 87 495-502 and Athanasas-Platsis et al., 1991, Journal Reproduction and Fertility 92 443-451, there is described the production of monoclonal and polyclonal antibodies to EPF and passive immunization of pregnant mice with these antibodies which causes loss of embryonic viability. These studies established that EPF is necessary for the successful establishment of pregnancy.
In Quinn et al., 1990, Clin. exp. Immunol. 80 100-108, it is proposed that EPF is a growth regulated product of cultured tumour and transformed cells. These cells are also dependent upon EPF for continued growth i.e. EPF acts in an autocrine mode.
It has been established that EPF plays a role in promoting tumour growth since the growth of tumour cells can be significantly retarded by anti-EPF mAbs. In addition this reference suggests that hybridomas producing high affinity anti-EPF antibodies may be inherently unstable.
In Quinn et al., 1992, Cancer Immunol. Immunother, 34 265-271, there is also described the effect of monoclonal antibodies (mAbs) to EPF on the in vivo growth of transplantable murine tumours. The main thrust of this reference is that neutralisation of EPF retards tumour growth in vivo.
It is clear from the above Quinn et al. 1992 reference that when cancer is in the very early stage of growth, neutralisation of EPF by anti-EPF mAb will prevent its development. However, once the cancer becomes established, treatment with these mAbs will retard but not entirely destroy the tumour.
Other references in regard to the role of EPF in tumour growth include Quinn, 1991, Immunol. Cell Biol. 69 1-6 and Quinn, K. A. in a PhD thesis entitled "Early pregnancy factor: a novel factor involved in cell proliferation 11 from the University of Queensland in Australia in 1991.
EPF is reviewed in detail by Morton et al., 1992, Early Pregnancy Factor, Seminars in Reproductive Endocrinology 10 72-82. The site and regulation of EPF production is described, followed by the purification of EPF from platelets and the relationship of the purified product to EPF derived from other sources. This review also discusses certain aspects of the bioassay for EPF (i.e. the rosette inhibition test) including monitoring purification procedures and investigating sources of production. The biological activity of EPF is discussed and possible clinical applications of EPF and its antagonists are described.
Morton et al., 1992, Reprod. Fertil Dev. 4 411-422 reviews previous publications describing the immuno suppressive and growth factor properties of EPF. The role of EPF in maintaining the pre-embryo is also discussed in this reference.
Both of the abovementioned references, which are essentially review articles, describe the preparation of purified EPF for blood platelets which included the initial sequential steps of heat extraction of the platelets, cation exchange chromatography on SP-SEPHADEX, crosslinked dextran beads C-25, affinity chromatography on Heparin-SEPHAROSE, crosslinked agarose beads CL-6B and Concanavalin-A-Sepharose 4B. The final purification of EPF was achieved by high performance hydrophobic interaction chromatography, followed by three reversed phase (RP)-HPLC steps. After the final RP-HPLC step, EPF was isolated as single UV absorbing peak coincident with biological activity, well separated from a number of minor contaminants. The biological and radioactivity of an iodinated sample of this material eluted with identical retention time when fractionated under the same conditions. When analysed by SDS-PAGE and visualised by autoradiography, the iodinated material ran as a single band of approximate Mr 10,000, again coincident with biological activity. The approximate yield of EPF by this method was 5 μg per 100 platelet units.
This demonstrates that it was necessary to use this complex purification procedure to obtain only a small amount of native EPF and thus this method could not be used on a commercial scale. In this regard, the only practical sources known for obtaining native EPF at this time were platelets and regenerating liver.
Surprisingly, in accordance with the present invention, the final fractionated EPF when subjected to sequencing as more fully described hereinafter found that the structure of native EPF corresponded to chaperonin 10 which could not have been predicted from the aforementioned prior art.
This unexpected discovery as will be apparent from the disclosure hereinafter has now been reduced to practice in that recombinant chaperonin 10 has been found to have all the biological activity previously associated with EPF and thus EPF can now be produced commercially which was not the case previously using suitable techniques for producing recombinant cpn10. It will also be apparent that EPF can now be produced synthetically.
SUMMARY OF THE INVENTION
In one aspect, the invention resides in the discovery that cpn10 is EPF and has the hitherto unknown or unsuspected properties demonstrated by EPF. The unknown or unsuspected properties of cpn10 include extracellular activities such as the ability to act as a growth factor and an immunosuppressive factor. In another aspect the invention provides one or more methods for using cpn10 to exploit the unknown or unsuspected properties of cpn10. The one or more methods includes a method of using cpn10 to promote growth and a method of using cpn10 to suppress immunological activity.
The term "cpn10" as used herein, insofar as methods of promotion of cell growth and immunosuppression are concerned, includes within its scope recombinant cpn10 as well as cpn10 which is produced synthetically. The term "cpn10" also includes eucaryotic cpn10 as well as procaryotic cpn10 inclusive of groES or derivatives of recombinant cpn10. The recombinant cpn10 may be produced by recombinant DNA technology as described hereinafter. The term also includes biological fragments.
The present invention also includes within its scope a modified recombinant cpn10 as well as derivatives and peptide fragments derived therefrom.
The invention in another aspect refers to an assay for detection of cpn10 which includes the detection of native cpn10.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1a
Purification of EPF. Heat extracted human platelets (100 units) were fractionated on SP-SEPHADEX and Heparin SEPHAROSE, then applied to a TSK-Phenyl 5PW column and eluted with a reverse salt gradient. Fractions were tested in the rosette inhibition test (based on EPF's capacity to augment the rosette inhibiting activity of an immunosuppressive antilymphocyte serum).
FIG. 1b
Active fractions (Π) from (a) were fractionated by RP-HPLC-1.
FIG. 1c
Active fractions (Π) from (b) were fractionated by RP-HPLC-2.
FIG. 1d
Active fractions (Π) from (c) were fractionated by RP-HPLC-3.
FIG. 1e
Interaction of immobilised monoclonal anti-EPF antibody 5/341 with active fractions from (d) and equivalent fractions from human pregnancy serum, 6 d gestation (10 ml); human pregnancy urine, up to 1 month gestation (10 liter); medium conditioned by oestrous mouse ovaries (100) stimulated with prolactin and mouse embryo-conditioned medium (ovary CM); serum free medium conditioned by the bovine kidney cell line MDBK (MDBK-CM; ATCC CCL 22, 10 liter); rat serum obtained 24 h post-partial hepatectomy (post-pH, 10 ml); rat liver obtained 24 h post-pH (40 g); all fractionated as in (a) to (d). Anti-EPF bound and unbound fractions were tested in the rosette inhibition test, specificity was demonstrated by comparison with a parallel experiment using irrelevant antibody in which activity was not bound.
FIG. 2a
Analysis of EPF purified from 300 units human platelets as in FIG. 1A. Determination of monomeric size. Iodinated EPF was fractionated by SDS-PAGE, 29 the gel sliced (2 mm wide slices) and the distribution of radioactivity and biological activity compared. (Inset) Direct Coomassie Blue staining of the same preparation.
FIG. 2b-1
Ion-spray mass spectrum of EPF, displayed as multiply protonated molecular ions.
FIG. 2b-2
Computer reconstruction as molecular mass.
FIG. 2c
Amino-acid sequence (single letter code) of peptides derived from human EPF, compared with rat cpn10 (underlined). EPF was digested with endoproteinase lys C and endoproteinase glu C, the resultant peptides separated by RP-HPLC and sequenced. The sequence of individual fragments is shown; all except 74-101 were derived from the lys digest.
FIG. 3a
Peak fractions in the excluded volume of a TSK G3000SW gel permeation column, following application of a cpn60-EPF mixture +Mg 2+ ATP, were analysed by SDS-PAGE (Schagger et al., 1987) and stained with silver (Morrissey, 1981). Left lane, +ATP; right lane -ATP. (Cpn60 is a decatetramer, M, 840 000; column exclusion limit >300 000. Higher M r bands on SDS gel are oligomeric forms of groEL).
FIG. 3b
Immobilised cpn60 was mixed with human pregnancy serum (6 d gestation) in the presence or absence of Mg 2+ ATP. Unbound and bound fractions (the latter recovered from the gel by removal of ATP with EDTA) were then tested in the rosette inhibition test. Results are expressed as limiting dose, the highest dilution of sample giving a positive result in the rosette inhibition test.
FIG. 4
pRM1
FIG. 5
pRM2
FIG. 6
pRM3
FIG. 7
Preparation of antibodies to cpn10
FIG. 8
Detection of anti-cpn10 antibodies in rabbit serum by ELISA
FIG. 9
Competitive binding assay for cpn10
FIG. 10
% inhibition of antibody binding
FIG. 11
Time course of recombinant cpn10 and platelet cpn10 activity in serum of mice after injection i.p.
FIG. 12
The effect of rcpn10 on wound contraction in mice. Wounds (˜45 mm 2 ) were created in mice, 1 μg rcpn10 or control solutions (5 μl) applied topically × 2 daily and the size of wound area on groups of mice measured at times indicated (means±SD); d 0, n=10 d 1-d 3, n=3, d 4-d 7, n=2*p<0.05 compared with buffer control group.
FIG. 13
Effect of the treatment regimen on development of EAE in rats.
FIG. 14
Effect of cpn10 on development of EAE in rats.
FIG. 15
Effect of cpn10 on development of EAE in rats.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention includes within its scope the following.
Assay For cpn10
The detection of cpn10 in serum or other biological fluids using monoclonal or polyclonal antibodies against recombinant or synthetic cpn10or against modifications or fragments thereof alone or in combination with each other or with cpn60 (in the presence of ATP or other nucleotide triphosphates) for the purpose of:
(a) pregnancy diagnosis in any mammalian species;
(b) monitoring embryonic well-being in "at-risk" pregnancies;
(c) diagnosis of tumours; and
(d) monitoring patients after surgical removal of tumours.
Treatment With CPM10
The use of recombinant cpn10 as a growth factor or immunosuppressant in the treatment of:
(a) skin or organ grafts;
(b) wound healing, tissue repair or regeneration of tissue;
(c) autoimmune disease;
(d) infertility/miscarriage;
(e) allergic disease; and
(f) inflammatory conditions.
Experimental
Purification of cpn10
(a) Purification of Human EPF from Human Blood Platelets (FIG. 1a, 1b, 1c, 1d)
Extraction
Platelet concentrates (from the Blood Bank), up to 7 days clinically outdated, were washed with Tyrodes buffer, following the techniques described in Methods in Enzymology, 1989, 169 7-11, snap frozen in liquid N 2 and stored at -70° C.
Immediately prior to purification, approximately 100 washed platelet units were thawed in a boiling water bath, then held at 75-85° C for 15 min with continuous, gentle stirring. After cooling on ice, cellular debris was removed by centrifugation (8000 g, 20 min, 4° C.) and the pellet extracted twice by homogenisation in 0.05 M-acetic acid/0.1 M-NaCl/0.1 mg/ml sodium azide pH 3.0 followed by centrifugation (8 000 g, 15 min 4° C.). The three supernatants were pooled giving a total extract volume of 500-600ml.
Ion -Exchange Chromatography
This extract from 100 platelet units was adjusted to pH 3.0 with conc. HCl and stirred gently, overnight, 4° C., with 250ml SP-SEPHADEX, crosslinked dextran beads C-25 (Pharmacia-LKB), previously swollen and equilibrated with 0.05 M-acetic acid/0.1 M-NaClpH 3.0. The gel was then packed into a column washed with 20 vol of the same buffer and eluted with 5 vol 0.5 M-sodium phosphate buffer/0.05 M-NaClpH 7.5. The gel was then discarded.
Affinity Chromatography
The SP-SEPHADEX, crosslinked dextran beads; eluate was adjusted to pH 6.3-6.4 with conc. HCl and applied to a column of Heparin-SEPHAROSE, crosslinked agarose beads CL-6B (2.5×7.5 cm; Pharmacia-LKB) previously equilibrated with 0.05 M-sodium phosphate buffer 0.05 M-NaCl pH 6.3. The column was then washed with 5 vol of the same buffer and eluted with 5 vol 0.05 M-Tris-HCl/5 mM-CaCl 2 /0.2 M-NaCl pH 7.5, applied in the reverse direction to that used for sample application.
High Performance hydrophobic Interaction Chromatography (HIC-h.p.l.c.)
Solid (NH 4 ), 2 SO 4 was added to the Heparin-SEPHAROSE, crosslinked agarose beads eluate to a final concentration of 2 M and, after passage through an 0.45 μm filter, the sample was pumped through a dedicated solvent line onto a TSK Phenyl 5PW column (7.5×75 mm, Pharmacia-LKB), previously equilibrated with 0.1 M-Tris-HCl pH 7.0/5mM CaCl 2 /2 M-(NH 4 ) 2 SO 4 . The column was washed with 10 vol of the same buffer and eluted with a 50 min linear Gradient from this buffer to 0.1 M-Tris-HCl pH 7.015 mM-CaCl 2 /10% acetonitrile. (FIG. 1a)
RP-h.p.l.c.
Active HIC-h.p.l.c. fractions were pooled, then fractionated on a C 3 column (Ultrapore RPSC. Beckman Instruments) using a solvent system consisting of A, 0.04 M Tris/HCl pH 7.0/5 mM-CaCl 2 and B, 0.04 M-Tris/HCl pH 7.0/5 mM-CaCl 2 /80% (v/v) acetonitrile. The column was equilibrated with Solvent A prior to sample application, after which it was washed with 5 vol solvent A and eluted with a 30 min linear gradient from this solvent to 75% solvent B. (FIG. 1b)
RP-h.p.l.c.2
Active fractions from RP-h.p.l.c.-1 of several 100 unit platelet preparations were pooled, EDTA and DTT added to a final concentration of 20mM and 1mM respectively and the mixture allowed to stand for 0.5-1 h, 4° C. Following dilution with 2 vol solvent A, it was applied to a C 3 column, dedicated to this and subsequent steps, and fractionated as described for RP-h.p.l.c.-1, but omitting CaCl 2 . (FIG. 1c)
Rph.p.l.c.3
Active fractions from RP-h.p.l.c.-2 were pooled, trifluoroacetic acid (TFA) added to a final concentration of 0.1% and, following dilution with 2 vol 0.1% TFA, the mixture was applied to the C 3 column, which had been equilibrated previously with 0.1% TFA. The column was then eluted with a 30 min linear gradient from this solvent to 60% (v/v) acetonitrile/0. 1% TFA, followed by a 3 min linear gradient to 90% (v/v) acetonitrile/0. 1% TFA. Active fractions were pooled. (FIG. 1d)
One unit represents platelets from a single blood donation which is approximately 500 ml. The "active fractions" were fractions active in the rosette inhibition test.
Purification of EPF from other sources
EPF has been purified from various sources as discussed in Cavanagh & Morton, 1994, Eur. J. Biochem. 222 551-560; Quinn et al., 1994, Hepatology 20 No 5 1294-1302.
In all instances, biological activity followed the same pattern throughout the complex purification scheme described above for human platelets. Furthermore the final active fraction from all sources was bound specifically by an immobilised monoclonal anti-EPF and could be recovered virtually quantitatively (see FIG. 1e).
These studies are important for several reasons:
A. The biochemical and immunological similarity observed with all these materials provides strong evidence that the bioassay is detecting a single substance or closely related family of substances acting in diverse biological situations.
B. The active agents purified from all of these materials are from several to many orders of magnitude more potent than virtually all of the substances previously reported to be EPF. This confirms our surmise, based on detailed analysis of the EPF bioassay as discussed above, that activity associated with most putative EPF preparations must reflect the presence of a very minor contaminant.
C. The only source materials providing sufficient EPF to study at the protein (as opposed to activity) level were platelets and regenerating liver, yielding, respectively, an average of 15 μg per 100 units (equivalent to ˜50 liter blood) and 5 μg per 40 g tissue (liver remnant from 6 rats). It is immediately apparent that far more EPF is present within the cell than appears in the extracellular space; nevertheless, accumulated knowledge of the biology of EPF (reviewed recently in the abovementioned Morton et al. 1992 reference) indicates that this extracellular appearance is not fortuitous.
Human platelet-derived EPF, being most abundant, has been studied in some detail. On SDS-PAGE, it ran as a single band of Mr approx, 8.500, coincident with biological activity (see FIG. 2a); EPF from regenerating rat liver exhibited identical behaviour. Mass spectometry of the platelet material provided an accurate and precise determination of molecular mass 10 843.5±2 Da, along with definitive evidence of the high degree of homogeneity of the preparation (see FIG. 2b). Following attempts at Edman degradation, which indicated that the molecule is N-blocked, proteolytic cleavage of approx. 4 nmol EPF was undertaken. Resultant peptide fragments were separated by reversed-phase HPLC and subjected to sequencing by Edman degradation. Three areas of sequence containing 12 (fragment 1), 27 (fragment 2) and 33 (fragment 3) residues were found to correspond with residues 7 to 18-27-53 and 69 -101 (the C-terminus) in rat mitochondrial cpn10. In fragment 2, residue 52 was different (S in cpn10, G in rat cpn10, this change alone could account for human cpn10 being 30 Da larger than rat cpn10). All other residues were identical, consistent with the highly conserved nature of chaperonins (see FIG. 2c).
Since confirming sequence identity between EPF and cpn10 several studies of functional relationship have been performed, using rat mitochondrial cpn10 E. coli cpn10 (known as groES) and E. coli cpn60 (groEL). First it has been demonstrated that cpn10 can act as EPF. Rat cpn10 was tested in the EPF bioassay and found to be positive over the range of dilutions expected; this activity could be neutralised by monoclonal antibodies to EPF (see TABLE 1). Interestingly, E. coli cpn10, which is ˜ 40% homologous with rat cpn10, exhibited no activity in the bioassay (see TABLE 1): this is consistent with the observation that E. coli conditioned medium is not active in the EPF bioassay, while medium conditioned by all mammalian cell lines tested, as well as by yeast cells is active. Cpn60 was inactive in the bioassay and had no effect upon the activity of EPF. It was then shown that EPF can act as cpn10. EPF was mixed with cpn60 , in the presence or absence of ATP, and the mixture fractionated on a TSK G3000SW gel permeation column: resultant fractions were analysed by SDS-PAGE. Cpn60 is a decatetramer and elutes in the excluded volume of this column (exclusion limit 300 000). In the presence of ATP, but not in its absence, EPF also appears in this fraction, demonstrating formation of a stable complex with cpn60. This fraction was active in the EPF bioassay but the equivalent fraction from the experiment without ATP (where EPF did not associate with cpn60) was not (see FIG. 3a). Thus EPF and cpn10 activity reside in the same molecule.
These investigations provide unequivocal evidence that platelet-derived EPF is a structural and functional homologue of cpn10the relationship between cpn10 and activity in the rosette inhibition test was then examined (FIG. 3b). In the presence, but not in the absence of ATP, immobilised cpn60 could remove all activity from the archetypal source material, pregnancy serum and activity could be recovered by removing ATP from the immobilised complex. As with the experiment described in FIG. 3a, this requirement for ATP demonstrates the specificity of the interaction between cpn60 and the active moiety; cpn10 is thus the molecular entity initiating response in the EPF bioassay.
Identification of EPF as a cpn10 has been a major step forward in research on this subject and helps to explain many of the findings that have been made to date. Criticism has been raised against claims that EPF production occurs in such a wide variety of biological situations e.g. pre- and post-implantation pregnancy, primary and tumour cell proliferation and platelet activation. In its role as a hsp (heat stress protein) following the advent of the present invention, these are all conditions in which the rapid onset of EPF production would now be expected. Functions of hsp's that are vital to the survival of cells are intracellular as shown in the Linquist et al. reference above. In contrast, the activity of EPF described to date is extracellular; for example, it appears in serum of mice within 4 to 6 hours after mating as discussed in Morton et al., 1987, Current Topics in Development Biology, Vol 23 73-92 and 4 to 8 hours after partial hepatectomy in rats as shown in the Quinn PhD thesis (1991), available from the Biological Sciences Library, University of Queensland Australia, catalogued under both author and title. We have shown that EPF can act in an autocrine mode as discussed in the Quinn et al., 1990 reference referred to above or exocrine mode as discussed in the Rolfe et al. 1988 referred to above; these are not roles previously described for hsp's.
It will also be appreciated that since the structure of EPF is now known, it can be produced in commercial quantities by any suitable technique of recombinant DNA technology.
(b) Cloning of Human cDNA Encoding cpn10 and Production of cpn10
Production for commercial use may be obtained by inserting a mammalian cpn10 gene, preferably a human cDNA cpn10 gene, into a suitable vector such as plasmids from the pGEX system, and pET system expressing the encoded mammalian cpn10 and purifying the recombinant cpn10.
______________________________________Abbreviations______________________________________ANGIS Australian National Genomic Information Servicebp base pairBSA bovine serum albumincDNA complementary DNAcpn 10 Chaperonin 10DNA deoxyribonucleic acidE. coli Escherichia coliGSH glutathione (reduced form)GST glutathione-S-transferaseLB Luria-Bertani BrothM MolarORF open reading framePCR polymerase chain reactionrEPF recombinant Early Pregnancy FactorRSP reverse sequencing primerSDS sodium dodecyl sulphateSDS-PAGE sodium dodecyl sulphate-polyacrylamide gel electrophoresisTris Tris(hydroxymethyl)aminomethaneUSP universal sequencing primer______________________________________
Cloning of Human cpn10 Open Reading Frame
Polymerase chain reaction (PCR) was used to initially amplify part of the ORF (274 bp) of the human cpn10 cDNA from a melanoma cell line A2058 cDNA lambda library (Stratagene). A degenerate cpn10 amplimer (P1) was designed from the amino acid sequence VLDDKDYFL (SEQ ID NO:1) corresponding to amino acid residues 83-91 of human cpn10. The primer P1 has the sequence 5' ARRAARTARTCYTTRTCRTC 3' (SEQ ID NO:2) where R is A or G and Y is C or T. The reverse sequencing primer (RSP) was used for PCR amplification (the non-specific primer) as well as for sequencing DNA constructs and has the sequence 5' CAGGAAACAGCTATGAC 3' (SEQ ID NO:3). The universal sequencing printer has the sequence 5' GTAAAACGACGGCCAGT 3' (SEQ ID NO:4). PCR amplification of the phage library was achieved using a non-specific upstream amplimer (RSP) and P1, each at 0.5 μM final concentration, 1.5 mM MgCl 2 (Pharmacia Biotech), 1 × polymerase buffer (Boehringer Mannheim) and 5 units of Thermus aquaticus DNA polymerase (Boehringer Mannheim) in a final volume of 50 μL. For 30 cycles, the parameters were: denaturation at 94° C. for 1 min. annealing at 40° C. for 30 sec and extension at 72° C for 3 min. A final extension at 72° C. for 7 min was followed by a soak cycle at 4° C. for 10 min. An aliquot of 1 μL was reamplified under the same conditions to increase the cop) number.
Two cpn10 specific amplimers encompassing the open reading frame were designed. The upstream primer P2, 5'-GCGCGGATCCATGGCAGGACAAGCGTTTAG-3' (SEQ ID NO:5) was designed from the sequence of the initial PCR fragment. The downstream primer P3, 5' ATATGAATTCAGTCTACGTACTTTCC-3' (SEQ ID NO:6) was designed from sequence obtained from the Expressed Sequence Tag database via ANGIS (Accession No. HUM00TB037). A 319 bp fragment was amplified from the phage library using the same reaction and cycling conditions as above except the annealing temperature was 50° C.
DNA Constructs and Analysis
All restriction enzyme digests of PCR products and vectors were performed according to Sambrook et al. (Sambrook et al., 1989, Molecular Cloning: A Laboratory Manual. 2nd Ed. Cold Spring Harbor Press, Cold Spring Harbor, N.Y.) using restriction enzymes and their buffers obtained from Boehringer Mannheim. The initial PCR fragment was digested with Eco R1 and ligated (Sambrook et al., 1989, Molecular Cloning: A Laboratory Manual. 2nd Ed. Cold Spring Harbor Press, Cold Spring Harbor, N.Y.) into the Eco RI and Sina I sites of pBluescript KS(+) (Stratagene) creating the plasmid pRMI (FIG. 4: partial cpn10 insert 274 bp). The 319 bp product was digested with Bam HI and ECo RI and initially cloned into the expression plasmid pGEX-2T (Pharmacia Biotech) creating the plasmid pRM2 (FIG. 5). To confirm its identity, the Bum HI-Eco R1 fragment was subcloned into pBluescript (SK+) (pRM3; FIG. 6) and sequenced. DNA was analysed on 0.8-1.0% (w/v) agarose gels containing ethidium bromide and after electrophoresis was viewed under UV illumination.
Transformation of E. Coli
Competent E. coil DH5α cells (100 μL ) were transformed with the plasmids by the heat pulse method (Sambrook et al., 1989, Molecular Cloning: A Laboratory Manual. 2nd Ed. Cold Spring Harbor Press, Cold Spring Harbor, N.Y). The mixture of cells and DNA (10-100 ng) was placed on ice for 30 min and heat pulsed for exactly 2 min at 42° C. and placed back on ice for 2 min. The cells were allowed to recover at 37° C. with shaking for 1 hr after the addition of 0.9 mL of LB. A 100 μL aliquot was plated onto LB agar plates supplemented with Ampicillin at a final concentration of 100 μg/mL. After incubation overnight at 37° C. random colonies were selected for further investigation.
DNA Sequence Determination
Restriction fragments of the PCR products were cloned into pBluescript and sequenced in both orientations by the dideoxy chain-termination method using the T7 Polymerase Kit according to the manufacturer's instructions (Pharmacia Biotech). Approximately 2 μg of plasmid DNA was denatured, ethanol precipitated and annealed to either the USP, RSP or P3. The sequencing reactions were electrophoresed on a 8% acrylamide/46/% urea gel. After fixing and drying, X-ray film was exposed to the gel overnight and developed.
Expression and Purification of recombinant cpn10 E. coli
Clones transformed with pRM2 were screened for expression of the Glutathione-S-transferase fusion protein on a small culture scale (2 ml) according to methods described by Smith et al. (Smith et al., 1988, Gene 67 (1) 31-40). An overnight culture was diluted, induced to express the fusion protein by the addition of IPTG to 0. mM and grown at 37° C. for several hours. The cells were pelleted, lysed in PBS/0.1% Triton X-100 and the lysate mixed with 50% Glutathione-Agarose beads (Sigma Chemical Company). The recombinant fusion protein was eluted from the affinity beads by boiling in SDS loading buffer. An aliquot of the sample was run on a 10% SDS-PAGE gel. The gel was fixed and then stained with Coomassie blue. After confirming the expression of the fusion protein the purification of rcpn10 from the GST moiety was undertaken on a larger scale.
Cells were grown and induced as above, the cell pellet resuspended in PBS, sonicated (output level 4, 50% duty cycle, 2×30 sec) and the cell lysate stored at -30° C. Lysate from 10 liter cell culture was thawed and rcpn10 isolated by similar techniques to those used by Gearing et al. (Gearing et al., 1989, Biotechnology 7 1157-1161) for isolation of rLIF. Briefly, TRITON X-100, a non-ionic surfactant; was added to a final concentration of 0.1% and cellular debris removed by centrifugation (15 min, 15000 rpm, 4° C.). Ten ml glutathione-SEPHAROSE, cross linked agarose beads 4 gel (Pharmacia - LKB Biotechnlogy) was added to the supernatant and the slurry mixed for 2 hr, 4° C. The gel was pelleted, washed × 5 with 50 ml PBS/0.1% Triton X-100 once with 50 ml 0.05 M Tris-HCl pH 8.0/0.15 M NaCl and once with 0.05M Tris-HCl pH 8.0/0.15 M NaCl/2.5 mM CaCl 2 . The gel was resuspended in 4 ml of 0.05 M Tris-HCl pH 8.0/0.15 M NaCl/2.5 mM CaCl 2 buffer, 1000 units thrombin (Sigma T6884) added and the slurry was mixed in a shaking waterbath for 1 hr, 37° C. The gel was pelleted, the supernatant retained, and the gel was then washed with 3×4 ml 0.05 M Tris-HCl pH 8.0/0.15 M NaCl. These washes and the first supernatant, which contain the rcpn10, were pooled, yielding 4-5 mg recombinant protein. Additional rcpn10, which was non-specifically bound to the gel, was recovered as follows. Four ml 0.05 M Tris-HCl pH 8.0/2 M NaCl was added and the slurry mixed for 2 hr, 4° C.
After pelleting, the gel was washed with 3×2 ml of this 0.05 M Tris-HCl pH 8.0/2 M NaCl buffer, the washes pooled with the first supernatant, yielding a further approximately 1 mg rcpn10. Protein concentrations were estimated by the method of Lowry et al. (Lowry et al., 1951, J. Biol. Chem. 193 265-275); proteins were analysed by SDS-PAGE using 15% Tris-Tricine gels (Schagger et al., 1987, Anal. Biochem. 166 368-379).
The recombinant cpn10 has two additional amino acids at the N terminus. The N terminus of the recombinant protein is Gly-Ser-Methionine-Ala whereas the N-terminus of native protein is Ac-Ala. The amino acid sequence of the recombinant cpn10 is as follows: GSMAGQAFRKFLPLFDRVLVERSAAETVTKGGIMLPEKSQGKVLQATVVA VGSGSKGKGGEIQPVSVKVGDKVLLPEYGGTKVVLDDKDYFLFRDGDILGKYVD (SEQ ID NO:9)
2. Application of Mammalian cpn10 16
(a) Assay for cpn10
Antigen
A bacterial fusion protein, GST/cpn10, was expressed and isolated with glutathione-Sepharose, as described for preparation of cpn10. The fusion protein was eluted from the gel by application of 50 mM reduced glutathione in Tris-buffered saline. Eluted fractions were analysed by SDS-PAGE and those containing the most fusion protein were pooled. Protein concentration was determined by the method of Lowry et al., 1951, J. Biol. Chem. 193 265-275.
Antibody
Antibodies against the fusion protein were raised in rabbits using an immunisation schedule consisting of 4× weekly injections followed by at least 4× monthly boosts. Approximately 10 pg protein, emulsified in Freund's Complete Adjuvant for the first injection and in Incomplete Adjuvant thereafter, was used for each injection. Rabbit serum was screened for anti-cpn10 antibodies by ELISA using plates coated initially with cpn10 (5 μg/ml) and a streptavidin-biotin detection system (Amersham). The antibody (Ab) titres against cpn10 and against the whole fusion protein (in this case GST/cpn10, 5 μg/ml, was bound to the plate) in serum of rabbit #42 are shown in FIG. 7. Titration of a serum sample against cpn10, taken from this rabbit after the 4th booster dose, is illustrated in FIG. 8.
Immunoassay
This antibody was then used in a competitive binding assay for detection of cpn10, performed as follows. Anti-serum, diluted 1:32000 and 1:64000 (final dilution: diluent 50 mM sodium phosphate buffer, pH 7.4, containing 0.2% w/v zelatin) %was incubated, separately (overnight, 4° C.) with various concentrations of cpn10. These mixtures were then tested by ELISA as described above, in plates coated with 5 μg/ml cpn10, as illustrated in FIG. 9. Absorbance values for each antibody/cpn10 mixture are compared with values obtained for the same antibody dilution incubated without cpn10. The degree of inhibition of binding of antibody to the plate is proportional to the amount of cpn10 in the original antibody-cpn10 mixture; from this, a standard curve can be constructed, as shown in FIG. 10.
While rabbit #42 is not sensitive enough to detect the very low concentration of cpn10 present in serum, we have established techniques which can:
(1) produce an anti-cpn10 antibody which displays normal hyperimmunisation properties: thus with known techniques for enhancement of the immune response, an antibody with greater avidity could be produced, and
(2) produce a response in a standard immunoassay technique.
With improved antibodies, application of known methods for enhancement of the detection system and pretreatment of serum to both concentrate and partially purify cpn10 (e.g. by application to CI 18 Sep-pak cartridge [Waters] and elution with 80% acetonitrile in Tris-buffered saline, or to immobilised cpn60 in the presence of ATP and elution with EDTA), this technique, alone or in combination with other immunoassay techniques, could be developed for detection of cpn10 in serum.
Sensitivity of the Rosette Inhibition Test, the EPF Bioassay
The rosette inhibition test is non-quantitative and cannot be used to determine the cpn10 concentration in serum with accuracy. The assay may be used semi-quantitatively by comparing the limiting dose of samples, i.e. the highest dilution of sample giving a position response in the bioassay. Caution must be exercised with this approach since other substances in complex biological fluids, themselves inactive in the bioassay, can influence the response of active materials.
We have determined that the bioassay can detect as little as 5 -50 μm/ml pure cpn10 (Cavanagh et a/l., 1994, Eur. J. Biochem. 202 551-560). Based on the observed limiting dose of serum from pregnant women (known inhibitory substances having been removed from early pregnancy serum) and tumour-bearing animals and individuals as well as from rats 24 hr post-partial hepatectomy, the cpn10 concentration of serum is likely to be in the range 0.1-100 pg/ml.
Treatment with cpn10
(a) Organ/Skin Grafts
The Effect of Recombinant cpn10 on The Survival of Allogenic Skin Grafts In Rats
Skin grafting
Skin grafts were exchanged between inbred Lewis and DA rats (˜100 g) using the following protocol. Abdominal full thickness skin was sutured onto a similar sized defect created on the lateral thoracic region using standard techniques. A group of six rats were grafted in one session, with each rat receiving one autograft and one allograft. Two Lewis and 2 DA rats received daily × 2 injections of recombinant cpn10 and one Lewis and one DA received buffer, injected around the site of the grafts. Different groups received different doses of cpn10. Injections were continued for 14 days. The grafts were covered with Vaseline gauze, Melolin dressing, plastic wrap and Co-flex elastic bandage. After 7 days, the grafts were examined daily for signs of necrosis. The day of rejection was taken as that on which 50% of the transplanted skin had undergone necrotic degradation.
Life Span of cpn10 Activity In Serum Following Injection of Recombinant cpn10 into Mice
Various doses of recombinant cpn10 (see FIG. 11) were injected i.p. into BALB/c mice (˜20 g) and the mice bled at various times after administration, commencing at 15 minutes (zero time). Serum was tested for cpn10 activity in the rosette inhibition test (see Morton et al., 1987, Current Topics in Developmental Biology 23 73-92) with spleen cells from C57BL/6 mice. Mice receiving platelet cpn10 were tested in parallel. The half life of cpn10 activity in serum was determined.
Results
The results are shown in TABLE 2 and FIG. 11
There was a significant prolongation of graft survival time following injection of recombinant cpn10 (p <0.001, Student's t test). The results showed a bell-shaped dose response curve, with the most effective doses being in the range of 2 to 20 μg cpn10×2/rat/day. The experiments in mice suggest that this recombinant cpn10 has a shorter than expected half life in serum, when compared with platelet cpn10; the half life of 1 μg and 15 μg recombinant cpn10 in serum of mice was only 3 hours and 7 hours respectively, compared with platelet cpn10 (5 μg), which had a half life of 4 days. However, these results have shown that cpn10 can significantly prolong the viability of allogenic skin grafts in rats. (See TABLE 2).
(b) Treatment of Mammals Including Humans With cpn10 To Promote Wound Healing
The Involvement of cpn10 In Tissue Repair
Growth factors are likely to be involved in the healing process,as their initial release from platelets is of fundamental importance in wound repair (Falange, 1993, J. Dermatol. Surg. Oncol. 19 716-720). Platelets have been shown to be a rich source of cpn10 (cpn10; Cavanagh et al., 1994, Eur. J. Biochem 222 551-560) and therefore may be one of the growth factors intimately involved in wound healing. Studies have been carried out to determine the effect of topically-applied recombinant cpn10 (rcpn10) on the healing of full-thickness skin defects created in mice.
Methods
Outbred, male Quackenbush mice (aged 8 weeks) were anaesthetized with Nembutal, shaved, skin sterilized with 70% v/v ethyl alcohol and a full thickness defect (8 mm diameter) created in the lateral thoracic region. One μg rcpn10 in 5 μl Tris-buffered 0.9% w/v sodium chloride (saline) pH 7.4, Tris-buffered saline alone (5 μl) or saline alone (5 μl) was applied directly to the wound, which was then covered with Vaseline gauze, Melolin non-adherent dressing and held in place with Co-flex elastic bandage. Twice daily, the mice were lightly anaesthetized with halothane (Fluothane, ICI), the dressings removed, 5 μl of the appropriate solution applied and the wound redressed. At various intervals, i.e. 24 hr, 48 hr, 3 d, 4 d, 5 d, 6 d and 7 d, groups of mice were euthanased with halothane, the would and surrounding tissue removed and the area of the wound measured.
Results
Following treatment with rcpn10, there was a significant accceleration of wound contraction, when compared with wounds treated with buffer or saline (FIG. 12). In the wounds treated with cpn10, wound contraction commenced within the first 24 hrs, whereas the control wounds, contraction commenced after 2 days (FIG. 12). From 3 days, there was no significant difference in wound size.
Conclusions
Cpn10 applied topically to full thickness wounds in mice, accelerates contraction and healing, with the process appearing to commence directly after wounding. Wound contraction in the control mice did not become evident until at least 48 hrs later.
Normally, wound healing takes place in three phases. Phase 1, the inflammatory phase (0-48 hrs), begins immediately after injury and is the time during which activated platelets secrete growth factors into the defect, facilitating fibroblast activation and increasing the activity of cells, e.g. macrophages, involved in the subsequent stages of wound healing. Phase 2, the proliferative phase (2-6 days), begins as the first fibroblasts appear and epidermal cells multiply and migrate to the wound site. Phase 3 is the maturation phase.
Wound contraction does not normally commence in phase 1, also known as the lag phase. During this phase, the shape and size of the excised wound is influenced by elastic forces in the neighbouring skin. These forces increase the initial size of the defect and give it a different shape corresponding to the tension lines present in the skin. As we have shown in the groups of mice treated with buffer or saline, the wounds were enlarged during the first 48 hrs. In contrast, the wounds in mice treated with rcpn10 contracted during this time suggesting that administration of rcpn10 directly to the wound accelerated migration of fibroblasts and deposition of collagen to the wound area. This finding will have enormous significance in the treatment of wounds including bums, as accelerated would contraction will greatly decrease fluid loss and risk of infection.
(c) Autoimmune Disease
The Effect of cpn10 On The Development of Experimental Allergic Encephalomyelitis In Rats, An Animal Model of Autoimmune Disease
Introduction
Experimental allergic encephalomyelitis (EAE) is an autoimmune demyelinating disease of the nervous system, induced by inoculation of animals with central nervous system myelin basic protein (MBP) in adjuvant, and widely studied as an animal model of multiple sclerosis (Raine, 1984, Laboratory Investigation 50 608-635). The clinical features of EAE in the rat, a commonly studied species, are dramatic overnight weight loss from day 10 after inoculation, followed by tail weakness and paralysis, hindlimb weakness and sometimes paralysis. Forelimb weakness and paralysis sometimes occur (Pender. 1986, Journal of Neurological Sciences 75 317-328). Experiments were undertaken to determine if administration of rcpn10 to rats following inoculation, would influence progress of the disease.
Methods
EAE Model
EAE was induced in inbred female Lewis rats (aged ˜10 weeks) following inoculation with MBP in Freund's adjuvant into one footpad. Three groups of rats were included in the study. All were inoculated on day 0. Group 1 (n=4) received no treatment and animals were not handled during the incubation period of the disease (day 0 to day 8). Group 2 (Control group; n=5) received Tris-buffered saline (0.1 ml) i.p.×2 daily from day 0 to day 20. Group 3 (Test group; n=5) received 15 ug rcpn10 in Tris-buffered saline (0.1 ml) i.p.×2 daily from day 0 to day 20. From day 8, all rats were weighed and examined daily for 30 days.
(I) Tail weakness was graded as follows:-
0=no weakness;
1=weakness of distal part of the tail only, the distal tail failing to curl round the examiner's finger;
2=weakness of the whole tail but the proximal tail still being able to be erected vertically against gravity:
3=severe weakness with only a flicker of tail movement;
4=complete flaccid paralysis of the tail.
(II) Hindlimb weakness was graded thus:
0=no weakness;
1=slight dragging of the toes of both hindfeet;
2=severe dragging of both hindfeet but not of the rest of the hindlimbs;
3=severe dragging of both hindlimbs, often with both hindlimbs displaced to one side of the body;
4=total flaccid paralysis of the hindlimbs.
(III) The forelimbs were assessed in a similar way to the hindlimbs.
Total score was the sum of the scores in (I). (II) and (III).
Result
The time of onset of weight loss and period of maximum weight loss in the groups receiving no treatment or receiving injections of buffer alone (Control group) did not differ significantly (Table 3). However, initial weight loss was delayed in the group receiving cpn10 (Test group), compared with the group receiving no treatment, as also was the period of maximum weight loss (Table 3; p<0.001 χ 2 distribution). There was no significant difference between the means of maximum weight loss in the three groups (Table 3).
Administration of i.p. injections 2 × daily to the rats with the necessary handling involved did not affect the time of onset or the severity of the disease but did prolong the course of the disease for several days (day 17 to day 18 as shown in FIG. 13). However, one marked difference between these two groups was the recurrence of severe disease in the Control group at day 22, persisting until day 30. In the group receiving no treatment, mild disease only recurred in 3 rats on days 27 and 28.
As with early weight loss, weakness and paralysis of the tail and limbs were delayed in the Test group, receiving rcpn10, compared with the Control group (FIG. 14: day 12, p<0.01: day 13, p<0.05, Heteroscedastic t test). In the Test group over the period from 14 to 16 days, only one rat developed severe disease, similar to that developed by the Control rats. The remaining 4 rats only developed mild disease during this period (FIG. 15, p<0.95, Heteroscedastic t test). Severe disease did not recur in the Test group, during the examination period; one rat developed mild disease at day 22 and the remaining rats from day 27 to day 30.
Conclusions
Treatment itself, i.e. administering fluid i.p.×2 daily to rats, did not effect the onset or severity of the disease but did marginally extend its time course. Furthermore, severe disease did recur during the observation period in the rats receiving daily injections of Tris-buffered saline but not in the rats receiving no treatment.
The most interesting observation made in the this study, was that treatment of the rats with cpn10 did significantly delay the onset and modify the clinical features of the disease in 4 out of 5 rats. It also prevented the recurrence of severe disease during the time these animals were under observation.
(d) Infertility and Miscarriage
A further aspect of the invention is the treatment of fertility and/or miscarriages with the administration of cpn10. This is of importance where the problem arises from the lack of cpn10. Experimental support below demonstrates the requirement for cpn10 during embryo development.
To create the situation of reduced cpn10 concentration, anti-cpn10 antibodies were developed and used. There is no animal model system available. It follows therefore from the experimental support that administration of cpn10 to increase the concentration of cpn10 during pregnancy will overcome the aforementioned problems of infertility and miscarriage.
Synthesis of cpn10 Derived Peptides
Peptides were synthesized to correspond with an N-terminal fragment (N-peptide i.e. Ac-AGQAFRKFLPLC) and an internal fragment (I-peptide i.e. EKSQGKVLQATC SEQ ID NO:8) of cpn10.
Conjugation of Peptides to Ovalbumin
Peptides were conjugated to ovalbumin by the hetero-bifunctional reagent SPDP, following manufacturer's instructions (Pharmacia-LKB Biotechnolkog, Uppsala, Sweden).
Immunisation Schedules
Adult outbred New Zealand rabbits were immunised with one of the conjugates in 4 × weekly injections followed by several monthly boosts.
For injection, the antigen was dialysed into 0.9% saline (Mr 12-15000 cut off dialysis tubing, Visking, Union Carbide, IL, USA) and emulsified with an equal volume of Freund's adjuvant (complete for the first injection, incomplete thereafter). Immunisations were via the s.c. route.
Screening of Anti-Serum
Antisera were tested in an ELISA against the relevant antigens (viz. I-peptide or N-peptide; ovalbumin) (5 mg/ml). Bound IgG was detected by the biotin-streptavidin system (Amersham) with o-phenylene diamine as substrate. Absorbance %%as read at 492 nm.
IgG was precipitated from anti-serum by 45% ammonium sulphate and the concentration determined by Lowry and gel electrophoresis. The IgG preparations were tested in an ELISA (Table 4) against the immunising peptide, conjugated to bovine serum albumin. The preparations were also tested for their ability to neutralise activity of mouse pregnancy serum in the rosette inhibition test. Various concentrations of antibody were incubated with an equal volume of serum, then the mixtures tested for activity in the rosette inhibition test. The lowest concentration of antibody that could completely neutralise activity was determined (see Cavanagh et al., 1994, Eur. J. Biochem. 222 551-560). Ten pg of anti-N-peptide Ab neutralised the activity of 1 ml pregnancy serum while 4 ng anti-I-peptide Ab was needed for complete neutralisation.
Passive Immunisation
Mature outbred male and female Quackenbush mice were caged in pairs at 7.30 a.m. and separated at 8.30 a.m. Female mice with vaginal plugs were injected with anti-N-peptide/ovalbumin, anti-I-peptide/ovalbumin or anti-ovalbumin lgG preparations at 9.00 a.m. and 5.00 p.m. on days 1 (day of mating) and 2 of pregnancy. The dose of specific IgG injected in the 2 dose regimen was estimated as approximately 1 mg/mouse/day. On day 7, mice were euthanased with CO 2 , uteri examined for implanted embryos and the number of corpora lutea (CL) counted. In each group, the number of embryos/CL in the mice treated with the test IgG was compared with the number receiving the same dose of control IgG (χ 2 test).
Results
The results, shown in Table 5 clearly demonstrate that neutralisation of cpn10 in pregnancy serum can adversely affect embryonic viability in the early stages of pregnancy. The ability of antibodies to neutralise activity in the rosette inhibition test is an in vitro monitor of their ability in vivo to adversely affect pregnancy.
Other Aspects of The Invention
In another aspect of the invention, further work has now elucidated two regions of the molecule with biological activity, corresponding with residues 1-11 and 34-44 in rat and human cpn10.
A peptide having the amino acid sequence Ac-AGQAFRKFLPL (SEQ ID NO:10) as well as a peptide having the sequence EKSQGKVLQAT (SEQ ID NO:11)have been found to be active in the rosette inhibition assay. Antibodies raised against both of these peptides are active as antagonists of cpn10 as described in detail in International Application PCT/AU94/00742 (WO95/15339). Both these peptides are prepared synthetically.
The invention therefore includes within its scope amino acid sequences: -
(i) AGQAFRKFLPL (SEQ ID NO:12);
(ii) Ac-AGQAFRKFLPL (SEQ ID NO:10) where Ac is acetyl;
(iii) EKSQGKVLQAT (SEQ ID NO:11) which may function as active centres of the cpn 10 molecule.
The invention also includes within its scope molecules (i), (ii) and (iii) having one or more end sequences A 1 and A 2 ie.
(iv) A 1 AGQAFRKFLPLA 2 ;(SEQ ID NO:13)
(v) AGQAFRKFLPLA 2 ; (SEQ ID NO:14)
(vi) A 1 AGQAFRKFLPL; (SEQ ID NO:15)
(vii) Ac-A 1 AGQAFRKFLPLA 2 ; (SEQ ID NO:16)
(viii) Ac-AGQAFRKFLPLA 2 ; (SEQ ID NO:12)
(ix) Ac-A 1 AGQAFRKFLPL; (SEQ ID NO:18)
(x) A 1 EKSQGKVLQATA 2 ; (SEQ ID NO:19)
(xi) EKSQGKVLQATA 2 ; (SEQ ID NO:20)
(xii) AIEKSQGKVLQAT; (SEQ ID NO:21)
wherein A 1 and A 2 are amino acid sequences which may be added to one or each end of molecules (i) through (xii) and wherein Ac is acetyl.
In the above molecules (i) through (xii), it will be appreciated such molecules also include within their scope a single amino acid addition, deletion or substitution.
In regard to the use of cpn10 in regard to treatment of autoimmune disease, relevant diseases that may be treated by administration of cpn10 include insulin dependent diabetes mellitus, rheumatoid arthritis, systemic lupus erythematosis, Sjogren's syndrome, Graves disease and multiple sclerosis. This is evident from the relevant supporting data in regard to the EAE rat model provided herein.
In relation to the use of cpn10 in relation to treatment of organ transplants, skin grafts, the relevant supporting data given herein refers to the rat skin graft model described herein.
In relation to the use of cpn10 in relation to infertility treatment or prevention of miscarriage, the relevant supporting data refer to the effect of cpn10 antibody on embryonic development and implantation in mice.
In relation to the use of cpn10 in relation to wound healing and tissue repair or regeneration of tissue, this means that cpn10 can be used in treatment of burns, surgery, trauma, skin ulcers including bed sore and diabetic ulcers, infectious diseases involving tissue and organ damage (e.g. hepatitis), metabolic disease involving tissues and organ damage (e.g. liver cirrhosis) and degenerative disease involving tissue or organ damage. The support for these conclusions is given in the mouse wound model referred to herein and the liver regeneration data after partial hepactectomy in rats discussed in Quinn et al., 1994, Hepatology 20 No 5 1294-1302.
The data referred to herein also provides clear support for the use of cpn10 in treatment of inflammatory conditions including inflammatory bowel disease and infectious disease. Such data as described herein includes references drawn from the immunosuppressive effect of cpn10 in the rat EAE and skin graft models. This is also supported by Rolfe et al., 1983, Clin. exp. Immunol. 51 45-52 and Nature 278 No. 5705 649-651 showing that EPF can reduce delayed type hypersensitivity in mice.
The use of cpn10 in treatment of allergic disease including allergic rhinitis, asthma, atopic dermatitis, acute urticaria and drug hypersensitivity is also fully supported by the immunosuppressive effect of cpn10 in the rat EAE and skin graft models. This conclusion can also be drawn from Rolfe et al., 1983, Clin. exp. Immunol. 51 45-52 and Noonan et al., 1979, Nature 278 No. 5705 649-651 showing effect of EPF in reducing delayed type hypersensitivity in mice.
The use of cpn10 in relation to diagnosis of tumours and/or monitoring patients after surgical removal of tumours is supported by the reference Quinn et al., 1992, Cancer Immunol. Immunother. 34 265-271.
In regard to dosages that may be employed concerning administration of cpn10, a convenient dosage would be of the order of 1-1000 μg/kg of body weight and more preferably 50-200 μg/kg of body weight.
TABLE 1______________________________________ Limiting Dose (log reciprocal)Sample Untreated + 5/341______________________________________Human platelet EPF 13 <2(50 μg/ml)Rat liver cpn 10 (50 13 <2μg/ml)E. coli cpn 10 (groES) NA NT(50 μg/ml)______________________________________
TABLE 2______________________________________TREATMENT SKIN GRAFT SURVIVAL TIMErEPF/cpn 10 (dose Lewis → DA DA → Lewisx 2/rat/day) Days ± SD (n) Days ± SD (N)______________________________________buffer alone 8.7 ± 0.75 (7) 9.1 ± 0.83 (8) .sup. 1 μg -- 9.0 ± 1.0 (3) (NS) 5 μg 14.0 ± 1.6 (4)* 14.5 (2)20 μg 15.2 ± 0.92 (4)* 12.5 (2)70 μg 10.0 (2) 11.0 (2)______________________________________
TABLE 3______________________________________ Max. Max. Onset period weight of of loss weight weight (% wt.Treatment loss loss atGroup n (day) (day) p' d 10) p*______________________________________No 4 11 14-16 15.4treatmentBuffer 5 11 15-17 NS 13.9 NS(Control)cpn 10 5 12-14 17-19 p < 13.9 NS(Test) 0.001______________________________________
TABLE 4______________________________________ Titre (reciprocal serum dilutionAntibodies (mg/ml) N-peptide (5 μg/ml) I-peptide (5 μg/ml)______________________________________Anti-N-peptide 128000 <1000*Anti-I-peptide <1000* 32000Anti-ovalbumin <1000* <1000*______________________________________
TABLE 5______________________________________Antibody No. of Corpora(total dose animals lutea/mouse2 in (mean ± Embryo/mousemg/mouse) group sem) (mean ± sem) p*______________________________________Anti-N- 6 19.1 ± 1.2 10.6 ± 3.8 <peptide- 0.05ovalbuminAnti-I- 6 20.8 ± 0.8 17.1 ± 1.1 <peptide- 0.02ovalbuminAnti- 5 17.8 ± 1.0 16.8 ± 0.5 NSovalbumin______________________________________
TABLE LEGENDS
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#e Leu Pro Leu Phe Asp# 15- Arg Val Leu Val Glu Arg Ser Ala Ala Glu Th - #r Val Thr Lys Gly Gly# 30- Ile Met Leu Pro Glu Lys Ser Gln Gly Lys Va - #l Leu Gln Ala Thr Val# 45- Val Ala Val Gly Ser Gly Ser Lys Gly Lys Gl - #y Gly Glu Ile Gln Pro# 60- Val Ser Val Lys Val Gly Asp Lys Val Leu Le - #u Pro Glu Tyr Gly Gly#80- Thr Lys Val Val Leu Asp Asp Lys Asp Tyr Ph - #e Leu Phe Arg Asp Gly# 95- Asp Ile Leu Gly Lys Tyr Val Asp 100- (2) INFORMATION FOR SEQ ID NO:8:- (i) SEQUENCE CHARACTERISTICS:#acids (A) LENGTH: 13 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:- Xaa Ala Gly Gln Ala Phe Arg Lys Phe Leu Pr - #o Leu Cys# 10- (2) INFORMATION FOR SEQ ID NO:9:- (i) SEQUENCE CHARACTERISTICS:#acids (A) LENGTH: 12 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:- Glu Lys Ser Gln Gly Lys Val Leu Gln Ala Th - #r Cys# 10- (2) INFORMATION FOR SEQ ID NO:10:- (i) SEQUENCE CHARACTERISTICS:#acids (A) LENGTH: 12 amino (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:- Xaa Ala Gly Gln Ala Phe Arg Lys Phe Leu Pr - 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#e (B) LOCATION: 1#/product= "Other"R INFORMATION:#"The Xaa at position 1 is acetyl."- (xi) SEQUENCE DESCRIPTION: SEQ ID NO:25:- Xaa Ala Gln Ala Gly Phe Arg Lys Phe Leu Pr - #o Leu Phe Asp Arg Val# 15- Leu Val Glu Arg Ser Ala Ala Glu Thr Val Th - #r Lys Gly Gly Ile Met# 30- Pro Leu Glu Lys Ser Gln Gly Lys Val Leu Gl - #n Ala Thr Val Val Ala# 45- Val Gly Ser Gly Gly Lys Gly Lys Gly Gly Gl - #u Ile Gln Pro Val Xaa# 60- Xaa Lys Xaa Gly Xaa Xaa Val Leu Leu Pro Gl - #u Tyr Gly Gly Thr Lys#80- Val Val Leu Asp Asp Lys Asp Tyr Phe Leu Ph - #e Arg Asp Gly Asp Ile# 95- Leu Gly Lys Tyr Val Asp 100__________________________________________________________________________ | 4y
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to interconnected processing systems, and more particularly, to processing systems that dynamically control I/O interface performance based on a prediction of I/O requirements.
[0003] 2. Description of Related Art
[0004] Interfaces within and between present-day integrated circuits have increased in operating frequency and width. In particular, in multiprocessing systems, both wide and fast connections are provided between many processing units. Data width directly affects the speed of data transmission between systems components, as does the data rate, which is limited by the maximum frequency that can be supported by an interface. However, such fast and wide interconnects are significant power consumers in a computer system formed from interconnected processing units.
[0005] The processing units in a multi-processing system, particularly a symmetric multi-processing system (SMP) may need to communicate at any time, since, for example, when close affinity is provided between processors, a processor might access memory that is located on a remote node, but that is otherwise available in the processor's memory space. Therefore, for the above and other reasons, present-day multi-processing systems typically keep the physical layer of the interfaces operational and cycle idle data patters on the interconnects in order to maintain calibration of the links when transmissions are not being made over the interface physical layer. However, such operation wastes power, generates heat, and raises background noise levels (electromagnetic emissions) in the system. The alternative of placing the interface physical layers in a power-managed state would lead to unacceptable latency for transactions.
[0006] It is therefore desirable to provide a method, interface and computer system that more effectively manage the state of interface physical link layers in a multi-processing system to reduce power consumption and background noise levels.
BRIEF SUMMARY OF THE INVENTION
[0007] The above-mentioned objective of providing improved performance and/or power efficiency of a system interconnect physical layer between processing units is provided in a method, and a computer system and an interface that implement the method.
[0008] The method is a method of managing the state of a physical link layer of external interfaces that interconnect processing units of a computer system. The physical link layers have dynamically adjustable bandwidth. The method detects events other than I/O requests that occur in a processing unit that are indicators of potential future transactions on one of the external interfaces connected to the processing unit. The method predicts, from the detected events, that future transactions will likely occur on the interface, and in response, controls the dynamically adjustable bandwidth of physical link layer of the interface to accommodate the future transactions by increasing the dynamically adjustable bandwidth of the first physical link layer interface. After the future transactions have occurred, the dynamically adjustable bandwidth of first physical link layer is restored to a lower value.
[0009] The foregoing and other objectives, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiment of the invention, as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0010] The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of the invention when read in conjunction with the accompanying Figures, wherein like reference numerals indicate like components, and:
[0011] FIG. 1 is a block diagram of a computer system in which techniques in accordance with embodiments of the invention are implemented.
[0012] FIG. 2 is a block diagram showing details of a processing unit 10 that can be used to implement processing units 10 A- 10 D of FIG. 1 .
[0013] FIG. 3 is a block diagram of a controller 30 that can be used to implement controller 30 A and/or 30 B within processing unit 10 A of FIGS. 1-2 .
[0014] FIG. 4 is a flowchart showing an exemplary method of operating a processing system.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The present invention encompasses techniques for controlling the bandwidth, including the width and/or frequency of links, such as parallel busses or serial connections, that interconnect processing units in a processing system. Non I/O (input/output) transaction events occurring within the processing units are used to predict when I/O transactions are likely to occur over the links and the prediction is used to control the bandwidth of the links to accommodate the predicted transactions. The techniques thus can reduce power consumption and radiated emissions by maintaining the links in a lower power or inactive state between use.
[0016] With reference now to the figures, and in particular with reference to FIG. 1 a distributed computer system in accordance with an embodiment of the present invention is shown. A first processing unit 10 A includes a processor core 12 coupled to a memory 14 that stores program instructions for execution by processor 12 . The program instructions may include program instructions forming computer program products that perform portions of the techniques disclosed herein within processing units 10 A- 10 D. Processing unit 10 A also includes a network interface (NWI) 16 that couples processing unit 10 A to interface links 11 , which are wired or wireless links to other processing units 10 B, 10 C, and provide for access between processing unit 10 A and resources such as remote memory 14 A within processing unit 10 B. Links 11 have dynamically adjustable bandwidth/power consumption, which is controlled as disclosed below. Other processing units 10 B- 10 D are of identical construction in the exemplary embodiment, but embodiments of the invention may be practiced in asymmetric distributed systems having processing units with differing features. The distributed computer system of FIG. 1 also includes other resources such as I/O devices 19 , including graphical display devices, printers, scanners, keyboards, mice, which may be coupled to the links 11 or one of nodes 10 A- 10 D. Processing units 10 A- 10 D are also coupled to storage devices 18 , for storing and retrieving data and program instructions, such as storing computer program products in accordance with an embodiment of the invention.
[0017] Referring now to FIG. 2 , details within a processing unit 10 that can be used to implement processing units 10 A- 10 D are shown. Within processing unit, controllers 30 A, 30 B are shown to illustrate two possible locations of a controller that manages the bandwidth of a physical link layer 24 of interface 11 according to one or more control signals bw. Within one or more of core 12 , memory 14 and network interface 16 , logic, control logic detects events that are indicative of future external bus transactions that are likely to be issued over interface 11 . For example, a controller 30 A within core 12 might detect that certain instructions are being executed, or memory ranges are being read or written, that correspond to operations that will generate I/O transactions over interface 11 . For example, controller 30 A may detect that a direct-memory access (DMA) buffer is being allocated, or a DMA channel being initialized in bus I/O unit 20 or elsewhere within processing unit 10 for transfer to buffers 21 that supply data to, or receive data from, a logical link layer 22 of network interface 16 . Controller 30 A may be coupled to one or more trace array units 13 within core 12 to capture state information that is indicative of the events, and combine the state contained in the trace array to provide detected events as input for predicting a required bandwidth of interface 11 in the near future. System level events such as a hypervisor executing within processing unit 10 starting a thread with an association to remote memory, or the association of remote memory to a running thread can be used to predict and trigger an increase in link bandwidth between the core on which the thread is running and the location of the remote memory, so that when the inevitable memory accesses by the thread occur, the link is operating at sufficient bandwidth. Similarly, a controller 30 B within arbiter 26 of logical link layer 22 may detected that the logical link layer 22 , and thus interface 11 is being arbitrated for and therefore physical link layer 24 will soon need to be active for a number of transactions. In another example, controller 30 B may count idle cycles of logical link layer 22 to determine a required bandwidth for physical link layer 24 . Alternatively, or in combination, controller 30 B within network interface 16 (whether or not within arbiter 26 ) might also be connected to detect activity in buffers 21 with write operations anticipating upcoming output operations, or initialization of the buffer indicating a future read transaction that will be commanded by core 12 or another actor within processing unit 10 .
[0018] Processing unit 10 of FIG. 2 is used to illustrate control of one of links 11 between two of processing units 10 A- 10 D, but the techniques of the present invention extend to connection of memories, peripherals and other functional units within a computer system or other electronic device and are not to be construed as limiting as to the particular system in which they are implemented. Links 11 between processing units 10 A- 10 D are, in the example, made by a uni-directional physical layer interconnect of wired signals connected between processing units 10 A- 10 D, however, the techniques of the present invention extend to non-physically connected (wireless) interfaces having multiple datapaths and to bi-directional interfaces, as well. In order to support the adjustable bandwidth of links 11 , processing units 10 A- 10 D may include elastic interface (EI) units with adjustable operating frequency and/or selectable width as described in detail in U.S. Pat. No. 8,050,174 entitled “SELF HEALING CHIP-TO-CHIP INTERFACE”, U.S. Pat. No. 7,117,126 entitled “DATA PROCESSING SYSTEM AND METHOD WITH DYNAMIC IDLE FOR TUNABLE INTERFACE CALIBRATION” and in U.S. Pat. No. 7,080,288 entitled “METHOD AND APPARATUS FOR INTERFACE FAILURE SURVIVABILITY USING ERROR CORRECTION.” The disclosures of the above-referenced U.S. Patents are incorporated herein by reference.
[0019] Referring now to FIG. 3 , details of a controller 30 that may be used to detect events and predict future transactions on a physical layer of interface 11 is shown. Controller 30 may, for example, implement controller 30 A within core 12 as shown in FIG. 2 . Controller 30 is also provided only as one example of an architecture that may be implemented in discrete logic, for example as a state machine, or may be implemented in firmware or software as program instructions executed by core 12 or another processor within processing unit 10 , such as a core within logical link layer 22 or a service processor coupled to core 12 . As an example of a mechanism for detecting events, a bus snooper 31 observes transactions on an internal or external bus of core 12 , such as a bus that couples core 12 to memory 14 . In another example a hypervisor 34 reports thread state change or remote memory association events, such as the above-described connection between a thread executing within processing unit 10 and a remote memory. When an event detector 32 A detects that a combination of events indicates a likelihood that a number of transactions will soon occur over interface 11 , a counter 35 A in prediction unit 34 is incremented. Similarly, another event detector 32 B receives indications of activity at logical link layer 22 and determines whether to increment another counter 35 B based on whether the activity indicates that a number of transactions will occur over interface 11 . A bandwidth profile calculator 33 determines from the values of counters 35 A and 35 B, which may be periodically reset, or reset according to another mechanism, the bandwidth that is likely needed over interface 11 . Bandwidth profile calculator 33 provides a control signal to a physical link layer bandwidth control circuit that sets the operating frequency and/or width of the physical link layer of interface 11 appropriately to balance power consumption (or generated noise, etc., depending on the particular system criteria) with the bandwidth supplied over interface 11 for the transactions. A timer 37 is provided to restore the bandwidth to an initial value after a predetermined or programmable interval. In one exemplary implementation, timer 37 controls a time between intervals of full-bandwidth or partial-bandwidth operation as commanded by bandwidth profile calculator 33 and a low-power shutdown state. The width of the intervals can also be set by bandwidth profile calculator, so that interface 11 is cycled between the low-power state and the full-bandwidth or partial-bandwidth state in order to complete transactions that are allowed to accumulate in buffers 21 between the intervals of full-bandwidth or partial-bandwidth operation. In all of the cases above, the actual demand generated by I/O requests is generally combined with the predicted demand to determine an appropriate link bandwidth.
[0020] Referring now to FIG. 4 , a method of operating a processing system is illustrated in a flowchart. First, interface links between processing units are initialized and calibrated at a nominal interface width and frequency (step 50 ). During operation, events are detected that indicate I/O is likely to occur over one or more of the links (step 51 ). The events are logically combined and counter to generate predictors that indicate a bandwidth that will be needed for the one or more links (step 52 ). Once the predictor is over a threshold value (decision 53 ) or the link utilization is over a threshold value (decision 54 ), the bandwidth of the physical layer (PHY) is raised for a predetermined time period (step 55 ). After the predetermined time period has elapsed (decision 56 ) the bandwidth of the physical layer is lowed to the previous bandwidth (step 57 ). Until the scheme is ended or the system is shut down (decision 58 ), steps 51 - 57 are repeated.
[0021] As noted above, portions of the present invention may be embodied in a computer program product, e.g., a program executed processors having program instructions that direct the operations outlined in FIG. 4 , by controlling the interfaces of FIG. 2 and FIG. 3 . The computer program product may include firmware, an image in system memory or another memory/cache, or stored on a fixed or re-writable media such as an optical disc having computer-readable code stored thereon. Any combination of one or more computer readable medium(s) may store a program in accordance with an embodiment of the invention. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
[0022] In the context of the present application, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.
[0023] While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form, and details may be made therein without departing from the spirit and scope of the invention. | 4y
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of writing instruments, namely, ball point, fountain and rollerball pens and mechanical pencils; and more particularly to instruments of these types that are hand made, usually by hobbyists or craftsmen in this field; and this invention deals with specialized tools for assembly and disassembly of such instruments.
2. Prior Art
Applicant is not aware of any pertinent prior art before the development of his method and apparatus as disclosed herein.
U.S. Pat. No. 4,635,338, issued Jan. 13, 1987 to Wm. H. Walsh, relates to a mechanized procedure for assembling of lead into an automatic pencil.
SUMMARY OF THE INVENTION
A primary object of this invention is to provide a method of disassembly of writing instruments of this type, usually having a wooden exterior, on a metal body, without damaging the body or the wood or any of the structural or functional parts of the instrument.
Another object is to provide a simplistic series of tools to be employed in carrying out the method of this invention.
A further object is to provide a multiple part system of tools to be used in the disassembling of a series of pens, pencils and the like, that may be used with a variety of turning kits employed by craftsmen in producing handsome bodied pens from natural or man-made materials; a "turning kit" being the functional parts necessary to make a complete wooden bodied pen or pencil when the wood part of the body has been "turned" on a lathe.
A further object is to provide a multiple part system of tools to be used in the disassembling of a series of pens, pencils and the like, that may be used with a variety of turning kits employed by craftsmen in producing a handsome wood or other material writing instrument.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exterior view of a ball point pen that may be assembled and disassembled using the tools of this invention;
FIG. 2 is an exploded view of the component parts of the ball point pen of FIG. 1;
FIG. 3 is a tool kit comprising the tools to be used in assembling and disassembling the pen of FIG. 1, and similar writing instruments; wherein:
FIG. 3A is the rod tool of FIG. 3;
FIG. 3B is the shaft tool of FIG. 3;
FIG. 3C is a side view of the spreader tool of FIG. 3;
FIG. 3D is an end view of the spreader tool of FIG. 3C;
FIG. 4 is a view of the rod tool of FIG. 3A inserted into a portion of the pen, preparatory to removal of the pen tip;
FIG. 5 is a view of the shaft tool of FIG. 3B inserted into the cap body, preparatory to removal of the clip cap;
FIG. 6 is a partial cross-section view showing a method step in the disassembly process, wherein a mark is placed on the shaft tool of FIG. 3B for future reference;
FIG. 7 is an "X-ray" view of the pen of FIG. 1, showing the assembled parts in place prior to disassembly;
FIG. 8 is an exterior view of a typical automatic/mechanical pencil that may be assembled and disassembled by the process and/or using the tools of this invention;
FIG. 9 is an exploded view of the pencil of FIG. 8, and showing the component parts thereof;
FIG. 10 is an outline view of a portion of the pencil of FIG. 8, and showing alternate keepers that may be employed;
FIG. 10A is an enlarged side view partly in section of the flush keeper of FIG. 10;
FIG. 11 is an outline view of the shaft tool of the pencil tool kit used herein;
FIG. 12 is a view of the tap tool used herein;
FIG. 13 is an outline view of the keeper rod tool used herein;
FIG. 14 is an end view of the keeper point tool of the pencil tool kit of this invention;
FIG. 15 is a side view of the keeper point tool of the pencil tool kit;
FIG. 16 is a side view of the cap screw tool of the pencil tool kit used herein;
FIG. 17 is an enlarged end view of the topmost keeper of FIG. 10;
FIG. 18 is a section view taken at lines 22--22 of the keeper point tool of FIG. 15;
FIG. 19 illustrates the use of the keeper rod tool to insert the keeper point into a mechanical pencil;
FIG. 20 is a sectional view showing the keeper point being inserted if the lower tube of the pencil of FIG. 19;
FIG. 21 is a sectional view of the keeper point fully engaging the keeper shown in FIG. 20;
FIG. 22 is a sectional view of the alternate keeper shown in FIG. 10, prior to its removal from the lower tube of the pencil of FIG. 8;
FIG. 23 is a partial section of the upper tube and clip connector showing the tap tool cutting a thread in the clip connector;
FIG. 24 shows the cap screw tool being threaded into the tapped top of the pencil of FIG. 23, with the keeper rod tool inserted into the other end of the pencil;
FIG. 25 shows the shaft tool inserted into the upper tube of the pencil in preparation for the separation of the upper and lower tubes;
FIG. 26 shows the shaft tool inserted into the lower tube of the pencil in preparation for removal of the middle connector;
FIG. 27 is an outline view of an assembled rollerball pen;
FIG. 28 is an exploded view of the pen of FIG. 27;
FIG. 29 is an outline view of a fountain pen;
FIG. 30 is an exploded view of the pen of FIG. 29;
FIG. 31 is a ball point pen known by the name of "Fat Pen";
FIG. 32 is an exploded view of the pen of FIG. 31;
FIG. 33 is an outline view of the shaft tool used with the pens of FIGS. 27, 29 and 31;
FIG. 34 is the "plug with hole" tool used herein;
FIG. 35 is a thumb screw used with the tools of FIGS. 33 and 34;
FIG. 36 is a view of the main pen body and threaded coupler of the one style of pen referenced herein;
FIG. 37 is a view similar to FIG. 36, of the Rollerball Pen style;
FIG. 38 is an outline view showing a shaft tool in one process step of removal of the end/finale of certain pen styles;
FIG. 39 is an outline view showing the process step of removing a threaded coupler from the pens herein;
FIG. 40 illustrates another process step in removing components from the pens herein described;
FIG. 41 illustrates a process step in the removal of the end/finale component from certain pen bodies;
FIG. 42 illustrates the utilization of the "plug with hole" tool for removing the end/finale of a pen;
FIGS. 43-46 represent other uses of the shaft tool in the disassembly process of this invention.
FIG. 47 is an end view of the pencil cap remover;
FIG. 48 is a side view of the pencil clip remover (PCR) tool of this invention;
FIG. 49 is a side view of the stepped shaft tool used to disassemble certain component parts;
FIG. 50 is an end view of the tool of FIG. 49;
FIG. 51 is a backing plate tool to supplement the action of the tool of FIG. 49.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now more particularly to the characters of reference in the drawing, it will be observed in FIGS. 1 and 2 that the complete ball point pen assembly 1, comprises a pen tip 2 attached to the forward end of pen body 3, which includes a mechanism 4 for holding a refill unit 5, which is partly received in cap body 6 for adjusting the location of the ball point 7 of refill 5. Cap body 6 includes a clip 8 and a clip cap 9 at the upper end of pen 1, and a middle ring 10. Wooden sleeves 3' and 6' are glued to the brass tubes of the pen body 3 and cap body 6 respectively to complete the parts of the pen of this embodiment.
The tool kit, indicated in FIG. 3 and comprising the tools of FIGS. 3A-D, is used for assembly and disassembly of the pen 1. The tool kit comprises a rod 12, a shaft 13, and a spreader 14, each of which are employed in certain steps of the following disassembly method and procedure:
In Step One, the cap body 6, middle ring 10, and refill 5 are all removed from pen assembly 1 and set aside. Refill 5 (a purchased part) unscrews from mechanism 4 via matching threads T as shown in FIG. 2.
Step Two, insert rod 12 into mechanism 4, as if it were refill 5, until it contacts pen tip 2, as shown in FIG. 4.
Step Three, firmly grasp the pen body 3, and with a hammer, tap the exposed end of rod 12 to remove the pen tip 2 (glued tips require a few more taps).
Step Four, insert shaft 13 into open end of cap body 6, as shown in FIG. 5, firmly grasp cap body 6, and hammer tap exposed end of shaft 13 to remove clip cap 9 and clip 8.
Step Five, with pen tip 2 and cap body 6 removed, insert shaft 13 into (former) tip end 15 of the pen body 3, until it engages one end of mechanism 4.
Step Six, insert the other end of mechanism 4 into the tapered end rim 16 and hole 18 of spreader 14, as shown in FIG. 6, making sure that no wood of the pen body sleeve 3' contacts the rim 16 of spreader 14; at this point the shaft 13 should be scribed as noted at 11 in FIG. 6, to provide a "depth gage" for future reference at re-assembly.
Step Seven, place entire sub-assembly 17 of shaft 13, body 3, mechanism 4 and spreader 14, selectively into a vise, as shown in FIG. 8 or into a quick-grip clamp, as shown in FIG. 9, and tighten slowly to press mechanism 4 from pen body 3, through the central opening 18 of spreader 14.
At the appropriate point, if desired, the wood sleeves 3' and 6' that are glued to the brass tubes of the pen body 3 and cap body 6, may be refinished or removed by turning on a lathe, or scraping and making the brass tubes ready to accept new pieces of wood, or other decorative material.
It is essential when using the spreader tool 14, that the pen body 3 contact the circular end portion 16, and that no part of the wooden sleeve 3' touch this rim 16, to prevent cracking or other damage to the wood when removing the mechanism 4.
For reassembly, the following steps are used:
Step One, insert mechanism 4 into pen body 3 using a vise or quick grip, inserting the mechanism deeper into the pen body than the desired working depth; and insert the other end of the mechanism into the tapered end of spreader 14.
Step Two, insert shaft 13 into open end of pen body 3, and place the end of the shaft and the end of the spreader 14 between the jaws of a vise or quick grip. Slowly apply pressure with the vise or quick grip to the end of the shaft 13 and the end of the spreader 14, driving the shaft farther into the pen body 3, thus pushing the mechanism 4 to a desired working depth in the pen body. When the scribed "depth gage" mark 11 on the shaft 13 is at the end of pen body 3, as shown in FIG. 6, stop applying pressure because the mechanism 4 is at the desired working depth. Remove the shaft 13 and other tools from the vise or quick grip and remove the shaft from the pen body 3.
Step Two, insert shaft 13 into open end of pen body 3, until the "depth gage" mark is reached to properly locate mechanism, and then remove shaft 13.
Step Three, insert pen tip 2 into pen body 3, using vise or quick-grip clamp to press pen tip 2 into place in pen body 3.
Step Four, reassemble pen body 3 with mechanism 4 and refill 5 into cap body 6, manually, or with the aid of vise or clamp as noted in Exhibit A.
Step Five, reverse the disassembly process for re-assembling any parts not specifically called out above.
Certain precautions need to be observed when assembling or disassembling writing instruments or this type, namely:
Always wear proper eye protection when using a hammer;
Cover one end of rod 12, and one end of shaft 13, with a piece of tape, and always hammer on the taped ends only;
Do not use hammer directly on tapered end of spreader 14.
Turning now to the disassembly and reassembly of the pencil of FIG. 8, refer to FIGS. 8-26.
FIG. 8 shows the complete pencil 20 to be comprised of a pencil tip 21, a lower body 22, 22', a middle connector 23, an upper or cap body 24, 24', a clip connector 25 and a clip 26. The outer portion of the bodies indicated at 22' and 24' are of a high grade and handsome appearing wood, such as "Dymond" wood or other decorative material that is usually turned on a lathe, and probably accounts for the term "turning kit" that applies to the metal parts of the writing instrument components shown in this specification, that are necessary to build a complete writing instrument.
In the exploded view (FIG. 9) of the pencil 20, the detail components thereof are seen as the pencil tip 21 with a lead guide 27 extending therefrom, an internally located keeper 28, or 28A (shown in phantom in FIG. 10), a pencil mechanism 30 which extends completely thru the lower body tube 22, middle connector 23 and upper or cap body tube 24, until the lead activator and eraser cap 32 projects thru clip connector 25.
The tool kit, used for assembly and disassembly, comprises keeper rod 34, shaft 35, keeper point 36, cap screw 37, and tap 44, each of which tools are employed in the following disassembly method:
In Step One, unscrew the pencil point or tip 21, and remove pencil mechanism 30. The pencil body, or lower tube 22 end has either a flush keeper 28, or an alternate extended keeper 28A as seen in FIG. 10. For the flush keeper 28, insert keeper point 36 into the blind hole 45 of keeper rod 34, and insert rod and point into pencil 20 as seen in FIG. 19, making sure that keeper point 36 extends slightly from the end of the flush keeper 28, as seen in FIG. 21; if not, rotate until the flats 38 on the keeper point 36 align with dimples 39 on the keeper 28, shown in FIGS. 14, 15 and 16.
In Step Two, for the extended type alternate keeper 28A, insert the keeper rod 34 fully into the keeper 28A in the manner indicated in FIG. 22.
In Step Three, grasp the lower tube 22 and hammer tap the exposed end 40 of keeper rod 34 until the keeper point 36 and keeper 28A are removed from the lower tube 22; then remove keeper rod 34.
In Step Four, insert tap tool 44 into the clip connector 25 and, as shown in FIG. 23, using a wrench turn the tap clockwise until approximately 1/2" of thread is visible on the top of tap 44. This action provides a thread 31 on the inside of the clip connector 25.
In Step Five, remove the tap 44 and insert cap screw 37 fully; then insert the keeper rod 34 into the opposite end until it contacts the bottom of the cap screw 37 as shown in FIG. 24, then hammer tap on the exposed end 40 of keeper rod 34 until the clip connector 25 and cap screw 38 are removed from upper tube or cap body 24; then remove the keeper rod 34, and cap screw 37.
An alternate to Steps Four and Five is the use of pencil clip remover (PCR) 41, as shown in FIGS. 47 and 48, insert pencil clip remover into clip connector 25. Turn screw 42 on pencil clip remover 41 to expand the grippers 43 inside of clip connector 25, using keeper rod 34, hammer out clip connector. Unscrew screw on PCR to relax fit of grippers 43 on a ridge (not shown) inside of clip cap 25, and remove PCR 41.
In Step Six, insert shaft 35 into the upper tube 24 as noted in FIG. 25, until it contacts the middle connector 23, then grasp the upper tube 24 and hammer tap on the end 19 of shaft 35 until the upper tube 24 is separated from the middle connector 23.
In Step Seven, insert shaft 35 into the lower tube 22 until it contacts the middle connector 23, as shown in FIG. 26, and then hammer tap the exposed end 19 of shaft 35 until the middle connector 23 is separated from the lower tube 22.
At this point any defective components may be replaced, and the pencil reassembled by basically reversing the foregoing disassembly steps.
Turning now to FIGS. 27-35 of the drawing, the pens known as Rollerball 50, Fountain Pen 51 and Fat Pen 52 are disclosed in outline form respectively in FIGS. 27, 29 and 31. The tools for disassembly of these pens are shown in FIGS. 33-35.
Regardless of which style pen is involved, the concept of disassembling is still the same, and as follows:
Step One, remove the point assembly 55 (including NIB section 55A, if separate), the refill 56 and the spring 57.
Step Two, for styles with double threaded couplers 61, unscrew the end/finale 59 and skip to Step Four.
Step Three, insert shaft tool 60 into the threaded coupler 61, and open end 62 of the main pen body 63, until shaft 60 touches the end/finale 59, as shown in FIG. 38. Grasp the pen body firmly and with a hammer, tap on the end of shaft 60 until the end/finale 59 is removed. Then remove shaft 60.
Step Four, thread the thumb screw 64 (of FIGS. 35 and 39) into the threaded coupler 61 until tight; then insert shaft 60 into other end 66 of the pen body 63; grasp pen body firmly, and hammer tap on end 67 of shaft 60 until the threaded coupler 61 is removed (along with cap screw 64). For styles with double couplers, remove thumb screw 64 from the coupler 61, and repeat this procedure on the remaining coupler, not shown.
Step Five, for pens like shown in FIG. 41, where the end/finale 59 is pressed on instead of screwed on, follow procedure of steps 3 and 4 and, once the threaded coupler is removed, insert plug 69 with hole end 70 making contact with connector 59A, as shown in FIG. 42, grasp the pen body 63 firmly and with hammer, tap the exposed shaft end 67 (after tape applied) until connector 59 is removed.
Step Six, referring to FIGS. 28, 30 and 40, to finish the cap portion 73 of pen 50/51, the white plastic cup piece 75 is removed, and using the tools of kit 53, insert plug 69 so that the hole end 70 covers the threads 77 of clip assembly 9, then insert shaft 60 into the cap body 73; grasp cap body firmly, and with hammer, tap on exposed and wrapped end 67 of shaft 60 until the cap assembly 9 is removed using the procedure shown in FIG. 40.
Step Seven, for pens like that shown in FIG. 41, there is a large gold ring/band which requires the use of stepped shaft tool 90 of FIG. 49 to remove the brass tube component from the gold ring component of Mt. Blanc© and various Parker© style kits.
Due to the nature of the mechanical connection involved with the "gold ring" component this component is usually the hardest to salvage. The steps are so designed that OD and ID of respective kits match. This matching insures transfer of force to brass tube component for removal. Various OD's may apply to the brass tube, material, gold ring component connection, insuring clean break from gold ring component minimizing cleanout.
Backing plate 91 of FIG. 51 is designed to back support the "gold ring" component for removal; holes/slots 93, with access to outer perimeter, of varying diameter allow brass tube component to be slid into place and providing proper area of support. The number of holes/slots and their allowable sizes will be that of known dimensions of today's kits. Enough room on backing plate will allow for future sizes to be added, and may be added by user for user use only. Backing plate thickness may vary, however, optimum thickness will be used to maintain true disassembly performance.
Referring now to FIGS. 21 and 28, the rollerball pen 50 is seen to comprise a main pen body 63, which in this instance is a brass tube having three linear stepped down sections, and a point assembly 55 (including NIB section 55A), that slides into a white plastic cup piece 75 simultaneously with its being seated into cap portion 73. Prior to final assembly (as shown in FIG. 28), a handsome wood cap sleeve 73' and stepped wood sleeve 63' are glued onto and over cap body 73 and pen body 63 respectively. Between pen body 63 and point assembly 55, a coupler 61 is pressed into pen body 63 and is threaded onto threads 82 of point assembly 55. A plug finale 59 is pressed against spring 57 and onto body 63 to seat the refill 56 into its location in pen assembly 50, with its ball point tip 86 extending beyond the nib section 55A on final assembly; so in use, the ball point tip 86 is exposed and ready for use under normal writing pressure, but it retreats against the pressure of spring 57 when heavy pressure is placed on the pen tip 86. Clip 8 and clip cap 9 complete the assembly of pens 50 and 51 of FIGS. 27-30.
The writing instrument affectionately referred to as the "Fat Pen" is indicated at 52 in FIGS. 31 and 32, while its tool kit for assembly and disassembly is shown in FIGS. 33-35 to comprise shaft tool 60, plug with hole 69 and thumb screw 64. The fat pen 52 is seen to comprise the following components in FIGS. 31 and 32; pen body 63, cap portion 73, clip 8 and clip cap 9; in this pen the handsome wood sleeve 73' is tapered to conform to the fat pen style.
While the structural content of the plurality of different writing instruments disclosed herein, the concept of the function of the disassembler members and the tool kits employed is basically the same, and certain different structural parts bear the same reference numerals to indicate their functions are comparable, and no claims are made herein to any of the writing instruments, per se.
To further disclose this invention, there is attached hereto and made a part of this specification, an Exhibit A provides owner instructions for the use of the disassembler and the tool kits disclosed herein as three sheets of data and instructions.
Exhibit B attached hereto is a summary of identification of reference numerals and their corresponding elements in the drawing.
From the foregoing description and examples, it will be seen that there has been produced a writing instrument disassembler and tool kit, and a method of using same that substantially fulfills the objects of this invention, as set forth herein. These inventions are not limited to the examples shown herein, but may be made and performed in many ways within the scope of the appended claims: | 4y
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of my earlier copending application Ser. No. 08/657,376, filed Jun. 3, 1996.
BACKGROUND OF THE INVENTION
This invention relates to a sling assembly for a compound bow used by archers. More particularly, it relates to such an assembly in which the sling can be easily attached to the bow structure without modifying it.
Bow slings which can be removably fastened to a compound bow are known in the prior art. Hughes, in U.S. Pat. No. 4,760,944, which issued on Aug. 2, 1988, discloses such a sling. Hughes' sling includes a pair of mounting members formed of wrap around fabric to which are attached hook and loop type (VELCRO) fasteners. The mounting members are secured to the bow at each of two junctures which are located thereon between one of its limbs and its riser or handle. With the hook and loop type fasteners, the mounting members can be secured to the bow without modifying it. Prior to the bow's being used, however, Hughes' sling must be removed; otherwise, it would interfere with the operation of the bow.
Specht, in U.S. Pat. No. 5,239,976, which issued Aug. 31, 1993, discloses a sling connected to an adapter mounted on a compound bow, which has a cable bar attached thereto. Two embodiments of Specht's sling are taught, including one that can be used in over the shoulder carry and another which can be suspended from a person's belt. Attached to Specht's sling at only a single point, the bow tends to rotate during transport.
SUMMARY OF THE INVENTION
The subject invention is directed to improvements over applicant's prior teachings byway of a sling assembly which fits more closely to the bow, the improved sling assembly having a pair of small angular brackets that are mirror images of each other, each of the brackets having first and second arms which are disposed generally at an obtuse angle to each other and which define an open-ended notch and an elongated slot, respectively. The slot is sized to receive the sling and the notch to accommodate a weight adjustment screw, commonly employed in compound bows at the handle end of each limb. The notch is aligned generally parallel to the longitudinal centerline of the first arm. Together, the first and second arms of each bracket comprise means for rigidly attaching the bracket to the bow and means for connecting the sling to the bracket, respectively. The pair of brackets can be attached in such a way that the sling is disposed, alternatively, on one side or the other of the bow and ideally opposite the handedness of the archer.
In order to attach the brackets in the improved sling assembly to a bow, the weight adjustment screws need not be removed. Rather, each bracket is mounted on the bow by merely loosening one of the weight adjustment screws and then slipping the prongs of the first arm of the bracket around the screw between the proximate surface of the bow and a raised washer usually furnished with the screw. Each of the raised washers provides a tapered seat for receiving the weight adjustment screw inserted therein. Immediately prior to seating the screw, the longitudinal centerlines of the first arm and the proximate bow limb are aligned generally parallel to each other. Once the closed end of the notch abuts the shank of the screw, the screw is seated in the raised washer; and the first arm is simultaneously secured to the bow. The weight adjustment screw is then tightened to obtain a proper amount of tension on the bow using similar procedures to those employed when the bracket is not present. Moreover, a foam pad affixed to the underside of the first arm of each bracket is preferably provided to prevent the bracket, when it is mounted on the bow, from marring it.
Distal ends of the sling, when they are connected to the second arms of the brackets, are attached in such a way that the sling extends on the side of the bow opposite the line of sight, that is, away from any arrow positioned in the bow for firing. Further, the sling is preferably equipped with VELCRO fasteners that can be used, when the bow is fired, to hold the sling in a folded position, shortening its overall length so that it spans only the distance between attachment points of the weight adjustment screws.
In an alternative embodiment, the improved sling assembly also comprises a pair of small angular brackets that are mirror images of each other and have first and second arms which are disposed generally at an obtuse angle to each other. Rather than having an open-ended notch, the first arm defines a hole for receiving one of the weight adjustment screws, the hole having a radius slightly larger than the shank of the screw. As a consequence, the screw must be removed in order to attach the bracket to the bow.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a compound bow with a sling assembly according to the present invention mounted thereon, the archer's body as well as conventional components of the bow being illustrated in dashed lines;
FIGS. 2 and 3 are perspective views, on an enlarged scale, of elements which comprise the lower and upper brackets, respectively, of the sling assembly according to FIG. 1 when the sling assembly is mounted for use by a right-handed archer;
FIG. 4 is a frontal view, on an enlarged scale, of a fragmentary portion of the sling assembly according to FIG. 1;
FIG. 5 is a side elevation view of a fragmentary portion of the sling assembly according to FIG. 1 and of a section of the bow to which the assembly is attached, the weight adjustment screw being shown in a loosened state and the bow being illustrated in dashed lines and partly in cross-section;
FIG. 6 is a side elevation view of the sling assembly according to FIG. 1 showing the sling being held out of the way by having it folded upon itself with its ends secured together;
FIGS. 7 and 8 are perspective views, on an enlarged scale, of elements which comprise upper and lower brackets, respectively, of an alternative embodiment of the sling assembly according to the present invention, when the sling assembly is mounted for use by a right-handed archer;
FIGS. 9 and 10 are frontal views of the bracket according to FIG. 8 and of a fragmentary portion of a sling secured thereto, alternative embodiments of an end of the sling being illustrated in FIGS. 9 and 10, respectively; and
FIGS. 11 and 12 are perspective views, on an enlarged scale, of elements which comprise the lower and upper brackets, respectively, of an alternative embodiment of the sling assembly according to FIG. 1 when the sling assembly is mounted for use by a right-handed archer; and
FIG. 13 is a frontal view, on an enlarged scale, of a fragmentary portion of an alternative embodiment of the sling assembly according to FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1-6, a sling assembly comprising brackets 10, 20 and a sling 30 is removably mounted on a conventional compound bow 40. As is best seen in FIGS. 2 and 3, the brackets 10 and 20 are mirror images of each other, with elements in the bracket 20 being denoted by reference numerals which are greater by the number 10 than those reference numerals which denote corresponding elements in the bracket 10.
Formed from metal or, alternatively, from plastics of various thicknesses, the bracket 10 includes a first arm 11, a second arm 12, and a bend 15 connecting them. Similarly, the bracket 20 has first and second arms 21, 22 and a bend 25 formed of the same material as is the bracket 10. The brackets 10, 20 are preferably fabricated from 1/8 inch thick aluminum alloy material and can be made utilizing the same stamping die.
As illustrated in FIG. 2, the first arm 11 includes two prongs 14, 16 which define an open-ended, elongated notch 13. The notch 13 terminates in a closed end having a radius of curvature slightly larger than that of one of the weight adjustment screws 41. Distal from the closed end, each prong 14, 16 preferably terminates along an edge which is disposed generally perpendicularly to the notch 13.
As further illustrated in FIG. 3, the second arm 22 defines a slot 29 with closed ends. The slot 29 is sized to receive the sling 30 (FIG. 4). Oriented at an obtuse angle relative to the first arm 21, the second arm 22 is disposed roughly in the shape of a "U" which has a base 27 and a sling attachment branch 28, both of which lie generally in the same plane and are oriented perpendicularly to each other. The longitudinal centerlines of the elongated notch 23 and slot 29, on the other hand, are generally disposed in planes lying parallel to each other. Preferably, outside corners of the arm 22 are truncated and rounded; and junctures between the first arm 21 and the base 27 and between the base 27 and the branch 28 include fillets to eliminate any sharp inside corners. With respect to the bracket 10, its elements and their relationships can be described by substituting their respective reference numerals, as explained hereinabove, in the foregoing description.
As is best seen in FIG. 5, a foam pad 44 is affixed to the underside of the bracket 10, 20. The foam pad 44 is employed to hold each of the arms 11, 21 in position once the sling assembly 10 has been mounted on the bow 40.
In preparation for mounting the brackets 10, 20 on the bow 40, its weight adjustment screws 41 and raised washers 42 must first be loosened; but they need not be removed (FIG. 5). Rather, each bracket 10, 20 is mounted on the bow 40 by slipping the first arm 11, 21 of the bracket around one of the loosened screws 41 and between the bow and the raised washer 42 held by the screw.
In order to install the sling assembly on a bow 40 so that it can be used by a right-handed archer, one aligns the bracket 10 so that it can receive the lower weight adjustment screw 41 and positions the bracket 20 proximate with the upper weight adjustment screw (FIGS. 1 and 6). For use by a left-handed archer, one reverses the positions of the brackets 10, 20. In each case, the brackets 10, 20 are preferably positioned with the longitudinal centerlines of the first arm 11, 21 and the proximate bow limb aligned generally parallel to each other, thereby providing a more stable joint between the bow limbs and the brackets than would otherwise be produced.
Once the closed end of the notch 13 abuts the shank of the screw 41, the screw, threadedly engaged with the walls of a hole 45, is tightened sufficiently to secure the raised washer 42, the bracket 10, 20 and the bow 40 in assembled relation. The degree of tightening of the screws 41 determines how much tension is applied to the bow 40. To determine how much tightening of the screws 41 is best, one should follow procedures, commonly recommended by bow manufacturers for adjusting the tension on a compound bow.
Means for retaining distal ends of the sling 30 in the slots 19, 29 of the brackets 10, 20 when the strap is fully extended include a buckle 35 and a thickened end 31, respectively (FIG. 1). Moreover, distal ends of the sling 30 are preferably connected to the second arms 12, 22 of the brackets 10, 20 in such a way that the sling extends on the side of the bow 40 opposite the line of sight, that is, away from any arrow positioned in the bow for firing (FIG. 6). Further, the sling 30 is preferably equipped with VELCRO fasteners 33, 34 that can be used, when the bow 40 is fired, to hold the sling in a folded position, shortening its overall length so that it spans only the distance between attachment points of the weight adjustment screws 41. The hook and loop type fasteners 33, 34 can also be utilized to adjust the overall length of the sling 30 to facilitate carrying the bow 40.
The sling 30, which is preferably fabricated from a strap of flexible material, measures, by way of example, about 1 inch in width, 0.1 inch in thickness and 40 inches in length. The face of the hook and loop-type fastener 33 disposed proximate with the end 31 of the sling 30 is attachable to a mating surface of the fastener 34 situated near the opposite end of the sling, allowing the two ends to be removably affixed to each other.
The brackets 10, 20 are preferably employed to mount the sling assembly on a compound bow 40 since each bracket extends laterally only a very short distance from the surface of the bow. However, in some bows, an arrow quiver is so positioned that it would interfere with the placement of the sling if the mounting brackets 10, 20 were to be used. In such cases, brackets 50, 60 are provided.
As illustrated in FIGS. 7-9, a sling assembly comprising brackets 50, 60 and a strap is removably mounted on a conventional compound bow 40. The brackets 50, 60 are preferably fabricated from 1/8 inch thick aluminum alloy material; but they can also be made out of a wide range of metals or even plastics of various thicknesses. The bracket 50 has a first arm 51, a second arm 52, and a bend 55 connecting the two arms. Moreover, the first arm 51 includes a pair of longitudinally extending prongs 54, 56 which define an open-ended notch 53 (FIG. 7). Oriented at an obtuse angle relative to the first arm 51, the second arm 52 includes an extension base 57 which defines an elongated slot 59, disposed distal from the notch 53, for receiving the sling 30.
As illustrated in FIGS. 7 and 8, the brackets 50, 60 are mirror images of each other. The difference between them is that the bends 55 and 65 are oriented in opposite directions. With respect to the bracket 60, its elements and their relationships can be described by substituting their reference numerals greater by the number 10 for the reference numerals of elements of the bracket 50 in the foregoing description.
Preferably, outside corners of the bracket 50 are truncated and rounded; and junctures between the first and second arms 51, 52, include fillets to eliminate any sharp inside corners.
Mounting the brackets 50, 60 on a compound bow 40 proceeds in a manner similar to that for mounting the brackets 10, 20. The weight adjustment screws 41 and raised washers 43 need not be removed. Rather, each bracket 50, 60 is mounted on the bow 40 by slipping the first arm 51, 61 of the bracket around one of the loosened screws 41 and between the bow and the raised washer 43 held by the screw. For use by a right-handed archer, one positions the brackets 50 and 60 so that each of them can receive the lower and upper weight adjustment screws 41, respectively. For use by a left-handed archer, one reverses the positions of the brackets 50, 60. In each case, the brackets 50, 60 are preferably positioned with the longitudinal centerlines of the first arm 51, 61 and the proximate bow limb aligned generally parallel to each other.
With the closed end of the notch 53, 63 abutting the shank of the screw 41, the screw, threadedly engaged with the walls of a hole formed in the bow 40, is tightened sufficiently to secure the raised washer 43, the bracket 50, 60 and the bow 40 in assembled relation. In tightening the screws 41, one should follow procedures, commonly recommended by bow manufacturers for adjusting the tension on a compound bow.
Also similarly to the brackets 10, 20, a sling 30 with a thickened end 31 and a buckle 35 can be used with the brackets 50, 60 (FIG. 9). Alternatively, a modified sling having a second thickened end 32 instead of the buckle 35 for securing the sling to the brackets 50, 60 can be utilized (FIG. 10). In each embodiment of the strap, one of the mating faces of hook and loop type fasteners 33, 34 is preferably disposed proximate each end of the sling to facilitate securing the two ends thereof together when the sling is folded upon itself.
In a further alternative embodiment illustrated in FIGS. 11-13, a bracket 110 includes first and second arms 111, 112, the first arm defining a hole 114 and preferably terminating along a curved edge 113 which is concentric with the hole. Oriented at an obtuse angle relative to the first arm 111, the second arm 112 is disposed roughly in the shape of a "U" which has a neck 116, a base 117 and a sling attachment branch 118, all of which lie generally in the same plane. The branch 118 defines an elongated slot 119 for receiving the sling 30'. Situated proximate with a bend 115, the neck 116 and sling attachment branch 118 are oriented generally parallel to each other and at right angles to the base 117. Preferably, outside corners of the bracket 110 are truncated and rounded; and junctures between the neck 116 and the base 117 and between the base and the branch 118, as well as between the first and second arms 111, 112, include fillets to eliminate any sharp inside corners.
With respect to the bracket 120, its elements and their relationships can be described by substituting their respective reference numerals, which for each element is greater by 10 than for the corresponding element in the bracket 110, in the foregoing description.
In preparation for mounting the brackets 110, 120 on the bow 40, its weight adjustment screws 41, raised washers 42, and shim washers (not shown) must first be removed. One of the screws 41 is then inserted into a raised washer 42 and through the hole 114 in the first arm 111 of the bracket 110. Alternately, the screw 41 is inserted into a raised washer 42 and the bracket 120.
In order to install the brackets 110, 120 on a bow 40 so that the sling assembly can be used by a left-handed archer, one aligns the bracket 110 with a threaded hole formed in the bow 40 for receiving its upper weight adjustment screw 41 and positions the bracket 120 proximate with the lower weight adjustment screw (FIG. 13). For use by a right-handed archer, one reverses the positions of the brackets 110, 120. Each bracket 110, 120, when it is properly mounted, extends laterally only a very short distance from the surface of the bow.
To complete the mounting process, the screws 41 are threadedly engaged with the walls of holes formed in the bow 40 and tightened sufficiently to secure the washers 42, the brackets 110, 120 and the bow in assembled relation. Since the degree of tightening of the screws 41 determines how much tension is applied to the bow 40, one should follow procedures, commonly recommended by bow manufacturers for adjusting tension on a compound bow.
The sling 30', like the sling 30, is preferably fabricated from a flexible strap which measures, by way of example, about 1 inch in width, 0.1 inch in thickness and 40 inches in length. Inserted into the elongated slots 119, 129, the sling 30' includes thickened ends 31, 32 which prevent it from being pulled out of the slots 129, 119, respectively. Hook and loop type fasteners 33, 34 disposed proximate with the ends 31, 32, respectively, are provided to facilitate securing the two ends together so that the sling can be held in a folded position.
It is understood that those skilled in the art may conceive other applications, modifications and/or changes in the invention described above. Any such applications, modifications or changes which fall within the purview of the description are intended to be illustrative and not intended to be limitative. The scope of the invention is limited only by the scope of the claims appended hereto. | 4y
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[0001] This is a divisional of U.S. application Ser. No. 11/376,397, filed Mar. 15, 2006, the entire disclosure of which is incorporated herein by reference, which is a divisional of U.S. application Ser. No. 10/134,780, filed Apr. 29, 2002, the entire disclosure of which is also incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to peer-to-peer protocols, and more particularly to security framework infrastructures for to peer-to-peer protocols.
BACKGROUND OF THE INVENTION
[0003] Peer-to-peer communication, and in fact all types of communication, depend on the possibility of establishing valid connections between selected entities. However, entities may have one or several addresses that may vary because the entities move in the network, because the topology changes, or because an address lease cannot be renewed. A classic architectural solution to this addressing problem is thus to assign to each entity a stable name, and to “resolve” this name to a current address when a connection is needed. This name to address translation must be very robust, and it must also allow for easy and fast updates.
[0004] To increase the likelihood that an entity's address may be found by those seeking to connect to it, many peer-to-peer protocols allow entities to publish their address through various mechanisms. Some protocols also allow a client to acquire knowledge of other entities' addresses through the processing of requests from others in the network. Indeed, it is this acquisition of address knowledge that enables successful operation of these peer-to-peer networks. That is, the better the information about other peers in the network, the greater the likelihood that a search for a particular resource will converge.
[0005] However, without a robust security infrastructure underlying the peer-to-peer protocol, malicious entities can easily disrupt the ability for such peer-to-peer systems to converge. Such disruptions may be caused, for example, by an entity that engages in identity theft. In such an identity theft attack on the peer-to-peer network, a malicious node publishes address information for IDs with which it does not have an authorized relationship, i.e. it is neither the owner nor a group member, etc. A malicious entity could also intercept and/or respond first before the good node responds, thus appearing to be the good node.
[0006] A malicious entity could also hamper PNRP resolution by flooding the network with bad information so that other entities in the network would tend to forward requests to non-existent nodes (which would adversely affect the convergence of searches), or to nodes controlled by the attacker. This could also be accomplished by modifying the RESOLVE packet used to discover resources before forwarding it along, or by sending an invalid RESPONSE to back to the requestor which generated the RESOLVE packet. A malicious entity could also attempt to disrupt the operation of the peer-to-peer network by trying to ensure that searches will not converge by, for example, instead of forwarding the search to a node in its cache that is closer to the ID to aid in the convergence of the search, forwarding the search to a node that is further away from the requested ID. Alternatively, the malicious entity could simply not respond to the search request at all. The PNRP resolution could be further hampered by a malicious node sending an invalid BYE message on behalf of a valid ID. As a result, other nodes in the cloud will remove this valid ID from their cache, decreasing the number of valid nodes stored therein.
[0007] While validation of an address certificate may prevent the identity theft problem, such is ineffective against this second type of attack that hampers PNRP resolution. An attacker can continue to generate verifiable address certificates (or have them pre-generated) and flood the corresponding IDs in the peer-to-peer cloud. If any of the nodes attempts to verify ownership of the ID, the attacker would be able to verify that it is the owner for the flooded IDs because, in fact, it is. However, if the attacker manages to generate enough IDs it can bring most of the peer-to-peer searches to one of the nodes controlled by him. At this point the attacker can fairly well control and direct the operation of the network.
[0008] If the peer-to-peer protocol requires that all new address information first be verified to prevent the identity theft problem discussed above, a third type of attack becomes available to malicious entities. This attack to which these types of peer-to-peer networks are susceptible is a form of a denial of service (DoS) attack. If all the nodes that learn about new records try to perform the ID ownership check, a storm of network activity against the advertised ID owner will occur. Exploiting this weakness, an attacker could mount an IP DoS attack against a certain target by making that target very popular. For example, if a malicious entity advertises Microsoft's Web IP address as the IDs IP, all the nodes in the peer-to-peer network that receive this advertised IP will try to connect to that IP (Microsoft's Web server's IP) to verify the authenticity of the record. Of course Microsoft's server will not be able to verify ownership of the ID because the attacker generated this information. However, the damage has already been done. That is, the attacker just managed to convince a good part of the peer-to-peer community to attack Microsoft.
[0009] Another type of DoS attack that overwhelms a node or a cloud by exhausting one or more resources is perpetrated by a malicious node that sends a large volume of invalid/valid PACs to a single node, e.g. by using FLOOD/RESOLVE/SOLICIT packets). The node that receives these PACs will consume all its CPU trying to verify all of the PACs. Similarly, by sending invalid FLOOD/RESOLVE packets, a malicious node will achieve packet multiplication within the cloud. That is, the malicious node can consume network bandwidth for a PNRP cloud using a small number of such packets because the node to which these packets are sent will respond by sending additional packets. Network bandwidth multiplication can also be achieved by a malicious node by sending bogus REQUEST messages to which good nodes will respond by FLOODing the PACs, which are of a larger size than the REQUEST.
[0010] A malicious node can also perpetrate an attack in the PNRP cloud by hampering the initial node synch up. That is, to join the PNRP cloud a node tries to connect to one of the nodes already present in the PNRP cloud. If the node tries to connect to the malicious node, it can totally be controlled by that malicious node. Further, a malicious node can send invalid REQUEST packets when two good nodes are involved in the synchronization process. This is a type of DoS attack that will hamper the synch up because the invalid REQUEST packets will initiate the generation of FLOOD messages in response.
[0011] There exists a need in the art, therefore, for security mechanisms that will ensure the integrity of the P2P cloud by preventing or mitigating the effect of such attacks.
BRIEF SUMMARY OF THE INVENTION
[0012] The inventive concepts disclosed in this application involve a new and improved method for inhibiting a malicious node's ability to disrupt normal operation of a peer-to-peer network. Specifically, the present invention presents methods to address various types of attacks that may be launched by a malicious node, including identity theft attacks, denial of service attacks, attacks that merely attempt to hamper the address resolution in the peer-to-peer network, as well as attacks that attempt to hamper a new node's ability to join and participate in the peer-to-peer network.
[0013] The security infrastructure and methods presented allow both secure and insecure identities to be used by nodes by making them self-verifying. When necessary or opportunistic, ID ownership is validated by piggybacking the validation on existing messages or, if necessary, by sending a small inquire message. The probability of connecting initially to a malicious node is reduced by randomly selecting to which node to connect. Further, information from malicious nodes is identified and can be disregarded by maintaining information about prior communications that will require a future response. Denial of service attacks are inhibited by allowing the node to disregard requests when its resource utilization exceeds a predetermined limit. The ability for a malicious node to remove a valid node is reduced by requiring that revocation certificates be signed by the node to be removed.
[0014] In accordance with one embodiment of the present invention, a method of generating a self-verifiable insecure peer address certificate (PAC) that will prevent a malicious node from publishing another node's secure identification in an insecure PAC in the peer-to-peer network is presented. This method comprises the steps of generating an insecure PAC for a resource discoverable in the peer-to-peer network. The resource has a peer-to-peer identification (ID). The method further includes the step of including an uniform resource identifier (URI) in the insecure PAC from which the peer-to-peer ID is derived. Preferably, the URI is in the format “p2p://URI”. The peer-to-peer ID may also be insecure.
[0015] In a further embodiment, a method of opportunistically validating a peer address certificate at a first node in a peer-to-peer network is presented. This first node utilizes a multilevel cache for storage of peer address certificates, and the method comprises the steps of receiving a peer address certificate (PAC) purportedly from a second node and determining in which level of the multilevel cache the PAC is to be stored. When the PAC is to be stored in one of two lowest cache levels, the method places the PAC in a set aside list, generates an INQUIRE message containing an ID of the PAC to be validated, and transmits the INQUIRE message to the second node. When the PAC is to be stored in an upper cache level other than one of the two lowest cache levels, the method stores the PAC in the upper cache level marked as ‘not validated’. In this case, the PAC will be validated the first time it is used. The method may also request a certificate chain for the PAC.
[0016] In a preferred embodiment, generation of the INQUIRE message comprises the step of generating a transaction ID to be included in the INQUIRE message. When an AUTHORITY message is received from the second node in response to the INQUIRE message, the PAC is removed from the set aside list and is stored in the one of the two lowest cache levels. If a certificate chain was requested, the AUTHORITY message is examined to determine if the certificate chain is present and valid. If it is, the PAC is stored in the one of the two lowest cache levels, and if not it is deleted. A transaction ID may also be used in an embodiment of the invention to ensure that the AUTHORITY message is in response to a prior communication.
[0017] In a further embodiment of the present invention, a method of discovering a node in a peer-to-peer network in a manner that reduces the probability of connecting to a malicious node is presented. This method comprises the steps of broadcasting a discovery message in the peer-to-peer network without including any IDs locally registered, receiving a response from a node in the peer-to-peer network, and establishing a peering relationship with the node. In one embodiment, the step of receiving a response from a node comprises the step of receiving a response from at least two nodes in the peer-to-peer network. In this situation, the step of establishing a peering relationship with the node comprises the steps of randomly selecting one of the at least two nodes and establishing a peering relationship with the randomly selected one of the at least two nodes.
[0018] In yet a further embodiment of the present invention, a method of inhibiting a denial of service attack based on a synchronization process in a peer-to-peer network is presented. This method comprises the steps of receiving a SOLICIT message requesting cache synchronization from a first node containing a peer address certificate (PAC), examining the PAC to determine its validity, and dropping the SOLICIT packet when the step of examining the PAC determines that the PAC is not valid. Preferably, when the step of examining the PAC determines that the PAC is valid, the method further comprises the steps of generating a nonce, encrypting the nonce with a public key of the first node, generating an ADVERTISE message including the encrypted nonce, and sending the ADVERTISE message to the first node. When a REQUEST message is received from the first node, the method examines the REQUEST message to determine if the first node was able to decrypt the encrypted nonce, and processes the REQUEST message when the first node was able to decrypt the encrypted nonce.
[0019] Preferably, this method further comprises the steps of maintaining connection information specifically identifying the communication with the first node, examining the REQUEST message to ensure that it is specifically related to the ADVERTISE message, and rejecting the REQUEST message when it is not specifically related to the ADVERTISE message. In one embodiment the step of maintaining connection information specifically identifying the communication with the first node comprises the steps of calculating a first bitpos as the hash of the nonce and the first node's identity, and setting a bit at the first bitpos in a bit vector. When this is done, the step of examining the REQUEST message comprises the steps of extracting the nonce and the first node's identity from the REQUEST message, calculating a second bitpos as the hash of the nonce and the first node's identity, examining the bit vector to determine if it has a bit set corresponding to the second bitpos, and indicating that the REQUEST is not specifically related to the ADVERTISE message when the step of examining the bit vector does not find a bit set corresponding to the second bitpos. Alternatively, the nonce may be used directly as the bitpos. In this case, when the REQUEST is received, the bitpos corresponding to the enclosed nonce is checked. If it is set, this is a valid REQUEST and the bitpos is cleared. Otherwise, this is an invalid REQUEST or replay attack, and the REQUEST is discarded.
[0020] In yet a further embodiment of the present invention, a method of inhibiting a denial of service attack based on a synchronization process in a peer-to-peer network comprises the steps of receiving a REQUEST message purportedly from a first node, determining if the REQUEST message is in response to prior communication with the first node, and rejecting the REQUEST message when the REQUEST message is not in response to prior communication with the first node. Preferably, the step of determining if the REQUEST message is in response to prior communication comprises the steps of extracting a nonce and an identity purportedly of the first node from the REQUEST message, calculating a bitpos as the hash of the nonce and the identity, examining a bit vector to determine if it has a bit set corresponding to the bitpos, and indicating that the REQUEST is not in response to prior communication with the first node when there is no bit set corresponding to the bitpos.
[0021] A method of inhibiting denial of service attacks based on node resource consumption in a peer-to-peer network is also presented. This method comprises the steps of receiving a message from a node in the peer-to-peer network, examining current resource utilization, and rejecting processing of the message when the current resource utilization is above a predetermined level. When a RESOLVE message is received, the step of rejecting processing of the message comprises the step of sending an AUTHORITY message to the first node. This AUTHORITY message contains an indication that the RESOLVE message will not be processed because the current resource utilization too high. When a FLOOD message is received containing a peer address certificate (PAC) and the method determines that the PAC should be stored in one of two lowest cache levels, the step of rejecting processing of the message comprises the step of placing the PAC in a set aside list for later processing. If the method determines that the PAC should be stored in a cache level higher than two lowest cache levels, the step of rejecting processing of the message comprises the step of rejecting the FLOOD message.
[0022] In another embodiment of the present invention, a method of inhibiting denial of service attacks based on node bandwidth consumption in a peer-to-peer network is presented. This method comprises the steps of receiving a request for cache synchronization from a node in the peer-to-peer network, examining a metric indicating a number of cache synchronizations performed in the past, and rejecting processing of the request for cache synchronization when the number of cache synchronization performed in the past exceed a predetermined maximum. In a further embodiment, the method examines the metric to determine the number of cache synchronizations performed during a predetermined preceding period of time. In this embodiment the step of rejecting processing of the request comprises the step of rejecting processing of the request for cache synchronization when the number of cache synchronizations performed in the preceding period of time exceeds a predetermined maximum.
[0023] In another embodiment of the present invention, a method of inhibiting a search based denial of service attack in a peer-to-peer network comprises the steps of examining cache entries of known peer address certificates to determine appropriate nodes to which to send a resolution request, randomly selecting one of the appropriate nodes, and sending the resolution request to the randomly selected node. In one embodiment the step of randomly selecting one of the appropriate nodes comprises the step of calculating a weighted probability for each of the appropriate nodes based on the distance of the PNRP ID from the target ID. The probability of choosing a specific next hop is then determined as an inverse proportionality to the ID distance between that node and the target node.
[0024] In a further embodiment of the present invention, a method of inhibiting a search based denial of service attack in a peer-to-peer network comprises the steps of receiving a RESPONSE message, determining if the RESPONSE message is in response to a prior RESOLVE message, and rejecting the RESPONSE message when the RESPONSE message is not in response to the prior RESOLVE message. Preferably, the step of determining if the RESPONSE message is in response to a prior RESOLVE message comprises the steps of calculating a bitpos as a hash of information in the RESPONSE message, and examining a bit vector to determine if a bit corresponding to the bitpos is set therein.
[0025] In one embodiment wherein the RESPONSE message contains an address list, the method further comprises the steps of determining if the RESPONSE message has been modified in an attempt to hamper resolution, and rejecting the RESPONSE message when the RESPONSE message has been modified in an attempt to hamper resolution. Preferably the step of determining if the RESPONSE message has been modified in an attempt to hamper resolution comprises the steps of calculating a bitpos as a hash of the address list in the RESPONSE message, and examining a bit vector to determine if a bit corresponding to the bitpos is set therein.
[0026] In another embodiment of the present invention, a method of inhibiting a malicious node from removing a valid node from the peer-to-peer network comprises the steps of receiving a revocation certificate purportedly from the valid node having a peer address certificate (PAC) stored in cache, and verifying that the revocation certificate is signed by the valid node.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:
[0028] FIG. 1 is a block diagram generally illustrating an exemplary computer system on which the present invention resides;
[0029] FIG. 2 is a simplified flow diagram illustrating security aspects of AUTHORITY packet processing in accordance with an embodiment of the present invention;
[0030] FIG. 3 is a simplified communications processing flow diagram illustrating security aspects of a synchronization phase of P2P discovery in accordance with an embodiment of the present invention;
[0031] FIG. 4 is a simplified flow diagram illustrating security aspects of RESOLVE packet processing in accordance with an embodiment of the present invention;
[0032] FIG. 5 is a simplified flow diagram illustrating security aspects of FLOOD packet processing in accordance with an embodiment of the present invention; and
[0033] FIG. 6 is a simplified flow diagram illustrating security aspects of RESPONSE packet processing in accordance with an embodiment of the present invention.
[0034] While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
[0035] Turning to the drawings, wherein like reference numerals refer to like elements, the invention is illustrated as being implemented in a suitable computing environment. Although not required, the invention will be described in the general context of computer-executable instructions, such as program modules, being executed by a personal computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Moreover, those skilled in the art will appreciate that the invention may be practiced with other computer system configurations, including hand-held devices, multi-processor systems, microprocessor based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.
[0036] FIG. 1 illustrates an example of a suitable computing system environment 100 on which the invention may be implemented. The computing system environment 100 is only one example of a suitable computing environment and is not intended to suggest any limitation as to the scope of use or functionality of the invention. Neither should the computing environment 100 be interpreted as having any dependency or requirement relating to any one or combination of components illustrated in the exemplary operating environment 100 .
[0037] The invention is operational with numerous other general purpose or special purpose computing system environments or configurations. Examples of well known computing systems, environments, and/or configurations that may be suitable for use with the invention include, but are not limited to, personal computers, server computers, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like.
[0038] The invention may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.
[0039] With reference to FIG. 1 , an exemplary system for implementing the invention includes a general purpose computing device in the form of a computer 110 . Components of computer 110 may include, but are not limited to, a processing unit 120 , a system memory 130 , and a system bus 121 that couples various system components including the system memory to the processing unit 120 . The system bus 121 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Associate (VESA) local bus, and Peripheral Component Interconnect (PCI) bus also known as Mezzanine bus.
[0040] Computer 110 typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computer 110 and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computer 110 . Communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of the any of the above should also be included within the scope of computer readable media.
[0041] The system memory 130 includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) 131 and random access memory (RAM) 132 . A basic input/output system 133 (BIOS), containing the basic routines that help to transfer information between elements within computer 110 , such as during start-up, is typically stored in ROM 131 . RAM 132 typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 120 . By way of example, and not limitation, FIG. 1 illustrates operating system 134 , application programs 135 , other program modules 136 , and program data 137 .
[0042] The computer 110 may also include other removable/non-removable, volatile/nonvolatile computer storage media. By way of example only, FIG. 1 illustrates a hard disk drive 141 that reads from or writes to non-removable, nonvolatile magnetic media, a magnetic disk drive 151 that reads from or writes to a removable, nonvolatile magnetic disk 152 , and an optical disk drive 155 that reads from or writes to a removable, nonvolatile optical disk 156 such as a CD ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive 141 is typically connected to the system bus 121 through a non-removable memory interface such as interface 140 , and magnetic disk drive 151 and optical disk drive 155 are typically connected to the system bus 121 by a removable memory interface, such as interface 150 .
[0043] The drives and their associated computer storage media discussed above and illustrated in FIG. 1 , provide storage of computer readable instructions, data structures, program modules and other data for the computer 110 . In FIG. 1 , for example, hard disk drive 141 is illustrated as storing operating system 144 , application programs 145 , other program modules 146 , and program data 147 . Note that these components can either be the same as or different from operating system 134 , application programs 135 , other program modules 136 , and program data 137 . Operating system 144 , application programs 145 , other program modules 146 , and program data 147 are given different numbers hereto illustrate that, at a minimum, they are different copies. A user may enter commands and information into the computer 110 through input devices such as a keyboard 162 and pointing device 161 , commonly referred to as a mouse, trackball or touch pad. Other input devices (not shown) may include a microphone, joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit 120 through a user input interface 160 that is coupled to the system bus, but may be connected by other interface and bus structures, such as a parallel port, game port or a universal serial bus (USB). A monitor 191 or other type of display device is also connected to the system bus 121 via an interface, such as a video interface 190 . In addition to the monitor, computers may also include other peripheral output devices such as speakers 197 and printer 196 , which may be connected through a output peripheral interface 195 .
[0044] The computer 110 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 180 . The remote computer 180 may be another personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the personal computer 110 , although only a memory storage device 181 has been illustrated in FIG. 1 . The logical connections depicted in FIG. 1 include a local area network (LAN) 171 and a wide area network (WAN) 173 , but may also include other networks. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets and the Internet.
[0045] When used in a LAN networking environment, the personal computer 110 is connected to the LAN 171 through a network interface or adapter 170 . When used in a WAN networking environment, the computer 110 typically includes a modem 172 or other means for establishing communications over the WAN 173 , such as the Internet. The modem 172 , which may be internal or external, may be connected to the system bus 121 via the user input interface 160 , or other appropriate mechanism. In a networked environment, program modules depicted relative to the personal computer 110 , or portions thereof, may be stored in the remote memory storage device. By way of example, and not limitation, FIG. 1 illustrates remote application programs 185 as residing on memory device 181 . It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used.
[0046] In the description that follows, the invention will be described with reference to acts and symbolic representations of operations that are performed by one or more computer, unless indicated otherwise. As such, it will be understood that such acts and operations, which are at times referred to as being computer-executed, include the manipulation by the processing unit of the computer of electrical signals representing data in a structured form. This manipulation transforms the data or maintains it at locations in the memory system of the computer, which reconfigures or otherwise alters the operation of the computer in a manner well understood by those skilled in the art. The data structures where data is maintained are physical locations of the memory that have particular properties defined by the format of the data. However, while the invention is being described in the foregoing context, it is not meant to be limiting as those of skill in the art will appreciate that various of the acts and operation described hereinafter may also be implemented in hardware.
[0047] As introduced above, the success of a peer-to-peer (P2P) protocol depends on the protocol's ability to establish valid connections between selected entities. Because a particular user may connect to the network in various ways at various locations having different addresses, a preferred approach is to assign a unique identity to the user, and then resolve that identity to a particular address through the protocol. Such a peer-to-peer name resolution protocol (PNRP) to which the security infrastructure of the instant invention finds particular applicability is described in co-pending application Ser. No. 09/942,164, entitled Peer-To-Peer Name Resolution Protocol (PNRP) And Multilevel Cache For Use Therewith, filed on Aug. 29, 2001, the teachings and disclosure of which are hereby incorporated in their entireties by reference thereto. However, one skilled in the art will recognize from the following teachings that the security infrastructure and methods of the present invention are not limited to the particular peer-to-peer protocol of this co-pending application, but may be applied to other protocols with equal force.
[0048] As discussed in the above-incorporated co-pending application, the peer name resolution protocol (PNRP) is a peer-based name-to-address resolution protocol. Names are 256-bit numbers called PNRP IDs. Addresses consist of an IPv4 or TPv6 address, a port, and a protocol number. When a PNRP ID is resolved into an address, a peer address certificate (PAC) is returned. This certificate includes the target's PNRP ID, current IP address, public key, and many other fields. An instance of the PNRP protocol is called a node. A node may have one or more PNRP IDs registered locally. A node makes an ID-to-address mapping discoverable in PNRP via registration. Each registration includes a locally constructed peer certificate, and requires an appropriate view of the PNRP cache. Hosts which are not PNRP nodes may resolve PNRP IDs into IP addresses via a PNRP DNS gateway. A PNRP DNS gateway accepts DNS ‘A’ and ‘AAAA’ queries, performs a PNRP search for a subset of the hostname specified, and returns the results as a DNS query answer.
[0049] As indicated above, PNRP provides a peer-based mechanism associating P2P and PNRP IDs with peer address certificates (PACs). A P2P ID is a persistent 128-bit identifier. P2P IDs are created by hashing a correctly formatted P2P name. There are two types of P2P IDs, secure and insecure. A secure P2P ID is an ID with a verifiable relationship to a public key. An insecure P2P ID is any ID which is not secure. A given P2P ID may be published by many different nodes. PNRP uses a ‘service location’ suffix to ensure each published instance has a unique PNRP ID. A ‘service location’ is a 128-bit number corresponding to a unique network service endpoint. Service locations have some recognizable elements, but should be considered opaque by PNRP clients. A service location has two important properties. At any moment, only one socket in the cloud corresponds to a given service location. When two service locations are compared, the length of the common prefix for each is a reasonable measure of network proximity. Two service locations which start with the same four bits are no further apart than two which start with the same three bits.
[0050] A P2P ID is uniquely identified by its catenation with the service location. The resulting 256-bit (32 byte) identifier is called a PNRP ID. PNRP nodes register a PNRP ID by invoking PNRP services with a P2P name, authority, and several other parameters. PNRP services then creates and maintains a Peer Address Certificate (PAC) containing the submitted data. PACs include at a minimum a PNRP ID, certificate validity interval, service and PNRP address, public key, and a cryptographic signature generated over select PAC contents.
[0051] Creation and registration of PNRP IDs is only one part of the PNRP service. The PNRP service execution can be divided into four phases. The first is PNRP cloud discovery. During this phase a new node must find an existing node in the cloud it wishes to join. The cloud may be the global PNRP cloud, a site local (enterprise) cloud, or a link local cloud. Once found, the second phase of joining a PNRP cloud is entered. Once the new node has found an existing node, it performs a SYNCHRONIZE procedure to obtain a copy of the existing nodes top cache level. A single cache level provides enough basis for a new node to start participating in the cloud. Once the SYNCHRONIZATION has been achieved, the next phase, active participation in the cloud, may be begun. After initialization has completed, the node may participate in PNRP ID registration and resolution. During this phase, the peer also performs regular cache maintenance. When the node is done, it enters the fourth phase, leaving the cloud. The node un-registers any locally registered PNRP IDs, then terminates.
[0052] The PNRP protocol consists of nine different types of packets, some of which have been introduced above. It should be noted, however, that in this application the names of the packets are used merely to facilitate an understanding of their functionality, and should not be taken as limiting the form or format of the packet or message itself. The RESOLVE packet requests resolution of a target PNRP ID into a PAC. A RESPONSE packet is the result of a completed RESOLVE request. The FLOOD packet contains a PAC intended for the PNRP cache of the recipient. A SOLICIT packet is used to ask a PNRP node to ADVERTISE its top level cache. The requested ADVERTISE packet contains a list of PNRP IDs for PACs in a node's top level cache. A REQUEST packet is used to ask a node to flood a subset of ADVERTISE'd PACs. An INQUIRE packet is used to insecurely ask a node whether a specific PNRP ID is registered at that node. To confirm local registration of a PNRP ID, an AUTHORITY packet is used. This packet optionally provides a certification chain to help validate the PAC for that ID. An ACK packet acknowledges receipt and/or successful processing of certain messages. Finally, the REPAIR packet is used to try to merge clouds that may be split.
[0053] Once a node is fully initialized, it may participate in the PNRP cloud by performing five types of activities. First, a node may register and un-register PNRP IDs. When a PNRP ID is registered, the PNRP service creates a peer address certificate (PAC) associating the PNRP ID, service address port and protocol, PNRP address port and protocol, and a public key. This PAC is entered into the local cache, and a RESOLVE is initiated using the new PAC as the source, and [PNRP ID+1] as the target. This RESOLVE is processed by a number of nodes with PNRP IDs very similar to the registered ID. Each recipient of the RESOLVE adds the new node's PAC to their cache, thereby advertising the new PNRP ID in the cloud. When a PNRP ID is un-registered, an updated PAC is created with a ‘revoke’ flag set. The updated PAC is flooded to all entries in the lowest level of the local cache. Each recipient of the FLOOD checks its cache for an older version of the PAC. If one is found, the recipient removes the PAC from its cache. If the PAC is removed from the lowest cache level, the recipient in turn FLOODs the revocation to the PNRP nodes represented by all other PACs in its lowest cache level.
[0054] The PNRP node may also participate in PNRP ID resolution. As discussed in the above incorporated application, PNRP IDs are resolved into PACs by routing RESOLVE messages successively closer to the target PNRP ID. When a node receives a RESOLVE, it may reject the RESOLVE back to the previous hop, respond to the previous hop with a RESPONSE, or forward the RESOLVE to a node whose PNRP ID is closer to the target ID than the node's own. The node also receives and forwards RESPONSE packets as part of resolution. The PNRP node may also initiate RESOLVEs on behalf of a local client. The PNRP service provides an API to allow asynchronous resolution requests. The local node originates RESOLVE packets, and eventually receives a corresponding RESPONSE.
[0055] The PNRP node also honors cache synchronization requests. Upon receiving a SOLICIT packet, the node responds with an ADVERTISE packet, listing the PNRP IDs in its highest cache level. The solicitor node then sends a REQUEST listing the PNRP IDs for any ADVERTISE'd PACs it wants. Each REQUESTed cache entry is then FLOODed to the REQUESTor. Finally, and as will be discussed more fully below, the PNRP also performs identity validation. Identity validation is a threat mitigation device used to validate PACs. Identity validation basically has two purposes. First, identity validation ensures that the PNRP node specified in a PAC has the PNRP ID from that PAC locally registered. Second, for secure PNRP IDs (discussed below), identity validation ensures that the PAC was signed using a key with a cryptographically provable relationship to the authority in the PNRP ID.
[0056] Having now provided a working knowledge of the PNRP system for which an embodiment of the security infrastructure of the present invention finds particular relevance, attention is now turned to the security mechanisms provided by the security infrastructure of the present invention. These mechanisms are provided by the system of the present invention to eliminate, or at a minimum mitigate, the effect of the various attacks that may be posed by a malicious node in a P2P cloud as discussed above. The PNRP protocol does not have any mechanism to prevent these attacks, nor is there a single solution to address all of these threats. The security infrastructure of the present invention, however, minimizes the disruption that may be caused by a malicious node, and may be incorporated into the PNRP protocol.
[0057] As with many successful P2P protocols, entities can be published for easy discovery. To provide security and integrity to the P2P protocol, however, each identity preferably includes an attached identity certificate. However, a robust security architecture will be able to handle both secure and insecure entities. In accordance with an embodiment of the present invention, this robustness is provided through the use of self-verifying PACs.
[0058] A secure PAC is made self-verifying by providing a mapping between the ID and a public key. This will prevent anyone from publishing a secure PAC without having the private key to sign that PAC, and thus will prevent a large number of identity theft attacks. The keeper of the ID private key uses the certificate to attach additional information to the ID, such as the IP address, friendly name, etc. Preferably, each node generates its own pair of private-public keys, although such may be provided by a trusted supplier. The public key is then included as part of the node identifier. Only the node that created the pair of keys has the private key with which it can prove that it is the creator of the node identity. In this way, identity theft may be discovered, and is, therefore, deterred.
[0059] A generic format for such certificates may be represented as [Version, ID, <ID Related Info>, Validity, Algorithms, P Issuer ]K Issuer . Indeed, P2P name/URL is part of the basic certificate format, regardless of whether it is a secure or insecure ID. As used in this certificate representation, Version is the certificate version, ID is the identifier to be published, <ID Related Info> represents information to be associated with the ID, Validity represents the period of validity expressed in a pair of From-To dates expressed as Universal Date Time (aka GMT), Algorithms refers to the algorithms used for generating the key pairs, and for signing, and P Issuer is the public key of the certificate issuer. If the certificate issuer is the same as the ID owner then this is P ID the public key of the ID owner. The term K Issuer is the private key corresponding to P Issuer . If the certificate issuer is the ID owner then this is K ID , the private key of the ID owner.
[0060] In a preferred embodiment, the <ID related info> comprises the address tuple where this ID can be found, and the address tuple for the PNRP service of the issuer. In this embodiment, the address certificate becomes [Version, ID, <Address> ID , <Address> PNRP , Validity, Revoke Flag, Algorithms, P Issuer ]K Issuer . In this expanded representation, the ID is the identifier to be published, which can be a Group ID or Peer ID. The <Address> is the tuple of IPv6 address, port, and protocol. <Address> ID is the address tuple to be associated with the ID. <Address> PNRP is the address tuple of the PNRP service (or other P2P service) on the issuer machine. This is preferably the address of the PNR ID address of the issuer. It will be used by the other PNRP nodes to verify the validity of the certificate. Validity is the period of validity expressed in a pair of From-To dates. The Revoke Flag, when set, marks a revocation certificate. The P Issuer is the public key of the certificate issuer, and the K Issuer is the private key corresponding to P Issuer . If the certificate issuer is the ID owner then this is K ID , the private key of the ID.
[0061] In a preferred embodiment of the present invention, the following conditions have to be met for a certificate to be valid. The certificate signature must valid, and the certificate cannot be expired. That is, the current date expressed as UDT must be in the range specified by the Validity field. The hash of the public key must also match the ID. If the Issuer is the same as the ID owner then the hashing of the issuer's public key into the ID has to verify. If the P Issuer is different from P ID then there must be a chain of certificates leading to a certificate signed with K ID . Such a chain verifies the relationship between the issuer and the ID owner. Additionally, in the case when a certification revocation list (CRL) is published for that class of IDs and the CRL is accessible, then the authenticator can verify that none of the certificates in the chain appear in the CRL.
[0062] The security infrastructure of the present invention also handles insecure PACs. In accordance with the present invention, an insecure PAC is made self-verifying by including the uniform resource identifier (URI) from which the ID is derived. Indeed, both secure and insecure IDs include the URI in the PAC. The URI is of the format “p2p://URI”. This will prevent a malicious node from publishing another node's secure ID in an insecure PAC.
[0063] The security infrastructure of the present invention also allows for the use of insecure IDs. The problem with such insecure ID is that they are very easy to forge. A malicious node can publish an insecure ID of any other node. Insecure IDs also open security holes wherein it becomes possible to make discovery of a good node difficult. However, by including an URI in accordance with the present invention, the insecure IDs cannot affect the secure IDs in any way. Further, the infrastructure of the present invention requires that the PACs containing insecure ID be in the same format as secure PACs, i.e. they contain public key and private keys. By enforcing the same structure on insecure PACs as on secure PACs, the bar for generation of PACs is not lowered. Further, by including an URI in the PAC it is not computationally feasible to generate a URI that maps to a specific secure ID.
[0064] One issue that arises is when should the PACs be verified, recognizing a trade off between increased P2P cloud security and increased overhead. The PAC contained in the various packets discussed above has to be verified at some point, however. This PAC verification includes checking if the ID signature is valid or not and checking if the ID corresponds to the public key for secure IDs. To balance the overhead versus security issues, one embodiment of the present invention verifies the PACs before any processing of that packet is done. This ensures that invalid data is never processed. However, recognizing that PAC verification may slow down the processing of packets, which might not be suitable for certain classes of packets, e.g. RESOLVE packets, an alternate embodiment of the present invention does not verify the PAC in these packets.
[0065] In addition to the verification of the PAC, the security infrastructure of the present invention also performs an ID ownership check to validate the PAC. As discussed above, identity theft can be discovered by simple validation of the address certificate before using that address in PNRP or other P2P protocols. This validation may entail simply verifying that the ID is the hash of the public key included in the certificate. The ownership validation may also entail the issuance of an INQUIRE packet to the address in that PAC. The INQUIRE packet will contain the ID to be verified, and a transaction ID. If the ID is present at that address, the node should acknowledge that INQUIRE. If the ID is not present at that address, the node should not acknowledge that INQUIRE. If the certificate chain is required to verify the identity, the node returns the complete certificate chain. While signature and ID->URL validation is still complex and a significant use of resources, as is validating the chain of trust in a supplied cert chain, the system of the present invention avoids any sort of challenge/response protocol, which would add an additional level of complexity to PAC validation. Further, the inclusion of the transaction ID prevents the malicious node from pre-generating the response to the INQUIREs. Additionally, this mechanism dispenses with the requirement that the PAC carry the complete certificate chain.
[0066] The ID ownership check is also facilitated in the system of the present invention by modifying the standard RESOLVE packet so that it can also perform the ID ownership check. This modified RESOLVE packet contains the ID of the address to which the RESOLVE is being forwarded. If the ID is at that address it will send an ACK, otherwise it will send a NACK. If the ID does not process the RESOLVE or if a NACK is received, the ID is removed from the cache. In this way a PAC is validated without resorting to any sort of challenge/response protocol and without sending any special INQUIRE packet by, in essence, piggybacking an INQUIRE message with the RESOLVE. This piggybacking process will be discussed again below with respect to FIG. 2 . This procedure makes it easy to flush out invalid or stale PACs.
[0067] This identity validation check happens at two different times. The first is when a node is going to add a PAC to one of its lowest two cache levels. PAC validity in the lowest two cache levels is critical to PNRP's ability to resolve PNRP IDs. Performing identity validation before adding a PAC to either of these two levels mitigates several attacks. ID ownership is not performed if the PAC is to be added to any higher level cache because of the turnover in these higher levels. It has been determined that nearly 85% of all PAC entries in the higher levels of cache are replaced or expire before they are ever used. As such, the probability of seeing any effect from having an invalid PAC in these higher levels is low enough not to justify performing the ID validation when they are entered.
[0068] When it is determined that an entry would belong in one of the two lowest cache levels, the PAC is placed in a set aside list until its identity can be validated. This first type of identity validation uses the INQUIRE message. Such an identity validation confirms a PAC is still valid (registered) at its originating node, and requests information to help validate authority of the originating node to publish that PAC. One flag in the INQUIRE message is defined for the ‘flags’ field, i.e. RF_SEND_CHAIN, that requests the receiver to send a certificate chain (if any exists) in an AUTHORITY response. If the receiver of the INQUIRE does not have authority to publish the PAC or if the PAC is no longer locally registered, the receiver simply drops the INQUIRE message. Since the local node does not receive a proper response via an AUTHROITY message, the bad PAC will never be entered into its cache, and therefore can have no malicious effect on its operation in the P2P cloud.
[0069] If the receiver of the INQUIRE does have the authority to issue the PAC and if it is still locally registered, that node will respond 200 to the INQUIRE message with an AUTHORITY message as illustrated in FIG. 2 . While not illustrated in FIG. 2 , the receiving node in an embodiment of the present invention checks to see if the AUTHORITY message says that the ID is still registered at the node which sent the AUTHORITY. Once the local node determines 202 that this AUTHORITY message is in response to the INQUIRE message, it removes the PAC from the set aside list 204 . If the certificate chain was requested 206 , the AUTHORITY message is checked to see if the certificate chain is present and valid 208 . If the certificate chain is present and valid, then the PAC is added to the cache and marked as valid 210 . Otherwise, the PAC is deleted 212 . If the certificate chain was not requested 206 , then the PAC is simply added to the cache and marked as valid 210 .
[0070] As may now be apparent, this AUTHORITY message is used to confirm or deny that a PNRP ID is still registered at the local node, and optionally provides a certificate chain to allow the AUTHORITY recipient to validate the node's right to publish the PAC corresponding to the target ID. In addition to the INQUIRE message, the AUTHORITY message may be a proper response to a RESOLVE message as will be discussed below. The AUTHORITY message includes various flags that may be set by the receiving node to indicate a negative response. One such flag is the AF_REJECT_TOO_BUSY flag, which is only valid in response to a RESOLVE. This flag indicates that the host is too busy to accept a RESOLVE, and tells the sender that it should forward the RESOLVE elsewhere for processing. While not aiding in the identity validation, it is another security mechanism of the present invention to prevent a DoS attack as will be discussed more fully below. The flag AF_INVALID_SOURCE, which is only valid in response to a RESOLVE, indicates that the Source PAC in the RESOLVE is invalid. The AF_INVALID_BEST_MATCH flag, which is also only valid in response to a RESOLVE, indicates that the ‘best match’ PAC in the RESOLVE is invalid. The AF_UNKNOWN_ID flag indicates that the specified ‘validate’ PNRP ID is not registered at this host. Other flags in the AUTHORITY message indicate to the receiving node that requested information is included. The AF_CERT_CHAIN flag indicates that a certificate chain is included that will enable validation of the relationship between the ‘validate’ PNRP ID and the public key used to sign its PAC. The AUTHORITY message is only sent as an acknowledgement/response to either the INQUIRE or RESOLVE messages. If an AUTHORITY is ever received out of this context, it is discarded.
[0071] The second time that identity validation is performed is opportunistically during the RESOLVE process. As discussed, PNRP caches have a high rate of turnover. Consequently, most cache entries are overwritten in the cache before they are ever used. Therefore, the security infrastructure of the present invention does not validate these PACs until and unless they are actually used. When a PAC is used to route a RESOLVE path, the system of the present invention piggybacks identity validation on top of the RESOLVE packet as introduced above. The RESOLVE contains a ‘next hop’ ID which is treated the same as the ‘target ID’ in an INQUIRE packet. This RESOLVE is then acknowledged with an AUTHORITY packet, the same as is expected for an INQUIRE discussed above. If an opportunistic identity validation fails, the receiver of the RESOLVE is not who the sender believes they are. Consequently, the RESOLVE is routed elsewhere and the invalid PAC is removed from the cache.
[0072] This process is also illustrated in FIG. 2 . When a PNRP node P receives an AUTHORITY packet 200 with the header Message Type field set to RESOLVE 202 , the receiving node examines the AUTHORITY flags to determine if this AUTHORITY flag is negative 214 , as discussed above. If any of the negative response flags are set in the AUTHORITY message, the PAC is deleted 216 from the cache and the RESOLVE is routed elsewhere. The address to which the RESOLVE was sent is appended to the RESOLVE path and marked REJECTED. The RESOLVE is then forwarded to a new destination. If the AUTHORITY is not negative and if the certificate chain was requested 218 , the AUTHORITY message flag AF_CERT_CHAIN is checked to see if the certificate chain is present. If it is present the receiving node should perform a chain validation operation on the cached PAC for the PNRP ID specified in validate. The chain should be checked to ensure all certificates in it are valid, and the relationship between the root and leaf of the chain is valid. The hash of the public key for the chain root should, at a minimum, be compared to the authority in the PACs P2P name to ensure they match. The public key for the chain leaf should be compared against the key used to sign the PAC to ensure they match. If any of these checks fail or if the certificate chain is not present when requested 220 , the PAC should be removed from the cache 222 and the RESOLVE reprocessed. If the requested certificate chain is included and is validated 220 , the PAC corresponding to the validate PNRP ID should be marked as fully validated 224 . If desired, the PNRP ID, PNRP service address, and validation times may be retained from the PAC and the PAC itself deleted from the cache to save memory.
[0073] As an example of this identity validation, assume that P is a node requesting an identity validation for PNRP ID ‘T’. N is the node receiving the identity validation request. This could happen as a result of P receiving either an INQUIRE packet with target ID=T, or a RESOLVE packet with next hop=T. N checks its list of PNRP IDs registered locally. If T is not in that list, then the received packet type is checked. If it was an INQUIRE, N silently drops the INQUIRE request. After normal retransmission attempts expire, P will discard the PAC as invalid and processing is done. If it was a RESOLVE, N responds with an AUTHORITY packet indicating ID T is not locally registered. P then sends the RESOLVE elsewhere. If T is in the list of PNRP IDs at N, N constructs an AUTHORITY packet and sets the target ID to T. If T is an insecure ID, then N sends the AUTHORITY packet to P. If T is a secure ID, and the authority for the secure ID is the key used to sign the PAC, then N sends the AUTHORITY packet to P. If neither of these are true and if the RF_SEND_CHAIN flag is set, then N retrieves the certificate chain relating the key used to sign the PAC to the authority for PNRP ID T. The certificate chain is inserted into the AUTHORITY packet, and then N sends the AUTHORITY packet to P. At this point, if T is an insecure ID processing is completed. Otherwise, P validates the relationship between the PAC signing key and the authority used to generate the PNRP ID T. If the validation fails, the PAC is discarded. If validation fails and the initiating message was a RESOLVE, P forwards the RESOLVE elsewhere.
[0074] As may now be apparent from these two times that identity ownership verification is performed, through either the INQUIRE or the modified RESOLVE packet, an invalid PAC cannot be populated throughout the P2P cloud using a FLOOD, and searches will not be forwarded to non-existent or invalid IDs. The PAC validation is necessary for FLOOD because, if the FLOOD packet is allowed to propagate in the network without any validation, then it might cause a DoS attack. Through these mechanisms, a popular node will not be flooded with ID ownership check because its ID will belong to only a very few nodes' lowest two cache levels.
[0075] As described more fully in the above referenced co-pending application, a PNRP node N learns about a new ID in one of four ways. It may learn of a new ID through the initial flooding of a neighbor's cache. Specifically, when a P2P node comes up it contacts another node member of the P2P cloud and initiates a cache synchronization sequence. It may also learn of a new ID as a result of a neighbor flooding a new record of its lowest cache. For example, assume that node N appears as an entry in the lowest level cache of node M. When M learns about a new ID, if the ID fits in its lowest level cache, it will flood it to the other entries in that cache level, respectively to N. A node may also learn of a new ID as a result of a search request. The originator of a search request inserts its address certificate in the request, and the PAC for the ‘best match’ to the search request so far also inserts its PAC into the request. In this way, all of the nodes along the search request path will update their cache with the search originator's address, and the best match's address. Similarly, a node may learn of a new ID as a result of a search response. The result of a search request travels a subset of the request path in reversed order. The nodes along this path update their cache with the search result.
[0076] According to PNRP, when the node first comes up it discovers a neighbor. As discussed above, however, if the node that is first discovered is a malicious node, the new node can be controlled by the malicious node. To prevent or minimize the possibility of such occurrence, the security infrastructure of the present invention provides two mechanisms to ensure secure node boot up. The first is randomized discovery. When a node tries to discover another node that will allow him to join the PNRP cloud, the last choice for discovery is using multicast/broadcast because it is the most insecure discovery method of PNRP. Due to the nature of discovery it is very difficult to distinguish between a good and bad node. Therefore, when this multicast/broadcast method is required, the security infrastructure of the present invention causes the node to randomly select one of the nodes who responded to the broadcast discovery (MARCOPOLO or an existing multicast discovery protocol e.g. SSDP) message. By selecting a random node, the system of the present invention minimizes the probability of selecting a bad node. The system of the present invention also performs this discovery without using any of its IDs. By not using IDs during discovery, the system of the present invention prevents the malicious node from targeting a specific ID.
[0077] A second secure node boot up mechanism is provided by a modified sync phase during which the node will maintain a bit vector. This modified synch phase mechanism may best be understood through an example illustrated in the simplified flow diagram of FIG. 3 . Assume that Alice 226 sends a SOLICIT 228 to Bob 230 with her PAC in it. If Alice's PAC is not valid 232 , Bob 230 simply drops the SOLICIT 234 . If the PAC is valid, Bob 230 will then maintain a bit vector for storing the state of this connection. When this SOLICIT is received, Bob 230 generates 236 a nonce and hashes it with Alice's PNRP ID. The resulting number will be used as an index in this bit vector that Bob will set. Bob 230 then responds 238 to Alice 226 with an ADVERTISE message. This ADVERTISE will contain Bob's PAC and a nonce encrypted with Alice's public key, apart from other information, and will be signed by Bob 230 . When Alice 226 receives this ADVERTISE, she verifies 240 the signature and Bob's PAC. If it cannot be verified, it is dropped 241 . If it can be verified, Alice 226 then decrypts 242 the nonce. Alice 226 will then generate 244 a REQUEST that will contain this nonce and Alice's PNRP ID. Bob 230 will process 246 this REQUEST by hashing Alice's PNRP ID with the nonce sent in the REQUEST packet. If 248 the bit is set in the bit vector having the hashed results as an index, then Bob will clear the bits and start processing REQUEST 250 . Otherwise, Bob will ignore the REQUEST 252 as it may be a replay attack.
[0078] This makes the node boot up a secure process because the sequence cannot be replayed. It requires minimal overhead in terms of resources consumed, including CPU, network ports, and network traffic. No timers are required to be maintained for the state information, and only the ID that initiated the sync up will be sent data. Indeed, this modified sync phase is asynchronous, which allows a node to process multiple SOLICITs simultaneously.
[0079] Many of the threats discussed above can be minimized by controlling the rate at which the packets are processed, i.e. limiting node resource consumption. The idea behind this is that a node should not consume 100% of its CPU trying to process the PNRP packets. Therefore, in accordance with an embodiment of the present invention a node may reject processing of certain messages when it senses that such processing will hinder its ability to function effectively.
[0080] One such message that the node may decide not to process is the RESOLVE message received from another node. This process is illustrated in simplified form in FIG. 4 . Once a RESOLVE messages is received 254 , the node will check 256 to see if it is currently operating at a CPU capacity greater than a predetermined limit. If its CPU is too busy to process the RESOLVE message, it will send 258 an AUTHORITY message with the AF_REJECT_TOO_BUSY flag set indicating its failure to process the request because it is too busy. If the CPU is not too busy 256 , the node will determine 260 if all of the PACs in the RESOLVE message are valid, and will reject 262 the message if any are found to be invalid. If all of the PACs are valid 260 , the node will process 264 the RESOLVE.
[0081] If the node can respond 266 to the RESOLVE, the node will 268 convert the RESOLVE into a RESPONSE and send it to the node from which it received the RESOLVE. If, however, the target ID is not locally registered, the node will 270 calculate the bitpos as the hash of the fields in the RESOLVE and will set the corresponding bitpos in the bit vector. As discussed briefly above, this bit vector is used as a security mechanism to prevent the processing of erroneous reply messages when the node has not sent out any messages to which a reply is expected. The node finds the next hop to which to forward the RESOLVE, with the appropriate modifications to evidence its processing of the message. If 272 the node to which the RESOLVE is to be forwarded has already been verified, the node simply forwards 276 the RESOLVE to that next hop. If 272 this selected next hop has not yet been verified, the node piggybacks 274 an ID ownership request on the RESOLVE and forwards 276 it to that node. In response to the piggybacked ID ownership request, the node will expect to receive an AUTHORITY message as discussed above, the process for which is illustrated in FIG. 2 . As illustrated in FIG. 2 , if a validating AUTHORITY is not received at step 214 , the PAC of the node to which the RESOLVE was forwarded is deleted 216 from the cache and the RESOLVE is reprocessed from step 254 of FIG. 4 .
[0082] Another message that the node may decide not to process because its CPU is too busy is the FLOOD message. In this process, illustrated in simplified form in FIG. 5 , if 278 the new information present in the FLOOD goes to either of the lowest two cache levels, the PAC is checked to determine if it is valid 280 . If the PAC is not valid, the FLOOD is rejected 284 . However, if the PAC is valid 280 , it is put into a set-aside list 282 . The entries in the set-aside list are taken at random intervals and are processed when the CPU is not too busy. Since these entries are going to be entered in the lowest two levels of cache, both the ID verification and the ownership validation are performed as discussed above. If 278 the new information present in the FLOOD goes to the higher cache levels and the CPU is too busy to process them 286 , then they are discarded 288 . If the node has available CPU processing capacity 286 , the PAC is checked to determine if it is valid 290 . If it is, then the PAC is added to the cache 292 , otherwise the FLOOD is rejected 294 .
[0083] Node boot up (SYNCHRONIZE) is another process that consumes considerable resources at a node, including not only CPU processing capacity but also network bandwidth. However, the synchronization process is required to allow a new node to fully participate in the P2P cloud. As such, the node will respond to the request from another node for the boot up if it has enough available resources at the given time. That is, as with the two messages just discussed, the node may refuse to participate in the boot up if its CPU utilization is too high. However, since this process consume so much capacity, a malicious node can still exploit this by launching a large number of such sequences. As such, an embodiment of the security infrastructure of the present invention limits the number of node synchronizations that may be performed by a given node to prevent this attack. This limitation may additionally be time limited so that a malicious node cannot disable a node from ever performing such a synchronization again in the future.
[0084] Also discussed above were many search based attacks that could be launched or caused by a malicious node. To eliminate or minimize the effect of such search based attacks, the system of the present invention provides two mechanisms. The first is randomization. That is, when a node is searching for an appropriate next hop to which to forward a search request (RESOLVE), it identifies a number of possible candidate nodes and then randomly selects one ID out of these candidate IDs to which to forward the RESOLVE. In one embodiment, three candidate nodes are identified for the random selection. The IDs may be selected based on a weighted probability as an alternative to total randomization. One such method of calculating a weighted probability that the ID belongs to a non-malicious node is based on the distance of the PNRP ID from the target ID. The probability is then determined as an inverse proportionality to the ID distance between that node and the target node. In any event, this randomization will decrease the probability of sending the RESOLVE request to a malicious node.
[0085] The second security mechanism that is effective against search based attacks utilizes the bit vector discussed above to maintain state information. That is, a node maintains information identifying all of the RESOLVE messages that it has processed for which a response has not yet been received. The fields that are used to maintain the state information are the target ID and the address list in the RESOLVE packet. This second field is used to ensure that the address list has not been modified by a malicious node in an attempt to disrupt the search. As discussed above with the other instances of bit vector use, the node generates a hash of these fields from the RESOLVE and sets the corresponding bitpos in the bit vector to maintain a history of the processing of that RESOLVE.
[0086] As illustrated in the simplified flow diagram of FIG. 6 , when a RESPONSE message is received 296 from another node, the fields in this RESPONSE message are hashed 298 to calculate the bitpos. The node then checks 300 the bit vector to see if the bitpos is set. If the bit is not set, meaning that this RESPONSE is not related to an earlier processed RESOLVE, then the packet is discarded 302 . If the bitpos is set, meaning that this RESPONSE is related to an earlier processed RESOLVE, the bitpos is reset 304 . By resetting the bitpos the node will ignore further identical RESPONSE messages that may be sent as part of a playback attack from a malicious node. The node then checks to make sure that all of the PACs in the RESPONSE message are valid 306 before processing the RESPONSE and forwarding it to the next hop. If any of the PACs are invalid 306 , then the node will reject 310 the packet.
[0087] The RESOLVE process mentions converting a RESOLVE request into a RESPONSE. This RESPONSE handling just discussed involves ensuring the RESPONSE corresponds to a recently receives RESOLVE, and forwarding the RESPONSE on to the next hop specified. As an example, assume that node P receives a RESPONSE packet S containing a target PNRP ID, a BestMatch PAC, and a path listing the address of all nodes which processed the original RESOLVE before this node, ending with this nodes own PNRP address. Node P acknowledges receipt of the RESPONSE with an ACK. Node P checks the RESPONSE path for its own address. Its address must be the last entry in the address list for this packet to be valid. Node P also checks its received bit vector to ensure that the RESPONSE matches a recently seen RESOLVE. If the RESPONSE does not match a field in the received bit vector, or if P's address is not the last address in the path list, the RESPONSE is silently dropped, and processing stops. P validates the BestMatch PAC and adds it to its local cache. If the BestMatch is invalid, the RESPONSE is silently dropped, and processing stops. P removes its address from the end of the RESPONSE path. It continues removing entries from the end of the RESPONSE path until the endmost entry has a flag set indicating a node which ACCEPTED the corresponding RESOLVE request. If the path is now empty, the corresponding RESOLVE originated locally. PNRP does an identity validation check on the BestMatch. If the identity validation check succeeds, the BestMatch is passed up to the request manager, else a failure indication is passed up. If the path is empty, processing is complete. If the path is not empty, the node forwards the RESPONSE packet to the endmost entry in the path list.
[0088] A need for a PNRP address certificate revocation exists whenever the published address certificate becomes invalid prior to the certificate expiration date (Validity/To field). Examples of such events are when a node is gracefully disconnecting from the P2P network, or when a node is leaving a group, etc. The revocation mechanism of the present invention utilizes the publishing of a revocation certificate. A revocation certificate has the Revoke Flag set, and the From date of the Validity field set to the current time (or the time at which the certificate is to become revoked) and the To field set to the same value as the previously advertised certificates. All the certificates for which all the following conditions are met are considered to be revoked: the certificate is signed by the same issuer; the ID matches the ID in the revocation certificate; the Address fields match the ones in the revocation certificate; the To date of the Validation field is the same as the To date of the Validation filed in the revocation certificate; and the From date of the Validation field precedes the From date of the Validation filed in the revocation certificate. Since the revocation certificate is signed, it ensures that a malicious node cannot disconnect anyone from the cloud.
[0089] The foregoing description of various embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Numerous modifications or variations are possible in light of the above teachings. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled. | 4y
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method of enhancing wind farm energy production by designing new wind turbines and retrofitting single rotor turbines with tandem counter rotating rotors in existing wind farms.
[0003] 2. Description of Prior Art
[0004] Most wind turbines use a single rotor system that offers simplicity, reliability and durability. Over the years, improvements have been made to enhance energy conversion efficiency of these single rotor systems. For example, the rotor blades are designed for higher aerodynamic efficiency, the transmission gears are built for low noise and higher power transmission efficiency, and the electrical generators are designed for low copper and iron losses. Despite these improvements, single rotor systems are able to convert only a small fraction of wind stream energy into electrical energy and the remaining wind energy is lost without being harnessed. Since energy-rich wind farms are limited commodities, these sites must be efficiently used to maximize their energy production capacity.
[0005] In 1926, Albert Betz estimated that the maximum wind power conversion efficiency of a single rotor system could be as high as 59% if the axial velocity across it could be reduced by ⅔ (Ref.1). In 1942 another investigator, Walter Just, used two rotors in tandem and estimated the power conversion efficiency of two rotors could be increased to 64% (Ref.2). Just also used the same axial velocity change criterion across two rotors, but did not account for the energy content of the tangential velocity component. Since the ⅔ rd velocity reduction criterion is difficult to enforce in practice, most wind turbines hardly achieve 40 percent of power conversion efficiency.
[0006] The primary reason for this was illustrated by Charles Gordon Curtis as early as in 1896 (Ref.3). Curtis had realized that it was difficult to achieve large changes in enthalpy (velocity) across a single rotor. Therefore, he used the principle of velocity compounding with multiple rotors in tandem on a common shaft and estimated the energy conversion efficiency to be around 75 to 85%. It took 13 years for Curtis' idea to be accepted by the industry. Finally, in 1903 General Electric funded Curtis to build the first American 500 kW steam turbine, which became a landmark invention in power generation.
[0007] A number of patents have tried to increase the energy production of wind turbines. U.S. Pat. No. 5,419,683 to Peace discloses a method of installing plurality of wind turbines on chimneys, towers or the like. Two rotors having their horizontal axes were mounted back to back on a ring that turns about the chimney. The primary concept of this invention is to utilize existing tall structures to mount plurality of wind turbines and to reduce the need for wind farms.
[0008] The authors of this invention built several contra-rotating wind turbine models and conducted wind tunnel and field tests. The studies have shown that the contra-rotating rotors in tandem could convert additional 30 to 40 percent of wind energy into electrical energy compared to a corresponding single rotor system (Ref. 7). These studies led Appa to the develop multiple versions of contra-rotating wind turbine concepts to enhance wind power conversion efficiency. He has been issued two U.S. Pat. Nos. 6,127,739 and 6,278,197 B1, for his work. In addition, a third U.S. patent based on the application Ser. No. 09/894345, has recently been accepted.
[0009] It was with the knowledge of the foregoing state of the technology that the present invention has been conceived and is now reduced to practice. The contra-rotating rotors system in tandem, embodied by this invention is different from all the devices reviewed above. Furthermore, this system can be easily retrofitted to existing single rotor systems without significant alterations in the design.
REFERENCES
[0010] 1. Betz, A., Wind-Energie und Ihre Ausnutzung durch Windmuehlen, Vandenhoeck & Ruprecht, Goettingen 1926.
[0011] 2. Just, W., and Noetzlin, U., Section II: “Leistungsbetrachtungen ueber die verschiedenen Arten von Windmotoren (Strahitheorie),” Denkschrift 7; Arbeiten der Reichsarbeitsgemeinschaft, “Windkraft,” im Geschaeftjahr 1942-1943, Berlin-Steglitz, 12. Jul. 1943.
[0012] 3. “The First 500 Kilowatt Curtis Vertical Steam Turbine, New Port Rode Island, February 1903,” An International Historic Mechanical Engineering Landmark, Jul. 23, 1990, published by American Society of Mechanical Engineers.
[0013] 4. Kari Appa, “Jet Assisted Counter Rotating Wind Turbine”. U.S. Pat. No. 6,127,739, Oct. 3, 2000.
[0014] 5. Kari Appa, “Contra-Rotating Wind Turbine System”. U.S. Pat. No. 6,278,197 B1, Aug. 21, 2001
[0015] 6. Kari Appa, “Jet Assisted Hybrid Wind Turbine System”, (in Pending, Jc996 U.S. PTO 09/894345, submitted Jun. 28, 2001) now allowed and issuance fee has been paid.
[0016] 7. Kari Appa, “COUNTER ROTATING WIND TURBINE SYSTEM,” April 2002, Final Report Submitted to California Energy Commission.
SUMMARY OF THE INVENTION
[0017] The present invention is designed to enhance wind farm energy production with the use of contra-rotating wind turbines. The electrical energy production is directly related to Farm Power Density (FPD), a parameter introduced in this invention to describe the efficiency of a wind farm. FPD is defined as the electrical power produced with respect to area. It can be described in terms of megawatts per square kilometer (MW/km 2 ) or megawatts per acre (MW/acre). In order to maximize FPD, each turbine must not only provide a high power conversion efficiency, but also occupy minimal area of the wind farm. Turbines that have large rotor diameters although may produce adequate power, they occupy a greater area, thereby limiting the FPD.
[0018] Computation of Wind Farm Power Density:
[0019] Consider a wind farm measuring 1000×1000 meters in the wind stream direction. The required spacing between turbines can be calculated as follows:
[0020] Spacing in lateral direction=mD
[0021] Spacing in wind direction=nD
[0022] in which D is the diameter of the rotor and m and n are spacing constants depending on the aerodynamic characteristics of the rotor.
[0023] The number of turbines (N) in a kilometer square farm can then be determined:
N= 10 6 /( m×n×D 2 ) (1)
[0024] Then the wind farm power density (FPD) is given by,
FPD=N *(π D 2 /4)* p =(π*10 6 )/(4 mn)* p (watts/km 2 )
or
FPD =(π/4 mn)* p (MW/km 2 ) (2)
[0025] where, p is the rotor power density in watts/m 2 .
[0026] The wind farm power density, as shown in Equation (2) is not directly related to the rotor diameter, but to turbine spacing (m, n) and the rotor power density. Since spacing parameters m and n are fixed by the aerodynamic performance considerations, the wind farm density is then directly related to the rotor power density p. If a novel approach is used to increase the rotor power density, then it is possible to enhance the wind farm power production and its revenue. Such a novel approach is discussed next.
[0027] Power Density of a Dual Rotor System:
[0028] To achieve higher rotor power density, the authors of this invention built several configurations of the contra-rotating wind turbine system and conducted both wind tunnel and field tests. Detailed discussions of the study are presented in a report prepared for the California Energy Commission (Ref. 7). A typical example of the contra-rotor system is presented in FIG. 1, which shows the erection process of a contra-rotating wind turbine system at Oak Creek Energy Systems field test facility, Mojave Calif.
[0029] [0029]FIG. 2 shows the measured electrical power output by the windward rotor 1 and the leeward rotor 2 . The net power output is shown as the sum of the power from rotor 1 and rotor 2 . The net power, in FIG. 2, is seen to be 30 to 40 per cent more than that produced by the single rotor system. FIG. 3 further illustrates achievable contra-rotor power coefficient or the conversion efficiency factor at various wind speeds. The power coefficient is a measure of wind power conversion efficiency of a wind turbine. The net rotor power coefficient of a contra-rotating system is again, seen to be 30 to 40 per cent higher than that of a single rotor system. Especially at low rotor speeds, such as in the case of large utility scale wind turbines, the power coefficient is seen to exceed 0.72, whereas Betz's theoretical estimation for a single rotor is limited to 0.59 (practical achievable efficiency=0.4). This study suggests that the wind stream behind the first rotor carries significant amount of energy, which is available for conversion. This improvement could increase profit to the utility providers by millions of dollars per year.
[0030] Said method of increasing wind farm power production comprises:
[0031] 1. plurality of contra-rotating wind turbines having;
[0032] 2. a pair of contra-rotating rotors with their blade angles set to rotate in opposite directions,
[0033] 3. a larger leeward rotor with its plane of rotation set further back from the yaw axis to provide self aligning characteristics,
[0034] 4. an electrical generator driven by a pair of contra-rotating rotors,
[0035] 5. a pair of planetary gears that couple low speed rotors and the high speed generator shaft,
[0036] 6. a light duty yaw servomotor,
[0037] 7. an emergency braking device,
[0038] 8. a shaft adapter needed to transmit power from the contra rotating leeward rotor,
[0039] 9. a mast to support the wind turbine assembly and other accessories.
[0040] This invention suggests three ways of incorporating the counter rotating system in a wind farm to increase its power production:
[0041] 1. Dual Wind Turbines in Tandem:
[0042] This approach uses two wind turbines assembled back to back in tandem such that their rotors spin in opposite direction to each other. This concept can readily be used to retrofit existing wind farms in place of single rotor systems.
[0043] 2. Single Generator Having Dual Wound Armature Coils:
[0044] A single induction generator could be driven by two contra-rotating rotors. Most utility scale generators are provided with dual wound armatures so that the same unit can be used in low wind and high wind seasons to generate energy efficiently with reduced copper and iron losses. This unit can be retrofitted with two contra-rotating rotors to produce more energy using both sets of windings as needed.
[0045] 3. Direct Drive Induction Generator:
[0046] There is the provision to use direct drive generators without the need of gearboxes but requiring only an adaptor that couples the counter-rotating leeward rotor to the generator shaft so that two rotors could drive the same generator.
[0047] 4. Peripherally Mounted Jets:
[0048] There is the provision to use small jet engines (not shown) mounted at the blade tips to produce constant level of power during no wind or low wind conditions without the need for auxiliary power generating units.
[0049] Other features and benefits of the invention will become apparent in the following description taken in conjunction with the following drawings. It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory but are not to be restrictive of the invention. The accompanying drawings which are incorporated in and constitute a part of this invention, illustrate one of the embodiments of the invention, and together with the description, serve to explain the principles of the invention in general terms. Like numerals refer to like parts throughout the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] The foregoing aspects and other features of the present invention are explained in the following description, taken in connection with the accompanying drawings, wherein:
[0051] 1. Title of the Drawings
[0052] [0052]FIG. 1 is a perspective view of a contra-rotating wind turbine system being erected at test site,
[0053] [0053]FIG. 2 is the plot of power curves of single rotor and contra-rotating wind turbine units including theoretical predictions,
[0054] [0054]FIG. 3 is the plot of power coefficients of individual rotors and the net power coefficient of the contra-rotating system,
[0055] [0055]FIG. 4 is a typical configuration of a contra-rotating system comprising dual generators in tandem for improving wind farm energy production,
[0056] [0056]FIG. 5 is a typical configuration of a contra-rotating system comprising a single induction generator for improving wind farm energy production,
[0057] [0057]FIG. 6 is another configuration a contra-rotating system comprising a direct drive induction generator for improving wind farm energy production without the use of gearboxes.
2 REFERENCE NUMERALS
[0058] [0058] 10 a perspective view of dual generator wind turbine system
[0059] [0059] 11 windward rotor
[0060] [0060] 12 leeward rotor
[0061] [0061] 13 generator
[0062] [0062] 15 disc brake
[0063] [0063] 16 standard planetary gear having opposite input and output shaft rotation
[0064] [0064] 17 planetary gear having input and output shaft rotation in the same direction
[0065] [0065] 18 mast
[0066] [0066] 19 swivel base mount including the assembly of yaw servo and braking system
[0067] [0067] 20 denotes wind direction
[0068] [0068] 21 denotes direction of windward rotor
[0069] [0069] 22 denotes direction of leeward rotor
[0070] [0070] 23 windward rotor shaft
[0071] [0071] 24 leeward rotor shaft
[0072] [0072] 25 an adapter that changes the shaft rotational direction, used in direct drive generators for receiving power from contra-rotating rotors
[0073] [0073] 30 a perspective view of a contra-rotating wind turbine using induction generator
[0074] [0074] 40 a perspective view of a contra-rotating wind turbine using single direct drive (induction or permanent magnet) generator
[0075] [0075] 41 direct drive induction generator
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0076] The novel features believed characteristic of this invention are set forth in the appended claims. The invention itself, however, may be best understood and its objects and advantages best appreciated by reference to the detailed description below in connection with the accompanying drawings.
[0077] Referring now to FIGS. 4, 5 and 6 , there are shown three alternate perspective views of the contra-rotating wind turbine systems 10 , 30 and 40 incorporating the features of this invention for efficient use of wind farms to produce more power. Although the present invention will be described with reference to three embodiments shown in the drawings, it should be understood that the present invention could be embodied in many alternate forms or embodiments. In addition, any suitable size, shape or type of elements or materials could be used.
[0078] In FIG. 4, the wind turbine apparatus 10 is seen to include two rotor assemblies 11 , 12 two alternators 13 , an upright mast 18 supporting the turbine assembly base 19 including front and rare rotor gear boxes 16 . The leeward (downwind) rotor blades 12 are generally longer than the upwind rotor blades 11 and its hub is placed farther downstream from the vertical axis so that the system can self align to the wind as the wind changes its direction. The self-aligning feature results from larger leeward rotor drag and longer lever arm from its plane of rotation. Consequently, a light duty servomotor is sufficient to position the system aligned to the wind. Two disc brakes 15 are provided on the low speed rotor shafts 23 , 24 to shut down the system for servicing or in high-speed wind conditions. The arrow 20 denotes the wind direction, while arrows, 21 and 22 denote the rotational direction of the front and rear rotors respectively.
[0079] Certain communities that are far removed from accessible grid power source, a self-sustaining wind farm could be established by the use of small jet engines (not shown) mounted at the tip of the blades of rotors 11 and 12 to drive the generator during low wind or no wind conditions. Detailed discussion of this innovation is disclosed in a forth-coming US patent issued to Appa (Ref. 6).
[0080] In FIG. 5, is seen an alternate arrangement using a single generator 13 driven by two contra-rotating rotors 11 , 12 . The slowly spinning windward rotor 11 is coupled to the gear boxes 16 , generally of a planetary type. The high-speed end of said gearbox is coupled to the windward end of the generator shaft. The leeward end of the generator shaft is coupled to the high-speed end of a specially designed gear box 17 , while the low speed end of said gearbox is coupled to said leeward rotor. Once again, the subassemblies comprising rotors, generator, gear boxes and servo control units are arranged in such a way that the mass center lies slightly towards the downwind direction to render the self aligning feature of the contra-rotating wind turbine system and is guaranteed to be statically and dynamically stable. Once again said jet assisted hybrid configuration can also be implemented with this system.
[0081] [0081]FIG. 6 shows still another alternative arrangement of the tandem rotors 11 , 12 that drive a specially designed low speed direct drive generator 41 . The slowly spinning windward rotor 11 is directly coupled to the windward end of the generator shaft 23 . While the leeward end of the generator shaft 24 is first coupled to an adapter 25 , which in turn is coupled to the leeward rotor 12 . Once again, the subassemblies comprising rotors, generator, and servo control units are arranged in such a way that the mass center lies slightly towards the downwind direction so that the self aligning feature of the contra-rotating wind turbine system is guaranteed to be statically and dynamically stable. Said jet assisted hybrid configuration can also be implemented with the direct drive generator system.
[0082] Let us now consider the theoretical aspects of the invention, which demonstrates the benefits of contra-rotating tandem rotors in improving wind farm energy production and revenue at reduced cost.
[0083] The contra-rotating wind turbine system though looked into never went beyond paper work. The main reason could be that by extending the rotor diameter the same extra power could be produced without the need for a complex configuration. This may hold true for a single tower in an open field, but it is not the best way to maximize the efficiency of an energy-rich wind farm.
[0084] For an energy rich wind farm, which is a rare commodity, its full utilization becomes a very demanding factor. Energy production and revenue depends on wind farm power density (i.e. Megawatts per square kilometer or acre). If large diameter rotors are used, there will be fewer rotors (since 5 to 8 diameter spacing limits number of rotors) per acre resulting in no extra power. Hence, the tandem rotor arrangement helps to increase farm power density. Consequently, more power and revenue can be produced from the same wind farm. A brief discussion is presented next.
[0085] Wind Farm Power Density Analysis:
[0086] The present invention introduces a new terminology, “Farm Power Density or FPD as an acronym,” which denotes a measure of wind energy utilization of a wind farm. FPD is defined as mega watts per kilometer square, (MW/km 2 ). Consider a wind farm measuring 1000 meters wide and 1000 meters long in the wind stream direction. Let, mD and nD be the wind turbine spacing in lateral and longitudinal directions respectively, where D is the diameter of the rotor in meters.
[0087] Then, the number of turbines that can be installed in a kilometer square farm is,
N= 10 6 /(mn D 2 ) (1)
[0088] The wind farm power density is then given by,
P=N *(π D 2 /4)* p =(π*10 6 )/(4 mn)* p watts per km 2 .
Or
P =(π/4 mn)* p mega watt/km 2 (MW/km 2 ) (2)
[0089] where, p is the rotor power density in watts/m 2 .
[0090] The wind farm power density, as shown in Equation (2) is not directly related to the rotor diameter, but its spacing (m, n) and the rotor power density, p. The turbine spacing (m, n) is primarily a fixed quantity based on the aerodynamic characteristics of the rotors. Thus, it is seen that the wind farm power density is directly proportional to the rotor power density; p. If a novel approach is used to increase the rotor power density, then it is possible to enhance the wind farm power production and its revenue. Such a novel approach is discussed next.
[0091] Power Density of Contra Rotating Rotor by Field Tests:
[0092] In a recent study funded by the California Energy Commission under Grant No. 51809A/00-09, a contra rotating wind turbine model was built (FIG. 1) and the concept feasibility was demonstrated by field-tests. FIG. 2 summarizes the field test data in terms of power curves derived from two rotors. A theoretical analysis using the elementary blade theory as well as the wind stream power data are also shown for comparison with the field test results. The field test data are seen to agree well with the blade theory prediction up to wind speeds less than 16 mph. At higher speeds the blades might have stalled and hence the departure. FIG. 3 shows the power coefficient (a measure of power conversion efficiency) distribution for each rotor and the net power coefficient. The rear rotor power coefficient is seen to be in excess of 40% of first rotor power. Especially at low rotor speeds, the net power coefficient is seen to be around 72%, which is 13% higher than Betz's prediction of a single rotor case (Ref.1), and 8% higher than Jest's two-rotor momentum theory (Ref. 2). In general, the leeward rotor is seen to produce more than 40% of power at slow rotor speeds. This fact suggests that the velocity compounding by contra-rotation is seen to be more beneficial to utility scale mega watt wind turbines that turn slowly at 16 to 20 rpm. In that case, we may expect even better than 40% power enhancement. Thus, the contra-rotating tandem rotor wind turbine system has demonstrated that the rotor power density is 30 to 40 per cent more than that of a single rotor system. Since from equation 2 the wind farm power density is directly proportional to rotor power density, the wind farm power production and revenue could be increased by 30 to 40 per cent with the tandem rotor arrangement. Thus, the power density of the contra-rotating wind turbine is given by,
p (contra rotor)=1.4* p (single rotor) (3)
[0093] With this amount of energy produced in a wind farm, the retrofit cost could then be recovered in 3 to 5 years.
[0094] Another interesting observation of these field tests was that the well-known buffeting phenomena did not occur. One possible reason could be that the leeward rotor running in opposite direction might have swept away the vortices. Thus, the anticipated blade vibration may have been avoided.
[0095] From the foregoing, consider some of the advantages of the proposed wind turbine system over the known single rotor system:
[0096] 1. these innovations disclosed here are expected to increase the wind farm energy production by 30 to 40 per cent more than similar single rotor units,
[0097] 2. dual tandem rotor assembly is expected to reduce stress levels on the supporting structure due to torque load balancing and counter weighting rotor loads,
[0098] 3. the dual rotor system posses naturally self aligning stability characteristics,
[0099] 4. jet assisted hybrid wind turbine system is self sustaining unit requiring no auxiliary power system,
[0100] 5. Buffeting phenomenon is seen to be alleviated due to contra-rotation of the vortices.
[0101] It should be understood that the foregoing description is only illustrative of the invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances, which fall within the scope of the appended claims. | 4y
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a controller for a battery powered electric vehicle, and more particularly to a controller suitable for an electric car.
2. Description of the Related Art
For a vehicle using a battery (secondary battery) such as an electric car, it is possible for the vehicle to become incapable of running owing to exhausting of charge of the battery during driving.
Therefore, in the past, in order to prevent inoperability of the vehicle, the remaining amount of electric power in its battery is monitored to suppress the amount of electric power consumed when the discharge progresses to a certain amount. A technology is proposed in, for example, Laid-Open No.4-183206 (1992), Japanese Patent Application where a small capacity motor, separate from the main motor, is provided to drive an electric vehicle, and the drive motor is switched from the main motor to the small capacity motor to continue running when the voltage of the battery decreases owing to the progress of discharge.
The technology described above has the following disadvantages due to an increase in the weight of the vehicle, increase in the complexity of the construction, adverse influence owing to over-discharge of the battery, and a change in driving feeling of the vehicle, which are not taken into account.
Firstly, in the conventional technology, the electric vehicle required to mount a large capacity battery by its nature has to additionally mount another motor. Therefore, the conventional technology is opposed to the main design criterion of an electric vehicle that it be as light as possible to lengthen the running distance with a single battery charge, by effectively utilizing the limited capacity of the battery.
Secondly, in order to assure safety in a vehicle of such a type, for example in exiting a railroad crossing or the like, the vehicle must have capability of driving with a large torque for a short time, even if the battery is exhausted in a carotene degree during running on an ordinary road. In the conventional technology, it is difficult to maintain safety because the drive system is switched to a motor driving with a small torque, and the vehicle cannot cope with the situation. Thirdly, in the conventional technology, the switching of motors for driving the vehicle causes a noticeable change in handling characteristics of the vehicle, which can be unpleasant to the driver. The handling of the vehicle is deteriorated, since the running performance decreases in a step-down shape after the switching of the motors.
Fourthly, in the conventional technology, when the voltage of the battery decreases below a certain value, an electric power converting means for controlling electric power cannot output a desired power in some cases. When the vehicle continues to be driven using the small capacity motor in these instances, the battery is over-discharged, which deteriorates its performance and shortens its life.
SUMMARY OF THE INVENTION
The object of the present invention is to provided a controller for an electric vehicle which, when the remaining amount of electric power of the battery decreases, can limit electric power consumption by the vehicle motor without giving an unpleasant feeling to the driver, can drive the vehicle with a large torque for a short time, can obtain a sufficient running distance with a single battery charge, and can prevent the over-discharge of the battery.
According to a first embodiment of the present invention, the object described above can be attained by providing a controller which comprises a voltage detecting means for monitoring the terminal voltage of the battery and determining whether the terminal voltage is lower than a preset first comparison voltage; time detecting means for measuring the time elapsed from the point when the battery terminal voltage falls below the first present voltage, and for determining whether the elapsed time exceeds a first preset time period; and calculating means for producing a torque limiting command signal which decreases to a set lower limit at a given decreasing rate starting at the time when the battery terminal voltage falls below the first comparison value. The torque of the motor for driving the vehicle is controlled using either the torque command signal produced by operation of the accelerator pedal or the torque limiting command signal, whichever has the smaller value.
Further, according to a second feature of the invention, after generation of the torque limiting command signal, operation of electric power converting means for supplying electric power to the motor for driving the vehicle is stopped when elapsed time after the terminal voltage of the battery falls below a preset second comparison voltage exceeds a second preset time period.
Furthermore, according to a third feature of the present invention, the torque limiting command signal is cancelled when the operating amount of the accelerator operation inputting means becomes zero.
The voltage of the battery detected with the voltage detecting means is compared with an arbitrary preset comparison voltage. If the voltage of the battery is lower than the preset comparison voltage, the duration of this state is measured. If it continues for an arbitrary first preset time period, it is concluded that the remaining battery charge is small, and the torque of the motor is gradually decreased at a rate based on the torque limiting command signal.
As the result, the torque of the motor is decreased and the electric power demand on the battery is decreased. Therefore, the voltage of the battery is not rapidly decreased, and hence the vehicle can continue running.
As the battery is further discharged, the battery becomes over-discharged even if the vehicle is driven with decreased motor torque. In order to prevent such over-discharging, the voltage of the battery is further compared with a second comparison voltage. If the voltage of the battery remains below the second comparison voltage for the second preset time period or more during the torque limiting state of the motor, operation of the electric power converting means for supplying electric power to the motor is stopped to prevent over-discharging of the battery.
When the vehicle is required to be accelerated or run faster due to some change in the running condition while the motor is being driven under a state of limited torque with the voltage of the battery being near the limit value, the motor torque limitation is released by stepping off the accelerator once. Although the voltage of the battery decreases by depressing the accelerator again, it takes a certain time to detect this state. Therefore, the vehicle can be accelerated or driven with a high load if necessary since it is possible to generate a motor torque required for the acceleration within the time period.
After a certain time elapses, operation for limiting the torque of the motor is performed as described above to suppress to decrease the voltage of the battery.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a block diagram showing the construction of an embodiment of a controller for an electric vehicle in accordance with the present invention;
FIG. 2 is a control block diagram of an embodiment in accordance with the present invention;
FIG. 3 is a flow chart explaining the operation of torque limiting process in an embodiment in accordance with the present invention;
FIG. 4 is a time chart explaining the operation of torque limiting operation in an embodiment in accordance with the present invention;
FIG. 5 is a time chart explaining the resetting operation of torque limiting process in an embodiment in accordance with the present invention;
FIG. 6 is a flow chart explaining the operation of stopping process in accordance with the present invention; and
FIG. 7 is a time chart explaining the operation of stopping process in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
A controller for an electric vehicle according to the present invention will be described in detail below, referring to an embodiment shown in the accompanying drawings.
FIG. 1 shows an embodiment where the present invention is applied to an electric vehicle comprising an electric power converting means having an inverter to control an induction motor for driving the vehicle.
In FIG. 1, the main battery 16 (secondary battery) has a rated capacity corresponding to the performance required for the vehicle. The battery terminals are connected to input terminals of an electric power converting means 11, which converts direct current electric power into three-phase alternating electric power necessary for driving an induction motor 14 for driving the vehicle. The electric power converting means has semiconductor power elements 13 composing an inverter, and a voltage detecting circuit 12 which detects the terminal voltage of the main battery 16 and transmits a detected voltage signal 20 to a control means 4.
The control means 4 incorporates a micro-computer 5, a speed detecting circuit 10, a drive signal generating circuit 6, a gate block circuit 7, an interface circuit 8, and an electric power source circuit 9.
An encoder 15 for speed detecting is provided in the motor 14, and the speed detecting circuit 10 receives the signal from the encoder 15 and transmits it to the micro-computer 5 as a detected speed signal 24.
The drive signal generating circuit 6 generates a drive signal 23 which drives the semiconductor power elements 13 in the electric power converting means 11 in response to a driving command signal 22 calculated by the micro-computer 5 based on a signal from the interface circuit 8 and the detected speed signal 24 received from the speed detecting circuit 10.
The gate block circuit 7 is controlled by a gate block signal 19 output from the micro-computer 5 to selectively interrupt transmission of the drive signal 23 to the electric power converting means 11. The drive signal is transmitted when the gate block signal 19 is in a high level, and the drive signal is interrupted when the gate block signal is in a low level.
The interface circuit 8 performs input processing for external signals such from an accelerator (an accelerator operation inputting means) 1, a drive range switch 2, and a brake switch 3, and transmits them to the micro-computer 5.
The accelerator 1 has a foot operated accelerator pedal of the type commonly used in cars, which generates an accelerator operation signal corresponding to the degree of depression of the accelerator, and an acceleration-off signal 49 when the pedal is returned to a resetting position.
The drive range switch 2 is operated when selection is performed on forward running, or backward running and inputs a switching signal required for determining the rotating direction of the motor 14 to the control means 4. The brake switch 3 inputs a signal required for generating a braking torque of the motor 14 to a braking means 4 when the brake pedal is depressed.
The electric power source circuit 9 produces an electric power having a voltage necessary for operating the control means 4 from the direct current electric power supplied from an auxiliary battery 18 separately provided from the main battery 16.
The auxiliary battery 18 is for back-up, and is charged with the main battery 16 through a DC--DC converter 17.
Control operation with the control means 4 mainly composed of the micro-computer 5 will be described below, referring to the control block diagram of FIG. 2.
Initially, an accelerator operation signal from the accelerator 1 is input to a torque function generating block 25. At the same time, a detected motor speed signal 26 is also input to the torque function generating block 25. Therein a torque command signal 27 expressing a driving torque generated by the motor 14 is calculated based on the two kinds of the data. The calculated torque command signal 27 is then input to a limiting processing block 28, to limit the torque if necessary, according to a limiting process explained hereinafter.
The processed torque command signal 27' is input to a speed control block 29 and an exciting current function generation block 33. At the same time, the detected motor speed signal 26 is also input to the speed control block 29.
A speed difference signal 30, calculated and output by the speed control block 29, is input to a torque current calculation block 31, and a command signal of torque current 32 used for vector control is output from the torque current calculation block.
On the other hand, in the exciting current function generation block 33, a command signal of magnetic flux current 34 corresponding to the torque command signal 27' is calculated and output. The command signal of magnetic flux current 34 is input to a magnetic flux controlling and calculating block 35, which performs magnetic flux response control to output exciting current command signal 36 which is input to a vector calculation block 53.
The calculated command signals of torque current 32 and exciting current 36, together with the detected motor speed signal 26 are input to a slip frequency calculation block 37 to calculate a slip frequency command signal 52 which is input to a vector calculation block 53.
The vector calculation block 53 generates signals required for controlling the electric power converting means 11 (FIG. 1) based on the torque current command signal 32, the exciting current command signal 36 and the slip frequency command signal 52.
The detected motor speed signal 26 is calculated in and output by a motor speed calculation block 38 based on a motor speed signal (motor encoder pulses) 39. The motor speed signal 39 externally input is identical with the signal 24 in FIG. 1.
A detected voltage signal 42 is output from a voltage detecting block 41, based on the detected voltage signal (voltage signal) 40 externally input. The detected voltage signal 40 is identical with the signal 20 in FIG. 1.
The detected voltage signal 42 is input to a voltage comparator 43 to be compared with a preset threshold voltage (the first comparison voltage).
If the threshold voltage is higher than the detected voltage signal 42, a first limiting judgment flag 44 and a second limiting judgment flag 45 are output (at a high level).
The first limiting judgement flag 44 is input to a first timer processing block 47 (detecting timer 1), which counts the time while the first limiting judgement flag 44 remains at the high level. When the counted time exceeds a first preset time period, a torque limiting command signal 46 is generated and transmitted to the limiting processing block 28, where it. The smaller of these two signals is employed as the command signal for operation, to output it as the torque command signal 27'.
The second timer processing block 48 (detecting timer 2) receives the signals of the second limiting judgment flag 45, and counts the time while the second limiting judgment flag 45 remains at the high level. When the counted time exceeds a second preset time period, a gate block signal 19 is generated and transmitted to the gate block circuit 7 (shown in FIG. 1) to stop control of the electric power converting means 11.
Referring to FIG. 2, in order to interrupt the output of the driving command signal from the vector calculation block 53 even in a software-form, the gate block signal 19 is supplied to the gate block processing block 54 to cut off the transmission of the command signal.
Description will be made below of the process in FIG. 2 from the voltage comparing processing block 43 to the first timer processing 47 where the torque limiting command signal 46 is produced, referring to FIG. 3.
In step 301, the voltage V B of the main battery is detected based on the detected voltage signal 40.
Next, in step 302, an accelerator reset flag is checked, and if it is in a state equivalent to a release of the accelerator (that is, in the low level), processing proceeds to step 303 to reset the first limiting flag, and to step 304 to reset the torque limiting command signal to a maximum value. Thereafter, in step 305 the timer counter 1 for detecting time is cleared to complete the processing.
On the other hand, if the accelerator reset flag is in a state indicative of depression of the accelerator (in the high level), processing proceeds to step 306 to check the first limiting flag. (If the first limiting flag has been set, a limiting operation is being performed).
Where the first limiting flag is cleared, processing proceeds to step 307 to compare the detected voltage value V B with the first comparison voltage V 1 .
If V B is larger than the first comparison voltage V 1 , processing proceeds to step 303, and the limiting operation is released, since it is concluded that the terminal voltage of the main battery 16 is not so lowered even with the accelerator depressed. On the other hand, if the detected voltage value V B is smaller than the first comparison voltage V 1 , it is concluded that the terminal voltage of the main battery 16 is lowered when the accelerator is depressed, and processing proceeds to step 308 to add 1 (one) to the timer counter 1 to detect the time during which the voltage is kept low. Next, in step 309, the value in the timer counter 1 is checked, and if it is larger than C 1 , the first limiting flag is set in step 310 and the limiting operation mode is commenced in step 311, since the time during which the terminal voltage is kept low exceeds the first preset time period t 1 .
On the other hand, if it is determined in step 309 that the value in the timer counter 1 is smaller than C 1 , processing proceeds to step 311 to calculate a torque limiting command signal for limiting the torque of the motor (without setting the first limiting flag), since the time during which the terminal voltage has remained low does not exceed the first preset time period t 1 .
In step 312 it is determined whether the calculated torque limiting command signal is smaller than a lower limit value x 1 . If so, the process proceeds to step 313 to set the torque limiting command signal to the lower limit value x 1 in order to prevent the value from decreasing to an unnecessary extent.
The calculation of the torque limiting command signal in step 311 may be performed by simply subtracting 1 (one) from the maximum value for the torque limiting command signal, or by providing a predetermined pattern and decreasing the torque limiting command signal according to the pattern.
The lower limit x 1 for the torque limiting command signal may be a simple set value, or may be decreased depending on the number of past limiting operations which have been implemented.
The flow of the limiting process in FIG. 3 will be described below, referring to the time chart of FIG. 4, in which the accelerator is depressed at time T 0 as shown by line (a). Thereafter, a torque command signal for torque is generated as shown by line (d). When the opening of the accelerator becomes 100%, the command signal for torque also becomes 100%.
In a case where the main battery 16 has been discharged to a great extent, the detected voltage signal V B decreases as shown by line (b). (Line (c) in FIG. 4 expresses the current I B Of the battery 16.) At time T 1 , V B becomes lower than the first comparison voltage value V 1 , and the timer counter 1 starts to count time. During this period the torque continues to be generated at 100% as shown by the line (d).
When the count value in the timer counter 1 reaches C 1 at time T 2 (that is, the time during which the voltage is below V 1 exceeds the first preset time period t 1 ), the first limiting flag is set as shown by line (e) at the time T 2 and reduction of the torque limiting command signal commences as shown by line (f). That is, after the time T 2 , the torque limiting command signal is shifted to a decreasing state, and decreases smoothly with a given ratio as shown by the line (f).
The command signal which is actually used to control the motor is determined by selecting the smaller value as between the torque command signal given by the opening of the accelerator and the torque limiting command signal given by the calculation of the limiting process. Therefore, in the result, the torque command signal becomes smaller than the command signal given by the opening of the accelerator, as shown by the line (d). Then, after a certain period has elapsed, the torque limiting command signal is set to a constant minimum value (min value) at time T 3 as shown by the line (f), and hence the torque command signal also becomes a constant.
Therefore, according to this embodiment, the discharging current I B is limited depending on the discharge state of the main battery 16, independently of the opening of the accelerator at that time. As a result, the voltage again increases, and the discharge rate of the main battery 16 is moderated. Accordingly, the vehicle can continue to run, while effectively utilizing the capacity of the battery to extend the running distance, though the running torque is low under such a condition.
Since the torque command signal at time T 2 is not changed abruptly (in a step-shape) but decreases gradually, an unexpected change in the torque accordingly does not occur and the driving feeling (vehicle handling) is not deteriorated.
Further, since a high torque can be attained within a short period even in the time duration t 1 after the voltage of the battery is decreased below the judging voltage V 1 , the vehicle can cope with an emergency operation such as exiting a railroad crossing within the time duration to attain sufficient safety.
In other words, according to the present invention, when the accelerator is depressed farther under a condition where the remaining charge of the battery is decreased and the voltage is lowered, decrease in the voltage is detected to limit the magnitude of torque. Therefore, even if the accelerator is depressed farther in order to increase the output power of the motor under the condition of small remaining charge in the battery, the torque command signal is limited against the opening of the accelerator to suppress the voltage drop of the battery. Since the vehicle continues to be driven in a low torque state (and accordingly with a low produced torque itself even if the accelerator is depressed farther), the capacity of the battery can be fully utilized without decreasing its voltage.
After the limiting operation has been repeated several times, the remaining charge in the battery performing plural times of the limiting operation] is, of course, less than that at the first time of the limiting operation. In this embodiment, the limiting operation may be adapted to the remaining charge of the battery, since the lower limit for the torque limiting command signal may be further reduced relative to the lowered limit in the past.
FIG. 5 is a time chart showing the operation of resetting the limiting process (that is, exiting from a limiting processing state) by an acceleration-off. The acceleration-off means a state where the depression of an accelerator pedal is nearly zero, that is, a state where the accelerator pedal is in the returned or unactuated position.
In this embodiment, as in that described above, when the accelerator pedal is depressed an accelerator opening signal is output from the accelerator 1 in FIG. 1 to input to the torque function generating block 25, and an acceleration-off signal 49 is output from the accelerator 1 when the accelerator pedal is in the returned position. The acceleration-off signal 49 is input to the reset judging block 50, to reset the accelerator resetting flag 51 when the acceleration-off signal 49 is output.
Therefore, when the processing in FIG. 3 is performed while the acceleration-off signal is output, the process proceeds from step 302 to step 303. In this case, after resetting the first limit judging flag, the torque limiting command signal is set to the maximum value in step 304 as described above. Thus, when the processing is in a limiting state, resetting of the limiting process is performed by an acceleration-off as shown in FIG. 5.
In FIG. 5, the acceleration-off takes place at time T 4 when a limiting process is being implemented, after the time T 3 in FIG.
In the limiting process state, before the time T 4 , the torque limiting command signal is decreased to the minimum limit value as shown by line (f) of FIG. 5. Therefore, the torque command signal is lower than 100% owing to the torque limiting command signal as shown by line (d) even if the opening of the accelerator is 100%.
When the acceleration-off takes place at the time T 4 , the limiting process is discontinued, the first limit flag is cleared, and the torque limiting command signal is reset to 100% as described above.
Thereafter, when the accelerator pedal is again depressed at, for instance, time T 5 , the torque command signal is arbitrarily controlled to correspond to the opening of the accelerator as shown by the line (d) since the torque limiting command signal is set to 100%. The command signal may become 100%.
If the remaining charge of the battery at this point is small, the detected voltage value V B decreases as shown by line (b), and if the detected voltage value falls below a threshold of the first comparison voltage V 1 at time T 6 , the controlling state is once again shifted to the limiting process.
By decreasing the magnitude of the torque limiting command signal, the voltage V B is recovered to continue operation.
Therefore, according to this embodiment, even if the control once enters in the limiting operation due to a decrease in the battery voltage, and the torque command signal cannot be increased by stepping the accelerator deeper, maximum torque can be produced for a time duration of at least t 1 by returning the accelerator pedal once to its unactuated position. As a result, even when the remaining charge of the battery is decreased, large torque can be obtained for a short period of time, to accelerate the vehicle by repeatedly stepping on and off the accelerator pedal.
Further, according to the invention, by increasing the time for the subtracting calculation of the torque limiting command signal in the limiting process, a driver can drive the vehicle without experiencing a rapid decrease in the torque. Since a natural limiting operation can be attained as described above, a pleasant driving feeling can be realized.
It should be noted that if torque limiting is directly performed by detecting voltage change of the battery as in the conventional manner instead of employing the present invention, the following cyclic process will occur.
The torque is limited because of the voltage decrease. →The voltage is reset because of the limiting of torque. →The torque is increased because of the recovering of the voltage and hence the voltage decreases. →The torque is again limited because of the voltage decrease. →. . . .
Thus, there arises an oscillation in the torque. On the other hand, according to the present invention, since the torque does not increase even when the voltage is fully recovered by limiting the torque unless the accelerator pedal is returned, occurrence of such oscillation can be suppressed.
Description will be made below on the flow of processing from the voltage comparator 43 to the gate block signal 19, through the first timer process 47 explained using FIG. 2, referring to the flow chart of FIG. 6.
As the control enters into the processing shown in FIG. 6, similar to the limiting operation of FIG. 3, the terminal voltage V B of the main battery 16 is detected and set as a variable in step 614. In step 615, the variable V B is compared with the second comparison voltage V 2 . If V B is larger, it is concluded that the terminal voltage of the main battery 16 is not decreased, and the process proceeds to step 616, in which the second limit judging flag is cleared. The timer counter 2 for measuring elapsed time is then cleared in step 617, and in step 621 the gate block signal is set to the high level, so as to continue the operation of the electric power means 11.
On the other hand, if it is determined that V B ≦V 2 in step 615, it is concluded that the terminal voltage of the main battery 16 is decreased, and the process proceeds to step 618 to add count 1 to the timer counter 2 in order to measure the duration of the voltage drop. The counting value C 2 of the timer counter 2 is then compared with a preset value of the second judging time t 2 in step 619. If C 2 is larger than t 2 (that is, the state where the terminal voltage of the main battery 16 is below the second judging voltage V 2 continues for longer than the second judging time t 2 ), the process proceeds to step 620, in which the gate block signal is set to the low level in order to stop generating the command signal for driving the electric power converting means 11 and cut off generation of the command signal through software.
After step 620 is executed, the processing is brought into an infinite loop state to be interlocked so that other process cannot be performed, since the vehicle cannot continue to run any more.
Although in this embodiment the stopping of processing may be performed in connection with the limiting process operation as described above, the judgment and the process for stopping of processing may be separately performed.
As to the first comparison voltage V 1 for judging the voltage drop in the limiting process operation and the second comparison voltage V 2 for judging the voltage drop in the stopping process operation, if the relationship V 1 <V 2 is satisfied, then the operation can be performed in order of the limiting operation and then the stopping operation.
According to the invention, when the voltage is so lowered that normal operation is not performed even if the torque is limited through the limiting operation due to decrease in the remaining charge of the battery, operation of the electric power converting means is stopped. Therefore, over-discharge and damage of the battery can be prevented.
FIG. 7 is a time chart showing the operation stopping process. As the accelerator is depressed (changed from OFF-state to ON-state) at time T 0 as shown by line (a), a torque command signal is generated corresponding to the opening of the accelerator as shown by line (d). If the remaining charge of the main battery 16 is small at this point due to discharge (that is, the depth of discharge of the main battery is deep), the detected voltage V B decreases as shown by line (b). When the detected voltage V B decreases to the threshold value of the first comparison voltage V 1 at time T 1 , the time counter 1 starts counting-up to measure elapsed time as shown by line (h). During this period, the torque command signal is not limited by the torque limiting command signal yet. Therefore, the torque command signal remains at 100% as shown by the line (d).
If the depth of discharge of the main battery 16 is comparatively shallow, the voltage drop stops at a certain value. If the depth of discharge of the main battery 16 is deep, however, the voltage drops further. Such a state leads to over-discharge of the battery, and affects its life-time.
Since the voltage drops further when the depth of discharge of the main battery 16 is deep (as assumed in FIG. 6), the voltage ultimately decreases to a level below the second comparison voltage V 2 at time T 12 , as shown in line (b), and the time counter 2 starts to count as shown by line (i).
During this same period, the time counter 1 also continues counting as shown by the line (h). When the counting value C 1 of the time counter 1 reaches the first preset time period t 1 at time T 2 , the torque limiting command signal is decreased to decrease the torque command signal in order to recover the voltage as described above. However, where the depth of discharge is deep and the remaining charge is small, the voltage does not recover after the time T 2 as shown by the line (b). Therefore, when the detected voltage value V B remains below the second comparison voltage V 2 even with the command signal of torque decreased, it is judged that the discharge will go deeper to cause over-discharge.
When this happens, the time counter 2 continues to count as shown by the line (i), and when the count reaches the value C 2 corresponding to the second preset time period t 2 at the time T 22 , the gate block signal is turned off (that is, changed to the low level) to stop the operation of the electric power converting means 11.
According to this embodiment, when the depth of discharge of the main battery 16 is very deep, and the remaining charge is extremely small so that the voltage does not recover even if the command signal of torque is limited, the operation of the electric power converting means 11 is stopped. Therefore, the main battery 16 is not discharged further, and accordingly the running distance of the vehicle can be extended to the limit of the battery capacity without possibility of over-discharge.
As a result, the danger of shortening the life-time of the battery due to over-discharge can be eliminated.
According to the present invention, since the limiting of torque due to decrease in the remaining charge is performed without giving any unpleasant feeling to a driver during running of an electric vehicle, a pleasant driving feeling can be realized.
Further, according to the present invention, since a high torque can be attained for a short period even after the remaining charge of the battery is decreased and the control has entered the torque limiting state, the vehicle can certainly display a driving performance sufficient to prevent danger, and attain high safety.
Furthermore, according to the present invention, since discharge of the battery can be suppressed by limiting the torque while maintaining running capability, the capacity of the battery can be effectively utilized. Thereby, the running distance with a single battery charge can be substantially extended and over-discharge of the battery can be prevented. Thus, the service time of the battery can be extended and the running cost of the vehicle can be lessened.
Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example, and is not to be taken by way of limitation. The spirit and scope of the present invention are to be limited only by the terms of the appended claims. | 4y
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CROSS REFERENCE TO RELATED APPLICATIONS
This application claims benefit as a continuation-in-part of U.S. patent application Ser. No. 13/622,648 filed Sep. 19, 2012, which application is incorporated by reference herein.
FIELD OF THE INVENTION
The present disclosure relates generally to mattresses and cushioning devices for home and/or hospital use, and more particularly to a telescoping spring assembly usable as a component of a mattress or cushioning device.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 6,996,865 to Sabin describes a mattress structure in which a support assembly comprises a support plate having an array of mounting holes each receiving a respective telescoping spring assembly. In U.S. Pat. No. 6,996,865, various embodiments of the spring assembly are identified by the reference numerals 20, 120, 220, 320, and 420. The various spring assembly embodiments are telescoping spring assemblies in the sense that each has an inner member arranged to be axially slidable within an outer tubular member, and a mechanical spring is arranged within the inner and outer members to bias the members in an extension direction. The Sabin patent teaches that it is desirable to preload the spring to control firmness. In order to achieve preload, Sabin discloses the use of a spacer (e.g., spacers 28, 128, and 228) engaging an end of the spring and one of the tubular members, wherein the spacer has an axial length chosen to provide a desired preload. The spring assemblies mounted on the support plate may have different preload characteristics achieved by using spacers of different lengths to vary the firmness of the mattress in different support zones.
Efforts to commercialize the invention in U.S. Pat. No. 6,996,865 have been met with certain design challenges. A significant challenge has been the fact that the preload applied to the coil spring is transmitted to the inner and outer tubular members. Under this design, the inner and outer members are forced into a fully extended condition (absent external loading) and are prevented from separating by engagement of opposing shoulder surfaces on the external wall surface of the inner member and on the internal wall surface of the outer member. As a result, the frictional engagement between the shoulders of the inner and outer members causes the spring assembly to be “sticky” at times, and the spring assembly does not always react as intended when an external load is first applied. Moreover, after an external load is removed from a compressed spring assembly, the biasing force of the coil spring immediately pushes the outer member in the extension direction, and the ensuing engagement of opposing shoulder surfaces on the inner and outer members generates a popping sound that is disruptive to a person at rest.
SUMMARY OF THE INVENTION
The present invention solves both of these challenges, and does so by eliminating the need for a spacer of special length in each spring assembly.
The present invention is embodied by a spring assembly comprising a tubular outer member including a support end and an open receiving end opposite the support end, and a tubular inner member including an insertion end and a mounting end opposite the insertion end, wherein the insertion end of the inner member is received through the open receiving end of the outer member such that the outer member is telescopically movable relative to the inner member in a compression direction and an extension direction opposite from the compression direction. The spring assembly further comprises a coil spring arranged to bias the outer member in the extension direction relative to the inner member. In accordance with the present invention, the spring assembly comprises a fabric sleeve fitted about an inner diameter and an outer diameter of the coil spring, wherein the fabric sleeve is closed at its opposite ends to apply a compression preload to the coil spring. The fabric sleeve prevents transmission of the preload to the tubular members to eliminate the problems of stickiness and noise when the spring assembly changes length.
The present invention may also be embodied as a spring assembly including a tubular outer member including a support end and an open receiving end opposite the support end. The assembly may also include an inner member, including an insertion end and a mounting end opposite the insertion end. The insertion end can be received by the outer member through the open receiving end of the outer member, the outer member being telescopically movable relative to the inner member in a compression direction and an extension direction opposite from the compression direction. A coil spring can be arranged to bias the outer member in the extension direction relative to the inner member. A first bumper insert may be arranged at a first end of the coil spring, and a second bumper insert may be arranged at a second end of the coil spring. A preload member can extend from the first bumper insert to the second bumper insert. The preload member may be configured to apply a compression preload to the coil spring.
In another embodiment, the present invention is embodied as a method of making a spring assembly. A tubular outer member including a support end and an open receiving end opposite the support end can be provided. An inner member including an insertion end and a mounting end opposite the insertion end can be provided. A coil spring may be arranged to bias the outer member in the extension direction relative to the inner member. A first bumper insert may be arranged at a first end of the coil spring. A second bumper insert may be arranged at a second end of the coil spring. A preload member can be arranged to extend from the first bumper insert to the second bumper insert. The preload member can be configured to apply a compression preload to the coil spring.
BRIEF DESCRIPTION OF THE DRAWING VIEWS
Features and advantages of embodiment(s) of the present disclosure will become apparent by reference to the following detailed description and drawings, in which:
FIG. 1 is a perspective view of a telescoping spring assembly formed in accordance with an embodiment of the present invention;
FIG. 2 is an exploded view of the telescoping spring assembly shown in FIG. 1 ;
FIG. 3 is an exploded view of a support cap subassembly of the spring assembly shown in FIG. 1 ;
FIG. 4 is an end view of the support cap subassembly shown in FIG. 3 ;
FIG. 5 is an exploded view of a mounting subassembly of the spring assembly shown in FIG. 1 ;
FIG. 6 is an end view of the mounting subassembly shown in FIG. 5 ;
FIG. 7 is an end view of a coil spring of the telescoping spring assembly, wherein the coil spring is enclosed in a fabric sleeve;
FIG. 8 is a perspective view of a preload member; and
FIG. 9 is an end view of the preload member of FIG. 8 .
DETAILED DESCRIPTION OF THE INVENTION
A telescoping spring assembly formed in accordance with the present invention is shown in FIG. 1 and identified generally by reference numeral 10 . Spring assembly 10 comprises a tubular inner member including an insertion end and a mounting end opposite the insertion end. The mounting end is characterized by a fitting 13 for insertion into a corresponding mounting hole of a plate (not shown), whereby an array of closely spaced spring assemblies 10 may be formed to provide the core of a mattress as taught by the aforementioned U.S. Pat. No. 6,996,865, the entire disclosure of which is incorporated herein by reference. Spring assembly 10 also comprises a tubular outer member 14 including a support end 15 and an open receiving end opposite the support end. As may be seen in FIG. 1 , the insertion end of inner member 12 is received by outer member 14 through the open receiving end of the outer member. As may be understood, outer member 14 is telescopically movable relative to inner member 12 in a compression direction to shorten the overall length of spring assembly 10 , and in an extension direction opposite from the compression direction to extend the overall length of the spring assembly.
Reference is made now to FIG. 2 . Spring assembly 10 further comprises a coil spring 16 arranged to bias outer member 14 in the extension direction relative to inner member 12 . In the embodiment shown, one end of coil spring 16 bears against a bumper insert 18 disposed at the insertion end of inner member 12 , and an opposite end of coil spring 16 bears against another bumper insert 20 disposed in outer member 14 axially adjacent to support end 15 .
FIGS. 3 and 4 show outer member 14 and bumper insert 20 in further detail. As may be seen, outer member 14 includes a plurality axially extending ribs 24 spaced at regular angular intervals about an internal wall of the outer member adjacent the open receiving end of the outer member. In the embodiment shown, bumper insert 20 includes a generally rigid plastic insert on which an elastically deformable bumper piece 26 is mounted to face inner member 12 , and a bumper spring 28 is disposed on the opposite side of bumper insert 20 to engage support end 15 of outer member 14 . Bumper spring 28 may be chosen to have greater stiffness than coil spring 16 . FIGS. 5 and 6 show inner member 12 and bumper insert 18 in further detail. Inner member 12 includes a circumferential shoulder 30 around an external wall of the inner member adjacent the insertion end of the inner member. In the embodiment shown, bumper insert 18 includes a generally rigid plastic having a lip 32 sized to engage the insertion end of inner member 12 such that bumper insert 18 remains located at the insertion end of inner member 12 . An elastically deformable bumper piece 34 is mounted on bumper insert 18 to face bumper insert 20 . A bumper spring 36 is disposed on the same side of bumper insert 18 so that it also faces bumper insert 20 . Bumper spring 36 may be chosen to have greater stiffness than coil spring 16 . The bumper inserts 18 and 20 , and the bumper springs 36 and 28 , provide stiffer cushioning as spring assembly 10 approaches a fully compressed condition to prevent “bottoming out” under very heavy external loads.
Airflow into and out of spring assembly 10 during telescoping volume changes is allowed by passages through the mounting end of inner member 12 and the support end of outer member 14 , however these passages are not visible in the drawing views. Such airflow is also allowed by passages 38 through bumper inserts 18 and 20 , and by gaps 40 between ribs 24 in outer member 14 .
Axial separation of outer member 14 and inner member 12 may be prevented unless an intentionally large separation force is applied. In the embodiment shown, axial separation is prevented by engagement of circumferential shoulder 30 with the ends of ribs 24 closest to support end 15 . However, as will be understood from the description below, when coil spring 16 is properly preloaded, outer member 14 freely floats on the coil spring such that the ends of ribs 24 are slightly spaced from engagement with shoulder 30 to avoid the sticking problem mentioned in the background section.
In accordance with the present invention, spring assembly 10 additionally comprises a fabric sleeve 22 fitted about an inner diameter and an outer diameter of coil spring 16 , wherein fabric sleeve 22 is closed at its opposite ends to apply a compression preload to coil spring 16 . The compression preload applied to spring 16 decreases the length of the spring enough so that the ends of ribs 24 on outer member 14 do not engage shoulder 30 on inner member 12 . For example, the compression preload may be chosen to provide a distance of about one-eighth of an inch between the ends of ribs 24 and shoulder 30 when spring assembly 10 is at rest and free of external loading.
Fabric sleeve 22 may be formed about coil spring 16 in a variety of ways. In one way, the sleeve begins as two separate generally rectangular sheets of non-stretch fabric, one to fit about the outer diameter of coil spring 16 and the other to fit about the inner diameter of coil spring 16 . If coil spring 16 is a variable stiffness coil spring wherein the inner and outer diameters vary along the axial length of the spring, then the outer sheet must fit around the largest outer diameter and the inner sheet must fit within the smallest inner diameter. Each sheet is folded over onto itself and a lengthwise seam is formed along overlapping portions of the sheet to provide a generally tubular sleeve portion of appropriate diameter depending upon whether the sleeve portion is internal or external. The external and internal sleeve portions are then arranged around the outer diameter and inner diameter of coil spring 16 , respectively a first circumferential seam may then be made near one end of coil spring 16 to secure the external sleeve portion to the internal sleeve portion. A preload is applied to coil spring 16 by compressing the coil spring to a predetermined axial length, and then a second circumferential seam is made near the second end of the compressed coil spring to secure the external sleeve portion to the internal sleeve portion, thereby confining the coil spring in a preloaded condition.
In another way of fitting fabric sleeve 22 to coil spring 16 , the fabric sleeve begins as a single generally rectangular sheet of non-stretch fabric in excess of two times the intended length of preloaded coil spring 16 . The single sheet is folded over onto itself and a lengthwise seam is formed along overlapping portions of the sheet to provide an elongated tubular sleeve portion of appropriate diameter to fit about the outer diameter of coil spring 16 . The coil spring is inserted into the elongated tubular sleeve portion and the sleeve is inverted (turned inside-out) and fed through the interior of the coil spring. As a result, one end of the spring will be confined against the folded sleeve, and the other end of the spring will be near an open end where the two unconnected ends of the fabric sleeve are aligned with one another. A preload is applied to coil spring 16 by compressing the coil spring to a predetermined axial length, and then a circumferential seam is made to attach the aligned ends of the fabric sleeve to one another, thereby closing the open end to confine the coil spring in a preloaded condition.
Those skilled in the art will understand that seams may be formed by sewing or by ultrasonic welding, and that the amount of excess fabric material needed to form sleeve 22 may depend on the seam technology used.
At least two fabrics have been found particularly suitable for use in forming fabric sleeve 22 . The first is Sparmont 900 needle punched fabric, which is recommended for coil springs with spring rates of two pounds per inch or less. The second is SW400 sonic welded fabric, which is recommended for coil springs with spring rates from two to four pounds per inch. Both fabrics are supplied by NuTex Concepts located at 2424 Norwood Street, Lenoir, N.C. 28645. Of course, other fabrics may be used.
As will be understood, the use of fabric sleeve 22 in accordance with the present invention provides important benefits. Fabric sleeve 22 maintains the preload on coil spring 16 so that engagement between inner member 12 and outer member 14 is not necessary for this task. In this way, the problem of “stickiness” is solved, and the popping sound when the spring assembly returns to its extended position is eliminated. Moreover, preload can be determined by selecting a coil spring 16 having a spring rate and free length such that the coil spring provides a desired preload when compressed by fabric sleeve 22 to a predetermined, known length. The spring rate of coil spring 16 may be a variable spring rate to provide lesser firmness during initial compression of spring assembly 10 under external loading, followed by somewhat greater firmness as the spring assembly compresses further. The performance of each spring assembly can be individualized without the need for spacers of different lengths as taught by the prior art. Also, the fabric sleeve helps to dampen and absorb acoustic energy to provide quieter spring assembly performance apart from elimination of the popping sound mentioned above.
As generally described above, the fabric sleeve 22 can serve as a “preload member” to apply a compression preload to coil spring 16 . However, a compression preload may be applied with other types of “preload members” that do not include a fabric sleeve fitted about the coil spring 16 . For example, FIGS. 8 and 9 show another example of a preload member 50 . FIG. 8 is a perspective view of a preload member. FIG. 9 is an end view of the preload member of FIG. 8 .
The preload member 50 may extend from bumper insert 18 to bumper insert 20 , and include a length 52 and ends 54 . The length may be made of a flexible material, such as a woven nylon or fabric material. The ends 54 can be made of a more rigid material, such as plastic. It is contemplated, however, that the preload member 50 can be made uniformly of a single material.
The preload member 50 may be located inside the diameter of coil spring 16 , for example, along approximately a center axis 16 A of the coil spring 16 . It is possible, for example, that the preload member 50 only extend along approximately center axis 16 A of the coil spring. In other words, it is possible that the preload member 50 is embodied as a single strand of material that extends between the bumper inserts 18 , 20 . In one embodiment, the preload member 50 extends through the airflow passages 38 of the bumper inserts 18 , 20 . The ends 54 may be protruded relative to the length 52 of the preload member 50 so as to prevent the ends 54 from sliding through the airflow passages 38 .
The preload member 50 can be shorter (e.g. have a length) that is less than the length of the coil spring because the preload member 50 may rest within a portion of the bumper insets 18 , 20 that extend into the coil spring 16 . Although the ends 54 are depicted as being located at an outer, opposite side of the bumper inserts 18 , 20 relative to the length 52 of the preload member 50 . However, it is contemplated that the preload member 50 may be glued or otherwise affixed to an inner side of the bumper inserts 18 , 20 .
Unlike the fabric sleeve 22 , which can provide a compression preload by itself, preload member 50 cooperates with bumper inserts 18 , 20 to apply a compression preload to the coil spring 16 . Furthermore, it is possible that the preload member 50 not touch the coil spring 16 in a rest state. However, in both instances (i.e. in using a preload member 50 or a fabric sleeve 22 ), the member applying the preload can generally extend between bumper insert 18 and bumper insert 20 . The preload member 50 may also have efficiencies over the fabric sleeve 22 such as being easier to produce, faster to install in a spring assembly 10 , and use less material.
While the invention has been described in connection with exemplary embodiments, the detailed description is not intended to limit the scope of the invention to the particular forms set forth. The invention is intended to cover such alternatives, modifications and equivalents of the described embodiment as may be included within the spirit and scope of the invention.
LIST OF REFERENCE SIGNS
10 Spring assembly
12 Inner member
13 Mount fitting on inner member
14 Outer member
15 Support end of outer member
16 Coil spring
16 A Center axis of coil spring
18 Bumper insert of inner member
20 Bumper insert of outer member
22 Fabric sleeve
24 Ribs along internal wall of outer member
26 Bumper piece on bumper insert of outer member
28 Bumper spring on bumper insert of outer member
30 Circumferential shoulder of inner member
32 Lip on bumper insert of inner member
34 Bumper piece on bumper insert of inner member
36 Bumper spring on bumper insert of inner member
38 Airflow passages
40 Gaps between ribs
50 Second embodiment of a preload member
52 Length of second embodiment of a preload member
54 Ends of second embodiment of a preload member | 4y
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CROSS-REFERENCE TO RELATED APPLICATIONS
This patent application is a division of U.S. patent application Ser. No. 10/510,711, filed Oct. 18, 2004, now U.S. Pat. No. 7,194,953, issued Mar. 27, 2007. That application was the U.S. National Phase, under 35 U.S.C. 371, of PCT/DE03/1157, filed Apr. 9, 2003; published as WO 03/08774A2 and A3 on Oct. 23, 2003 and claiming priority to DE 102 17 402.4 filed Apr. 18, 2002, and to DE 102 37 205.5 filed Aug. 14, 2002, the disclosures of which are expressly incorporated herein by reference.
FIELD OF THE INVENTION
The present invention is directed to a dressing on a cylinder, or on a transfer cylinder, as well as printing units of a printing press with the cylinder. At least one of the cylinders has a dressing having an elastic and/or compressible layer.
BACKGROUND OF THE INVENTION
A printing blanket is known from DE 691 07 317 T2, which consists of several layers and, in an extreme case, has a total thickness of from 0.55 to 3.65 mm. The modulus of elasticity of the several layers of cellular rubber lies between 0.2 to 50 MPa, or between 0.1 to 25 MPa. Because of the special structure of the printing blanket, and because of the properties of the several layers, a printing blanket is obtained which, when indented, does not tend towards lateral shifting or protuberances.
DE 19 40 852 A1 discloses a printing blanket for offset printing, which blanket has a total thickness of almost 1.9 mm. A modulus of shearing, in the form of tension at 0.25 mm deformation in case of a thickness of the printing blanket, is stated to be approximately 4.6, 1.9 or 8.23 kg/cm 2 . The goal, in this case, is to achieve a quick recovery after an indentation, as well as to achieve a narrow thickness tolerance.
CH 426 903 discloses an offset printing blanket in which customary indentation depths of 0 to 0.1 mm exist. An increase of the indentation from 0.05 to 0.1 mm requires, or has, at a result, a change in the surface pressure of approximately 20.6 N/cm 2 . This means that, in this range of indentation depth and with surface pressures of up to approximately 40 N/cm 2 , there would be a linearized “spring characteristic” with a rise of approximately 412 N/cm 2 /mm.
WO 01/399 74 A2 discloses printing units with two cylinders, which two cylinders work together in the placed-together position. A forme cylinder has an opening, in the area of its surface, in the form of an axially extending groove for use in fastening one end of one or of several printing formes. A transfer cylinder, which acts together with the forme cylinder in a contact zone, has an elastic rubber blanket in the area of its surface.
For the transfer of ink and other fluids between two cylinders of a printing press, recourse is regularly had to the material combination of hard-soft, for example in an inking and/or dampening unit, as well as in the practice of an offset printing method between printing group cylinders. The surface pressure required for ink transfer between the two cylinders is achieved by making an indentation in a resilient, such as, for example, an elastomeric layer, which may be a soft elastomeric cover/dressing, rubber blanket, or metal printing blanket, sleeve, by a cooperating cylinder with a surface which is incompressible and which is also inelastic, to a large degree.
Essential criteria for the uniform transfer of the fluid between the cylinders are a contact pressure, which is preset within narrow margins, as well as the constancy of the contact pressure. If fluctuations occur in the spacing distance between the cooperating cylinders, for example because of cylinder out-of-roundness or because of vibrations induced by interferences with the roll-off of the cylinders, the contact force, or the surface pressure, changes, and thus the transfer behavior of the fluid also changes. At locations with interrupted or with reduced contact, for example at the location of the plate or rubber blanket tensioning groove, the surface pressure, for example, changes periodically. This periodic change in surface pressure results in a vibration excitation of the printing cylinders. In the field of printing technology, this change in surface pressure is expressed by changes in the ink intensity in the resulting printed image. If, for example, the contact pressure has been permanently changed through exterior conditions such as longer wave interference, the danger of too faint or of too color-intensive printed products exists until the time of correction. These products are typically considered as waste products. If the contact pressure is dynamically changed because of vibrations, such as shorter wave interference, this change in contact pressure is expressed by the formation of visible stripes in the printed product.
SUMMARY OF THE INVENTION
The object of the present invention is directed to producing a dressing for, or on a cylinder, the arrangement of this cylinder in relation to a second cylinder, as well as to printing units of a printing press.
In accordance with the invention, this object is attained by the provision of a dressing on a surface on a cylinder having an elastic or compressible layer with a surface pressure as a function of an indentation. One of the cylinders, in a printing unit of two cylinders, and which has the elastic or compressible layer is a transfer cylinder. A contact width between the transfer cylinder and its cooperating cylinder is at least 10 mm and is at least 5% of the effective cylinder diameter. The indentation caused on the transfer cylinder surface may be at least 0.18 mm. At least one of the cylinders may have a dressing end receiving groove which has a width, with respect to the width of the contact zone, that is at most 1 to 3.
The advantages to be gained by the present invention reside, in particular, in that a reduced sensitivity to changes, or to fluctuations, in the contact pressure or surface pressure, is achieved, and that because of this, a high quality of the printed product can be achieved in a simpler manner and can be maintained. By the use of special dressings, by an optimized layout of the cylinders, as well as by their arrangement, it is possible to reduce the effects of any cylinder movements on ink transfer. In a particularly advantageous embodiment, with cylinders having narrow places of interrupted, or of reduced contact, the vibration excitation itself is moreover reduced.
By the embodiment of the dressing and/or by the arrangement of the cylinders in relation to each other, the transfer of the fluid between the two is considerably less affected. The same applies, for example, to interferences that are induced by changes in the process, such a changing speed, changing thickness of the material; of a web, bringing further cylinders into or out of contact to spacing deviations which occur as a result of inaccuracies in the course of making contact, such as stops, finite stiffness, or manufacturing tolerances; as well as to changes in the dressing thickness because of wear; i.e. longer wave vibrations and/or incomplete restoration after passing through the nip location; shorter wave or longer wave vibrations.
This is achieved, in particular, in that the dressing is configured in such a way, or the cylinder is produced with an appropriate dressing, that a dependence of the resulting surface pressure or contact pressure, in the course of a variation of the indentation, extends considerably flatter than is customary. A spring characteristic, i.e. an increase in dependence of the surface or contact pressure from the indentation, advantageously lies, at least in an advantageous range, for the indentation in the print-on position of at the most 700 (N/cm 2 )/mm.
An advantageous range of a relative indentation of the dressing, in the operating state or in the print-on position, lies between 5% and 10%, for example. However, ranges for setting the relative indentation, which ranges differ as a function of the two cylinders working together, can be preferred for achieving optimal results in view of the required transfer of the fluids, along with a simultaneously small effect of fluctuations.
In an advantageous embodiment of the present invention, the surface or contact pressure, in the print-on position, varies, at most, within a range of between 60 and 220 N/cm 2 . Or for various sub-ranges for fluids, such as, for example, printing inks, having greatly different rheological properties, and/or different printing methods, in particular in these ranges, or sub-ranges, the curve should meet the requirements made on the rise.
Up to the present, the width of the contact zone, which is being created by the pressure of the cylinders against each other in the nip, has, as a rule, been kept as narrow as possible. A widened nip location results in a higher linear force, and therefore results in increased static bending. However, this disadvantage is compensated for by the dressing in accordance with the present invention, or the cylinder arrangement. In an advantageous embodiment, a width of the nip location is, for example, at least 10 mm, and in particular, is greater than or equal to 12 mm. An advantageous surface or contact pressure can be achieved with this nip width.
For the case where a vibration is induced by an interference, such as, for example, by an interruption, on one of the surfaces of the cylinders which work together directly, or via a web, it is possible, by the construction of the dressing and/or by the arrangement of the cylinders in relation to each other, to also reduce the excitation of this vibration, or to reduce its amplitude. This applies, in particular, to an embodiment of the present invention wherein a width of the cylinder surface interruption, in the circumferential direction, has, at most, a ratio of 1:3 with respect to the width of the nip, or the imprint strip, caused by the indentation.
In general, the dressing, or the cylinder layer, permits the use of slimmer, or also longer print cylinders. These are cylinders in which a length of the cylinders is large in comparison with the diameter of the cylinder.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention are represented in the drawings and will be explained in greater detail in what follows.
Shown are in:
FIG. 1 , a schematic representation of the line forces between two cylinders while using a conventional dressing, in
FIG. 2 , a schematic representation of the line forces between two cylinders while using a dressing in accordance with the present invention, in
FIG. 3 , the measured surface pressure in a variation of the indentation, in
FIG. 4 , a first preferred embodiment of a printing unit in accordance with the present invention, in
FIG. 5 , a second preferred embodiment of a printing unit, in
FIG. 6 , a third preferred embodiment of a printing unit, in
FIG. 7 , a fourth preferred embodiment of a printing unit, and in
FIG. 8 , a schematic representation of a dressing with a support layer in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring initially to FIGS. 1 and 2 , a machine, for example a printing press, has cylinders 01 , 02 , which roll off on each other and which together form a nip location 03 , such as, for example, a cylinder gap 03 . In the case of a printing press, these cylinder 01 , 02 can be cylinders of an inking unit, a varnishing unit, or can be cylinders 01 , 02 of a printing unit. In the preferred embodiment of the present invention, that is represented in FIG. 1 , the cylinders 01 , 02 represent a forme cylinder 01 of an effective diameter D wPZ , and a transfer cylinder 02 of an offset printing unit. One of the cylinders 01 , 02 , for example the transfer cylinder 02 , has a dressing 05 or a cover 05 with a soft elastomeric layer 06 of a thickness “t” that is on the surface of a largely incompressible, inelastic cylinder core 04 of a diameter D GZK . The total thickness “T” of the dressing 05 is composed of, for example, the thickness “t” of the soft, elastomeric layer 06 , as well as a thickness of a support layer 10 , which support layer 10 is possibly connected with the layer 06 and which is substantially incompressible and inelastic, which support layer 10 may be, for example, a metal plate, shown, by way of example, in FIG. 8 . If the dressing 05 does not have an additional support layer 10 , the thickness “t” corresponds to the total thickness “T”. The layer 06 can be built up as an inhomogeneous layer 06 of several layers, which together have the required properties for the layer 06 . Together, the core 04 and the dressing or cover 05 , constitute an effective diameter Ds 24 wGZ of the transfer cylinder 02 . The effective diameter D wGZ of the transfer cylinder 02 is determined at the point of contact of the transfer cylinder 02 with the surface of the forme cylinder 01 which surface of the forme cylinder 01 is effective for the roll-off, and which possibly includes a dressing 08 , for example a printing forme 08 , applied to the surface of a forme cylinder base body 07 . The cylinder 01 with the hard surface can also be embodied as a counter-pressure cylinder 01 , which is working together with the transfer cylinder 02 . The specific embodiment of the layer 06 , as is explained in what follows, is not tied to the embodiments of the cylinders 01 , 02 as transfer and forme cylinders 01 , 02 , or to an embodiment of the cylinder 01 with a printing form 08 .
As a function of the spacing between the two cylinders 01 , 02 , i.e. as a function of their axial spacing distance A, the largely incompressible inelastic surface of the forme cylinder 01 “dips” or intrudes or penetrates into the soft layer 06 of the dressing or cover 05 on the transfer cylinder 04 and causes an indentation S in that soft or resilient layer 06 , in comparison to the undisturbed course of the layer 06 . Because of the restoring forces, a fluctuating or a changing indentation S, as a rule, leads to a fluctuating or to a changing surface or contact pressure P in the cylinder gap 03 , and causes the previously discussed problems in the quality of the ink transfer, and, in the, end, causes problems in the quality of the printed product.
A profile of a surface or contact pressure P in the nip 03 between the two cylinders 01 and 02 , using a conventional dressing, is schematically represented in FIG. 1 . The surface pressure P extends over the entire area of the contact zone wherein, at rest, at a height of a connecting plane V between the axes of rotation of the two cylinders, the surface or contact pressure P reaches a maximum surface pressure P max . During production, the location of the area of maximum pressure shifts toward the incoming gap side as a result of the viscous force portion. In a projection onto a plane E, which plane E extends perpendicularly with respect to the connection plane V, the contact zone, and therefore the profile, has a width B. The maximum surface pressure P max is ultimately responsible for the ink distribution, and must be set accordingly.
In comparison with FIG. 1 , FIG. 2 schematically shows the profile of the surface or contact pressure P in the case, in accordance with the present invention, of a greater indentation S, which simultaneously causes a widening of the width B. If it is now intended to achieve the maximum surface or contact pressure P max in spite of this increased width of the contact zone is, the integration of the surface or contact pressure P over the entire width B leads to an increase of a force between the two cylinders 01 , 02 .
The absolute size of the surface pressure P in the cylinder gap 03 , as well as its fluctuation when the indentation S varies, is substantially determined by a spring characteristic of the layer 06 used, or of the dressing 05 in which the layer 06 is used. The spring characteristic represents the surface or contact pressure P as a function of the indentation S. Some spring characteristics of customary dressings 05 , and in particular of printing blankets 05 with an appropriate layer 06 , are represented, by way of example, in FIG. 3 . The values have been determined in the laboratory at a quasi-static die test stand. They should be transferred, in a suitable manner, to values determined in another way.
It can be seen in FIG. 3 , that a rise Δ P/Δ S of the spring characteristic determines the fluctuation in the surface pressure P during the change of the indentation S, for example in the case of a vibration. With a variation Δ S of the indentation around a mean indentation value S, the size of a fluctuation Δ P of the required maximum surface pressure P max in the cylinder gap 03 around the mean surface pressure P is approximately proportional to the rise Δ P/Δ S of the spring characteristic at the location S. Thus, in connection with a dressing “a”, as depicted in FIG. 3 , for example, a reduction of the indentation S from −0.16 mm to −0.14 mm acts on the surface pressure P in the form of a reduction by approximately 50 N/cm 2 , and a reduction of the indentation S from −0.11 mm to −0.09 mm acts on the surface tension in the form of a reduction by approximately 25 N/cm 2 . A dressing “b” has a lesser rise, as also depicted in FIG. 3 .
Dressings 05 , which either as a whole, or whose layers 06 as such, have such a large rise A P/A S, in particular in the range of the required maximum surface pressure P max in the relevant pressure range, are called “hard” in what follows, those with a small rise Δ P/Δ S are called “soft”.
The dressing 05 , or the layer 06 , in accordance with the present invention are embodied as a “soft” dressing 05 or as a “soft” layer 06 . In contrast to a “hard” dressing 05 , or to a “hard” layer 06 , identical relative movements of the cylinders 01 , 02 , or of the change of the distance A, therefore lead to a lesser change of the surface or contact pressure P in case of a soft dressing 05 , and therefore lead to, or result in a reduction of the fluctuations in the ink transfer. Thus, the soft dressing 05 of the present invention results in lesser sensitivity of the printing process to vibrations and/or to deviations of spacings from a nominal value. With fewer changes in the surface pressure P because of relative movements of the cylinders 01 , 02 , with the use of soft dressings 05 , or with dressings 05 with a soft layer 06 , vibration strips in the printed product, for example, only become visible at larger vibration amplitudes.
In an advantageous embodiment of the present invention, the surface, or contact pressure varies, at most, within a range of between 60 and 220 N/cm 2 . In connection with fluids, for example with printing inks with greatly different rheologic properties, different ranges within the above mentioned range of the surface pressure can be preferable. Thus, the range of the surface pressure, in connection with wet offset printing; i.e. with printing using ink and dampening agent, varies between 60 and 120 N/cm 2 , and in particular between 80 to 100 N/cm 2 , for example, while in case of dry offset printing, with no dampening agent, and with only the application of ink to the forme cylinder the range of the surface or contact pressure varies between 100 and 220 N/m 2 , and in particular between 120 to 180 N/cm 2 , for example. In these ranges, in particular, the rise should meet the requirements for a rise.
The print-relevant range for the surface or contact pressure P max advantageously lies between 60 and 220 N/cm 2 . For fluids, for example with printing inks with greatly differing rheologic properties, different ranges within the above mentioned range of the surface pressure can be preferred. Thus, the range for wet offset printing varies, for example, between 60 and 120 N/cm 2 , and in particular from 80 to 100 N/cm 2 . This is represented in FIG. 3 . In case of dry offset printing the range varies, for example, between 100 and 220 N/cm 2 , and in particular from 120 to 180 N/cm 2 . Thus, in an advantageous embodiment, a soft dressing 05 , or its soft layer 06 , has, at least in the range of 80 to 100 N/cm 2 , a rise Δ P/Δ S of, for example, Δ P/Δ S<700 (N/cm 2 )/mm, and in particular Δ P/Δ S<500 (N/cm 2 )/mm. In the respective range for the surface or contact pressure P, the rise Δ P/Δ S should be smaller, by at least a factor of two, than is customary currently for dressings 05 in offset printing.
As schematically indicated in FIG. 2 , in an advantageous embodiment of the present invention, the layer 06 has a greater thickness “t”, or the dressing 05 has a greater total thickness “T”, than has been previously customary. The thickness “t” of the layer 06 , which is functional in respect to elasticity or compressibility, is for example 3.0 to 6.3 mm, and in particular is from 3.7 to 5.7 mm thick. Added to this elastic layer 06 is the thickness of one or several support layers 10 , which are substantially incompressible and inelastic, and which are possibly connected with the layer 06 , if desired, on the side of layer 06 facing the core 07 , which support layers 10 are connected with the layer 06 for the purpose of providing stability of shape and/or dimensions. This support layer 10 , or these support layers 10 , which is/are functionally effective for the shape stability, can also be arranged between the “soft” layers 06 . For example, support layer 10 can be embodied as sheet metal, in particular of high-grade steel, of a thickness of approximately 0.1 to 0.3 mm. If the support layer 10 is in the form of a woven material, it can be 0.1 to 0.6 mm thick, depending on the embodiment of the dressing 05 . In the case of several soft layers 06 , the thickness “t” of the soft layer 06 relates to a sum of the possibly several “partial layers”, which are functionally responsible for the above described characteristic of dependence of surface pressure/indentation, and to elasticity or compressibility. In that case, a dressing 05 with a soft layer 06 , together with a support layer or layers 10 , has a total thickness T of 3.5 to 6.5 mm, and in particular of 3.9 to 5.9 mm.
The “soft” dressing 05 or the “soft” layer 06 is preferably operated at a greater indentation S in comparison with customary or known indentations S, as schematically represented in FIG. 2 as comparison with FIG. 1 , i.e. the two cylinders 01 , 02 are put closer together in relation to their respectively effective, but undisturbed diameters D wGz , D wPZ . Because of this, an optimal maximum surface pressure P max is achieved in spite of a reduced rise Δ P/Δ S. In an advantageous embodiment, the placement of the cylinders 01 , 02 against each other is performed in such a way that the indentation S is at least 0.18 mm, is, for example, between 0.18 to 0.60 mm, and in particular is from 0.25 to 0.50 mm.
A relative indentation S*, i.e. the indentation S in relation to the thickness “t” of the layer 06 , without taking into consideration the particular embodiment of the cylinders 01 , 02 , lies, for example, between 5% and 10%, and in particular lies between 6% and 8%.
In an advantageous embodiment, a width B of the contact zone, in a projection perpendicularly to a connecting plane V of their axes of rotation, resulting from the indentation S of the layer 06 , is at least 5% of the undisturbed effective diameter D wGZ of the cylinder 02 with the layer 06 .
As described above, the embodiment and/or the arrangement of the “soft” dressing 05 is particularly advantageous, if one of the two cooperating cylinders 01 , 02 , or even if both of the cylinders have an interference 09 , 11 on their effective surface, which affects the rolling-off. This interference 09 , 11 , in the form of an interruption 09 , 11 , can be an axially extending joint of two ends of one or of several dressings 05 , 08 . In particular, the interference 09 , 11 can also be caused by an axially extending groove 09 , 11 for use in fastening of the ends of one or of several dressings 05 , 08 . This groove 09 , 11 has an opening toward the cylinder surface, through which opening the ends have been conducted. In its interior, the groove 09 , 11 can have a device for clamping and/or tensioning of the dressing 05 , 08 , or the dressings 05 , 08 .
In the course of cylinder 01 rolling over the groove 09 , 11 , or the grooves 09 , 11 of cylinder 02 , vibrations are induced. If, viewed in the circumferential direction, the width B 09 , B 11 of the groove 09 , 11 is greater than the width B of the contact zone, a vibration, with an increased amplitude, is induced during the passage of the groove 09 , 11 since, because of the above mentioned greater width B of the contact zone, a larger linear force acts between the two cylinders 01 , 02 . Yet, because of the greater linear force, the increase of the vibration amplitudes is less than the reduction of the sensitivity to vibrations because of the softness of the layer 06 , so that an overall reduction of the sensitivity to vibrations results.
It is of particular advantage to select the width B 09 , B 11 of the grooves 09 , 11 to be less than the width B of the contact zone. In this case, at least areas of the cooperatively acting surfaces are always supported on each other in the contact zone. In addition, a reduction of the size and a flatter course, or a widening of the pulse, results for the force of the beating excitation. Therefore, with narrow grooves 09 , 11 , the use of softer dressings 05 , or softer layers 06 , leads to a weakening and to a chronological lengthening of the groove beat.
In the case of the transfer cylinder 02 , the ends of a metal printing blanket can be arranged in the groove 11 . In this case, the layer 06 has been applied to a dimensionally stable support, for example to a thin sheet metal plate, whose beveled ends are arranged in the groove 11 . The groove 11 can be configured to be extremely narrow, for example having a width less than, or equal to 5 mm, and in particular having a width less than or equal to 3 mm. Also, in the case of the forme cylinder 01 , the groove 09 is structured, in an advantageous embodiment, with a width in the circumferential direction of less than or equal to 5 mm, and in particular with a width of less than or equal to 3 mm.
Conversely, because of the contact zone, or the imprint strip, which is larger in comparison with prior art contact zones, the permissible ratio B 09 :B, or B 11 :B is reduced. An embodiment is of particular advantage, wherein the width B 09 , B 11 of the groove 09 , 11 , in the area of its opening, or mouth, toward the surface of the core 04 , or the base body 07 , has, at most, a ratio of 1:3 in the circumferential direction in relation to the width B of the contact zone or the imprint strip formed by the indentation.
Preferably, the soft layer 06 has a reduced damping constant in comparison with customarily employed materials. In spite of higher loading and release speeds, occurring during roll-of because of the larger indentation S, no increased flexing heat is generated. Also, the layer 06 must be embodied in such a way that a sufficiently rapid restoration, or spring-back, into the initial position, takes place following the passage through the cylinder gap 03 so that, for example, the initial thickness is again present in the course of contact with an inking roller or with a further cylinder.
A printing unit 12 , which is configured in an advantageous manner with the layer 06 and which is embodied as a so-called double printing unit 12 , is represented in FIGS. 4 and 5 . The transfer cylinder 02 , which is assigned to the forme cylinder 01 , and which form a first cylinder pair 01 , 02 , cooperates with a counter-pressure cylinder 14 , that is also embodied as a transfer cylinder 14 , and which is also assigned to a forme cylinder 16 , via a material 13 to be imprinted, for example via a web 13 . All four cylinders 01 , 02 , 14 , 16 are each driven, mechanically independent of each other, by different drive motors 17 , as seen in. In a modification, the forme and transfer cylinders 01 , 02 , 14 , 16 are coupled in pairs and each pair is driven by a paired drive motor 17 , either at the forme cylinder 01 , 16 , at the transfer cylinder 02 , 14 , or parallel to the cylinders, all as seen in.
In a first preferred embodiment, the forme cylinders 01 , 16 and the transfer cylinders 02 , 14 are embodied as cylinders 01 , 02 , 14 , 16 of double circumference, i.e. as cylinders each with a circumference of substantially two upright printed pages, in particular two newspaper pages. The cylinders are configured with effective diameters D wGZ , D wPZ between 260 to 400 mm, and in particular between 280 to 360 mm. On the surface of the core 04 , each of the transfer cylinders 02 , 14 has at least one dressing 05 of a total thickness T of between 3.5 to 6.5 mm, and in particular between 3.9 to 5.9 mm. The rise Δ P/Δ S of the spring characteristic, at least in the print-relevant range, as discussed above, lies below 700 (N/cm 2 )/mm, and in particular lies below 500 (N/cm 2 )/mm. The forme and transfer cylinders 01 , 02 , 14 , 16 have been placed against each other in pairs in such a way that the width B of the contact zone between the forme and transfer cylinders 01 , 02 , 14 , 16 , in the position in which they are placed against each other, is from 14 to 25 mm, and in particular is from 17 to 21 mm. By the use of this configuration, the sensitivity of the printed product to vibrations and to inexact placement of the cylinders against each other has been minimized to a large extent. The individual drive mechanisms, in the form of drive motors 17 , aid this by the mechanical uncoupling.
In a second preferred embodiment of the present invention, which is not specifically represented, the forme cylinders 01 , 16 and the transfer cylinder 02 , 14 are embodied as cylinders 01 , 02 , 14 , 16 each of single circumference, i.e. as cylinders each with a circumference of substantially one upright printed page, and in particular of one newspaper page. These cylinders are structured with effective diameters D wGZ , D wPZ of between 150 to 190 mm. On the surface of the core 04 , the transfer cylinder 02 , 14 has at least one dressing 05 of a total thickness T of from 3.5 to 6.5 mm, and in particular of from 3.9 to 5.9 mm. The rise Δ P/Δ S of the spring characteristic, at least in the print-relevant range, as discussed above, again lies below 700 (N/cm 2 )/mm, and in particular lies below 500 (N/cm 2 )/mm. The forme and transfer cylinders 01 , 02 , 14 , 16 have been placed against each other in pairs in such a way that the width B of the contact zone between the forme and transfer cylinders 01 , 02 , 14 , 16 , in the position in which they are placed against each other, is from 10 to 18 mm, and in particular is from 12 to 15 mm.
In a third preferred embodiment, which is also not depicted, the forme cylinders 01 , 16 are embodied as cylinders 01 , 16 of single circumference with effective diameters D wPZ of between 150 and 190 mm, and the transfer cylinders 02 , 14 are embodied as cylinders 02 , 14 of double circumference with effective diameters D wGZ of between 260 to 400 mm, and in particular of from 280 to 350 mm. The transfer cylinders 02 , 14 each have at least one dressing 05 of a total thickness T of from 3.5 to 6.5 mm, and in particular from 3.9 to 5.9 mm, on the surface of the core 04 . The rise Δ P/Δ S of the spring characteristic, at least in the print-relevant range, as discussed above, again lies below 700 (N/cm 2 )/mm, and in particular lies below 500 (N/cm 2 )/mm. The forme and transfer cylinders 01 , 02 , 14 , 16 have been placed against each other in pairs in such a way that the width B of the contact zone between the forme and transfer cylinders 01 , 02 , 14 , 16 , in the position in which they are placed against each other is, from 12 to 20 mm, and in particular is from 15 to 19 mm.
A printing unit 19 in accordance with the present invention is represented in FIGS. 6 and 7 , which is either a part of a larger printing unit, for example a five cylinder, nine cylinder or ten cylinder printing unit, or which can be operated as a three cylinder printing unit 19 . Here, the transfer cylinder 02 works together with a cylinder 18 , which does not convey printing ink, for example a counter-pressure cylinder 18 , such as a satellite cylinder 18 . Now the “soft” surface of the transfer cylinder 02 works together with the “hard” surface of the forme cylinder 01 on the one side, and with the “hard” surface of the satellite cylinder 18 on the other side. In an embodiment, shown in FIG. 6 , where at least the transfer cylinder 02 and the satellite cylinder 18 are driven independently of each other, the one, or several satellite cylinders 18 have their own drive motor 17 , while the pair consisting of the forme and transfer cylinders 01 , 02 are mechanically coupled and are driven by a common drive motor. Alternatively, the forme and transfer cylinders 01 , 02 can be mechanically independent of each other, and each driven by its own drive motor 17 , as seen in FIG. 7 .
In a first embodiment in FIGS. 6 and 7 , the forme cylinder 01 , the transfer cylinder 02 and the satellite cylinder 18 are embodied as cylinders 01 , 02 , 18 , each of double circumference, and each with effective diameters D wGZ , D wPZ , D wSZ of between 260 to 400 mm, and in particular of from 280 to 360 mm. On the surface of the core 04 , the transfer cylinder 02 has at least one dressing 05 of a total thickness T of 3.5 to 6.5 mm, and in particular of 3.9 to 5.9 mm. The rise Δ P/Δ S of the spring characteristic, at least in the print-relevant range, as discussed above, lies below 700 (N/cm 2 )/mm, and in particular lies below 500 (N/cm 2 )/mm. The forme and transfer cylinders 01 , 02 , as well as the transfer cylinder 02 and the satellite cylinder 18 , have been placed against each other in pairs in such a way that the width B of the contact zone in the position in which they are placed against each other is from 14 to 25 mm, and in particular is from 17 to 21 mm.
In a second embodiment in FIGS. 6 and 7 , the forme cylinder 01 , the transfer cylinder 02 and the satellite cylinder 18 are embodied as cylinders 01 , 02 , 18 of single circumference, i.e. each with a circumference of substantially one upright printed page, in particular one newspaper page. They are structured with effective diameters D wGZ , D wPZ , D wSZ of between 150 to 180 mm, and in particular of between 130 to 170 mm. On the surface of the core 04 , the transfer cylinder 02 has at least one dressing 05 of a total thickness T of from 3.5 to 6.5 mm, and in particular of from 3.9 to 5.9 mm. The rise Δ P/Δ S of the spring characteristic, at least in the print-relevant range, as discussed above, again lies below 700 (N/cm 2 )/mm, and in particular lies below 500 (N/cm 2 )/mm. The forme and transfer cylinders 01 , 02 , as well as the transfer cylinder 02 and the satellite cylinder 18 , have been placed against each other in pairs in such a way that the width B of the contact zone, in the position in which they are placed against each other, is from 10 to 18 mm, and in particular is from 12 to 15 mm.
The changes implicit because of the greater softness, such as the greater indentation S, the changed roll-off behavior, the larger thickness t or T, and the line must be taken into consideration in the layout of the printing press. For example, a printing press operating with softer and thicker dressings 05 , or layers 06 , therefore has changed, and in particular has increased cylinder undercuts or roll-off blanket thickness, as well as changed gap dimensions when cylinders are placed against or away from each other due to blanket thickness, or indentation. Also, greater cylinder shift paths are required for the print-off position because of the larger indentation.
The above mentioned dressing 05 , or the layer 06 , is arranged, for example, in a printing unit with one or with several long, but slim cylinders 01 , 02 , 14 , 16 .
Thus, the forme cylinder 01 , 16 and the transfer cylinder 02 , 14 each have, for example, in the area of their barrels, a length, which corresponds to four or more widths of a printed page, for example a newspaper page. This width may be, for example from 1,100 to 1,800 mm, and in particular may be from 1,500 to 1,700 mm. The diameter D wGZ , D wPZ of at least the forme cylinder 01 , 16 is, for example, from 145 to 190 mm, and in particular is from 150 to 185 mm, which diameter, in circumference, corresponds substantially to a length of a newspaper page and is thus a “single circumference”. The device of the present invention is also advantageous for other circumferences in which a ratio between circumference and length of the cylinder 01 , 02 , 14 , 16 , 18 is less than or equal to 0.16, and in particular is less than 0.12, or is even less than or equal to 0.08.
In another embodiment of the printing unit, in accordance with the present invention the length of the barrels of the forme and transfer cylinders 01 , 02 , 14 , 16 is, for example, from 1,850 to 2,400 mm, and in particular is from 1,900 to 2,300 mm, and is dimensioned, in the axial direction, for receiving, for example, at least six side-by-side arranged upright printed pages in broadsheet format. In a variation of the invention, the diameter of at least the forme cylinder 01 , 06 lies, for example, between 260 and 340 mm, and in particular lies between 280 to 300 mm, and in another variation for example lies between 290 to 380 mm, and in particular is from 300 to 370 mm, which, in circumference, corresponds substantially to two lengths of a newspaper page and is thus a “double circumference”. A ratio of the diameter D wGZ , D wPZ of at least the forme cylinder 01 , 16 to its length here lies from 0.11 to 0.17, and in particular from 0.13 to 0.16.
While preferred embodiments of a dressing on a cylinder, or a transfer cylinder, as well as printing units of a printing press, in accordance with the present invention, have been set forth fully and completely herein above, it will be apparent to one of skill in the art that various changes in, for example the dressing material, the mechanisms used to secure the dressings to a cylinder, and the like could be made without departing from the true spirit and scope of the present invention, which is accordingly to be limited only by the following claims. | 4y
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BACKGROUND OF THE INVENTION
The present invention relates generally to check valves for passing fluids in one direction but preventing fluid flow in the opposite direction. More particularly, to a flapper check valve for use in fluid handling systems where corrosive products are pumped.
In the past, corrosive fluid handling systems requiring check valves have used ball type check valves. These ball check valves were of standard design and were constructed from metal parts. However, they require that their internal surfaces be coated with a thermoplastic or thermoset material that is impervious to the caustic product flowing in the pipeline. The thermoplastic material was bonded to the internal surfaces of the ball check valve through an expensive injection molding process. It was necessary to coat these surfaces to protect the metal parts of the valve from destruction from the caustic fluids. The ball that was used to check the back flow of the caustic fluids was usually made from tetrafluoroethylene (TFE), a material commonly known by the name TEFLON, a registered trademark of DuPont.
A major disadvantage of these prior-art ball check valves was that Teflon does not have memory, i.e. once the Teflon has been deformed, it tends to stay deformed. To check the backflow through the valve, the check ball is cradled in a seat that surrounds an internal opening that was part of the through passage of the valve. The ball, acting against the seat, formed the seal that prevented any back flow. Unfortunately, the ball often times is checked (driven against the seat by the fluid attempting to flow in the opposite direction) against the seat abruptly. Sometimes this abrupt check causes the seat to produce a ring or indentation in the ball. Eventually, the ball begins to lose its generally spherical shape as a result of the repeated checkings and begins to lose its ability to seal against the seat.
A solution to the problem to the Teflon ball wearing out from repeated checkings is to substitute a metal ball and metal seat made from an exotic and expensive metal alloy such as Monel (an alloy of stainless steel and nickel). These metal balls and seats are not coated with a thermoplatic material and eventually are destroyed by the caustic fluids although they tend to last longer than the Teflon balls.
Another disadvantage of ball check valves is that they must be mounted vertically to work properly. In a vertical orientation, the ball falls into the seat, due to gravity, when flow through the valve is zero. In a horizontal position, the ball moves into the seat only if there is reverse flow and, once a seal is formed, there is sufficient back pressure to hold the ball in the seat.
The disadvantages discussed above of ball type check valve are not present in flapper type check valves. The flapper seals against a flat surface and does not experience the deterioration to the sealing surfaces that the ball in the ball check valve does. Also, flapper check valves may be installed in any orientation.
While flapper type check valves are known in the art, workable designs for flapper check valves for use in fluid handling systems where corrosive fluids are involved have not been developed. Thus, it would be advantageous to provide a flapper type check valve for use in corrosive fluid handling systems where the internal check valve parts are impervious to the corrosive fluids. It would also be advantageous to provide a flapper check valve of either the flange or waffer design that was both inexpensive to manufacture and simple to service. It would also be advantageous to provide a streamlined flapper check valve where all parts of the valve were contained within a cylindrical metal sleeve having no cumbersome exterior bonnets to accommodate the hinged flapper. It would also be advantageous to provide a flapper check valve in which the flapper seals the through passage of the valve at a smaller back pressure than is normally required in valves of that type design without the need for a spring to urge the flapper against the sealing surface when the flow is zero.
SUMMARY OF THE INVENTION
In accordance with this invention, a streamlined flapper check valve is provided in which all of the internal components are constructed from a thermoplastic, thermoset or elastomeric (hereinafter thermoplastic) material impervious to corrosive fluids with which it will be used. A cylindrical stainless steel sleeve surrounds two cylindrical thermoplastic liners, an upstream liner and a downstream liner. The upstream liner contains a throughhole of a diameter equal to the diameter of the fluid handling system pipeline in which the valve should be installed. The downstream liner contains a throughhole of a diameter greater than the upstream liner. The downstream liner is further modified to contain a recessed cavity for permitting the flapper, mounted to the downstream liner, to rotate up and out of the flow stream to permit full-flow through the valve. The upstream and downstream liners are in contact with one another so that the throughholes of the liners define the central passage of the valve. The mating surfaces of the upstream and downstream liners are cut at an angle inclined to the center-line axis of the throughholes. The inclined mating surface of the upstream liner not in contact with the downstream liner defines an annular sealing surface around the throughhole of the upstream liner on which the flapper seals against back flow.
The flapper is also constructed from a thermoplastic material and has a circular domed-shaped sealing surface that seals against the upstream liner sealing surface. Molded into the flapper is a stainless steel screen which increases the weight and strength of the flapper. The flapper is pivoted on a thermoplastic pin or trunnion which is also impervious to the corrosive fluids. The inclined sealing surface of the upstream thermoplastic liner causes the flapper to contact the sealing surface at an angle other than vertical. Thus, the weight of the flapper, regardless of the orientation, initiates a seal and permits an effective seal against backflow at a lower internal pressure. A guidepin is provided in the upstream liner and an oppositely facing hole is provided in the downstream liner to guide the two thermoplastic liners into contact inside the metal sleeve.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:
FIG. 1 is a cross sectional view of the thermoplastic flapper check valve;
FIG. 2(a) and FIG. 2(b) is an end and a side view of the flapper, respectively; and
FIG. 3 is the flapper check valve as viewed from the downstream end with the flapper removed.
Similar referencee characters refer to similar parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1 which illustrates a cross sectional view of the thermoplastic flapper check valve, the valve 1 is shown composed of four major components, a cylindrical metal sleeve 14, an upstream thermoplastic liner 10, a downstream thermoplastic liner 20 and a flapper 16. Upstream liner 10 is shown contacting downstream liner 20 at interface 42 which is inclined at an angle A to the center-line axis of the central passageway of the valve 1. The angle A in the preferred embodiment of valve 1 is approximately 10 degrees but proper operation could be obtained if angle A is within the range of 5 to 20 degrees. While the valve works, at angles outside this range, the best performance is obtained when the angle is within the range. Upstream liner 10 contains a throughhole 38 whose diameter is equal to the diameter of the fluid handling system lines in which the valve 1 is to be used. Downstream liner 20 has a throughhole 40 of a diameter greater than the diameter of throughhole 38. The center-line axes of throughholes 38 and 40 are in alignment and define the central passageway through valve 1. The throughhole 40 of downstream liner 20 is further modified (see FIG. 3) to permit flapper 16 to rotate up and into a cavity 60 of liner 20 to permit the full-flow of the corrosive fluids through the valve 1. This recess cavity is illustrated in FIG. 3 in which the upper half of the internal surface 18 of throughhole 40 of the downstream liner has been removed to create cavity 60 defined by the surface 34 and 35.
FIG. 1 also illustrates the flapper 16 resting against an annular sealing surface 22 of the upstream liner 10 in which the domed shaped circular sealing ring 24 of flapper 16 (see FIG. 2(a)) acting against sealing surface 22 generates the seal to prevent back flow through the valve. Molded into the flapper 16 is a stainless steel wire screen 26 which provides added rigidity and strength to flapper 16 to enable it to seal against greater back pressures than would be possible without the screen. A metal screen is required rather than a solid plate because, in the molding process, the thermoplastic must flow through the metal screen to keep the metal from moving from the middle of the flapper 16. Although stainless steel is used for the screen, other wire screens would be possible because the screen is molded inside the thermoplastic and is protected from the corrosive fluids. Flapper 16 is also illustrated in FIG. 1, in dotted lines, in its full open position in the recessed cavity cut into downstream liner 20. Referring now to FIG. 2(a) and FIG. 2(b) which illustrates an end view and side view of flapper 16 respectively, a thermoplastic pin 32 is shown inserted through a radial extension 30 of generally disc shaped flapper 16. Pin 32 forms a trunnion for flapper 16 on which the flapper 16 is pivoted in downstream liner 20. A cut out 44 and slots 36 are provided in the mating end of downstream liner 20 opposite the flapper cavity 60 to provide clearance for the radial extension 30 and for receiving trunnion 32 of flapper 16 respectively. When trunnion 32 is in slot 36 flapper 16 is supported in the downstream liner 20 and rotates from the full open to the full closed positions about trunnion 32. Cut out 44 permits radial extension 30 to swing an arc as the flapper 16 moves from the full open to the full closed positions.
Referring now to FIG. 2(a) and FIG. 2(b), the sealing surface 24 of flapper 16 is shown as a generally dome-shaped raised circular ring molded on the side of the flapper 16 that rests against the sealing surface of the upstream liner 10. Referring now to FIG. 3, the internal surface 12 of the upstream liner 10 throughhole 38 is shown in relation to the internal surface 18 of the downstream liner 20 throughhole 40. The area of the upstream liner 10 mating end between the internal surface 12 of upstream liner 10 and internal surface 18 of the downstream liner 20 is the annular sealing surface 22 against which the sealing ring 24 of flapper 16 comes to rest when the flapper 16 is in the closed or check position. Again referring to FIG. 2(a) and FIG. 2(b), cut to the edge in the side of flapper 16 opposite the side containing the sealing ring 24 are bevels 33. The bevels 33 are cut to the outside edge of the back side of flapper 16 at a point below the radial extension 30 and on the edges displace 90° to either side of the extension 30. The slope of bevels 33 is approximately 10 degrees. The purpose of bevels 33 is to permit flapper 16 to rotate further into the cavity 60 (see FIG. 1 and FIG. 3) in the downstream liner 20 than would be possible without the bevels. The radius of the corners in the recess cavity 60 requires that the flapper 16 contain the bevels in order to allow the flapper to rotate completely out of the throughhole passage of valve 1 to permit full-flow through the valve.
Again referring to FIG. 1, a guidepin 28 is shown mounted in upstream liner 10. Contained in downstream liner 20 is an oppositely facing hole 29 for receiving the guidepin 28. Guidepin 28 functions to align and guide the downstream liner 20 into contact with upstream liner 10 when the two thermoplastic liners are assembled within sleeve 14. The guide pin 28 may be mounted into either of the liners with the oppositely facing hole contained in the other liner for accepting the pin during the assembly of the two liners. FIG. 1 also illustrates that when assembled, the thermoplastic liners at both ends of metal sleeve 14 extend slightly beyond the ends of the sleeve. The purpose for extending the thermoplastic liners beyond the length of the metal sleeve 14 is to allow for compression of the thermoplastic parts as the valve is installed into the fluid handling system pipelines. As the retaining flanges, between which is mounted the check valve 1, are drawn together, the thermoplastic is compressed to form a seal at the interface 42 between the upstream liner 10 and the downstream liner 20 and between the ends of the valve 1 and the pipeline flanges.
The internal diameter of metal sleeve 14, illustrated in FIG. 1, is slightly larger than the outside diameter of the thermoplastic liners 10 and 20 so that the liners may be easily inserted into the sleeve. Because the thermoplastic liners will be slightly expanded within the sleeve 14 when installed into the pipelines, any differences in the sleeve's internal diameter and the outer diameter of liners 10 and 20 will be taken up in the expansion of the liners as their ends are compressed towards each other. In this manner, there will be a tight fit between the liners 10 and 20 and the sleeve 14. Sleeve 14 functions to provide structural strength to the valve 1 to withstand the internal pressures from the corrosive fluids. Since the thermoplastic materials alone are not capable of withstanding high internal pressures, especially where there is a thin wall between the internal passageway and the exterior of the thermoplastic liners, the metal sleeve 14 is required to provide the structural strength to withstand those internal pressures. While a stainless steel metal sleeve 14 is shown in FIG. 1 and FIG. 3 and disclosed herein, other metals that will provide the required structural strength to the thermoplastic parts could be used. One such metal is Monel, an alloy of stainless steel and nickel. Other metals such as carbon steel, aluminum, etc. could be used. To prolong the life of valve 1, it is preferable that the metal sleeve 14 be impervious to the corrosive environments in which the valve will be used.
FIG. 1 illustrates a wafer type thermoplastic check valve but an alternate embodiment of a flange type thermoplastic check valve is possible. In order to obtain a flange type valve, upstream liner 10 and downstream liner 20 would have to be of a larger outer diameter to permit flange bolt throughholes to be drilled in both liners the entire length of the valve. Correspondingly, the metal sleeve 14 must be larger in diameter to allow for the increased diameters of the liners 10 and 20. The flange type valve requires that the flange bolts, that connect the valve into the pipeline, pass through the thermoplastic material, while the wafer type valve requires that the bolts pass on the outside and around the valve. For both types of valves, the thermoplastic liners are captured between the two flanges as the flange bolts are secured.
In normal operation, as flow is directed against the flapper from the upstream side, the flapper 16 moves off the seat 22 due to the rotation of flapper 16 on the trunnions 32. When fully open, flapper 16 is clear of the flow media; hence, only a low pressure drop is experienced across the valve. Normally about a 1 psi drop in pressure occurs through valve 1 at the normal flow rate. Table I shows the size of the fluid handling system pipelines and the flow rate (C v ) that represent a 1 psi pressure drop across the valve 1.
TABLE I______________________________________ C.sub.vSize Gallons Per Minute______________________________________1" 6011/2" 1152" 2753" 5254" 700______________________________________
When flow through valve 1 ceases, gravity causes flapper 16 to rotate down to the closed position in which the sealing surface 24 of the flapper 16 comes to rest on the sealing surface 22 of the upstream liner 10. This contact is achieved before flapper 16 assumes a vertical position because of the inclined angle of sealing surface 22. As back pressure developes in the downstream liner 20, flapper 16 is urged against sealing surface 22 and a seal is achieved between the upstream liner 10 and the flapper 16. Although the thermoplastic material used to construct the flapper 16 and thermoplastic liners 10 and 20 do not have memory, the generally dome shape of sealing surface 24 of flapper 16 may be flattened by repeated checkings over a period of time. However, this does not cause the flapper to loose its ability to seal because the sealing surface 22 is a flat surface and a squashing of the top of the dome in sealing surface 24 merely increases the area of sealing surface 24 that is in contact with sealing surface 22. Thus the life of the flapper check valve is significantly increased over that of the ball type check valves.
In assembling the valve of FIGS. 1-3, the trunnion 32 and radial extension 30 of flapper 16 are inserted into the slots 36 and cutout 44 of downstream liner 20. Upstream liner 10, having alignment pin 28 mounted therein, is inserted into the stainless steel sleeve 14. The downstream thermoplastic liner 20, containing the flapper 16, is then inserted into the opposite end of sleeve 14 and rotated until guide pin 28 and an oppositely facing alignment hole 29 in the liner 20 are in alignment. Liner 20 is then pressed into contact with liner 10. At this point, guide pin 28 has been inserted into alignment hole 29 and the inclined faces of liners 10 and 20 are in contact.
Depending upon whether the valve is of the wafer type or the flange type, the valve is installed into the fluid handling pipeline between the flanges provided for the valve. The flange bolts which capture the check valve in the pipeline are inserted and installed. As the flange bolts are tightened, the thermoplastic liners 10 and 20, extending slightly beyond the ends of sleeve 14, are squeezed together until the stainless steel liner 14 contacts the flanges. At this point, the valve is installed in the pipeline. As discussed above, the flapper type check valve may be installed in the fluid handling system in any orientation with no change in its performance characteristics. This is because the flapper responds to the pull of gravity, with the valve 1 in either a horizontal or vertical orientation, to rotate from the full open to the full closed positions when the through flow in the pipeline is zero.
Because of the simplicity in the design of the internal components of the check valve 1 disclosed herein, replacement or worn parts is a relative simple manner. The valve, whether of a waffer or flange design, is removed from between the flanges by removing the flange bolts. For a waffer model, not all of the flange bolts need be removed to remove the valve from between the flanges. Once the valve is removed from between the flanges, the worn internal parts may be easily removed from the stainless steel sleeve, a new piece inserted and the valve quickly replaced in the line. The present invention provides a streamline check valve because all of the valve parts are contained within the cylindrical metal outer sleeve 14. Thus, the need for a bonnet to cover the hinged rotation point of the flapper and a flapper recess cavity is not needed. However, the stainless steel metal sleeve 14 is needed because the thermoplastic material, from which the upstream lever 10 and downstream liner 20 are constructed, is not capable of withstanding large internal pressures. As discussed previously, by providing the metal sleeve 14, the valve is able to withstand the normal expected internal pressures in the corrosive fluid handling systems.
In describing the invention, reference has been made to a preferred embodiment. However, those skilled in the art and familiar with the disclosure of the invention may recognize additions, deletions, substitutions or other modifications which would fall within the preview of the invention as defined in the appended claims. | 4y
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CROSS REFERENCE TO RELATED APPLICATIONS
This is a divisional application of a co-pending application entitled "Vertically Foldable Window Covering and Retaining Clip", Ser. No. 470,874, filed Jan. 26, 1990, which is now U.S. Pat. No. 4,010,944, which is a continuation in part application of a copending application entitled "VERTICALLY ADJUSTABLE WINDOW COVERING AND CLIP", Ser. No. 231,870, filed Aug. 12, 1988, now U.S. Pat. No. 4,909,299, which is a continuation in part application of an application entitled "TEMPORARY WINDOW SHADES", filed on Apr. 13, 1987, assigned Ser. No. 037,686, now U.S. Pat. No. 4,836,265, all of which describe inventions by the present inventor.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to window coverings and, more particularly, to temporary selectively foldable window shades and clips therefor.
2. Description of the Prior Art
New home owners and renters very often find that they must wait a long time before they are able to install new shades or draperies across their windows. This is especially true in the case of custom made draperies, since the process of measuring, ordering and making the draperies is quite lengthy. Even ready made draperies are usually not purchased immediately as they are somewhat expensive and as the buyer usually shops around before finally selecting permanent draperies.
In order to protect one's privacy, as well as to block out bright sunlight, new occupants frequently resort to temporary measures, such as hanging sheets or pasting newspapers or the like over their windows. Such measures are usually unsatisfactory, as the sheets or newspapers are a nuisance to put up and tend to detract from the internal and external appearance of the house or apartment. In addition, there is no convenient way to raise and lower these types of window coverings. Accordingly, the occupant cannot readily vary the amount of light shining through the windows or selectively have a view of the outdoors.
The closest known attempt to solve the above problems is a temporary paper curtain which has a first strip of stiffener material attached to its top edge and a second strip of stiffener material attached to its bottom edge. The first strip serves as an attachment strip for attaching the curtain to a wall and the second strip serves as a weighting device to ensure that the curtain hangs correctly. In one embodiment of the device, bores are provided through each of the stiffener strips and a plurality of vertically spaced apart holes are provided along one side of the curtain. A pull cord passing through the bores and the aligned holes allow the curtain to be raised and lowered. This apparatus for raising and lowering the curtain is not entirely satisfactory, since the process of boring holes in the stiffener strips and threading the pull cord through the curtain adds to the cost and complexity of the product.
SUMMARY OF THE INVENTION
A sheet of rugged, relatively inexpensive material, such as nylon, polyester, or reinforced paper serves the function of covering a selected part of a window. The upper and lower edges of the covering are preferably folded to form hems and a stiffening rod is inserted into at least the lower hem to provide weight and urge the covering to hang flat. The hem along the top edge may be provided with double-sided adhesive tape, hook and loop type fasteners, or holes for receiving nails, hooks or the like, to secure the top edge to the upper window frame or a wall above the window. A pair of clips extend from the bottom stiffening rod. Each clip includes a support member supporting a planar flange extending in one direction and a hooked flange extending in the other direction. A plurality of slots and loops are formed in longitudinally spaced increments proximate each of the vertical edges of the covering. To raise the covering to a desired height, the covering is folded upwardly to positionally fix the bottom edge of the covering in the folded position by passing the hooked flange of each clip through a respective selected transversely aligned pair of slots in the covering. The folded part of the covering may be folded upwardly again and retained in place by penetrably engaging a transversely aligned pair of loops with the respective planar flanges. By easily disengaging the hooked flanges and planar flanges, the covering will unfold to its depending state and cover the underlying window.
A primary object of the present invention is to provide a vertically foldably adjustable temporary window covering for covering a selected part of a window.
Another object of the present invention is to provide an inexpensive window covering for covering a selectable portion of a window.
Yet another object of the present invention is to provide a clip for retaining at any of a plurality of locations a folded part of a window covering.
Still another object of the present invention is to provide a clip for selectively retaining multiple folds of a depending window covering.
A further object of the present invention is to provide an inexpensive clip attached to the lower edge of a window covering for positionally retaining one or more folds of the window covering to partially uncover the adjacent window.
A yet further object of the present invention is to provide a method for inexpensively covering a window to a selected extent.
A yet further object of the present invention is to provide a removably attached clip for retaining folded portions of a window covering to uncover a selected extent of an adjacent window.
These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be described with greater specificity and clarity with reference to the following drawings, in which:
FIG. 1 is an isometric view of a depending window covering locatable adjacent a window;
FIG. 2 is a partial view of the window covering and showing slots and loops of the window covering;
FIG. 3 is a partial view taken along lines 3--3, as shown in FIG. 2;
FIG. 4 is an isometric view of a clip usable with the window covering to retain it folded in place;
FIG. 5 is an isometric view showing the window covering in a single folded state;
FIG. 6 is an isometric view showing the window covering in a double folded state; and
FIG. 7 is a cross sectional view taken along lines 7--7, as shown in FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, there is shown, in representative form, a window 10 mounted within a frame 12 in wall 14. The window may be any type of window, such as a permanently closed window, a sliding glass window, a casement window, etc. Similarly, frame 12 may be made of any material, such as wood, metal, plastic, etc. Wall 14 may be of conventional construction, stone, stucco, etc.
Coverings for windows are used predominantly to limit the light passing through the window and for reasons of privacy. In conjunction therewith, the type or nature of the window covering is selected primarily for decorative purposes, barring some other overriding concern. At the time of initial occupancy of a dwelling, the windows are usually uncovered pending a decision by the occupant as to type, nature and design of the window coverings. Until permanent window coverings are obtained and installed, the need exists, for reasons stated above, to cover the windows. Preferably, any window covering used for temporary purposes should be capable of being selectively positionable for control of light transmitted through the window and to provide the capability for looking out through the window.
Window covering 20 may be opaque, translucent or may even be of a visually transparent but ultraviolet opaque material. Preferably, it is somewhat tear resistent and readily foldable. Whether window covering 20 is of man-made composite materials, natural fibers or a blend is unimportant for purposes of the invention. For artistic and decorative purposes, the window covering may be colored, patterned or textured.
Structurally, window covering 20 includes an upper edge 22 commensurate in configuration with the upper part of window 10, frame 12 or adjacent wall surface 14. The upper edge may be attached either to the window, to the frame or to the wall surface by two or more patches (24, 26) of double-sided adhesive tape. Other attachment means, such as nails, thumbtacks, hooks, etc. may also be used, if feasible and prudent. Upper edge 22 may include a hem 28, as illustrated, to provide additional rigidity. For long span installations or window coverings which may be exceedingly limp, stiffening means may be added to upper edge 22 to prevent droop of the upper edge or a plurality of attachment points may be used.
The planform of window covering 20 may be rectangular, as illustrated, or of other shape commensurate with the size and configuration of window 10. Alternatively, it may be oversized in situations where minimized light transmissibility is of major concern or where decorative considerations so suggest.
Lower edge 30 of window covering 20 may be hemmed with hem 32, as illustrated, to add stiffness or rigidity to the lower edge. A bar or rod 34 may be inserted within the hem to further stiffen the lower edge. The rod will also add weight, which weight will encourage the window covering to hang straight.
As shown in FIGS. 1, 2 and 3, a plurality of vertically aligned penetrable means, such as slots 40, are disposed proximate side edge 42 of window covering 20. A plurality of similar slots 44 are vertically aligned along side edge 46. It is intended that slots 40 be transversely generally aligned with slots 44. A plurality of loops 50 extend from rear surface 52 of window covering 20, which loops are in general vertical alignment with slots 40 along edge 42. These loops may be a strand of thread or plastic filament. The latter is particularly useful in that plastic filaments may be obtained which include integrally formed cross members 54,56 at each end. To install loops 50, cross member 54, after being bent into general alignment with the adjacent part of the filament, is penetrably inserted through aperture 58 in window covering 20. Similarly, cross member 56 is bent into general alignment with the adjacent part of the filament and inserted through aperture 60. The cross members, after self alignment transverse to the axis of the filament, will preclude withdrawal of the filament through apertures 58,60. A plurality of similar loops 62 are vertically aligned along edge 46 of window covering 20 and in general vertical alignment with slots 44. As particularly illustrated in FIGS. 2 and 3, the cross members of loops 50 and 62 are disposed adjacent front surface 64 of the window covering and the loop itself is disposed adjacent rear surface 52.
Referring jointly to FIGS. 1 and 4, clip 70 and its function will be discussed in detail. The clip includes retention means 72 for engaging lower edge 30. In the embodiment illustrated, the retention means is a segment of a split cylindrical sleeve having opposed longitudinal edges 74,76. The diameter of the retention means or sleeve 72 is a function of the diameter of rod 34 and the material of hem 32 extending thereabout, as illustrated in FIG. 1. Preferably, the sleeve is of resilient material to permit the sleeve to grippingly engage the partially encircled rod. Suspension means 78 for selective engagement with the slots and loops includes a support member 80 extending laterally from and in longitudinal alignment with sleeve 72. The support member supports a flange member 82 in a non perpendicular relationship therewith. The flange member includes a planar flange 82 set at an obtuse angle with respect to support member 80 and a hooked flange 86 set at an acute angle with regard to the support member. It may be noted that the planar flange and a substantial part of the hooked flange lie in a common plane and are an extension of one another. The length of each of slots 40,44 is commensurate with the width of flange member 82. Moreover, the width of each of the slots is sufficient to accommodate penetrable engagement by hooked flange 86. Similarly, the length of each of loops 50,62, exposed on side 64 of window covering 20, is commensurate with the width of planar flange 84. Necessarily, these loops must have sufficient slack to permit engagement with planar flange 84 of the respective clips without causing the adjacent portion of the window covering to buckle or have a hump.
Referring jointly to FIGS. 5, 6 and 7, the operation of the present invention will be described in detail. Window covering 20 depends from the upper part of the frame surrounding window 10, as illustrated in FIG. 1. Being of a length and width greater than the window, the window covering will cover the window. Rod 34, providing both weight and rigidity to bottom edge 30 of the window covering will tend to maintain the window covering generally flat and planar with the window. The additional weight provided by clips 70 may be of assistance in retaining the window covering in place.
To uncover a portion of window 10 for the purpose of letting in light or to see through the window, a lower part of the window covering is folded upwardly upon itself, as represented b first fold portion 100 illustrated in FIG. 5. The first fold portion is retained in place by penetrably engaging hooked flange 86 of flange member 82 with slot 40. A second clip 70 is in similar engagement with transversely aligned slot 44. Because of the angled relationship of hooked flange 86 with respect to support member 80 and the depending relationship of first fold portion 100, the weight of the first fold portion, including rod 34, will tend to urge penetration and maintain hooked engagement between clip 70 and window covering 20. With such urging, possible flapping of the window covering due to an airflow through an opened part of window 10 will generally not result in disengagement of first fold portion 100. Moreover, accidental brushing against the first fold portion will tend not to result in disengagement of clips 70 from the engaged slots.
To obtain yet further exposure of window 10, first fold portion 100 may be folded upon itself, as depicted by second fold portion 102, as shown in FIGS. 6 and 7. In this configuration, planar flanges 84 of the respective clips 70 are engaged by loops 50,62. Because of the angular orientation of the planar flanges, the weight of second fold portion 102 will tend to encourage and maintain penetrable engagement between the loops and the respective planar flanges.
To cover a portion of window 10, second fold portion 102 may be slightly lifted by drawing it upwardly and away from the respective clips 70 to bring about disengagement of loops 50,62 with the corresponding planar flanges of clips 70. Thereafter, second fold portion 102 may be released to permit it to drop. Similarly, first fold portion 100 is readily released by repositioning lower edge 30 upwardly and away from window 10 to disengage hooked flanges 86 of clips 70 with corresponding slots 40, 44. The lower edge may then be allowed to drop whereafter covering 20 will assume the position depicted in FIG. 1 to cover window 10.
A plurality of vertically spaced slots 40 and 44 in covering 20 permit altering the height of first fold portion 100 from a minimal height to approximately half of the height of window covering 20. A plurality of vertically spaced loops 50 and 62 are incorporated in window covering 20 to permit variations in height of second fold portion 102. Accordingly, the initial exposure of window 10 by first fold portion 100 may be incrementally increased by second fold portion 102 and depending upon which ones of transversely aligned loops 50,62 are brought into engagement with respective clips 70. With the configuration of loops illustrated in the figures, approximately 3/4 of window 10 can be uncovered upon a maximum height of each of the first fold portion and the second fold portion.
Because the cross section of clip 70 is uniform throughout the longitudinal length of the clip, it is well adapted for manufacture by conventional extrusion techniques. Accordingly, an extended length of clip 70 can be readily manufactured of suitable plastic material at a very nominal cost. Thereafter, the length can be cut to any length segments suitable for the purposes described above. By forming clip 70 of material having a certain degree of resiliency and flexibility, any given diameter of retention means 72 can accommodate a range of different diametrically sized rods 34 and encircling hem 32. It is to be noted that the retention means can be otherwise configured to accommodate various means for attaching clip 70 to lower edge 30, whether the lower edge is flat, rectangular, circular, etc. Moreover, other fastening means may be employed to secure retention means 72 to the lower edge of the covering.
From the above description and the accompanying illustrations, it will be apparent that window covering 20 is relatively simple in structure and yet clip 70 is sufficiently sophisticated in design and configuration to permit great ease in folding over and retaining one or more folds of the window covering. Even though window covering 20 may be of sufficiently inexpensive material to be used as a temporary discardable covering, it is capable of providing all of the advantages of more conventional window coverings with respect to light control, privacy, selected exposure of the window and decorative value.
While the principles of the invention have now been made clear in an illustrative embodiment, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, elements, materials, and components, used in the practice of the invention which are particularly adapted for specific environments and operating requirements without departing from those principles. | 4y
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BACKGROUND OF THE INVENTION
The present invention relates to a non-invasive method and apparatus for detecting biological activities in a fluid specimen, such as blood. The specimen and a culture medium are introduced into a sealable container and exposed to conditions enabling metabolic processes to take place in the presence of microorganisms.
Usually, the presence of microorganisms such as bacteria in a patient's body fluids, particularly blood, is determined using blood culture vials. A small quantity of blood is injected through the sealing rubber septum into a sterile vial containing a culture medium. The vial is incubated at 37° C. and monitored for bacterial growth.
Common visual inspection involves monitoring the turbidity of the liquid suspension. Known instrumental methods detect changes in the carbon dioxide content in the head space of the culture bottles, which is a metabolic by-product of the bacterial growth. Monitoring the carbon dioxide content can be accomplished by methods well established in the art, including radiochemical, infrared absorption at a carbon dioxide spectral line, or pressure/vacuum measurement. These methods, however, require invasive procedures which result in the well-known problem of cross-contamination. In case of vacuum/pressure measurement, on the other hand, any temperature change within the vial head space also generates a pressure change which is not related to biological activities. Therefore, an additional head space temperature measurement is required in order to distinguish between biological and temperature effects. Non-invasive head space temperature monitoring, however, represents an extremely difficult problem, and there are currently no practical solutions. Further, the metabolic activity of some microorganisms can result in very high head space pressures. This means that while a pressure sensor has to be sensitive in order to allow detection of diverse microorganism species, it must also be protected from extreme pressure. Depending on the technology used, these two requirements often contradict each other and cannot be simultaneously satisfied.
Recently, novel non-invasive methods have been developed which use chemical sensors inside a vial. Such sensors often respond to changes in the carbon dioxide concentration by changing their color or by changing their fluorescence intensity. The outputs from these sensors are based upon light intensity measurements. This means that errors may occur, particularly if the light sources used to excite the sensors, or the photodetectors used to monitor intensities, exhibit aging effects over time.
The disadvantages of intensity-based methods can be overcome by utilizing modulated excitation light in combination with fluorescent sensors that change their decay time in response to changing carbon dioxide concentration. Using this method, intensity measurements are replaced with time measurements, so intensity changes do not influence the results. Current fluorescent decay time sensors, however, require high brightness short-wavelength light sources (550 nm or shorter) that are intensity-modulated at very high frequencies (typically above 100 MHz). A preferred embodiment would be a 5-mW green helium neon (HeNe) laser (543.5 nm), externally modulated by means of an acousto-optic light modulator. The laser/modulator combination is expensive, and it is expected that in practice the vials would have to be moved to the laser instead of having a light source for each vial. Further, such instruments would have moving parts and the time interval between successive measurements for each vial would be relatively long. And, it is not likely that inexpensive high-brightness short-wavelength semiconductor diode lasers will be developed in the near future.
SUMMARY OF THE INVENTION
The present invention overcomes problems identified in the prior art by providing a method and apparatus for detecting biological activities in blood culture bottles that is non-invasive, does not require chemical sensors or high-brightness short-wavelength light sources, is safe from extreme pressure, is head-space-temperature compensated, and is relatively inexpensive, such that each vial can be monitored continuously, meaning that diagnostic instruments may be constructed with non-moving vials.
According to the present invention, a culture medium and blood specimen are introduced into a sealable glass vial. The normally incompressible fluid suspension is made compressible, and the fluid level movement that results from microorganism growth related pressure changes within the vial head space may thus be measured.
A preferred method for making the fluid suspension compressible according to the present invention is to introduce a gas bag into the medium/blood mixture and submerge it below the upper level of the fluid, beneath the fluid-gas interface. It is also possible to introduce a plurality of small gas bags or compressible particles into the fluid, and then secure them. The contents of the gas bag may be atmospheric air, a mixture of gases, or other compressible fluids. As explained below, the pressure effect of head space temperature changes can be significantly reduced by using a gas bag filled with a gas having a density equal to that in the head space. In such a situation, an identical temperature change occurring within the head space and within the gas bag will result in identical pressure changes. Consequently, the fluid level will not be altered by a temperature change so that additional head space temperature monitoring is not required.
In order to monitor the fluid level inside the blood culture vial, an instrument according to the present invention has a light source arranged on one side of the vial, and a large-area photodetector on the other side of the vial. The light source and the photodetector are arranged so that if the fluid level changes, the percentage of the photodetector area receiving light from the lamp will also be affected, resulting in an altered photodetector output current. Thus, the head space pressure inside the blood culture vial can be monitored by recording the photodetector output signal.
In practice, the fluid-gas interface at an inner glass wall is shadow-imaged onto a large-area photodetector. It would be understood by someone skilled in the art that a lens system can also be used to realize the same imaging principle. An instrument according to the invention may include a color filter in the light path between the light source and the photodetector in order to increase the edge effect of the fluid-gas interface.
Gas bubbles are known to exist at the fluid-gas interface, particularly when the vials are shaken. Some forms of microorganisms also generate such gas bubbles. In order to circumvent problems connected with such bubbles, an instrument according to the invention may also include a sharp-edged opaque annular float disposed within the vial. When such a float is used, it is the upper float edge at an inner glass wall which is imaged onto the photodetector.
The pressure sensitivity of an instrument according to the present invention can be increased using an optical magnification effect. The distance between the light source and fluid or float edge can be made many times smaller than the distance between this edge and the photodetector.
A preferred light source would include a plurality of spaced horizontally oriented filaments. Such a light source allows the level monitoring system to be operated with varying amounts of blood inoculated into the vial.
An alternative embodiment of the present invention comprises a vial that is basically a glass tube with two flanges. A lower flange is sealed with a septum which has a gas bag secured to it. The gas bag can be attached to the septum before sealing the vial. The upper flange is used in the same manner as with ordinary vials, i.e., inoculation of the medium with blood.
In order to make the optical level monitoring system more accurate, the large-area analog photodetector can be split into two vertical segments. Both segments are covered with transmission masks containing grating-like horizontal elements. The grating-like elements of each segment are displaced relative to the elements of the other segment. Additionally, the two masks have a slightly different overall transmission. The two photodetector outputs are connected with the inputs of a differential amplifier. If the fluid level moves, the output signal of the amplifier shows oscillations in accordance with the mask grating constants, resulting in a trend over time concerning the output signal DC component. This trend establishes whether the fluid level is rising or falling, i.e., if the pressure is decreasing or increasing. In this way, the linearity of the level monitoring system is determined by the masks and can be made very high. It is also possible to use a linear photodetector array instead of the large area analog photodetector.
Besides a filament lamp, other acceptable light sources are those which have an extremely narrow emitting active area. These include light emitting diode chips and diode lasers. These latter light sources result in a very sharp edge imaging and, consequently, a high resolution.
According to another embodiment of the present invention, a culture medium and a blood specimen are introduced into a sealable glass vial. The vial is pivotally mounted. The normally incompressible fluid suspension is made compressible. Generally, at least one incompletely inflated gas bag is submerged below the upper level of the fluid on one side of the pivot point of the vial. Biological activities within the blood culture medium, such as bacterial growth processes, will result in a pressure change in the vial head space. This pressure change is transmitted through the fluid towards the gas within the gas bag which changes its volume. Due to the volume change of the gas bag gas, fluid moves from one side of the vial to the other, and the torque of the vial changes. Therefore, biological activities such as bacterial growth can be detected by monitoring the vial torque, e.g., through the use of a simple force sensor.
BRIEF DESCRIPTION OF THE DRAWINGS
The various features, objects, benefits, and advantages of the present invention will become more apparent upon reading the following detailed description of the preferred embodiments, along with the appended claims in conjunction with the drawings, wherein reference numerals identify corresponding components, and:
FIG. 1 shows an embodiment of the present invention in which the fluid-gas interface near the photodetector is imaged.
FIG. 2 illustrates an embodiment which takes advantage of optical magnification by imaging the fluid-gas interface near the lamp onto the photodetector.
FIG. 3 shows an embodiment similar to that in FIG. 2, but with a multi-filament light source.
FIG. 4 illustrates an embodiment using an extended gas bag in order to increase the pressure sensitivity, and an opaque float in order to avoid degradation of the pressure resolution by gas bubbles at the fluid-gas interface.
FIG. 5 illustrates an embodiment based on a vial with two flanges with the gas bag secured to the lower flange.
FIG. 6 shows a detector arrangement comprising two large-area photodetectors covered having grating-like transmission masks, and coupled to a differential amplifier.
FIG. 7 is a calculated plot showing an oscillating output signal and the fluid level-dependent DC component obtainable using the detector arrangement illustrated in FIG. 6.
FIG. 8 shows a plot of the output signal obtained using the embodiment of FIG. 2 for periodic pressure changes of 8 cm H 2 O column.
FIG. 9 illustrates the response to strong external mechanical shocks against the vial of a system according to the embodiment of FIG. 2.
FIG. 10 shows the output signal of an instrument according to FIG. 2 for pressure steps of 1 cm H 2 O column within the range -5 cm to +26 cm relative to room pressure.
FIG. 11 shows an instrument for detecting biologically active agents according to the present invention, with an embodiment containing a force sensor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
One embodiment of a detection instrument 20 embodying the principles and concepts of the present invention is depicted schematically in FIG. 1. The disclosed instrument comprises a glass vial 22 with two side walls 24 and 26, a bottom 28, and an opening 30 which is sealed with a septum 32. Vial 22 contains a combined medium/blood mixture 34 with a head space 36. The normally incompressible fluid is made compressible through the use of a gas bag 38 which is positioned below the upper level 40 of mixture 34, i.e., below the fluid-gas interface. While a gas bag is shown, it is also possible to introduce a plurality of small gas bags or compressible particles into the mixture, and then secure them, e.g., by means of a plastic mesh. In order to monitor the fluid level inside vial 22, a single filament light source 42 is arranged in close proximity to wall 24 and a large-area photodetector 44 is in close proximity to wall 26. Photodetector 44 may be a photodiode. Light source 42 and photodetector 44 are arranged so that an edge 46 of the fluid, the fluid-gas interface at the inner periphery 48 of wall 26, is shadow-imaged onto photodetector 44. If level of mixture 34 changes, the percentage of the photodetector area receiving light from the light source will also be affected, resulting in an altered photocurrent output signal. Thus, the pressure inside vial 22 can be monitored by recording the photodetector output signal. Other approaches, including a lens system, may be used as well.
Detection instrument 20 also includes a color filter 50 disposed between light source 42 and photodetector 44. It is used to increase the edge effect of the fluid-gas interface. Light source 42, photodetector 44, and filter 50 comprise the level monitoring system of detection instrument 20. It is well known that blood shows less absorption in the red spectral region than in the green/blue region. Therefore, filter 50 is a short-pass filter with a cutting wavelength of about 600 nm or shorter.
The function of gas bag 38 is explained in conjunction with the well-known equation:
pV=mRT (1)
In (1), the gas bag volume, V, the gas bag gas pressure, p, and the gas bag gas temperature, T, are interdependent parameters. The mass of gas enclosed in the gas bag is depicted by m while R is the universal gas constant. A bacterial growth-related pressure change within head space 36 will be transmitted toward gas bag 38, resulting in a volume change, dV, of the gas bag. For a constant temperature, the following pressure-related volume change may be derived from equation (1): ##EQU1## If it is assumed that the gas bag has a cross-sectional area, A, identical to the inner vial cross-sectional area, and a height, h, a change of the gas bag volume V=Ah results in a change of the upper fluid level, dh, given by the following equation: ##EQU2##
In FIG. 1, air bag 38 does in fact have a cross-sectional area, A, identical to the inner cross-sectional area, A, of vial 22. Equation (3) shows that the pressure-related fluid level change, dh, is independent of the vial cross-sectional area, but is proportional to the gas bag height. Bacteria are supposed to create a pressure increase of typically +20 cm H 2 O column. Therefore, a fluid level decrease of 0.6 mm is expected for a gas bag of 3 cm height, assuming a pressure p=1,000 cm H 2 O for the gas bag which is approximately equal to the atmospheric pressure.
Gas bag 38 does not have to be made out of elastic material. It is not the gas bag material, but the gas enclosed within it, which acts as an almost ideal "volume spring". This fact allows for an excellent long-time stability of the pressure sensor arrangement according to the present invention. Bacteria can also produce a temporary pressure decrease, however, resulting in an expansion of the gases within gas bag 38. As a result, gas bag 38 should be incompletely filled with gas in order to allow for possible gas volume expansions.
FIG. 2 illustrates an arrangement that takes advantage of an optical magnification effect. Detection instrument 60 is very similar to instrument 20. It comprises a glass vial 22 with two side walls 24 and 26, a bottom 28, and an opening 30 which is sealed with a septum 32. Vial 22 contains a combined medium/blood mixture 34 with a head space 36. Gas bag 38 is positioned below the upper level 40 of mixture 34. The level detection system comprising light source 42, photodetector 44 and filter 50 may also be the same. The positioning of the light source, photodetector, and filter is different, however. If the distance between light source 42 and the left fluid edge 62 is ten times smaller than the distance from this edge to photodetector 44, than the optical magnification is ×10. This means, a gas bag of 3 cm height creates a 6-mm displacement of the dark/bright transition at the photodetector for a pressure change of 20 cm H 2 O column.
FIG. 3 shows an arrangement 70 which is very similar to the one in FIG. 2. It comprises a glass vial 22 with two side walls 24 and 26, a bottom 28, and an opening 30 which is sealed with a septum 32. Vial 22 contains a combined medium/blood mixture 34 with a head space 36. Gas bag 38 is positioned below the upper level 40 of mixture 34. Photodetector 44 and filter 50 may also be the same. The single filament light source 42, however, is replaced with a multi-filament light source 72 in order to adapt the system to varying blood volumes. Light source 72 has horizontally oriented filaments 74 arranged parallel to each other and displaced approximately 1 to 2 mm apart. Light source 72 allows the level monitoring system to be operated for varying amounts of blood inoculated into vial 22. In operation, an instrument control device 76 such as a computer activates the vertical most filament 74 first. This may result in maximum photocurrent output if mixture 34 does not block part of the light. In a next step, control device 76 will turn off the first filament and turn on the next filament down. This procedure is repeated until the photocurrent output signal of photodetector 44 reaches a level equal to approximately 50% of the maximum photocurrent, which is the optimum operating condition for the level monitoring system. For the next reading, control device 76 will start with the previously optimum filament. For a typical vial, such as a BACTEC® brand vial, 5 ml of blood is recommended. If a possible range of 3 ml to 7 ml is assumed, the fluid level in vials with an inner diameter of 39 mm could vary by 3.4 mm. This means that only a few filaments 74 would be required. Line filament lamps can emit an intense light. The absorption of glass vial 22 in the green/blue spectral range is rather low. Therefore, relatively inexpensive photodetectors such as pn photodiodes can be used in order to attain a sufficient signal-to-noise ratio.
Besides a filament lamp, other suitable light sources are those which have an extremely narrow emitting active area. These include light emitting diode chips and diode lasers. These latter light sources result in very sharp edge imaging and, consequently, high resolution.
A different embodiment of the present invention, a detection device 90, is shown in FIG. 4. It comprises a glass vial 92 with two side walls 94 and 96, a bottom 98, and an opening 100 which is sealed with a septum 102. Vial 92 contains a combined medium/blood mixture 104 with a head space 106. Gas bag 108 is positioned below the upper level 110 of mixture 104. A multi-filament light source 72 and photodetector 44 are also shown.
Vial 92 has an extended height. As a result, gas bag 108 is larger, resulting in improved pressure change resolution. Assuming a gas bag height of 6 cm, a 12 mm displacement of the dark/bright transition at the photodetector for a pressure change of 20 cm H 2 O column is obtained. In other words, vials with an extended height offer a chance to reduce the time necessary to detect bacterial growth.
Gas bubbles are known to exist at the fluid-gas interface, particularly when a vial is shaken. Some forms of microorganisms also generate such gas bubbles. In order to circumvent problems connected with such bubbles, detection instrument 90 includes a sharp-edged annular float 112 disposed above upper level 110 of mixture 104. When such a float is used, it is the float edge 114 which is imaged onto photodetector 44. When utilizing a float, no short-pass color filter is necessary. Instead, filter 116 is a narrow-band filter that transmits the light coming from light source 72. Such a filter is advantageous in order to prevent unwanted background radiation from reaching photodetector 44. A narrow-band filter is extremely effective if light source 72 comprises narrow-band light emitting diode chips or diode lasers.
Another embodiment of the present invention is illustrated by the detection instrument 130 of FIG. 5. This arrangement comprises a vial 132 with a medium/blood mixture 133 that is basically a glass tube 134 with two flanges 136 and 138. Lower flange 136 is sealed with a septum 140 which carries a gas bag 142. Gas bag 142 can be attached to septum 140 before sealing vial 132. Septum 144 seals upper flange 138 to create head space 146. This embodiment of the invention is advantageous with respect to ease of blood vial assembly during mass production. The level detection system 148 is identical to that of FIG. 4, as is the use of float 112.
As stated above, any temperature change occurring within the vial head space also generates a pressure change. Obviously, this pressure change is not related to bacterial growth. Therefore, an additional head space temperature measurement would be required in order to distinguish between bacterial growth effects and temperature effects. Non-invasive head space temperature monitoring represents, however, an extremely difficult problem, and has yet to be solved in a practical manner.
In an instrument according to the present invention, however, no head space temperature monitoring is in fact required. Equation (1) can be transformed as follows: ##EQU3## In (4), ρ is the gas density within the head space. For the temperature-related pressure change, the following may be calculated from equation (4): ##EQU4##
Equation (5) shows that the temperature-related pressure change, dp, does not depend on p or V, but depends only on the gas density. This means that the same temperature-related pressure change is realized for the head space and for the gas bag if the gas densities are equal. Therefore, the upper fluid level in the blood culture vial will not change due to overall temperature changes within the instrument, and no temperature monitoring is required.
In order for this assumption to be most accurate, the gas bag should be in facial contact with the inner periphery of the vial side walls. This way temperature changes affecting the head space will affect the gases within the gas bag to the same extent. Inaccurate results are possible if some of the medium/blood mixture is disposed between the gas bag and the side walls of the vial since the instantaneous temperature may not be the same. In practice, the density of atmospheric air within the gas bag has generally been sufficiently close to the density of gases in the head space so as not to require a special gas mixture for the gas bag. Such a special mixture may be easily prepared, however, and used within the gas bag.
FIG. 6 shows a photodetector arrangement 160 which may be used in order to make the optical level monitoring system more accurate. Large-area photodetector 162 is split in two vertical segments 164 and 166. Segments 164 and 166 are covered with transmission masks 168 and 170 containing a plurality of uniformly-spaced grating-like horizontal elements 172 and 174. Gratings 172 and 174 are displaced relative to each other by one-half of the grating constant, where the grating constant equals the distance between two adjacent horizontal grating elements. Additionally, masks 168 and 170 have a slightly different overall transmission. The two photodetector outputs 176 and 178 are connected with inputs of a differential amplifier 180 which has an output signal 182. A voltage bias 184 is applied to the photodetector inputs 186 and 188.
If level 190 of medium 192 moves, output signal 182 shows oscillations in accordance with the mask grating constant. Monitoring the output signal oscillations allows for a high pressure resolution. In this way, the linearity of the level monitoring system is determined by masks 168 and 170 and can be made very high. In addition to the oscillating behavior, the output signal shows a trend concerning the output signal DC component. This trend indicates if level 190 is rising or falling, i.e., if the pressure is decreasing or increasing.
The optical transmission of the two grating-like masks 168 and 170 can be approximated by the following equation:
T.sub.1 (h)=A[1+R sin(kh-θ] (6)
and
T.sub.2 (h)=B[1+S sin(kh)] (7)
where A and B represent the average transmission, R and S represent the mask transmission modulation, k stands for 2π/M with M as the grating constant, and h is the fluid level. The mask's relative displacement is characterized by θ, which is set to π. θ represents the phase shift between the sensors. By positioning the horizontal grating elements 172 and 174 as discussed above, the phase shift between them is π radians or 180°. Thus, the difference between the two photocurrents of each of masks 168 and 170 is maximized for very small fluid level changes.
The fluid level-dependent photocurrent, I(h), is given by the following equation: ##EQU5## where J o characterizes the system configuration including the light source optical output power, geometry factors, optical filters, and the photodetector responsivity. The subscript n can be either 1 or 2, referring to the two detector segments. The photocurrent difference, ΔI, measured by the differential amplifier is given by the following equation: ##EQU6##
FIG. 7 shows the calculated photocurrent difference of equation (9) for specific transmission and modulation values. In the plot shown, the average optical transmission A of mask 168 is 0.500, and mask 170 has an average transmission B of 0.485. Therefore, the masks differ in their transmission by 3%. The transmission modulation R and S for both masks is assumed to be 0.900. The grating constant M is 0.2 mm. FIG. 7 indicates that by introducing masks 168 and 170, fluid level changes less than 0.2 mm can be detected easily. By using computer analysis procedures, high resolutions good linearity and a high dynamic range can be established. The sinusoidal waves create an envelope. From their peaks it is possible to determine how much the fluid level has changed. At the same time, by measuring the average ΔI, the average pressure can be calculated. The average pressure may give information about the type of bacteria. The masks can be mass-produced with the required accuracy and at low cost, using known photographic technologies. It is also possible to use a linear photodetector array instead of a large area analog photodetector.
FIG. 8 shows a plot of the photodetector output signal with respect to time obtained from a detection instrument 60 according to FIG. 2. Periodic pressure changes of 8 cm H 2 O column were introduced.
FIG. 9 illustrates the response from a detection instrument 60 according to FIG. 2 in terms of a change in pressure change with respect to time. Strong, but brief external mechanical shocks have been imposed upon vial 22.
FIG. 10 shows the output signal from a detection instrument 60 according to FIG. 2. Pressure steps of 1 cm H 2 O column have been introduced within the range of -5 cm to +26 cm relative to atmospheric pressure.
A detection instrument 200 embodying the principles and concepts of the present invention via a different measurement approach is depicted schematically in FIG. 11. The instrument comprises a glass vial 202 sealed with a rubber septum 204 and containing a frame 206 which holds an incompletely inflated gas bag 208. Vial 202 holds a medium/blood mixture 210 which penetrates frame 206 so that gas bag 208 is completely surrounded by fluid. The vial head space 212 extends all the way from the rubber septum 204 to the bottom 214 of vial 202.
Vial 202 is mounted within a sleeve 216 and is kept in position by a plate spring 218. Sleeve 216 is linked to a bearing support 220 via a rocker bearing 222, and the bearing support 220 is mounted onto a base plate 224. The feeler 226 of a force sensor 230 passes though an aperture 228 in base plate 224 and is used to monitor the vial torque.
As shown above in equation (2), the pressure-related volume change, dV, is proportional to the gas bag volume, V. Bacteria are supposed to create a pressure increase of typically +20 cm H 2 O column. Therefore, a volume change of 0.72 ml for a gas bag of 36 ml volume is expected, assuming a pressure p=1000 cm H 2 O for the gas bag gas, which is approximately equal to the atmospheric pressure. An amount of fluid with a volume dV/2 is moving from one side of vial 202 to the other side to generate a vial torque change. Thus, the fluid level is at least indirectly changed as well.
In order to estimate the expected bacterial growth related torque change, a rod shaped gas bag of length, L, and cross-sectional area, A, extending from the rocker bearing 222 to the bottom 214 of vial 202 are assumed. In addition, it is assumed that the gas bag volume change, dV, results in a constant cross-section change, dA, independent of the distance, l, from rocker bearing 222. Based on these assumptions, the vial torque change, dM, is calculated as follows: ##EQU7## where ρ is the density of the fluid, and g is the force of gravity, 9.81 m/s 2 . In equation (10), the factor 1/2 in front of the integral results from the fact that only half of the moving fluid crosses the rocker bearing.
The force change, dF, measured by force sensor 230 at a distance, l, from rocker bearing 222 is given by the following equation: ##EQU8## Equation (11) shows, that for L/l=4 the expected force change, dF, is equal to the weight of a fluid with volume dV=0.720 ml. Equation (11) also shows that dF is dependent on L/l, but independent of the absolute value of L. Therefore, an instrument according to the present invention would not necessarily require vials of extended length.
This embodiment also results in the same temperature-related pressure change for the head space 212 and gas bag 208 when the gas densities of each are equal. When the gas densities are the same, no fluid will move across rocker bearing 222 due to overall temperature changes in detector device 200, and no temperature monitoring is required.
A further embodiment of this invention would eliminate the need for a device to measure the torque. Vial 202 may be adjusted with respect to bearing 222 so that an exact equilibrium state is reached. Starting from this equilibrium state, a very fine detuning is accomplished in such a way that the side of the vial not containing the gas bag is lowered until it comes into contact with a base plate. Base plate 224 may be set up so that only a relatively small tilting angle is reached. In this state, a bacterial growth related pressure increase will result in the movement of fluid towards the uplifted vial side. As soon as this side becomes heavier than the originally tipped side, it will tip down instead.
Thus, it is possible to construct an instrument according to the present invention which may be used entirely without electricity.
Thus, while the preferred embodiments of the present invention have been described so as to enable one skilled in the art to practice the apparatus and method of the present invention, it is to be understood that variations and modifications may be employed without departing from the purview and intent of the present invention, as defined in the following claims. Accordingly, the proceeding description is intended to be exemplary and should not be used to limit the scope of the invention. The scope and the invention should be determined only by reference to the following claims. | 4y
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CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of application Ser. No. 09/842,274 filed Apr. 24, 2001, which in turn is a continuation-in-part of application Ser. No. 09/574,538, filed May 18, 2000, now U.S. Pat. No. 6,331,354, which is a continuation-in-part of application Ser. No. 09/256,197, filed Feb. 24, 1999, now U.S. Pat. No. 6,210,801. All the above applications are herein fully incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention is directed to pulps useful for making lyocell-molded bodies, including films, fibers, and non-woven webs, and to methods of making such pulps useful for making the lyocell-molded bodies, to the lyocell-molded bodies made from the pulps and to the methods for making the lyocell-molded bodies. In particular, the present invention is directed to using “young” wood (often characterized as “core wood”, “juvenile wood”, “low specific gravity wood” or, in some cases as “thinnings”.).
BACKGROUND OF THE INVENTION
[0003] Cellulose is a polymer of D-glucose and is a structural component of plant cell walls. These cells are referred to as fibers. Cellulosic fibers are especially abundant in tree trunks from which they are extracted, converted into pulp, and thereafter utilized to manufacture a variety of products.
[0004] Rayon is the name given to a fibrous form of regenerated cellulose that is extensively used in the textile industry to manufacture articles of clothing. For over a century, strong fibers of rayon have been produced by the viscose and cuprammonium processes. The latter process was first patented in 1890 and the viscose process two years later. In the viscose process cellulose is first steeped in a mercerizing strength caustic soda solution to form an alkali cellulose. The cellulose is then reacted with carbon disulfide to form cellulose xanthate, which is then dissolved in dilute caustic soda solution. After filtration and deaeration, the xanthate solution is extruded from submerged spinnerets into a regenerating bath of sulfuric acid, sodium sulfate, and zinc sulfate to form continuous filaments. The resulting viscose rayon is presently used in textiles and was formerly widely used for reinforcing rubber articles such as tires and drive belts.
[0005] Cellulose is also soluble in a solution of ammonia copper oxide. This property forms the basis for production of cuprammonium rayon. The cellulose solution is forced through submerged spinnerets into a solution of 5% caustic soda or dilute sulfuric acid to form the fibers, which are then decoppered and washed. Cuprammonium rayon is available in fibers of very low deniers and is used almost exclusively in textiles.
[0006] The foregoing processes for preparing rayon both require that the cellulose be chemically derivatized or complexed in order to render it soluble and therefore capable of being spun into fibers. In the viscose process, the cellulose is derivatized, while in the cuprammonium rayon process, the cellulose is complexed. In either process, the derivatized or complexed cellulose must be regenerated and the reagents used to solubilize it must be removed. The derivatization and regeneration steps in the production of rayon significantly add to the cost of this form of cellulose fiber. Consequently, in recent years attempts have been made to identify solvents that are capable of dissolving underivatized cellulose to form a dope of underivatized cellulose One class of organic solvents useful for dissolving cellulose are the amine N-oxides, in particular the tertiary amine N-oxides. For example, Graenacher, in U.S. Pat. No. 2,179,181, discloses a group of amine oxide materials suitable as solvents. Johnson, in U.S. Pat. No. 3,447,939, describes the use of anhydrous N-methylmorpholine-N-oxide (NMMO) and other amine N-oxides as solvents for cellulose and many other natural and synthetic polymers. Franks et al., in U.S. Pat. Nos. 4,145,532 and 4,196,282, deal with the difficulties of dissolving cellulose in amine oxide solvents and of achieving higher concentrations of cellulose.
[0007] Lyocell is an accepted generic term for a cellulose fiber precipitated from an organic solution in which no substitution of hydroxyl groups takes place and no chemical intermediates are formed. Several manufacturers presently produce lyocell fibers, principally for use in the textile industry. For example, Acordis, Ltd. presently manufactures and sells a lyocell fiber called Tencel® fiber.
[0008] Currently available lyocell fibers are produced from wood pulps that have been extensively processed to remove non-cellulose components, especially hemicellulose. These highly processed pulps are referred to as dissolving grade or high alpha (or high α) pulps, where the term alpha (or α) refers to the percentage of cellulose. Thus, a high alpha pulp contains a high percentage of cellulose, and a correspondingly low percentage of other components, especially hemicellulose. The processing required to generate a high alpha pulp significantly adds to the cost of lyocell fibers and products manufactured therefrom.
[0009] Since the conventional Kraft process stabilizes residual hemicelluloses against further alkaline attack, it is not possible to obtain acceptable high alpha pulps for lyocell products, through subsequent treatment of Kraft pulp in the conventional bleaching stages. In order to prepare high alpha pulps by the Kraft process, it is necessary to pretreat the wood chips in an acid phase before the alkaline pulping stage. A significant amount of material, primarily hemicellulose, on the order of 10% or greater of the original wood substance, is solubilized in this acid phase pretreatment and thus process yields drop. Under these conditions, the cellulose is largely resistant to attack, but the residual hemicelluloses are degraded to a much shorter chain length and are therefore removed to a large extent in the subsequent Kraft cook by a variety of hemicellulose hydrolysis reactions or by dissolution. The disadvantage of conventional high alpha pulps used for lyocell is the resulting loss of yield by having to eliminate hemicelluloses.
[0010] In view of the expense of producing commercial high alpha pulps, it would be desirable to have alternatives to conventional high alpha pulps for making lyocell products. In addition, manufacturers would like to minimize the capital investment necessary to produce such types of pulps by utilizing existing capital plants. Thus, there is a need for relatively inexpensive, low alpha (e.g., high yield, high hemicellulose) pulps that have attributes that render them useful in lyocell-molded body production.
[0011] In U.S. Pat. No. 6,210,801, fully incorporated herein by reference in its entirety, assigned to the assignee of the present application, low viscosity, high hemicellulose pulp is disclosed that is useful for lyocell-molded body production. The pulp is made by reducing the viscosity of the cellulose without substantially reducing the hemicellulose content. Such processes use an acid, or an acid substitute, or other methods therein described.
[0012] While the methods described in the '801 patent are effective at reducing the average degree of polymerization (D.P.) of cellulose without substantially decreasing the hemicellulose content, a further need existed for a process that did not require a separate copper number reducing step and which was readily adaptable to pulp mills that have oxygen reactors, multiple alkaline stages and/or alkaline conditions suitable for substantial D.P. reduction of bleached or semi-bleached pulp. Environmental concerns have also generated a great interest in using bleaching agents that reduce the use of chlorine compounds. In recent years, the use of oxygen as a delignifying agent has occurred on a commercial scale. Examples of equipment and apparatus useful for carrying out an oxygen stage delignification process are described in U.S. Pat. Nos. 4,295,927; 4,295,925; 4,298,426; and 4,295,926. In U.S. Pat. No. 6,331,554, assigned to the assignee of the present application, fully incorporated herein by reference in their entirety, a high hemicellulose, low viscosity pulp is disclosed that is useful for lyocell-molded body formation. The pulp is made from an alkaline pulp by treating the alkaline pulp with an oxidizing agent in a medium to high consistency reactor to reduce the D.P. of the cellulose, without substantially reducing the hemicellulose or increasing the copper number.
[0013] Further efforts to reduce the cost of making lyocell-molded bodies has resulted in U.S. application Ser. No. 09/842,274, fully incorporated by reference in its entirety. In the '274 application, the assignee of the present invention describes pulps made from sawdust and other low fiber length wood using a procedure similar to that of the '554 patent. These pulps are high in hemicellulose and low in viscosity, which makes them especially suitable for lyocell-molded body formation.
[0014] The forest industry continues to generate vast quantities of byproducts in the normal course of day-to-day forestry management and wood processing. These byproducts are for the most part underutilized. The need to conserve resources by utilizing wood byproducts in new ways presents a unique opportunity. It would be advantageous to develop a low cost pulp that is useful for making lyocell-molded bodies from all this underutilized wood, namely from the core wood or young or juvenile wood such as thinnings, hereafter referred to as low specific gravity wood. Thus, presenting a low cost alternative to the highly refined high-alpha pulps.
SUMMARY OF THE INVENTION
[0015] One embodiment of the invention is a pulp having at least 7% by weight hemicellulose; a viscosity of less than or about 32 cP; a copper number less than or about 2; a weighted average fiber length less than or about 2.7 mm; and a coarseness less than or about 23 mg/100 m. In another embodiment of the invention, a method for making lyocell-molded body is provided. The method includes dissolving a pulp in a solvent to form a cellulose solution; forming a lyocell-molded body from the solution; and regenerating the molded body, wherein the pulp has at least 7% by weight hemicellulose, a viscosity less than or about 32 cP; a copper number less than or about 2; a weighted average fiber length less than or about 2.7 mm; and a coarseness less than or about 23 mg/100 m. The method can use a meltblowing, centrifugal spinning, spun bonding, or dry-jet wet technique.
[0016] In another embodiment of the invention, a method of making a pulp is provided. The method includes pulping of wet material with a specific gravity less than or about 0.41 using an alkaline pulping process; and bleaching the pulp to reduce the viscosity of the pulp to or about 32 cP or lower. The bleached pulp has at least 7% hemicellulose by weight, a copper number less than or about 2, a weighted average fiber length less than or about 2.7 mm, and a coarseness less than or about 23 mg/100 m.
[0017] In another embodiment of the invention, a lyocell product is provided. The lyocell product has at least 7% hemicellulose by weight, and cellulose, wherein the pulp used to make the product has a viscosity less than or about 32 cP, a copper number less than or about 2, a weighted average fiber length less than or about 2.7 mm, and a coarseness less than or about 23 mg/100 m. Lyocell products can be fibers, films, or non-woven webs, for example.
[0018] The use of low specific gravity wood can produce a lower brownstock viscosity for a given kappa number target. Using wood with low specific gravity values reduce the bleach stage temperature and the chemical dose needed in the bleach plant to produce pulp having acceptable lyocell specifications. Low specific gravity wood results in very low viscosity levels without increasing the copper number of the pulp or the concentration of carbonyl in the pulp above acceptable levels. The process does not use an acid phase pretreatment prior to pulping, and the subsequent bleaching conditions do not result in a substantial decrease in hemicellulose content.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
[0020] [0020]FIG. 1 is a flowsheet illustrating one embodiment of a method of making a pulp according to the present invention; and
[0021] [0021]FIG. 2 is a flow sheet illustrating one embodiment of a method of making a lyocell-molded body according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] Referring now to FIG. 1, a suitable method to produce a lyocell dissolving pulp from low specific gravity wood is illustrated. The method may be considered to include two broad processing areas, pulping depicted as block 126 and bleaching depicted as block 128 .
[0023] In block 100 , low specific gravity wood chips are loaded or fed into a digester. Specific gravity, according to The Handbook of Pulping and Papermaking, 2d ed., by Christopher J. Biermann, is the (unit less) ratio of the solid wood density to the density of water at the same temperature. As used herein, specific gravity is the average specific gravity of any population or wood feedstock material. The solid wood density may be determined using the green volume, the oven-dry volume, or intermediate volumes. The wood chips used in practicing the invention can be made from any cellulose source. Contrary to conventional thinking, low specific gravity wood has been found to be suitable for use as a source of cellulose for making lyocell-molded bodies. A suitable range of low specific gravity wood used for the present invention is any wood material having a specific gravity about equal or less than 0.41. Low specific gravity wood results in a lower brownstock pulp viscosity, which is believed to reduce the use of bleaching chemicals in the bleach plant. Representative sources of low specific gravity wood may be derived from “thinnings” and “juvenile” wood. Juvenile wood is defined as the first 10 growth rings surrounding the pith, according to Biermann. However, others define it as wood formed near the pith of the tree, often characterized by wide growth rings, lower density, and shorter fibers. However, in some instances the juvenile wood may extend to the 15-ring or more. Specific gravity increases with the increasing height of the tree, so specific gravity at 16 feet, 32 feet, or 48 feet is incrementally greater than at the butt of the tree. In some embodiments, the specific gravity will be less than 0.41, and could be less than 0.38, 0.36, 0.34, 0.32, or 0.30, or less.
[0024] Digesters for use in the present invention can include any digester suitable to pulp low specific gravity wood. One example of a suitable digester is a continuous digester that is often referred to as a “Kamyr” digester. (It should be noted that Kamyr is the name of a Company that designed and built such digesters and as such, the term Kamyr is loosely associated with a continuous digester. Kamyr no longer exists as a Company. Such continuous digesters are supplied by Kvaerner.) These digesters have been used in the pulp and paper industry for several years with the first one being installed in Sweden in 1950. Over the years, the modifications have been made to these digesters to improve their operation. The digester system may be either a single vessel or a two-vessel system. “Kamyr” digesters are typically used in Kraft or alkaline wood pulping, but may also be used in semi-chemical pulping methods. Other continuous digesters, such as the M&D digester and the Pandia digester, are also suitable to use in the present invention. However, the present invention can also be practiced using any batch or other continuous digester.
[0025] Referring to FIG. 1, within the pulping process, block 126 , there are several operations, depicted as blocks 100 - 116 . Loading, or feeding chips as discussed above, occurs in block 100 . The wood chips may be presteamed prior to cooking, block 102 . Steam at atmospheric pressure preheats the chips and drives off air so that liquor penetration will be enhanced. After the pre-steaming operation is completed, cooking liquor, referred to as white liquor, containing the pulping chemicals may be added to the chips, block 104 . The white liquor and chips are then fed into the digester. In Kraft pulping, the active chemical compounds are NaOH and Na 2 S. Other chemicals may be added to influence or impart desirable effects on the pulping process. These additional chemicals are well known to those of skill in the art. The present invention provides a lower brownstock pulp viscosity from relatively lower specific gravity wood as composed with wood having a higher specific gravity, i.e., specific gravity is related to Kappa number.
[0026] Impregnation, block 106 , is the period during which the chemicals are allowed to impregnate the low specific gravity wood material. Good liquor penetration helps assure a uniform cooking of the chips.
[0027] “Cooking” occurs in blocks 108 and 110 . The co-current liquid contact operation, block 108 , is followed by the counter-current liquid contact operation, block 110 . Cooking of the low specific gravity wood occurs during these two operations. In either block 108 or 110 , the cooking liquor and chips can be brought to temperature.
[0028] Digester washing, block 112 , is accomplished by introducing wash liquor into the bottom of the digester and having it flow counter-current to the cooked pulp. Cooking for the most part ends when the pulp encounters the cooler wash liquor.
[0029] Upon completion of the cook operation, and digester washing, the digester contents are blown, block 112 . Digester blowing involves releasing the wood chips and liquor at atmospheric pressure. The release occurs with a sufficient amount of force to cause fiber separation. If desired, the blow tank may be equipped with heat recovery equipment to reduce operating expenses.
[0030] In block 114 , the pulp is sent from the blow tank to external brownstock pulp washers. The separation of black liquor from the pulp occurs at the brownstock washers.
[0031] In one embodiment of a method of making a pulp from low specific gravity wood to be used in the manufacture of lyocell-molded bodies, the time allowed for impregnation in block 106 is about 35 minutes. The initial percent effective alkali is about 8.5. The percent effective alkali at 5 minutes is about 1.6. The percent sulfidity is about 29. The liquor ratio is about 4. The initial temperature is about 110° C. The residual grams per liter of effective alkali is about 9.63. The residual percent effective alkali is about 3.85. The pH is about 12.77, and the H factor is about 2.
[0032] In one embodiment of the co-current operation, block 108 , the percent effective alkali is about 4.2. According to Biermann, the effective alkali is the ingredients that will actually produce alkali under pulping conditions. The percent sulfidity is about 29. According to Biermann, the sulfidity is the ratio of sodium sulfide to the active alkali, expressed as a percent. The liquor addition time is about 1 minute. The temperatures may be ramped to the final cooking temperature with a hold at one or more temperatures. The first temperature platform is about 154° C. The time to reach the temperature is about 9 minutes and the time at the temperature is about 5 minutes. A second and higher cooking temperature at the co-current operation is provided at 170° C. The time to reach the second temperature is about 51 minutes and the time at temperature is about 3 minutes. The effective alkali remaining after a cook operation is called the residual alkali. The residual grams per liter of effective alkali is about 9.42, following the co-current operation. The residual percent effective alkali is about 3.77. The pH is about 12.92, and the H factor is about 649.
[0033] In one embodiment of the counter-current operation, block 110 , the percent effective alkali is about 8. The percent sulfidity is about 29.2. Capability also exists for ramping to two different temperatures in the counter-current step. However, in one embodiment, the first and second cooking temperatures are both about 171° C. The time to reach temperature is about 54 minutes and the time at the temperature is about 162 minutes. The effective alkali grams per liter is about 16.0. The displacement rate is about 93 ml per minute. The displacement volume is about 20 liters. The volumes given here are relatively small, since the method was tested on a lab-scale bench reactor. However, with the parameters provided herein, and with no undue experimentation, the process can be scaled to any rate. The residual grams per liter of effective alkali is about 9.95. The residual percent effective alkali is about 3.98. The pH is about 12.74 and the H factor is about 3877. In one embodiment, the total time is about 319 minutes and the percent effective alkali for the total cook is about 22.3.
[0034] In one embodiment, after washing, the viscosity of the brownstock pulp is about 153 cP. The total yield on oven dried wood is about 41.04.
[0035] Following the pulping process, generally depicted as reference numeral 126 in FIG. 1, the brownstock pulp made from low specific gravity wood is bleached to reduce its viscosity. The bleaching process does not lead to a substantial reduction of the hemicellulose content of the pulp. The method according to the invention produces a bleached dissolving pulp that is suitable for lyocell-molded body production. Bleaching of chemical pulps involves the removal of lignin with an attendant decrease in the pulp fiber length and viscosity. However, the bleaching process does not cause a substantial reduction to the hemicellulose content of the pulp. Bleaching brownstock pulp made from low specific gravity wood may require fewer chemicals than the conventional highly refined, high-alpha pulps presently being used for lyocell.
[0036] In one embodiment, the low specific gravity brownstock pulp made according to the invention can be treated with various chemicals at different stages in the bleach plant. The stages are carried out in vessels or towers of conventional design. One representative bleaching sequence is ODE p D. The operations occurring in the bleaching plant are represented collectively by reference numeral 128 in FIG. 1. Other embodiments of post bleaching the pulp after pulping are described in U.S. Pat. No. 6,331,354, and U.S. application Ser. No. 09/842,274, incorporated herein by reference in their entirety.
[0037] The first stage of bleaching is an O stage, block 116 . The O stage comprises bleaching with oxygen. However, according to Biermann, some consider oxygen bleaching to be an extension of the pulping process. Oxygen bleaching is the delignification of pulps using oxygen under pressure. The oxygen is considered to be less specific for the removal of lignin than the chlorine compounds. Oxygen bleaching takes place in an oxygen reactor. Suitable oxygen reactors capable of carrying out the method of the present invention are described in U.S. Pat. Nos. 4,295,925; 4,295,926; 4,298,426; and 4,295,927, fully incorporated herein by reference in their entirety. The reactor can operate at a high consistency, wherein the consistency of the feedstream to the reactor is greater than 20% or it can operate at medium consistency, where the medium consistency ranges between 8% up to 20%. Preferably, if a high consistency oxygen reactor is used, the oxygen pressure can reach the maximum pressure rating for the reactor, but more preferably is greater than 0 to about 85 psig. In medium consistency reactors, the oxygen can be present in an amount ranging from greater than 0 to about 100 pounds per ton of the pulp, but is more preferably about 50 to about 80 pounds per ton of pulp. The temperature of the O stage ranges from about 100° C. to about 140° C.
[0038] In one embodiment of the method to make a pulp suitable to be used in making lyocell-molded bodies, a D stage, block 118 follows the O stage, block 116 . The D stage comprises bleaching the pulp coming from the oxygen reactor with chlorine dioxide. Chlorine dioxide is more selective than oxygen for removing lignin. The amount of chlorine dioxide used in this stage ranges from about 20 to about 30 lb/ton, which may be lower than a conventional bleach plant that processes pulp from wood chips with a specific gravity not within the low specific gravity range of this invention. The temperature of the D stage ranges from about 50° C. to about 85° C.
[0039] In one embodiment of the method to make a pulp suitable to be used in making lyocell-molded bodies, an E p stage, block 120 , follows the D stage, block 118 . The E p stage is the hydrogen peroxide reinforced extraction stage where lignin is removed from the pulp using caustic in an amount ranging from about 20 to about 50 lb/ton. The amount of hydrogen peroxide ranges from about 20 to about 60 lb/ton, which may be lower than a conventional bleach plant that processes pulp from wood chips having a specific gravity not considered within the low specific gravity range of this invention. The temperature of the E p stage ranges from about 75 to about 95° C.
[0040] In one embodiment, a second D stage, block 122 , follows the E p stage, block 120 . The amount of chlorine dioxide used in this stage ranges from 10 to about 30 lb/ton, which may be lower than a conventional bleach plant that processes pulp from wood chips having a conventional specific gravity not considered to be within the low specific gravity range of this invention. The temperature of the D stage ranges from about 60° C. to about 90° C.
[0041] One embodiment of a pulp made from low specific gravity wood has a hemicellulose content of at least 7% hemicellulose, a pulp viscosity less than 32 cP, a copper number less than 2.0, and in some instances less than 1.3 (TAPPI T430), a weighted average fiber length less than 2.7 mm, and a coarseness less than 23 mg/100 m. Other embodiments of pulps made according to the present invention have a combined copper, manganese, and iron content less than 2 ppm, a total metal load less than 300 ppm, and a silicon content less than 50 ppm. Lyocell molded bodies made from the pulps of the invention will have correspondingly high hemicellulose content of at least 7% by weight, and cellulose.
[0042] Hemicellulose is measured by a sugar content assay based on TAPPI standard T249 hm-85.
[0043] Methods for measuring pulp viscosity are well known in the art, such as TAPPI T230. Copper number is a measure of the carboxyl content of pulp. The copper number is an empirical test used to measure the reducing value of cellulose. The copper number is expressed in terms of the number of milligrams of metallic copper, which is reduced from cupric hydroxide to cuprous oxide in an alkaline medium by a specified weight of cellulosic material. The degree to which the copper number changes during the bleaching operation is determined by comparing the copper number of the brownstock pulp entering the bleaching plant and the copper number of the bleached pulp after the bleaching plant. A low copper number is desirable because it is generally believed that a high copper number causes cellulose and solvent degradation during and after dissolution of the bleached pulp to form a dope.
[0044] The weighted average fiber length (WAFL) is suitably measured by a FQA machine, model No. LDA93-R9704, with software version 2.0, made by the Optest Company of Hawkesbury, Ontario, Canada.
[0045] Coarseness is measured using Weyerhaeuser Standard Method WM W-FQA.
[0046] Transition metals are undesirable in pulp because they accelerate the degradation of cellulose and NMMO in the lyocell process. Examples of transition metals commonly found in bleached pulps include iron, copper, and manganese. Preferably, the combined metal content of these three metals in the pulps of the invention is less than about 20 ppm by Weyerhaeuser Test No. AM5-PULP-1/6010.
[0047] Additionally, pulps of the invention have a total metal load of less than 300 ppm by Weyerhaeuser Test No. AM5-PULP-1/6010. The total metal load refers to the combined amount, expressed in units of parts per million (ppm), of nickel, chromium, manganese, iron and copper.
[0048] Once the pulp has been bleached to reduce its viscosity without substantially increasing its copper number or decreasing the hemicellulose content, the pulp can either be washed in water and transferred to a bath of organic solvent, such as N-methyl-morpholine-N-oxide (NMMO), for dissolution prior to lyocell-molded body formation. Alternatively, the bleached washed pulp call be dried and broken into fragments for storage and/or shipping in a roll, sheet or bale, for example.
[0049] In order to make lyocell products from the low specific gravity wood pulps, the pulp is first dissolved in an amine oxide, preferably a tertiary amine oxide. Representative examples of amine oxide solvents useful in the practice of the present invention are set forth in U.S. Pat. No. 5,409,532, incorporated herein by reference in its entirety. The preferred amine oxide solvent is NMMO. Other representative examples of solvents useful in the practice of the present invention include dimethylsulfoxide (D.M.S.O.), dimethylacetamide (D.M.A.C.), dimethylformamide (D.M.F.) and caprolactan derivatives. The bleached pulp is dissolved in amine oxide solvent by any known means such as ones set forth in U.S. Pat. Nos. 5,534,113; 5,330,567; and 4,246,221, incorporated herein by reference in their entirety. The pulp solution is called dope. The dope is used to manufacture lyocell fibers, films, and nonwovens or other products, by a variety of techniques, including melt blowing, spun-bonding, centrifugal spinning, dry-jet wet, or any other suitable method. Examples of some of these techniques are described in U.S. Pat. Nos. 6,235,392; 6,306,334; 6,210,802; and 6,331,354, incorporated herein by reference in their entirety. Examples of techniques for making films are set forth in U.S. Pat. Nos. 5,401,447; and 5,277,857, incorporated herein by reference in their entirety. Meltblowing, centrifugal spinning and spunbonding used to make lyocell fibers and nonwoven webs are described in U.S. Pat. Nos. 6,235,392 and 6,306,334, incorporated herein by reference in their entirety. Dry-jet wet techniques are more fully described in U.S. Pat. Nos. 6,235,392; 6,306,334; 6,210,802; 6,331,354; and 4,142,913; 4,144,080; 4,211,574; 4,246,221; incorporated herein by reference in their entirety.
[0050] One embodiment of a method for making lyocell products, including fibers, films, and nonwoven webs from dope derived from pulp is provided, wherein the pulp is made from low specific gravity wood, the pulp having at least 7% hemicellulose, a viscosity less than or about 32 cP, a copper number less than or about 2, a weighted average fiber length less than or about 2.7 mm, and a coarseness less than or about 23 mg/100 m. The method involves extruding the dope through a die to form a plurality of filaments, washing the filaments to remove the solvent, regenerating the filaments with a nonsolvent, including water or alcohol, and drying the filaments.
[0051] [0051]FIG. 2 shows a block diagram of one embodiment of a method for forming lyocell fibers from the pulps made from low specific gravity wood according to the present invention. Starting with low specific gravity wood pulp in block 200 , the pulp is physically broken down, for example by a shredder in block 202 . The pulp is dissolved with an amine oxide-water mixture to form a dope, block 204 . The pulp can be wetted with a nonsolvent mixture of about 40% NMMO and 60% water. The mixture can be mixed in a double arm sigma blade mixer and sufficient water distilled off to leave about 12-14% based on NMMO so that a cellulose solution is formed, block 208 . Alternatively, NMMO of appropriate water content may be used initially to eliminate the need for the vacuum distillation block 208 . This is a convenient way to prepare spinning dopes in the laboratory where commercially available NMMO of about 40-60% concentration can be mixed with laboratory reagent NMMO having only about 3% water to produce a cellulose solvent having 7-15% water. Moisture normally present in the pulp should be accounted for in adjusting the water present in the solvent. Reference is made to articles by Chanzy, H., and A. Peguy, Journal of Polymer Science, Polymer Physics Ed. 18:1137-1144 (1980), and Navard, P., and J. M. Haudin, British Polymer Journal, p. 174 (December 1980) for laboratory preparation of cellulose dopes in NMMO and water solvents.
[0052] The dissolved, bleached pulp (now called the dope) is forced through extrusion orifices in a process called spinning, block 210 , to produce cellulose filaments that are then regenerated with a non-solvent, block 202 . Spinning to form lyocell-molded bodies, including fibers, films, and nonwovens, may involve meltblowing, centrifugal spinning, spun bonding, and dry-jet wet techniques. Finally, the lyocell filaments or fibers are washed, block 214 .
[0053] The solvent can either be disposed of or reused. Due to its high costs, it is generally undesirable to dispose of the solvent. Regeneration of the solvent suffers from the drawback that the regeneration process involves dangerous, potentially explosive conditions.
[0054] The following examples merely illustrate the best mode now contemplated for practicing the invention, but should not be construed to limit the invention.
EXAMPLE 1
[0055] A commercial continuous extended delignification process was simulated in the laboratory utilizing a specially built reactor vessel with associated auxiliary equipment, including circulating pumps, accumulators, and direct heat exchangers, etc. Reactor temperatures were controlled by indirect heating and continuous circulation of cooking liquor. The reactor vessel was charged with a standard quantity of equivalent moisture free wood. An optional atmospheric pre-steaming step may be carried out prior to cooking. A quantity of cooking liquor, ranging from about 50% to 80% of the total, was then charged to the digester along with dilution water to achieve the target liquor to wood ratio. The reactor was then brought to impregnation temperature and pressure and allowed to remain for the target time. Following the impregnation period, an additional portion of the total cooking liquor was added to the reactor vessel, ranging from about 5% to 15% of the total. The reactor was then brought to cooking temperature and allowed to remain there for the target time period to simulate the co-current portion of the cook.
[0056] Following the co-current portion of the cook, the remainder of the cooking liquor was added to the reactor vessel at a fixed rate. The rate is dependent on the target time period and proportion of cooking liquor used for this step of the cook. The reactor was controlled at a target cooking temperature and allowed to remain there during the simulation of the counter-current portion of the cook. Spent cooking liquor was withdrawn from the reactor into an external collection container at the same fixed rate. At the end of the cook, the reactor vessel was slowly depressurized and allowed to cool below the flash point. The reactor vessel was opened and the cooked wood chips were collected, drained of liquor, washed, screened and made ready for testing. Three cooks of low specific gravity wood chips were prepared, along with three cooks of non-low specific gravity wood.
EXAMPLE 2
Pulping Process Parameters for Low Specific Gravity Wood
[0057] One cook for low specific gravity wood chips had the following parameters.
TABLE 1 Wood Chip S.G. 0.410 Pre-Steam @ 110 C., minutes 5 Impregnation: Time, minutes 35 % Effective Alkali, initial 8.5 % EA, second @ 5 minutes 1.6 % sulfidity 29 Liquor ratio 4 Temperature-degrees C. 110 Residual, G/L EA 9.63 Residual, % EA 3.85 PH 12.77 H-factor 2 Pressure Relief Time, Minutes 3 Co-Current: % Effective Alkali 4.2 % sulfidity 29 liquor addition time, minutes 1 temperature-degrees C. 154 time to, minutes 9 time at, minutes 5 temperature-degrees C. 170 time to, minutes 51 time at, minutes 3 residual, G/L EA 9.42 residual, % EA 3.77 PH 12.92 H-Factor 649 Counter-Current: % effective alkali 8 % sulfidity 29.2 temperature-degrees C. 171 time to, minutes 54 time at, minutes 0 temperature-degrees C. 171 time to, minutes 0 time at, minutes 162 EA, G/L-strength 16.0 displacement rate, CC/M 93 displacement volume, liters 20.00 residual, G/L EA 9.95 residual, % EA 3.98 PH 12.74 H-factor 3877 Total Time, Minutes 319 % Effective Alkali-Total Cook 22.3 Accepts, % on O.D. Wood 41.01 Rejects, % on O.D. Wood 0.03 Total Yield, % on O.D. Wood 41.04 Kappa Number, 10 Minutes 16.80
EXAMPLE 3
Bleaching Process for Low Specific Gravity Wood
[0058] The pulp made by the process of Example 2 was bleached according to the following procedure.
[0059] O Stage
[0060] Inwoods low specific gravity wood chips were pulped into an alkaline Kraft pulp with a kappa number of 16.8 (TAPPI Standard T236 cm-85 and a viscosity of 239 cP (TAPPI T230). The brownstock pulp was treated with oxygen in a pressure vessel with high consistency mixing capabilities. The vessel was preheated to about 120° C. An amount of sodium hydroxide (NaOH) equivalent to 100 pounds per ton of pulp was added to the alkaline pulp. The reaction vessel was then closed and the pressure was increased to 60 psig by introducing oxygen into the pressure vessel. Water was present in the vessel in an amount sufficient to provide a 10% consistency.
[0061] After 45 minutes, the stirring was stopped and the pulp was removed from the pressure vessel and washed. The resulting washed pulp viscosity was 35.3 cP, and had a kappa number of 3.8.
[0062] D Stage
[0063] The D stage treated the pulp processed in the O stage by washing it three times with distilled water, pin fluffing the pulp, and then transferring the pulp to a polypropylene bag. The consistency of the pulp in the polypropylene bag was adjusted to 10% with the addition of water. Chlorine dioxide corresponding to an amount equivalent to 28.4 pounds per ton of pulp was introduced to the diluted pulp by dissolving the chlorine dioxide in the water used to adjust the consistency of the pulp in the bag. The bag was sealed and mixed and then held at 75° C. for 30 minutes in a water bath. The pulp was removed and washed with deionized water.
[0064] E p Stage
[0065] The washed pulp from the D stage was then placed in a fresh polypropylene bag and caustic was introduced with one-half of the amount of water necessary to provide a consistency of 10%. Hydrogen peroxide was mixed with the other one-half of the dilution water and added to the bag. The hydrogen peroxide charge was equivalent to 40 pounds per ton of pulp. The bag was sealed and mixed and held for 55 minutes at 88° C. in a water bath. After removing the pulp from the bag and washing it with water, the mat was filtered and then placed back into the polypropylene bag and broken up by hand.
[0066] D Stage
[0067] Chlorine dioxide was introduced a second time to the pulp in an amount equivalent to 19 pounds per ton of pulp with the dilution water necessary to provide a consistency of 10%. The bag was sealed and mixed, and then held for 3 hours at 88° C. in a water bath. The treated pulp had a copper number of about 0.9 measured by TAPPI Standard T430 and had a hemicellulose (xylan and mannan) content of 12.7%.
EXAMPLE 4
[0068] Low specific gravity wood having a specific gravity of 0.410 was pulped using the Kraft process, and subsequently, bleached and treated with varying amounts of oxygen to reduce its viscosity. Components in the pulps made using Inwoods low specific gravity wood chips are 7.2% xylans and 5.5% mannans.
[0069] Table 2 shows the results for three different cooking conditions. While brownstock pulp WAFL is provided, it is apparent that bleaching the brownstock pulp to reduce its viscosity without substantially reducing the hemicellulose content, in accordance with the conditions of the present invention, will not result in any appreciable increase in the bleached pulp WAFL and may in fact be lower than the brownstock pulp WAFL.
TABLE 2 Inwoods chips Inwoods chips Inwoods chips Cook A Cook B Cook C Chips Specific Gravity 0.410 0.410 0.410 Kappa of Brownstock 24.4 20.1 16.8 Yield % 43.2 41.4 41.0 Brownstock pulp 414 235 153 viscosity (cP) Falling Ball Brownstock pulp 2.70 2.70 2.69 WAFL (mm) Brownstock pulp 18.3 17.9 17.6 Coarseness (mg/100 m) O2 pulp viscosity cP 55 34 28 (100 lbs/ton NaOH) 7.6 kappa 6.0 kappa 3.8 kappa O2 pulp viscosity cP 80 63 49 (60 lbs/ton NaOH) 6.0 kappa 7.5 kappa 5.6 kappa Bleached pulp 32.4 21.8 coarseness (mg/100 m) Bleached pulp fibers/ 4.8 4.6 g x 10 6 Bleached pulp 31.8 29.5 viscosity (cP) Bleached pulp intrinsic 4.1 4.2 viscosity Bleached pulp 0.6 <0.6 Cu (ppm) Bleached pulp 12 14.3 Fe (ppm) Bleached pulp 1.5 3.6 Mn (ppm) Bleached pulp <0.4 <0.3 Cr (ppm) Bleached pulp 41 31 Si (ppm)
COMPARATIVE EXAMPLE 5
Pulping Process Parameters for Non-Low Specific Gravity Wood
[0070] A conventional Tolleson wood chip made from wood having specific gravity of 0.495 was pulped using a Kraft process and subsequently treated with varying amounts of oxygen to reduce its viscosity. Table 3 shows the pulping conditions for one cook of Tolleson wood chips.
TABLE 3 Wood Chips S.G. 0.495 Pre-Steam @ 110 C., minutes 5 Impregnation: time, minutes 35 % Effective Alkali, initial 8.5 % EA, second @ 5 minutes 1.6 % sulfidity 30.5 liquor ratio 4 temperature-degrees C. 110 residual, G/L EA 9.17 residual, % EA 3.67 PH 13.24 H-factor 2 Pressure Relief Time, Minutes 2 Co-Current: % Effective Alkali 4.2 % sulfidity 30.5 liquor addition time, minutes 1 temperature-degrees C. 157 time to, minutes 14 time at, minutes 0 temperature-degrees C. 170 time to, minutes 54 time at, minutes 0 residual, G/L EA 8.31 residual, % EA 3.32 PH 13.07 H-Factor 680 Counter-Current: % Effective Alkali 8 % sulfidity 30.0 Temperature-degrees C. 171 Time to, minutes 54 Time at, minutes 0 Temperature-degrees C. 171 Time to, minutes 0 Time at, minutes 162 EA, G/L-strength 20.4 Displacement rate, CC/M 73 Displacement volume, liters 15.87 Residual, G/L EA 9.72 residual, % EA 3.89 PH 13.18 H-factor 3975 Total Time, Minutes 319 % Effective Alkali-Total Cook 22.3 Accepts, % on O.D. Wood 44.23 Rejects, % on O.D. Wood 0.13 Total Yield, % on O.D. Wood 44.36 Kappa Number, 10 Minutes 17.75
[0071] Table 4 shows the results of three different cooks using a conventional Tolleson wood chip made from a non-low specific gravity wood. Components in the pulps made using Tolleson non-low specific gravity wood chips are 6.5% xylose; 6.6% mannose; 5.7% xylans; and 5.9% mannans.
TABLE 4 Tolleson chips Tolleson chips Tolleson chips Cook A Cook B Cook C Chips Specific Gravity 0.495 0.495 0.495 Kappa of Brownstock 26.9 20.8 17.8 Yield % 46.6 46.1 44.4 Brownstock pulp 633 358 243 viscosity (cP) Falling Ball Brownstock pulp 4.13 4.14 4.19 WAFL (mm) Brownstock pulp 26.1 24.4 24.3 Coarseness (mg/100 m) O2 pulp viscosity cP 96 43 41 (100 lbs/ton NaOH) 6.4 kappa 6.9 kappa 4.7 kappa O2 pulp viscosity cP 180 88 70 (60 lbs/ton NaOH) 8.3 kappa 5.5 kappa 6.2 kappa Bleached pulp 24.9 27.5 coarseness (mg/100 m) Bleached pulp 3.8 2.8 fibers/g x 10 6 Bleached pulp 28.5 24.2 viscosity (cP) Bleached pulp intrinsic 4.3 4 viscosity Bleached pulp Cu <0.6 <0.7 (ppm) Bleached pulp Fe 11.5 16 (ppm) Bleached pulp Mn 5 6 (ppm) Bleached pulp Cr <0.4 0.3 (ppm) Bleached pulp Si ≧1 32 (ppm)
[0072] It can be seen that the viscosity of the pulps made from the Inwoods low specific gravity wood chips is lower than the viscosity of the pulps made from the Tolleson non-low specific gravity wood chips.
[0073] It can be seen that the viscosity of the pulps made from the Inwoods low specific gravity wood chips is lower than the viscosity of the pulps made from the Tolleson non-low specific gravity wood chips.
[0074] While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. | 4y
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 10/067,465, filed on Feb. 4, 2002, entitled “Method And Circuit For Processing Data In Communication Networks”, which is hereby expressly incorporated by reference for all purposes.
BACKGROUND OF THE INVENTION
The invention relates to the field of data processing in communications networks and more specifically to a method and circuit for detecting standard patterns in data such as those found in header bytes SONET-based telecommunication systems.
In some telecommunication systems, data is transmitted with a predetermined structure called the frame. The frame typically contains a header (or overhead) section where information about the particular flame resides, and a payload section where the actual data resides. Different data transmission protocols may required different data frame. For example, SONET (Synchronous Optical Network) which is a transmission multiplexing standard for high-speed data communications within North America, has as its basic building block a 51.84 Mb/s, OC-1 (Optical Carrier 1) flame. The organization of an OC-1 frame 24 is depicted in FIG. 7 . The structure of the OC-1 frame 24 can be thought of as a two dimensional matrix having nine rows 25 with each row 25 containing 90 bytes of data. The flame's data is transmitted row by row, from left to right with the most significant bit (MSB) of each byte being transmitted first The first three columns of each frame form the header section that is divided between section overhead 26 and line overhead 27 as shown. The remainder of the flame carries the synchronous payload envelope (SPE) 28 containing the data. The section overhead 26 includes a series of named bytes. Two of the named bytes, A1 and A2 signal the start of the OC-1 frame. According to the SONET standard, the A1 byte has a value F6 in hexadecimal (1111 — 0110 in binary) and the A2 byte has a value of 28 (0010 — 1000 in binary).
To achieve high data rates, multiple frame-aligned OC-1 signals are multiplexed to form a higher frequency OC-N signal. FIG. 7 shows an OC-N signal 23 which is made up of N OC-1 frames ( 24 , 24 a , 24 b , etc.). The OC-N signal 23 allows the system to operate at a frequency of (N)×(51.84 Mb/s). As shown in FIG. 7 , the OC-N signal 23 can be viewed as a three dimensional frame having a depth of N tiers, each of which is an OC-1 frame 24 . In SONET, data is transmitted serially with the sequence of byte transmission indexed first by tier depth N then by row then by column. So the A1 byte of OC-1 frame 24 would be transmitted first, followed by the A1 byte of OC-1 frame 24 a , followed by the A1 byte of OC-1 frame 24 b , etc. After the A1 bytes of all N OC-1 frames are transmitted, the sequence steps along the row, and the A2 bytes of the OC-1 frames, 24 , 24 a , 24 b , etc. are transmitted. The beginning pattern for an OC-N SONET signal is thus N consecutive A1 bytes (A1=F6) followed by N consecutive A2 bytes (A2=28). This distinctive sequence must be detected by a SONET receiver in order to distinguish the start of an OC-N frame.
At the receiver end, the serial SONET data is first deserialized from a serial bitstream onto a multiple-bit (e.g., 16 bit) wide parallel data bus by a SERDES (Serializer/Deserializer) chip. The 16 bit wide bus is then further deserialized into a 128-bit wide parallel bus for data processing in an OC-N framer chip. Since data arrives from the optical fiber as a serial bitstream, the data on the 128 bit bus, after the two deserializing steps, may not fall on the A1A2 boundary. A method is needed to rearrange the data and align it in such a way that the data aligns along the A1A2 boundary.
Several methods of accomplishing this data alignment are known in the art. For example, one known method compares the 128 bits of data on the data bus with A1 and A2 directly. As the A1A2 boundary can fall on any of the 128 bits, detecting the A1A2 boundary in one clock cycle according to this method requires 128, 128-bit comparators. The circuitry needed to accomplish detection of the A1A2 boundary according to this method is too large to be commercially practicable. Assuming state of the art 0.18 micron process technology, a single 128 bit comparator has about 4,500 unit cells. Implementation of 128 such comparators would thus require 756,000 unit cells. Realignment by this method would also require 128, 128-to-1 multiplexers, each of which requires 3,000 unit cells to implement. The total unit cell cost of the known direct comparison method is 1,100,000 unit cells, which is quite expensive.
An alternative method requires only one 128-bit comparator which directly compares the 128-bit data bus with A1 and A2. In order to cover all possible locations of the A1A2 boundary, this second method shifts the 128-bit register one bit between every comparison until the boundary is found. This method has the advantage of requiring much less circuitry to implement, but requires potentially 128 clock cycles to detect the A1A2 boundary. Such a long delay is not acceptable in real time data processing.
A third method for detecting the A1A2 boundary moves the detection logic one level closer to the line level. If detection can be performed at the input to the OC-N framer, on a 16-bit wide bus, unit cell savings can be realized. The shortcoming with this method is that the comparison has to be made at a much higher clock frequency (622 MHz), which is a difficult timing requirement to meet.
What is needed is a method and circuitry for detecting data patterns such as the A1A2 boundary in an OC-N SONET frame using a small number of clock cycles and minimal circuit overhead.
BRIEF SUMMARY OF THE INVENTION
The present invention provides methods and circuitry for detecting standard patterns in received data such as the A1A2 boundary in a SONET frame. In a specific embodiment, the present invention detects the SONET frame A1A2 boundary and realigns the data along the A1A2 boundary in as little as five clock cycles with a minimum of logic circuitry.
A method according to embodiments of the present invention detects the A1A2 boundary by monitoring half the bytes on a data bus for two consecutive clock cycles. The boundary is detected if all of the monitored bytes for the first cycle equal A1*, which is A1 or any bit shifted value thereof, and all of the monitored bytes for the subsequent cycle equal A2*, which is A2 or any bit shifted value thereof. Aspects of the present invention provide for storing the first set of data bus values in a first data register to facilitate the comparison. Another aspect of the invention allows detection of the A1A2 boundary on a 128-bit bus. Additional aspects of the invention enable detection of the A1A2 boundary in any OC-N SONET frame. Other aspects of the invention allow for detection of the A1A2 boundary by monitoring 8 bytes on the data bus per clock cycle.
A method according to the present invention is provided for bit shifting SONET data on a data bus such that each byte on the shifted bus equals either A1 or A2. Other aspects of the present invention apply the bit shifting method to a 128-bit wide data bus. In some aspects of the present invention, 8 bytes of data on the data bus are compared with predetermined values for each of two clock cycles in order to determine the extent to which the output bus should be bit shifted.
Other aspects of the present invention are provided for byte shifting data on a SONET data bus such that all the bytes of at least one clock cycle are equal to A1 and all the bytes of on the bus during a subsequent clock cycle are all equal to A2.
According to one embodiment of the present invention circuitry for detecting the A1A2 boundary in a SONET frame includes a first data register for storing the values on a SONET data bus and a comparator for comparing some portion of the stored values with a set of predetermined values and for comparing some portion of the data bus values with predetermined values. Other aspects of the present invention provide a bit select output from a comparator, the value of the bit select being determined by the difference between the values of bytes in the first data register and predetermined values. Other aspects of the present invention provide a second data register coupled to the first data register for storing the first data register's values on a subsequent clock cycle.
Other embodiments of the present invention provide a bit shifter for mapping a SONET data bus onto a new bus such that each SONET header byte in the new bus equals either A1 or A2. Other aspects of the present invention provide for the bit shifter to take input from the bit select as well as from the first and second data registers. Another embodiment of the present invention includes a bit shifter realized as an array of multiplexers. Another embodiment of the present invention provides a third data register to store the bit shifted bus and a fourth data register to store the values in the third data register on a subsequent clock cycle.
Alternate embodiments of the present invention shift data on a SONET data bus such that the data are aligned along the A1A2 boundary. Some aspects of the present invention provide a byte selection circuitry that takes input from the third data register to determine the location of the A1A2 boundary with respect to the edge of the SONET data bus. Other embodiments provide that the byte select circuitry outputs a byte select bus. Other aspects of the present invention provide a byte shifter that takes as input the byte select bus as well as the outputs of the third and fourth data register, and outputs a new data bus, byte shifted such that bus data are aligned along the A1A2 boundary. Alternative embodiments of the invention provide a fifth data register to store the aligned bus values prior to output
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a datapath block diagram illustrating an A1A2 boundary detection technique according to an embodiment of the present invention;
FIG. 2 shows the time varying states of the two data registers of FIG. 1 as well as the contents of the incoming 128-bit data bus;
FIG. 3 shows a datapath block diagram of bit realignment of the data bus according an embodiment of the present invention;
FIG. 4 shows the states of two data registers comprising bit aligned data according to an embodiment of the present invention;
FIG. 5 shows a datapath block diagram of byte realignment according to an embodiment of the present invention;
FIG. 6 shows the time varying contents of a data register containing data aligned in accordance to the A1A2 boundary according to an embodiment of the present invention;
FIG. 7 shows a graphical depiction of an OC-N SONET frame;
FIG. 8 shows the A1A2 detection method when the A1A2 boundary is in the upper half of the input bus;
FIG. 9 shows the A1A2 detection method when the A1A2 boundary is in the lower half of the input bus; and
FIG. 10 is a block diagram of a SONET line card with including a framer operating according to an exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1 , there is shown a simplified datapath block diagram for detecting the A1A2 boundary in a SONET frame according to one embodiment of the present invention. Serial data P0[127:0] arrives on an input line 1 after having undergone optical-to-electrical conversion. The incoming data P0[127:0] is loaded sequentially into two multi-bit (e.g. 128 bit) data registers, DataReg 1 6 and DataReg 2 7 as shown. Various specific embodiments of the present invention are described herein in the context of a SONET framer implemented using 128 bit wide bus. It is to be understood, however, that the specific bus width or other implementation-specific values and numbers provided herein are for illustrative purposes only, and that the invention applies to telecommunication systems with other implementations. In the exemplary implementation shown in FIG. 1 , each of the registers DataReg 1 6 and DataReg 2 7 is a 128 bit register accommodating 16 8-bit bytes of data. The registers are designed to store two consecutive 128-bit data with DataReg 2 storing the first 128-bit data, and DataReg 1 storing the immediately following 128-bit data. Breaking down the data stream into pairs of bytes, the data flow in time at the inputs and outputs of the registers is as follows:
P2[127:112], P2[111:96], P2[95:80], P2[79:64], P2[63:48], P2[47:32], P2[31:16], P2[15:0],
P1[127:112], P1[111:96], P1[95:80], P1[79:64], P1 [63:48], P1[47:32], P1[31:16], P1[15:0],
P0[127:112], P0[111:96], P0[95:80], P0[79:64], P0[63:48], P0[47:32], P0[31:16], P0[15:0],
where P2[127:112] arrives at the framer's input first, and P0[15:0] arrives at the framer's input last.
FIG. 2 provides a depiction of the data flow through the registers in time. A lower block 110 of 64 bits of P0[127:0] data on the data input line 1 is defined by byte number 9 and below, and an upper block 100 of 64 bits of P1 [127:0] data is defined by byte number 10 and above, as shown. These 64 bit blocks are designated P0[63:0] 110 and P1[127:64] 100, respectively. In terms of the sequence of arrival, P1[127:64] 100 arrives first, followed by P1[63:0] 101, followed by P0[127:64] 111, followed by P0[63:0] 110. When the header of an OC-N frame arrives, at some point in time, each byte in P0[63:0] 110 will have a value of A2* and each byte in P1[127:64] 100 will have a value of A1*. A2* is either A2 itself, or A2 bit shifted in binary. A1* is either A1 itself or A1 bit shifted in binary. In the exemplary embodiment described herein, A1* is defined as any of the following binary values: A1 itself: 1111 — 0110, A1 left shifted 1 bit: 1110 — 1101, A1 left shifted 2 bits: 1101 — 1011, A1 left shifted 3 bits: 1011 — 0111, A1 left shifted 4 bits: 0110 — 1111, A1 left shifted 5 bits: 1101 — 1110, A1 left shifted 6 bits: 1011 — 1101, or A1 left shifted 7 bits: 0111 — 1011. Similarly, A2* is defined as any of the following binary values: A2 itself: 0010 — 1000, A2 left shifted 1 bit: 0101 — 0000, A2 left shifted 2 bits: 1010 — 0000, A2 left shifted 3 bits: 0100 — 0001, A2 left shifted 4 bits: 1000 — 0010, A2 left shifted 5 bits: 0000 — 0101, A2 left shifted 6 bits: 0000 — 1010, or A2 left shifted 7 bits: 0001 — 0100.
When each byte in the block P0[63:0] 110 equals A2* and each byte in the block P1[127:64] 100 equals A1*, the A1A2 boundary must be somewhere among the 136 bits formed by P1[63:0] 101 and P0[127:56] 112. One extra byte is included in this window because of the possibility that A1* and A2* will actually be shifted 7 bits from the A1 and A2 values. According to this embodiment of the present invention, the data in P1[127:64] 100 of the first data register 6 and the data in P0[63:0] 110 of the data input are compared by a comparator 8 (in FIG. 1 ) with A1* and A2*, respectively. When matches between all 8 bytes in P1[127:64] and A1* and all eight bytes in P0[63:0] and A2* are detected by the comparator, the A1A2 boundary has been detected.
FIG. 8 depicts an exemplary condition whereby the A1A2 boundary is detected according to the present invention. There is shown the situation where the A1A2 boundary 113 occurs among the first 64 bits of the 128-bit bus, which is to say, somewhere in P0[127: 64]. Referring to FIG. 8 , at time T=0, P0[127:0] 9 is composed entirely of A1* bytes. At time T=1, the subsequent clock cycle, the prior P0[127:0] values have been clocked into the first data register and are now represented by P1[127:0] 10. The A1A2 boundary 113 now occurs on the incoming data bus among the block P0[127:64] 111. Under these conditions, detection of the A1A2 boundary 113 occurs at time T=1 since P1[127:64] 100 all equal A1* and P0[63:0] 110 all equal A2*.
FIG. 9 illustrates how the method of the present invention detects the A1A2 boundary when it occurs among the last 64 bits in the data bus, P0[63:0] 110. At time T=0, P0[127:0] 9 is composed entirely of A1*. At time T=1, the subsequent clock cycle, P0[127:0] 9 contains the A1 A2 boundary in the last half of the register P0[63:0] 110. At time T=2, the prior values P0 have been clocked into the first data register and are represented by the values P1 [127:0] 10. At time T=2, the A1A2 boundary 113 occurs in the lower half of P1 or P1[63:0] 101. When this occurs the blocks of the upper half of P1, P1[127:64] 100 all equal A1* and the blocks of the lower half of P0, P0[63:0] 110 all equal A2*. The detection condition, in this case, occurs after 3 clock cycles rather than in 2, as in FIG. 8 .
Referring again to FIG. 1 , there is shown a comparator 8 receiving input from the incoming data bus 1 and DataReg 1 6 according to the method described above. The comparator compares the values of the lower half of the data input bus P0[63:0] 9 with the values of the upper half of DataReg 1 10 with eight bytes of A2* and eight bytes of A1* respectively. In one embodiment of the invention, the comparator is realized by an array of eight 128-bit comparators (not shown). Based on the values of A1* and A2*, the comparator 8 generates output control bits on a bit selection control bus, BitSelect[7:0]5. These control bits are used to shift the data in each byte, so that the data in each byte is either A1 or A2
In the method of the invention described above, it was demonstrated that the A1A2 boundary occurs among the 136 bits formed by P1[63:0] 2, and P0[127:56] 1. Since the comparison takes one clock cycle to generate the control signal on BitSelect[7:0] 5, one clock cycle delay is needed to compensate the clock difference between the BitSelect[7:0] and the data bus. In order to realign the data in accordance with the extent of the bit shift, the invention reconfigures P2[63:0] 3 and P1 [127:56] 4 to form a single realigned 128 bit long data. FIG. 3 shows in more detail how an exemplary embodiment of the present invention accomplishes the bit alignment of the data. In this example, a multiplexer array 14 includes 128 8-to-1 multiplexers and receives signals P2[63:0] 3 and P1[127:56] 4 at its inputs as shown. These values represent portions of the contents of DataReg 1 6 and DataReg 2 7 respectively. Together, P2[63:0] 3 and P1[127:56] 4 represent 136 sequential bits from the original serial data stream. Multiplexer array 14 receives the Bit Select[7:0] signal at its select input 11 . The control signal BitSelect[7:0] is used to shift the data in the new data bus 26 at the output of the multiplexer array 14 . In the exemplary embodiment described herein, the shift amount is from 0 to 7 bits, so that each byte in the 128 bit output data bus 26 is either A1 or A2, as shown in FIG. 4 . The multiplexer array 14 thus shifts the data P2[63:0] 3 and P1[127:56] 4 into a third 128-bit register 15 such that each 8-bit block of DataReg 3 15 contains only A1 or A2. The shifted data are stored in DataReg 3 15 as well as another sequential register, DataReg 4 16 . The values of these two registers are represented by F0[127:0] 12 and F1[127:0] 13, respectively. The bit alignment step according to this embodiment of the invention requires two clock cycles to complete. The values of DataReg 3 and DataReg 4 are shown in FIG. 4 .
The final alignment step in a method according to the present invention, byte shifts the data so that it is aligned along the A1A2 boundary. FIG. 5 shows Byte Select Logic 19 , which takes input F0[127:0] 12 from DataReg 3 15 . The data F0[127:0] 12, is examined to determine the location of the A1A2 boundary, in terms of number of bytes, from the edge of the bus. A 16-bit byte select control signal ByteSelect[15:0] 17 is generated onto bus 17 by the Byte Select Logic 19 . FIG. 5 also shows an array 20 of 128 16-to-1 multiplexers accepting both F0[127:0] 12 and F1[127:0] 13 as inputs. The multiplexer array 20 shifts the input data onto an output 128-bit register 21 in accordance with the ByteSelect[15:0] signal on bus 17 such that the output register 21 contains either A1 only or A2 only as is shown in FIG. 6 . This final alignment step requires 2 clock cycles to complete.
FIG. 10 is a block diagram of a SONET line card 200 that includes a framer implemented according to one embodiment of the present invention. Line card 200 includes an optical transceiver 202 that receives optical data from the fiber channel 204 and converts it to an electrical signal. The output of the optical transceiver 202 connects to an electrical transceiver 206 that performs the SER/DES functionality among others. The deserialized data at the output of electrical transceiver 206 is applied to a framer 208 . Framer 208 detects the A1A2 boundary and realigns the data as described above, and forwards it to a network processing unit NPU 210 . The NPU 210 interfaces with the switch fabric and performs various functions such as traffic control, protocol conversion and the like.
The SONET line card 200 using the framer 208 according to the present invention has a superior performance due to the speed and efficiency of the framer. The method of the instant invention as applied, for example, to the framer 210 of line card 200 , has at least two distinct advantages over prior art methods of aligning data along the A1A2 boundary. First, the method of the present invention as demonstrated in the exemplary embodiment above can accomplish the alignment in as few as five clock cycles. Second, the exemplary implementations of the present method presented herein are far more cost effective in terms of hardware requirements. Simulations have shown that the boundary detector according to the present invention can reduce the amount of circuitry down to as much as only 10% of the logic required by prior art implementations to perform the same function in a similar amount of time.
In conclusion, the present invention provides method and circuitry for detecting a boundary between two bytes of received data. In a specific implementation, the invention detects the A1A2 boundary of a SONET OC-N frame within a reduced number of clock cycles requiring significantly smaller circuitry to implement. While the above provides detailed description of specific embodiments, it is to be understood that various modifications, alternative implementations and equivalents are possible. The scope of the invention should therefore not be limited by the embodiments described above, and should instead by determined by the following claims and their full breadth of equivalents. | 4y
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RELATED APPLICATIONS
[0001] Not Applicable
FEDERALLY SPONSORED RESEARCH
[0002] Not Applicable
SEQUENCE LISTING
[0003] Not Applicable
BACKGROUND OF THE INVENTION
[0004] This application relates to bulletproof glass windows in vehicles and specifically a novel system to address the safety issues associated with bulletproof glass windows in vehicle accidents.
[0005] Bulletproof glass has been used for many years in vehicles such as armored bank vehicles for the transport of money. More recently, the use of bulletproof glass has increased in executive and government vehicles, particularly as an anti-terrorism measure. The occupants of these and other vehicles with such glass typically are not wearing helmets. If side curtain airbags are not provided in such vehicles, occupants of these vehicles can have significant head impacts with the bulletproof glass during motor vehicle accidents. Bulletproof side windows, typically with thicknesses in the range of 20 mm, present unforgiving impact surfaces in front oblique, rollover and side impacts. If occupant protection system designs do not provide sufficient lateral restraint to prevent injurious head impact with the bullet proof glass through use of side curtains or other design approaches, a passive impact protection system is desirable
[0006] A layer of energy absorbent material placed on the inboard side of a bulletproof window is a possible passive solution, but the choices for such a material are limited. To be acceptable, the material must be clear and not distort vision through the window. Known materials with the required energy absorbent properties and clarity tend to scratch easily and/or yellow or become opaque with age, and thus are not suitable for vehicle applications. What is needed is a passive restraint system that retains the durability and optical properties of window glass.
BRIEF SUMMARY OF THE INVENTION
[0007] The invention is a window system for a vehicle, including an outboard layer of bullet-proof glass, a stand-off layer inboard of the bullet-proof glass layer, and an inner layer of laminate safety glass inboard of the standoff-layer. The laminate safety glass is typically a plastic interlayer sandwiched between two glass layers.
[0008] In particular tested embodiments the plastic interlayer is PVB and the glass layer thickness is approximately 2 to 2.5 mm while the PVB interlayer thickness is between approximately 0.75 and 1.5 mm.
[0009] In other embodiments an energy absorbing material may be used around the perimeter of the stand-off region, providing the stand-off connection between the bullet proof glass and laminate glass layers, and/or the bullet-proof glass layer and the laminate safety glass layer may connected by energy-absorbing stand-offs. The system may further include exterior padding around the rim of the inboard side of the laminate safety glass layer, particularly desirable for the case where stiff stand-offs are employed. Typically it may also be desirable to include venting of the standoff layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The invention will be better understood by referring to the following figures.
[0011] FIG. 1 depicts the basic elements of the invention.
[0012] FIG. 2 shows the details of the laminate safety glass.
[0013] FIG. 3 is a Finite Element model of portions of the invention in operation
[0014] FIG. 4 shows an embodiment of the invention including energy absorbing material on the perimeter of the stand-off region
[0015] FIG. 5 shows an embodiment of the invention including energy absorbent stand-offs used to separate the two glass sections FIG. 6 depicts an embodiment with rim of energy absorbing material around the inboard layer.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The invention in it's broadest form, illustrated in FIG. 1 incorporates a layer of laminated safety glass 2 with a standoff region 3 inboard of the bulletproof glass layer 1 . Such a window system provides a more compliant and energy absorbing contact surface than bulletproof glass alone. If the gap between the bulletproof window and the laminated glass is sufficient, the energy absorbed by glass fracture and plastic deformation of the interlayer can significantly reduce the impact velocity of the head with the bulletproof glass or prevent contact altogether. In order to most conveniently be used in place of existing bullet-proof glass installations with little modification, it is envisioned that the laminate glass layer can be attached to the bullet-proof glass layer, as will be described below, either to an existing bulletproof layer, or as an assembly that can be used in place of a single bulletproof glass layer. For these cases, the inner safety layer is attached to the bulletproof glass layer across the stand-off region. It is also within the capability of one skilled in the art to envision a range of mounting frame possibilities for cases where the novel window system is designed in for a new or modified vehicle.
[0017] The laminate safety glass may be of a type already used in the automotive industry. Such window glass as shown in FIG. 2 , consists of two glass layers 4 and 6 which are formed into a sandwich about interlayer 5 commonly consisting of polyvinyl butyral (PVB). Such glass is typically constructed with the glass layers of thickness in the 2 mm range, and the PVB interlayer in the 0.75 mm range. Other materials and dimensions are possible as will be discussed below. It is known that the thinness of the glass layers provides a survivable head impact scenario, while the sandwich construction around the soft PVB interlayer provides overall structural strength along with relatively safe fracture characteristics. Such glass laminates are increasingly used in window and windshield design for vehicles, and are many times less dangerous in head impacts than 20 mm bulletproof glass, yet are perfectly acceptable optically and from a durability standpoint.
[0018] Since typical bullet proof glass is 20 mm thick, and common laminate safety glass is about 5 mm thick, an overall width for the system was chosen as about 75 mm, to avoid an impractically thick overall window system, indicating a desired standoff gap in the 50-65 mm range.
[0019] Using a variety of dimensions in the ranges above, Hybrid III dummy headform impacts were simulated using the LS-DYNA finite element program. A model of a Hybrid III headform developed by Livermore Software Technology Corp.(LSTC) was modified to improve correlation with head acceleration data from a 0.65 meter drop test of a Hybrid III headform on the top of the head. The model was also shown to meet peak acceleration requirements for a 2.7 m/s forehead impact for the headform validation portion of the FMVSS 201 occupant protection standard. A 19 mm-thick bulletproof window design was modeled, as well as various laminated glass panels with the same shape as the bulletproof window. The laminated glass was fixed inboard of the bulletproof window by perimeter standoffs of various heights within the above ranges dictating the gap between the laminated glass and the bulletproof window. The laminated window designs considered consisted of a typical interlayer of polyvinyl butyral (PVB) sandwiched between two identical plates of glass. The laminated glass finite element model was validated with force-deflection data from various quasi-static ring-on-ring bending tests. 15-mph lateral head impacts with various bulletproof window systems were simulated. The impacts were centered on the upper rear quadrant of the window, and the headform was tilted laterally 27 degrees from vertical. The strain-rate dependent PVB stress-strain properties were selected based on the strain rates seen in the laminated glass during failure in the 15-mph impacts. A depiction of the modeling is shown in FIG. 3 . For baseline comparison, a 15-mph impact with the unprotected bulletproof window was simulated that produced excessive head injury criterion (HIC) and peak head accelerations. For the range of system designs considered, it was found that a window spacing of about 50-65 mm was sufficient to keep HIC levels well below head injury thresholds for the 15-mph lateral impact modeled.
[0020] In order to keep the stand-off gap around 50-65 mm it was found that thicker than standard PVB interlayers are desirable. However sticking with the common glass layer thicknesses, in the 2 mm range, such laminate glass with thicker PVB interlayers is easily obtainable from existing sources. However thinner glass designs, alternate glass materials, thicker interlayers or interlayers of alternate materials are also possible. Glass alternatives include polycarbonates, glass-plastic, or plastic-composites. Alternative interlayer materials include Surlyn and Sentryglas-Plus. Use of alternative materials may allow for thinner laminates and/or thinner stand-off gaps. However, the commonly available Glass-PVB-Glass laminates in the dimensions tested produce acceptable results
[0021] Example results shown in the table below of selected laminated glass lay-ups and window spacings show that for PVB based formulations 50-57 mm gaps provide substantial improvements in head injury measures. In this table the HIC and peak acceleration values are normalized to the baseline unprotected bulletproof window values. A lay-up designation of 2.4/1.14/2.4 refers to a laminate with 1.14 mm of PVB sandwiched between two 2.4 mm plates of glass, and so on. Of those alternatives shown the 2.4/1.14/2.4 laminate with 57 mm spacing had performance almost 40 times better than the baseline. The same design also performed well for a 15-mph head impact located at the center of window (normalized peak acceleration and HIC of 0.312 and 0.073 respectively).
[0000]
50.8 mm gap
57.2 mm gap
Laminated
normalized
normalized
normalized
normalized
Glass Lay-up
peak acc
HIC
peak acc
HIC
2.1/1.52/2.1
0.340
0.081
0.115
0.025
2.4/1.14/2.4
0.310
0.067
0.232
0.041
[0022] Alternative stand-off arrangements are possible which may lead to either decreased overall stand-off width, or increased head impact protection. As shown in FIG. 4 , the standoff layer 3 could have an energy absorbent material 7 installed around the perimeter of the window and providing the stand-off connection between the bullet-proof layer and the laminate layer. It is also possible to employ a clear energy absorbing material and fill the stand-off region. In this case, the glass layers would protect against scratching and aging of the clear stand-off material. Or, as shown in FIG. 5 perimeter standoffs 8 could be used. The perimeter standoffs between the bulletproof glass and laminate layer could be constructed of energy absorbing material such as honeycomb to absorb impacts on the edge of the window. Alternatively, a variety of materials including metal, foam, rubber, composite, or plastic perimeter standoffs in various physical shapes could be employed. If a stiff stand-off is employed then as shown in FIG. 6 , exterior padding 9 around the perimeter in conjunction with the mounting assembly would be desirable to protect against impacts with the window edge. To prevent condensation in the chamber between the windows, the standoff should be provided with vent holes. The window chamber could also be incorporated into the vehicle defroster system. Costs for the improved performance are low compared to the costs for the bulletproof glass itself.
[0023] The novel bulletproof window system has been shown to provide up to a 40 times reduction in HIC levels over unprotected bulletproof glass for the 15-mph impacts simulated. The system design is modular and provides for insertion into the vehicle in a way that is compatible with current assembly techniques for insertion of bulletproof glass modules. Costs are similar to the original bullet proof glass costs since the material and module assembly costs are low. Improved performance can be provided with alternate interlayer materials. Other glass plastic, plastic, composite, plastic composite structures can be utilized for the inner layer. | 4y
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This Application is a divisional of parent application Ser. No. 10/741,769, filed Dec. 19, 2003. The parent application is herein incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] The invention concerns a microphone module for a hearing aid device with a microphone carrier to which a plurality of microphones are attached, as well as a method to produce such a microphone module.
[0003] For cosmetic reasons, there is with hearing aid devices the desire for an extensive miniaturization of the devices. Furthermore, the devices should be as cost-effective as possible. In order to be able to achieve these goals, high standards are employed in the production and test methods. The generation of individual modules that can be prefabricated before the assembly of the hearing aid device, and also can be individually tested first with regard to their functionality, represents a possibility for lowering the production costs of a hearing aid device.
[0004] Hearing aid devices are known with a plurality of microphones that are arranged on a common carrier, and thus form a microphone module that can be integrated as a structural unit in the housing of a hearing aid device, or can be connected with a housing of a hearing aid device. For example, German patent document DE 196 35 229 A1 shows such a hearing aid device.
[0005] Components are known from the electro-technical industry in which injection-molded plastic moldings are provided with three-dimensionally directed conductor traces. These components are designated as MID (Molded Interconnect Devices) and, for example, used as chip sockets or plug connections. The MID technology allows mechanical and electronic functions to be combined in a component. Mostly thermoplastic synthetics serve as a base material, however duroplasts [thermosetting materials] or elastomers are also used. The conductor traces are, as a rule, applied directly to the component via metallization. Further electronic components (resistors, capacitors, etc.) can subsequently by applied via gluing or soldering.
[0006] A modular hearing device with a microphone, a receiver, an amplifier and a battery is known from German patent document DE 691 11 668 T2, in which the microphone is incorporated into a microphone module, the receiver is incorporated into a receiver module, the amplifier is incorporated into an amplifier module, and the battery is incorporated into a battery module. The individual modules can be removably connected with one another via dovetail-shaped connections. The electrical connection of the individual modules ensues by way of a flexible circuit board that is soldered with contact points of the modules.
[0007] A hearing device is likewise known from U.S. Pat. No. 6,456,720, in which a plurality of components are electrically connected with one another via a flexible circuit board.
[0008] As to the formation of conductor traces, various methods for metallization and structuring of the synthetic carrier are known, in particular from MID technology, of which the common ones are be briefly mentioned:
[0009] In heat stamping, the synthetic substrate is metallized and structured in one step. With a stamping die on which the positive conductor pattern is applied, a copper stamping foil with an intermediate bonding layer is pressed under pressure and the addition of heat onto the synthetic substrate. The substrate is melted on the surface via the heating effect. The conductor traces are cropped from the copper foil and connected with the substrate.
[0010] In metal-backed injection, a structured conductive pattern develops on a foil via screen or pad printing of a primer. During a conditioning process under temperature, the primer undergoes a chemical connection with the substrate surface and provides for a good bond strength. In this process, the foil is simultaneously formed. The foil is subsequently placed in an injection molding machine and back-injected. After the back-injection, the conductor traces are galvanically strengthened and refined.
[0011] In the two-component injection molding method, the structure of the conductive pattern is produced with a first injection molding made of metallizable synthetic that serves as a substrate for the chemical metallization. Depending on the synthetic, the surface must be treated again after the first injection molding. The small injection is newly inserted/loaded into a mold and extrusion-coated with non-metallizable synthetic. The free remaining conductor traces are subsequently chemically metallized and enriched.
[0012] In the masking method, the metallization of the synthetic carrier ensues via chemical coating. A synthetic injection molding part serves as a substrate in which the surface is initially prepared via corrosion or, respectively, etching for the next step of the process. The metallization subsequently ensues. A photoresist is applied for structuring and exposed with UV light via a three-dimensional mask. After development of the photoresist, the uncovered metal layer is galvanically strengthened and coated with an etching mask. After removal of the photoresist, the remaining metal is etched away and the surface is subsequently enriched.
[0013] In contrast to the masking method, in direct laser structuring the etching resist is directly structured with the laser. At the points at which the etching resist was removed by the laser, the metal is etched away. The surface is subsequently enriched.
[0014] In the LPKF laser direct structuring method, which is named after the company LPKF, a synthetic part is first injection molded. The transfer of the structure pattern subsequently ensues with a writing or imaging laser system. The subsequent metallization ensues in a chemically reductive bath.
SUMMARY OF THE INVENTION
[0015] It is the object of the present invention to simplify the production of a hearing aid device with a plurality of microphones.
[0016] This object is achieved via a microphone module for a hearing aid device with a microphone carrier on which a plurality of microphones are attached, where the microphone carrier is fashioned as a solid plastic molding with three-dimensionally directed conductor traces for electrical connection of the microphones.
[0017] Furthermore, the object is achieved via a method for production of a microphone module for a hearing aid device, with the following steps:
[0018] a) generation of a microphone carrier in the form of a solid plastic molding, from a synthetic material,
[0019] b) application of three-dimensionally directed conductor traces on the synthetic material,
[0020] c) attachment of microphones on the carrier, and production of electrical connections between microphone contacts and the conductor traces.
[0021] A microphone carrier is generated first in the production of a microphone module according to the invention. In a preferred embodiment, this is designed such that all microphones present in a hearing aid device can be attached to it. In order to allow for the acoustic requirements for the microphones as well as the crowded space proportions in the housing of a hearing aid device, inevitably an uneven shaping normally results for the microphone carrier.
[0022] The microphone module according to the invention assumes not only the function of attaching the microphones, but additionally and advantageously serves at least in part for electrically connecting the microphones among one another and with an electronic signal processing unit in the hearing aid device. In order to enable an almost arbitrary shaping of the microphone carrier, the carrier is preferably constructed from a thermoplastic, duroplastic or elastomer synthetic material. According to an embodiment of the invention, direct conductor traces for the electrical connection of the microphones are also applied to this synthetic material. Alternatively, the conductor traces can also be wholly or partially enclosed by the synthetic material of the microphone carrier.
[0023] The formation of the microphone carrier in MID technology enables both an almost arbitrary shaping of the microphone carrier and the generation of three-dimensionally directed conductor traces on the microphone carrier or, respectively, in the microphone carrier for electrical connection of the microphones. This has a plurality of advantages according to various embodiments of the invention:
[0024] Via the microphone carrier, the microphones may be combined in a simple and cost-effective manner into a modular structural group—a microphone module. This can be directly soldered to the microphone carrier to attach the microphones. The electrical connection is thus also simultaneously produced. Since the microphones are already electrically connected with one another via the conductive pattern applied to the microphone carrier, two conductors (positive pole, ground conductor) are sufficient for a voltage supply of all microphones of the hearing aid device, for which, until now, two conductors for each microphone have been necessary. Furthermore, the microphones can already be tuned to one another and tested with regard to their transmission behavior after the assembly of the module, before their installation and integration into a hearing aid device.
[0025] A further advantage is that, in a simple manner, a plurality of different hearing device variants can be generated via different microphone modules that, for example, can be equipped with two, three or more microphones. Different functionalities of the resulting hearing device can result, and thus different hearing device variants, depending on with which type of microphone module (for example, with two, three or four microphones) a hearing device is equipped.
[0026] Furthermore, embodiments of the invention offers the advantage that the microphone carrier can be equipped with further electronic components in addition to the microphones. If the microphones are omnidirectional microphones, an electrical circuiting of the microphones is necessary for assembly of a directional microphone system. The microphone signal of at least one microphone must be delayed and inverted and added to the microphone signal of a further microphone. For this, necessary components (for example, delay elements and inverters) are advantageously directly placed on the microphone carrier, such that the microphone module already generates a distinct directional characteristic. The microphone carrier may also comprise the conductor traces for electrical connection of these components. Moreover, in modern hearing devices, at least one digital signal processing ensues. The embodiments of the invention also enable the attachment of A/D converters on the microphone carrier, such that digital signals are already supplied by the microphone module.
[0027] The electrical contacts of a microphone module according to embodiments of the invention can be realized via stranded conductors, flexible circuit boards or plug connectors. Furthermore, it is possible that the microphone module itself serves as a plug connector.
[0028] To generate a directional microphone system from a plurality of omnidirectional microphones electrically circuited with one another, it is necessary that the microphones are very precisely tuned to one another with regard to their amplitudes and phase transmission behavior. The embodiments of the invention also offer advantages in that components (for example, resistors and capacitors) necessary for microphone tuning may be directly arranged with one another on the microphone carrier. The microphones can thus advantageously already be tuned (“matched”) before the installation in the hearing aid device. A directional microphone system can thus be produced, calibrated and tested as a separate physical unit. Last, but not least, advantages also result in the event of repairs of a hearing device. Instead of individually replacing defective microphones, the complete microphone module may now be exchanged, foregoing the calibration of a replaced microphone with microphones remaining in the hearing device.
[0029] Via the invention, it is furthermore possible to shrink the microphone modules such that they fit into hearing aid devices of smaller design, for example behind-the-ear hearing aid devices. Additionally, this achievable reduction of the number of the connection wires for electrical connection of the microphones (for example, from nine to five connection wires in a microphone module with three microphones), via the softer arrangement of the microphone module connected therewith, brings an acoustic advantage.
[0030] A further embodiment of the invention provides an oscillation-damped arrangement of a microphone module according to the invention in a hearing aid device. The oscillation-damped arrangement can ensue both via the microphones and via the microphone carrier. For example, for this the microphones and also the socket of the microphone inlet may be coated with elastic, oscillation-damping material, for example, rubber jackets. An oscillation-damping arrangement of the individual microphones in the housing of a hearing aid device is thus no longer necessary. Damping elements made of elastic, oscillation-damping materials are also advantageously located between the microphone carrier and acceptances for mounting the microphone carrier in the hearing device housing. The entire microphone module may thus be largely decoupled from the housing of the hearing aid device via oscillation technology.
[0031] The microphone module according to the invention can be used in all common hearing device designs, for example, in in-the-ear hearing aid devices (IdOs), behind-the-ear hearing aid devices (HdOs), pocket hearing aid devices, and so forth.
DESCRIPTION OF THE DRAWINGS
[0032] Further advantages and details of the invention emerge from the subsequent specification of exemplary embodiments of the invention and the drawings.
[0033] FIG. 1 is a side view pictorial diagram of a microphone carrier;
[0034] FIG. 2 is a top view pictorial diagram of a microphone carrier;
[0035] FIG. 3 is a bottom view pictorial diagram of a microphone carrier;
[0036] FIG. 4 is a side view pictorial diagram of a microphone carrier equipped with three microphones;
[0037] FIG. 5 is a bottom view pictorial diagram of a microphone carrier equipped with three microphones;
[0038] FIG. 6 is an isometric view pictorial diagram of a partition of a behind-the-ear hearing aid device in which a microphone module according to the invention is used;
[0039] FIG. 7 is an isometric view pictorial diagram of the partition as well as the microphone module according to FIG. 6 , where the microphones are provided with jackets made of elastic material for oscillation-damping arrangement; and
[0040] FIG. 8 is a side view pictorial diagram of a microphone module that comprises electrical components for circuiting the microphones and signal processing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] FIG. 1 shows a microphone carrier 1 fashioned as a plastic injection-molded part, in side view. To form a microphone module, three microphones can be attached to the microphone carrier 1 in sections 1 A, 1 B and 1 C of the microphone carrier 1 . Two of the microphones are spatially separated by a web 1 D of the microphone carrier 1 .
[0042] In the production of the microphone carrier according to an embodiment of the invention, in a first method step, a plastic injection-molded part is produced in the shape visible from FIG. 1 . To generate conductor traces on the plastic injection-molded part, the method steps add metallization and structuring. For attachment and electrical contacting, a plurality of microphones are subsequently soldered onto the thusly produced microphone carrier 1 .
[0043] FIG. 2 shows the microphone carrier 1 from above. From this view, the conductor traces 2 - 6 directly applied on the microphone carrier 1 for electrical contacting of the microphones are visible. It is clear that both conductor traces 2 and 3 for the voltage supply of the microphones respectively comprise contacts for contacting all three microphones. Furthermore, the microphone carrier 1 comprises a separate signal line/conductor for each microphone. In the assembly of the microphone module, the microphone arranged in the partition 1 A of the microphone carrier 1 visible from FIG. 1 is soldered with its microphone contacts to the contact points 2 C, 3 C and 6 A for attachment and for electrical connection. The attachment and contacting of both other microphones ensues on the bottom of the microphone carrier 1 . The conductor traces 2 - 5 are therefore provided with feed-through holes 2 A, 2 B, 3 A, 3 B, 4 A and 5 A, through which the conductor traces are passed for further continuation on the bottom of the microphone carrier 1 .
[0044] Altogether, the electrical connection of the three microphones ensues via the five conductor traces 2 - 6 . To connect the microphone module with an amplifier (not shown), only five (instead of the normal nine) connection conductors are thus necessary. The microphone module thereby contributes to a lowering of the production costs of a hearing aid device.
[0045] The bottom of the microphone carrier 1 is visible from FIG. 3 . The microphone carrier 1 in the exemplary embodiment also comprises conductor traces on its bottom, namely the conductor traces 7 and 10 that are continuations of the conductor trace 2 , the conductor traces 8 and 11 that are continuations of the conductor trace 3 , the conductor trace 9 that is a continuation of the conductor trace 4 , and the conductor trace 12 that is a continuation of the conductor trace 5 . The continuations of the conductor traces may be (as is specified in FIG. 2 ) formed by way of the feed-throughs 2 A, 2 B, 3 A, 3 B, 4 A and 5 A for continuation of the respective conductor trace on the opposite side of the microphone carrier 1 . The conductor trace sections on the bottom of the microphone carrier 1 respectively end at a contact point 2 D, 3 D, 4 B (for one microphone) or, respectively, 2 E, 3 E, 5 B (for a further microphone). The contact points for respectively one microphone may be separated from one another by the web 1 D. Both microphones on the bottom of the microphone carrier 1 may be also soldered with the contact points 2 D, 3 D 4 B, 2 E, 3 E and 5 B for attachment as well as for electrical connection.
[0046] FIG. 4 shows the microphone carrier 1 with the three microphones 13 , 14 and 15 attached on it. Each microphone comprises three microphone contacts, of which respectively only the front microphone contact 13 A, 14 A or, respectively, 15 A is visible in FIG. 4 . The microphone 13 is soldered to its microphone contacts at the contact points 2 C, 3 C and 6 A (compare FIG. 2 ) on the top of the microphone carrier; the two microphones 14 and 15 with their microphone contacts are soldered to the contact points 2 D, 3 D, 4 B or, respectively, 2 E, 3 E and 4 B on respectively one side of the web 1 D (compare FIG. 3 ). Furthermore, five connection cables 16 - 20 are visible for electrical connection of the microphone module with an amplifier unit (not shown).
[0047] FIG. 5 shows the microphone module with the microphone carrier 1 and the three microphones 13 , 14 and 15 from below. From this view, three sound inlets (fashioned as sockets 13 D, 14 D and 15 D) of the microphones 13 - 15 are visible. Furthermore, from this view, at the microphones 14 and 15 their microphone contacts 14 A, 14 B, 14 C or, respectively, 15 A, 15 B, 15 C are recognizable. These are soldered to the contact points 2 E, 3 E, 5 B or, respectively, 2 D, 3 D, 4 B on opposite sides of the web 1 D. In addition, FIG. 5 also shows the five connection cables 16 - 20 for electrical connection of the microphone module with an amplifier unit (not shown).
[0048] FIG. 6 shows a section of a behind-the-ear hearing aid device 21 in which a microphone module according to the invention is located. In FIG. 6 , the microphone module is not fully located in its end position in the installed state, and therefore partially protrudes over the housing of the hearing aid device 21 . On the top of the microphone carrier 1 , respectively one test port 23 A- 23 E for contacting a test device is located in the region of the connection cable 16 - 20 on the conductor traces. The correct function of the microphone module can, by this, be tested before the installation in the hearing aid device. Defective microphone modules can thus be eliminated early in the production process of the hearing aid device. Furthermore, FIG. 6 shows a sound aperture opening 22 in an uncropped shown region of the housing of the hearing aid device 21 . In the installed microphone module, the socket 13 D of the microphone 13 (not visible from FIG. 6 ; compare FIG. 5 ) protrudes in this sound aperture opening. The sockets 14 D, 15 D of the remaining microphones likewise protrude in corresponding further housing openings of the hearing aid device 21 (not shown). The microphone module is thereby fixed in the hearing aid device 21 in a simple manner.
[0049] FIG. 7 shows the section of the hearing aid device 21 (corresponding to FIG. 6 ) with the microphone module according to an embodiment of the invention in detail. However, in contrast to FIG. 6 , in the embodiment according to FIG. 7 the microphones as well as the sockets are encased in jackets 24 , 25 and 26 made of elastic, oscillation-damping material, that to some extent even enclose the microphone carrier. The attachment of the microphone module in the hearing aid device 21 and the oscillation-technical decoupling of the microphone module from the housing of the hearing aid device 21 is thereby improved. Moreover, damping elements (not shown) can likewise be located at further connection points of the microphone carrier 1 with the housing of the hearing aid device 21 .
[0050] FIG. 8 shows a development of the invention. A plurality of omnidirectional microphones 13 ′, 14 ′ and 15 ′ are thereby arranged on a common microphone carrier 1 ′ and electrically circuited with one another to form a directional microphone system. In this embodiment, the electronic components necessary for electrical circuiting (for example, delaying elements and inverters) are advantageously likewise directly mounted on the microphone carrier 1 ′. The components are comprised in the physical unit 27 ′ that is arranged over the microphone 15 ′ on the microphone carrier 1 ′ in the exemplary embodiment.
[0051] The physical unit 27 ′ can be implemented as an integrated circuit, and thus as an electronic component with it own housing. However, a plurality of electrical components can likewise also be placed in a distributed manner on the microphone carrier 1 ′. The conductor traces for electrical connection of the component 27 ′ are also advantageously located directly on the microphone carrier. A directional microphone system can thus by realized in a simple manner, in that electronic components necessary to fashion the directional microphone system are also comprised by the microphone module. The microphones 13 ′, 14 ′, 15 ′ of the microphone module can then already be calibrated before the microphone module is used in a hearing aid device. The calibration with regard to the transmission behavior of the microphones 13 ′, 14 ′, 15 ′ is particularly necessary when a directional microphone system of higher order should be formed via electrical circuiting.
[0052] Furthermore, the microphone carrier 1 ′ can be provided with further electrical components, where the functionality of the microphone module is, for example, expanded to the effect that a signal preamplification and A/D conversion of the microphone signals also ensues. These components can also be comprised by a single integrated circuit on the microphone carrier. However, a plurality of electrical components can also be mounted on the microphone carrier 1 ′. Digital, and thus largely interference-insensitive signals are thus already supplied from the microphone module to the signal outputs.
[0053] For the purposes of promoting an understanding of the principles of the invention, reference has been made to the preferred embodiments illustrated in the drawings, and specific language has been used to describe these embodiments. However, no limitation of the scope of the invention is intended by this specific language, and the invention should be construed to encompass all embodiments that would normally occur to one of ordinary skill in the art. The particular implementations shown and described herein are illustrative examples of the invention and are not intended to otherwise limit the scope of the invention in any way. For the sake of brevity, conventional electronics and other functional aspects of the systems (and components of the individual operating components of the systems) may not be described in detail. Furthermore, the connecting lines, or connectors shown in the various figures presented are intended to represent exemplary functional relationships and/or physical or logical couplings between the various elements. It should be noted that many alternative or additional functional relationships, physical connections or logical connections may be present in a practical device. Moreover, no item or component is essential to the practice of the invention unless the element is specifically described as “essential” or “critical”. Numerous modifications and adaptations will be readily apparent to those skilled in this art without departing from the spirit and scope of the present invention.
REFERENCE LIST
[0000]
1 microphone carrier
1 A, 1 B, 1 C sections of the microphone carrier
1 D web
2 - 12 conductor traces
2 A, 3 A, 4 A; feed-throughs
2 B, 3 B, 5 A
2 C, 3 C, 6 A; contact points
2 D, 3 D, 4 B;
2 E, 3 E, 5 B
13 , 14 , 15 ; microphones
13 ′, 14 ′, 15 ′
13 A; microphone contacts
14 A, 14 B, 14 C;
15 A, 15 B, 15 C
13 D, 14 D, 15 D sockets
16 - 20 connection cable
21 hearing aid device
22 sound aperture opening
23 A, 23 B, 23 C, test ports
23 D, 23 E
24 , 25 , 26 jackets
27 ′ electrical component | 4y
|
TECHNICAL FIELD
The field of this invention relates to faucets and more particularly to faucets with an adjustable delivery spout and a single operating lever.
BACKGROUND OF THE DISCLOSURE
Faucets with swivel spouts may easily confuse a user for determining which direction to move the operating lever in order to adjust flow rate of water and to adjust temperature mix. Indeed, in the use of normal faucets equipped with delivery spouts fixed on the faucet body, the user usually orients himself and moves the lever relative to the delivery spout, which is usually directed forward to the user and extending over the working basin or sink. The user is thus led to follow the same criterion with a faucet equipped with an adjustable delivery spout. In this case the user obtains a completely different result when the orientation of the delivery spout is substantially moved in relation to the body of the faucet. The user must orient himself with a forward direction which under certain circumstances may be difficult to precisely observe. The user no longer orients himself with the spout because the mixing cartridge or mixing valve is traditionally installed in a recess or cavity in the fixed body of the faucet. As a result, the position of the operating lever to obtain delivery of a required flow rate of water mixed to a desired temperature must be in reference to a fixed direction with the fixed body. This direction is easily observable when the spout is in a centered forward position. However, when the spout is moved, the direction is less clear to the user. Furthermore, the position of the lever has no relation to the actual orientation of the delivery spout that is adjustable in relation to the fixed body of the valve.
The inconvenience of orienting with the fixed body and not the spout becomes particularly pronounced when the operating lever is of the type commonly referred to as a “joystick” type. In a joystick type faucet, the lever is subject to movement in a first direction to regulate the flow rate from a full flow condition down to a shut-off position and in a second direction which is orthogonal to the first direction to regulate the mixing ratio or temperature mix. The shut-off position is singular, i.e. the faucet is shut off only when the lever is moved to a central position over the fixed delivery spout. When the spout is adjusted to a position other than a central position, the user may experience difficulty in shutting off the flow, or may think he has shut off the flow while in fact this has not happened completely and the faucet will drip. This situation occurs more commonly when the spout is only slightly rotating from its central position, and a person assumes that the spout is centered and moves the lever to align with the spout.
What is needed is therefore to resolve the problem explained above so that the user of a faucet with an adjustable spout can correctly orient the lever to correctly adjust flow rate and temperature and be assured that the faucet is completely shut off. This assurance should be equally ascertained for all rotated directions of the adjustable spout.
SUMMARY OF THE DISCLOSURE
In accordance with one aspect of the invention, the recess or cavity for installation of the mixing cartridge on the faucet is in a component of the faucet mounted for rotation with the delivery spout, that in turn is adjustable in relation to the fixed body of the faucet. Because of this feature, the cartridge valve installed in the faucet rotates together with the delivery spout. When the orientation of the spout in relation to the fixed body of the faucet is altered, the orientation for correct movement of the operating lever also rotates correspondingly. The user can then operate the lever by adopting the same criteria he is accustomed to adopt in operating faucets with fixed delivery spouts, and this is translated into greater ease of operation.
Preferably the orientation of the mixing cartridge is pre-determined by a recess in the same component of the faucet which integrally forms its adjustable spout.
Preferably the faucet employs a mixing cartridge of the open type, offering lateral delivery openings, and the component in which the orientation for the mixing cartridge is pre-determined offers a peripheral area into which the delivery openings of the mixing cartridge open and which communicate directly with an internal passage of the delivery spout.
Preferably, for the purpose of ensuring proper supply to the mixing cartridge in any position of the delivery spout of the valve, the component in which the orientation of the mixing cartridge is predetermined offers a two-way rotating hydraulic coupling in relation to the fixed body of the faucet that in turn is connected to the supply pipes. Preferably this rotating hydraulic coupling involves a central passage connected to one of the supply pipes and a peripheral chamber at least partially ring-shaped, connected to the other supply pipe.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference now is made to the accompanying drawings in which:
FIG. 1 illustrates an external view of a form of embodiment of the faucet whose fixed body offers an adjustable delivery spout;
FIG. 2 is a top plan view of a faucet with an adjustable spout in accordance with the prior art illustrating how the spout when rotated becomes aslant with the orientation for operation of the operating lever;
FIG. 3 is a top plan view of the faucet shown in FIG. 1 illustrating the corresponding orientation for operation of the operating lever when the spout is rotationally adjusted between two positions;
FIG. 4 shows a segmented view of the valve as in FIG. 1, illustrating the internal components of this invention;
FIG. 5 shows the fixed body in FIG. 4;
FIG. 6 shows the adjustable component and spout mounting the mixing cartridge in FIG. 4;
FIG. 7 illustrates a side elevational view of another embodiment of a faucet in accordance with the invention; and
FIG. 8 is a segmented view of another embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, a faucet 29 has a fixed body 1 on which is mounted a rotating component 11 which forms a delivery spout 14 . A cover 26 holds a mixing cartridge 21 in place inside the faucet 29 . The cartridge is equipped with an operating lever 25 . The lever 25 is shown in the form of an erect straight pole and is of the type commonly referred to as a “joystick”. As noted, this operating lever 25 can be moved in a first direction (in the plane of the drawing as shown in FIG. 1) to adjust the flow rate of mixed water between full flow and a shut-off position. In the drawings the control lever 25 is represented in the shut-off position. The operating lever can also be moved in a direction orthogonal to the first direction (perpendicular to the plane of the drawing) to regulate the mixing ratio between cold and hot water.
In order for one to use the faucet properly, the user must know these directions of movement of the operating lever 25 . The delivery spout 14 is the only part of the faucet that has a prominent extension for indicating a well-defined direction. Because many faucets have fixed delivery spouts, the user habitually takes the direction of the delivery spout 14 as reference for correct operation of the control lever 25 . The operator is thus instinctively or intuitively led to adopt the same criterion or orientation even when the delivery spout is adjustable. However, in this case, known faucets with adjustable spouts may mislead the user as shown in FIG. 2 . The direction shown by the delivery spout 14 varies, as shown by the difference between a first centered position shown in phantom and a second rotated position. It is noted that the directions of movement of the lever 25 of the mixing cartridge, which is installed in a cavity or recess on the fixed body 1 of the faucet always remain unchanged and therefore has a variable relationship with the direction of the delivery spout 14 . As shown in FIG. 2, when the spout is rotated, the two orthogonal axes of motion 31 , 33 of the control lever 25 become aslant with respect to the spout 14 , and the lever 25 become s aslant with respect to the spout 14 when in the shut-off position.
In the invention, as is shown in FIG. 4, the mixing cartridge 21 from which the control lever 25 extends is in fact installed in a cavity or recess 35 of a rotating component 11 . The component 11 has the delivery spout 14 integrally formed therewith. The cartridge is retained in the component 11 by the cover 26 which, in this case is secured to the rotating component 11 . The longitudinal axis of the cartridge 21 is aligned with the axis of rotation of the spout 14 . Consequently, when the delivery spout 14 is adjusted in relation to the fixed body 1 , the rotating component 11 also turns, and the mixing cartridge 21 also rotates together with these parts, as illustrated in FIG. 3 . Therefore, the two axes of movement 31 , 33 of the operating lever 25 rotate in relation to the fixed body 1 , and remain constant or fixed with respect to the spout 14 . This fixed relation to the spout is shown in FIG. 3 by the comparison of the two sets of orthogonal axis 31 , 33 . One set is in phantom corresponding to the phantom spout position and the second set is solid corresponding to the rotated solid spout position. The lever 25 also retains its own orientation with respect to the delivery spout 14 . If the spout 14 is rotated, the lever 25 moves with the spout as illustrated in FIG. 3 . Thus, the user may refer to the direction of the delivery spout 14 to determine the directions in which he must move the operating lever 25 to adjust the flow rate of water and the desired temperature. This is what he is accustomed to do when using faucets with fixed delivery spouts. Furthermore, the operating lever 25 is always aligned over the spout 14 when in the shut-off position.
Reference now is made to FIGS. 4 and 6 to illustrate the recess or cavity 35 in the rotating component 11 . The cavity 35 that receives the mixing cartridge 21 offers a peripheral area or gap 12 , into which open out the lateral delivery openings 22 of the cartridge 21 (which is of the open type). The gap 12 communicates directly with passage 13 of the delivery spout 14 .
It is apparent that, in modifications, the delivery spout 14 can be a component that is structurally separate from the rotating component 11 and is appropriately connected to component 11 . In addition, the recess or cavity 35 that receives the mixing cartridge 21 may not be directly formed in the rotating component 11 but in a component structurally separate and in turn installed in rotating component
In order to ensure proper supply to the mixing cartridge 21 , a two-way hydraulic connection is between the rotating component 11 and the fixed body 1 of the faucet. This connection can be better seen with reference to FIGS. 5 and 6. The rotating component 11 offers a projecting part 15 which offers a central opening 16 and a peripheral ring chamber 18 . The central opening 16 communicates, via a channel 17 , with a first inlet 23 to the cartridge 21 , while the peripheral ring chamber 18 communicates, via a channel 19 , with the second inlet 24 of the cartridge 21 .
The fixed body 1 itself of the faucet has a cavity 2 intended to rotatably receive the projecting part 15 of the rotating component 11 . Fixed body 1 has a central opening 3 which communicates with a connection 4 for a first supply pipe (not shown), and a peripheral ring chamber 5 which communicates via a passage 6 with a connection 7 for the second supply pipe (not shown). The parts described are designed so that, when the rotating component 11 is mounted on the fixed body 1 of the faucet, the central openings 3 and 16 can communicate with each other and chambers 5 and 18 communicate with each other. The respective passages are watertight due to seal 8 in opening 3 and ring seals 9 about ring chamber 18 . In this way the supply of cold and hot water to the cartridge 21 is ensured for every rotated position of the delivery spout 14 .
The projecting part 15 of the rotating component 11 also offers a peripheral ring groove 20 into which receives a retaining screw 10 screwed through the fixed body 1 . The screw 10 mechanically couples the rotating component 11 in place axially without inhibiting its rotation. The ring groove 20 can be an incomplete arc for the purpose of limiting the field of rotation allowed to the rotating component 11 and to the delivery spout 14 . Correspondingly the peripheral ring chambers 5 and 18 may be incomplete arcs along the circumference.
It is understood that in other forms of embodiment, the two-way rotating hydraulic connection between the fixed body 1 and the rotating component 11 can be structured differently, as is known in the prior art for these hydraulic connections. Also, multiple screws 20 may be received circumferentially about parts of the groove 20 to rotationally secure component 11 to the fixed body 1 .
Moreover, the control lever 25 is represented as a straight leg or pole but for certain applications it can be molded and shaped and used with the same internal valve mechanism. For example, the lever 25 may be contoured towards the delivery spout as is found in many known faucets.
The central shut-off position of the “joystick” ever 25 always corresponds to the direction of the adjustable spout 14 . This shut-off position is selected so that the user is always certain of reaching complete shut-off by moving the lever towards the delivery spout. However, for certain applications, the shut-off position may be reversed, i.e. lifted up in opposition or away from spout 14 or may even be set at a 90 degree offset position for certain applications. In all situations, the shut-off position is permanently set with respect to the spout. Secondly, the orientation of operation is also set with respect to the spout. The application of the invention therefore offers two major advantages for valves with “joystick” operating lever.
The invention can naturally be applied also to faucets of different shapes and different valve operations from that represented in FIGS. 2 to 6 . For example, FIG. 7 illustrates how the invention can be applied to a faucet on whose fixed body 1 is not of the so called “joystick” type. FIG. 7 illustrates a valve that is subject to rotation about axis B—B for temperature adjustment and movement about an orthogonal axis for flow adjustment. The handle may be aesthetically contoured for ease of operation about axis B—B for temperature control and for movement about the orthogonal axis for flow control. Moreover, in this example, the cartridge is mounted, in relation to the rotating component 11 , on the axis B—B which forms an angle with the axis of rotation A—A of the adjustable spout. Both axis A—A and B—B are in the plane of the drawings and aligned with the center vertical plane of the spout 14 . These arrangements can turn out to be preferable in some cases, especially in view of certain shapes of the control lever. In this type of faucet, there are many shut-off positions along an arc where the lever is in a down position away from axis B—B. As such, the lever need not be aligned with the spout to completely shut off the faucet. The user still needs an orientation to correctly set the temperature. Usually, the mix position is in the center of the adjustable field of operation and is centered with a fixed spout. In the present invention the center of the adjustable field is oriented with the adjustable spout and rotated therewith. The application of the invention provides the orientation for the correct operation of the control lever 25 .
FIG. 8 illustrates another embodiment of invention incorporating a ball valve that is not a cartridge format. In this embodiment, the rotating component 11 has a recess 41 shaped to receive valve seals 43 in the downstream ends of passages 17 and 19 that seat flushly against ball valve 44 . Ball valve 44 has a control stem 46 passing through cap 26 and is affixed to operating lever 25 . The ball valve 44 is not in a cartridge format but is merely installed in appropriately shaped recess 41 in component 11 . Nevertheless, as spout 14 is adjusted, component 11 is also rotated and carries with it the ball valve 44 and operating lever 25 such that the operation of lever 25 is always oriented with respect to the spout 14 . The actual internal drive components of the ball valve 44 are well known in the prior art and do not form part of this invention.
It must be understood that the invention is not limited to the form of embodiments described and illustrated as examples. Other variations and modifications are possible without departing from the scope and spirit of the present invention as defined by the appended claims. | 4y
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This is a divisional of application Ser. No. 07/387,664, filed Jul. 31, 1989, now U.S. Pat. No. 5,046,617.
BACKGROUND OF THE INVENTION
The invention relates to an apparatus for the feeding of stacks of blanks for the production of packs, especially of hinge-lid packs for cigarettes, to a packaging machine.
The increasing performance of packaging machines presents problems in supplying them with sufficient quantities of packaging material. This applies, above all, to the production of packs from punches blanks prefabricated outside the packaging machine. An example of this is hinge-lid packs for cigarettes which are made from blanks of thin cardboard produced by punching in a paper factory. The blanks arrive at the packaging machine in the form of a blank stack.
The packaging machine is conventionally equipped with a blank magazine of relatively low capacity. A certain stock of stacked blanks can be introduced into this.
The subject of the invention is the transport of blanks produced and stacked outside the packaging installation, especially in a paper factory, to the packaging machine.
SUMMARY OF THE INVENTION
The object on which the invention is based is to provide measures for an efficient transport of relatively large quantities of stacked blanks from the production shop to the processing installation, especially to the packaging machine, at the same time involving only a relatively small amount of manual labour.
To achieve this object, the apparatus according to the invention is characterized by containers (cassettes), open at least on the top side, for receiving several blank stacks which are arranged next to one another and which are held laterally by vertical walls or wall parts of the container, especially by webs.
According to a further feature of the invention, the containers or cassettes are designed so that several empty cassettes can be nested in one another, with the result that they can be transported simply and in a space-saving way as empty stock.
The invention is based on the idea of packaging the blanks or blank stacks in re-usable containers at the place of manufacture and of transporting them in these to the place of use. After emptying, units consisting of several cassettes nested in one another (stack block) are transported back to the blank production plant. The cassettes can be brought to the packaging machine and emptied there. Alternatively, the cassettes can be transported in the region of the packaging machine and emptied directly in the region of the blank magazine of the packaging machine.
The cassettes are constructed in such a way that they consist of a load-bearing bottom wall and of a multiplicity of partition wall parts arranged on this, with a lateral limitation of chambers which each receive a blank stack. The partition wall parts are so designed and arranged that, in conjunction with orifices and additional orifices in the bottom wall, they make it possible to plug empty cassettes together. The cassettes nested or stacked in one another according to the invention constitute a space-saving unit (stack block) for the return transport to the production loading point.
Furthermore, the cassettes are designed so that (filled with blank stacks) they are stackable, for example for transport on pallets. Moreover, they are suitable for conveyance within a packaging installation by means of overhead conveyors.
Further features of the invention relate to the design of the cassettes and to apparatuses for the handling or transport of these.
An exemplary embodiment of the inventions explained in detail below by means of the drawings. In these:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a front view of a cassette for receiving blank stacks,
FIG. 2 shows a side view of the cassette according to FIG. 1, offset at 90°,
FIG. 3 shows a plan view of the cassette according to FIGS. 1 and 2, with blanks in individual chambers,
FIG. 4 shows a front view of cassettes stacked above one another with blank stacks,
FIG. 5 shows a bottom view of a cassette,
FIG. 6 shows a cassette on a fixture of a conveyor,
FIG. 7 shows a side view of FIG. 6, offset at 90°,
FIG. 8 shows a front view of a phase of the internesting of several (four) cassettes,
FIG. 9 shows a representation according to FIG. 8 in a side view offset at 90°,
FIG. 10 shows internested cassettes stacked above one another,
FIG. 11 shows a representation of FIG. 10 in a front view offset at 90°,
FIG. 12 shows a rear view of a packaging machine with apparatuses for the transport and handling of cassettes.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The main component of an apparatus for the transport of blanks 20 is containers or cassettes 21, in which prefabricated, that is to say punched blanks 20 are accommodated in stacked form. The present exemplary embodiment is concerned with the handling of blanks 20, such as are used in the cigarette industry for the production of hinge-lid packs. Blanks 20 with a contour typical of the design of packs of this type are shown in FIG. 3.
The cassettes 21 are re-usable containers which circulate between the production shop for the blanks 20, especially a paper factory, and the processing shop, especially a cigarette factory. In the paper factory, the cassettes 21 are filled with blank stacks 22. Filled cassettes 21 are then transported to the processing factory in a suitable way, for example in a stacked position on pallets or the like (FIG. 4). In the processing factory, the cassettes 21 are emptied by the extraction of the blank stacks 22. The empty cassettes 21 are then nested in one another in a specific way and returned to the paper factory in a space-saving manner as empty stock.
In the present exemplary embodiment, each cassette 21 consists of four chambers 23, each receiving a blank stack 22. The elongated chambers 23 extend over the entire width of the cassettes 21 which are rectangular, as seen in the plan view. For the loading and emptying of the cassettes 21, the chambers 23 are open on two sides, in particular at the top and on one longitudinal side of the cassettes 21, namely the open side 24.
The load-bearing member of the cassette 21 is a stable bottom wall 25. The blank stacks 22 rest on this. To delimit the chambers 23 from one another, vertical partition wall members are arranged on the top side of the bottom wall 25. In the present exemplary embodiment, the chambers 23 are limited by vertical webs connected firmly to the bottom wall 25.
Here, between adjacent chambers 23, there are two equally large partition webs 26 lying in one plane and an edge web 27 located at the edge of the bottom wall 25 and extending in the same plane. In the present case, the edge web 27 has a smaller cross-section, in particular a smaller dimension in the direction parallel to the blank stacks 22, than the partition webs 26. The edge web 27 is located on that side (closing side 28) of the cassette which is closed for the retention of the blank stacks 22.
Arranged on the shorter sides of the cassette 21 are side webs 29 corresponding to the partition webs 26 and one respective corner web 30 corresponding to the edge webs 27. The outer chambers 23 are limited on the outside of the cassette 21 by the side webs 29 and corner webs 30.
The above-described webs 26, 27, 29, 30 are, on the one hand, aligned in the planes parallel to the chambers 23. Furthermore, however, the webs are also aligned in rows transversely relative to the chambers 23, that is to say in the longitudinal direction of the cassette 21.
The edge webs 27 and corner webs 30 on the closing side 28 of the cassette 21 are equipped with supporting members for the bearing of the blank stacks 22. In the present case, arranged laterally respectively on the edge webs 27 and on one side of the corner web 30 are vertical supporting strips 31, against which edge regions of the blanks 20 bear positively with a fit. The special, approximately trapezoidal cross-sectional form of the supporting strips 31 emerges from the form of the blanks 20 which is characteristic of hinge-lid packs. In particular, these are designed, in the region of a front wall of the hinge-lid pack and in the region of adjoining side tabs, to form side walls of the hinge-lid pack with tooth-shaped projections 32. The blanks 20 bear by means of these triangular projections 32 or by means of their oblique edges 33 against oblique supporting faces of the correspondingly shaped supporting strips 31. Formed in the region where these adjoin the edge web 27 or corner web 30 is a vertical groove 34, into which the outermost tip of the projection 32 penetrates and is thereby protected against damage.
The cassettes 21 filled with blank stacks 22 are designed to be stacked, for example on pallets. In order, at the same time, to prevent relative shifts of the cassettes 21 in relation to one another, an inter-meshing of the cassettes 21 arranged above one another is provided. In the exemplary embodiment illustrated, the side webs 29 and the corner webs 30 are equipped, on the top side and underside, with projections for positive engagement. As shown, arranged on the top side of the abovementioned webs 29, 30 are conical centering lugs 35 which, during stacking (FIG. 4), penetrate positively into corresponding conical depressions 36 on the underside of the identical corresponding webs 29, 30. The abovementioned members have a self-centering effect during the stacking of the cassettes 21.
However, the suitability of the (empty) cassettes for a space-saving stacking nested in one another is of particular importance. For this purpose, orifices 37 and additional orifices 38 are arranged in the bottom wall 25. These are matched in terms of size and shape to the partition webs 26, so that the latter can be inserted alternately through the orifices 37 or additional orifices 38 for the nesting of cassettes 21.
The orifices 37 and 38 are respectively arranged aligned in longitudinal and transverse rows. Located on the edge of the bottom wall 25, particularly on its narrow sides, and between adjacent edge webs 27 or corners webs 30 are recesses 39 which are open to the side. The dimensions of these correspond to the cross-sectional dimensions of the side webs 29.
The number of orifices 37 and that of the additional orifices 38 correspond respectively to the number of partition webs 26 of a cassette 21. The partition webs 26 of two cassettes 21 can thereby be guided completely or partially through the bottom wall 25 of a third cassette. The arrangement is such that orifices 37 are arranged respectively in the same plane as the partition webs 26 serving for limiting a chamber 23. Here, the distance between two adjacent partition webs 26 is filled by an orifice 37. The additional orifices 38 are arranged centrally between two adjacent orifices 37, that is to say centrally within a chamber 23, and are aligned with the orifices 37, as seen in the longitudinal direction of the cassette 21. This results in two rows of orifices 37 and additional orifices 38 extending in the longitudinal direction of the cassette 21 and in recesses 39 at the edges.
Two cassettes 21a, 21b designed in this way, offset transversely, are nested one in the other, specifically in such a way that the partition webs 26 of one cassette 21a are guided from below or from the underside of the bottom wall 25 through the orifices 37 of the second cassette 21b. At the same time, the side webs 29 of the cassette 21a enter the recesses 39 of the cassette 21b. The partition webs 26 and the side webs 29 of the two cassettes 21a, 21b are accordingly aligned in transverse planes, but offset relative to one another, in such a way that the edge webs 27 and corner webs 30 of the two cassettes 21a, 21b extend next to the bottom wall 25 of the other respective cassette 21a, 21b (FIG. 9). For this purpose, the two cassettes 21a, 21b are joined together, offset at 180° relative to one another.
A pair of cassettes 21a, 21b plugged together in the abovementioned way constitutes a stack unit 40 which already allows a space-saving storage of the cassettes 21a, 21b.
However, because of the design of the cassettes 21, two stack units 40, 41 with cassettes 21a, 21b on the one hand and 21c, 21d on the other hand can be nested one in the other, in such a way that a block-shaped structure, particularly a stack block 42 consisting of four cassettes 21a to 21d, is obtained. The outer dimensions of the stack block 42 are only slightly larger than the dimensions of an individual cassette 21.
For this purpose, two stack units 40, 41 are plugged one into the other with their bottom walls 25 remote from one another. The stack units 40, 41 are at the same time offset in the longitudinal direction relative to one another by the amount of half the width of a chamber 23. The partition webs 26 and side webs 29 of the stack units 40, 41 are thereby assigned alternately to the additional orifices 38 of the confronting bottom wall 25 of the other stack unit 40, 41. The respective partition webs 26 and side webs 29 enter the additional orifices 38 (FIGS. 10 and 11). The altogether four cassettes 21 are easy to handle, particularly storable with a small space requirement, as a unit, namely as a stack block 42.
For the loading of the cassettes 21, the stack blocks 42 and stack units 40, 41 are taken apart again in the opposite direction of movement.
The partition webs 26, edge webs 27, side webs 29 and corner webs 30 are extended as far as the underside of the bottom wall 25. In particular, in this region, the bottom wall 25 is equipped with bevelled head-like projections 43 corresponding to the abovementioned webs 26, 27, 29, 30. With the cassettes 21 filled and stacked, the projections 43 on the underside of the bottom wall 25 rest on the upper ends of the webs 26, 27, etc. During the stacking of inter-nested empty cassettes 21, particularly stack blocks 42 (FIG. 10), the projections 43 penetrate in a centring manner into orifices 38 of adjacent cassettes 21.
The cassettes 21 appropriately consist of a one-piece, preferably cast material, especially of plastic. In the present exemplary embodiment, depressions are formed in on the underside of the bottom wall 25, specifically, on the one hand, centre depressions 44 extending in the longitudinal mid-plane and, on the other hand, retaining depressions 45 formed in on one edge, specifically on the edge confronting the closing side 28. The first-mentioned depressions 44 extend respectively over the width of a chamber 23, and projections 43 arranged between adjacent centre depressions 44 serve as a stop for positioning the cassette 21, especially during unloading.
The retaining depressions 45 are important for the (automatic) transport of the cassettes 21.
During the supply of blanks 20 to packaging machines, the (filled) cassettes 21 are appropriately introduced into the circuit of an overhead conveyor, especially with the features of German Patent Application P3820735 (and of a corresponding U.S. Pat. No. 5,007,522 which is expressly incorporated herein by reference). In this older proposal, the overhead conveyor is equipped with bogie trucks 46 (FIG. 12) which are movable along a running rail 47 above the production and packaging machines. Located on the bogie trucks 46 are material holders 48 which are designed so that they can transport either reels of web-shaped packaging material or cassettes 21.
For this purpose, the material holders 48 are equipped with rigid downward-diverging carrying arms 49. Attached to the lower ends of these are horizontal carrier spars 50 directed transversely, that is to say projecting on one side. On these rest the articles to be transported, particularly reels of different diameters or cassettes 21. The carrier spars 50 are attached rigidly, as parts projecting, that is to say jutting out, on one side, to the carrier arms 49. Reels rest with their circumferential surface on the carrier spars 50. To protect a reel resting vertically on the carrier spars 50 against transverse or tilting movements, the material holder 48 is designed with rigid side holders which rest supportingly against side faces of the reel. These side holders, assigned respectively in pairs to a reel, are formed by fixed side fences 60, 62, 64 of the carrier spars 50. For this purpose, these side fences are made step-shaped in the longitudinal direction, so that depressions or recesses of differing length in the direction of the carrier spars 50 are obtained. The vertical or slightly divergingly inclined step faces of the steps thus formed constitute the side fences 60, 62, 64. The distances between side fences 60 to 64, interacting in pairs, are designed to accommodate reels of different axial dimensions. A reel with the smallest dimension in the axial direction rests in an approximately central depression or recess 66 of the carrier spars 50. This reel is held laterally by the side fences 64 arranged at the shortest distance from one another. A depression or recess 68, formed at a higher level and with supporting surfaces on both sides of the central recess 66, serves to receive a larger reel between side fences 62. Finally, there is provided a depression or recess 70 of the smallest depth, but of the greatest width, for receiving the largest reels between the outer side fences 60. Where the transport of cassettes 21 is concerned, an upward-directed nose 51 (FIGS. 6 and 7) attached to the free end of each of the carrier spars 50 penetrates into the retaining depression 45 of the cassette 21. This is thus protected against shifts on the carrier spars 50 during transport.
In the region of a packaging machine 52 (FIG. 12), the filled cassettes 21 are received by a first vertical conveyor 53 from the bogie truck 46 of the overhead conveyor and are conveyed downwards. The cassette 21 is deposited by the vertical conveyor 53 on a machine conveyor 54. This is arranged to run longitudinally at the rear of the packaging machine 52.
In the region of an unloading station 55, the blank stacks 22 are extracted from the cassette 21 in succession as a result of an upward movement, specifically by means of a stack lifter 56. This grasps a respective blank stack 22 and conveys it upwards and feeds the blank stacks 22 to a blank magazine (not shown) located on the machine.
The empty cassettes 21 are transported further on the machine conveyor 54 as far as a second vertical conveyor 57. This takes over the empty cassettes 21 and transfers them to a bogie truck 46 or to a material holder 48 of the latter.
The nesting of several cassettes 21 in one another is carried out at an unloading station of the continuous overhead conveyor, especially manually. | 4y
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This utility application is a divisional application of U.S. Ser. No. 13/067,710 filed on Jun. 22, 2011 which claims priority to Taiwan Application Serial Number 099123227, filed on Jul. 15, 2010.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to an epitaxial substrate and fabrication thereof, and more in particular, to an epitaxial substrate having a nano-rugged and non-patterned epitaxial surface and fabrication thereof
[0004] 2. Description of the Prior Art
[0005] Compound semiconductor materials, such as GaN, AlGaN, AlInGaN, and other III-V group compounds, or CdTe, ZnO, ZnS, and other II-VI group compounds, have been used for a wide variety of substrates of microelectronic devices including transistors, field emission devices, and optoelectronic devices, but not limiting the above described.
[0006] Taking a GaN-based microelectronic device as an example, a major problem in manufacture is that the GaN semiconductor layer manufactured must have low defect density to ensure the performance of the GaN-based microelectronic device. It is understood that one of these contributors for defects is the lattice mismatch between the substrate and the GaN layers grown on the substrate. Therefore, though the GaN layer has been grown on the sapphire substrate, but it is well known that the GaN layer is preferably grown on the AlN buffer layer previously formed on the SiC substrate to reduce the defect density, especially to reduce the density of threading dislocations. Even though there are these considerable progresses, it is still the goal desired to reach to reduce the defect density continuously on the research.
[0007] It is also well-known that the condition of epitaxy is controlled to achieve the lateral epitaxy by use of the substrate with patterned surface, which benefits in preferred orientation of epitaxy, to reduce the defect density or control defects. For example, a GaN semiconductor layer can be formed on the sapphire substrate with patterned surface in lateral epitaxial way to control dislocations in extending laterally to reduce the density of threading dislocations.
[0008] However, all of the prior arts regarding manufacture of the epitaxial substrate with patterned surface must utilize a photolithography process. Obviously, the prior arts regarding manufacture of the epitaxial substrate with patterned surface have high manufacture cost and slow production speed.
SUMMARY OF THE INVENTION
[0009] Accordingly, one scope of the invention is to provide an epitaxial substrate and fabrication thereof. In particular, an epitaxial surface of the epitaxial substrate according to the invention is non-patterned, but thereon still benefits a compound semiconductor material in lateral epitaxy to grow an epitaxial layer with excellent quality. Moreover, the method of manufacturing the epitaxial substrate according to the invention has advantages of low cost and rapid production.
[0010] An epitaxial substrate according to a preferred embodiment of the invention includes a crystalline substrate. The crystalline substrate has an epitaxial surface. In particular, the epitaxial surface of the crystalline substrate is nano-rugged and non-patterned.
[0011] A method of fabricating an epitaxial substrate, according to a preferred embodiment of the invention, firstly, is to prepare a crystalline substrate which has an epitaxial surface. Next, the method according to the invention is to deposit a poly-crystalline layer of a material on the epitaxial surface of the crystalline substrate. Then, the method according to the invention is to etch the grain boundaries of the poly-crystalline layer by a first wet etching process. Afterward, the method according to the invention is to take the etched poly-crystalline layer as a mask, and to etch the regions within the grain boundaries of the ploy-crystalline layer by a plasma etching process. Finally, the method according to the invention is to remove the etched poly-crystalline layer by a second wet etching process, where the epitaxial surface of the crystalline substrate is nano-rugged and non-patterned.
[0012] In one embodiment, the epitaxial surface of the crystalline substrate has an average surface roughness (Ra) in a range from 100 nm to 400 nm.
[0013] In one embodiment, the epitaxial surface of the crystalline substrate has a mean peak-to-valley height (Rz) in a range from 50 nm to 350 nm.
[0014] In practical application, the crystalline substrate can be formed of sapphire, SiC, GaN, GaAs, ZnO, Si, ScAlMgO 4 , SrCu 2 O 2 , YSZ(Yttria-Stabilized Zirconia), LiAlO 2 , LiGaO 2 , Li 2 SiO 3 , LiGeO 3 , NaAlO 2 , NaGaO 2 , Na 2 GeO 3 , Na 2 SiO 3 , Li 3 PO 4 , Li 3 AsO 4 , Li 3 VO 4 , Li 2 MgGeO 4 , Li 2 ZnGeO 4 , Li 2 CdGeO 4 , Li 2 MgSiO 4 , Li 2 ZnSiO 4 , Li 2 CdSiO 4 , Na 2 MgGeO 4 , Na 2 ZnGeO 4 , Na 2 ZnSiO 4 , or other commercial materials provided for epitaxy.
[0015] In practical application, the material to form the poly-crystalline layer can be Ge, ZnO, ZnS, CdSe, CdTe, CdS, ZnSe, InAs, InP, Si, or metal/silicide where the metal can be Al, Ni, Fe or other metal, and the silicide can be SiAl, SiZn, SiNi or other silicide.
[0016] In one embodiment, the poly-crystalline layer can be deposited on the epitaxial surface of the crystalline substrate by an LPCVD (low pressure chemical vapor deposition) process, an PECVD (plasma-enhanced chemical vapor deposition) process, a sputtering process, or a thermal evaporation process.
[0017] In one embodiment, the poly-crystalline layer has a thickness in a range from 20 nm to 2000 nm.
[0018] Compared to the prior arts, the epitaxial surface of the epitaxial substrate according to the invention is nano-rugged and non-patterned, and still benefits a compound semiconductor material in growing epitaxial layers with excellent quality. Moreover, the method of manufacturing the epitaxial substrate according to the invention has advantages of low cost and rapid production.
[0019] The advantage and spirit of the invention may be understood by the following recitations together with the appended drawings.
BRIEF DESCRIPTION OF THE APPENDED DRAWINGS
[0020] FIG. 1 illustratively shows an epitaxial substrate with nano-rugged and non-patterned surface according to a preferred embodiment of the invention.
[0021] FIGS. 2A through 2C illustratively show a method according to a preferred embodiment of the invention to fabricate an epitaxial substrate, for example, as shown in FIG. 1 .
[0022] FIG. 3 is an atomic force microscopy image of morphology of a sapphire substrate fabricated according to the invention.
[0023] FIG. 4 is a transmission electron microscope image of an un-doped GaN layer grown on a sapphire substrate fabricated according to the invention.
[0024] FIG. 5A is an atomic force microscopy image of an un-doped GaN layer grown on a sapphire substrate fabricated according to the invention.
[0025] FIG. 5B is an SEM image of an etched un-doped GaN layer grown on a sapphire substrate fabricated according to the invention.
[0026] FIG. 5C is an atomic force microscopy image of an un-doped GaN layer grown on a sapphire substrate with smooth surface.
DETAILED DESCRIPTION OF THE INVENTION
[0027] Referring to FIG. 1 , FIG. 1 is a cross-sectional view of an epitaxial substrate 1 according to a preferred embodiment of the invention. The epitaxial substrate 1 can be provided for a compound semiconductor material in epitaxy, such as GaN, AlGaN, AlInGaN, or other III-V group compounds, or CdTe, ZnO, ZnS, or other II-VI group compounds.
[0028] As shown in FIG. 1 , the epitaxial substrate 1 according to the invention includes a crystalline substrate 10 . The crystalline substrate 10 has an epitaxial surface 102 .
[0029] Different from the prior arts, the epitaxial surface 102 of the crystalline substrate 10 is nano-rugged and non-patterned. It is noted that similar to the epitaxial substrates with patterned surfaces of the prior arts, the epitaxial substrate 1 according to the invention can also benefit the compound semiconductor material in lateral epitaxy.
[0030] In one embodiment, the epitaxial surface 102 of the crystalline substrate 10 has an average surface roughness (Ra) in a range from 100 nm to 400 nm.
[0031] In one embodiment, the epitaxial surface 102 of the crystalline substrate 10 has a mean peak-to-valley height (Rz) in a range from 50 nm to 350 nm.
[0032] In practical application, the crystalline substrate 10 can be formed of sapphire, SiC, GaN, GaAs, ZnO, Si, ScAlMgO 4 , SrCu 2 O 2 , YSZ(Yttria-Stabilized Zirconia), LiAlO 2 , LiGaO 2 , Li 2 SiO 3 , LiGeO 3 , NaAlO 2 , NaGaO 2 , Na 2 GeO 3 , Na 2 SiO 3 , Li 3 PO 4 , Li 3 AsO 4 , Li 3 VO 4 , Li 2 MgGeO 4 , Li 2 ZnGeO 4 , Li 2 CdGeO 4 , Li 2 MgSiO 4 , Li 2 ZnSiO 4 , Li 2 CdSiO 4 , Na 2 MgGeO 4 , Na 2 ZnGeO 4 , Na 2 ZnSiO 4 , or other commercial materials provided for epitaxy.
[0033] Referring to FIGS. 2A through 2C and FIG. 1 , these figures of sectional views illustratively show a method according to a preferred embodiment of the invention to fabricate the epitaxial substrate 1 , for example, as shown in FIG. 1 .
[0034] As shown in FIG. 2A , the method according to the invention, firstly, is to prepare a crystalline substrate 10 . The crystalline substrate 10 has an epitaxial surface 102 .
[0035] In practical application, the crystalline substrate 10 can be formed of sapphire, SiC, GaN, GaAs, ZnO, Si, ScAlMgO 4 , SrCu 2 O 2 , YSZ(Yttria-Stabilized Zirconia), LiAlO 2 , LiGaO 2 , Li 2 SiO 3 , LiGeO 3 , NaAlO 2 , NaGaO 2 , Na 2 GeO 3 , Na 2 SiO 3 , Li 3 PO 4 , Li 3 AsO 4 , Li 3 VO 4 , Li 2 MgGeO 4 , Li 2 ZnGeO 4 , Li 2 CdGeO 4 , Li 2 MgSiO 4 , Li 2 ZnSiO 4 , Li 2 CdSiO 4 , Na 2 MgGeO 4 , Na 2 ZnGeO 4 , Na 2 ZnSiO 4 , or other commercial materials provided for epitaxy.
[0036] Next, the method according to the invention is to deposit a poly-crystalline layer 12 of a material on the epitaxial surface 102 of the crystalline substrate 10 , as shown in FIG. 2B . Also shown in FIG. 2B , the poly-crystalline layer 12 has grain boundaries 122 .
[0037] In practical application, the material to form the poly-crystalline layer 12 can be Ge, ZnO, ZnS, CdSe, CdTe, CdS, ZnSe, InAs, InP, Si, or metal/silicide where the metal can be Al, Ni, Fe or other metal, and the silicide can be SiAl, SiZn, SiNi or other silicide.
[0038] In one embodiment, the poly-crystalline layer 12 can be deposited on the epitaxial surface 102 of the crystalline substrate 10 by an LPCVD (low pressure chemical vapor deposition) process, an PECVD (plasma-enhanced chemical vapor deposition) process, a sputtering process, or a thermal evaporation process.
[0039] In one embodiment, the poly-crystalline layer 12 has a thickness in a range from 20 nm to 2000 nm.
[0040] Then, the method according to the invention is to etch the grain boundaries 122 of the poly-crystalline layer 12 by a first wet etching process. The sectional view of the etched poly-crystalline 12 is shown in FIG. 2C .
[0041] In a case, taking a sapphire as the substrate 10 , various etching solutions, which can be used to etch the grain boundaries 122 of poly-crystalline layer 12 , and the compositions of these etching solutions are listed in Table 1. Table 1 lists four etching solutions including Secco solution, Sirtl solution, Wright solution, and Seiter solution.
[0000]
TABLE 1
composition (Mol %)
etching solution
solvent 1)
HF
oxizers 2)
Secco
67.6
32.2
0.17
Sirtl
71.2
26.3
2.5
Wright
78.5
16.1
5.4
Seiter
78.5
5.9
15.6
1) H 2 O + CH 3 COOH(H Ac );
2) CrO 3 + HNO 3
[0042] Furthermore, because the etching solutions listed in Table 1 cannot etch the sapphire substrate 10 , these etching solutions can etch the grain boundaries 122 of the poly-crystalline layer 12 until the epitaxial surface 102 of the sapphire substrate 10 underneath the grain boundaries 122 is exposed. Otherwise, as the case, these etching solutions just etch the grain boundaries 122 of the poly-crystalline layer 12 to certain depth where the epitaxial surface 102 of the sapphire substrate 10 underneath the grain boundaries 122 is not exposed.
[0043] Afterward, the method according to the invention is to take the etched poly-crystalline layer 12 as a mask, and to etch the regions within the grain boundaries 122 of the ploy-crystalline layer 12 by a plasma etching process. Finally, the method according to the invention is to remove the etched poly-crystalline layer 12 by a second wet etching process, where the epitaxial surface 102 of the crystalline substrate 10 is nano-rugged and non-patterned.
[0044] In practice, the second wet etching process can use the etching solution as the same as that used in the first wet etching process.
[0045] In one embodiment, the epitaxial surface 102 of the crystalline substrate 10 has an average surface roughness (Ra) in a range from 100 nm to 400 nm.
[0046] In one embodiment, the epitaxial surface 102 of the crystalline substrate 10 has a mean peak-to-valley height (Rz) in a range from 50 nm to 350 nm.
[0047] In practice, the Ra and Rz values of the epitaxial surface 102 of the crystalline substrate 10 can be controlled by controlling the thickness and grain size of the poly-crystalline layer 12 and etching conditions.
[0048] Taking a sapphire substrate as an example, the morphology of the sapphire substrate sample fabricated according to the invention is shown in FIG. 3 that is an atomic force microscopy (AFM) image. It is evident that the morphology of the epitaxial substrate exhibits nano-rugged and non-patterned surface.
[0049] A transmission electron microscope (TEM) image of a sapphire substrate sample (labeled as NRSS) fabricated according to the invention is shown in FIG. 4 , and an un-doped GaN layer (labeled as u-GaN) grown on the epitaxial surface of the sapphire substrate is also shown in FIG. 4 . FIG. 4 evidently shows that the un-doped GaN layer has low density of dislocations which are laterally extending dislocations rather than threading dislocations.
[0050] An AFM image of an un-doped GaN layer grown on the aforesaid NRSS sample is shown in FIG. 5A . The un-doped GaN layer grown on the NRSS sample is etched at 180 ° C. for 1 minute in KOH aqueous solution, an SEM image of the etched un-doped GaN layer is shown in FIG. 5B . The etched pits shown in FIG. SB are just evidence of threading dislocations. By statistical counting, the density of threading dislocations of the un-doped GaN layer grown on the NRSS sample is about 3.6×10 6 cm −2 . In contrast, an AFM image of an un-doped GaN layer grown on a sapphire substrate with smooth surface is shown in FIG. 5C . Obviously, compared to FIG. 5A , FIG. 5C shows less smooth surface. By statistical counting, the density of threading dislocations of the un-doped GaN layer grown on the sapphire substrate with smooth surface is about 1×10 9 cm −2 . Obviously, compared to the epitaxial substrates with smooth epitaxial surface, the epitaxial substrate according to the invention can reduce density of dislocations, especially for density of threading dislocations.
[0051] Similar to the epitaxial substrates with patterned surfaces of the prior arts, the epitaxial substrate 1 with nano-rugged and non-patterned surface according to the invention can also benefit the compound semiconductor material in lateral epitaxy to reduce density of defects and to enhance quality of epitaxial layers. Table 2 lists measured photoelectric properties of sample labeled as NRSS that the GaN layer is grown on the sapphire substrate with nano-rugged and non-patterned surface fabricated according to the invention. In contrast, Table 2 also lists measured photoelectric properties of sample labeled as PSS that the GaN layer is grown on the sapphire substrate with patterned surface, and measured photoelectric properties of sample labeled as FSS that the GaN layer is grown on the sapphire substrate with smooth surface.
[0000]
TABLE 2
forward voltage
peak emission wavelength
luminous intensity
sample
(Volt.)
(nm)
(a.u.)
NRSS
3.71
457.21
5.71 × 10 −7
PSS
3.60
450.30
5.50 × 10 −7
FSS
3.69
459.51
3.33 × 10 −7
[0052] With photoelectric properties listed in Table 2, it is evident that the photoelectric properties of sample NRSS with sapphire substrate according to the invention are close to those of sample PSS with patterned sapphire substrate, and are better than those of sample FSS with smooth sapphire substrate.
[0053] It is emphasized that different from the prior arts, the method of fabricating the epitaxial substrate according to the invention is not only without the need of a photolithography process, and but also without the introduction of complicated process. Therefore, it is obvious that the method according to the invention has advantages of low manufacture cost and rapid production speed.
[0054] With the example and explanations above, the features and spirits of the invention will be hopefully well described. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teaching of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims. | 4y
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This application is a continuation in part of Ser. No. 10/571,925 filed on Mar. 15, 2006 now abandoned as the national stage of PCT/EP2004/008875 filed on Aug. 7, 2004 and also claims Paris Convention priority of DE 103 48 500.7 filed on Oct. 18, 2003, the entire disclosures of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
The present invention concerns a method and a device for adjusting the gap dimensions and/or an offset between a movable flap of a vehicle and the remaining vehicle body. The method comprises initial fitting and retention of the flap in a roughly adjusted installation position flush with the body. Finally, the flap is finely adjusted such that predetermined values of the gap dimensions and/or the offset are matched as closely as possible.
The assembly of vehicles includes i.a. the installation of flaps. Flaps are, in particular, the doors of the vehicle, but also the hood and trunk lids or rear flap. The flaps are inserted into corresponding openings in the body and are movably mounted to the body via hinges or joints at a suitable installation position, such that they can be rotated about an axis of rotation. A suitable installation position is characterized by the flaps being substantially flush with the remaining body or with previously fitted neighboring flaps, and have a uniform separation from the remaining body or the neighboring flaps. One thereby strives for predetermined gap dimensions and a particular offset in the installation position. The flap can be movably fixed to the body in the finely adjusted, installation position.
A flap is conventionally mounted to the hinges or joints on the body in a roughly adjusted installation position. At least one wedge-shaped element, a so-called key collar is inserted into the gap between the flap and the remaining body or the neighboring flaps, to fit the flap into the opening, flush with the body. The flap is then finely adjusted such that predetermined gap dimensions are matched as closely as possible. A worker moves the flap in the opening and examines the gap dimensions and/or the offset. He/she must always see to it that the key collar keeps the flap flush with the body. When the flap is in the finely adjusted installation position, it is finally movably fixed to the hinges or joints on the body. The use of a key collar is, however, very expensive and produces relatively inaccurate results which are difficult to reproduce and document.
German patent application 102 51 393, filed on Nov. 5, 2002 by Dr.-Ing. Charalambos Tassakos, also extensively describes another method or device for adjusting the gap dimensions and/or an offset between a movable flap of a vehicle and the remaining body. This patent application describes a so-called mechanical key collar simulation which is characterized in that the flap is pulled by a pneumatic suctioning means against a mechanical stop in the roughly adjusted installation position to effect fine adjustment, wherein the mechanical stop is fixed relative to the remaining body and is freely pivotable about an axis of rotation which extends in a substantially vertical direction. The mechanical stop thereby represents an extrapolation of the surface of the remaining body, relative to which the gap dimensions and/or the offset of the flap is to be adjusted. The pneumatic suctioning means pulls the flap against the mechanical stop and thereby into the surface of the remaining body such that it is substantially flush with the remaining body. The proposed method uses a mechanical stop and a pneumatic suctioning means instead of a key collar. For this reason, the above-described method is also called mechanical key collar simulation.
The mechanical key collar simulation is particularly well suited for adjusting the gap dimensions and/or the offset between the side doors and the remaining body of a vehicle. It is easier to fit flaps on the sides of a vehicle, since the surfaces of the vehicle body, or of the already fitted flaps map over into the surface of the flap to be fitted in a substantially planar fashion. However, use of the mechanical key collar simulation is difficult when the surfaces of the remaining body or of previously fitted flaps do not map over into the surface of the flap to be fitted in a flat fashion, rather at a certain angle. This is the case e.g. in the region of the motor hood, the trunk lid or the rear flap of a vehicle, where the flaps merge into the fenders. The use of mechanical key collar simulation at these locations either requires great effort or is completely impossible.
Moreover, in the mechanical key collar simulation, the mechanical stop, which is guided to the measuring location using a robot or a similar manipulation device, causes relatively large forces to act on the surfaces of the remaining body or previously fitted flaps and on the surfaces of the flaps to be fitted. These forces are even increased by the pneumatic suctioning means which pulls the flap to be fitted against the mechanical stop. These forces may deform the body or the flaps, which could produce inaccuracies during adjustment of the gap dimensions or the offset.
During the preliminary construction phase of a motor vehicle, the body of the car is in the form of welded together sheet metal with pivotally attached flaps (doors, trunk lid, and hood). In this state, the body of the car is not equipped with locks, door handles or fixtures. Prior to final assembly, it is necessary to check whether or not the gaps between the flaps and the remaining portions of the motor vehicle body are within acceptable tolerances. Towards this end, the flaps must temporarily be held in a defined position relative to the remaining portions of the body for the duration of the measurement. Prior art uses so-called key collars for this purpose. A proposed further development of the key collars is referred to as a mechanical key collar simulation (see DE 102 51 393 A1).
Departing from the above-described prior art, it is the underlying purpose of the present invention to provide a simpler and less expensive key collar simulation which still permits highly accurate fitting of a flap into the remaining vehicle body, irrespective of the angle between the surface of the body or a fitted flap and the surface of the flap to be fitted.
SUMMARY OF THE INVENTION
The object of the invention is achieved by a method and with an associated device. The inventive method provides for key collar simulation in association with mounting and alignment of a moveable flap to a body of a motor vehicle. The method comprises the following steps:
a) initially mounting the flap to the body in a roughly adjusted installation position for motion about an axis of rotation; b) optically detecting, following step a) and prior to painting the motor vehicle as well as prior to final mounting of locks, handles, and fixtures to the flaps and remaining body, actual values for a gap or offset between the flap and remaining portions of the body; c) generating, in dependence on the actual values detected in step b) and on specified desired values corresponding to a properly aligned position of the flap, drive signals for variation of a position and orientation of the flap relative to the remaining portions of the body using at least one actuating element cooperating with the flap; and d) regulating the at least one actuating element using the drive signals to pivot the flap about the axis of rotation for approximating the properly aligned position of the flap.
The invention is therefore neither directed to the installation of the flaps in the body nor to measurement of gap widths during the final stages of assembly for purposes of quality control. In accordance with the invention, the offset between the flap and the remaining portions of the body is compared with specified desired values thereof and the flap is automatically driven for pivoting about its rotational axis such that the actual position of the flap relative to the remaining portions of the body corresponds to the specific desired values thereof. Moreover, this procedure is performed prior to the final assembly of the motor vehicle body. As soon as the flap is in the defined reproducible pivot position, the width of the gap can be measured relative to the remaining positions of the vehicle body. The invention is therefore directed to a procedure which is utilized only in the preliminary constructional phase during which neither locks nor handles are attached to the flaps and the surrounding portions of the vehicle body. The method in accordance with the invention is carried out during a stage of assembly in which the flaps have been previously mounted in a pivotable fashion to the remaining portions of the motor vehicle body. After carrying out the procedure in accordance with the invention, the motor vehicle body with the pivotally attached flaps is painted and prepared for final assembly during which the locks, fixtures and handles are attached to the flaps and to the associated portions of the motor vehicle body. In this end assembly phase, the geometry of the gaps between the flaps and the remaining portions of the motor vehicle body can be easily measured, since the flaps are properly held in a defined and reproducible pivotal position with respect to the remaining portions of the motor vehicle body by means of the locks and associated fixtures. This is, however, not the case during the preliminary constructional phase of assembly to which the invention as amended is explicitly directed. The present invention can therefore be described as a “regulated key collar simulation”.
In accordance with the invention, for fine adjustment,
the actual values for the gap dimensions and/or the offset between the roughly adjusted flap and the remaining body, are optically detected; depending on the detected actual values and predetermined desired values of the gap dimensions and/or the offset, drive signals are generated for at least one actuating element acting on the flap to facilitate variation of the position and orientation of the flap relative to the body; and the gap dimensions and/or the offset are approximated to the specified desired values through driving the at least one actuating element via the drive signals.
One important aspect of the present invention is that the method operates in a contact-free manner in the region of the measuring location where the actual values of the gap dimensions and/or the offset are detected. This permits detection of the actual values even in the region of the measuring location, which is not possible with mechanical key collar simulation.
The overall inventive method is realized in the form of a control or regulation means, wherein the control or regulating variable is the transition (gap dimensions and/or offset) between the flap to be fitted and the remaining body. The control or regulation means may be realized with little expense using software which runs on a suitable computer, in particular, a microprocessor. Realization of the key collar simulation mainly by software gives the user a particularly great deal of flexibility concerning e.g. predetermination of any desired values of the gap dimensions and/or the offset between the flap to be fitted and the remaining body. In this manner, an amount of lead may e.g. be set for fine adjustment such that doors which are fitted in the sides of the body slightly protrude past the body. Such fitting of the flaps into the remaining body with an amount of lead can reduce wind noises in the region of the gaps.
Moreover, the key collar simulation regulated or controlled in accordance with the invention permits fitting of a flap into the opening of a vehicle body with extremely high accuracy, since the gap dimensions and/or the offset are detected with extreme accuracy by suitable optical detecting means and the gap dimensions and/or the offset are detected in a contact-free manner such that the body or flap are not deformed.
In accordance with an advantageous further development of the present invention, the gap dimensions and/or the offset is/are controlled to the predetermined desired values. This further development comprises a regulation means for approximating the transition (gap dimension and/or offset) between the flap to be fitted and the remaining body to at least one predetermined desired value. The transition is preferably exactly adjusted to the desired value, but under certain circumstances, a control deviation may be produced. The regulation means usually attempts to zero the control deviation between the detected actual value and the predetermined desired value or the transition between the flap to be fitted and the remaining body. The regulation algorithm is preferably implemented in a computer program which can be run on a computer, with the optically detected actual values of the transition being supplied to the computer program. Alternatively, the computer program can be supplied with digital records from a measuring location, wherein the computer program assesses the records to detect at least one actual value of the transition (the gap dimensions and/or the offset) at the measuring location. Depending on the detected actual values and on the specified desired values of the transition, the computer program generates drive signals for the actuating elements and guides the drive signals to the actuating elements either directly or indirectly via suitable interfaces.
In accordance with a preferred embodiment of the invention, the desired values of the gap dimensions and/or the offset of the flap are predetermined in relation to the remaining body in such a manner that the transition between the flap and the remaining body at a measuring location is zero. A zero transition corresponds to a flap which is flush with the remaining body. A transition can be defined either as subjective opinion of one or more observer/s (e.g. the members of staff responsible for quality assurance) or objectively by a certain mathematical description. A mathematical description of the transition can ensure that the transition can be detected and adjusted in an exact and reproducible manner.
U.S. Pat. No. 4,498,776, U.S. Pat. No. 4,666,303, U.S. Pat. No. 5,416,590 and U.S. Pat. No. 5,999,265 disclose e.g. a mathematical description of the transition. These documents disclose various possible analytic descriptions of a transition between two parts, preferably between a flap and the remaining body of a vehicle. The mathematical definitions of a transition given in these documents are hereby incorporated by reference. There are of course many other feasible analytical descriptions of a transition.
Alternatively, the desired values for the gap dimensions and/or offset of the flap are predetermined relative to the remaining body in such a manner that a positive transfer of more than zero is obtained between the flap and the remaining body at a measuring location. A positive transition corresponds to a flap which is fitted into the remaining body in such a manner that it slightly projects outwardly past the surface of the remaining body when the vehicle is at rest. Such presetting of the desired values is important, in particular, for fitting the side doors into the remaining body, since wind noises that may be produced in the region of the gaps during traveling can thereby be reduced.
In accordance with a preferred embodiment of the present invention, the flap is initially mounted to the body in the roughly adjusted installation position such that it can be rotated about an axis of rotation with at least one actuating element acting on the flap to vary a position and orientation of the flap about the axis of rotation. The flap can thereby be moved about the axis of rotation without being deformed. In this manner, the gap dimensions and/or the offset between the movable flap and the remaining body of a vehicle can be adjusted with much greater accuracy.
In accordance with another advantageous further development of the invention, the actual values of the gap dimensions and/or offset between the flap of the vehicle and the remaining body are initially detected at a first measuring location and approximated to specified desired values, and the actual values are subsequently detected at least one further measuring location and approximated to specified desired values. This further development proposes detection of the gap dimensions and/or offset between a roughly adjusted flap and the remaining body at different measuring locations, fine adjustment of the flap in this manner and fitting thereof in a predetermined position and orientation relative to the remaining body. Application of the method according to this further development is particularly easy when means for optical detection of the gap dimensions and/or the offset are moved to the different measuring locations for performing the measurement using an industrial robot or another manipulation device.
A flap which is finely adjusted relative to the remaining body is preferably movably disposed on the body, i.e. mounted to hinges or joints. It is however, also feasible that fitting of the flap in the finely adjusted installation position merely serves to check whether or not a certain flap can be fitted in the specified installation position of the body while thereby observing the specified desired values for the gap dimensions and/or the offset. If this is possible, the flap can be removed again from the body after fitting e.g. for subsequent painting, separately from the remaining body.
In the event that the flap cannot be fitted into the remaining body as desired or if the transition between the flap to be fitted and the remaining body cannot be adjusted to a desired value, different measures can be taken. The flap and/or the remaining body bordering the flap could be plastically deformed in such a manner that the transition at selected measuring locations approximates the specified desired values if the deviation between the actual values, approximated to the desired values, and the specified desired values exceeds a predetermined limit value.
If the deviation between the actual values, approximated to the desired values, and the specified desired values exceeds a specified limit value at at least one measuring location, a request can be made to the production line for production of further flaps and/or a request can be made to the installation line for installation of further flaps on the remaining body of vehicles, wherein the production and/or installation parameters of the production line or the installation line can be varied in dependence on the response. The flap which is improperly fitted, positioned and oriented may thereby be left in that location or a new flap may be fitted. With this feedback, a type of (slow) control loop can be closed to optimize production and installation of further flaps in such a manner that the flaps can be optimally fitted into the body. The slow control loop is then superposed onto the (faster) inventive regulation or control means for fitting a flap into the remaining body.
Realization of the inventive method in the form of a computer program is particularly important. The computer program is programmed to perform the inventive method and can be run on a computer, in particular, a microprocessor. In this case, the invention is realized by the computer program with this computer program representing the invention in the same way as the method for the performance of which the computer program is suited. The computer program is preferably stored on a storage element. The storage element may, in particular, be an electronic storage medium, e.g. a random access memory (RAM), a read only memory (ROM) or a flash memory.
A further solution of the object of the present invention is effected by a device of the above-mentioned type, the device having means for fine adjustment comprising:
detecting means for optical detection of the actual values for the gap dimensions and/or the offset between the roughly adjusted flap and the remaining body; computing means for generating drive signals for at least one actuating element in dependence on the detected actual values and specified desired values for the gap dimensions and/or the offset; and at least one actuating element, wherein the actuating element acts on the flap to vary the position and orientation of the flap relative to the remaining body, and approximates the gap dimensions and/or the offset to the specified desired values via driving with the drive signals.
In accordance with an advantageous further development of the present invention, the detecting means comprise a camera laser unit. Such a camera laser unit comprises at least one illumination means, in particular a laser, and at least one image recording means, in particular a CCD camera or a CMOS camera. A camera laser unit of this type is also called a laser sensor and is e.g. extensively described in German patent application 103 11 247, filed on Mar. 14, 2003 by Inos Automationssoftware GmbH. The construction and function of such a camera laser unit disclosed in this document is hereby incorporated by reference.
The actuating element may be designed in any way. A hydraulically or pneumatically driven cylinder would e.g. be feasible as an actuating element. In a preferred embodiment of the invention, the at least one actuating element comprises an electromotor. The at least one actuating element preferably comprises an electric stepping motor.
Finally, the device may comprise an industrial robot or another manipulation device to which the detecting means are mounted and which moves the detecting means to predetermined measuring locations for detecting the actual values for the gap dimensions and/or the offset between the flap of a vehicle and the remaining body at those locations.
Further features, applications and advantages of the invention can be extracted from the following description of embodiments of the invention which are shown in the drawing. The features described or shown represent the object of the invention either individually or in arbitrary combination irrespective of their summary in the claims or their dependencies and irrespective of their formulation or illustration in the description or drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows an inventive device for adjusting gap dimensions and/or an offset between a movable flap of a vehicle and the remaining vehicle body in accordance with a preferred embodiment;
FIG. 2 shows a section of the inventive device according to FIG. 1 with detecting means for optical detection of the gap dimensions and/or the offset between the flap to be fitted and the remaining body in accordance with a preferred embodiment;
FIG. 3 shows a schematic view of a transition of less than zero between a flap and the remaining vehicle body;
FIG. 4 shows a schematic view of a transition of approximately zero between a flap and the remaining vehicle body;
FIG. 5 shows an image recorded by optical detection means of the inventive device with a transition of less than zero between a flap and the remaining vehicle body;
FIG. 6 shows an image recorded by optical detection means of the inventive device with a transition of approximately zero between a flap and the remaining vehicle body;
FIG. 7 shows an image recorded by optical detection means of the inventive device with a transition of more than zero between a flap and the remaining vehicle body; and
FIG. 8 shows a control loop structure to illustrate the inventive method for adjusting the gap dimensions and/or the offset between a flap and the remaining body of a vehicle in accordance with a preferred embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows an inventive device which is designated in total by reference numeral 1 . The device 1 serves for adjusting the gap dimensions and/or the offset between a movable flap 2 of a vehicle and the remaining body 3 of the vehicle. FIG. 1 shows a vertical section through the vehicle, transverse to a longitudinal vehicle axis. The movable flap 2 in this example is a motor hood or a trunk lid. The remaining body 3 of the vehicle is represented by the fenders.
The movable flap 2 is initially mounted to the remaining body 3 in a roughly adjusted installation position via hinges or joints such that the flap 2 can be rotated about an axis of rotation. The movable flap 2 is fitted in the roughly adjusted installation position in a special installation space of the body 3 , preferably using an industrial robot or other manipulation device. The movable flap 2 , fitted in the roughly adjusted installation position, is held by the hinges and optionally also by the industrial robot or the manipulation device.
After rough adjustment, the flap 2 must be fitted into the installation space of the body 3 into a finely adjusted installation position. Fine adjustment is required to be able to exactly maintain specified values of the gap dimensions and/or the offset. This is particularly important, since inaccurate gap dimensions or excessive offset of the flap 2 relative to the remaining body 3 of a vehicle can produce disturbing wind noises during travel. Moreover, the visual impression of the vehicle to the viewer would be impaired by irregular gap dimensions or excessive offset. This applies, in particular, to vehicles having decorative strips or vehicle lights which do not border a gap, but which extend to both sides of the gap. In such cases, an irregular or excessive gap or offset would be particularly noticeable.
After fine adjustment of the flap 2 relative to the remaining body 3 , the flap 2 is either fixed on the body 3 in the finely adjusted installation position or is removed, e.g. for separate painting of the flaps 2 and body 3 . In the latter case, fitting of the flap 2 into the remaining body 3 merely serves to determine whether or not the shape of the flap 2 or of the remaining body permits satisfactory installation of the flap 2 into the provided installation space of the body 3 during later final assembly, thereby observing the specified desired values for the gap dimensions and/or offset.
The inventive method concerns, in particular, fine adjustment of the movable flap 2 relative to the remaining body 3 of the vehicle. The inventive device 1 comprises detection means 4 having an image detection means 8 which is preferably designed as CCD (Charged Coupled Device) camera or as CMOS (Complimentary Metal Oxide Semiconductor) camera (see FIG. 2 ). The detection means 4 serve for optical detection of the actual values for the gap dimensions and/or the offset between the roughly adjusted flap 2 and the remaining body 3 .
The detection means 4 are explained in more detail below with reference to FIG. 2 . Detection means 4 are designed as a camera laser unit or as a so-called laser sensor, and comprise a carrier element 5 to which the image detection means 8 is mounted. An illumination means 6 is additionally mounted to the carrier element 5 to illuminate a measuring location 7 in the region of a transition between the flap 2 and the remaining body 3 and/or images a pattern on the surfaces to be detected at the measuring location 7 . The illumination means 6 is designed e.g. as a laser. It is theoretically sufficient for the detection means 4 to comprise only one optical image detection means 8 . The illumination means 6 which illuminates the measuring location 7 and provides it with a pattern considerably facilitates detection of the gap dimensions and/or of the offset between the flap 3 and the remaining body 2 , thereby also improving the accuracy.
In the embodiment of FIG. 2 , the laser 6 generates a sharply defined light line 9 in the region of the measuring location 7 , which extends across the gap, from the flap 2 and the body 3 . The illumination means 6 could, of course, also generate light lines extending parallel to the gap at the facing edges of the flap 2 and body 3 , as is disclosed e.g. in DE 199 10 699 or the corresponding U.S. Pat. No. 6,529,283. In accordance with the invention, any method for detecting the transition between the flap 2 and the body 3 may be used.
The detection means 4 are mounted to a distal end of an industrial robot arm 10 or to any other manipulation device. The robot or the manipulation device moves the detection means 4 to predetermined measuring locations 7 for detecting the actual values of the gap dimensions and/or the offset between the flap 3 of the vehicle and the remaining body 2 , at that location.
The device 1 also comprises (see FIG. 1 ) computing means 11 which are preferably designed in the form of a personal computer (PC). The computing means 11 comprise an electronic storage element 26 on which a computer program is stored and which is programmed to perform the inventive method. The storage element 26 is preferably a flash storage. In order to run the computer program, it is transferred to a computing device 28 via a data connection, either completely, in sections or corresponding to commands. The computing device 28 is preferably designed as a microprocessor.
The computing means 11 serve i.a. to generate drive signals 24 for actuating elements 12 . The drive signals 24 are determined in dependence on the detected actual values 21 ist for the gap dimensions and/or the offset between the roughly adjusted flap 2 and the remaining body 3 and in dependence on the predetermined desired values 21 soll for the gap dimensions and/or the offset. The actual values 21 ist detected by the detection means 4 are transferred to the computing means via data lines 13 . The drive signals 24 generated by the computing means 11 are transferred to the actuating elements 12 via data lines 14 . The actuating elements 12 vary the relative position and orientation between the flap 2 and the remaining body 3 . The actuating elements 12 preferably move the flap 2 about the axis of rotation defined by the hinges or joints via which the flap 2 is mounted to the body 3 .
In the present embodiment, the actuating elements 12 are formed as electric linear motors or stepping motors which act on the flap 2 at effective points 15 to vary the position and orientation of the flap 2 relative to the remaining body 3 . The actuating elements 12 or the effective points 15 are preferably disposed on a side of the flap 2 opposite to the hinges or joints. The actuating elements 12 can move the flap upwards and downwards and preferably also to the left and right ( FIG. 1 ).
The transition between the flap 2 and the remaining body 3 is determined by the gap dimensions and/or the offset of the flap 2 relative to the remaining body 3 . The transition may be defined either as subjective impression of one or more observer/s (e.g. the members of staff responsible for quality assurance) or objectively through a certain mathematical description. A mathematical description of the transition is e.g. disclosed in U.S. Pat. No. 4,498,776, U.S. Pat. No. 4,666,303, U.S. Pat. No. 5,416,590 and U.S. Pat. No. 5,999,265. These documents disclose different possible analytic descriptions of the transition between two parts, preferably between a flap and the remaining vehicle body and are hereby incorporated by reference with respect to their mathematical definition of a transition. Of course, there are many other feasible analytical descriptions of a transition.
FIG. 3 illustrates a situation in which the separation 21 between a measuring straight line 20 contacting the surface of the remaining body 3 and the surface of the flap 2 is substantially less than zero, i.e. the transition amount is relatively large. To correct this negative transition, the flap 2 is moved in a controlled manner in the direction of arrow 12 ′ by the actuating elements 12 in accordance with the invention until the separation 21 has reached a specified desired value, preferably zero. Reference numeral 16 designates a first function for extrapolating a surface of the flap 2 beyond its end. Reference numeral 17 designates a second function for extrapolating a surface of the body 3 beyond its end. The intersection between the two functions 16 , 17 is designated with reference numeral 18 . Reference numeral 19 designates a vertical straight line which bisects the opening angle between the functions 16 , 17 . Reference numeral 20 designates the measuring straight line which intersects the vertical straight line 19 at right angles and which tangentially contacts the surface of the body 3 .
FIG. 4 shows the flap 2 in its finely adjusted installation position after termination of fine adjustment. The separation 21 has been reduced to almost zero through inventive regulation of the installation position.
FIGS. 5 to 7 show different images recorded by the optical detection means 4 in the region of a measuring location 7 . FIG. 5 shows the image recorded by a laser sensor with a transition of −5 mm. FIG. 6 shows the same image, however, with a transition of 0 mm, and FIG. 7 shows the same image, however, with a transition of +5 mm. The images recorded by the optical detection means 4 in accordance with FIGS. 5 through 7 are evaluated in the computing means 11 to detect the transition (gap dimension and/or offset) between the flap 2 and the remaining body 3 at the measuring location 7 . The computing means 11 then generate the drive signals 24 for the actuating elements 12 in dependence on the detected actual values 21 ist and in dependence on the specified desired values 21 soll (preferably to a zero transition).
FIG. 8 shows a control loop structure to explain the inventive method. The detection means 4 (laser sensor) detect an actual value of the transition 21 ist and the measured actual value 21 ist is subtracted from a specified desired value for the transition 21 soll . A transition=0 is preferably preset as desired value 21 soll . The difference between the desired and actual values is called the control deviation 22 . The control deviation 22 is supplied to a regulation means 23 which is preferably realized in the form of software. Towards this end, a corresponding computer program is run on the computing means 11 of the device 1 . The regulation means 23 generate the drive signals 24 for the actuating elements 12 on the basis of the control deviation 22 . The drive signals 24 therefore constitute the controlled variable for regulation. Driving the actuating elements 12 with the generated drive signals 24 causes displacement of the flap 2 relative to the remaining body 3 (position and/or orientation) by a certain amount. This displacement of the flap 2 is symbolized by an operational block 25 . Displacement 25 of the flap 2 produces a new actual value 21 ist of the transition which is, in turn, detected by the detection means 4 . Repeated run of the control loop structure of FIG. 8 causes approximation of the actual value 21 ist of the transition to the specified desired value 21 soll of the transition. If the desired deviation is zero, the control loop structure is run until the actual value 21 ist of the transition is equal to the desired value 21 soll of the transition. | 4y
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FIELD OF THE INVENTION
This invention relates to a method and apparatus for assembling heat exchanger elements and particularly to such a method and apparatus to automatically receive and couple such elements when inserted.
BACKGROUND OF THE INVENTION
Heat exchangers of the plate type are comprised of pairs of preformed plates joined to other pairs at their ends by integral bosses and separated at their middle section by air centers or corrugated fins, the plates and fins all being brazed together so that each pair of plates becomes a tube for carrying refrigerant, the bosses serving as a manifold for permitting refrigerant flow from one tube to another, and the fins facilitating heat exchange between the tubes and air flowing outside the tubes. U.S. Pat. No. 4,470,455 issued to Sacca describes such a plate type heat exchanger in detail.
The assembly of the plate type heat exchanger elements into a core ready for brazing has typically been carried out largely by hand operations. Specifically, the first step is to assemble a fin element between two plates and crimp the plates together into subassemblies where their bosses connect, and then manually stack such subassemblies along with side plates into a fixture which holds each subassembly in place.
It is desirable to enhance the assembly practice by an improved method and machine for assembly. In particular it has been found that the process is improved in terms of automation and in terms of reducing spacing in the fixture if it is begun by joining the plates together into pairs that eventually become tubes and inserting the plate pairs and side plates into a fixture and then inserting the centers between the plates. It is desirable to have a machine to perform the assembly operations to reduce the manufacturing expense and otherwise improve the efficiency of the assembly practice. It has been demonstrated that the machine assembly of plate pairs, air centers and side plates into a pallet is practical.
It is known to automatically assemble other styles of heat exchanger cores as shown in the U.S. Pat. No. 4,321,739 to Martin et al. In Martin et al the tubes are first inserted into blocks carried by chains and the centers are then loaded between the tubes which are well spaced by the blocks. The tubes and centers are gathered together as the blocks are removed from one tube at a time. Thus tubes and centers are arranged in alternate rows and headers are joined to the ends of the tubes and tanks are joined to the headers to couple the tubes together. The tubes do not directly coact and they have smooth exteriors which facilitate the insertion of centers, as contrasted with the plate and center type which requires that the plates each mate with their neighbors as well as to sandwich the air centers. Further, the plate edges protrude in a way to interfere with center insertion so that large spacings between the plates would be required to permit center insertion. The large spacings necessitate a large gathering distance and also allow centers to get out of position so that centers can interfere with the coupling of the plates during the gathering process.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a practical method and apparatus especially adapted to the automatic assembly of plates and centers into a heat exchanger core.
The invention is carried out in an apparatus for assembling pairs of plates and air centers for a heat exchanger core by a pallet system comprising; a frame movable in a longitudinal direction, a plurality of blocks in the frame supported along each side of the frame and mounted for limited movement in the frame in the longitudinal direction, each block having a slot for receiving an end of a pair of plates and positioned opposite a similar block for receiving an opposite end of the pair of plates, and means for selectively engaging the blocks for moving the blocks and the frame longitudinally, the engaging means being effective to position the blocks at a loading station and to vary the spacing of the blocks to facilitate insertion of elements into the frame.
The invention is further carried out in a process for assembling pairs of plates and air centers for a heat exchanger core in a pallet having plate holders by the method of inserting plates into holders comprising the steps of: positioning a holder at a loading station in a position spaced from adjacent holders so that adjacent parts do not interfere with plate insertion, dropping a pair of plates into the holder, then moving the holder toward an adjacent holder to mate one pair of the plates with a previously loaded pair of plates, and repeating the positioning, dropping and moving steps for the next adjacent holder until the holders are filled as desired.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other advantages of the invention will become more apparent from the following description taken in conjunction with the accompanying drawings wherein like references refer to like parts and wherein:
FIG. 1 is an elevation partly in section of stacked plates for a heat exchanger core assembled by the method and apparatus of the invention,
FIG. 2 is an isometric view of an indexed pallet system according to the invention,
FIG. 3 is a plan view of the right half of a pallet and associated screw assembly of FIG. 2,
FIG. 4 is a side view of the pallet of FIG. 3,
FIG. 5 is an end view of the pallet of FIG. 3 with a plate of FIG. 1 loaded into the pallet and with an end plate removed to show block detail,
FIG. 6 is a partly broken away end view of the block of FIG. 5, and
FIG. 7 is a partial plan view of the dual screw arrangement of FIG. 2 and associated pallets.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A portion of the heat exchanger core to be assembled by the apparatus and method of the invention is shown in FIG. 1. Plate pairs 10 which will form tubes when brazed consist of plates 12 and 14 which when stacked form a heat exchanger core adapted to be used as an evaporator. The plate pairs 10 are stacked to define a space 16 therebetween for the flow of air. The space 16 includes a corrugated metal center or fin 17 with louvers struck out therefrom for increasing the heat exchange efficiency. Only a portion of the center 17 is illustrated.
For standard plate pairs 10 the individual plates 12 and 14 are configured identically, one of the plates is simply inverted and rotated 1800 relative to the other. Each plate has a flat peripheral edge portion 18 and the portions 18 of the two plates are formed so as to engage one another prior to braze jointure. Thus each pair of plates, when brazed, forms a tube for refrigerant. Inlet and outlet manifolds 24, 26 are formed by outwardly offset and generally circular portions 28 in each end of plates 12 and 14. An opening 30 is provided in the top surface at one end and an opening 32 is provided with an outwardly raised flange portion 34 at the other end. Thus, the plates are designed so that, when stacked, the flange portion 34 surrounding opening 32 fittingly engages the opening 30. This provides a registering relationship between the plates of two adjacent tubes.
In some cases the plates 12 and 14 are not configured identically in the sense that an opening 30 may be omitted to structure the manifold for fluid flow management through the core. The plate on either end of the core will be equipped with an inlet or outlet fitting at the opening 30 or 32. Thus the core is made up primarily of "standard" plate pairs combined with a few "special" plate pairs. In any event they all couple together in the same manner. The plate and heat exchanger structures are more fully described in the U.S. Pat. No. 4,470,455 to Sacca.
The general organization of the assembly machine is shown in FIG. 2. A pallet 40 comprises an open-sided frame 42 with vertical end plates 44 at each corner of a horizontal base plate 45. Four rods 46 supported by the end plates 44 extend longitudinally along each side to pass through and hold a plurality of perforated blocks 48 which can slide a limited amount along the rods. A coil spring 49 under compression surrounds alternate rods 46 on each side between an end plate 44 and the nearest block 48 to hold the blocks together against the other end of the frame unless the spring force is overcome. The blocks 48 each have a slot 50 for receiving the edges of a plate pair 10 adjacent an offset portion 28. Each block also has an outboard cam follower 52 extending to the side of the pallet. A lead screw 54 with its axis parallel to the rods 46 at each side of the path of the pallet engages just a few of the cam followers 52 at a given time. The lead screws 54 are synchronously rotated by servomotors 56 to advance the corresponding blocks 48 longitudinally so as to precisely position the blocks and to advance the entire pallet 40 as well. A microprocessor based controller 57 controls the servomotors. The lead screws are positioned at a loading station for plate pairs 10 and the pallets 40 are carried to the loading station by a power and free conveyor 58 which depends on a frictional contact to drive the pallet. The lead screws engage the cam followers of the blocks and positively and precisely position the blocks at a feed plane where plate pairs are dropped into the slots 50 in the blocks 48. As shown in FIG. 2 the first few blocks are holding plate pairs 10 and subsequent blocks are prepared to receive a plate pair being inserted as indicated by an arrow 60.
The width of the blocks is such that when they are nested together the adjacent plate pairs 10 are stacked together as shown in FIG. 1. A critical function of the pallet system is that the pitch of the lead screw 54 is greater than the width of the blocks so that the few blocks that are actively engaged by the lead screws are spaced far enough to permit insertion of the plate pairs 10 without interference by an adjacent plate pair and the adjacent pairs are moved into a nested assembly as they are released by the lead screws. The plate pairs 10 may not necessarily be loaded at the same station since it may be more convenient to have separate loading stations for each type of plate pair, standard or special. The conveyor 58 carries the pallet from one station to the next. At each station the blocks 48 are spaced apart as they pass the feeding plane and the proper plate pairs are inserted into empty slots according to a preset program. Centers 17 are also supplied to the pallet in the same manner. Center insertion occurs after all the plates are inserted since the plate pairs 10 position and laterally support the centers.
A center loading station is shown in FIG. 2 downstream from the plate loading station. Lead screws 62 driven by servomotors 64 are on opposite sides of the conveyor 58. The optimum spacing of the blocks for center insertion is less than for the plate pair insertion. Thus the lead screws 62 at the center loading station have a smaller pitch than those at the plate pair loading station. Accordingly, the pallet 40 can provide various insertion spacings under control of the lead screws at a various stations.
A special feature at the center loading station is an auxiliary lead screw 66 drivingly coupled to each lead screw 62 by a shaft 68 but spaced from the lead screw 62 by a distance of perhaps one half the length of a pallet 40. The purpose of the lead auxiliary screw 66 is to engage a pallet 40' which is waiting to enter the center loading station and positively advance the pallet at a rate determined by the motor 64 speed. In the absence of the lead screw 66 the pallet would be advanced by the power and free conveyor 58 which relies on friction to move the pallet and is accordingly limited in its ability to accelerate the pallet. The positive advancement is most advantageous when the waiting pallet is touching or nearly touching the pallet in the station. By positively advancing the waiting pallet 40' it can be accelerated quickly for positioning in the station under control of the lead screw 62, thus minimizing the time lapse between the last center insertion in one pallet 40 and the first center insertion in the next pallet. The benefit of minimizing the time lapse is to allow the supply of centers to proceed at a more uniform rate. In the most efficient arrangement the centers are fed to the pallet directly from the machine making the centers. That machine operates best at a constant output rate but it can vary its rate somewhat to accommodate the time lapse between pallets, providing that the time lapse is small. In other words, it is not desirable to stop the supply of centers each time a pallet is positioned in the loading station but some slow down is permissible. The positive advancement of the waiting pallet by the lead screw 66 in conjunction with the control by lead screw 62 permits its precise positioning in the loading station in the minimum time.
Details of the assembly machine are better shown in FIGS. 3, 4, 5 and 6 and include some elements not shown in FIG. 2. The base plate 45 has a large central aperture 70 and a short pedestal 72 at each end between the end plates 44. A platen 74 (FIG. 5) is supported on the pedestals with its upper surface flush with the bottom edges of the elements to be loaded into the pallet and is the support for centers when they are first loaded and are not yet held by the adjacent plates. The platen 74 also is used to lift the assembled core out of the pallet via an elevator, not shown, which pushes up through the large aperture 70 in the base plate.
The slot 50 in each block is configured to the shape of the plates 10 so that the plate pairs nest in the slot. The blocks also have relief to accommodate the offset portions 28 of the plates. Each block 48 has, in addition to the slot 50 and the cam follower 52, two flat side faces 75 which abut similar faces in adjacent blocks, two large holes 76 and two small holes 77 receiving the rods 46. The four holes are positioned at corners of a rectangle and two diagonal small holes 77 are surrounded by a boss 78 protruding beyond the faces 75 on one side of the block and containing a bushing 80 for sliding on the rods 46. The other set of diagonal holes 76 are large enough to receive the bosses 78 of the adjacent block. For the blocks to fit together with the adjoining faces 75 in contact two block types (for each side of the pallet) are used alternately so that each boss 78 of one block will align with and fit in the corresponding large hole 76 of the adjacent block. One type of block rides on two of the rails and the other type rides on the other two rails. The bosses protrude toward the end of the pallet 40 that contains some free space for block movement. The springs 49 on two of the rods reside in the space and extend between the end plates 44 and the bosses 78 of the end block to press the blocks together in the absence of the lead screws. When the lead screws engage some of the blocks the springs 49 are compressed due to the separation of those blocks. The frame 42 is moved by the lead screws 54 via forces acting through the blocks and the springs 49 if the springs are in the leading edge of the pallet. The other end of the pallet may be positioned in the front in which case the force from the lead screws is delivered directly by the blocks to the frame 42.
The lead screws 54 comprise helical threads 82 having a pitch determined by the block thickness and the block separation appropriate for a particular loading station. The thickness of each thread is sufficient to span the distance between adjacent cam followers 52. This assures that each block will be positively positioned by the screw threads. The cam followers 52 are essentially elliptical to accommodate the pitch angle of the threads.
FIG. 7 shows the lead screw 62 connected to the auxiliary lead screw 66 and coupled respectively to a pallet 40 in the center loading station and a waiting pallet 40'. The screw driving shaft 66 is supported in three spaced bearing blocks 84 and is driven at one end by a motor (not shown). Each screw 62, 68 is mounted on the shaft 66 and keyed thereto by a pin 86 passing through a hub 88 on the screw and through the shaft. The screw 62 is the same as the screw 56 at the plate loading station except for a smaller lead and thread width to conform to the smaller block spacing required for the center insertion. The pallets 40, 40' are shown with one closely following the other. A bumper 90 is fixed to the trailing end of each pallet for desired spacing of the waiting pallet from the one being loaded. This allows the leading blocks of the waiting pallet to smoothly mesh with the screw 68. In operation, the waiting pallet 40' is brought into contact with the rear end of the pallet 40 by the conveyor 58 preferably before the pallet 40 enters the loading station. When the first blocks of the pallet 40' reach the screw 68 the blocks will be captured by the screw so that the pallets 40 and 40' will be advanced together by the screws 62 and 68. When the pallet 40 is fully loaded with centers the motors 64 will accelerate to quickly remove the pallet 40 and simultaneously move the waiting pallet 40' into the station with accurate positioning for the insertion of the next center dropped into the loading plane.
Accurate positioning of the blocks is assured by driving the blocks directly by the lead screws and by driving the lead screws by servomotors under computer control. The amount of rotation of the servomotors and thus the position of each block is precisely controlled by the computer program. | 4y
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DESCRIPTION
1. Technical Field
My invention relates to a mechanism for supporting and driving a wing flap. More particularly, it relates to a folding truss type flap support/drive mechanism which is adapted to produce a flap movement closely approaching a rectangular Fowler motion verses deflection angle progression.
2. Background Art
Many different types of mechanisms for supporting, guiding and driving a trailing edge wing flap have been developed for a variety of aircraft. They include (1) a simple hinge, (2) a four-bar upright linkage, (3) a four-bar overhead linkage, (4) variable curvature tracks, (5) circular arc tracks and (6) a folding beam four-bar linkage.
There are one or more obvious deficiencies associated with several of the previously mentioned mechanisms. The simple hinge has a low take-off Fowler motion and requires large fairings with high cruise drag. The four-bar upright linkage has deficiencies similar to the simple hinge but to a lesser degree. The four-bar overhead linkage has high actuation forces. The variable curvature tracks have wear problems with roller carriage. The circular arc tracks have low take-off Fowler motion.
My folding truss mechanism was developed in an effort to minimize the cruise drag associated with flap mechanisms fairings, and at the same time achieve the desirable characteristics of the more effective flap systems now available (e.g. the system used on the Boeing 767 aircraft).
DISCLOSURE OF THE INVENTION
The trailing edge flaps of a high performance aircraft must fulfill two functions. They must provide a high lift to drag ratio take-off configuration and a high lift coefficient landing configuration. A high lift drag ratio for take-off can be accomplished by trailing edge flap positions with high Fowler motion (aft motion, which increases wing projected area), a single converging slot between flap and spoiler trailing edge, and a small flap deflection angle. The high lift coefficient for landing requires high Fowler motion, two relatively narrow converging slots (for double slotted flap) and high flap deflection angles. Theoretically, the best Fowler verses deflection angle progression would be rectangular. This would require two separate mechanisms, one to drive the flap straight aft and another to rotate it. This is not a practical solution. Therefore, a single flap mechanism, that approaches the rectangular progression the closest, is the most desirable.
My folding truss flap support mechanism is a compound four-bar linkage scheme. It is simple in concept and for a single-slotted flap configuration contains the same number of links and joints as the flap mechanism for the Boeing 767 aircraft. All joints are simple pin joints or monoballs, which provide positive structural rigidity and precise positioning control for the mechanism, compared with systems such as curved track roller carriage flap mechanisms. All the links in the support mechanism but one have uni-axial loads, which mean lower structural weight than for mechanisms with links subjected to bending loads.
In basic makeup, my folding truss flap support mechanism comprises a drive link which is pivotally attached at its upper end to an upper frame portion of a wing section forward of the flap, e.g. the main wing body, for fore and aft pivotal movement about a first axis. A second pivot axis is established below and aft of the first pivot axis, by a pivotal connection between the lower end of a support link and a fixed frame portion of the wing structure. The upper end of the support link is pivotally attached to both the upper end of a swing link and the after end of a slave link, to form a third pivot axis. A fourth pivot axis is formed at a forward connection of the flap to the lower end of the drive link. A fifth pivot axis is formed where the lower end of the swing link makes a rearward connection to the flap. The drive link, the portion of the flap which extends between the fourth and fifth axis, the swing link, and wing structure form a first four-bar linkage. The support link, the drive link, the wing section structure which interconnects the first and second pivot axis and the slave link form a second four-bar linkage. This linkage provides a moving anchor point for the swing link. The moving anchor point permits the swing link to be relatively short and to move the rear connection to the flap a greater distance aft, through a shallow arc, for maximum Fowler motion. The shallow arc is necessary for flap transition control to take-off position. The compound motion of the support link/swing link combination, not only provides the desired shallow arc for the flap carriage rear support, but it also creates an abrupt hook motion near the end of the travel to provide ideal flap position for landing.
My folding truss mechanism can be adapted to a variety of flap configurations. These include a single-slotted flap, a double slotted flap (main/aft) and a double slotted flap (vane/main). The support can be provided by an underneath flap support mechanism or by a varied end support flap mechanism.
My folding truss mechanism can be located underneath the flap in a very compact envelope, and requires an enclosure fairing smaller than that of a track flap (Boeing 757 flap, for example). Or, it can be located at the ends of the individual flap panels and contained within the contour of the wing trailing edge, requiring no flap mechanism fairings.
The flap actuation hinge moments and power requirements are low for my folding truss mechanism and the air loads on the flap always tend to move it in a stowing direction, which is a desirable failsafe characteristic for the flap in the event of actuation failure.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a wing showing a single slotted flap and my folding truss mechanism in a stowed position;
FIG. 2 is a view like FIG. 1, but showing the flap and the truss mechanism in a take-off configuration;
FIG. 3 is a view like FIGS. 1 and 2, but showing the flap and the truss mechanism in a landing configuration;
FIG. 4 is a view like FIGS. 1-3 of a fixed vane main flap and a folding truss mechanism in a stowed position;
FIG. 5 is a view like FIGS. 1-4, of the mechanism shown in FIG. 4, in a take-off configuration; and
FIG. 6 is a view like FIGS. 1-5, of the mechanism shown in FIGS. 4 and 5, in a landing configuration;
FIG. 7 is a view like FIGS. 1-6, but of a double-slotted flap and a folding truss mechanism in a stowed position;
FIG. 8 is a view like FIGS. 1-7 of the mechanism shown by FIG. 7, in a take-off configuration;
FIG. 9 is a view like FIGS. 1-8, of the mechanism shown by FIGS. 7 and 8, in a landing configuration; and
FIG. 10 is a graph of Fowler motion verses flap angle, comparing the Fowler verse deflection angle progression of the folding truss mechanism of the present invention with a tracked flap, a hinged flap, and the theoretically best motion.
BEST MODE FOR CARRYING OUT THE INVENTION
As previously mentioned, the best Fowler verses deflection angle progression would be rectangular. This is shown in FIG. 10. FIG. 10 also shows that the folding truss flap support mechanism of the present invention accomplishes this task better than many presently used flap mechanisms.
The versatility of the folding truss flap mechanism of the present invention is evident from the number of flap configurations which can be achieved.
FIGS. 1-3 show an embodiment of the folding truss mechanism of the present invention as a part of a single-slotted flap, with underneath support.
The basic mechanism comprises two four-bar linkages coupled together in a manner which produces a compound motion of the flap rear support point.
The first or primary four-bar linkage, herein the "overhead" linkage, comprises a drive link 10 which is pivotally attached to fixed structure 12 (it is grounded) for pivotal movement about a pivotal axis 14. Fixed structure 12 may be a bracket on the wing rear spar 13. At its opposite the drive link 10 is pivotally attached to a forward end of a flap carriage link 16, for pivotal movement about a pivot axis 18. Flap carriage link 16 is connected to and supports the flap 20. The primary linkage also includes a swing link 22 which is pivotally attached at one of its ends to the flap carriage link 16, for pivotal movement about a pivot axis 24. Link 22 is pivotally attached at its opposite end to the second four-bar linkage.
The second four-bar linkage provides a moving anchor point for the swing link 22. It comprises an upright support link 26. Link 26 is attached to the fixed structure (it is grounded) through a support beam 28, a slave link 30 and drive link 10. A short support link 29 connects the forward end of beam 28 to the forward wing section.
The pivotal connection between the upper end of drive link 10 and fixed frame structure 12 is herein referred to as the "first" pivot axis. The "second" pivot axis is formed where the lower end of the support link 26 is connected to the beam 28. The "third" pivot axis is formed where the upper ends of the support link 26 and the swing link 22 are connected to the aft end of the slave link 30. The "fourth" pivot axis is established where the lower end of the drive link 10 is connected to the flap member. A "fifth" pivot axis is established where the lower end of the swing link makes a rear connection to the flap member. A "sixth" pivot axis is established where the forward end of the slave link 30 is attached to the drive link 10. The six pivot axes are the basic axes of the mechanism. The particular order followed in the numbering of these axes is arbitrary.
Line 33 is a reference line for use in comparing the change in position of the flap 20 as it is moved from or to its stowed position to or from its take-off or landing positions.
As the drive link 10 rotates in a counterclockwise direction, it moves the flap carriage link 16 aft. Simultaneously, the drive link 10 moves the slave link 30 aft, as part of the second four-bar linkage. The moving anchor point, formed by a pivot joint 31 between the slave link 30 and the support link 26, permits the relatively short swing link 22 to move the flap carriage rear support a much greater distance aft, through a shallow arc, for maximum Fowler motion. The shallow arc is necessary for flap transition control to take-off position. The compound motion of the support link/swing link combination, not only provides the desired shallow arc for the flap carriage rear support, but it also creates an abrupt hook motion (indicated by line 35 in FIG. 1) near the end of the travel to provide ideal flap position for landing. The shallow arc motion of the flap carriage rear support is similar to that which could be achieved with a very long aft link in a single overhead four-bar linkage flap support scheme. A principle advantage of my folding truss mechanism is that it can achieve a desired motion, similar to other mechanisms requiring much greater stowage space.
The mechanism drive scheme shown, is a rotary actuator 32 connected to the drive link 10 through an actuator arm 34 and a push rod 36. Arm 34 is pivotally connected to rod 36 for pivotal movement about a pivot axis 38. The opposite end of rod 36 is pivotally attached to both the drive link 10 and the slave link 30, for pivotal movement about a common pivot axis 40. Other drive schemes are also possible, including direct rotary actuation of the drive link 10, linear hydraulic actuator or ball screw actuator drives.
The flap 20, as shown, is attached to the flap carriage fitting by spherical joint connected flap hanger links 42, 44 at three of the four flap support locations. One of the forward flap attachments is a single mono-ball joint for stability. The hangers 42, 44 would accommodate conical or skewed cylindrical flap motion as well as structural deflections. The hangers 42, 44 could be eliminated if spherical joints were used at several locations in a mechanism to provide limited lateral compliance and angular adjustment of certain links. The upper joint of the drive link 10 is a rigid pin joint for reacting side loads.
The flap mechanism fairing consists of a fixed forward segment 46 and a movable aft segment 48. The movable part 48 of the fairing is connected to the flap carriage fitting by a fairing slave link 50, which moves the fairing away from the flap 20 during deployment to clear the moving mechanism. This flap fairing 46, 48 is proportionally smaller than that for any other flap mechanism with similar motion.
The flap deployment sequence begins with an initial nose down motion as the drive link 10 moves the flap 20 aft. The flap 20 then begins to rotate in a nose up direction until it reaches the take-off position, with flap deflection at ten degrees (10°), as shown in FIG. 2. The Fowler motion at the take-off position is approximately 68.5% of the Fowler motion at maximum flap deflection. The maximum flap deflection is thirty-six degrees (36°), as shown in FIG. 3, at which point the Fowler motion is 56.3% of the flap chord and 15.3% of the wing chord. The flap chord is 27.3% of wing chord. The slot developed between the flap 20 and the trailing edge of the spoiler 52 is approximately 1.56% of flap chord for take-off and 1.7% for landing. Of course, these numerical values are for the specific embodiment that is illustrated in FIGS. 1-3. In other embodiments, the values most likely would be different.
The flap configuration shown in FIGS. 1-3 is based on an existing wing trailing edge geometry, and does not reflect the maximum capability of this mechanism scheme.
The flap mechanism scheme just described could also be adapted to incorporate an aft flap with an actuation mechanism similar to the main flap. This would result in a double slotted flap configuration which would have much better performance characteristics than the single slotted configuration.
Referring to FIGS. 4-6, the third embodiment involves the flap control mechanism of this invention adapted to a fixed vane/main flap. It is a modification of the single slotted flap with underneath support (FIGS. 1-3). The fixed vane/main flap configuration poses additional requirements on the flap deployment mechanism not encountered with the single slotted flap. The vane 54 must be carefully extracted from the cove 56 and in addition it must seal against the spoiler trailing edge when in the take-off position (FIG. 5). This type of motion is very difficult to accomplish with available linkage type flap mechanisms. A track type mechanism and a simple hinge are, at present, the only other ways to accomplish the required motion for a fixed vane/main flap.
In FIGS. 4-6 prime numbers have been used for the parts which correspond to the parts of the above described mechanism shown by FIGS. 1-3. In this embodiment, the support beam 28' includes an upper portion which is pivotally connected to a bracket 60 which is connected to the rear spar 13'. The upper portion of beam 28 also supports the rotary actuator 32' which, in this embodiment, is directly attached to the drive link 10'. The vane 54 is attached to flap 20' by a forwardly projecting connector strut 62.
FIGS. 7-9 show a double slotted embodiment. It incorporates a pair of folding truss actuation mechanisms of the type described for each flap. Each mechanism is connected to an end of its flap element. The mechanisms are enclosed entirely within the wing contour, as shown in FIG. 7.
This scheme incorporates an aft flap 64 for maximum flap effectiveness in the smallest possible package. The main flap mechanism arrangement is essentially the same as that described for the single slotted flap, with minor geometry changes. The flap carriage fitting is eliminated and the main flap 66 is attached directly to the drive link 10" and the swing link 22'. The swing link 22' has an extension 68 for actuating the aft flap 64 by means of a slave link 70. The aft flap mechanism is functionally like the main flap mechanism except that the aft support link 72 has an additional lug for supporting the aft flap support link 74. The primary difference between the main flap and aft flap linkage is that the aft flap is driven through the aft support link 72 rather than the forward support link. The aft flap also has a different relative position for take-off than the main flap, as shown in FIG. 8. There is no gap between main and aft flaps 66, 64 in the take-off position but a maximum gap 76 for landing, as shown in FIG. 9. The combined Fowler motion of main and aft flap in the take-off position is greater than that of the single slotted flap shown with underneath support.
In this embodiment, the rotary actuator 32', the first pivot joint 14", and the second pivot joint 27" are supported on a beam member 78 which is connected at its forward end to the wing rear spar 13". Even though swing link 22' includes the extension 68, the location at which it is pivotally attached to the main flap 66 may be considered to be the lower end of the swing link 22". In other words, swing link 22" is that portion of the member which interconnects pivot axes 31" and 34".
Referring to FIG. 9, the forward end of slave link 70 is pivotally attached to the lower end of extension 68 for pivotal movement about a pivot axis 80. The rear end of slave link 70 is pivotally attached to support link 72 for pivotal movement about a pivot axis 82. Link 72 is pivotally mounted onto a support portion of main flap 66 for pivotal movement about a pivot axis 84. Link 74 is pivotally attached at its lower end to the aft flap 64, for pivotal movement about an axis 86. At its opposite end it is pivotally attached to the support link 72 for pivotal movement about axis 88.
As has been shown, the folding truss mechanism of this invention is adaptable for a variety of trailing edge flap configurations. It has been shown and described in combination with single slotted flaps, main/aft double slotted flaps both with buried or underneath support schemes, and fixed vane/main double slotted flaps with underneath support. High Fowler motion for take-off position can be achieved with this type of flap mechanism (two to four times that of existing hinged flaps or track flaps). The mechanism can be designed to accommodate both scewed cylindrical or conical flap motion. All joints are simple pivots designed for minimum wear. The mechanism is designed so that aerodynamic loads on the flaps create stowing hinge moments, for a failsafe design. Hinge moments are relatively low compared with other, similar, concepts. The principle advantage of this flap support mechanism is its compact size, requiring small fairings for underneath flap support schemes and no fairings for the bearing support schemes. The payoff would be lower cruise drag for airplanes equipped with trailing edge flaps supported by a folding truss mechanism constructed in accordance with the present invention. | 4y
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BACKGROUND OF THE INVENTION
This invention relates to mechanism for first simultaneously cutting those lead ends of electrical components which have been thrust through a circuit board or the like, even though for different components lead spacings may vary, and then clinching the cut leads to secure them and effect their connection with circuitry.
In the prior art a number of cut-clinch mechanisms have been provided, some to accommodate manual component mounting and other intended for automatic component inserting apparatus. If the circuit board holding means is shiftable, one known semi-automatic arrangement includes a stationary cut-clinch device which may then incur both safety problems and operator fatigue by reason of the need for continually coping with moving elements. While prior clinching mechanisms have necessarily been shiftable toward and from their operating positions adjacent to the inserted leads to be cut-clinched in order to avoid interferring with previously mounted electrical components, the mechanisms have often been faulty in not assuring adequate component retention and also in endangering, or damaging, or interferring with previously clinched leads.
By way of reference, the following are a few of the lead cut-clinch arrangements disclosed in U.S. Pat. Nos. which may be of interest: 3,986,533 to Woodman, Jr.; 3,429,170 to Romeo; 3,852,865 to Ragard; 2,893,010 to Stuhre; and 3,414,024 to Anderson et al. The last-identified disclosure is notable in that it provides for simultaneously cutting variably spaced leads and then bending them in opposite directions by means of a sleeve and a rod both of which rotate about an axis. The Anderson et al arrangement will, accordingly, in such terms, superficially appear to have resemblance to the subject invention, but one major distinction amongst important others later mentioned is observed in that the patented arrangement is relatively unwieldy and functions to clinch leads only in the direction of a line interconnecting their lead-receiving holes. The latter mode of clinching is commonly found not to assure a sufficient stability for the body of the component on the opposite side of a circuit board from the clinching, any wobbling of the body tending to render the lead electrical connection unsatisfactory.
SUMMARY OF THE INVENTION
In view of the foregoing it is a primary object of this invention to provide an improved, versatile cut-clinch mechanism for operating on the inserted leads of electrical components, the mechanism to be conveniently capable of dealing with such leads when their spacing may vary.
Another object of the invention is to provide a novel cut-clinch device useful on inserted lead portions respectively protruding from holes in a circuit board when such holes are disposed variably apart and with different angular orientation.
A further object of the invention is to provide cut-clinch mechanism whereby, when a component body is mounted on one side of a support and variably spaced leads of the component project from the opposite side of the support, the clinching will cause the projecting end portions of the leads to extend in opposite directions transversely away from the body better to stabilize it on the support.
To these ends the invention comprises a stationary support for a pair of cutting-bending levers of different length rotatable thereon as later described. Vertical through-holes and slots in the levers are initially in alignment with a corresponding hole and slot in the support so that when upper surfaces of the levers contact a circuit board, for instance, the alignment enables reception of the leads of a component to be cut and clinched upon subsequent relative counter rotation of the levers. The lead wires are accordingly, predeterminedly shorn and then, if they extend from opposite ends of the so-called coaxial type component body, for instance, bent generally perpendicular to the body axis (or a line interconnecting the lead-receiving holes of the circuit board) to extend in opposite directions. Preferably, and as herein shown, the elements are pneumatically actuated, and power means is further provided to angularly orient the cut-clinch mechanism as a unit in order to accommodate different orientations of the components being processed.
The compact arrangement of parts lends itself to repositioning cyclically and hence for incorporation in component inserting apparatus which is automatic, semi-automatic, or to simply securing components which have been manually mounted.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other features of the invention will now be more particularly described in connection with an illustrative embodiment and with reference to the accompanying drawings thereof, in which:
FIG. 1 is a view in side elevation of a mechanism in raised position for cutting and clinching end portions of inserted leads, of variable spacing as indicated by solid and dot-dash lines, of an electrical component;
FIG. 2 is a plan view of the mechanism shown in FIG. 1;
FIG. 3 is a section taken on the line III--III in FIG. 2 and showing details of actuating mechanism when in raised operating position;
FIG. 4 is an enlarged detail view partly in section, of a portion of FIG. 3 showing an inserted lead (left one in FIG. 1) ready to be cut-clinched;
FIGS. 5 and 6 are views similar to FIG. 4 but showing the parts at subsequent stages; and
FIG. 7 is a bottom view of leads as clinched by the mechanism.
DESCRIPTION OF PREFERRED EMBODIMENT
A non-rotatable shear bar or shaft 10 is horizontally secured as by bolts or screws 11 (FIGS. 1 and 2) to a support 12 which is movable heightwise toward and from a circuit board B (FIGS. 1, 3 and 4) to the underside of which the variably spaced, inserted leads L,L of different illustative components C are to be clinched after being shorn as will be described later. It will be understood that usage of the invention is not limited to any particular type of shape of component body. Also, though not thus shown, the leads may be pre-crimped above the board B to provide stand-off mounting of the component bodies when so desired. The shaft 10 is formed with a vertical radial through-hole 14 for receiving an inserted lead L (the left-hand one in FIG. 1) endwise, and is provided with an elongated axially aligned through-slot 16 (FIG. 2) for receiving the end of the other lead of a component C. Usually, though not necessarily, bodies of the components are midway between the U-formed leg portions of the leads.
A pair of lead cutting and clinching levers 18 and 20 (FIGS. 1-4), the latter considerably longer than the lever 18, is pivotally carried on the shaft 10 for counter-rotation thereon during operation. Although the shaft 10 is herein preferably largely cylindrical to provide axially spaced bearing surfaces for the levers 18, 20, it will be appreciated that the shaft could optionally be a shear bar of other cross section than cylindrical and still mount the levers for cooperative shearing of the leads prior to bending thereof by the levers; an elongated cutting edge could also be provided in the member 20 without necessarily providing a through-slot therein. The lever 18 is formed with a short through-slot or radial hole 22 initially aligned with the shaft hole 14, and an axially elongated through-slot 24 in the lever 20 is initially aligned with the shaft slot 16. This is to say the levers 18 and 20, when first raised for operation and supportive contact with the board B adjacent to the locality thereof from which the leads L protrude to be cut-clinched, have the hole 22 and the slot 24 (FIG. 2) respectively in alignment with the shaft hole 14 and shaft slot 16. It will be apparent that the component C may then be installed as shown in FIG. 1 with its formed left-hand lead projecting through the board B, the hole 22 in the lever 18, and into the shaft hole 14, and its formed right-hand lead extending, according to its variable spacing from the inserted left lead, through the board B, the slot 24, and into the shaft slot 16. The upper or operating positions of the levers 18 and 20 are shown in FIGS. 3-5 and their subsequent angular inactive positions (indicated by dash lines in FIG. 3) are established by return springs 26 (FIG. 2) each interconnected to an outer end of the respective levers and the support 12.
Referring to the sequential views (FIGS. 4-6), the cut-clinch unit operation will be described with reference to that lead L inserted through the initially aligned holes 14 and 22, it being understood that a simultaneously similar operation is being executed on the other lead L accommodated by slots 16 and 24. Upper lead-wiping edges defining the hole 22 (and the slot 24) are rounded to define an enlarged mouth portion, and the lower or inner peripheral edge 28 of the hole (and of the slot) is not rounded but serves, in cooperation with the upper periphery of the hole 14, to shear off an excess lead end portion P (FIG. 5) when the lever 18 is actuated counterclockwise. The portion P falls through the hole 14 and exists via the lower end of the hole 22 to an out of the way position. Meanwhile the further rotation of the lever 18 causes the shorn lead to be bent and wiped against the underside of the board B by the rounded, radially outer edge of the hole 22 and by the adjacent outer, rounded surface of the lever 18 to position the lead transversely of a line interconnecting the lead receiving holes of the board as shown in FIGS. 6 and 7. In the case of coaxial lead type components having cylindrical bodies C as shown, ends of the leads, when clinched, accordingly oppositely extend substantially at right angles to axes of the bodies.
Mechanism for actuating the levers 18 and 20 as aforesaid will now be described largely with reference to FIG. 3. The support 12 is secured as by bolts 30 to a cylinder 32 movable heightwise between limits to position the levers between their lower inoperative position and upper actual or near board-contacting position. For raising the cut-clinch unit bodily, pressure fluid, preferably air, is admitted via a port 34 to a cylindrical chamber 36 beneath the cylinder 32, the chamber 36 being formed in a rotatable housing 38 wherein the lower end of the cylinder 32 functions as a piston. FIG. 3 illustrates the cylinder 32 in its raised position, dash lines also showing its lower or inoperative position wherein adequate clearance is afforded to enable relative shifting of the board B and the cut-clinch mechanism between successive operations. FIG. 3 also illustrates that fluid under pressure, for instance air, is admitted through an axial bore 40 in a piston 42 to a chamber 44 within the cylinder 32 thus to elevate the piston 42 from its dash-line position to its upper or solid line position. Such raising of the piston 42, effected after the cut-clinch levers 18,20 have received the depending lead portions L as shown in FIGS. 1 and 4, causes actuating rods 46,48 respectively to abut the levers and displace them counter-rotatively about the shaft 10 with the results as described with reference to FIGS. 5 and 6.
After the cut-clinch operation, release of pressure in the chamber 44 enables potential energy of a return spring 50 confined between a collar 52 fixed on the piston 42 and the housing 38 to lower the support 12. The springs 26, which had been put in tension during upward operating movement of the rods 46,48 are accordingly now permitted to rotate the levers 18 and 20 to their initial, hole-and-slot aligned positions in readiness for the next cycle of operations on a successive component.
It should be noted that a guide stud 54 (FIGS. 2,3) vertically secured to a flange of the cylinder 32 is slidable heightwise in a bore 56 formed in the housing 38. Accordingly, rotation of the housing by means next to be described will also turn the shaft 10 and the cut-clinch levers 18,20 together about a vertical axis to accommodate different angular orientation of the leads as inserted in the board B. Referring to FIGS. 1-3 again, the outer periphery of the housing 38 is formed with spline teeth 58 for meshing with teeth of a horizontal rack 60. The housing 38 is constrained axially and transversely by suitable bearings 62,64, within an outer stationary casing 66 accommodating linear travel of the rack. For thus moving the rack, it is coupled by a tie bar 68 (FIG. 2) to a piston rod 70 of a cylinder 72 adapted to be pressurized as by air. Consequently, movement of the rack linearly will produce angular movement to the desired extent of the cut-clinch mechanism as a unit about its vertical axis. A stop 74 may be releasably positioned along the rack as by a set screw 76 to limit rack travel and hence determine preset two selected angular positions of the cut-clinch mechanism. Dash positions of the stop 74 in FIG. 1 indicate 45° stop increments. Overtravel of the rack linearly may be prevented by provision of a limit stop not shown but projecting from the rack at its end opposite to the tie bar 68. For convenience in the illustrative embodiment this axis is preferably aligned with the lead receiving holes 14 and 22 and hence the center of one of the two preformed lead-receiving holes of the board B, but it may, in some instances, be otherwise aligned if desired without departing from the scope of this invention.
Briefly to review operation of the cut-clinch mechanism it will be assumed the formed, but unclinched leads L,L of whatever center spacing range (as provided for by extension of the aligned slots 16 and 24 from the aligned openings 14 and 22) have been inserted either manually or by other mechanism and project downwardly from the board B. Suitable supporting means (not shown) for the cut-clinch mechanism, either an automatic X-Y positioning table or a manually shiftable carrier, for instance, will then align the hole 14 with one projecting lead end L and orient the slot 16 of the shaft 10 with respect to the other lead L. Fluid pressure is then admitted through the port 34 to the chamber 36 causing the raising of the cylinder 32 whereby upper surfaces of the pivotal levers 18 and 20 are brought into contact or near contact with the underside of the board B. Such elevation of the cut-clinch unit also lifts the support 12, the rods 46,48 and the piston 42 thereby causing the leads L,L to be received endwise in the aligned holes and slots as shown in FIGS. 3 and 4. As is customary in the art, a downward pressure on the component leads above the board is preferably maintained (by means now herein shown) to prevent upward movement of the board B and maintain heightwise position of the component during cutting and clinching.
Next, fluid under pressure is admitted through the bore 40 to raise the piston 42 and hence cause the rods 46,48 to pivot the levers 18,20 in opposite directions about the axis of the shaft 10. This produces the cutting of both leads as above described and finally, as shown in FIGS. 6 and 7, bends and wipes the lead ends against the circuit board. These lead ends then extend in opposite directions and transversely away from a line interconnecting their board holes thereby insuring that the body of the component C on the opposite side of the board B will be secured in stable condition and prevented from tilting or working loose.
If the orientation of the components C to be successively inserted, cut, and clinched as described changes, the cut-clinch unit will be suitably rotated as required by operation of the cylinder 72 and its rack 60, return rotation of the unit to a fixed and known orientation being determined by a return spring (not shown) in the cylinder 72 or as by having the cylinder dual acting in response to fluid pressure admitted into either of its ends. | 4y
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BACKGROUND AND SUMMARY OF THE INVENTION
[0001] The present invention pertains generally to structural members and, more particularly, to a vehicle structure having an integral node.
[0002] In the field of motor vehicle design, it is highly desirable to construct a modular vehicle including a subframe adaptable for use with a variety of aesthetically pleasing outer panels. Additionally, the use of extruded tubular sections within the construct of the subframe greatly enhances the strength and durability of the frame without drastically increasing the weight and cost.
[0003] Unfortunately, many manufacturers have had difficulty reliably interconnecting individual tubular frame components to form a dimensionally correct and structurally robust vehicle frame. Accordingly, some manufacturers have implemented separate connectors, called nodes, to facilitate the joining process. The separate nodes are typically aluminum alloy castings having a plurality of apertures for receipt of tubular frame components. Due to the relative difficulty of welding aluminum alloys, cast nodes are especially prevalent in joints structurally interconnecting stamped or extruded aluminum components. As would be expected, the use of separate nodes is both costly and time consuming. Therefore, a need in the relevant art exists for an apparatus and method for interconnecting structural members.
[0004] Accordingly, it is an object of the present invention to provide an improved vehicle body construction exhibiting the advantages of a tubular construction without the need for separate connectors such as cast nodes.
[0005] It is another object of the present invention to provide a structural component including an integrally hydroformed node for use in a vehicle structure having improved strength and dimensional accuracy.
[0006] In accordance with the present invention, a fluid formed node is provided to connect structure in an automotive vehicle. Another aspect of the present invention includes a method of forming a structural interconnection including the steps of placing a first member, having an internal cavity in a die, pressurizing the internal cavity to form a node integral with and protruding from the first member, disposing the node within an aperture of a second member, and coupling the second member to the node.
[0007] The node of the present invention is advantageous over conventional construction in that the present invention provides an integrally formed attachment location economically created through the use of hydroforming. Additionally, structures incorporating the node of the present invention exhibit superior dimensional stability and structural integrity as compared to the structures previously described. Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] [0008]FIG. 1 is a perspective view of an automotive vehicle skeletal structure showing the preferred embodiment of a node of the present invention;
[0009] [0009]FIG. 2 is a fragmentary, exploded perspective view showing the preferred embodiment node;
[0010] [0010]FIG. 3 is a cross-sectional view showing a first embodiment of an extruded tubular member having an integral flange employed with the preferred embodiment node;
[0011] [0011]FIG. 4 is a cross-sectional view showing a second embodiment of an extruded tubular member having two integrally formed flanges employed with the preferred embodiment node;
[0012] [0012]FIG. 5 is a cross-sectional view, taken along line 5 - 5 , showing a third embodiment of an extrusion employed with the preferred embodiment node;
[0013] [0013]FIG. 6 is a cross-sectional view of a pair of hydroforming dies having the extrusion of FIG. 5 disposed within an internal cavity thereof;
[0014] [0014]FIG. 7 is a cross-sectional view of a second pair of hydroforming dies having a partially deformed extrusion disposed within an internal cavity thereof;
[0015] [0015]FIG. 8 is a cross-sectional view, taken along line 8 - 8 of FIG. 2, showing a first member employed with the preferred embodiment node;
[0016] [0016]FIG. 9 is a another fragmentary exploded perspective view showing the preferred embodiment of a structural interconnection;
[0017] [0017]FIG. 10 is a cross-sectional view, taken along line 10 - 10 of FIG. 2, showing a second member employed with the preferred embodiment node; and
[0018] [0018]FIG. 11 is a fragmentary perspective view showing the preferred embodiment structural interconnection.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] The following detailed description of the preferred embodiment is merely exemplary in nature and is no way intended to limit the invention, its application, or uses. For example, the apparatus and techniques disclosed herein may have utility in forming a wide variety of different structures including boats, bicycles, aircraft and railroad structures.
[0020] Referring to FIGS. 1 and 2, an exemplary structural interconnection 10 includes a hydroformed node 12 constructed in accordance with the teachings of the preferred embodiment of the present invention. Hydroformed node 12 is shown operatively associated with an exemplary vehicle frame 14 . It should be appreciated that one or more of the interconnections within vehicle frame 14 may include a hydroformed node such as node 12 and the specific interconnection discussed hereinafter is an example thereof.
[0021] Vehicle frame 14 includes a pair of side rail panel panels 16 extending substantially parallel to a longitudinal or fore-and-aft axis of the vehicle. A header panel 18 transversely spans vehicle frame 14 and interconnects each of the side rail panel panels 16 . Each of the panels 16 and 18 are preferably constructed from an aluminum alloy exhibiting high strength per unit weight.
[0022] With specific reference to FIG. 2, side rail panel 16 is preferably a generally hollow tubular shaped extrusion 20 having a first open end 22 , a second open end 24 with at least one of nodes 12 positioned therebetween. Side rail panel 16 also includes an outer surface 26 and an inner surface 28 defining a wall 30 . The cross sectional shape of the side rail panel 16 may be alternately constructed to suit a variety of different design applications. It is feasible to implement an extrusion having a first wall thickness for an application requiring moderate structural properties while another extrusion, having the same outer surface configuration as the first, may be formed to include a greater wall thickness and correspondingly superior structural properties. In this manner, it is possible to implement the lighter weight extrusion having a thinner wall in an otherwise rigidly framed vehicle such as a coupe while the second stiffer member is more suitable for a convertible automobile application. By maintaining a common outer surface profile, a single hydroforming die can create both coupe and convertible structural components as will be described hereinafter.
[0023] [0023]FIGS. 3 and 4 show two embodiments of pre-hydroformed extrusions. An exemplary first extrusion 31 , not incorporated within vehicle frame 12 , includes an inner surface 32 , an outer surface 33 and a flange 34 integrally formed with and radially protruding from the outer surface 33 . The single flange or first extrusion 31 is contemplated for use as a header panel with the flange 34 providing a mounting surface for a windshield. FIG. 4 shows a second extrusion 35 including a pair of flanges 36 radially extending from an outer surface 38 . The dual flange or second extrusion 35 of FIG. 4 provides mounting locations for other components such as vehicle body panels. It should be appreciated that the outer surface 38 is varied by simply modifying the geometry of the extrusion die (not shown). Accordingly, features such as the mounting flanges 34 and 36 are integrally formed with the tubular member during the extrusion process.
[0024] Referring to FIG. 5, the preferred embodiment of the side rail panel 16 is hydroformed from a third extrusion 40 including a generally constant thickness wall portion 42 and a reinforced thicker portion 44 . The reinforced wall portion 44 intrudes for approximately 30 to 45 degrees of the inner surface 28 of the side rail panel 16 obtaining a maximum thickness of approximately four milimeters. The generally constant thickness wall portion 42 is preferably one milimeter thick. It should be appreciated that the reinforced portion 44 acts as a sump or well of material when forming the node 12 such that a suitable minimum wall thickness is maintained throughout the finished hydroformed node. Because the reinforced portion is structurally necessary only at node locations, it is advantageous to maintain the generally constant wall thickness portion 42 for the majority of the cross section thereby reducing the overall weight of side rail panel 16 . Further weight reduction may be accomplished by selectively removing material located in the reinforced wall portions spaced apart from nodes 12 .
[0025] As mentioned earlier, node 12 of the present invention is integrally formed with side rail panel 16 through the use of internal fluid pressure, preferably by use of a hydroforming process. Hydroforming is essentially the process of deforming a tubular member to a desired complex tubular shape. To this end and with reference to FIG. 6, a tubular member such as extrusion 40 is placed between a first die 46 and a second die 48 having cavities 50 and 52 respectfully, which define the desired resultant shape of the side rail panel 16 . First end 22 and second end 24 of the tubular member are accessible through the dies and a seal (not shown) is connected to the ends of the tubular member. Pressurized fluid 54 , typically water, is then injected into the ends of the extrusion 40 at a pressure of approximately 100,000 PSI, thereby forcing wall 30 to outwardly expand and conform to the internal shape defined by the die cavities. Depending on the material chosen and the depth of draw required, a number of intermediate hydroforming dies may be required to assure uniform deformation of the side rail panel 16 without rupture. For example, and in reference to FIG. 7, a third die 56 and a fourth die 58 comprise a second hydroforming die set 60 for incrementally deforming the partially hydroformed extrusion 40 into the final desired shape. It should also be appreciated that, as mentioned earlier, the side rail panel 16 may be extruded to include other inner and outer contours prior to hydroforming to structurally enhance the side rail panel 16 and/or ease formation of the node 12 .
[0026] With reference to FIGS. 8 and 9, the completed hydroformed node 12 includes an end wall 62 and a side wall 64 extending substantially orthogonally from a longitudinal axis 66 of the side rail panel 16 . Side wall 64 is preferably formed at a small draft angle 68 typically ranging from three to seven degrees to facilitate removal of side rail panel 16 from the dies after hydroforming. Side wall 64 includes a generally convex portion 70 , and a generally concave portion 72 to form an asymmetric shape when viewed from the end wall 62 . The shape of side wall 64 functions to restrain header panel 18 from rotating once interconnected with node 12 . As best shown in FIG. 8, side wall 64 tapers, decreasing in thickness as the side wall approaches the end wall 62 where the section is at a minimum.
[0027] With reference to FIGS. 9 and 10, header panel 18 is also a generally cylindrical hollow extrusion having a first open end 74 and a second open end 76 . In the preferred embodiment each of the ends 74 and 76 are coupled to a node 12 of the present invention. For clarity, only one such interconnection will be described in detail. Specifically, first open end 74 includes an inner surface 77 and an outer surface 78 defining a wall 80 . The wall 80 includes a first recess 82 and a second recess 84 shaped to compliment the outer surface 26 of the side rail panel 16 . In addition, the first open end 74 includes a flared or swaged portion 86 for receipt of the hydroformed node 12 .
[0028] Because the preferred header panel 18 is a tubular member, the flared portion 86 may be created via a hydroforming process as well. In this manner, the flared portion 86 may be accurately formed to provide a slip or interference fit with the hydroformed node 12 as desired. Preferably, the inner surface 77 of the flared portion 86 compliments the draft angle 68 formed by the side wall 64 of the node 12 such that the inner surface 77 is positioned adjacent the side wall 64 at assembly. It should also be appreciated that the tubular header panel 18 is merely exemplary and that a variety of mating components may be utilized including stampings and/or castings. Optimally, the stamping or casting would include a flared portion to compliment the draft angle of the hydroformed node 12 .
[0029] Reference should now be made to FIG. 11 wherein the structural interconnection 10 is completed by engaging node 12 of side rail panel 16 with flared portion 86 of header panel 18 . Header panel 18 is mechanically attached to side rail panel 16 to provide further structural benefit. It is envisioned that a variety of attachment methods may be utilized including welding, mechanical fasteners, including rivets or screws, and adhesives. The preferred embodiment incorporates a plurality of rivets 88 extending through apertures (not shown) formed in the flared portion 86 of the header panel 18 and the side wall 64 of the hydroformed node 12 . The apertures may be created during the hydroforming process or added subsequently by processes such as drilling, stamping or laser cutting.
[0030] Therefore, it should be appreciated that the configuration and operation of the structural interconnection including a hydroformed node provides manufacturing and operational advantages over the prior art. Specifically, the hydroformed node 12 of the present invention provides an integrally formed attachment location economically created through the use of hydroforming.
[0031] The foregoing discussion discloses and describes merely exemplary embodiments of the present invention. While various materials have been disclosed, it should be appreciated that a variety of other materials can be employed. It is intended by the following claims to cover these and any other departures from the disclosed embodiments which fall within the true spirit of this invention. | 4y
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CROSS-REFERENCE TO RELATED APPLICATIONS, IF ANY
This application claims the benefit under 35 U.S.C. §119 (e) of provisional application Ser. No. 60/354,690, filed Feb. 6, 2002. Application Ser. No. 60/354,690 is hereby incorporated by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable
REFERENCE TO A MICROFICHE APPENDIX, IF ANY
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates, generally, to door hardware. More particularly, the invention relates to a door control cylinder. Most particularly, the invention relates to a releasable locking assembly for a door control cylinder.
2. Background Information
The state of the art includes various locking mechanisms for door control cylinders. This technology is believed to have significant limitations and shortcomings, including but not limited to that the mechanisms are difficult to operate, marginally effective and costly to manufacture.
Some examples of inventions concerning locking mechanisms for door control cylinders and the like for which patents have been granted include the following.
Stevens, in U.S. Pat. No. 4,286,325, describes a hold-open device for use with a conventional door closer. There is a shoe moving along a track and connected to the closer operating arm. A latch holds the shoe with the door open. The latch is attached to a frame near the track and may be moved away from latching engagement with the shoe by either forcibly closing the door or by deactivating the closer.
In U.S. Pat. No. 4,382,311, Watts discloses a pneumatic door-closer that includes a cylinder with a rod that extends upon opening the door. The rod has a series of transverse grooves and a clip encircling the rod. The clip has opposed ribs that can engage the grooves when the clip is rotated in one direction and disengage the grooves when the clip is rotated in the opposite direction to lock and unlock the clip on the rod.
Yang, in U.S. Pat. No. 4,545,322, describes a constant drag device the includes a cylinder with a stretchable tube-like sleeve surrounding and gripping an inner rod or tube. A coil spring surrounds the sleeve in position to resist movement on one end of the sleeve against the spring force. Moving the rod axially relative to the spring in a direction against the spring force on 5 the sleeve decreases the inner diameter of the sleeve to produce a drag on the inner member.
In U.S. Pat. No. 4,707,882, Watts discloses a pneumatic door-closer that includes a cylinder with a rod that extends upon opening the door. The rod has a series of transverse grooves and a clip encircling the rod. The clip has opposed ribs that can engage the grooves when the clip is rotated in one direction and disengage the grooves when the clip is rotated in the opposite direction to lock and unlock the clip on the rod.
Simmons, in U.S. Pat. No. 4,815,163, discloses a storm door locking apparatus that includes a clamp secured to the door cylinder with a slidable rod mounted thereto which is attached to a locking flange for engaging the cylinder rod to hold the door open. The user locks the door open by pushing a lever at the opposite end of the slidable rod.
In U.S. Pat. No. 4,920,609, Lin describes a pneumatic door closer that includes an actuator encircling the plunger rod and mounted in a plug. The actuator is biased by a spring and engages an annular groove in the plunger rod to hold the door open. The actuator is disengaged by opening the door further which causes a sleeve to disengage the actuator from the annular groove.
Guerin, in U.S. Pat. No. 5,048,150, describes a door holder that includes a piston unit with a separate rod attached by a housing to the piston unit and the door jamb. The rod has a cantable washer that is actuated by a pneumatic unit positioned on the floor for actuation by a user's foot.
In U.S. Pat. No. 5,529,148, O'Leary discloses an automatic brake and holding mechanism for sliding rods to maintain the rod at any desired position of extension or retraction with respect to an associated housing. A brake surrounds a rod with the brake confined within a barrel having a slot for holding the brake tab with the brake biased by a spring surrounding the rod. A release sleeve encircles the rod and has an enlarged end that can contact the brake. Also present is a latch that mounts to the exterior of the barrel, with a brake trip extending into the barrel through a slot therein.
Checkovich, in U.S. Pat. No. 5,592,780, describes a door position controlling apparatus. The apparatus includes a piston rod with a latch plate that is suspended by a flexing means to lock onto the rod and hold the door open. There is an electronic unit that imparts a force on a magnetized shaft to unlock the latch plate from the rod and allow the cylinder rod to retract and close the attached door.
In U.S. Pat. No. 5,630,248, Luca discloses a door closer with semi-automatic latching. The cylinder rod has a cantable washer confined to a short longitudinal space in the cylinder and riding on the rod. The washer is maintained in an essentially perpendicular orientation on the rod and a positional support is movable into the washer space to cant the washer, arrest the cylinder rod and hold the door open. To unlatch the door, the positionable support is withdrawn to avoid canting contact with the washer. The positional support may be a pin or a tab, with the washer having cut out portions.
Patterson, in U.S. Pat. No. 5,659,925, describes a door closer holding mechanism that includes a slidable stop on another rod that rides on the exterior of a cylinder with the stop dropping between the cylinder and door jamb to hold the door open. The stop has a lever for disengaging the device from between the cylinder and the door jamb.
U.S. Pat. No. 5,832,562 by Luca describes another door closer that includes a cylinder rod with a cantable washer confined to a short longitudinal space in the cylinder and riding on the rod. The washer is spring biased, and there is a complex arming and latching mechanism that includes a lever, a head, a spring and a trigger. The arming and latching of the mechanism is shown in FIGS. 4A-4G. Several other embodiments of the arming and latching mechanism, one with a slidable button as shown in FIGS. 5A-5E, and a toggle button as shown in FIGS. 6A-6E, are also disclosed.
In U.S. Pat. No. 5,842,255, Luca discloses another door closer that includes a cylinder rod with a complex tapered latching means confined to a short longitudinal space in the cylinder and riding on the rod. In one embodiment, a cantable washer interacts with a sliding eccentric support to lock the washer on the rod.
Green, in U.S. Pat. No. 6,202,253, describes a storm door cylinder lock that automatically locks the cylinder in an open position when the door is opened past 90 degrees. The cylinder includes an arm assembly, a cylindrical catch piece and a hard stop.
U.S. Pat. No. 6,317,922 by Kondratuk describes another door closer that includes a cylinder rod with a cantable washer having an angled portion, the washer confined to a short longitudinal space in the cylinder and riding on the rod. There is a base portion that forms the end of the cylinder and a cap that attaches to the base and encloses the washer. The base has a stepped surface that faces the cap, and the cap has positioning pegs to hold the washer in place. Rotating the cap in one direction causes the washer to engage the rod due to the stepped surface of the base, and rotating the cap in the opposite direction disengages the washer.
For this and other reasons, a need exists for the present invention. This invention provides a releasable locking assembly which is believed to fulfill the need and to constitute an improvement over the background technology.
All United States patents and patent applications, and all other published documents mentioned anywhere in this application are incorporated by reference in their entirety.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a releasable locking assembly apparatus/method for door control cylinders. Advantages and significant features of the invention include, but are not necessarily limited to, a releasable locking assembly that is simple to operate and install on existing door control cylinders. Further, the assembly of the present invention is uncomplicated and economical to manufacture.
The releasable locking assembly for selectively locking and unlocking a door control cylinder, having a spring biased rod member extending from an end thereof, includes a movable locking member encircling the cylinder rod member and retained within a first confining member secured to an end of the control cylinder with the rod member extending through the first confining member. The movable locking member is biased against an interior end of the first confining member opposite the control cylinder. A biased, linear actuating member parallels the rod member and traverses the first confining member end opposite the cylinder. The actuating member is movable to cant the locking member upon the rod member to secure the rod member in an extended condition. A second confining member is moveably secured to the first confining member and operatively connected to the biased, linear actuation member. Moving the second confining member toward the first confining member causes the biased actuation member to cant the locking member on the rod member to lock the rod member in an extended condition from the control cylinder. The locking member releases the rod member upon further extending the rod member from the control cylinder.
In a further embodiment of the invention, a releasable locking assembly for selectively locking and unlocking a door control cylinder, having a spring biased rod member extending from an end thereof, includes a movable locking member encircling the cylinder rod member and retained within a first cup member, having an open end and a closed end. The cup open end is secured to an end of the control cylinder with the rod member extending axially through the first cup member. The first cup member has a spacer member therein for maintaining a confined space between the first cup member closed end and the control cylinder end for the movable locking member. The movable locking member is biased against an interior closed end of the first cup member opposite the control cylinder by a first rod-encircling spring member. A biased, linear actuating member parallels the rod member and traverses the first cup member end opposite the cylinder. The actuating member is free moving and retained within an offset aperture in the first cup member closed end opposite the control cylinder, with a biasing spring surrounding the actuation member exterior the first cup member. The actuating member moves to cant the locking member upon the rod member to secure the rod member in an extended condition. A second cup member has an open end and a closed end with a axial aperture therein. The second cup member open end is moveably secured about the first cup member and operatively connected to the biased, linear actuation member. Moving the second cup member toward the first cup member causes the biased actuation member to cant the locking member on the rod member to lock the rod member in an extended condition from the control cylinder. The locking member releases the rod member upon further extending the rod member from the control cylinder.
The features, benefits and objects of this invention will become clear to those skilled in the art by reference to the following description, claims, and seven drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross sectional view of one embodiment of the releasable locking assembly of the present invention installed on a door control cylinder.
FIG. 2 is a partial cross sectional view of another embodiment of the releasable locking assembly of the present invention installed on a door control cylinder.
FIG. 3 a is a top view of the first cup member of the present invention.
FIG. 3 b is a cross sectional of the first cup member of the present invention.
FIG. 4 is a perspective view of one embodiment of the releasable locking assembly of the present invention, which is partially installed on a door control cylinder.
FIG. 5 is a perspective view of one embodiment of the releasable locking assembly of the present invention, which is partially installed on a door control cylinder.
FIG. 6 is an open end view of the first cup member of one embodiment of the present invention.
FIG. 7 is an open end view of the second cup member of one embodiment of the present invention.
FIG. 8 is a partial cross sectional view of yet another embodiment of the releasable locking assembly of the present invention installed on a door control cylinder.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Nomenclature
10 Releasable Locking Assembly
15 First Biasing Spring
20 Locking Flange Member
25 Positioning Tab
30 Locking Tab
35 First Cylindrical Cup Member
40 Closed End of First Cup Member
45 Central Aperture of First Cup Member Closed End
50 Positioning Tab Slot
55 Offset Aperture of First Cup Member Closed End
60 Second Biasing Spring Member
65 Second Cylindrical Cup Member
70 Closed End of Second Cup Member
75 Central Aperture of Second Cup Member Closed End
80 Retaining Rim Portion of Second Cup Member
85 Release Tab Actuating Member
90 Spacer Member
95 Peg Member
C Door Control Cylinder
F 1 First Fastener
R Cylinder Rod
F 2 Rod Fastener End
Construction
It is common practice to employ door control cylinders, particularly for storm doors. The control device consists of a cylinder C having a rod R that moveably extends from one end of the cylinder C. The end of the cylinder opposite the rod R contains a fastener F 1 that is secured to the door jamb, while the rod R has a fastener end F 2 that is secured approximately at the center line of the door. As the door opens, the rod R extends from the cylinder C and prevents the door from swinging open too far. Additionally, the cylinder C provides for a slow return of the rod R into the cylinder C when the door is released, thereby preventing the storm door from slamming. Various releasable locking mechanisms have been developed to lock the cylinder rod R in an extended condition to hold the storm door open. The mechanism is unlocked to allow the door to close on its own. The present invention is an improved releasable locking assembly for such a door control cylinder device.
Referring now to FIGS. 1-8, several embodiments of the releasable locking assembly 10 are shown. The assembly 10 is designed to be installed on a door control cylinder C and provide facile locking and unlocking of the cylinder rod R at any extended position. Referring to FIG. 1, the assembly 10 includes a first biasing spring member 15 that encircles the rod R adjacent the point where the rod R extends from the control cylinder C. A planar locking flange member 20 , having a central aperture, fits onto the rod R beyond the spring member 15 . The flange member 20 has a central aperture larger than the rod diameter to allow the flange member 20 to turn slightly from perpendicular and lock on the rod R. The flange member 20 has a positioning tab 25 set at a right angle to the planar flange member 20 and a locking tab 30 opposite the positioning tab 25 . The positioning tab 25 is oriented toward the control cylinder C, when the flange member 20 is installed on the rod R.
A first cylindrical cup member 35 has an axial central aperture 45 in the closed end 40 that accepts the rod R, with the open end of the cup member 35 fitting snugly over the end of the control cylinder C, as illustrated in FIGS. 1, 2 and 8 . Inside the first cup member 35 is a positioning tab slot 50 into which fits the positioning tab 25 of the locking flange member 20 . The tab slot 50 extends from the first cup member closed end 40 only a portion of the distance to the cup open end, thereby providing space for the locking flange member 20 to pivot, even with the end of the control cylinder C tight against the tab slot 50 . Opposite the positioning tab slot 50 is an offset aperture 55 in the first cup closed end 40 , the function of which is described below.
A second cylindrical cup member 65 also has an axial central aperture 75 in the closed end 70 that accepts the rod R, with the open end of the cup member 65 fitting loosely over the first cylindrical cup member 35 secured to the end of the control cylinder C, as illustrated in FIGS. 1, 2 and 8 . The second cup member 65 has an inwardly protruding, retaining rim portion 80 that holds the second cup member 65 over the first cup member 35 , while allowing the outer cup member 65 to move axially thereon. The closed end 70 of the second cup member 65 is biased away from the first cup member 35 by a second biasing spring 60 . In one embodiment of the invention, shown in FIG. 2, the second biasing spring member 60 encircles the rod R. In this embodiment, a locking tab actuating member 85 protrudes from the closed end 70 and inside of the second cup member 65 . The locking tab actuating member 85 is linear and cylindrical in shape and extends through the offset aperture 55 of the first cup closed end 40 , parallel the rod R, and in register with the locking tab 30 , as seen in FIG. 2 .
In operation, the releasable locking assembly 10 is installed on a door control cylinder, as shown in FIGS. 4-7. The door is opened and the cylinder rod R extends to the required degree. The first biasing spring member 15 maintains the locking flange member 20 within the first cup member 35 , against the closed end thereof, in an orientation perpendicular to the rod R. The user then gently pushes the second cup member 65 toward the cylinder C. This action causes the actuating member 85 to move and contact the locking tab 30 , pivoting the locking flange member 20 away from perpendicular and locking the rod R from retracting into the control cylinder C, thereby holding the door open.
The user unlocks the rod R from the locking flange member 20 by opening the door slightly more. This small movement of the door and attached rod R takes pressure off the locking flange member 20 , allowing the biasing spring member 15 to return the locking flange member 20 to a perpendicular orientation relative to the rod R and thereby allows the rod R to retract within the control cylinder C, allowing the door to close in a controlled manner.
In an alternative embodiment of the invention, the release tab actuation member 85 is free floating in the offset aperture 55 of the first cup closed end 40 . In this embodiment, shown in FIGS. 1 and 4 - 8 , the biasing spring 60 encircles the actuation member 85 that has enlarged ends to retain the actuation member 85 in the first cup member offset aperture 55 and maintain the biasing spring 60 there around. In this embodiment of the invention, the actuation member 85 also contacts and actuates the locking flange member 20 by the user pushing on the second cap member 65 , as described above.
Referring now to FIG. 8, another alternative embodiment of the releasable locking assembly 10 is shown. Those elements common with the elements of FIGS. 1 and 2 are designated with the same number. In this embodiment, the locking flange member 20 comprises a round, flat washer encircling the rod R and biased by the first biasing spring 15 . The flange member 20 has a central aperture larger than the rod diameter to allow the flange member 20 to turn slightly from perpendicular and lock on the rod R. Since the locking flange member 20 has no positioning tab 25 , the positioning tab slot 50 within the first cap member 35 is replaced by a spacer member 90 , which provides space for the locking flange member 20 to pivot, even with the end of the control cylinder C tight against the spacer member 90 . The offset aperture 55 in the first cup member end 40 contains the spring biased release actuating member 85 , as described above. In addition, a peg member 95 protrudes from the inside of the first cup member end 40 opposite the offset aperture 55 . The peg member 95 serves as a fulcrum for locking the flange member 20 onto the rod R by the user gently pushing the second cup member 65 toward the cylinder C, as described above. Likewise, the flange member 20 is unlocked from the rod R by opening the door slightly more, as described above. The biased actuating member 85 and the peg member 95 cooperate to maintain the locking member 20 in a movable condition, perpendicular to the rod R, until the second cup member 65 moves toward the control cylinder C to cant the locking member 20 on the rod R to lock it in place.
The descriptions above and the accompanying materials should be interpreted in the illustrative and not the limited sense. While the invention has been disclosed in connection with the preferred embodiment or embodiments thereof, it should be understood that there may be other embodiments which fall within the scope of the invention. | 4y
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PRIORITY INFORMATION
[0001] This application claims priority to Japanese Patent Application No. 2007-159189 filed on Jun. 15, 2007, which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] (a) Field of the Invention
[0003] The present invention relates to a touch switch for controlling accessory equipment of a vehicle according to a change in electrostatic capacitance caused when touched by a user.
[0004] (b) Description of the Prior Art(s)
[0005] Generally, an inner-door panel of a vehicle has a door pocket in which items such as maps or the like are stored by a vehicle occupant. It is, however, often difficult to retrieve a desired item from such a door pocket because usually light does not fully reach into the door pocket interior. As one attempt to provide a solution, door pockets provided with a lamp which can be turned on and off with a touch switch are sometimes provides. FIG. 8 shows the structure of such a door pocket according to a related technology.
[0006] In this example, the door pocket is comprised of mutually opposed side walls 10 A and 10 B, a main wall 10 C which is connected to the side walls 10 A and 10 B to form a U-shaped wall, and a bottom plate 10 D which makes the bottom of the door pocket. The door pocket is fitted to an interior panel 12 such that an opening on the opposite side of the main wall 10 C comes into contact with the door interior panel 12 . A lamp 14 is attached to the inside surface of the side wall 10 A of the door pocket. A touch plate 16 which configures a vehicle accessory touch switch is fixed to the inside surface of the main wall 10 C of the door pocket. When the touch plate 16 is touched by a human hand to turn on the vehicle accessory touch switch, the lamp 14 is supplied with power and turned on.
[0007] By configuring as described above, the lamp 14 can be turned on when the vehicle occupant inserts his or her hand into the door pocket and touches the touch plate 16 . Thus, the occupant can easily retrieve an item stored in the door pocket.
[0008] FIG. 9 shows a structure of a vehicle accessory touch switch 18 applied to a door pocket. The touch plate 16 is formed of a dielectric material such as a synthetic resin or the like. A sensor conductor plate 20 is bonded to one surface of the touch plate 16 and connected to a capacitance measurement/control unit 24 . The capacitance measurement/control unit 24 is connected to a ground conductor 26 having electric potential as reference.
[0009] A switch 28 is controlled to be in ON or OFF state by the capacitance measurement/control unit 24 . One of the terminals of the switch 28 is connected to a negative terminal of a battery 30 . The other terminal of the switch 28 is connected to one of terminals of the lamp 14 . The other terminal of the lamp 14 is connected to the positive terminal of the battery 30 .
[0010] The capacitance measurement/control unit 24 measures the electrostatic capacitance between the sensor conductor plate 20 and the ground conductor 26 (hereinafter, the electrostatic capacitance or capacity between the conductor plate and the ground conductor 26 is simply referred to as “the capacitance to ground”) and controls the switch 28 if the measured value has a change which exceeds a prescribed control judgment value.
[0011] According to the above-described configuration, the capacitance to ground of the sensor conductor plate 20 can be changed when a surface of the touch plate 16 , which is opposite to a surface to which the sensor conductor plate 20 is bonded, is touched with a human hand having electrostatic capacity with respect to the ground conductor 26 . Thus, lighting of the lamp 14 can be controlled by touching the touch plate 16 with a hand.
[0012] A related technology of the present invention is described in JP-A 2006-196395.
[0013] However, because the capacitance to ground of the sensor conductor plate 20 is variable depending on a change in humidity or the like of air around the vehicle accessory touch switch 18 , the vehicle accessory touch switch 18 may not function properly when the capacitance to ground is varied due to a change in atmospheric conditions. Also, a noise voltage may be induced in the conductor plate 20 by an unnecessary electromagnetic wave generated by other electric equipment, and an error occurs in the electrostatic capacitance measured by the capacitance measurement/control unit 24 , possibly causing a malfunction of the vehicle accessory touch switch 18 .
[0014] The present invention was achieved in view of the above-noted problems. Specifically, the present invention provides a touch switch for controlling accessory equipment of a vehicle that a malfunction which is caused by a factor due to changes in the environment such as a change of atmospheric conditions, receipt of an unrelated electromagnetic impulse, or the like can be avoided.
SUMMARY OF THE INVENTION
[0015] The present invention relates to a vehicle accessory touch switch, and may be configured to comprise a touch section having a sensor conductor plate which may be touched by a user, a capacitance measurement section which measures a change in electrostatic capacity of the sensor conductor plate to a ground conductor as a sensor conductor plate capacity change, and a control section which controls accessory equipment mounted on a vehicle according to comparison between the sensor conductor plate capacity change and a control judgment value, wherein the vehicle accessory touch switch controls the accessory equipment according to a user touch of the touch section, a sub-conductor plate is disposed independent of the sensor conductor plate, the capacitance measurement section measures a change in electrostatic capacity between the sub-conductor plate and the ground conductor as a sub-conductor plate capacity change, and the control section decides the control judgment value according to the sub-conductor plate capacity change measured by the capacitance measurement section.
[0016] According to the present invention, a vehicle accessory touch switch capable of avoiding a malfunction caused by an environmental change can be realized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is an exploded view of a vehicle accessory touch switch.
[0018] FIG. 2 is a diagram showing a vehicle accessory touch switch.
[0019] FIG. 3 is a flowchart showing a processing performed by a capacitance measurement/control unit.
[0020] FIG. 4 is an exploded view of a vehicle accessory touch switch with a sub-conductor plate disposed on a bottom plate of a door pocket.
[0021] FIG. 5 is a diagram showing a touch plate with a sub-conductor plate disposed in a vicinity of a lower end of a touch plate.
[0022] FIG. 6 is a diagram showing a touch plate having a sensor conductor plates disposed on a touch surface.
[0023] FIG. 7 is a diagram showing a vehicle accessory touch switch for controlling accessory equipment.
[0024] FIG. 8 is a diagram showing a door pocket in which a vehicle accessory touch switch is incorporated.
[0025] FIG. 9 is a diagram showing a structure of a general vehicle accessory touch switch.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0026] FIG. 1 shows an exploded view of a vehicle accessory touch switch 32 according to an embodiment of the invention which is incorporated into a door pocket. FIG. 2 shows a structure of the vehicle accessory touch switch 32 . Component parts corresponding to those of FIG. 8 and FIG. 9 are denoted by the same reference numerals, and their descriptions will not be repeated. The vehicle accessory touch switch 32 has a touch plate 16 provided with a sensor conductor plate 20 , and a sub-conductor plate 22 disposed on a side surface of a bottom plate 10 D to which a main wall 10 C is affixed.
[0027] The sensor conductor plate 20 and the sub-conductor plate 22 are connected with conductor wires 20 L and 22 L, respectively, and the conductor wires 20 L and 22 L are connected to a capacitance measurement/control unit 24 which is built into the side wall 10 B. The touch plate 16 is fixed to the inside surface of the main wall 10 C of the door pocket. The vehicle accessory touch switch 32 controls to turn on a lamp 14 disposed within the door pocket.
[0028] The structure and operation of the vehicle accessory touch switch 32 will be described with reference to FIG. 2 . The sensor conductor plate 20 is disposed on a surface opposite to the touch plate 16 having a touch surface 16 T which can be touched by a human hand. The sub-conductor plate 22 is disposed at a position where its capacitance to ground is not markedly changed even if the touch plate 16 is touched. Additionally, the sub-conductor plate 22 is disposed near the sensor conductor plate 20 . A distance between the sub-conductor plate 22 and the sensor conductor plate 20 is such a distance that a change (an environmental change in the vicinity of the vehicle accessory touch switch 32 ) due to an environmental change of the capacitance to ground of the sub-conductor plate 22 becomes equal to a change due to an environmental change of the capacitance to ground of the sensor conductor plate 20 .
[0029] The capacitance measurement/control unit 24 is connected to a ground conductor 26 . As the ground conductor 26 , the vehicle body may be suitably used.
[0030] A switch 28 is controlled by a control signal output by the capacitance measurement/control unit 24 . For the switch 28 , a semiconductor device circuit which is controlled by inputting a pulse signal indicating a high electric potential with respect to an electric potential of the ground conductor 26 for a prescribed time length is suitably used. For the switch 28 , a switch which is changed to an OFF state if it is in an ON state, and to an ON state if it is in an OFF state, each time the control signal is input can be used.
[0031] According to the structure of the vehicle accessory touch switch 32 shown in FIG. 1 and FIG. 2 , the sub-conductor plate 22 is disposed at a position where its capacitance to ground is not markedly changed even if the touch plate 16 is touched with a human hand. Therefore, the capacitance to ground of the sub-conductor plate 22 is changed by an environmental change which can be detected by detecting that the capacitance to ground of the sub-conductor plate 22 has changed.
[0032] The sub-conductor plate 22 is disposed near the sensor conductor plate 20 . Therefore, when the capacitance to ground of the sub-conductor plate 22 is changed, the capacitance to ground of the sensor conductor plate 20 is also changed by the environmental change which has changed the capacitance to ground of the sub-conductor plate 22 . Therefore, the change in the capacitance to ground of the sensor conductor plate 20 due to the environmental change can be detected by detecting that the capacitance to ground of the sub-conductor plate 22 has changed.
[0033] Accordingly, the vehicle accessory touch switch 32 according to this embodiment determines a control judgment value with respect to the capacitance to ground of the sensor conductor plate 20 based on the change in the capacitance to ground of the sub-conductor plate 22 and adjusts control sensitivity.
[0034] Processing performed by the vehicle accessory touch switch 32 when adjusting the control sensitivity will next described. FIG. 3 shows a flowchart of the processing. The capacitance measurement/control unit 24 measures a change in the capacitance to ground of the sub-conductor plate 22 as a sub-conductor plate capacity change ΔCB (S 1 ). The change in electrostatic capacity can be measured by, for example, measuring electrostatic capacity at intervals of a prescribed time Δt and determining a difference obtained by subtracting from the measured electrostatic capacity value obtained at a prescribed time the measured electrostatic capacity value which is obtained earlier by the time Δt than the time when the measured value is obtained. The electrostatic capacity is preferably measured by impedance measurement, measurement based on a charging time constant or the like.
[0035] The capacitance measurement/control unit 24 judges whether the absolute value of the sub-conductor plate capacity change ΔCB exceeds a prescribed threshold value T (S 2 ). If the absolute value of the sub-conductor plate capacity change ΔCB exceeds the threshold value T, a control judgment value D is set to a low-sensitivity judgment value DL (S 3 ). Meanwhile, if the absolute value of the sub-conductor plate capacity change ΔCB is equal to the threshold value T or less, the control judgment value D is set to a high-sensitivity judgment value DH (S 4 ). The low-sensitivity judgment value DL is determined to be a value larger than the high-sensitivity judgment value DH.
[0036] The capacitance measurement/control unit 24 processes in the same manner as that for measurement of the sub-conductor plate capacity change ΔCB to measure a change in the capacitance to ground of the sensor conductor plate 20 as a sensor conductor plate capacity change ΔCR (S 5 ).
[0037] The capacitance measurement/control unit 24 judges whether the absolute value of the sensor conductor plate capacity change ΔCR exceeds the control judgment value D set in the step S 4 or S 5 (S 6 ). If the absolute value of the sensor conductor plate capacity change ΔCR is not larger than the control judgment value D, the processing returns to the processing of the step S 1 . Meanwhile, if the absolute value of the sensor conductor plate capacity change ΔCR exceeds the control judgment value D, a control signal instructing the switching of the switch 28 is output (S 7 ). As the control signal, a pulse signal may be suitably used.
[0038] If the switch 28 is in an OFF state when the control signal is input, the switch 28 is changed to an ON state to turn on the lamp 14 . And, if the switch 28 is in the ON state, it is changed to the OFF state to turn off the lamp 14 .
[0039] By the above processing, the control judgment value D is set to a high-sensitivity judgment value DH if the environment around the vehicle accessory touch switch 32 is stable and the absolute value of the sensor conductor plate capacity change ΔCR is not larger than the threshold value T. Meanwhile, if the environment around the vehicle accessory touch switch 32 changes and the absolute value of the sensor conductor plate capacity change ΔCR exceeds the threshold value T, the control judgment value D is set to the low-sensitivity judgment value DL.
[0040] Here, the low-sensitivity judgment value DL is a value larger than the high-sensitivity judgment value DH. Therefore, if the environment around the vehicle accessory touch switch 32 changes, a value larger than the value which is set when the environment is stable is set as the control judgment value D. At step S 6 the control judgment value D indicates a level of change in the capacitance to ground of the sensor conductor plate 20 required for control of the switch 28 .
[0041] Therefore, if the environment around the vehicle accessory touch switch 32 changes, a change in the capacitance to ground of the sensor conductor plate 20 required for control of the switch 28 becomes larger than when the environment is stable. Thus, the capacitance to ground of the sensor conductor plate 20 is changed by the environmental change, and malfunctioning of the vehicle accessory touch switch 32 can be avoided.
[0042] The low-sensitivity judgment value DL is determined under a condition that it is less than the absolute value of the sensor conductor plate capacity change ΔCR at the time when a human hand touches the touch surface 16 T in addition to the condition that it is a value sufficient to avoid a malfunction. When the low-sensitivity judgment value DL is determined in this manner, the absolute value of the sensor conductor plate capacity change ΔCR exceeds the control judgment value D when the touch surface 16 T is touched by a human hand. Thus, a human touch will cause the capacitance measurement/control unit 24 (S 6 , S 7 ) to output the control signal, and the switch 28 can be controlled.
[0043] Meanwhile, it is preferable that the high-sensitivity judgment value DH is decided according to the operability of the vehicle accessory touch switch 32 . In other words, a distance between the human hand and the touch surface 16 T when the control signal is output in the step S 7 is set, and the high-sensitivity judgment value DH is determined such that the control signal is output when a human hand comes closer than the preset distance to the touch surface 16 T. It is preferable that the low-sensitivity judgment value DL and the high-sensitivity judgment value DH are decided through experimental evaluation, simulation, or the like.
[0044] Although an example in which the sub-conductor plate 22 is disposed on the side surface of the bottom plate 10 D was described above, the present invention may also be configured such that the sub-conductor plate 22 is disposed on the outside surface of the bottom plate 10 D of the door pocket as shown in FIG. 4 .
[0045] As shown in FIG. 5 , the sub-conductor plate 22 may be disposed near a lower end of the touch plate 16 . The sub-conductor plate 22 is disposed at a position separated as much as possible from the portion which is touched by a human hand. In the structure of FIG. 5 , the sensor conductor plate 20 and the sub-conductor plate 22 are disposed on the same flexible substrate 16 T and affixed to the touch plate 16 .
[0046] In addition, the touch plate 16 may be configured such that the sensor conductor plate 20 is provided on the touch surface 16 T as shown in FIG. 6 . The capacitance measurement/control unit 24 measures a change in the capacitance to ground of the sensor conductor plate 20 due to a contact or approach of the human hand to the sensor conductor plate 20 and controls the switch 28 according to the measured result. The sub-conductor plate 22 may be disposed on a surface opposite to the touch surface 16 T, a side surface of the bottom plate 10 D to which the main wall 10 C is bonded, an outer side surface of the bottom plate 10 D of the door pocket, or the like.
[0047] For the switch 28 provided on the vehicle accessory touch switch 32 , a switch which is changed from an OFF state to an ON state when a control signal is input and then changed to the OFF state after maintaining the ON state for a prescribed time period may be employed. When such a switch is used, the lamp 14 is lit for a prescribed time period after the touch plate 16 is touched by a human hand and goes off automatically. Thus, a person operating the lamp 14 can be freed from the burden of touching the touch plate 16 again in order to turn off the lamp 14 .
[0048] The vehicle accessory touch switch can be applied to the control of accessory equipment installed on the vehicle, such as automatic windows, an interior light, a radio, an air conditioner, and the like, in addition to the control of the switch 28 . An example vehicle accessory touch switch 38 for controlling such accessory equipment 36 is shown in FIG. 7 . In this figure, component parts corresponding to those of FIG. 2 are denoted by the same reference numerals, and their description will not be repeated. The capacitance measurement/control unit 24 controls the accessory equipment 36 in FIG. 7 . Generally, an accessory equipment control circuit is provided with a semiconductor device circuit which can control according to a pulse signal. Therefore, it can also control, for example, opening/closing of an automatic window, adjustment of an interior light, tuning of a radio, temperature setting of an air conditioner, and the like. | 4y
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BACKGROUND OF THE INVENTION
The present invention relates to a power-saving method of controlling registration in mobile communication systems such as, for example, code division multiple access (CDMA) cellular telephone systems.
The mobile terminals in a mobile communication system register their location with the system from time to time, so that the system can page them quickly when the need arises. For CDMA cellular telephone systems, Interim Standard IS-95 of the Telecommunication Industries Association specifies, among other forms of registration control, a timer-based scheme in which an idle mobile terminal sends a registration message to the system at regular intervals, which are designated by the system. The registration message contains information that the system can analyze to determine the location of the mobile terminal. The system stores the mobile terminal's location in a data base, which is updated as new registration messages arrive.
A problem with this registration control scheme is that while standing by to receive calls, a mobile terminal continues to send registration messages at the designated regular intervals, even if the mobile terminal is not actually moving. Since the registration messages are transmitted at comparatively high power, much power is dissipated in this way, causing unnecessary battery drain and shortening the time the mobile can continue operating in standby. System resources are also consumed in unnecessary data-base updates.
This problem is not limited to CDMA cellular telephone systems; it can occur in any type of mobile communication system that performs timer-based location registration.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to reduce the power dissipated by mobile terminals in performing location registration in a mobile communication system.
A further object is to reduce the usage of system resources in location registration updates.
The invented method of registration control in a mobile communication system comprises the steps of:
determining the velocity of a mobile terminal; and
adjusting the registration interval of the mobile terminal according to its velocity.
These steps can be performed by the system, by the mobile terminal, or by both. For example, the mobile terminal can determine its own velocity, and the system can adjust the registration interval in response to a request sent by the mobile terminal when the registration interval is inappropriate for the velocity.
The velocity of a mobile terminal can be determined in various ways: for example, from positional information provided by the base stations within range of the mobile terminal, or by sensing the Doppler shift in a carrier signal frequency.
The invention also provides a mobile terminal, a location registration apparatus, and a mobile communication system employing the invented method of registration control.
BRIEF DESCRIPTION OF THE DRAWINGS
In the attached drawings:
FIG. 1 is a block diagram of a mobile terminal;
FIG. 2 shows the external appearance of the mobile terminal in FIG. 1;
FIG. 3 is a block diagram of a location registration apparatus;
FIG. 4 is a sequence diagram illustrating the registration control procedure in a first embodiment of the invention;
FIG. 5 is a flowchart illustrating the calculation of distance moved in the first embodiment;
FIG. 6 is a flowchart illustrating the calculation of velocity in the first embodiment;
FIG. 7 is a flowchart illustrating the evaluation of the registration interval in the first embodiment;
FIG. 8 is a flowchart illustrating the adjustment of the registration interval in the first embodiment;
FIG. 9 is a cell map illustrating operations in a second embodiment of the invention; and
FIG. 10 is a sequence diagram illustrating the registration control procedure in a third embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the invention will be described with reference to the attached drawings, in which like parts are identified by like reference characters.
The invention will be exemplified within the context of a CDMA cellular telephone system comprising a plurality of base stations and a plurality of mobile terminals. Each base station serves a cell in the service area of the system, by communicating with mobile terminals located within the cell. The base stations are linked through one or more switching stations, each switching station communicating with a plurality of base stations. At least one switching station has a location registration apparatus that analyzes and registers the present locations of the mobile terminals on the basis of their registration messages.
In a first embodiment, each mobile terminal sends registration messages at intervals assigned by the location registration apparatus. In addition, each mobile terminal determines its own location, calculates its velocity as the rate of change in its location, decides whether the assigned registration interval is appropriate for the calculated velocity, and if the interval is not appropriate, sends the location registration apparatus a message requesting an adjustment of the registration interval. The location registration apparatus makes the requested adjustment.
Referring to FIG. 1, a mobile terminal in the mobile communication system comprises an antenna 1 , a receiver 2 , a decoder 3 , a transmitter 4 , an encoder 5 , a control unit 6 , a keypad 7 , a liquid crystal display or LCD 8 , a loudspeaker 9 , a light-emitting diode or LED 10 , a random-access memory or RAM 11 , and a read-only memory or ROM 12 , interconnected as shown. FIG. 2 shows the external appearance of the mobile terminal, indicating the antenna 1 , keypad 7 , LCD 8 , and LED 10 . Additional components, such as a microphone and batteries, have been omitted to simplify the drawings.
Briefly, the mobile terminal operates as follows. In the forward or receiving direction, a radio signal transmitted from a base station is received at the antenna 1 , amplified and demodulated by the receiver 2 , decoded by the decoder 3 , and supplied to the control unit 6 . In the reverse or transmitting direction, the encoder 5 encodes transmit data supplied by the control unit 6 , and the transmitter 4 modulates the coded data onto a carrier signal, which is transmitted from the antenna 1 to the base station. The keypad 7 is used for entering telephone numbers and other information, while the LCD 8 and LED 10 display telephone numbers and various status information.
The control unit 6 controls the mobile terminal by executing program modules stored in the ROM 12 , using the RAM 11 for additional data storage as necessary. The stored programs process data received from the decoder 3 and keypad 7 , provide data to the encoder 5 , and control the LCD 8 , loudspeaker 9 , and LED 10 . One of these program modules is a location registration module 12 =a.
FIG. 3 is a block diagram of the location registration apparatus. The location registration apparatus is linked by communication lines 13 to a plurality of base stations. The communication lines may be physical lines, as shown, or may comprise radiotelecommunication links with associated antennas, coders, and decoders. The location registration apparatus comprises a receiver 14 , a transmitter 15 , a control unit 16 , a RAM 17 , and a ROM 18 , interconnected as shown.
Information arriving from the base stations over the communication lines 13 is received by the receiver 14 and supplied to the control unit 16 . Information output from the control unit 16 is sent by the transmitter 15 to a designated base station over one of the communication lines 13 . The control unit 16 executes programs stored in the ROM 18 to process information from the receiver 14 , using the RAM 17 for data storage as required, and providing resulting information to the transmitter 15 . Thus the control unit 16 controls the location registration apparatus according to the programs stored in the ROM 18 .
A block diagram of a base station will be omitted. A base station operates as a relay station between the system and the mobile terminals, communicating with the mobile terminals on a plurality of wireless channels distinguished by different spreading codes. The channels used for location registration include access channels and paging channels. The information transmitted on a paging channel includes the exact latitude and longitude of the base station. Each base station also transmits a pilot signal on a pilot channel, and synchronization information on a synchronization channel.
Next, registration operations in the first embodiment of the invention will be described.
FIG. 4 illustrates the location registration procedure for one mobile terminal C that is within range of two base stations A and B. A similar procedure is followed when any number of mobile terminals are within range of any number of base stations. Processing particularly related to the present invention is indicated in boxes.
When the power of the mobile terminal C is switched on, the mobile terminal first attempts to receive pilot and synchronization signals transmitted from the base stations, a process referred to as system acquisition (step a). As part of this process, the mobile terminal measures the strength of the pilot signals. Following system acquisition, the mobile terminal sends a power-up registration message to either of the base stations on an access channel (step b). The power-up registration message includes a report of the measured power of the pilot signals. The base station that receives the registration message passes it to the location registration apparatus, which analyzes the reported pilot strengths to determine the location of the mobile terminal C, and registers the location of mobile terminal C in a data base in the RAM 17 (step c). The location registration apparatus also assigns a registration interval to mobile terminal C (step d), and decides which base station is best able to communicate with mobile terminal C. In the present example, base station A is selected as this base station; mobile terminal C is considered to reside in the cell of base station A. The system then uses base station A to send mobile terminal C an acknowledgment message specifying the assigned registration interval, and giving the latitude and longitude of base station A (step e). The same information is also provided to base station B, which is a candidate for becoming the next base station to communicate with mobile terminal C if mobile terminal C moves out of the cell of base station A.
The control unit 6 in mobile terminal C includes a timer for measuring the assigned registration interval. This timer is started when mobile terminal C receives the acknowledgment message (step f). When the timer times out (step g), mobile terminal C sends another registration message to base station A or, if the mobile terminal C cannot communicate with base station A, to base station B (step h). Between this registration message and the power-up registration message, mobile terminal C may have moved (step i). The location registration apparatus analyzes the new registration message to determine the new location of mobile terminal C, registers the new location (step j), and selects a new registration interval (step k). Mobile terminal C is informed of the new interval assignment in a new acknowledgment message (step 1 ).
From the latitude and longitude information received together with the acknowledgment messages in steps e and 1 , the mobile terminal C determines how far it has moved between the two interval assignments (step m). Dividing this distance by the time between the two interval assignments, mobile terminal C calculates its velocity (step n), and decides whether the assigned registration interval is appropriate for the calculated velocity (step o). If the assigned registration interval is inappropriate, mobile terminal C sends a request for an adjustment of the registration interval (step p).
Upon receiving this request, the location registration apparatus selects a new registration interval (step q) and returns another acknowledgment message notifying the mobile terminal C of the new registration interval (step r). The mobile terminal C sets its timer to the new registration interval, and starts the timer (step s). When the timer times out (step t), the mobile terminal C sends another registration message (step u).
Registration continues in this way at the intervals designated by the location registration apparatus, the mobile terminal C continuing to determine its own velocity and request that the registration interval be changed when necessary.
Next, steps d, k, m, n, o, and q will be described in more detail.
FIG. 5 illustrates the distance-calculation procedure followed in step m, for the case in which the mobile terminal C has moved from the cell of base station A to the cell of base station B. During the registration procedure, mobile terminal C receives the latitude and longitude of base station A (step 100 ) and the latitude and longitude of base station B (step 101 ) as described above. These two steps ( 100 and 101 ) may be performed in either order. The distance moved (D) is calculated (step 102 ) from the following equation:
D=|(ΔLAT 2 +ΔLONG 2 ) ½ /α|
where ΔLAT is the difference in latitude between base stations A and B, and ΔLONG is the difference in longitude between base stations A and B. The parameter α is a constant determined from, for example, the latitudes of the base stations and the relative strength with which their pilot signals are received at the mobile terminal.
Having calculated the distance moved, the mobile terminal obtains a time stamp giving the current time (step 103 ), and stores both the distance D and time stamp in the RAM 11 .
FIG. 6 illustrates the velocity-calculation procedure followed in step n. The distance moved (D) is read from the RAM 11 , together with the time stamps recorded at the beginning and end of the period of motion (step 200 ). The velocity (V) is then calculated from the following equation:
V=|D/Δtime|
where Δtime is the difference between the two time stamps. The calculated velocity is stored in the RAM 11 .
FIG. 7 illustrates the evaluation performed in step o. The calculated velocity (V) is read from the RAM 11 (step 300 ), and a pair of thresholds (L and U) are read from the ROM 12 (step 301 ). These thresholds depend on the assigned registration interval, and are stored in a table in the ROM 12 . The velocity (V) is compared with the thresholds (step 302 ). If the velocity (V) is less than the lower threshold (L), the mobile terminal determines that the registration interval is too short (step 303 ), and sends an adjustment request to the location registration apparatus, requesting that the registration interval be increased (step 304 ). If the velocity (V) is between the lower threshold (L) and upper threshold (U), the mobile terminal determines that the registration interval is appropriate (step 305 ). If the velocity (V) is greater than the upper threshold (U), the mobile terminal determines that the registration interval is too long (step 306 ), and sends an adjustment request to the location registration apparatus, requesting that the registration interval be decreased (step 307 ).
FIG. 8 shows the procedure followed by the location registration apparatus in deciding the registration interval. The registration interval currently assigned to the mobile terminal is read from the RAM 17 (step 400 ), and the control unit 16 determines whether the mobile terminal has sent an adjustment request for this interval (step 401 ). If the mobile terminal has requested an increase, the control unit 16 increases the registration interval by a predetermined amount, stores the increased interval in the RAM 17 (step 402 ), and notifies the mobile terminal of the increased interval (step 403 ). If the mobile terminal has not requested an adjustment, the control unit 16 sends the currently assigned interval to the mobile terminal again (step 404 ). If the mobile terminal has requested a decrease, the control unit 16 decreases the registration interval by a predetermined amount, stores the decreased interval in the RAM 17 (step 405 ), and notifies the mobile terminal of the decreased interval (step 406 ).
The procedures shown in FIGS. 5 to 8 can be modified in various ways. For example, a mobile terminal can determine its position as a weighted average of the latitudes and longitudes of the surrounding base stations, and store the determined position together with a time stamp in the RAM 11 . Velocity is then calculated as the distance between two such determined positions, divided by the difference between their time stamps.
The location registration apparatus can determine registration intervals on the basis of both system considerations such as processing loads, and adjustment requests made by mobile terminals.
Next, a second embodiment will be described. In the second embodiment, the mobile terminals adjust their own registration intervals.
Referring to FIG. 9, the base stations A, B, and D in the second embodiment serve cells with diameters of substantially ten kilometers (10 km).
A mobile terminal C is classified as moving at high speed if its velocity is at least fifty kilometers per hour (50 kph), at medium speed if its velocity is at least thirty kilometers per hour (30 kph) but less than fifty kilometers per hour, and at low speed if its velocity is at least ten kilometers per hour (10 kph) but less than thirty kilometers per hour. If the velocity is less than ten kilometers per hour, the mobile terminal is classified as stationary. The registration interval is one minute if the mobile terminal is moving at high speed, three minutes if at medium speed, five minutes if at low speed, and increases by stages, starting from ten minutes, if the mobile terminal is stationary. Mobile terminals determine their velocity from positional information (latitude and longitude) broadcast at intervals of, for example, one minute from the base stations. The mobile terminals receive all of these positional information broadcasts, and determine their velocities at intervals of one minute, using the equations given above.
The velocity ranges and intervals above are given only as one example. Many modifications are possible, provided the registration intervals satisfy system requirements.
If mobile terminal C is powered up while located at the position of the circled numeral ‘1’ in FIG. 9, its velocity is initially unknown, but in response to its first registration message, it is assigned to base station A and given an initial registration interval of, for example, three minutes. One minute later, and again two minutes later, mobile terminal C re-determines its position from the positional information supplied by base station A. As long as the mobile terminal C remains near position (1), it receives positional information only from base station A, so the result of the distance and velocity calculations described above is that mobile terminal C considers itself to be stationary. In its next registration message, mobile terminal C notifies the system of its stationary condition, so that the location registration apparatus will not remove the registered location of mobile terminal C from the RAM 17 even if subsequent registration messages arrive only intermittently.
Next, mobile terminal C successively increases its own registration interval from three minutes to five minutes, then ten minutes, then twenty minutes, thereby conserving battery power. This state continues as long as the mobile terminal C remains idle, not originating or receiving a call, and remains in the area covered only by base station A.
While still idle, if mobile terminal C moves from position (1) to position (2), it begins to receive positional information from both base station A and base station B, and can determine a non-zero velocity. If the mobile terminal C now calculates that it is moving at a medium speed, for example, it registers its location by sending registration messages at intervals of three minutes. If the mobile terminal C calculates that it is moving at a high speed, it registers its location by sending registration messages at intervals of one minute. When mobile terminal C begins to receive the pilot signal of base station B more strongly than the pilot signal of base station A, the location registration apparatus reassigns mobile terminal C from base station A to base station B.
If the mobile terminal C moves from position (2) to position (3), where it is within range only of base station B, then the control unit 6 in mobile terminal C begins lengthening the registration interval again, to conserve battery power.
In the second embodiment, the location registration apparatus can be simplified because the mobile terminals assume responsibility for adjusting their own registration intervals, and the location registration apparatus does not have to make decisions about registration intervals. This arrangement has the further advantage of reducing the amount of overhead communication between the mobile terminals and base stations.
In a variation of the second embodiment, the mobile terminals determine their velocity from the Doppler shift of the carrier frequency of the pilot signals transmitted by the base stations.
Next, a third embodiment will be described. In the third embodiment, the system determines the velocity of a mobile terminal from the Doppler shift of the carrier frequency of the signal transmitted by the mobile terminal.
Referring to FIG. 10, following system acquisition (step a′), mobile terminal C sends a power-up registration message (step b′) to base station A or B. The position of the mobile terminal C is registered in the location registration apparatus as described in the first embodiment (step c′). In addition, the Doppler shift of the carrier frequency of the signal from mobile terminal C is detected at base station A or B, or at both base stations, and the velocity of mobile terminal C is thereby determined (step d′). The location registration apparatus assigns a registration interval to mobile terminal C on the basis of the velocity, or on the basis of the velocity and other considerations, such as system processing loads (step e′). Mobile terminal C is notified of the assigned interval in an acknowledgment message (step f′). The timer at mobile terminal C is set to the assigned interval and started (step g′).
When the timer times out (step h′), mobile terminal C sends another registration message (step i′). The process of location registration (step J′), velocity determination (step k′), and interval assignment (step l′) is carried out again, and another acknowledgment message is sent (step m′), notifying mobile terminal C of a new registration interval. Mobile terminal C uses its timer to measure this interval (steps n′ and o′), then sends another registration message (step p′).
Subsequent operations continue in this way. When the system detects that a mobile terminal is stationary, or moving at a low velocity, it lengthens the registration interval to reduce the load on system resources and conserve battery power at the mobile terminal. When the system detects that a mobile terminal is moving rapidly, it assigns a short registration interval, so that the mobile terminal's location can be kept accurately up to date.
In a variation of the third embodiment, the location registration apparatus determines the location of a mobile terminal from the pilot signal measurements provided in its registration messages, determines the change in location from one registration message to the next, and determines the velocity of the mobile terminal by dividing the registration interval into the change in location.
The invention has been described in relation to a CDMA wireless mobile communication system, but is also applicable to other types of mobile communication systems employing time-interval-based registration control.
The control processes and other processes described above can be carried out by either software or hardware.
A mobile terminal can sense its velocity by use of an accelerometer, or by various other means not described above, without having to determine its position.
Those skilled in the art will recognize that further variations are possible within the scope claimed below. | 4y
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[0001] This application claims the benefit of the Patent Korean Application No. 10-2005-0019181, filed on Mar. 8, 2005, which is hereby incorporated by reference as if fully set forth herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an organic electroluminescence device, and more particularly, to red phosphorescene compounds and organic electroluminescence device using the same. Most particularly, the present invention relates to red phosphorescence being used as a dopant of a light emitting layer of an organic electroluminescence device, which is formed by serially depositing an anode, a hole injecting layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injecting layer, and a cathode.
[0004] 2. Discussion of the Related Art
[0005] Recently, as the size of display devices is becoming larger, the request for flat display devices that occupy lesser space is becoming more in demand. Such flat display devices include organic electroluminescence devices, which are also referred to as an organic light emitting diode (OLED). Technology of such organic electroluminescence devices is being developed at a vast rate and various prototypes have already been disclosed.
[0006] The organic electroluminescence device emits light when electric charge is injected into an organic layer, which is formed between an electron injecting electrode (cathode) and a hole injecting electrode (anode). More specifically, light is emitted when an electron and a hole form a pair and the newly created electron-hole pair decays. The organic electroluminescence device can be formed on a flexible transparent substrate such as plastic. The organic electro-luminescence device can also be driven under a voltage lower than the voltage required in a plasma display panel or an inorganic electroluminescence (EL) display (i.e., a voltage lower than or equal to 10V). The organic electroluminescence device is advantageous in that it consumes less energy as compared to other display devices and that it provides excellent color representation. Moreover, since the organic EL device can reproduce pictures by using three colors (i.e., green, blue, and red), the organic EL device is widely acknowledged as a next generation color display device that can reproduce vivid images.
[0007] The process of fabricating such organic electroluminescence (EL) device will be described as follows:
[0008] (1) An anode material is coated over a transparent substrate. Generally, indium tin oxide (ITO) is used as the anode material.
[0009] (2) A hole injecting layer (HIL) is deposited on the anode material. The hole injecting layer is formed of a copper phthalocyanine (CuPc) layer having a thickness of 10 nanometers (nm) to 30 nanometers (nm).
[0010] (3) A hole transport layer (HTL) is then deposited. The hole transport layer is mostly formed of 4,4′-bis[N-(1-naphtyl)-N-phenylamino]-biphenyl (NPB), which is treated with vacuum evaporation and then coated to have a thickness of 30 nanometers (nm) to 60 nanometers (nm).
[0011] (4) Thereafter, an organic light emitting layer is formed. At this point, a dopant may be added if required. In case of green emission, the organic light emitting layer is generally formed of tris(8-hydroxy-quinolate)aluminum (Alq 3 ) which is vacuum evaporated to have a thickness of 30 nanometers (nm) to 60 nanometers (nm). And, MQD(N-Methylquinacridone) is used as the dopant (or impurity).
[0012] (5) Either an electron transport layer (ETL) and an electron injecting layer (EIL) are sequentially formed on the organic emitting layer, or an electron injecting/transport layer is formed on the organic light emitting layer. In case of green emission, the Alq 3 of step (4) has excellent electron transport ability. Therefore, the electron injecting and transport layers are not necessarily required.
[0013] (6) Finally, a layer cathode is coated, and a protective layer is coated over the entire structure.
[0014] A light emitting device emitting (or representing) the colors of blue, green, and red, respectively, is decided in accordance with the method of forming the light emitting layer in the above-described structure. As the light emitting material, an exciton is formed by a recombination of an electron and a hole, which are injected from each of the electrodes. A singlet exciton emits fluorescent light, and a triplet exciton emits phosphorescene light. The singlet exciton emitting fluorescent light has a 25% probability of formation, whereas the triplet exciton emitting phosphorescene light has a 75% probability of formation. Therefore, the triplet exciton provides greater light emitting efficiency as compared to the singlet exciton. Among such phosphorescene materials, red phosphorescence material may have greater light emitting efficiency than fluorescent materials. And so, the red phosphorescene material is being researched and studied as an important factor for enhancing the efficiency of the organic electroluminescence device.
[0015] When using such phosphorescene materials, high light emitting efficiency, high color purity, and extended durability are required. Most particularly, when using red phosphorescene materials, the visibility decreases as the color purity increases (i.e., the X value of the CIE chromacity coordinates becomes larger), thereby causing difficulty in providing high light emitting efficiency. Accordingly, red phosphorescence material that can provide characteristics of excellent chromacity coordinates (CIE color purity of X=0.65 or more), enhanced light emitting efficiency, and extended durability needs to be developed.
SUMMARY OF THE INVENTION
[0016] Accordingly, the present invention is directed to red phosphorescence compounds and an organic electro-luminescence device using the same that substantially obviate one or more problems due to limitations and disadvantages of the related art.
[0017] An object of the present invention is to provide an organic electroluminescence device having high color purity, high brightness, and long durability by combining the compound shown in Formula 1, which is used as a dopant in a light emitting layer of the organic EL device.
[0018] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
[0019] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a red phosphorescence compound is indicated as Formula 1 below:
[0020] Herein each of R1, R2, R3, and R4 may be one of substituted or non-substituted C1 to C6 alkyl groups with disregard of one another. And, each of the C1 to c6 alkyl groups may be selected from a group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, and t-butyl.
[0021] Additionally,
may include 2,4-pentanedione
2,2,6,6,-tetra-methylheptane-3,5-dione
1,3-propanedione
1,3-butanedione
3,5-heptanedione
1,1,1-trifluoro-2,4-pentanedione
1,1,1,5,5,5-hexafluoro-2,4-pentanedione
and 2,2-dimethyl-3,5-hexanedione
[0022] Moveover,
may be any one of the following chemical formulas:
[0023] Furthermore, the Formula I may be any one of the following chemical formulas:
[0024] In another aspect of the present invention, in an organic electroluminescence device including an anode, a hole injecting layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injecting layer, and a cathode serially deposited on one another, the organic electroluminescence device may use any one of the above-described formulas as a dopant of the light emitting layer.
[0025] Herein, any one of Al and Zn metallic complexes and a carbazole derivative may be used as a host of the light emitting layer, and usage of the dopant may be within the range of 0.1 wt. % to 50 wt. %. The efficiency of the present invention may be provided when the amount of dopant used is within the above-described range. Furthermore, a ligand of each of the Al and Zn metallic complexes may include quinolyl, biphenyl, isoquinolyl, phenyl, methylquinolyl, dimethyl-quinolyl, dimethyl-isoquinolyl, and wherein the carbazole derivative may include CBP.
[0026] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention. In the drawings:
[0028] FIG. 1 illustrates a graph showing a decrease in visibility as color purity of an organic EL device increases (i.e., as the X value of chromacity coordinates becomes greater); and
[0029] FIG. 2 illustrates structural formula of NPB, copper (II) phthalocyanine (CuPc), (bpt) 2 Ir(acac), Alq 3 , BAlq, and CBP, which are compounds used in embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
[0031] A method of combining the red phosphorescence compound according to the present invention will now be described. An iridium (111)(2-(3-methylphenyl)-7-methyl-quinolinato-N,C 2 )(2,4-pentanedionate-0,0) compound, which is shown as A-2 among the red phosphorescene compounds used in the organic EL device according to the present invention.
COMBINATION EXAMPLE
1. Combination of 2-(3-methylphenyl)-6-methyl-quinoline
[0032]
[0033] 3-methyl-phenyl-boric acid (1.3 mmol), 2-chloro-6-methyl-quinoline (1 mmol), tetrakis (triphenyl phosphine) palladium(0) (0.05 mmol), and potassium carbonate (3 mmol) are dissolved in a two-neck round bottom flask containing THF (30 ml) and H 2 O (10 ml). The mixture is then stirred for 24 hours in a bath of 100 degrees Celsius (C). Subsequently, when reaction no longer occurs, the THF and toluene are discarded. The mixture is extracted by using dichloromethane and water, which is then treated with vacuum distillation. Then, after filtering the mixture with a silica gel column, a solvent is treated with vacuum distillation. Thereafter, by using dichloromethane and petroleum ether, the mixture is re-crystallized and filtered, thereby yielding solid 2-(3-methylphenyl)-6-methyl-quinoline.
2. Combination of Chloro-cross-linked Dimer Complex
[0034]
[0035] Iridium chloride (1 mmol) and 2-(3-methylphenyl)-6-methyl-quinoline (2.5 mmol) are mixed in a 3:1 liquid mixture (30 ml) of 2-ethoxyethanol and distilled water. Then, the mixture is refluxed for 24 hours. Thereafter, water is added so as to filter the solid form that is produced. Subsequently, the solid form is washed by using methanol and petroleum ether, thereby yielding the chloro-cross-linked dimer complex.
3. Combination of iridium (111)(2-(3-methylphenyl)-6-methyl-quinolinato-N,C 2 )(2,4-pentanedionate-0,0)
[0036]
[0037] A chloro-cross-linked dimer complex (1 mmol), 2,4-pentane dione (3 mmol), and Na 2 CO 3 (6 mmol) are mixed into 2-ethoxyethanol (30 ml) and refluxed for 24 hours. The refluxed mixture is then cooled at room temperature. Thereafter, distilled water is added to the cooled mixture, which is filtered so as to yield a solid form. Subsequently, the solid form is dissolved in dichloromethane, which is then filtered by using silica gel. Afterwards, the dichloromethane is treated with vacuum suction, and the solid form is washed by using methanol and petroleum ether, so as to obtain the chemical compound.
[0038] Hereinafter, examples of preferred embodiments will be given to describe the present invention. It will be apparent that the present invention is not limited only to the proposed embodiments.
Embodiments
1. First Embodiment
[0039] An ITO glass substrate is patterned to have a light emitting area of 3 mm×3 mm. Then, the patterned ITO glass substrate is washed. Subsequently, the substrate is mounted on a vacuum chamber. The standard pressure is set to 1×10 −6 torr. Thereafter, layers of organic matter are formed on the ITO substrate in the order of CuPC (200 Å), NPB (400 Å), BAlq+A-2(7%) (200 Å), Alq 3 (300 Å), LiF (5 Å), and Al (1000 Å).
[0040] At 0.9 mA, the brightness is equal to 1066 cd/m 2 (6.5 V). At this point, CIE x=0.646, y=0.351. Furthermore, the durability (half of the initial brightness) lasts for 5500 hours at 2000 cd/m 2 .
2. Second Embodiment
[0041] An ITO glass substrate is patterned to have a light emitting area of 3 mm×3 mm. Then, the patterned ITO glass substrate is washed. Subsequently, the substrate is mounted on a vacuum chamber. The standard pressure is set to 1×10 −6 torr. Thereafter, layers of organic matter are formed on the ITO substrate in the order of CuPC (200 Å), NPB (400 Å), BAlq+A-7(7%) (200 Å), Alq 3 (300 Å), LiF (5 Å), and Al (1000 Å).
[0042] At 0.9 mA, the brightness is equal to 1102 cd/m 2 (6.1 V). At this point, CIE x=0.645, y=0.352. Furthermore, the durability (half of the initial brightness) lasts for 5800 hours at 2000 cd/m 2 .
3. Third Embodiment
[0043] An ITO glass substrate is patterned to have a light emitting area of 3 mm×3 mm. Then, the patterned ITO glass substrate is washed. Subsequently, the substrate is mounted on a vacuum chamber. The standard pressure is set to 1×10 −6 torr. Thereafter, layers of organic matter are formed on the ITO substrate in the order of CuPC (200 Å), NPB (400 Å), BAlq+A-9(7%) (200 Å), Alq 3 (300 Å), LiF (5 Å), and Al (1000 Å).
[0044] At 0.9 mA, the brightness is equal to 949 cd/m 2 (5.3 V). At this point, CIE x=0.658, y=0.339. Furthermore, the durability (half of the initial brightness) lasts for 5000 hours at 2000 cd/m 2 .
4. Fourth Embodiment
[0045] An ITO glass substrate is patterned to have a light emitting area of 3 mm×3 mm. Then, the patterned ITO glass substrate is washed. Subsequently, the substrate is mounted on a vacuum chamber. The standard pressure is set to 1×10 −6 torr. Thereafter, layers of organic matter are formed on the ITO substrate in the order of CuPC (200 Å), NPB (400 Å), CBP+A-2(7%) (200 Å), a hole blocking layer(100 Å), Alq 3 (300 Å), LiF (5 Å), and Al (1000 Å).
[0046] When forming a hole blocking layer using BAlq, the brightness is equal to 986 cd/M 2 (6.7 V) at 0.9 mA. At this point, CIE x=0.641, y=0.357. Furthermore, the durability (half of the initial brightness) lasts for 4500 hours at 2000 cd/m 2 .
COMPARISON EXAMPLE
[0047] An ITO glass substrate is patterned to have a light emitting area of 3 mm×3 mm. Then, the patterned ITO glass substrate is washed. Subsequently, the substrate is mounted on a vacuum chamber. The standard pressure is set to 1×10 −6 torr. Thereafter, layers of organic matter are formed on the ITO substrate in the order of CuPC (200 Å), NPB (400 Å), BAlq+(btp) 2 Ir(acac)(7%) (200 Å), Alq 3 (300 Å), LiF (5 Å), and Al (1000 Å).
[0048] At 0.9 mA, the brightness is equal to 780 cd/m 2 (7.5 V). At this point, CIE x=0.659, y=0.329. Furthermore, the durability (half of the initial brightness) lasts for 2500 hours at 2000 cd/m 2 .
[0049] In accordance with the above-described embodiments and comparison example, the characteristics of efficiency, chromacity coordinates, brightness, and durability are shown in Table 1 below.
TABLE 1 Durability(h) Current Power ½ of Voltage Current Brightness Efficiency Efficiency CIE CIE initial Device (V) (mA) (cd/m 2 ) (cd/A) (1 m/W) (X) (Y) brightness First 6.5 0.9 1066 10.66 5.2 0.65 0.34 5500 Embodiment Second 6.1 0.9 1102 11.02 5.7 0.65 0.35 5800 Embodiment Third 5.3 0.9 949 9.49 5.6 0.66 0.34 5000 Embodiment Fourth 6.7 0.9 986 9.86 4.6 0.64 0.36 4500 Embodiment Comparison 7.5 0.9 780 7.8 3.3 0.66 0.33 2500 Example
[0050] As shown in Table 1, the device is operated with high efficiency at a low voltage even when the color purity is high (CIE(X)≧0.65). Furthermore, the current efficiency of the second embodiment has increased by 70% or more as compared to the comparison example. Additionally, the durability of the second embodiment has increased to twice that of the comparison example.
[0051] Table 2 below shows the characteristics of efficiency, chromacity coordinates, and brightness in accordance with the increase in voltage and electric current in the organic electroluminescence device according to the second embodiment of the present invention.
TABLE 2 Current Power Voltage Current Brightness Efficiency Efficiency CIE CIE (V) (A(mA/cm 2 ) (cd/m 2 ) (cd/A) (1 m/W) (X) (Y) 4.58 1.111 131.8 11.86 8.14 0.65 0.35 5.10 3.333 458.2 13.75 8.47 0.65 0.35 5.49 6.666 958.6 14.38 8.22 0.65 0.35 6.07 16.666 2336 14.02 7.26 0.65 0.35 6.52 33.333 4424 13.27 6.39 0.65 0.35 7.01 88.888 10160 11.43 5.12 0.64 0.35
[0052] As shown in Table 2, the second embodiment provides excellent efficiency, and the chromacity coordinates according to the driving voltage also maintains high color purity.
[0053] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. | 4y
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CROSS REFERENCE TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
REFERENCE TO MICROFICHE APPENDIX
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of lock guards in general, and in particular to a lock guard for the handle and lock on a tractor trailer to provide added safety to trailer doors by covering the padlock and latch mechanism.
2. Description of Related Art
As can be seen by reference to the following U.S. Pat. Nos. 3,976,318; 5,321,961; 5,426,959; and 5,447,710 the prior art is replete with myriad and diverse specialized lock guards.
While all of the aforementioned prior art constructions are more than adequate for the basic purpose and function for which they have been specifically designed, none of these patented devices have been specifically designed to provide a lock guard for the handle and lock on a tractor-trailer door.
The Krus reference, U.S. Pat. No. 3,976,318, discloses a burglar-proof cover with a hole in the center for key insertion, the cover to fit over a door lock and be secured to a door. A plate member is mounted to the doorjamb and prevents insertion of a tool between the cover and the jamb.
The Barberi reference, U.S. Pat. No. 5,321,961, discloses a security closure to cover a coin return slot and coin box of a vending machine. Access is provided to the coin insert and the coin return slots.
The Kies reference, U.S. Pat. No. 5,426,959, discloses a guard for enclosing the shackle of a padlock to prevent the shackle from being severed by bolt cutters.
The Stefanutti reference, U.S. Pat. No. 5,477,710, discloses a device for protecting a padlock that substantially covers the padlock.
As a consequence of the foregoing situation, there has existed a longstanding need among owners of tractor-trailers for a new type of lock guard which is specifically designed to cover the handle and lock on a tractor trailer door in a simple, straightforward, and effective manner to prevent unauthorized access to the locking mechanism and the provision of such a construction is a stated objected of the present invention.
BRIEF SUMMARY OF THE INVENTION
Briefly stated, the lock guard for tractor trailers that forms the basis of the present invention comprises a generally enlarged rectangular main housing unit provided with an interior center piece unit and an auxiliary housing unit which projects outwardly from one side of the main housing unit proximate the juncture of the center piece unit with the main housing unit.
As will be explained in greater detail further on in the specification, the main housing unit, the auxiliary housing unit and the center piece unit are all provided with apertures and/or recesses which are dimensioned to accommodate various portions of the tractor-trailer handle and lock so that the lock and selected portions of the handle are covered and the access to the lock is restricted by the presence of the lock guard.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
These and other attributes of the invention will become more clear upon a thorough study of the following description of the best mode for carrying out the invention, particularly when reviewed in conjunction with the drawings, wherein:
FIG. 1 is a rear perspective view of the lock guard for tractor trailers that forms the basis of the present invention; and
FIG. 2 is a front perspective view of the lock guard.
DETAILED DESCRIPTION OF THE INVENTION
As can be seen by reference to the drawings, and in particularly to FIG. 1, the lock guard for tractor trailers that forms the basis of the present invention is designated generally by the reference number (10). The lock guard (10) comprises in general, a main housing unit (11), an interior center piece unit (12), and an auxiliary housing unit (13). These units will now be described in seriatim fashion.
As can best be seen by reference to FIGS. 1 and 2, the main housing unit (11) comprises an enlarged generally rectangular open ended housing member (20) having a plurality of side panels (21), (22), (23), and (24), a face panel (25), wherein the side panel (22) of the housing member (20) is provided with an enlarged trapezoidal opening (26).
In addition, the face panel (25) of the housing member (20) is provided with an enlarged central aperture (27) and the top (21) and bottom (23) side panels are likewise provided with both aligned central apertures (28) and elongated generally rectangular recesses (29). The left side panel (24) of the housing member (20) is provided with a generally rectangular opening (30) which is in open communication with the interior of the housing member (20). The purpose and function of the aforementioned apertures, recesses, and opening will be explained in greater detail further on in the specification.
As can best be seen by reference to FIG. 1, the center piece unit (12) comprises a generally L-shaped center piece member (40) rigidly affixed to both the interior of the face panel (25) and the side panel (24). In addition, the foot portion (41) of the center piece member (40) is further provided with a discrete aperture (42) whose purpose and function will likewise be described in greater detail further on in the specification.
Still referring to FIG. 1, it can be seen that the auxiliary housing unit (13) comprises a generally rectangular extension member (60) having a rectangular opening (61) formed on one end which is in open communication with the interior of the main housing member (20) via the rectangular opening (30) formed in side panel (24) of the housing member 20). In addition, another opening (62) is formed on the bottom of the extension member.
As has been mentioned previously, the lock guard (10) that forms the basis of the present invention is designed to form a protective shield that fits over the existing trailer latch system of a tractor trailer to provide added safety to trailer doors.
In use, the user would slide the housing extension member (60) over the handle (101) of a trailer latch (100), wherein the handle would pass through the rectangular openings (61), (30), and the trapezoidal opening (26). The user would then close the handle (101) in a normal manner and place the foot portion (41) of the center piece member (40) between the top (102) and bottom (103) hasps in front of the handle (101). Then the user would insert a padlock (105) through the trapezoidal opening (26) in the side panel (22) of the housing in the member (20) and engage the padlock (105) through the hasps (102), (103) and the aperture (42) in the foot (41) of the center piece member (40), thereby securing the lock guard (10) over the handle (101) and hasps (102), (103) and locking the lock guard (10) in place.
In addition, the rectangular recesses (29) in the top (21) and bottom (23) side panels are dimensioned to permit clearance for the vertical locking bars (106), (107) located on the tractor trailer truck. The vertically aligned apertures (28) and the front aperture (27) are provided to permit the user to manipulate the padlock (105) into position.
In this manner, the lock guard (10) of this invention greatly reduces the probability of theft of tractor trailers by covering the padlock and latch mechanism thus increasing the difficulty of breaking or otherwise removing the lock.
Having thereby described the subject matter of the present invention, it should be apparent that many substitutions, modifications and variations of the invention are possible in light of the above teachings. It is therefore to be understood that the invention as taught and described herein is only to be limited to the extent of the breadth and scope of the appended claims. | 4y
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to metal working machinery and more particularly to machines for finishing the ends of metal tubing to precise dimensions and with any desired internal and/or external beveling. The preferred embodiment of the invention is a machine designed for quantity production of finished tubing, but many of its features will be found adaptable to portable tube finishing machines.
2. The Prior Art
Machines designed for the purposes of the present invention have employed various kinds of devices for holding a workpiece in a fixed relation with respect to metal working tools for shaping and finishing tube ends. The work holding devices employed have included both conventional chucks and other arrangements for gripping the exterior surfaces of workpieces. Examples of such devices are found in the Strout U.S. Pat. No. 3,228,268 and Saine U.S. Pat. No. 4,319,503.
When it is required in tube finishing that close dimensional tolerances be maintained, and especially where rates of production are important, such devices have not proved satisfactory, principally because of the difficulty of closing such chucks or the like without allowing some movement of the workpiece or, in the case of relatively thin-walled tubing, distorting the stock out of round.
SUMMARY OF THE INVENTION
The tube finishing machine of the present invention meets the objections described above by providing a machine in which the tubular workpiece is held in position during finishing by means inserted into the interior of the workpiece a sufficient distance to permit the desired finishing operations without interference between the holding means and the metal working tools. This arrangement makes it possible to automatically chuck and center over or undersized work pieces and to avoid distortion of thin walled stock out of round. Also, this makes it possible to maintain close tolerances in the product by abutting the rough cut tubes to be finished against a stock stop means accurately positioned adjacent the metal working tool. Optionally a second stock stop means selectively positionable along a rail extending from the housing carrying the metal working tool may be employed. The insertion and removal of workpieces in the machine is expedited by providing means for expanding the workholding means and advancing the tool into engagement with the workpiece in proper sequence and by providing for rapid release of the workpiece at the conclusion of each finishing operation.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a view in side elevation of a tube finishing machine embodying the present invention, with a workpiece shown in phantom in position for finishing.
FIG. 2 is a view in plan of a portion of the machine of FIG. 1 showing details of the workpiece positioning means.
FIG. 3 is a view in plan, partially in section, showing the interior of the housing and the positioning of a workpiece in relation to the metal working tooling.
FIG. 4 is detail view in front elevation of the rotatable face plate carrying the metalworking tooling and stock stops.
FIG. 5 is a view in side elevation and partly in section of the face plate of FIG. 4.
FIG. 6 is a detail view in side elevation of one of the stock stops showing the manner in which it is mounted on the face plate and the manner in which it engages a workpiece.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment of the tube finishing machine of the present invention, as shown in the accompanying drawings, has a base 10 (FIG. 1) supported by feet 11. Secured to the base 10, as by bolts 12, is a housing 15 closed at one end by a rear cover plate 16, at its opposite end by a front bearing plate 17, and at its side by a cover plate 18.
Means, including a draw bar 20 fixed at its rear end 21 to the rear cover plate 16, are provided for supporting an expansible collet assembly 22 in spaced relation to the front bearing plate 17, and a rotatably mounted face plate 23, in the space between the collet assembly 22 and the front bearing plate 17.
The collet assembly 22 (FIGS. 1, 2 and 3) comprises a frusto-conical taper arbor 25, axially slidable on the frontal portion of the draw bar 20; an assembly of, for example, six collet segments 26 presenting a cylindrical exterior and a interior cavity matching the taper of the arbor 25; and elastic O-rings encircling the segments 26 in grooves which serve to retain them in position.
The segments 26 are precisely restrained against endwise movement with respect to the draw bar 20, while remaining free to move radially, by a flanged collar 28 having a knurled head which is threaded on the front end portion of draw bar 20. This collar extends part way into notches 29 in segments 26, and a lock nut 30 threaded on the draw bar 20 is settable to limit forward movement of the collect assembly. This arrangement is such that forward movement of the taper arbor 25, toward collar 28, will cause outward radial movement of segments 26 to engage and grip the interior surface of a tubular workpiece A as shown in FIG. 3 and, when opposite movement of arbor 25 occurs, elastic O-rings will cause radial inward movement of the segments to release the workpiece. This arrangement allows free radial movement of the segments 26 to grip or release the stock while allowing minimal radial movement.
Pneumatic means are provided for expanding the collect assembly into gripping relationship with a workpiece and permitting its contraction to release the workpiece. For this purpose a sleeve 31 axially slidable on draw bar 20 is formed integrally with taper arbor 25 and carries at its rear end an air piston 32 which is reciprocable within a cylindrical cavity 33 in housing 15. The air piston 34 is constrained against rotational movement by pins 34 fixed in the piston 32 radially outwardly of its center and extending into cavities 34a in the housing 15.
The face plate 23 which, as will be described in more detail herinafter, carries metal working tools for finishing the ends of the workpiece A, is mounted for both rotational and axial movement with respect to draw bar 20. For this purpose the face plate 23 has formed integrally therewith a hub 35 which is both rotatable on and axially slidable with respect to sleeve 31 on oilite bearings 36 disposed between it and the sleeve.
Rotation of the face plate 23 is effected by a conventional electric motor diagrammatically indicated at 40 connected to a drive shaft 41 journalled in the housing 15 which carries at its forward end an input pinion 42 which is of sufficient width to mesh in axially displaced positions with a narrower drive gear 43 which is secured to the hub 35 of face plate 23 and therefore axially movable therewith. The drive gear 43 is urged toward its rearward position by spring means comprising compression springs 44 seated in recesses in gear 43 andin the front bearing plate 17 respectively; a bearing 45 being interposed between the spring means and the front bearing plate with respect to which the spring means is rotatable.
Means are provided for actuating sequentially, the mechanism for expanding the collet assembly into gripping relationship with a workpiece, and advancing the face plate to engage its tooling with the workpiece. For this purpose there is journalled in the housing 15 an actuating shaft 50 having a radial extension 51 (see also FIG. 1) provided at its upper end with a feed handle 52 to facilitate manual oscillation of shaft 50. Oscillatory movement of the feed handle 52 is limited by a pair of stop clamps 53 and 56 (see also FIG. 3) settable at any desired positions along an arcuate segment 54 integral with housing 15 and capable of being secured in position by lock screws 55.
Means are provided for actuating the mechanism for expanding the collect assembly into gripping engagement with a workpiece upon initiation of clockwise movement of the actuating shaft 50 from the position in which it is shown in the drawings. For this purpose there is secured to the housing 15 adjacent the shaft 50 a two-position air valve 57 of conventional construction such as the Model KSC-4212 manufactured by Versa Products Co., Inc of Paramus, N.J., which when its core 58 is is its normal position into which it is spring biased, admits air under pressure from a source connected at 59 into a passage 60 in the side wall of housing 15 and thence into the cavity 33 on the forward side of the piston 32, thus maintaining the piston 32, sleeve 31 and taper arbor 25 in their rearward, retracted positions permitting the collect assembly to be retracted out of engagement with a workpiece.
When the core 58 of the air valve 57 is moved into its second position, air is exhausted through the passage 60 and air under pressure from the source is admitted to a passage 61 and thence via passages 62, 63 (which is closed at its outer end by a plug) and 64 to the portion 65 of cavity 33 at the rear, or leftward, side of the piston 32. This effects forward movement of the piston and sleeve 31, expanding the collet assembly into gripping relationship with the interior of a workpiece. As air pressure builds up in the cavity following forward movement of the piston 32, air exiting through passage 67 actuates a conventional pressure operated electrical switch 68, which may be, for example, a reverse action switch manufactured by Furnas Electric Co. of Batavia, IL identified as Series B-715 69WR5. This starts the motor 40 and initiates rotation of face plate 23. Thereafter, when the core of the air valve 57 is returned to its first position, air is exhausted through passages 67, 64, 63, 62 and 61 and air under pressure from the source is admitted through passage 60, causing retraction of the piston 32 to its rearward position and opening of the motor switch 68.
The forward end of the core 58 of air valve 57 extends into a circular depression 58a in the side of the actuating shaft 50 so that upon the first clockwise movement of the shaft, the core 58 is cammed into its second position, causing the collet assembly to expand into gripping relationship with a workpiece.
The inner end of the actuating shaft 50 terminates in a pin 66 which is eccentric with repect to the axis of the shaft. This pin extends into the inner race of a ball bearing 67 the outer race of which bears against the hub of gear 43 which is secured to the hub of face plate 23 so that upon clockwise movement of the shaft 50, the face plate 23 is moved forwardly to bring the tooling carried by it against the end of the workpiece after the workpiece has been gripped by the expanded collet assembly.
As shown in FIGS. 3, 4, 5 and 6; the face plate 23 provides a base upon which a plurality of metal working tools may be adjustably mounted and brought into engagement with the end of a workpiece to finish it precisely to a desired length; to bevel its exterior margin; to bevel its interior margin; or for other purposes. A plurality of such operations can be performed simultaneously.
For this purpose the face plate 23 is provided with a plurality of slots 69 into which the base portions of tool blocks 70, 71 and 72 are fitted for sliding movement radially of the face plate. Adjustment of the tools along the slots is effected by rotation of feed screws 75 keyed to ears 76 on the face plate for rotation therein and mating with complementary threads in the tool blocks 70, 71 and 72. Following adjustment of the tool blocks, they are firmly retained in adjusted positions by locking blocks 77 held against the tool blocks by screws 78.
Radially spaced with respect to the center of face plate 23 are stock stops 80 and 81, shown in detail in FIG. 6, each of which comprises a head portion 82 and a shank portion 83 which fits and is slidable within a passage in the face plate 23 and is secured in position by a resilient retainer fitting within a groove in the shank 83.
As shown in FIGS. 1 and 2, there is secured to the under side of base 10, a stop scale rail 85 supported at its opposite end by a threaded post 86 on which the rail is vertically adjustable for leveling. A stock rest 87 having a removable semi cylindrical concave upper portion 88 is mounted for endwise sliding movement along the rail 85 to provide intermediate support for a workpiece, and this rest may be clamped at any desired position along the rail by a vise type clamp actuated by a handle 89.
Also mounted for sliding movement along the rail 85 is a gravity finger stop assembly 90 comprising a pair of split ring clamps 91 and 92 the opposite portions of which are joined by screws 93 and 94 by means of which they may be secured at any desired position along the rail 85. A sleeve 95 disposed between the clamps 91 and 92 journals a gravity finger stop 97 comprising an upwardly extending finger stop 98 and a counterweight 99 on its depending portion.
This arrangement is such that the counterweight 99 normally maintains the finger 98 in a vertical attitude in which it extends into the path along which a workpiece is inserted over the collet. During such positioning of a workpiece, however, it may be manually moved aside from that path.
Optionally, a scale may be placed in a groove 100 along the upper face of rail 85 to facilitate the positioning of stop 97 in conformity with the desired dimensioning of the workpieces to be finished.
OPERATION
In employing the machine of the present invention to finish the ends of tubing, a collet assembly 22 of the appropriate diameter first is placed on the free end of draw bar 20, then a section of tubing cut to the approximate length desired is placed on the stock rest 87 and moved endwise over the collet assembly into contact with the face of one of the stock stops 80, 81 depending upon the diameter of the tubing; the finger 98 being manually moved aside for this purpose.
The handle 52 is then moved slowly clockwise. This results in first expanding the collect assembly 22 to grip the interior of the tubing and, sequentially thereafter, in moving the face plate 23 which is now being rotated by the motor, toward the clamped end of the tubing; the stock stop or stops 80, 81 in contact with the tubing remaining fixed in position as the face plate advances. As the face plate advances further, its cutting tools 70, 71 and 72 are brought into contact with the tubing's end and the desired finish, as observed by the operator, is thus applied to that end. The forward handle stop 56 is then moved to a position against the handle and set by tightening screw 55, and the handle is returned to its home position against the rear stop 53 to cause retraction of the face plate 23 and contraction of the collet assembly to release the tubing.
The tubing is then reversed end for end and its unfinished end is placed over the collet assembly and in engagement with the stock stop or stops. At this point, optionally, the gravity finger stop assembly may be clamped in a position on the rail 85 in which the finger 98 engages the already finished end of tubing. Again, the handle 51 is moved clockwise to first expand the collet assembly into gripping relationship with the inside of the tubing and then finish the previously unfinished end of the tubing; the forward stop 53 insuring against removal of excess material and exactly controlling the length of the finished workpiece. When this has been accomplished, the handle is again returned to its home position against the rearward stop 53, thus releasing the finished tubing.
While the foregoing description and drawings constitute a disclosure of the presently preferred embodiment of the invention, it is understood that modifications will occur to those skilled in the art to which the invention relates and that therefore the invention is not to be considered as limit except as required by the prior art and by the spirit of the appended claims. | 4y
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FIELD
[0001] The invention relates to electromechanical locks.
BACKGROUND
[0002] Various types of electromechanical locks are replacing traditional mechanical locks. Electromechanical locks require an external supply of electric power, a battery inside the lock, a battery inside the key, or means for generating electric power within the lock making the lock user-powered. Electromechanical locks provide many benefits over traditional locks. They provide better security, and the control of keys or security tokens is easier.
[0003] In addition, most electromechanical locks and/or keys and tokens are programmable. It is possible to program the lock to accept different keys and decline others.
[0004] One problem associated with all kind of lock systems is the key or security token distribution. Keys and security tokens must be distributed to users. On the other hand, users may have several keys and security tokens at their disposal which may lead to burdensome handling of the keys and tokens.
BRIEF DESCRIPTION
[0005] According to an aspect of the present invention, there is provided an electromechanical lock comprising: an electronic circuitry for storing a challenge, providing a wireless interface for a communication device to read the challenge, receiving and storing a response from the communication device, and authenticating the response, and for issuing an open command provided that the authentication is successful, the circuitry being configured to receive wirelessly from the communication device operating power for communication with the communication device and to store the response, an actuator to receive the open command, and to set the lock in a mechanically openable state, a user interface configured to receive input from a user, and a generator configured to generate operating power from the input for the authenticating and actuator operations.
[0006] According to another aspect of the present invention, there is provided a method for operating an electromechanical lock, comprising: storing a challenge in an electronic circuitry; receiving wirelessly from a communication device operating power for providing a wireless interface for the communication device to read the challenge and receiving and storing a response from the communication device; and receiving with the user interface of the lock input from a user, generating from the input the operating power for authenticating the response; issuing an open command provided that the authentication is successful and setting the lock in a mechanically openable state in response to the open command.
[0007] According to yet another aspect of the present invention, there is provided a computer program product encoding a computer program of instructions for executing a computer process carrying out the steps of: storing a challenge in an electronic circuitry; receiving a Near Field Communication query from a communication device; providing a wireless interface providing an interface for a communication device to read the challenge using Near Field Communication; receiving a response from the communication device using Near Field Communication, storing and authenticating the response; and issuing an open command provided that the authentication is successful.
[0008] The invention has several advantages. The described electronic lock and key system and wireless solutions minimize energy consumption in a wireless lock, enabling self-powered lock solutions.
[0009] In an embodiment of the invention, an electronic wireless key is utilized for wirelessly opening an electronic wireless lock. The key is carried by a person as a part of his wireless communication device and it may be provided with a Near Field Communications (NFC) device.
[0010] Embodiments of the invention may be applied to electromechanical locks having an external power supply, a battery inside the lock or inside the key or user-powered electromechanical locks.
LIST OF DRAWINGS
[0011] Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which
[0012] FIG. 1A illustrates an embodiment of an electronic authentication system;
[0013] FIG. 1B illustrates an embodiment of a self-powered electronic locking system;
[0014] FIG. 2 illustrates an embodiment of a communication unit;
[0015] FIGS. 3A , 3 B and 3 C are flowcharts illustrating embodiments; and
[0016] FIGS. 4A , 4 B, and 4 C illustrate embodiments of an electronic locking system.
DESCRIPTION OF EMBODIMENTS
[0017] The following embodiments are exemplary. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations, this does not necessarily mean that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.
[0018] In an embodiment of the invention, an electronic key is utilized for wirelessly opening an electromechanical wireless lock. The key may be carried by a person as a part of his wireless communication device. FIG. 1A shows an embodiment of an electronic locking system. A user 105 is about to open a door 115 . The user has a communication device 106 .
[0019] The communication device 106 refers to a portable computing device. Such computing devices include wireless mobile communication devices operating with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: mobile phone, smartphone, personal digital assistant (PDA), handset. The communication device 106 may have a wireless network channel 104 connection to a wireless network 102 . The wireless connection channel 104 and the wireless network 102 may be implemented according to the GSM (Global System for Mobile Communications), WCDMA (Wideband Code Division Multiple Access), WLAN (Wireless Local Area Network) or any other suitable standard/non-standard wireless communication means.
[0020] In an embodiment, the communication device 106 comprises a Subscriber Identity Module (SIM) or a Universal Integrated Circuit Card (UICC). The SIM and the UICC are used in mobile communication systems to identify subscribers. Each communication device of a given system comprises such an identification. The SIM and the UICC comprise an integrated circuit capable of performing computations and storing data.
[0021] The communication device 106 is equipped with a short-range wireless communication unit configured to communicate with other respective short-range units upon detecting such a unit.
[0022] In an embodiment, short-range wireless communication is realised with a Near Field Communication (NEC) technique. NFC is a standardized wireless communication technique designed for data exchange between devices over short distances. A typical working distance is about 0 to 20 centimeters. NFC uses a given frequency (13.56 MHz). NFC transceivers may be active, semi-passive or passive.
[0023] Active transceivers comprise a power source which is used to power the transceiver components and the transmission. Passive transceivers comprise do not comprise a power supply. They receive the operating power wirelessly from a magnetic field generated by a nearby NFC transmission. Thus, they are active only when an active transceiver transmits within the coverage area of the transceiver. Passive transceivers do not consume power when they are in an idle state. Typically, passive transceivers are RFID (Radio-frequency identification) tags which comprise a memory circuit and a passive transmitter which is configured to respond to an NFC transmission query. Semi-passive transceivers comprise a power supply but the power supply is used to power a microchip of the transceiver but not to broadcast a signal. To transmit a semi-passive device needs to be powered by an active transceiver.
[0024] The door 115 comprises an electromechanical lock 116 . The lock comprises a lock interface 108 , a lock antenna 112 and a lock bolt 114 . The lock antenna 112 is connected to an electronic circuitry of the lock (not shown in FIG. 1A ). The circuitry comprises a short-range communication device. The device may be an NFC transceiver. In an embodiment, the NFC transceiver of the lock is a passive transceiver.
[0025] When the user approaches the door he wishes to open, he brings the communication device 106 close to the lock antenna 112 . The electronic circuitry of the lock is powered by the short-range transmission of the communication device and a transaction is initiated. The communication device reads an authentication challenge from the electronic circuitry of the lock. The communication device 106 computes a response and transmits the response to the electronic circuitry of the lock. Next, the user operates the user interface 108 of the lock. The operating may comprise turning a doorknob or inserting a physical key into the lock. The operation activates the lock and provides operating power for the lock to perform the authentication. In the authentication, the lock authenticates the response. In an embodiment, the response is authenticated against the challenge. If the authentication succeeds the lock is set to an openable state and allows the user to operate the lock bolt.
[0026] In the above-described embodiment, the physical key does not perform any authentication but provides the activation of the operating power of the lock. In some embodiments, the key may provide some additional authentication.
[0027] In an embodiment, the communication device 106 signals the challenge read from the electronic circuitry of the lock to an authentication service 100 using the wireless network channel 104 . The authentication service 100 may calculate the response and transmit it to the communication device 106 .
[0028] In an embodiment, the authentication service may record an audit trail of actions related to the locks of the lock systems. Thus, each attempt to open a lock may be viewed later. In addition, the authentication service may utilize a time-limited access rights management. In an embodiment, the lock may store each action in an audit trail. The authentication service may be realized with one or more computers, servers or computing equipment and associated software.
[0029] Any suitable authentication technique may be used in connection with the embodiments of the present invention. The selection of the authentication technique depends on the desired security level of the lock 106 and possibly also on the permitted consumption of electricity for the authentication (especially in user-powered electromechanical locks)
[0030] In an embodiment, the authentication is performed with a SHA-1 (Secure Hash Algorithm) function, designed by the National Security Agency (NSA). In SHA-1, a condensed digital representation (known as a message digest) is computed from a given input data sequence (known as the message). The message digest is to a high degree of probability unique for the message. SHA-1 is called “secure” because, for a given algorithm, it is computationally infeasible to find a message that corresponds to a given message digest, or to find two different messages that produce the same message digest. Any change to a message will, with a very high probability, result in a different message digest. If the security needs to be increased, other hash functions (SHA-224, SHA-256, SHA-384 and SHA-512) in the SHA family, each with longer digests, collectively known as SHA-2 may be used.
[0031] In an embodiment, the challenge comprises a lock system id, a lock id, access data and a check value. The lock system id identifies the lock system to which the lock belongs. The lock id identifies the lock in the lock system. Each lock in a lock system may comprise a unique identification. The access data may be random numeric data. The check value is a cyclic redundancy check value confirming the integrity of the challenge.
[0032] In an embodiment, the authentication service or the communication device calculating the response may determine on the basis of the response whether the authentication will succeed or not. The communication device 106 may inform the user whether the authentication will succeed or not.
[0033] In an embodiment, a Personal Identification Number (PIN) or finger print data of the user of the communication device may be used when generating a response for the challenge. The communication device may comprise a finger print data reader configured to read a finger print and generate a numeric presentation on the basis of the finger print.
[0034] The challenge may comprise a PIN or finger print query. The user of the communication device may type in the PIN or use the finger print data reader of the communication device. The communication device is configured to send the PIN or the numeric presentation of the finger print as a response to the challenge. The lock may be configured to store a set of PINs and finger prints which allow the opening of the lock. The electronic circuitry of the lock compares the response to the stored values and if a match is found, the authentication is deemed to be successful.
[0035] FIG. 1B shows a more detailed example of an electromechanical lock 116 and a communication device 106 . The communication device comprises a short-range communication unit 140 . In an embodiment, the short-range communication unit 140 is an NFC transceiver of active type. The communication device 106 may comprise a wireless transceiver 107 for realising a wireless network channel connection to a wireless network, such as a GSM network, a WCDMA network or a WLAN network or any other suitable standard/non-standard wireless communication network.
[0036] The lock 116 comprises an electric circuitry 142 . The lock further comprises a user interface 108 and a generator 122 which is configured to power the lock 116 when the user interface of the lock is operated.
[0037] The electronic circuitry 142 may be implemented as one or more integrated circuits, such as application-specific integrated circuits ASIC. Other embodiments are also feasible, such as a circuit built of separate logic components, or memory units and one or more processors with software. A hybrid of these different embodiments is also feasible. When selecting the method of implementation, a person skilled in the art will consider the requirements set on the power consumption of the device, production costs, and production volumes, for example. The electronic circuitry 142 may be configured to execute computer program instructions for executing computer processes.
[0038] In the embodiment of FIG. 1B , the electronic circuitry 142 is realized with two circuits. The circuitry comprises a communication unit 128 and a lock electronics circuit 120 which are connected to each other with a communication channel 118 . In an embodiment, the lock electronics circuit 120 is realized with a microcontroller and a memory unit.
[0039] The lock further comprises an antenna 112 connected to the communication unit 126 . In an embodiment, the communication unit 126 is an NFC transceiver of passive type.
[0040] The lock further comprises an actuator 124 which controls a lock bolt 114 . After a successful authentication the actuator 124 is configured to set the lock in a mechanically openable state. The actuator may be powered by electric power produced with the generator 108 . The actuator 110 may be set to a locked state mechanically, but a detailed discussion thereon is not necessary to illuminate the present embodiments.
[0041] When the actuator 124 has set the lock in a mechanically openable state, the bolt mechanism 114 can be moved by operating the user interface 108 , for example. Other suitable operating mechanisms may be used as well.
[0042] FIG. 2 illustrates an embodiment of the communication unit 126 . It may consist of a communication interface 200 between the antenna 112 and two memory units 202 , 204 . The communication interface 200 with memory units 202 , 204 may be an NFC transceiver of a passive type. When the antenna 112 is within the operating range of an active NFC device (for example the communication device 106 of FIGS. 1A and 1B ) the communication unit 126 is powered through the antenna 112 by the magnetic field generated by the active NFC device. The memory unit 202 is configured to store an authentication challenge and the memory unit 204 is configured to store an authentication response. The active NFC device powers the communication interface 200 with memories 202 , 204 , reads the challenge wirelessly from the memory unit 202 and stores the response wirelessly in the memory unit 204 .
[0043] When the user interface of the lock is operated the communication unit 126 is powered by the generator 122 of FIG. 1B through the interface 206 using the communication channel 118 . The lock electronics 120 read the response from the memory 204 and write a new challenge to the memory unit 202 .
[0044] The memory unit 202 may be permanent memory realized with Flash or EEPROM technology, for example. The memory unit 204 may be non-permanent memory realized with RAM or DRAM technology, for example. The communication unit 126 is configured to store a response in the memory unit 204 only for a predetermined time; otherwise a security risk occurs if a lock is not operated after writing the response. The communication interface 206 illustrates an example of a communication interface between the memory units 202 , 204 and the lock electronics 120 . A read operation of the memory unit 204 and write operation of the memory unit 202 are powered by the lock when operated.
[0045] FIGS. 3A to 3C are flowcharts illustrating embodiments of the invention. Here it is assumed that by default the electromechanical lock 116 of the door 115 is in a locked state and it remains in the locked state until set to an openable state.
[0046] FIGS. 3A and 3B illustrate embodiments from the point of view of the communication device 106 .
[0047] The opening sequence starts is step 300 .
[0048] in step 302 , the user of the communication device 106 initiates the communication device. This may comprise switching the NFC transceiver of the communication device on. The communication device is placed so that the lock antenna is within the coverage area of the NFC transceiver of the communication device. For example, the user may touch the lock antenna with the communication device.
[0049] In step 304 , the communication device 106 transmits an NFC query to the lock.
[0050] In step 306 , the communication device receives the current challenge sent by the lock.
[0051] In step 308 of FIG. 3A , the communication device 106 computes a response. In an embodiment, the response is computed by the processing unit of the communication device 106 . In an embodiment, the response is computed in a Subscriber Identity Module (SIM) or a Universal Integrated Circuit Card (UICC) located in the communication device 106 .
[0052] FIG. 3B illustrates another embodiment, where the communication device 106 transmits the challenge to the authentication service 100 in step 320 .
[0053] In step 322 of FIG. 3B , the authentication service 100 computes a response to the challenge and sends it to the communication device 106 . This embodiment enables a time-limited access rights management and audit trail recording to the authentication service 100 . From thereon, the process continues as in FIG. 3A in the following manner.
[0054] In step 310 , the communication device 106 transmits the response to the communication unit of the lock 116 .
[0055] FIG. 3C illustrates embodiments from the point of view of the electromechanical lock 116 .
[0056] The opening sequence starts is step 330 .
[0057] In step 332 , the communication unit 126 is powered by the transmission of the communication device 106 and the unit receives a query from the communication device.
[0058] In step 334 , the current challenge is read from the memory 202 and transmitted from the interface 200 to the communication device using the antenna 112 .
[0059] In step 336 , the interface 200 of the communication unit receives a response from the communication device 106 . The interface stores the response in the memory 204 . The memory 204 is configured to store the response for a predetermined time period.
[0060] The above operations in the communication unit 126 are powered by the NFC transmission of the communication device.
[0061] In step 338 , the lock receives a user input from the user interface of the lock. The input activates power for the rest of the opening sequence operations.
[0062] In step 340 , a lock electronics circuit 120 reads the current challenge from its internal memory where it is stored.
[0063] In step 342 , the lock electronics circuit 120 computes a new challenge and stores it in its internal memory and in the memory 202 via the channel 118 and the interface 206 .
[0064] In step 344 , the lock electronics circuit 120 roads the response from the memory 204 via the channel 118 and the interface 206 .
[0065] In step 346 , the lock electronics circuit 120 authenticates the response. In an embodiment, the lock electronics circuit 120 authenticates response against the challenge.
[0066] In step 348 it is checked whether the authentication was successful.
[0067] If it was, the lock electronics circuit 120 sends an open command to the actuator 124 of the lock in step 350 . The actuator 124 sets the lock into an openable state.
[0068] If the authentication failed, the lock electronics circuit 120 does not send an open command to the actuator 124 of the lock in step 352 and the lock remains in a locked state.
[0069] Above, step 338 comprised the activation of power for the lock on the basis of the input from the user. The input operations on the user interface may comprise turning a doorknob or inserting a physical key into the lock. The operation activates the lock and provides operating power for the lock to perform authentication.
[0070] In embodiments utilising the lock structure of FIG. 1B , the operating of the user interface 108 of the lock enables the generator to power the lock 116 . The generator may generate electricity from the turning of a door knob or a key insertion.
[0071] FIGS. 4A , 4 B, and 4 C illustrate examples of other embodiments of an electronic locking system.
[0072] In the example of FIG. 4A , the lock antenna 112 is embedded in the door knob 108 . In this embodiment, the door opening sequence may comprise the following steps. At first, a user touches the knob 108 by a communication device 106 . In the second phase, the knob 108 is turned by the user 105 to activate power for authentication and set the lock 116 to an openable state. In the third phase, turning the knob 108 operates the bolt 114 . In addition, a lever type operation interface can be used instead of a bolt structure. The user experiences the second and the third phase as one continuous turn of the knob.
[0073] In the example of FIG. 4B , the lock antenna 112 is located on the door and a key 134 is used for operating a lock 116 . The user interface of the lock comprises a keyhole 144 . In this embodiment the door opening sequence may comprise the following steps. At first, a user touches the antenna 112 with the communication device 106 . In the second phase, the key 134 is inserted into the keyhole 114 of the lock 116 to activate power for authentication and set the lock 116 to an openable state. In the third phase, the turning of the key 134 operates the bolt 114 .
[0074] The example of FIG. 4C illustrates a lock 116 , which is a combination of the lock structures of FIGS. 4A and 4B . The lock of FIG. 4C may have different operation modes. In an embodiment, the lock 116 authenticates both the key 134 and the response received from the communication device 106 . The lock is set into an openable state if both authentications are successful.
[0075] In another embodiment, the lock 116 authenticates the response received from the communication device 106 . The key 134 is only used to operate the lock mechanism.
[0076] In another embodiment, the lock operation may be different for different users. Some users use the key 134 for authentication. Some users (temporary users, for example) use the communication device 106 for authentication and open the lock 116 by turning the knob 108 .
[0077] In an embodiment, features of the invention are realized as software. Embodiments may be realized as a computer program product encoding a computer program of instructions for executing a computer process carrying out the above described steps for operating an electromechanical lock.
[0078] It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims. | 4y
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TECHNICAL FIELD
This invention relates to apparatus for sensing the presence of persons in a room and more particularly to devices of this kind which detect the infrared wavelengths that radiate from the human body. The invention also provides an advantageous method of fabricating a dome shaped lens for use in sensing devices.
BACKGROUND OF THE INVENTION
Devices for sensing the presence of one or more persons in a room are used extensively for the purpose of actuating security alarms and can also serve a variety of other purposes. Energy savings can be realized by using such devices to turn on lights, heating, air conditioning or other equipment only when it is actually needed and to turn such facilities off when a room is unoccupied.
One type of occupancy sensor responds to the infrared energy which is radiated by the human body. Such sensors include a pyroelectric component of the type which exhibits an electrical voltage or a change of electrical resistance in response to infrared radiation. Circuits in the sensor detect this change and respond by transmitting an actuating signal to one or more electrically controlled devices that are to be turned on when the room is occupied.
Such sensors may also include means for intercepting infrared that arrives from different directions and for concentrating the intercepted infrared at the location of the pyroelectric component. This broadens the range of the sensor. Prior sensors typically use reflectors for this purpose. This has an adverse effect on sensitivity as significant losses of infrared energy occur during the process of reflection.
Intercepted infrared can also be focused towards the location of the pyroelectric component by lenses which are inherently more efficient than reflectors. Prior lenses for this purpose have an undesirably narrow field of view and this makes it necessary to provide a complex and costly assembly of such lenses if the sensor must detect a person at any location within a sizable room.
Sensors of the above described kind have a detection pattern which is the outline of region within which the sensor will detect infrared. The ideal pattern varies from room to room. For example, a detection pattern that approximates a square is appropriate for rooms which have a similar configuration while a long narrow pattern is more appropriate for a hallway. Tailoring of the detection pattern to accommodate to the requirements of different rooms is an undesirably complicated process in the prior occupancy sensors as it requires restructuring of a number of different components. Testing of the prior sensors at the time of installation, to assure that it responds to the presence of a person at different locations in a room, is an undesirably complicated and time consuming process.
The present invention is directed to overcoming one or more of the problems discussed above.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a sensor for detecting occupancy of a room which sensor includes a housing, means for detecting changes of infrared radiation intensity and means for actuating at least one electrically controlled device in response to detection of the changes of infrared intensity. A substantially dome shaped infrared transmissive lens is secured to the housing and has a plurality of infrared focusing Fresnel lens segments which face in a plurality of different directions and which are oriented to direct intercepted infrared radiation to the detecting means.
In another aspect of the invention, the lens segments are formed of infrared transmissive sheet material, each lens segment having a plurality of curvilinear grooves formed in the sheet material. The grooves of each lens segment conform to segments of concentric circles of progressively increasing diameter.
In another aspect of the invention the lens includes a substantially dome shaped outer cage having a plurality of infrared transmissive regions that face in different directions. A substantially dome shaped inner cage, also having a plurality of infrared transmissive regions that face in different directions, is nested within the outer cage. A sheet of infrared transmissive material is sandwiched between the inner and outer cages and the lens segments are formed in the sheet of material.
In another aspect of the invention the sensor housing has an opening in one surface and an adapter at the opening supports the infrared detecting means. The dome shaped lens bas a large diameter end disposed against the housing surface in a substantially centered relationship with the adapter.
In another aspect of the invention, a sensor for detecting the presence of persons in a room includes a housing having an opening in the bottom surface and means for enabling attachment of the housing to the ceiling of a room. At least one infrared sensing component is disposed at the opening. The sensor further includes timer means for actuating an electrically controlled device for an interval of time in response to each detection of an abrupt change of infrared intensity by the sensing component or components. A substantially dome shaped infrared transmissive lens is secured to the bottom of the housing and encircles the sensing component or components. The lens has an outer framework and inner framework disposed in a nested relationship and a sheet of infrared transmissive material is nested between the frameworks. The sheet of material has a plurality of grooves in one surface which are shaped to define a plurality of Fresnel lens segments which are oriented to focus intercepted infrared radiation towards the region of the sensing component.
In still another aspect, the invention provides a lens assembly for concentrating radiant energy that arrives from any of a plurality of different directions including opposite directions. A substantially dome shaped outer cage has open areas bounded by framework and a similarly shaped inner cage, also having open areas bounded by framework, is nested in the outer cage. A sheet of radiant energy transmissive flexible material is nested between the outer and inner cages. A plurality of Fresnel lens segments are formed in a surface of the sheet and face in different directions around the perimeter of the lens assembly, each of the lens segments having a plurality of curved grooves which conform to segments of concentric circles of progressively increasing diameter.
In still another aspect, the invention provides a method of fabricating a lens assembly for concentrating radiant energy that arrives from any of a plurality of different directions including opposite directions. Steps in the method include forming a plurality of Fresnel lens segments in a surface of a sheet of radiant energy transmissive flexible material by forming a plurality of curved grooves in each segment that conform to segments of concentric circles of progressively increasing diameter. Formation of the lens segments is performed while the sheet is in a flattened condition. The sheet is cut into a configuration which has a central area and a plurality of petal-like areas that extend in different angular directions around the perimeter of the central area. The petal-like areas are then flexed to form the sheet into a substantially dome shaped configuration. The flexed sheet is sandwiched between a pair of nested dome shaped open frameworks to maintain the sheet in the dome shaped configuration.
The invention provides a room occupancy sensor that can respond to infrared arriving from diverse different locations in a room without requiring reflectors or a costly and complex system of lenses for the purpose. In the preferred form, the sensor has a construction which enables the detection pattern to be altered to accommodate to a particular room with only a minor alteration of components. The preferred form of the invention also facilitates testing by enabling a temporary shortening of the time interval during which the sensor actuates a controlled device following each sensing of a change in infrared intensity and by providing an immediate visible indication that movement of a persons body has been detected. The method of the invention provides an economical and uncomplicated procedure for fabricating a dome shaped lens having an array of differently oriented Fresnel lens segments which lens configuration would be exceedingly difficult to produce by conventional lens manufacturing procedures.
The invention, together with further aspects and advantages thereof, may be further understood by reference to the following description of the preferred embodiments and by reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation view of a room occupancy sensor embodying the invention in which certain electrical devices with which the sensor coacts are shown in schematic form.
FIG. 2 is a view of the underside of the room occupancy sensor of FIG. 1.
FIG. 3 is an exploded perspective view of components of the sensor of the preceding figures.
FIG. 4 is an exploded perspective view of components of a lens which forms a part of the sensor of the preceding figures.
FIG. 5 is a cross section view of an upper side region of the lens assembly.
FIG. 6 is a plan view of an array of Fresnel lens segments as it appears prior to assembly with other components of the lens of FIGS. 5 and 6.
FIG. 7 is a enlarged cross section view of the lens segment array taken along line 7--7 of FIG. 6.
FIG. 8 is a partial cross section view taken along line 8--8 of FIG. 3 and showing the infrared sensing components and a supporting adapter.
FIG. 9 is a view of the underside of the components that are depicted in FIG. 8.
FIG. 10 is a diagram of the floor of a room showing the deflection pattern produced by the arrangement of components depicted in FIGS. 8 and 9.
FIG. 11 is a diagrammatic elevation view of the room and deflection pattern of FIG. 10.
FIG. 12 is a view corresponding to FIG. 8 showing a first modification of the components to provide a different detection pattern.
FIG. 13 is a view of the underside of the components that are depicted in FIG. 12.
FIG. 14 is a view corresponding to FIGS. 8 and 12 but showing a second modification of the components to provide still another detection pattern.
FIG. 15 is a schematic circuit diagram showing a preferred electrical circuit for the sensor of the preceding figures.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring initially to FIGS. 1 and 2 of the drawings in conjunction, a room occupancy sensor 16 in accordance with the invention includes one or more infrared detectors 17 of the known type that produce an electrical voltage in response to irradiation by infrared energy, there being four such components in this particular example. One suitable example of a detector 17 of this kind is manufactured in Japan by Nippon Ceramics Co. Ltd and identified as Model RE200B Pyroelectric Detector.
The infrared sensing components 17 are disposed at the underside of a rectangular housing 19 which has spaced apart vertical passages 21 for receiving screws (not shown) to attach the sensor 16 to the ceiling of a room preferably at an electrical gang box of the standardized form. An inverted dome shaped lens 22 is also secured to the underside of housing 19 and is centered under the detectors 17. As will hereinafter be described in more detail, lens 22 intercepts infrared that is radiated by persons in the room and focuses the infrared towards a detector 17.
For purposes of example, FIG. 1 depicts the sensor 16 as being used to turn on a light bulb 23 when one or more persons enter the room and to turn off the light after the room becomes unoccupied. The sensor 16 may also be used to actuate and deactuate any of a variety of other electrically controlled devices of which heating installations, air conditioners and burglar alarms are examples. The sensor 16 may be connected to control a number of such devices simultaneously.
The controlled device such as light bulb 23 may be connected across standard A.C. utility power conductors 24 and 26 through contacts 27 of a normally open relay 29. Relatively low voltage D.C. current for operating sensor 16 and relay 29 may be provided by connecting the primary winding of a voltage step-down transformer 31 across the utility power conductors 24 and 26 and by connecting the secondary side of the transformer to a rectifier 32. The low voltage direct current output of rectifier 32 is transmitted to sensor 16 by first and second sensor lead wires 33 and 34. The driver coil 36 of relay 29 is connected across the second lead wire 34, which is the negative D.C. lead wire, and a third lead wire 37 of the sensor 16. In the United States of America, utility power conductors 24 and 26 typically provide 60 cycle, 115 volt alternating current. Transformer 31 and rectifier 32 may be selected to provide 24 volt direct current to the sensor 16 as this enables use of economical low voltage wiring.
Transformer 31, rectifier 32 and relay 29 can be the corresponding components of a standard power pack of the type which is widely used in building wiring systems and the present embodiment of the invention is designed to be coupled to such a power pack. Alternately, the transformer 31, rectifier 32 and relay 29 can be components of the sensor 16 itself which are contained within housing 19 in which case the sensor is connected directly to the A.C. utility power conductors 24 and 26.
As will hereinafter be described in more detail, housing 19 contains a timer circuit 39 which responds to signals from the detectors 17 by energizing relay driver coil 36 for a limited period of time and then de-energizing the coil if no subsequent detector signal has been produced during that time period.
Referring to FIG. 2 in particular, additional externally visible components of this embodiment include first and second rotary variable resistors 41 and 42 which respectively enable adjustment of the sensitivity of the sensor 16 to changes of infrared intensity and variation of the above discussed on time interval that is established by the timer circuit. The time interval may be varied within the range of 6 minutes to 15 minutes in this particular embodiment to accommodate to the amount of human activity that occurs in a particular room although other time periods can also be appropriate. The shorter times provided by adjustment of variable resistor 42 are appropriate in large rooms where a high level of human activity occurs such as in a school classroom as one example. Motions of a human body of the type to which the sensor 16 responds occur almost continually in rooms of this kind. The longer time periods are appropriate at locations where a single individual or a small number of persons may be present and where the person or persons may be inactive at times.
Two key slots 43 and 44 are provided in the underside of housing 19. As will further described, insertion of a key into slot 43 causes a bypassing of the sensor 16 circuits when it is desired to maintain the controlled device in an on condition regardless of occupancy of the room. Insertion of a key into slot 44 foreshortens the above disussed timer interval to facilitate testing of the response of the sensor 16 following installation. Testing is also facilitated by a pair of light producing devices such as light emitting diodes 46 which are disposed at visible locations on the underside of housing 19. As will be further described, diodes 46 blink on momentarily each time that a change of infrared intensity is detected and processed. This enables testing of the response of the sensor 16 from various locations in the room by simply waving a hand. The diodes 46 are situated at diametrically opposite sides of lens 22 to enable viewing of at least one of the diodes from any location in the room.
Small bolts 47, visible at the underside of housing 19, hold the components of the housing together.
With reference to FIG. 3, the housing 19 may have a tray shaped bottom member 49 and a conforming flat top cover 51 which seats on small inwardly extending ledges 52 formed in opposite end walls of the bottom member. The bottom member 49 and top cover 51 are preferably formed of metal to shield the interior of housing 19 from radio frequency interference.
A printed circuit board 53, carrying components 54 of the circuit which will be hereinafter described, is contained between bottom member 49 and cover 51. Conforming rectangular sheets 56 and 57 of insulative paper are disposed immediately above and below circuit board 53 to prevent contact of the circuit components with the metal cover 51 and bottom member 49.
Bottom member 49, insulative sheets 56 and 57 and cover 51 are provided with aligned openings 59 to receive the screws or the like which fasten the sensor to a ceiling. Each such component also has additional aligned openings 61 to receive the bolts which fasten the components of the housing 19 together. Circuit board 53, the upper insulative sheet 56 and cover 51 have still other aligned openings 62 through which the three electrical leads 33, 34 and 37 extend to the exterior of housing 19 when the components are assembled. Relatively large circular openings 63 at the centers of bottom member 49 and in the lower insulative sheet 57 enable an adapter 64, which carries the infrared detectors 17 (shown in FIG. 1), to extend from circuit board 53 down into the upper region of the dome shaped lens 22. Additional openings 66 in bottom member 49 and lower insulative sheet 57 provide access to the variable resistors 41 and 42 (shown in FIG. 1) which are secured to the underside of the circuit board 53.
Referring jointly to FIGS. 4 and 5, the lens 22 functions to intercept infrared that arrives from different angular directions, including opposite directions, and to focus and concentrate the intercepted infrared towards at least one of the previously described detectors. Components of the lens 22 include a dome shaped outer cage or framework 67 having open areas 69 that face in different directions around the perimeter of the cage. The upper rim portion 71 of cage 67 is preferably of octagonal configuration and the lower end portion 72 is of similar configuration but of smaller diameter. Curved rib portions 73 of cage 67 extend between the angulations 74 of the upper and lower portions 71 and 72.
An inner cage or framework 76 has a configuration similar to that of the outer cage 67 except that it is proportioned to fit within the outer cage in a nested relationship. Resilient hooked tabs 77 extend up and slightly inward from locations around the upper rim portion 71 of outer cage 67 to snap engage the two cages 67 and 76 in the nested relationship. As best seen in FIG. 5 in particular, the tabs 77 are deflected outward as the inner cage 76 is forced into the outer cage 67 and then spring back over the top of the inner cage to latch the two cages together.
Referring again to FIGS. 4 and 5 in conjunction, focusing of infrared onto the detectors is effected by a lens element 79 which is fabricated from infrared transmissive flexible material and which is formed into a dome shaped configuration conforming to the shape of the cages 67 and 76 to enable the lens element to be sandwiched between the nested cages. One surface, preferably the inner surface, of lens element 79 is formed to provide an array of Fresnel lens segments 91 which extend transversely across the open area 69 of cages 67 and 76 when the lens 22 components are assembled. An additional group of such lens segments 91a, shown in FIG. 6, face downward and extend across the lower end portions 72 of the cages 67 and 76 when the lens components are assembled. Referring again to FIGS. 4 and 5, the lens segments 91 at each open area 69 are oriented to focus intercepted infrared at the same location which is situated near the top of the lens 22 assembly to enable detection of the focused infrared by a detector. The downwardly facing lens segments 91a are oriented to focus intercepted infrared rays at a location which is at the vertical centerline of the dome shape lens 22 and at the top region of the lens.
Referring jointly to FIGS. 6 and 7, the surface of a Fresnel lens has a series of grooves 92 that conform with concentric circles of progressively increasing diameter. In the present instance a majority of the grooves 92 of each lens segment 91, 91a conform with only segments of such circles owing to the elongated essentially rectangular shape of the lens segments. Faces 93 of the successive groves 92 are curved to jointly provide the focusing effect of an ordinary ungrooved and much thicker convex lens.
The invention enables fabrication of a domed shaped array of Fresnel lens segments 91, 91a in a much more economical manner than would be possible if conventional lens manufacturing techniques were used. In particular, the grooves 92 of all lens segments 91, 91a may be die stamped, molded or be otherwise formed simultaneously in one operation as this may be done while the lens element 79 is still in a flat condition. Prior to or after formation of the grooves 92 the material of the lens element 79 is trimmed to provide an octagonal central area 94 and eight arms 96 that extend outward from the central area at equiangular intervals around the perimeter of the central area. Referring jointly to FIGS. 4 and 6, the central area 94 is proportioned to conform in outline with the lower portions 72 of cages 67 and 76 and the arms 96 are trimmed to span the open areas 69 of the cages when the arms are flexed into a curvilinear configuration conforming to the curvature of the ribs 73 of the cages.
The flexed lens element 79 is then nested between the cages 67 and 76 and is held in the dome shaped configuration by the clamping action of the nested cages and preferably also by adhering the edges of arms 96 to each other and to the cages with a suitable adhesive.
The above described lens 22 assembly provides further manufacturing economies in that only minor changes in the construction of the sensor are needed to provide a variety of different detection patterns. Referring jointly to FIGS. 8 and 9, the adapter 63 which supports the infrared detectors 17 has three conductive pins 97 which extend up through the center of circuit board 53 and which are the electrical terminals of the detectors. Solder beads 99 at the upper ends of pins 97 function both to hold the adapter 63 at the circuit board 53 and to provide for electrical connections to printed circuits on the board. The lower portion of adapter 63 has four flat sides 101 which face outward in directions that are at right angles to each other and which are also inclined at an angle which may be about 30° away from vertical. Each of the four infrared detectors 17 is secured to a separate one of the sides 101 with the optical axis 102 of each detector being normal to the side 101 at which the detector is secured to the adapter 63. Referring to FIGS. 1 and 8 in conjunction, adapter 63 in this particular embodiment is oriented to cause the detectors 17 to be directed towards the ones of the lens arms 96 that are diagonally positioned relative to the sides and ends of the sensor 16. This provides for maximum range when the sensor 16 is secured to the center of the ceiling of a square room 103 in parallel relationship with the walls of the room as the optical axes 102 of the detectors are directed at the corners of the room which are the portions of the room that are most distant from the sensor.
Referring jointly to FIGS. 10 and 11, dashed outline 104 indicates the detection pattern of the above described embodiment of the invention. The room outlined at 103 has sides which are fifty feet in length. Sensor 16 is responsive to waving of a human hand at the boundaries of the room that are within dashed outline 104 and detects one walking step at the narrow tapered zones 106 in which response is reduced by the octagonal configuration and opaque framework of the lens 22 assembly. Small areas 107 of reduced response are also present at the midpoint of each wall. These areas 107 are not present in a room 109 which has sides that are thirty-eight feet in length or in smaller rooms.
Differing detection patterns may be more suitable for some rooms. For example, a relatively narrow detection pattern is appropriate for a hallway or corridor. Referring jointly to FIGS. 12 and 13, this may be provided for by mounting the adapter 63 in an orientation at which it is rotated 45° from the orientation which has been previously described and by providing only two detectors 17 which are situated on the adapter sides 101 that face towards the ends of the sensor 16. Referring to FIG. 2, the detectors then receive focused infrared through the ones of the lens element arms 96 that are parallel to the ends of the sensor 16.
The lens 22 configuration is also compatible with sensors 16 for smaller rooms that have only one detector. Referring to FIG. 14, a modified adapter 63a for this purpose may have a cylindrical configuration and the single detector 17a may be secured to the bottom surface of the adapter and be directed downward. Referring jointly to FIGS. 2 and 14, the detector 17a then receives infrared through the flat central area 94 at the base of the lens 22 and also from each of the arms 96 of the lens if the adapter is proportioned to position the front end of the detector at the location where the infrared rays from each such arm intersect each other.
In some instances it may be desirable to make the sensor 16 insensitive to infrared which originates at one or more particular locations in a room. Some appliances, for example, emit varying levels of infrared energy that could affect operation of the sensor 16. Referring to FIG. 2, this is readily accomplished by masking those portions of the lens 22 which are directed towards such infrared sources with pieces of infrared opaque material 111 which are sized to conform with the area of the lens that is to be made insensitive and which are attached to the lens with adhesive or by other means
Referring to FIG. 15, circuit components which are formed on or supported by the printed circuit board 53 include a low voltage D.C. power supply 112 which receives the 24 volt D.C. voltage from the previously described first and second sensor lead wires 33 and 34 and which has an output terminal 113 which provides a lower voltage for operating the solid state components of the circuit. The negative lead wire 34 is also connected to a chassis ground which is designated by a inverted triangle throughout FIG. 15.
The four detectors 17 each have identical components and have identical pulse output circuits 114 and thus only the first detector and pulse output circuit is depicted in detail in FIG. 15. Each such detector includes a small body 116 of one of the known pyroelectric materials which exhibit a change of electrical potential when the material is irradiated by infrared energy. Each detector also includes an FET transistor 117 having a source terminal which receives voltage from the low voltage power supply terminal 113 through a resistor 119, a drain terminal connected to ground through a resistor 121 and a gate terminal which is connected to ground through still another resistor 122. The pyroelectric body 116 is connected in parallel with the gate resistor 122 and thus provides a gating signal which controls conduction through the transistor 117. This causes the voltage drop across resistor 121 to vary in response to variations of the intensity of the infrared that reaches the pyroelectric body 116.
A high gain first operational amplifier 123 functions to amplify the weak detector signals to a magnitude suitable for processing by other components of the circuit. The positive or non-inverting input of amplifier 123 is connected to low power terminal 113 through a voltage dropping resistor 120 and to ground through another resistor 124. The negative or inverting input is connected to ground through still another resistor 126. Electrical pulses indicative of voltage variations at the output of transistor 117 are transmitted to the positive input through a input resistor 127 and input capacitor 129. A smaller capacitor 131, connected between the input side of capacitor 129 and ground, suppresses circuit noise. Feedback resistor 132 and compensating capacitor 133, connected in parallel between the output and negative input of amplifier 123, establish the desired high gain characteristics.
As the detector signals are transmitted to amplifier 123 through a capacitor 129, the amplifier operates in a differentiating mode and is responsive to rate of change of the amplitude of the signals rather than to the absolute amplitude of the signal. This enables the sensor to respond only to abrupt changes of infrared intensity. Slower changes can arise from causes other than human activity. For example, solar radiation entering the room may vary throughout the day. The sensor is in effect a detector of movement of a human body.
A second amplifier 134 and third amplifier 136 enable adjustment Of the sensitivity of the sensor to infrared fluctuations. Output pulses from the first amplifier 123 are transmitted to the positive input of the second amplifier 134 which has a negative input connected to ground through another resistor 137. Feedback components of second amplifier 134 which are connected between the output and negative input of the second amplifier 134 include the previously described variable resistance 41 which is in series with a fixed resistance 139, a compensating capacitor 141 and two oppositely oriented diodes 142. The variable resistance 41 enables selective adjustment of the gain of the second amplifier 134. Diodes 142 establish a bandwidth for the amplifier output pulses.
The third amplifier 136 is configured as a comparator and produces a timer circuit triggering signal in response to output pulses from second amplifier 134 that have an amplitude equal to or greater than a particular fixed value. This enables the sensitivity adjustment since the gain of second amplifier 134 can be varied by adjusting the variable feedback resistor 41.
The output pulses from second amplifier 134 are transmitted to the positive input of the third amplifier 136 through another capacitor 143 and the positive input is also connected to ground through resistors 144 and 146 which are in series. The negative input of comparator amplifier 136 receives reference voltage from low voltage terminal 113 through an input resistor 147 and additional resistor 149 is connected between the negative input and the ]unction between resistors 144 and 146. Thus the resistors 147, 149 and 146 jointly act as a voltage divider and fix the magnitude of the reference voltage that is applied to amplifier 136. A capacitor 151 is connected between the negative input and ground to suppress transient voltage fluctuations at the input.
The output pulses from third amplifier 136 cause charging of a high value capacitor 152 of the timer circuit 39. For this purpose, one side of capacitor 152 is grounded and the other side is connected to the emitter of an NPN transistor 153. The collector of transistor 153 receives positive voltage from low power terminal 113 and output pulses from third amplifier 136 are transmitted to the base of the transistor through a resistor 154. Thus transistor 153 is turned on and delivers charging current to timer capacitor 152 during each amplifier output pulse.
The previously described variable resistor 42 and a fixed resistance 156 are connected between the input side of capacitor 152 and ground to discharge the capacitor over a period of time unless it is recharged during that period by detection of another abrupt infrared energy fluctuation. As previously described, the variable resistor 42 enables adjustment of the discharge time period to meet the needs of a particular room.
A PNP transistor 157 transmits 24 volt current from the first sensor lead wire 33 to the third or output lead wire 37 of the sensor during periods when capacitor 152 is charged to a predetermined voltage level or to a higher level. The collector of transistor 157 receives current from the first lead wire 33 and the emitter of the transistor is connected to the third or output lead wire 37 through a current limiting resistor 160.
To control transistor 157, a fourth amplifier 159 with a high feedback resistance 161 has a positive input which is connected to the timer capacitor 152 through resistor 162 and a negative input which receives voltage from low power terminal 113 through a resistor 163. The negative input is also connected to ground through another resistor 164. Thus amplifier 159 produces an output voltage when timer capacitor 152 is charged above a particular voltage that is fixed by the relative values of resistors 163 and 164 which function as a voltage divider.
Output voltage from fourth amplifier 159 is transmitted to the base of another NPN transistor 166 through a resistor 167. The emitter of transistor 166 is grounded and the collector of the transistor receives voltage from sensor lead wire 33 through resistor 169. Thus transistor 166 is biased into conduction by the output voltage from fourth amplifier 159. The base of the previously described transistor 157 is connected to the collector of transistor 166 by a resistor 171. Thus transistor 157 is turned on by the voltage drop which occurs at the collector of transistor 166 when transistor 166 itself becomes conductive. This applies 24 volt current from sensor input lead 33 to the output lead 37 to actuate the device which is controlled by the sensor in the manner which has been previously described.
Still another NPN transistor 172 functions to turn off the timer capacitor charging transistor 153 after each charging of timer capacitor 152 so that amplifier 159 may respond to the voltage on the capacitor rather than to voltage received through transistor 153. For this purpose, the collector of transistor 172 is connected to the base of the charging transistor 153 and the emitter of transistor 172 is grounded. A resistor 173 is connected between the base of transistor 172 and ground.
Transistor 172 is briefly biased into conduction after charging of the timer capacitor 152 by still another PNP transistor 174. The emitter of transistor 174 is connected to low voltage terminal 113 and the base is coupled to terminal 113 through a resistor 176. The collector of transistor 174 is connected to the base of transistor 172 through a resistor 177 and thus to ground through resistor 173. The output of amplifier 159 is coupled to the base of transistor 174 through a capacitor 175 and input resistor 179. Consequently, the leading edge of the amplifier 159 output which results from each charging of timer capacitor 152 briefly gates transistor 174 into conduction. This turns transistor 172 on momentarily to bring about a brief grounding of the base of transistor 153 which abruptly stops conduction through that transistor. This allows the timer capacitor 152 to discharge slowly through the high resistances 42 and 156 and enables amplifier 159 to respond to the decaying voltage after a period of time by turning off the sensor output controlling transistors 157 and 166 unless a recharging of the capacitor has occurred in the interim.
As previously described, testing of the sensor following installation can be expedited by temporarily foreshortening the time interval during which the sensor actuates a controlled device following detection of an infrared fluctuation. For this purpose, a pair of spaced apart contacts 191 and a resistor 192 are connected in series between ground and the voltage input side of timer capacitor 152. Foreshortening of the time interval is accomplished by temporarily inserting the blade of a metal key 193 between contacts 191 to establish a conductive path from the capacitor 152 to ground through resistor 192. The resistance of resistor 192 is lower than that of the resistors 42 and 146 and thus decay of the charge on capacitor 152 occurs more rapidly than is the case when the key 193 is absent.
Key 193 or a similar key may also be used to effectively bypass the sensor at times when it is desired that the controlled device remain on without regard to human occupancy of the room. For this purpose, one of another pair of spaced apart contacts 194 is connected to the sensor power input lead wire 33 and the other contact is connected to the sensor power output lead wire 37 through current limiting resistor 160. Bridging of contacts 194 with the blade of key 193 results in a continual flow of current to the controlled device.
The previously described light emitting diodes 46 which blink on and off each time that motion of a human body is detected are connected between low power terminal 113 and the collector of another NPN transistor 196 in series with each other and in series with a resistor 197, the emitter of the transistor being grounded. Another resistor 199 transmits the output pulses from comparator amplifier 136 to the base of transistor 196 to momentarily turn the transistor on in response to each pulse and thereby cause momentary light emission from diodes 46.
Referring again to FIG. 1, the domed lens 22 configuration as herein described is adapted to focus infrared onto one or more infrared detectors 17. The lens construction can be also be adapted to focus other wavelengths, such as visible light, towards detectors by using lens materials that are transmissive of the other wavelengths.
While the invention has been described with respect to certain specific embodiments for purpose of example, many variations and modifications are possible and it is not intended to limit the invention except as defined in the following claims. | 4y
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This invention relates to a power supply and it relates especially, though not exclusively, to a power supply suitable for an arc discharge lamp.
An arc discharge lamp is usually driven at a frequency well above the flicker threshold of the human eye in order to facilitate an overall reduction in component size associated with the ballast, and typically a frequency in excess of 20kHz is used. It is well known, however, that an arc tube can support longitudinal and lateral acoustic waves at these relatively high frequencies and this phenomenon, which is commonly referred to as "acoustic resonance", can occur whenever power is supplied to the lamp at, or about, certain resonant frequencies F M which are related to lamp geometry by the expression ##EQU1## where M is an integer representing harmonic number, L is related to the length of the arc tube,
and V is the acoustic velocity in the arc tube.
In general, an arc discharge lamp may exhibit many such resonant frequencies and since M, L and V may all depend on the operating characteristics of the lamp, these frequencies can vary over the running time, and lifetime of the lamp.
Acoustic resonance has proved to be particularly problematical since the acoustic wave may give rise to an instability in the discharge arc, causing it to stretch or gyrate and invariably to extinguish. In some cases damage may be caused to the arc tube.
The problem of acoustic resonance has taxed workers in the field for many years. Solutions which have been proposed include shaping the supply waveform, specially configuring the arc tube and placing quartz wool inside the arc tube. None of the solutions yet proposed appears to have been altogether successful and, in some cases, the proposed solution could conflict with other lamp design considerations such as lamp life, efficacy etc.
SUMMARY OF INVENTION
It is therefore an object of the present invention to provide a power supply suitable for an arc discharge lamp which at least alleviates some of the problems outlined hereinbefore.
Accordingly there is provided a power supply suitable for an arc discharge lamp, the power supply comprising a drive circuit arranged to supply voltage to the lamp and control means for causing a characteristic of said voltage to vary with time in accordance with a pseudo random sequence in order to reduce, or eliminate, acoustic resonance in the lamp.
The voltage supplied to the lamp comprises a spread spectrum signal in which power is spread over a band of frequencies, and the inventor has found that the resulting lamp operation is substantially free from acoustic resonance.
In an embodiment of the invention said drive means and said control means cooperate to supply a succession of voltage pulses to the lamp, each pulse being of a duration selected in accordance with said pseudo random sequence. In another embodiment of the invention said drive means and said control means cooperate to supply said voltage at a succession of frequencies within a pre-determined bandwidth, the frequencies in said succession being selected in accordance with said pseudo random sequence.
It will be understood that each frequency in said succession of frequencies may occur once only or, alternatively, each frequency may occur more than once.
Said control means may include a frequency generator comprising a pseudo-random sequence generator operating in association with a frequency dividing means, and the pseudo random sequence generator may be of the well known simple, or alternatively modular, shift register generator. It will be understood that other types of pseudo random sequence generator could be used and, by application of appropriate code sequence design, their operation may be arranged to generate different linear and non-linear sequences.
In an alternative arrangement in accordance with the invention said control means may comprise means for storing a preselected pseudo random sequence of numbers and a frequency dividing circuit effective to translate said pseudo random sequence of numbers into said pseudo random sequence of frequencies.
In these circumstances, said control means may include means for routing said preselected pseudo random sequence of numbers repeatedly to said frequency dividing means. Said storage means may comprise a plurality of storage locations each containing a respective one of said preselected pseudo random sequence of numbers said storage locations being addressable successively in accordance with a cyclical operation.
Said control means may further include means for regulating the number of cycles at each of said succession of frequencies.
BRIEF DESCRIPTION OF DRAWINGS
In order that the invention may be carried into effect specific embodiments thereof are now described, by way of example only, by reference to the accompanying drawings of which: FIG. 1 illustrates a power supply including a drive circuit having a half-bridge configuration;
FIG. 2 illustrates a power supply including a drive circuit having a full bridge configuration;
FIGS. 3a and 3b illustrate different forms of pseudo random sequence generator which can be used in the power supply of FIGS. 1 and 2.
FIG. 4 illustrates a frequency generator used in one embodiment of the invention;
FIG. 5 illustrates a memory circuit replacing a pseudo-random sequence generator of FIG. 4;
and FIG. 6 illustrates a power supply in accordance with another embodiment of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 of the drawings illustrates a power supply which is designed to drive a high pressure arc discharge lamp (e.g. a metal halide HID lamp), represented generally at 1.
The supply includes a drive circuit, referenced generally at 10, which comprises two, individually energizable, solid state switching devices, in the form of two field effect transistors 2, 3, connected in series across D.C. supply rails 4, 5. In this embodiment of the invention the switching devices are controlled by a frequency generator 20 which is arranged to supply to the drive circuit a train of square wave pulses at a succession of frequencies. One of the switching devices (e.g. 2) is rendered conductive whenever the output of the frequency generator goes high, whereas the other switching device (eg 3), which is connected to the frequency generator via an inverter circuit 6, is rendered conductive whenever the output of the generator goes low. Thus, in operation of the power supply circuit, the two switching devices are effective to couple the supply rails 4, 5 alternately to one end only of the lamp. As is conventional, the power supply circuit includes an LC ballast circuit which can be driven at, or close to, its resonant frequency in order to ignite the lamp. Typically, using an inductance L of 650 μH and a capacitance C of 200 nF it is possible to generate an ignition voltage as high as 2.5kV by driving the lamp at a frequency close to the resonant frequency 51KHz. Once the lamp has ignited its electrical resistance falls and so a substantially lower drive frequency, typically in the range 20-40 kHz, may then be used.
FIG. 1 illustrates a power supply circuit having a so-called "half bridge" configuration, whereas FIG. 2 shows an alternative form of power supply circuit having a "full bridge" configuration. In this case frequency generator 20 controls respective pairs of switching devices (2,2', 3,3') which are arranged to couple the supply rails alternately to opposite ends of the lamp. It will be apparent to workers in the field that other circuit configurations, suitable for supplying DC or AC power to the lamp, could be used.
In this embodiment, frequency generator 20 is designed to generate a succession of frequencies --so called "spot" or "hop" frequencies --which are selected in accordance with a pseudo random sequence and, to this end, the frequency generator incorporates a pseudo-random sequence generator.
FIG. 3a illustrates, by way of example, one form of sequence generator, known as the "simple shift register generator" (SSRG) which comprises an n-stage shift register 21 operating in conjuction with a feedback circuit 22. The shift register generates successively 2 n -1, n-bit binary numbers with the n th -bit, represented as λn, being combined in the feedback circuit with one or more bits, λp say, derived from a selected one, or selected ones, of the shift register stages thereby to create a feedback bit represented as λo. In the case of n=8, the sequence generator produces 255, 8-bit, binary numbers successively, in pseudo random order, at the output ports 0/P of the shift register stages (S1,S2 . . . S8).
It will be appreciated that the feedback bit may be evaluated using any one of a large number of different coding formats known to those skilled in the art. Moreover, it will be understood that the random sequence generator illustrated in FIG. 3a is presented by way of example only. Other known configurations of random sequence generator could be alternatively used and one such, known as the "modular shift register generator" (MSRG), is shown in FIG. 3b.
The frequency generator 20 operates to translate a pseudo-random sequence of m integers, 1 to 2 n -1, produced by the sequence generator, into a corresponding pseudo-random sequence of m frequencies spanning a desired frequency range from f 1 . . . f 2 . This is accomplished by dividing a relatively large fixed frequency f c by m successive integers, n 2 +p, where p is the current integer generated by the pseudo random sequence generator and n 2 is an offset integer defining the upper bound f 2 of the desired frequency range i.e. ##EQU2## It can be shown that ##EQU3## and, in a typical example, m =255, f 1 =20 kHz and f 2 =24kHz. In these circumstances the fixed frequency f c should be at least 30.6MHz, and, in practice, a frequency of 32MHz has been used.
The pseudo random frequency generator illustrated, in block schematic form, in FIG. 4 includes a pseudo random sequence generator 20 comprising a shift register 21 and a feedback circuit 22, as described hereinbefore by reference to FIG. 3a. An eight bit binary number produced by the sequence generator is passed to an arithmetic processor 23 where it is added to an offset number n 2 defining the desired, upper frequency bound f 2 . The resulting sum is then routed, via a multiplexor 24, to a first counter 25 which is arranged to count pulses at a fixed frequency produced by a 32MHz oscillator 26. When the count value and the sum are equal the first counter produces an output pulse and is reset. In effect, therefore, the first counter divides the fixed, 32 MHz frequency by an appropriate factor to generate, at an output (OUT), a drive signal for the lamp at a frequency which lies within a desired frequency band and corresponds to the current value of an integer produced by sequence generator 20.
A pre-conditioned control circuit 27 determines the number of cycles produced at each of the frequencies in the pseudo-random sequence and a second counter 28, which is arranged to monitor the output of the first counter 25, routes a clock pulse CK to shift register 21 of sequence generator 20 when the required number of cycles has been detected. Each clock pulse CK initiates generation of the next number in the pseudo-random sequence.
It will be appreciated that the number of cycles generated need not necessarily be the same for each of the frequencies in the pseudo random sequence. Indeed, the number of cycles generated at each frequency may be tailored to suit a particular lamp and or mode of operation.
In order to ignite the lamp, multiplexer 24 is conditioned to route a predetermined ignition count value from a store 29 to the first counting circuit 25. As before, circuit 25 is arranged to count a required number of fixed frequency pulses produced by oscillator 26, the ignition count value being chosen to correspond to a single ignition frequency, and the control circuit 27 being conditioned to ensure that the number of ignition cycles produced is sufficient to cause ignition of the lamp.
In an alternative embodiment of the invention, pseudo random sequence generator 20 of FIG. 4 is replaced by a memory-based circuit of the form shown generally in FIG. 5.
With this arrangement, a preselected pseudo-random sequence of integers is stored in a memory 40, successive integers in the sequence being accessed, in turn, to the arithmetic processor 23 of FIG. 4. To this end, a further counting circuit 41 is arranged to address a respective storage location of memory 40 in response to each succeeding clock pulse produced by counting circuit 28. At the end of the sequence counting circuit 41 is reset and the same sequence is repeated.
It will be understood that a pseudo-random sequence of frequencies produced as described hereinbefore may, if desired contain a frequency more than once and in this way the spectral density of the drive signal can be tailored to suit a particular lamp configuration.
In a yet further embodiment of the invention, illustrated in FIG. 6, a pseudo random sequence generator of the kind described by reference to FIG. 3a is arranged to produce a pseudo random sequence of binary bits --a direct sequence --which is routed directly to a drive circuit of the kind referenced at 10 in FIG. 1 for example and, in response, the drive circuit supplies a succession of voltage pulses to the lamp each being of a duration selected in accordance with the pseudo-random sequence. Again, it would alternatively be possible to employ a memory-based circuitry including a memory for storing said pseudo random binary sequence.
It will be appreciated that a power supply in accordance with the present invention, whether it be configured to operate using a succession of "spot frequencies", as described by reference to FIGS. 1 to 5, or using a "direct sequence", as described by reference to FIG. 6, supplies to the lamp a spread spectrum signal in which the power is spread over a band of frequencies, and the inventor has found that the resulting lamp operation is substantially free from acoustic resonance.
While the circuitry described hereinbefore may be embodied in hard-wired form, the circuitry could alternatively be embodied using known VLSI techniques. Moreover, the inventor envisages that the components of the power supply (including the ignition circuitry, if desired) could all be fabricated on a single chip. Clearly a silicon-based power supply, being relatively light weight and compact, would present considerable advantages over hitherto known circuitry.
It will be appreciated that a power supply in accordance with the present invention could also be used to supply power to other electrically driven apparatus requiring a high frequency supply. | 4y
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CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part application of Application Ser. No. 923,356, filed July 10, 1978 and now abandoned, which is a continuation of Application of Ser. No. 780,994, filed Apr. 13, 1977, now U.S. Pat. No. 4,099,395, dated July 11, 1978.
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to improvements in tumbler pin-type cylinder locks which are provided with novel safety means which reduce the chances that the lock can be picked or rendered ineffective.
2. Description of the Prior Art
It is well established that experts in opening locks of the tumbler pin-type can relatively easily force with picklocks, locks which operate solely by rotating, radially the lock cylinder relative to the cylinder housing.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a tumbler pin-type cylinder lock wherein the cylinder must be moved axially or axially and radially in respect to the lock housing and movement of the lock cylinder in the axial direction is brought about by cooperating in a conical way the surfaces in the center bore of the lock cylinder and pointed element of the inner end of the key.
It is another object of the present invention to provide such a tumbler pin-type cylinder lock having a unique cylinder provided with various grooves which may be of plural depths to control electric, hydraulic, and/or mechanical locking controls.
It is a further object to provide such a lock provided with a cylinder which has a conical axial depression and a cooperating pointed element at the inner end of the key.
SUMMARY OF THE INVENTION
The hereinbefore objects and advantages of the present invention and others, which will be apparent to those skilled in the art, are generally provided by a tumbler pin-type cylinder lock comprising a housing having a cylinder bore therein, a plurality of tumbler pin bores in the housing normal to the cylinder bore and intersecting the same, a lock cylinder mounted in the cylinder bore for controlled movement relative to the housing, cylinder control tumbler pins mounted in the tumbler pin bores, a key having a profile conforming to the tumbler pin combination and a pointed stop member at the inner end of the key with the stop member engaging a cooperating conical depression on the lock cylinder for axially moving the cylinder within the cylinder bore in the lock housing.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be more particularly described in reference to the accompanying drawing wherein:
FIG. 1 is a partial sectional view through an improved tumbler pin-type cylinder lock constructed in accordance with the present invention.
FIG. 2 is an exploded perspective, partial sectional view through the improved tumbler pin-type cylinder lock shown in FIG. 1;
FIG. 3 is a perspective, partial sectional view of the lock cylinder illustrated in FIG. 1;
FIG. 4 is a fragmentary transverse section of the cylinder showing the two-level pin groove;
FIG. 5 is a fragmentary, partial, sectional view of a modified form of the present invention;
FIGS. 6 and 7 are fragmentary perspective views of modified forms of cylinder ends showing cavities or grooves differing from that shown in FIGS. 1-4; and,
FIG. 8 is a fragmentary, perspective view of a cylinder and housing of a modified configuration.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to the drawing and particularly FIGS. 1, 2, 3, and 4, 10 generally designates an improved tumbler pin-type cylinder lock embodying the features of the present invention useful in association with automotive ignition switch means, and a steering wheel lock mechanism as shown in my U.S. Pat. No. 4,099,395.
The lock 10 includes a cylinder housing 12, having a lock cylinder receiving bore 14 therein. Mounted within the bore 14 is a lock cylinder 16 mounted for both axial and radial movement relative to the cylinder housing 12.
The cylinder housing is provided with a plurality of bores designated 18a, b, and c, which bores are normal to the cylinder bore 14, and normal or opposed to each other as the case may be, and positioned to intersect said bore 14. The bores 18a, b and c receive tumbler pins 19 and tumbler pin springs 21. In the illustrated form of the invention, three banks of tumblers are illustrated, however, it will be appreciated that the invention includes tumbler locks wherein there are only one or only opposed or four banks of tumbler pins as is known in the art.
The cylinder 16 is provided with corresponding tumbler pin bores 20a, b, and c, which receive tumbler pins, again, all as known in the art. Between the tumbler pin bores 20a, b and c, and the shaped end 22 of the cylinder 16, the curvilinear surface of the cylinder is provided with a compound groove generally designated 24. The compound groove or slot is provided with a portion 24a, primarily directed in an axial direction and a portion 24b, primarily oriented in a radial direction relative to the longitudinal length of the cylinder 16.
It will be particularly noted from FIG. 4 that the groove generally designated 24 may be on two levels so that a plunger pin, not shown, activated by the upper groove 24c can operate a steering gear lock pin while motion of the cylinder is controlled by the fixed pin 28 in bore 26 in the lock housing 12.
The pin 28 may be of the type that is driven into the bore 26 after assembly of the lock, thus rendering it impossible to remove the cylinder 16 without boring the pin 28 therefrom or the pin may be just a snug fit or be provided with threads which cooperate with threads in the bore 26 so that the pin 28 may be readily removed by a locksmith.
The cylinder housing 12 is provided with a counter-bore 30, which counter-bore rotatably receives a circular protector plate 38. The protector plate is provided with an opening 40 therethrough of a size to receive the entire shank portion 42 of the key 44 as more clearly shown in FIG. 2 of the drawing. The protector plate 38 has secured to the inner face 46 thereof a pair of guide pins 48, which guide pins are slidably received in a pair of bores 50 extending in a longitudinal direction in the lock cylinder 16 so that the protector plate 38 will rotate with the lock cylinder 16 and the lock cylinder 16 may be moved longitudinally in respect to the protector plate 38. The protector plate 38 prevents a lock picker from urging the cylinder 16 inwardly in respect to the housing 12 by inserting a tool in the opening in the cylinder housing and forcibly driving the cylinder inwardly against the restraining effect of the tumbler pins received in the bores 18a-18c, and 20a-20c.
The reduced diameter portion 50' of the protector plate 38 is received in the bore 52 in the cover 54 which slides over the lock housing 12, and which housing is free to rotate in respect to the protector plate 38 and the entire lock.
The assembly also includes a plate 56 which is bored as at 58 to abut the forward end 22 of the cylinder 16.
The plate 56 is also bored at 60 to receive a pair of threaded connectors 62 which threaded connectors engage with internal threads in bores 64 in the lock housing 12.
The plate 56 also engages one end 66 of a helical compression spring 66' while the other end 68 of the spring engages the shoulder 70 of the lock cylinder 16 and constantly urges the cylinder toward the front end 72 of the lock housing 12. In operation of the lock the operator via the key 44, as to be more fully described hereinafter, moves the cylinder 16 against the urging of the spring 66'.
The cylinder 16 is provided with an internal axially extending bore 73 which extends from end 74 to adjacent the plural level track 24b. Adjacent the track 24b the bore is conical in configuration as at 76 and the tip of the conical bore is intercepted by a counter-bore 78 in end of portion 22 of the cylinder. Of course, as shown more clearly in FIGS. 1 and 3, key receiving slots extend from the bores radially outwardly as at 80. The forward end of the bore 72 is closed by a plug 82 which plug is provided with the slots 84 for reception of the key 44.
The bore 78 receives a pair of rods 86 having in-turned ends 88. The in-turned ends of the rods 86 are adapted to the received-in the end slots 90a and 90b in the cone shaped end 92 of the key shank 44 when the key is fully inserted in the lock cylinder 16. Once the key is engaged by the in-turned ends 88 of the rods 86 inward motion of the cylinder 16, as to be more fully described hereinafter, causes the rods 86 to be urged inwardly for control of bolts or other locking mechanisms or the like.
With the conical end 76 of the bore 72, insertion of a pick lock into the cylinder would be of a little avail as the pick lock would be forced by the tapered walls of the conical end 76 to pass through the opening into the counter-bore 78 and inward pressure would fail to move the cylinder 16 against the urging of the coil spring 66'.
Referring now to FIG. 5 of the drawing a modified form of a lock constructed in accordance with the teachings of the present invention is illustrated wherein 10' depicts the lock, consisting of an outer housing or casing 54', a lock housing 12', a lock cylinder 16', and a winged actuator 17. The winged actuator 17 is connected to protector plate 38' which carries at its inner end a pair of pins 48' the ends of which are slidably received in bores 50', axially extending into the lock cylinder 16'. The protector plate 38' is provided with an angular groove 37 which groove receives the ends of screws or drive pins 39 whereby the protector plate 38' is free to rotate but can not be urged axially.
As in the prior form of the invention, the cylinder 16' has a bore 72' which terminates in a conical end 76' and the inner end of the conical bore 76' intersects a counter-bore 78' in the end or shank portion 22' of the cylinder 16'. Further, the lock assembly includes at least one set of cooperating bores and tumbler pin generally designated 35 and cooperating bores and pins 37 in the lock housing 12'.
The assembly also includes the rods 86' each having the in-turned end 88' which fit in lateral grooves in the tapered shank portion 92' of the key 44'.
The connection between the winged portion 17 and the protector plate 38' comprises a "joint of weakness" as at 19, whereby the lock cylinder 16' and the tumbler mechanism 35, 37, are positioned to permit rotation, however, a pick-lock attempting to rotate the lock cylinder 16' without a proper key 44' would shear the wing portion 17 from the protector plate 38' rendering the entire lock uncompromised but still in condition such that a proper party with the correct key 44' could cause the cylinder 16' to rotate the key itself.
Referring now to FIGS. 6 and 7, various arrangements of grooves 110 and 110' are illustrated. For example, the groove 110 has a longitudinal movement portion 112 and a pair of arcuate portions 114 and 116, which are engaged by bin 28 [to permit operation of plural bolts or electrical contacts or electric/hydraulic mechanisms as desired.] Groove 110' of the form of the cylinder illustrated in FIG. 7 includes a pair of parallel axially extending grooves 118 and 120 and a single acruate groove 122 interconnecting the pair of axial grooves 118 and 120. Again the nature and configuration of the grooves is substantially unlimited as the cylinders of the locks of the present invention are mounted for both the radial and axial motion.
Referring now to FIG. 8, there is illustrated a form of the invention wherein a portion of the cylindrical surface 150 of the lock cylinder 152 is provided with an elongated upstanding rib 154 which rib is engagement with an elongated groove 156 milled in the inner bore 158 of the lock housing.
The cylindrical surface 150 is also provided with milled longitudinal and radial groove structures indicated at 162 which cooperate with the inner end of pin 170. The upstanding rib 154 helps to insure that there is no rotary motion between the cylinder 152 and housing 160 until a predetermined amount of longitudinal or axial movement of the cylinder 152 relative to the housing 160. It will be appreciated that when the cylinder 152 has been urged axially relative to the housing 160 a distance such that end 172 clears the lateral extension of the milled groove 156 it would then be possible to rotate the cylinder 156 via the groove 162 as guided by the pin 170.
From the foregoing description various forms of my invention has been specifically disclosed. However, it will be recognized by those skilled in the art that other and various specific constructures may be substituted for those illustrated in the drawing without departing the scope of the present invention. | 4y
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TECHNICAL FIELD
This invention relates to resource handles and, in particular, to methods and systems for managing and resolving resource handles such that handle resolution can be performed without locking.
BACKGROUND
Resource handles are a common mechanism used in computer programming to name and reference resources. For example, an application programming interface (API) may use handles to reference resources that are exposed by the API to one or more clients. Resource handles provide a level of indirection between clients and the resources they use, which protects the resources from improper access by the clients.
When an API is invoked and is given a handle, it must resolve the handle in order to locate the actual resource that the handle represents. Typically, a handle is in some way associated with a pointer to a resource. Handle resolution is conceptually similar to locating a book within a library by using the title of the book to look up a unique number associated with the book, and then locating the book on the shelf using the number.
In systems with limited storage and processing capabilities, efficient resource handle management and resolution is especially important. Handles and their associated resolution information must be compact in order to consume minimal system memory, and the handle resolution process must be efficient. It is typical for a resource handle to be created once, and then resolved several times through calls to an API. As such, the performance of the handle resolution process can have a significant impact on the performance of a system as a whole.
Handle resolution information is typically stored in a variable length data structure. Due to the varying nature of such data structures, handle creation, deletion, and resolution processing requires that the data structure be locked. Locking the data structure provides mutually exclusive access to the data structure, which prevents multiple processing threads from attempting to modify the same 6 data structure at the same time, which may lead to corruption of the data structure.
Because handle resolution is performed with greater frequency than handle creation and deletion, it is desirable to be able to perform handle resolution without having to lock the resolution information data structures to ensure mutually exclusive access, as locking the resolution information data structures consumes processing time and can lead to additional latencies, context switching, and multi-thread synchronization overhead.
SUMMARY
A resource handle management technique for providing lock-free handle resolution is described. A hierarchical structure of handle mapping tables is dynamically resized as resource handles are created. A lowest level table, which stores indexed pointers to requested resources, is created first. As additional lowest level tables are added, higher level tables, which store indexed pointers to lower level tables, are added as needed. Resource handles are generated based on indices associated with one or more of the handle mapping tables. Once created, handle mapping tables are not deleted, and handle mapping tables are added to the hierarchical structure in such a way as to not affect concurrent handle resolution processing taking place for existing resource handles. Accordingly, handle resolution can be performed without having to lock the handle mapping tables.
BRIEF DESCRIPTION OF THE DRAWINGS
The same numbers are used throughout the drawings to reference like features and components.
FIG. 1 illustrates select components of an exemplary computer system in which lock-free handle resolution may be implemented.
FIG. 2 illustrates select components of an exemplary handle management system as depicted in FIG. 1 .
FIG. 3 illustrates a structure of an exemplary Level 1 handle mapping table.
FIG. 4 illustrates a structure of an exemplary two-level hierarchy of handle mapping tables.
FIG. 5 illustrates a structure of an exemplary three-level hierarchy of handle mapping tables.
FIG. 6 illustrates a structure of an exemplary resource handle.
FIG. 7 illustrates an exemplary method that may be performed by the handle creation/deletion manager of FIG. 2 .
FIG. 8 illustrates an exemplary method that may be performed by the handle resolution manager of FIG. 2 .
DETAILED DESCRIPTION
The following discussion is directed to methods and systems for managing and resolving resource handles. In the described example implementation, a hierarchical structure of handle mapping tables is created dynamically, based on requests for resource handles. The handle mapping tables are built one at a time, as needed, in a hierarchical fashion, beginning with child tables, and adding parent tables as needed. Handles are structured based on indexed locations associated with the created handle mapping tables. According to the described implementation, handle resolution is performed using the handle mapping tables without the need for table locking.
Exemplary System Architecture
FIG. 1 illustrates an exemplary computing system 102 that may be used to implement lock-free handle resolution. Computing system 102 includes processor 104 and memory 106 . Operating system 108 as well as other applications 110 are stored in memory 106 and executed on processor 104 .
Operating system 108 includes handle management system 112 , file system 114 , graphics system 116 , and may also include other subsystems 118 , such as a network system. Handle management system 112 performs tasks associated with creating, deleting, and resolving resource handles. Select components of handle management system 112 are described in more detail below with reference to FIG. 2 .
Exemplary Handle Management System
FIG. 2 illustrates select components of exemplary handle management system 112 illustrated in FIG. 1 . Handle management system 112 includes handle creation/deletion manager 202 , handle resolution manager 204 , and handle mapping tables 206 .
Handle creation/deletion manager 202 performs handle management tasks in response to receiving requests to create or delete resource handles. In the described implementation, in response to a request to create a resource handle, handle creation/deletion manager 202 may create one or more handle mapping tables 206 , store a pointer to a resource associated with the requested handle in handle mapping tables 206 , and generate a resource handle to be returned to the requesting application or process. An exemplary handle creation method that may be performed by handle creation/deletion manager 202 is described in more detail below with reference to FIG. 7 . In the described implementation, handles are formatted to indicate one or more indexed locations within handle mapping tables 206 . An exemplary handle structure is described in more detail below with reference to FIG. 6 .
In response to a request to delete a resource handle, handle creation/deletion manager 202 deletes the pointer to the resource associated with the handle from handle mapping tables 206 , thus rendering the resource handle invalid.
Handle resolution manager 204 is configured to receive a resource handle, and return a pointer to a resource associated with the received resource handle. Handle resolution manager 204 parses the received handle to identify indices associated with handle mapping tables 206 , which are used by handle resolution manager 204 to resolve the handle. An exemplary handle resolution method that may be performed by handle resolution manager 204 is described in more detail below with reference to FIG. 8 .
Handle mapping tables 206 are implemented as a dynamic hierarchy of tables. In the described implementation, the hierarchy may include up to three levels. Alternate implementations may be configured to allow more or fewer hierarchical levels while still enabling lock-free handle resolution. The Level 1 tables (also known as child nodes in a hierarchy) are used to store pointers to resources that are associated with resource handles. Level 2 tables (also known as parent nodes to the Level 1 child nodes) are used to store pointers to Level 1 tables. Similarly, Level 3 tables (also known as parent nodes to the Level 2 tables) are used to store pointers to Level 2 tables (which may then also be known as child nodes in relationship to the Level 3 tables). An exemplary structure of a three-level dynamic hierarchy of handle mapping tables 206 is described in more detail below with reference to FIGS. 3–5 .
Exemplary Handle Mapping Table Structure
FIGS. 3–5 illustrate an exemplary structure for handle mapping tables 206 . As described above, in an exemplary implementation, handle mapping tables 206 are implemented according to a dynamic hierarchy that may include up to three levels of table structures. FIG. 3 illustrates an exemplary single level handle mapping table structure; FIG. 4 illustrates an exemplary two-level handle mapping table structure; and FIG. 5 illustrates an exemplary three-level handle mapping table structure.
FIG. 3 illustrates an exemplary structure of a Level 1 handle mapping table 302 . As described above, each Level 1 handle mapping table 302 stores pointers to resources associated with resource handles. In the described implementation, each Level 1 handle mapping table 302 is configured to store pointers for up to 16 resource handles (indexed 0–15). Accordingly, a Level 1 table index may be represented by a 4-bit integer.
FIG. 4 illustrates an exemplary two-level hierarchy of handle mapping tables 206 . When a handle creation request is received after the first Level 1 handle mapping table 302 ( 1 ) is filled (i.e., 16 resource handles have been created), a second Level 1 handle mapping table 302 ( 2 ) is created to store a pointer to the resource associated with the new resource handle. In addition, a Level 2 handle mapping table 402 is created. The first entry in the Level 2 handle mapping table 402 stores a pointer to the first Level 1 handle mapping table 302 ( 1 ), and the second entry in the Level 2 handle mapping table 402 stores a pointer to the second Level 1 handle mapping table 402 ( 2 ). (In terms of the hierarchy, the Level 2 handle mapping table is now the parent table to the Level 1 handle mapping tables.)
As additional resource handles are created, additional Level 1 tables are added with pointers to the Level 1 tables being stored in Level 2 handle mapping table 402 . In the described implementation, each Level 2 handle mapping table is configured to store pointers for up to 64 Level 1 handle mapping tables (indexed 0–63). Accordingly, a Level 2 table index may be represented by a 6-bit integer.
FIG. 5 illustrates an exemplary three-level hierarchy of handle mapping tables 206 . When a handle creation request is received after the first Level 2 handle mapping table 402 ( 1 ) is filled (i.e., 64 Level 1 handle mapping tables have been filled), a new Level 1 handle mapping table 302 ( 65 ), a second Level 2 handle mapping table 402 ( 2 ), and a Level 3 handle mapping table 502 are created. The first entry in Level 1 handle mapping table 302 ( 65 ) stores a pointer to the resource associated with the new handle resource, and the first entry in Level 2 handle mapping table 402 ( 2 ) stores a pointer to the new Level 1 handle mapping table 302 ( 65 ). Level 3 handle mapping table 502 stores a pointer to the first Level 2 handle mapping table 402 ( 1 ) and a pointer to the second Level 2 handle mapping table 402 ( 2 ). (In terms of the hierarchy, the Level 3 handle mapping table is now the parent table to the Level 2 handle mapping tables.) In the described implementation, Level 3 handle mapping table 502 is configured to store pointers for up to 32 Level 2 handle mapping tables (indexed 0–31). Accordingly, a Level 3 table index may be represented by a 5-bit integer.
The number of indexed values that may be stored in each Level 1, Level 2, or Level 3 handle mapping table may be different in alternate implementations. Furthermore, alternate implementations may support more or fewer than three levels of handle mapping tables.
In the described implementation, when a request to delete a resource handle is received, the resource pointer associated with the handle is deleted from the appropriate Level 1 mapping table. The space made available when a resource pointer is deleted is re-used when a subsequent resource handle is requested. To enable lock-free handle resolution, handle mapping tables 206 are not deleted, even if all of the resource handles whose pointers are stored in a particular table are deleted. Because the handle resolution process does not require an exclusive lock on the handle mapping tables, it is possible that any number of processing threads may be accessing the handle mapping tables at any given time. If an existing handle mapping table were deleted, an existing handle resolution thread may be negatively impacted.
Exemplary Handle Structure
FIG. 6 illustrates a structure of an exemplary resource handle 600 . In the described implementation, each resource handle is represented as a 32-bit integer that includes three handle mapping table indices 602 , 604 , and 606 . When a handle is created, the bits that make up a Level 1 handle mapping table index 602 (e.g., bits 0 – 3 ) are set to a value that represents the index of the Level 1 handle mapping table in which the pointer to the resource associated with the handle is stored. For example, bits 0 – 3 of a handle whose pointer is stored at index 1 of a Level 1 handle mapping table 504 will have the value “0001”, while bits 0 – 3 of a handle whose pointer is stored at index 14 of a Level 1 handle mapping table will have the value “1110”.
When a handle is created, the bits that make up a Level 2 handle mapping table index 604 (e.g., bits 4 – 9 ) are set to a value that represents the index of the Level 2 handle mapping table that points to the Level 1 handle mapping table in which the pointer to the resource associated with the handle is stored. If, when the handle is created, there is no Level 2 handle mapping table, then the bits of the Level 2 handle mapping table index 604 are all set to 0. Because of the way handle mapping tables are created such that the first entry in a Level 2 table points to the first created Level 1 table, a Level 2 handle mapping table index 604 of 0 is assured to be accurate even after a Level 2 handle mapping table is created.
Similarly, when a handle is created, the bits that make up a Level 3 handle mapping table index 606 (e.g., bits 10 – 14 ) are set to a value that represents the index of the Level 3 handle mapping table that points to the Level 2 handle mapping table that includes an indexed pointer to the Level 1 handle mapping table in which the pointer to the resource associated with the handle is stored. If, when the handle is created, there is no Level 3 handle mapping table, then the bits of the Level 3 handle mapping table index 606 are all set to 0.
In alternate implementations, the size of each Level 1, Level 2, and Level 3 mapping table may differ from the described implementation. The number of bits in each resource handle that correspond to the Level 1, Level 2, and Level 3 handle mapping table indices may also differ accordingly.
In an alternate implementation, handle 600 also includes one or more bits (e.g., bits 26 – 31 ) that are designated as a handle set indicator. A handle set indicator may be used to identify a particular group of handle mapping tables associated, for example, with an operating system sub-system. For example, resource handles associated with file system 114 may all be associated with the same handle set identifier and may be managed using one dynamic three-level hierarchy of handle mapping tables 206 . Similarly, resource handles associated with graphics system 116 may all be associated with another handle set identifier and may be managed using another dynamic three-level hierarchy of handle mapping tables 206 .
The number of bits that are designated as a handle set identifier may vary in alternate implementations, depending on the number of handle sets to be supported. For example, two bits may be used to designate up to four handle sets, while three bits may be used to designate up to eight handle sets. In an exemplary implementation, bits 26 – 31 are used, supporting up to 64 handle sets.
Exemplary Handle Management Methods
Resource handle management may be described in the general context of computer-executable instructions, such as application modules, being executed by a computer. Generally, application modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Handle management system 112 may be implemented using any number of programming techniques and may be implemented in local computing environments or in distributed computing environments where tasks are performed by remote processing devices that are linked through various communications networks based on any number of communication protocols. In such a distributed computing environment, application modules may be located in both local and remote computer storage media including memory storage devices.
Exemplary Handle Creation Method
FIG. 7 illustrates an exemplary method 700 that may be performed by handle creation/deletion manager 202 to create a resource handle.
At block 702 , handle creation/deletion manager 202 receives a request for a resource handle.
At block 704 , handle creation/deletion manager 202 determines whether or not a Level 1 handle mapping table exists. If it is determined that a Level 1 handle mapping table does not exist (indicating that there are no resource handles currently being managed), then a new Level 1 handle mapping table is created at block 722 (the “No” branch from block 704 ), which is described in more detail below.
On the other hand, if it is determined that a Level 1 handle mapping table does exist (the “Yes” branch from block 704 ), the handle creation/deletion manager 202 determines whether or not all of the existing Level 1 handle mapping tables are full (block 706 ). If there is at least one Level 1 handle mapping table that is not full (the “No” branch from block 706 ), a pointer to the requested resource is stored in a Level 1 handle mapping table at block 724 , described in more detail below.
On the other hand, if it is determined that all existing Level 1 handle mapping tables are full (the “Yes” branch from block 706 ), then handle creation/deletion manager 202 determines whether or not a Level 2 handle mapping table exists (block 708 ). If it is determined that a Level 2 handle mapping table does not exist (the “No” branch from block 708 ), then a Level 2 handle mapping table is created at block 720 , described below.
On the other hand, if it is determined that a Level 2 handle mapping table does exist (the “Yes” branch from block 708 ), then at block 710 , handle creation/deletion manager 202 determines whether or not all of the existing Level 2 handle mapping tables are full. If there is at least one Level 2 handle mapping table that is not full (the “No” branch from block 710 ), then a pointer to the requested resource is stored in a Level 1 handle mapping table at block 724 , described in more detail below. On the other hand, if it is determined that all existing Level 2 handle mapping tables are full (the “Yes” branch from block 710 ), then at block 712 , handle creation/deletion manager 202 determines whether or not a Level 3 handle mapping table exists. If it is determined that a Level 3 handle mapping table does not exist (the “No” branch from block 712 ), then a new Level 3 handle mapping table is created at block 718 .
On the other hand, if it is determined that a Level 3 handle mapping table does exist (the “Yes” branch from block 712 ), then at block 714 , handle creation/deletion manager 202 determines whether or not the existing Level 3 handle mapping table is full. If the Level 3 handle mapping table is not full (the “No” branch from block 714 ), then a pointer to the requested resource is stored in a Level 1 handle mapping table at block 724 .
On the other hand, if it is determined that the existing Level 3 handle mapping table is full (the “Yes” branch from block 714 ), then at block 716 an error value is returned indicating that there is no space available to create the requested resource handle, and processing stops.
At block 718 , handle creation/deletion manager 202 creates a new Level 3 handle mapping table. A pointer to the first Level 2 mapping table is stored in the newly created Level 3 handle mapping table at index 0. (Because of the order in which handle mapping tables are created, there is guaranteed to be one and only one Level 2 handle mapping table when a Level 3 handle mapping table is created.)
At block 720 , handle creation/deletion manager 202 creates a new Level 2 handle mapping table. If this is the first Level 2 handle mapping table, then a pointer to the first Level 1 mapping table is stored in the newly created Level 2 handle mapping table at index 0. (Because of the order in which handle mapping tables are created, there is guaranteed to be one and only one Level 1 handle mapping table when the first Level 2 handle mapping table is created.) If this is not the first Level 2 handle mapping table, then a pointer to the newly created Level 2 handle mapping table is stored at the next available index in the Level 3 handle mapping table.
At block 722 , handle creation/deletion manager 202 creates a new Level 1 handle mapping table. If this is not the first Level 1 handle mapping table, then a pointer to the newly created Level 1 handle mapping table is stored in the next available index in a Level 2 handle mapping table.
At block 724 , handle creation/deletion manager 202 stores a pointer to the requested resource in the first available index in a Level 1 handle mapping table.
At block 726 , handle creation/deletion manager 202 determines a Level 1 index value, a Level 2 index value, and a Level 3 index value. The Level 1 index value is the index of the resource pointer within the Level 1 handle mapping table, as described above with reference to block 724 .
If one or more Level 2 handle mapping tables exist, then the Level 2 index value is the index of the Level 2 handle mapping table that stores a pointer to the Level 1 handle mapping table in which the resource pointer is stored. On the other hand, if no Level 2 handle mapping tables exist, then the Level 2 index value is set to zero.
If a Level 3 handle mapping table exists, then the Level 3 index value is the index of the Level 3 handle mapping table that stores a pointer to the Level 2 handle mapping table that stores a pointer to the Level 1 handle mapping table in which the resource pointer is stored. On the other hand, if no Level 3 handle mapping table exists, then the Level 3 index value is set to zero.
At block 728 , handle creation/deletion manager 202 returns a 32-bit resource handle to the requesting application or process. The handle is formatted to include the Level 1, Level 2, and Level 3 index values, as described above with reference to FIG. 6 . In an alternate implementation, the resource handle may also be formatted to indicate a handle set, which is also described above with reference to FIG. 6 . Furthermore, although illustrated and described as a 32-bit value, in alternate implementations, the resource handle may have a different size, for example, 16 or 64 bits. As such, the number of hierarchical levels that are supported as well as the number of values stored in each of the handle mapping tables on each level may also differ.
Because the hierarchical structure of the handle mapping tables may change with the creation of a new resource handle, handle mapping tables 206 are locked during the handle creation processing described above with reference to FIG. 7 , to ensure mutually exclusive access to the tables.
Exemplary Handle Resolution Method
When handle management system 112 receives a resource handle, handle resolution manager 204 uses handle mapping table 206 to locate a pointer associated with the received resource handle. The handle management system 112 then returns a pointer to the resource to the application or process from which it received the resource handle.
FIG. 8 illustrates an exemplary method 800 that may be performed by handle resolution manager 204 to resolve a resource handle.
At block 802 , handle resolution manager 204 receives a resource handle.
At block 804 , handle resolution manager 204 parses the received resource handle to determine the associated Level 1, Level 2, and Level 3 index values. In the described implementation, the Level 1 index value is based on the values of bits 0 – 3 ; the Level 2 index value is based on the values of bits 4 – 9 ; and the Level 3 index value is based on the values of bits 10 – 14 . In an alternate implementation, handle resolution manager 204 also parses the received resource handle to determine the handle set identifier (e.g., based on the values of bits 26 – 31 ), which is then used to determine which set of handle mapping tables 206 is associated with the received handle. As described above, in alternate implementations, the number of bits associated with each index value or with a handle set identifier may differ from those in the described implementation.
At block 806 , handle resolution manager 204 determines whether or not a Level 3 handle mapping table exists. If a Level 3 handle mapping table does not exist (the “No” branch from block 806 ), then handle resolution manager 204 determines whether or not a Level 2 handle mapping table exists, as described in more detail below with reference to block 812 .
On the other hand, if a Level 3 handle mapping table does exist (the “Yes” branch from block 806 ), then at block 808 , handle resolution manager 204 finds a pointer to a resource based on the Level 3 index value (which was identified as described above with reference to block 804 ). Handle resolution manager 204 locates the position in the Level 3 handle mapping table that corresponds to the Level 3 index value. That position holds a pointer to a Level 2 handle mapping table. Handle resolution manager 204 then locates the position in the identified Level 2 handle mapping table that corresponds to the Level 2 index value. That position holds a pointer to a Level 1 handle mapping table. Handle resolution manager 204 then locates the position in the identified Level 1 handle mapping table that corresponds to the Level 1 index value. That position holds a pointer to a resource.
At block 810 , handle resolution manager 204 returns the identified resource pointer to the requesting application or process.
At block 812 (if it is determined at block 806 that a Level 3 handle mapping table does not exist), handle resolution manager 204 determines whether or not a Level 2 handle mapping table exists. If a Level 2 handle mapping table does not exist (the “No” branch from block 812 ), then handle resolution manager 204 determines whether or not a Level 1 handle mapping table exists, as described in more detail below with reference to block 818 .
On the other hand, if a Level 2 handle mapping table does exist (the “Yes” branch from block 812 ), then at block 814 , handle resolution manager 204 finds a pointer to a resource based on the Level 2 index value (which was identified as described above with reference to block 804 ). Handle resolution manager 204 locates the position in the Level 2 handle mapping table that corresponds to the Level 2 index value. That position holds a pointer to a Level 1 handle mapping table. Handle resolution manager 204 then locates the position in the identified Level 1 handle mapping table that corresponds to the Level 1 index value. That position holds a pointer to a resource.
At block 816 , handle resolution manager 204 returns the identified resource pointer to the requesting application or process.
At block 818 (if it is determined at block 812 that a Level 2 handle mapping table does not exist), handle resolution manager 204 determines whether or not a Level 1 handle mapping table exists. If a Level 1 handle mapping table does not exist (the “No” branch from block 818 ), then at block 820 , handle resolution manager 204 returns an error, indicating that no resource handles are currently being managed.
On the other hand, if a Level 1 handle mapping table does exist (the “Yes” branch from block 818 ), then at block 822 , handle resolution manager 204 finds a pointer to a resource based on the Level 1 index value (which was identified as described above with reference to block 804 ). Handle resolution manager 204 locates the position in the Level 1 handle mapping table that corresponds to the Level 1 index value. That position holds a pointer to a resource.
At block 824 , handle resolution manager 204 returns the identified resource pointer to the requesting application or process.
Because individual handle mapping tables are not deleted after they are created, and because initial Level 2 and Level 3 index values are predetermined to be zero, even before the first Level 2 or Level 3 mapping table is created, mutually exclusive access to handle mapping tables 206 is not required during the handle resolution processing described above with reference to FIG. 8 . Accordingly, FIG. 8 illustrates a method for performing lock-free handle resolution, which results in decreased processing time, and thus increased system performance.
CONCLUSION
Although the systems and methods have been described in language specific to structural features and/or methodological steps, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific features or steps described. Rather, the specific features and steps are disclosed as preferred forms of implementing the claimed invention. | 4y
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BACKGROUND OF THE INVENTION
This invention relates to the palladium-catalyzed deprotection of allylic esters and ethers.
It is well known to use the allyloxycarbonyl group as a protecting group for a carboxylic acid, i.e., to esterify the carboxylic acid with allyl alcohol and to thereafter remove the allyloxycarbonyl group to convert the carboxylic acid group back to its original form after it has served its protecting function. For example, Ohtani et al in Journal of Organic Chemistry, 1984, Vol. 49, pps. 5271-5272, report that one crucial step in the synthesis of carbapenems is the final deprotection step of the C-3 ester function and cite as one example the cleavage of the allyl ester group by the action of palladium(0).
The following references all disclose cleavage of the allyloxycarbonyl function in carboxyl protected betalactam derivatives, such as penicillins, cephalosporins, and carbapenems, using potassium 2-ethylhexanoatein the presence of a catalytic amount of tetrakis(triphenylphosphine)-palladium(0) and triphenylphosphine:
Jeffrey et al, Journal of Organic Chemistry, 1982, Vol. 47, pps. 587-590;
U.S. Pat. No. 4,314,942;
U.K. Pat. appln. No. GB 2 128 187A, published Apr. 26, 1984, Example 21.
Kunz et al, Angew. Chem. Int. Ed. Engl., 1984, Vol. 23, pps. 71-72 report on the use of the allyl group as a removable carboxy-protecting group for the synthesis of labile O-glycopeptides. This article reports on the cleavage of the allyl ester moiety by reaction with about ten mole percent of tetrakis(triphenylphosphine)palladium(0) under argon in tetrahydrofuran and in the presence of a ten fold excess of morpholine as an acceptor nucleophile.
It is an object of this invention to provide a process for the deallylation of allyl esters and phenolic ethers which results in higher yields of the corresponding carboxylic acid or phenol then prior art processes.
It is a further object of this invention to provide such a process which can be conducted at lower temperatures and in shorter reaction times than prior art processes, thereby making possible its application to allyl esters having sensitive structural features that might be decomposed under reaction conditions involving higher temperatures and longer reaction times.
SUMMARY OF THE INVENTION
The objects of this invention are attained by a process which comprises reacting an allyl ester of a carboxylic acid or an allyl ether of a phenol with pyrrolidine or piperidine and a catalytic amount of an organic-soluble palladium complex having a coordinating phosphine ligand to cleave the allyl moiety. The resultant carboxylic acid or phenol is then recovered.
DETAILED DESCRIPTION OF THE INVENTION
The process of this invention may be utilized for the deallylation of any allyl ester of a carboxylic acid or allyl ether or a phenol, e.g., allylphenyl ether, the allyl ester of benzoic acid, the allyl ester of cinnamic acid, etc. A preferred class of allyl esters which may be deprotected in accordance with the practice of this invention, are beta-lactam allyl esters such as penicillins, cephalosporins, and carbapenems. Particularly preferred are allyl esters of carbapenem derivatives, said derivatives being characterized by a 2-substituent of the formula ##STR1## in which A represents a C 1 -C 6 straight or branched chain alkylene group; R 1 represents an optionally substituted aliphatic, cycloaliphatic, cycloaliphatic-aliphatic, aryl, araliphatic, heteroaryl, heteroaraliphatic, heterocyclyl or heterocyclyl-aliphatic radical and ##STR2## represents a nitrogen-containing aromatic heterocycle attached to the alkylene group A at a ring carbon atom and quanternized by substituent R 1 . Such derivatives are described in detail in U.K. patent application No. GB No. 2 128 187A, the disclosure of which is incorporated herein by reference.
The preferred organic-soluble palladium complex catalyst useful in the process of this invention is tetrakis(triphenylphosphine)palladium(0) and it is preferably utilized in the presence of free triphenylphosphine. It is preferred to use from 0.01 to 0.1 mole of catalyst per mole of allyl ester or ether. It is also preferred to use from 1.5 to 5 moles of triphenylphosphine per mole of tetrackis(triphenylphosphine)palladium.
The amount of pyrrolidine or piperidine used in the reaction is preferably from 1.0 to 1.5 moles per mole of allyl ester or ether.
The deallylation reaction is preferably conducted in an inert solvent such as dichloromethane, chloroform, ethyl ether, benzene, toluene, ethyl acetate, acetonitrile, etc. It is preferred to conduct the reaction at a temperature of from -5° C. to 30° C. for a time of from 10 minutes to 4 hours.
The following examples illustrate the best modes contemplated for carrying out this invention. ##STR3##
Methyl trifluoromethanesulfonate (1.05 equivalent) was added to an ice cooled suspension of compound I, obtained as described in Step F, Example 21 of U.K. patent application No. GB 2128187A, in acetonitrile. After 20 minutes, triphenylphosphine (5% mole), tetrakis(triphenylphosphine)palladium(0) (2.5% mole) and pyrrolidine (1.05 equivalent) were added. Precipitation occurred rapidly and the resulting slurry was stirred for 10 minutes at 0° C. After adding acetone, the crude solid was isolated and crystallized from methanol to give the desired product, II, in 70% yield and with 90-93% purity.
When potassium 2-ethylhexanoate is substituted for pyrrolidine in Example 1, no product is obtained.
EXAMPLE 2 ##STR4##
A solution of the allyl ester, compound III, (0.350 g, 0.936 mmol) in 6 mL of dry acetonitrile was cooled at -5° C. and treated with methyl trifluoromethanesulfonate (0.111 mL, 0.983 mmol). After 15 minutes, a solution of tetrakis(triphenylphosphine)palladium (0.027 g, 25 mol %) and triphenylphosphine (0.027 g) was added. After stirring the reaction mixture for 5 minutes, pyrrolidine (0.082 mL, 0.983 mmol) was added dropwise. A solid slowly began to separate from the resulting brown solution. The mixture was vigorously stirred at 0° C. for 20 minutes, then 15 mL of cold (0° C.) acetone was slowly added and stirring was continued at 0° C. for 20 minutes. The resulting suspension was filtered and the residue was washed with cold acetone and then dried to vacuo to give 0.345 g of a beige powder. This material was taken up in a small amount of pH 7 phosphate buffer (0.05 M) and applied to a short reverse-phase (C 18 BondaPak) column. Elution with H 2 O and lyophilization of the relevant fractions gave 0.255 g of a light yellow solid. This material was rechromatographed, as done before, to afford (after lyophilization) pure compound IV (0.195 g, 60% yield) as a light yellow solid: 1 Hnmr (D 2 O) δ8.58, 7.83 (ABq, J=6.4 Hz, 2H), 7.87 (s, 1H), 4.32-3.95 (m, 2H), 4.22 (s, 2H), 4.17 (s, 3H), 3.32 (dd, J 1 =2.6 Hz, J 2 =6.1 Hz, 1H), 3.06-2.93 (m, 2H), 2.74 (s, 3H), 1.22 (d, J=6.4 Hz, 3H); ir (KBr) 1757, 1590 cm -1 ; uv (phosphate buffer, pH 7.4) 296 nm (ε7446).
EXAMPLE 3 ##STR5##
A solution of the allyl ester, compound V, (0.582 g, 0.0015 mol) in 15 mL of dry acetonitrile was treated with methyl trifluoromethanesulfonate (0.178 mL, 1.575 mmol) at -5° C. under N 2 . After 15 minutes, a solution of tetrakis(triphenylphosphine)palladium (0.035 g, 2 mol %) and triphenylphosphine (0.035 g) in 1 mL of methylene chloride was added, followed after 5 minutes by 0.131 mL (1.575 mmol) of pyrrolidine. The resulting mixture was stirred at 0° C. for 20 minutes and then 30 mL of cold (0° C.) acetone was added. The mixture was vigorously stirred at 0° C. for 15 minutes and then the precipitate was collected by filtration, washed with cold acetone and dried in vacuo to give 0.520 g of a beige powder. By diluting the filtrate with ether, another 0.041 of the crude product was obtained. The combined solids were dissolved in a small about of pH 7.4 phosphate buffer (0.05M) and applied to a reverse-phase (C 18 BondaPak) column. Elution with H 2 O and then 2% acetonitrile-H 2 O afforded, after lyophilization, compound IV (0.413 g, 76% yield) as a yellow solid: 1 Hnmr (D 2 O) δ8.55, 7.76 (ABq, J=6.3 Hz, 2H), 7.81 (s, 1H), 4.4-3.7 (m, 2H), 4.19 (s, 2H), 4.16 (s, 3H), 3.47-3.14 (m. 2H), 2.73 (s, 3H), 1.24 (d, J=6.4 Hz, 3H), 1.16 (d, J=7.3 Hz, 3H), ir (KBr) 1750, 1595 cm -1 ; uv (phosphate buffer, pH 7.4) 293 nm (ε7170).
EXAMPLE 4 ##STR6##
To an ice-cooled suspension of the allyl ester, compound VII (10.00 g, 26.7 mmol) in 100 mL of acetonitrile was added methyl trifluoromethanesulfonate (3.17 mL, 28.05 mmol). The resulting homogeneous yellow solution was stirred at 20° C. Triphenylphosphine (350 mg, 1.33 mmol) and tetrakis(triphenylphosphine)palladium (770 mg, 0.66 mmol) in 20 mL of methylene chloride were succissively added, the mixture was stirred 5 minutes and then a solution of pyrrolidine (2.4 mL, 28.05 mmol) in 15 mL of acetonitrile was added over a 5 minutes period. Crystallization occurred and the resulting slurry was stirred at 0° C. for 10 minutes. Pre-cooled acetone (150 mL) was added and the mixture was stirred 15 minutes. The resultant yellow solid was collected and washed twice with 60 mL of acetone. After drying, the yellow solid was triturated in 50 mL of cold (0° C.) methanol for 30 minutes. The resultant beige paste was filtered, partially dried, and dissolved in 20 mL of cold water. The resulting mixture was filtered quickly and 100 mL of cold ethanol were added. After stirring at 0° C. for about 10 minutes, crystallization occurred and the resulting mixture was stirred 1.3 hours more. The solid was collected and dried under high vacuum for 3 hours to obtain compound VIII, 4.82 g, 51.8% yield.
EXAMPLE 5 ##STR7##
A solution of the allyl ester, compound IX (12.63 g, 33.707 mmol) in 124 mL of acetonitrile was treated at 0°-5° C. under a nitrogen atmosphere by adding dropwise methyl trifluoromethanesulfonate (4.055 mL, 35.349 mmol). The clear yellow reaction mixture was stirred for 15 minutes at 0°-5° C. To this reaction mixture maintained at 0°-5° C. was added at once triphenylphosphine (429.44 mg, 1.661 mmol), followed by a solution of tetrakis(triphenylphosphine)palladium (959.56 mg 0.831 mmol) in 33 mL of methylene chloride. The clear orange reaction mixture was stirred at 0°-5° C. for 5 minutes. There was then added dropwise a solution of pyrrolidine (3.03 mL, 33.707 mmol) in acetonitrile (41.3 mL). To this clear dark orange reaction mixture, which was stirred 5 minutes at 0°-5° C., was added, portion wise and with vigorous stirring, ice-cold acetone (250 mL) followed by anhydrous diethyl ether (150 mL). Stirring was continued for 5 minutes at 0°-5° C., and the suspension was then filtered quickly under a stream of nitrogen. The solid residue was washed with anhydrous diethyl ether (50 mL) and vacuum dreied to obtain 11.05 g (33.12 mmol, yield 96.6%) of compound X as a crude yellow hygroscopic solid. The solid was dissolved in ice-cold phosphate buffer (75 mL; pH 7.0) and was washed twice with 50 mL portions of diethyl ether. The aqueous layer was vacuum pumped with stirring for 45 minutes and was purified by reversed phase chromotography. After purification and lyophilization, 9.63 g (27.617 mmol, yield 81.0%) of compound X was obtained.
EXAMPLES 6 AND 7 ##STR8##
Utilizing procedures similar to those described in Examples 1-5, the above reactions were conducted. Compound XII was obtained in a 72% yield and Compound XIV was obtained in a 61% yield.
The following example illustrates the use of piperidine instead of pyrrolidine in the practice of this invention.
EXAMPLE 8
The reaction illustrated in Example 1 was conducted as follows: To a suspension of the allyl ester, compound I (350 mg, 0.971 mmol) in 10 mL of acetonitrile, cooled to 0° C., was added methyl trifluoromethanesulfonate (0.121 mL, 1.068 mmol). The resulting light yellow mixture was stirred 1 hour and triphenylphosphine (25 mg, 0.095 mmol) and tetrakis(triphenylphosphine)palladium (25 mg, 0.0216 mmol) in 2 mL of methylene chloride were added. Piperidine (0.105 mL, 1.068 mmol) was slowly added and the resulting light orange mixture was stirred at 0° C. After 15 minutes, a yellow precipitate formed and stirring was continued for 11/2 hours. Acetone (10 mL) was added and the resulting slurry was stirred 30 minutes, the solid was filtered and washed with two 10 mL portions of acetone and dried. The resultant product, 230 mg, 70.7% yield, had a purity of about 69.4%.
The following example illustrates the process of this invention applied to the deallylation of a cephalosporin.
EXAMPLE 9 ##STR9##
To an ice-cooled solution of the allyl ester, compound XV (787 mg, 1.828 mmol), tetrakis(triphenylphosphine)palladium(0) (53 mg, 0.045 mmol) and triphenylphosphine (50 mg, 0.190 mmol) in 10 mL of methylene chloride was slowly added pyrrolidine (0.161 mL, 1.919 mmol). The mixture was stirred at 0° C. for 25 minutes and was then poured into 10 mL of a diluted solution of sodium bicarbonate (383 mg). After vigorous agitation, the organic phase was separated and extracted again with 10 mL of diluted sodium bicarbonate. The aqueous solution was then acidified to pH 2.5 at 0° C. with 1N HCl to which 10 mL of methylene chloride had been previously added. The organic phase was separated and the aqueous solution was extracted with another 10 mL of methylene chloride. After drying and evaporation in vacuo, 630 mg of the free acid, compound XVI, was obtained (88% yield).
The following two examples illustrate the deallylation process applied to allyl esters of penicillins.
EXAMPLE 10
To an ice-cooled mixture of the allyl ester of penicillin-V (540 mg, 1.38 mmol) and tetrakis(triphenylphosphine)palladium (40 mg, 0.0345 mmol) in 10 mL of methylene chloride was added pyrrolidine (0.121 mL, 1.45 mmol). The mixture was stirred at 0° C. for 30 minutes and then extracted with 10 mL of aqueous sodium bicarbonate (600 mg). The solution was then acidified with 5 HCl and extracted portions of methylene chloride. After drying and evaporation in vacuo, 301 mg (62.3% yield) of penicillin-V free acid was isolated as a white solid. The NMR spectrum was consistent with the structure of penicillin-V free acid.
EXAMPLE 11
To a solution of the allyl ester of penicillin-G (1.456 g; 3.889 mmol) in 20 mL of methylene chloride were added tetrakis(triphenylphosphine)palladium (112 mg, 0.097 mmol) and triphenylphosphine (100 mg, 0.381 mmol). After stirring a few minutes, a homogeneous mixture was obtained. The mixture was then cooled down to 0° C. and pyrrolidine (0.341 mL, 4.084 mmol) in 5 mL of methylene chloride was added slowly. The resulting mixture was stirred 15 minutes at 0° C. Diluted sodium bicarbonate (25 mL), prepared by dissolving 1.63 g of sodium bicarbonate in 50 mL of water, and 10 mL of ethyl acetate were added. After vigorous stirring, the aqueous protion was collected. The organic phase was extracted with 25 mL of diluted sodium bicarbonate. The combined aqueous phases were cooled to 0° C., 20 mL of methylene chloride were added and the mixture was acidified to pH 2 with 5% HCl (about 14 mL). The organic phase was collected and the aqueous mixture was extracted with two 25 mL portions of methylene chloride. The combined organic phases were dried, then concentrated in vacuo to give 1.22 g (93.8% yield) of white solid penicillin-G free acid. The NMR spectrum was consistent with the structure of penicillin-G free acid.
The following two examples illustrate the process of this invention applied to the deallylation of simple aromatic acids.
EXAMPLE 12
To an ice-cooled solution of the allyl ester of benzoic acid (1.00 g, 6.16 mmol) in 15 mL of methylene chloride was added tetrakis(triphenylphosphine)palladium (178 mg, 0.154 mmol). The reaction mixture was stirred until a homogenous solution was obtained. Pyrrolidine (0.540 mL, 6.47 mmol) was added and the resulting mixture was stirred 20 minutes at 0° C., the poured into 20 mL of diluted sodium hydroxide (285 mg NaOH, 7.12 mmol). The organic phase was decanted and the aqueous solution was washed with 5 mL of methylene chloride. After acidification with 5% HCl (about 6 mL) the benzoic acid produce was extracted with methylene chloride using three 10 mL portions. After drying and concentration in vacuo, there were obtained 730 mg (97% yield) of benzoic acid which was isolated as a white solid having a melting point of 122°-123° C.
EXAMPLE 13
To an ice-cooled solution of the allyl ester of trans cinnamic acid (1.0 g, 5.31 mmol) and tetrakis(triphenylphosphine)palladium(0) (150 mg, 0.13 mmol) in 15 mL of methylene chloride was added pyrrolidine (0.466 mL, 5.58 mmol). The resulting mixture was stirred at 0° C. for 50 minutes. It was then poured into 20 mL of diluted sodium hydroxide (5.86 mmol NaOH), the aqueous phase was washed with two 15 mL portions of methylene chloride, then acidified with diluted 5% HCl. The acid was extracted with three 10 mL portions of methylene chloride. The organic phase was then dried over magnesium sulfate and evaporated in vacuo to give 765 mg (97.2% yield) of trans cinnamic acid having a melting point of 133°-134° C. The NMR spectrum was consistent with the structure of trans cinnamic acid.
The following example illustrates the deallylation of the allyl ether of phenol.
EXAMPLE 14
To a solution of allylphenyl ether (1.00 g, 7.45 mmol) in 10 mL of methylene chloride were added tetrakis(triphenylphosphine)palladium(0) (215 mg, 0.186 mmol), triphenylphosphine (215 mg, 0.819 mmol) and pyrrolidine (0.684 mL, 8.198 mmol). The mixture was stirred at room temperature for 4 hours. The reaction mixture was extracted with two 10 mL portions of 5% aqueous sodium hydroxide, and the extracts were acidified with concentrated HCl to a pH of about 1-2. The phenol was extracted with three 10 mL portions of methylene chloride, dried over magnesium sulfate and filtered. After concentration in vacuo, there were obtained 625 mg (89.1% yield) of pure phenol. The NMR spectrum was consistent with the structure of phenol. | 4y
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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0001] No federal government funds were used in researching or developing this invention.
CROSS REFERENCE TO RELATED APPLICATIONS
[0002] This patent application claims priority to European Patent Application 12 191 662.1, filed on Nov. 7, 2012.
NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT
[0003] Not applicable.
SEQUENCE LISTING INCLUDED AND INCORPORATED BY REFERENCE HEREIN
[0004] Not applicable.
BACKGROUND
[0005] 1. Field of the Invention
[0006] The invention relates to a drive of a seat adjusting device for motor vehicles with a spindle that is fastened on a first of two rails, which can be adjusted relative to each other, by means of at least one mounting located on one end of the spindle and with a motor-driven transmission that is arranged on the second rail.
[0007] Such a drive is described in EP 1 068 093 B1. The drive is shown in the figure there and in the present FIG. 1 . As can be seen, a retaining plate 1 on which the seat of the vehicle is to be fastened is assigned to an upper rail 3 . On the retaining plate 1 , mounting links 11 are provided for a motor 2 so that it can be tightly connected to the retaining plate 1 and thus tightly connected to the upper rail. On both sides of motor 2 , drive shafts 21 , 22 are arranged. Flexible shafts can be used for this. These drive shafts 21 , 22 produce the connection to a transmission 9 that is described in detail in EP 1 068 093 B1.
[0008] The upper rail 3 glides directly, or over, adjusting and/or bearing elements that are not shown on a lower rail 4 that is fastened on a vehicle floor of the motor vehicle.
[0009] In the functional positions of upper rail 3 and lower rail 4 , these are held by their contact and/or mounting areas so that a hollow space results. Inside this hollow space, a threaded spindle 5 is arranged. This threaded spindle 5 is held by mountings 6 a and 6 b , which are tightly mounted on the lower rail 4 . For this purpose, the mountings 6 a and 6 b have fastener holes 6 e through which suitable threaded connections or similar fasteners extend and are held on fastener holes 4 a of the lower rail 4 . The spindle 5 itself is bolted tightly on the mountings 6 a and 6 b using suitable fastening nuts 6 c , 6 d.
[0010] What is problematic in the drive shown in FIG. 1 is the design of the mountings 6 a and 6 b.
[0011] These mountings 6 a , 6 b designed with an L-shape are ordinarily manufactured as stamped bent parts. In this case, the mountings are first punched out of metal plates as strip-shaped elements and then bent in a right angle. In fact, such stamped bent parts are relatively easy to manufacture and are thus cost-effective. However, the strength of these mountings, which is too low, is a disadvantage. In fact, such stamped bent parts can absorb only limited forces in the case of a crash. In tests, it has been found that such stamped bent parts can handle relatively low forces of up to about 20 kN in the case of a crash.
BACKGROUND OF THE INVENTION
[0012] The current state of knowledge is as follows.
[0013] The goal of the invention is to further develop the known drive in such a way that in the case of a crash, higher forces can be absorbed by the mounting or mountings than were previously possible.
[0014] This goal is achieved by a drive as claimed herein.
BRIEF SUMMARY OF THE INVENTION
[0015] In a preferred embodiment, a drive of a seat adjusting device, especially for motor vehicles, comprising a spindle that is fastened on a first of two rails, which are adjustable with respect to each other, by means of a mounting located at the end of the spindle and with a transmission driven by a motor that is mounted on the second rail, further comprising wherein the mounting has one part as a base plate, from which two walls at a distance from each other extend upward and that at least one end of the spindle is fastened between these two walls.
[0016] In another preferred embodiment, the drive as disclosed, further comprising wherein the walls have at least approximately half the length of the base plate.
[0017] In another preferred embodiment, the drive as disclosed, wherein the two walls are two longitudinal legs of a U-strap, the base plate has two slots at a distance from each other that run at least approximately concentric to a spindle axis of the spindle and the two longitudinal legs of U-strap are slid from below the base plate through the slots such that a transverse leg of the U-strap is in contact with the underside of the base plate.
[0018] In another preferred embodiment, the drive as disclosed, further comprising wherein the base plate has a recess on its underside, in which the transverse leg of the U-strap engages so the mounting has an at least approximately flat underside.
[0019] In another preferred embodiment, the drive as disclosed, further comprising wherein the base plate, on its upper side, has an elevation that is opposite the recess on the underside of the base plate.
[0020] In another preferred embodiment, the drive as disclosed, further comprising wherein the base plate and the U-strap are tightly connected to each other, especially welded, bonded, toxed or clinched.
[0021] In another preferred embodiment, the drive as disclosed, further comprising wherein the base plate and/or the transverse strap consist of metal, especially steel, sheet steel, metal casting or the like.
[0022] In another preferred embodiment, the drive as disclosed, further comprising wherein the base plate has at least one hole, and such holes, if a plurality, are arranged next to each other seen in the axial direction of the spindle.
[0023] In another preferred embodiment, the drive as disclosed, further comprising wherein the base plate has a rectangular outer contour.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a line drawing evidencing the drive already explained according to the known state of the art with a spindle fixed at its end by mountings on which a transmission that can move longitudinally rests.
[0025] FIG. 2 is a line drawing evidencing the part of a spindle similar to FIG. 1 , but with a mounting fastened at one end of the spindle that is designed according to an exemplary embodiment of the invention.
[0026] Each of FIGS. 3 , 4 and 5 is a line drawing evidencing a different view of the mounting shown in FIG. 2 .
DETAILED DESCRIPTION OF THE INVENTION
[0027] The invention essentially consists in that part of the mounting is a base plate, from which two walls at a distance from each other extend upward and at least one of the ends of the spindle is fastened between these two walls, and preferably welded tightly.
[0028] In a preferred exemplary embodiment of the invention, the walls are aligned concentrically to the spindle axis and are about half the length of the base plate.
[0029] An especially simple embodiment of the mounting according to the invention consists of a design variant, in which the two walls of the mounting are the two longitudinal legs of a U-strap, which run in two slots at a distance from each other that and are at least approximately concentrically to the spindle axis and that these slots are machined into the base plate. In this case, the U-strap is slid from below the base plates with its two longitudinal legs through the base plate in such a way that a transverse clip of the U-strap that connects the two longitudinal legs on their underside is in contact with the underside of the base plate.
[0030] A further development of the invention provides that the base plate has a recess on its underside, in which the transverse leg of the U-strap engages. Because of this, the underside of the entire mounting can have an at least approximately flat underside, so the mounting can rest firmly on a base without tipping.
[0031] Another further development of the invention provides that the base plate has an elevation on its upper side exactly at the point where the recess discussed above is located.
[0032] In this embodiment, the base plate is pressed from its underside with a suitable stamp so the recess is formed on the underside and a corresponding elevation occurs on the upper side of the base plate.
[0033] Another embodiment of the invention provides that the base plate and the U-strap are tightly connected to each other, especially welded, bonded, peened or toxed. Toxing (also called clinching) is understood to mean a joining process for connecting sheet metal and profiles. In this process non-detachable connections are produced using local cold forming without additional and/or fastening parts. The main characteristic of this joining technique consists in that the form-fitting connection is formed from the material of the metal sheets and/or parts to be connected. The known work steps in toxing consist of placement of the parts to be joined between stamp and die and subsequent pressing of the materials to be connected into the die by the stamp. If there is further force build-up, the stamp-side material flows into the die form. As a result, a spot-shaped connection is made without edges or burs. A special advantage of toxing is seen in that outstanding corrosion resistance is maintained for galvanized and painted metal sheets and/or parts, since the protective layer is also included.
[0034] The peening connecting technique that is also possible is a similar process, but its difference from toxing consists in that instead of a spot-shaped connection, a longish, crease-like connection of the metal sheets and/or parts occurs with few sharp edges.
[0035] A further development of the invention provides that the base plate and/or the U-strap consists of metal, especially steel or sheet steel or metal castings. In this case, the base plate and the U-strap can be formed from the same material or from different material.
[0036] For fastening a mounting that is designed in this way for holding one end of the spindle, at least one hole, and preferably two holes, are machined into the base plate. If there are two holes, seen along the spindle axis, the holes lie next to each other in longitudinal direction with respect to the spindle axis.
[0037] Advantageously, the base plate has a rectangular outer contour.
[0038] The significant advantage of such a mounting, which is designed in two parts according to the further development named above, namely with a base plate with slot and a U-strap installed in the slot, consists in that such a mounting is optimized for construction space and also ensures an additional increase in strength for a seat longitudinal adjusting drive. This higher strength occurs with a simultaneous greater stiffness of the mounting and a lower forward displacement. The mounting according to the invention requires only a small installation space, is distinguished by higher strength and can replace previously used mountings without problems. Because of the use of a U-strap, a flexible interface design is ensured with respect to standardization of the adjusting drives. Because of the spacing of the two walls extending from the base plate, various spindle diameters can be considered. Overall, the mounting according to the invention is distinguished by a reduction in manufacturing steps and thus by lower costs.
Detailed Description of the Figures
[0039] Referring now to the figures, in FIG. 2 , similarly to FIG. 1 , a spindle 5 is shown, but only in the area of one of the two ends of spindle 5 . The remaining components, especially the gear 9 that can be driven on the spindle 5 , are left out in FIG. 2 for better clarity.
[0040] In contrast to the illustration in FIG. 1 , the spindle 5 is tightly connected at its end 5 a with a specially designed mounting 60 , which will be described in more detail in connection with FIGS. 3 to 5 .
[0041] The mounting 60 has a rectangular base plate of metal, especially of steel or sheet steel or the like. The base plate is provided with the reference number 80 and has, as can be seen from the top view and the side view in FIG. 3 , two fastener holes 64 a and 64 b , which are arranged next to each other in spindle axial direction of the spindle 5 and, in fact, in the representation in FIG. 3 , in the left area of the base plate 80 two slots 82 a and 82 b are found that are at a distance from each other and also parallel to the spindle axis of spindle 5 . These slots 82 a and 82 b extend over about half, or at least approximately half, of the base plate 80 .
[0042] From the cross section representation in FIG. 3 , it can be seen that on its right part, the base plate 80 has a recess 83 and opposite on its upper side a corresponding elevation 84 . This recess 83 and the corresponding elevation 84 can be created by a suitable stamping tool, in that the base plate 80 is stamped from the bottom in order to create the recess 83 on the underside and the corresponding elevation 84 on the upper side.
[0043] FIG. 4 shows a second part of the mounting 60 , namely a U-shaped strap 90 that has two longitudinal legs 92 a , 92 b lying opposite each other, which on their undersides are connected to a transverse leg 93 . The U-strap preferably consists of metal, especially steel or sheet steel or the like.
[0044] The U-strap 90 is designed in such a way that its longitudinal legs 92 a , 92 b can be inserted through the slots 82 a , 82 b of the base plate 80 shown in FIG. 3 so the transverse leg 93 lies in the recess 83 of the base plate 80 .
[0045] FIG. 5 shows the cross section view of the mountings 60 consisting of the two parts, base plate 80 and U-strap 90 , in assembled state and in cross sectional representation. FIG. 2 shows this mounting 60 in perspective representation, whereby the end 5 a of spindle 5 is inserted between the two longitudinal legs 92 a , 92 b of the U-strap 90 and fastened there is a suitable way. This fastening can occur by welding, for example. As an example, in FIG. 2 the associated weld seam is indicated between spindle 5 and the inside of the longitudinal leg 92 a.
LIST OF REFERENCE NUMBERS
[0046] 1 Retaining plate
[0047] 2 Drive motor
[0048] 3 Upper rail
[0049] 4 Lower rail
[0050] 4 a Fastener hole
[0051] 5 Spindle
[0052] 5 a Spindle end
[0053] 6 Mounting
[0054] 6 a Mounting
[0055] 6 b Mounting
[0056] 6 c Fastening nut
[0057] 6 d Fastening nut
[0058] 8 Mounting
[0059] 8 a Fastener hole
[0060] 9 Transmission
[0061] 11 Mounting link
[0062] 21 Drive shaft
[0063] 22 Drive shaft
[0064] 60 Mounting
[0065] 64 a , 64 b Holes
[0066] 70 Weld seam
[0067] 80 Base plate
[0068] 82 a , 82 b Slots
[0069] 83 Recess
[0070] 84 Elevation
[0071] 90 U-strap
[0072] 92 a , 92 b Longitudinal legs/walls
[0073] 93 Transverse leg
[0074] The references recited herein are incorporated herein in their entirety, particularly as they relate to teaching the level of ordinary skill in this art and for any disclosure necessary for the commoner understanding of the subject matter of the claimed invention. It will be clear to a person of ordinary skill in the art that the above embodiments may be altered or that insubstantial changes may be made without departing from the scope of the invention. Accordingly, the scope of the invention is determined by the scope of the following claims and their equitable Equivalents. | 4y
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This application is a continuation of U.S. application Ser. No. 07/962,497, filed Oct. 16, 1992, abandoned, which is a continuation of U.S. application Ser. No. 07/434,586, filed Nov. 13, 1989, abandoned, which is a continuation of U.S. application Ser. No. 894,010, filed Aug. 7, 1986, abandoned.
FIELD OF THE INVENTION
The present invention relates to fluorochemical emulsions which carry on the droplet surface one member of a specific binding pair. The novel emulsions of this invention are useful as diagnostic supports and as supports for biochemical reactions.
BACKGROUND OF THE INVENTION
Supports for antigen/antibody assays and biochemical reactions are typically latex beads, paper, fixed red blood cells and insoluble polymers such as dextran and polystyrene. In these assays and biochemical reactions at least one member of a specific binding pair (hereinafter a "specific binding species") is immobilized on a support and thereafter subjected to chemical reactions, physical manipulation or both in a manner that ultimately results in its binding (transitory or permanent) of the other member of the specific binding pair to the specific binding species. This coupling of the two members of the specific binding pair is useful to detect qualitatively or quantitatively the presence of one of the species in a sample as in a competitive assay, an immunoassay, a protein binding assay. Similarly, the binding of the two members of the specific binding pair can be used to take advantage of the inherent properties of one of the species, e.g., an enzymatic property.
A persistent problem in designing assays and reaction. Systems is the difficulty in immobilizing the specific binding species on the support so that it will withstand washings and remain on the support under the contemplated chemical conditions. Another problem is denaturing the specific binding species pair, i.e., reversing prematurely the binding of the two species such that the bound member disassociates from the immobilized member or the immobilized member and the bound member disassociate from the support. Reactivity of the support under the contemplated conditions of use, resulting in nonspecific binding of constituents in a test sample, is another persistent problem.
Microcapsules have been suggested for use as supports in immune response assays. UK patent Application 2,079,937 A (published 27 Jan. 1982) and UK patent Application 2,079,936 A (published 27 Jan. 1982) both describe making microcapsules with crosslinked wall materials encapsulating an oily core substance. Functional groups with sites for binding an antigen or antibody are attached to the wall by a crosslinking agent.
Fluorocarbon emulsions have been suggested for use as in vivo erythrocyte substitutes. Some fluorocarbon emulsions seem to have good oxygen transport characteristics and appear to be nontoxic and safely metabolized. Other fluorochemical emulsions have been shown to be toxic in laboratory animals or not metabolized and eliminated. Geyer describes various emulsions in Chapter 1, "The Design of Artificial Blood Substitutes", Drug Design, Vol. VII Academic Press, N.Y. (1976) and in "Whole Animal Perfusion with Fluorocarbon Dispensors" Federation Proceedings, Vol. 29 No. 5, p. 1758, (1970). Serum albumin, phospholipids (including lecithin), and surfactants such as Pluronic-F68 (Wyandotte Chemical Corp., Wyandotte, Mich.) have been used as emulsifying agents.
For use as artificial blood Sloviter in U.S. Pat. No. 4,423,007, has suggested emulsions of perfluoro compounds coated with a non-antigenic lipid, preferably egg yolk phospholipid or lecithin, in aqueous medium. He reports In U.S. Pat. No. 4,397,870 that the duration of effective droplet levels in the bloodstream is brief owing to the apparent removal of the lecithin coating and exposure of the perfluoro droplet surface in the bloodstream. Infusion of the patient who has previously received an infusion of an emulsion of coated droplets with the same substance used to coat the perfluoro compound droplet is recommended.
Sloviter in "Erythrocyte Substitute for Perfusion of Brain" Nature Vol. 216, Nov. 1967, 458, has also suggested dispersing a perfluoro compound in a simulated blood plasma compound of 8% bovine serum albumin in Krebs Ringer bicarbonate buffer. After the emulsion was formed and sedimented all soluble protein was washed away. The sedimented material was analyzed and found to contain about 5% protein.
The Japanese have also been active in the field of artificial blood. U.S. Pat. No. 4,252,827 is directed to fluorocarbon compound emulsions that are sufficiently stable to be kept for a long period of time without change in droplet size and can be mixed with plasma extenders such as dextran and hydroxyethyl starch. It describes an emulsion in an organic medium having a perfluorocarbon compound with 9 to 11 carbon atoms, a perfluoro-tert-amine having 9 to 11 carbon atoms, a surfactant having a molecular weight of about 2,000 to 20,000, a phospholipid and at least one fatty acid.
The effect of perfluoro organic compound emulsions on serum proteins and phosolipids has been studied by V. V. Obraztsuv et al. "Binding of Proteins and Phospholipid by Emulsion of Perfluoro Organic Compounds" Ftoruglerodrye Gazoperrnosyaschchie Sridy [531 FA5] 1984 147-52 (Russ). The protocol followed by these authors is not clear. They appear to have analyzed the amount of protein and phospholipids removed from solution only at equilibrium conditions. They do not report any experiments attempting to wash adsorbed protein and phospholipid off the emulsion droplets. They state "irreversible and denaturant character of binding of proteins by the hydrophobic surface raises the question to what extent the concentration of the proteins in the blood might be decreased as a result of the extensive blood substitution with PF0C emulsion."
SUMMARY OF THE INVENTION
The present invention is a stable emulsion having an aqueous continuous phase and a fluorochemical droplet discontinuous phase. At least one specific binding species is immobilized at the surface of the fluorochemical droplets without loss of specific binding capability. As used herein the term "specific binding species" refers to one member of a specific binding pair. The emulsions of the present invention are easily prepared and surprisingly stable over long periods of time. The emulsions withstand washings without loss of specific binding capability.
The relative inertness of fluorochemical to biological molecules as compared to conventional supports makes them ideally suited for use in a wide variety of circumstances. Representative examples of specific binding species which can be immobilized on fluorochemical droplets include one member of an antigen/antibody pairs where the antigen is a naturally occurring or synthetic protein, peptide, polysaccharide, lipid, nucleic acid, organic polymer, an antigenic fragment of these materials, an infectious agent such as bacteria or virus or a portion of their cell surface, a hapten such as a drug, hormone, or organic molecule and combinations and derivatives thereof; a molecule or segment of naturally occuring or synthetic DNA or RNA; an enzyme such as alkaline phosphatase, peroxidase, or beta-galactosidase, luciferass, urease, or other enzymes selected from oxidoreductases, transfereases, hydrolyases, kinases or lyases; another reaction catalyst; a lectin; a sugar; a cell surface marker or receptor; and a therapeutic substance such as a drug, plant extract, hormone or metabolites of these; the other member of the specific binding pair for each of the foregoing; and other components of specific binding reaction schemes such as dyes, fluorescent molecules, or components which in specific binding reaction schemes can be used to produce color, fluorescence, phosphorescence, chemiluminescence or other detectable products.
Another aspect of the invention involves immobilization of combinations of different specific binding species on tile same emulsion droplets. Emulsions having a combination of specific binding species and other components of their specific binding reaction scheme are particularly useful in diagnostic systems. Thus one member of an antigen/antibody binding pair and a material which is or reacts to form a detectable product such as an enzyme, dye, fluoroescent molecule, or chemiluminescent reagent can be independently immobilized on emulsion droplets. Immobilization of multiple specific binding species allows the immobilization of the separate components of an enzyme cascade which can be used to determine the presence and amount of a substance. For example glucose can be detected with the enzymes glucose oxidase and peroxidase linked to the same emulsion droplet.
The specific binding species may be immobilized on the fluorochemical droplet by direct adsorption at the droplet/aqueous interface. Alternatively a primer material may be used. A "primer material" is a material which has the ability to couple a specific binding species to a fluorochemical droplet. Naturally occurring or synthetic polymers with amine, carboxyl, mercapto, or other functional groups capable of specific reaction with coupling agents and highly charged polymers are preferred. The specific binding species may be immobilized by covalently bonding it to a primer material and adsorbing the conjugate at the interface of the discontinuous and the continuous phases. Alternatively the specific binding species may be adsorbed to a primer material and the resulting complex adsorbed at the interface of the continuous and discontinuous phases. The same result can be achieved by forming an emulsion with an aqueous continuous phase and a fluorochemical discontinuous phase using a primer material as an emulsifying agent. Then the biologically active moiety may be adsorbed or conjugated to the primer material at the interface of the continuous and discontinuous phases.
Yet another aspect of the invention involves incorporating a "dye" into the fluorochemical droplet. "Dyes" as used herein are species which can be detected by spectrophotometric, fluorometric or colorimetric means.
The process of the present invention involves providing an in vitro emulsion having an aqueous continuous phase and a fluorochemical discontinuous phase. At least one specific binding species is immobilized on the fluorochemical droplets. The fluorochemical droplets and immobilized specific binding species are contacted with an aqueous solution containing the specific binding partner of the specific binding species for a period of time sufficient to permit binding of the specific binding species to its partner. The process is preferably used in diagnostic procedures such as agglutination assays, sandwich or reverse inhibition enzyme immunoassays or radio immunoassays, or a protein binding assay.
DETAILED DESCRIPTION
The emulsions of the present invention may be made with a large variety of materials.
A variety of fluorochemical liquids may be used. Suitable fluorochemical liquids include straight and branched chain and cyclic perfluorocarbons, straight and branched chain and cyclic perfluoro tertiary amines, straight and branched chain and cyclic perfluoro ethers and thioethers, chlorofluorocarbons and polymeric perfluoro ethers and the like. Although up to 50% hydrogen-substituted compounds can be used, perhalo compounds are preferred. Most preferred are perfluorinated compounds. Exemplary fluorochemicals useful in the present invention are commercially available materials such as the fluorochemicals sold with the trademarks Kel-F® and Fluorinerts® (3M, St. Paul, Minn.), Freon® and Series E (DUpont, Wilmington, Del.) and Fomblins® (Montedison, Italy).
Although any fluorochemical liquid i.e. a substance which is a liquid at about 20°C. at atmospheric pressure, can be used to prepare a fluorochemical emulsion of the present invention, for many purposes emulsions with longer extended stability are preferred. In order to obtain such emulsions, fluorochemical liquids with boiling points above 30° C are preferred. Preferably the fluorochemical liquids have boiling points above 50°C., and most preferred are fluorochemical liquids with boiling points above about 100° C.
Suitable fluorochemical liquids include perfluorodecalin, perfluoro-n-pentane, perfluoromorpholine, perfluorotriamylamine, perfluorodimethylcyclohexane, perfluorodicyclohexyl ether, perfluoro-n-butyltetrahydrofuran, perfluoro-n-octyl bromide, perfluorotri-n-butylamine, and compounds which are structurally similar to these compounds and are partially or fully halogenated (including at least some fluorine substituents) or partially or fully perfluorinated.
Emulsifying agents, for example surfactants, may be used to facilitate the formation of emulsions. Typically, aqueous phase surfactants have been used to facilitate the formation of emulsions of fluorochemical liquids. One of the primer materials such as albumiris, polysaccharides, and phospholipids may be used as an emulsifying agent. Other known surfactants such as Pluronic F-68, a block copolymer of --O(CH 2 ) 2 --O--(CH 2 ) 2 --O-- and --O--(CH 2 ) 3 --O--(CH 2 ) 3 --O--, may be used.
Some examples of suitable surfactants are
anionics, such as those sold with the trade names:
Hamposyl™ L30 (W.R. Grace Co., Nashua, N.H.), Sodium dodecyl sulfate,
Aerosol 413 (American Cyanamid Co., Wayne, N.J.),
Aerosol 200 (American Cyanamid Co.),
Lipoproteol™ LCO (Rhodia Inc., Mammoth, N.J.),
Standapol™ SH 135 (Henkel Corp., Teaneck, N.J.),
Fizul™ 10-127 (Finetex Inc., Elmwood Park, N.J.), and
Cyclopol™ SBFA 30 (Cyclo Chemicals Corp., Miami, Fla.);
amphoterics, such as those sold with the trade names:
Deriphat™ 170 (Henkel Corp.),
Lonzaine™ JS (Lonza, Inc.),
Niranol™ C2N-SF (Miranol Chemical Co., Inc., Dayton, N.J.),
Amphoterge™ W2 (Lonza, Inc.), and
Amphoterge™ 2WAS (Lonza, Inc.);
non-ionics, such as those sold with the trade names:
Pluronic™ F-68 (BASF Wyandotte, Wyandotte, Mich.),
Pluronic™ F-127 (BASF Wyandotte),
Brij™ 35 (ICI Americas; Wilmington, Del.),
Triton™ X-100 (Rohm and Haas Co., Philadelphia, Pa.),
Brij™ 52 (ICI Americas),
Span™ 20 (ICI Americas),
Generol™ 122 ES (Henkel Corp.),
Triton™ N-42 (Rohm and Haas Co.,),
Triton™ N-101 (Rohm and Haas Co.,),
Triton™ X-405 (Rohm and tlaas Co.,),
Tween™ 80 (ICI Americas),
Tween™ 85 (ICI Americas), and
Brij™ 56 (ICI Americas).
These surfactants' are used alone or in combination in amounts of 0.10 to 5.0% by weight to assist in stabilizing the emulsions.
Fluorinated surfactants which are soluble in the fluorochemical liquid to be emulsified can also be used. Suitable fluorochemical surfactants include perfluorinated alkanoic acids such as perfluorohexanoic and perfluorooctanoic acids and amidoamine derivatives thereof such as C 7 F 15 CONH(CH 2 ) 4 N(CH 3 ) 2 and 1,1-dihydroperfluoroalcohols such as 1,1-dihydroperfluoro-n-octanol. These surfactants are generally used in amounts of 0.01 to 5.0% by weight, and preferably in amounts of 0.1 to 1.0%.
Other suitable fluorochemical surfactants include perfluorinated alcohol phosphate esters and their salts; perfluorinated sulfonamide alcohol phosphate esters and their salts; perfluorinated alkyl sulfonamide alkylene quaternary ammonium salts; N,N-(carboxyl-substituted lower alkyl) perfluorinated alkyl sulfonamides; and mixtures thereof. As used herein, the term "perfluorinated" means that the surfactant contains at least one perfluorinated alkyl group.
Suitable perfluorinated alcohol phosphate esters include the free acids of the diethanolamine salts of mono- and bis(1H,1H,2H,2H-perfluoroalkyl)phosphates. The phosphate salts, available under the tradename "Zonyl RP" (E.I. Dupont de Nemours and Co., Wilmington, Del.), are converted to the corresponding free acids by known methods. Suitable perfluorinated sulfonamide alcohol phosphate esters are described in U.S. Pat. No. 3,094,547, and have the general formula: ##STR1## wherein R is hydrogen or an alkyl group having 1 to about 12 carbon atoms, preferably from 1 to 6 carbon atoms; R' is an alkylene bridging group containing 2 to 12 carbon atoms, preferably from 2 to 8 carbon atoms; R f is perfluoroaliphatic C n F 2n+1 or perfluorocycloaliphatic C n F 2n-1 (n is an integer from 1 to 18, preferably from 6 to 12); and m is an integer from 1 to 3. Although each of the mono-, di- and triesters are useful, the diester is most readily available commercially. Suitable perfluorinated sulfonamide alcohol phosphate esters and salts of these include perfluoro-n-octyl-N-ethylsulfonamidoethyl phosphate, bis(perfluoro-n-octyl-N-ethylsulfonamidoethyl) phosphate, the ammonium salt of bis(perfluoro-n-octyl-N-ethylsulfonamidoethyl)phosphate, bis(perfluorodecyl-N-ethylsulfonamidoethyl)phosphate and bis(perfluorohexyl-N-ethylsulfonamidoethyl)phosphate.
The preferred formulations use Pluronic F-68 as the aqueous surfactant in phosphate buffered saline and perfluoroamidoamines and perfluorodihydroalcohols as the fluorochemical surfactants.
The fluorochemical emulsion can be prepared with or without a primer material. Suitable primer materials include proteins such as albumins (e.g. bovine serum albumin and ovalbumin), casein, whole sera such as normal human serum, fibrinogen, collagens, synthetic poly(amino acids) e.g. poly(lysine-phenylalanine) and polylysine. Primer materials rich in lysine content produce emulsions droplets which are highly active in coupling reactions. Use of copolymers which have a one to one ratio of lysine with a hydrophobic amino acid such as alanins or phenylalanine as primer materials results in a very high concentration of amino groups available for coupling reactions. These lysine-hydrophobic amino acid copolymers are adsorbed tightly with the hydrophobic residues interacting with the fluorochemical fluid phase. In some cases, however, the use of the copolymer alone as a primer material may result in crosslinking of emulsion droplets during coupling reactions with specific binding species. A mixture of bovine serum albumin and copolymer alleviates the crosslinking problem, however the amount of specific binding species that, can be coupled is also reduced. Other suitable primer materials include naturally occurring or synthetic polymers which are highly charged such as charged polysaccharides e.g. heparin, dextran sulfate, DIMA (a dimethylamine adduct of expoxidized polybutadiene as disclosed, in U.S. Pat. No. 4,210,722), protamine sulfate, nucleic acids and the like.
The emulsions of the present invention may be prepared by various techniques. One method is sonication of a mixture of a fluorochemical liquid and an aqueous solution containing a suitable primer material or specific binding species. Generally, these mixtures include a surfactant. Cooling the mixture being emulsified, minimizing the concentration of surfactant, and buffering with a saline buffer will maximize both retention of specific binding properties and the coupling capacity of the primer material. These techniques provide excellent emulsions with high activity per unit of absorbed primer material or specific binding species.
When high concentrations of a primer material or specific binding species coated on fluorochemical droplets are desired, the mixture should be heated during sonication, the mixture should have a relatively low ionic strength, and the aqueous solution should have a moderate to low pH. Too low an ionic strength, too low a pH and too much heat in some cases may cause some degradation or loss of all of the specific binding properties of the specific binding species or the coupling capacity of the primer material. Careful control and variation of the emulsification conditions will optimize the properties of the primer material or the specific binding species while obtaining high concentrations of coating. Variation of ionic strength, pH, and temperature have been found to be particularly valuable where bovine serum albumin is the primer material.
The quality of the emulsions obtained can be evaluated by conventional techniques such as visual observation, nephelometry, coulter counter measurement or spectrophotometric measurement. When suitable indicators are included in the emulsion components, such as dyes or fluorescent and chemiluminescent markers, the emulsion droplets can be observed by the properties of these materials. The useful emulsions may have a wide range of mean droplet diameters, e.g., from as small as 0.01 microns to as large as 500 microns. The droplet sizes can be controlled and varied by modifications of the emulsification techniques and the chemical components.
While preparation of emulsions by sonication has been acceptable, some degree of variability of droplet size distribution of the droplets is observed. An alternative method of making the emulsions involves directing high pressure streams of mixtures containing the aqueous solution, a primer material or the specific binding species, the fluorocarbon liquid and a surfactant (if any) so that they impact one another to produce emulsions of narrow droplet size distribution and small droplet size. The Microfluidizer™ apparatus (Microfluidics, Newton, Mass.) is used to make the preferred emulsions. The apparatus is also useful to process emulsions made by sonication or other conventional methods. Feeding a stream of droplets through the Microfluidizer™ apparatus yields emulsions having narrow droplet size distribution and small droplet size.
The specific binding species may be immobilized on the fluorochemical droplet surface by direct adsorption or by chemical coupling. Examples of specific binding species which can be immobilized by direct adsorption include antibodies, protein A, and enzymes. To make such an emulsion the specific binding species may be suspended or dissolved in the aqueous phase prior to formation of the emulsion. Alternatively, the specific binding species may be added after formation of the emulsion and incubated with agitation at room temperature (25° C.) in a pH 7.0 buffer (typically phosphate buffered saline) for 1.2 to 18 hours.
Where the specific binding species is to be coupled to a primer material, conventional coupling techniques may be used. The specific binding species may be covalently bonded to primer material with coupling agents using methods which are known in the art. One type of coupling agent uses a carbodiimide such as 1-ethyl-3-(3-N,N-dimethylaminopropyl)carbodiimide hydrochloride or 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide methyl-p-toluenesulfonate. Other suitable coupling agents include aidehyde coupling agents having either ethylenic unsaturation such as acrolein, methacrolein, or 2-butenal, or having a plurality of aidehyde groups such as glutaraldehyde, propanedial or butanedial. Other coupling agents include 2-iminothiolane hydrochloride, bifunctional N-hydroxysuccinimide esters such as disuccinimidyl subsrate, disuccinimidyl tartrate, bis[2-(succinimidooxycarbonyloxy)ethyl]sulfone, disuccinimidyl propionate, ethylene glycolbis(succinimidyl succinate); heterobifunctional reagents such as N-(5-azido-2-nitrobenzoyloxy)succinimide, p-azidophenylbromide, p-azidophenylglyoxal, 4-fluoro-3-nitrophenylazide, N-hydroxysuccinimidyl-4-azidobenzoate, m-maleimidobenzoyl N-hydroxysuccinimide ester, methyl-4-azidophenylglyoxal, 4-fluoro-3-nitrophenyl azide, N-hydroxysuccinimidyl-4-azidobenzoate hydrochloride, p-nitrophenyl 2-diazo-3,3,3-trifluoropropionate, N-succinimidyl-6-(4'-azido-2'-nitrophenylamino)hexanoate, succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate, succinimidyl 4-(p-maleimidophenyl)butyrate, N-succinimidyl(4-azidophenyldithio)propionate, N-succinimidyl 3-(2-pyridyldithio)propionate, N-(4-azidophenylthio)phthalamide; homobifunctional reagents such as 1,5-difluoro-2,4-dinitrobenzene, 4,4'-difluoro-3,3'-dinitrodiphenylsulfone, 4,4'-diisothiocyano-2,2'-disulfonic acid stilbene, p-phenylenediisothiocyanate, carbonylbis(L-methionine p-nitrophenyl ester), 4,4'-dithiobisphenylazide, erythritolbiscarbonate and bifunctional imidoesters such as dimethyl adipimidate hydrochloride, dimethyl suberimidate, and dimethyl 3,3'-dithiobispropionimidate hydrochloride. Covalent bonding of a specific binding species to the primer material can be carried out with the above reagents by conventional, well-known reactions, for example, in the aqueous solutions at a neutral pH, at temperatures of less than 25° C. for 1 hour to overnight.
In some applications the emulsions of the present invention are more useful if the fluorochemtcal droplets incorporate dye which can be detected by spectrophotometric, fluorometric, or colorimetric means. For example, agglutination end points are more easily observed with the naked eye when the fluorochemical droplet is colored. Suitable dyes useful for this purpose are dyes sufficiently soluble in fluorinated liquids to color the liquid. The preferred dyes are soluble in perfluorinated liquids. Such dyes will typically possess one or more solubilizing groups such as halogenated side chains or preferably a perfluorinated side chain such as a perfluoroalkyl or perfluoroalkyl ether side chain or perfluorinated cyclic group. Some examples of suitable dyes are the perfluoroalkylated phthalein, phthalocyanine, rhodamine, and quinophthaline dyes described in U.S. Pat. No. 3,281,426 which is hereby incorporated by reference. Representative dyes described in that patent are thioindigo (pink), pyranthrone (orange), violanthrone (dark blue), isoviolanthrone (violet), and Tiers' Blue, a copper phthalocyanine substituted by perfluoroalkyl groups: ##STR2## A substituted methyl red analog with a perfluoroalkyl group is: ##STR3## Other suitable dyes are perfluoroalkyl-beta-diketone lanthanide complexes such as, ##STR4## wherein R f and R 1 f are perfluoroalkyl or perfluoroaryl and the like.
The soluble dyes may be dissolved in the fluorochemical liquid to be emulsified before emulsification by simple mixing, optionally with heating. Alternatively, the addition of the soluble dye and the emulsification may be carried out simultaneously using standard emulsification techniques such as sonication and mechanical emulsification as obtained using a motorized french press, Model FA-078 (available from SLM Instruments, Inc., Urbana, Ill.). Dye can be added to the emulsions after the formation of the emulsions, although this operation may be more difficult because the primer material or the specific binding species may act as a barrier.
Combinations of different dyes in separate droplets offer the possibility of preparing emulsions of any color. Selective removal of one color of droplets due to an antibody-antigen aggregation reaction for example, would cause a change in the apparent color of the emulsion. Also dyed droplets which are adhered to a dipstick, due to an antigen-antibody reaction, would produce a color on a dipstick. Both of these approaches have the potential of producing an easily interpreted, qualitative endpoint for a number of immunoassays.
Dye precursors may also be used. For instance, color forming agents may be associated with the surface of droplets so that they can couple to an appropriate material to form dyes (a type of color coupling technique). This could be accomplished using the diazo salt used to produce the perfluoroalkyl methyl red material described above.
Further aspects of the invention, including the process of using the emulsions, will be apparent from the following non-limiting examples.
EXAMPLE 1
In order to compare the formation of fluorochemicals emulsions in a standard way, each of fluorochemicals fluids shown in Table 1 was emulsified by sonication in an ice bath cooled rosette cell for five minutes. Each fluorochemical liquid (100 microliters) was dispersed at a concentration of 1 volume % in 10 ml of aqueous saline, phosphate buffered to pH 7 and containing 0.5% by weight Plutonit F-68 as a surfactant.
These solutions were evaluated after one day and again after 7 days for droplet size by recording the amount of sedimentation. Droplet size was determined on a qualitative basis under 400×magnification with dark field illumination after 1 and 7 days.
The low boiling perfluorocarbons FC-78 and FC-88 and the chlorofluorocarbons Freon 113 and Kel-F1 formed poorer quality emulsions than the rest of the substances. The presence of nitrogen or oxygen in the fluorinated compounds appeared to result in increased emulsion stability and decreased droplet size in this group of substances.
TABLE 1______________________________________PERFLUORINATED LIQUID______________________________________ 1. Decalin (PP-5: DuPont) 2. n-Pentane (FC-88: 3M) 3. Morpholine (FC-78: 3M) 4. Tri-n-amylamine (FC-70: 3M) 5. Dimethylcyclohexane (FC-82: 3M) 6. Polyether E-2 (DuPont) 7. Polyether E-5 (DuPont) 8. Kel F-1 (3M) (Cl(CF.sub.2CClF).sub.2 Cl) 9. Fomblin LS (Montedison) ##STR5##10. Freon 113 (DuPont) (Cl.sub.3 CCF.sub.3)11. Dicyclohexyl ether (DCE)12. Octyl Bromide (OB)13. Tri-n-butylamine (FC-43: 3M)14. C-8 Cyclic ether (FC-75: 3M)15. C-8 Mixture (FC-77: 3M)______________________________________
EXAMPLE 2
A fluorochemical cosurfactant consisting of perfluoro-n-octanoic acid or perfluoroamidoamine, C 7 F 15 C(O)NH(CH 2 ) 4 N(CH 3 ) 2 was dissolved in each of the fluorochemical fluids of Table I before the emulsion was prepared as in Example 1. The perfluoroacid-containing fluorochemicals were emulsified in the surfactant buffer described in Example 1 with 0.05 to 0.1% bovine serum albumin (BSA) solution and the perfluoroamidoamine-containing fluorochemicals were emulsified in a 0.05% DIMA solution. These emulsions were also evaluated for droplet size and sedimentation as described in Example 1. Each of the fluorochemicals listed in Table 1 was successfully dispersed as an emulsion with these fluorocarbon and polymer cosurfactants. These emulsions appeared to be more stable and their droplet size was generally smaller than the emulsions prepared without the cosurfactants in Example 1.
EXAMPLE 3
The emulsions prepared in Example 2 were analyzed for the amount of fluorochemical dispersed, the amount of BSA or DIMA bound to the surface of the droplets, and the sizes of the droplets produced. Prior to this analysis the emulsions were separated from free protein by addition of a saturated solution of ammonium sulfate, volume:volume, centrifugation of the precipitate and resuspension of the precipitate in fresh buffer-surfactant solution. This was followed by centrifugation at 30,000×g for 15 minutes and resuspension in fresh buffer-surfactant solution two additional times.
The fluorochemical content of these emulsions was determined by 9as chromatographlc analysts on an OV-101 packed column, 6 feet×0.125 inch. The fluorochemical content was determined by comparison with a standard curve prepared by injection of known amounts of FC-43. Since the response of the flame ionization detector (FID) varied somewhat to the various fluorochemicals emulsified, the fluorochemical content calculated also varied accordingly.
The amount of BSA and DIMA on the surface of the emulsion droplets was determined by the Bradford method using Coomassie Blue G-250 and a standard curve prepared with known amounts of BSA and DIMA.
The size of emulsion droplets was examined by microscopic evaluation (400×under dark field illumination) and assigned a numerical score on days one and seven after preparation. A numerical score was determined by assigning a value of 1, 2, 3, 4, 5, or 6 to emulsion droplets judged to be about the size of 200, 330, 460, 800, 1200, or above 2500 nanometers, respectively, by comparison to sized polystyrene latex beads (Sigma Chemical). Using a representative microscopic field of each sample, the number of droplets of a particular size range were multiplied by their size value.. The final score for an emulsion was the sum of these size scores divided by the total number of droplets. When an emulsion sample appeared to have a substantial number of droplets aggregated into clumps, the emulsions were noted as aggregated and were not scored further.
The analytical results and scores assigned by microscopic examination of these emulsions are shown in Table 2. This data shows that significant amounts of BSA or DIMA are present on the droplet surface after emulsification and that it is not removed by repeated washing with fresh buffer-surfactant. The amount of BSA or DIMA found bound to the fluorochemical (milligrams per milliliter of fluorochemical emulsion) is greatest in dispersions of FC-43, FC-75, E-2, E-5, and DCE, which are fluorochemicals with heteroatoms (nitrogen or oxygen). Also, more BSA is bound than is DIMA for all formulations.
The size data indicates emulsions formulated with BSA showed a tendency to aggregate into clumps of droplets while the DIMA emulsions did not. Additionally, the change in numerical score of some of the emulsions over the 7 day period indicates that these preparations are dynamically approaching a more stable size distribution for the particular formulation.
TABLE 2__________________________________________________________________________Fluorocarbon Emulsions Prepared for Quantitative Comparison Fluoro- Micro Protein carbonFluoro- Exam Content ContentcarbonEmulsifier 1 day 7 day mg %__________________________________________________________________________PP-5 BSA-Acid 1.58 1.58 7.53 2.97DIMA-Amidoamine 1.58 1.67 5.93 2.74FC-70BSA-Acid 1.88 Agg 9.95 0.71DIMA-Amidoamine 1.88 1.59 4.74 0.68FC-82BSA-Acid 1.54 1.43 9.86 1.07DIMA-Amidoamine 1.54 1.59 4.74 0.96E-2 BSA-Acid 1.65 1.82 19.0 0.53DIMA-Amidoamine 1.65 1.50 8.85 0.67E-5 BSA-Acid 2.06 Agg 13.1 0.48DIMA-Amidoamine 2.06 2.19 5.73 0.52LS BSA-Acid 1.65 Agg 10.8 0.51DIMA-Amidoamine 1.65 2.10 4.71 0.52DCE BSA-Acid Agg Agg 14.0 0.66DIMA-Amidoamine 1.60 2.10 7.44 0.65OB BSA-Acid 1.60 2.03 10.1 0.54DIMA-Amidoamine 1.60 2.59 2.66 0.25FC-43BSA-Acid Agg Agg 11.3 0.59DIMA-Amidoamine 2.03 2.54 6.04 0.62FC-75BSA-Acid 1.54 1.80 12.5 1.04DIMA-Amidoamine 1.80 1.54 7.28 0.71FC-77BSA-Acid 2.06 1.54 12.1 0.86DIMA-Amidoamine 2.06 1.52 9.83 0.71__________________________________________________________________________ Agg = Aggregated droplets.
EXAMPLE 4
Emulsions were prepared with a variety of aqueous surfactants by sonication of mixtures containing 1 volume % of FC-43 containing 0.5 weight % of either perfluoroctanoic acid or perfluoroamidoamine, as in example 2, and phosphate buffered saline containing a 0.5 weight % of Emerst 2400, Triton X-100, Tween 40, Pluronic P-85, Pluronic F-38 (nonionic surfactants), lauric acid, Triton X-200, Emersol 6434 (anionic surfactants), Miranol C 2 M-SF (an amphoteric surfactant), or C 10 F 21 S(O) 2 NH--(CH 2 ) 3 --N(CH 3 ) 3 Cl (a cationic fluorochemical surfactant) at pH 6.5 to 8.5. Before sonication BSA (0.5% final concentration) was added to perfluoroacid mixtures and DIMA (0.5% final concentration) was added to perfluorooamidoamine mixtures.
The emulsions were evaluated at days 1, 4, and 7 after preparation with regard to sedimentation and emulsion droplet size as noted in Examples 1, 2, and 3 above. Those prepared with nonionic and amphoteric aqueous surfactants were superior to those prepared with anionic or cationic surfactants.
EXAMPLE 5
Emulsions were prepared with 10 volume % FC-43 containing 0.5 to 1.0 weight % C 7 F 15 CO 2 H in phosphate buffered saline at pH 7 with either 0.05 weight % Tween 20 or 0.1 weight % C 7 F 15 CO 2 H as a surfactant. The resultant emulsions were washed using the centrifugation and resuspension procedure described in Example 3. To a 0.5 milliliter aliquot of these emulsions alkaline phosphatase (Sigma type VIIT) or Protein A (Sigma Chemical Company) were added and incubated for 0.5 to 18 hours. The emulsions were then again washed by the procedure above before being assayed for alkaline phosphatase activity with a chromogenic substrate, p-nitrophenylphosphate, or for protein A activity by agglutination with immunoglublin G (IgG). These assays were positive for the respective specific binding species demonstrating that such materials can be adsorbed to the emulsion droplet and maintain their activity.
EXAMPLE 6
Emulsions were prepared as in Example 4 with the addition of 0.5 weight % of a perfluoroether polymer with terminal ester functional groups CH 3 O 2 CCF 2 O--(CF 2 CF 2 O) 7 (CF 2 O) 14 --CF 2 CO 2 CH 3 (the CF 20 and CF 2 CF 2 O units are randomly interspersed) in the FC-43 in place of the perfluoroacid. Alkaline phosphatase was added as in Example 5 and also was found to adsorb to the emulsion droplets.
EXAMPLE 7
Emulsions were prepared with 1 to 5 volume % of FC-43 containing 0.1 to 0.5 weight % each of C 7 F 15 C(O)NH--(CH 2 ) 4 --N(CH 3 ) 3 and C 7 F 15 CH 2 OH in solutions of a series of proteins, synthetic polyamino acids, and polysaccharides as listed in Table 3. The emulsions were prepared by sonication of the FC-43 mixture, addition of an equal volume of phosphate-buffered saline containing 2% by weight Pluronic F-68 at pH 7 and thrice washed by centrifugation at 30,000 g for 15 minutes and by resuspension in fresh surfactant-buffer solution containing no BSA.
The resulting emulsions were coupled to alkaline phosphatase (Sigma Type VIIT) using either Method A, C, E or F, listed below. With each material alkaline phosphatase activity was recovered on the emulsion droplets demonstrating both that the material was adsorbed to the droplet surface and that it was available for immobilization of enzyme antibodies or antigens. The materials thus prepared are suitable for one to detect the presence, concentration, or both of an antigen or antibody in a sample. Emulsions prepared with fibrinogen and ovalbumin tended to aggregate during the processing operations while the other materials produced more acceptable emulsions.
TABLE 3______________________________________MATERIALS USED TO PREPARE FLUOROCHEMICALEMULSION-BIOMOLECULE COMBINATIONSBiomolecule in ConcentrationAqueous Solution (mg/ml) pH______________________________________Bovine Serum Albumin 0.5 to 10 7 or 0Casein 2 to 10 12Gelatin 2 to 10 1Collagen 1.8 to 3.6 3Ovalbumin 2 to 5 1Normal Human Serum 2 to 10 5Fibrinogen 1 11Protamine Sulfate 0.5 to 2.0 4 or 0Poly(lysine) 0.5 to 1.0 4 or 0Poly(phenylalanine-lysine) 0.5 4 or 0Poly(alanine-lysine) 0.5 4 or 0Heparin 1.0 4Dextran Sulfate 1.0 4______________________________________
EXAMPLE 8
An emulsion was prepared as in Example 7 with BSA in the aqueous phase and washed as in Example 7. To an aliquot of this emulsion the antibody, anti-BSA, was added and upon mixing aggregation of the emulsion occurred which was observed by changes (increases) in the optical density of the emulsion. Using this technique the presence of the antibody was detected and measured semi-quantitatively, using standard curves generated on a spectrophotometer. This result verified that BSA was very tightly bound to the emulsion droplet surface and was antigenically active.
EXAMPLE 9
An aliquot of the emulsion prepared and washed in Example 8 was mixed with fluorescein-labeled anti-BSA producing aggregation of emulsion droplets. These clumps were fluorescent as viewed by a fluorescence microscope indicating that the antibody was acting to crosslink and aggregate the emulsion droplets. This result also verified that BSA is very tightly bound to the droplet surface and. was antigenlcally active.
EXAMPLE 10
Emulsions with 1 volume % FC-43 containing 0.1 weight % each C 7 F 15 CH 2 OH and C 7 F 15 C(O)NH--(CH 2 ) 4 N(CH 3 ) 2 or C 7 F 15 C(O)NH--C 6 H 4 N(CH 3 ) 2 were prepared in 0.5 weight % poly(phenylalanine-lysine) solution at pH 0 by sonication for 5 minutes in a rosette cell. After sonication the emulsions were stabilized with an equal volume of phosphate buffered saline containing 2.0 weight % Pluronic F-68 and 0.2 weight % triethanolamine. The dispersions were washed by the procedure of Example 7 before being coupled to specific binding species by one of the methods described below.
Substances which have been coupled to emulsions successfully and the methods which have been used for these reactions are shown in Table 4. The substances were coupled alone or in combinations which resulted in separate specific binding activities being recovered intact on the same emulsion droplets. The materials were obtained from commercial sources as follows: Glucose Oxidase (Sigma Type V), horseradish peroxidase (Sigma Type VI), alkaline phosphatase (Sigma Type VIIT), beta-galactosidase (Sigma Grade VIII), wheat germ agglutinin (Triticum vulgaris lectin, Sigma), PHA (Phaseolus vulgaris lectin, Sigma), Protein A (Sigma), rabbit anti-goat IgG (Cappel Laboratories and American Qualex), mouse anti-hCG (Hybritech, Monoclonal), rabbit anti-HRP (Sigma), Goat IgG (Cappel Laboratories), hCG (Sigma), luminol (Sigma), and DL-thyroxin (Sigma).
The coupled emulsions were evaluated for the material immobilized by known procedures, e.g., enzymes by the assay procedures supplied by the source, antibodies with their antigens in agglutination reactions, lectins by red blood cell agglutination, protein A by binding of IgG's and their reaction with antigen and luminol by reaction with peroxide and peroxidase. When combinations of materials were coupled to emulsions, separate assays for each component were carried out.
TABLE 4______________________________________Materials Coupled to Fluorochemical EmulsionsMaterial Method______________________________________Glucose Oxidase A,C,E,FHorseradish Peroxidase E,F,IAlkaline Phosphatase A,B,C,D,G,HBeta-Galactosidase AWheat Germ Agglutinin APhaseolus vulgaris lectin (PHA) Aanti-Horseradish Peroxidase AGoat Immunoglobulin G (IgG) C,E,Ganti-Goat IgG A,GThyroxin (T-4) DLuminol DHuman Chorionic Gonadotropin (hCG) C,G,Ianti-hCG C,GProtein A A______________________________________
METHOD A
Carbodiimide Method 1
To 2 ml of an emulsion (1 to 2% by volume) at pH 7.0 in phosphate buffered saline containing 2% Pluronic F-68 and 0.2% triethanolamine, 0.05 to 1.0 mg of the substance to be coupled was added in water solution (0.1 to mg per ml) followed by 100 to 500 microliters of a carbodiimide reagent (generally 1-[3-(N,N-dimethylamino)propyl]-3-ethylcarbodiimide at 2 mg/ml in water). The mixture was mixed at room temperature for 1 to 2 hours and 0.5 ml each of 1.0M glycine and 10% ethanolamine were added and mixed for an additional two hours. The coupled emulsion was centrifuged at 12,900 g for 30 minutes. The supernatant was discarded and the emulsion pellet resuspended in fresh surfactant buffer. This centrifugation and resuspension procedure was repeated two more times. The resulting emulsion was then ready for use.
METHOD B
Carbodiimide Method 2
The substance to be coupled to the emulsion was activated with carbodiimide reagent solution (as in Method A) at room temperature for 30 to 60 minutes. The ratio of carboiimide reagent was generally in a two to five-fold molar excess. Dialysis for 2 to 6 hours at room temperature with 3 buffer changes or diafiltration with 10 volumes of filtrate was usually satisfactory to remove excess reagent. This activated solution was then added to 2 ml of emulsion and the mixture rotated for 2 to 6 hours at room temperature. As in Method A glycine and ethanolamine were then added to cap activated groups and the coupled emulsion was isolated as described in Method A.
METHOD C
Glutaraldehyde Method 1
To two ml of an emulsion in saline, phosphate-buffered at pH 7.0 containing 2% Pluronic F-68 and 0.2% triethanolamine, the substance to be coupled to the emulsion, 0.05 to 1.0 mg, was added in aqueous solution (0.1 to 10 mg per ml) along with 100 to 500 microliters of 1% glutaraldehyde monomer solution (Sigma Chemical Co., Grade I). The mixture was then mixed at room temperature for 30 to 60 minutes. The reaction was stopped by adding 500 microliters of 10% ethanolamine and mixed for 2 to 18 hours. Sodium borohydride, 500 microliters of 2 mg/ml in water (freshly prepared), was then added and the mixture; rotated for an additional 30 minutes. Clean-up by centrifugation and resuspension was carried out as specified in Method A.
METHOD D
Glutaraldehyde Method 2
The surface of 2 ml of an emulsion in surfactant buffer was activated by reaction with 250 microliters of 1% glutaraldehyde monomer solution for 30 minutes and then dialyzed against surfactant buffer at 4° C. for 18 hours with 3 changes of buffer. Then an aqueous solution of the material to be coupled to the emulsion was added (0.05 to 1.0 mg) and rotated for 18 hours. The coupling reaction was stopped by addition of 500 microliters of 10% ethanolamine and the emulsion recovered by the procedure described in Method A.
METHOD E
Periodate Method 1
A solution of the substance to be coupled was dissolved in 0.3M sodium bicarbonate at about 5 mg/ml, pH 8.1, and was activated by reaction with one milliliter of 0.6M sodium periodate solution for 5 minutes, followed by the addition of one milliliter of 0.16M ethylene glycol solution for 30 minutes. The reaction mixture was then extensively dialyzed against 0.01M sodium bicarbonate. The activated material, 100 to 200 microliters, was then added to two milliliters of emulsion; 100 microliters of sodium cyanoborohydride (100 mg/ml) was added and the mixture rotated for two hours unreacted activated groups were then capped by reaction with 100 microliters of 10% ethanolamine for 1 hour followed by reaction with 1 mg of sodium borohydride for another 30 minutes. The coupled emulsion was then recovered by the centrifugation and resuspension procedures described in Method A.
METHOD F
Periodate Method 2
To 2 ml of emulsion in surfactant buffer and 0.05 to 1.0 mg of the substance to be coupled, 200 microliters of 0.06M sodium periodate at pH 7 and 100 microliters of sodium cyanoborohydride (100 mg/ml) was added and the mixture was rotated for 1 hour. The excess reagent was reacted with 200 microliters of 0.16M ethylene glycol and 200 microliters of 10% ethanolamine for an hour and the coupled emulsion was purified by the centrifugation and resuspension procedure of Method A.
EXAMPLE G
Bifunctional Acid Method 1
To a mixture of 2 ml of emulsion in surfactant buffer and 0.05 to 1.0 mg of substance to be coupled to the emulsion was added 100 microliters of freshly prepared bis(N-hydroxysuccinimidyl)terephthalate solution (10 mg/ml) in N,N-dimethylformamide and the mixture was rotated for 18 hours. Any remaining reagent was then reacted with 500 ul of 1M glycine and 500 ul of 10% ethanolamine for 2 hours. The coupled emulsion was then isolated by centrifugation and resuspension in fresh buffer as in Method A.
METHOD H
Bifunctional Acid Method 2
To a mixture of 2 ml of emulsion in surfactant buffer, was added 0.05 to 1.0 mg of substance to be coupled to the emulsion, and a 100 microliter aliquot of a mixture of 10 mg of a difunctional organic acid which cannot cyclize, such as fumaric or terephthalic acid and 100 microliters of carbonyl diimidizole solution (10 mg/ml) in N,N-dimethylformamide which had reacted for 15 minutes, and the mixture was rotated for 2 hours. Excess reagent was reacted with 500 microliters each of 1M glycine and 10% ethanolamine for 2 hours. The coupled emulsion was then isolated by centrifugation and resuspension in fresh buffer as in Method A.
METHOD I
Cyanate Method
To a mixture of 2 ml of emulsion in surfactant buffer and 0.05 to 1.0 mg of material to coupled to the emulsion was added 100 microliters of a p-nitrophenylcyanate solution (10 mg/ml) in N,N-dimethylformamide, and the reaction mixture was rotated for 30 minutes at room temperature. As the reaction proceeded a yellow color developed from the p-nitrophenol produced from the reaction. Then the mixture was cleaned up by the centrifugation and resuspension procedure of Method A.
EXAMPLE 11
An emulsion was prepared as in Example 7 and was coupled to a mixture of glucose oxidase and horseradish peroxidase by Method E (the Periodate Method I), above. The resulting emulsion, when exposed to glucose and substrate for peroxidase, produced color in proportion to the amount of glucose present. Using o-dianisidine (0.0021M) in 0.05M sodium acetate buffer at pH 5.1 and reference glucose solutions containing from 50 to 500 mg per dl emulsion, the linear reference curve of absorbance at 500 nanometers vs. glucose concentration was plotted indicating that the emulsion may be used to assay for glucose concentration.
EXAMPLE 12
A solution of 0.2% by weight of Tiers' Blue, a perfluoroalkylated copper phthalocyanine dye, in FC-43 was used to prepare emulsions of 1 to 10% by volume of perfluorotri-n-butylamine in phosphate-buffered saline containing 0.5% by weight Pluronic F-68 and 2 mg/ml BSA. The dispersions were effected by sonication for 5 to 10 minutes in an ice-cooled rosette cell. The emulsions were then washed by centrifugation at 30,000 g and resuspended in fresh buffersurfactant solution without BSA thrice. The resulting preparations were highly colored with a slight shift in the absorbance maximum from 610 to 612 nanometers as measured by a Beckman spectrophotometer Model 35.
EXAMPLE 13
A solution of C 8 F 17 SO 3 --C 6 H 4 N--NC 6 H 4 N(CH 3 ) 2 in perfluorotri-n-butylamine was used to prepare emulsions of 1 to 10% by volume of perfluorotri-n-butylamine in phosphate buffered saline containing 0.5% by weight Pluronic F-68 and 2 mg/ml BSA. The dispersions were effected by sonication for 5 to 10 minutes in an ice-cooled rosette cell. The emulsions were then washed by centrifugation at 30,000 g and resuspended in fresh buffered surfactant solution without BSA thrice. The washed emulsions were yellow in color, but changed to a red when the solution pH was changed to the range of 2 to 4. The color was associated only with the emulsion droplets, as was shown by centrifuging the emulsion at 30,000 g to completely remove the color from the supernatant.
Portions of the above red emulsions were combined in portions varying from 1 to 1 to 1 to 5 (by volume) of the blue emulsions from Example 12 to form several shades of purple emulsions. The combined emulsions could be changed in color from purple to green by changing the pH of the aqueous solutions.
EXAMPLE 14
Two milligrams of mouse immunoglobin (Ig) (commercially available from Cappel Laboratories, Cochranville, Pa.) was dissolved in 0.15M aqueous sodium chloride solution, and glutaraldehyde was added to provide a weight percent of 1.15%. After two hours at room temperature the activated Ig was chromatographed on Bio-Gel P-2 (commercially available from BioRad Laboratories, Richmond, Calif.) to remove excess glutaraldehyde. One milligram of the activated Ig was combined with 1 ml of a BSA emulsion from Example 7 in phosphate buffered saline of pH 9.0. After the mixture had settled for 24 hours the emulsion was washed to remove unbound Ig and the emulsion tested for immunoreactivity to anti-bovine serum albumin and anti-mouse immunoglobin by capillary immunodiffusion as described in "Handbook of Experimental Immunology", D. M. Weir, ed., Vol. 1 pp. 19.1-19.5, Blackwell Scientific Publications (1973). The results of the evaluation are shown in Table 5. When a solution of antibody is mixed with its corresponding antiserum, the antigen combines with the antibody, and if conditions are suitable, the reactants form precipitating or flocculating aggregates which are readily visible to the naked eye.
TABLE 5__________________________________________________________________________ Fluorochemical Fluorochemical Fluorochemical Emulsion with Emulsion without Emulsion with Bovine Serum Surfactant Bovine Serum Bovine Serum Albumin andAntibody Used Only Albumin Albumin Immunoglobin__________________________________________________________________________Anti-bovine - - + +serum albuminAnti-immunoblogin - - - +__________________________________________________________________________
EXAMPLE 15
A sample of the fluorochemical emulsion from Example 7 was conjugated using the method of Example 14 with Streptococcus A-carbohydrate prepared by the method described in Stanford Medical Bulletin 13, 290-291. The ability of free Streptococcus A organisms to inhibit the aggregation of the fluorochemical emulsion-bound Streptococcus A-carbohydrate mixture in the presence of an IgM monoclonal antibody was tested. A combination of the fluorochemical emulsion-bound Streptococcus A-carbohydrate, the antibody and varying concentrations of free Streptococcus A organisms was incubated for 30 minutes at about 20° C. and observed for aggregation. Aggregation was scored on a scale of zero to 4+, with zero being no inhibition of droplet aggregation and 4+ complete inhibition of droplet aggregation. The results are shown in Table 6. They indicate that this method is able to detect organisms at a level of 10 5 per milliliter.
TABLE 6______________________________________ Concentration of Aggregation Organisms InhibitionRun Number (organisms/ml) Score______________________________________1 10.sup.8 4+2 10.sup.7 4+3 10.sup.6 3+4 5 × 10.sup.5 3+5 10.sup.5 1+6 5 × 10.sup.4 07 10.sup.4 08 10.sup.3 0______________________________________ | 4y
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FIELD OF THE INVENTION
[0001] The present invention is directed to a post print finishing device in which imaging material is used to bind a printed documented.
BACKGROUND OF THE INVENTION
[0002] Current devices and methods for printing and binding media sheets involve printing the desired document on a plurality of media sheets, assembling the media sheets into a stack, and separately stapling, clamping, gluing and/or sewing the stack. In addition to imaging material used to print the document, each of these binding methods require separate binding materials, increasing the cost and complexity of binding. Techniques for binding media sheets using imaging material are known in the art. These techniques generally involve applying imaging material such as toner to defined binding regions on multiple sheets, assembling the media sheets into a stack, and reactivating the imaging material, causing the media sheets to adhere to one another.
[0003] The present invention was developed to integrate an imaging material binder into a post print finishing device such as the stapler/stacker devices commonly used with middle to high end printers and copiers. The modular implementation shown in the drawings and detailed below was developed for use in the Hewlett-Packard Company model C8085A stapler/stacker with the imaging material binder module replacing the stapler module. Various techniques and structural configurations for binding documents using imaging material are described in U.S. patent application Ser. No. 09/320,060, filed May 26, 1999 titled Binding Sheet Media Using Imaging Material, Ser. No. 09/482,124, filed Jan. 11, 2000 titled Apparatus and Method For Binding Sheet Media, and Ser. No. 09/866,017, filed May 24, 2001 titled Apparatus and Method for Binding Sheet Media, all of which are incorporated herein by reference in their entirety.
[0004] When imaging material binding is used, each sheet of paper or other print media includes imaging material, such as toner, applied to one or more selected binding regions in addition to the print image applied to each sheet. The binding regions are usually located along one edge of the media sheet on one or both sides. All of the imaging material applied to the sheet is activated as part of the print process. The imaging material applied to the binding region(s) is reactivated in the binder to bind the multiple sheets of a document together. The bound document may be formed by reactivating the imaging material in a stack of sheets in the document at the same time or by individually binding each sheet one after another to the stack. The strength of the inter-sheet bond is a function of the type, area, density, and degree of reactivation of the imaging material applied to the binding region of each sheet. By varying these parameters the inter-sheet bond can be made very strong to firmly bind the document or less strong to allow easy separation. When the imaging material is toner, such as that used in laser printers, the imaging material will usually be reactivated by applying heat and pressure as in the exemplary embodiment of the invention detailed below. Other imaging materials and reactivation techniques may also be used, such as those described in the '060 application.
SUMMARY OF THE INVENTION
[0005] Accordingly, the present invention is directed to a post print finishing device that incorporates an imaging material binder into the post print handling and finishing functions. In one exemplary embodiment of the invention, the finishing device includes a flipper module, an accumulator module and a binder module. The binder module binds sheets together by reactivating imaging material applied to binding regions on the sheets by a printing device. The flipper module receives a sheet leading edge first and discharges the sheet trailing edge first. That is to say, the flipper module flips the sheet before discharging the sheet for further processing. The accumulator module stacks the sheets, presents the sheets to the binder for binding and then discharges the bound stack to the output bin.
DESCRIPTION OF THE DRAWINGS
[0006] [0006]FIG. 1 is a perspective view of a printer and attached stacker illustrating one type of document printing and finishing system in which the invention may be implemented.
[0007] [0007]FIG. 2 is a side elevation view of a modular stacker constructed according to one embodiment of the invention showing the flipper, paper path, accumulator and binder modules.
[0008] FIGS. 3 - 10 are side elevation views showing the routing of media sheets through the stacker of FIG. 2. FIG. 3 shows a sheet routed to the upper/single sheet output bin. FIGS. 4 - 7 show a sheet routed to the stack of sheets in the accumulator in preparation for binding. FIGS. 8 - 10 show the stack routed to the binder, bound and then discharged to the lower/stacker output bin.
[0009] [0009]FIG. 11 is a detailed perspective view of the binder module of FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
[0010] The invention will be described with reference to the printer 10 and attached stacker 12 shown in FIG. 1. The invention may be implemented in any document production system in which it is necessary or desirable to use an imaging material binder. Printer 10 and stacker 12 , therefore, represent generally any suitable printing device (e.g., printers, copiers, and multi-function peripherals) and associated post print finishing device in which imaging material is used to bind a printed documented.
[0011] Referring to FIG. 1, printer 10 and stacker 12 together make up a document production system designated generally by reference number 14 . Printed sheets are output by printer 10 to stacker 12 where they are routed to an upper/loose sheet output bin 16 or to a lower/stacker output bin 18 . Unbound sheets are collected face up in loose sheet bin 16 . Bound documents are collected face down in stacker bin 18 .
[0012] A stacker 12 constructed according to one embodiment of the invention will now be described with reference to FIG. 2. FIG. 2 is a side elevation view looking into stacker 12 showing the flipper module 20 , paper path module 22 , accumulator module 24 and binder module 26 . Each module is mounted to a frame 28 . Frame 28 , which forms the main body or “skeleton” of stacker 12 , is made from sheet metal or other suitable structurally stable materials. A power supply 30 and controller 32 are mounted to the lower portion of frame 28 . Power supply 30 and controller 32 are electrically connected to the operative components of modules 20 , 22 , 24 and 26 . Controller 32 contains the electronic circuitry and programming necessary to control and coordinate various functions of the components in stacker 12 . The details of the circuitry and programming of controller 32 are not particularly important to the invention as long as the controller design is sufficient to direct the desired functions as described below.
[0013] The modular design of stacker 12 shown in FIG. 2 is adapted from the Hewlett-Packard Company model C8085A stapler/stacker. Each module 20 , 22 , 24 and 26 is operatively coupled to but otherwise independent of the adjacent module. In the stacker of the present invention, the stapler module used in the C8085A stapler/stacker is replaced with binder module 26 and controller 32 is modified accordingly to control the operation of an imaging material binder rather than a stapler.
[0014] For sheets that will be stacked, bound and output to bin 18 , flipper 20 makes the leading edge of each sheet output by printer 10 the trailing edge for routing to paper path 22 and accumulator 24 . Flipping the sheets in this manner from face up to face down is necessary to properly stack the sheets in accumulator 24 prior to binding. Paper path 22 moves each sheet face down to accumulator 24 where the sheets are collected, registered, moved to binder 26 (when binding is desired) and then output to bin 18 (bound or unbound). Binder 26 reactivates the imaging material applied to select binding regions on sheets collected in accumulator 24 to bind the sheets together.
[0015] The operation of flipper 20 , paper path 22 , accumulator 24 and binder 26 will now be described in more detail with reference to FIGS. 3 - 10 . FIG. 3 shows a sheet routed to loose sheet bin 16 . FIGS. 4 - 7 show a sheet routed to accumulator 24 in preparation for binding. FIGS. 8 - 10 show the stack routed to binder 26 , bound and then ejected to stacker bin 18 .
[0016] Referring to FIG. 3, a sheet of paper or other print media 34 is output by printer 10 to stacker 12 through printer output rollers 35 and received into flipper 20 through flipper receiving port 37 . As flipper entry sensor 36 detects sheet 34 entering flipper 20 , flipper entry rollers 38 and flipper tray rollers 40 are driven forward as indicated by arrows 42 to move sheet 34 toward bin 16 . For sheets routed to loose sheet bin 16 through flipper discharge port 39 , rollers 38 and 40 are continually driven forward until sheet 34 reaches bin 16 . In the embodiment shown in the Figures, flipper entry rollers 38 and flipper out rollers 44 share the same drive roller 46 . Drive roller 46 is movable up or down to engage an opposing idler roller as necessary to move sheet 34 along one of two desired paper paths, as best seen by comparing FIGS. 3 and 4.
[0017] Referring now to FIG. 4, for sheets routed to accumulator 24 , flipper entry and tray rollers 38 and 40 are driven forward until just after the trailing edge of sheet 34 clears flipper entry rollers 38 , as detected by flipper middle sensor 48 , such that the trailing edge of sheet 34 clears directional guide 50 . Then, drive roller 46 is moved down to flipper out roller 44 and reversed along with flipper tray rollers 40 to route sheet 34 toward paper path 22 through flipper routing port 41 and paper path receiving port 53 . Paper path rollers 52 move sheet 34 through paper path 22 down to accumulator 24 . Flipper exit sensor 54 detects when sheet 34 has cleared the flipper module 20 . Paper path exit sensor 56 detects when sheet 34 has cleared the paper path module 24 through paper path discharge port 55 . Exit sensors 54 and 56 are used to control paper path rollers 52 . When paper path exit sensor 56 detects that sheet 34 is leaving the paper path module 24 , then paper path rollers 52 are stopped unless another sheet has cleared the flipper module 20 as detected by flipper exit sensor 54 .
[0018] Referring to FIGS. 5 - 7 , sheet 34 is guided down from accumulator receiving port 59 through accumulator 24 to accumulator entry rollers 58 and on to accumulator eject rollers 60 . An accumulator entry sensor 62 is positioned immediately upstream from entry rollers 58 . As the trailing edge of sheet 34 passes through entry rollers 58 , as detected by entry sensor 62 , eject rollers 60 move the top sheet 34 back on to stack 64 in accumulator holding tray 66 , as best seen by comparing FIGS. 5, 6 and 7 . In the embodiment shown in the Figures, eject rollers 60 are configured as a pair of variably spaced rollers that are selectively driven as necessary to move top sheet 34 or stack 64 . As shown in FIGS. 5 and 6, eject rollers 60 are spaced apart or “open” to receive top sheet 34 . Then, the rollers come together and the top roller is driven counterclockwise to move top sheet 34 on to stack 64 , as shown in FIG. 7. Eject rollers 60 are driven together, as shown in FIGS. 8 and 10, counter-clockwise to move stack 64 into binder 76 (FIG. 8) or clockwise to move stack 64 into lower output bin 18 (FIG. 10). Although not shown, at the same time each sheet 34 is routed to holding tray 64 , sheet 34 is aligned with the other sheets in stack 66 .
[0019] A binding operation will now be described with reference to FIGS. 8 - 11 . Referring to FIG. 8, once all the sheets in the document are accumulated in stack 64 , eject rollers 60 draw stack 64 back slightly from registration wall 68 , registration wall 68 is dropped and eject rollers 60 are reversed to move the edge of stack 64 forward into binder 26 through accumulator binding port 63 . Retainer 70 is then lowered against stack 64 to hold stack 64 in position during binding.
[0020] Referring now also to FIG. 11, binder 26 includes mounting brackets 72 , reversible motor 74 (not shown in FIG. 11) and press 76 . Press 76 includes base 78 , carriage 80 , top support plate 82 , lead screw 84 and gear 86 . Motor 74 is operatively connected to carriage 80 through gear 86 and lead screw 84 . Carriage 80 moves alternately toward and away from base 78 along guide posts 90 at the urging of motor 74 . Base 78 and carriage 80 are constructed as heated platens by, for example, applying resistive heating strips 88 along opposing surfaces of base 78 and carriage 80 . Preferably, both platens (base 78 and carriage 80 ) are heated when all sheets in the stack are bound at the same time. Only the top platen (carriage 80 ) needs to be heated when each page or small numbers of pages are bound to the stack using page by page binding techniques such as those described in the '124 application referenced in the Background.
[0021] Base 78 and carriage 80 , the binder platens, form an opening immediately adjacent to accumulator holding tray 66 . Preferably, holding tray 66 and platens 78 and 80 are aligned at substantially the same angle to allow stack 64 to move easily into the opening between platens 78 and 80 . Once the edge of stack 64 is positioned in binder 26 , heating strips 88 are activated and motor 74 is energized to close press 76 by driving carriage 80 against stack 64 and base 78 , as shown in FIG. 9. Heat and pressure are thereby applied to the imaging material applied by printer 10 to the binding region along the edge of the sheets in stack 64 . Motor 74 is then reversed to open press 76 by driving carriage 80 away from stack 64 and base 78 . Retainer 76 is raised off the now bound stack 64 , ejector rollers 60 are reversed again to route the bound stack 64 through accumulator discharge port 61 to stacker bin 18 , and registration wall 68 is raised in preparation for stacking the next print job, as shown in FIG. 10.
[0022] While the present invention has been shown and described with reference to the foregoing exemplary embodiment, it is to be understood that other forms, details, and embodiments may be made without departing from the spirit and scope of the invention which is defined in the following claims. | 4y
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[0001] This application claims priority of U.S. Provisional Patent Application Ser. No. 60/529,370 filed Dec. 11, 2003.
FIELD OF THE INVENTION
[0002] This invention relates to valve systems, and more particularly, to valve position monitors in actuated valve systems.
BACKGROUND OF THE INVENTION
[0003] Various industries utilize actuated valve systems. For example, in the pharmaceutical manufacturing industry, actuated valve systems are utilized to control fluid flow. Such actuated valve systems are also used in a variety of alternative industries, including biotechnology industries, laboratories, etc. In such industries it is desirable to know the status of the valve (i.e., open or closed). Various valve position indicators are available for use on pneumatically actuated linear valves. However, these indicators suffer from a number of deficiencies.
[0004] One problem is that the indicators are typically undesirably quite large as compared to the size of the valve's actuator. Additionally, because such indicators are often integrated into existing valve systems, portions of the indicator are exposed. Such exposure can lead to damage to the indicator or remainder of the valve system during certain operations (e.g., during a process washdown).
[0005] Yet another problem with existing position indicators is the potential for false position feedback. In many instances, minor fluctuations in actuator pressure, diaphragm wear inside the valve, or external stresses on the switch package can cause misalignment between a signal trigger and a sensor or switch. This misalignment can cause the operator to get a false position signal.
[0006] Thus, it would be desirable to provide a actuated valve indicator system overcoming one or more of the above-described deficiencies.
SUMMARY OF THE INVENTION
[0007] In accordance with an exemplary embodiment of the present invention, a valve system is provided. The valve system includes a valve assembly and an actuator for operating the valve assembly. The actuator includes a housing and a shaft extending through the housing. The shaft is moveable within a range of motion during operation of the valve assembly. The valve system also includes a valve position monitor for monitoring the position of the valve assembly. The valve position monitor includes at least one trigger and a corresponding stationary stop. The trigger is moveable with respect to the stationary stop within a range of motion. The range of motion of the trigger corresponds to at least a portion of the range of motion of the shaft. At least a portion of the range of motion of the trigger extends into the housing of the actuator.
[0008] In accordance with another exemplary embodiment of the present invention, a method of assembling a valve system including a valve assembly is provided. The method includes providing an actuator for operating the valve assembly, where the actuator includes a housing and a shaft extending through the housing, and the shaft is moveable within a range of motion during operation of the valve assembly. The method also includes coupling a valve position monitor for monitoring the position of the valve assembly to the actuator, where the valve position monitor includes at least one trigger and a corresponding stationary stop. The trigger is moveable with respect to the stationary stop within a range of motion, where the range of motion of the trigger corresponds to at least a portion of the range of motion of the shaft. The coupling step includes extending at least a portion of the range of motion of the trigger into the housing of the actuator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Exemplary embodiments of the invention will be described with reference to the drawings, of which:
[0010] FIG. 1 is a front view of an actuated valve system including a valve position monitoring device in accordance with an exemplary embodiment of the present invention;
[0011] FIG. 2 is a cut-away front view of an actuated valve system in an open position including a valve position monitoring device in accordance with an exemplary embodiment of the present invention;
[0012] FIG. 3 is a cut-away front view of an actuated valve system in a closed position including a valve position monitoring device in accordance with an exemplary embodiment of the present invention; and
[0013] FIG. 4 is a cut-away top view of an actuated valve system including a valve position monitoring device in accordance with an exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Preferred features of embodiments of this invention will now be described with reference to the figures. It will be appreciated that the spirit and scope of the invention is not limited to the embodiments selected for illustration. Also, it should be noted that the drawings are not rendered to any particular scale or proportion. It is contemplated that any of the configurations and materials described hereafter can be modified within the scope of this invention.
[0015] As will be explained herein, according to certain exemplary embodiments of the present invention, an electric field is emitted (e.g., using a DC supply such as 24 V DC) and sensed by at least one proximity sensor. When the at least one sensor senses the electric field at or beyond a certain threshold level, the sensor provides a signal indicating that the valve is in a given position (e.g., open, closed, partially open, partially closed, etc.). Is Alternatively, if the electric field has collapsed (e.g., because of a ferrous material moving into a position to violate the field), the at least one sensor senses the electric field at or below another threshold level, and the sensor provides a signal indicating that the valve is in another position (e.g., open, closed, partially open, partially closed, etc.).
[0016] The output signals provided from the sensor(s) may be used to actuate a local indication flag/beacon at the valve, and/or may be transmitted remotely (e.g., to a central control system such as a DCS). The output signals may be current-based. For example, based on the level of the sensed electric field, a higher or lower amount of current is provided in the output signals from the sensor(s). This amount of current equates to a position of the valve.
[0017] As will be explained herein, the valve of the present invention is assembled by an operator such that the valve position monitoring device advantageously realigns itself. Further, a valve position monitoring device with a low profile is provided, thereby resulting in a actuated valve system with a low profile. Further still, a modular valve position monitoring device that is integrated with the valve's actuator is provided.
[0018] FIG. 1 is a front view of an actuated valve system 100 . Actuated valve system 100 includes valve assembly 3 (i.e., the valve itself), actuated valve assembly 2 (i.e., a valve actuator), and valve position monitoring device 1 . Actuated valve assembly 2 operates valve assembly 3 . For example, actuated valve assembly 2 is a pneumatically actuated assembly. Valve position monitoring device 1 (a.k.a. a “Switch Pack”) includes sensor carrier area 6 and cover 4 . Also illustrated in FIG. 1 is connector 10 (e.g., an M12 connector), which receives a number of conductors for signaling and other functions.
[0019] FIG. 2 is a cut-away front view of actuated valve system 100 in an open position, with valve assembly 3 substantially removed. As illustrated in FIG. 2 , pneumatically actuated valve assembly 2 is integrated with valve i 5 position monitoring device 1 . More specifically, as will be explained herein, a portion of valve position monitoring device 1 extends into pneumatically actuated valve assembly 2 . This advantageously results in an actuated valve system having a lower profile.
[0020] Valve position monitoring device 1 includes sensor carrier 6 , cover 4 , OPEN target 7 , CLOSED target 8 , proximity sensors 5 (i.e., OPEN sensor 5 a and CLOSED sensor 5 b ), an OPEN stop 9 , and shaft 13 (i.e., indicating spindle 13 ). As used in the art, the terms target and trigger refer to the same structure. In embodiments using a ferrous material to interrupt an electric field as described above, the targets would include such a material. In the exemplary embodiment illustrated in FIG. 2 , OPEN target 7 and CLOSED target 8 are mounted on shaft 13 and are held in place via friction.
[0021] When actuated valve system 100 is cycled, shaft 13 moves up and/or down) within its range of motion. To a certain extent, OPEN target 7 and CLOSED target 8 move along with shaft 13 ; however, at certain positions, movement of the targets is impeded by “stops.” For example, OPEN target 7 may move upwardly along with shaft 13 until OPEN target 7 is “stopped” by OPEN stop 9 . Likewise, CLOSED target may move downwardly along with shaft 13 until CLOSED target is “stopped” by CLOSED stop 9 a . Thus, OPEN target 7 and CLOSED target 8 each move within their respective ranges of motion that are within the range of motion of shaft 13 .
[0022] Valve position monitoring device 1 may also include solenoid 12 (e.g., a 3/2 solenoid illustrated in FIG. 4 ) for actuating the valve, and printed circuit board 11 (also illustrated in FIG. 4 ). For example, printed circuit board 11 provides an interconnection point between sensor(s) 5 and output wiring transmitting the valve position. Printed circuit board 12 may also act as an interconnection point between solenoid 10 and associated control wiring. Thus, wiring between internal components of valve position monitoring device 1 (e.g., sensor(s) 5 , solenoid 12 ) and external circuitry (e.g., control circuitry, monitoring circuitry, control system interface circuitry) is brought into actuated valve system 100 via field wiring extending through connector 10 .
[0023] Printed circuit board 11 may also include electronics for facilitating monitoring and/or control via a network bus system for use with a control system (e.g., a distributed control system, a man-machine interface, etc.). For example, such a network bus system may be AS-Interface protocol or DeviceNet protocol compatible.
[0024] In FIG. 2 , the valve assembly 3 (not illustrated) is in the OPEN position. As shown in FIG. 2 , OPEN target 7 is in contact with OPEN stop 9 , and as such, OPEN target 7 is at the highest point in its range of motion. Further, the lower portion of OPEN target 7 is visibly aligned with the lower portion of OPEN sensor 5 a. Thus, it is clear that valve assembly 3 (not illustrated) is in the OPEN position. Further, as shown in FIG. 2 , closed target 8 is not at the bottom of its range of motion (closed target 8 is not in contact with CLOSED stop 9 a ), and the lower portion of CLOSED target 8 is not visibly aligned with the lower portion of CLOSED sensor 5 b. Thus, it is clear that valve assembly 3 (not illustrated) is not in the CLOSED position.
[0025] In contrast, in FIG. 3 , the valve assembly 3 is in the CLOSED position. As shown in FIG. 3 , closed target 8 is at the bottom of its range of motion (closed target 8 is in contact with CLOSED stop 9 a ), and the lower portion of CLOSED target 8 is visibly aligned with the lower portion of CLOSED sensor 5 b. Thus, it is clear that valve assembly 3 is in the CLOSED position. Further, as shown in FIG. 3 , OPEN target 7 is not in contact with OPEN stop 9 , and as such, OPEN target 7 is not at the highest point in its range of motion. Further, the lower portion of OPEN target 7 is visibly not aligned with the lower portion of OPEN sensor 5 a. Thus, it is clear that valve assembly 3 is not in the OPEN position.
[0026] As provided above, in certain embodiments of the present invention, an electric field generated through at least one conductor extending through connector 10 (conductors are not shown in the Figures) provides a signal for receipt by sensors 5 . For example, in FIGS. 2-3 , a lower portion of each of sensor 5 a and 5 b include a sensing portion for sensing the electric field.
[0027] Each of targets 7 and 8 include a ferrous material (e.g., in the form of a ferrous band). For example, in the embodiments illustrated in FIGS. 2-3 , the lower portion of OPEN target 7 includes such a ferrous band, and substantially the entire cross section of CLOSED target 8 includes such a ferrous band. Thus, in FIG. 2 , the ferrous band included in OPEN target 7 is blocking the sensing portion of OPEN sensor 5 a, thereby collapsing the electric field, and resulting in an OPEN signal being transmitted. Likewise, in FIG. 2 , the ferrous band in CLOSED target 8 is not blocking the sensing portion of CLOSED sensor 5 b, and as such, the electric field is not collapsed, resulting in no CLOSED signal being transmitted.
[0028] Conversely, in FIG. 3 , the ferrous band included in OPEN target 7 is not blocking the sensing portion of OPEN sensor 5 a, and as such, the electric field is not collapsed, resulting in no OPEN signal being transmitted. Likewise, in FIG. 3 , the ferrous band in CLOSED target 8 is blocking the sensing portion of CLOSED sensor 5 b, and as such, the electric field is collapsed, resulting in a CLOSED signal being transmitted.
[0029] FIG. 4 is a cut-away top view of actuated valve system 100 with cover 4 removed. Features illustrated in FIG. 4 include shaft 13 , proximity sensor(s) 5 , printed circuit board 11 , and solenoid 12 .
[0030] To assemble actuated valve system 100 to include valve position monitoring device 1 , at least one proximity sensor 5 is mounted in sensor carrier 6 . Connector 10 , printed circuit board 11 (e.g., including a terminal strip), and solenoid 12 , are also mounted onto/into sensor carrier 6 . Sensor carrier 6 is mechanically fastened to actuated valve assembly 2 with shaft 13 protruding through a center hole in actuated valve assembly 2 . CLOSED target 8 is then pushed onto shaft 13 . OPEN target 7 and OPEN stop 9 are installed in a similar fashion. Electrical connections are also made.
[0031] To calibrate valve position monitoring device 1 , an individual (e.g., an operator) pushes down on the OPEN target 7 until it hits a stop (i.e., CLOSED stop 9 a ). Then, the individual pulls up on OPEN target 7 until another stop is reached (e.g., OPEN stop 9 ). Cover 4 may then be installed (e.g., through a threading operation).
[0032] After calibration of valve position monitoring device 1 , when valve assembly 3 and actuated valve assembly 2 are cycled, OPEN target 7 and CLOSED target 8 will self-align in front of proximity sensors 5 . This self alignment is facilitated through the frictional coupling of OPEN target 7 and CLOSED target 8 with shaft 13 . As stated above, when shaft 13 moves up and down during valve cycling, OPEN target 7 and CLOSED target 8 move up and down through the frictional coupling until they contact their corresponding stops. Thus, during cycling, OPEN target 7 and CLOSED target 8 realign through contact with their corresponding stops.
[0033] Depending on the configuration provided, the valve position can be monitored through a number of methods including, but not limited to, (a) visual monitoring of a local flag/beacon at the valve, (b) monitoring, either manually or through a control system, changes in the signal current from the sensors, or (c) monitoring of a network system, for example, using AS-Interface or DeviceNet protocol.
[0034] By integrating the range of motion of at least one of OPEN target 7 and CLOSED target 8 to be at least partially within actuated valve assembly 2 , a reduced profile of the valve system is achieved. In existing switch pack technology, a manufacturer and/or provider of a valve actuator is typically different from a manufacturer and/or provider of a switch pack. Thus, the switch pack is designed to work with an existing valve actuator design, and often this results in a less than desirable configuration. According to the present invention, the actuated valve assembly 2 is designed with the position monitoring device 1 in mind. Thus, space within actuated valve assembly 2 is provided to integrally accept a portion of position monitoring device 1 .
[0035] Additionally, a modular valve position monitoring device 1 is provided for providing valve position feedback signals. This modular valve position monitoring device 1 is relatively easy to assemble, service and/or replace in comparison to existing switch packs.
[0036] Although the present invention has been primarily described in terms valve position monitoring device 1 including two sensors 5 (i.e., an OPEN sensor and a CLOSED sensor), it is not limited thereto. A single sensor may be used to indicate a single position (e.g., OPEN or CLOSED) which may be adequate in certain applications. Alternatively, more than two sensors (e.g., redundant sensors) may be utilized in certain applications where valve position information is critical.
[0037] Although the present invention has been primarily described in terms using the existence or collapse of an electric field to generate valve position signals, it is not limited thereto. Various methods of determining the valve position are contemplated, so long as a portion of the range of motion of valve position monitoring device 1 extends into actuated valve assembly 2 . Thus, although positioning of ferrous bands included in the moving targets are disclosed for collapsing the electric field, this configuration is exemplary in nature. Alternative embodiments with different ferrous material configurations (i.e., not a band), or without a ferrous material at all, are also contemplated.
[0038] Although the present invention has been primarily described in terms of pneumatically-actuated valves, it is not limited thereto. The principles disclosed herein apply to a variety of actuation systems including, but not limited to, electrically actuated, mechanically actuated, and other actuation systems.
[0039] Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention. | 4y
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Application No. 60/254,321 filed on Dec. 11, 2000, and U.S. Provisional Patent Application 60/326,080 filed Sep. 28, 2001 which are hereby incorporated by reference as if set forth in full herein.
BACKGROUND OF THE INVENTION
[0002] This invention relates generally to gaming printers and more specifically to gaming printers with print verification features.
[0003] The gaming machine manufacturing industry provides a variety of gaming machines for the amusement of gaming machine players. An exemplary gaming machine is a slot machine. A slot machine is an electro-mechanical game wherein chance or the skill of a player determines the outcome of the game. Slot machines are usually found in casinos or other more informal gaming establishments.
[0004] Gaming machine manufacturers have introduced the use of a gaming printer allowing the printing of a voucher for a player's winnings when the player cashes out. The gaming printer may be resident in a slot machine or made available to a bank of slot machines via a gaming system. The voucher can either be redeemed with a cashier or redeemed by inserting the voucher into the same or another slot machine for playing credit, as if the voucher were money. The gaming printer's role, therefore, is to print out winnings thereby avoiding the need for the slot machine to dispense coins with each pay-out or jackpot won.
[0005] Gaming printers may be implemented using dot impact printers and thermal printers. Dot impact printers, also known as impact printers, are printers that make an image by striking an inked ribbon overlaid on plain paper with a small pin that hammers the ink onto the paper to make a small dot. Impact printers, by their electro-mechanical nature, have a number of moving parts and make a characteristic grinding sound, such as the noise made by all older receipt printers. A thermal printers is a printer where paper with a heat sensitive side is imaged using a print head which applies heat in tiny dots (typically {fraction (1/200)} th of an inch in size) in order to turn an area black. In this manner, all images are created by a series of tiny black dots. A widely known example of a thermal printer is the original fax machine.
[0006] The gaming printer may be controlled by a Gaming Machine Interface Board (GMIB) such as a slot machine interface board which is a controller board for a game resident within the chassis of the game. The gaming printer may be controlled by commands sent from a host controller board such as a GMIB, or another host controller board upstream of the slot machine in order to print vouchers.
[0007] Anytime there an electro-mechanical device such as a gaming printer, there is a chance of an equipment failure that leaves the desired printing operation unaccomplished. For a thermal printer used as a gaming printer, such a failure can occur for a number of reasons: (i) the printer experiences a hardware failure; (ii) a residue or heat transfer failing which prevents a proper image from developing on the thermal paper ticket; or (iii) a failure in the paper coating process at the factory so that there is a drop out on the printed image.
[0008] Any of the above failures may prevent the ticket from printing completely. Since a voucher, sometimes with a value of $1,000 or more is being dispensed (as opposed to real currency), it is very important that the voucher delivery and redemption process is highly reliable to allay a player's fear about the handling of their “money”. After a voucher is printed, the voucher can be redeemed with a cashier or the voucher can be redeemed through a slot machine's bill acceptor. A bill acceptor is a device which automatically accepts paper currency by scanning the paper currency and saving the paper currency within the slot machine. A coin change machine usually has such a device on it, and more recently, so do most slot machines. The standard vouchers for this application usually bear a barcode down the center of the voucher so that the voucher can be read automatically by the bill acceptor.
[0009] In order for the bill acceptor to properly scan the ticket, there must not be an error in the printing of the barcode, or the process will fail. Any of the previously itemized printing failures may cause the barcode to contain an error. Should such an error occur, the ticket cannot be redeemed, requiring significant casino resources to validate and hand pay the player (who at this point is probably quite nervous and has lost some of the thrill of the act of winning). A hardware failure of the printer may be detected by the communications with the GMIB, and thus an attendant may be alerted ahead of the pay out. However, previously described failure modes (ii) and (iii) are modes which may prevent the printing of a full image on the ticket and may not be detected by the GMIB or the printer. An undetected error may leave an operator of a slot machine to believe that a complete and proper pay out has been made.
[0010] Previous attempts of verification have focused on the verification of the cashout value. For example, U.S. Pat. No. 6,012,832 issued to Saunders, et al. entitled “CASHLESS PERIPHERAL DEVICE FOR A GAMING SYSTEM” discloses a method of verifying a cashout value encoded in a barcode. In the method, The cashout value is read immediately after the voucher is printed and the voucher is withheld if a printing error is detected. However, only verifying a cashout value does not fully address the verification needs of a casino. In a casino, when a player wishes to cashout with a cashier, the cashier hand enters a validation character string printed on the voucher into a terminal for verification. When a gaming machine management system verifies the entered validation character string, the voucher is paid.
[0011] Therefore, a need exists for verification of the printing of a validation character string on a voucher.
SUMMARY OF THE INVENTION
[0012] In one aspect of the invention, a method is provided for verification of a voucher after printing by a gaming printer. A human readable validation character string is received by a printer controller for printing on a voucher. A scanned validation character string is read from the voucher using an optical recognition process as the voucher is being printed. The voucher is verified by comparing the received and scanned validation character strings. If the two validation character strings are different, the voucher may be voided by the printer controller before the voucher is finished being printed.
[0013] In another aspect of the invention, a method is provided for verification of a voucher by a gaming printer. A printer controller receives a validation character string and prints the received validation character string on a voucher. The printer controller scans the voucher for a scanned validation character string and verifies the voucher using the received validation character string and the scanned validation character string.
[0014] In another aspect of the invention, the received validation character string is generated by a gaming machine interface board.
[0015] In another aspect of the invention, the received validation character string is received from a gaming machine management system.
[0016] In another aspect of the invention, the scanned validation character string is generated using an optical character recognition process.
[0017] In another aspect of the invention, the optical character recognition process is performed by a printer controller.
[0018] In another aspect of the invention, the optical character recognition process is performed by a voucher scanning device.
[0019] In another aspect of the invention, the voucher is verified by comparing the received validation character string and the scanned validation character string.
[0020] In another aspect of the invention, the voucher is voided if voucher is not verified.
[0021] In another aspect of the invention, the voucher is scanned while the voucher is being printed.
[0022] In another aspect of the invention, an apparatus is provided for verification of a voucher by a gaming printer. The apparatus includes means for receiving a validation character string and printing the received validation character string on a voucher. The apparatus further includes means for scanning the voucher for a scanned validation character string and means for verifying the voucher using the received validation character string and the scanned validation character string.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
[0024] [0024]FIG. 1 is an illustration of an exemplary validation character string verification system in accordance with the present invention;
[0025] [0025]FIG. 2 is an illustration of an exemplary voucher in accordance with the present invention;
[0026] [0026]FIG. 3 is an illustration of an exemplary gaming printer in accordance with the present invention;
[0027] [0027]FIG. 4 is an illustration of an exemplary gaming printer incorporated into an exemplary gaming machine management system in accordance with the present invention; and
[0028] [0028]FIG. 5 is a process flow diagram of a validation character string verification process in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0029] [0029]FIG. 1 is an illustration of an exemplary validation character string verification system in accordance with the present invention. A validation character string verification system 10 includes a printer controller 12 operatively coupled to a print head 14 and a voucher scanning device 24 . The printer controller uses the print head to print a voucher 18 including a validation character string 22 . As the voucher is being printed, the printer controller uses the voucher scanning device to scan the previously printed validation character string. If the printer controller determines that the scanned validation character string has an error, then the printer controller voids or retrieves the voucher.
[0030] In slightly more detail, the printer controller transmits print head control signals 16 to the print head. The print head control signals include voucher printing instructions for generation of the voucher by the print head. The print head uses the voucher printer instructions to print the voucher including a barcode 20 and the validation character string.
[0031] In one embodiment of a voucher in accordance with the present invention, the barcode is an encoded validation character string. In another embodiment of a voucher in accordance with the present invention, the barcode is an encoded cashout value for the voucher and the validation character string is a separate character string or number used to validate the voucher.
[0032] The voucher scanning device scans the voucher as the voucher is being printed by the print head. In one embodiment of a voucher scanning device in accordance with the present invention, the voucher scanning device is a Charged-Coupled Device (CCD) optical scanner. The voucher scanning device transmits voucher scan signals 26 to the printer controller. In one embodiment of a voucher scanning device, the voucher scan signals are unprocessed and the printer controller uses an optical character recognition (OCR) process to generate a scanned validation character string from the voucher scan signals. In another embodiment, the voucher scanning device includes an OCR process and the voucher scan signals include the recognized characters of the scanned validation character string.
[0033] In one embodiment of a validation character string verification system in accordance with the present invention, a GMIB 28 is operably coupled to the printer controller. The printer controller receives printer control instructions 30 from the GMIB. The printer control instructions include the validation character string to be printed by the printer controller on the voucher. The printer controller generates voucher verification signals 32 indicating whether or not the voucher has been verified. The printer controller transmits the voucher verification signals to the GMIB. The GMIB uses the voucher verification signals to determine if the voucher was correctly printed.
[0034] [0034]FIG. 2 is an illustration of an exemplary voucher in accordance with the present invention. Validation character strings may appear in a plurality of locations on a voucher and in a plurality of orientations. In one embodiment of a voucher, a validation character string 22 is printed near and substantially parallel to a leading edge 200 of the voucher. In another embodiment of a voucher, a validation character string 202 is located near and substantially parallel to a barcode 20 . In another embodiment of a voucher, the voucher includes a single validation character string in a plurality of locations and a plurality of orientations.
[0035] The validation character string may be any sequence of human readable characters. In one embodiment of a validation character string, the validation character string includes numeric characters with interspersed spaces and dashes. In another embodiment of a validation character string, the validation character string includes alphanumeric characters.
[0036] [0036]FIG. 3 is an illustration of an exemplary gaming printer including an exemplary validation character string verification system in accordance with the present invention. A gaming printer 300 includes a printing mechanism 301 . The printing mechanism includes a print head 14 for printing vouchers and a voucher scanning device 24 for scanning a validation character string. In one embodiment of a validation character string verification system, the print head and voucher scanning device are physically located such that the voucher scanning device can scan the voucher for the validation character string and a printer controller can finish a verification process of the validation character string before the print head has finished printing the voucher. In another embodiment of a validation character string verification system, the printer can invalidate the voucher before the voucher leaves the printer mechanism. In another embodiment of a validation character string verification system, the printer can retrieve a voucher so that a player cannot obtain the voucher if the voucher fails the verification process.
[0037] [0037]FIG. 4 is an illustration of an exemplary gaming printer incorporated into an exemplary gaming machine management system in accordance with the present invention. A gaming machine management system 400 , such as a slot machine management system, is operably coupled to a plurality of gaming machines 402 , 404 , by a communications network 405 adapted for communications using a variety of protocols. The gaming machine management system is further operably coupled to a cashier's terminal 408 . In operation, a player 412 plays the gaming machine and requests a cashout voucher (not shown). The gaming machine uses a gaming printer 300 to print a cashout voucher including a validation character string. The player takes the voucher to a cashier 414 . The cashier uses the cashier terminal to enter the validation character sting included in the voucher into the gaming machine management system. The gaming machine management system validates the voucher for the cashier. If the gaming machine management system validates the voucher using the validation character string, the cashier pays the player the cashout value of the voucher.
[0038] In one embodiment of a gaming machine management system, the gaming machine management system is operably coupled to a gaming machine via a GMIB 28 . The GMIB receives gaming machine management system signals transmitted by the gaming machine management system for management of the functions of a gaming machine. Additionally, the GMIB transmits gaming machine status signals to the gaming machine management system. For example, the GMIB receives voucher verification signals generated by the previously described voucher verification process as implemented within the gaming printer. If a voucher fails the verification process, the validation character string is transmitted to the gaming machine management system for further processing such as alerting casino personnel.
[0039] In one embodiment of a gaming machine management system, the validation character string represents an account identifier generated by the gaming machine management system for cashout transactions. The validation character string is associated with an account wherein a monetary amount equal to the value of a voucher's cashout value is stored. In this embodiment, the validation character string is used by the cashier to access the account for a transaction such as cashing the voucher for a player. Additionally, the player may use the voucher in another gaming machine's bill acceptor 410 . When the voucher is cashed by the player, or the voucher is used in another gaming machine's bill acceptor 416 , the voucher account is emptied and deleted by the gaming machine management system.
[0040] [0040]FIG. 5 is a process flow diagram of a validation character string verification process in accordance with the present invention. A printer controller receives 500 a validation character string. The printer controller prints 502 a voucher including the received validation character string. The printer controller does so by using the received validation character string to generate print head control signals. The printer controller transmits the print head control signals to a print head. The print head receives the print head control signals and uses them to print a voucher including the validation character string. The printer controller scans 504 the voucher for a scanned validation character string as the print head is printing the voucher. The printer controller scans the voucher using a voucher scanning device. The voucher scanning device generates voucher scan signals including the scanned validation character string by scanning the voucher as the voucher is being printed. The printer controller receives the voucher scan signals including the scanned validation character string.
[0041] In one embodiment of a validation character string verification process, the printer controller generates a scanned validation character string using the voucher scan signals in an OCR process. In another embodiment of a validation character string verification process, the voucher scan signals include a scanned validation character string generated in an OCR process by the voucher scanning device.
[0042] The printer controller compares the scanned validation character string and the received validation character string to verify 506 the scanned validation character string. If the verification process fails, the printer controller voids 508 the voucher.
[0043] In an embodiment of a validation character string verification process, the printer controller receives the validation character string to be printed from a GMIB. In another embodiment of a validation character string verification process, the printer controller receives the validation character string to be printed from a gaming machine management system.
[0044] Although this invention has been described in certain specific embodiments, many additional modifications and variations would be apparent to those skilled in the art. It is therefore to be understood that this invention may be practiced otherwise than as specifically described. Thus, the present embodiments of the invention should be considered in all respects as illustrative and not restrictive, the scope of the invention to be determined by any claims supported by this application and the claims' equivalents rather than the foregoing description. | 4y
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RELATED APPLICATIONS
The present application is a continuation of and claims the benefit of U.S. patent application Ser. No. 12/140,443 filed Jun. 17, 2008 which claims priority from U.S. Provisional Patent Application No. 61/052,445 filed May 12, 2008 both of which are incorporated herein by reference in their entirety.
FIELD OF INVENTION
The present invention relates generally to improvements in prepaid card packaging, and more particularly to advantageous aspects of paper packaging of prepaid cards.
BACKGROUND OF THE INVENTION
As prepaid cards have become more and more prevalent, techniques for cost effectively packaging such cards in a tamper evident manner are highly desirable. While a wide variety of previous approaches have been tried, many such approaches have failed to provide the right balance of features. For example, a highly secure package may be too hard to open by a legitimate customer after purchase, too expensive or both. A very cost effective package may be too susceptible to fraud.
SUMMARY OF THE INVENTION
To such ends, as well as to address other issues addressed further below, one aspect of the present invention addresses a bi-panel having a fold line with a first panel to one side of the fold line and a second panel to the other side of the fold line, the first panel having an area reserved for a product literature insert on an inside face and the second panel having an area reserved for a card located within a no glue region on an inside face; and a wide glue area between the no glue area and the edges of the second panel.
According to a further aspect of the invention, the fold line may be scored.
According to another aspect, the wide glue area is at least 0.5″ wide and may advantageously be approximately 0.625″ for standard credit card sized gift card.
In another aspect, glue is applied to the wide glue area, the bi-panel is folded about the fold line, and the glue is activated to form a tamper evident seal which is at least 0.5″ wide and preferably is approximately 0.625″ wide for a card which has standard sized credit card size.
In another aspect, the bi-panel is a material having a thickness ranging from 0.006″-0.016″.
According to another aspect, the second panel has a magnetic stripe flap extending from a bottom edge.
In a further aspect, the magnetic stripe flap is folded about a fold line and glued to the back of the second panel. In this arrangement the bi-panel may suitable be 8 point paper and the flap is approximately 0.75″ wide.
According to a further aspect, a bar code or bar codes or a magnetic stripe or both are located on an outside face of either the first or second panel or both.
Another aspect of the invention addresses a method for making a tamper evident card carrier comprising forming a bi-panel having a fold line with a first panel to one side of the fold line and a second panel to the other side of the fold line, the first panel having an area reserved for a product literature insert on an inside face and the second panel having an area reserved for a card located within a no glue region on an inside face; and a wide glue area between the no glue area and the edges of the second panel.
In a further aspect, this method comprises scoring the fold line.
According to another aspect, the method comprises applying glue to the wide glue area which is at least 0.5″ wide and preferably is approximately 0.625″ wide for a standard credit card sized card.
In another aspect, the method comprises gluing a gift card to the area for a card with fugitive glue; and gluing a product literature insert to the area for a product literature insert with fugitive glue.
Another aspect of a method addresses applying glue to the wide glue area; folding the bi-panel about the fold line; and activating the glue to form a tamper evident seal which is at least 5″ wide.
In a further aspect of the method, the bi-panel is a material having a thickness ranging from 0.006″-0.016″.
Another aspect of the method addresses forming a magnetic stripe on a flap extending from a bottom edge of the second panel.
Another aspect of the method comprises folding the flap about a fold line; and gluing the flap to the back of the second panel. Further in this method, the bi-panel may advantageously be 8 point paper and the flap is approximately 0.75″ wide. Additionally the method may further comprise forming a bar code on a magnetic stripe on an outside face of either the first or second panel.
A more complete understanding of the present invention, as well as other features and advantages of the invention, will be apparent from the following detailed description, the accompanying drawings, and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an open card carrier blank utilized to form a gift card carrier in accordance with a first alternative of a first embodiment of the invention;
FIG. 2 shows the back of an assembled card carrier in accordance with a second alternative arrangement;
FIG. 3 shows an assembled card carrier in accordance with a third alternative arrangement;
FIG. 4 shows an open card carrier blank utilized to form a gift card carrier in accordance with a second embodiment of the invention;
FIGS. 5-7 show the inside of an open paper blank utilized to form a gift card carrier in accordance with a third embodiment of the invention; the outside of the blank illustrating the foldover of a magstripe to the outside back; the magstripe folded over and glued to the outside back; and perforations of the outside back and front; respectively, of the third embodiment of the invention;
FIGS. 8A and 8B (collectively FIG. 8 ) show a fourth embodiment of the invention; and
FIGS. 9A and 9B (collectively FIG. 9 ) show a method for making a card carrier in accordance with the present invention.
DETAILED DESCRIPTION
FIG. 1 shows a card carrier blank utilized to form a gift card carrier 100 in accordance with a first embodiment of the present invention. More specifically, FIG. 1 shows a bi-panel arrangement in which a first panel 110 and a second panel 120 are folded about a centerline 130 and glued shut to form a gift card carrier as described in further detail below. Aspects of two additional alternative gift card carriers of the first embodiment are illustrated in FIGS. 2 and 3 , respectively. Illustrative dimensions are included in FIG. 1 for the gift card carrier 100 for use with a gift card which is the size of a standard credit card. A presently preferred material for carrier 100 is 12 point white paper having a nominal thickness of 0.012″. It will be recognized that other dimensions may be suitably employed for cards having other dimensions and that materials other than paper may be suitably employed.
First panel 110 has a rectangular area 112 where a terms and condition pamphlet or other product literature insert 10 may be suitably attached with fugitive glue, for example, which allows the pamphlet or insert to be readily removed by a customer that purchases the gift card upon opening the carrier 100 . First panel 110 also includes a first smaller hangtag cutout 114 .
Second panel 120 has a first rectangular area 122 where a gift card 20 is suitably attached with fugitive glue, for example, allowing the gift card to be readily detached from the carrier once a customer has purchased the gift card and opened the carrier 100 . A second area 124 is a tolerance area within which the gift card may be acceptably mounted. In FIG. 1 , card 20 is shown centered within the tolerance area 124 . A third area 126 defines a no glue region. Third area 126 is larger than the acceptable card placement area 124 so that a no glue buffer surrounds the card 20 . Second panel 120 also includes a second larger hangtag cutout 128 . Additionally, the second panel 120 includes a semicircular slot 129 .
In this embodiment, glue is adhered or otherwise applied around the edges of both panels 110 and 120 . In one approach, the glue is applied everywhere except the glue free zones with a glue applicator as part of the process of printing the card carrier with any text, such as the manufacturer's name or logo, the card company, name, logo and the like, or any other printed text, advertising materials and the like that are desired to be printed on the carrier 100 .
Then, the gift card 20 is attached to the panel 120 , and the pamphlet or product literature insert 10 is attached to panel 110 . The panels are folded together about centerfold line 130 like a clamshell so that the cutouts 114 and 128 form a hangtag opening for hanging the gift card sealed in the carrier 100 for display. Where glue applied during printing is utilized, heat and pressure are applied to activate the glue and to seal the panels 110 and 120 together The seal formed is preferably at least 0.5″ wide and even more preferably is approximately 0.625″ wide which is the case when glue is applied everywhere except the glue free zones. In a second approach, after the booklet and card are attached, hot melt glue is applied to one or both of the panels 110 and 120 in a bead or in dots with a pressure gun applicator. Where hot melt glue is employed, the closed carrier is rolled between rollers as the glue cools and sets so that the glue is applied uniformly and a wide area seal is formed.
In a first alternative of the first embodiment, the exterior of carrier 100 does not include any further external features though it will be recognized that as noted above a wide variety of printed material may be added as desired.
FIG. 2 shows back panel 140 of a second alternative carrier 200 after the panels 110 and 120 have been glued together. In the alternative shown, a barcode 245 is printed on the back panel 240 of the carrier 200 . This barcode 245 may be utilized as an activation reference code. Additional bar codes not shown may be utilized as a sales reference code to be scanned by a bar code scanner in a known manner, for manufacturing tracking purposes, or the like.
When the two panels 110 and 120 have been folded and glued together, it is seen from FIG. 1 that the bottom edge of card 20 is 0.875″ above the bottom edge of carrier 100 . If the bottom edge of card 20 is placed at the bottom of the acceptable card placement area, it is still 0.750″ above the bottom edge of carrier 200 . It is further seen from FIG. 1 that with the approach in which glue is applied during printing, glue can be applied in a relatively wide area 0.625″ wide all around the no glue region 126 . With the application of hotmelt glue a similarly broad swath of glue can surround the no glue region 126 .
As further seen in FIG. 2 , upon assembly of the carrier 100 , slot 129 results in an external opening tab 130 which can be pulled by a purchaser to begin to tear open the carrier 100 to get access to the gift card sealed inside. It also creates a vent which allows internal air to escape upon a change of temperature, pressure or the like without damaging the seal. Finally, it also allows a simple visual confirmation that a card is contained in the carrier 100 . It will be recognized that alternative venting slots may be employed, such as a simple parenthesis shaped arc or arcs, or a diagonal cut or cuts. As a first example, if a shipment of gift cards is being transported by truck to Phoenix on a hot summer day, the high temperature in the truck might cause the internal air to expand. If the package had an airtight seal, that seal or the packaging could be damaged. As a second example, if a gift card in a sealed carrier is purchased and sent by air as a Christmas gift, the change in air pressure as the plane goes from near sea level to altitude would result in expansion of the interior air if the package was perfectly sealed, again possibly damaging the seal or the package.
A third alternative gift card carrier 300 is illustrated in FIG. 3 . In this alternative, the gift card carrier 300 is preferably formed from a blank like that of FIG. 1 ; however, the back surface 340 of the assembled card 300 has a magstripe 345 rather than the barcode 345 shown in FIG. 2 . Although not shown, it will be recognized that a further alternative employs both a barcode or barcodes and a magstripe.
It is presently preferred that the magstripe 345 of carrier 100 be readable by a standard magstripe reader designed for reading the magstripe on a standard credit card. Such a credit card has a nominal thickness of 30 mils or 0.030″. As a result, the rollers of the standard credit card reader are spaced so that a card somewhat thicker or thinner than 0.030 inches can be read, but cards substantially thicker or thinner may be susceptible to jamming or fail to read as a result of the failure of the magnetic stripe to register with the read head.
With card 20 having a nominal thickness of 30 mils and two layers of 12 point paper, the thickness of carrier 100 where the card is sandwiched is approximately 0.054″. However, the bottom 0.750″ at the bottom of carrier 100 where magstripe 345 is found is only approximately 0.024″ thick and can be fed through the rollers of a standard swipe reader.
A further advantage of all three alternative carriers 100 , 200 and 300 of the first embodiment is that the thinness of the 12 point paper stock and the width of the glued area between the card 20 and the edges of carriers makes the resulting carriers highly tamper evident with respect to a type of fraud where someone intent on removing cards without detection takes a razor, knife, or the like and attempts to slit open the carrier on one of its edges. Where a glue is selected so that it is harder to cut or as hard to cut as the paper and the paper is thin so that it does not provide a guide for the cutting edge, one intent on fraud cannot readily cut the carrier open without the tampering being evident by causing visual damage to the carrier.
Aspects of a second embodiment of a card carrier in accordance with the present invention are illustrated in FIG. 4 . In FIG. 4 , a top fold tablet card carrier 400 is illustrated. Similar to the embodiment of FIG. 1 , a first panel 410 includes a first area 412 reserved for a terms and conditions pamphlet or other product literature insert. No literature is shown in FIG. 4 . First panel 410 also includes a first smaller hangtag cutout 414 .
Second panel 420 has a first area 422 reserved for attaching a gift card. No gift card is shown in FIG. 4 . A second area 424 illustrates a larger tolerance area within which the gift card may be acceptably mounted. A third area 426 defines a no glue region. Second panel 420 also includes a second larger hangtag cutout 428 . Additionally, the second panel 420 includes a semicircular slot 429 .
In this second embodiment, glue is applied around the edges of second panel 420 in either of the two ways described above in connection with FIG. 1 . A gift card is attached to the panel 420 . A terms and condition pamphlet or other product literature insert is attached to panel 410 . Glue may be preapplied during printing as discussed above and the panels are then folded together about top fold line 430 . The package is then sealed using a high pressure heat press that activates the glue as discussed above. Alternatively, as also discussed above, hot melt glue may be applied and then after folding the panels together, the card carrier is rolled under pressure rollers to seal the package with a wide seal area. In a first alternative, the carrier 400 has no external barcode or magstripe. In a second alternative, the carrier 400 has a barcode as seen in FIG. 2 and in a third alternative, the carrier 400 has a magstripe as seen in FIG. 3 .
FIG. 5 shows a gift card carrier blank used to form a gift card carrier 500 in accordance with a third embodiment of the present invention. More specifically, FIG. 5 shows a bi-panel arrangement in which a first panel 510 and a second panel 520 are folded about a centerline 530 and glued shut to form a gift card carrier as described in further detail below. Illustrative dimensions are included in FIG. 5 for the gift card carrier 500 for use with a gift card which is the size of a standard credit card. A presently preferred material for carrier 500 is 8 point white paper having a nominal thickness of 0.008″ It will be recognized that other dimensions may be suitably employed for cards having other dimensions.
First panel 510 has a rectangular area 512 where a teens and condition pamphlet or other product literature insert 10 is suitably attached with fugitive glue, for example, which allows the booklet to be readily removed by a customer that purchases the gift card upon opening carrier 500 . First panel 510 also includes a first smaller hangtag cutout 514 . In this embodiment, area 512 is also a no glue area and glue may be applied during printing outside this area or hot melt glue may be applied as discussed above.
Second panel 520 has a first area 522 where a gift card 20 is suitably attached with fugitive glue, for example, allowing the gift card to be readily detached from the carrier. A second area 524 illustrates a tolerance area within which the gift card may be acceptably mounted. A third area 526 defines a no glue region. Third area 526 is larger than the acceptable card placement area 524 so that a no glue buffer surrounds the card 20 . Second panel 520 also includes a second larger hangtag cutout 528 . Additionally, the second panel 520 includes a three quarter inch flap 527 with a half inch magstripe 528 . As discussed further in connection with FIGS. 6 and 7 below, the flap 527 is folded over to the back of carrier 500 and glued to the back of second panel 520 .
FIG. 6 shows back 540 of the carrier 500 with the flap 527 in the process of being folded about fold line 529 . In a presently preferred embodiment, the back of panel 520 also includes a white area 525 for the printing of a barcode or other desired information.
As seen in FIG. 7 , the flap 527 has now been glued to the back of the panel 520 . Since the flap has a thickness of 0.008″ and each panel has a thickness of 0.008″, the total thickness of the finished carrier 500 at the magstripe is 0.024″ so the magstripe can be read by a typical magstripe reader as discussed above.
FIG. 7 further illustrates a number of lines of perforations 531 , 533 , 535 and 537 . In a presently preferred embodiment, these perforations are cut by a disc with 12 teeth per inch. The cuts are 0.0150″ and ties are 0.0075″. The resulting perforations allow the customer purchasing the end product to tear it open after purchase to obtain access to the card 20 and literature 10 . Someone intent on fraud cannot readily open the package without it being tamper evident.
In this third embodiment, after folding and gluing bottom panel 527 to the back panel, glue is applied around the edges of second panels 510 and 520 . In one approach, the glue is applied everywhere except the glue free zones 512 and 526 as part of the process of printing the card carrier with any text, such as the manufacturer's name or logo, the card company, name, logo and the like, or any other printed text, advertising materials and the like that are desired to be printed on the carrier 500 . In a second approach, hot melt glue is applied outside the glue free zones to one or both of the panels 510 and 520 in a bead or in dots with a pressure gun applicator.
Then, the gift card 20 is attached to the panel 520 . The product literature booklet 10 is attached to panel 510 . The panels are folded together about scored centerfold line 530 like a clamshell so that the cutouts 514 and 528 form a hangtag opening for hanging the gift card sealed in its carrier 500 for display. Where printed glue is utilized, heat and pressure are applied to activate the glue and to seal the panels 510 and 520 together. Where hot melt glue is employed, the closed carrier is rolled between rollers as the glue cools and sets.
When the two panels 510 and 520 have been folded and glued together, it is seen from FIG. 8 that the bottom edge of card 20 is more than 0.750″ above the bottom edge of carrier 500 . With the bottom edge of card 20 placed at the bottom of the acceptable card placement area, it is still at least 0.750″ above the bottom edge of carrier 500 . It is further seen from FIG. 7 that with the printed glue approach, glue can be applied in a wide area 0.625″ wide all around the no glue regions 512 and 526 . With the application of hotmelt glue, a similarly broad swath of glue can surround these no glue regions.
Upon purchase of the carrier 500 , the perforations can be torn by a purchaser to tear open the carrier 500 to get access to the gift card sealed inside.
It is presently preferred that the magstripe 528 of carrier 500 be readable by a standard magstripe reader utilized for reading the magstripe on a standard credit card. Such a credit card has a nominal thickness of 30 mils or 0.030″. As a result, the rollers of the standard credit card reader are spaced so that a card somewhat thicker or thinner than 0.030 inches can be read, but cards substantially thicker or thinner may be susceptible to jamming or fail to read as a result of the failure of the magnetic stripe to register with the read head.
With card 20 having a nominal thickness of 30 mils and two layers of 8 point paper, the thickness of carrier 500 where the card is sandwiched is approximately 0.046″. However, the bottom 0.750″ at the bottom of carrier 300 where magstripe 345 is found is 0.024″ thick and can be fed through the rollers of a standard swipe reader.
A further advantage of the carrier 500 is that the thinness of the 8 point paper stock and the width of the glued area between the card 20 and the edges of the carrier makes the resulting carrier highly tamper evident with respect to a type of fraud where someone intent on stealing cards takes a razor, knife, or the like and attempts to slit open the carrier on one of its edges. Where a glue is selected so that it is harder to cut or as hard to cut as the paper and the paper is thin so that it does not provide a guide for the cutting edge, one intent on fraud cannot readily cut the carrier open without the tampering being evident.
While a presently preferred third embodiment is shown, it will be recognized that variations on this embodiment may be readily made by those of skill in the art. For example, with 6 point paper, inside front panel 510 can also have a foldover flap like the magstripe flap 527 but without a magstripe, so that the overall thickness is still 0.024″ a the bottom where the magstripe is to be passed through a magstripe reader. Decorative edging or printing may be applied to the front panel flap so it is aesthetically pleasing to purchasers.
FIGS. 8A and 8B (collectively FIG. 8 ) show a fourth embodiment of a card carrier 800 in accordance with the present invention. In FIG. 8 , a first panel 810 of 24 point white paper and a separate second panel 820 of 24 point white paper are shown. For standard credit card sized gift cards, the dimensions of these two panels will preferably be the same as those shown for panels 110 and 120 in FIG. 1 , respectively. Panel 810 has a first smaller hangtag cutout 814 . Panel 820 has a second larger hangtag cutout 828 . As addressed above, it will be recognized that thinner paper may be employed in place of 24 point white paper and that an overall bottom thickness of 0.048″ will be too thick for reading with a standard magstripe reader with an approximately 30 mil reader head spacing.
First panel 810 has a rectangular area 812 where a terms and conditions pamphlet or other product literature insert 10 may be suitably attached with fugitive glue, for example, which allows the booklet to be readily removed by a customer that purchases the gift card upon opening carrier 800 . Second panel 820 has a first area 822 where gift card 20 is suitably attached with fugitive glue. In this fourth embodiment glue is adhered round the edges of either of the two panels 810 and 820 . The two panels are aligned together and the glue is activated as discussed above.
FIGS. 9A and 9B (collectively FIG. 9 ) illustrate aspects of a method 900 of making a tamper evident card in accordance with the present invention. In step 902 , a bi-panel is formed having a fold line with a first panel to one side of the fold line, the first panel having an area reserved for a product literature insert on an inside face and the second panel having an area reserved for a card located within a no glue region on an inside face. A wide glue area between the no glue area and the edges of the second panel is also established.
In step 904 , the fold line is scored. In step 906 , glue is applied to the wide glue area. The wide glue area is preferably at least 0.5″ wide and for a standard credit card sized card may advantageously be 0.625″ wide.
In step 908 , a gift card is glued to the area for a card with fugitive glue. In step 910 , a product literature insert is glued to the area for a product literature insert with fugitive glue.
In step 912 , the bi-panel is folded about the fold line. In step 914 , the glue is activated to form a tamper evident seal which is at least 0.5″ wide.
In an optional step 916 , a magnetic stripe is formed on a flap extending from a bottom edge of the second panel. In an optional step 918 , the flap is folded about a fold line and glued to the back of the second panel.
In a further optional step 920 , a bar code or a magnetic stripe or both are formed on an outside face of either the first or second panel.
While the present invention has been disclosed in the context of various aspects of presently preferred embodiments, it will be recognized that the invention may be suitably varied and applied to other environments consistent with the teachings above and the claims which follow. By way of example, while the present invention is described in connection with embodiments for standard credit card sized cards, it will be recognized that the present teachings may be adapted to other shapes and sizes of cards, such as key fob or key chain cards, smart cards, and the like. Further, while the present invention is described in connection with embodiments in which paper is employed, it will be recognized that various other types of materials, such as plastics and the like, may be suitably employed so long as that material can be cut, folded and adhered consistent with the teachings herein. Additionally, while presently preferred approaches to gluing panels together have been described, variations thereon will be readily adapted to the demands of a particular environment or context. | 4y
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of co-pending U.S. application Ser. No. 09/565,864, filed May 5, 2000, now U.S. Patent ______, issued ______, which itself is a divisional application of co-pending U.S. application Ser. No. 08/747,863, filed Nov. 13, 1996, now U.S. Pat. No. 6,197,310 , issued Mar. 6, 2001, which itself is a divisional of U.S. patent application Ser. No. 08/157,005, filed Nov. 26, 1993, now U.S. Pat. No. 5,620,691, which is a U.S. National Stage under 35 U.S.C. § 371 of International Patent Application PCT/NL92/00096, filed Jun. 5, 1992, the contents of all of which are incorporated by this reference.
TECHNICAL FIELD
[0002] The invention relates to the isolation, characterization and utilization of the causative agent of the Mystery Swine Disease (MSD). The invention utilizes the discovery of the agent causing the disease and the determination of its genome organization, the genomic nucleotide sequence and the proteins encoded by the genome, for providing protection against and diagnosis of infections, in particular, protection against and diagnosis of MSD infections, and for providing vaccine compositions and diagnostic kits, either for use with MSD or with other pathogen-caused diseases.
BACKGROUND
[0003] In the winter and early spring of 1991, the Dutch pig industry was struck by a sudden outbreak of a new disease among breeding sows. Most sows showed anorexia, some aborted late in gestation (around day 110), showed stillbirths or gave birth to mummified fetuses and some had fever. Occasionally, sows with bluish ears were found, therefore, the disease was commonly named “Abortus Blauw”. The disease in the sows was often accompanied by respiratory distress and death of their young piglets and often by respiratory disease and growth retardation of older piglets and fattening pigs.
[0004] The cause of this epizootic was not known, but the symptoms resembled those of a similar disease occurring in Germany since late 1990, and resembled those of the so-called “Mystery Swine Disease” as seen since 1987 in the mid-west of the United States of America and in Canada (Hill, 1990). Various other names have been used for the disease; in Germany it is known as “Seuchenhafter Spätabort der Schweine” and in North America it is also known as “Mystery Pig Disease”, “Mysterious Reproductive Syndrome”, and “Swine Infertility and Respiratory Syndrome”. In North America, Loula (1990) described the general clinical signs as:
[0005] 1) off feed, sick animals of all ages;
[0006] 2) abortions, stillbirths, weak pigs, mummies;
[0007] 3) post-farrowing respiratory problems; and
[0008] 4) breeding problems.
[0009] No causative agent has as yet been identified, but encephalomyocarditis virus (“EMCV”), porcine parvo virus (“PPV”), pseudorabies virus (“PRV”), swine influenza virus (“SIV”), bovine viral diarrhea virus (“BVDV”), hog cholera virus (“HCV”), porcine entero viruses (“PEV”), an influenza-like virus, chlamidiae, leptospirae, have all been named as a possible cause (Loula, 1990; Mengeling and Lager, 1990; among others).
SUMMARY OF THE INVENTION
[0010] The invention provides a composition of matter comprising isolated Lelystad Agent which is the causative agent of Mystery Swine Disease, the Lelystad Agent essentially corresponding to the isolate Lelystad Agent (CDI-NL-2.91) deposited Jun. 5, 1991 with the Institut Pasteur, Collection Nationale de Cultures De Microorganismes (C.N.C.M.) 25, rue du Docteur Roux, 75724 -Paris Cedex 15, France, deposit number I-1102. The words “essentially corresponding” refer to variations that occur in nature and to artificial variations of Lelystad Agent, particularly those which still allow detection by techniques like hybridization, PCR and ELISA, using Lelystad Agent-specific materials, such as Lelystad Agent-specific DNA or antibodies.
[0011] The composition of matter may comprise live, killed, or attenuated isolated Lelystad Agent; a recombinant vector derived from Lelystad Agent; an isolated part or component of Lelystad Agent; isolated or synthetic protein (poly)peptide, or nucleic acid derived from Lelystad Agent; recombinant nucleic acid which comprises a nucleotide sequence derived from the genome of Lelystad Agent; a (poly)peptide having an amino acid sequence derived from a protein of Lelystad Agent, the (poly)peptide being produced by a cell capable of producing it due to genetic engineering with appropriate recombinant DNA; an isolated or synthetic antibody which specifically recognizes a part or component of Lelystad Agent; or a recombinant vector which contains nucleic acid comprising a nucleotide sequence coding for a protein or antigenic peptide derived from Lelystad Agent.
[0012] On the DNA level, the invention specifically provides a recombinant nucleic acid, more specifically recombinant DNA, which comprises a Lelystad Agent-specific nucleotide sequence shown in FIG. 1 (SEQ ID NO: 1) which includes FIGS. 1 a ; through 1 q . Preferably, the Lelystad Agent-specific nucleotide sequence is selected from any one of the ORFs (Open Reading Frames) shown in FIG. 1 (SEQ ID NO: 1).
[0013] On the peptide/protein level, the invention specifically provides a peptide comprising a Lelystad Agent-specific amino acid sequence shown in FIG. 1 (SEQ ID NO: 1).
[0014] The invention further provides a vaccine composition for vaccinating animals, in particular mammals, more in particular pigs or swine, to protect them against Mystery Swine Disease, comprising Lelystad Agent, either live, killed, or attenuated; or a recombinant vector which contains nucleic acid comprising a nucleotide sequence coding for a protein or antigenic peptide derived from Lelystad Agent; an antigenic part or component of Lelystad Agent; a protein or antigenic polypeptide derived from, or a peptide mimicking an antigenic component of, Lelystad Agent; and a suitable carrier or adjuvant.
[0015] The invention also provides a vaccine composition for vaccinating animals, in particular mammals, more in particular pigs or swine, to protect them against a disease caused by a pathogen, comprising a recombinant vector derived from Lelystad Agent, the nucleic acid of the recombinant vector comprising a nucleotide sequence coding for a protein or antigenic peptide derived from the pathogen, and a suitable carrier or adjuvant.
[0016] The invention further provides a diagnostic kit for detecting nucleic acid from Lelystad Agent in a sample, in particular a biological sample such as blood or blood serum, sputum, saliva, or tissue, derived from an animal, in particular a mammal, more in particular a pig or swine, comprising a nucleic acid probe or primer which comprises a nucleotide sequence derived from the genome of Lelystad Agent, and suitable detection means of a nucleic acid detection assay.
[0017] The invention also provides a diagnostic kit for detecting antigen from Lelystad Agent in a sample, in particular a biological sample such as blood or blood serum, sputum, saliva, or tissue, derived from an animal, in particular a mammal, more in particular a pig or swine, comprising an antibody which specifically recognizes a part or component of Lelystad Agent, and suitable detection means of an antigen detection assay.
[0018] The invention also provides a diagnostic kit for detecting an antibody which specifically recognizes Lelystad Agent in a sample, in particular a biological sample such as blood or blood serum, sputum, saliva, or tissue, derived from an animal, in particular a mammal, more in particular a pig or swine, comprising Lelystad Agent; an antigenic part or component of Lelystad Agent; a protein or antigenic polypeptide derived from Lelystad Agent; or a peptide mimicking an antigenic component of Lelystad Agent; and suitable detection means of an antibody detection assay.
[0019] The invention also relates to a process for diagnosing whether an animal, in particular a mammal, more in particular a pig or swine, is contaminated with the causative agent of Mystery Swine Disease, comprising preparing a sample, in particular a biological sample such as blood or blood serum, sputum, saliva, or tissue, derived from the animal, and examining whether it contains Lelystad Agent nucleic acid, Lelystad Agent antigen, or antibody specifically recognizing Lelystad Agent, the Lelystad Agent being the causative agent of Mystery Swine Disease and essentially corresponding to the isolate Lelystad Agent (CDI-NL-2.91) deposited Jun. 5, 1991 with the Institut Pasteur, Paris, France, deposit number I-1102.
DETAILED DESCRIPTION OF THE INVENTION
[0020] The invention is a result of combined efforts of the Central Veterinary Institute (CVI) and the Regional Animal Health Services (RAHS) in the Netherlands in trying to find the cause of the new disease MSD. Farms with pigs affected by the new disease were visited by field veterinarians of the RAHS. Sick pigs, specimens of sick pigs, and sow sera taken at the time of the acute and convalescent phase of the disease were sent for virus isolation to the RAHS and the CVI. Paired sera of affected sows were tested for antibodies against ten known pig-viruses. Three different viruses, encephalomyocarditis virus, porcine entero virus type 2, porcine entero virus type 7, and an unknown agent, Lelystad Agent (LA), were isolated. Sows which had reportedly been struck with the disease mainly seroconverted to LA, and rarely to any of the other virus isolates or the known viral pathogens. In order to reproduce MSD experimentally, eight pregnant sows were inoculated intranasally with LA at day 84 of gestation. One sow gave birth to seven dead and four live but very weak piglets at day 109 of gestation; the four live piglets died one day after birth. Another sow gave birth at day 116 to three mummified fetuses, six dead piglets and three live piglets; two of the live piglets died within one day. A third sow gave birth at day 117 to two mummified fetuses, eight dead and seven live piglets. The other sows farrowed around day 115 and had less severe reproductive losses. The mean number of live piglets from all eight sows at birth was 7.3 and the mean number of dead piglets at birth was 4.6. Antibodies directed against LA were detected in 10 out of 42 serum samples collected before the pigs had sucked. LA was isolated from three piglets that died shortly after birth. These results justify the conclusion that LA is the causal agent of mystery swine disease.
[0021] LA grows with a cytopathic affect in pig lung macrophages and can be identified by staining in an immuno-peroxidase-monolayer assay (IPMA) with post-infection sera of pigs c 829 and b 822, or with any of the other post-infection sera of the SPF pigs listed in table 5. Antibodies to LA can be identified by indirect staining procedures in IPMA. LA did not grow in any other cell system tested. LA was not neutralized by homologous sera, or by sera directed against a set of known viruses (Table 3). LA did not haemagglutinate with the red blood cells tested. LA is smaller then 200 nm since it passes through a filter with pores of this size. LA is sensitive to chloroform. The above results show that Lelystad Agent is not yet identified as belonging to a certain virus group or other microbiological species. It has been deposited Jun. 5, 1991 under number I-1102 at Institute Pasteur, France.
[0022] The genome organization, nucleotide sequences, and polypeptides derived therefrom, of LA have now been found. These data together with those of others (see below) justify classification of LA (hereafter also called Lelystad Virus or LV) as a member of a new virus family, the Arteriviridae. As prototype virus of this new family we propose Equine Arteritis Virus (EAV), the first member of the new family of which data regarding the replication strategy of the genome and genome organization became available (de Vries et al., 1990, and references therein). On the basis of a comparison of our sequence data with those available for Lactate Dehydrogenase-Elevating Virus (LDV; Godeny et al., 1990), we propose that LDV is also a member of the Arteriviridae.
[0023] Given the genome organization and translation strategy of Arteriviridae, it seems appropriate to place this new virus family into the superfamily of coronaviruses (Snijder et al., 1990a).
[0024] Arteriviruses have in common that their primary target cells in respective hosts are macrophages. Replication of LDV has been shown to be restricted to macrophages in its host, the mouse; whereas this strict propensity for macrophages has not been resolved yet for EAV and LV.
[0025] Arteriviruses are spherical enveloped particles having a diameter of 45-60 nm and containing an icosahedral nucleocapsid (Brinton-Darnell and Plagemann, 1975; Horzinek et al., 1971; Hyllseth, 1973).
[0026] The genome of Arteriviridae consists of a positive stranded polyadenylated RNA molecule with a size of about 12-13 kilobases (kb) (Brinton-Darnell and Plageman, 1975; van der Zeijst et al., 1975). EAV replicates via a 3′ nested set of six subgenomic mRNAs, ranging in size from 0.8 to 3.6 kb, which are composed of a leader sequence, derived from the 5′ end of the genomic RNA, which is joined to the 3′ terminal body sequences (de Vries et al., 1990).
[0027] Here we show that the genome organization and replication strategy of LV is similar to that of EAV, coronaviruses and toroviruses, whereas the genome sizes of the latter viruses are completely different from those of LV and EAV.
[0028] The genome of LV consists of a genomic RNA molecule of about 14.5 to 15.5 kb in length (estimated on a neutral agarose gel), which replicates via a 3′ nested set of subgenomic RNAs. The subgenomic RNAs consist of a leader sequence, the length of which is yet unknown, which is derived from the 5′ end of the genomic RNA and which is fused to the body sequences derived from the 3′ end of the genomic RNA (FIG. 2).
[0029] The nucleotide sequence of the genomic RNA of LV was determined from overlapping cDNA clones. A consecutive sequence of 15,088 bp was obtained covering nearly the complete genome of LV (FIG. 1, SEQ ID NO: 1). In this sequence 8 open reading frames (ORFs) were identified: ORF 1A, ORF 1B, and ORFs 2 to 7.
[0030] ORF 1A and ORF 1B are predicted to encode the viral replicase or polymerase (SEQ ID NO: 2 and SEQ ID NO: 3), whereas ORFs 2 to 6 are predicted to encode structural viral membrane (envelope) associated proteins (SEQ ID NOS: 4-8). ORF 7 is predicted to encode the structural viral nucleocapsid protein (SEQ ID NO: 9).
[0031] Because the products of ORF 6 and ORF 7 of LV (SEQ ID NO: 8 and SEQ ID NO: 9) show a significant similarity with VpX and Vp1 of LDV, respectively, it is predicted that the sequences of ORFs 6 and 7 will also be highly conserved among antigenic variants of LV.
[0032] The complete nucleotide sequence of FIG. 1 (SEQ ID NO: 1) and all the sequences and protein products encoded by ORFs 1 to 7 (SEQ ID NOS: 1-9) and possible other ORFs located in the sequence of FIG. 1 (SEQ ID NO: 1) are especially suited for vaccine development, in whatever sense, and for the development of diagnostic tools, in whatever sense. All possible modes are well known to persons skilled in the art.
[0033] Since it is now possible to unambiguously identify LA, the causal agent of MSD, it can now be tested whether pigs are infected with LA or not. Such diagnostic tests have, until now, been unavailable.
[0034] The test can be performed by virus isolation in macrophages, or other cell culture systems in which LA might grow, and staining the infected cultures with antibodies directed against LA (such as post-infection sera c 829 or b 822), but it is also feasible to develop and employ other types of diagnostic tests.
[0035] For instance, it is possible to use direct or indirect immunohistological staining techniques, i.e., with antibodies directed to LA that are labeled with fluorescent compounds such as isothiocyanate, or labeled with enzymes such as horseradish peroxidase. These techniques can be used to detect LA antigen in tissue sections or other samples from pigs suspected to have MSD. The antibodies needed for these tests can be c 829 or b 822 or other polyclonal antibodies directed against LA, but monoclonal antibodies directed against LA can also be used.
[0036] Furthermore, since the nature and organization of the genome of LA and the nucleotide sequence of this genome have been determined, LA-specific nucleotide sequences can be identified and used to develop oligonucleotide sequences that can be used as probes or primers in diagnostic techniques such as hybridization, polymerase chain reaction, or any other techniques that are developed to specifically detect nucleotide acid sequences.
[0037] It is also possible to test for antibodies directed against LA. Table 5 shows that experimentally infected pigs rapidly develop antibodies against LA, and table 4 shows that pigs in the field also have strong antibody responses against LA. Thus, it can now also be determined whether pigs have been infected with LA in the past. Such testing is of utmost importance in determining whether pigs or pig herds or pig populations or pigs in whole regions or countries are free of LA. The test can be done by using the IPMA as described, but it is also feasible to develop and employ other types of diagnostic tests for the detection of antibodies directed against LA.
[0038] LA-specific proteins, polypeptides, and peptides, or peptide sequences mimicking antigenic components of LA, can be used in such tests. Such proteins can be derived from the LA itself, but it is also possible to make such proteins by recombinant DNA or peptide synthesis techniques. These tests can use specific polyclonal and/or monoclonal antibodies directed against LA or specific components of LA, and/or use cell systems infected with LA or cell systems expressing LA antigen. The antibodies can be used, for example, as a means for immobilizing the LA antigen (a solid surface is coated with the antibody whereafter the LA antigen is bound by the antibody) which leads to a higher specificity of the test, or can be used in a competitive assay (labeled antibody and unknown antibody in the sample compete for available LA antigen).
[0039] Furthermore, the above described diagnostic possibilities can be applied to test whether other animals, such as mammals, birds, insects or fish, or plants, or other living creatures, can be, or are, or have been infected with LA or related agents.
[0040] Since LA has now been identified as the causal agent of MSD, it is possible to make a vaccine to protect pigs against this disease. Such a vaccine can simply be made by growing LA in pig lung macrophage cultures, or in other cell systems in which LA grows. LA can then be purified or not, and killed by established techniques, such as inactivation with formaline or ultra-violet light. The inactivated LA can then be combined with adjuvantia, such as Freund's adjuvans or aluminum hydroxide or others, and this composition can then be injected in pigs.
[0041] Dead vaccines can also be made with LA protein preparations derived from LA infected cultures, or derived from cell systems expressing specifically LA protein through DNA recombinant techniques. Such subunits of LA would then be treated as above, and this would result in a subunit vaccine.
[0042] Vaccines using even smaller components of LA, such as polypeptides, peptides, or peptides mimicking antigenic components of LA, are also feasible for use as dead vaccine.
[0043] Dead vaccines against MSD can also be made by recombinant DNA techniques through which the genome of LA, or parts thereof, is incorporated in vector systems such as vaccinia virus, herpesvirus, pseudorabies virus, adeno virus, baculo virus or other suitable vector systems that can so express LA antigen in appropriate cells systems. LA antigen from these systems can then be used to develop a vaccine as above, and pigs, vaccinated with such products would develop protective immune responses against LA.
[0044] Vaccines against MSD can also be based on live preparations of LA. Since only young piglets and pregnant sows seem to be seriously affected by infection with LA, it is possible to use unattenuated LA, grown in pig lung macrophages, as vaccine for older piglets, or breeding gilts. In this way, sows can be protected against MSD before they get pregnant, which results in protection against abortions and stillbirth, and against congenital infections of piglets. Also the maternal antibody that these vaccinated sows give to their offspring would protect their offspring against the disease.
[0045] Attenuated vaccines (modified-live-vaccines) against MSD can be made by serially passaging LA in pig lung macrophages, in lung macrophages of other species, or in other cell systems, or in other animals, such as rabbits, until it has lost its pathogenicity.
[0046] Live vaccines against MSD can also be made by recombinant DNA techniques through which the genome of LA, or parts thereof, is incorporated in vector systems such as vaccinia virus, herpesvirus, pseudorabies virus, adeno virus or other suitable vector systems that can so express LA antigen. Pigs vaccinated with such live vector systems would then develop protective immune responses against LA.
[0047] Lelystad Agent itself would be specifically suited to use as a live vector system. Foreign genes could be inserted in the genome of LA and could be expressing the corresponding protein during the infection of the macrophages. This cell, which is an antigen-presenting cell, would process the foreign antigen and present it to B-lymphocytes and T-lymphocytes which will respond with the appropriate immune response.
[0048] Since LA seems to be very cell specific and possibly also very species specific, this vector system might be a very safe system, which does not harm other cells or species.
BRIEF DESCRIPTION OF THE DRAWINGS
[0049] [0049]FIG. 1 (SEQ ID NO: 1) shows the nucleotide sequence of the LV genome. The deduced amino acid sequence of the identified ORFs (SEQ ID NOS: 2-9) are shown. The methionines encoded by the (putative) ATG start sites are indicated in bold and putative N-glycosylation sites are underlined. Differences in the nucleotide and amino acid sequence, as identified by sequencing different cDNA clones, are shown. The nucleotide sequence of primer 25, which has been used in hybridization experiments (see FIG. 2 and section “results”), is underlined.
[0050] [0050]FIG. 2 shows the organization of the LV genome. The cDNA clones, which have been used for the determination of the nucleotide sequence, are indicated in the upper part of the figure. The parts of the clones, which were sequenced, are indicated in black. In the lower part of the FIG. the ORFs, identified in the nucleotide sequence, and the subgenomic set of mRNAs, encoding these ORFs are shown. The dashed lines in the ORFs represent alternative initiation sites (ATGs) of these ORFs. The leader sequence of the genomic and subgenomic RNAs is indicated by a solid box.
[0051] [0051]FIG. 3 shows the growth characteristics of LA:
[0052] empty squares—titre of cell-free virus;
[0053] solid squares—titre of cell-associated virus;
[0054] solid line—percentage cytopathic effect (CPE).
MATERIALS AND METHODS
[0055] Sample Collection
[0056] Samples and pigs were collected from farms where a herd epizootic of MSD seemed to occur. Important criteria for selecting the farm as being affected with MSD were: sows that were off feed, the occurrence of stillbirth and abortion, weak offspring, respiratory disease and death among young piglets. Samples from four groups of pigs have been investigated:
[0057] (1) tissue samples and an oral swab from affected piglets from the field (Table 1A);
[0058] (2) blood samples and oral swabs from affected sows in the field (Tables 1B and 4);
[0059] (3) tissue samples, nasal swabs and blood samples collected from specific-pathogen-free (SPF) pigs experimentally infected by contact with affected sows from the field; or
[0060] (4) tissue samples, nasal swabs and blood samples collected from specific-pathogen-free (SPF) pigs experimentally infected by inoculation with blood samples of affected sows from the field (Tables 2 and 5).
[0061] Sample Preparation
[0062] Samples for virus isolation were obtained from piglets and sows which on clinical grounds were suspected to have MSD, and from experimentally infected SPF pigs, sows and their piglets.
[0063] Tissue samples were cut on a cryostat microtome and sections were submitted for direct immunofluorescence testing (IFT) with conjugates directed against various pig pathogens.
[0064] 10% Suspensions of tissues samples were prepared in Hank's BSS supplemented with antibiotics, and oral and nasal swabs were soaked in Hank's BSS supplemented with antibiotics. After one hour at room temperature, the suspensions were clarified for 10 min at 6000 g and the supernatant was stored at −70° C. for further use. Leucocyte fractions were isolated from EDTA or heparin blood as described earlier (Wensvoort and Terpstra, 1988) and stored at −70° C. Plasma and serum for virus isolation were stored at −70° C.
[0065] Serum for serology was obtained from sows suspected to be in the acute phase of MSD, a paired serum was taken 3-9 weeks later. Furthermore, sera were taken from the experimentally infected SPF pigs at regular intervals and colostrum and serum was taken from experimentally infected sows and their piglets. Sera for serology were stored at −20° C.
[0066] Cells
[0067] Pig lung macrophages were obtained from lungs of 5-6 weeks old SPF pigs or from lungs of adult SPF sows from the Central Veterinary Institute's own herd. The lungs were washed five to eight times with phosphate buffered saline (PBS). Each aliquot of washing fluid was collected and centrifuged for 10 min at 300 g. The resulting cell pellet was washed again in PBS and resuspended in cell culture medium (160 ml medium 199, supplemented with 20 ml 2.95% tryptose phosphate, 20 ml fetal bovine serum (FBS), and 4.5 ml 1.4% sodium bicarbonate) to a concentration of 4×10 7 cells/ml. The cell suspension was then slowly mixed with an equal volume of DMSO mix (6.7 ml of above medium, 1.3 ml FBS, 2 ml dimethylsulfoxide 97%), aliquoted in 2 ml ampoules and stored in liquid nitrogen.
[0068] Macrophages from one ampoule were prepared for cell culture by washing twice in Earle's MEM, and resuspended in 30 ml growth medium (Earle's MEM, supplemented with 10% FBS, 200 U/ml penicillin, 0.2 mg/ml streptomycine, 100 U/ml mycostatin, and 0.3 mg/ml glutamine). PK-15 cells (American Type Culture Collection, CCL33) and SK-6 cells (Kasza et al., 1972) were grown as described by Wensvoort et al. (1989). Secondary porcine kidney (PK2) cells were grown in Earle's MEM, supplemented with 10% FBS and the above antibiotics. All cells were grown in a cell culture cabinet at 37° C. and 5% CO 2 .
[0069] Virus Isolation Procedures
[0070] Virus isolation was performed according to established techniques using PK2, PK-15 and SK-6 cells, and pig lung macrophages. The former three cells were grown in 25 ml flasks (Greiner), and inoculated with the test sample when monolayers had reached 70-80% confluency. Macrophages were seeded in 100 μl aliquots in 96-well microtiter plates (Greiner) or in larger volumes in appropriate flasks, and inoculated with the test sample within one hour after seeding. The cultures were observed daily for cytopathic effects (CPE), and frozen at −70° C. when 50-70% CPE was reached or after five to ten days of culture. Further passages were made with freeze-thawed material of passage level 1 and 2 or higher. Some samples were also inoculated into nine to twelve day old embryonated hen eggs. Allantoic fluid was subinoculated two times using an incubation interval of three days and the harvest of the third passage was examined by haemagglutination at 4° C. using chicken red blood cells, and by an ELISA specifically detecting nucleoprotein of influenza A viruses (De Boer et al., 1990).
[0071] Serology
[0072] Sera were tested in haemagglutinating inhibition tests (HAI) to study the development of antibody against haemagglutinating encephalitis virus (HEV), and swine influenza viruses H1N1 and H3N2 according to the protocol of Masurel (1976). Starting dilutions of the sera in HAI were 1:9, after which the sera were diluted twofold.
[0073] Sera were tested in established enzyme-linked immuno-sorbent assays (ELISA) for antibodies against the glycoprotein gI of pseudorabies virus (PRV; Van Oirschot et al., 1988), porcine parvo virus (PPV; Westenbrink et al., 1989), bovine viral diarrhea virus (BVDV; Westenbrink et al., 1986), and hog cholera virus (HCV; Wensvoort et al., 1988). Starting dilutions in the ELISA's were 1:5, after which the sera were diluted twofold.
[0074] Sera were tested for neutralizing antibodies against 30-300 TCID 50 of encephalomyocarditis viruses (EMCV), porcine enteroviruses (PEV), and Lelystad Agent (LA) according to the protocol of Terpstra (1978). Starting dilutions of the sera in the serum neutralization tests (SNT) were 1:5, after which the sera were diluted twofold.
[0075] Sera were tested for binding with LA in an immuno-peroxidase-monolayer assay (IPMA). Lelystad Agent (LA; code: CDI-NL-2.91) was seeded in microtiter plates by adding 50 ml growth medium containing 100 TCID 50 LA to the wells of a microtiter plate containing freshly seeded lung macrophages. The cells were grown for two days and then fixed as described (Wensvoort, 1986). The test sera were diluted 1:10 in 0.15 M NaCl, 0.05% Tween 80, 4% horse serum, or diluted further in fourfold steps, added to the wells and then incubated for one hour at 37° C. Sheep-anti-pig immunoglobulins (Ig) conjugated to horse radish peroxidase (HRPO, DAKO) were diluted in the same buffer and used in a second incubation for one hour at 37° C., after which the plates were stained as described (Wensvoort et al., 1986). An intense red staining of the cytoplasm of infected macrophages indicated binding of the sera to LA.
[0076] Virus Identification Procedures
[0077] The identity of cytopathic isolates was studied by determining the buoyant density in CsCl, by estimating particle. size in negatively stained preparations through electron microscopy, by determining the sensitivity of the isolate to chloroform and by neutralizing the CPE of the isolate with sera with known specificity (Table 3). Whenever an isolate was specifically neutralized by a serum directed against a known virus, the isolate was considered to be a representative of this known virus.
[0078] Isolates that showed CPE on macrophage cultures were also studied by staining in IPMA with post-infection sera of pigs c 829 or b 822. The isolates were reinoculated on macrophage cultures and fixed at day 2 after inoculation before the isolate showed CPE. Whenever an isolate showed reactivity in IPMA with the post-infection sera of pigs c 829 or b 822, the isolate was considered to be a representative of the Lelystad Agent. Representatives of the other isolates grown in macrophages or uninfected macrophages were also stained with these sera to check the specificity of the sera.
[0079] Further Identification of Lelystad Agent
[0080] Lelystad Agent was further studied by haemagglutination at 4° C. and 37° C. with chicken, guinea pig, pig, sheep, or human O red blood cells. SIV, subtype H3N2, was used as positive control in the haemagglutination studies.
[0081] The binding of pig antisera specifically directed against pseudorabies virus (PRV), transmissible gastroenteritis virus (TGE), porcine epidemic diarrhea virus (PED), haemagglutinating encephalitis virus (HEV), African swine fever virus (ASFV), hog cholera virus (HCV) and swine influenza virus (SIV) type H1N1 and H3N2, of bovine antisera specifically directed against bovine herpes viruses type 1 and 4 (BHV 1 and 4), malignant catarrhal fever (MCF), parainfluenza virus 3 (PI3), bovine respiratory syncitial virus (BRSV) and bovine leukemia virus (BLV), and of avian antisera specifically directed against avian leukemia virus (ALV) and infectious bronchitis virus (IBV) was studied with species-Ig-specific HRPO conjugates in an IPMA on LA infected and uninfected pig lung macrophages as described above.
[0082] We also tested in IPMA antisera of various species directed against mumps virus, Sendai virus, canine distemper virus, rinderpest virus, measles virus, pneumonia virus of mice, bovine respiratory syncytial virus, rabies virus, foamy virus, maedi-visna virus, bovine and murine leukemia virus, human, feline and simian immunodeficiency virus, lymphocytic choriomeningitis virus, feline infectious peritonitis virus, mouse hepatitis virus, Breda virus, Hantaan virus, Nairobi sheep disease virus, Eastern, Western and Venezuelan equine encephalomyelitis virus, rubellavirus, equine arteritis virus, lactic dehydrogenase virus, yellow fever virus, tick-born encephalitis virus and hepatitis C virus.
[0083] LA was blindly passaged in PK2, PK- 15, and SK-6 cells, and in embryonated hen eggs. After two passages, the material was inoculated again into pig lung macrophage cultures for reisolation of LA.
[0084] LA was titrated in pig lung macrophages prior to and after passing through a 0.2 micron filter (Schleicher and Schuell). The LA was detected in IPMA and by its CPE. Titres were calculated according to Reed and Muench (1938).
[0085] We further prepared pig antisera directed against LA. Two SPF pigs (21 and 23) were infected intranasally with 10 5 TCID 50 of a fifth cell culture passage of LA. Two other SPF pigs (25 and 29) were infected intranasally with a fresh suspension of the lungs of an LA-infected SPF piglet containing 10 5 TCID 50 LA. Blood samples were taken at 0, 14, 28, and 42 days post-infection (dpi).
[0086] We further grew LA in porcine alveolar macrophages to determine its growth pattern over time. Porcine alveolar macrophages were seeded in F25 flasks (Greiner), infected with LA with a multiplicity of infection of 0.01 TCID 50 per cell. At 8, 16,24, 32,40,48, 56, and 64 h after infection, one flask was examined and the percentage of CPE in relation to a noninfected control culture was determined. The culture medium was then harvested and replaced with an equal volume of phosphate-buffered saline. The medium and the flask were stored at −70° C. After all cultures had been harvested, the LA titres were determined and expressed as log TCID 50 ml −1 .
[0087] The morphology of LA was studied by electronmicroscopy. LA was cultured as above. After 48 h, the cultures were freeze-thawed and centrifuged for 10 min at 6000.times.g. An amount of 30 ml supernatant was then mixed with 0.3 ml LA-specific pig serum and incubated for 1.5 h at 37° C. After centrifugation for 30 min at 125,000× g, the resulting pellet was suspended in 1% Seakem agarose ME in phosphate-buffered saline at 40° C. After coagulation, the agarose block was immersed in 0.8% glutaraldehyde and 0.8% osmiumtetroxide (Hirsch et al., 1968) in veronal/acetate buffer, pH 7.4 (230 mOsm/kg H 2 O), and fixed by microwave irradiation. This procedure was repeated once with fresh fixative. The sample was washed with water, immersed in 1% uranyl acetate, and stained by microwave irradiation. Throughout all steps, the sample was kept at 0° C. and the microwave (Samsung RE211D) was set at defrost for 5 min. Thin sections were prepared with standard techniques, stained with lead citrate (Venable et al., 1965), and examined in a Philips CM 10 electron microscope.
[0088] We further continued isolating LA from sera of pigs originating from cases of MSD. Serum samples originated from the Netherlands (field case the Netherlands 2), Germany (field cases Germany 1 and Germany 2; courtesy Drs. Berner, Müinchen and Nienhoff, Münster), and the United States [experimental case United States 1 (experiment performed with ATCC VR-2332; courtesy Drs. Collins, St. Paul and Chladek, St. Joseph), and field cases United States 2 and United States 3; courtesy Drs. van Alstine, West Lafayette and Slife, Galesburg]. All samples were sent to the “Centraal Diergeneeskundig Instituut, Lelystad” for LA diagnosis. All samples were used for virus isolation on porcine alveolar macrophages as described. Cytophatic isolates were passaged three times and identified as LA by specific immunostaining with anti-LA post infection sera b 822 and c 829.
[0089] We also studied the antigenic relationships of isolates NL1 (the first LA isolate; code CDI-NL-2.91), NL2, GE1, GE2, US1, US2, and US3. The isolates were grown in macrophages as above and were tested in IPMA with a set of field sera and two sets of experimental sera. The sera were also tested in IPMA with uninfected macrophages.
[0090] The field sera were: Two sera positive for LV (TH-187 and TO-36) were selected from a set of LA-positive Dutch field sera. Twenty-two sera were selected from field sera sent from abroad to Lelystad for serological diagnosis. The sera originated from Germany (BE-352, BE-392 and NI-f2; courtesy Dr. Bemer, München and Dr. Nienhoff, Münster), the United Kingdom (PA-141615, PA-141617 and PA-142440; courtesy Dr. Paton, Weybridge), Belgium (PE-1960; courtesy Prof. Pensaert, Gent), France (EA-2975 and EA-2985; courtesy Dr. Albina, Ploufragan), the United States (SL-441, SL-451, AL-RP9577, AL-P10814/33, AL-4994A, AL-7525, JC-MN41, JC-MN44 and JC-MN45; courtesy Dr. Slife, Galesburg, Dr. van Alstine, West Lafayette, and Dr. Collins, St. Paul), and Canada (RB-16, RB- 19, RB-22 and RB-23; courtesy Dr. Robinson, Quebec).
[0091] The experimental sera were: The above described set of sera of pigs 21, 23, 25, and 29, taken at dpi 0, 14, 28, and 42. A set of experimental sera (obtained by courtesy of Drs. Chladek, St. Joseph, and Collins, St. Paul) that originated from four six-month-old gilts that were challenged intranasally with 10 5.1 TCID 50 of the isolate ATCC VR-2332. Blood samples were taken from gilt 2B at 0, 20, 36, and 63 dpi; from gilt 9G at 0, 30, 44, and 68 dpi; from gilt 16W at 0, 25, 40, and 64 dpi; and from gilt 16Y at 0, 36, and 64 dpi.
[0092] To study by radio-immunoprecipitation assay (RIP; de Mazancourt et al., 1986) the proteins of LA in infected porcine alveolar macrophages, we grew LA-infected and uninfected macrophages for 16 hours in the presence of labeling medium containing 35 S-Cysteine. Then the labeled cells were precipitated according to standard methods with 42 dpi post-infection sera of pig b 822 and pig 23 and with serum MN 8 which was obtained 26 days after infecting a sow with the isolate ATCC VR-2332 (courtesy Dr. Collins, St. Paul). The precipitated proteins were analyzed by electrophoresis in a 12% SDS-PAGE gel and visualized by fluorography.
[0093] To characterize the genome of LA, we extracted nuclear DNA and cytoplasmatic RNA from macrophage cultures that were infected with LA and grown for 24 h or were left uninfected. The cell culture medium was discarded, and the cells were washed twice with phosphate-buffered saline. DNA was extracted as described (Strauss, 1987). The cytoplasmic RNA was extracted as described (Favaloro et al., 1980), purified by centrifugation through a 5.7 M CsCl cushion (Setzer et al., 1980), treated with RNase-free DNase (Pharmacia), and analyzed in a 0.8% neutral agarose gel (Moormann and Hulst, 1988).
[0094] Cloning and Sequencing
[0095] To clone LV RNA, intracellular RNA of LV-infected porcine lung alveolar macrophages (10 μg) was incubated with 10 mM methylmercury hydroxide for 10 minutes at room temperature. The denatured RNA was incubated at 42° C. with 50 mM Tris-HCI, pH 7.8, 10 mM MgCl 2 , 70 mM KCl, 0.5 mM dATP, dCTP, dGTP and dTTP, 0.6 μg calf thymus oligonucleotide primers pd(N)6 (Pharmacia) and 300 units of Moloney murine leukemia virus reverse transcriptase (Bethesda Research Laboratories) in a total volume of 100μl 20 mM EDTA was added after 1 hr; the reaction mixture was then extracted with phenol/chloroform, passed through a Sephadex G50 column and precipitated with ethanol.
[0096] For synthesis of the second cDNA strand, DNA polymerase I (Boehringer) and RNase H (Pharmacia) were used (Gübler and Hoffinan, 1983). To generate blunt ends at the termini, double-stranded cDNA was incubated with T4 DNA polymerase (Pharmacia) in a reaction mixture which contained 0.05 mM deoxynucleotide-triphosphates. Subsequently, cDNA was fractionated in a 0.8% neutral agarose gel (Moormann and Hulst, 1988). Fragments of 1 to 4 kb were electroeluted, ligated into the Smal site of pGEM-4Z (Promega), and used for transformation of Escherichia coli strain DH5α (Hanahan, 1985). Colony filters were hybridized with a 32 P-labeled single-stranded cDNA probe. The probe was reverse transcribed from LV RNA which had been fractionated in a neutral agarose gel (Moormann and Hulst, 1988). Before use, the single stranded DNA probe was incubated with cytoplasmic RNA from mock-infected lung alveolar macrophages.
[0097] The relationship between LV cDNA clones was determined by restriction enzyme analysis and by hybridization of Southern blots of the digested DNA with nick-translated cDNA probes (Sambrook et al., 1989).
[0098] To obtain the 3′ end of the viral genome, we constructed a second cDNA library, using oligo (dT) 12-18 and a 3′ LV-specific oligonucleotide that was complementary to the minus-strand viral genome as a primer in the first-strand reaction. The reaction conditions for first- and second-strand synthesis were identical to those described above. This library was screened with virus-specific 3′ end oligonucleotide probes.
[0099] Most (>95%) of the cDNA sequences were determined with an Automated Laser Fluorescent A.L.F.™. DNA sequencer from Pharmacia LKB. Fluorescent oligonucleotide primer directed sequencing was performed on double-stranded DNA using the AutoRead™. Sequencing Kit (Pharmacia) essentially according to procedures C and D described in the Autoread™ Sequencing Kit protocol. Fluorescent primers were prepared with FluorePrime™. (Pharmacia). The remaining part of the sequence was determined via double-stranded DNA sequencing using oligonucleotide primers in conjunction with a T7 polymerase based sequencing kit (Pharmacia) and α- 32 S-dATP (Amersham). Sequence data were analyzed using the sequence analysis programs PCGENE (Intelligenetics, Inc, Mountain View, U.S.A.) and FASTA (Pearson and Lipman, 1988).
[0100] Experimental Reproduction of MSD
[0101] Fourteen conventionally reared pregnant sows that were pregnant for 10-11 weeks were tested for antibody against LA in the IPMA. All were negative. Then two groups of four sows were formed and brought to the CVI. At week 12 of gestation, these sows were inoculated intranasally with 2 ml LA (passage level 3, titre 10 4.8 TCID 50 /ml). Serum and EDTA blood samples were taken at day 10 after inoculation. Food intake, rectal temperature, and other clinical symptoms were observed daily. At farrowing, the date of birth and the number of dead and living piglets per sow were recorded, and samples were taken for virus isolation and serology.
Results
[0102] Immunofluorescence
[0103] Tissue sections of pigs with MSD were stained in an IFT with FITC-conjugates directed against African swine fever virus, hog cholera virus, pseudorabies virus, porcine parvo virus, porcine influenza virus, encephalomyocarditis virus and Chlamydia psittaci. The sections were stained, examined by fluorescent microscopy and all were found negative.
[0104] Virus Isolation from Piglets from MSD Affected Farms
[0105] Cytopathic isolates were detected in macrophage cultures inoculated with tissue samples of MSD affected, two-to-ten day old piglets. Sixteen out of 19 piglets originating from five different farms were positive (Table 1A). These isolates all reacted in IPMA with the post-infection serum of pig c 829, whereas non-inoculated control cultures did not react. The isolates, therefore, were representatives of LA. One time a cytopathic isolate was detected in an SK-6 cell culture inoculated with a suspension of an oral swab from a piglet from a sixth farm (farm VE) (Table 1A). This isolate showed characteristics of the picoma viridae and was neutralized by serum specific for PEV 2, therefore, the isolate was identified as PEV 2 (Table 3). PK2, PK-15 cells and hen eggs inoculated with samples from this group remained negative throughout.
[0106] Virus Isolation from Sows from MSD Affected Farms
[0107] Cytopathic isolates were detected in macrophage cultures inoculated with samples of MSD affected sows. 41 out of 63 sows originating from 11 farms were positive (Table 1B). These isolates all reacted in IPMA with the post-infection serum of pig b 822 and were, therefore, representatives of LA. On one occasion a cytopathic isolate was detected in a PK2 cell culture inoculated with a suspension of a leucocyte fraction of a sow from farm HU (Table 1B). This isolate showed characteristics of the picoma viridae and was neutralized by serum specific for EMCV, therefore, the isolate was identified as EMCV (Table 3). SK-6, PK-15 cells and hen eggs inoculated with samples from this group remained negative.
[0108] Virus Isolation from SPF Pigs Kept in Contact with MSD Affected Sows
[0109] Cytopathic isolates were detected in macrophage cultures inoculated with samples of SPF pigs kept in contact with MSD affected sows. Four of the 12 pigs were positive (Table 2). These isolates all reacted in IPMA with the post-infection serum of pig c 829 and of pig b 822 and were, therefore, representatives of LA. Cytopathic isolates were also detected in PK2, PK-15 and SK-6 cell cultures inoculated with samples of these SPF pigs. Seven of the 12 pigs were positive (Table 2), these isolates were all neutralized by serum directed against PEV 7. One of these seven isolates was studied further and other characteristics also identified the isolate as PEV 7 (Table 3).
[0110] Virus Isolation from SPF Pigs Inoculated with Blood of MSD Affected Sows
[0111] Cytopathic isolates were detected in macrophage cultures inoculated with samples of SPF pigs inoculated with blood of MSD affected sows. Two out of the eight pigs were positive (Table 2). These isolates all reacted in IPMA with the post-infection serum of pig c 829 and of pig b 822 and were, therefore, representatives of LA. PK2, SK-6 and PK-15 cells inoculated with samples from this group remained negative.
[0112] Summarizing, four groups of pigs were tested for the presence of agents that could be associated with mystery swine disease (MSD).
[0113] In group one, MSD affected piglets, the Lelystad Agent (LA) was isolated from 16 out of 20 piglets; one time PEV 2 was isolated.
[0114] In group two, MSD affected sows, the Lelystad Agent was isolated from 41 out of 63 sows; one time EMCV was isolated. Furthermore, 123 out of 165 MSD affected sows seroconverted to the Lelystad Agent, as tested in the IPMA. Such massive seroconversion was not demonstrated against any of the other viral pathogens tested.
[0115] In group three, SPF pigs kept in contact with MSD affected sows, LA was isolated from four of the 12 pigs; PEV 7 was isolated from seven pigs. All 12 pigs seroconverted to LA and PEV 7.
[0116] In group four, SPF pigs inoculated with blood of MSD affected sows, the LA was isolated from two pigs. All eight pigs seroconverted to LA.
[0117] Serology of Sows from MSD Affected Farms
[0118] Paired sera from sows affected with MSD were tested against a variety of viral pathogens and against the isolates obtained during this study (Table 4). An overwhelming antibody response directed against LA was measured in the IPMA (75% of the sows seroconverted, in 23 out of the 26 farms seroconversion was found), whereas with none of the other viral pathogens a clear pattern of seroconversion was found. Neutralizing antibody directed against LA was not detected.
[0119] Serology of SPF Pigs Kept in Contact with MSD Affected Sows
[0120] All eight SPF pigs showed an antibody response in the IPMA against LA (Table 5). None of these sera were positive in the IPMA performed on uninfected macrophages. None of these sera were positive in the SNT for LA. The sera taken two weeks after contact had all high neutralizing antibody titres (>1280) against PEV 7, whereas the pre-infection sera were negative (<10), indicating that all pigs had also been infected with PEV 7.
[0121] Serology of SPF Pigs Inoculated with Blood of MSD Affected Sows
[0122] All eight SPF pigs showed an antibodyresponse in the IPMA against LA (Table 5). None of these sera were positive in the IPMA performed on uninfected macrophages. None of these sera were positive in the SNT for LA. The pre- and two weeks post-inoculation sera were negative (<10) against PEV 7.
[0123] Further Identification of Lelystad Agent
[0124] LA did not haemagglutinate with chicken, guinea pig, pig, sheep, or human O red blood cells.
[0125] LA did not react in IPMA with sera directed against PRV, TGE, PED, ASFV, etc.
[0126] After two blind passages, LA did not grow in PK2, PK-15, or SK-6 cells, or in embryonated hen eggs, inoculated through the allantoic route.
[0127] LA was still infectious after it was filtered through a 0.2 micron filter, titres before and after filitration were 10 5.05 and 10 5.3 TCID 50 as detected by IPMA.
[0128] Growth curve of LA (see FIG. 3). Maximum titres of cell-free virus were approximately 10 5.5 TCID 50 ml −1 from 32-48 h after inoculation. After that time the macrophages he cytopathic effect of LA.
[0129] Electronmicroscopy. Clusters of spherical LA particles were found. The particles measured 45-55 nm in diameter and contained a 30-35 nm nucleocapsid that was surrounded by a lipid bilayer membrane. LA particles were not found in infected cultures that were treated with negative serum or in negative control preparations.
[0130] Isolates from the Netherlands, Germany, and the United States. All seven isolates were isolated in porcine alveolar macrophages and passaged three to five times. All isolates caused a cytopathic effect in macrophages and could be specifically immunostained with anti-LA sera b 822 and the 42 dpi serum 23. The isolates were named NL2, GE1, GE 2, US1, US2, and US3.
[0131] Antigenic relationships ofisolates NL1, NL2, GE1, GE2, US 1, US2, and US3. None of the field sera reacted in IPMA with uninfected macrophages but all sera contained antibodies directed against one or more of the seven isolates (Table 7). None of the experimental sera reacted in IPMA with uninfected macrophages, and none of the 0 dpi experimental sera reacted with any of the seven isolates in IPMA (Table 8). All seven LA isolates reacted with all or most of the sera from the set of experimental sera of pigs 21, 23, 25, and 29, taken after 0 dpi. Only the isolates US1, US2, and US3 reacted with all or most of the sera from the set of experimental sera of gilts 2B, 9G, 16W, and 16Y, taken after 0 dpi.
[0132] Radioimmunoprecipitation studies. Seven LA-specific proteins were detected in LA-infected macrophages but not in uninfected macrophages precipitated with the 42 dpi sera of pigs b 822 and 23. The proteins had estimated molecular weights of 65, 39, 35, 26, 19, 16, and 15 kilodalton. Only two of these LA-specific proteins, of 16 and 15 kilodalton, were also precipitated by the 26 dpi serum MN8.
[0133] Sequence and Organization of the Genome of LV
[0134] The nature of the genome of LV was determined by analyzing DNA and RNA from infected porcine lung alveolar macrophages. No LV-specific DNA was detected. However, we did detect LV-specific RNA. In a 0.8% neutral agarose gel, LV RNA migrated slightly slower than a preparation of hog cholera virus RNA of 12.3 kb (Moormann et al., 1990) did. Although no accurate size determination can be performed in neutral agarose gels, it was estimated that the LV-specific RNA is about 14.5 to 15.5 kb in length.
[0135] To determine the complexity of the LV-specific RNAs in infected cells and to establish the nucleotide sequence of the genome of LV, we prepared cDNA from RNA of LV-infected porcine lung alveolar macrophages and selected and mapped LV-specific cDNA clones as described under Materials and Methods. The specificity of the cDNA clones was reconfirmed by hybridizing specific clones, located throughout the overlapping cDNA sequence, to Northern blots carrying RNA of LV-infected and uninfected macrophages. Remarkably, some of the cDNA clones hybridized with the 14.5 to 15.5 kb RNA detected in infected macrophages only, whereas others hybridized with the 14.5 to 15.5 kb RNA as well as with a panel of 4 or 5 RNAs of lower molecular weight (estimated size, 1 to 4 kb). The latter clones were all clustered at one end of the cDNA map and covered about 4 kb of DNA. These data suggested that the genome organization of LV may be similar to that of coronaviridae (Spaan et al., 1988), Berne virus (BEV; Snijder et al., 1990b), a torovirus, and EAV (de Vries et al., 1990), i.e., besides a genomic RNA there are subgenomic mRNAs which form a nested set which is located at the 3′ end of the genome. This assumption was confirmed when sequences of the cDNA clones became available and specific primers could be selected to probe the blots with. A compilation of the hybridization data obtained with cDNA clones and specific primers, which were hybridized to Northern blots carrying the RNA of LV-infected and uninfected macrophages, is shown in FIG. 2. Clones 12 and 20 which are located in the 5′ part and the centre of the sequence, respectively, hybridize to the 14.5 to 15.5 kb genomic RNA detected in LV-infected cells only. Clones 41 and 39, however, recognize the 14.5 to 15.5 kb genomic RNA and a set of 4 and 5 RNAs of lower molecular weight, respectively. The most instructive and conclusive hybridization pattern, however, was obtained with primer 25, which is located at the ultimate 5′ end in the LV sequence (compare FIG. 1). Primer 25 hybridized to a panel of 7 RNAs, with an estimated molecular weight ranging in size from 0.7 to 3.3 kb (subgenomic mRNAs), as well as the genomic RNA. The most likely explanation for the hybridization pattern of primer 25 is that 5′ end genomic sequences, the length of which is yet unknown, fuse with the body of the mRNAs which are transcribed from the 3′ end of the genome. In fact, the hybridization pattern obtained with primer 25 suggests that 5′ end genomic sequences function as a so called “leader sequence” in subgenomic mRNAs. Such a transcription pattern is a hallmark of replication of coronaviridae (Spaan et al., 1988), and of EAV (de Vries et al., 1990).
[0136] The only remarkable discrepancy between LV and EAV which could be extracted from the above data is that the genome size of LV is about 2.5 kb larger than that of EAV.
[0137] The consensus nucleotide sequence of overlapping cDNA clones is shown in FIG. 1 (SEQ ID NO: 1). The length of the sequence is 15,088 basepairs, which is in good agreement with the estimated size of the genomic LV RNA.
[0138] Since the LV cDNA library was made by random priming of the reverse transcriptase reaction with calf thymus pd(N) 6 primers, no cDNA clones were obtained which started with a poly-A stretch at their 3′ end. To clone the 3′ end of the viral genome, we constructed a second cDNA library, using oligo (dT) and primer 39U183R in the reverse transcriptase reaction. Primer 39U183R is complementary to LV minus-strand RNA, which is likely present in a preparation of RNA isolated from LV-infected cells. This library was screened with virus-specific probes (nick-translated cDNA clone 119 and oligonucleotide 119R64R), resulting in the isolation of five additional cDNA clones (e.g., cDNA clone 151, FIG. 2). Sequencing of these cDNA clones revealed that LV contains a 3′ poly(A) tail. The length of the poly(A) tail varied between the various cDNA clones, but its maximum length was twenty nucleotides. Besides clone 25 and 155 (FIG. 2), four additional cDNA clones were isolated at the 5′ end of the genome, which were only two to three nucleotides shorter than the ultimate 5′ nucleotide shown in FIG. 1 (SEQ ID NO: 1). Given this finding and given the way cDNA was synthesized, we assume to be very close to the 5′ end of the sequence of LV genomic RNA.
[0139] Nearly 75% of the genomic sequence of LV encodes ORF 1A and ORF 1B. ORF 1A probably initiates at the first AUG (nucleotide position 212, FIG. 1) encountered in the LV sequence. The C-terminus of ORF 1A overlaps the putative N-terminus of ORF 1 B over a small distance of 16 nucleotides. It thus seems that translation of ORF 1B proceeds via ribosomal frameshifling, a hallmark of the mode of translation of the polymerase or replicase gene of coronaviruses (Boursnell et al., 1987; Bredenbeek et al. 1990) and the torovirus BEV (Snijder et al., 1990a). The characteristic RNA pseudoknot structure which is predicted to be formed at the site of the ribosomal frameshifting is also found at this location in the sequence of LV (results not shown).
[0140] ORF 1B encodes an amino acid sequence (SEQ ID NO: 3) of nearly 1400 residues which is much smaller than ORF 1B of the coronaviruses MHV and IBV (about 3,700 amino acid residues; Bredenbeek et al., 1990; Boursnell et al., 1987) and BEV (about 2,300 amino acid residues; Snijder et al., 1990a). Characteristic features of the ORF 1B product (SEQ ID NO: 3) of members of the superfamily of coronaviridae, like the replicase motif and the Zinc finger domain, can also be found in ORF 1B of LV (results not shown).
[0141] Whereas ORF 1A and ORF 1B encode the viral polymerase (SEQ ID NO:2 and SEQ ID NO:3) and, therefore, are considered to encode a non-structural viral protein, ORFs 2 to 7 are believed to encode structural viral proteins (SEQ ID NOS:4-9).
[0142] The products of ORFs 2 to 6 (SEQ ID NOS:4-8) all show features reminiscent of membrane (envelope) associated proteins. ORF 2 encodes a protein (SEQ ID NO:4) of 249 amino acids containing two predicted N-linked glycosylation sites (Table 9). At the N-terminus a hydrophobic sequence, which may function as a so-called signal sequence, is identified. The C-terminus also ends with a hydrophobic sequence, which in this case may function as a transmembrane region, which anchors the ORF 2 product (SEQ ID NO:4) in the viral envelope membrane.
[0143] ORF 3 may initiate at the AUG starting at nucleotide position 12394 or at the AUG starting at nucleotide position 12556 and then encodes proteins (SEQ ID NO:5) of 265 and 211 amino acids, respectively. The protein of 265 residues contains seven putative N-linked glycosylation sites, whereas the protein of 211 residues contains four (Table 9). At the N-terminus of the protein (SEQ ID NO:5) of 265 residues a hydrophobic sequence is identified.
[0144] Judged by hydrophobicity analysis, the topology of the protein encoded by ORF 4 (SEQ ID NO:6) is similar to that encoded by ORF 2 (SEQ ID NO:4) if the product of ORF 4 (SEQ ID NO:6) initiates at the AUG starting at nucleotide position 12936. However, ORF 4 may also initiate at two other AUG codons (compare FIGS. 1 and 2) starting at positions 12981 and 13068 in the sequence respectively. Up to now it is unclear which start codon is used. Depending on the start codon used, ORF 4 may encode proteins (SEQ ID NO:6) of 183 amino acids containing four putative N-linked glycosylation sites, of 168 amino acids containing four putative N-linked glycosylation sites, or of 139 amino acids containing three putative N-linked glycosylation sites (Table 9).
[0145] ORF 5 is predicted to encode a protein (SEQ ID NO:7) of 201 amino acids having two putative N-linked glycosylation sites (Table 9). A characteristic feature of the ORF 5 product (SEQ ID NO:7) is the internal hydrophobic sequence between amino acid 108 to amino acid 132.
[0146] Analysis for membrane spanning segments andhydrophilicity of the product of ORF 6 (SEQ ID NO:8) shows that it contains three transmembrane spanning segments in the N-terminal 90 amino acids of its sequence. This remarkable feature is also a characteristic of the small envelope glycoprotein M or E1 of several coronaviruses, e.g., Infectious Bronchitis Virus (IBV; Boursnell et al., 1984) and Mouse Hepatitis Virus (MHV: Rottier et al., 1986). It is, therefore, predicted that the protein encoded by ORF 6 (SEQ ID NO:8) was a membrane topology analogous to that of the M or E1 protein of coronaviruses (Rottier et al., 1986). A second characteristic of the M or E1 protein is a so-called surface helix which is located immediately adjacent to the presumed third transmembrane region. This sequence of about 25 amino acids which is very well conserved among coronaviruses is also recognized, although much more degenerate, in LV. Yet we predict the product of LV ORF 6 (SEQ ID NO:8) to have an analogous membrane associated function as the coronavirus M or E1 protein. Furthermore, the protein encoded by ORF 6 (SEQ ID NO:8) showed a strong similarity (53% identical amino acids) with VpX (Godeny et al., 1990) of LDV.
[0147] The protein encoded by ORF 7 (SEQ ID NO:9) has a length of 128 amino acid residues (Table 9) which is 13 amino acids longer than Vp1 of LDV (Godeny et al., 1990). Yet a significant similarity (43% identical amino acids) was observed between the protein encoded by ORF 7 (SEQ ID NO:9) and Vp1. Another shared characteristic between the product of ORF 7 (SEQ ID NO:9) and Vp1 is the high concentration of basic residues (Arg, Lys and His) in the N-terminal half of the protein. Up to amino acid 55, the LV sequence contains 26% Arg, Lys and His. This finding is fully in line with the proposed function of the ORF 7 product (SEQ ID NO:9) or Vp1 (Godeny et al., 1990), namely encapsidation of the viral genomic RNA. On the basis of the above data, we propose the LV ORF 7 product (SEQ ID NO:9) to be the nucleocapsid protein N of the virus.
[0148] A schematic representation of the organization of the LV genome is shown in FIG. 2. The map of overlapping clones used to determine the sequence of LV is shown in the top panel. A linear compilation of this map indicating the 5′ and 3′ end of the nucleotide sequence of LV, shown in FIG. 1 (SEQ ID NO:1), including a division in kilobases, is shown below the map of cDNA clones and allows the positioning of these clones in the sequence. The position of the ORFs identified in the LV genome is indicated below the linear map of the LV sequence. The bottom panel shows the nested set of subgenomic mRNAs, and the position of these RNAs relative to the LV sequence.
[0149] In line with the translation strategy of coronavirus, torovirus and arterivirus subgenomic mRNAs, it is predicted that ORFs 1 to 6 are translated from the unique 5′ end of their genomic or mRNAs. This unique part of the mRNAs is considered to be that part of the RNA that is obtained when a lower molecular weight RNA is “subtracted” from the higher molecular weight RNA which is next in line. Although RNA 7 forms the 3′ end of all the other genomic and subgenomic RNAs, and thus does not have a unique region, it is believed that ORF 7 is only translated from this smallest sized mRNA. The “leader sequence” at the 5′ end of the subgenomic RNAs is indicated with a solid box. The length of this sequence is about 200 bases, but the precise site of fusion with the body of the genomic RNAs still has to be determined.
[0150] Experimental Reproduction of MSD
[0151] Eight pregnant sows were inoculated with LA and clinical signs of MSD such as inappetance and reproductive losses were reproduced in these sows. From day four to day 10-12 post-inoculation (p.i.), all sows showed a reluctance to eat. None of the sows had elevated body temperatures. Two sows had bluish ears at day 9 and 10 p.i. In Table 6 the day of birth and the number of living and dead piglets per sow is given. LA was isolated from 13 of the born piglets.
TABLE 1 Description and results of virus isolation of field samples. A Samples of piglets suspected of infection with MSD. number age farm of pigs days material used results* RB 5 2 lung, tonsil, and brains 5 × LA DV 4 3 lung, brains, 3 × LA pools of kidney, spleen TH 3 3-5 lung, pools of kidney, tonsil 3 × LA DO 3 10 lung, tonsil 2 × LA ZA 4 1 lung, tonsil 3 × LA VE 1 ? oral swab 1 × PEV 2 TOTAL 20 16 × LA, 1 × PEV 2 B Samples of sows suspected of infection with MSD. number farm of sows material used results TH 2 plasma and leucocytes 1 × LA HU 5 plasma and leucocytes 2 × LA, 1 × EMCV TS 10 plasma and leucocytes 6 × LA HK 5 plasma and leucocytes 2 × LA LA 6 plasma and leucocytes 2 × LA VL 6 serum and leucocytes 5 × LA TA 15 serum 11 × LA LO 4 plasma and leucocytes 2 × LA JA 8 plasma and leucocytes 8 × LA VD 1 plasma and leucocytes 1 × LA VW 1 serum 1 × LA TOTAL 63 41 × LA, 1 × EMCV
[0152] [0152] TABLE 2 Description and results of virus isolation of samples of pigs with experimentally induced infections. sow pig@ material used results* A (LO) # c 835 lung, tonsil 2 × LA c 836 nasal swabs 2 × PEV 7 c 837 nasal swabs B (JA) c 825 lung, tonsil c 821 nasal swabs 1 × PEV 7 c 823 nasal swabs 4 × PEV 7 C (JA) c 833 lung, tonsil 1 × LA, 1 × PEV 7 c 832 nasal swabs 2 × PEV 7 c 829 nasal swabs, plasma and 3 × LA, leucocytes 2 × PEV 7 D (VD) c 816 lung, tonsil c 813 nasal swabs 1 × LA c 815 nasal swabs 1 × PEV 7 TOTAL isolates from contact pigs 7 × LA, 13 × PEV 7 A b 809 nasal swabs b 817 nasal swabs B b 818 nasal swabs, plasma 1 × LA and leucocytes b 820 nasal swabs C b 822 nasal swabs b 826 nasal swabs D b 830 nasal swabs 1 × LA b 834 nasal swabs TOTAL isolates from blood inoculated pigs 2 × LA #a separate stable. EDTA blood for virus isolation from plasma and leucocytes was taken whenever a pig had fever.
[0153] [0153] TABLE 3 Identification of viral isolates buoyant 1 particle 2 neutralized by 4 origin and density size in sens 3 to serum directed cell culture in CsCl FM (nm) chloroform against (titre) leucocytes 1.33 g/ml 28-30 not sens. EMCV ( 1280) sow farm HU PK-15, PK2, SK6 oral swab ND 28-30 not sens. PEV 2 (>1280) piglet farm VE SK6 nasal swabs, ND 28-30 not sens. PEV 7 (>1280) tonsil SPF pigs CVI PK-15, PK2, SK6 various 1.19 g/ml pleomorf sens. none (all <5) samples various farms pig lung macrophages #entero viruses (PEV) 1 to 11 (courtesy Dr. Knowles, Pirbright, UK), against encephalomyocarditis virus (EMCV; courtesy Dr. Ahl, Tübingen, Germany), against porcine parvo virus, and against swine vesicular disease. #leukemia virus from the SPF-pigs (see Table 5).
[0154] [0154] TABLE 4 Results of serology of paired field sera taken from sows suspected to have MSD. Sera were taken in the acute phase of the disease and 3-9 weeks later. Given is the number of sows which showed a fourfold or higher rise in titre/number of sows tested. Interval i Farm in weeks HAI HEV H1N1 H3N2 ELISA PPV PPV BVDV HCV TH 3 0/6 0/6 0/6 0/6 0/6 0/5 0/6 RB 5 0/13 1/13 0/13 1/9 0/7 0/6 0/9 HU 4 0/5 0/5 3/5 0/5 0/5 0/5 0/5 TS 3 1/10 0/10 0/10 0/10 0/10 0/4 0/10 VL 3 0/5 0/5 0/5 0/5 1/5 0/5 0/5 JA 3 0/11 1/11 3/11 0/11 2/11 0/11 0/11 WE 4 1/6 1/6 1/6 3/7 3/7 0/7 0/7 GI 4 0/4 1/4 0/4 0/4 0/4 0/4 0/4 SE 5 0/8 0/8 0/8 0/8 0/6 0/3 0/8 KA 5 0/1 0/1 0/1 0/1 0/1 ND 0/1 HO 3 1/6 0/5 1/6 0/6 0/6 0/6 0/6 NY 4 0/5 1/5 1/5 0/3 0/4 0/2 0/4 JN 3 0/10 5/10 0/10 0/10 1/10 0/10 0/10 KO f 3 1/10 0/10 0/10 0/10 2/10 0/10 0/10 OE 9 ND ND ND 0/6 0/6 0/6 0/6 LO 6 ND ND ND 0/3 0/3 0/2 0/3 WI 4 ND ND ND 0/1 1/1 0/1 0/3 RR 3 ND ND ND 1/8 0/8 0/8 0/8 RY 4 ND ND ND 0/3 0/4 0/3 0/4 BE 5 ND ND ND 0/10 0/10 0/10 0/10 BU 3 ND ND ND 1/6 0/6 0/6 0/6 KR 3 ND ND ND 1/4 0/4 0/4 0/4 KW 5 ND ND ND 0/10 0/10 0/10 0/10 VR 5 ND ND ND 1/6 0/6 0/6 0/6 HU 4 ND ND ND 1/4 0/3 0/3 0/4 ME 3 ND ND ND 0/5 1/5 0/5 0/5 total negative n 19 41 29 97 16 140 165 total positive p 77 48 62 55 131 1 0 total sero-converted s 4 10 9 9 11 0 0 total tested 100 99 100 161 158 141 165 Interval SNT IPMA Farm in weeks EMCV EMCVi PEV2 PEV2i PEV7 PEV7i LA LA TH 3 0/6 0/6 0/5 0/5 0/6 0/5 0/6 6/6 RB 5 1/7 1/9 0/6 2/6 1/8 0/6 0/13 7/9 HU 4 ND 0/5 0/5 0/5 ND 0/5 0/5 5/5 TS 3 0/10 0/10 0/7 0/4 0/10 0/7 ND 10/10 VL 3 ND ND 1/5 0/5 ND 0/5 ND 5/5 JA 3 0/11 0/11 0/11 0/11 1/11 2/11 0/5 8/11 WE 4 1/7 1/6 1/6 1/7 1/7 1/7 0/7 7/7 GI 4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 SE 5 0/8 0/8 0/6 1/8 0/8 1/5 0/8 6/8 KA 5 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1 HO 3 0/6 0/6 0/6 0/6 0/6 0/6 0/6 4/6 NY 4 0/4 0/4 0/2 0/2 0/4 0/3 0/4 4/4 JN 3 0/10 0/10 1/10 0/9 0/10 0/10 0/10 5/10 KO f 3 0/10 0/10 2/10 2/10 1/10 3/10 ND 8/10 OE 9 0/6 0/6 1/6 1/5 ND 1/6 ND 4/6 LO 6 0/3 0/3 0/3 0/3 0/3 0/3 ND 3/3 WI 4 ND ND 0/1 0/1 ND 0/1 ND 0/3 RR 3 0/8 1/8 0/8 0/8 0/8 0/8 ND 8/8 RY 4 0/4 ND 0/4 0/1 ND 1/4 ND 1/4 BE 5 ND ND 0/10 0/10 ND 1/10 ND 0/10 BU 3 ND ND 0/6 0/6 ND 0/6 ND 6/6 KR 3 ND ND 0/4 0/4 ND 0/4 ND 1/4 KW 5 ND ND 0/10 0/10 ND 1/10 ND 10/10 VR 5 ND ND 0/6 1/6 ND 0/6 ND 6/6 HU 4 ND ND 0/3 0/4 ND 0/3 ND 3/4 ME 3 ND ND 0/5 0/5 ND 0/5 ND 2/5 total neg. n 15 29 0 0 2 1 69 15 total pos. p 88 74 144 138 90 136 0 27 total sero-converted s 2 3 6 8 4 10 0 123 total tested 105 107 150 146 96 147 69 165
[0155] [0155] TABLE 5 Development of antibody directed against Lelystad Agent as measured by IPMA. A contact pigs serum titres in IPMA Weeks post contact: Pig 0 2 3 4 5 c 836 0 10 640 640 640 c 837 0 10 640 640 640 c 821 0 640 640 640 640 c 823 0 160 2560 640 640 c 829 0 160 640 10240 10240 c 832 0 160 640 640 2560 c 813 0 640 2560 2560 2560 c 815 0 160 640 640 640 B blood inoculated pigs serum titres in IPMA Weeks post inoculation: Pig 0 2 3 4 6 b 809 0 640 2560 2560 2560 b 817 0 160 640 640 640 b 818 0 160 640 640 640 b 820 0 160 640 640 640 b 822 0 640 2560 2560 10240 b 826 0 640 640 640 10240 b 830 0 640 640 640 2560 b 834 0 160 640 2560 640
[0156] [0156] TABLE 6 Experimental reproduction of MSD. No. of piglets Length at birth No. of LA 1 in piglets of alive dead deaths born died in Sow gestation (Number Ab pos) 2 week 1 dead week 1 52 113 12 (5) 3 (2) 6 2 4 965 116 3 (0) 9 (3) 2 4 997 114 9 (0) 1 (0) 0 1305 116 7 (0) 2 (0) 1 134 109 4 (4) 7 (4) 4 3 941 117 7 10 1056 113 7 (1) 3 (0) 4 1065 115 9 2
[0157] [0157] TABLE 7 Reactivity in IPMA of a collection of field sera from Europe and North America tested with LA isolates from the Netherlands (NL1 and NL2), Germany (GE1 and GE2), and the United States (US1, US2 and US3). Isolates: NL1 NL2 GE1 GE2 US1 US2 US3 Sera from: The Netherlands TH-187 3.5 t 3.5 2.5 3.5 − − − TO-36 3.5 3.0 2.5 3.0 − 1.0 − Germany BE-352 4.0 3.5 2.5 3.0 − 1.5 − BE-392 3.5 3.5 2.5 2.5 1.5 1.5 0.5 NI-f2 2.5 1.5 2.0 2.5 − − − United Kingdom PA-141615 4.0 3.0 3.0 3.5 − − − PA-141617 4.0 3.5 3.0 3.5 − 2.5 2.0 PA-142440 3.5 3.0 2.5 3.5 − 2.0 2.5 Belgium PE-1960 4.5 4.5 3.0 4.0 1.5 − − France EA-2975 4.0 3.5 3.0 3.0 2.0 − − EA-2985 3.5 3.0 3.0 2.5 − − − United States SL-441 3.5 1.5 2.5 2.5 3.5 3.5 3.0 SL-451 3.0 2.0 2.5 2.5 3.5 4.5 4.0 AL-RP9577 1.5 − − 1.0 3.0 4.0 2.5 AL-P10814/33 0.5 2.5 − − 2.5 3.5 3.0 AL-4094A − − − − 1.0 2.0 0.5 AL-7525 − − − − − 1.0 − JC-MN41 − − − − 1.0 3.5 1.0 JC-MN44 − − − − 2.0 3.5 2.0 JC-MN45 − − − − 2.0 3.5 2.5 Canada RB-16 2.5 − 3.0 2.0 3.0 3.5 − RB-19 1.0 − 1.0 − 2.5 1.5 − RB-22 1.5 − 2.0 2.5 2.5 3.5 − RB-23 − − − − − 3.0 −
[0158] [0158] TABLE 8 Reactivity in IPMA of a collection of experimental sera raised against LA and SIRSV tested with LA isolates from the Netherlands (NL1 and NL2), Germany (GE1 and GE2), and the United States (US1, US2 and US3). Isolates: NL1 NL2 GE1 GE2 US1 US2 US3 Sera: anti-LA: 21 14 dpi 2.5 t 2.0 2.5 3.0 1.5 2.0 1.5 28 dpi 4.0 3.5 3.5 4.0 − 2.5 1.5 42 dpi 4.0 3.5 3.0 3.5 1.5 2.5 2.0 23 14 dpi 3.0 2.0 2.5 3.0 1.0 2.0 1.0 28 dpi 3.5 3.5 3.5 4.0 1.5 2.0 2.0 42 dpi 4.0 4.0 3.0 4.0 − 2.5 2.5 25 14 dpi 2.5 2.0 2.5 3.0 1.5 2.0 1.0 28 dpi 4.0 3.5 4.0 3.5 − 1.5 2.0 42 dpi 3.5 4.0 3.5 3.5 1.5 2.0 2.0 29 14 dpi 3.5 3.5 3.0 3.5 − 2.0 1.5 28 dpi 3.5 3.5 3.0 3.5 − 2.5 2.0 42 dpi 4.0 3.5 3.5 4.0 1.5 2.5 2.5 anti- SIRSV: 2B 20 dpi − − − − 2.0 2.0 − 36 dpi − − − − 1.5 2.0 − 63 dpi − − − − 1.0 1.0 − 9G 30 dpi − − − − 2.5 3.0 − 44 dpi − − − − 2.5 3.5 − 68 dpi − − − − 2.0 3.5 1.5 16W 25 dpi − − − − 2.0 3.0 − 40 dpi − − − − 2.0 3.0 − 64 dpi − − − − 2.5 2.5 1.5 16Y 36 dpi − − − − 1.0 3.0 1.0 64 dpi − − − − 2.5 3.0 −
[0159] [0159] TABLE 9 Characteristics of the ORFs of Lelystad Virus. Calculated No. of size of the number of Nucleotides amino unmodified glycosylation ORF (first-last) acids peptide (kDa) sites ORF1A 212-7399 2396 260.0 3 (SEQ ID NO: 2) ORF1B 7384-11772 1463 161.8 3 (SEQ ID NO: 3) ORF2 11786-12532 249 28.4 2 (SEQ ID NO: 4) ORF3 12394-13188 265 30.6 7 (SEQ ID NO: 5) 12556-13188 211 24.5 4 ORF4 12936-13484 183 20.0 4 (SEQ ID NO: 6) 12981-13484 168 18.4 4 13068-13484 139 15.4 3 ORF5 13484-14086 201 22.4 2 (SEQ ID NO: 7) ORF6 14077-14595 173 18.9 2 (SEQ ID NO: 8) ORF7 14588-14971 128 13.8 1 (SEQ ID NO: 9)
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1
9
15108 base pairs
nucleic acid
single
linear
DNA (genomic)
CDS
212..7399
CDS
7384..11772
CDS
11786..12532
CDS
12394..13188
CDS
12936..13484
CDS
13484..14086
CDS
14077..14595
CDS
14588..14971
1
GGGTATTCCC CCTACATACA CGACACTTCT AGTGTTTGTG TACCTTGGAG GCGTGGGTAC 60
AGCCCCGCCC CACCCCTTGG CCCCTGTTCT AGCCCAACAG GTATCCTTCT CTCTCGGGGC 120
GAGTGCGCCG CCTGCTGCTC CCTTGCAGCG GGAAGGACCT CCCGAGTATT TCCGGAGAGC 180
ACCTGCTTTA CGGGATCTCC ACCCTTTAAC C ATGTCTGGGA CGTTCTCCCG 231
GTGCATGTGC ACCCCGGCTG CCCGGGTATT TTGGAACGCC GGCCAAGTCT TTTGCACACG 291
GTGTCTCAGT GCGCGGTCTC TTCTCTCTCC AGAGCTTCAG GACACTGACC TCGGTGCAGT 351
TGGCTTGTTT TACAAGCCTA GGGACAAGCT TCACTGGAAA GTCCCTATCG GCATCCCTCA 411
GGTGGAATGT ACTCCATCCG GGTGCTGTTG GCTCTCAGCT GTTTTCCCTT TGGCGCGTAT 471
GACCTCCGGC AATCACAACT TCCTCCAACG ACTTGTGAAG GTTGCTGATG TTTTGTACCG 531
TGACGGTTGC TTGGCACCTC GACACCTTCG TGAACTCCAA GTTTACGAGC GCGGCTGCAA 591
CTGGTACCCG ATCACGGGGC CCGTGCCCGG GATGGGTTTG TTTGCGAACT CCATGCACGT 651
ATCCGACCAG CCGTTCCCTG GTGCCACCCA TGTGTTGACT AACTCGCCTT TGCCTCAACA 711
GGCTTGTCGG CAGCCGTTCT GTCCATTTGA GGAGGCTCAT TCTAGCGTGT ACAGGTGGAA 771
GAAATTTGTG GTTTTCACGG ACTCCTCCCT CAACGGTCGA TCTCGCATGA TGTGGACGCC 831
GGAATCCGAT GATTCAGCCG CCCTGGAGGT ACTACCGCCT GAGTTAGAAC GTCAGGTCGA 891
AATCCTCATT CGGAGTTTTC CTGCTCATCA CCCTGTCGAC CTGGCCGACT GGGAGCTCAC 951
TGAGTCCCCT GAGAACGGTT TTTCCTTCAA CACGTCTCAT TCTTGCGGTC ACCTTGTCCA 1011
GAACCCCGAC GTGTTTGATG GCAAGTGCTG GCTCTCCTGC TTTTTGGGCC AGTCGGTCGA 1071
AGTGCGCTGC CATGAGGAAC ATCTAGCTGA CGCCTTCGGT TACCAAACCA AGTGGGGCGT 1131
GCATGGTAAG TACCTCCAGC GCAGGCTTCA AGTTCGCGGC ATTCGTGCTG TAGTCGATCC 1191
TGATGGTCCC ATTCACGTTG AAGCGCTGTC TTGCCCCCAG TCTTGGATCA GGCACCTGAC 1251
TCTGGATGAT GATGTCACCC CAGGATTCGT TCGCCTGACA TCCCTTCGCA TTGTGCCGAA 1311
CACAGAGCCT ACCACTTCCC GGATCTTTCG GTTTGGAGCG CATAAGTGGT ATGGCGCTGC 1371
CGGCAAACGG GCTCGTGCTA AGCGTGCCGC TAAAAGTGAG AAGGATTCGG CTCCCACCCC 1431
CAAGGTTGCC CTGCCGGTCC CCACCTGTGG AATTACCACC TACTCTCCAC CGACAGACGG 1491
GTCTTGTGGT TGGCATGTCC TTGCCGCCAT AATGAACCGG ATGATAAATG GTGACTTCAC 1551
GTCCCCTCTG ACTCAGTACA ACAGACCAGA GGATGATTGG GCTTCTGATT ATGATCTTGT 1611
TCAGGCGATT CAATGTCTAC GACTGCCTGC TACCGTGGTT CGGAATCGCG CCTGTCCTAA 1671
CGCCAAGTAC CTTATAAAAC TTAACGGAGT TCACTGGGAG GTAGAGGTGA GGTCTGGAAT 1731
GGCTCCTCGC TCCCTTTCTC GTGAATGTGT GGTTGGCGTT TGCTCTGAAG GCTGTGTCGC 1791
ACCGCCTTAT CCAGCAGACG GGCTACCTAA ACGTGCACTC GAGGCCTTGG CGTCTGCTTA 1851
CAGACTACCC TCCGATTGTG TTAGCTCTGG TATTGCTGAC TTTCTTGCTA ATCCACCTCC 1911
TCAGGAATTC TGGACCCTCG ACAAAATGTT GACCTCCCCG TCACCAGAGC GGTCCGGCTT 1971
CTCTAGTTTG TATAAATTAC TATTAGAGGT TGTTCCGCAA AAATGCGGTG CCACGGAAGG 2031
GGCTTTCATC TATGCTGTTG AGAGGATGTT GAAGGATTGT CCGAGCTCCA AACAGGCCAT 2091
GGCCCTTCTG GCAAAAATTA AAGTTCCATC CTCAAAGGCC CCGTCTGTGT CCCTGGACGA 2151
GTGTTTCCCT ACGGATGTTT TAGCCGACTT CGAGCCAGCA TCTCAGGAAA GGCCCCAAAG 2211
TTCCGGCGCT GCTGTTGTCC TGTGTTCACC GGATGCAAAA GAGTTCGAGG AAGCAGCCCC 2271
RGAAGAAGTT CAAGAGAGTG GCCACAAGGC CGTCCACTCT GCACTCCTTG CCGAGGGTCC 2331
TAACAATGAG CAGGTACAGG TGGTTGCCGG TGAGCAACTG AAGCTCGGCG GTTGTGGTTT 2391
GGCAGTCGGG AATGCTCATG AAGGTGCTCT GGTCTCAGCT GGTCTAATTA ACCTGGTAGG 2451
CGGGAATTTG TCCCCCTCAG ACCCCATGAA AGAAAACATG CTCAATAGCC GGGAAGACGA 2511
ACCACTGGAT TTGTCCCAAC CAGCACCAGC TTCCACAACG ACCCTTGTGA GAGAGCAAAC 2571
ACCCGACAAC CCAGGTTCTG ATGCCGGTGC CCTCCCCGTC ACCGTTCGAG AATTTGTCCC 2631
GACGGGGCCT ATACTCTGTC ATGTTGAGCA CTGCGGCACG GAGTCGGGCG ACAGCAGTTC 2691
GCCTTTGGAT CTATCTGATG CGCAAACCCT GGACCAGCCT TTAAATCTAT CCCTGGCCGC 2751
TTGGCCAGTG AGGGCCACCG CGTCTGACCC TGGCTGGGTC CACGGTAGGC GCGAGCCTGT 2811
CTTTGTAAAG CCTCGAAATG CTTTCTCTGA TGGCGATTCA GCCCTTCAGT TCGGGGAGCT 2871
TTCTGAATCC AGCTCTGTCA TCGAGTTTGA CCGGACAAAA GATGCTCCGG TGGTTGACGC 2931
CCCTGTCGAC TTGACGACTT CGAACGAGGC CCTCTCTGTA GTCGATCCTT TCGAATTTGC 2991
CGAACTCAAG CGCCCGCGTT TCTCCGCACA AGCCTTAATT GACCGAGGCG GTCCACTTGC 3051
CGATGTCCAT GCAAAAATAA AGAACCGGGT ATATGAACAG TGCCTCCAAG CTTGTGAGCC 3111
CGGTAGTCGT GCAACCCCAG CCACCAGGGA GTGGCTCGAC AAAATGTGGG ATAGGGTGGA 3171
CATGAAAACT TGGCGCTGCA CCTCGCAGTT CCAAGCTGGT CGCATTCTTG CGTCCCTCAA 3231
ATTCCTCCCT GACATGATTC AAGACACACC GCCTCCTGTT CCCAGGAAGA ACCGAGCTAG 3291
TGACAATGCC GGCCTGAAGC AACTGGTGGC ACAGTGGGAT AGGAAATTGA GTGTGACCCC 3351
CCCCCCAAAA CCGGTTGGGC CAGTGCTTGA CCAGATCGTC CCTCCGCCTA CGGATATCCA 3411
GCAAGAAGAT GTCACCCCCT CCGATGGGCC ACCCCATGCG CCGGATTTTC CTAGTCGAGT 3471
GAGCACGGGC GGGAGTTGGA AAGGCCTTAT GCTTTCCGGC ACCCGTCTCG CGGGGTCTAT 3531
CAGCCAGCGC CTTATGACAT GGGTTTTTGA AGTTTTCTCC CACCTCCCAG CTTTTATGCT 3591
CACACTTTTC TCGCCGCGGG GCTCTATGGC TCCAGGTGAT TGGTTGTTTG CAGGTGTCGT 3651
TTTACTTGCT CTCTTGCTCT GTCGTTCTTA CCCGATACTC GGATGCCTTC CCTTATTGGG 3711
TGTCTTTTCT GGTTCTTTGC GGCGTGTTCG TCTGGGTGTT TTTGGTTCTT GGATGGCTTT 3771
TGCTGTATTT TTATTCTCGA CTCCATCCAA CCCAGTCGGT TCTTCTTGTG ACCACGATTC 3831
GCCGGAGTGT CATGCTGAGC TTTTGGCTCT TGAGCAGCGC CAACTTTGGG AACCTGTGCG 3891
CGGCCTTGTG GTCGGCCCCT CAGGCCTCTT ATGTGTCATT CTTGGCAAGT TACTCGGTGG 3951
GTCACGTTAT CTCTGGCATG TTCTCCTACG TTTATGCATG CTTGCAGATT TGGCCCTTTC 4011
TCTTGTTTAT GTGGTGTCCC AGGGGCGTTG TCACAAGTGT TGGGGAAAGT GTATAAGGAC 4071
AGCTCCTGCG GAGGTGGCTC TTAATGTATT TCCTTTCTCG CGCGCCACCC GTGTCTCTCT 4131
TGTATCCTTG TGTGATCGAT TCCAAACGCC AAAAGGGGTT GATCCTGTGC ACTTGGCAAC 4191
GGGTTGGCGC GGGTGCTGGC GTGGTGAGAG CCCCATCCAT CAACCACACC AAAAGCCCAT 4251
AGCTTATGCC AATTTGGATG AAAAGAAAAT GTCTGCCCAA ACGGTGGTTG CTGTCCCATA 4311
CGATCCCAGT CAGGCTATCA AATGCCTGAA AGTTCTGCAG GCGGGAGGGG CCATCGTGGA 4371
CCAGCCTACA CCTGAGGTCG TTCGTGTGTC CGAGATCCCC TTCTCAGCCC CATTTTTCCC 4431
AAAAGTTCCA GTCAACCCAG ATTGCAGGGT TGTGGTAGAT TCGGACACTT TTGTGGCTGC 4491
GGTTCGCTGC GGTTACTCGA CAGCACAACT GGTYCTGGGC CGGGGCAACT TTGCCAAGTT 4551
AAATCAGACC CCCCCCAGGA ACTCTATCTC CACCAAAACG ACTGGTGGGG CCTCTTACAC 4611
CCTTGCTGTG GCTCAAGTGT CTGCGTGGAC TCTTGTTCAT TTCATCCTCG GTCTTTGGTT 4671
CACATCACCT CAAGTGTGTG GCCGAGGAAC CGCTGACCCA TGGTGTTCAA ATCCTTTTTC 4731
ATATCCTACC TATGGCCCCG GAGTTGTGTG CTCCTCTCGA CTTTGTGTGT CTGCCGACGG 4791
GGTCACCCTG CCATTGTTCT CAGCCGTGGC ACAACTCTCC GGTAGAGAGG TGGGGATTTT 4851
TATTTTGGTG CTCGTCTCCT TGACTGCTTT GGCCCACCGC ATGGCTCTTA AGGCAGACAT 4911
GTTAGTGGTC TTTTCGGCTT TTTGTGCTTA CGCCTGGCCC ATGAGCTCCT GGTTAATCTG 4971
CTTCTTTCCT ATACTCTTGA AGTGGGTTAC CCTTCACCCT CTTACTATGC TTTGGGTGCA 5031
CTCATTCTTG GTGTTTTGTC TGCCAGCAGC CGGCATCCTC TCACTAGGGA TAACTGGCCT 5091
TCTTTGGGCA ATTGGCCGCT TTACCCAGGT TGCCGGAATT ATTACACCTT ATGACATCCA 5151
CCAGTACACC TCTGGGCCAC GTGGTGCAGC TGCTGTGGCC ACAGCCCCAG AAGGCACTTA 5211
TATGGCCGCC GTCCGGAGAG CTGCTTTAAC TGGGCGAACT TTAATCTTCA CCCCGTCTGC 5271
AGTTGGATCC CTTCTCGAAG GTGCTTTCAG GACTCATAAA CCCTGCCTTA ACACCGTGAA 5331
TGTTGTAGGC TCTTCCCTTG GTTCCGGAGG GGTTTTCACC ATTGATGGCA GAAGAACTGT 5391
CGTCACTGCT GCCCATGTGT TGAACGGCGA CACAGCTAGA GTCACCGGCG ACTCCTACAA 5451
CCGCATGCAC ACTTTCAAGA CCAATGGTGA TTATGCCTGG TCCCATGCTG ATGACTGGCA 5511
GGGCGTTGCC CCTGTGGTCA AGGTTGCGAA GGGGTACCGC GGTCGTGCCT ACTGGCAAAC 5571
ATCAACTGGT GTCGAACCCG GTATCATTGG GGAAGGGTTC GCCTTCTGTT TTACTAACTG 5631
CGGCGATTCG GGGTCACCCG TCATCTCAGA ATCTGGTGAT CTTATTGGAA TCCACACCGG 5691
TTCAAACAAA CTTGGTTCTG GTCTTGTGAC AACCCCTGAA GGGGAGACCT GCACCATCAA 5751
AGAAACCAAG CTCTCTGACC TTTCCAGACA TTTTGCAGGC CCAAGCGTTC CTCTTGGGGA 5811
CATTAAATTG AGTCCGGCCA TCATCCCTGA TGTAACATCC ATTCCGAGTG ACTTGGCATC 5871
GCTCCTAGCC TCCGTCCCTG TAGTGGAAGG CGGCCTCTCG ACCGTTCAAC TTTTGTGTGT 5931
CTTTTTCCTT CTCTGGCGCA TGATGGGCCA TGCCTGGACA CCCATTGTTG CCGTGGGCTT 5991
CTTTTTGCTG AATGAAATTC TTCCAGCAGT TTTGGTCCGA GCCGTGTTTT CTTTTGCACT 6051
CTTTGTGCTT GCATGGGCCA CCCCCTGGTC TGCACAGGTG TTGATGATTA GACTCCTCAC 6111
GGCATCTCTC AACCGCAACA AGCTTTCTCT GGCGTTCTAC GCACTCGGGG GTGTCGTCGG 6171
TTTGGCAGCT GAAATCGGGA CTTTTGCTGG CAGATTGTCT GAATTGTCTC AAGCTCTTTC 6231
GACATACTGC TTCTTACCTA GGGTCCTTGC TATGACCAGT TGTGTTCCCA CCATCATCAT 6291
TGGTGGACTC CATACCCTCG GTGTGATTCT GTGGTTRTTC AAATACCGGT GCCTCCACAA 6351
CATGCTGGTT GGTGATGGGA GTTTTTCAAG CGCCTTCTTC CTACGGTATT TTGCAGAGGG 6411
TAATCTCAGA AAAGGTGTTT CACAGTCCTG TGGCATGAAT AACGAGTCCC TAACGGCTGC 6471
TTTAGCTTGC AAGTTGTCAC AGGCTGACCT TGATTTTTTG TCCAGCTTAA CGAACTTCAA 6531
GTGCTTTGTA TCTGCTTCAA ACATGAAAAA TGCTGCCGGC CAGTACATTG AAGCAGCGTA 6591
TGCCAAGGCC CTGCGCCAAG AGTTGGCCTC TCTAGTTCAG ATTGACAAAA TGAAAGGAGT 6651
TTTGTCCAAG CTCGAGGCCT TTGCTGAAAC AGCCACCCCG TCCCTTGACA TAGGTGACGT 6711
GATTGTTCTG CTTGGGCAAC ATCCTCACGG ATCCATCCTC GATATTAATG TGGGGACTGA 6771
AAGGAAAACT GTGTCCGTGC AAGAGACCCG GAGCCTAGGC GGCTCCAAAT TCAGTGTTTG 6831
TACTGTCGTG TCCAACACAC CCGTGGACGC CTTRACCGGC ATCCCACTCC AGACACCAAC 6891
CCCTCTTTTT GAGAATGGTC CGCGTCATCG CAGCGAGGAA GACGATCTTA AAGTCGAGAG 6951
GATGAAGAAA CACTGTGTAT CCCTCGGCTT CCACAACATC AATGGCAAAG TTTACTGCAA 7011
AATTTGGGAC AAGTCTACCG GTGACACCTT TTACACGGAT GATTCCCGGT ACACCCAAGA 7071
CCATGCTTTT CAGGACAGGT CAGCCGACTA CAGAGACAGG GACTATGAGG GTGTGCAAAC 7131
CACCCCCCAA CAGGGATTTG ATCCAAAGTC TGAAACCCCT GTTGGCACTG TTGTGATCGG 7191
CGGTATTACG TATAACAGGT ATCTGATCAA AGGTAAGGAG GTTCTGGTCC CCAAGCCTGA 7251
CAACTGCCTT GAAGCTGCCA AGCTGTCCCT TGAGCAAGCT CTCGCTGGGA TGGGCCAAAC 7311
TTGCGACCTT ACAGCTGCCG AGGTGGAAAA GCTAAAGCGC ATCATTAGTC AACTCCAAGG 7371
TTTGACCACT GAACAGGCTT TAAACTGT TAGCCGCCAG CGGCTTGACC CGCTGTGGCC 7429
GCGGCGGCCT AGTTGTGACT GAAACGGCGG TAAAAATTAT AAAATACCAC AGCAGAACTT 7489
TCACCTTAGG CCCTTTAGAC CTAAAAGTCA CTTCCGAGGT GGAGGTAAAG AAATCAACTG 7549
AGCAGGGCCA CGCTGTTGTG GCAAACTTAT GTTCCGGTGT CATCTTGATG AGACCTCACC 7609
CACCGTCCCT TGTCGACGTT CTTCTGAAAC CCGGACTTGA CACAATACCC GGCATTCAAC 7669
CAGGGCATGG GGCCGGGAAT ATGGGCGTGG ACGGTTCTAT TTGGGATTTT GAAACCGCAC 7729
CCACAAAGGC AGAACTCGAG TTATCCAAGC AAATAATCCA AGCATGTGAA GTTAGGCGCG 7789
GGGACGCCCC GAACCTCCAA CTCCCTTACA AGCTCTATCC TGTTAGGGGG GATCCTGAGC 7849
GGCATAAAGG CCGCCTTATC AATACCAGGT TTGGAGATTT ACCTTACAAA ACTCCTCAAG 7909
ACACCAAGTC CGCAATCCAC GCGGCTTGTT GCCTGCACCC CAACGGGGCC CCCGTGTCTG 7969
ATGGTAAATC CACACTAGGT ACCACTCTTC AACATGGTTT CGAGCTTTAT GTCCCTACTG 8029
TGCCCTATAG TGTCATGGAG TACCTTGATT CACGCCCTGA CACCCCTTTT ATGTGTACTA 8089
AACATGGCAC TTCCAAGGCT GCTGCAGAGG ACCTCCAAAA ATACGACCTA TCCACCCAAG 8149
GATTTGTCCT GCCTGGGGTC CTACGCCTAG TACGCAGATT CATCTTTGGC CATATTGGTA 8209
AGGCGCCGCC ATTGTTCCTC CCATCAACCT ATCCCGCCAA GAACTCTATG GCAGGGATCA 8269
ATGGCCAGAG GTTCCCAACA AAGGACGTTC AGAGCATACC TGAAATTGAT GAAATGTGTG 8329
CCCGCGCTGT CAAGGAGAAT TGGCAAACTG TGACACCTTG CACCCTCAAG AAACAGTACT 8389
GTTCCAAGCC CAAAACCAGG ACCATCCTGG GCACCAACAA CTTTATTGCC TTGGCTCACA 8449
GATCGGCGCT CAGTGGTGTC ACCCAGGCAT TCATGAAGAA GGCTTGGAAG TCCCCAATTG 8509
CCTTGGGGAA AAACAAATTC AAGGAGCTGC ATTGCACTGT CGCCGGCAGG TGTCTTGAGG 8569
CCGACTTGGC CTCCTGTGAC CGCAGCACCC CCGCCATTGT AAGATGGTTT GTTGCCAACC 8629
TCCTGTATGA ACTTGCAGGA TGTGAAGAGT ACTTGCCTAG CTATGTGCTT AATTGCTGCC 8689
ATGACCTCGT GGCAACACAG GATGGTGCCT TCACAAAACG CGGTGGCCTG TCGTCCGGGG 8749
ACCCCGTCAC CAGTGTGTCC AACACCGTAT ATTCACTGGT AATTTATGCC CAGCACATGG 8809
TATTGTCGGC CTTGAAAATG GGTCATGAAA TTGGTCTTAA GTTCCTCGAG GAACAGCTCA 8869
AGTTCGAGGA CCTCCTTGAA ATTCAGCCTA TGTTGGTATA CTCTGATGAT CTTGTCTTGT 8929
ACGCTGAAAG ACCCACMTTT CCCAATTACC ACTGGTGGGT CGAGCACCTT GACCTGATGC 8989
TGGGTTTCAG AACGGACCCA AAGAAAACCG TCATAACTGA TAAACCCAGC TTCCTCGGCT 9049
GCAGAATTGA GGCAGGGCGA CAGCTAGTCC CCAATCGCGA CCGCATCCTG GCTGCTCTTG 9109
CATATCACAT GAAGGCGCAG AACGCCTCAG AGTATTATGC GTCTGCTGCC GCAATCCTGA 9169
TGGATTCATG TGCTTGCATT GACCATGACC CTGAGTGGTA TGAGGACCTC ATCTGCGGTA 9229
TTGCCCGGTG CGCCCGCCAG GATGGTTATA GCTTCCCAGG TCCGGCATTT TTCATGTCCA 9289
TGTGGGAGAA GCTGAGAAGT CATAATGAAG GGAAGAAATT CCGCCACTGC GGCATCTGCG 9349
ACGCCAAAGC CGACTATGCG TCCGCCTGTG GGCTTGATTT GTGTTTGTTC CATTCGCACT 9409
TTCATCAACA CTGCCCYGTC ACTCTGAGCT GCGGTCACCA TGCCGGTTCA AAGGAATGTT 9469
CGCAGTGTCA GTCACCTGTT GGGGCTGGCA GATCCCCTCT TGATGCCGTG CTAAAACAAA 9529
TTCCATACAA ACCTCCTCGT ACTGTCATCA TGAAGGTGGG TAATAAAACA ACGGCCCTCG 9589
ATCCGGGGAG GTACCAGTCC CGTCGAGGTC TCGTTGCAGT CAAGAGGGGT ATTGCAGGCA 9649
ATGAAGTTGA TCTTTCTGAT GGRGACTACC AAGTGGTGCC TCTTTTGCCG ACTTGCAAAG 9709
ACATAAACAT GGTGAAGGTG GCTTGCAATG TACTACTCAG CAAGTTCATA GTAGGGCCAC 9769
CAGGTTCCGG AAAGACCACC TGGCTACTGA GTCAAGTCCA GGACGATGAT GTCATTTACA 9829
YACCCACCCA TCAGACTATG TTTGATATAG TCAGTGCTCT CAAAGTTTGC AGGTATTCCA 9889
TTCCAGGAGC CTCAGGACTC CCTTTCCCAC CACCTGCCAG GTCCGGGCCG TGGGTTAGGC 9949
TTATTGCCAG CGGGCACGTC CCTGGCCGAG TATCATACCT CGATGAGGCT GGATATTGTA 10009
ATCATCTGGA CATTCTTAGA CTGCTTTCCA AAACACCCCT TGTGTGTTTG GGTGACCTTC 10069
AGCAACTTCA CCCTGTCGGC TTTGATTCCT ACTGTTATGT GTTCGATCAG ATGCCTCAGA 10129
AGCAGCTGAC CACTATTTAC AGATTTGGCC CTAACATCTG CGCACGCATC CAGCCTTGTT 10189
ACAGGGAGAA ACTTGAATCT AAGGCTAGGA ACACTAGGGT GGTTTTTACC ACCCGGCCTG 10249
TGGCCTTTGG TCAGGTGCTG ACACCATACC ATAAAGATCG CATCGGCTCT GCGATAACCA 10309
TAGATTCATC CCAGGGGGCC ACCTTTGATA TTGTGACATT GCATCTACCA TCGCCAAAGT 10369
CCCTAAATAA ATCCCGAGCA CTTGTAGCCA TCACTCGGGC AAGACACGGG TTGTTCATTT 10429
ATGACCCTCA TAACCAGCTC CAGGAGTTTT TCAACTTAAC CCCTGAGCGC ACTGATTGTA 10489
ACCTTGTGTT CAGCCGTGGG GATGAGCTGG TAGTTCTGAA TGCGGATAAT GCAGTCACAA 10549
CTGTAGCGAA GGCCCTTGAG ACAGGTCCAT CTCGATTTCG AGTATCAGAC CCGAGGTGCA 10609
AGTCTCTCTT AGCCGCTTGT TCGGCCAGTC TGGAAGGGAG CTGTATGCCA CTACCGCAAG 10669
TGGCACATAA CCTGGGGTTT TACTTTTCCC CGGACAGTCC AACATTTGCA CCTCTGCCAA 10729
AAGAGTTGGC GCCACATTGG CCAGTGGTTA CCCACCAGAA TAATCGGGCG TGGCCTGATC 10789
GACTTGTCGC TAGTATGCGC CCAATTGATG CCCGCTACAG CAAGCCAATG GTCGGTGCAG 10849
GGTATGTGGT CGGGCCGTCC ACCTTTCTTG GTACTCCTGG TGTGGTGTCA TACTATCTCA 10909
CACTATACAT CAGGGGTGAG CCCCAGGCCT TGCCAGAAAC ACTCGTTTCA ACAGGGCGTA 10969
TAGCCACAGA TTGTCGGGAG TATCTCGACG CGGCTGAGGA AGAGGCAGCA AAAGAACTCC 11029
CCCACGCATT CATTGGCGAT GTCAAAGGTA CCACGGTTGG GGGGTGTCAT CACATTACAT 11089
CAAAATACCT ACCTAGGTCC CTGCCTAAGG ACTCTGTTGC CGTAGTTGGA GTAAGTTCGC 11149
CCGGCAGGGC TGCTAAAGCC GTGTGCACTC TCACCGATGT GTACCTCCCC GAACTCCGGC 11209
CATATCTGCA ACCTGAGACG GCATCAAAAT GCTGGAAACT CAAATTAGAC TTCAGGGACG 11269
TCCGACTAAT GGTCTGGAAA GGAGCCACCG CCTATTTCCA GTTGGAAGGG CTTACATGGT 11329
CGGCGCTGCC CGACTATGCC AGGTTYATTC AGCTGCCCAA GGATGCCGTT GTATACATTG 11389
ATCCGTGTAT AGGACCGGCA ACAGCCAACC GTAAGGTCGT GCGAACCACA GACTGGCGGG 11449
CCGACCTGGC AGTGACACCG TATGATTACG GTGCCCAGAA CATTTTGACA ACAGCCTGGT 11509
TCGAGGACCT CGGGCCGCAG TGGAAGATTT TGGGGTTGCA GCCCTTTAGG CGAGCATTTG 11569
GCTTTGAAAA CACTGAGGAT TGGGCAATCC TTGCACGCCG TATGAATGAC GGCAAGGACT 11629
ACACTGACTA TAACTGGAAC TGTGTTCGAG AACGCCCACA CGCCATCTAC GGGCGTGCTC 11689
GTGACCATAC GTATCATTTT GCCCCTGGCA CAGAATTGCA GGTAGAGCTA GGTAAACCCC 11749
GGCTGCCGCC TGGGCAAGTG CCG TGAATTCGGG GTGATGCAAT GGGGTCACTG 11802
TGGAGTAAAA TCAGCCAGCT GTTCGTGGAC GCCTTCACTG AGTTCCTTGT TAGTGTGGTT 11862
GATATTGYCA TTTTCCTTGC CATACTGTTT GGGTTCACCG TCGCAGGATG GTTACTGGTC 11922
TTTCTTCTCA GAGTGGTTTG CTCCGCGCTT CTCCGTTCGC GCTCTGCCAT TCACTCTCCC 11982
GAACTATCGA AGGTCCTATG AAGGCTTGTT GCCCAACTGC AGACCGGATG TCCCACAATT 12042
TGCAGTCAAG CACCCATTGG GYATGTTTTG GCACATGCGA GTTTCCCACT TGATTGATGA 12102
GRTGGTCTCT CGTCGCATTT ACCAGACCAT GGAACATTCA GGTCAAGCGG CCTGGAAGCA 12162
GGTGGTTGGT GAGGCCACTC TCACGAAGCT GTCAGGGCTC GATATAGTTA CTCATTTCCA 12222
ACACCTGGCC GCAGTGGAGG CGGATTCTTG CCGCTTTCTC AGCTCACGAC TCGTGATGCT 12282
AAAAAATCTT GCCGTTGGCA ATGTGAGCCT ACAGTACAAC ACCACGTTGG ACCGCGTTGA 12342
GCTCATCTTC CCCACGCCAG GTACGAGGCC CAAGTTGACC GATTTCAGAC AATGGCTCAT 12402
CAGTGTGCAC GCTTCCATTT TTTCCTCTGT GGCTTCATCT GTTACCTTGT TCATAGTGCT 12462
TTGGCTTCGA ATTCCAGCTC TACGCTATGT TTTTGGTTTC CATTGGCCCA CGGCAACACA 12522
TCATTCGAGC TGACCATCAA CTACACCATA TGCATGCCCT GTTCTACCAG TCAAGCGGCT 12582
CGCCAAAGGC TCGAGCCCGG TCGTAACATG TGGTGCAAAA TAGGGCATGA CAGGTGTGAG 12642
GAGCGTGACC ATGATGAGTT GTTAATGTCC ATCCCGTCCG GGTACGACAA CCTCAAACTT 12702
GAGGGTTATT ATGCTTGGCT GGCTTTTTTG TCCTTTTCCT ACGCGGCCCA ATTCCATCCG 12762
GAGTTGTTCG GGATAGGGAA TGTGTCGCGC GTCTTCGTGG ACAAGCGACA CCAGTTCATT 12822
TGTGCCGAGC ATGATGGACA CAATTCAACC GTATCTACCG GACACAACAT CTCCGCATTA 12882
TATGCGGCAT ATTACCACCA CCAAATAGAC GGGGGCAATT GGTTCCATTT GGAATGGCTG 12942
CGGCCACTCT TTTCTTCCTG GCTGGTGCTC AACATATCAT GGTTTCTGAG GCGTTCGCCT 13002
GTAAGCCCTG TTTCTCGACG CATCTATCAG ATATTGAGAC CAACACGACC GCGGCTGCCG 13062
GTTTCATGGT CCTTCAGGAC ATCAATTGTT TCCGACCTCA CGGGGTCTCA GCAGCGCAAG 13122
AGAAAATTTC CTTCGGAAAG TCGTCCCAAT GTCGTGAAGC CGTCGGTACT CCCCAGTACA 13182
TCACGA TAACGGCTAA CGTGACCGAC GAATCATACT TGTACAACGC GGACCTGCTG 13238
ATGCTTTCTG CGTGCCTTTT CTACGCCTCA GAAATGAGCG AGAAAGGCTT CAAAGTCATC 13298
TTTGGGAATG TCTCTGGCGT TGTTTCTGCT TGTGTCAATT TCACAGATTA TGTGGCCCAT 13358
GTGACCCAAC ATACCCAGCA GCATCATCTG GTAATTGATC ACATTCGGTT GCTGCATTTC 13418
CTGACACCAT CTGCAATGAG GTGGGCTACA ACCATTGCTT GTTTGTTCGC CATTCTCTTG 13478
GCAATA TGAGATGTTC TCACAAATTG GGGCGTTTCT TGACTCCGCA CTCTTGCTTC 13534
TGGTGGCTTT TTTTGCTGTG TACCGGCTTG TCCTGGTCCT TTGCCGATGG CAACGGCGAC 13594
AGCTCGACAT ACCAATACAT ATATAACTTG ACGATATGCG AGCTGAATGG GACCGACTGG 13654
TTGTCCAGCC ATTTTGGTTG GGCAGTCGAG ACCTTTGTGC TTTACCCGGT TGCCACTCAT 13714
ATCCTCTCAC TGGGTTTTCT CACAACAAGC CATTTTTTTG ACGCGCTCGG TCTCGGCGCT 13774
GTATCCACTG CAGGATTTGT TGGCGGGCGG TACGTACTCT GCAGCGTCTA CGGCGCTTGT 13834
GCTTTCGCAG CGTTCGTATG TTTTGTCATC CGTGCTGCTA AAAATTGCAT GGCCTGCCGC 13894
TATGCCCGTA CCCGGTTTAC CAACTTCATT GTGGACGACC GGGGGAGAGT TCATCGATGG 13954
AAGTCTCCAA TAGTGGTAGA AAAATTGGGC AAAGCCGAAG TCGATGGCAA CCTCGTCACC 14014
ATCAAACATG TCGTCCTCGA AGGGGTTAAA GCTCAACCCT TGACGAGGAC TTCGGCTGAG 14074
CAATGGGAGG CC TAGACGATTT TTGCAACGAT CCTATCGCCG CACAAAAGCT 14126
CGTGCTAGCC TTTAGCATCA CATACACACC TATAATGATA TACGCCCTTA AGGTGTCACG 14186
CGGCCGACTC CTGGGGCTGT TGCACATCCT AATATTTCTG AACTGTTCCT TTACATTCGG 14246
ATACATGACA TATGTGCATT TTCAATCCAC CAACCGTGTC GCACTTACCC TGGGGGCTGT 14306
TGTCGCCCTT CTGTGGGGTG TTTACAGCTT CACAGAGTCA TGGAAGTTTA TCACTTCCAG 14366
ATGCAGATTG TGTTGCCTTG GCCGGCGATA CATTCTGGCC CCTGCCCATC ACGTAGAAAG 14426
TGCTGCAGGT CTCCATTCAA TCTCAGCGTC TGGTAACCGA GCATACGCTG TGAGAAAGCC 14486
CGGACTAACA TCAGTGAACG GCACTCTAGT ACCAGGACTT CGGAGCCTCG TGCTGGGCGG 14546
CAAACGAGCT GTTAAACGAG GAGTGGTTAA CCTCGTCAAG TATGGCCGG TAAAAACCAG 14605
AGCCAGAAGA AAAAGAAAAG TACAGCTCCG ATGGGGAATG GCCAGCCAGT CAATCAACTG 14665
TGCCAGTTGC TGGGTGCAAT GATAAAGTCC CAGCGCCAGC AACCTAGGGG AGGACAGGCY 14725
AAAAAGAAAA AGCCTGAGAA GCCACATTTT CCCCTGGCTG CTGAAGATGA CATCCGGCAC 14785
CACCTCACCC AGACTGAACG CTCCCTCTGC TTGCAATCGA TCCAGACGGC TTTCAATCAA 14845
GGCGCAGGAA CTGCGTCRCT TTCATCCAGC GGGAAGGTCA GTTTTCAGGT TGAGTTTATG 14905
CTGCCGGTTG CTCATACAGT GCGCCTGATT CGCGTGACTT CTACATCCGC CAGTCAGGGT 14965
GCAAGT TAATTTGACA GTCAGGTGAA TGGCCGCGAT GGCGTGTGGC CTCTGAGTCA 15021
CCTATTCAAT TAGGGCGATC ACATGGGGGT CATACTTAAT TCAGGCAGGA ACCATGTGAC 15081
CGAAATTAAA AAAAAAAAAA AAAAAAA 15108
2396 amino acids
amino acid
linear
protein
2
Met Ser Gly Thr Phe Ser Arg Cys Met Cys Thr Pro Ala Ala Arg Val
1 5 10 15
Phe Trp Asn Ala Gly Gln Val Phe Cys Thr Arg Cys Leu Ser Ala Arg
20 25 30
Ser Leu Leu Ser Pro Glu Leu Gln Asp Thr Asp Leu Gly Ala Val Gly
35 40 45
Leu Phe Tyr Lys Pro Arg Asp Lys Leu His Trp Lys Val Pro Ile Gly
50 55 60
Ile Pro Gln Val Glu Cys Thr Pro Ser Gly Cys Cys Trp Leu Ser Ala
65 70 75 80
Val Phe Pro Leu Ala Arg Met Thr Ser Gly Asn His Asn Phe Leu Gln
85 90 95
Arg Leu Val Lys Val Ala Asp Val Leu Tyr Arg Asp Gly Cys Leu Ala
100 105 110
Pro Arg His Leu Arg Glu Leu Gln Val Tyr Glu Arg Gly Cys Asn Trp
115 120 125
Tyr Pro Ile Thr Gly Pro Val Pro Gly Met Gly Leu Phe Ala Asn Ser
130 135 140
Met His Val Ser Asp Gln Pro Phe Pro Gly Ala Thr His Val Leu Thr
145 150 155 160
Asn Ser Pro Leu Pro Gln Gln Ala Cys Arg Gln Pro Phe Cys Pro Phe
165 170 175
Glu Glu Ala His Ser Ser Val Tyr Arg Trp Lys Lys Phe Val Val Phe
180 185 190
Thr Asp Ser Ser Leu Asn Gly Arg Ser Arg Met Met Trp Thr Pro Glu
195 200 205
Ser Asp Asp Ser Ala Ala Leu Glu Val Leu Pro Pro Glu Leu Glu Arg
210 215 220
Gln Val Glu Ile Leu Ile Arg Ser Phe Pro Ala His His Pro Val Asp
225 230 235 240
Leu Ala Asp Trp Glu Leu Thr Glu Ser Pro Glu Asn Gly Phe Ser Phe
245 250 255
Asn Thr Ser His Ser Cys Gly His Leu Val Gln Asn Pro Asp Val Phe
260 265 270
Asp Gly Lys Cys Trp Leu Ser Cys Phe Leu Gly Gln Ser Val Glu Val
275 280 285
Arg Cys His Glu Glu His Leu Ala Asp Ala Phe Gly Tyr Gln Thr Lys
290 295 300
Trp Gly Val His Gly Lys Tyr Leu Gln Arg Arg Leu Gln Val Arg Gly
305 310 315 320
Ile Arg Ala Val Val Asp Pro Asp Gly Pro Ile His Val Glu Ala Leu
325 330 335
Ser Cys Pro Gln Ser Trp Ile Arg His Leu Thr Leu Asp Asp Asp Val
340 345 350
Thr Pro Gly Phe Val Arg Leu Thr Ser Leu Arg Ile Val Pro Asn Thr
355 360 365
Glu Pro Thr Thr Ser Arg Ile Phe Arg Phe Gly Ala His Lys Trp Tyr
370 375 380
Gly Ala Ala Gly Lys Arg Ala Arg Ala Lys Arg Ala Ala Lys Ser Glu
385 390 395 400
Lys Asp Ser Ala Pro Thr Pro Lys Val Ala Leu Pro Val Pro Thr Cys
405 410 415
Gly Ile Thr Thr Tyr Ser Pro Pro Thr Asp Gly Ser Cys Gly Trp His
420 425 430
Val Leu Ala Ala Ile Met Asn Arg Met Ile Asn Gly Asp Phe Thr Ser
435 440 445
Pro Leu Thr Gln Tyr Asn Arg Pro Glu Asp Asp Trp Ala Ser Asp Tyr
450 455 460
Asp Leu Val Gln Ala Ile Gln Cys Leu Arg Leu Pro Ala Thr Val Val
465 470 475 480
Arg Asn Arg Ala Cys Pro Asn Ala Lys Tyr Leu Ile Lys Leu Asn Gly
485 490 495
Val His Trp Glu Val Glu Val Arg Ser Gly Met Ala Pro Arg Ser Leu
500 505 510
Ser Arg Glu Cys Val Val Gly Val Cys Ser Glu Gly Cys Val Ala Pro
515 520 525
Pro Tyr Pro Ala Asp Gly Leu Pro Lys Arg Ala Leu Glu Ala Leu Ala
530 535 540
Ser Ala Tyr Arg Leu Pro Ser Asp Cys Val Ser Ser Gly Ile Ala Asp
545 550 555 560
Phe Leu Ala Asn Pro Pro Pro Gln Glu Phe Trp Thr Leu Asp Lys Met
565 570 575
Leu Thr Ser Pro Ser Pro Glu Arg Ser Gly Phe Ser Ser Leu Tyr Lys
580 585 590
Leu Leu Leu Glu Val Val Pro Gln Lys Cys Gly Ala Thr Glu Gly Ala
595 600 605
Phe Ile Tyr Ala Val Glu Arg Met Leu Lys Asp Cys Pro Ser Ser Lys
610 615 620
Gln Ala Met Ala Leu Leu Ala Lys Ile Lys Val Pro Ser Ser Lys Ala
625 630 635 640
Pro Ser Val Ser Leu Asp Glu Cys Phe Pro Thr Asp Val Leu Ala Asp
645 650 655
Phe Glu Pro Ala Ser Gln Glu Arg Pro Gln Ser Ser Gly Ala Ala Val
660 665 670
Val Leu Cys Ser Pro Asp Ala Lys Glu Phe Glu Glu Ala Ala Xaa Glu
675 680 685
Glu Val Gln Glu Ser Gly His Lys Ala Val His Ser Ala Leu Leu Ala
690 695 700
Glu Gly Pro Asn Asn Glu Gln Val Gln Val Val Ala Gly Glu Gln Leu
705 710 715 720
Lys Leu Gly Gly Cys Gly Leu Ala Val Gly Asn Ala His Glu Gly Ala
725 730 735
Leu Val Ser Ala Gly Leu Ile Asn Leu Val Gly Gly Asn Leu Ser Pro
740 745 750
Ser Asp Pro Met Lys Glu Asn Met Leu Asn Ser Arg Glu Asp Glu Pro
755 760 765
Leu Asp Leu Ser Gln Pro Ala Pro Ala Ser Thr Thr Thr Leu Val Arg
770 775 780
Glu Gln Thr Pro Asp Asn Pro Gly Ser Asp Ala Gly Ala Leu Pro Val
785 790 795 800
Thr Val Arg Glu Phe Val Pro Thr Gly Pro Ile Leu Cys His Val Glu
805 810 815
His Cys Gly Thr Glu Ser Gly Asp Ser Ser Ser Pro Leu Asp Leu Ser
820 825 830
Asp Ala Gln Thr Leu Asp Gln Pro Leu Asn Leu Ser Leu Ala Ala Trp
835 840 845
Pro Val Arg Ala Thr Ala Ser Asp Pro Gly Trp Val His Gly Arg Arg
850 855 860
Glu Pro Val Phe Val Lys Pro Arg Asn Ala Phe Ser Asp Gly Asp Ser
865 870 875 880
Ala Leu Gln Phe Gly Glu Leu Ser Glu Ser Ser Ser Val Ile Glu Phe
885 890 895
Asp Arg Thr Lys Asp Ala Pro Val Val Asp Ala Pro Val Asp Leu Thr
900 905 910
Thr Ser Asn Glu Ala Leu Ser Val Val Asp Pro Phe Glu Phe Ala Glu
915 920 925
Leu Lys Arg Pro Arg Phe Ser Ala Gln Ala Leu Ile Asp Arg Gly Gly
930 935 940
Pro Leu Ala Asp Val His Ala Lys Ile Lys Asn Arg Val Tyr Glu Gln
945 950 955 960
Cys Leu Gln Ala Cys Glu Pro Gly Ser Arg Ala Thr Pro Ala Thr Arg
965 970 975
Glu Trp Leu Asp Lys Met Trp Asp Arg Val Asp Met Lys Thr Trp Arg
980 985 990
Cys Thr Ser Gln Phe Gln Ala Gly Arg Ile Leu Ala Ser Leu Lys Phe
995 1000 1005
Leu Pro Asp Met Ile Gln Asp Thr Pro Pro Pro Val Pro Arg Lys Asn
1010 1015 1020
Arg Ala Ser Asp Asn Ala Gly Leu Lys Gln Leu Val Ala Gln Trp Asp
1025 1030 1035 1040
Arg Lys Leu Ser Val Thr Pro Pro Pro Lys Pro Val Gly Pro Val Leu
1045 1050 1055
Asp Gln Ile Val Pro Pro Pro Thr Asp Ile Gln Gln Glu Asp Val Thr
1060 1065 1070
Pro Ser Asp Gly Pro Pro His Ala Pro Asp Phe Pro Ser Arg Val Ser
1075 1080 1085
Thr Gly Gly Ser Trp Lys Gly Leu Met Leu Ser Gly Thr Arg Leu Ala
1090 1095 1100
Gly Ser Ile Ser Gln Arg Leu Met Thr Trp Val Phe Glu Val Phe Ser
1105 1110 1115 1120
His Leu Pro Ala Phe Met Leu Thr Leu Phe Ser Pro Arg Gly Ser Met
1125 1130 1135
Ala Pro Gly Asp Trp Leu Phe Ala Gly Val Val Leu Leu Ala Leu Leu
1140 1145 1150
Leu Cys Arg Ser Tyr Pro Ile Leu Gly Cys Leu Pro Leu Leu Gly Val
1155 1160 1165
Phe Ser Gly Ser Leu Arg Arg Val Arg Leu Gly Val Phe Gly Ser Trp
1170 1175 1180
Met Ala Phe Ala Val Phe Leu Phe Ser Thr Pro Ser Asn Pro Val Gly
1185 1190 1195 1200
Ser Ser Cys Asp His Asp Ser Pro Glu Cys His Ala Glu Leu Leu Ala
1205 1210 1215
Leu Glu Gln Arg Gln Leu Trp Glu Pro Val Arg Gly Leu Val Val Gly
1220 1225 1230
Pro Ser Gly Leu Leu Cys Val Ile Leu Gly Lys Leu Leu Gly Gly Ser
1235 1240 1245
Arg Tyr Leu Trp His Val Leu Leu Arg Leu Cys Met Leu Ala Asp Leu
1250 1255 1260
Ala Leu Ser Leu Val Tyr Val Val Ser Gln Gly Arg Cys His Lys Cys
1265 1270 1275 1280
Trp Gly Lys Cys Ile Arg Thr Ala Pro Ala Glu Val Ala Leu Asn Val
1285 1290 1295
Phe Pro Phe Ser Arg Ala Thr Arg Val Ser Leu Val Ser Leu Cys Asp
1300 1305 1310
Arg Phe Gln Thr Pro Lys Gly Val Asp Pro Val His Leu Ala Thr Gly
1315 1320 1325
Trp Arg Gly Cys Trp Arg Gly Glu Ser Pro Ile His Gln Pro His Gln
1330 1335 1340
Lys Pro Ile Ala Tyr Ala Asn Leu Asp Glu Lys Lys Met Ser Ala Gln
1345 1350 1355 1360
Thr Val Val Ala Val Pro Tyr Asp Pro Ser Gln Ala Ile Lys Cys Leu
1365 1370 1375
Lys Val Leu Gln Ala Gly Gly Ala Ile Val Asp Gln Pro Thr Pro Glu
1380 1385 1390
Val Val Arg Val Ser Glu Ile Pro Phe Ser Ala Pro Phe Phe Pro Lys
1395 1400 1405
Val Pro Val Asn Pro Asp Cys Arg Val Val Val Asp Ser Asp Thr Phe
1410 1415 1420
Val Ala Ala Val Arg Cys Gly Tyr Ser Thr Ala Gln Leu Xaa Leu Gly
1425 1430 1435 1440
Arg Gly Asn Phe Ala Lys Leu Asn Gln Thr Pro Pro Arg Asn Ser Ile
1445 1450 1455
Ser Thr Lys Thr Thr Gly Gly Ala Ser Tyr Thr Leu Ala Val Ala Gln
1460 1465 1470
Val Ser Ala Trp Thr Leu Val His Phe Ile Leu Gly Leu Trp Phe Thr
1475 1480 1485
Ser Pro Gln Val Cys Gly Arg Gly Thr Ala Asp Pro Trp Cys Ser Asn
1490 1495 1500
Pro Phe Ser Tyr Pro Thr Tyr Gly Pro Gly Val Val Cys Ser Ser Arg
1505 1510 1515 1520
Leu Cys Val Ser Ala Asp Gly Val Thr Leu Pro Leu Phe Ser Ala Val
1525 1530 1535
Ala Gln Leu Ser Gly Arg Glu Val Gly Ile Phe Ile Leu Val Leu Val
1540 1545 1550
Ser Leu Thr Ala Leu Ala His Arg Met Ala Leu Lys Ala Asp Met Leu
1555 1560 1565
Val Val Phe Ser Ala Phe Cys Ala Tyr Ala Trp Pro Met Ser Ser Trp
1570 1575 1580
Leu Ile Cys Phe Phe Pro Ile Leu Leu Lys Trp Val Thr Leu His Pro
1585 1590 1595 1600
Leu Thr Met Leu Trp Val His Ser Phe Leu Val Phe Cys Leu Pro Ala
1605 1610 1615
Ala Gly Ile Leu Ser Leu Gly Ile Thr Gly Leu Leu Trp Ala Ile Gly
1620 1625 1630
Arg Phe Thr Gln Val Ala Gly Ile Ile Thr Pro Tyr Asp Ile His Gln
1635 1640 1645
Tyr Thr Ser Gly Pro Arg Gly Ala Ala Ala Val Ala Thr Ala Pro Glu
1650 1655 1660
Gly Thr Tyr Met Ala Ala Val Arg Arg Ala Ala Leu Thr Gly Arg Thr
1665 1670 1675 1680
Leu Ile Phe Thr Pro Ser Ala Val Gly Ser Leu Leu Glu Gly Ala Phe
1685 1690 1695
Arg Thr His Lys Pro Cys Leu Asn Thr Val Asn Val Val Gly Ser Ser
1700 1705 1710
Leu Gly Ser Gly Gly Val Phe Thr Ile Asp Gly Arg Arg Thr Val Val
1715 1720 1725
Thr Ala Ala His Val Leu Asn Gly Asp Thr Ala Arg Val Thr Gly Asp
1730 1735 1740
Ser Tyr Asn Arg Met His Thr Phe Lys Thr Asn Gly Asp Tyr Ala Trp
1745 1750 1755 1760
Ser His Ala Asp Asp Trp Gln Gly Val Ala Pro Val Val Lys Val Ala
1765 1770 1775
Lys Gly Tyr Arg Gly Arg Ala Tyr Trp Gln Thr Ser Thr Gly Val Glu
1780 1785 1790
Pro Gly Ile Ile Gly Glu Gly Phe Ala Phe Cys Phe Thr Asn Cys Gly
1795 1800 1805
Asp Ser Gly Ser Pro Val Ile Ser Glu Ser Gly Asp Leu Ile Gly Ile
1810 1815 1820
His Thr Gly Ser Asn Lys Leu Gly Ser Gly Leu Val Thr Thr Pro Glu
1825 1830 1835 1840
Gly Glu Thr Cys Thr Ile Lys Glu Thr Lys Leu Ser Asp Leu Ser Arg
1845 1850 1855
His Phe Ala Gly Pro Ser Val Pro Leu Gly Asp Ile Lys Leu Ser Pro
1860 1865 1870
Ala Ile Ile Pro Asp Val Thr Ser Ile Pro Ser Asp Leu Ala Ser Leu
1875 1880 1885
Leu Ala Ser Val Pro Val Val Glu Gly Gly Leu Ser Thr Val Gln Leu
1890 1895 1900
Leu Cys Val Phe Phe Leu Leu Trp Arg Met Met Gly His Ala Trp Thr
1905 1910 1915 1920
Pro Ile Val Ala Val Gly Phe Phe Leu Leu Asn Glu Ile Leu Pro Ala
1925 1930 1935
Val Leu Val Arg Ala Val Phe Ser Phe Ala Leu Phe Val Leu Ala Trp
1940 1945 1950
Ala Thr Pro Trp Ser Ala Gln Val Leu Met Ile Arg Leu Leu Thr Ala
1955 1960 1965
Ser Leu Asn Arg Asn Lys Leu Ser Leu Ala Phe Tyr Ala Leu Gly Gly
1970 1975 1980
Val Val Gly Leu Ala Ala Glu Ile Gly Thr Phe Ala Gly Arg Leu Ser
1985 1990 1995 2000
Glu Leu Ser Gln Ala Leu Ser Thr Tyr Cys Phe Leu Pro Arg Val Leu
2005 2010 2015
Ala Met Thr Ser Cys Val Pro Thr Ile Ile Ile Gly Gly Leu His Thr
2020 2025 2030
Leu Gly Val Ile Leu Trp Xaa Phe Lys Tyr Arg Cys Leu His Asn Met
2035 2040 2045
Leu Val Gly Asp Gly Ser Phe Ser Ser Ala Phe Phe Leu Arg Tyr Phe
2050 2055 2060
Ala Glu Gly Asn Leu Arg Lys Gly Val Ser Gln Ser Cys Gly Met Asn
2065 2070 2075 2080
Asn Glu Ser Leu Thr Ala Ala Leu Ala Cys Lys Leu Ser Gln Ala Asp
2085 2090 2095
Leu Asp Phe Leu Ser Ser Leu Thr Asn Phe Lys Cys Phe Val Ser Ala
2100 2105 2110
Ser Asn Met Lys Asn Ala Ala Gly Gln Tyr Ile Glu Ala Ala Tyr Ala
2115 2120 2125
Lys Ala Leu Arg Gln Glu Leu Ala Ser Leu Val Gln Ile Asp Lys Met
2130 2135 2140
Lys Gly Val Leu Ser Lys Leu Glu Ala Phe Ala Glu Thr Ala Thr Pro
2145 2150 2155 2160
Ser Leu Asp Ile Gly Asp Val Ile Val Leu Leu Gly Gln His Pro His
2165 2170 2175
Gly Ser Ile Leu Asp Ile Asn Val Gly Thr Glu Arg Lys Thr Val Ser
2180 2185 2190
Val Gln Glu Thr Arg Ser Leu Gly Gly Ser Lys Phe Ser Val Cys Thr
2195 2200 2205
Val Val Ser Asn Thr Pro Val Asp Ala Xaa Thr Gly Ile Pro Leu Gln
2210 2215 2220
Thr Pro Thr Pro Leu Phe Glu Asn Gly Pro Arg His Arg Ser Glu Glu
2225 2230 2235 2240
Asp Asp Leu Lys Val Glu Arg Met Lys Lys His Cys Val Ser Leu Gly
2245 2250 2255
Phe His Asn Ile Asn Gly Lys Val Tyr Cys Lys Ile Trp Asp Lys Ser
2260 2265 2270
Thr Gly Asp Thr Phe Tyr Thr Asp Asp Ser Arg Tyr Thr Gln Asp His
2275 2280 2285
Ala Phe Gln Asp Arg Ser Ala Asp Tyr Arg Asp Arg Asp Tyr Glu Gly
2290 2295 2300
Val Gln Thr Thr Pro Gln Gln Gly Phe Asp Pro Lys Ser Glu Thr Pro
2305 2310 2315 2320
Val Gly Thr Val Val Ile Gly Gly Ile Thr Tyr Asn Arg Tyr Leu Ile
2325 2330 2335
Lys Gly Lys Glu Val Leu Val Pro Lys Pro Asp Asn Cys Leu Glu Ala
2340 2345 2350
Ala Lys Leu Ser Leu Glu Gln Ala Leu Ala Gly Met Gly Gln Thr Cys
2355 2360 2365
Asp Leu Thr Ala Ala Glu Val Glu Lys Leu Lys Arg Ile Ile Ser Gln
2370 2375 2380
Leu Gln Gly Leu Thr Thr Glu Gln Ala Leu Asn Cys
2385 2390 2395
1463 amino acids
amino acid
linear
protein
3
Thr Gly Phe Lys Leu Leu Ala Ala Ser Gly Leu Thr Arg Cys Gly Arg
1 5 10 15
Gly Gly Leu Val Val Thr Glu Thr Ala Val Lys Ile Ile Lys Tyr His
20 25 30
Ser Arg Thr Phe Thr Leu Gly Pro Leu Asp Leu Lys Val Thr Ser Glu
35 40 45
Val Glu Val Lys Lys Ser Thr Glu Gln Gly His Ala Val Val Ala Asn
50 55 60
Leu Cys Ser Gly Val Ile Leu Met Arg Pro His Pro Pro Ser Leu Val
65 70 75 80
Asp Val Leu Leu Lys Pro Gly Leu Asp Thr Ile Pro Gly Ile Gln Pro
85 90 95
Gly His Gly Ala Gly Asn Met Gly Val Asp Gly Ser Ile Trp Asp Phe
100 105 110
Glu Thr Ala Pro Thr Lys Ala Glu Leu Glu Leu Ser Lys Gln Ile Ile
115 120 125
Gln Ala Cys Glu Val Arg Arg Gly Asp Ala Pro Asn Leu Gln Leu Pro
130 135 140
Tyr Lys Leu Tyr Pro Val Arg Gly Asp Pro Glu Arg His Lys Gly Arg
145 150 155 160
Leu Ile Asn Thr Arg Phe Gly Asp Leu Pro Tyr Lys Thr Pro Gln Asp
165 170 175
Thr Lys Ser Ala Ile His Ala Ala Cys Cys Leu His Pro Asn Gly Ala
180 185 190
Pro Val Ser Asp Gly Lys Ser Thr Leu Gly Thr Thr Leu Gln His Gly
195 200 205
Phe Glu Leu Tyr Val Pro Thr Val Pro Tyr Ser Val Met Glu Tyr Leu
210 215 220
Asp Ser Arg Pro Asp Thr Pro Phe Met Cys Thr Lys His Gly Thr Ser
225 230 235 240
Lys Ala Ala Ala Glu Asp Leu Gln Lys Tyr Asp Leu Ser Thr Gln Gly
245 250 255
Phe Val Leu Pro Gly Val Leu Arg Leu Val Arg Arg Phe Ile Phe Gly
260 265 270
His Ile Gly Lys Ala Pro Pro Leu Phe Leu Pro Ser Thr Tyr Pro Ala
275 280 285
Lys Asn Ser Met Ala Gly Ile Asn Gly Gln Arg Phe Pro Thr Lys Asp
290 295 300
Val Gln Ser Ile Pro Glu Ile Asp Glu Met Cys Ala Arg Ala Val Lys
305 310 315 320
Glu Asn Trp Gln Thr Val Thr Pro Cys Thr Leu Lys Lys Gln Tyr Cys
325 330 335
Ser Lys Pro Lys Thr Arg Thr Ile Leu Gly Thr Asn Asn Phe Ile Ala
340 345 350
Leu Ala His Arg Ser Ala Leu Ser Gly Val Thr Gln Ala Phe Met Lys
355 360 365
Lys Ala Trp Lys Ser Pro Ile Ala Leu Gly Lys Asn Lys Phe Lys Glu
370 375 380
Leu His Cys Thr Val Ala Gly Arg Cys Leu Glu Ala Asp Leu Ala Ser
385 390 395 400
Cys Asp Arg Ser Thr Pro Ala Ile Val Arg Trp Phe Val Ala Asn Leu
405 410 415
Leu Tyr Glu Leu Ala Gly Cys Glu Glu Tyr Leu Pro Ser Tyr Val Leu
420 425 430
Asn Cys Cys His Asp Leu Val Ala Thr Gln Asp Gly Ala Phe Thr Lys
435 440 445
Arg Gly Gly Leu Ser Ser Gly Asp Pro Val Thr Ser Val Ser Asn Thr
450 455 460
Val Tyr Ser Leu Val Ile Tyr Ala Gln His Met Val Leu Ser Ala Leu
465 470 475 480
Lys Met Gly His Glu Ile Gly Leu Lys Phe Leu Glu Glu Gln Leu Lys
485 490 495
Phe Glu Asp Leu Leu Glu Ile Gln Pro Met Leu Val Tyr Ser Asp Asp
500 505 510
Leu Val Leu Tyr Ala Glu Arg Pro Xaa Phe Pro Asn Tyr His Trp Trp
515 520 525
Val Glu His Leu Asp Leu Met Leu Gly Phe Arg Thr Asp Pro Lys Lys
530 535 540
Thr Val Ile Thr Asp Lys Pro Ser Phe Leu Gly Cys Arg Ile Glu Ala
545 550 555 560
Gly Arg Gln Leu Val Pro Asn Arg Asp Arg Ile Leu Ala Ala Leu Ala
565 570 575
Tyr His Met Lys Ala Gln Asn Ala Ser Glu Tyr Tyr Ala Ser Ala Ala
580 585 590
Ala Ile Leu Met Asp Ser Cys Ala Cys Ile Asp His Asp Pro Glu Trp
595 600 605
Tyr Glu Asp Leu Ile Cys Gly Ile Ala Arg Cys Ala Arg Gln Asp Gly
610 615 620
Tyr Ser Phe Pro Gly Pro Ala Phe Phe Met Ser Met Trp Glu Lys Leu
625 630 635 640
Arg Ser His Asn Glu Gly Lys Lys Phe Arg His Cys Gly Ile Cys Asp
645 650 655
Ala Lys Ala Asp Tyr Ala Ser Ala Cys Gly Leu Asp Leu Cys Leu Phe
660 665 670
His Ser His Phe His Gln His Cys Xaa Val Thr Leu Ser Cys Gly His
675 680 685
His Ala Gly Ser Lys Glu Cys Ser Gln Cys Gln Ser Pro Val Gly Ala
690 695 700
Gly Arg Ser Pro Leu Asp Ala Val Leu Lys Gln Ile Pro Tyr Lys Pro
705 710 715 720
Pro Arg Thr Val Ile Met Lys Val Gly Asn Lys Thr Thr Ala Leu Asp
725 730 735
Pro Gly Arg Tyr Gln Ser Arg Arg Gly Leu Val Ala Val Lys Arg Gly
740 745 750
Ile Ala Gly Asn Glu Val Asp Leu Ser Asp Xaa Asp Tyr Gln Val Val
755 760 765
Pro Leu Leu Pro Thr Cys Lys Asp Ile Asn Met Val Lys Val Ala Cys
770 775 780
Asn Val Leu Leu Ser Lys Phe Ile Val Gly Pro Pro Gly Ser Gly Lys
785 790 795 800
Thr Thr Trp Leu Leu Ser Gln Val Gln Asp Asp Asp Val Ile Tyr Xaa
805 810 815
Pro Thr His Gln Thr Met Phe Asp Ile Val Ser Ala Leu Lys Val Cys
820 825 830
Arg Tyr Ser Ile Pro Gly Ala Ser Gly Leu Pro Phe Pro Pro Pro Ala
835 840 845
Arg Ser Gly Pro Trp Val Arg Leu Ile Ala Ser Gly His Val Pro Gly
850 855 860
Arg Val Ser Tyr Leu Asp Glu Ala Gly Tyr Cys Asn His Leu Asp Ile
865 870 875 880
Leu Arg Leu Leu Ser Lys Thr Pro Leu Val Cys Leu Gly Asp Leu Gln
885 890 895
Gln Leu His Pro Val Gly Phe Asp Ser Tyr Cys Tyr Val Phe Asp Gln
900 905 910
Met Pro Gln Lys Gln Leu Thr Thr Ile Tyr Arg Phe Gly Pro Asn Ile
915 920 925
Cys Ala Arg Ile Gln Pro Cys Tyr Arg Glu Lys Leu Glu Ser Lys Ala
930 935 940
Arg Asn Thr Arg Val Val Phe Thr Thr Arg Pro Val Ala Phe Gly Gln
945 950 955 960
Val Leu Thr Pro Tyr His Lys Asp Arg Ile Gly Ser Ala Ile Thr Ile
965 970 975
Asp Ser Ser Gln Gly Ala Thr Phe Asp Ile Val Thr Leu His Leu Pro
980 985 990
Ser Pro Lys Ser Leu Asn Lys Ser Arg Ala Leu Val Ala Ile Thr Arg
995 1000 1005
Ala Arg His Gly Leu Phe Ile Tyr Asp Pro His Asn Gln Leu Gln Glu
1010 1015 1020
Phe Phe Asn Leu Thr Pro Glu Arg Thr Asp Cys Asn Leu Val Phe Ser
1025 1030 1035 1040
Arg Gly Asp Glu Leu Val Val Leu Asn Ala Asp Asn Ala Val Thr Thr
1045 1050 1055
Val Ala Lys Ala Leu Glu Thr Gly Pro Ser Arg Phe Arg Val Ser Asp
1060 1065 1070
Pro Arg Cys Lys Ser Leu Leu Ala Ala Cys Ser Ala Ser Leu Glu Gly
1075 1080 1085
Ser Cys Met Pro Leu Pro Gln Val Ala His Asn Leu Gly Phe Tyr Phe
1090 1095 1100
Ser Pro Asp Ser Pro Thr Phe Ala Pro Leu Pro Lys Glu Leu Ala Pro
1105 1110 1115 1120
His Trp Pro Val Val Thr His Gln Asn Asn Arg Ala Trp Pro Asp Arg
1125 1130 1135
Leu Val Ala Ser Met Arg Pro Ile Asp Ala Arg Tyr Ser Lys Pro Met
1140 1145 1150
Val Gly Ala Gly Tyr Val Val Gly Pro Ser Thr Phe Leu Gly Thr Pro
1155 1160 1165
Gly Val Val Ser Tyr Tyr Leu Thr Leu Tyr Ile Arg Gly Glu Pro Gln
1170 1175 1180
Ala Leu Pro Glu Thr Leu Val Ser Thr Gly Arg Ile Ala Thr Asp Cys
1185 1190 1195 1200
Arg Glu Tyr Leu Asp Ala Ala Glu Glu Glu Ala Ala Lys Glu Leu Pro
1205 1210 1215
His Ala Phe Ile Gly Asp Val Lys Gly Thr Thr Val Gly Gly Cys His
1220 1225 1230
His Ile Thr Ser Lys Tyr Leu Pro Arg Ser Leu Pro Lys Asp Ser Val
1235 1240 1245
Ala Val Val Gly Val Ser Ser Pro Gly Arg Ala Ala Lys Ala Val Cys
1250 1255 1260
Thr Leu Thr Asp Val Tyr Leu Pro Glu Leu Arg Pro Tyr Leu Gln Pro
1265 1270 1275 1280
Glu Thr Ala Ser Lys Cys Trp Lys Leu Lys Leu Asp Phe Arg Asp Val
1285 1290 1295
Arg Leu Met Val Trp Lys Gly Ala Thr Ala Tyr Phe Gln Leu Glu Gly
1300 1305 1310
Leu Thr Trp Ser Ala Leu Pro Asp Tyr Ala Arg Xaa Ile Gln Leu Pro
1315 1320 1325
Lys Asp Ala Val Val Tyr Ile Asp Pro Cys Ile Gly Pro Ala Thr Ala
1330 1335 1340
Asn Arg Lys Val Val Arg Thr Thr Asp Trp Arg Ala Asp Leu Ala Val
1345 1350 1355 1360
Thr Pro Tyr Asp Tyr Gly Ala Gln Asn Ile Leu Thr Thr Ala Trp Phe
1365 1370 1375
Glu Asp Leu Gly Pro Gln Trp Lys Ile Leu Gly Leu Gln Pro Phe Arg
1380 1385 1390
Arg Ala Phe Gly Phe Glu Asn Thr Glu Asp Trp Ala Ile Leu Ala Arg
1395 1400 1405
Arg Met Asn Asp Gly Lys Asp Tyr Thr Asp Tyr Asn Trp Asn Cys Val
1410 1415 1420
Arg Glu Arg Pro His Ala Ile Tyr Gly Arg Ala Arg Asp His Thr Tyr
1425 1430 1435 1440
His Phe Ala Pro Gly Thr Glu Leu Gln Val Glu Leu Gly Lys Pro Arg
1445 1450 1455
Leu Pro Pro Gly Gln Val Pro
1460
249 amino acids
amino acid
linear
protein
4
Met Gln Trp Gly His Cys Gly Val Lys Ser Ala Ser Cys Ser Trp Thr
1 5 10 15
Pro Ser Leu Ser Ser Leu Leu Val Trp Leu Ile Leu Xaa Phe Ser Leu
20 25 30
Pro Tyr Cys Leu Gly Ser Pro Ser Gln Asp Gly Tyr Trp Ser Phe Phe
35 40 45
Ser Glu Trp Phe Ala Pro Arg Phe Ser Val Arg Ala Leu Pro Phe Thr
50 55 60
Leu Pro Asn Tyr Arg Arg Ser Tyr Glu Gly Leu Leu Pro Asn Cys Arg
65 70 75 80
Pro Asp Val Pro Gln Phe Ala Val Lys His Pro Leu Xaa Met Phe Trp
85 90 95
His Met Arg Val Ser His Leu Ile Asp Glu Xaa Val Ser Arg Arg Ile
100 105 110
Tyr Gln Thr Met Glu His Ser Gly Gln Ala Ala Trp Lys Gln Val Val
115 120 125
Gly Glu Ala Thr Leu Thr Lys Leu Ser Gly Leu Asp Ile Val Thr His
130 135 140
Phe Gln His Leu Ala Ala Val Glu Ala Asp Ser Cys Arg Phe Leu Ser
145 150 155 160
Ser Arg Leu Val Met Leu Lys Asn Leu Ala Val Gly Asn Val Ser Leu
165 170 175
Gln Tyr Asn Thr Thr Leu Asp Arg Val Glu Leu Ile Phe Pro Thr Pro
180 185 190
Gly Thr Arg Pro Lys Leu Thr Asp Phe Arg Gln Trp Leu Ile Ser Val
195 200 205
His Ala Ser Ile Phe Ser Ser Val Ala Ser Ser Val Thr Leu Phe Ile
210 215 220
Val Leu Trp Leu Arg Ile Pro Ala Leu Arg Tyr Val Phe Gly Phe His
225 230 235 240
Trp Pro Thr Ala Thr His His Ser Ser
245
265 amino acids
amino acid
linear
protein
5
Met Ala His Gln Cys Ala Arg Phe His Phe Phe Leu Cys Gly Phe Ile
1 5 10 15
Cys Tyr Leu Val His Ser Ala Leu Ala Ser Asn Ser Ser Ser Thr Leu
20 25 30
Cys Phe Trp Phe Pro Leu Ala His Gly Asn Thr Ser Phe Glu Leu Thr
35 40 45
Ile Asn Tyr Thr Ile Cys Met Pro Cys Ser Thr Ser Gln Ala Ala Arg
50 55 60
Gln Arg Leu Glu Pro Gly Arg Asn Met Trp Cys Lys Ile Gly His Asp
65 70 75 80
Arg Cys Glu Glu Arg Asp His Asp Glu Leu Leu Met Ser Ile Pro Ser
85 90 95
Gly Tyr Asp Asn Leu Lys Leu Glu Gly Tyr Tyr Ala Trp Leu Ala Phe
100 105 110
Leu Ser Phe Ser Tyr Ala Ala Gln Phe His Pro Glu Leu Phe Gly Ile
115 120 125
Gly Asn Val Ser Arg Val Phe Val Asp Lys Arg His Gln Phe Ile Cys
130 135 140
Ala Glu His Asp Gly His Asn Ser Thr Val Ser Thr Gly His Asn Ile
145 150 155 160
Ser Ala Leu Tyr Ala Ala Tyr Tyr His His Gln Ile Asp Gly Gly Asn
165 170 175
Trp Phe His Leu Glu Trp Leu Arg Pro Leu Phe Ser Ser Trp Leu Val
180 185 190
Leu Asn Ile Ser Trp Phe Leu Arg Arg Ser Pro Val Ser Pro Val Ser
195 200 205
Arg Arg Ile Tyr Gln Ile Leu Arg Pro Thr Arg Pro Arg Leu Pro Val
210 215 220
Ser Trp Ser Phe Arg Thr Ser Ile Val Ser Asp Leu Thr Gly Ser Gln
225 230 235 240
Gln Arg Lys Arg Lys Phe Pro Ser Glu Ser Arg Pro Asn Val Val Lys
245 250 255
Pro Ser Val Leu Pro Ser Thr Ser Arg
260 265
183 amino acids
amino acid
linear
protein
6
Met Ala Ala Ala Thr Leu Phe Phe Leu Ala Gly Ala Gln His Ile Met
1 5 10 15
Val Ser Glu Ala Phe Ala Cys Lys Pro Cys Phe Ser Thr His Leu Ser
20 25 30
Asp Ile Glu Thr Asn Thr Thr Ala Ala Ala Gly Phe Met Val Leu Gln
35 40 45
Asp Ile Asn Cys Phe Arg Pro His Gly Val Ser Ala Ala Gln Glu Lys
50 55 60
Ile Ser Phe Gly Lys Ser Ser Gln Cys Arg Glu Ala Val Gly Thr Pro
65 70 75 80
Gln Tyr Ile Thr Ile Thr Ala Asn Val Thr Asp Glu Ser Tyr Leu Tyr
85 90 95
Asn Ala Asp Leu Leu Met Leu Ser Ala Cys Leu Phe Tyr Ala Ser Glu
100 105 110
Met Ser Glu Lys Gly Phe Lys Val Ile Phe Gly Asn Val Ser Gly Val
115 120 125
Val Ser Ala Cys Val Asn Phe Thr Asp Tyr Val Ala His Val Thr Gln
130 135 140
His Thr Gln Gln His His Leu Val Ile Asp His Ile Arg Leu Leu His
145 150 155 160
Phe Leu Thr Pro Ser Ala Met Arg Trp Ala Thr Thr Ile Ala Cys Leu
165 170 175
Phe Ala Ile Leu Leu Ala Ile
180
201 amino acids
amino acid
linear
protein
7
Met Arg Cys Ser His Lys Leu Gly Arg Phe Leu Thr Pro His Ser Cys
1 5 10 15
Phe Trp Trp Leu Phe Leu Leu Cys Thr Gly Leu Ser Trp Ser Phe Ala
20 25 30
Asp Gly Asn Gly Asp Ser Ser Thr Tyr Gln Tyr Ile Tyr Asn Leu Thr
35 40 45
Ile Cys Glu Leu Asn Gly Thr Asp Trp Leu Ser Ser His Phe Gly Trp
50 55 60
Ala Val Glu Thr Phe Val Leu Tyr Pro Val Ala Thr His Ile Leu Ser
65 70 75 80
Leu Gly Phe Leu Thr Thr Ser His Phe Phe Asp Ala Leu Gly Leu Gly
85 90 95
Ala Val Ser Thr Ala Gly Phe Val Gly Gly Arg Tyr Val Leu Cys Ser
100 105 110
Val Tyr Gly Ala Cys Ala Phe Ala Ala Phe Val Cys Phe Val Ile Arg
115 120 125
Ala Ala Lys Asn Cys Met Ala Cys Arg Tyr Ala Arg Thr Arg Phe Thr
130 135 140
Asn Phe Ile Val Asp Asp Arg Gly Arg Val His Arg Trp Lys Ser Pro
145 150 155 160
Ile Val Val Glu Lys Leu Gly Lys Ala Glu Val Asp Gly Asn Leu Val
165 170 175
Thr Ile Lys His Val Val Leu Glu Gly Val Lys Ala Gln Pro Leu Thr
180 185 190
Arg Thr Ser Ala Glu Gln Trp Glu Ala
195 200
173 amino acids
amino acid
linear
protein
8
Met Gly Gly Leu Asp Asp Phe Cys Asn Asp Pro Ile Ala Ala Gln Lys
1 5 10 15
Leu Val Leu Ala Phe Ser Ile Thr Tyr Thr Pro Ile Met Ile Tyr Ala
20 25 30
Leu Lys Val Ser Arg Gly Arg Leu Leu Gly Leu Leu His Ile Leu Ile
35 40 45
Phe Leu Asn Cys Ser Phe Thr Phe Gly Tyr Met Thr Tyr Val His Phe
50 55 60
Gln Ser Thr Asn Arg Val Ala Leu Thr Leu Gly Ala Val Val Ala Leu
65 70 75 80
Leu Trp Gly Val Tyr Ser Phe Thr Glu Ser Trp Lys Phe Ile Thr Ser
85 90 95
Arg Cys Arg Leu Cys Cys Leu Gly Arg Arg Tyr Ile Leu Ala Pro Ala
100 105 110
His His Val Glu Ser Ala Ala Gly Leu His Ser Ile Ser Ala Ser Gly
115 120 125
Asn Arg Ala Tyr Ala Val Arg Lys Pro Gly Leu Thr Ser Val Asn Gly
130 135 140
Thr Leu Val Pro Gly Leu Arg Ser Leu Val Leu Gly Gly Lys Arg Ala
145 150 155 160
Val Lys Arg Gly Val Val Asn Leu Val Lys Tyr Gly Arg
165 170
128 amino acids
amino acid
linear
protein
9
Met Ala Gly Lys Asn Gln Ser Gln Lys Lys Lys Lys Ser Thr Ala Pro
1 5 10 15
Met Gly Asn Gly Gln Pro Val Asn Gln Leu Cys Gln Leu Leu Gly Ala
20 25 30
Met Ile Lys Ser Gln Arg Gln Gln Pro Arg Gly Gly Gln Xaa Lys Lys
35 40 45
Lys Lys Pro Glu Lys Pro His Phe Pro Leu Ala Ala Glu Asp Asp Ile
50 55 60
Arg His His Leu Thr Gln Thr Glu Arg Ser Leu Cys Leu Gln Ser Ile
65 70 75 80
Gln Thr Ala Phe Asn Gln Gly Ala Gly Thr Ala Xaa Leu Ser Ser Ser
85 90 95
Gly Lys Val Ser Phe Gln Val Glu Phe Met Leu Pro Val Ala His Thr
100 105 110
Val Arg Leu Ile Arg Val Thr Ser Thr Ser Ala Ser Gln Gly Ala Ser
115 120 125 | 4y
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This application claims the benefit of U.S. Provisional Application No. 60/199,674 filed on Apr. 21, 2000.
FIELD AND BACKGROUND OF THE INVENTION
This invention relates generally to a flexible packaging film construction that contains a biaxially oriented polyester film, an adhesive and a flexible polyamide-containing coextruded film. In addition, this invention relates to a package prepared from a biaxially oriented polyester film, an adhesive and a flexible polyamide-containing coextruded film.
It is common practice to package articles such as food products in multilayer films or laminates to protect the packaged product from abuse and exterior contamination. The multilayer films or laminates provide convenient and durable packages for transportation and ultimate sale to the end user.
It is usual to include printed indicia like decorations and text on packaging films. A desirable aspect of a printed package requires the printed image to repeat identically from one package to the next. This requires the printed image and the package dimensions to coincide exactly over many iterations. When this successfully occurs, the print is deemed to be in register. It is convenient to include a dimensionally stable film like biaxially oriented polyester in the construction of a printed package. Such a film resists elongation through the various manufacturing processes used to produce a film construction and finished package. This resistance to elongation greatly benefits registration control.
Certain package styles are created by a technique known as thermoforming. In this instance, the film is shaped into a cavity by softening the film via thermal exposure and drawing the softened film into a mold. This package style is commonly used to contain items like processed meat. Film constructions engineered to accommodate thermoforming do not often include biaxially oriented films. The resistance to elongation of biaxially oriented films makes them especially difficult to thermoform. Beyond the formation of very shallow cavities, thermoformed articles that include biaxially oriented films tend to encounter defects like holes and poor definition of shape. Still, there exists limited use of oriented films in end uses that require the formation of very shallow cavities. These applications profit from the ability to easily and repetitively print the films such that the indicia on the packages are in register. It is desirable to extend the use of biaxially oriented films to include the manufacture of register printed packages with deeper thermoformed cavities.
SUMMARY OF THE INVENTION
This invention offers an improvement in the thermoforming performance of a register printed packaging film. The thermoformability of our packaging film construction that includes a biaxially oriented polyester film is substantially improved by also including a flexible poly amide-containing coextruded film. Simultaneous with the thermoforming improvement, the film offers excellent control of print registration.
The flexible polyamide-containing coextruded film contains at least one semi-crystalline polyamide layer. That layer may include polyamides such as nylon 6, nylon 66, nylon 6,66, and the like. Additionally, it may be prepared from a blend of a semi-crystalline polyamide and an amorphous polyamide. The blend is 80 to 90% by weight of the semi-crystalline polyamide and 10 to 20 by weight of the amorphous polyamide. The coextruded film may also contain first and second flexible polyamide layers that are immediately separated by an oxygen barrier layer. The oxygen barrier layer is preferably comprised of an ethylene vinyl alcohol copolymer.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a cross-sectional view of a multilayer film assembly of the present invention consisting of a biaxially oriented polyester film layer, an ink layer, an adhesive layer and a sequence of layers formed from a flexible polyamide-containing coextrusion.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawing there is illustrated a multilayer film assembly that is suitable for the fabrication of a register printed, thermoformable package. A biaxially oriented polyester (OPET) layer 16 is printed with suitable ink 15 . An example of a preferred biaxially oriented polyester film is MYLAR® 75 P25T available from DuPont Teijin Films. A suitable ink is represented by the Color Converting Industries' trade name AXL®.
In a manufacturing operation separate from the printing step described immediately above, a multilayer coextruded film is prepared. A preferred multilayer film coextrusion has at its core an ethylene vinyl alcohol copolymer (EVOH) barrier layer 11 . An example of the barrier layer core is SOARNOL® ET supplied by Noltex. Disposed on either side of the barrier layer core are layers 10 a and 10 b comprised of a flexible polyamide. The flexible polyamide is preferably prepared from a blend of 85% by weight of a semicrystalline polyamide and 15% by weight of an amorphous polyamide. An example of a suitable semicrystalline polyamide is a nylon 6 polymer supplied by BASF known as ULTRAMID® B36. A suitable amorphous polyamide is nylon 616T, produced by DuPont as SELAR® PA 3426. Simultaneously extruded with the barrier core layer 11 and the flexible polyamide layers 10 a and 10 b are tie layers 12 a and 12 b and polyolefin layers 13 a and 13 b . Tie layers are used to join flexible polyamide layers 12 a and 12 b to polyolefin layers 13 a and 13 b . Appropriate tie layer materials include maleic anhydride-grafted polyolefins, wherein the grafted polyolefins include those based on ethylene vinyl acetate copolymer, polypropylene, low density polyethylene, high density polyethylene and ethylene alpha-olefin copolymers. A commercially available example of a suitable maleic anhydride-grafted polyolefin is supplied by Rohm and Haas as TYMOR®1 N05. In a preferred version, tie layers 12 a and 12 b are comprised of a blend of 20%
by weight of Rohm and Haas TYMOR®1 N05 and 80% by weight of an ethylene alpha-olefin copolymer. One such suitable ethylene alpha-olefin copolymer is ATTANE® 4201 supplied by the Dow Chemical Company. Joined to the tie layers 12 a and 12 b are polyolefin layers 13 a and 13 b . The polyolefin layers may be composed of polypropylene, low density polyethylene, high density polyethylene, ethylene alpha-olefin copolymers, ethylene ester copolymers like ethylene vinyl acetate copolymers or ethylene methyl acrylate copolymers, ethylene acid copolymers like ethylene acrylic acid copolymers or ethylene methacrylic acid copolymers, ionomers and the like. An example of suitable polyolefin layers 13 a and 13 b in this embodiment include those comprised of an ethylene alpha-olefin copolymer like Dow ATTANE® 4201 (ULDPE). Layers 13 a and 13 b are advantageously modified with an antiblocking agent, slip agents and a processing aid. In this example, a suitable antiblocking agent is supplied as a concentrate of 20% by weight diatomaceous earth in low density polyethylene by Ampacet as grade 10063. This concentrate is added to the Dow ATTANE® 4201 at 3.5% by weight. A suitable slip agent is supplied as a concentrate of 4% erucamide and 2* stearamide in low density polyethylene by Ampacet as grade 10061. This concentrate is added to the Dow ATTANE® 4201 at 2.0% by weight. A suitable processing aid is supplied as a concentrate of 3% of a copolymer of hexafluoropropylene and vinylidene fluoride in linear density polyethylene by Ampacet as grade 10562. This concentrate is added to the Dow ATTANE® 4201 at 0.3%.
Further, to produce the composition given by example in FIG. 1 , the printed biaxially oriented polyester film, layers 15 and 16 , are joined to the multilayer coextruded film, layers 13 b , 12 b , 10 b , 11 , 10 a , 12 a and 13 a by an adhesive layer 14 . An appropriate adhesive layer is produced from the combination of an isocyanate-terminated polyester and a polyol. The preferred joining technique is known in the art as dry bond adhesive lamination. An example of an appropriate adhesive is supplied by Rohm and Haas as ADCOTE® 522.
Although we have only illustrated the compositions of layers 13 a and 13 b as having additives, it is understood that all of the compositions for the various layers can have additives such as slip agents, processing aids, antiblocking agents, antistatic agents, colorants, etc. Also, even as the aforementioned example is an embodiment of the invention, it is important to understand that the intent of the invention is to combine a biaxially oriented film with a flexible polyamide-containing multilayer coextrusion. The important result of this combination is to substantially improve the thermoformability of a register-printed flexible packaging film. Various features of the invention have been particularly shown and described concerning the illustrated embodiment of the invention. However, it must be understood that this particular arrangement does not limit, but merely illustrates, and the invention is to be given its fullest interpretation within the terms of the appended claims. | 4y
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is the National Stage of International Application No. PCT/JP2009/060914, filed on Jun. 16, 2009, which claims the benefit of Japanese Patent Application No. 2008-161673, filed on Jun. 20, 2008, the entire contents of both of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an amorphous siliceous powder, a method for production thereof and a use thereof.
2. Related Art
With rising demand for environmental conservation in recent years, it has been desired to impart flame retardancy to semiconductor sealing materials used for sealing semiconductor elements without using harmful flame retardants such as antimony compounds and brominated epoxy resins which have considerable environmental impact, and impart heat resistance to lead-free solders containing no lead. Semiconductor sealing materials are mainly composed of epoxy resins, phenol resin curing agents, curing accelerators, inorganic fillers and the like, In order to satisfy the requirements described above, semiconductor sealing materials including epoxy resins and the phenol resins having structures with abundant aromatic rings, and which are high flame retardant and heat resistant, and high inorganic filler loading have been employed. Thus, viscosity of the semiconductor sealing material upon sealing tends to increase.
Meanwhile, in response to demand for smaller, lighter and more sophisticated electronic devices, rapid development has been seen in thinning of electronic components, reducing the diameter of and lengthening spans of gold wire, and increasing the density of wiring pitch in an internal structure of a semiconductor. When a semiconductor is sealed using a semiconductor sealing material having a high viscosity, problems result, such as gold wire is deformed and cut, the semiconductor element is inclined, and narrow spaces are not filled. Thus, there is demand for a semiconductor sealing material that is flame retardant and which has reduced viscosity to allow correct sealing and reduce improper molding.
To satisfy these demands, semiconductor sealing materials having a reduced viscosity and enhanced molding property have been obtained by improving the epoxy resin and the phenol resin curing agent used therein (Patent Documents 1 and 2). Improvements in curing accelerators have been achieved with a technique referred to as ‘making a latent state’, where a reactive substrate is protected using a component which inhibits a curing property for the purpose of raising a temperature when curing of the epoxy resin is initiated (Patent Documents 3 and 4). Improvements in inorganic fillers have been achieved with controlling the particle size distribution thereof, such that the viscosity of the sealing material, which contains an inorganic filler, does not increase even at high inorganic filler loading (Patent Documents 5 and 6). However, these sealing materials do not have sufficiently reduced viscosity and enhanced molding property, and thus, prior to the present invention, no semiconductor sealing material having a reduced viscosity upon sealing with high inorganic filler loading, and enhanced molding property was available.
[Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2007-231159 [Patent Document 2] Japanese Unexamined Patent Application, First Publication No. 2007-262385 [Patent Document 3] Japanese Unexamined Patent Application, First Publication No. 2006-225630 [Patent Document 4] Japanese Unexamined Patent Application, First Publication No. 2002-284859 [Patent Document 5] Japanese Unexamined Patent Application, First Publication No. 2005-239892 [Patent Document 6] WO2007/132771
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a resin composition, and particularly a semiconductor sealing material having a reduced viscosity upon sealing and a further enhanced molding property even with high loading of an inorganic filler, and to provide an amorphous siliceous powder that is suitable for preparation thereof.
In a first aspect of the present invention, provided is an amorphous siliceous powder comprising Si and Al in a combined content thereof in the powder is 99.5% by mass or more in terms of their oxides; a content of Al in a first portion of the powder, having a particle size range of 15 μm or more to less than 70 μm, is 100 to 30000 ppm in terms of its oxide; a content of Al in a second portion of the powder, having a particle size range of 3 μm or more to less than 15 μm, is 100 to 7000 ppm in terms of its oxide; and a content of Al in the powder including the entire particle size range is 100 to 25000 ppm in terms of its oxide. In the present invention, it is preferable that a ratio (A/B) of (A) the content of Al in the first portion of the powder to (B) the content of Al in the second portion of the powder, is 1.0 to 20. It is also preferable that the powder has a multimodal particle size distribution with at least two peaks in a frequency particle size distribution, in which a maximum frequency value of a first peak is located between a particle size range of 15 to 70 μm, a maximum frequency value of a second peak is located between a particle size range of 3 to 10 μm and an average particle diameter is 5 to 50 μm.
In a second aspect of the present invention, provided is a method for producing the amorphous siliceous powder of the first aspect of the present invention, the method including spraying from separate burners a first raw material siliceous powder having an average particle diameter of 15 to 70 μm and a content of Al of a first Al source material of 100 to 30000 ppm in terms of its oxide, and a second raw material siliceous powder having an average particle diameter of 3 to 10 μm and a content of Al of a second Al source material of 100 to 7000 ppm in terms of its oxide, into a high temperature flame formed from a flammable gas and a supporting gas.
In third aspect of the present invention, provided is a resin composition containing the amorphous siliceous powder of the first aspect of the present invention, and a resin. The resin used for the composition preferably comprises an epoxy resin. In a fourth aspect of the present invention, provided is a semiconductor sealing material including the composition.
According to the present invention, it is possible to provide a resin composition, in particular a semiconductor sealing material, which is excellent in fluidity, viscosity property and molding property. It is also possible to provide an amorphous siliceous powder suitable for preparing the composition.
DETAILED DESCRIPTION OF THE INVENTION
In the amorphous siliceous powder of the present invention, the content of Al in a first portion of the powder, having a particle size range of 15 μm or more to less than 70 μm, is 100 to 30000 ppm in terms of its oxide, the content of Al in a second portion of the powder, having a particle size range of 3 μm or more to less than 15 μm, is 100 to 7000 ppm in terms of its oxide, and the content of Al in the powder including the entire particle size range is 100 to 25000 ppm in terms of its oxide. By adjusting the content of Al in each particle size range and in the entire particle size range to the aforementioned range, it becomes possible to prepare a sealing material which is excellent in fluidity, viscosity property and molding property.
The effects of the present invention are obtained via the mechanism explained below. When a Si atom in a silica structure is replaced with an Al atom, such that —O—Si—O—Al—O—Si—O—, the site where replacement has occurred becomes a strong solid acid site due to a difference between the coordination number of Si and the coordination number of Al. An epoxy rein, a phenol resin curing agent and a curing accelerator in addition to an amorphous siliceous powder are used in a semiconductor sealing material. When a semiconductor sealing material is heated to a general thermal cure temperature (molding temperature) of about 150 to 200° C., a proton in the phenol resin curing agent is drawn out by the curing accelerator, an anion polymerization chain reaction of the epoxy resin with the phenol resin curing agent progresses and the sealing material is thermally cured. When the amorphous siliceous powder of the present invention is used, the proton coordinated at the solid acid site is released by heating. This proton then binds to an anion polymerization end, and the polymerization chain reaction is suspended. As a result, thermal cure reaction in the sealing material is delayed. That is, by the amorphous siliceous powder of the present invention, it becomes possible to delay the thermal cure reaction of the resin in the sealing material, and the sealing material which is excellent in fluidity and viscosity property upon molding can be prepared.
When the content of Al in the first portion of the amorphous siliceous powder, having a particle size range of 15 μm or more to less than 70 μm, is less than 100 ppm in terms of its oxide, an amount of the formed solid acid sites is reduced, and thus, the effect of delaying the thermal cure reaction of the resin becomes insufficient. Meanwhile, when the content of Al in the first portion exceeds 30000 ppm in terms of its oxide, the surfaces of the particles constituting the amorphous siliceous powder become almost completely covered with Al 2 O 3 . Thus, the amount of the formed solid acid sites is reduced, and the effect of delaying the thermal cure reaction of the resin becomes insufficient. The content of Al in the first portion having a particle size range of 15 μm or more to less than 70 μm, is preferably 500 to 20000 ppm and more preferably 1000 to 15000 ppm in terms of its oxide.
When the content of Al in the second portion of the amorphous siliceous powder, having a particle size range of 3 μm or more to less than 15 μm, is less than 100 ppm in terms of its oxide, the amount of the formed solid acid sites is reduced, and thus, the effect of delaying the thermal cure reaction of the resin becomes insufficient. Meanwhile, when the content of Al in the second portion exceeds 7000 ppm, the number of epoxy chains coordinated to the surfaces of the particles that constitute the amorphous siliceous powder is increased. Thus, a rolling resistance of the amorphous siliceous powder increases, and the fluidity and the viscosity property upon molding deteriorate. The epoxy chains are also coordinated to the surfaces of the particles that constitute the amorphous siliceous powder in the particle size range of 15 μm or more to less than 70 μm, but the mass of each particle is large, and thus an influence of the rolling resistance due to the coordination of the epoxy chains is negligible. On the contrary, in the particle size range of 3 μm or more to less than 15 μm, the mass of the particle is small, and thus the influence of the rolling resistance due to the coordination of the epoxy chains is large. That is, it is important that the content of Al in the second portion having a particle size range of 3 μm or more to less than 15 μm, is 100 to 7000 ppm in terms of its oxide so that the effect of delaying the thermal cure reaction of the resin due to solid acid formation is exhibited more largely than the influence of the increased rolling resistance due to the coordination of the epoxy chains. The content of Al in the second portion having a particle size range of 3 μm or more to less than 15 μm, is preferably 200 to 5000 ppm and more preferably 350 to 3000 ppm in terms of its oxide.
When the content of Al in the amorphous siliceous powder is less than 100 ppm in terms of its oxide, the amount of the formed solid acid sites is reduced, and thus, the effect of delaying the thermal cure reaction of the resin becomes insufficient. When the content of Al in the amorphous siliceous powder exceeds 25000 ppm, the viscosity increase at high filler loading in the resin and the like, and the fluidity and the molding property deteriorates. Further, a kneader and a roll used when mixing the resin and a die used when molding undergo sever wear. The content of Al in the amorphous siliceous powder is preferably 300 to 18000 ppm and more preferably 500 to 12000 ppm.
In the amorphous siliceous powder of the present invention, a combined content of Si and Al in terms of their oxides is 99.5% by mass or more. When the content of Si and Al in terms of their oxides is less than 99.5% by mass, i.e., the content of components other than SiO 2 and Al 2 O 3 exceeds 0.5% by mass, unnecessary substances which are impurities are increased when the semiconductor sealing material is made. Thus, this is not preferable. For example, a part of the impurities may convert to their ionic form, which is then potentially eluted to harmfully affect the molding property. The content of Si and Al in terms of their oxides is preferably 99.6% by mass or more and more preferably 99.7% by mass or more.
The content of Si and Al in terms of their oxides in the amorphous siliceous powder of the present invention can be measured, for example, by a fluorescent X ray analysis method. That is, 5 g of lithium tetraborate and 30 μL of a release agent (aqueous solution of 50% lithium bromide) are added to 1 g of the amorphous siliceous powder, which is then melted at 1100° C. for 20 minutes to prepare glass beads. Measured is then performed using a fluorescent X ray apparatus (e.g., “Primus 2” supplied from Rigaku Denki Kogyo Co., Ltd.), and each content was quantified using a standard curve prepared from standard samples of SiO 2 or Al 2 O 3 . The measurement was performed by using an X ray tube made of Rhodium (Rh), and an irradiation diameter of 30 mm and an output power of 3.0 kW. When the content of Al in each portion of different particle size range was measured, the portions of the amorphous siliceous powder having a particle size range of 15 μm or more to less than 70 μm, and a particle size range of 3 μm or more to less than 15 μm, were collected by combining sieving using a sieve having an opening size of 70 μm and a sieve having an opening size of 15 μm and filtration using a membrane filter having a pore size of 3 μm, and the powder in each particle size range was quantified.
In the amorphous siliceous powder of the present invention, it is more preferable that the ratio (A/B) of (A) the content of Al in the first portion of the amorphous siliceous powder, having a particle size range of 15 μm or more to less than 70 μm, to (B) the content of Al in the second portion of the amorphous siliceous powder, having a particle size range of 3 μm or more to less than 15 μm, is 1.0 to 20. When the ratio (A/B) is less than 1.0, the content of Al in the second portion having a particle size range of 3 μm or more to less than 15 μm, is higher than the content of Al in the first portion having a particle size range of 15 μm or more to less than 70 μm. In this case, the influence of the increased rolling resistance due to the coordination of the epoxy chains of the particles in the particle size range of 3 μm or more to less than 15 μm described above becomes remarkable. Thus, this is not preferable. When the ratio (A/B) exceeds 20, the content of Al in the first portion having a particle size range of 15 μm or more to less than 70 μm, is more than 20 times higher than the content of Al in the second portion having the particle size range of 3 μm or more to less than 15 μm. Due to segregation of the solid acid sites in each particle size range, dispersibility of the amorphous siliceous powder deteriorates and the molding property thereof potentially deteriorates when making the semiconductor sealing material. Thus, this is not preferable. The ratio (A/B) is preferably 1.5 to 17 and more preferably 2.0 to 15.
It is more preferable that the amorphous siliceous powder of the present invention has a multimodal particle size distribution having at least two peaks in the frequency particle size distribution. That is, it is preferable that the particle size distribution is a multimodal particle size distribution having at least two peaks, the maximum frequency value of the first peak is located between a particle size range of 15 to 70 μm and the maximum frequency value of the second peak is located between a particle size range of 3 to 10 μm, when the particle sizes are measured using a laser diffraction scattering particle size distribution analyzer (“model LS-230” supplied from Beckman Coulter). This makes it easy to form a densely filled structure of the amorphous siliceous powder and makes it easier to enhance the fluidity and the viscosity property upon molding. The amorphous siliceous powder of the present invention preferably has an average particle diameter of 5 to 50 μm. When the average particle diameter is less than 5 μm, the molding property deteriorates. Thus, this is not preferable. Meanwhile, when the average particle diameter exceeds 50 μm, damage to semiconductor chips, severing of wires, clogging of die gates and the like are likely to result. The preferable average particle diameter is 8 to 40 μm and more preferably 10 to 35 μm. A maximum particle diameter is preferably 213 μm or less and more preferably 134 μm or less.
A sample for measuring a laser diffraction scattering particle size distribution was prepared by using water as a medium, adjusting a PIDS (polarization intensity differential scattering) concentration to 45 to 55% by mass and subjecting to an ultrasonic homogenizer with an output power of 200 W for one minute. The particle size distribution was analyzed by dividing into 116 in the range of 0.04 to 2000 μm using a particle diameter channel of log (μm)=0.04 width. A refractive index of 1.33 was used for water, and a refractive index of 1.46 was used for the amorphous siliceous powder. The particle diameter corresponding to a cumulative mass of 50% is the average particle diameter, and the particle diameter corresponding to a cumulative mass of 100% is the maximum particle diameter in the measured particle size distribution.
It is preferable that an amorphous rate measured by the following method is 95% or more in the amorphous siliceous powder of the present invention. The amorphous rate was determined by using a powder X ray diffraction apparatus (e.g., a brand name “Model Mini Flex” supplied from RIGAKU), performing an X ray diffraction analysis in the range of CuKα ray where 2θ was 26 to 27.5° and calculating from an intensity ratio of certain diffraction peaks. In the case of siliceous powder, crystal silica has a major peak at 26.7°, but amorphous silica has no peak. When the amorphous silica and the crystal silica are present as a mixture, a peak height at 26.7° depending on the ratio of crystal silica is obtained. Thus, a mixed ratio of the crystal silica is calculated from the ratio of the X ray intensity of the sample to the X ray intensity of a crystal silica standard sample (X ray diffraction intensity of sample/X ray diffraction intensity of crystal silica). Then, the amorphous rate is calculated from a formula, Amorphous rate (%)=(1−Mixed ratio of crystal silica)×100.
An average sphericity of the amorphous siliceous powder of the present invention is preferably 0.80 or more. This makes it possible to reduce the rolling resistance of the semiconductor sealing material to enhance the fluidity and the molding property. For obtaining the average sphericity, a particle image photographed using a stereoscopic microscope (e.g., the brand name of “Model SMZ-10 type” supplied from Nikon Corporation) is loaded in an image analyzer (e.g., the brand name of “MacView” supplied from Mountec), and a projected area (A) and a perimeter (PM) of the particle are measured on the photograph. When an area of a perfect circle corresponding to the perimeter (PM) is (B), a sphericity of that particle is (A)/(B). Thus, when the perfect circle having the same boundary length as the perimeter (PM) of the sample is assumed, B=π×(PM/2π) 2 is derived since PM=2πr and B=πr 2 . Thus, the sphericity of the individual particle is Sphericity=A/B=A×4π/(PM) 2 . The sphericity of 200 particles randomly obtained in this way was calculated, and their mean was squared to obtain the average sphericity. Another example of a method for obtaining sphericity is a conversion based upon an equation Sphericity=Circularity 2 , using circularity of an individual particle that is automatically measured quantitatively using a particle image analyzer (e.g., the brand name of “Model FPIA-3000” supplied from Sysmex).
Subsequently, the method of producing the amorphous siliceous powder of the present invention will be described. The method for producing the amorphous siliceous powder of the present invention includes the step of spraying from separate burners a first raw material siliceous powder having an average particle diameter of 15 to 70 μm and a content of Al of a first Al source material of 100 to 30000 ppm in terms of its oxide, and a second raw material siliceous powder having an average particle diameter of 3 to 10 μm and a content of Al of a second Al source material of 100 to 7000 ppm in terms of its oxide, into a high temperature flame formed from a flammable gas and a supporting gas. The average particle diameter of the amorphous siliceous powder obtained by the method of the present invention and the content of Al of the Al source material in the powder are almost the same as the average particle diameter and the Al content in the raw material siliceous powder, respectively. Thus, if the average particle diameter of the raw material siliceous powder and the content of Al of the Al source material in the powder depart from the aforementioned ranges, it becomes difficult to produce the amorphous siliceous powder of the present invention. Even when the first and second raw material siliceous powders respectively having an average particle diameter of 15 to 70 μm and 3 to 10 μm includes the Al source material in the aforementioned Al content, if they are sprayed from the same burner, it becomes difficult due to the diffusion of the Al source material to satisfy the requirement of the amorphous siliceous powder of the present invention where the content of Al in the first portion of the amorphous siliceous powder, having a particle size range of 15 μm or more to less than 70 μm, is 100 to 30000 ppm in terms of its oxide and the content of Al in the second portion of the amorphous siliceous powder, having a particle size range of 3 μm or more to less than 15 μm, is 100 to 7000 ppm in terms of its oxide.
Powders of minerals containing silica naturally produced such as high purity silica rock, high purity silica sand, quartz and berg crystal, and high purity silica powders produced by synthesis method such as precipitation silica and silica gel can be used for the raw material siliceous powder, but the silica rock powder is the most preferable in consideration of cost and availability. The silica rock powders having various particle diameters obtained by being pulverized by a pulverizer such as a vibrating mill or a ball mill are commercially available, and the silica rock powder having the desired average particle diameter could be selected appropriately.
In the present invention, it is preferable that the Al source material is aluminium oxide powder. The Al source material includes aluminium oxide, aluminium hydroxide, aluminium sulfate, aluminium chloride and aluminium organic compounds, but aluminium oxide is the most preferable because it has a melting point close to that of the raw material siliceous powder, thus it is easily fusion-bonded to the surface of the raw material siliceous powder when sprayed from the burner and an impurity content is low. The average particle diameter of the aluminium oxide powder is preferably 0.01 to 10 μm. When the average particle diameter is less than 0.01 μm, the powder is easily aggregated and a composition tends to become heterogeneous when fusion-bonded with the siliceous powder. Likewise when it exceeds 10 μm, the composition also becomes heterogeneous when fusion-bonded with the siliceous powder. The range of the average particle diameter is preferably 0.03 to 8 μm and more preferably 0.05 to 5 μm.
As an apparatus in which the raw material siliceous powder including the Al source material is sprayed into the high temperature flame formed from the flammable gas and the supporting gas, for example, one in which a trapping device is connected to a furnace casing comprising the burner is used. The furnace casing may be any of an open type or a closed type, or a vertical type or a horizontal type. The trapping device is provided with one or more of a gravity-setting chamber, a cyclone, a bag filter and an electric dust collector. The produced amorphous siliceous powder can be trapped by controlling its trapping condition. By way of example, Japanese Unexamined Patent Application, First Publication No. H11-57451 and Japanese Unexamined Patent Application, First Publication No. H11-71107 are included.
The resin composition of the present invention contains the amorphous siliceous powder of the present invention and a resin. The content of the amorphous siliceous powder in the resin composition is 10 to 95% by mass and more preferably 30 to 90% by mass.
As the resin, it is possible to use epoxy resins, silicone resins, phenol resins, melamine resins, unsaturated polyester, fluorine resins, polyamide such as polyimide, polyamideimide and polyether imide, polyester such as polybutylene terephthalate and polyethylene terephthalate, polyphenylene sulfide, aromatic polyester, polysulfone, liquid crystal polymers, polyether sulfone, polycarbonate, maleimide-modified resins, ABS resins, AAS (acrylonitrile-acryl rubber styrene) resins and AES (acrylonitrile ethylene propylene diene rubber-styrene) resins.
Among them, an epoxy resin having two or more epoxy groups in one molecule is preferable for formulating the semiconductor sealing material. Examples thereof include phenol novolak type epoxy resins, ortho cresol novolak type epoxy resins, those obtained by epoxidizing novolak resins from phenols and aldehydes, glycidyl ether such as bisphenol A, bisphenol F and bisphenol S, glycidyl ester acid epoxy resins obtained by reacting polybasic acid such as phthalic acid or dimer acid with epochlorohydrin, linear aliphatic epoxy resins, alicyclic epoxy resins, heterocyclic epoxy resins, alkyl-modified polyfunctional epoxy resins, β-naphthol novolak type epoxy resins, 1,6-dihydroxynaphthalene type epoxy resins, 2,7-dihydroxynaphthalene type epoxy resins, bishydroxybiphenyl type epoxy resins, and further epoxy resins in which halogen such as bromine is introduced for imparting the flame retardancy. Among them, the ortho cresol novolak type epoxy resin, the bishydroxybiphenyl type epoxy resin and the epoxy resin having a naphthalene skeleton are suitable in terms of moisture resistance and solder reflow resistance.
The resin composition of the present invention includes the curing agent for the epoxy resin, or the curing agent for the epoxy resin and the curing accelerator for the epoxy resin. The curing agent for the epoxy resin can include novolak type resins obtained by reacting one or a mixture of two or more selected from a group of phenol, cresol, xylenol, resorcinol, chlorophenol, t-butylphenol, nonylphenol, isopropylphenol and octylphenol with formaldehyde, paraformaldehyde or paraxylene in the presence of an oxidation catalyst, polyparahydroxystyrene resins, bisphenol compounds such as bisphenol A and bisphenol S, trifunctional phenols such as pyrogallol and phloroglucinol, acid anhydride such as maleic anhydride, phthalic anhydride and pyromellitic anhydride, and aromatic amine such as methaphenylenediamine, diaminodiphenylmethane and diaminodiphenylsulfone. The curing accelerator, e.g., triphenylphosphine, benzyldimethylamine or 2-methylimidazole described above can be used in order to accelerate the reaction of the epoxy resin with the curing agent.
The following components can further be combined if necessary in the resin composition of the present invention. That is, as a stress relaxation agent, rubber-like materials such as silicone rubbers, polysulfide rubbers, acrylic rubbers, butadiene-based rubbers, styrene-based block copolymers and saturated elastomers, various thermoplastic resins, resin-like materials such as silicone resins, and further epoxy resins and phenol resins partially or entirely modified with amino silicone, epoxy silicone or alkoxy silicone can be combined. As a silane coupling agent, epoxy silane such as γ-glycidoxypropyl trimethoxysilane and β-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, amino silane such as aminopropyl triethoxysilane, ureidopropyl triethoxysilane and N-phenylaminopropyl trimethoxysilane, hydrophobic silane compounds such as phenyl trimethoxysilane, methyl trimethoxysilane and octadecyl trimethoxysilane, and mercaptosilane can be combined. As a surface treating agent, Zr chelate, titanate coupling agents and aluminium-based coupling agents can be combined. As a flame retardant aid, Sb 2 O 3 , Sb 2 O 4 and Sb 2 O 5 can be combined. As a flame retardant, halogenated epoxy resins and phosphorous compounds can be combined. Carbon black, iron oxide, dyes and pigments can be combined as a coloring agent. Further, natural waxes, synthetic waxes, metal salts of straight fatty acids, acid amides, esters and paraffin can be combined as a mold releasing agent.
The resin composition of the present invention can be produced by blending the above materials in predetermined amounts using a blender or Henschel mixer, subsequently kneading them using a heat roll, a kneader, a uniaxial or biaxial extruder, cooling them and then pulverizing them.
The semiconductor sealing material of the present invention is obtained by containing the epoxy resin in the resin composition, and is composed of the composition including the curing agent for the epoxy resin and the curing accelerator for the epoxy resin. A common practice such as a transfer molding method or a vacuum print molding method is employed to seal the semiconductor using the semiconductor sealing material of the present invention.
EXAMPLES
Examples 1 to 28 and Comparative Examples 1 to 12
Various amorphous siliceous powders were produced by preparing various raw material siliceous powders (silica rock powders) having a different particle diameter, adding various Al source materials in various amounts, mixing them, subsequently spraying the raw material siliceous powder having the average particle diameter of 10 to 72 μm (raw material 1) from one burner and spraying the raw material siliceous powder having the average particle diameter of 2 to 16 μm (raw material 2) from the other burner using an apparatus in which two burners is disposed in an apparatus described in Japanese Unexamined Patent Application, First Publication No. H11-57451, then melting them in a flame and giving a spherodization treatment to them. In the amorphous siliceous powder, the content of Al in the first portion having a particle size range of 15 μm or more to less than 70 μm, the content of Al in the second portion having the particle size range of 3 μm or more to less than 15 μm, and the content of Al in the amorphous siliceous powder, were controlled by controlling the amount of the Al source material to be added in the raw material siliceous powder in each particle size range and the amount of the raw material siliceous powder having various average particle diameter to be supplied in the flame. The average particle diameter and the particle size distribution of the amorphous siliceous powder were controlled by controlling the average particle diameter and the amount of each raw material siliceous powder to be supplied in the flame. The average sphericity and the amorphous rate were controlled by controlling the amount of the raw material siliceous powder to be supplied in the flame and a flame temperature. LPG and oxygen gas were used for forming the flame, and the oxygen gas is also used as a carrier gas for feeding the raw material powder to the burner. Those conditions and characteristics of the obtained amorphous siliceous powders are shown in Tables 1 to 6.
The amorphous rate of any of the obtained amorphous siliceous powders was 99% or more, and the average sphericity thereof was 0.80 or more. In order to evaluate the characteristics of these amorphous siliceous powders as a filler of the semiconductor sealing material, the components in combination rates shown in Tables 1 to 6 were combined, dry-blended using the Henschel mixer, and subsequently heated and kneaded using a same direction engaged biaxial extrusion kneader (screw diameter D=25 mm, L/D=10.2, paddle rotation frequency: 50 to 120 rpm, discharged amount: 3.0 kg/hr, temperature of kneaded product: 98 to 100° C.). The kneaded product (discharged product) was pressed using a pressing machine, then cooled and subsequently pulverized to produce the semiconductor sealing material. Viscosity property (curelastometer torque), molding property (wire transformation ratio) and fluidity (spiral flow) thereof were evaluated according to the following. Their results are shown in Tables 1 to 3. The epoxy resin 1: biphenyl aralkyl type epoxy resin (NC-3000P supplied from Nippon Kayaku Co., Ltd.) and the epoxy resin 2: biphenyl type epoxy resin (YX-4000H supplied from Japan Epoxy Resin Co., Ltd.) were used as the epoxy resin. The phenol resin 1: biphenyl aralkyl resin (MEH-7851SS supplied from Nippon Kayaku Co., Ltd.) and the phenol resin 2: phenol aralkyl resin (MILEX XLC-4L supplied from Mitsui Chemicals Inc.) were used as the phenol resin. The coupling agent 1: epoxy silane (KBM-403 supplied from Shin-Etsu Chemical Co., Ltd.) and the coupling agent 2: phenylaminosilane (KBM-573 supplied from Shin-Etsu Chemical Co., Ltd.) were used as the coupling agent. The curing accelerator 1: triphenylphosphine (TPP supplied from Hokko Chemical Industry Co., Ltd.) and the curing accelerator 2: tetraphenyl phosphonium tetraphenyl borate (TPP-K supplied from Hokko Chemical Industry Co., Ltd.) were used as the curing accelerator. Carnauba wax (supplied from Clariant) was used as the mold releasing agent.
(1) Viscosity Property (Curelastometer Torque)
The viscosity property of the semiconductor sealing material obtained above was determined as follows. A torque 30 seconds after heating the semiconductor sealing material to 110° C. was a viscosity index using a curelastometer (e.g., a brand name “Curelastometer Model 3P-S type” supplied from JSR Trading Co., Ltd.). A smaller value of the torque indicates a better viscosity property.
(2) Molding Property (Wire Transformation Ratio)
The molding property of the semiconductor sealing material obtained above was determined as follows. Two mock semiconductor elements having a size of 8 mm×8 mm×0.3 mm were overlapped via a die attach film on a substrate for BGA, connected with a gold wire, and subsequently molded into a package size of 38 mm×38 mm×1.0 mm using each semiconductor sealing material and a transfer molding machine. The molded product was cured at 175° C. for 8 hours to produce a BGA type semiconductor. A portion of the gold wire in the semiconductor was observed using a soft X ray transmission apparatus, and the transformation ratio of the gold wire was determined. The transformation ratio of the gold wire was obtained by measuring the shortest distance X of the wire before sealing and the maximum change amount Y of the wire after sealing and calculating (Y/X)×100(%). This value was obtained as the mean of the transformation ratios of 12 gold wires. In the gold wire, its diameter is 30 μm and an average length is 5 mm. In the transfer molding condition, a die temperature was 175° C., a molding pressure was 7.4 MPa and a pressure preservation time was 90 seconds. The smaller the value, the smaller the transformation amount of the wire and the better the molding property.
(3) Fluidity (Spiral Flow)
A spiral flow value of each semiconductor sealing material was measured using a transfer molding machine provided with a die for measuring the spiral flow in accordance with EMMI-I-66 (Epoxy Molding Material Institute; Society of Plastic Industry). In the transfer molding condition, the die temperature was 175° C., the molding pressure was 7.4 MPa and the pressure preservation time was 120 seconds. The larger the value, the better the fluidity.
TABLE 1
Item
Example 1
Example 2
Example 3
Example 4
Example 5
Example 6
Example 7
Raw material
Type of Al source material
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
siliceous powder
Average particle diameter (μm) of Al
0.5
0.5
0.5
0.5
0.5
0.5
0.5
source material
Average particle diameter (μm) of raw
42
42
42
42
42
42
42
material 1
Average particle diameter (μm) of raw
4
4
4
4
4
4
4
material 2
Al content (ppm) in terms of its oxide in raw
3650
130
410
560
930
1190
8710
material 1
Al content (ppm) in terms of its oxide in raw
510
130
200
260
360
450
1960
material 2
Burners for spraying raw materials 1 and 2
Separate
Separate
Separate
Separate
Separate
Separate
Separate
Condition for
Flow rate (m 3 /hr) of LPG for forming flame
16
16
16
16
16
16
16
dissolution
Flow rate (m 3 /hr) of oxygen for forming flame
96
96
96
96
96
96
96
Amount (kg/hr) of raw material 1 supplied
15
15
15
15
15
15
15
into flame
Amount (kg/hr) of raw material 2 supplied
8
8
8
8
8
8
8
into flame
Amorphous
Content (ppm) of Al in a first portion of
3610
130
370
520
900
1080
8600
siliceous powder
amorphous siliceous powder, having a particle
size range of 15 μm or more and less than
70 μm, in terms of its oxide
Content (ppm) of Al in a second portion of
490
110
190
260
340
390
1850
amorphous siliceous powder, having particle
size range of 3 μm or more and less than
15 μm, in terms of its oxide
Content (ppm) of Al in amorphous siliceous
2730
130
250
340
480
590
6330
powder including the entire particle size range,
in terms of its oxide
Combined content (% by mass) of Si and Al
99.8
99.9
99.9
99.9
99.9
99.9
99.7
in terms of their oxides
Content ratio of Al (A)/(B)
7.4
1.2
1.9
2.0
2.6
2.8
4.6
Maximum value of first peak (μm)
44
48
44
44
44
48
44
Maximum value of second peak (μm)
5
5
5
6
5
6
6
Average particle diameter (μm)
31
33
31
33
32
33
32
Maximum particle diameter (μm)
194
213
213
194
177
177
134
Amorphous rate (%)
99.7
99.9
99.9
99.8
99.6
99.7
99.8
Average sphericity (—)
0.92
0.92
0.91
0.90
0.92
0.90
0.90
Combination ratio
Epoxy resin 1 (% by mass)
—
—
—
—
—
—
—
of semiconductor
Epoxy resin 2 (% by mass)
5.7
5.7
5.7
5.7
5.7
5.7
5.7
sealing material
Phenol resin 1 (% by mass)
6.0
6.0
6.0
6.0
6.0
6.0
6.0
Phenol resin 2 (% by mass)
—
—
—
—
—
—
—
Coupling agent 1 (% by mass)
—
—
—
—
—
—
—
Coupling agent 2 (% by mass)
0.4
0.4
0.4
0.4
0.4
0.4
0.4
Curing accelerator 1 (% by mass)
0.2
0.2
0.2
0.2
0.2
0.2
0.2
Curing accelerator 2 (% by mass)
—
—
—
—
—
—
—
Mold releasing agent (% by mass)
0.3
0.3
0.3
0.3
0.3
0.3
0.3
Amorphous siliceous powder (% by mass)
87.4
87.4
87.4
87.4
87.4
87.4
87.4
Curelastometer torque (N · m)
3.7
4.5
4.6
4.3
4.2
3.9
3.8
Wire transformation ratio (%)
0
2
2
1
1
0
0
Spiral flow (cm)
130
121
120
125
124
133
129
TABLE 2
Example
Example
Example
Example
Example
Item
Example 8
Example 9
10
11
12
13
14
Raw material
Type of Al source material
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
siliceous powder
Average particle diameter (μm) of Al
0.5
0.5
0.5
0.5
0.5
0.5
0.5
source material
Average particle diameter (μm) of raw
42
42
42
42
42
42
10
material 1
Average particle diameter (μm) of raw
4
4
4
4
4
4
2
material 2
Al content (ppm) in terms of its oxide in raw
14920
15960
19880
23220
29730
3650
3490
material 1
Al content (ppm) in terms of its oxide in raw
2870
3330
4880
5170
6790
510
1210
material 2
Burners for spraying raw materials 1 and 2
Separate
Separate
Separate
Separate
Separate
Separate
Separate
Condition for
Flow rate (m 3 /hr) of LPG for forming flame
16
16
16
16
16
12
14
dissolution
Flow rate (m 3 /hr) of oxygen for forming flame
96
96
96
96
96
72
84
Amount (kg/hr) of raw material 1 supplied
15
15
15
15
15
24
7
into flame
Amount (kg/hr) of raw material 2 supplied
8
8
8
8
8
13
16
into flame
Amorphous
Content (ppm) of Al in a first portion of
14890
15680
19100
22450
28700
3670
3510
siliceous powder
amorphous siliceous powder, having a particle
size range of 15 μm or more and less than
70 μm, in terms of its oxide
Content (ppm) of Al in a second portion of
2880
3460
4820
5220
6830
530
1320
amorphous siliceous powder, having particle
size range of 3 μm or more and less than
15 μm, in terms of its oxide
Content (ppm) of Al in amorphous siliceous
11780
12470
16480
18080
23450
2800
2070
powder including the entire particle size range,
in terms of its oxide
Combined content (% by mass) of Si and Al
99.8
99.8
99.8
99.8
99.7
99.9
99.9
in terms of their oxides
Content ratio or Al (A)/(B)
5.2
4.5
4.0
4.3
4.2
6.9
2.7
Maximum value of first peak (μm)
44
48
44
44
44
48
12
Maximum value of second peak (μm)
7
5
6
5
7
7
2
Average particle diameter (μm)
33
32
32
31
31
35
4
Maximum particle diameter (μm)
161
194
161
134
194
213
58
Amorphous rate (%)
99.7
99.7
99.6
99.5
99.5
99.5
99.9
Average sphericity (—)
0.90
0.91
0.92
0.90
0.92
0.83
0.92
Combination ratio
Epoxy resin 1 (% by mass)
—
—
—
—
—
—
—
of semiconductor
Epoxy resin 2 (% by mass)
5.7
5.7
5.7
5.7
5.7
5.7
5.7
sealing material
Phenol resin 1 (% by mass)
6.0
6.0
6.0
6.0
6.0
6.0
6.0
Phenol resin 2 (% by mass)
—
—
—
—
—
—
—
Coupling agent 1 (% by mass)
—
—
—
—
—
—
—
Coupling agent 2 (% by mass)
0.4
0.4
0.4
0.4
0.4
0.4
0.4
Curing accelerator 1 (% by mass)
0.2
0.2
0.2
0.2
0.2
0.2
0.2
Curing accelerator 2 (% by mass)
—
—
—
—
—
—
—
Mold releasing agent (% by mass)
0.3
0.3
0.3
0.3
0.3
0.3
0.3
Amorphous siliceous powder (% by mass)
87.4
87.4
87.4
87.4
87.4
87.4
87.4
Curelastometer torque (N · m)
3.6
4.3
4.2
4.4
4.5
4.0
4.2
Wire transformation ratio (%)
1
1
1
2
1
1
1
Spiral flow (cm)
128
125
123
117
118
125
116
TABLE 3
Example
Example
Example
Example
Example
Example
Example
Item
15
16
17
18
19
20
21
Raw material
Type of Al source material
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al(OH) 3
siliceous powder
Average particle diameter (μm) of Al
0.5
0.5
0.5
0.5
12
0.03
0.5
source material
Average particle diameter (μm) of raw
42
50
15
62
42
42
42
material 1
Average particle diameter (μm) of raw
4
16
3
12
4
4
4
material 2
Al content (ppm) in terms of its oxide in raw
8710
12070
9590
26770
4810
4950
8480
material 1
Al content (ppm) in terms of its oxide in raw
420
620
420
1260
350
1110
3130
material 2
Burners for spraying raw materials 1 and 2
Separate
Separate
Separate
Seperate
Separate
Seperate
Separate
Condition for
Flow rate (m 3 /hr) of LPG for forming flame
16
16
14
18
16
16
16
dissolution
Flow rate (m 3 /hr) of oxygen for forming flame
96
96
84
108
96
96
96
Amount (kg/hr) of raw material 1 supplied
15
15
15
14
15
15
15
into flame
Amount (kg/hr) of raw material 2 supplied
8
8
8
9
8
8
8
into flame
Amorphous
Content (ppm) of Al in a first portion of
8530
10440
9360
24520
4730
4750
8150
siliceous powder
amorphous siliceous powder, having a particle
size range of 15 μm or more and less than
70 μm, in terms of its oxide
Content (ppm) of Al in a second portion of
410
950
500
1570
360
1240
3190
amorphous siliceous powder, having particle
size range of 3 μm or more and less than
15 μm, in terms of its oxide
Content (ppm) of Al in amorphous siliceous
5790
6980
6510
15930
2320
3630
6710
powder including the entire particle size range,
in terms of its oxide
Combined content (% by mass) of Si and Al
99.7
99.7
99.8
99.9
99.8
99.8
99.8
in terms of their oxides
Content ratio of Al (A)/(B)
21
11
19
16
13
3.8
2.6
Maximum value of first peak (μm)
44
53
16
63
48
44
48
Maximum value of second peak (μm)
5
16
3
13
6
5
6
Average particle diameter (μm)
31
39
11
43
32
30
33
Maximum particle diameter (μm)
194
213
70
234
194
161
194
Amorphous rate (%)
99.8
99.8
99.8
99.7
99.8
99.8
99.7
Average sphericity (—)
0.91
0.89
0.89
0.88
0.88
0.90
0.90
Combination
Epoxy resin 1 (% by mass)
—
—
—
—
—
—
—
ratio of
Epoxy resin 2 (% by mass)
5.7
5.7
5.7
5.7
5.7
5.7
5.7
semiconductor
Phenol resin 1 (% by mass)
6.0
6.0
6.0
6.0
6.0
6.0
6.0
sealing material
Phenol resin 2 (% by mass)
—
—
—
—
—
—
—
Coupling agent 1 (% by mass)
—
—
—
—
—
—
—
Coupling agent 2 (% by mass)
0.4
0.4
0.4
0.4
0.4
0.4
0.4
Curing accelerator 1 (% by mass)
0.2
0.2
0.2
0.2
0.2
0.2
0.2
Curing accelerator 2 (% by mass)
—
—
—
—
—
—
—
Mold releasing agent (% by mass)
0.3
0.3
0.3
0.3
0.3
0.3
0.3
Amorphous siliceous powder (% by mass)
87.4
87.4
87.4
87.4
87.4
87.4
87.4
Curelastometer torque (N · m)
4.4
4.2
3.9
4.3
4.4
4.1
4.2
Wire transformation ratio (%)
1
2
1
2
1
1
0
Spiral flow (cm)
123
120
129
116
122
128
125
TABLE 4
Example
Example
Example
Example
Example
Example
Example
Item
22
23
24
25
26
27
28
Raw material
Type of Al source material
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
siliceous powder
Average particle diameter (μm) of Al
10
8
0.5
0.5
0.5
0.5
0.5
source material
Average particle diameter (μm) of raw
72
42
42
42
15
15
30
material 1
Average particle diameter (μm) of raw
7
4
4
4
3
3
5
material 2
Al content (ppm) in terms of its oxide in raw
1360
1090
3650
410
13940
5920
28110
material 1
Al content (ppm) in terms of its oxide in raw
200
1770
510
200
5300
4300
5030
material 2
Burners for spraying raw materials 1 and 2
Separate
Separate
Separate
Separate
Separate
Separate
Separate
Condition for
Flow rate (m 3 /hr) of LPG for forming flame
18
16
16
16
14
14
16
dissolution
Flow rate (m 3 /hr) of oxygen for forming flame
108
96
96
96
84
84
96
Amount (kg/hr) of raw material 1 supplied
16
15
15
15
12
10
16
into flame
Amount (kg/hr) of raw material 2 supplied
7
8
8
8
11
13
7
into flame
Amorphous
Content (ppm) of Al in a first portion of
1330
1180
3610
370
13380
5780
27330
siliceous powder
amorphous siliceous powder, having a particle
size range of 15 μm or more and less than
70 μm, in terms of its oxide
Content (ppm) of Al in a second portion of
210
1650
490
190
5510
4310
5380
amorphous siliceous powder, having particle
size range of 3 μm or more and less than
15 μm, in terms of its oxide
Content (ppm) of Al in amorphous siliceous
1020
1410
2730
250
9770
5610
21140
powder including the entire particle
size range, in terms of its oxide
Combined content (% by mass) of Si and Al
99.9
99.9
99.8
99.9
99.8
99.9
99.8
in terms of their oxides
Content ratio of Al (A)/(B)
6.3
0.7
7.4
1.9
2.4
1.3
5.1
Maximum value of first peak (μm)
76
44
44
44
15
15
31
Maximum value of second peak (μm)
9
7
5
5
3
3
6
Average particle diameter (μm)
54
32
31
31
9
7
24
Maximum particle diameter (μm)
234
213
194
213
70
70
111
Amorphous rate (%)
99.5
99.7
99.7
99.9
99.8
99.8
99.7
Average sphericity (—)
0.86
0.90
0.92
0.91
0.93
0.90
0.92
Combination ratio
Epoxy resin 1 (% by mass)
—
—
6.7
6.7
—
1.2
—
of semiconductor
Epoxy resin 2 (% by mass)
5.7
5.7
—
—
5.3
4.3
5.7
sealing material
Phenol resin 1 (% by mass)
6.0
6.0
—
6.0
—
—
6.0
Phenol resin 2 (% by mass)
—
—
5.3
—
5.1
5.1
—
Coupling agent 1 (% by mass)
—
—
0.4
0.4
—
—
0.4
Coupling agent 2 (% by mass)
0.4
0.4
—
—
0.4
0.4
—
Curing accelerator 1 (% by mass)
0.2
0.2
0.2
0.1
0.2
0.2
0.2
Curing accelerator 2 (% by mass)
—
—
—
0.2
—
—
—
Mold releasing agent (% by mass)
0.3
0.3
0.3
0.3
0.3
0.3
0.3
Amorphous siliceous powder (% by mass)
87.4
87.4
87.1
86.3
88.7
88.5
87.4
Curelastometer torque (N · m)
4.7
4.4
3.5
4.3
4.5
4.4
4.3
Wire transformation ratio (%)
2
2
0
2
1
1
1
Spiral flow (cm)
114
119
133
122
118
123
122
TABLE 5
Com-
Com-
Com-
Com-
Com-
Com-
Com-
parative
parative
parative
parative
parative
parative
parative
Item
Example 1
Example 2
Example 3
Example 4
Example 5
Example 6
Example 7
Raw material
Type of Al source material
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
siliceous powder
Average particle diameter (μm) of Al
0.5
0.5
0.5
0.5
0.5
0.5
8
source material
Average particle diameter (μm) of raw
42
42
42
42
42
72
10
material 1
Average particle diameter (μm) of raw
4
4
4
4
4
7
2
material 2
Al content (ppm) in terms of its oxide in raw
70
34140
14870
8510
90
70
430
material 1
Al content (ppm) in terms of its oxide in raw
70
7360
2700
7360
120
60
80
material 2
Burners for spraying raw materials 1 and 2
Separate
Separate
same
Separate
Separate
Separate
Separate
Condition for
Flow rate (m 3 /hr) of LPG for forming flame
16
16
16
16
16
18
14
dissolution
Flow rate (m 3 /hr) of oxygen for forming flame
96
96
96
96
96
108
84
Amount (kg/hr) of raw material 1 supplied
15
15
15
15
15
16
7
into flame
Amount (kg/hr) of raw material 2 supplied
8
8
8
8
8
7
16
into flame
Amorphous
Content (ppm) of Al in a first portion of
70
31810
12080
8410
80
60
410
siliceous powder
amorphous siliceous powder, having a particle
size range of 15 μm or more and less than
70 μm, in terms of its oxide
Content (ppm) of Al in a second portion of
60
7190
11210
7390
130
70
70
amorphous siliceous powder, having particle
size range of 3 μm or more and less than
15 μm, in terms of its oxide
Content (ppm) of Al in amorphous siliceous
70
25910
11980
8250
110
60
170
powder including the entire particle size
range, in terms of its oxide
Combined content (% by mass) of Si and Al
99.9
99.7
99.8
99.7
99.9
99.9
99.9
in terms of their oxides
Content ratio of Al (A)/(B)
1.2
4.4
1.1
1.1
0.6
0.9
5.9
Maximum value or first peak (μm)
44
48
48
44
44
76
12
Maximum value of second peak (μm)
5
6
8
6
4
8
2
Average particle diameter (μm)
31
33
33
32
30
52
4
Maximum particle diameter (μm)
194
177
213
194
177
234
58
Amorphous rate (%)
99.7
99.3
99.7
99.8
99.7
99.6
99.8
Average sphericity (—)
0.90
0.88
0.90
0.91
0.89
0.88
0.91
Combination ratio
Epoxy resin 1 (% by mass)
—
—
—
—
—
—
—
of semiconductor
Epoxy resin 2 (% by mass)
5.7
5.7
5.7
5.7
5.7
5.7
5.7
sealing material
Phenol resin 1 (% by mass)
6.0
6.0
6.0
6.0
6.0
6.0
6.0
Phenol resin 2 (% by mass)
—
—
—
—
—
—
—
Coupling agent 1 (% by mass)
—
—
—
—
—
—
—
Coupling agent 2 (% by mass)
0.4
0.4
0.4
0.4
0.4
0.4
0.4
Curing accelerator 1 (% by mass)
0.2
0.2
0.2
0.2
0.2
0.2
0.2
Curing accelerator 2 (% by mass)
—
—
—
—
—
—
—
Mold releasing agent (% by mass)
0.3
0.3
0.3
0.3
0.3
0.3
0.3
Amorphous siliceous powder (% by mass)
87.4
87.4
87.4
87.4
87.4
87.4
87.4
Curelastometer torque (N · m)
7.0
6.8
7.2
6.0
6.7
7.2
5.6
Wire transformation ratio (%)
5
7
8
4
5
7
5
Spiral flow (cm)
101
98
112
118
105
90
107
TABLE 6
Comparative
Comparative
Comparative
Comparative
Comparative
Item
Example 8
Example 9
Example 10
Example 11
Example 12
Raw material
Type of Al source material
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
Al 2 O 3
siliceous powder
Average particle diameter (μm) of Al source material
0.5
0.5
0.5
0.5
0.5
Average particle diameter (μm) of raw material 1
15
42
42
42
50
Average particle diameter (μm) of raw material 2
3
4
4
4
16
Al content (ppm) in terms of its oxide in raw material 1
33890
29730
34140
14870
35900
Al content (ppm) in terms of its oxide in raw material 2
1560
6790
7360
2700
1210
Burners for spraying raw materials 1 and 2
Separate
Separate
Separate
same
Separate
Condition for
Flow rate (m 3 /hr) of LPG for forming flame
14
16
16
16
16
dissolution
Flow rate (m 3 /hr) of oxygen for forming flame
84
96
96
96
96
Amount (kg/hr) of raw material 1 supplied into flame
14
15
15
15
15
Amount (kg/hr) of raw material 2 supplied into flame
9
8
8
8
8
Amorphous
Content (ppm) of Al in a first portion of amorphous
32110
27900
31810
12080
33140
siliceous powder
siliceous powder, having a particle size range of
15 μm or more and less than 70 μm, in
terms of its oxide
Content (ppm) of Al in a second portion of amorphous
1910
6910
7190
11210
1610
siliceous powder, having particle size range of 3 μm
or more and less than 15 μm, in terms of its oxide
Content (ppm) of Al in amorphous siliceous powder
21370
23050
25910
11980
22870
including the entire particle size range,
in terms of its oxide
Combined content (% by mass) of Si and Al in terms
99.7
98.1
99.7
99.8
99.7
of their oxides
Content ratio of Al (A)/(B)
17
4.0
4.4
1.1
21
Maximum value or first peak (μm)
15
44
48
48
51
Maximum value of second peak (μm)
3
5
6
8
16
Average particle diameter (μm)
10
31
33
33
38
Maximum particle diameter (μm)
70
213
177
213
213
Amorphous rate (%)
99.8
99.7
99.3
99.7
99.8
Average sphericity (—)
0.90
0.91
0.88
0.90
0.90
Combination ratio
Epoxy resin 1 (% by mass)
6.7
6.8
6.7
—
—
of semiconductor
Epoxy resin 2 (% by mass)
—
—
—
5.3
5.3
sealing material
Phenol resin 1 (% by mass)
—
6.0
—
—
—
Phenol resin 2 (% by mass)
5.3
—
5.3
5.1
5.1
Coupling agent 1 (% by mass)
—
—
0.4
—
0.4
Coupling agent 2 (% by mass)
0.4
0.4
—
0.4
—
Curing accelerator 1 (% by mass)
0.2
0.2
0.2
0.2
0.2
Curing accelerator 2 (% by mass)
—
—
—
—
—
Mold releasing agent (% by mass)
0.3
0.3
0.3
0.3
0.3
Amorphous siliceous powder (% by mass)
87.1
86.3
87.1
88.7
88.7
Curelastometer torque (N · m)
7.0
6.1
6.9
6.7
6.3
Wire transformation ratio (%)
6
4
5
7
7
Spiral flow (cm)
110
117
105
110
103
As is evident from the comparison of Examples with Comparative Examples, according to the amorphous siliceous powder of the present invention, it is possible to prepare the resin composition, in particular the semiconductor sealing material which is more excellent in fluidity, viscosity property and molding property than Comparative Examples.
INDUSTRIAL APPLICABILITY
The amorphous siliceous powder of the present invention is used in semiconductor sealing materials used for automobiles, portable electronic devices, personal computers, electrical home appliances and the like, and as a filler for laminated sheets on which semiconductors are mounted. The resin composition of the present invention can also be used for prepregs for print substrates impregnating and curing in a glass fabric, a glass nonwoven or another organic substrate, and as various engineered plastics, in addition to use in a semiconductor sealing material. | 4y
|
RELATED APPLICATIONS
This is a continuation-in-part application of U.S. patent application Ser. No. 326,578, filed Dec. 2, 1981, by the inventor herein and entitled "Combination Table Saw", now abandoned, which application is a continuation-in-part of U.S. patent application Ser. No. 138,288, filed by the inventor herein on Apr. 8, 1980, and entitled "The Combination Table Saw", now abandoned, specific mention of which is being made to obtain benefit of the filing dates thereof.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates in general to table saws.
2. Prior Art
There have been a multitude of table saw designs such as is seen in the following U.S. Patents.
______________________________________U.S.Pat. No. INVENTOR ISSUED TITLE______________________________________1,813,783 Tomlinson, et al 07/07/31 "Saw Table"2,247,314 Sellmeyer 06/24/41 "Portable Power Saw"2,729,250 Gilkey 01/03/56 "Portable Saw Table Containing Sliding Portion"2,870,802 Richards 01/27/59 "Under-Table Traveling-Saw Apparatus For Cutting Sheet of Materials"2,933,113 Meyer 04/19/60 "Combo-Trolley-Bench"3,456,697 Rutzebeck 07/22/69 "Traveling Arbor Saw"4,068,550 Gray, et al 01/17/78 "Foldable Bench For A Portable Hand-Held Circular Saw"______________________________________
However, the difficulty with these and other prior art saw table designs has been their lack of versatility; i.e., inability to handle large pieces of lumber, inability to perform cross-cutting, mitering and ripping operations. An additional difficulty with these prior art saw table designs is that, with each, the carriage and track cannot be extended past the edge of the table top.
SUMMARY OF THE INVENTION
Therefore, it is an object of this invention to provide a table saw which can easily cross-cut, miter or rip small lumber strips as well as large lumber sheets without the need for extraneous extension structures.
Another object of this invention is to provide a table saw that is safe to operate and can quickly be converted from one type of sawing operation to another.
Still another object of this invention is to provide a table saw that can accurately cross-cut, miter or rip a piece of lumber.
Other objects and advantages of this invention shall become apparent from the ensuing descriptions of the invention.
Accordingly, a table saw is provided comprising a circular power driven saw fixedly mounted on a carriage assembly attached to a track assembly in a manner to allow lengthwise movement of the carriage assembly on the track assembly, the track assembly being attached to a frame structure to allow movement of the track assembly on the frame which is parallel to the carriage movement, a miter-rip fence variably positionable on a table top attached to the top of the frame structure, the fence having attaching means allowing fixed attachment of the fence to the table top in a desired position, and the table top having a channel for the blade of the saw to extend through.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a table saw of this invention;
FIG. 2 is an exploded, perspective view of the table structure having track guide rollers, the track assembly and the carriage assembly.
FIG. 3 is a perspective view of the track and carriage assemblies mounted on the frame structure.
FIG. 4 is a front view of the carriage assembly mounted on the track assembly and frame structure.
FIG. 5 is a side view of the track with centering means preferred in this invention.
FIG. 6 is a top view of the track with centering means and carriage assembly mounted on track assembly preferred in this invention.
FIG. 7 is an exploded, perspective view of the saw, saw mounting assembly and saw control assembly.
FIG. 8 is a perspective view of the saw and saw mounting and saw control assemblies positioned on the carriage assembly.
FIG. 9 is a top view of the table top illustrating the miter-rip fence positioning openings and positioning of the miter-rip fence thereon.
FIG. 10 is an exploded, perspective view of the miter-rip fence positioning adjusting assembly and table locking assembly.
FIG. 11 is a side view of the leaf guard body utilized to protect the upper portion of the saw blade.
FIG. 12 is a side view of the material rest shoe extension mountable to the track and material rest shoe.
FIG. 13 is a side view of the miter-rip fence locking feet positioned in the table top positioning opening.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the figures, and particularly FIG. 1, a preferred embodiment of the combination saw is illustrated comprising, in general, a circular power driven saw 2 fixedly mounted on a carriage assembly 3, a track assembly 4 mounted for horizontal movement to a frame structure 5, and an extendable table top 6 attached to frame structure 5 and having a channel 7 through which saw 2 protrudes.
In this embodiment, frame structure 5 is constructed with an upper box shaped structure having parallel side walls 8 and parallel end walls 9 welded or bolted together to form a rigid frame on top of which table top 6 can be attached. End walls 9 are cut away to form a passageway 10 for track assembly 4 and saw 2 to pass during ripping operations described below. If the combination saw is not a table model, then legs 11 are bolted or welded to the frame walls 8 and 9 as shown to raise the table top to the desired work level. For additional support, cross-members 12 are fixedly attached to legs 11 as shown.
In FIGS. 2-6, carriage assembly 3 and track assembly 4 are illustrated. Carriage assembly 3 comprises a saw mounting frame having a material support guide 14 fixedly mounted by screws 15 to the front end of frame 13 as shown, which material support guide 14 is shaped and positioned to slidingly fit in table top channel 7 (FIG. 1). Frame 13 is further provided with four roller assemblies 16, which are attached at the four corners of frame 13. Each assembly 16 has a mounting plate 17 fixedly attached to the underside of frame 13 by screws 18 as shown. Each plate 17 has a roller axle 19 extending below and outward from plate 17 on which rollers 20 are rotatably mounted and held in position by screws 21. Frame 13 is also provided with tabs 22, which protrude downward and have threaded opening 23 through which threaded axle 24 rotatably positions upper track rollers 25. Each roller 20 and 24 is properly positioned to rest on the underside of track side bars 26 of track assembly 4 (see FIG. 4), so that carriage assembly 3 can be horizontally moved back and forth on track side bars 26.
Frame 13 is provided with a lower shoulder piece 27 having an opening 28 through which pin 29 can extend into track side bar opening 30 to lock frame 13 in fixed position relative to track side bar 26. Spring 31 is mounted on pin 29 and exerts a force against both lower shoulder piece 27 and pin plate 32 so that when pin tip 33 is aligned with track side bar opening 30, pin tip 33 will enter opening 30, thus locking carriage assembly 3 in place relative to track assembly 4.
To slidingly mount track assembly 4 on frame structure 5, frame end walls 9 are provided with L-shaped opposing pieces 34 and 35, to which are mounted, by screws 36, six track roller assemblies 37, three on each piece. Preferably, one track piece 34 is mounted on each end and one in the middle, as shown in FIG. 2. Pieces 34 and 35 have slotted holes so roller assemblies 37 can be moved to assist in aligning the carriage assembly 3 and track assembly 7 on frame 13 to allow the material rest shoe 14 to easily pass through channel 7. Each assembly 37 comprises a roller mounting bracket 38 having an upper axle 39 and a lower axle 40 to which is rotatably mounted upper roller 41 and lower roller 42, which are held in position thereon by screws 43. Rollers 41 and 42 are positioned to contact track side bar 26, as shown more clearly in FIG. 4. In this manner, rollers 20, 25, 41 and 42 form a fixed path in which track side bar 26 can horizontally move.
As shown in FIGS. 2 and 6, front bar 44 is constructed of tubular members 45 and 46, which telescope into one another. Members 45 and 46 are provided with multiple threaded openings 47 (FIG. 6), which can be aligned with one another to allow adjustment of the width of front bar 44. This insures that track side bars 26 will properly fit in the path formed by rollers 20, 25, 41 and 42. Once the proper width is obtained, screws 48 are positioned in openings 47 to fix the position of members 45 and 46 relative to one another.
As shown in FIGS. 2, 3, 5 and 6, track assembly 4 is provided with front and rear carriage assembly stops 49 and 50 to prevent track assembly 4 from being pushed or pulled out of the frame structure 5.
Track assembly 4 is provided with an automatic repositioning assembly 51, which comprises a spring-loaded spool 52 of line 53 mounted by brackets 54 which are fixed by screws 55 to L-shaped piece 35. Line 53 extends from spool 52 through opening 56 of piece 35 and attaches to bearing 57 which attaches to the bottom of rail 58 that is attached to track side bar 26, as shown in FIGS. 2 and 5. Spring 59 is attached at one end to axle 60 and at its other end to spool 52, so that as line 53 is unwound, spring 59 is twisted and will uncoil, turning spool 52 when track side bar 26 is released.
Finally, as seen in FIG. 2, frame end wall 9 is provided with table top mountings 61 to which table top 6 can be bolted as described hereinbelow.
Turning now to FIGS. 7 and 8, structure for mounting circular saw 2 to saw mounting frame 13 is shown. Saw 2 is attached to mounting bracket 62, which, in turn is pinned to hinge 63, by bracket pin 64, wherein hinge 63 is fixedly attached to brackets 13 by bolts 65.
Bracket 62 comprises arcuate section 66, which is perpendicular to table top 6 and having a parallel vertical height saw adjusting member 67, with arcuate slot 68 through which saw height positioning pin 69 passes. Blade tilt indicator bracket 70 is attached to frame 13 by bolts 71 and is provided with arcuate slot 72 through which angle indicator threaded pin 73 perpendicularly protruding from plate 74 of bracket 62 passes. Saw 2 is then held in the desired tilting position by tightening wing nut 75 on pin 73.
Saw motor 76 is provided with electrical cord 77, which plugs into a power source and a switch 79 attached to the rear of the carriage.
As shown in FIGS. 7, 8 and 11, blade guard assembly 81 is provided having a vertical mounted trigger assembly 82, comprising mounting plate 83 with trigger guard plates 84 to which trigger 85 is pivotally mounted by screw 86. Trigger 85 is attached to guard plates 84 by means of extension rod assembly 87 and in turn to connecting bracket 94 which is attached to mount 80, pivotally connecting members 88-93, pulley assembly 95 and springs 96 and 97 as shown in FIG. 7. When trigger 85 is squeezed, the blade guard is lifted to expose blade 78 to the piece of lumber being cut. Blade 78 is attached to saw 2 in conventional fashion by threaded bolt 98 and washer 99.
As shown seen in FIG. 11, an upper blade guard assembly 101 has sheaves 102-105 cantilevered about pin 106 attached to guard brace member 107 rigidly attached by bolts 108 and 109 to mounting plate 83. Each sheave is provided with a stop member 110 that strikes the protruding lip 111 of the sheave above it and causes the next sheave to rise. Starting with sheave 102, each one in succeeding order will be raised as the piece of lumber 112 strikes the lower portion of the sheave.
FIGS. 1 and 9 illustrate table top 6 which comprises base plates 113 and 114, which is attached to frame end wall foot plates 115-118 (see FIGS. 1, 3 and 9) by bolts 119. Side extension plates 120 and 121 can be attached to plates 113 and 114, respectively, as as well as back extension plate 122.
Both plates 113 and 114 are provided with locking guide holes 123 for positioning the miter-rip assembly 124.
Turning now to FIG. 10, miter-rip fence assembly 124 is shown, which comprises fence 125 with extension member 126 adjustably attached by tightening wing nuts 127 on threaded studs 128 projecting through slots 129, angle adjustment assembly 130 and locking foot assembly 131.
Angle adjustment assembly 130 is attached to base plate 132, which rests flat on table top 6 and is provided with locking foot opening 133, through which locking foot 152 can pass. Plate 132 is also provided with side piece 135 with threaded pin 136 for miter gauge wing nut 137 to screw into for holding miter gauge adjustment part 167 steady. Fitting on top of plate 132 is angle indicator plate 138 so that it pivots about pin 139, which passes through hollow stud 140 and opening 141 of table plate 132. Angle indicator plate 138 is provided with channel guide means 142 and 143, through which guide rods 144 and 145, respectively, extend. Rod 145 is provided with gear teeth 146 which are only on one side of rod 145 and which are operatively mating with gear 147 of conventional gear assembly 148.
Locking foot assembly 131, as seen in FIGS. 10 and 13, comprises locking foot 134, which pivots about pin 149 that extends through opening 150 of box 151, which is welded atop plate 132, as shown. Opening 150 is positioned so that foot member 152 protrudes below plate 132 and into locking guide holes 123 of either plate 113, 114, 120, or 121. Spring 153 is positioned on box stud 154 and protrudes to contact and exert pressure against curved handle 155 of locking foot 134. Locking arm 156 pivots about pin 157 and has cam head 158, which contacts handle 155, forcing it against spring 153 when locking arm 156 is rotated downward. Because both cam head 158 and locking foot head 159 are positioned off-center about pins 149 and 157, respectively, locking foot 134 is fixed in position when locking arm 156 has been rotated downward.
As shown in FIG. 13, locking; guide hole 123 is provided with indented area 160 to matingly accommodate the toe 161 of foot member 152 when locking arm 156 has been rotated downward. In this manner, miter-rip fence assembly 124 is held firmly in position on table top 6. By providing numerous holes 123, fence assembly 124 can be firmly positioned in almost any desired position.
Box cover 162, having locking arm opening 163, is attached to box 151 by bolts 164 to allow easy access to the locking foot and locking arm for repairs and maintenance.
As shown in FIG. 10, fence 125 is provided with a raised section 165 having an opening 166 that is positioned over table top channel 7 when fence 125 is being used for cross-cutting. This position is illustrated at "A" in FIG. 9. In this embodiment, opening 166 is high enough to allow saw blade 78 to pass underneath during the cutting operation. The same is true when fence 125 is in position "B".
FIG. 12 illustrates a material rest extension 168 having end 169 fitting over material rest tongue 170. Tongue 170 is provided with slot 171 (see FIG. 8) that fits about mating bottom tongue 172 to form a rigid structure having a flat surface formed by the top surfaces 173 and 174 of material rest extension 168 and material rest shoe 14, respectively. To further hold material rest extension 168 in rigid position, extension arm 175 extends downward and is provided with cupped section 176 that abutts against back bar 44 of track assembly 4. This material rest extension 168 is used when saw 2 is to be fixed in position and the lumber moved across the blade such as in a ripping operation.
Thus, as is clear from the above descriptions of the invention, fence assembly 124 can be used as a rip fence, as a stop fence or as a miter gauge, resulting in a multiple purpose saw that can operate on many different sizes of lumber.
There are, of course, alternate embodiments not specifically described but which are intended to be within the scope of this invention as defined by the following claims. | 4y
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BACKGROUND OF THE INVENTION
The present invention relates generally to a remotely controlled cutter apparatus for use within a conduit or pipe, and more particularly, to a remotely controlled cutter for use in re-establishing lateral connections in a previously lined sewer pipe or conduit.
It is generally well known that conduits or pipes which are employed for conducting fluids such as sanitary sewer pipes, storm sewer pipes, water lines, and gas lines, frequently require repair due to leakage. The leakage may be inwardly, from the environment into the pipe, or outwardly, from the pipe into the environment. The leakage may be due to improper formation or installation of the conduit or pipe, deterioration of the conduit or pipe due to ageing, attacks by acid or other corrosive materials, cracking due to earthquakes or vibrations caused by vehicular traffic, improper care, or a variety of other causes. Regardless of the cause, such leakage is undesirable because it may result in waste of the fluid being carried by the pipe, damage to the environment, and the possible creation of public health hazards.
Because of ever increasing labor and machinery cost, it is becoming increasingly more expensive to dig up and replace the leaking pipes or conduits. Additionally, it has become increasingly unacceptable and impractical to dig up the leaking pipes or conduits and physically replace them with new pipes due to the amount of space required by construction equipment and personnel, as well as the disruption to normal traffic patterns within a municipality.
As a result, various methods have been devised for the in situ repair or rehabilitation of existing pipes, thereby avoiding the expense, hazard, and inconvenience involved in digging up and replacing the leaking or damaged pipes. Some of these methods involve the insertion of an elongated flexible tubular liner comprised of felt or similar material that has been impregnated with a thermal setting synthetic resin into a deteriorated pipe. The liner is ultimately expanded and shaped to match the inner diameter of the pipe to be lined and the resin is allowed to cure to form a relatively hard, tight fitting, rigid pipe lining within the pipe. This liner effectively seals any cracks in the pipe and repairs any pipe or joint deterioration, thereby preventing further leakage either into or out of the pipe.
Another in situ repair technique involves the use of a folded polyethylene pipe in which a polyethylene pipe is generally folded into a U-shape cross-section and inserted into the damaged pipe. Thereafter, the U-shaped liner is expanded through use of temperature and pressure until it conforms with the shape of the inside surface of the original pipe wall.
Typically, the main conduit for a sanitary sewer system will have a plurality of connecting service entrances, or laterals, which carry sewage from individual sources into the main pipe. As is readily apparent, when the damaged pipe or conduit has been relined, all of the service entrances or laterals are effectively covered and sealed by the liner. Therefore, it is necessary to re-establish, or re-open, these lateral connections with the main sewer pipe. This can be accomplished by either digging up the earth adjacent the lateral connections and cutting holes in the liner corresponding to the lateral connection, or through use of a remotely controlled robotic cutter that is positioned within the lined main sewer pipe and may be operated so as to re-open or re-establish the openings from within the lined pipe.
Unlike prior art robotic cutters, the robotic cutter described herein enables a cutting tool to be rotated in a true circular arc about the longitudinal axis of the lateral pipe, thus ensuring that the opening for a lateral connection is a true circle. With prior art robotic cutters, the cutting tool cannot be rotated in a true circular path; rather, cutouts had to be made by manually controlling the longitudinal, vertical and/or rotational movement of the cutter head assembly. The prior art techniques require a very skilled cutter operator, are very time-consuming, and results in an inferior opening due to the erratic nature of the cut. Moreover, since the prior art robotic cutters cannot make a true circular cut, the openings made by such cutters is not uniform and frequently fail to fully open the lateral connection, thereby increasing the chances of subsequent blockage of the lateral openings.
SUMMARY OF THE INVENTION
The present invention provides an improved remotely controlled robotic cutter for re-establishing lateral connections in a re-lined pipe or conduit.
In a broad aspect, the invention disclosed herein comprises a system for generating a circular cut from within a main conduit to open a sealed lateral conduit connected to the main conduit. In a preferred embodiment, the robotic cutter has a cutting motor with a rotary cutting tool. In a preferred embodiment, the cutting tool rotates about its own axis as it is moved in a circular path or pattern which has the longitudinal axis of the lateral conduit as its approximate center. By adjusting the radius of rotation of the cutting tool, the cutting tool can be made to cut along the inner periphery of the cylindrical lateral conduit.
Due to the geometry of the junction of the intersecting lateral connection and the main conduit, the cutting tool will typically engage diametrically opposed points on the periphery of the junction between the lateral conduit and the main conduit. Accordingly, it is desirable that the rotating cutting tool be able to advance in a step-wise manner toward and along the axis of the lateral conduit during cutting operations. Step-wise advancement is also necessary as the cutting tool advances through a portion of the liner material with each circular rotation.
A turntable, or other suitable support member, is provided to support the cutting motor as it is rotated around a line generally parallel to the axis of the lateral conduit. Moreover, in a preferred embodiment, the cutting motor and tool can also be moved within the main conduit in a direction generally parallel to the longitudinal axis of the main conduit, and may be rotated about such a longitudinal axis.
In a broad aspect, a preferred embodiment of the invention comprises a cutting assembly which is movable along and within the main conduit. More particularly, the apparatus comprises a body member having a longitudinal axis, a rotatable main shaft, one end of which is supported by and extends from the body member, and a turntable supported at the other end of the shaft so as to be rotatable with the shaft. Motors or other suitable power devices are housed within the body member and connected to the shaft so as to (1) extend and retract the shaft and the turntable relative to the body member, and (2) rotate the main shaft, and thus the turntable, generally about the axis of the main shaft or about an axis generally parallel to the longitudinal axis of the main conduit. The main shaft and the turntable are preferably coupled together by a transverse travel block which enables the turntable, and thus the cutting motor and tool, to move transversely relative to the axis of the main shaft and the main conduit, This transverse movement enables the cutting tool to be advanced toward the lateral conduit.
As set forth previously, the cutting tool affixed to the cutting motor is offset from the axis of rotation of the motor's rotatable support member so that the cutting tool travels in a circular track of rotation. To that end, the position of the cutting motor and tool is transversely adjustable relative to the axis of the rotatable support member.
Since it is preferred that the apparatus of the invention be remotely operable, it is preferred that motors or other suitable drive members be provided to effect the several desired motions. Thus, separate drive motors may be placed in the body member to drive the main shaft rotationally and longitudinally. Similarly, a drive motor may be provided in the main shaft to effect the transverse movement of the transverse travel block. Likewise, a drive motor may also be provided in the turntable to effect the rotational movement of the cutting motor, and thus the cutting tool. The cutting motor may be used to drive the cutting tool.
The several drive members may be remotely powered and controlled by suitable cabling extending through the main conduit and attachable to a control panel positioned above ground. Similarly, the apparatus may be secured in position within the main conduit by an expandable bag element, wall clamp, shoes or the like.
These and other aspects of the present invention will be readily apparent to those skilled in the art from a review of the figures and the description of the preferred embodiment of the improved robotic cutter disclosed and claimed herein.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing summary, as well as the following detailed description, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, a preferred embodiment of the present invention is shown in the drawings, it being understood that this invention is not to be considered limited to the precise arrangements and details shown therein. In the drawings:
FIG. 1A is a perspective side view of a preferred embodiment of the cutter apparatus of the present invention that is shown disposed within a subterranean sewer pipe, as well as a control panel for controlling the cutter apparatus;
FIG. 1B is a schematic drawing of the valving arrangement used to control and regulate the air supply to the cutter apparatus;
FIG. 2 is a perspective view of the front of the cutter apparatus;
FIG. 3 is a perspective side view of a portion of the cutter head assembly;
FIG. 4 is a perspective view of the cutter head assembly;
FIG. 5A is an exploded perspective view of the cutter head assembly;
FIG. 5B is a perspective view of an alternative belt drive configuration for rotation of the cutting motor;
FIG. 6 is a front elevation view of the vertical travel block used on the robotic cutter apparatus;
FIG. 7A is a front perspective view of the vertical travel block used on the robotic cutter apparatus;
FIG. 7B is an exploded perspective view of the rack employed in the vertical travel block;
FIG. 8A is a front elevation view of an alternative embodiment of the vertical travel block employing a belt drive;
FIG. 8B is a perspective drawing of the alternative belt drive system for the vertical travel block;
FIG. 8C is an exploded perspective view of the alternative beet drive system for the vertical travel block;
FIG. 9A is a front perspective view showing the robotic cutter with the cutter head assembly in an upside-down position;
FIG. 9B is a perspective view of the carriage and rail system used to support the robotic cutter within a sewer pipe;
FIG. 10 is a side elevation view of the internal components of the robotic cutter;
FIG. 11 is an elevation view of the rear cover plate of the robotic cutter;
FIG. 12 is a perspective view of a motor cradle employing an alternative belt drive system in the robotic cutter; and
FIG. 13 is a side elevation view of the internal components of the robotic cutter.
FIG. 13A is a cross section view of the forward seal of the robotic cutter.
FIG. 13B is a perspective view of a rear support member used in the robotic cutter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1A shows the overall configuration of a preferred embodiment of the robotic cutter 20 disposed in sewer pipe 26 that has previously been lined with liner 27. Also shown is lateral connection 28 which is connected to sewer pipe 26 via opening 30. The cutter 20 is generally comprised of cutter body 32, cutter head assembly 38, cutter carriage 34, anchor bladder 40, and valve assembly 42. The cutter carriage assembly 34 is comprised of bottom rails 36, upper rails 36A, and extensions 35. Similarly, there is a carriage 44 for the valve assembly 42 comprised of rails 46 and extensions 45. The control panel 22 allows an operator to remotely control the various functions capable of being performed by the robotic cutter 20. Although it is not shown in the drawings, the robotic cutter disclosed and claimed herein is used in conjunction with a television camera that is positioned so as to allow remote viewing of cutting operations. Such television cameras are routinely available and the present invention may be used with any of such cameras.
FIG. 1B schematically shows the valving arrangement used to control and regulate the air supply from the main air supply line 29 to the robotic cutter 20. The valving arrangement is contained in valve assembly housing 42. In particular, the valving arrangement is comprised of plurality of control valves 21A, 21B, and 21C, oiler 23, and regulator 25. Air to anchor bladder 40 is provided from air supply line 29 through regulator 25, control valve 21A then to bladder 40. Air is supplied to pneumatic motor 62 from air supply line 29, through oiler 23, control valve 21B, and through pneumatic motor air supply line 81. Similarly, air is supplied to cutting motor 56 from air supply line 29, through oiler 23, control valve 21C, and through cutting motor air supply line 80. Note that conduit 31 for electrical supply and control wires extends through main air supply line 29 and valve assembly housing 42 into the cutter body 32. A chain 33 is fixed to both the cutter body 32 and valve assembly housing 42 to prevent any stress on the pneumatic and electrical lines extending between cutter body 32 and valve assembly housing 42.
Referring now to FIGS. 2, 3, 4 and 5A, the cutter head assembly 38 is more specifically shown. Generally speaking, the cutter head assembly 38 is comprised of vertical travel block 48, turntable 50, motor 56 and hub 60. The turntable 50 is disposed for vertical travel within vertical travel block 48. Motor 56 is secured to motor height and angle adjustment bracket 52 by use of clamp 54 and motor mounting block 55 (shown in FIG. 5A). The motor height and angle adjustment brackets 52 are secured to base mounting block 157 through use of a plurality of screws 153. The base mounting block 157 is secured to worm wheel gear 78 with a plurality of base mounting block screws. Note that the motor height and adjustment brackets 52 have a plurality of holes 161 such that the brackets 52 may be shifted a certain distance laterally relative to the axis X--X as shown in FIG. 5A when the brackets 52 are secured to base mounting block 157. Motor 56 has cutting tool 58 attached thereto for use in cutting the liner of a lined sewer pipe to re-establish the lateral connections. Of course, cutting tool 58 may be of any desired shape or configuration that an operator deems practicable for the particular cutting operation at hand.
As shown in FIG. 5A, the present invention allows the motor 56 to be rotated 360° about a vertical axis shown as X--X in FIG. 5A. This rotation is accomplished by worm gear drive assembly 69 which is comprised of pneumatic motor 62, gears 74, worm gear 76 and worm wheel gear 78. Pneumatic motor air supply line 81 is used to supply air to pneumatic motor 62. In a particularly preferred embodiment, the pneumatic motor 62 is a 1/100 hp motor manufactured by Micro-Motors, Inc., Model No. MMR 0014; the worm gear 76 and worm wheel gear 78 is a worm and wheel gearbox, Model No. P30; manufactured by Hinchcliffe Precision Components. The specific gear ratio for the worm gear drive is approximately 10:1. An alternative design for the worm gear drive assembly 69 employing a belt drive is shown in FIG. 5B. In particular, FIG. 5B discloses the use of belt gears 90 and belt 92 for driving worm gear shaft 76 and worm wheel gear 78. Either embodiment of the worm gear drive assembly may be used on the invention disclosed herein.
The pneumatic motor 62 as well as gears 74 are protected by protective housings 64 and 66. The cutter head assembly 38 is secured to the main shaft 130 of the robotic cutter by hub 60. Hub 60, which is manufactured in one piece with vertical travel block 48 in a preferred embodiment, has a recess adapted to receive shaft 130 and the hub 60 is split such that screws 68 when tightened securely clamp hub 60 to shaft 130.
Air is supplied to cutting motor 56 through cutting motor air supply line 80. Cutting motor air supply line 80 is connected to turntable 50 through use of rotary swivel 82. In turn, air flows through hollow shaft 84, and air feed line 86 into motor 56.
The motor height and angle adjustment bracket 52, motor mounting block 55, and clamp 54 allow variable positioning of the motor 56, and thus cutting tool 58, at an angle relative to the axis X--X shown in FIG. 5A. The positioning of the motor 56, and cutting tool 58, is accomplished by varying the position of motor mounting block 55 in bracket 52. The motor mounting block 55 is secured at different heights and angles through use of a plurality of screws 57 and positioning holes 59 in bracket 52. This angled positioning of the motor enables the cutting tool 58 to be rotated in a true circular path at various radii about the axis X--X, thereby insuring a true circular cut of the pipe liner at a lateral connection.
The vertical drive assembly 94 is more fully shown in FIGS. 3 and 6. Generally speaking, the vertical drive assembly 94 is comprised of vertical drive motor 63, rack 96, pinion gear 98, driven gears 100, linear bearings 102, bearing shafts 104, turntable 50, and vertical travel block 48. The pinion gear 98 is attached to vertical travel motor 63 and is engaged with both driven gears 100. The driven gears 100 are attached to vertical travel block 48. The rack 96 is secured to the turntable 50 through use of a plurality of screws 106. The turntable 50 is free to travel vertically through use of linear bearings 102 which slide on bearing shafts 104. In FIG. 7A, the turntable 50 is shown in its lower-most position. Note that only one of the driven gears 100 is in contact with rack 96 when the turntable 50 is at either extended position. An alternative embodiment for the vertical drive assembly 94 is shown in FIGS. 8A, 8B and 8C. This alternative embodiment employs a belt drive as opposed to the pure gear drive described above. The alternative belt drive embodiment is comprised of drive gear 108, tension rollers 109, idler rollers 110, belt 112, and in the particular configuration shown in the drawings, requires a two-piece belt clamp 114 which is attached to turntable 50 through use of screws 116.
FIG. 9A shows the robotic cutter 20 with the cutter head assembly 38 in an inverted or downward position. FIG. 9B shows how carriage assembly 34 is secured to cutter body 32 through use of clamp 120 passing through slotted bracket 118 attached to upper rail 36A.
The internal components of the robotic cutter 20 are best shown in FIGS. 10, 11, 12 and 13, 13A and 13B. Referring to FIG. 10, front plate 123 and rear plate 122 are secured to cutter body 32 through use of a plurality of tie rods 124. O-rings 125 are disposed between the front and rear plates and the cutter body. Main shaft 130 extends into cutter body 32 through forward seal 139 and passes through linear bearing 170 and bearing assembly 140. Main shaft gear 141 is attached on one end of the main shaft 130. Bearing assembly 140 is disposed within motor cradle 138. Rotational motor 136 is also disposed within motor cradle 138 and has rotational motor gear 142 attached thereto for engagement with main shaft gear 141 attached to main shaft 130. A guide rod 132 also extends through the length of the cutter body assembly and through slide bearing opening 171 in motor cradle 138. Also shown in FIG. 10 is the air supply line 80 which is used to supply air to cutting motor 56. Forward seal 139, which is shown in more detail in FIG. 13A, is comprised of housing 139A, seals 139B, 139C, and O-ring 139D. Forward seal housing 139A is secured to cutter body 132 by bolting. In a preferred embodiment, the seals are Model. No. 8600 and 8400 manufactured by Parker and made from Nitroxile, a low friction material.
In a preferred embodiment, rotational motor 136 is a 1/150 hp motor manufactured by Globe Motors, Type No. CLL; bearing assembly 140 and 170 are teflon coated bearings manufactured by Pacific Bearings, and sold under the trademark Simplicity; main shaft gear 141 is a 50 tooth stainless steel spur gear manufactured by Berg; rotational motor gear 142 is a 20 tooth stainless steel spur gear, manufactured by Berg. The gear ratio between main shaft gear 141 and rotational motor gear 142 is 2.5:1.
The longitudinal feed assembly is shown more fully in FIG. 13, wherein longitudinal feed motor 134, longitudinal feed motor gear 152, longitudinal feed screw 146, and longitudinal feed screw gear 154 are shown. Longitudinal feed screw 146 extends through threaded bushing 135 which is mounted in opening 137 in motor cradle 138. Also shown is stop plate 143 and bearings 145 (shown on one end only) that allow the longitudinal feed screw 146 to turn freely when the longitudinal feed motor 134 is actuated.
In a preferred embodiment, longitudinal feed motor 134 is a 1/100 hp motor manufactured by Globe Motors, Type No. 1M-15; longitudinal feed screw 146 is a 1/2" diameter stainless steel two-start acme thread lead screw, manufactured by Nook Industries; threaded bushing 135 is a bronze or plastic bushing also manufactured by Nook Industries with mating threads; longitudinal feed motor gear 152 is a 30 tooth stainless steel spur gear manufactured by Berg; longitudinal feed screw gear 154 is a 24 tooth stainless steel spur gear also manufactured by Berg. The gear ratio between longitudinal feed motor gear 152 and longitudinal feed screw gear 154 is 1.25:1.
FIG. 11 is an elevational view of back plate 122 which shows tie rods 124, electrical connection 126, rear support shaft 128, longitudinal feed screw retainer cap 127, and guide rod retainer cap 129. Retainer caps 127 and 129 allow insertion of longitudinal feed screw 146 and guide rod 132, respectively. Retainer cap 127 also holds the sleeve bearing associated with longitudinal feed screw 146. Threaded hole 131 is used to secure a bolt attached to chain 33 for restraint.
As shown in FIGS. 12, 13, and 13B, rear support shaft 128 supports the rear portion of main shaft 130 when main shaft 130, and motor cradle 138, are moved in a forward direction. Rear support shaft 128 is in sliding engagement with linear bearing 148A. In a preferred embodiment, linear bearing 148A is a teflon coated bearing assembly manufactured by Pacific Bearings and sold under the trademark Simplicity. Hole 128B and bore 128A in rear support shaft 128 are used to provide access for electrical utilities to the motor 63 disposed in main shaft 130. In a preferred embodiment, rear support shaft 128 is made of highly polished hardened stainless steel and sized such that it adequately supports the rearmost end of main shaft 130 when main shaft 130 is in its forward most position. In a particularly preferred embodiment, rear support shaft 128 is approximately 8" in length.
Lastly, FIG. 12 shows an alternative embodiment for the rotational drive assembly of the present invention in which a belt drive is used as opposed to direct gear to gear drive as described above. More particularly, this alternative belt drive employs a drive gear 147, driven gear 148 and belt 150.
Operation of the Robotic Cutter
The operation of the robotic cutter 20 will now be described. Initially, robotic cutter 20, valving assembly 42, and a television camera (not shown) will be inserted into a previously lined sewer pipe. Upon positioning of the robotic cutter 20 in the approximate location of the entrance of the lateral, bladder 40 will be inflated to secure the robotic cutter 20 within the sewer pipe 26. Of course, as is readily apparent, the height of the cutter carriage 34 and valve assembly carriage 44 may be adjusted through use of varying lengths of extensions 35 and 45, thereby allowing the robotic cutter disclosed herein to be used in pipes of varying diameter.
The longitudinal movement of the cutter head assembly 38 is accomplished by longitudinal feed motor 134, longitudinal feed motor gear 152, longitudinal feed screw gear 154, longitudinal feed screw 146, threaded bushing 135, and motor cradle 138. As best understood by reference to FIG. 13, actuation of longitudinal feed motor 134 causes longitudinal feed motor gear 152 to rotate which is engaged with longitudinal feed screw gear 154, thus causing longitudinal feed screw 146 to rotate within threaded bushing 135. As the longitudinal feed screw 146 is rotated, threaded bushing 135 travels along longitudinal feed screw 146, thereby causing motor cradle 138 (fixed to main shaft 130) and main shaft 130 to be advanced in a longitudinal direction. In turn, this causes cutter head assembly 38, which is fixed to main shaft 130, to be advanced in a longitudinal direction.
The rotational movement of the cutter head assembly 38 about the longitudinal axis of the main shaft 130 can be best understood by reference to FIG. 10. Rotation of the cutter head assembly 38 is accomplished by rotational motor 136, rotational motor gear 142, main shaft gear 141, bearing assembly 140, and main shaft 130. In operation, when rotational motor 136 is actuated, rotational motor gear 142 will rotate in engagement with main shaft gear 141, which is in turn secured to main shaft 130, thereby imparting rotational movement to main shaft 130. Main shaft 130 is free to rotate within bearing assembly 140 that is secured within motor cradle 138.
The mechanism for providing vertical travel of the cutter head assembly 38 is best shown with reference to FIGS. 3-7A. In particular, vertical travel motor 63, is disposed within shaft 130 adjacent hub 60. In turn, vertical travel motor 63 is connected to pinion gear 98 which in turn is connected to driven gears 100, at least one of which is in contact with rack 96. Note that pinion gear 98 is not in contact with rack 96 and that driven gears 100 are mounted onto vertical travel block 48. Thus, when vertical travel motor 63 is actuated, pinion gear 98 rotates thereby imparting rotation to driven gears 100 which causes the rack 96 to move vertically within vertical travel block 48. Of course, this causes turntable 50, which is secured to rack 96, to travel vertically. The turntable 50 is free to travel vertically through use of linear bearings 102 which slide on bearing shafts 104.
The rotational movement of cutter motor 56 is best understood by reference to FIGS. 2-5A. In particular, pneumatic motor 62 causes gears 74 to rotate thereby causing rotation of worm gear shaft 76 and ultimately worm wheel gear 78. Worm wheel gear 78 is secured to base mounting block 157 with a plurality of screws 159 extending into bushing 78A in worm wheel gear 78, thereby insuring that upon rotation of worm wheel gear 78, base mounting block 157 and thus motor 56, will rotate about the axis X--X shown in FIG. 5A.
As shown in FIG. 1A, the control panel 22 has several control knobs and switches for controlling the various functions of the cutter 20 during operation. In particular, on/off switch 161 is used to control electrical power to the control panel 122 and cutter 20; indicator light 163 is illuminated when on/off switch 161 is in the "on" position; joystick 160 is used to control the longitudinal and rotational movement of cutter head assembly 38; vertical control switch 162 is used to fully raise or lower the turntable 50; stepped vertical control switch 164 allows control of the amount of vertical stepping of the cutting tool 58 during cutting operations, which may be adjusted from approximately 5-50 thousandths of an inch per step; speed control knob 166 allows for the regulation of the time period during which electrical motor 63 is energized during operations; current limit override switches 168, 169, and 170 are used whenever it is deemed necessary by the operator to temporarily increase power to motors 63, 134, and 136, respectively, for any reasons, e.g., to push the cutter head assembly through debris; pneumatic control on/off switches 171, 172, and 173 are used to control the flow of air to bladder 40, pneumatic motor 62, and cutter motor 56, respectively; and reverse switches 174A, 174B, and 174C may be used to reverse the polarity of the current flowing through each of electric motors 63, 134, and 136, independently so that, for example, when cutter head assembly 38 is operated in a downward or inverted position, the operator's sense of direction will remain unchanged as the cutting tool 58 is moved to various positions during cutting operations. In a preferred embodiment, the current limit switches are switches manufactured by National Semiconductors, Inc. with an external pass transistor to increase capacity to enable continuous stalled motor operation.
With the robotic cutter described herein, the liner may actually be cut with cutting tool 58 as opposed to the grinding action that resulted from use of many prior art cutters. Many prior art cutters employ relatively large dome or cone-shaped "cutting" tools that, in actuality, grind the liner away. This grinding action of the prior art cutters generates a great amount of dust, thereby reducing visibility of cutting operations in an underground sewer pipe and adversely impacting the ability of an operator to achieve an efficient and effective cut. However, the present cutter, with its high-speed motor, is able to rotate the cutting tool 58 at speeds of approximately 20,000 rpm. Thus, the cutting tool of the invention described herein actually cuts the liner material, as opposed to grinding the lining material, and produces flakes, as opposed to dust, during cutting operations. The flakes resulting from use of the present invention have a less detrimental effect on the visibility of cutting operations than does the dust produced by prior art cutters.
Additionally, the present robotic cutter increases the speed with which laterals may be re-opened. In particular, a robotic cutter with cutting motor 56 and cutting tool 58 disclosed herein, allows liner material to be cut at a faster rate than a robotic: cutter using the large cone-shaped cutting tools commonly used on prior art cutters.
Another advantage of the present robotic cutter 20 is its relatively small size and weight which allows faster, safer, and easier handling of the device. In the preferred embodiment disclosed herein, the robotic cutter 20 (without valve assembly 42) is approximately 22" long and weighs approximately 25 pounds. The cylindrical housing for the cutter is approximately 4 1/2" in diameter and 1/8" inches thick. The cutter disclosed herein may be used in pipe sizes as small as 6".
Another feature of the present invention is that the cutter motor 56, and thus cutting tool 58, may be positioned at different heights and at different radial distances from the axis X--X as shown in FIG. 5A. The position of the cutting tool 58 at a higher inclined position allows the cutting tool 58 to extend further into the lateral thereby allowing removal of resin debris that may extend up into the lateral during the lining process. The adjustment of the radial distance from the axis X--X allows the cutter to be set to cut lateral openings of different sizes. The adjustments to the height and radial position of the cutting tool may be accomplished by shifting brackets 52 laterally relative to the X--X axis, by securing motor mounting block 55 at different heights within brackets 52, and by varying the length of tool 58, etc.
The vertical drive assembly 94 is also a unique feature of this invention in that it maximizes the vertical stroke of the robotic cutter while minimizing the overall physical dimension of the vertical drive assembly. With the gear drive mechanism shown in FIG. 6, the stroke length is approximately 1 1/2" from the centerline of main shaft 130 (3" total stroke). For the belt drive version shown in FIG. 8A, or for the gear drive version with an extended block and rack (not shown in the drawings) the total stroke length is approximately 5 inches. Thus, with the standard gear drive shown in FIG. 6, the robotic cutter may be used in 6-12" diameter pipe. With the belt drive version of the vertical drive assembly 94, as shown in FIG. 8A, the robotic cutter may be used on 12" and larger diameters pipes.
Another feature of the present invention is that each of the electrical motors previously described herein are current or torque limited by electronic circuits and can be stalled for an indefinite period of time during cutting operations. Through use of these circuits, the need for limit switches, and the accompanying circuitry, is eliminated.
For example, if an operator inadvertently or unwittingly tries to force the cutter head assembly 38 in a longitudinal direction when it is against a solid structure, the motor will stall at a certain current level and can maintain that level for as long as the operator tries to force the cutter head assembly 38 against the solid structure. Through use of these torque limiting electronic circuits, the cutter is made more durable and serviceable in that there is little likelihood that the motors will burn up during operations. However, the types of motors and circuits disclosed in the preferred embodiment should not be considered a limitation of the invention disclosed herein. Rather, the improved robotic cutter disclosed herein may employ any hydraulic, pneumatic, or electrical motor and still be within the scope of the invention. | 4y
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pallet shuttle for loading and unloading pallets from the table or bed of a machine tool, and more particularly to such a shuttle which is adapted for cooperation with a plurality of pallet storage positions located in a circular arrangement.
2. The Prior Art
Efforts to achieve maximum efficiency in the use of machine tools such as machine centers and the like, have resulted in the development of a variety of pallet shuttle mechanisms, in which pallet storage positions are located in a variety of positions. In all of these arrangements, some mechanism is provided for shifting a pallet from a storage position to a working position on the table of the machine tool, and for later returning the pallet to an assigned storage position. Most of the attempts in the prior art to develop such systems involve units of relatively great complexity, and the necessity for sequencing various actions of the apparatus so that the various steps necessary to be performed during the loading or unloading operation occur in the proper sequence.
It is desirable to provide a power handling mechanism which is relatively simple, and economically manufactured, and which readily performs a number of functions in sequence, so that they may not be accidentally performed in the wrong sequence.
BRIEF DESCRIPTION OF THE INVENTION
It is a principal object of the present invention to provide a simple and economical pallet shuttle mechanism, especially designed for a carousel, for cooperating with a number of pallet storage positions located in a circular arrangement. This shuttle mechanism incorporates a drive screw, and a drive screw nut which is movable rectilinearly in response to rotation of the screw. Means is provided for automatically locking or unlocking the drive screw nut to a pallet, whereby the pallet may be moved rectilinearly from the storage position to a rotating position, and, after subsequent rotation of the index table unit, moved to a machine tool operating position by further rectilinear motion of the drive screw. Locking and unlocking is accomplished automatically in response to the drive screw nut approaching or being retracted from an end position. A plurality of limit switches are operated by a single limit switch actuator for limiting movement of the drive screw nut in either direction, and for sensing when the drive screw nut first approaches and then reaches either of its extreme end positions. The result is a simple and economical means for handling pallets reliably by rectilinear motion to and from the rotatable index table, with automatic locking and unlocking means, and with a simple and effective means for determining when the maximum feed speed of the drive screw should be limited and stopped.
Other objects and advantages of the present invention will become manifest by an examination of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will now be made to the accompanying drawings in which:
FIG. 1 is a plan view of a carousel shuttle assembly incorporating an illustrative embodiment of the present invention;
FIG. 2 is a side elevational view of the apparatus of FIG. 1;
FIG. 3 is a side elevational view, partly in cross-section, of the pallet shuttle;
FIG. 4 is an end view, partly in cross-section, of the apparatus of FIG. 3;
FIG. 5 is a plan view of the apparatus of FIGS. 3 and 4;
FIG. 6 is a vertical cross-section of a pallet assembly used in connection with the apparatus of FIGS. 2-5;
FIG. 7 is a plan view of a pallet;
FIG. 8 is a side elevational view of a wing assembly comprising a pallet storage location; and
FIG. 9 is an end elevational view of the wing assembly of FIG. 8.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, a plan view of a carousel pallet shuttle is illustrated, in which a rotating index table 10 is provided, surrounded by a plurality of pallet storage locations 12-17. A pallet 18 is located at each of the pallet storage locations, except for the storage location 17, which is empty. The index table 10 supports a rotating pallet shuttle 20, and a further pallet 22 is illustrated in FIG. 1 as mounted on the rotating pallet shuttle 20.
Each of the pallet storage units 12-17 incorporates a unit bolted to a circular base plate 24 which surrounds the index table 10. In the case of the pallet storage location 17, a bracket 26 is bolted to the base 24, and a pair of ways 28 are secured to the bracket 26 for temporarily supporting a pallet such as the pallet 22. The pallet is adapted to be transferred from one of the storage locations 12-17 to the rotating pallet shuttle 20, which can rotate into alignment with the various pallet storage locations 12-17, and afterwards can rotate to the position illustrated in FIG. 1, so the pallet 22 can be moved radially outwardly from the rotating pallet shuttle into operating association with the machine tool 30. Machine operations are then performed on the work supported on the pallet 22, after which the pallet shuttle 20 retracts the pallet 22 from the machine tool 30, rotates to one of the pallet storage locations such as the location 17, and returns the pallet rectilinearly to a storage location.
FIG. 2 illustrates the carousel base 24, and one of the pallet storage units 32 bolted to the plate 24 by means of bolts 34. The storage unit 32 supports a pallet 18.
The index table 10 is also mounted on the base 24 for rotation about a vertical axis indicated by dashed line 36. Supported on the index table 10 is the rotating pallet shuttle 20, which is shown in FIG. 2 with a pallet in retracted position, namely nearest the axis 36. When in this position, the shuttle 20 with its pallet 22 may rotate past other storage positions, as indicated by the dashed lines 37 in FIG. 2 which show that the pallet shuttle with its pallet may be rotated past the pallet storge location supporting the pallet 18.
Parts of the rotating pallet shuttle 20 are shown in more detail in FIGS. 3 and 4.
In FIG. 4, a pair of tubular brackets 40 and 42 are mounted on top of a base plate 44 which is adapted to be bolted to the top surface of the base member 33 by bolts 46. A pair of support members 48 are secured to each of the hollow base members 40 and 42, and a pair of ways 50 are bolted to the members 48 by bolts (not shown). A drive screw nut 52 is provided with opposing slots for receiving the ways 50, and they slide horizontally along the ways 50, in a rectilinear direction. The ways 50 cooperate with the slots to prevent the drive screw nut 52 from moving vertically or horizontally relative to the ways.
The drive screw nut is threaded to receive a drive screw 54, so that by rotation of the drive screw, the nut 52 is moved forward and backwardly along the ways 50.
A side view of the drive screw 54 is illustrated in FIG. 3.
As shown in FIG. 3, the drive screw 54 is supported at one end by an end plate 56 in a bearing 58. The shaft of the screw 54 which is received in the bearing 58 has a slightly reduced diameter, and a retainer nut 60 is threaded onto the free end of the shaft on the other side of the bearing 58, so that the screw 54 is retained in longitudinal position relative to the end wall 56. A hydraulic motor 62 has a drive shaft 64 with a sprocket 66. The shaft 54 has a cooperating sprocket 68 and a chain (not shown) interconnecting the sprocket 66 and 68 enables the drive shaft 54 to be turned by the motor 62.
The drive screw nut 52 is shown in cross-section in FIG. 3, and as illustrated, is threaded on the drive screw 54. It has a horizontal longitudinal bore for receiving the drive screw 54, and has interior threads which cooperate with the screw threads on the drive screw 54. The drive screw nut cooperates with the ways 50 as described above in connection with FIG. 4, and so is constrained for movement along the axis of the drive shaft 54 as the latter is rotated.
A gear housing 70 is mounted in sliding relationship with the drive screw nut 52, the latter being received in a horizontal bore passing through the gear housing. A spring 72 urges the housing to its leftward position as illustrated in FIG. 3, the spring 72 being trapped between the rear wall of the gear housing, and an upstanding flange 73 provided on the drive screw nut 52. A bolt 74 is threaded into the housing 70 and passes through an aperture in the flange 73. The head of the bolt limits leftward movement of the gear housing relative to the drive screw nut, and retains the spring 72 in position.
A horizontal shaft 76 is supported by the gear housing and a gear 78 is mounted on the shaft for rotation therewith. A latch 80 is fixed to the gear 78 and turns therewith. The gear 78 cooperates with a rack 82 formed in the upper surface of the left end or forward end of the drive screw nut 52, so that as the drive screw nut 52 is moved leftwardly (as shown) relative to the gear housing, the gear 78 is rotated in a clockwise direction, thereby to lift the latch 80. In operation, the latch 80 engages a hook on a pallet in the position shown in FIG. 3, and the motor 62 causes the screw 54 to rotate, and bring the drive screw nut 52 and the gear housing 70 rightwardly, thereby pulling the pallet onto the rotatable pallet shuttle. The index table is then rotated to the correct position, and the motor 62 energized in its reverse direction, whereby the drive screw nut 52 and the gear housing 70 are moved leftwardly, loading the pallet into position relative to the machine tool, or alternatively, returning it to a pallet storage position. The spring 72 is sufficiently strong to maintain the separation between the drive screw nut 52 and the gear housing 70.
When the leftwardly moving gear housing 70 reaches a fixed stop 83, further rotation by the drive screw 54 acts to compress the spring 72 and move the drive screw nut 52 leftwardly relative to the gear housing. This causes a rack 82 to engage and rotate the gear 78, thereby lifting the latch 80, and freeing the rotating pallet shuttle from the pallet tongue or key. The pallet shuttle can then rotate to the next pallet position, and when this position is reached, initial rightward movement of the drive screw nut 52 lowers the latch 80 into latching position, after which a new pallet may be pulled toward the center of the rotating shuttle.
It can be seen that the movement sequence, including latching and unlatching, is completely automatic and sequential, and does not require any limit switches, sequence controls or the like. Means are provided, however, for sensing when the drive screw nut is reaching one of its two end positions, so that the feed speed can be lowered before the moving members are finally stopped.
Projecting rearwardly from the forward wall 83 is a shaft 86, and a corresponding shaft 88 projects forwardly from the rear wall 56. A tube 90 is mounted in sliding engagement on the shafts 86 and 88, so they may slide longitudinally while being supported for such movement by the shafts 86 and 88. A spring 92 is mounted inside one end of the tube 90, with one end of the spring 92 in engagement with the outermost surface of the shaft 86, and the other end abutting an interior ledge 96 within the tube 90. A spring 94 is received in similar fashion at the other end of the tube 90, with one end engaging the free end of the shaft 88, and the other end abutting a ledge 98. The two springs 92 and 94 serve to maintain the tube 90 in a normal central position, corresponding to equal compression of the two springs 92 and 94. This is the position illustrated in FIG. 3.
Two cams 102 and 103 are mounted on the tube 90, and cooperate with switches 108-110, mounted on a bracket 111. A cam follower 112 is adapted to be operated by the cams 102 and 103 in response to shifting movement of the tube 90. The cam follower 112 is mounted in a vertical orientation below the tube 90, and is biased upwardly by a spring 113. Its lower end is attached to an actuator 117, which is adapted to deactuate switch 109 by its initial downward movement, and then actuate switch 108 by further downward movement. In the position illustrated in FIG. 3, the switch 109 is energized, indicating a generally central position of the tube 90.
A collar 107 is provided on the tube 90 near its left-hand end, and a corresponding collar 114 is provided on the tube 90 near its right-hand end. The collar 107 is adapted to engage a depending portion 119 of the drive screw nut 52, so that leftward movement of the drive screw nut from the position shown in FIG. 3 carries the collar 107 and the tube 90 leftwardly, as the spring 72 is compressed. This movement of the shaft 90 causes the switch 109 to first be deactuated, by virtue of the cam 103 moving relative to the cam follower 112, forcing it downwardly. The signal produced by the switch 109 can be used to slow the feed speed of the motor 62, preparatory to stopping the parts. Further leftward movement of the drive screw nut 52 continues to carry the tube 90 leftwardly, until the higher part of the cam 103 forces the cam follower 112 further downward, causing the actuator 117 to operate the switch 108. The switch 108 is operated when the latch 80 has been lifted through an angle of about 70° or 80°. The signal from the switch 108 can be used to stop the motor 62 when the latch 80 has been lifted sufficiently to clear the tongue or key of the pallet.
When a pallet is being loaded onto the rotating pallet shuttle, the drive screw 52 moves rightwardly, thereby lowering the latch 80 into position, and the tube 90 also moves rightwardly, in response to the force of the spring 92. The switch 108 becomes unactuated immediately upon rightward movement of the shaft 90, and the switch 109 becomes actuated when the shaft 90 reaches the position shown in FIG. 3, with the latch 80 lowered to latching position as shown. The deenergization of the switch 109 supplies a signal which can increase the feed speed of the motor 62, so that the pallet may be rapidly loaded onto the rotating carousel. Further rightward movement of the pallet brings the depending portion 119 of the drive screw nut 52 into conjunction with the collar 114, and moves the tube 90 rightwardly, first deactuating the switch 109, as the follower moves off of cam 103 and ultimately actuating the switches 108 and 110 via cam 102 and follower 112, when the drive feed screw 52 approaches and reaches its extreme right position. The signal from the switch 109 can be used to reduce the feed speed, preparatory to stopping the motor 62 the instant at which the switch 110 becomes actuated. The signal from the switch 108 is not used in this mode of operation. The switch 110 is not operated during leftward movement because of the reduced size of the cam 103 relative to the cam 102. It is apparent from FIG. 3 that these functions can take place with only three limit switches 108-110 all mounted close to each other, which simplifies the electrical wiring of the apparatus.
FIG. 5 is a plan view of the apparatus illustrated in FIGS. 3 and 4, showing the latch 80 in lowered or latching position. The ways 50 supports the sliding movement of the drive screw nut 52 and the ways 112 are provided for accommodating the sliding movement of the pallet onto the rotating pallet shuttle.
FIG. 6 illustrates a vertical cross-section through the center of the pallet 115, and FIG. 7 shos its plan view. The pallet has a central bushing 121 with a vertical aperture, which is adapted to permit precise location of parts relative to the central position of the axis. A hook or tongue member 116 projects from one end of the pallet, and is located a precise distance from the center of the bushing 121, so that the pats which are located relative to bushing 121, may also be located relative to the tongue 116.
The horizontal upper surface of the pallet has a relatively thick wall 118, and is further strengthened by downwardly depending ribs 120, which run along the bottom for the length of the pallet. The two intermediate ribs 120 are provided with surfaces for engaging the ways 112 of the rotating pallet shuttle, so that the vertical position of parts located on the pallet 115 is also known with precision.
FIGS. 8 and 9 illustrate the side and end elevations of an extension wing 130 which forms one of the pallet storage stations. The wing 130 is composed of a pair of side walls 132 and 133, bottom wall 26 and a top wall 136 secured by welding or the like to the side walls 132. The bottom wall 26 is bolted by the bolts 34 to the support 33 (FIG. 2), at one end of the upper wall 136, and the other end of the upper wall, as well as the side walls 132 and 133, is supported by a support member 138, the lower end of which rests on the floor or other support member. A drip pan 139 covers the upper surface of the top wall 136, and the ways 28 are supported by the upper wall 136, above the drip pan 139. The ways include a pair of rails 140, and a pluraltiy of rollers 142 are mounted on the upper surface of the rails 140, and a further pluraltiy of rollers 144 are mounted on the outside horizontal surfaces of the rails 140. The rollers 142 and 144 guide the movement of the pallet 115, so that it is allowed to move in a rectilinear direction when the hook or tongue 116 is pulled forward by the rotating pallet shuttle. Each of the rollers 142 and 144 is mounted on a shaft, so that it can rotate relative to the rails 140 on which it is mounted.
From the foregoing, the apparatus of the present invention has been described in terms of a preferred embodiment. It will be apparent to those skilled in the art that various modifications and additions may be made in the apparatus of this invention without departing from the essential features of novelty thereof which are intended to be secured and defined by the appended claims. | 4y
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BACKGROUND OF THE INVENTION
This invention broadly relates to a novel lubricant spraying apparatus for use in metal forming and glassware forming machines. More particularly, the invention relates to a special spray ring apparatus used in such machines which includes a plurality of special nozzles which enable the fluid lubricant material to be sprayed into the cavity of the forming machine such that the interior surfaces of the cavity are uniformly and properly coated with the lubricant.
In the past there have been numerous problems in metal forming and glassware forming machines caused by the fact that the forming cavities utilized therein were not properly coated with the lubricant material which is conventionally used therein to provide lubricating and release agent properties to the cavity during the forming operations therein and, for release of the part after the forming operation has been completed. Such problems are highly significant in that improper lubricant coating can lead to highly serious distortions, deformations, improper configurations, etc. in the part being formed in the cavity.
The state of the art is indicated by the following U.S. patents: Hamilton U.S. Pat. No. 3,580,711; Duggan U.S. Pat. No. 3,508,893; Colchagoff U.S. Pat. No. 3,536,468; Keller U.S. Pat. No. 3,623,856; Keller U.S. Pat. No. 3,141,752; Renkl U.S. Pat. No. 3,801,299; Lichok et al. U.S. Pat. No. 3,480,422; Havens et al. U.S. Pat. No. 3,186,818; and British Pat. No. 1,349,121.
Accordingly, it is a primary object of this invention to provide a new lubricant spraying apparatus for use with metal forming and glassware forming machines.
Another object of the invention is to provide a new spray ring apparatus for use with either metal forming or glassware forming machines wherein said spray ring apparatus includes special nozzle means which are operative to spray a fluid lubricant material into the forming cavities of said machines in a unique manner such that the lubricant material is generally uniformly coated on the desired interior surfaces of the forming machine.
Other objects, features and advantages of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a spray ring assembly in accordance with the invention;
FIG. 2 illustrates a cross-sectional view taken along the line 2--2 in FIG. 1;
FIG. 3 illustrates a top or plan view of the spray ring shown in FIGS. 1 and 2;
FIG. 4 illustrates a cross-sectional view taken along the line 4--4 in FIG. 3;
FIG. 5 illustrates a sectional view taken along the line 5--5 in FIG. 3; and
FIG. 6 illustrates usage of the spray ring of FIG. 2 in association with a metal forming machine.
SUMMARY OF THE INVENTION
Briefly stated, the present invention concerns a lubricant spraying apparatus for metal forming and glassware forming machines of the type having a forming cavity into which the material to be formed is placed, and a plurality of nozzle means arranged to discharge fluid lubricant into the cavity prior to each forming operation such that the walls of the cavity and parts associated therewith in the forming operation are properly coated with the lubricant, said apparatus being comprised of, a spray ring means which is positioned generally around the opening of the cavity, said plurality of nozzle means being positioned on the spray ring and being operative to discharge fluid lubricant into the cavity in a helical tangential flow pattern, and conduit means for connecting the nozzle means and spray ring means to a source of fluid lubricant whereby a predetermined amount of lubricant can be supplied to the cavity at desired intervals of operation.
DESCRIPTION OF THE INVENTION
Referring now to the drawings, FIGS. 1 through 5 illustrate the spray ring 10 in accordance with the invention. FIG. 6 illustrates the spray ring 10 in position on a metal forming machine 12 adjacent the top thereof and near the cavity 14 within which metal parts are formed. It is to be understood, however, that the invention is equally applicable to glassware forming machines.
The spray ring 10 is typically formed of metal and fits on top of a die cavity designated 14. For ease of illustration in FIG. 6, the spray ring 10 is shown in loose fitting engagement with the machine 12 near the top of the cavity 14, whereas, in actual practice the spray ring 10 would be in press fitting engagement with the top surface of the machine 12. In typical use of the spray ring 10 a lubricant composition and air mixture enters through the tubing or conduit means designated 20 and from there it travels around a grooved ring or manifold portion designated 22. The manifold has a top surface designated 23 (FIG. 2). The lubricant mixture then leaves the manifold 22 and enters the die cavity 14 at tangential nozzle openings designated 24. As the lubricant mixture leaves the spray ring 10 through the nozzle openings 24, the specially designed nozzles 24 create a tangential spray pattern for the atomized or fluidized lubricant air mixture, with the spray pattern or flow pattern of the lubricant being shown by the helical path designated 26 shown in FIG. 6. It is to be noted that each of the nozzle openings 24 has a top surface designated 25 (FIG. 2).
The spray ring 10 as shown in the drawings contains four of the nozzle openings designated 24 and the tangential spraying of the lubricant mixture into the cavity causes what may be described as a helical or circular flow pattern to occur and the lubricant travels down into the die cavity 14 and deposits a uniform coating on the walls of the cavity. In addition, the knock out pin 28 (FIG. 6) which, for example may be spring loaded to be depressed downwardly to the bottom of the cavity 14 when the metal slug is inserted into the machine for the forming operation, is also coated with the lubricant mixture in a uniform manner. The forming tool 30 shown in FIG. 6 is the tool which is used to punch down into the cavity at a high operating speed for the purpose of forming the metal part which is inserted into the cavity for the forming operation.
Machines of the type shown in FIG. 6 typically operate at very high speeds, for example, with approximately one part per second being formed in the machine. It is extremely important in the operation of such machines that the cavity be properly coated with lubricant mixture such that the parts being formed at the high operating speeds do not have distortions, bends, disconfigurations and the like, in the part being formed, as a result of the cavity 14 being improperly or nonuniformly coated with lubricant.
In accordance with the preferred aspects of the invention, it is usually desired that three or more of the special nozzle means designated 24 should be used, however, it is apparent that in some installations only two such nozzle openings may be required, whereas in other installations a plurality considerably higher than three of such nozzle openings may be desired.
The spray ring assembly designated 10 has been used under actual operating conditions in the forming of parts, such as the forming of valves for automobile internal combustion engines. The usage of the spray ring 10 in accordance with the invention under such actual operating conditions has been highly successful in preventing distortions, disconfigurations, scorching and the like in the formation of such metal parts.
Other aspects of the spray ring 10 are constituted by the counter sunk holes designated 40 which may be used to fasten the spray ring in position on the forming machine 12. Other means of fastening or holding the spray ring may, of course, also be used. In addition, it is to be understood that the spray ring 10 as shown in operating position on the machine 12 in FIG. 6 may also be suitably mounted such that the spray ring 10 can be pivoted or lifted in an out of position adjacent the top of the cavity 14 at desired intervals of operation of the machine. This may be accomplished, for example, by using a pivoting mechanism and flexible conduit for attachment to the tube 20 as will be understood by those skilled in the art. In addition, if desired the circular edge opening at the top of the cavity 14 may be champfered or beveled slightly to assist in the desired tangential flow pattern for the lubricant.
While the invention has been described with reference to a metal forming machine, the invention is also applicable to glass forming machines or even to plastic molding processes wherein lubricant spraying devices are conventionally used. It will be apparent that the preferred embodiments of the invention disclosed herein are well calculated to fulfill the objects above stated, and it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims. | 4y
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FIELD OF THE INVENTION
[0001] This invention relates to the bonding of non-reactive fibers such as fiberglass fibers to steel or other metals, and to metal-hybrid composite articles made by such methods. Chemical bonding of the fiberglass fibers to a steel surface prepares the steel article for bonding with a carbon composite material. The resulting metal-composite hybrid articles are strong, durable, and resistant to damage from mismatches in coefficients of thermal expansion.
BACKGROUND OF THE INVENTION
[0002] Conventionally, when manufacturing metal-hybrid composites, attachment of non-reactive fibers to metals is an important issue. For materials used at temperatures below 250° C., adhesives are readily available. For metal-hybrid composites being used at higher use temperatures, however, off-the-shelf adhesives are not generally satisfactory.
[0003] There are extensive publications concerning various methods of bonding reactive fibers to metals. The following publications, some of which disclose such methods, constitute background for the present invention: U.S. Pat. No. 6,698,645 B1, entitled ‘Method of Producing Fiber-Reinforced Metallic Building Components’; US 2008/0011756 A1, entitled ‘Liquid Tight Sealing of Heat-Insulating Walls of a Liquified Natural Gas Carrier’; U.S. Pat. No. 6,922,517 B2, entitled ‘Quickly Bonding Optical Fiber Anchor Device Permitting Fibers to Remain Linear’; U.S. Pat. No. 5,288,354, entitled ‘Method of Bonding Self-Lubricating Fibers to an External Surface of a Substratum’; EP 1 153 698 A1, entitled ‘Article Comprising Creep-Resistant and Stress-Reducing Solder’; US 2005/0039836 A1, entitled ‘Multi-Component Fibers, Fiber-Containing Materials Made from Multi-Component Fibers and Methods of Making the Fiber-Containing Materials’; and US 2007/0235126 A1, entitled ‘Bonding of Carbon-Carbon Composites Using Titanium Carbide’.
SUMMARY OF THE INVENTION
[0004] The present invention provides a method for chemically bonding fiberglass fibers to steel surfaces in order to prepare the steel for bonding with carbon composite material. This fiber-bonding step greatly increases the strength of the subsequent metal-composite bond. The fiberglass fibers that are chemically bonded to the steel in accordance with the present invention provide a high surface area interface to entangle with carbon fibers in the composite component. This approach inhibits crack formation on the boundary surface between steel and composite components when they are bonded together.
[0005] The present invention uses a combustion-based method to bond non-reactive fibers such as fiberglass to steel or other metals. This invention uses three layers of carefully selected reactive material to create a functionally graded bond that is strong, durable, and resistant to damage from coefficient of thermal expansion (“CTE”) mismatches. After the fiberglass fibers are bonded to the metal, one may then “wind” the metal skeleton with glass fiber or carbon fiber. A next step would be to infuse and mold with phenolic or with epoxy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] These and other aspects and features of embodiments of the invention will be better understood after a reading of the following detailed description together with the accompanying drawings. The drawings are presented solely in order to illustrate the invention, and are not intended to be limiting thereof.
[0007] FIG. 1 schematically illustrates the use of three layers of materials to bond steel to glass fibers.
[0008] FIGS. 2A-2C schematically illustrate a metal/composite piston housing manufactured with a steel skeleton that provides bolt holes. FIG. 2A shows the steel skeleton. FIG. 2B shows the carbon composite in place “transparently” surrounding the steel skeleton, with the skeleton being shown within the carbon composite overlayer. FIG. 2C shows the same view as FIG. 2B , but in FIG. 2C the composite is not transparent.
[0009] FIG. 3 schematically illustrates a steel-carbon composite hybrid article.
DETAILED DESCRIPTION OF THE INVENTION
[0010] This invention uses three layers of materials to bond steel to fiberglass fibers (see FIG. 1 ). The reaction in accordance with the present invention must be carried out at a temperature which is high enough to bond the fiberglass fibers to the steel. It is also important, however, that the reaction temperature is not so high that is melts the fibers. Persons skilled in the art know, or can readily determine, appropriate temperatures for particular materials employed in the practice of the invention. Reaction parameters—such as the temperature employed, the quantity of reactants, and so on—are determined empirically based on the size and geometry of the part being bonded to the fiberglass fibers.
[0011] The layer adjacent to the steel is composed of a mixture of titanium powder, nickel powder, and carbon particles. These are preferably fine powders, as described in US 2007/0235126, the disclosure of which is incorporated herein by reference. A typical molar ratio of Ti:C:Ni in this layer is 1:0.7:0.5, although persons skilled in the art can readily determine other suitable molar ratios for these ingredients. The layer of initial powder mixture is typically from 1 to 3 millimeters in thickness. This layer will react with sufficient energy to melt iron and bond to the steel as it forms titanium carbide/nickel composite.
[0012] The intermediate layer is composed of nickel powder and aluminum powder. A typical molar ratio of Ni:Al in this layer is 1:1, although persons skilled in the art can readily determine other suitable molar ratios for these two ingredients. This layer provides a low ignition temperature (660° C.) to the three-layer system. The layer of initial powder mixture is typically from 1 to 3 millimeters in thickness. When this layer ignites, it will generate sufficient heat to make the first layer also react, also exothermally, and create an inter-metallic nickel/aluminum composite.
[0013] The top layer is composed of alumina powder with ends of the fiberglass fibers pressed against it. Fiberglass fibers used in the present invention typically have diameters in the range 10-100 microns. Typically, there will be from 10 2 to 10 5 fiberglass fibers per square centimeter in the bonding layers of the present invention. The fiberglass fibers can be provided by any suitable method. For instance, a fiberglass fabric having fiberglass fibers perpendicular to its surface can be pressed into the aluminum layer. The layer of alumina and fiberglass fibers is typically from 1 to 5 millimeters in thickness. Neither the fibers nor the alumina are reactive under the processing conditions used in the present invention. However, the alumina is heated and melts as a result of the heat generated by the two layers described above. The molten alumina wets the fiberglass fibers and bonds to them. It is noted that fiberglass fibers comprise silicon dioxide.
[0014] The liquid aluminum also bonds to layer 2 , and layer 2 bonds to layer 1 , as illustrated in FIG. 1 . The resulting thickness of the join is typically less than 1 millimeter.
[0015] FIG. 3 schematically illustrates a steel-carbon composite hybrid article in which the bond between the steel and the carbon composite is a cermet (having three layers as described above) to which is adhered glass fibers which facilitate extremely strong bonding between the cermet-coated steel inner part and the carbon composite housing. It should be noted that the depiction in FIG. 3 is not to scale. The thickness of the join is typically less than 1 millimeter.
[0016] In accordance with the present invention, this three-layer system is ordered according to the coefficients of thermal expansion (“CTE”) of the materials selected for the layers, in order to avoid de-bonding due to CTE mismatches. Indeed, in the above example, the graded changing of aluminum concentration between layers 2 and 3 and of nickel concentration between layers 2 and 1 provides graduated change of CTE through the joining layer. See FIG. 1 .
[0017] The present invention is especially suitable in the manufacture of metal/composite constructs, in which critical features such as bolt holes are made of metal and much of the remainder of the construct is made of carbon composite.
[0018] For instance, as illustrated in FIGS. 2A-2C , a metal/composite piston housing can be manufactured with a steel skeleton which provides bolt holes. Employing the process of this invention, the steel skeleton, illustrated in FIG. 2A , is bonded into a carbon composite housing which serves to hold the steel skeleton in place, to facilitate its manipulation during assembly of the complete piston housing, and to protect it from damage by the environment in which it will be used. FIG. 2B conceptually illustrates the carbon composite in schematic form so as to facilitate understanding of the manner in which it surrounds the piston housing skeleton. FIG. 2C shows a realistic view of a finished product made in accordance with the present invention. The surface of the FIG. 2C piston housing is primarily composite, but steel bolt hole protrude through the composite to permit access to the bolt holes.
[0019] Another type of final product construct that can be made in accordance with the present invention is high performance wheels, for instance, aircraft nose wheels and wheels for race cars and high end automobiles. In these wheels, the bolt holes for receiving the lugs would be present on a metal (e.g., magnesium alloy) skeleton, and the remainder of the wheel would be made of carbon composite.
[0020] The present invention has been described herein in terms of several embodiments. However, modifications and additions to these embodiments will be apparent to those skilled in the relevant arts upon a reading of the foregoing description. It is intended that all such obvious modifications and additions form a part of the present invention to the extent that they fall within the scope of the several claims appended hereto. | 4y
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains to naturally-occurring insulin mediators, and in particular, two purified insulin mediators obtained from liver tissue. Additionally, a process for purification of the naturally-occurring substances is provided, together with a screening test for the detection of the diabetic state. Related artificial compounds can be similarly prepared
2. Background of the Prior Art
Numerous researchers have established that insulin, a major anabolic hormone, which plays a central role in the control of metabolism of carbohydrates, fats and proteins, acts indirectly, through the activity of a plurality of insulin mediators, that apparently link the hormone, and a variety of regulating enzymes. Thus, Larner, Diabetes, 21, page 428 (1972) suggested the existence of an insulin mediator blocking the activation of cyclic AMP-dependent protein kinase Subsequently, Jarett et al, Science 206, pages 1407-1408 (1979) confirmed the activation, by the proposed mediators, of PDH in adipocyte mitochondria. Subsequently, Mato et al, Journal of Biological Chemistry 262, pages 2131-2137 (1987), and Saltiel et al, Proceedings of the National Academy of Science 83, pages 5793-5797 (1986) have identified insulin "modulators", similar to glycosyl-phosphoinositol linkers known to anchor proteins to the external surface of cell membranes.
Thus, substantial evidence has been provided that there exists a plurality of insulin mediators which operate in conjunction with specific enzymes, in the multiple functions of insulin. There are at least suggestions that one or more of these mediators is derived from traditional glycosyl-phosphoinositol linkers, similar to known anchor proteins.
Effective identification and treatment of the diabetic state, and other functions controlled or impacted by insulin, may be most effectively carried out through the mechanism of insulin mediators. U.S. Pat. No. 4,446,064, Larner et al, discloses a partial purification process for the isolation of an insulin mediator substance derived from muscle tissue, the isolated fraction having the ability to inhibit protein kinase However, the purification system provided therein is incomplete, and the structure of the mediator collected in the obtained fraction is not identified. Effective in vivo treatment of diabetes, and related insulin conditions, as well as the use of the mediators as diagnostics, requires high degrees of purification of mediator substances. Additionally, production of large amounts of the mediator substance, preferably through synthetic or biological means, requires identification of structure information concerning these mediators.
Accordingly, it remains an objective of the art to provide a highly purified insulin mediator, a system for purification of the same, and the structure of the insulin mediator, for the more effective treatment of insulin-resistant conditions.
SUMMARY OF THE INVENTION
At least two insulin mediator substances have been obtained in highly purified form from the liver of mammals, including rats, bovines and swine. The organism can either be directly injected with insulin, or the liver tissue collected therefrom be exposed to insulin, after homogenization of the liver tissue, to obtain the membranes thereof The collected liver tissue is treated with acid, if the liver tissue membrane is exposed to insulin, to stop the incubation, and both types of liver tissue are subsequently boiled to denature the proteins present Denatured protein is removed by centrifugation and the remaining supernatant is purified by charcoal adsorption, to remove nucleotides, such as ATP, ADP and AMP. The deproteinized, charcoal-purified material is adsorbed onto an anion exchange resin, and eluted with dilute HCl. Two separate fractions are obtained, the first at a pH of 2.0, and the second at a pH of 1.3-1.5.
The separate fractions are subsequently introduced to sizing columns. The pH 2.0 fraction is exposed to a sizing column such as P4, while the pH 1.3-1.5 fraction is run through a G10 or similar, sizing column. Such sizing columns are conventionally used to remove inorganic salts, and their use is the same herein. The fractions collected are lyophilized, and redissolved in minimal volumes of water. The pH 2.0 fraction, is activated by adsorption onto a cation exchange resin column, such as a chelex resin column. The fraction is eluted with 1 N HCl. The chelex column appears to activate this fraction, giving an increase observed in the activation of pyruvate dehydrogenase, in vitro studies, of about 5-fold.
The eluted material is again chromatographed on sizing columns, and after recovered from the sizing columns, subjected to three successive thin layer chromatography purification steps (TLC 1-3). TLC 1 employs a solvent system of n-propanol and water, TLC 2 employs a solvent system of ethylene glycol monoethlyether, propionic acid, water, and TLC 3 employs a quaternary system, isopropanol, pyridine, acidic acid and water.
The fraction recovered from the TLC solvent systems is passed through a sizing column, the fraction recovered, after removal of insolubles, being essentially homogeneous. The relative purity of the recovered fractions is well above 80%, and may be as high as 90%, or better.
TLC 3 can also be used as a an analytical tool to confirm the presence of the mediator Presence of the mediator in the isolated fraction in TLC 3 gives a characteristic salmon-colored spot when the plate is treated with ninhydrin stain, quite distinct from the characteristic purple color normally produced.
Various synthetic analogues of the natural materials may be based on characteristics of the natural material structures, to reduce synthesis obstacles.
DETAILED DESCRIPTION OF THE INVENTION
The insulin mediator fractions that are the focus of this invention are derived from liver tissue While it is believed that similar mediator substances are found in other tissue systems, the mediators are collected in the greatest quantity from the liver material of mammals, and accordingly, prior to a synthetic or biological production system, this is the best source for recovery.
The mammalian liver source may be exposed to insulin either by direct injection of the mammal, or by exposure of the liver membrane tissue to insulin, in vitro. As an example, rats were injected with insulin (5 U/kg) via the tail vein. The rats are sacrificed after five minutes, with the livers being removed immediately and frozen in liquid nitrogen Alternatively, the liver tissue is homogenized and the membranes obtained by centrifugation. Membrane collected is incubated together with insulin (1 mu/ml in a pH 7.4 buffer system further containing ATP, Mn 2+ , BSA, PMSF and aprotonin). The incubation is terminated by the addition of formic acid, or similar acid, to a pH of 3.5. The material obtained through either method is boiled, so as to denature existing proteins The denatured proteins can be removed by gross filtration methods, or centrifugation. The recovered material is further purified by adsorption onto charcoal, to remove major nucleotides such ATP, ADP and AMP.
The resulting material, from which major protein and nucleotide fractions have been removed, is adsorbed onto an anion exchange resin and eluted One exemplary resin is an AGlX8 resin, although other anion exchange resins may be used, with similar results. The mediators are eluted with dilute HCl. Two separate fractions are eluted, the first at a pH of about 2.0, the second at a pH of about 1.3-1.5. In general, both fractions will receive similar subsequent processing. However, because of the different nature of the two fractions, different sizing columns will generally be used. Unless indicated to the contrary, it should be understood that both fractions are subjected to the same purification procedure.
The recovered, eluted pH 2.0 fraction is adsorbed onto a cation exchange resin, such as a chelex resin. Elution therefrom with 1 N HCl gives a sharp increase in PDH-activating activity observed in vitro, on the order of a 5-fold increase. It should be noted that the use of a cation exchange resin, such as the chelex resin, is essential to achieve this marked increase in activation. Such resins are conventionally used for the removal of trace amounts of heavy metals.
Both fractions are purified to essential homogeneity through thin layer chromatography, after repeated lyophilization and sizing, as necessary. In general, the pH 2.0 fraction and the pH 1.3-1.5 fraction can be purified on a sizing column such as P4 sizing column.
The recovered material is subjected to repeated thin layer chromatography. Although other formats may be used, silica plates were found to be most efficacious, the active material being recovered after each TLC phase by scraping, elution with distilled water, or HCl of appropriate pH, and repeated lyophilization. In TLC 1, a solvent system of n-propanol: water of 7:3 is employed. The eluted material is then subjected to TLC 2 using a ternary system of ethylene glycol monoethylether: propionic acid: water of proportions 70:15:15. Subsequently, in TLC 3, the remaining material is purified in a quaternary system, employing isopropanol: pyridine: acetic acid: water in proportions 8:8:1:4.
The resulting material is essentially pure, with TLC impurities remaining. These are removed through further sizing, and high performance liquid chromatography, employing typical HPLC columns, such as a GLYCO-PAK or BONDAPAK C18 HPLC column. Most effective purification can be achieved using a minimal volume of 0.1% TFA with elution of the material using the same substance, or a water equilibrated P2 column. Beef or pork liver can also be used to prepare mediator by similar methods.
It should be noted that the mediator, if present, gives a unique and easily recognized signature in the TLC 3 solvent system, upon application of a ninhydrin stain. The salmon-color spot obtained is easily and quickly recognized. This qualitative recognition step offers an effective analytical tool, as well as a purification medium. Thus, one practicing the purification system described above, can quite quickly screen a donor substance so purified for the presence of the mediators. Absence of the mediator may be indicative of the diabetic state. Thus, as applied to mammals, including humans, a tissue sample taken, and treated with the above purification system through the TLC 3 step, can be quickly screened. Absence of the characteristic of the salmon-colored spot suggests the individual should be further tested, for confirmation of the diabetic indication As this would be a screening process only, those of skill in the art will recognize that the activation treatment on the cation exchange resin, such as a chelex resin, described above, can be dispensed with, as this is essentially an activation step.
Material treated according to the above process has analyzed for structure, by gas chromatography/mass spectroscopy, and associated analytic techniques. GC analysis indicates the presence of mannose, D-chiroinositol and galactosamine in the pH 2.0 mediator. Additional analysis indicates the mediator to be an anchor-type protein of the approximate structure represented below: ##STR1##
It is presumed that, when intact, the fatty acid terminal portion is linked to the cell membrane of the organism. Certainly, such phosphate linkage opportunities occur in virtually all mammalian cell membranes, and accordingly, the active unit is believed to begin with the inositol grouping Further analysis has confirmed the structure of the mediator fractions as follows.
The pH 2.0 fraction, having the biological property of activating pyruvate dehydrogenase for the formation of acetyl-CoA from glucose, has been analyzed as having a chiroinositolhexosamine disaccacharide, linked to the glycol fatty acid through a phosphoester linkage. An additional carbohydrate moiety, probably comprised of 1-3 mannose units are linked through a phosphoester-ethanolamine bond to an amino acid linkage to a protein, in vivo.
While reproduction of the entire structure will of course give a biologically active compound, extended carbohydrate synthesis is difficult. Biologically active compounds would include synthetic compounds capable of activating pyruvate dehydrogenase in vivo. Typically, these comprise the disaccharide component D-chiroinositol/hexosamine together with extender units, typically by hydrocarbon units, terminating in a hydroxyl group for the phosphoester linkage.
Similarly, the pH 1.3-1.5 mediator has the characteristic biological activities of inhibiting both a cAMP kinase and adenylate cyclase. Analysis shows this mediator to have a myoinositol/hexosamine disaccharide, followed by 3 mannose units bearing galactose side chains. Again, a synthetic substitute would have at least one of these biological activities. Such analogues include the myoinositol/hexosamine disaccharide and 1-3 mannose units, with appropriate linkage units Again hydrocarbon extenders may be used in place of carbohydrate units if necessary. Work is currently underway to determine whether or not addition of vanadate or diacyglycerol compounds to the mediator can achieve glucose transport characteristics, to duplicate the effects of insulin. When resolved, such studies should result in improved pharmaceuticals for the treatment of diabetes The mediators, as purified, offer a tremendous resource in the screening and diagnosing of the diabetic state, as well as materials for the preparation of insulin-like pharmaceuticals for the treatment of specific conditions associated with diabetes.
The invention addressed herein has been described both generally and by example above. Those of skill in the art will recognize that the exemplary recitations are not intended to limit the invention, and that substitution and derivation can be practiced, without departing from the scope of the invention. In particular, heat and time parameters, as well the identity of various resins used for purification, can be altered, without inventive effort. Such substitutions do not depart from the scope of the invention. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. | 4y
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RELATED APPLICATION
This application is a continuation of U.S. patent application Ser. No. 11/421,043, filed May 30, 2006, now U.S. Pat. No. 7,620,626, which is a continuation of U.S. patent application Ser. No. 10/117,701, filed on Apr. 4, 2002, now U.S. Pat. No. 7,593,920, which claims priority to U.S. Provisional Application 60/281,340, which was filed on Apr. 4, 2001, all of which are incorporated herein by reference.
COPYRIGHT NOTICE AND PERMISSION
A portion of this patent document contains material subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyrights whatsoever. The following notice applies to this document: Copyright© 2001, West Group.
TECHNICAL FIELD
The present invention concerns systems, methods, and software for identifying and associating documents relevant to an input document, especially judicial decisions that are related by case history to other judicial decisions.
BACKGROUND
The American legal system, as well as some other legal systems around the world, relies heavily on written judicial opinions—the written pronouncements of judges—to articulate or interpret the laws governing resolution of disputes. Each judicial opinion is not only important to resolving a particular legal dispute, but also to resolving similar disputes, or cases, in the future. Because of this judges and lawyers within our legal system are continually researching an ever-expanding body of past opinions, or case law, for the ones most relevant to resolution of new disputes.
To facilitate these searches, companies, such as West Publishing Company of St. Paul, Minn. (doing business as West Group), collect and publish the judicial opinions of courts across the United States in both paper and electronic forms. Many of these opinions are published with bibliographic cites or hyperlinks to historically related opinions, known as prior cases, from other courts that have previously ruled on all or part of the same dispute. The cites and hyperlinks enable researchers to find printed volumes containing the related opinions or readily access the related opinions electronically over a computer network. For example, an opinion in a patent case from the United States Supreme Court, the highest court in the United States, would generally cite not only an opinion from the Court of Appeals for the Federal Circuit, the next highest court for patent cases, but also an opinion of a local Federal District Court where the patent case started, thus documenting the history or progression of the case through the U.S. federal judicial system.
Although it may seem a simple matter to identify the prior cases for any given case, the reality is that identifying these cases is problematic for at least three reasons. First, the vast majority of opinions (about 90%) as originally written do not explicitly identify their prior cases, in part because some prior cases are only published after the opinions that should cite them were published. Second, there are no straightforward rules based on the court titles to determine even when to look for prior cases, since appellate courts—courts that review the decisions of other courts—sometimes hear new cases, and trial courts—courts that hear new cases—sometimes re-decide old cases that have been remanded (sent back) from appellate courts. And third, even when one knows to look for a prior case, the conventional technique of computer-based text-matching (that is, searching existing opinions for those with court dockets, case title, and party names that match those in a given case) not only suggests too many non-prior cases, but also misses too many actual prior cases, creating additional work for human reviewers without necessarily improving accuracy.
Accordingly, the present inventors have recognized a need for new tools and methods to facilitate identification of historically related cases, and potentially other types of related documents.
SUMMARY OF EXEMPLARY EMBODIMENT(S)
To address this and other needs, the present inventors devised systems, methods, and software that generally facilitate identification of one or more documents that are related to a given document, and particularly facilitate identification of prior cases for a given case. One specific embodiment extracts case information, such as party names, courts, dates, docket numbers, and history language, from an input case, retrieves and ranks a set of candidate cases based on the extracted party information, and compares one or more of the ranked cases to the input case using a support vector machine. The support vector machine—more generally, a kernel-based learning module—ultimately helps decide whether to link or recommend linking of the input case and one or more of the ranked cases.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a diagram of an exemplary document-retrieval-and-linking system 100 embodying teachings of the invention;
FIG. 2 is a flowchart illustrating an exemplary method embodied in system 100 ;
FIG. 3 is a facsimile of an exemplary graphical user interface 300 that forms a portion of system 100 .
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
This description, which references and incorporates the above-identified Figures, describes one or more specific embodiments of one or more inventions. These embodiments, offered not to limit but only to exemplify and teach the one or more inventions, are shown and described in sufficient detail to enable those skilled in the art to implement or practice the invention. Thus, where appropriate to avoid obscuring the invention, the description may omit certain information known to those of skill in the art.
The description includes many terms with meanings derived from their usage in the art or from their use within the context of the description. However, as a further aid, the following exemplary definitions are presented.
The term “document” refers to any addressable collection or arrangement of machine-readable data.
The term “database” includes any logical collection or arrangement of documents.
The term “case” refers to a legal dispute or proceeding and/or one or more associated documents, such as a judicial opinion.
The term “prior case” refers to a legal dispute or proceeding and/or one or more documents that are procedurally or historically related to one or more subsequent cases or associated documents.
Exemplary Document-Retrieval-and-Linking System
FIG. 1 shows a diagram of an exemplary document-retrieval-and-linking system 100 for automatically retrieving and linking (or suggesting linkage) of electronic documents, such as a given case and one or more prior cases. However, the present invention is not limited to any particular type of documents.
Though the exemplary system is presented as an interconnected ensemble of separate components, some other embodiments implement their functionality using a greater or lesser number of components. Moreover, some embodiments intercouple one or more the components through wired or wireless local- or wide-area networks. Some embodiments implement one or more portions of system 100 using one or more mainframe computers or servers.) Thus, the present invention is not limited to any particular functional partition.
System 100 includes a document database 110 , a citator database 120 , and a prior-case-retrieval processor 130 , a preliminary-decision database 140 , and work center 150 .
Document database 110 includes a collection of cases 112 or other documents related to legal disputes. Each case 112 includes a title and a body, such as title 112 . 1 and body 112 . 2 . In the exemplary embodiment, database 110 includes new, that is, recently published cases from a larger collection of cases in a main database (not shown). However, in other embodiments, the main database or multiple databases are used.
Citator database 120 includes approximately seven million index records, such as representative index records 122 , 124 , and 126 , for a set of existing cases in a main database (not shown). Each index record includes one or more indices, with some index based on a particular entity (person or entity) identified in the title of a case in the main database and other indices based on dates, jurisdiction, court name or identifier, and docket numbers. Some embodiments user other information from the document. Index record 122 includes indices 122 . 1 ; index record 124 includes indices 124 . 1 ; and index record 126 includes indices 126 . 1 .
In the exemplary embodiment, each record has up to eight indices for its associated case. The party-based indices result from parsing the titles of each case, extracting party entities from each parsed title, and assigning indices to each extracted party entity. Each party entity has its own set of indexing terms. For example, the entity “David E. Smith” has the indexing terms “Smith” and “David+Smith.” The generated terms are collated and their document frequencies (that is, the number of titles a term appears in) are computed and associated with the indices. Notably, smaller document frequencies suggest greater discriminating power of the term. If a case title contains more than eight person entities, the exemplary embodiment only indexes their last names because within a case, last name is a more likely reference than a first name. Table 1 below shows some sample titles and their associated index terms.
Case Title
Index Terms
City of Portland v. Montgomery
portland
montgome
Hoffman Plastic Compounds, Inc.
hoffman + compound
v.
hoffman + plastic
National Labor Relations Board
plastic + compound
compound
plastic
hoffman
nlrb
Arizona Corporation Commission
Court + maricopa
v.
az + comn
Superior Court of Maricopa County
maricopa + county
maricopa
superior + court
az
superior
court
Ritchie Grocery
Sherry + glass
v.
ritchie + grocery
Sherry K. Glass
ritchie
grocery
glass
Belcher (Carol)
Carol + belcher
v.
price + foundati
T. Rowe Price Foundation, Inc.
t + rowe
t + price
rowe + price
rowe
foundati
price
Carolyn J. Gibbs v. Ashley C. Gibbs, a
Ashley + gibbs
Minor Child, Andrew F. Gibbs, a
carolyn + gibbs
Minor Child
andrew + gibbs
v.
general + american
General American Life Insurance
american + life
Company
american
general
Coupled to both databases 110 and 120 is prior-case-retrieval processor 130 . Prior-case-retrieval processor 130 includes, in addition to conventional processors 130 . 1 and memory 130 . 2 (shown in lower right corner), various software and data components which can take a variety of forms, such as coded instructions or data on an electrical, magnetic, optical, and/or magnetic carrier medium. Arranged in the figure to show an exemplary software architecture, these components include a extraction module 131 , a search module 132 , a comparison module 133 , a support vector machine 134 , a decision maker 135 , and a decision-criteria module 136 . Prior-case-retrieval processor 130 is also coupled to preliminary-decision database 140 .
Preliminary-decision database 140 stores and/or organizes the output of prior-case-retrieval processor 130 , specifically prior-case candidates and/or other related information. Within database 140 , the prior-case candidates can be organized as a single first-in-first-out (FIFO) queue, as multiple FIFO queues based on single or multiple jurisdictions or subjurisdictions. The invention, however, is not limited in terms of database structure. The prior-case candidates are ultimately distributed to work center 150 .
Work center 150 communicates with preliminary-decision database 140 as well as database 110 (and the main database) and ultimately assists users in updating cases to include cross references and hyperlinks between one or more of the stored prior-case candidates and particular input cases. Specifically, work center 150 includes workstations 152 , 154 , and 156 . Workstation 152 , which is substantially identical to workstations 154 and 156 , includes a graphical-user interface 152 . 1 , and user-interface devices, such as a keyboard and mouse (not shown.)
In general, exemplary system 100 operates as follows. Database 110 receives or contains a set of one or more input cases, and prior-case-retrieval processor 130 determines whether one or more of the cases within citator database 120 are sufficiently related to any of the input cases to recommend their association or linking as prior cases to the input cases. (Some other embodiments directly associate or link cases rather than providing recommendations.) The recommended cases, or more precisely citations, are stored in preliminary-decision database 140 and later retrieved by or presented to editors at work center 150 via graphical-user interfaces in workstations 152 , 154 , and 156 for acceptance or rejection. In some embodiments, the input case and the accepted cases are cross-hyperlinked and cross-cited, and in other embodiments a prior-case field in a data record associated with the input case is updated automatically or manually to reflect newly identified prior cases. Data on the acceptance and rejections is fed back to prior-case-retrieval processor 130 for incremental training or tuning of its decision-criteria module 136 .
More particularly, FIG. 2 shows a flow chart 200 illustrating in greater detail an exemplary method of operating system 100 . Flow chart 200 includes a number of process blocks 210 , 230 , 240 , and 250 , which parallel components in system 100 . Though arranged serially in the exemplary embodiment, other embodiments may reorder the blocks, omit one or more blocks, and/or execute two or more blocks in parallel using multiple processors or a single processor organized as two or more virtual machines or subprocessors. Moreover, still other embodiments implement the blocks as one or more specific interconnected hardware or integrated-circuit modules with related control and data signals communicated between and through the modules. Thus, the exemplary process flow is applicable to software, firmware, hardware, and other types of implementations.
In block 210 , the exemplary method begins by receiving or retrieving an input case (or document). In the exemplary embodiment, this entails transferring an input case from database 110 to processor 130 . The input case may be a newly added case or an existing case. Exemplary execution then proceeds to block 230 .
Block 230 , generally representative of prior-case-retrieval processor 130 , includes blocks 231 - 235 . Block 231 , representative of actions of extraction module 131 , entails extracting one or more party entities from the input case. Specifically, one or more portions of the input case, such as a header containing case title, court name, and docket, are syntactically parsed to form well-formed-substring tables, using a variant of the Cocke-Younger-Kasami (CYK) parsing algorithm. (See, for example, Hopcroft and Ullman, Introduction to Automata Theory, Languages, and Computation, pp. 139-142 (1979), which is incorporated herein by reference.) The exemplary parser uses a set of conventional grammar rules and a lexicon of names, place nouns (country, state, city, town, etc.), and company words available through publicly available databases. From the well-formed-substring tables, party entities are extracted, scored, and recorded as canonical forms free of syntactic variations. In other words, different phrases representing the same entity, such as “David E. Smith” and “(Smith) David E.” map to an identical data structure.
More specifically, the exemplary embodiment extracts four types of party entities: people, companies, places, and agencies, with each extracted entity assigned a weight based on its discriminatory power. The exemplary embodiment allows company parties to contain persons or places, and agency parties to contain places; person and place parties may not include other parties. The exemplary embodiment assigns each party a weight based on its discriminatory power or the amount of information it contains. The weight is defined as
w = 1 N ∑ i = 1 N 1 log ( d f i + 1 ) ( 1 )
where N is the number of terms in a party entity, and df i is the number of case titles of a training collection that include the i-th term. Execution then proceeds to block 232 .
Block 232 , which represents operation of search module 132 , entails searching for prior-case candidates based the extracted information. In particular, it entails execution of process block 232 . 1 which generates one or more queries based on the extracted information, and execution of block 232 . 2 which retrieves cases from citator database 120 based on the defined queries.
In particular, block 232 . 1 defines or generates the queries using the party entities and other case information extracted from the input case. The indexing terms assigned to the party entities are sorted according to their document frequency, and then combined with the extracted date and court information to generate a set of structured queries. The court information includes the jurisdiction, agency, locality and circuit of the court. The input court information is used to select a set of possible prior courts according to the possible appellate chains for the instant court. The exemplary embodiments limits the search to cases decided in the past seven years.
More particularly, the exemplary embodiment generates a separate SQL query for each indexed title term extracted from the input case title. An example of SQL query for Oracle 8 (Oracle is believed to be a trademark of Oracle Corporation.) as used in the exemplary embodiment, is given below
SELECT case_number FROM Citator Database WHERE filed_date>add_months(trunc(to_date(‘08-DEC-1999’, ‘DD-MON-YYYY’), ‘y’), −84) AND index=‘william+polen’ AND jurisdiction_code=39 ORDER BY filed_date DESC;
In addition to these title-based queries, the exemplary embodiment generates a docket query for all cases in the database from a given jurisdiction and with a particular docket string. The docket string can be extracted from an appeal line in the text of the input case. The appeal line is a paragraph that indicated that that the input case is based on an appeal. One example is “This is an appeal from the district court . . . docket_string.” The majority of cases lack an appeal line, and the majority of those that include one omit a docket string. The system generates other queries using the dockets of the instant court and any docket found in the appeal line. However, other embodiments can use other types of query structures and systems. (Also, some embodiments can use other types of metadata such as markup language features, headers, address information, citations, etc.)
In block 232 . 2 , the generated queries are executed against citator database 120 , which as noted earlier includes party-based index structures for a universe of existing cases that may be historically related to the input case. After results of the queries are collected, execution proceeds to block 233 .
Block 233 , which represents the activity of comparison module 133 , entails measuring the similarity of the parties in the retrieved prior-case candidates to those extracted from the input case. In the exemplary embodiment, this similarity is measured or scored using the following objective function:
f=αS+βV+γC (2)
where the respective weighting coefficients, α, β and γ, are empirically selected as 0.25, 0.5, and 0.25, and components S, V, and C are defined as follows.
S, which estimates the similarity between the corresponding parties as a function of the total possible, is defined as
S = 1 K ∑ k = 1 K s ^ k ( 3 )
where k (lowercase) denotes a set of parties delimited by “versus” or one of its common abbreviations “v.” and “vs.”; K (uppercase) denotes the total number of such sets (for example if there is one “v.” then K=2, and if there are two, then K=3); and ŝ k denotes the score for the maximally matching party pair in the k-th set.
In measuring the similarity in the titles of an input case to the title of a prior-case candidate, the exemplary embodiment compares each party in the input case to each party in the prior-case candidate and determines a score for their similarity. The algorithm considers all possible correspondences and selects those resulting in maximum similarities, with the exception that parties from the same side of the “v.” in one case are not allowed to match parties from different sides of the “v.” in the second case, and vice versa when the maximum similarities are selected. Thus, for example, if the instant case has parties A, B, C, and D and the prior-case candidate has parties E, F, G, and H, then A is compared with E, F, G, and H to determine scores AE, AF, AG, and AH; B is compared with E, F, G, and H to determine scores BE, BF, BG, and BH; and so forth. If the maximal matching party pairs were found to be AE=0.9, BF=0.8, CG=0.95, DH=0.7, then S would be computed as S=(0.9+0.95)/2=0.925.
More precisely, the exemplary embodiment uses a specific type of matching or similarity scoring for each of the four types of party entities: person entities, place entities, company entities, and agency entities.
Person entities are scored as follows. If both entities are of the form <First, Middle Initial, Last> then all of these terms must match exactly. If the first name or the middle initial is missing, the last names must match person entities match if their last names match exactly and there is consistency between any remaining information. For example, David Smith matches Smith and would score 1.0, but David Smith would not match Mary Smith and score 0.0. Michelle Smith matches Michele Smith, but the match score of 1.0 is discounted by a predetermined amount, such as 15 or 20%, for each letter difference in the spellings, effectively implementing a fuzzy-match criteria that estimates the degree of match according to the number of letters (edits) needed to convert one word to another as a function of word length. The exemplary embodiment use the Levenshtein string-matching algorithm for this purpose. (See, for example, V. I. Levenshtein, Binary Codes Capable of Correcting Deletion, Insertions, and Reversal, Cybernetics and Control Theory, Vol. 10, pp. 707-710 (1966), which is incorporated herein by reference.) Michelle Smith also matches Michelle Smith-Johnson to accommodate last-name changes due to marriage.
Place entities match as long as there is no inconsistency. For example, Rochester matches City of Rochester and would score 1.0, but Town of Rochester does not match City of Rochester and would score 0.0. This has the effect of enforcing strict word agreement between nouns representing cities, counties, and states as well as place types, such as city.
The comparison and scoring for the third and fourth types of party entities, namely company and agency, is slightly different than person and place entities because company and agency entities may contain other party entities. If the company and agency parties do not include person or place entities or if these entities are consistent or not in conflict with each other, then the similarity between the two company (agency) entities or objects is estimated according to the edit distance between them. That is, the similarity is computed by
s = 1 - d l , ( 4 )
where d denotes the edit distance between two parties measured in words, and 1 denotes the maximum number of words of either party. If there is inconsistency in the person or place entities, the matched is scored as 0.0.
V estimates the title coverage as given by the party correspondences (that is, does the set of party correspondences cover both sides of the “v.” in both cases, and if yes, what is the degree of coverage.) Mathematically, V is defined as
V = ∏ k = 1 K s ^ k ( 5 )
C estimates the similarity between the titles of the instant case and a prior-case candidate using the following cosine criterion.
C = cos θ ij = v i ′ · v j ′ v i × v j , ( 6 )
where vector V i and V j denote respective title vectors for the input case and the j-th prior-case candidate case. Each vector includes a number of components, with each component being a weight associated with a term in the respective title and defined as
v= 1/log( df+ 1) (7)
This component limits the effect of parse errors caused by unknown words and/or erroneous punctuation. The prime notation reflects that the dot product is based on the terms that the input vector and the prior-case candidate vector have in common.
The exemplary embodiments sets all similarities less than an empirically estimated threshold, such as 0.33, to zero. This is desirable if the overall matching score is to be used as a measure of title similarities. This definition does not favor titles with a large number of parties over those with smaller number of parties.
The party-matching module estimates the similarity between retrieved cases and the instant case, which are compared to a threshold to produce a ranked list of prior candidates. The similarity estimates are based on similarities between the corresponding case titles. (Some embodiments make prior-case recommendations or linkages based on this list, by for example, recommending or linking to an arbitrary number of the top-ranked prior-case candidates.) Exemplary execution then proceeds to block 234 .
Block 234 , which represents the activity of support vector machine 134 , uses kernel-learning techniques to extract and process additional clues regarding a possible prior-case relationship between the input case and the prior-case candidates. Specifically, block 234 includes process blocks 234 . 1 and 234 . 1 .
Block 234 . 1 entails defining a number of feature vectors, with each feature vector based on both the input case and its relation to one of the prior-case candidates. The exemplary embodiment defines each feature vectors using the following eight features: (1) Title Similarity, (2) History Language, (3) Docket Match, (4) Check Appeal, (5) Prior Probability, (6) Cited Case, (7) Title Weight, and (8) AP1 Search.
(1) Title Similarity is a measure of the similarity between the title of the input case and that of a respective one of the prior candidate. In the exemplary embodiment, this is the score assigned to the prior-case candidate by comparison module 133 in block 233 .
(2) History Language is a binary feature indicating whether or not the input case includes direct history language, that is, procedural, dispositional, or directional language that indicates or suggests existence of a prior case. (See, for example, Peter Jackson et al., Information Extraction from Case Law and Retrieval of Prior Cases by Partial Parsing and Query Generation, Proceedings of the 1998 ACM CIKM: 7 th International Conference on Information and Knowledge Management, pp. 60-67 (1998), which is incorporated herein by reference.) In some embodiments, the value for the binary History Language feature is determined within extraction module 131 . In general, because of the difficulties of reliable determining the existence of direct history language, this feature in not dispositive of prior-case existence. Indeed, experiments suggests recall in the low 80-85% range and precision in the 50-60% range for extraction of history language.
(3) Docket Match is a binary feature indicating whether or not the instant-prior case pair has been assigned the same docket. Although one might expect courts to use the same dockets throughout an appeal process for a given case, statistics suggest that only 19.5% of prior-case pairs (pairs of cases that have a prior-case relationship with each other) in the database are assigned the same dockets. Moreover, even when the same court is hearing both the instant and the prior cases, the statistics suggest that the same docket number is used only 57% of the time. Indeed, only 29% of the 1.3 million cases within an appellate chain in the database are considered by the same court.
(4) Check Appeal is an estimate of the probability of the prior court for the respective candidate case given the instant court. In one sense, this feature effectively models the appellate chain as a Markov chain, with the courts being the different states and the Check Appeal estimates representing the conditional transitional probabilities from state to state. For some courts, statistics suggest that 90% or more of their prior to cases originate from a particular court, and the remaining 10% originate from a limited set of other courts. The exemplary embodiment computes this conditional probability according to
P ( prior court is pc | instant court is ic ) = ( pc ic ) ( 1 - 1 ic + 0.1 ) ( 8 )
where pc denotes the court of a prior candidate; is denotes the instant or input court (that is, the court hearing the input case); ∥ic∥ denote the number of cases in the instant court that have priors; and ∥pc∥ denote the number of cases in the instant court with priors coming from the prior court pc. The second term is a scaling factor that reflects a level of confidence in the estimated probability, particularly when the estimates are based on small sample sets.
(5) Prior Probability estimates the probability that the instant case has a prior case. From the outset, this can be viewed as the ratio of cases with priors to the total number of cases reported in the database. However, such a ratio can be corrected further by noticing that the probability of having a prior is a function of the instant court. Intuitively, if the instant case is in a court of last resort (such as, a state supreme court or US Supreme Court), then it is highly probable that it has a prior case. Statistics suggest that such probability has a jurisdictional dependence. For example, only 1.1% of cases considered by the Supreme Court of New Hampshire have prior cases in our database, while 94.3% of the cases considered by the Florida Supreme Court have prior cases in our database. This might be partially due to the fact that we do not keep track of all cases in all state jurisdictions. The exemplary embodiment estimates the prior probabilities using
P ( instant case has prior | instant court ) = ( c C ) ( 1 - 1 C + 0.1 ) ( 9 )
where C (uppercase) denotes the number of cases heard in the instant court, and c (lowercase) denotes the number of cases within C that have prior cases. Again, the second factor is a scaling factor adjustment for confidence.
(6) Cited Case is a binary feature indicating whether or not the prior case candidate is cited in the instant case.
(7) Title Weight estimates the discriminatory power of terms in the input case title. This feature is used to discriminate between a complete title match on more common term, such as “Smith,” and a complete title match on a less frequent term, such as “Alex J. Tyrrell.” The exemplary embodiment computes Title Weight using equation (1), which for convenience is repeated below:
w = 1 N ∑ i = 1 N 1 log ( d f i + 1 ) ( 10 )
where N is the number of terms in a party entity, and df i is the number of case titles of a training collection that include the i-th term. Some embodiments account for this discriminatory power in the title similarity score computed in block 233 .
(8) AP1 Search is a binary feature that indicates whether or not a prior-case candidate was retrieved through a query generated from the appeal (AP1) line in the instant case. The AP1 line is a line in the text of the instant case containing information about any existing prior case. A sample AP1 line is “AP1 @@, (Colbert Circuit Court, CV-96-104; Court of Civil Appeals, 2960768) $$.” However, the majority of cases (about 90%) do not include such a line.
Although the exemplary embodiment uses these eight features, other embodiments uses greater or lesser numbers of features. For example, one such embodiment uses a subset of four of the eight exemplary features, such as title similarity, title weight, history language, and check appeal. Another embodiment uses a subset of these four exemplary features, such as title similarity, and history language. Thus, the present invention is not limited to any particular set of features or numbers of features.
After defining the feature vectors in block 234 . 1 , execution continues with support vector processing in block 234 . 2 , which uses a support vector machine (SVM) 234 to score prior-case candidates according to their likelihood of being true prior cases. (More generally, support vector machines are used to discriminate between the positive and negative examples of a given category or class.) The exemplary embodiment implements the SVM using commercially available support-vector-learning software, such as SVM Light from Thorstein Joachims of Cornell University, Ithaca, N.Y. However, the invention is not limited to any particular kernel-learning or support-vector-learning methodology or software.
To train the SVM, the exemplary embodiment randomly selects 2100 cases from a main case database (not shown) and processes them using the pre-SVM portions of prior-case-retrieval processor 130 to accumulate up to 100 prior-case candidates per any given case. Each prior-case candidate was represented in terms of the exemplary eight-dimensional feature vector, yielding 113,000 training vectors. The SVM was trained using a linear kernel, with positive examples having five times more weight than negative examples. The training yields a hyperplane in the eight-dimensional feature space that separates more likely prior-case candidates from less likely prior-case candidates. Once trained, the feature vectors are fed into the SVM which scores them based on their “position” relative to the hyperplane, resulting in a ranked list of prior-case candidates. Execution continues at block 235 .
Block 235 , which represents the activity of decision-making module 135 , entails suggesting or recommending one or more of the prior-case candidates, based on respective SVM scores, as probable prior cases of the instant case. In the exemplary embodiment, this entails applying two thresholds Γ 1 and Γ 2 from decision-criteria module 136 . Γ 1 is an absolute threshold on the SVM score, which limits the number of instant cases that the system suggests priors for, and Γ 2 is a relative threshold based on the highest scoring prior-case candidate, which limits the number of suggestions made per input case. The exemplary embodiments sets Γ 1 and Γ 2 respectively to 4.8 and 0.7 based empirically on the scores of a tuning set of 800 unseen instant cases.
Block 240 shows that prior-case candidates with SVM scores that satisfy both threshold criteria are ultimately forwarded in association with the input case to preliminary-decision database 140 . Database 140 sorts the recommendation based on jurisdiction, or other relevant criteria and stores them in, for example, a single first-in-first-out (FIFO) queue or in multiple FIFO queues. The exemplary method then continues at block 235 .
Block 250 , which represents the activity of work center 150 , entails accepting or rejecting one or more of the prior-case candidates from database 140 . Specifically, one or more of the prior-case candidates are communicated by request or automatically to work center 150 , specifically workstations 152 , 154 , and 156 . Each of the workstations displays, automatically or in response to user activation, one or more graphical-user interfaces, such as graphical-user interface 152 . 1 .
FIG. 3 shows an exemplary form of graphical-user interface 152 . 1 . Interface 152 . 1 , which may be deployed as webpage or other functionally similar device, includes concurrently displayed windows or regions 310 , 320 , 330 , and 340 . Region 310 includes a list of case or selectable document identifiers, such as an identifier 211 , with each identifier corresponding to one prior-case candidate that satisfies the decision-making criteria of module 136 . Selection of an identifier changes in appearance and causes display of associated information in region 320 .
Specifically, region 320 includes regions 321 and 322 . Region 321 displays text of the selected case, with any history language visibly highlighted relative to other portions of the text. Region 322 displays various scores and other information generated and/or used by prior-case-retrieval processor 130 in making its decision to recommend the selected case as a prior-case candidate.
Region 330 displays text of the input case associated with prior-case candidates, with any history language visibly highlighted relative to other portions of the text. The exemplary embodiment highlights this language using underlining and/or reverse-video display. Region 330 also includes scrolling features (not shown.)
Region 340 includes selectable command inputs 331 and 332 . Selection of input 331 accepts the selected case for linkage with the input case, and selection of input 332 rejects the selected case. Acceptance in some embodiments invokes an additional screen or dialog window, allowing a user to enter text directly into a history field associated with the input case.
FIG. 2 shows that after processing of the recommendations, execution of the exemplary method continues at block 260 with update of the recommendation decision criteria. In the exemplary embodiment, this entails counting the numbers of accepted and rejected recommendations, and adjusting one or more decision thresholds appropriately. For example, if 80% of the recommendations for a given jurisdiction are rejected during one day, week, month, quarter or year, the exemplary embodiment may increase a generic thresholds or thresholds associated with that jurisdiction to reduce the number of recommendations. Conversely, if 80% are accepted, the threshold may be lowered to ensure that a sufficient number of recommendations are being considered. Some embodiments incorporate accepted cases into the appeal probabilities for various courts on an daily, weekly, monthly, quarterly, or other temporal or event-driven basis.
OTHER APPLICATIONS
Teachings of the present invention are expected to have other applications beyond the legal one presented here. One of these is to determine or recommend linkages between documents, such as scientific papers, that directly reference each other through citations or that are substantially related by overlapping sets of citations. Another application is as a highly refined categorical search engine. In this context, one embodiment couples support-vector machine (with appropriate interface functions) on the output of any available search engine to filter its results. Variants of this embodiment train the support-vector machine on case law concerning one or more legal topics.
CONCLUSION
In furtherance of the art, the present inventors have presented systems, methods, and software that generally facilitate identification of one or more documents that are related to a given document, and particularly facilitate identification of prior cases for a given case. One specific embodiment extracts case information, such as party names, courts, dates, docket numbers, and history language, from an input case, retrieves and ranks a set of candidate cases based on the extracted case information, compares one or more of the ranked cases to the input case using a support vector machine, ultimately linking or suggesting linking of the input case to one or more of the ranked cases.
The embodiments described above are intended only to illustrate and teach one or more ways of making and using the present invention, not to restrict its breadth or scope. The actual scope of the invention, which embraces all ways of practicing or implementing the teachings of the invention, is defined only by one or more issued patent claims and their equivalents. | 4y
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a Divisional of U.S. application Ser. No. 09/617,791, filed Jul. 18, 2000, now U.S. Pat. No. 6,618,223, Sep. 9, 2003, which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
The present invention relates to magnetic data recording and more specifically to a method for making a high data rate, high data density inductive writer.
BACKGROUND OF TH INVENTION
Magnetic disk drives are used to store and retrieve data for digital electronic apparatus such as computers. In FIGS. 1A and 1B , a magnetic disk data storage system 10 of the prior art includes a sealed enclosure 12 , a disk drive motor 14 , one or more magnetic disks 16 , supported for rotation by a drive spindle 18 of motor 14 , and an actuator 20 including at least one arm 22 , the actuator being attached to a pivot bearing 24 . Suspensions 26 are coupled to the ends of the arms 22 , and each suspension supports at its distal end a read/write head or transducer 28 . The head (which will be described in greater detail with reference to FIGS. 2A and 2B ) typically includes an inductive write element with a sensor read element. As the motor 14 rotates the magnetic disk 16 , as indicated by the arrow R, an air bearing is formed under the transducer 28 causing it to lift slightly off of the surface of the magnetic disk 16 , or, as its is termed in the art, to “fly” above the magnetic disk 16 . Alternatively, some transducers, known as contact heads, ride on the disk surface. Various magnetic “tracks” of information can be written to and/or read from the magnetic disk 16 as the actuator 20 causes the transducer 28 to pivot in a short arc across a surface of the disk 16 . The pivotal position of the actuator 20 is controlled by a voice coil 30 which passes between a set of magnets (not shown) to be driven by magnetic forces caused by current flowing through the coil 30 .
FIG. 2A shows the distal end of the head 28 , greatly enlarged so that a write element 32 incorporated into the head can be seen. The write element 32 includes a magnetic yoke 34 having an electrically conductive coil 36 passing therethrough.
The write element 32 can be better understood with reference to FIG. 2B , which shows the write element 32 and an integral read element 38 in cross section. The head 28 includes a substrate 40 above which the read element 38 and the write element 32 are disposed. A common edge of the read and write elements 38 , 32 , defines an air bearing surface ABS, in a plane 42 , which can be aligned to face the surface of the magnetic disk 16 (see FIGS. 1A and 1B ). The read element 38 includes a first shield 44 , a second shield 46 , and a read sensor 48 that is located within a dielectric medium 50 between the first shield 44 and the second shield 46 . The most common type of read sensor 48 used in the read/write head 28 is the magnetoresistive (AMR or GMR) sensor, which is used to detect magnetic field signal changes in a magnetic medium by means of changes in the resistance of the read sensor imparted from the changing magnitude and direction of the magnetic field being sensed.
The write element 32 can be better understood with reference to FIG. 2B , which shows the write element 32 and an integral read element 38 in cross section. The head 28 includes a substrate 40 above which the read element 38 and the write element 32 are disposed. A common edge of the read and write elements 38 , 32 , defines an air bearing surface ABS, in a plane 42 , which can be aligned to face the surface of the magnetic disk 16 (see FIGS. 1A and 1B ). The read element 38 includes a first shield 44 , a second shield 46 , and a read sensor 48 that is located within a dielectric medium 50 between the first shield 44 and the second shield 46 . The most common type of read sensor 48 used in the read/write head 28 is the magnetoresistive (AMR or GMR) sensor, which is used to detect magnetic field signal changes in a magnetic medium by means of changes in the resistance of the read sensor imparted from the changing magnitude and direction of the magnetic field being sensed.
The write element 32 is typically an inductive write element that includes the second shield 46 (which functions as a first pole for the write element) and a second pole 52 disposed above the first pole 46 . Since the present invention focuses on the write element 32 , the second shield/first pole 46 will hereafter be referred to as the “first pole”. The first pole 46 and the second pole 52 contact one another at a backgap portion 54 , with these three elements collectively forming the yoke 34 . The combination of a first pole tip portion and a second pole tip portion near the ABS are sometimes referred to as the ABS end 56 of the write element 32 . Some write elements have included a pedestal 55 which can be used to help define track width and throat height. A write gap 58 is formed between the first and second poles 46 and 52 in the area opposite the back gap portion 54 . The write gap 58 is filled with a non-magnetic, electrically insulating material that forms a write gap material layer 60 . This non-magnetic material can be either integral with or separate from a first insulation layer 62 that lies upon the first pole 46 and extends from the ABS end 56 to the backgap portion 54 . The conductive coil 36 , shown in cross section, passes through the yoke 34 , sitting upon the write gap material 60 . A second insulation layer 64 covers the coil and electrically insulates it from the second pole 52 .
An inductive write head such as that shown in FIGS. 2A and 2B operates by passing a writing current through the conductive coil 36 . Because of the magnetic properties of the yoke 28 , a magnetic flux is induced in the first and second poles 46 and 52 by write currents passed through the coil 36 . The write gap 58 allows the magnetic flux to fringe out from the yoke 34 (thus forming a fringing gap field) and to cross the magnetic recording medium that is placed near the ABS.
With reference to FIG. 2C , a critical parameter of a magnetic write element is the trackwidth of the write element, which defines track density. For example, a narrower trackwidth can result in a higher magnetic recording density. The trackwidth is defined by the geometries in the ABS end 56 of the yoke. For example, the track width can be defined by the width W 3 of the pedestal 55 or by the width W 1 of the second pole 52 , depending upon which is smaller. The widths W 3 and W 1 can be the same, such as when the second pole 52 is used to trim the pedestal 55 . Alternatively, in designs that have no pedestal at all it would be possible to define the trackwidth by the width W 2 of the first pole.
With reference to FIG. 2B , the fringing gap field of the write element can be further affected by the positioning of the zero throat level ZT. ZT is defined as the distance from the ABS to the first divergence between the first and second pole, and it can be defined by either the first or second pole 46 , 52 depending upon which has the shorter pole tip portion. Pedestal defined zero throat is defined by the back edge of the pedestal and is accomplished by moving the second insulation layer 64 back away from the ABS. Alternatively, zero throat can be defined by the geometry of the second pole 52 , by allowing the second insulation layer 64 to extend over the top of the pedestal. In order to prevent flux leakage from the second pole 52 into the back portions of the first pole 46 , it is desirable to provide a zero throat level that is well defined with respect to the plane of the ABS. Furthermore, a pedestal defined zero throat is beneficially defined along a well defined plane that is parallel with the plane 42 of the ABS, whereas a zero throat defined by the second pole occurs along the sloped edge of the second insulation layer 64 . As will be appreciated upon a reading of the description of the invention, the present invention can be used with either pedestal defined zero throat or a second pole defined zero throat. Thus, accurate definition of the trackwidth, and zero throat is critical during the fabrication of the write element.
The performance of the write element is further dependent upon the properties of the magnetic materials used in fabricating the poles of the write element. In order to achieve greater overwrite performance, magnetic materials having a high saturation magnetic flux density (high B sat ) are preferred. A common material employed in forming the poles is high Fe content (55% Fe) NiFe alloy having a B sat of about 16 kG. However, high Fe content NiFe alloy has a high magnetostriction constant λs (on the order of 10 −5 ) which causes undesirable domain formation in the poles. It is known that the domain wall motion in the writer is directly related to the increase in popcorn noise in the read element, especially when the motion occurs in the first pole, which also serves as a shield for the read element. A reduction in popcorn noise in the read element can be achieved through the use of soft magnetic materials, (i.e. materials having a low magnetostriction constant) in the fabrication of the first pole 46 . However, such materials generally have limited B sat .
Therefore, there remains a need for a write element having the ability to concentrate a high degree of magnetic flux in the ABS end of the write element, while minimizing or eliminating popcorn noise caused by magnetostrictive properties of the write element. Such a write element would preferably provide a narrow and accurately controlled trackwidth as well as providing high overwrite, low non-linear transition shift, a high areal density and high data rate.
SUMMARY OF THE INVENTION
The present invention provides an inductive write element having improved magnetic performance characteristics, including high overwrite, low non-linear transition shift, high areal density and high data rate. The write element includes first and second poles, each constructed of a magnetic material and joined to one another to form a magnetic yoke. The poles are joined to one another at one end to form a back gap region, the other end having a write gap defined between the poles. An electrically conductive coil passes through the yoke between the first and second pole, and insulating material electrically isolates the electrically conductive coil from the magnetic yoke. The second pole includes a layer of a laminated high magnetic moment material, sputter deposited as a sheet film across the inner surface of the pole adjacent to the insulation material and write gap.
The present invention provides an inductive write element having improved magnetic performance characteristics, including high overwrite, low non-linear transition shift, high areal density and high data rate. The write element includes first and second poles, each constructed of a magnetic material and joined to one another to form a magnetic yoke. The poles are joined to one another at one end to form a back gap region, the other end having a write gap defined between the poles. An electrically conductive coil passes through the yoke between the first and second poles, and insulating material electrically isolates the electrically conductive coil from the magnetic yoke. The second pole includes a layer of a laminated high magnetic moment material, sputter deposited as a sheet film across the inner surface of the pole adjacent to the insulation material and write gap.
Forming only the inner portion of the second pole of high magnetic moment material and the remainder of a material such as NiFe advantageously allows the write element to be formed using currently available manufacturing techniques. Currently available high magnetic moment materials cannot be deposited by electroplating and are generally sputter deposited. By first sputter depositing the high magnetic moment material and then plating the remainder of the second pole with the lower magnetic moment material, the plated portion of the pole can be used as a mask to etch the sputtered material to provide the desired second pole configuration.
In an embodiment of the invention, the first pole can include a pedestal formed of the laminated high magnetic moment material, sputter deposited as a sheet film. Such a pedestal would be formed in the region of the write gap and would beneficially concentrate magnetic flux in the desired portion of the write gap. As an aspect of the invention, the high magnetic moment material used in the first and second poles can be FeXN, where X is a material selected from the group consisting of Rh, Ta, Al, Ti and Zr. The high magnetic moment material can additionally be laminated with layers of a dielectric film which more preferably can be a cobalt based amorphous ferro-magnetic material, and most preferably is CO 90 Zr 9 Cr. CO 90 Zr 9 Cr has been found to improve anisotropic properties. Such laminated materials can preferably include layers of high magnetic moment materials on the order of 500 Angstroms thick, interspersed with lamination layers of cobalt based amorphous ferro-magnetic material or alternatively of a non-magnetic material in layers that are roughly 50 Angstroms thick.
These and other advantages of the present invention will become apparent to those skilled in the art upon a reading of the following descriptions of the invention and a study of the several figures of the drawings.
BRIEF DESCRIPTION OF THE FIGURES
The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, with like reference numerals designating like elements.
FIG. 1A is a partial cross-sectional front elevation view of a magnetic data storage system of the background art;
FIG. 1B is a top plan view taken along line 1 B— 1 B of FIG. 1A ;
FIG. 2A is a is a plan view of a portion of a read/write head, shown greatly enlarged;
FIG. 2B is a view taken from line 2 B— 2 B of FIG. 2A , shown enlarged;
FIG. 2C is a view taken from line 2 C— 2 C of FIG. 2B ;
FIG. 3 is a view similar to FIG. 2B showing a read/write head of the present invention in cross section;
FIG. 4 is a flowchart illustrating a process for constructing a write element embodying the present invention; and
FIG. 5 is a view taken from line 5 — 5 of FIG. 3 .
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
With reference to FIG. 3 the present invention is embodied in a merged read/write head 66 including a read element 68 and an integral write element 70 , both of which are built upon a substrate 72 . The read element 68 having been described with reference to the background of the invention, the present description will focus on the write element 70 , which embodies the subject matter of the present invention.
The write element 70 includes first and second poles 74 , 76 , which together join to form a magnetic yoke 78 . The poles 74 , 76 join at one end to form a back-gap 80 , and are separated from one another everywhere else. Opposite the back-gap, each pole 74 , 76 terminates in a pole tip 82 , 84 . Opposite the back gap 80 , the poles 74 , 76 are separated by a write gap 88 . A layer of dielectric write gap material 89 fills the write gap and extends beyond the write gap into the interior of the yoke 78 . An electrically conductive coil 90 passes through the yoke 78 sitting atop the write gap material layer 89 .
With continued reference to FIG. 3 , the first pole 74 is constructed of a magnetic material having soft magnetic properties (i.e. low magnetostriction), preferably permalloy. Such soft magnetic properties are necessary to avoid domain boundary movement and associated popcorn noise in the read element 68 . The first pole 74 includes a pedestal 92 , disposed opposite the back-gap 80 . The pedestal is constructed of a high magnetic moment material and functions to concentrate magnetic flux. While plated high magnetic moment materials do not generally exhibit soft magnetic properties, the pedestal is located far enough away from the read element 68 and is sufficiently small in size as compared with the rest of the first pole 74 so as to not generate undesirable popcorn noise. To further improve performance, the pedestal is preferably constructed of FeXN nanocrystalline films with lamination layers of CoZrCr, which has been found to exhibit excellent magnetic properties including high magnetic moment and relatively low magnetostriction. The FeXN and the lamination layers are preferably sputter deposited onto a flat wafer that has been planarized using by chemical mechanical polishing (CMP).
With continued reference to FIG. 3 , a first insulation layer 94 covers the first pole, having a smooth flat upper surface that is flush with the smooth flat upper surface of the pedestal 92 . While this first insulation layer can be of many suitable materials having a high electrical resistance it is preferably constructed of Al 2 O 3 .
With reference still to FIG. 3 , the write gap material layer 89 sits atop the smooth coplanar surfaces of the first insulation layer 94 and the pedestal 92 . The write gap material layer is preferably constructed of Al 2 O 3 or alternatively of SiO 2 . The coil 90 sits atop the write gap material layer 89 and is also covered by a second insulation layer 96 , which insulates the coil 90 from the second pole 76 as well as insulating the winds of the coil 90 from one another. The second insulation layer has smoothly rounded edges formed by a curing process that will be described in greater detail below.
With continued reference to FIG. 3 , the second pole 76 includes a high magnetic moment layer 98 . The remainder of the second pole 76 consists of a secondary layer 100 , constructed of a magnetic material such as plated Ni—Fe alloy, which can be readily electroplated and which exhibits good corrosion resistance. The high magnetic moment material layer 98 , which is preferably constructed of laminated FeXN nanocrystalline films with lamination layers of CO 90 Zr 9 Cr, improves performance of the head by facilitating magnetic flux flow through the second pole 76 , thereby resulting in a stronger fringing field at the write gap. The secondary layer 100 , which preferably makes up the bulk of the second pole 76 , provides a mask for etching the high magnetic moment material layer 98 as will be described in greater detail below. In order to minimize apex reflection during the photolithograpy process used to define the top pole, it is desirable that the edge of the coil insulation layer 96 be placed further from the ABS than the pedestal edge, in which case the zero throat is defined by the pedestal. Apex reflection is a major source of trackwidth variation during the fabrication of the top pole. By moving the coil insulation layer 96 away from the ABS and plating the second pole 76 onto a flat surface in the area near the ABS, the trackwidth can be more easily controlled. The high magnetic moment layer 98 is preferably on the order of 1 to a few times the thickness of the write gap 88 . In one embodiment the high magnetic moment layer 98 is roughly 0.5 um thick while the remainder of the second pole 76 is roughly 2 um thick and the pedestal is roughly 1 um thick. The throat height is preferably 3–10 times the thickness of the write gap 88 .
In an alternate embodiment of the invention, not shown, the second pole includes a layer of laminated high magnetic moment material as discussed above, but the first pole includes no pedestal. In another embodiment, the first pole includes a pedestal constructed of laminated high magnetic moment material, but the second pole does not include a laminated high magnetic moment layer. Such a construction could be useful where magnetic flux saturation is a problem. For example, if saturation were experienced in the pedestal of the first pole, then removing the high magnetic moment material from the second pole would decrease flux flow through the second pole, thereby preventing saturation at the pedestal. Similarly, when saturation is experienced in the second pole, the design having a high magnetic moment layer in the second pole and no pedestal on the first pole would promote flux flow through the second pole while limiting flux flow through the first pole, thereby preventing saturation in the second pole.
In still another embodiment of the invention, the high magnetic moment layer 98 of the second pole 76 can be constructed of laminated FeXN nanocrystalline films with lamination layers of cobalt based amorphous ferro-magnetic alloy or alternatively of a non-magnetic dielectric material, while the pedestal is constructed of some other material such as a Ni—Fe alloy that can be electro-plated. Alternatively, the pedestal can be constructed of FeXN nanocrystalline films with lamination layers of a cobalt based amorphous ferromagnetic alloy or of a non-magnetic dielectric material, while the high magnetic moment layer of the second pole is some other plated high magnetic moment material such as NiFe55.
With reference now to FIG. 4 , a process 400 is provided for constructing a write element of the present invention. The process begins with a step 402 of constructing the first pole 74 . The first pole is preferably constructed by patterning and electroplating permalloy according to lithographic techniques familiar to those skilled in the art, and then is planarized by a chemical mechanical polishing process. Then, in a step 404 a layer of high magnetic moment (high B sat ) material is sputter deposited onto the first pole. This sputtering process results in a layer of high B sat material that completely covers the first pole as well as surrounding structure. Thereafter, in a step 406 the pedestal is patterned. A layer of photoresist is deposited so as to form a mask covering the area where the pedestal is to be formed. Then, in step 408 , ion milling is performed to the sputtered high B sat material not covered by the photoresist mask, thus forming the pedestal 92 . The ion milling step leaves a tail of sputtered material tapering from the edge of the pedestal 92 .
With further reference to FIG. 4 , in a step 410 a first insulation layer 94 is deposited onto the first pole. This first insulation layer 94 is preferably constructed of Al 2 O 3 and is deposited sufficiently thick to at least reach the thickness of the pedestal 92 and is preferably slightly thicker than the pedestal 92 . Thereafter, in a step 412 a chemical mechanical polishing step is performed to planarize the first insulation layer 94 , generating a flat planar surface across the first insulation layer 94 and the top of the pedestal 92 . In a step 414 the write gap material layer 89 is deposited onto the smooth planar surface of the first insulation layer 94 and the pedestal 92 . The write gap material layer can be constructed of many suitable dielectric substances, but is preferably constructed of Al 2 O 3 or alternatively of SiO 2 .
In a step 416 , the electrically conductive coil 90 is formed. The coil is preferably constructed of copper and is formed by methods that are familiar to those skilled in the art. These methods involve first depositing a seed layer of copper or some other suitable conductive material. The coil is then patterned and electroplated, and the seed layer removed by an etching process. With the coil thus formed, in a step 418 the second insulation layer 96 is formed. The second insulation layer is preferably constructed of a photoresist, which is spun onto the write gap material 89 and the coil 90 . The photoresist is patterned and exposed so that selective portions of the photoresist can be removed to provide vias for the back gap and the coil leads. Then the photorsist photoresist is cured by exposure to high temperatures, hardening the photoresist and providing it with smoothly rounded edges. In order to improve properties of the sputtered layer, a thin layer of dielectric material can be added to the top of the photoresist material.
With reference still to FIG. 4 , the formation of the second pole will now be described. In a step 420 , a thin layer of high B sat material is sputter deposited onto the structure. As will be appreciated by those skilled in the art, sputter deposition will cover the entire exposed structure, including the second insulation layer 96 and the write gap material layer 89 . The high B sat material is preferably constructed of FeRhN nanocrystalline films with lamination layers of CoZrCr, however other high B sat at materials can also be used. Then, in a step 422 the remainder of the second pole 76 is deposited. This step involves forming a mask and then electroplating the second pole. Using such standard electroplating and photolithographic processes, the electroplated portion of the second pole 76 can be formed with the desired shape. The electroplated portion of the first pole is preferably constructed of a NiFe alloy suitable for electroplating. With the electroplated portion of the second pole acting as a mask, in a step 424 an etching process is conducted to remove the high B sat material that is not covered by the plated portion of the second pole 76 . This effectively results in a desired second pole 76 being primarily constructed of a magnetic material such as permalloy, and having a high B sat inner layer. The resulting pole structure includes a tail (not shown) of high B sat material that extends outward slightly from the edge of the pole 76 , beyond the edge of the plated portion. Also, as previously discussed the ion milling step leaves some of the sputtered material re-deposited on the sidewalls of the second pole 76 .
With continued reference to FIG. 4 , in a step 426 , the pole tip of the second pole 76 is masked with photoresist. Then, in a step 428 the structure is again ion milled to remove material from the uncovered side portions of the tip of the second pole 76 . Thereafter, in a step 430 an etching process is performed to remove write gap material in the pole tip region at the sides of the second pole 76 . Then, with the write gap material locally removed, in a step 432 , yet another ion mill is performed to remove material from the corners of the pedestal 92 leaving notches 102 in the pedestal 92 , which can be more clearly seen with reference to FIG. 5 , which shows an ABS view of the resulting pole trimmed pedestal. The notches 102 in the pedestal prevent magnetic flux from flowing through the sides of the yoke, thereby preventing side writing.
As will be appreciated by those skilled in the art, the above process can be slightly modified to construct one of the earlier described alternate embodiments of the invention. For example, the write element 70 could be constructed without the pedestal by patterning the first insulation layer to terminate short of the ABS plane 86 and eliminating the pedestal deposition process. In such a case the write gap material layer would simply slope down along the edge of the first insulation layer, and would sit atop the first pole 74 in the region of the write gap. Alternatively, the write element 70 could be constructed with a pedestal 92 as described above, but with a second pole formed without a laminated high B sat layer. Furthermore, high B sat layer of the second pole can be constructed of FeRhN nanocrystalline films with lamination layers of CoZrCr while the pedestal is constructed of some other magnetic material. Similarly, the pedestal can be constructed of FeRhN nanocrystalline films with lamination layers of CoZrCr while the high B sat layer of the second pole is constructed of plated high B sat material such as NiFe55.
With reference now to FIG. 5 , in an alternate embodiment of the invention, the pedestal can be constructed very thin with a tapered edge. Making the pedestal thin advantageously simplifies the manufacturing process, and the tapered edge promotes flux flow into the pedestal, avoiding magnetic saturation in the pedestal. A method for constructing a write element having such pedestal is described in U.S. patent application Ser. No. 09/602,536, titled “INDUCTIVE WRITE HEAD INCORPORATING A THIN HIGH MOMENT PEDESTAL”, filed on 23 Jun. 2000, the entirety of which is incorporated herein by reference.
While the present invention has been particularly shown and described with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit, scope and teaching of the invention. Accordingly, the disclosed invention is to be considered merely as illustrative and limited in scope only as specified in the appended claims. | 4y
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BACKGROUND OF THE INVENTION
The invention concerns a disinfection system for disinfection of contact lenses and comprising a sealed disposable package containing a suitable amount of disinfection liquid to disinfect a set of contact lenses.
Users of contact lenses are aware that, at best, contact lenses are to be cleaned and disinfected daily to avoid trouble in use.
In practice, disinfection of contact lenses takes place in that a disinfection liquid from a container is poured into a specially designed lens case in which the cleaning process takes place. The lens case consists of a lens holder with a lens basket usually secured to the underside of the lens case lid as well as a container to receive disinfection/neutralization liquid onto which the lid may be screwed. When the contact lenses have been placed in the lens baskets, the lens case lid is screwed on the case, whereby the lens baskets with the contact lenses are immersed into the disinfection liquid in the container and are thereby cleaned.
Various types of liquids are used for cleaning contact lenses, depending on the cleaning system used by the user. One of the systems comprises the use of two liquids, the method comprising first immersing the lenses into hydrogen peroxide (H 2 O 2 ), which is a very strong disinfecting and cleaning liquid. After the disinfection, the lenses are immersed into a neutralization liquid, and then the contact lenses are ready for use. Sometimes the users of this system forget how far they have gone in the cleaning process, and since the neutralization liquid has the same color as the hydrogen peroxide solution, the user may be easily mistaken or his memory may be at fault, and consequently there have been several cases where the user, believing that the lenses had been neutralized, has then inserted them in the eye directly from the hydrogen peroxide solution, which is very painful.
To avoid such unfortunate actions, DK Patent No. 168 746 B1 proposes a cleaning system where the contact lenses are immersed into a two-compartment case with hydrogen peroxide, but where the case contains a third compartment which communicates with the two compartments and in which a soluble tablet containing a neutralization agent (catalase) is placed. The gradual dissolution of the tablet neutralizes the hydrogen peroxide solution so that the contact lenses will be disinfected and neutralized when the tablet has been dissolved completely after a certain period of time. However, a drawback of this disinfection system is that sometimes the user forgets to place the tablet in the case, so that the contact lenses are inserted without having been neutralized. Another risk is that the user inserts the contact lenses before the tablet has been dissolved completely and the hydrogen peroxide solution has not been neutralized completely.
Today, all-in-one liquids have been developed for simultaneous cleaning, disinfection and insertion of contact lenses, the idea being to take the lens directly from the disinfection liquid and to insert it in the eye. The disinfection agent in these liquids is relatively weak, since otherwise, it would disturb the environment of the eye and cause allergic reactions, because the lenses are not neutralized before being inserted. The all-in-one liquids are supplied in containers/bottles containing up to 360 ml, sufficient for two months, consumption, if the lenses are disinfected daily. In practice, 360 ml are frequently enough for more than two months, as the user saves or just uses the contact lenses at intervals. Health authorities have generally recommended smaller container sizes, corresponding to one month's consumption, it being desired to reduce the risk of bacterial growth in the container. Frequently, the container is stored in bathrooms with many bacteria and fungi, and the users frequently forget to screw the lid onto the container after use. An American study (Donzis) has shown bacterial growth in 11-66% of the containers.
The bacterial growth in the containers reduces the effect of the disinfection agent, weak as it is, so that its disinfecting effect is already reduced before it gets into contact with the contact lenses. The disinfection of the contact lenses will thus be incomplete, whereby the eye will be liable to infection.
The conclusion has been that the safest form of a package of all-in-one liquids is a disposable bottle, commonly called a unit dose, having a ml content corresponding precisely to that needed for one disinfection procedure. Such containers containing 15 ml are known, but are relatively expensive, and their bottle-like shape enables the user to use one half and to save the rest for the next day, which involves a risk of bacterial growth.
The previously mentioned lens case is used for disinfecting contact lenses with the all-in-one liquids and is thus a decisive element of the actual disinfection process. Because of the ability of bacteria to form their own protecting bio film, it is difficult to keep the lens case clean, and today it is therefore recommended to exchange the case as frequently as every month.
Exchange every three months is perhaps acceptable, if the user uses a strong disinfection agent, e.g., 3% hydrogen peroxide, which, however, requires neutralization of the disinfection agent and the lens before the lens is inserted.
Studies (Donzis) have shown that bacterial growth in lens cases differs significantly, depending on the disinfection agent used, within three weeks, use of a new case. If the hydrogen peroxide system is used, there is no bacterial growth within the first three weeks. If, however, all-in-one systems are used, growth occurs in 25% of the cases within the first 21 days. Thus, with bacterial growth in the case, the situation is quite different when using a so-called all-in-one system as the disinfection system.
The conclusion of the study is that if an all-in-one disinfection system is used, it is very important to maintain the effect of the disinfection agent during storage in the container by the user. Further, it is very important to use a sufficient and correct amount of a disinfection agent to disinfect the contact lenses. In addition, the lens case is to be exchanged, or sterilized in another manner to avoid reducing the effect of the disinfection agent in relation to the lens with the consequent risk of eye infection.
EP A1 381 616, EP A1 401 163 and FR A1 2 674 217 disclose disposable systems for cleaning contact lenses.
EP A1 381 616 concerns a disposable system for cleaning contact lenses, which comprises a first container to receive contact lenses and a second container containing a sterilization or disinfection agent. The first container has a means to pierce the lid on the second container when the second container is folded over the first container. The container with contact lenses contains a catalyst to degrade the sterilization agent.
EP A1 401 163 concerns a disposable system comprising two pairs of containers. The first pair contains a sterilization agent, and the second pair contains a neutralization agent. Contact lenses are cleaned by first placing the lenses in their respective containers with a sterilization agent and then transferring the lenses to the containers with a neutralization agent. The system may be provided with a lid, if the lenses are to be stored in the system for an extended period of time. Further, the system may be provided with a spoon-like means to handle the lenses.
FR A1 2 674 217 concerns a disposable container containing a cleaning liquid. In use, the lid of the container is removed by breaking a fragile area, and then the lenses are placed in the liquid. The lid may be applied to the container again.
Further, U.S. Pat. No. 5,375,698 discloses a contact lens container which is constructed with a base member having at least one compartment and provided with a laterally projected flange around the perimeter of the base member, a reusable adhesive is deposited on the projecting flange and a cover sheet member, extending at least across the full length and width of the compartment, is releaseably united to the base member at the flange by the adhesive and thus forming a fluid-tight seal.
These disposable systems have a number of drawbacks:
The lenses are to be handled either by the fingers or by a spoon-like means, which makes handling risky and lens damage likely.
The disposable systems are restricted either to all-in-one liquids or to two-liquid disinfection systems.
The disposable systems are made of a fragile material, which makes them mechanically unstable during transport (risk of leakage).
It is likely that the lenses are discarded together with the disposable system, as the lenses are difficult to see when they are present in the liquid.
SUMMARY OF THE INVENTION
The object of the invention is to provide a method of disinfecting contact lenses in a lens case filled with a disinfection liquid, where the contact lenses optionally are placed in a lens basket of a case suspended, e.g., from a case lid and down in the disinfection liquid when the lid is screwed onto the container, obviating the above-mentioned drawbacks, to ensure that the lens user uses the correct amount of disinfection liquid, and to ensure that the effect of the disinfection liquid is maintained until the moment when it contacts the contact lenses.
This object is achieved by a new distribution principle which radically departs from the traditional principles, where disinfection takes place in a disposable container, which is made of a fragile material, where handling of the contact lenses is very risky, e.g., by the fingers and where good control of the lenses is not possible.
The new distribution principle uses a new disinfection system to disinfect contact lenses, comprising a sealed disposable container containing a suitable amount of disinfection liquid to disinfect a set of contact lenses, said disposable container being formed with a wide mouth suitable for receiving holding means for contact lenses, characterized in that the disposable container is used as an insert in a container of a lens case. Thus, in addition to serving as a distribution unit in the form of a disposable package, the disposable container also serves as a disinfection container/vessel in connection with disinfection of contact lenses. With the new principle, both the disinfection liquid and the disposable container are exchanged after completed disinfection of the contact lenses, thereby eliminating the risk of bacterial growth in the container in which the disinfection takes place, and allowing the disinfection liquid to maintain its optimum effect until the moment when the seal on the disposable container is torn off and the lens baskets with the contact lenses are immersed into the disinfection liquid. Another advantage of the new disinfection principle is that when using disposable containers it ensures that the lens user uses the correct amount of disinfection liquid to disinfect the contact lenses.
At its opening, the disposable container is provided with an annular flange having an upper side to which a tear-off sheet seal is attached. This attachment method, providing a good contact face between the sheet and the flange, ensures that the disinfection liquid is protected effectively against bacterial attacks during storage until use. The flange moreover has several other functions, which will be mentioned below.
When the disposable container can also accommodate a means to receive the contact lenses or holding means for them, it is additionally ensured that the contact lenses may be effectively disinfected, and following disinfection of the contact lenses, it is moreover possible--in addition to exchange of disinfection liquid and the container in which the disinfection process takes place--to exchange the lens baskets more frequently than in the use of the traditional lens cases. The frequent exchange of the lens baskets means that they will not be infected by bacteria before they are exchanged. When the lens baskets are stored in the disposable containers containing disinfection liquid, the lens baskets may be considered to be sterile until the moment when the seal is torn off.
When the means to receive the contact lenses are formed by disposable lens baskets, the use of the disinfection system of the invention ensures the contact lenses may always be disinfected in an environment which is not infected by bacteria beforehand.
When the means to receive the contact lenses are arranged on a stem whose free end protrudes from the disinfection liquid level, it is ensured that contact between the user's fingers and the disinfection liquid in the disposable container is reduced to a minimum.
Also, the disposable container may be constructed such that it may be placed as a disposable insert in a container of a lens case, following which the seal across the opening is torn off prior to the mounting of the lid with the lenses in the lens baskets. The additional advantages of this are that the lens case container, which usually is a cylindrical transparent container of impact-proof plastics, and which takes more resources to manufacture than the disposable container, does not have to be exchanged with the common frequency, as it does not contact the disinfection liquid and is thus not subjected to bacterial attacks. Further, the lens case container is used for protecting the disposable container.
The disposable container of the invention containing means to receive the contact lenses or holding means (disposable lens basket) for this finds application as an insert in primitive lens cases which do not comprise a lens basket.
The protruding flange on the disposable container, provides a tight connection between the lid of the lens case and the disposable container, so that the container of the lens case is not contaminated by bacteria from the contact lenses, as the interior thereof does not get in contact with the disinfection liquid of the disposable container. The container of the lens case is thus used for securing and protecting the disposable container in the correct position below the lens baskets, as well as an additional protection against bacterial attacks.
The disinfection system of the invention is, moreover, extremely useful in connection with the use of the system, comprising a first cleaning in hydrogen peroxide (H 2 O 2 ) and a subsequent neutralization in a neutralization liquid, as the user is always certain of how far he has proceeded in the disinfection process, since the disposable containers are discarded as they are used. Thus, if the contact lenses are being disinfected in H 2 O 2 , the disposable container containing the neutralization liquid will be juxtaposed with an unbroken seal, thereby enabling it to be observed that the neutralization process has not been completed. A further safeguard against wrong use of disinfection liquid and neutralization liquid may comprise providing the disposable containers for the respective liquids with mutually different colors and/or shapes. This minimizes the risk of inserting non-neutralized contact lenses when using the disposable containers according to the invention.
The containers containing H 2 O 2 and neutralization liquid, respectively, may have different shapes and appearances, and the upper sides of the seals thereof may be provided with marks clearly indicating what the containers contain, thereby reducing the risk of mistakes.
Of course, the disposable containers are relatively small, as they are intended to be accommodated in the container part of the lens case. This means that they occupy very little space, and as a result the new distribution system, in addition to the advantages already mentioned, also have the same advantages with respect to space requirements as the known all-in-one disinfection liquids that are supplied in unit dose packages.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be explained more fully below with reference to the drawing, in which
FIG. 1 is a perspective view of an unopened disposable container with a lid,
FIG. 1A is lateral sectional view of FIG. 1, containing disposable lens baskets,
FIG. 2 is a perspective view of FIG. 1A, with partly a removed seal,
FIG. 3 is an exploded lateral view of FIG. 2 during insertion of contact lenses into the disposable lens baskets,
FIG. 3A shows the disposable container used as an insert in a simple lens case,
FIG. 4 is a lateral sectional view of the disposable container in an assembled state,
FIG. 5 shows the disposable container during removal of the tear-off sheet,
FIG. 6 is a lateral sectional view of the disposable container used as an insert in a normal lens case,
FIG. 7 is a perspective view of a lens case to receive disposable containers, and
FIG. 8 is a lateral sectional view of a lens case with an inserted disposable container during cleaning of contact lenses.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The disinfection system 1 of the invention is shown in FIG. 1 in an unopened state and comprises a disposable container 18 with a tear-off sheet seal 22 secured on an annular flange 26 (FIG. 2). The disposable container 18 is formed with a mouth wide enough to receive holding means 14, 19 for contact lenses 16 during the disinfection process.
As shown in FIG. 1A, a removable, tight-fitting lid 28 may be provided along the rim of the disposable container above the sheet seal 22. Further, the disposable container 18, in addition to the disinfection liquid 24, may also contain a set of lens baskets 19 secured to a stem 21, whose free end protrudes above the disinfection liquid level.
When the disinfection system 1 is to be used, the lid 28 is removed from the disposable container 18, and then the sheet seal 22 is torn off (FIG. 2). Then, the stem 21 is grasped by the finger tips and the lens baskets 19 are lifted out of the disposable container 18. The contact lenses 16 are then placed in the lens baskets 19, as appears from FIG. 3, which, in turn, are immersed into the disposable container 18 by again grasping the free end of the stem 21 by the finger tips. The lid 28 is applied over the opening of the disposable container (FIG. 4), and the disinfection process takes place.
The disposable container 18 may also be used as an insert in a simple lens case 3, without a lens basket, as appears from FIG. 3A. This embodiment of the disinfection system does not comprise the lid 28, the protruding flange 26 on the disposable container 18 being clamped between the rim of the lens case 5 and a sealing member 13, cooperating with it, in the form of an O-ring seal on the lid 7 of the lens case. Placing of the contact lenses 16 in the lens baskets 19 in connection with the disinfection process takes place as described before.
The embodiment of the disinfection system 1 shown in FIG. 5 for use together with traditional lens cases, with lens baskets 14 secured to a stem 15 whose free end is secured in the lens case lid 8, comprises a disposable container 18 with the tear-off sheet seal 22 described before. In use, as disclosed in FIG. 6, the disposable container 18 is placed in the container 4 of the lens case, before or after the sheet seal 22 is torn off. The contact lenses 16 are then placed in the lens baskets 14, and the lid 8 is applied to the container 4, whereby the lens baskets 14 containing the contact lenses 16 are immersed into the disinfection liquid 24. Application of the lid 8 causes the protruding annular flange 26 to be clamped between the rim of the container 4 and a sealing member 13, cooperating with it, in this case an O-ring on the lid 8.
A lens case 2 for use together with the disinfection system 1 of the invention is shown in a disassembled state in FIG. 7. The lens case 2 consists of two main parts, a container 4 whose external rim has bayonet threads 6 to enable the lid 8 to be screwed on.
As appears in FIG. 7, the inner side of the lid 8 has a plurality of gripping flaps 10 intended to engage the bayonet threads 10 on the container 4. An inner side 11 of the bottom of the lid is formed with an annular groove 12 in which a seal 13, in this case an O-ring, of a suitable material is embedded. The O-ring 13 is so positioned in the lid 8 that when the lid is screwed onto the container 4, the O-ring engages the upper edge of the container. As appears in FIG. 8, the underside of the lid 8 has two lens baskets 14 carried by a stem 15 which is inserted into the central hole 9 of the lid, said baskets being intended to receive a set of contact lenses 16. When the lid 8 is screwed firmly onto the container 4, the lens baskets 14 extend down into the interior of the container.
FIG. 7 additionally shows two containers 18, 20 in the shape of a cup having an annular flange 26 along the rim. One container 18 has an intact seal in the form of a tear-off sheet 22. The tear-off sheet 22 is removed on the other container 20, which contains disinfection liquid 24. The cups 18, 20 are shaped such that they may be received in the container 4, so that the annular flange 26 engages the upper edge of the container. In the applied position of the case lid 4, the O-ring engages the annular flange 26 on the disposable container 20 (FIG. 8), thereby forming a tight connection between the container 20 and the lid 8. In the same position, the lens baskets 14 extend down into the liquid in the container 20.
Disinfection of contact lenses 16 takes place by placing them in the lens baskets 14, following which, the disposable container 20 is placed in the container 4, and the sheet 22 across the mouth on the disposable container 20 is torn off. The lid 8 is then threaded onto the container, thereby causing the lens baskets 14 containing the contact lenses 16 to be immersed into the disinfection liquid 24 which is present in the container 20, and which has maintained its optimum effect till now. After treatment is completed, the lid 8 is screwed off the container 4, and the disposable container 20 with the spent liquid is discarded. If a two-liquid disinfection system is used, the container with the neutralization liquid is then inserted into the container 4 after tearing-off of the disposable sheet 22, and the lid 8 is screwed on again, following which the neutralization process takes place.
If the user of the contact lenses is particularly careful with the cleaning of his lenses, the lenses are rubbed before being disinfected. The mechanical action results in a better cleaning of the bacterial film and of other impurities on the lenses than the disinfection which takes place merely by immersing the lenses into disinfection liquid. A little liquid is necessary for the rubbing, which is performed by a finger. The spent liquid from the preceding disinfection may be used for this purpose, or sterile brine. As the lid and container of the lens case are sealed, it is thus possible to store the liquid after the disinfection until rubbing is to be performed. After rubbing, the disposable container with the spent liquid is discarded, a new one is inserted, and the actual disinfection of the contact lenses takes place.
It is common to the use of the disinfection system 1 of the invention that both the disposable container 18 and the spent disinfection liquid 24 present in the container are discarded after the completion of the disinfection of the contact lenses 16.
If the disinfection system 1 also comprises holding means in the form of lens baskets 19 as well as a cover 28, these parts are discarded together with the container 18 and the spent disinfection liquid 24. If the user does not want to exchange the cover 28 and the lens baskets 19 after each disinfection of contact lenses, these parts may be used again together with the embodiment of the disinfection system which does not comprise these parts. Hereby, the precise exchange frequency of lens baskets 19 and cover 28 desired by the user, may be achieved.
As an additional safeguard against contamination in connection with the disinfection process, the cover 28 may also be provided with a tear-off film on the side facing the container mouth, said film being removed immediately before the application of the cover on the container.
Thus, the described disinfection system provides a method of ensuring that the correct amount of disinfection liquid is used for the disinfection of contact lenses, thereby eliminating the danger of bacterial growth in the case container.
The use of the method and the lens case of the invention in connection two two-liquid disinfection systems reduces the risk of inserting non-neutralized contact lenses practically to zero, as the user can always observe how far he is in the cleaning process on the basis of the shape and color of the containers.
If the disposable containers, containing H 2 O 2 and neutralization liquid, respectively, are made of a material of different appearance and/or shape, e.g., with different colors, the risk of inserting non-neutralized contact lenses is reduced additionally, as the user, by looking at the disposable container, can see what it contains, e.g., a red container contains H 2 O 2 , and a green container contains neutralization liquid. The different container colors are relevant particularly where the user has torn off the seal on both containers at the same time, it being of paramount importance to the user to know which container contains which.
What remains is thus how to keep the lid 8 and the lens baskets 14 free of bacteria in the lens case 2 for use together with the disinfection system 1. However, exchange of the baskets will hardly be necessary, as the disinfection takes place in liquid with unreduced strength. As an additional safeguard, the lid 8, the O-ring 13 and the lens baskets 14 may be made of a material resistant to boiling, thereby allowing these to be boiled, optionally in a weak brine solution, which kills the bacterial cultures that might have survived the disinfection with the disinfection liquid.
The disposable containers may be made with a quite small thickness in an inexpensive manner, e.g., as vacuum formed sheet elements, as these will be protected by the container of the lens case in use. Further, they are usually supplied in multi-unit boxes with a suitable strong package optionally formed as a dispenser, or suitable in such a one, suspended from a wall or the like.
It is contemplated that the containers 18 of the disinfection system and the lens baskets 19, 14 as well as the special lens case 2 may be made of recyclable plastics materials to the greatest possible extent. | 4y
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This is a U.S. national stage application of PCT Application No. PCT/CN2011/000363 under 35 U.S.C. 371, filed Mar. 7, 2011 in Chinese, claiming the priority benefit of Chinese Application No. 201020160039.7, filed Mar. 13, 2010, and Chinese Application No. 201010173404.2, filed Apr. 28, 2010, both of which are hereby incorporated by reference.
FIELD OF THE INVENTION
The present invention relates to the technology of solid waste disposal, and more specially relates to a method and equipment for the disposal of municipal solid waste (hereinafter referred to as MSW) or organic waste.
DESCRIPTION OF THE PRIOR ART
With growing economic development and constant expansion of city scale, municipal solid waste and organic waste are rapidly increasing like a flood. Now garbage besiege appear in many cities of many countries, affecting sustainable economic development and restricting urban development. MSW and organic waste contain many harmful ingredients that, if not handled properly, will pollute environment and threaten human health. Presently, MSW disposal technology mainly includes garbage sorting and comprehensive utilization, sanitary landfill, composting (biochemical) and incineration. Among these technologies, garbage sorting has not been implemented in many countries because it requires public participation. Even if garbage is sorted and comprehensively utilized, there is still an amount of 40-50% of waste requiring incineration or landfill. In most parts of the world, sanitary landfill is adopted to dispose urban MSW, which occupies a lot of land resource, releases a lot of greenhouse gas, pollutes land and groundwater and destroys living environment of mankind Composting technology only makes use of about 40% organic substances, and the rest 60% still needs the disposal of incineration or landfill which also meets the problem of secondary pollution. Incineration of MSW seemingly reduces the amount and resource of garbage. However, in fact, this method transfers solid pollutant to the atmosphere in the form of flue gas that will return to the earth by cross-ventilation and gravitational force or in the form of acid rain, affecting human health and environment with the carbon dioxide emissions from the greenhouse effect. Incineration also easily generates dioxin—highly carcinogenic toxic substance—to pollute environment and harm human health. Even with flue gas purification system, waste incineration still lacks effective and reliable end purification technology to eliminate dioxin pollution.
Dioxin is a chlorine-containing strongly toxic organic chemical. It is a very stable, water-insoluble, colorless and odorless liposoluble material, and it easily bioaccumulates. Since the microorganisms and the hydrolysis in natural world hardly impact the molecular structure of dioxin, dioxin in the environment is difficult to eliminate by natural degradation. Dioxin known as the “poison of the century” has been claimed to be as a category one carcinogen by the international cancer research centers. Garbage, industrial organic waste and medical waste will produce dioxin in the incineration process in the following ways: a. the formation of dioxin in the burning process by molecular rearrangement, free-radical condensation, dechlorination or other molecule reaction of chlorine-containing precursors such as chlorinated plastics, chlorinated pesticides/herbicide/wood preservative/bleach/food, and polychlorinated biphenyl; b. when the combustion is not sufficient, chlorine-containing garbage will not be completely burned, resulting in excessive unburned substances in the flue gas that will form dioxin when meeting strong catalytic substances such as copper chloride, iron chloride, nickel oxide, aluminum oxide and other heavy metals; c. dioxin contained in the fuel is not destroyed and still exists in the flue gas after burning; d. residual carbon, oxygen, hydrogen, chloride, etc. in solid fly ash are catalyzed in the surface of fly ash and synthesize intermediate material or dioxin, or precursors in vapor phase are catalyzed in the surface of fly ash and synthetize dioxin; e. when the flue gas drops from the high temperature to low temperature between 250° C. to 500° C., the decomposed dioxin will be resynthesized; f. dioxin is composed by unknown reasons. MSW commonly contains chlorine source, organic matter and heavy metals. Therefore, the flue gas, fly ash and slag out of incinerator often contain dioxin. Studies have shown that the precursor concentration, chlorine concentration, temperature, oxygen content, sulfur content, and heavy metals as the existence of unconscious catalysts produce significant impact on the generation and emission of dioxin in the process of MSW incineration. Even with the most advanced incineration technology and equipment, waste incineration inevitably produces dioxin-contaminated environment. Therefore, complete combustion of garbage can only be under the conditions of >6% excessive oxygen, otherwise more pollution will be produced. Excessive oxygen is one of the conditions to form dioxin. The dioxin concentration is greatly increased in the environment of excessive oxygen while it is decreased in oxygen-deficient environment. No oxygen, no dioxin can be synthesized. The flue gas must contact the metal heating surfaces of the superheater, boiler, heat exchangers, and air preheater equipment during incineration. So all the metal heating surfaces will become the catalytic media of dioxin. Complete deacidification is difficult to realize during incineration. The residual carbon, oxygen, hydrogen, chlorine, fly ash and a certain amount of dioxin precursors still exist in the flue gas, and will inevitably resynthesize dioxin at a lower temperature outside the incinerator. There is a certain amount of dioxin in the flue gas of garbage incinerator. It is difficult to eliminate dioxin from the flue gas. It will pollute the environment with the flue gas emissions. Since it is hard to degrade and has a half-life of 273 years, dioxin is basically considered nondegradable. It will be accumulated more and more in people's living environment and in human body. Serious dioxin pollution appears in many countries that mainly adopt garbage incineration, to which sufficient attention should be paid.
In summary, the disposal of garbage incineration is not a good way. Sanitary landfill occupies land, releases greenhouse gases and pollutes environment. Waste sorting and composting have to face the problem that a part of garbage cannot be fully used. However, the headache garbage besiege must be solved. Therefore, humanity is eager to get perfect technical solutions for the garbage disposal.
SUMMARY OF THE INVENTION
The object of the present invention is to overcome the problems of garbage landfill and incineration that harm human living environment with dioxin contamination by disclosing a technology to dispose MSW and organic waste by gasification-liquefaction technology that effectively inhibit the formation of pollutants including dioxin. No greenhouse gas emits throughout the process of disposal. Therefore, the technology can solve the problem of dioxin contamination, protect ecological environment, and convert the garbage, organic waste to a chemical raw material or clean energy.
One method of the present invention to dispose MSW by gasification—gasification technology, comprising calcium oxide assisting plasma gasification technology wherein the MSW or organic waste, after pretreatment, is dehydrated and separated, thus reducing the moisture and mineral content, decreasing the unnecessary components in raw material in the furnace, increasing calorific value, lowering electric consumption of plasma gasification furnace and improving the quality of syngas. After pretreatment, MSW or organic waste is fed into a plasma gasifier via a CO 2 sealed feeding device. CO 2 seal can effectively prevent air from entering through feeding inlet into the gasifier as well as prevent the syngas in the furnace from escaping through the feeding inlet, but not obstruct feeding material. A plasma gasifier is provided with a drying section, a pyrolysis section and a gasification section in the order of upper, middle and lower segments. The MSW or organic waste, after dried and pyrolyze in the furnace, becomes waste carbon, and is fed in gasification zone for gasification reaction with the decomposer of the water steam injected into the gasification zone from a plasma torch, and generates hydrogen-rich syngas in which CO and H 2 are the main components. A plasma torch is provided in the gasification section and uses water steam as gasifying agent and working gas. The water steam is heated by the plasma torch to >4200° C., so that water molecules are decomposed completely, generating H*, H 2 *, HO*, O*, O 2 * and H 2 O* that are then directly sprayed on the MSW carbon in the gasification section. The MSW carbon serves as hydrogen and oxygen absorber to generate CO and H 2 . The clinker is melted to a liquid slag at 1300˜1600° C. environment in melted slag zone of the furnace, and discharged via a water seal to a slag pool. The calcium oxide assisting plasma gasification is adopted. A carbonator reaction chamber is provided in the gasification system. The heat emitted by carbon dioxide absorbing calcium oxide to generate calcium carbonate can provide supplementary heat source for the gasification, drying and preheating of new waste materials fed in the furnace, so as to reduce the energy consumption of the plasma torch. The pyrolysis gas produced at the pyrolysis section of a plasma gasifier is introduced into a carbonator reaction chamber, and then as a carrier gas, the pyrolysis gas carries calcium oxide, calcium carbonate mixture and heat into the drying section of the plasma gasifier. Also serving as a dechlorination or desulfurizing agent, calcium oxide can remove dioxin precursors, chlorides and sulfides in the environment of excessive calcium oxide. Then the pyrolysis gas is introduced into a gas-solid separator wherein calcium oxide and calcium carbonate are separated, and then fed into the gasification section of the plasma gasifier. In the environment of 1000 to 1300° C., methane, gaseous tar, ethylene, ethane, water steam, etc., are pyrolyzed and chemically reacted, thoroughly decomposing dioxin at the same time. By circulated gasification, the waste in the furnace is completely decomposed, and produces a hydrogen-rich syngas wherein high-quality hydrogen and carbon monoxide are main components. The hydrogen-rich syngas is outputted out of the plasma gasifier, and after cooling in an exhaust heat boiler, deacidified and dedusted in gas purifying equipment that consists of an absorption reactor, a cyclone duster and a bag dust collector. Then carbon dioxide in the syngas is absorbed by potassium carbonate solution in CO 2 absorbing tower to generate potassium bicarbonate. The syngas after removing carbon dioxide is fed in a methanol synthesis reactor to produce methanol and the potassium bicarbonate is fed to the regeneration reactor to decompose to potassium carbonate solution and carbon dioxide by heating. The decomposed potassium carbonate solution is then returned to the CO 2 absorbing tower for recycling and the decomposed carbon dioxide is fed into the carbonation reaction chamber of the gasification system for carbonation reaction with calcium oxide, thus assisting heat to waste gasification while preventing greenhouse gases from emitting. Hydrogen-rich syngas is catalyzed to a methanol product in the methanol synthesis reactor. The methanol product is mixed with limewater in a mixed absorber of end purifying device to allow the residual contaminants including dioxin, carbon dioxide to be absorbed by the limewater. Then the methanol is separated out through a distillation column, and unreacted gas is returned to the methanol synthesis reactor for a circulating reaction. After decontamination, limewater is fed by a circulating pump back to the mixed absorber for recycling. The exhaust is returned to the plasma gasifier for recycling, forming a closed loop production system. In this method, the operating temperature of drying section is controlled at between 120 to 300° C.; the operating temperature of pyrolysis section is controlled between 300 to 1000° C.; the operating temperature of gasification zone is controlled at between 1000 to 1300° C.; the operating pressure in the gasifying furnace is controlled at between −30 Pa˜+5 kPa. When clinker is melted to liquid slag and discharged, a liquid slag zone is provided between gasification zone and slag port, and a plasma torch is provided in the slag zone. The operating temperature of the slag zone is controlled at between 1300˜1600° C. The leachate generated in waste pretreatment process is fed into a digester for biogas production by anaerobic fermentation. The biogas is then fed into the plasma gasifier for decomposition, and biogas residue can be used as fertilizer. Selected inorganic materials sorted in the pretreatment process are resorted for scrap metal recycling. Then non-metallic inorganic materials are ground and mixed with calcium carbonate, calcium oxide separated from the gasification system to produce non-fired bricks. The slag discharged from plasma gasifier into water sealed slag pool becomes vitreous particles that can be directly used as building material. The fly ash collected from the bag filter is then treated through melting kiln and the slag can be directly used as building material.
According to the above method, the amount of calcium oxide that is input to carbonation reaction chamber is determined by 1.2˜1.5 times the total amount of molar number of carbon dioxide, chloride, sulfide, and fluoride in the reaction chamber. The molar number of carbon dioxide is determined by real input amount and detected content in pyrolysis gas. The molar number of chloride, sulfide, and fluoride is determined by the analysis of organic waste in sampled waste.
In the above-mentioned method, the waste is disposed by the way of plasma gasification such as water steam, without inputting oxygen or air to the gasifier, so that waste is gasified in anoxic environments. The rate of excessive oxide in syngas is none that can effectively inhibit the production of dioxin. In the carbonation reaction chamber, directly mixing calcium oxide powder with the pyrolysis gas can effectively remove the precursors of dioxin, chlorinated organics, desulfurize and cure in the absorbent, thereby reducing the probability of dioxin formation. The pyrolysis gas is circulated in the plasma gasifier. When the pyrolysis gas is circulated to the gasification section at 1000˜1300° C., dioxin will be thoroughly destroyed. In the plasma gasifier, waste materials are first pyrolyzed, after volatile constituents are escaped, go through gasification reaction with a plasma active material of the water steam at over 4200° C. and fixed carbon. In the gasification zone at 1000˜1600° C., the fixed carbon will be completely gasified. Using a closed loop production process, MSW and organic waste are absorbed with limewater in terminal purification operation and converted into methanol products for human needs.
A MSW gasification-liquefaction disposal system of the present invention including a plasma gasification equipment, comprises a preprocessing device, a CO 2 gas sealed feeding means ( 13 ), a plasma gasifier ( 23 ), a plasma torch ( 24 ), a gas-solid separator ( 17 ), a circulating fan ( 18 ), a heat exchanger a ( 20 ), a carbonation reaction chamber ( 2007 ), a waste heat boiler ( 27 ), an absorption reactor ( 32 ), a cyclone duster ( 31 ), a bag dust collector ( 38 ), CO 2 absorber ( 42 ), a regeneration tower ( 46 ), a methanol synthesis reactor ( 52 ), a mixed absorber ( 55 ), a distillation column ( 62 ), a decontaminator ( 58 ), a circulating pump ( 60 ), a methanol tank ( 65 ) and connecting ducts. Among them: the preprocessing device comprises a waste storage pit ( 2 ) and a sorting machine ( 3 ). The inner space of plasma gasifier ( 23 ) is provided with a drying section, a pyrolysis section and a gasification section. In the drying section are provided waste material inlet, heat carried gas inlet and pyrolysis gas outlet. The output interface of heat carried gas is provided in the pyrolysis section. The input interface of pyrolysis gas is provided in the gasification section. The output interface of syngas is provided in the joint position of pyrolysis section and the gasification section. The plasma torch ( 24 ) is provided in the gasification zone in the lower part of the plasma gasifier ( 23 ). The heat exchanger a ( 20 ) consists of an atmolysis chamber, a heat exchange chamber and a gas collection chamber. The input interface of pyrolysis gas is provided in the atmolysis chamber. The output interface of heat carried gas is provided in the heat change chamber. The output interface of pyrolysis gas is provided in the gas collection chamber. The carbonation reaction chamber ( 2007 ) communicates directly with the heat exchange chamber in the heat exchanger a ( 20 ). The carbonation reaction chamber ( 2007 ) is provided with the input interface of heat carried gas, inputting apparatus of the calcium oxide and input interface of carbon dioxide. A CO 2 absorber ( 42 ) is provided with the input interface of the syngas, the output interface of syngas, KHCO 3 output interface and the input interface of the K 2 CO 3 solution. A regeneration tower ( 46 ) is provided with the input interface of KHCO 3 , the output interface of CO 2 and the output interface of the K 2 CO 3 solution.
A waste storage pit ( 2 ) is constantly connected with a sorting machine ( 3 ) through a crane grab ( 1 ). The sorting machine ( 3 ) is constantly connected with a feed inlet of the CO 2 gas sealed feeding means ( 13 ) of plasma gasification equipment by the belt conveyor or screw feeders. The outlet of CO 2 gas sealed feeding means ( 13 ) is connected to the waste inlet of the plasma gasifier ( 23 ). The output interface of heat carried gas of the plasma gasifier ( 23 ) is connected to the input interface of heat carried gas of carbonation reaction chamber ( 2007 ). The output interface of heat carried gas of the heat exchanger ( 20 ) is connected to the inlet heat carried gas of the plasma gasifier ( 23 ). The outlet of heat carried gas of the plasma gasifier ( 23 ) is connected to the mixture inlet of the gas-solid separator ( 17 ). The gaseous substance outlet of the gas-solid separator ( 17 ) is connected to the input interfaces of pyrolysis gas of the heat exchanger a ( 20 ) through the circulating fan ( 18 ). The output interface of pyrolysis gas of the heat exchanger a ( 20 ) is connected to the input interface of pyrolysis gas of the plasma gasifier ( 23 ). The output interface of syngas of the plasma gasifier ( 23 ) is connected to the input interface of syngas of the waste heat boiler ( 27 ). The output interface of syngas of the waste heat boiler ( 27 ) is connected to the input interface of syngas of an absorption reactor ( 32 ). The output interface of syngas of the absorption reactor ( 32 ) is connected to the mixture input interface of syngas of a cyclone duster ( 31 ). The solid substance outlet of the cyclone duster ( 31 ) is connected to the connecting pipe of syngas input interface of a absorption reactor ( 32 ). The solid gaseous substance outlet of the cyclone duster ( 31 ) is connected to the syngas input interface of a bag dust collector ( 38 ). The output interface of syngas of the bag dust collector ( 38 ) is connected to syngas input interface of a CO 2 absorbing tower ( 42 ). The output interface of KHCO 3 of the CO 2 absorbing tower ( 42 ) is connected to an input interface of KHCO 3 of a regeneration tower ( 46 ). The CO 2 output interface of the regeneration tower ( 46 ) is connected to the input interface of CO 2 of a carbonation reaction chamber ( 2007 ). The output interface of K 2 CO 3 solution of a regenerating tower ( 46 ) is connected to the input interface of K 2 CO 3 solution of the CO 2 absorbing tower ( 42 ). The output interface of syngas of the CO 2 absorbing tower ( 42 ) is connected to the induction port of compressor i ( 51 ). The exhaust port of the compressor i ( 51 ) is connected to the virgin gas port of a methanol synthesis reactor ( 52 ). The methanol gas outlet of the methanol synthesis reactor ( 52 ) is connected to methanol gas inlet of the mixed absorber ( 55 ). The mixture outlet of mixed absorber ( 55 ) is connected to the mixture input interface of a distillation column ( 62 ). The unreacted gas outlet of distillation column ( 62 ) of is connected to the return-air interface of the methanol synthesis reactor ( 52 ) via an unreacted gas pipeline ( 61 ) and compressor b ( 56 ). The methanol product outlet of the distillation column ( 62 ) is connected to a methanol tank ( 65 ). The limewater outlet of distillation column ( 62 ) is connected to the input interface of decontaminator ( 58 ). The limewater outlet of decontaminator ( 58 ) is connected to the water inlet of a circulating pump ( 60 ). The water outlet of the circulation pump ( 60 ) is connected to the limewater inlet of a mixed absorber ( 55 ).
In the system described above, the preprocessing device further comprises a spiral moisture expelling and feeding means ( 10 ) and a digester ( 9 ). The spiral moisture expelling and feeding means ( 10 ) performs dual functions of water squeeze and material feeding. The spiral moisture expelling and feeding means ( 10 ) is provided between the sorting machine ( 3 ) and CO 2 gas sealed feeding means ( 13 ). The waste material outlet of the sorting machine ( 3 ) is constantly connected to the hopper of spiral moisture expelling and feeding means ( 10 ) through a belt conveyor ( 8 ). The material outlet of spiral moisture expelling and feeding means ( 10 ) is connected to the material inlet of CO 2 gas sealed feeding means ( 13 ) through a duct a ( 12 ). The outlet of CO 2 gas sealed feeding means ( 13 ) is connected to the material inlet of the plasma gasifier ( 23 ) through a duct b ( 14 ). The leachate interfaces of the waste storage pit ( 2 ), the sorting machine ( 3 ) and spiral moisture expelling and feeding means ( 10 ) are connected to the material outlet of the digester ( 9 ). The biogas outlet of the digester ( 9 ) is connected to the gasification zone of the plasma gasification furnace ( 23 ).
In the above-described system, an induced-draft fan ( 40 ) and a carbon monoxide conversion reactor ( 41 ) are also provided between a bag dust collector ( 38 ) and a CO 2 absorber ( 42 ). The output interface of syngas of the bag dust collector ( 38 ) is connected to the suction inlet of a induced-draft fan ( 40 ). The air outlet of induced-draft fan ( 40 ) is connected to the syngas input interface of a CO shift reactor ( 41 ). The output interface of syngas of the CO shift reactor ( 41 ) is connected to syngas input interface of CO 2 absorbing tower ( 42 ). A compressor a ( 44 ) and a syngas storage tank ( 48 ) are also provided between the CO 2 absorbing tower ( 42 ) and a compressor i ( 51 ). The output interface of syngas of the CO 2 absorbing tower ( 42 ) is connected to the induction port of the compressor a ( 44 ). The exhaust port of the compressor a ( 44 ) is connected to the input interface of a syngas storage tank ( 48 ). The output interface of syngas storage tank ( 48 ) is connected to the suction port of the compressor i ( 51 ).
In the system described above, an exhaust gas interface and the ammonia plant are provided in an unreacted gas pipeline ( 61 ) at the terminal end of the methanol synthesis system, and meanwhile an exhaust feedback pipeline ( 30 ) is provided between the plasma gasifier ( 23 ) and purification equipment at the terminal end. The exhaust gas interface of the unreacted gas pipeline ( 61 ) is, via a control valve, respectively connected to the exhaust feedback pipeline ( 30 ) of the plasma gasifier ( 23 ) and material inlet interface of synthetic ammonia equipment. The exhaust gas outlet of synthetic ammonia equipment is connected to the exhaust feedback pipeline ( 30 ) of the plasma gasifier ( 23 ).
Another MSW gasification-liquefaction disposal system of the present invention including a plasma gasification equipment, comprises a preprocessing device, a CO 2 gas sealed feeding means ( 13 ), a plasma gasifier ( 23 ), a plasma torch ( 24 ), a circulating fan ( 18 ), a heat exchanger b ( 21 ), a waste heat boiler ( 27 ), an absorption reactor ( 32 ), a cyclone duster ( 31 ), a bag dust collector ( 38 ), a hydrogenation absorber ( 49 ), a methanol synthesis reactor ( 52 ), a mixed absorber ( 55 ), a distillation column ( 62 ), a decontaminator ( 58 ), a circulating pump ( 60 ), a methanol tank ( 65 ) and connecting ducts. Among them: the preprocessing device comprises a waste storage pit ( 2 ) and a sorting machine ( 3 ). The inner space of plasma gasifier ( 23 ) is provided with drying section, pyrolysis section and gasification section. In the drying section are provided waste material inlet and pyrolysis gas outlet. The input interface of pyrolysis gas is provided in the gasification section. The output interface of syngas is provided in the joint position of pyrolysis section and the gasification section. The plasma torch ( 24 ) is provided in gasification section in the lower part of the plasma gasifier ( 23 ). Heat exchanger b ( 21 ) consists of atmolysis chamber, heat exchange chamber and gas collection chamber. The input interface of pyrolysis gas is provided in the atmolysis chamber. The input interface and output interface of syngas are provided in the heat change chamber. The output interface of pyrolysis gas is provided in the gas collection chamber. The waste storage pit ( 2 ) is constantly connected with the sorting machine ( 3 ) through the crane grab ( 1 ). The sorting machine ( 3 ) is constantly connected with a feed inlet of the CO 2 gas sealed feeding means ( 13 ) of plasma gasification equipment by the belt conveyor or screw feeders. The outlet of CO 2 gas sealed feeding means ( 13 ) is connected to the inlet of plasma gasifier ( 23 ). The pyrolysis gas outlet of the plasma gasifier ( 23 ) is connected to the input interface of pyrolysis gas of the heat exchanger b ( 21 ) through the circulating fan ( 18 ). The output interface of pyrolysis gas of the heat exchanger b ( 21 ) is connected to the input interface of pyrolysis gas in the gasification section of the plasma gasifier ( 23 ). The output interface of syngas of the plasma gasifier ( 23 ) is connected to the input interface of syngas of the heat exchanger b ( 21 ). The output interface of syngas of the heat exchanger b ( 21 ) is connected to the input interface of syngas of the waste heat boiler ( 27 ). The output interface of syngas of the waste heat boiler ( 27 ) is connected to the input interface of syngas of the absorption reactor ( 32 ). The output interface of syngas of the absorption reactor ( 32 ) is connected to the mixture input interface of syngas of the cyclone duster ( 31 ). The solid substance outlet of the cyclone duster ( 31 ) is connected to the connecting pipe of syngas input interface of the absorption reactor ( 32 ). The solid gaseous substance outlet of the cyclone duster ( 31 ) is connected to the syngas input interface of the bag dust collector ( 38 ). The output interface of syngas of the bag dust collector ( 38 ) is connected to the induction port of a compressor a ( 44 ). The exhaust port of the compressor a ( 44 ) is connected to the input interface of a syngas storage tank ( 48 ). The output interface of the syngas storage tank ( 48 ) is connected to the input interface of a hydrogenation mixer ( 49 ). The output interface of syngas of the hydrogenation mixer ( 49 ) is connected to the suction inlet of a compressor i ( 51 ). The exhaust port of the compressor i ( 51 ) is connected to the virgin gas port of a methanol synthesis reactor ( 52 ). The methanol gas outlet of the methanol synthesis reactor ( 52 ) is connected to a methanol gas inlet of the mixed absorber ( 55 ). The mixture outlet of the mixed absorber ( 55 ) is connected to the mixture input interface of a distillation column ( 62 ). The unreacted gas outlet of the distillation column ( 62 ) of is connected to the return-air interface of the methanol synthesis reactor ( 52 ) via an unreacted gas pipeline ( 61 ) and the compressor b ( 56 ). The methanol product outlet of the distillation column ( 62 ) is connected to a methanol tank ( 65 ). The limewater outlet of distillation column ( 62 ) is connected to the input interface of a decontaminator ( 58 ). The limewater outlet of the decontaminator ( 58 ) is connected to the water inlet of a circulating pump ( 60 ). The water outlet of the circulation pump ( 60 ) is connected to the limewater inlet of a mixed absorber ( 55 ). In the system described, the preprocessing device further comprises a spiral moisture expelling and feeding means ( 10 ) and the digester ( 9 ). The spiral moisture expelling and feeding means ( 10 ) is provided between a sorting machine ( 3 ) and CO 2 gas sealed feeding means ( 13 ). The waste material outlet of sorting machine ( 3 ) is constantly connected to the hopper of spiral moisture expelling and feeding means ( 10 ) through a belt conveyor ( 8 ). The material outlet of spiral moisture expelling and feeding means ( 10 ) is connected to the material inlet of CO 2 gas sealed feeding means ( 13 ) through a duct a ( 12 ). The outlet of CO 2 gas sealed feeding means ( 13 ) is connected to the material inlet of a plasma gasifier ( 23 ) through a duct b ( 14 ). The waste storage pit ( 2 ), a sorting machine ( 3 ) and the leachate interface of spiral moisture expelling and feeding means ( 10 ) are connected to the material inlet of the digester ( 9 ). The biogas outlet of the digester ( 9 ) is connected to the gasification section of the plasma gasifier ( 23 ). An induced-draft fan ( 40 ) is also provided between a waste heat boiler ( 27 ) and an absorption reactor ( 32 ). The syngas outlet of a waste heat boiler ( 27 ) is connected to the air inlet of an induced-draft fan ( 40 ). The air outlet of the induced-draft fan ( 40 ) is connected to the syngas input interface of an absorption reactor ( 32 ). The unreacted gas pipeline ( 61 ) at the terminal end of methanol synthesis system is provided with the exhaust gas interface and the ammonia plant. Meanwhile, an exhaust feedback pipeline ( 30 ) is provided between the plasma gasifier ( 23 ) and the device at the terminal end of the methanol synthesis system. The exhaust gas interface of an unreacted gas pipeline ( 61 ) is, via a control valve, respectively connected to the exhaust feedback pipeline ( 30 ) of the plasma gasifier ( 23 ) and material inlet interface of the ammonia plant. The exhaust gas outlet of ammonia plant is connected to the exhaust feedback pipeline ( 30 ) of the plasma gasifier ( 23 ).
In the equipment of above-mentioned system: A waste heat boiler ( 27 ), an absorption reactor ( 32 ), a cyclone duster ( 31 ), a bag dust collector ( 38 ), a CO 2 absorber ( 42 ), a regeneration tower ( 46 ), a methanol tank ( 65 ), a distillation column ( 62 ) and a decontaminator ( 58 ) are manufactured using conventional techniques. The methanol synthesis reactor ( 52 ) can be manufactured using known technology or the technology of China Patent ZL 200710166618.5 “Electro-catalytic synthesis reactor”.
An equipment of gasification-liquefaction disposal for MSW, Comprises the gasification means that consist of a plasma gasifier ( 23 ), a plasma torch ( 24 ), a circulating fan ( 18 ), a heat exchanger b ( 21 ) and connecting ducts. The plasma gasifier ( 23 ) is divided into a drying section ( 23 -I), a pyrolysis section ( 23 -II) and a gasification zone ( 23 -III) from top to bottom. The drying section ( 23 -I), pyrolysis section ( 23 -II) and gasification zone ( 23 -III) communicates directly. The plasma torch ( 24 ) is provided in the furnace wall of the gasification section ( 23 -III). A waste material inlet ( 2302 ) and a pyrolysis gas outlet ( 2303 ) are provided in the upper part of the drying section ( 23 -I). The input interface a ( 2309 ) of pyrolysis gas is provided in the gasification section ( 23 -III). A slag hole ( 2307 ) is provided in the lower part of gasification section ( 23 -III). An output interface a ( 2304 ) of syngas is provided in the joint position of the pyrolysis section ( 23 -II) and gasification section ( 23 -III). The heat exchanger b ( 21 ) consists of an atmolysis chamber ( 2102 ), a heat exchange chamber ( 2104 ), a heat exchange bundle ( 2105 ) and a gas collection chamber ( 2107 ). An atmolysis chamber ( 2102 ), a heat exchange chamber ( 2104 ) and a gas collection chamber ( 2107 ) are arranged into upper, middle and lower parts. A heat exchange chamber ( 2104 ) is in the middle. An atmolysis chamber ( 2102 ), a heat exchange chamber ( 2104 ) and a gas collection chamber ( 2107 ) are inside a steel shell. The exterior of the steel shell is covered with an insulation material. The atmolysis chamber ( 2102 ) and the heat exchange chamber ( 2104 ) are separated by an upper baffle. The heat exchange chamber ( 2104 ) and gas collection chamber ( 2107 ) are separated by a lower baffle. A heat exchange bundle ( 2105 ) is provided in the heat exchange chamber ( 2104 ), with both ends intersecting the atmolysis chamber ( 2102 ) and the gas collection chamber ( 2107 ). The atmolysis chamber ( 2102 ), bundle ( 2105 ) and gas collection chamber ( 2107 ) constitute a return passage of pyrolysis gas. The input interface b ( 2101 ) of pyrolysis gas is provided in an atmolysis chamber ( 2102 ). The heat change chamber ( 2104 ) is provided with an input interface ( 2108 ) of syngas and output interface b ( 2103 ) of syngas. The output interface ( 2109 ) of pyrolysis gas is provided in a gas collection chamber ( 2107 ). The pyrolysis gas outlet ( 2303 ) in drying section of the plasma gasifier ( 23 ) is connected to the air inlet of a circulating fan ( 18 ). The air outlet of the circulating fan ( 18 ) is connected to the input interface b ( 2101 ) of pyrolysis gas in the atmolysis chamber. The output interface ( 2109 ) of pyrolysis gas in the gas collection chamber of the heat exchanger b ( 21 ) is connected to input interface a ( 2309 ) of pyrolysis gas in the gasification section of the plasma gasifier ( 23 ). The output interface a ( 2304 ) of syngas in plasma gasifier ( 23 ) is connected to an input interface ( 2108 ) of syngas in a heat exchange chamber of the heat exchanger b ( 21 ). The gas output interface b ( 2103 ) of syngas in the heat exchange chamber of the heat exchanger b ( 21 ) is connected to a downstream device. The soot door ( 2110 ) of the heat exchanger b ( 21 ) is connected to a fly ash returning interface ( 2306 ) in the plasma gasifier ( 23 ). In this device: when a calcium oxide torch ( 79 ) is provided in a furnace wall of the plasma gasifier ( 23 ), the calcium oxide torch ( 79 ) is provided in a furnace wall of the gasification section ( 23 -II) of the plasma gasifier ( 23 ). The calcium oxide torch ( 79 ) is provided with a CO 2 input interface ( 7901 ) and a calcium oxide input interface ( 7902 ). Meanwhile, a gas-solid separator ( 17 ) is provided between pyrolysis gas outlets in drying section ( 2303 ) of the plasma gasifier ( 23 ) and an air inlet of the circulating fan ( 18 ). The pyrolysis gas outlet ( 2303 ) in the drying section of the plasma gasifier ( 23 ) is connected to a mixture inlet ( 1702 ) of a gas-solid separator ( 17 ). The gaseous material outlet ( 1703 ) of the gas-solid separator ( 17 ) is connected to the air inlet of the circulating fan ( 18 ). The solid material outlet ( 1701 ) of the gas-solid separator ( 17 ) is connected to the input interface of calcium oxide ( 7902 ) of the calcium oxide torch ( 79 ). The CO 2 input interface ( 7901 ) of the calcium oxide torch ( 79 ) is connected to the CO 2 gas pipeline. The gasification section ( 23 -III) of the plasma gasifier ( 23 ) is also provided with a fly ash returning interface ( 2306 ), a biogas input interface ( 2308 ) and an exhaust gas input interface ( 2305 ). The heat exchange chamber ( 2104 ) of the heat exchanger b ( 21 ) is also provided with a soot-blowing opening ( 2106 ) and a soot door ( 2110 ). The soot door ( 2110 ) of the heat exchanger b ( 21 ) is connected to the fly ash returning interface ( 2306 ) in the plasma gasifier ( 23 ). The soot-blowing opening ( 2106 ) of the heat exchanger b ( 21 ) is connected to a soot-blowing fan. The air inlet of soot-blowing fan is connected to the syngas pipeline. The air outlet of soot-blowing fan is connected to a soot-blowing opening ( 2106 ) of the heat exchanger b ( 21 ).
The beneficial effect of the present invention is the gasification-liquefaction disposal for MSW can realize zero emissions and avoid dioxin contamination. No pollutant is released throughout the disposal process and the produced methanol products can be used as chemical raw materials or industrial fuel. The economic benefits obtained are much higher than waste incineration power. Waste incineration produces large amount of carbon dioxide gas and other pollutant emissions, harming the environment severely. The technology of the present invention does not emit smoke and does not pollute the environment. Waste incineration will inevitably produce highly toxic dioxin that is difficult to eliminate and is harmful to human health when the flue gas is released to the atmosphere. The present invention can inhibit the formation of dioxin. Even if an extremely small amount of dioxin appears, it is also easy to clear by purification equipment at a terminal end. Compared with waste landfill disposal, the technology of the present invention does not release any pollutants and greenhouse gases. Waste landfill disposal transfers the pollution to underground, emits large quantities of greenhouse gases, contaminates soil and groundwater, endangering the health of the human body and also affecting the next generations of human being. The present invention utilizes waste as a resource to produce clean energy, reduce energy pressure and meanwhile generate economic benefits. After the disposal is commercialized, government will not bear any cost. The waste landfill is not only a waste of resources, but also a bottomless pit for its cost, giving a large financial pressure on government. The land occupied by the technology of the present invention is much less than waste landfill. The present invention is suitable for harmless resource disposal of municipal solid waste, rural solid waste, medical waste, industrial high polymer waste, agricultural and forestry wastes, composting remainder and waste in waste sorting sites.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a process flow diagram of gasification-liquefaction disposal for MSW of the present invention.
FIG. 2 is a system diagram of calcium oxide assisted gasification-liquefaction disposal for MSW of the present invention.
FIG. 3 is a system diagram of hydrogenation gasification-liquefaction disposal for MSW of the present invention.
FIG. 4 is the detailed part of zone I in FIG. 2 or the detailed part in zone I of FIG. 3 .
FIG. 5 is the detailed part of zone II-a in FIG. 2 .
FIG. 6 is the detailed part of zone III-a in FIG. 2 .
FIG. 7 is the detailed part of zone IV in FIG. 2 or the detailed part in zone IV of FIG. 3 .
FIG. 8 is the detailed part of zone II-b in FIG. 3 and also a structural plan of gasification equipment in MSW disposal system.
FIG. 9 is a structural plan of another gasification equipment in MSW disposal system.
FIG. 10 is the detailed part of zone III-b in FIG. 3 .
In the figure: 1 . crane grab, 2 . waste storage pit, 3 . sorting machine, 4 . inorganic material silo, 5 . belt conveyer, 6 . magnetic separator, 7 . waste metal silo, 8 . belt conveyer, 9 . digestor, 10 . spiral moisture expelling and feeding means, 11 . biogas pipeline, 12 . waste duct a, 13 . gas sealed feeding means, 14 . waste duct b, 15 . air pump, 16 . material-blowing fan, 17 . gas-solid separator, 18 . circulating fan, 19 . interface of calcium oxide supplementation, 20 . heat exchanger a, 21 . heat exchanger b, 22 . air pipe, 23 . plasma gasifier, 24 . plasma torch, 25 . high-temperature deodorizer, 25 ′. air deodorizing and purifying device, 26 . heat exchanger c, 27 . waste heat boiler, 28 . syngas pipeline, 29 . fly ash pipeline, 30 . exhaust feedback pipeline, 31 . cyclone duster, 32 . absorption reactor, 33 . absorbent silo, 34 . material-blowing fan, 35 . melting kiln, 36 . absorbent circulating pipe, 37 . absorbent feedback pipe, 38 . bag dust collector, 39 . material-blowing fan, 40 . induced-draft fan, 41 . CO shift reactor, 42 . CO 2 absorber, 43 . supplementing pipe of absorption solution, 44 . compressor a, 45 . circulating pipe of absorption solution, 46 . regeneration tower, 47 . circulating pump of absorption solution, 48 . syngas tank, 49 . hydrogenation mixer, 50 . supplementing interface of hydrogen gas, 51 . compressor i, 52 . methanol synthesis reactor, 53 . sedimentation tank, 54 . water pump, 55 . mixed absorber, 56 . compressor b, 57 . condenser, 58 . decontaminator, 59 . solidified slag, 60 . circulating pump, 61 . unreacted gas pipeline, 62 . distillation column, 63 . synthetic ammonia reactor, 64 . compressor c, 65 . methanol tank, 66 . condensor, 67 . ammonia separator, 68 . liquid ammonia tank, 69 . air pump, 70 . waste leachate pool, 71 . water pump, 72 . air curtain, 73 . material-unloading platform, 74 . exhaust fan, 75 . control valve, 76 . control valve, 77 . control valve, 78 . control valve, 79 . calcium oxide torch 301 . hopper, 302 . inorganic material outlet, 303 . waste outlet, 901 . taphole, 902 . biogas outlet, 903 . feed inlet, 1001 . driving shaft, 1002 . hopper, 1003 . spiral shaft, 1004 . spiral shell, 1301 . feed inlet, 1302 . CO 2 supplementing interface, 1303 . CO 2 gas seal, 1304 . storage silo, 1305 . spiral shell, 1306 . spiral shaft, 1307 . driving shaft, 1701 . solid material outlet, 1702 . mixed material outlet, 1703 . gaseous material outlet, 2001 . input interface of pyrolysis gas, 2002 . atmolysis chamber, 2003 . input interface of heat carried gas, 2004 . output interface of pyrolysis gas, 2005 . gas collection chamber, 2006 . heat exchange chamber, 2007 . carbonation reaction chamber, 2008 . CO 2 input interface, 2009 . calcium oxide torch, 2010 . output interface of heat carried gas, 2101 . input interface of pyrolysis gas b, 2102 . atmolysis chamber, 2103 . syngas output interface, 2104 . heat exchange chamber, 2105 . heat exchange bundle, 2106 . soot-blowing opening, 2107 . gas collection chamber, 2108 . syngas input interface, 2109 . output interface of pyrolysis gas, 2110 . soot door, 2301 . inlet of heat carried gas, 2302 . inlet of waste material, 2303 . outlet of pyrolysis gas, 2304 . syngas output interface, 2305 . exhaust input interface, 2306 . fly ash feedback interface, 2307 . taphole, 2308 . biogas input interface, 2309 . a input interface a of pyrolysis gas, 2310 . output interface of heat carried gas, 2311 . furnace wall, 23 -I. drying section, 23 -II. pyrolysis section, 23 -III. gasification section, 2501 . input interface of air odor, 2502 . syngas outlet, 2503 . outlet of deodored air, 2504 . syngas input interface, 2601 . air outlet, 2602 . hot air inlet, 2701 . syngas inlet, 2702 . syngas outlet, 3101 . gaseous material outlet, 3102 . input interface of mixed material, 3103 . solid material outlet, 3201 . syngas outlet, 3202 . input interface of absorbent, 3203 . input interface of syngas, 3801 . syngas output interface, 3802 . fly ash outlet, 3803 . syngas input interface, 4101 . syngas input interface, 4102 . syngas output interface, 4201 . syngas output interface, 4202 . syngas input interface, 4203 . K 2 CO 3 input interface of K 2 CO 3 solution, 4204 . KHCO 3 input interface of KHCO 3 , 4601 . KHCO 3 output interface of KHCO 3 , 4602 . K 2 CO 3 output interface of K 2 CO 3 solution, 4603 . output interface of CO 2 , 4801 . syngas input interface, 4802 . syngas output interface, 4901 . input interface of hydrogen gas, 4902 . syngas output interface, 4903 . syngas input interface, 5201 . material gas inlet, 5202 . returned gas interface, 5203 . output interface of methanol gas, 5301 . sewage inlet, 5302 . suction pipe, 5203 . slag tapping, 5501 . methanol gas inlet, 5502 . limewater inlet, 5503 . mixture inlet, 5701 . limewater outlet, 5702 . limewater inlet, 5801 . limewater outlet, 5802 . sewage outlet, 5803 . input interface of limewater, 6201 . input interface of mixture, 6202 . limewater outlet, 6203 . outlet of methanol product, 6204 . outlet of unreacted gas, 6301 . material inlet, 6302 . ammonia outlet, 6601 . input interface of ammonia, 6602 . output interface of ammonia mixture, 6701 . input interface of ammonia mixture, 6702 . output interface of liquid ammonia, 6703 . exhaust outlet, 7901 . CO 2 CO 2 input interface, 7902 . input interface of calcium oxide.
In FIG. 4 , 5 , 6 , 7 , 8 , 9 , 10 : A is correspondingly connected to the {circle around (A)}; B is correspondingly connected to the {circle around (B)}; C is correspondingly connected to {circle around (C)}; D is correspondingly connected to {circle around (D)}; E is correspondingly connected to {circle around (E)}; F is correspondingly connected to {circle around (F)}; H is correspondingly connected to {circle around (H)}; J is correspondingly connected to {circle around (J)}.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Example 1
In the embodiment shown in FIG. 1 , MSW or organic waste in the waste storage pit was dehydrated to some extent by the way of fermentation, and then through separation organic matter waste separated was fed into a spiral moisture expelling and feeding means. In the process of conveying through the screw feeder, some amount of water was removed further by extrusion. Then the waste material was fed into a plasma gasifier through a CO 2 gas sealed device. The MSW, after dried in drying section of plasma gasifier and pyrolyzed in pyrolysis section of plasma gasifier, became MSW carbon and entered the gasification section for gasification reaction with the decomposer of the water steam injected into the gasification section from a plasma torch, and completed gasification and generates hydrogen-rich syngas in which CO and H 2 are the main components. The operating temperature of drying section was at between 120 to 300° C.; the operating temperature of pyrolysis section is between 300 to 1000° C.; the operating temperature of gasification section is at between 1000 to 1300° C.; the operating temperature of melted slag zone is at between 1300 to 1600° C.; the operating pressure in the gasification furnace is controlled at between 0˜5 kPa. A plasma torch is provided in the gasification section, and the heat required by the gasification in the furnace is mainly provided by the plasma torch and the exothermic reaction of plasma active chemicals and MSW carbon. As the working steam for gasifying agent and the plasma torch, the water steam is heated to >4200° C. by the plasma torch, so that water molecules are decomposed completely, generating H*, H 2 *, HO*, O*, O 2 * and H 2 O* that are then directly sprayed on the MSW carbon in the gasification section. The MSW carbon serves for hydrogen and oxygen absorber to generate CO and H 2 . Clinker is melted to a liquid slag at 1300˜1600° C. environment in melted slag zone of the furnace, and discharges via a water seal to the slag pool and becomes vitreous grains. The heat emitted when calcium oxide absorbs CO 2 to produce calcium carbonate is provided as an assistant heat source for gasification and an assisting plasma gasification. A carbonization reaction chamber is provided in the gasification system. Calcium oxide and CO 2 were inputted into the carbonization reaction chamber for carbonization reaction. Calcium oxide also serves for dechlorinator or desulfurizer that introduces the pyrolysis gas generated in pyrolysis section of the plasma gasifier into the carbonation reaction chamber. In the environment of the existence of excessive 1.2 times calcium oxide, dioxin precursors, chlorides and sulfides were removed. Then pyrolysis gas was also used as a carrier gas to carry calcium oxide, calcium carbonate mixture and heat into the drying section of the plasma gasifier, thus providing heat for the drying and preheating of the new materials into the furnace waste. Then the pyrolysis gas was led out of the furnace and into the gas-solid separator to separate calcium oxide and calcium carbonate. Then pyrolysis gas was fed into the heat exchanger by the circulation fan, and after indirect heating in the heat exchanger, fed into the gasification section of the plasma gasifier. In the environment of 1000 to 1300° C., methane, gaseous tar, ethylene, ethane, water steam, etc. in pyrolysis gas were pyrolyzed and chemically reacted. In addition, dioxin was thoroughly disintegrated. By circulated gasification, the waste in the furnace was completely decomposed, and produced a hydrogen-rich syngas in which hydrogen and carbon monoxide were main components. The hydrogen-rich syngas was led from the plasma gasifier into a waste heat boiler to recover waste heat to produce steam. Meanwhile the syngas cooled down to about 232° C. and after cooling through exhaust heat boiler was fed to absorption reactor for deacidification. With calcium oxide or calcium hydroxide as the absorbent, chlorides, sulfides, fluorides, and other acidic pollutants were removed from the syngas. Then through the cyclone duster, the absorber was separated and returned to the absorption reactor for recycling. Then the syngas removed fly ash by using bag dust collector. After deacidification and dedusting, the syngas was fed to a CO 2 absorber to absorb carbon dioxide in the syngas with potassium carbonate solution, then the potassium bicarbonate generated by potassium carbonate solution absorbing carbon dioxide was fed to a regeneration reactor. By heating, potassium bicarbonate was decomposed into potassium carbonate solution and carbon dioxide. The decomposed potassium carbonate solution was returned to CO 2 absorbing tower for recycling and the decomposed carbon dioxide was fed to carbonation reaction chamber for carbonation reaction. The syngas after removing carbon dioxide was fed into a syngas tank through compressor a. Out of the syngas tank, syngas was fed through the compressor to a methanol synthesis reactor to produce methanol. The hydrogen-rich syngas was catalyzed and synthesized to methanol product in the methanol synthesis reactor. Then the methanol gas was fed to a mixed absorber to mix with limewater, so that the residual contaminants including dioxin and carbon dioxide was absorbed by lime. Then through distillation, methanol was separated and the unreacted gas was returned to the methanol synthesis reactor for recycling reaction. Limewater after decontamination was fed back to mixed absorber for recycling use by a circulating pump. The exhaust was fed by a control valve to the plasma gasifier for recycling or synthetic ammonia equipment to produce liquid ammonia to remove nitrogen gas and form a closed loop production system. In this embodiment, the leachate generated in MSW pretreating process was fed into a digester to produce biogas by anaerobic fermentation. The biogas was fed into the plasma gasifier for decomposition and the biogas residue was used as fertilizer. Selected inorganic materials sorted in the pretreatment process were resorted for scrap metal recycling. Then non-metallic inorganic materials were ground and mixed with calcium carbonate, calcium oxide separated from the gasification system to produce non-fired bricks. The slag discharged from plasma gasifier into water sealed slag pool became vitreous particles that can be directly used as building material. The fly ash collected from the bag filter was then treated through melting kiln and the slag can be directly used as building material. The steam water mixture removed from the methanol synthesis reactor was fed into the waste heat boiler to produce steam that can serve as working steam for plasma torch and steam power generation. In the present embodiment, when the fractional ratio of hydrogen in the syngas produced in the plasma gasifier was not up to the requirements of methanol synthesis, add an operation of carbon monoxide conversion in the previous stage of CO 2 absorbing tower to increase the proportion of hydrogen in the syngas, or conduct hydrogenation to meet the requirements of syngas. Methanol synthesis can use conventional synthesis reactor or the electro-catalytic synthesis reactor specified in Chinese Patent No. 200710166618.5. When using conventional synthesis reactor, the synthesis of methanol uses Cu/Zn/Al catalyst at operating pressure of 3 to 15 Mpa and at operating temperature of 210 to 280° C. When using electro-catalytic synthesis reactor, the synthesis of methanol uses Cu/Zn/Al catalyst at operating pressure of 0˜1 Mpa and at operating temperature 120 to 400° C.
Example 2
As shown in the system diagram of FIG. 2 and detailed drawings in FIGS. 4 , 5 , 6 , 7 of the present invention, a MSW gasification-liquefaction disposal system comprises: a MSW pretreating zone (zone I in FIG. 2 ), a plasma gasification zone (zone II-a of FIG. 2 ), a syngas purification zone (zone III- 1 of FIG. 2 ) and a zone of methanol synthesis and a terminal purification zone (zone IV of FIG. 2 ). The system comprises a material-unloading platform ( 73 ), a waste storage pit ( 2 ), a crane grab ( 1 ), a sorting machine ( 3 ), spiral moisture expelling and feeding means ( 10 ), CO 2 gas sealed feeding means ( 13 ), a plasma gasifier ( 23 ), a plasma torch ( 24 ), a gas-solid separator ( 17 ), a circulating fan ( 18 ), a carbonation reaction chamber ( 2007 ), a heat exchanger ( 20 ), a waste heat boiler ( 27 ), an absorption reactor ( 32 ), a cyclone duster ( 31 ), a bag dust collector ( 38 ), an induced-draft fan ( 40 ), a CO shift reactor ( 41 ), a CO 2 absorber ( 42 ), a regeneration repercussion tower ( 46 ), a compressor a ( 44 ), a syngas tank ( 48 ), a compressor ( 51 ), a methanol synthesis reactor ( 52 ), a mixed absorber ( 55 ), a distillation column ( 62 ), a compressor b ( 56 ), a methanol output tank ( 65 ), an asynthetic ammonia reactor ( 63 ) and connecting ducts. Among which: the material-unloading platform comprise an unloading lane and a vehicle command room; an unloading lane, a vehicle command room, a waste storage pit ( 2 ) and a crane grab ( 1 ) were provided in steel-concrete structure buildings; An air curtain was provided in the entrance of garbage truck in these buildings. An air outlet of exhaust fan ( 74 ) on the roof was connected to input interface of air odor ( 2501 ) of high-temperature deodorizer ( 25 ) through air pipe ( 22 ). An outlet of deodored air ( 2503 ) of high-temperature deodorizer ( 25 ) was connected to an hot air inlet ( 2602 ) of the heat exchanger c ( 26 ). Spiral moisture expelling and feeding means ( 10 ) consisted of a hopper ( 1002 ), a driving shaft ( 1001 ), a spiral shaft ( 1003 ) and a spiral shell ( 1004 ). The hopper ( 1002 ) was provided over a spiral shell ( 1004 ). The spiral shell ( 1004 ) is therein provided with a spiral shaft ( 1003 ) that can perform rotation, water squeezing and material pushing with a driving shaft ( 1001 ). The material outlet of spiral moisture expelling and feeding means ( 10 ) is provided in the front end of spiral shell ( 1004 ). CO 2 gas sealed feeding means ( 13 ) consists of a storage silo ( 1304 ), a CO 2 gas seal ( 1303 ), a spiral shell ( 1305 ), a spiral shaft ( 1306 ), a driving shaft ( 1307 ), a transmission case and a motor. A storage silo ( 1304 ) is provided over a spiral shell ( 1305 ) and with CO 2 gas sealed material. The material outlet of storage silo ( 1304 ) communicates with the material inlet of a spiral shell ( 1305 ). The spiral shell ( 1305 ) is therein provided with the spiral shaft ( 1306 ) that performs the function of material pushing. The material outlet of CO 2 gas sealed feeding means ( 13 ) is in the front end of a spiral shell ( 1305 ). The inner space of plasma gasifier ( 23 ) is divided into the drying section ( 23 -I), the pyrolysis section ( 23 -II) and the gasification section ( 23 -III); The drying section ( 23 -I) is provided with an inlet of waste material ( 2302 ), an inlet of heat carried gas ( 2301 ) and an outlet of pyrolysis gas ( 2303 ). The pyrolysis section ( 23 -II) is provided with output interface of the heat carried gas ( 2310 ) and the gasification section ( 23 -III) is provided with input interface a of pyrolysis gas ( 2309 ). A taphole ( 2307 ) is provided in the bottom of gasification section ( 23 -III) and a melted slag zone is provided between the gasification section ( 23 -III) and taphole ( 2307 ). Syngas output interface a ( 2304 ) is provided in the joint position between the pyrolysis section ( 23 -II) and gasification section ( 23 -III). A plasma torch ( 24 ) is provided in gasification section ( 23 -III) in the lower part of the plasma gasifier ( 23 ). A heat exchanger a ( 20 ) consists of an atmolysis chamber ( 2002 ), a heat exchange chamber ( 2006 ) and a gas collection chamber ( 2005 ). The input interface ( 2001 ) of pyrolysis gas is provided in the atmolysis chamber ( 2002 ). The output interface ( 2003 ) of heat carried gas is provided in the heat change chamber ( 2006 ). The output interface ( 2004 ) of pyrolysis gas is provided in the gas collection chamber ( 2005 ). The carbonation reaction chamber ( 2007 ) is installed over the heat exchanger a ( 20 ). The carbonation reaction chamber ( 2007 ) communicates with the heat exchange chamber ( 2006 ) of the heat exchanger a ( 20 ). The carbonation reaction chamber ( 2007 ) is provided with the input interface ( 2010 ) of heat carried gas, calcium oxide torch ( 2009 ) of calcium oxide input interface ( 2008 ). The mixing absorber ( 55 ) consists of a mixed absorbing chamber, a Venturi water inlet, a methanol gas nozzle, a methanol gas inlet ( 5501 ), a limewater inlet ( 5502 ), a mixture inlet ( 5503 ) and the shell. The mixing absorbing chamber, Venturi water inlet and methanol gas nozzle are inside the shell. The mixing absorbing chamber is positioned after the Venturi water inlet, and methanol gas nozzle is positioned is before the Venturi inlet. The diameter of methanol gas nozzle gradually expands from spout to inlet. The length of methanol gas nozzle is 2.5 times the average diameter. The outer diameter of an orifice of a methanol gas nozzle is 0.7 to 0.8 times the inner diameter of Venturi water inlet. The methanol gas nozzle and Venturi water inlet are coaxially designed and the methanol gas nozzle extends the ⅓ length into the Venturi water inlet in the shell. A methanol gas inlet ( 5501 ) is connected to the inlet of methanol gas nozzle. A limewater inlet ( 5502 ) is provided in the shell between the Venturi water inlet and input interface of methanol gas. The mixture inlet ( 5503 ) is provided in the shell of mixed absorbing chamber. The waste storage pit ( 2 ) is constantly connected to a hopper ( 301 ) of a sorting machine ( 3 ) through a crane grab ( 1 ). The waste outlet ( 303 ) of a sorting machine ( 3 ) is constantly connected to the hopper ( 1002 ) of spiral moisture expelling and feeding means ( 10 ) through a belt conveyer ( 8 ). The material outlet of spiral moisture expelling and feeding means ( 10 ) is constantly connected to the material inlet of CO 2 gas sealed feeding means ( 13 ) through duct a ( 12 ). The material outlet of CO 2 gas sealed feeding means ( 13 ) is connected to waste material inlet of plasma gasifier ( 23 ) through duct b ( 14 ). The output interface ( 2310 ) of heat carried gas of the plasma gasifier ( 23 ) is connected to the input interface ( 2010 ) of the heat carried gas of a carbonation reaction chamber ( 2007 ). The output interface ( 2003 ) of heat carried gas of heat exchanger a ( 20 ) is connected to the inlet ( 2301 ) of heat carried gas of the plasma gasifier ( 23 ). The outlet ( 2303 ) of heat carried gas of the plasma gasifier ( 23 ) is connected to the mixture inlet ( 1702 ) of the gas-solid separator ( 17 ). The gaseous substance outlet ( 1703 ) of the gas-solid separator ( 17 ) is connected to the input interfaces ( 2001 ) of pyrolysis gas of heat exchanger a ( 20 ) through circulating fan ( 18 ). The output interface ( 2004 ) of pyrolysis gas of heat exchanger a ( 20 ) is connected to the input interface a ( 2309 ) of pyrolysis gas of the plasma gasifier ( 23 ). The solid material outlet ( 1701 ) of the gas-solid separator ( 17 ) is respectively connected to slag silo and calcium oxide torch ( 2009 ) through ducts. The interface of calcium oxide supplementation ( 19 ) and material-blowing fan ( 16 ) are provided in connecting ducts. The output interface a ( 2304 ) of syngas of the plasma gasifier ( 23 ) is connected to the syngas inlet ( 2701 ) of the waste heat boiler ( 27 ). The water supplementation interface of the waste heat boiler ( 27 ) is connected to water supplying equipment. The steam output interface of the waste heat boiler ( 27 ) is connected to steam supply pipe network. The soot door ( 29 ) of the waste heat boiler ( 27 ) is connected to fly ash returning interface ( 2306 ) in the plasma gasifier ( 23 ) through fly ash pipeline ( 29 ). The syngas outlet ( 2702 ) of the waste heat boiler ( 27 ) is connected to syngas input interface ( 3203 ) of the absorption reactor ( 32 ). The material outlet of the absorbent silo ( 33 ) is connected to absorbent input interface ( 3202 ) of the absorption reactor ( 32 ). The material pipe of absorbent input interface ( 3202 ) is also connected to the air outlet of the material-blowing fan ( 34 ). The air inlet of the material-blowing fan ( 34 ) is connected to the syngas pipeline ( 28 ). The syngas output interface ( 3201 ) of the absorption reactor ( 32 ) is connected to the mixture input interface ( 3102 ) of the cyclone duster ( 31 ). The solid substance outlet ( 3103 ) of the cyclone duster ( 31 ) is connected to the connecting ducts of the input interface ( 3203 ) of the absorption reactor ( 32 ). The solid gaseous substance outlet ( 3101 ) of the cyclone duster ( 31 ) is connected to the syngas input interface ( 3803 ) of the bag dust collector ( 38 ). The fly ash outlet ( 3802 ) of the bag dust collector ( 38 ) is connected to a melting kiln ( 35 ). The syngas output interface ( 3801 ) of the bag dust collector ( 38 ) is connected to the air inlet of the induced-draft fan ( 40 ). The air outlet of induced-draft fan ( 40 ) is connected to syngas input interface ( 4101 ) of the CO shift reactor ( 41 ). The syngas output interface ( 4102 ) of the CO shift reactor ( 41 ) is connected to the syngas input interface ( 4202 ) of the CO 2 absorbing tower ( 42 ). The output interface ( 4204 ) of KHCO 3 of the CO 2 absorbing tower ( 42 ) is connected to the input interface ( 4601 ) of KHCO 3 of the regeneration tower ( 46 ). The CO 2 output interface ( 4603 ) of the regeneration tower ( 46 ) is connected to the input interface ( 2008 ) of CO 2 of the carbonation reaction chamber ( 2007 ). The output interface ( 4602 ) of K 2 CO 3 solution of the regenerating tower ( 46 ) is connected to the input interface ( 4203 ) of K 2 CO 3 solution of the CO 2 absorbing tower ( 42 ). Syngas output interface ( 4201 ) of the CO 2 absorbing tower ( 42 ) is connected to syngas input interface ( 4801 ) of syngas tank through compressor a ( 44 ). Syngas output interface ( 4802 ) of the syngas storage tank ( 48 ) is connected to the suction port of the compressor i ( 51 ). The exhaust outlet of the compressor i ( 51 ) is connected to the material gas inlet ( 5201 ) of the methanol synthesis reactor ( 52 ). The methanol gas outlet ( 5203 ) of the methanol synthesis reactor ( 52 ) is connected to methanol gas inlet ( 5501 ) of the mixed absorber ( 55 ) through a decompression control valve. The mixture outlet ( 5503 ) of mixed absorber ( 55 ) is connected to mixture input interface ( 6201 ) of distillation column ( 62 ). Unreacted gas outlet ( 6204 ) of distillation column ( 62 ) is connected to the return-air interface ( 5202 ) of methanol synthesis reactor ( 52 ) through a control valve ( 76 ), unreacted gas pipeline ( 61 ) and compressor b ( 56 ). The methanol product outlet ( 6203 ) of the distillation column ( 62 ) is connected to the methanol tank ( 65 ). The limewater outlet ( 6202 ) of distillation column ( 62 ) is connected to the input interface ( 5803 ) of decontaminator ( 58 ). Sewage outlet ( 5802 ) of decontaminator ( 58 ) is connected to sedimentation tank ( 53 ). The limewater outlet ( 5801 ) of decontaminator ( 58 ) is connected to the water inlet of circulating pump ( 60 ). The water outlet of the circulation pump ( 60 ) is connected to the limewater inlet ( 5502 ) of a mixed absorber ( 55 ). Suction pipe ( 5302 ) is connected to the water inlet of water pump ( 54 ) in one side of sedimentation tank ( 53 ). The water outlet of water pump ( 54 ) is connected to the connecting ducts of limewater inlet ( 5502 ) of the mixed absorber ( 55 ). Unreacted gas outlet ( 6204 ) of distillation column ( 62 ) is connected to material inlet ( 6301 ) of the synthetic ammonia reactor ( 63 ) through the control valve ( 75 ) and the compressor c ( 64 ). Ammonia outlet ( 6302 ) of the synthetic ammonia reactor ( 63 ) is connected to the ammonia gas input interface ( 6601 ) of the condenser ( 66 ). Output interface of ammonia mixture ( 6602 ) of the condenser ( 66 ) is connected to input interface of ammonia mixture ( 6701 ) of ammonia separator ( 67 ). Output interface of liquid ammonia ( 6702 ) of the ammonia separator ( 67 ) is connected to liquid ammonia tank. Exhaust outlet ( 6703 ) of the ammonia separator ( 67 ) is connected to unreacted gas pipeline ( 61 ) through the control valve ( 78 ). Unreacted gas pipeline ( 61 ) is connected to exhaust input interface ( 2305 ) of plasma gasifier ( 23 ) through the control valve ( 77 ), the air pump ( 69 ) and exhaust feedback pipeline ( 30 ). The leachate interfaces of the waste storage pit ( 2 ), sorting machine ( 3 ) and spiral moisture expelling and feeding means ( 10 ) are connected to the material inlet of digester ( 9 ) through ducts. Biogas outlet ( 902 ) of the digester ( 9 ) is connected to biogas input interface ( 2308 ) of the plasma gasifier ( 23 ) through the biogas pipeline ( 11 ) and air pump ( 15 ).
Example 3
As shown in the system diagram of FIG. 3 and detailed drawings in FIGS. 4 , 7 , 8 , 9 of the present invention, a MSW gasification-liquefaction disposal system comprises: MSW pretreating zone (zone I in FIG. 3 ), a plasma gasification zone (zone II-b of FIG. 3 ), syngas purification zone (zone III-b of FIG. 3 ), a zone of methanol synthesis and terminal purification (zone IV of FIG. 3 ). The system comprises a material-unloading platform ( 73 ), a crane grab ( 1 ), a waste storage pit ( 2 ), a sorting machine ( 3 ), a digester ( 9 ), spiral moisture expelling and feeding means ( 10 ), CO 2 gas sealed feeding means ( 13 ), a plasma gasifier ( 23 ), a plasma torch ( 24 ), a circulating fan ( 18 ), a heat exchanger b ( 21 ), a waste heat boiler ( 27 ), an induced-draft fan ( 40 ), an absorption reactor ( 32 ), a cyclone duster ( 31 ), a bag dust collector ( 38 ), a compressor a ( 44 ), a syngas tank ( 48 ), a hydrogenation mixer ( 49 ), a compressor i ( 51 ), a methanol synthesis reactor ( 52 ), a mixed absorber ( 55 ), a decontaminator ( 56 ), a decontaminator ( 58 ), a circulating pump ( 60 ), a distillation column ( 62 ), a synthetic ammonia reactor ( 63 ), a compressor c ( 64 ), a methanol output tank ( 65 ), and connecting ducts. Of which: an exhaust fan ( 74 ) is provided over a waste storage pit ( 2 ) and a sorting machine ( 3 ), and its air outlet is connected to air deodorizing and purifying device 25 ′ through an air pipe ( 22 ); The inner space of plasma gasifier ( 23 ) is divided into a drying section ( 23 -I), a pyrolysis section ( 23 -II), a gasification section ( 23 -III); In the drying section ( 23 -I) are provided a waste material inlet ( 2302 ) and a pyrolysis gas outlet ( 2303 ); The input interface a ( 2309 ) of pyrolysis gas is provided in the gasification section ( 23 -III); A slag hole ( 2307 ) is provided in the bottom of gasification section ( 23 -III); A melted slag zone is provided between and taphole ( 2307 ); An output interface a ( 2304 ) of syngas is provided the joint position of pyrolysis section ( 23 -II) and gasification section ( 23 -III); A plasma torch ( 24 ) is provided in gasification section ( 23 -III) in the lower part of the plasma gasifier ( 23 ); Heat exchanger b ( 21 ) consists of atmolysis chamber ( 2102 ), heat exchange chamber ( 2104 ) and gas collection chamber ( 2107 ); Atmolysis chamber ( 2102 ), heat exchange chamber ( 2104 ) and gas collection chamber ( 2107 ) are isolated each other with baffles; Heat exchange bundle ( 2105 ) is provided in heat exchange chamber ( 2104 ) Between atmolysis chamber ( 2102 ) and gas collection chamber ( 2107 ); Atmolysis chamber ( 2102 ) is connected to gas collection chamber ( 2107 ) through heat exchange bundle ( 2105 ); The input interface b ( 2101 ) of pyrolysis gas is provided in the atmolysis chamber ( 2102 ); Heat change chamber ( 2104 ) is provided with syngas input interface ( 2108 ), syngas output interface b ( 2103 ), soot door ( 2110 ) and soot-blowing opening ( 2106 ). The output interface ( 2109 ) of pyrolysis gas is provided in the gas collection chamber ( 2107 ); Waste storage pit ( 2 ) is constantly connected to hopper ( 301 ) of sorting machine ( 3 ) through crane grab ( 1 ); The waste outlet ( 303 ) of sorting machine ( 3 ) is constantly connected to the hopper ( 1002 ) of spiral moisture expelling and feeding means ( 10 ) through belt conveyer ( 8 ); The material outlet of spiral moisture expelling and feeding means ( 10 ) is constantly connected to the material inlet of CO 2 gas sealed feeding means ( 13 ) through duct a ( 12 ); The material outlet of CO 2 gas sealed feeding means ( 13 ) is connected to waste material inlet of the plasma gasifier ( 23 ) through duct b ( 14 ); Pyrolysis gas outlet ( 2303 ) of plasma gasifier ( 23 ) is connected to the input interface b( 2101 ) of pyrolysis gas of heat exchanger b ( 21 ) through circulating fan ( 18 ); The output interface ( 2109 ) of pyrolysis gas of heat exchanger b ( 21 ) is connected to input interface a ( 2309 ) of pyrolysis gas in the gasification section of the plasma gasifier ( 23 ); The output interface a ( 2304 ) of syngas in the plasma gasifier ( 23 ) is connected to input interface ( 2108 ) of syngas in of heat exchanger b ( 21 ); The soot door ( 2110 ) of heat exchanger b ( 21 ) is connected to fly ash returning interface ( 2306 ) in the plasma gasifier ( 23 ) through ash discharging valve; Syngas output interface b ( 2103 ) of heat exchanger b ( 21 ) is connected to syngas hole ( 2701 ) of waste heat boiler ( 27 ); The soot door ( 29 ) of the waste heat boiler ( 27 ) is connected to fly ash returning interface ( 2306 ) in plasma gasifier ( 23 ) through fly ash pipeline ( 29 ); The syngas outlet ( 2702 ) of the waste heat boiler ( 27 ) is connected to syngas input interface ( 3203 ) of absorption reactor ( 32 ) through induced-draft fan ( 40 ); The material outlet of absorbent silo ( 33 ) is connected to absorbent input interface ( 3202 ) of absorption reactor ( 32 ); The material pipe of absorbent input interface ( 3202 ) is also connected to the air outlet of material-blowing fan ( 34 ); The air inlet of material-blowing fan ( 34 ) is connected to syngas pipeline ( 28 ); Syngas output interface ( 3201 ) of absorption reactor ( 32 ) is connected to the mixture input interface ( 3102 ) of cyclone duster ( 31 ); The solid substance outlet ( 3103 ) of cyclone duster ( 31 ) is connected to input interface ( 3203 ) of absorption reactor ( 32 ); The solid gaseous substance outlet ( 3101 ) of cyclone duster ( 31 ) is connected to syngas input interface ( 3803 ) of bag dust collector ( 38 ); Fly ash outlet ( 3802 ) of bag dust collector ( 38 ) is connected to melting kiln ( 35 ); Syngas output interface ( 3801 ) of bag dust collector ( 38 ) is connected to syngas input interface ( 4801 ) of syngas tank ( 48 ) through compressor a ( 44 ); Syngas output interface ( 4802 ) of syngas storage tank ( 48 ) is connected to input interface ( 4903 ) of hydrogenation mixer ( 49 ); Hydrogen input interface ( 4901 ) of hydrogenation mixer ( 49 ) is connected to the hydrogen supplying equipment; The output interface ( 4902 ) of syngas of hydrogenation mixer ( 49 ) is connected to the suction inlet of compressor i ( 51 ); The exhaust outlet of the compressor i ( 51 ) is connected to material gas inlet ( 5201 ) of methanol synthesis reactor ( 52 ); The methanol gas outlet ( 5203 ) of the methanol synthesis reactor ( 52 ) is connected to methanol gas inlet ( 5501 ) of the mixed absorber ( 55 ) through a decompression control valve; The mixture outlet ( 5503 ) of a mixed absorber ( 55 ) is connected to mixture input interface ( 6201 ) of distillation column ( 62 ); Unreacted gas outlet ( 6204 ) of distillation column ( 62 ) is connected to the return-air interface ( 5202 ) of a methanol synthesis reactor ( 52 ) through a control valve ( 76 ), a unreacted gas pipeline ( 61 ) and a compressor b ( 56 ); The methanol product outlet ( 6203 ) of the distillation column ( 62 ) is connected to methanol tank ( 65 ); The limewater outlet ( 6202 ) of the distillation column ( 62 ) is connected to the input interface ( 5803 ) of decontaminator ( 58 ); Sewage outlet ( 5802 ) of the decontaminator ( 58 ) is connected to the sedimentation tank ( 53 ); The limewater outlet ( 5801 ) of the decontaminator ( 58 ) is connected to the water inlet of the circulating pump ( 60 ); The water outlet of the circulation pump ( 60 ) is connected to the limewater inlet ( 5502 ) of mixed absorber ( 55 ); Unreacted gas outlet ( 6204 ) of the distillation column ( 62 ) is connected to a material inlet ( 6301 ) of the synthetic ammonia reactor ( 63 ) through a control valve ( 75 ) and a compressor c ( 64 ); an ammonia outlet ( 6302 ) of the synthetic ammonia reactor ( 63 ) is connected to the ammonia gas input interface ( 6601 ) of the condenser ( 66 ); an output interface of ammonia mixture ( 6602 ) of the condenser ( 66 ) is connected to input interface of ammonia mixture ( 6701 ) of the ammonia separator ( 67 ); Output interface of liquid ammonia ( 6702 ) of the ammonia separator ( 67 ) is connected to liquid ammonia tank; Exhaust outlet ( 6703 ) of the ammonia separator ( 67 ) is connected to unreacted gas pipeline ( 61 ) through the control valve ( 78 ); Unreacted gas pipeline ( 61 ) is connected to exhaust input interface ( 2305 ) of the plasma gasifier ( 23 ) through control valve ( 77 ), air pump ( 69 ) and the exhaust feedback pipeline ( 30 ); The leachate interfaces of the waste storage pit ( 2 ), the sorting machine ( 3 ) and spiral moisture expelling and feeding means ( 10 ) are connected to the material inlet of digester ( 9 ) through the ducts; Biogas outlet ( 902 ) of digester ( 9 ) is connected to biogas input interface ( 2308 ) of plasma gasifier ( 23 ) through biogas pipeline ( 11 ) and air pump ( 15 );
Example 4
As shown in the example of FIG. 8 , a MSW gasification-liquefaction disposal system mainly comprises a plasma gasifier ( 23 ), a plasma torch ( 24 ), a circulating fan ( 18 ), a heat exchanger b ( 21 ) and connecting ducts. Among which: the plasma gasifier ( 23 ) takes high-furnace structure; Furnace wall ( 2311 ) of the plasma gasifier ( 23 ) consists of a fireproof layer, an insulating layer, a heat retaining layer and a steel shell in an order from interior to exterior; The fireproof layer is cast with high alumina refractory bricks or bauxite cement concrete. The insulating layer is made of diatomite material. The heat retaining layer is made of alumina silicate refractory fibrous material. The insulating layer in gasification section can be replaced by the cooling layer. The cooling layer consists of a steel pipe, a steel plate, an upper header pipe and a lower header pipe to constitute a water cooling wall structure. The lower header pipe is provided with an access of cooling water. The upper header pipe is provided with an outlet of backwater interface. The cooling layer is connected with a circulating cooling water system through the cooling water interface and backwater interface (not shown in figures). The plasma gasifier ( 23 ) is divided into a drying section ( 23 -I), a pyrolysis section ( 23 -II) and a gasification zone ( 23 -III) from top to bottom. The drying section ( 23 -I), pyrolysis section ( 23 -II) and gasification zone ( 23 -III) communicate directly. A waste material inlet ( 2302 ) and a pyrolysis gas outlet ( 2303 ) are provided in the upper part of drying section ( 23 -I). Gasification section (-III) gasifier ( 23 ) is provided with input interface a ( 2309 ) of pyrolysis gas, the fly ash returning interface ( 2306 ) and connected with the biogas input interface ( 2308 ) and exhaust input interface ( 2305 ). A slag hole ( 2307 ) is provided in a side of lower part of the gasification section ( 23 -III). A melted slag zone is provided between and taphole ( 2307 ). An output interface a ( 2304 ) of syngas is provided in the joint position of pyrolysis section ( 23 -II) and gasification section ( 23 -III). The furnace walls of drying section ( 23 -I), pyrolysis section ( 23 -II) and gasification section ( 23 -III) are provided with a temperature sensor respectively. The furnace wall of gasification section ( 23 -III) is also provided with a peepsight. The furnace wall of drying section ( 23 -I) is also provided with a level sensor. The plasma torch ( 24 ) is provided in the furnace walls of gasification section ( 23 -III) and melted slag zone. Multiple plasma torches are arranged ringwise in many layers. The plasma torch ( 24 ) is provided with working gas input interface, coolant output interface and power supply interface. Working gas input interface is connected to steam pipe work through control valve and connecting ducts. Coolant input & output interfaces are connected to the coolant supplying and returning interfaces of coolant equipment respectively. Power supply interface is connected to the power supply output end of plasma controller. The heat exchanger b ( 21 ) consists of an atmolysis chamber ( 2102 ), a heat exchange chamber ( 2104 ), a heat exchange bundle ( 2105 ) and a gas collection chamber ( 2107 ). The atmolysis chamber ( 2102 ), heat exchange chamber ( 2104 ) and gas collection chamber ( 2107 ) are arranged into upper, middle and lower parts. The atmolysis chamber ( 2102 ), heat exchange chamber ( 2104 ) and gas collection chamber ( 2107 ) are inside a steel shell. The exterior of the steel shell is covered with insulation material. Atmolysis chamber ( 2102 ) and heat exchange chamber ( 2104 ) are separated by a upper baffle. The heat exchange chamber ( 2104 ) and gas collection chamber ( 2107 ) are separated by a lower baffle. The heat exchange bundle ( 2105 ) is provided in the heat exchange chamber ( 2104 ), with both ends intersecting atmolysis chamber ( 2102 ) and gas collection chamber ( 2107 ). Atmolysis chamber ( 2102 ), heat exchange bundle ( 2105 ) and gas collection chamber ( 2107 ) constitute the returning passage of pyrolysis gas. The input interface b ( 2101 ) of pyrolysis gas is provided in atmolysis chamber ( 2102 ). Heat exchange chamber ( 2104 ) is provided with syngas input interface ( 2108 ), syngas output interface b ( 2103 ), soot door ( 2106 ) and soot door ( 2110 ). The output interface ( 2109 ) of pyrolysis gas is provided in gas collection chamber ( 2107 ). The pyrolysis gas outlet ( 2303 ) in drying section of plasma gasifier ( 23 ) is connected to the air inlet of a circulating fan ( 18 ). The air outlet of the circulating fan ( 18 ) is connected to the input interface b ( 2101 ) of pyrolysis gas in atmolysis chamber. The output interface ( 2109 ) of pyrolysis gas in gas collection chamber of the heat exchanger b ( 21 ) is connected to input interface a ( 2309 ) of pyrolysis gas in the gasification section of plasma gasifier ( 23 ). The output interface a ( 2304 ) of syngas in plasma gasifier ( 23 ) is connected to the input interface ( 2108 ) of syngas in the heat exchange chamber of heat exchanger b ( 21 ). Syngas output interface b ( 2103 ) in the heat exchange chamber of the heat exchanger b ( 21 ) is connected into a downstream device. The soot door ( 2110 ) of the heat exchanger b ( 21 ) is connected to fly ash returning interface ( 2306 ) in the plasma gasifier ( 23 ). Soot-blowing opening ( 2106 ) of the heat exchanger b ( 21 ) is connected to an ash-blowing fan. The air inlet of ash-blowing fan is connected to syngas conveying pipeline and the air outlet of ash-blowing fan is connected to soot-blowing opening ( 2106 ) of the heat exchanger b ( 21 ).
Example 5
As shown in FIG. 9 of the present invention, this example has following changes on the basis of example 4: the furnace wall of pyrolysis section ( 23 -II) of plasma gasifier ( 23 ) is provided with a calcium oxide torch ( 79 ); calcium oxide torch ( 79 ) is provided with CO 2 input interface ( 7901 ) and input interface of calcium oxide ( 7902 ); a gas-solid separator ( 17 ) is provided between pyrolysis gas outlet ( 2303 ) in the drying section of the plasma gasifier ( 23 ) and a circulating fan ( 18 ). The pyrolysis gas outlet ( 2303 ) in the drying section of the plasma gasifier ( 23 ) is connected to the mixture inlet ( 1702 ) of the gas-solid separator ( 17 ). The gaseous material outlet ( 1703 ) of the gas-solid separator ( 17 ) is connected to the air inlet of the circulating fan ( 18 ). The solid material outlet ( 1701 ) of the gas-solid separator ( 17 ) is connected to the input interface of calcium oxide ( 7902 ) of calcium oxide torch ( 79 ). Interface of calcium oxide supplementation ( 19 ) is provided in the connecting duct between the solid material outlet ( 1701 ) of amidships gas-solid separator ( 17 ) and input interface of calcium oxide ( 7902 ) of calcium oxide torch ( 79 ). CO 2 input interface ( 7901 ) of calcium oxide torch ( 79 ) is connected to the CO 2 gas pipeline through a material-blowing fan ( 16 ). | 4y
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BACKGROUND
[0001] Embodiments of the disclosure relate generally to methods and structures for forming lightweight truss members and more particularly, to methods and structures for forming composite wing ribs and truss members.
[0002] Conventional aircraft wing construction generally comprises one or more spars that extend laterally relative to the longitudinal axis of the fuselage to support a plurality of longitudinally extending laterally spaced ribs that define the shape of the air foil. Vertical web portions of the ribs include structural elements configured to carry compressive and tensile loads to maintain the airfoil shape. A truss design for aircraft wing ribs is an efficient method of transferring and distributing loads throughout the wing structure. Additionally truss structures are used for bridges, floors and other supporting structures. At least some known truss structures are heavy due to the use of metal components and structural elements of the truss structure. A lightweight material may be used to make strong lightweight truss structures however, current composite ribs are complicated to manufacture and generally heavy in order to provide sufficient load transfer between the truss structural elements. The assembly of aircraft wings utilizing composite ribs in the wing have also proven to be difficult.
[0003] What are needed are methods and structures for providing lightweight support structures that facilitate fabrication of the truss structures and connecting components and reduce assembly time.
SUMMARY
[0004] In one embodiment, a structure for a for a composite truss includes a web formed of a plurality of sheets of composite material, each sheet including a first face and an opposing second face and each face including a length and a width. Each of the plurality of sheets are coupled to at least one other of the plurality of sheets face to face such that the length and width of each face substantially match the length and width of a face of an adjacent sheet. The plurality of sheets are formed to include an upper chord member, a lower chord member, and a plurality of web members extending therebetween. The structure also includes at least a first flange plate coupled to the web proximate an outer periphery of the web.
[0005] In yet another embodiment, a method of forming a composite structural member includes coupling a plurality of sheets of composite material face to face to form a web, shaping the web to form an upper cord and a lower chord, and forming a plurality of openings in the web to form a plurality of structural web members extending between the upper cord and lower chord. The method also includes coupling at least one flange plate to an outer peripheral edge of at least one of the upper cord and the lower chord.
[0006] In another embodiment, a method of forming an aircraft wing including a composite wing rib includes forming a wing rib wherein forming the wing rib includes forming a web from a plurality of composite sheets coupled together in a face to face orientation, forming a plurality of interconnected structural elements in the web including an upper chord member, a lower chord member, and a plurality of web members each defined by a plurality of openings formed in the web, and coupling a flange plate to a side of the wing rib proximate an outer peripheral edge of the wing rib, the flange plate including a laterally extending flange member. The method further includes assembling at least one wing rib to at least one of a forward spar and an aft spar and assembling a trailing edge skin to the spar and wing rib assembly using the laterally extending flange member. The method also includes assembling an upper and a lower center skin to the rib, spar and trailing edge skin assembly such that the center skin overlaps the trailing edge skin and attaching the leading edge skin to the wing assembly such that the leading edge skin overlaps the center skin and trailing edge skin assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a cut-away isometric view of an aircraft wing structure in accordance with an embodiment of the disclosure;
[0008] FIG. 2 is a side cross-sectional view of a truss rib assembly in accordance with an exemplary embodiment of the disclosure;
[0009] FIG. 3 is a section view of the truss rib assembly shown in FIG. 2 taken along section lines A-A;
[0010] FIG. 4 is a section view of the truss rib assembly shown in FIG. 2 taken along section lines B-B;
[0011] FIG. 5 is a section view of the truss rib assembly shown in FIG. 2 taken along section lines C-C.
[0012] FIG. 6 is a section view of the truss rib assembly shown in FIG. 2 taken along section lines D-D.
[0013] FIG. 7 is a section view of the truss rib assembly shown in FIG. 2 taken along section lines E-E.
[0014] FIG. 8 is a side cross-sectional view of a truss rib assembly in accordance with another exemplary embodiment of the disclosure.
DETAILED DESCRIPTION
[0015] The following detailed description illustrates the disclosure by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the disclosure, describes several embodiments, adaptations, variations, alternatives, and uses of the disclosure, including what is presently believed to be the best mode of carrying out the disclosure.
[0016] FIG. 1 is a cut-away isometric view of an aircraft wing structure 100 in accordance with an embodiment of the disclosure. In the exemplary embodiment, aircraft wing structure 100 includes a plurality of truss rib assemblies 102 extending in a forward direction 104 and an aft direction 106 between a leading edge 108 and a trailing edge 110 of aircraft wing structure 100 . Aircraft wing structure 100 also includes a forward wing spar 112 and an aft wing spar 114 extending from a fuselage of the aircraft (not shown). A lower wing covering section or skin 116 is joined to lower portions of truss rib assemblies 102 between leading edge 108 and trailing edge 110 . Similarly, an upper wing covering section or skin 118 is bonded to upper portions of truss ribs 102 between leading edge 108 and trailing edge 110 .
[0017] FIG. 2 is a side cross-sectional view of a truss rib assembly 102 in accordance with an exemplary embodiment of the disclosure. Although described as a rib for an aircraft airfoil such as a wing, it should be understood that the structures and methods of fabricating such structures may be used for other composite truss structures, for example, but not limited to joists, roof trusses, and bridge deck support members. In such embodiments, truss rib assemblies 102 are configured to receive one or more decking members for supporting the decking member thereon.
[0018] In the exemplary embodiment, truss rib assembly 102 comprises a composite truss structure. Truss rib assembly 102 includes an upper chord member 202 , a lower chord member, 204 , and a plurality of web members 206 extending therebetween. Each of upper chord member 202 , lower chord member, 204 , and web members 206 are formed of at least a first portion 202 and a second portion 204 mounted side by side. Each portion is formed of a fiber reinforced sheet material such as but not limited to plain weave (PW) or 5-hardness (5H) material. Fiber reinforced materials such as fiber glass, graphite, aromatic polyamide, such as but not limited to Aramid fiber epoxies or thermoplastics may also be used. Each portion is bonded or consolidated together. After the portions are bonded or consolidated together all of the truss structural elements form a box structure for each structural element. A cap 206 of the rib is open and becomes closed when the wing skin is bonded to the rib. A foam core may be utilized in the hollow spaces of the rib or truss.
[0019] In the exemplary embodiment, truss rib assembly 102 includes a lateral flange that is coupled to an outer periphery of truss rib assembly 102 that extends laterally away from truss rib assembly 102 . Lateral flange 208 may have a right hand portion and a left hand portion that each extend away from each other. In other embodiments, only a right hand or left hand flange is used. In the exemplary embodiment, flange 208 extends about the entire periphery of truss rib assembly 102 . In an alternative embodiment, truss rib assembly 102 only extends about a portion of the periphery of truss rib assembly 102 . A forward spar flange 210 and an aft spar flange 212 are formed similarly to lateral flange 208 , but circumscribe an inner periphery of each spar opening, 214 and 216 respectively. Flanges 208 , 210 , 212 illustrated at the spar and cap locations are configured to bond the rib and or rib sections to the individual skins to form skin assemblies and then bond the subassemblies into a completed wing. Each web opening 218 is circumscribed by a respective right hand and/or left hand flange 220 that extends inwardly into web opening 218 .
[0020] Although truss rib assembly 102 is illustrated as being fabricated as a unitary truss rib assembly 102 , it should be understood that truss rib assembly 102 may be fabricated from more that one separate piece to facilitate different wing assembly methods. The use of such composite truss ribs are not limited to aircraft wings, but also to floor or roof trusses on buildings, and bridge trusses that are manufactured in different locations and are erected on site.
[0021] FIG. 3 is a section view of truss rib assembly 102 taken along section lines A-A (shown in FIG. 2 ). In the exemplary embodiment, truss rib assembly 102 is formed by one or more sheets of composite material cutout to form upper chord member 202 , lower chord member, 204 , and web members 206 . The sheets are bonded together side by side and flanges applied to the periphery of truss rib assembly 102 and openings 218 . The flange at section A-A includes a left hand lateral portion 302 and a right hand lateral portion 304 each extending away from a centerline 306 of the composite sheets. The flange also includes a right hand flange portion 308 that extends into opening 218 and a left hand flange portion 310 that is complementary to flange portion 308 . In the exemplary embodiment, right hand flange portion 308 and left hand flange portion 310 are co-bonded to facilitate coupling the composite sheets together. Left hand lateral portion 302 and a right hand lateral portion 304 are configured to receive skin members in a bonding relationship to facilitate assembling a wing structure.
[0022] FIG. 4 is a section view of truss rib assembly 102 taken along section lines B-B (shown in FIG. 2 ). In the exemplary embodiment, truss rib assembly 102 taken along section lines B-B includes forward spar flange 210 on both sides of forward spar opening 214 and flanges 220 that extend into openings 218 and that facilitate coupling the composite sheets together.
[0023] FIG. 5 is a section view of truss rib assembly 102 taken along section lines C-C (shown in FIG. 2 ). In the exemplary embodiment, truss rib assembly 102 taken along section lines C-C includes a left hand flange half 502 and a right hand flange half 504 and flanges 220 that extend into openings 218 and that facilitate coupling the composite sheets together.
[0024] FIG. 6 is a section view of truss rib assembly 102 taken along section lines D-D (shown in FIG. 2 ). In the exemplary embodiment, truss rib assembly 102 taken along section lines D-D includes a left hand flange half 602 and a right hand flange half 604 and flanges 220 that extend into openings 218 and that facilitate coupling the composite sheets together.
[0025] FIG. 7 is a section view of truss rib assembly 102 taken along section lines E-E (shown in FIG. 2 ). In the exemplary embodiment, truss rib assembly 102 taken along section lines E-E includes aft spar flange 212 on both sides of aft spar opening 216 and on each of a left hand flange 702 and a right flange 704 . Truss rib assembly 102 also includes lateral flange 208 that extends along upper chord member 202 and lower chord member 204 . Aft spar flange 212 facilitates coupling truss rib assembly 102 to aft spar 114 and lateral flange 208 facilitates coupling covering sections or skin members to truss rib assembly 102 during assembly.
[0026] FIG. 8 is a side cross-sectional view of a truss rib assembly 800 in accordance with another exemplary embodiment of the disclosure. In the exemplary embodiment, truss rib assembly 800 is fabricated in three portions, a forward portion 802 , a center portion 804 , and an aft portion 806 . Each portion is formed of a composite sheet material such as PW or 5H material or a continuous fiber wound in channels oriented in a pattern representing a respective portion of an upper chord 810 , a lower chord 812 , and interconnecting structural members 814 forming the truss web. In some embodiments, it may be advantageous to form one or more of forward portion 802 , a center portion 804 , and an aft portion 806 of sheet material while other portions are formed of placed fib fabricated material. Assembly is accomplished by joining forward portion 802 , a center portion 804 , and an aft portion 806 . In one embodiment, forward portion 802 and center portion 804 are assembled to a forward spar (not shown) prior to being joined to each other and center portion 504 and an aft portion 506 are assembled to a rear spar (not shown) prior to being joined to each other.
[0027] The above-described methods of forming composite structural members and composite truss structures formed thereby are cost-effective and highly reliable. The methods and structures include composite sheet material formed and bonded together in a truss that includes an upper and lower chord as well as a web containing plurality of structural truss elements. The truss includes flange members for facilitating stiffening the truss and attaching skin or decking to the truss members. The composite sheet material is bonded or consolidated together to facilitates providing strength and stability. The lightweight truss simplifies handling with less or smaller support equipment. Accordingly, the methods and structures facilitate reducing weight and fabrication time, and improving strength and stiffness of the structural member in a cost-effective and reliable manner.
[0028] While embodiments of the disclosure have been described in terms of various specific embodiments, those skilled in the art will recognize that the embodiments of the disclosure can be practiced with modification within the spirit and scope of the claims. | 4y
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BACKGROUND OF THE INVENTION
The invention relates to a steering column for a motor vehicle, which comprises a jacket unit supporting a steering shaft rotatably about its longitudinal axis and a retaining part, which the jacket unit is secured non displaceably up to a limit value of a force acting onto the jacket unit parallel to the longitudinal axis of the steering shaft in the direction toward the front of the motor vehicle. If the limit value is exceeded, the jacket unit is displaceable parallel to the longitudinal axis in the direction toward the motor vehicle front. The jacket unit is connected with the retaining part, for one, across an energy absorption connection, which comprises at least one bending wire or strip that, upon a displacement of the jacket unit with respect to the retaining part parallel to the longitudinal direction toward the motor vehicle front, is deformed, and is connected, for another, across a break-away connection which, up to the limit value of the force, is closed and blocks a displacement of the jacket unit with respect to the retaining part and which is released if the limit value of the force is exceeded. The invention further relates to a method for the production of such a steering column.
Steering columns for motor vehicles are most often implemented such that they are adjustable so that the position of the steering wheel can be adapted to the seating position of the driver. Such adjustable steering columns are known in various embodiment forms. Apart from adjustable steering columns which are only adjustable in the length or height or inclination direction, steering columns are also known which are adjustable in the length as well as also the height or inclination direction.
As a safety measure in the event of a vehicle crash, it is known and conventional to realize in steering columns for motor vehicles the steering shaft together with a jacket unit, rotatably supporting the steering shaft, in a section adjoining the steering wheel-side end such that it is displaceable in the longitudinal direction of the steering column (=parallel to the longitudinal axis of the steering shaft) with the absorption of energy. A conventional implementation form provides for this purpose that a bracket unit, with respect to which in the opened state of the clamping mechanism the jacket unit is displaceable for setting the position of the steering column, is so connected with a mounting part attached on the vehicle chassis that the jacket unit with the absorption of energy is dislocatable with respect to the mounting part. Such a construction is shown, for example, in U.S. Pat. No. 5,517,877 A.
DE 28 21 707 A1 discloses a non-adjustable steering column in which the jacket tube rotatably supporting the steering shaft includes bilaterally projecting fins which had been connected on the chassis by securement blocks and bolts penetrating therethrough. In the event of a crash, the fins can become detached from the securement blocks, whereby a dislocation of the jacket tube is enabled. Between the securement blocks and the fins, U-shaped bending strips are herein provided on which deformation work is carried out during the dislocation of the jacket tube. The bending strips are enclosed in chambers of the fins and are in contact on opposing side walls of the chambers such that the rolling radius of the particular bending strip during its deformation is limited and predetermined.
An adjustable steering column comprising a jacket unit rotatably supporting the steering shaft and a bracket unit, with respect to which the jacket unit in the opened state of a securement device is displaceable for setting the position of the steering column at least in the longitudinal direction of the steering column, is disclosed in EP 0 598 857 B1. In the event of a crash, the jacket unit can be dislocated with respect to the bracket unit or with respect to a clamp bolt of the securement device in the longitudinal direction of the steering column. For the energy absorption, bending strips or bending wires are provided that are entrained with the jacket unit and placed about the clamp bolt, which strips or wires are deformed. One disadvantage of this solution is that the possible displacement path or the characteristic of the energy absorption in this device depends on the particular positioning length of the steering column.
Further, U.S. Pat. No. 5,961,146 A describes a steering column which in normal operation is only adjustable in the height direction. In a manner similar to that described above, a bending wire is provided curved in the shape of a U about the clamp bolt of the securement device, which in the event of a crash is entrained by the jacket unit dislocating with respect to the clamp bolt in the longitudinal direction of the steering column, whereby bending work is performed.
In the steering column disclosed in WO 2007/048153 A2, in the closed state of the securement device a retaining part is prevented by a securement part of the securement device from being displaced with respect to this securement part referred to the direction parallel to the steering shaft. The jacket unit can become dislocated in the longitudinal direction of the steering column with respect to the retaining part with the absorption of energy. For the energy absorption, a bolt is disposed on the retaining part which projects into an elongated hole of an energy absorption part disposed on the jacket unit and which, during its shift in the event of a crash, widens this elongated hole. To attain defined energy absorption, the material properties of the energy absorption part in the proximity of the elongated hole must be precisely defined such that they are reproducible.
Similar steering columns are also disclosed in EP 0 849 141 A1 and EP 1 464 560 A2. The retaining parts are guided by guide parts in the manner of a carriage such that they are displaceable in the longitudinal direction of the steering column. They are held under frictional closure with respect to the guide parts or plastically deform them with the consumption of energy. In the case of a frictionally engaged mounting, the clamping force of the securement device must be taken into account when considering the magnitude of the energy absorption. In a plastic deformation of the guide parts, their material properties must be implemented in a precisely defined reproducible manner.
A steering column of the above type is disclosed in DE 10 2008 034 807 B3. The retaining part is connected with the jacket unit, for one, across a bending wire or strip and, for another, across a pin forming a break-away connection between the retaining part and the jacket unit. If, in the event of a crash, a force, acting onto the steering wheel-side end of the steering shaft parallel to the longitudinal axis of the steering shaft in the direction towards the vehicle front, exceeds a limit value, the pin is shorn off and the break-away connection is consequently released. The jacket unit can then become dislocated with respect to the retaining part parallel to the longitudinal axis of the steering shaft in the direction toward the vehicle front, wherein the bending wire or strip is deformed and thereby energy is absorbed. The retaining part is herein hindered from being displaced in the direction parallel to the longitudinal axis of the steering shaft through its engagement with its securement part of the securement device. In the opened state of the securement device, the securement part is raised from the retaining part and the jacket unit, together with the retaining part, can be displaced parallel to the longitudinal axis of the steering shaft in order to carry out a length positioning of the steering column. Further, in the opened state of the securement device, a height or inclination adjustment of the steering column is feasible.
One disadvantage in this prior known steering column includes that during the opening of the break-away connection a force peak (=break-away peak) occurs, e.g. the limit value of the force acting parallel to the longitudinal axis of the steering shaft, starting at which the break-away connection is released and an energy absorbing displacement of the jacket unit with respect to the retaining part sets in, is relatively high. After the break-away connection has been released, the force counteracting a displacement of the jacket unit with respect to the retaining part is less.
SUMMARY OF THE INVENTION
The invention addresses the problem of at least decreasing this force peak (=break-away peak), and to do so in a simple and cost-effective yet functionally advantageous implementation.
This is attained according to the invention through a steering column with the features described below or, respectively, through a method for the production of a steering column with the features described below. Advantageous further developments are described in the dependent claims.
In the steering column of the invention an elastic prestress is exerted onto the at least one bending wire or strip. The jacket unit is thereby prestressed with respect to the retaining part in the displacement direction parallel to the longitudinal axis of the steering shaft in the direction toward the vehicle front. This prestress acts on the break-away connection between the jacket unit and the retaining part. The force required in the event of a crash to release the break-away connection is thereby decreased since the elastic reset force of the at least one bending wire or strip is added to the force exerted, in particular through the secondary collision of the driver with the steering wheel, parallel to the longitudinal axis of the steering shaft in the direction toward the vehicle front. The force peak during the breaking away of the jacket unit from the retaining part (=break-away peak) can thereby be decreased or entirely avoided. Nevertheless, in normal driving operation (thus when no vehicle crash occurs), an adequately stable connection is provided between the retaining part and the jacket unit, through which a shaking between the jacket unit and the retaining part and vibrations through intrinsic resonances can be avoided, and this can be achieved with a very simple implementation.
The steering column is preferably implemented such that it is adjustable in length. An openable and closable securement device is herein provided, in the opened state of which the jacket unit is displaceable with respect to a bracket unit supporting the jacket unit parallel to the longitudinal axis of the steering shaft and which, in its closed state, applies a securement force for the securement of the jacket unit with respect to the bracket unit against a displacement parallel to the longitudinal axis of the steering shaft. In the mounted state of the steering column the bracket unit is herein firmly secured on the vehicle, at least in normal operation, thus without a crash having occurred, e.g. up to a maximum force acting in the direction of the longitudinal axis of the steering shaft.
An advantageous embodiment of the invention provides that the retaining part is formed by a part of the securement device. The retaining part in the closed state of the securement device is herein in engagement with a securement part which is secured in position with respect to the bracket unit such that it is nondisplaceable in the direction of the longitudinal axis of the steering shaft. Through this engagement between the securement part and the retaining part, at least a portion of the securement force is applied securing, in the closed state of the securement device, the jacket unit against a displacement parallel to the longitudinal axis of the steering shaft. In the opened state of the securement device, the retaining part and the securement part are out of engagement. However, the energy absorption device for enabling the energy absorbing dislocation of the jacket unit in the event of a crash is integrated into the securement device. In this embodiment of the invention, the vehicle-stationary mounting of the bracket unit can be provided. A further energy absorbing dislocateability between the bracket unit and a mounting part, displaceably supporting this bracket unit parallel to the longitudinal axis of the steering shaft and mounted stationarily on the vehicle, can consequently be omitted.
Since in this embodiment of the invention the securement part, referred to in the direction of the longitudinal axis of the steering shaft, is nondisplaceable with respect to the bracket unit. The retaining part, during the displacement of the jacket unit with respect to the bracket unit, in the opened state of the securement device moves simultaneously with the jacket unit. The securement part and the retaining part thus come in different length settings of the steering column in different positions into mutual contact when the securement device is closed. In the closed state of the securement device, the displacement of the retaining part with respect to the securement part (in the direction parallel to the longitudinal axis of the steering shaft) is counteracted by securement elements cooperating, preferably under form closure, advantageously through cooperating toothings. The securement of the jacket unit in the closed state of the securement device against a displacement in the length displacement direction, consequently, takes place at least also via the cooperation of the securement part with the retaining part. Additionally, for example, securement elements acting under frictional closure can be provided for the securement of the jacket unit against a displacement in the length displacement direction in the closed state of the securement device.
The height or inclination of the steering column is especially preferably also settable in the opened state of the securement device.
In the event of a crash, after the break-away connection has been released during the dislocation of the jacket unit with respect to the retaining part (which is held nondisplaceably with respect to the securement unit in the direction parallel to the longitudinal axis of the steering shaft), at least a section of the at least one bending wire or strip is entrained by the jacket unit. The deformation of the bending wire or strip takes place by the bending of the bending wire or strip or comprises at least one such. The bending wire or strip preferably comprises two legs connected via a recurvature, wherein the two legs form an angle in particular in the range of 150° to 220°, preferably an angle of 180°, such that a U-shaped development of the bending wire or strip results.
An advantageous development provides that the bending wire or strip is at least partially enclosed in a housing which preferably is formed by a portion of the jacket unit. For this purpose, a rail U-shaped in cross section is secured in position on a jacket tube rotatably supporting the steering shaft. A development of the housing or a portion thereof on the, respectively of the, bracket unit is also conceivable and feasible.
The break-away connection between the retaining part and the jacket unit can be formed, for example, by a pin connecting these two parts, which, in the event of a crash, is sheared off if the limit value of the force acting upon the steering shaft and thereover onto the jacket unit parallel to the longitudinal axis of the steering shaft in the direction toward the vehicle front is exceeded. Other types of form closure connections, which, in the event of a crash, are released through material reforming, material shearing or fracture, are also conceivable and feasible. A break-away connection can, for example, also be attained through a frictional closure connection which, if the limit value of the force is exceeded, enables a dislocation of the jacket unit with respect to the retaining part and only acts over a small first segment of the displacement path. Consequently, as a break-away connection any connection between the jacket unit and the retaining part should be considered which, after a displacement over a short displacement path between the jacket and the retaining part (parallel to the longitudinal axis), which is preferably less than two centimeters, counteracts a further displacement between the jacket unit and the retaining part with no force or only a significantly lower than initial force, preferably less than one tenth of the initial force.
Accordingly, a solder connection or welded connection or adhesive connection is suitable as the break-away connection if it is laid out such that it is released when the desired force is exceeded.
BRIEF DESCRIPTION OF THE DRAWINGS
Further advantages and details of the invention will be explained in the following in conjunction with the enclosed drawings, in which:
FIG. 1 is a side view of a steering column according to a first embodiment of the invention;
FIG. 2 is a section view along line BB of FIG. 1 ;
FIG. 3 is a section view along line AA of FIG. 1 ;
FIG. 4 is an oblique view of the steering column of FIG. 1 ;
FIG. 5 is an oblique view of the jacket unit, of the section of the steering shaft rotatably supported thereby and the retaining part;
FIG. 6 is a section view corresponding to line CC of FIG. 2 , wherein, however, are omitted the bracket unit, the intermediate unit and the securement device, apart from the securement part in engagement with the retaining part (shown in section);
FIG. 7 a is a section view along line EE of FIG. 2 during the assembly of the steering column, the parts listed in FIG. 6 being again omitted;
FIG. 7 b is a section view analogous to FIG. 7 a in the completed state of the steering column;
FIG. 8 is a section view analogous to FIGS. 7 a and 7 b after a vehicle crash;
FIG. 9 is an exploded view depicting the jacket unit, of the retaining part and the connection parts connecting these according to a second embodiment of the invention;
FIG. 10 is an oblique view onto the back side, not visible in FIG. 9 , of the retaining part;
FIG. 11 a is a view onto the back side, not visible in FIG. 9 , of the rail of the jacket unit attached on the jacket tube in the state connected with the retaining part, in a state during the assembly of the steering column;
FIG. 11 b is a view corresponding to FIG. 11 a after a further assembly step;
FIG. 11 c is a view corresponding to FIG. 11 a in the completed state of the steering column.
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the invention is depicted in FIGS. 1 to 8 . The steering column comprises a jacket unit 2 which bearing supports a steering shaft 1 rotatably about the longitudinal axis 4 of the steering shaft 1 , which comprises a steering wheel-side end 3 serving for the connection of a steering wheel, not shown in the Figures. The jacket unit 2 is connected with a retaining part 5 across a break-away connection and energy absorption connection, which will be more precisely described later. Up to a limit value of a force acting between the jacket unit and the retaining part 5 parallel to the longitudinal axis 4 , the retaining part 5 is connected with the jacket unit 2 such that it is nondisplaceable relative to the direction of the longitudinal axis 4 . The limit value can herein be identical or different for the two directions parallel to the longitudinal axis 4 and be set during the construction of the system.
A force F (or the corresponding force component parallel to the longitudinal axis 4 ), exerted in the event of a crash through the secondary collision of the driver onto the jacket unit 2 , is directed toward the vehicle front, as is illustrated in FIG. 1 , and accordingly is absorbed through a counter-force on the bracket unit 6 .
A bracket unit 6 supporting the jacket unit 2 in the operating state of the steering column is rigidly connected with the chassis of the motor vehicle. In the opened state of a securement device 7 the steering column can be adjusted in length and in height or inclination. The jacket unit 2 is herein displaceable with respect to the bracket unit 6 parallel to the longitudinal axis 4 (=length adjustment direction 8 ) and into a height or inclination adjustment direction 9 , at right angles thereto, with respect to the bracket unit 6 . In the closed state of the securement device 7 a securement force, for the securement of the jacket unit 2 relative to a displacement taking place parallel to the longitudinal axis 4 with respect to the bracket unit 6 , is applied, wherein the securement force is, at least relative to a displacement parallel to the longitudinal axis 4 in the direction toward the vehicle front, higher than the limit value of the force up to which the jacket unit 2 is held nondisplaceably with respect to the retaining part 5 . Further, by the securement device 7 , a securement force for the securement of the jacket unit 2 is applied against a displacement with respect to the bracket unit 6 in the height or inclination adjustment direction 9 .
In the depicted embodiment, the jacket unit 2 is located between side jaws 10 , 11 of the bracket unit 6 . Between the side jaws 10 , 11 of the bracket unit 6 and the jacket unit 2 are located side flanks 12 , 13 of an intermediate unit 14 which encompasses the jacket unit 2 at least over a large portion of its circumference. In the opened state of the securement device 7 the intermediate unit 14 is displaceable with respect to the bracket unit 6 in the height or inclination adjustment direction 9 . For this purpose, it is swivellable about a swivel axis 15 with respect to the bracket unit 6 . The intermediate unit 14 is connected with the bracket unit 6 nondisplaceably, relative to the direction of the longitudinal axis 4 , for example (also) via the development of this swivel axis 15 . The jacket unit 2 in the opened state of the securement device 7 is displaceable with respect to the intermediate unit 14 , displaceably guiding the jacket unit 2 , parallel to the longitudinal axis 4 and, in the closed state of the securement device 7 , is held nondisplaceably with respect to the intermediate unit 14 through the securement force applied by the securement device 7 in the direction of the longitudinal axis 4 .
The securement device 7 comprises a clamp bolt 16 extending at right angles to the longitudinal axis 4 which penetrates through openings 17 , 18 (cf. FIG. 2 ) in the side jaws 10 , 11 , which are implemented as elongated holes extending in the direction of the height or inclination adjustment 9 and in which the clamp bolt 16 shifts during the height or inclination adjustment of the steering column. The clamp bolt 16 is held by the margins of these openings 17 , 18 nondisplaceably, relative to the direction of the longitudinal axis 4 , with respect to the bracket unit 6 . The clamp bolt 16 , further, penetrates openings in the side flanks 12 , 13 of the intermediate unit 11 whose diameter, apart from a sliding clearance, correspond to that of the clamp bolt 16 .
On the clamp bolt 16 securement parts 19 , 20 are disposed on both sides of the side jaws 10 , 11 of bracket unit 6 , through which parts penetrates the clamp bolt 16 through openings and which are axially displaceable in the direction of the axis of the clamp bolt 16 . The one securement part 19 includes a section in which it is penetrated by clamp bolt 16 and a section 22 connected therewith across a connection section 21 , in which section 22 the part 19 cooperates, as will be described below, with the retaining part 5 . The securement part 20 and the securement part 19 , in the proximity of its section penetrated by clamp bolt 16 , in the closed state of the securement device are pressed onto the side jaws 10 , 11 of the bracket unit 6 in order to secure in position the adjustment of the steering column in the height or inclination adjustment direction. This securement in position can take place through frictional closure. Elements cooperating under form closure, for example toothings, can also be provided.
For tightening the securement parts 19 , 20 with the side jaws 10 , 11 and securement part 19 with the retaining part 5 , the securement device 7 can be implemented in the conventional manner. For example, a clamping lever 23 serving for opening and closing the securement device 7 is connected with a cam disk 24 , which it entrains upon a turning about the axis of the clamp bolt 16 and which cooperates with a link disk. The link disk is here implemented as integral with the securement part 19 , but a separate link disk could also be provided. Configurations with rolling bodies or other implementations of clamping mechanisms are also applicable.
The section 22 of the securement part 19 penetrates an opening in the side jaw 10 (the side jaw 10 could also terminate above the section 22 of the securement part 19 ) and an opening in side flank 12 of the intermediate unit 14 . In the closed state of the securement device, section 22 is pressed with a toothing 25 disposed thereon onto a toothing 26 of the retaining part 5 . Depending on the length positioning of the steering column, the toothings 25 , 26 come into mutual contact in different positions.
Section 22 of securement part 19 , which in its entirety is located on one side of clamp bolt 16 , is held nondisplaceably against a shift with respect to the bracket unit 6 in a direction parallel to the longitudinal axis 4 by the margins of the penetrated opening in side jaw 10 and/or by the margins of the penetrated opening in side flank 12 of the intermediate unit 14 .
Through the cooperating toothings 25 , 26 the retaining part 5 in the closed state of the securement device 7 is secured in position against a displacement with respect to securement part 19 in the direction of the longitudinal axis 4 . If, during the closing of the securement device 7 , these two toothings come into mutual contact in a tooth-on-tooth position, at least after a minimal initial shift (which is less than the tooth spacing of the toothing) a further shifting of the retaining part 5 with respect to the securement part 19 is blocked.
Other form-closure connections between the securement part 19 and the retaining part 5 are also feasible, for example via bolts engaging into holes.
In the opened state of the securement device 7 the securement part 19 is retracted from the retaining part 5 and these two parts are brought out of engagement, wherein the jacket unit 2 , together with the retaining part 5 , is displaceable in the length adjustment direction 8 .
Apart from the type of implementation of the connection between the jacket unit 2 and the retaining part 5 , which will be described more precisely in the following, the elements of the steering column described above can be implemented in a manner known from prior art, in particular according to DE 10 2008 034 807 B3 cited in the introduction to the description.
The retaining part 5 is guided displaceably with respect to the jacket unit 2 parallel to the longitudinal axis 4 and is connected with the jacket unit 2 , for one, across a break-away connection and, for another, across an energy absorption connection. The break-away connection can be realized, for example, via a shear bolt 27 . In the depicted embodiment example, the shear bolt 27 is set, on the one hand, into an opening 28 in the retaining part 5 , for example into an opening 29 (cf. FIG. 3 ). The jacket unit 2 comprises in this embodiment example a jacket tube 30 and a rail 31 with U-shaped cross section rigidly connected therewith, for example by welding, and extending in the direction of the longitudinal axis 4 . The opening 29 is here implemented in the rail 31 .
For developing the energy absorption connection serves a bending wire or strip 32 , which is connected, on the one hand, with the retaining part 5 , on the other hand, with the jacket unit 2 . In the depicted embodiment, the bending wire or strip 32 is developed in the shape of a U, wherein the one U-leg is connected with the retaining part 5 and the other U-leg with the jacket unit 2 , specifically with the rail 31 . The connections of the U-legs are each such that they act in both directions parallel to the longitudinal axis 4 , preferably under form closure. The two U-legs preferably extend, at least substantially, parallel to the longitudinal axis 4 .
To connect the one U-leg with the retaining part 5 , this part can comprise, for example, a pin 33 projecting through a slot 34 extending parallel to the longitudinal axis 4 in the rail 31 and engaging into an eyelet 35 in the bending wire or strip 32 . The connection of the other U-leg with the jacket unit 2 can be developed, for example, by placing the end of the U-leg in contact on a stop 36 of the rail and through extensions 37 of the rail engaging into indentations in the U-leg.
In the embodiment, the bending wire or strip 32 is enclosed in an inner chamber of a housing formed by the rail 31 and the section of the jacket tube 30 terminating it. In this housing, the bending of the bending wire or strip 32 takes place freely, thus not about a pin.
During assembly of the steering column, the bending wire or strip is elastically deformed, e.g. it is deformed with respect to a neutral position which it assumes without external forces, wherein it exerts a reset force in the direction of the neutral position. For this purpose the bending wire or strip 32 is comprised of an adequately elastic material, for example a spring-elastic steel. Through this elastic prestress of the bending wire or strip 32 , the jacket unit 2 is prestressed with respect to the retaining part 5 relative to a displacement parallel to the longitudinal axis 4 in the direction toward the motor vehicle front.
The implementation of this prestress is depicted schematically in FIGS. 7 a and 7 b . In FIG. 7 a , the bending wire or strip has its non-prestressed neutral position which it assumes without action of an external force, wherein it is connected with the jacket unit 2 and the retaining part 5 . As indicated in FIG. 7 a , in this production step the opening 28 in the retaining part 5 (shown above the longitudinal axis 4 ) and the opening 29 in rail 31 (shown beneath the longitudinal axis 4 ) are offset with respect to one another in the direction of the longitudinal axis 4 .
The retaining part 5 is subsequently displaced (toward the left in FIG. 7 b ) with respect to the jacket unit 2 parallel to the longitudinal axis 4 by a distance d in the direction toward the vehicle front, wherein the pin 33 elastically prestresses the bending wire or strip. In this prestressed position according to FIG. 7 b , the opening 28 in the retaining part 5 (shown above the longitudinal axis 4 ) and the opening 29 in the rail 31 (shown beneath the longitudinal axis 4 ) overlap one another and the shear bolt 27 is now inserted (illustrated by the arrow in FIG. 7 b ) whereby the break-way connection is implemented.
If in the event of a crash at least a force acting parallel to the longitudinal axis 4 in the direction toward the vehicle front is exerted onto the steering wheel-side end 3 of the steering shaft 1 , in particular through the secondary collision of the driver, this force is transmitted from the steering shaft 1 onto the jacket unit 2 and is added to the prestress force exerted by bending wire or strip 32 , and, if the sum of these forces exceeds a limit value, the break-away connection is released through the shearing-off or breaking-off of the shear bolt 27 . Therewith, the dislocation of the jacket unit 2 parallel to the longitudinal axis 4 in the direction toward the vehicle front can commence, thus into the direction away from the steering wheel-side end 3 of the steering shaft 1 , wherein the jacket unit 2 is dislocated with respect to the retaining part firmly secured by the securement part 19 . After a first partial segment of this displacement path, which is preferably smaller than one tenth of the entire displacement path between the jacket unit 2 and the retaining part 5 , the bending wire or strip 32 starts to counteract the further dislocation with a force as soon as the neutral position of the bending wire or strip 32 has been reached or has been exceeded. During the further dislocation, the bending wire or strip 32 is deformed with the absorption of energy, wherein this deformation, after a further segment of the displacement path which is preferably smaller than a tenth of the entire displacement path, transitions into a plastic deformation. The state after the vehicle crash in shown in FIG. 8 .
For the layout of the energy absorption, in particular with respect to magnitude and course, the cross section and the cross section course of the bending strip 32 can be dimensioned appropriately. Further, essential for the energy absorption behavior are the strength of the connection between the rail 31 with the jacket unit 2 and the metal sheet thickness of the rail 31 as well as the course of the width of the slot 34 in the rail 31 . Additionally, the radius of curvature of the rail 31 in the direction of the tabs, with which the rail 31 is secured on the jacket unit 2 , is a parameter affecting the determination of the energy absorption behavior.
The securement device can hold the jacket unit 2 , even additionally to the mounting through the engagement between the securement part 19 and the retaining part 5 , for example under frictional closure, against a displacement parallel to the longitudinal axis 4 , for example, so that during the closing of the securement device 7 , the intermediate unit 14 is tightened against the jacket unit 2 . Such an additional holding force exerted by the securement device 7 directly onto the jacket unit 2 is taken into account in the limit value of that force above which, in the event of a crash, a dislocation of the jacket unit 2 with respect to the bracket unit 6 occurs.
A second embodiment form of the invention is depicted in FIGS. 9 to 11 . The distinction from the previously described embodiment lies in the energy absorption connection between the jacket unit 2 and the retaining part 5 . The break-away connection is implemented by a shear bolt 27 as in the previously described embodiments.
The one U-leg of the bending wire or strip 32 is secured with the rail 31 against a displacement in both directions parallel to the longitudinal axis 4 through prominences 38 of the bending wire or strip 32 , which engage into a cutout 39 of the rail 31 . However, only one prominence 38 engaging into a cutout 39 could also be provided. The other U-leg includes at the end side a bend-off with a thickened end 40 . This is retained in an interspace between projections 41 , 42 disposed on the retaining part 5 , which penetrate the slot 34 in the rail 31 . This leg of the bending wire or strip is thereby held nondisplaceably in both directions of the longitudinal axis 4 with respect to the retaining part 5 .
During the assembly, the unstressed bending wire or strip 32 is inserted and connected with both of its legs with the retaining part 5 and the rail 31 . The retaining part 5 is subsequently first displaced parallel to the longitudinal axis 4 by a distance c in the direction away from the vehicle front, thus in the direction toward the steering wheel-side end 3 of the steering shaft 1 (toward the left in FIG. 11 b ), see the position evident in FIG. 11 b in comparison to FIG. 11 a . During this displacement, a plastic deformation of the bending wire or strip 32 occurs. Manufacturing tolerances can thereby be compensated such that in this manner a defined starting state is attained. Subsequently, there results a displacement of the retaining part 5 by a distance d parallel to the longitudinal axis 4 in the direction toward the vehicle front, thus away from the steering wheel-side end 3 of the steering shaft 1 (toward the right in FIG. 11 c ), wherein the bending wire or strip 32 is elastically prestressed, see FIG. 11 c in comparison to FIG. 11 b . In this position, the openings 28 , 29 in the retaining part 5 and in the rail 31 overlap and the shear bolt 27 is inserted, which is illustrated by the arrow in FIG. 11 c.
The described plastic deformation before the elastic prestress could also be carried out in the case of the first described embodiment.
In addition to the already listed advantages, the solution according to the invention has an advantageous effect on the noise behavior of the steering column. Through the prestress a dampening effect is achieved.
The break-away connection between the retaining part 5 and the jacket unit 2 could also be implemented in a manner other than in the first and second embodiment, e.g., a nose tapering the slot 34 could also be provided, over which the pin 33 or the projection 41 would need to drive for the release of the break-away connection. The break-away connection secures the jacket unit 2 with respect to the retaining part 5 and in normal operation thus prevents shaking of the jacket unit 4 with respect to the retaining part 5 .
An implementation with more than one bending wire or strip 32 is also conceivable and feasible. One of the bending wires or strips or more than one of the bending wires or strips could here be elastically prestressed in the described manner. For example, on both sides of the jacket unit 2 retaining parts 5 could be provided which cooperate with securement parts, for example in the manner described in connection with the securement part 19 . Both retaining parts 5 could herein be connected with the jacket unit 5 across an energy absorption connection comprising at least one bending wire or strip 32 and across a break-away connection. A connection of only one of the retaining parts with the jacket unit through an energy absorption connection or through a break-away connection is also feasible.
Although the implementation with side jaws 10 , 11 of the bracket unit 6 disposed on both sides of the jacket unit 2 is preferred, against which, in the closed state of the securement device 7 , parts of the securement device are tightened, implementations are also conceivable and feasible in which the bracket unit comprises only one side jaw located on one side of the jacket unit 2 .
A steering column according to the invention could, for example, also be implemented such that it is adjustable only in the length adjustment direction 8 . In such an embodiment, the intermediate unit 14 could be omitted and the opening 17 , 18 through which penetrates clamp bolt 16 could be implemented in the shape of a circle in each side jaw 10 , 11 of the bracket unit.
A steering column adjustable in the length adjustment direction 8 as well as also in the height or inclination adjustment direction 9 can also be implemented without an intermediate unit 14 . Herein in the jacket unit 2 elongated holes could be provided, penetrated by clamp bolt 16 , which extend in the length adjustment direction 8 of the steering column. For example, for this purpose on the jacket tube 30 at least one upwardly or downwardly projecting part could be disposed in which these elongated holes are disposed.
The jacket unit 2 can also, at least over a portion of its longitudinal extent, be implemented such that it is circumferentially open.
If, through a frictional closure connection a sufficiently high desired securement force in the direction of the length adjustment 8 between the retaining part 5 and a securement part 19 is attainable, a frictional closure engagement between these two parts could also be provided. To increase the securement force could herein also be provided additional cooperating friction faces, for example in the form of cooperating lamellae. Such cooperating lamellae could also be provided for the additional securement in the height or inclination adjustment direction 9 .
As is known, the bracket unit 6 could also be connected, dislocatably in the direction parallel to the longitudinal axis 4 in the event of a crash under energy absorption, with a mounting part connected stationarily on the vehicle.
For the case that an energy absorption is required in a direction that does not coincide with the longitudinal direction of the steering column (=direction of the longitudinal axis 4 ), the device according to the invention can also be oriented in this direction. The prestress would in that case be introduced in this direction into the one or the several bending wires or strips 32 . According to the illustrated examples, the rail 31 would be accordingly secured on the jacket unit oriented in this direction.
LEGENDS TO THE REFERENCE NUMBERS
1 Steering shaft
2 Jacket unit
3 Steering wheel-side end
4 Longitudinal axis
5 Retaining part
6 Bracket unit
7 Securement device
8 Length adjustment direction
9 Height or inclination adjustment direction
10 Side jaw
11 Side jaw
12 Side flank
13 Side flank
14 Intermediate unit
15 Swivel axis
16 Clamp bolt
17 Opening
18 Opening
19 Securement part
20 Securement part
21 Connection section
22 Section
23 Clamping lever
24 Cam disk
25 Toothing
26 Toothing
27 Shear bolt
28 Opening
29 Opening
30 Jacket tube
31 Rail
32 Bending wire or strip
33 Pin
34 Slot
35 Eyelet
36 Stop
37 Extension
38 Prominence
39 Cutout
40 End
41 Projection
42 Projection | 4y
|
BACKGROUND
[0001] This disclosure relates generally to a flow control device and, more particularly, to a turbomachine flow control device having a reduced signature.
[0002] Some turbomachines include modulated exhaust flow control devices, especially turbomachines incorporating augmentors. The modulated exhaust flow control devices move between positions that force more air through exhaust cooling passages and positions that force less air through the exhaust cooling passages. Forcing more air through the exhaust cooling passages complicates the path the air must travel before being exhausted from the turbomachine. Reducing the air moving through the exhaust cooling passages can increase thrust, fuel efficiency, or both. More air is typically forced through the exhaust cooling passages when the turbomachine is operating in an augmented mode.
[0003] Tied liners are an example of exhaust cooling passages. The modulated exhaust flow control devices are a type of flow control device. Radar detection devices may detect these modulated exhaust flow control devices.
SUMMARY
[0004] A flow control device assembly for a turbomachine according to an exemplary embodiment of the present disclosure includes, among other things, a flow control device configured to move between a first position and a second position. The flow control device in the first position forces more flow through a plurality of cooling holes than the flow control device in the second position. The plurality of cooling holes are upstream the flow control device relative to a direction of flow through the turbomachine.
[0005] In a further non-limiting embodiment of the foregoing flow control device assembly, the flow control device in the first position may block more flow through an exit of a bypass flow path than the flow control device in the second position.
[0006] In a further non-limiting embodiment of either of foregoing flow control device assemblies, the flow control device may be positioned axially closer to an aft end of an exhaust duct than a forward end of the exhaust duct.
[0007] In a further non-limiting embodiment of any of foregoing flow control device assemblies, the flow control device may be positioned radially between the exhaust duct and an outer case of the turbomachine when moving between the first and second positions.
[0008] In a further non-limiting embodiment of any of foregoing flow control device assemblies, the plurality of cooling holes may be in a exhaust duct, and the plurality of cooling holes may all be upstream the flow control device relative to a direction of flow through the turbomachine.
[0009] In a further non-limiting embodiment of any of foregoing flow control device assemblies, the flow control device may be axially spaced from a turbine exhaust case of the turbomachine.
[0010] In a further non-limiting embodiment of any of foregoing flow control device assemblies, the flow control device may be axially spaced from an axially rearmost vane of an exhaust section of the turbomachine.
[0011] In a further non-limiting embodiment of any of foregoing flow control device assemblies, the flow control device may be moveable to positions between the first position and the second position.
[0012] A turbomachine assembly according to another exemplary embodiment of the present disclosure includes, among other things, an exhaust duct extending axially from an exhaust section of a turbomachine. The exhaust duct has a plurality of cooling holes. A flow control device is at an aft end of the exhaust duct. The flow control device is configured to move between a first position and a second position. The flow control device in the first position causes more air to move through the cooling holes than the flow control device in the second position.
[0013] In a further non-limiting embodiment of the foregoing turbomachine assembly, the flow control device may be spaced from an axially rearmost vane of an exhaust section of the turbomachine.
[0014] In a further non-limiting embodiment of either of the foregoing turbomachine assemblies, the flow control device is positioned radially between the exhaust duct and an outer case of the turbomachine.
[0015] In a further non-limiting embodiment of any of the foregoing turbomachine assemblies, the plurality of cooling holes are all upstream the flow control device relative to a direction of flow through the turbomachine.
[0016] In a further non-limiting embodiment of any of the foregoing turbomachine assemblies, the flow control device is axially spaced from a turbine exhaust case of the turbomachine.
[0017] A method of selectively directing flow through cooling holes of a tied exhaust duct according to another aspect of the present disclosure includes moving a flow control device from a first position to a second position to direct more flow through cooling holes of an exhaust duct. The cooling holes are upstream the flow control device.
[0018] In a further non-limiting embodiment of the foregoing method of selectively directing flow through cooling holes, the method may move the flow control device from the first position to the second position to block flow.
[0019] In a further non-limiting embodiment of either of the foregoing methods of selectively directing flow through cooling holes, the flow control device may be located within an aftmost portion of a bypass flowpath of a turbomachine having the exhaust duct.
DESCRIPTION OF THE FIGURES
[0020] The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures that accompany the detailed description can be briefly described as follows:
[0021] FIG. 1 shows a section view of an example turbomachine.
[0022] FIG. 2 shows an aft end view of the turbomachine of FIG. 1 .
[0023] FIG. 3 shows a close up view of a portion of the turbomachine of FIG. 2 .
[0024] FIG. 4A shows a schematic section view of an example flow control device in a first position.
[0025] FIG. 4B shows a schematic section view of an example flow control device in a second position.
DETAILED DESCRIPTION
[0026] Referring to FIGS. 1 to 3 , a gas turbine engine 10 is an example type of turbomachine. The engine 10 includes a fan section 12 , a compressor section 14 , a combustor section 16 , a turbine section 18 , a turbine exhaust case 20 , and an exhaust nozzle section 22 . The compressor section 14 , combustor section 16 , and turbine section 18 are generally referred to as the core engine. The turbine exhaust case 20 forms a portion of an augmentor for the engine 10 . An axis A extends longitudinally through the engine 10 .
[0027] Although depicted as a two-spool gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with such two-spool designs. That is, the teachings may be applied to other types of turbomachines and gas turbine engines, including three-spool architectures.
[0028] In some examples, the engine 10 may incorporate a geared architecture 24 that allows a fan of the fan section 12 to rotate at a slower speed than a turbine that is driving the fan. The geared architecture 24 may include an epicyclic geartrain, such as a planetary geartrain, or some other gear system.
[0029] In the example engine 10 , flow moves from the fan section 12 to a bypass flowpath B. Flow from the bypass flowpath B through the exhaust nozzle section 22 generates forward thrust. The compressor section 14 drives flow along a core flowpath. Compressed air from the compressor section 14 communicates through the combustor section 16 . The products of combustion expand through the turbine section 18 .
[0030] The turbine exhaust case 20 of the example engine 10 includes an inner case 26 , an outer case 30 , and an annular array of vanes 34 extending radially therebetween. The vanes 34 are the axially rearmost vanes 34 in the turbine exhaust case 20 . The vanes 34 are film cooled in this example using cooling air that has moved radially through the vanes 34 from the inner case 26 , which comprises a cooled tailcone in this example.
[0031] The vanes 34 each house a fuel spraybar and flameholders. These devices also form portions of the augmentor for the engine 10 . The spraybar supports a plurality of fuel injector assemblies at varied radial positions. When the augmentor is on, fuel sprays into the turbine exhaust case 20 from the fuel injector assemblies. The fuel is ignited to provide additional thrust to the engine 10 as flow from the core engine mixes with the bypass flow B in the exhaust nozzle section 22 and is exhausted from the engine 10 .
[0032] The turbine exhaust case 20 includes an exhaust duct, which, in this example, is a tied liner 38 . In this example, the tied liner 38 extends axially from a position aligned with the vanes 34 to an aft end portion 40 . The tied liner 38 includes a plurality of apertures 42 . Fluid, such as air, from the bypass flow path B is selectively moved through the plurality of apertures 42 to cool the tied liner 38 .
[0033] In this example, portions of the engine 10 downstream from the tied liner 38 are considered the nozzle section 22 , which may include convergent flaps that move to direct flow from the engine.
[0034] In this example, a flow control device 46 is moved between a first position ( FIG. 4A ) and a second position ( FIG. 4B ) to alter the amount of air that is moved through the tied liner 38 before entering the exhaust nozzle section 22 .
[0035] The flow control device 46 , in this example, is positioned radially between the aft end portion 40 of the tied liner 38 and an outer casing 58 of the engine 10 . The flow control device 46 , in this example, is positioned axially at an exit 50 of the bypass flow path B of the engine 10 . Flow that moves through the exit 50 mixes with flow from the core engine within the exhaust nozzle section 22 .
[0036] Although shown positioned at the exit 50 , the example flow control device 46 could be located at other axial positions. For example, the flow control device 46 could be further forward, with some of the plurality of apertures 42 both upstream and downstream from the flow control device 46 . In such axial positions, the flow control device 46 is axially spaced from the vanes 34 and a turbine exhaust case of the engine 10 .
[0037] The flow control device 46 in the first position blocks more flow through the exit 50 than the flow control device 46 in the second position. In one example, the flow control device 46 permits no flow through the exit 50 when the flow control device 46 is in the second position. In other examples, the flow control device 46 permits some flow through the exit 50 when the flow control device 46 is in the second position.
[0038] Permitting more flow through the exit 50 causes less flow to move through the plurality of apertures 42 . Permitting less flow through the exit 50 causes more flow to move through the plurality of apertures 42 , which increases cooling of the tied liner 38 . When the engine 10 is operating in augmented mode, the flow control device 46 is moved to a first position so that more flow is moved through the plurality of apertures 42 and cooling is enhanced.
[0039] A controller 64 is operably coupled to the flow control device 46 in this example. The controller 64 is configured to automatically move the flow control device 46 between open and closed positions depending on cooling requirements of the tied liner 38 , switching to an augmented flight mode, etc. The controller 64 is operated by a pilot in another example.
[0040] Many types of flow control devices could be used to selectively block flow through the exit 50 of the flow path 54 . For example, the flow control device 46 could be an inflatable variable area device. The flow control device 46 could also be an arrangement of mechanical devices, such as a flap, that are pivotable back and forth across the flow path 54 . In another example, the flow control device 46 includes a set of vanes. Some of the vanes are stationary and others circumferentially movable. The vanes are aligned to create openings for flow, or misaligned to block flow. In yet another example, the flow control device 46 is a series of vanes that pivot about their axes to open and close. In yet another example, the flow control device 46 translates axially to open a passage for flow or to close the passage.
[0041] Features of the disclosed examples include a flow control device that is located at a relatively downstream location. This location facilitates reduced signatures as the location is more shielded from a radar emitting device. This location also may facilitate thrust recovery.
[0042] The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. Thus, the scope of legal protection given to this disclosure can only be determined by studying the following claims. | 4y
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The present application is a continuation in part of U.S. Ser. No. 08/640, 664, filed May 1, 1996, U.S. Pat. No. 5,800,900, naming Lawrence E. Mitchell as inventor.
FIELD OF THE INVENTION
This invention generally relates to articles of clothing and footwear, and more particularly to the attachment of decorative patches to articles of clothing and footwear.
BACKGROUND OF THE INVENTION
Ornamental designs and decorative emblems are very popular and commonly found on articles of clothing and footwear, such as sneakers, sandals or shoes. Many people purchase articles of clothing or footwear that have favorite emblems or logos attached to them. Many people, particularly sports fans, tend to purchase many articles of clothing having the decal or logo of their favorite athletic team attached thereto. Teenagers and children, in particular, tend to purchase multiple articles with differing logos and emblems. Clothing that displays emblems, logos, favorite cartoons, sports teams, NASCAR racers or schools is in fashion. The accumulation of clothing and footwear with favorite logos and decals attached thereto becomes prohibitively expensive and space-consuming. The expenses for the clothing become astronomical and therefore limit the amount of articles which may be purchased.
If an individual desires to have differing emblems on different articles of clothing and footwear, the individual must purchase a variety of clothing and footwear at considerable expense. Therefore, there is a need for a interchangeable decorative patch or emblem for an article of clothing or footwear which is inexpensive, convenient, and aesthetically pleasing. The present invention enables an individual to interchange his/her favorite decals with different articles of clothing and footwear. The wearer is able to show enthusiasm for a favorite sports team with logos that are easily applied and removed, enabling one to change the appearance of the clothing or footwear as desired.
SUMMARY OF THE INVENTION
The present invention is an apparatus for attaching a decorative patch or emblem to an article of clothing or footwear comprising a pocket on the article including a backing layer and a surface layer overlaying the backing layer, the surface layer having an opening overlapping the backing layer to form a peripheral pocket therebetween; and a decorative patch having a periphery larger than the opening.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of the apparatus according to the present invention;
FIG. 2 is an enlarged view of FIG. 1 taken along Lines 4--4;
FIG. 3 illustrates a patch;
FIG. 4 is an enlarged view of FIG. 1 showing the patch inserted in the pocket;
FIG. 5 is a cross sectional view of the patch and the pocket;
FIG. 6 is a cross sectional view of the patch inserted within the pocket of the article;
FIG. 7 is an alternative embodiment;
FIG. 8 is another alternative embodiment;
FIG. 9 is a further alternative embodiment;
FIG. 10 is a further alternative embodiment;
FIG. 11 is a further alternative embodiment;
FIG. 12 is a further alternative embodiment showing the strip of material;
FIG. 13 is a further alternative embodiment;
FIG. 14 is a further alternative embodiment;
FIG. 15 is an alternative embodiment;
FIG. 16 is a further alternative embodiment;
FIG. 17 is a further alternative embodiment;
FIG. 18 is a further embodiment; and
FIG. 19 is a further embodiment.
DETAILED DESCRIPTION OF THE INVENTION
For illustrative purposes only, the present invention will be described in detail with regard to a decorative patch for footwear, specifically a sneaker. As shown in FIGS. 1, 2 and 5, the apparatus 10 for attaching a decorative patch 12 to an article of clothing or footwear 14 comprises a pocket 16 on the article 14 which includes a backing layer 18 and a surface layer 20 overlaying the backing layer 18. The surface layer 20 has an opening 22 overlapping the backing layer 18 to form a peripheral pocket 24 therebetween. Preferably, the decorative patch 12 has a periphery larger than the opening 22 and is slightly larger than the pocket 16 to form a snug fit. The decorative patch or emblem 12 has a first releasable attachment 26 on the patch 12. A cooperating releasable attachment 28 is affixed on the pocket 16 for securing the patch 12 in the pocket 16. The first releasable attachment 26 is allocated to the backing layer 18 while a cooperating releasable attachment 28 is on the patch or emblem 12. The backing layer 18 also comprises a releasable attachment 26. Preferably, the releasable attachment 26, 28 comprises hook fasteners and loop fasteners, commonly referred to by its trademark Velcro. However, the releasable attachments 26, 28 may comprise snaps, closures, magnets or other appropriate attachment means, as shown in FIGS. 5, 6, 7, and 8.
The surface layer 20 of the article 14 has an opening 22 which overlaps the backing layer 18, providing a sufficient amount of pressure to frictionally hold the patch 12 in the opening 22. As shown in FIGS. 1, 2, and 4, the pocket 16 is preferably created in a non-stress area of the article of clothing or footwear 14. The position of the pocket 16 and opening 22 in such a non-stress area allows the structure of the article 14 of clothing or footwear to be maintained and helps minimize the disturbance of the patch 12. The preferred dimensions of the pocket 16 formed in the article 14 has a depth in the approximate range of 1/8th to 3/16th inch and the overlap dimension of the surface layer 20 is in the approximate range of 1/8th to 1/2 inch.
In an alternative embodiment illustrated in FIG. 9, the peripheral opening 22 may also include an elastic rim 30. The elastic rim 30 is preferably attached to the surface layer 20 and allows a tight fit between the patch 12 and the surface layer 20 while also allowing the flexibility of the overlapping surface layer 20.
The patch 12 may be comprised of the same material as the article 14 it is to be attached to or a different material to promote the distinctiveness of the patch 12 itself. The patch 12 may be comprised of leather, cloth, rubber, elastomer plastic or any suitable material a designer may wish to use. As shown in FIG. 3, the patch 12 may include an illumination means, illuminous material or reflective means 34. Preferably, the patch 12 includes a tab 36 which allows an individual to pull the tab 36 to remove the patch from the pocket 16 in the article 14.
As illustrated in FIG. 10, the releasable attachment 26 may be positioned on the exterior surface of the patch 12 and the interior surface of the surface layer 20 to frictionally hold the patch 12 in the pocket 16, whereby the frictional fit occurs between the exterior of the patch 12 and the overlapping layer of the surface layer 20.
As illustrated in FIG. 11, the releasable attachment 26 may be attached to the surface layer and the exterior surface of the patch. Further, in an alternative embodiment as shown in FIG. 17, the releasable attachment 26 may be attached to the backing layer and surface layer and a cooperating layer of releasable attachment, preferably hook and loop fasteners, may be attached to a section of both sides of the patch. In another embodiment, the releasable attachment may be positioned on at least one surface of the patch, preferably the exterior surface (FIG. 19), and a cooperating layer of releasable attachment may be attached to at least one or both of the backing layer or the surface layer as shown in FIGS. 5, 10, 11, 17, 18 and 19.
Preferably, as shown in FIGS. 18 and 19, cooperating layer 26 (i.e. hook fastener) is located on the surface layer 20 while cooperating layer 28 (i.e. loop fastener) is located on the backing layer. In this preferred mode, cooperating layer 28 (a hook fastener) may interact or engage with cooperating layer 26 (a loop fastener) such that the surface layer 20 and backing layer 18 engage to provide a more compressed or tighter fit around the outer periphery of the patch 12.
In alternative embodiments shown in FIGS. 14 and 15, the patch 12 may include a recess groove 38 in its peripheral surface such that the patch 12 and the surface layer 20 form a tongue and groove frictional fit. That is, a first portion 44 of the peripheral edge of the patch 12 will fit behind the overlapping layer of the surface layer 20 while a second portion 46 of the patch 12 will lay over the overlapping layer of the surface layer 20. The advantage to such a fit would be to securely mount the patch 12 within the opening. The attachment means may be positioned over the entire surface of the back of the patch and the backing layer of the surface layer of the article or may be selectively positioned in the tongue and groove area of the patch 12 and overlapping layer of the surface area 20 as shown in FIG. 16. Alternatively, the surface layer 20 may include a recess groove 48 such that a portion of the patch 12 sits within the recess groove 48, as shown in FIG. 10.
In an additional embodiment shown in FIG. 12, the apparatus 10 further comprises a strip of material 40, having a releasable attachment 26 located on its interior surface and having a cooperating releasable attachment 28 on its exterior surface, fixedly attached to the article 14 at one location along a periphery of the strip of material 40 and removeably attached along a remainder of the periphery. A patch 12 may be removeably positioned between the strip of material 40 and the article 14. The strip of material 40 may include a cover 42, preferably clear, which covers the patch in its desired position.
In a further embodiment shown in FIGS. 13 and 14, the patch 12 may be a hard plastic material which may be popped into the pocket 16 and inserted underneath the overlapping layer of the surface layer 20. The hard plastic material may than be removed by forcibly pressing the hard material at its center point to release the peripheral edge of the hard material from engagement with the article 14.
Further, the patch 12 may comprise a running light or reflective material which can be inserted into the pocket 16 on the article 14 to provide illumination or safety measures for joggers, little children, bicyclists, or anyone with a concern for safety.
Various changes and modifications may be made within the preview of this invention as will be readily apparent to those skilled in the art. Such changes and modifications are within the scope and teaching of this invention as defined by the claims pended thereto. | 4y
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[0001] The present application hereby claims priority under 35 U.S.C. §119 on German patent application number DE 10229113.6 filed Jun. 28, 2002, the entire contents of which are hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] With modem medical diagnostic methods, such as X-ray computed tomography (CT), image data can be obtained from a measured object that has been examined. As a rule, the measured object that has been examined is a patient.
[0003] X-ray computed tomography—designated CT for short below—is a specific X-ray recording method which, in terms of image structure, differs fundamentally from the classical X-ray layer recording method. In the case of CT recordings, transverse slices are obtained, that is to say depictions of body layers which are oriented substantially at right angles to the axis of the body. The tissue-specific physical variable represented in the image is the distribution of the attenuation of X radiation μ(x,y) in the section plane. The CT image is obtained by way of reconstruction of the one-dimensional projections, supplied by the measuring system used, of the two-dimensional distribution of μ(x,y) from numerous different viewing angles.
[0004] The projection data is determined from the intensity I of an X-ray after its path through the layer to be depicted and its original intensity I 0 at the X-ray source in accordance with the absorption law:
ln I I 0 = ∫ L μ ( x , y ) l ( 1 )
[0005] The integration path L represents the path of the X-ray considered through the two-dimensional attenuation distribution μ(x,y). An image projection is then composed of the measured values of the linear integrals through the object layer obtained with the X-rays from one viewing direction.
[0006] The projections originating from an extremely wide range of directions—characterized by the projection angle α—are obtained by way of a combined X-ray detector system, which rotates about the object in the layer plane. The devices which are most common at present are what are known as “fan ray devices”, in which tubes and an array of detectors (a linear arrangement of detectors) in the layer plane rotates jointly about a centre of rotation which is also the centre of the circular measurement field. The “parallel beam devices”, afflicted by very long measuring times, will not be explained here. However, it should be pointed out that transformation from fan to parallel projections and vice versa is possible, so that the present invention, which is to be explained by using a fan beam device, can also be applied without restriction to parallel beam devices.
[0007] In the case of fan beam geometry, a CT recording includes linear integral measured values −1n(I/I 0 ) of incoming beams, which are characterized by a two-dimensional combination of the projection angle αε[0,2π] and the fan angles βε[−β 0 ,β 0 ](β 0 is half the fan opening angle) which define the detector positions. Since the measuring system only has a finite number k of detector elements, and a measurement consists of a finite number y of projections, this combination is discrete and can be represented by a matrix:
{tilde over (p)}(α y ,β k ):[0, 2π)×[−β 0 , β 0 ] (2)
[0008] or
{tilde over (p)}( y,k ):(1, 2, . . . N P )×(1, 2, . . . N S ) (3)
[0009] The matrix {tilde over (p)}(y, k) is called the sinugram for fan beam geometry. The projection number y and the channel number k are of the order of magnitude of 1000.
[0010] If the logarithms are formed in accordance with equation (1), then the linear integrals of all the projections
p ( α ; β ) = ln I I 0 = - ∫ L μ ( x , y ) l ( 2 )
[0011] are therefore obtained, their entirety also being referred to as the radon transform of the distribution μ(x,y). Such a radon transformation is reversible, and accordingly μ(x,y) can be calculated from p(α,β) by back-transformation (inverse radon transformation).
[0012] In the back-transformation, a convolution algorithm is normally used, in which the linear integrals for each projection are firstly convoluted with a specific function and then back-projected onto the image plane along the original beam directions. This specific function, by which the convolution algorithm is substantially characterized, is referred to as a “convolution core”.
[0013] By way of the mathematical configuration of the convolution core, there is the possibility of influencing the image quality specifically during the reconstruction of a CT image from the raw CT data. For example, by way of an appropriate convolution core, high frequencies can be emphasized, in order to increase the local resolution in the image, or by way of a convolution core of an appropriately different nature, high frequencies can be damped in order to reduce the image noise. In summary, therefore, it is possible to state that, during the image reconstruction in computed tomography, by selecting a suitable convolution core, the image characteristic, which is characterized by image sharpness/image contrast and image noise (the two behave in a fashion complementary to each other), can be influenced.
[0014] The principle of image reconstruction in CT by calculating the μ-value distribution will not be discussed further. An extensive description of CT image reconstruction is presented, for example, in “Bildgebende Systeme für die medizinische Diagnostik”[Imaging systems for medical diagnostics], 3rd ed, Munich, Publicis MCD Verlag, 1995, author: Morneburg Heinz, ISBN 3-89578-002-2.
[0015] However, the task of image reconstruction has not yet been completed with the calculation of the revalue distribution of the transilluminated layer. The distribution of the attenuation coefficient It in the medical area of application merely represents an anatomical structure, which still has to be represented in the form of an X-ray image.
[0016] Following a proposal by G. N. Hounsfield, it has become generally usual to transform the values of the linear attenuation coefficient μ (which has the dimensional unit cm −1 ) to a dimensionless scale, in which water is given the value 0 and air the value −1000. The calculation formula for this “CT index” is:
CT index = μ - μ water μ water 1000 ( 4 )
[0017] The unit of the CT index is called the “Hounsfield unit” (HU). This scale, referred to as the “Hounsfield scale”, is very well suited to the representation of anatomical tissue, since the unit HU expresses the deviation in parts per thousand from μ water and the z values of most substances inherent in the body differ only slightly from the μ value of water. From the numerical range (from −1000 for air to about 3000), only whole numbers are used to carry the image information.
[0018] However, the representation of the entire scale range of about 4000 values would by far exceed the discriminating power of the human eye. In addition, it is often only a small extract from the attenuation value range which is of interest to the observer, for example the differentiation between gray and white brain substance, which differ only by about 10 HU.
[0019] For this reason, use is made of what is known as image windowing. In this case, only part of the CT value scale is selected and spread over all the available gray stages. In this way, even small attenuation differences within the selected window become perceptible gray tone differences, while all CT values below the window are represented as black and all CT values above the window are represented as white. The image window can therefore be varied as desired in terms of its central level and also in terms of its width.
[0020] Now, in computed tomography, it is of interest in specific recordings to perform organ-specific settings of the image characteristic and, under certain circumstances, organ-specific windowing. For example, in the case of transverse slices through the breast cavity—in which heart, lungs, spinal column are recorded at the same time—organ-specific optimization of the image representation leads to a far better overview and makes it easier for the user to interpret the CT recording.
[0021] A recording optimized in this way is made, in accordance with the prior art, in that, following recording of the relevant layer, by using different convolution cores during the image reconstruction from the raw data, a series of images is produced which in each case differ from one another in terms of different image characteristics (contrast, noise). The user then decides in which image the respective organ is represented optimally in accordance with the diagnostic requirement. In the selected images, the user must segment—in other words: “mark” and “cut out”—the respective organ and insert it into the final image. For the purpose of segmentation, what are known as segmentation algorithms are available to the user. These generally function in such a way that, within the organ to be segmented, a starting point is set by the user, from which the edge of the organ is determined in accordance with different points of view. The algorithm is moved along the organ boundary until the entire organ has been scanned and therefore cut out and can be inserted into the final image.
[0022] The procedure during segmentation of this type according to the prior art is very time-consuming, since the user has to analyze the entire series of images. Secondly, when cutting out and inserting the segmented organ, no image information must be lost in the transition region (marginal region of the organ), which is not guaranteed in the case of current segmentation algorithms—which additionally (as far as development and computing power are concerned) are extremely complicated.
[0023] Distinguishing organs in a representation can also be carried out by way of a transfer function, which finds and delimits anatomically associated gray value regions in the CT image. This is possible since the attenuation factors in the Hounsfield scale, HU values, as they are known, occupy different regions, depending on the organ. Typically, a transfer function allocates all organ-specific attenuation factors a specific gray value or a specific color. In DE 100 52 540 A1 a diagnostic device is described in which interactive determination of organ-specific gray value regions in a medical image is made possible.
[0024] For this purpose, a histogram is created from the raw data of the medical image and visualized on a user interface. By way of a dialogue interface, the user can then enter values for the determination of an organ-specific gray value region and obtains these values represented as a trapezoidal function in the histogram itself. The values entered thus determine the range of the gray values to be treated and their colored representation in the image, such as color, brightness and hiding power. Values at the edges of the set gray value region are converted with a higher transparency than those in the central region of the selected gray value interval.
[0025] The disadvantage in this case is that adjacent, similar cases exhibit attenuation or gray values in a coherent region of the histogram. The use of the transfer function thus leads to indistinguishability of the two tissues in the image treated.
SUMMARY OF THE INVENTION
[0026] It is therefore an object of an embodiment of the present invention to propose a technique for improving organ-specific image optimization which, in particular, effects optical separation of adjacent tissues of similar consistency in the resulting image.
[0027] An object may achieved in particular by a method according to an embodiment of the invention for organ-specific image optimization in computed tomography, the HU values of a layer of the body previously recorded by a CT device being calculated and, on this basis, a first CT image being created. For this first CT image, a histogram is also created, in which the frequency distribution of the HU values is reproduced. In the histogram, at least one organ-specific HU region is defined and this is allocated an HU-dependent transfer function. Furthermore, a second CT image is created on the basis of the previously calculated HU values for the recorded layer of the body. The first and second CT image are filtered with the HU-dependent transfer function and, finally, the filtered first CT image is mixed with the filtered second CT image.
[0028] Furthermore, an object may be achieved by a computed tomography device which includes a computer for processing measured data and a monitor for visualizing the data processed by the computer, the computer being designed to carry out a method according to an embodiment of the invention.
[0029] Furthermore, an object may be achieved by a computer program product which has a series of physical states which are suitable to be implemented by a computing device which is connected to a computed tomography device in such a way that a method according to an embodiment of the invention is carried out on a computed tomography device.
[0030] Mixing two images indicates that both the characteristics of the first and the characteristics of the second image are expressed in the resulting mixed image, with which, for example, tissue boundaries together with tissue types can be represented.
[0031] An improvement in the result can be achieved if a first image filter is used for creating the first CT image and/or a second image filter is used for creating the second CT image. As an alternative to this, the first CT image can also be created with the aid of a first convolution core, the second CT image also or additionally with a second convolution core. In both methods, the first CT image is advantageously reproduced as a smoothed CT image, the second CT image, if required, as a high-contrast CT image. In this case, the terms first and second CT image relate only to the distinguishability of the two images, not to a certain order, so that the first CT image can also have high contrast, while the second has a smoothed characteristic.
[0032] With regard to good representation of an organ-specific tissue in the resulting image, the magnitude of the HU-dependent transfer function moves in an interval between 0 and 1, it being further possible for the mixing of the first CT image with the second CT image to be carried out expediently as a weighted, pixel by pixel addition of the first CT image to the second CT image. In a preferred embodiment of the present invention, the weighting factor of the first CT image in this case corresponds to the magnitude of the HU-dependent transfer function, and the weighting factor of the second CT image corresponds to the difference between the magnitude of the HU-dependent transfer function and the value 1. In an alternative, likewise preferred embodiment, the weighting factor of the second CT image corresponds to the magnitude of the HU-dependent transfer function, and the weighting factor of the first CT image corresponds to the difference between the magnitude of the HU-dependent transfer function and the value 1.
[0033] Furthermore, in order to create the first and/or second CT image, a two-dimensional, separable image filter can be used. As alternative to this, however, use can also be made of a one-dimensional image filter to create the first and/or the second CT image.
[0034] Simple detection of organ-specific tissue regions in the resulting CT image can be achieved by different, organ-specific HU regions being represented with different windowing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Further features, characteristics and advantages of the present invention will now be explained by using exemplary embodiments and with reference to the accompanying figures of the drawings:
[0036] [0036]FIG. 1 shows schematically a CT apparatus for a fan beam method according to an embodiment of the present invention,
[0037] [0037]FIG. 2 shows a Hounsfield scale in which the Hounsfield units (HE) of different organs in the human body are indicated,
[0038] [0038]FIG. 3 shows windowing in the representation of CT images,
[0039] [0039]FIG. 4 shows a histogram of the HU values in the thorax region,
[0040] [0040]FIG. 5 shows an allocation of different discrete filter functions (transfer functions) to different anatomical tissue,
[0041] [0041]FIG. 6 shows the course of a continuous transfer function by which CT images with a smooth and sharp image characteristic (I sharp and I smooth ) are mixed,
[0042] [0042]FIG. 7 shows how a two-dimensional separable image filter can be replaced by two one-dimensional image filters.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] [0043]FIG. 1 illustrates schematically a computed tomography device for a fan beam method which operates in accordance with an embodiment of the present invention. In this device, X-ray tubes 1 and beam receivers 2 (detectors) rotate jointly about a centre of rotation, which is also the centre of the circular measuring field 5 , and at which the patient 3 to be examined is located on a patient couch 4 . In order to be able to examine different parallel planes of the patient 3 , the patient couch can be displaced along the longitudinal axis of the body.
[0044] As can be seen from the drawing, transverse slices emerge during CT recordings, that is to say depictions of layers of the body which are oriented substantially at right angles to the axis of the body. This layer representation method represents the distribution of the attenuation value μ z (x,y) itself (z is the position on the longitudinal axis of the body). Computed tomography (referred to as CT below) needs projections at very many angles α. In order to produce a layer recording, the radiation cone emitted by the X-ray tube 1 is masked out in such a way that a flat beam fan is produced, which forms one-dimensional central projections of the transilluminated layer.
[0045] For the purpose of exact reconstruction of the distribution of the attenuation values μ z (x,y), this beam fan must be at right angles to the axis of rotation and, in addition, must be spread to such an extent that, from each projection direction a, it completely covers the envisaged layer of the measured object. This beam fan passing through the object is intercepted by detectors which are arranged linearly on a circular segment. In the case of commercially available devices, these are up to 1000 detectors. The individual detector reacts to the incident beams with electrical signals whose amplitude is proportional to the intensity of the beams.
[0046] Each individual detector signal belonging to a projection a is in each case picked up by measuring electronics 7 and forwarded to a computer 8 . Using the computer 8 , the measured data can then be processed in a suitable way and initially visualized on a monitor 6 in the form of a sinugram (in which the projection α is plotted as a function of the measured values from the corresponding channel β) in what are known as Gordon units, but finally in the form of a natural X-ray image in Hounsfield units.
[0047] It is an object of an embodiment of the present invention, by way of a suitable method which is ultimately to be implemented and carried out in the computer 8 , to construct in a simple and rapid way a CT image in which the different anatomical tissue types are represented with different image characteristics (image sharpness and image noise) and thus an organ-specifically optimized CT image is obtained.
[0048] An embodiment of the present invention makes use of the fact that the CT values (HU values) occupy different regions in the Hounsfield scale, depending on the organ.
[0049] The Hounsfield scale is illustrated in FIG. 2. The CT values of the individual organs occupy specific regions, largely irrespective of the X-ray spectrum used. For example, lung tissue and fat, because of their low density and the low attenuation induced by this, exhibit negative CT values in the range from −950 to −550 and −100 to −80, respectively. Most other tissues lie in the positive range (kidneys: 20-40, heart: 40-100, blood: 50-60, liver: 50-70). Bone tissue, because of the high order number of calcium, and therefore the higher attenuation, has CT values up to 2000 HU.
[0050] For conventional CT devices, 4096 (=2 12 ) different gray values are available to represent the entire Hounsfield scale. However, only a maximum of 60 to 80 gray steps can be distinguished by the observer. For this reason, during CT imaging—as already mentioned—windowing is performed, in which the entire gray value scale is allocated to an HU interval of interest. In FIG. 3, this is illustrated by way of example for the region of compact bone substance. The user defines the window interactively by way of its centre (window position C) and width (window width W), for example by way of a mouse or rotary knob. In the example of FIG. 3, the centre is at C=2000, the window width is W=400. In this case, 10 gray steps between white and black are allocated to the window.
[0051] An inventive aspect of an embodiment of the present applicatrion resides in optimizing a CT image in an organ-specific manner on the basis of the CT values in the HU scale and by way of appropriate windowing. According to an embodiment of the invention, it is proposed firstly to represent the CT values (HU values) of the image of a recorded layer in a histogram. A corresponding histogram lists the frequency of the HU values occurring in a CT image as a function of the HU values themselves. Because of the practical restriction of the integer CT and HU values to a closed value range, the representation of the image data in HU values is analogous to a representation of image data in gray values. Therefore, a histogram built up from HU values is frequently also referred to as a gray value histogram in the literature.
[0052] A histogram which is exemplary of the thorax region is illustrated in FIG. 4. Individual HU regions of the histogram (A, B, C, D, E, F) correlate with specific organ structures or, expressed in other words: segment sections (A, B, C, D, E, F) of the HU distribution curve 9 are allocated uniquely to an organ or a tissue structure. In the case of the histogram of FIG. 4, the HU region A, for example, correlates with lung tissue, the region B with fat tissue, C with embedded water, D with blood (e.g. aorta), E with liver tissue and F with heart tissue.
[0053] In order to be able to perform organ-specific setting of the image characteristics (image noise and image sharpness), the respective organ- and tissue-specific HU regions are defined in the histogram. Then, in the simplest case of the embodiment according to the invention, each organ-specific curve section HU(x,y) is assigned its own transfer function λ(HU(x,y)). In this case, HU(x,y) signifies the HU value at the coordinates (x,y) of the CT image whose total frequency is plotted at the corresponding HU value in the histogram. The transfer function λ(HU(x,y)) changes the respective HU value HU(x,y) in such a way that anatomically associated, that is organ- or tissue-specific, image regions are delimited optically from other image regions. λ can therefore be understood as a filter function with which all the image pixels I(x,y) of the respective HU region are filtered. Mathematically, this may be represented as follows:
I (λ( HU ( x,y ))=λ( HU ( x,y )· I ( x,y )
[0054] In the simplest case, λ is a constant function which has a specific value for each organ-specific HU region. For the image representation, this indicates that the tissue-specific HU value regions to be emphasized are each assigned a specific gray value in the image. This specific value has to be defined by the user, taking account of the desired image characteristic of the corresponding organ. In the CT image, this leads to the pixel ranges which belong to corresponding organ-specific gray value zones being filtered or manipulated differently.
[0055] [0055]FIG. 5 represents in simplified form a CT image 10 which has been reconstructed from the raw data and in which the organ-specific gray value zones which belong to the histogram sections from FIG. 4 are circled. As can be seen from the HU region A, the gray value zones do not necessarily have to cohere. In the example of FIGS. 4 and 5, the organ-specific regions A, B, C, D, E, F are filtered on an HU basis.
[0056] This HU-based filtering may be described mathematically as follows:
I (λ 1 )=λ 1 ·I ( HU ( x,y )), HUε A
I (λ 2 )=λ 2 ·I ( HU ( x,y )), HUε B
. . .
I (λ 6 )=λ 6 ·I ( HU ( x,y )), HUε F
[0057] According to an embodiment of the invention, each transfer function a is selected in such a way that the corresponding organ or tissue i appears with the desired optimum image characteristic.
[0058] Following image filtering in accordance with the above procedure, in a further step of an embodiment of the invention, the different HU regions are represented with different windowing. In this case, the average HU value of the structure i of interest is chosen as the centre of the window. The window width depends on the attenuation differences of the respective structure: for the representation of very small attenuation differences, such as in the case of brain tissue, a narrow window is chosen, in the case of large attenuation differences, such as in the case of lung tissue, a wide window is chosen.
[0059] The advantage of the method according to an embodiment of the invention can be seen clearly by using FIG. 5: according to a known method, with regard to the image characteristic, a large number of CT images 10 have to be produced, selected by hand and then, in the selected CT images, the appropriate organ structures have to be segmented and inserted into the final image. In an embodiment of the present invention, the automatically created histogram of the image data provides the relationship between the organ structure i and the associated image elements (pixels: x,y). It is merely necessary for the respective transfer function λ i to be predefined by the user.
[0060] Under certain circumstances, it is desirable to create the histogram only after previously executed manipulation of the reconstructed CT image in the form of image filtering. For example, following smoothing of the CT image, it is possible to represent vessels in the lung parenchyma with the same sharpness as the lung parenchyma itself (a parenchyma is the assembly of cells in an organ which determines its function). If the CT image of a lung recording is sufficiently highly smoothed, then the entire lung, including its vessel structures (not part of the lungs) can be represented in a coherent interval of the histogram. An initial image smoothed in this way will be designated I smooth in the following text. In exactly the same way, however, it may be that, in order to create the histogram, a high-contrast initial image I sharp is required in order, for example, to represent extra-organic tissue with just as high a sharpness.
[0061] The respective HU-based image filtering may be represented as follows in these two cases:
I (λ i )=λ i ·I smooth ( HU ( x,y )), HUε i
[0062] and, respectively,
I (λ i )=λ i ·I sharp ( HU ( x,y )), HUε i
[0063] where i here stands symbolically for the HU value region of the organ structure i.
[0064] In a further embodiment of the invention, the transfer function X, with which the organ-specific histogram regions are filtered, is not discrete but—as illustrated for example in FIG. 6—has a continuous course over the entire histogram region. The course is defined by the user for each layer of the body to be measured. The magnitude of X moves in an interval between 0 and 1. HU-based continuous image filtering of this type may be described mathematically as a mixture of two extreme initial CT images I smooth and I sharp :
I (λ( HU ( x, y ))=λ( HU ( x,y ))· I sharp ( x,y )+(1−λ( HU ( x,y ))) · I smooth ( x,y )
[0065] or else, conversely:
I (λ( HU ( x, y ))=λ( HU ( x,y ))· I smooth ( x,y )+(1−λ( HU ( x,y ))) · I sharp ( x,y )
[0066] The mixture of the two initial images is carried out in this way locally or pixel by pixel by way of the HU-value-dependent transfer function λ(HU(x,y)).
[0067] The production of initial CT images I sharp and I smooth , that is to say of CT images with an extremely sharp or extremely smooth image characteristic, may be implemented in different ways. As early as during the reconstruction of the image from the CT raw data—for example by way of Fourier transformation—it is possible to influence the image characteristic before the back-transformation by way of the selection of an appropriate convolution core (or its Fourier transform). A sharp, edge-emphasizing convolution core supplies a high-contrast initial image I sharp with correspondingly high image noise, while a more gently smoothing convolution core reduces the local resolution but produces a low-noise image I smooth .
[0068] Another possibility is to set the image characteristic caused by a CT convolution core retrospectively from the already reconstructed initial CT image by way of a two-dimensional separable image filter. It is even simpler to replace a two-dimensional separable image filter by two one-dimensional image filters.
[0069] As FIG. 7 illustrates, in the case of a two-dimensional separable image filter with a 1-pixel width, a total of 9 pixels are involved in order to filter one pixel. If the two-dimensional separable image filter according to FIG. 7 is replaced by 2 one-dimensional image filters each having a 1-pixel width, then only three pixels, a total therefore of six pixels, are involved in the filtering for each pixel in each dimension.
[0070] Ultimately, retrospective manipulation of the CT image with 2 one-dimensional image filters firstly signifies a considerable reduction in the computing time. Secondly, filtering of the reconstructed image makes it unnecessary to store the raw data.
[0071] The method and the technique of setting the image characteristic brought about by a CT convolution core by way of a two-dimensional separable image filters or by way of two one-dimensional image filter is presented extensively in T. Flohr, S. Schaller, A. Stadtler et al., “Fast image filters as an alternative to reconstruction kernels in Computed Tomography”, Proceedings of SPIE, vol. 4322 (2001), pp 924-933, the entire contents of which are hereby incorporated herein by reference.
[0072] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. | 4y
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. patent application Ser. No. 11/385,346 filed on Mar. 20, 2006, which is a Continuation of U.S. patent application Ser. No. 10/913,084 filed on Aug. 6, 2004, which is a Divisional of U.S. Pat. No. 6,774,307, filed May 7, 2002 and issued on Aug. 10, 2004. The disclosure of the above applications are incorporated herein by reference.
FIELD OF INVENTION
[0002] The invention relates generally to electrical outlet systems.
BACKGROUND OF THE INVENTION
[0003] Efforts are continuously being made to simplify electrical systems or networks, and the components used in these networks which represent a substantial percentage of the labor and material in commercial and residential construction.
[0004] Presently, when it is desired to locate electrical outlets and/or electrical control modules such as switches, rheostats, or any other similar electrical control module that monitors or controls the flow of electricity, on opposite sides of a common wall or partition, an electrician typically installs separate electrical boxes facing in opposite directions. Electrical outlets are sometimes referred to as electrical sockets or receptacles, but will be referred to as electrical outlets herein. Additionally, each electrical box is typically installed on wall structural supports, e.g. wall studs. This procedure is time consuming and involves using extra electrical wire, boxes, standoffs, conduit and other components used during installation of an electrical wiring network, or system. Further, the electrician must avoid cavities in the walls that will not accommodate two electrical boxes in a certain area of the wall or partition. For example, electrical boxes cannot be installed between studs that define a cold air return space.
[0005] Additionally, electrical outlets and control modules are typically installed by attaching wires to screws appending from the sides of the outlet or the sides of the control module. These screws can present a safety hazard when they are connected within a live electrical wiring network, e.g. having live electrical current flowing through the network, and come into contact with a conductive surface, such as a metal electrical box or metal wall stud. Also, if the electrical outlet or control module is connected to a live wiring network, a person could be severely shocked upon contacting the screws. Furthermore, the screws can cause accidental injuries to the hands of the person installing the outlet or the control module if a screwdriver that is used to tighten the screws slips off one of the screws.
[0006] Through-way electrical boxes have been developed in an attempt to reduce the additional labor and material costs incurred in the installation of electrical wiring networks. However, known through-wall boxes do not allow for using one cavity in a wall to install electrical outlets and/or control modules on opposing sides of the wall without subjecting the electrician, or person installing the outlets and/or control modules, to time consuming mechanical detail work. Some known through-wall boxes require numerous components and fittings which must be adjusted during the installation process, while other known through-wall boxes are not suitable for installing multiple electrical outlets and/or control modules on each side of the wall.
[0007] Additionally, plaster ring plates that cover existing electrical boxes, also referred to herein as frames, typically include an aperture for receiving the electrical outlet and/or control module that is centered in the frame. This placement of the aperture does not permit the most efficient use of space within the electrical box nor ease of electrical outlet and/or control module installation in a back-to-back installation.
[0008] Furthermore, at least some electrical codes require the electrician to install pigtails on each outlet and control module, which are then connected to the incoming power source, e.g. the electrical wiring network, with electric wire nuts. The installation of pigtails is labor intensive and increases the material costs of installing outlets and control modules.
[0009] Thus, it would be desirable to develop a system that provides access to an electrical wiring network from opposing sides of a wall. More specifically, it would be desirable to provide a through-wall electrical system that overcomes the shortcoming of known through-wall systems, thereby reducing labor and material costs of installing such systems. For example, it would be desirable to provide a through-wall electrical system that reduces the complicity of installation caused by numerous components and fittings that must be adjusted during the installation process. Thus, the system should be suitable for installing multiple electrical outlets and/or control modules on each side of the wall, and should also reduce the risks associated with connecting the outlets and/or control modules to the wiring network via screws appending from the outlets and control modules. Additionally, the system should also satisfy code requirements to connect pigtails to the outlet and/or control module prior to connecting the module.
BRIEF SUMMARY OF THE INVENTION
[0010] In various embodiments of the present invention, an electrical wiring system is provided for use in an AC electrical power distribution circuit including a plurality of AC electric power transmitting wires configured to be disposed between an AC power distribution point and a device box, wherein the device box includes a wiring ingress aperture and an open front face for accessing an interior of the device box. The plurality of AC electric power transmitting wires are routed through the wiring ingress aperture and extend into the interior of the device box. The system includes a plug connector device configured to terminate the plurality of AC electric power transmitting wires accessible via the open front face of the device box using a termination arrangement. The plug connector device and the termination arrangement are arranged in a detached relationship relative to the device box after termination. The system additionally includes an electrical wiring device configured to be mountable to the open front face of the device box and includes at least one AC electric circuit element disposed in a device housing having a front cover joined to a rear body member. The electrical wiring device further includes at least one electrical interface operatively coupled to the at least one circuit element and configured to direct AC electric power to an electrical load. The electrical wiring device also includes a receptacle disposed in the body member, wherein the receptacle is configured to receive the plug connector device such that electrical continuity is established between the at least one AC electric circuit element and the plurality of AC electric power transmitting wires when the plug connector device is inserted into the receptacle.
[0011] In other embodiments of the present invention, a method is provided for installing an electrical wiring system in an AC electrical power distribution circuit including a plurality of AC electric power transmitting wires configured to be disposed between an AC power distribution point and a device box. The device box includes a wiring ingress aperture and an open front face for accessing an interior of the device box, and the plurality of AC electric power transmitting wires are routed through the wiring ingress aperture and extend into the interior of the device box. The method includes terminating the plurality of AC electric power transmitting wires, accessible via the open front face of the device box, with a plug connector, wherein the plug connector terminates the plurality of AC electric power transmitting wires using a termination arrangement. The plug connector device and the termination arrangement are arranged in a detached relationship relative to the device box after termination. The method additionally includes providing an electrical wiring device including at least one AC electric circuit element disposed in a device housing that includes a front cover joined to a rear body member. The electrical wiring device further including at least one electrical interface operatively coupled to the at least one AC electric circuit element and configured to direct AC electric power to an external electrical load, and the electrical wiring device also includes a receptacle disposed in the rear body member. Furthermore, the method includes inserting the plug connector into the receptacle to thereby establish electrical continuity therebetween.
[0012] In yet other embodiments of the present invention, an electrical wiring is provided. The system includes an electrical wiring device that includes at least one AC electric circuit element disposed within a device housing, and at least one electrical interface operatively coupled to at least one circuit element and configured to direct AC electric power to an electrical load. The electrical wiring device also includes a predefined area in which a first plurality of electrical contacts are positioned. The system additionally includes a connector device configured to be positioned in contacting relation with the electrical wiring device. The connector device includes a plurality of termination elements configured to terminate a plurality of AC electric power transmitting wires extending through a wiring ingress aperture of a device box and accessible via an open front face of the device box. The termination elements and the connector device are arranged in a detached relationship relative to the device box after termination. The connector device additionally includes a second plurality of electrical contacts disposed in the connector device and electrically coupled to the plurality of termination elements. The second plurality of electrical contacts are configured to be placed in electrical contact with the first plurality of electrical contacts when the connector device is coupled in contacting relation with the electrical wiring device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention will become more fully understood from the detailed description and accompanying drawings, wherein;
[0014] FIG. 1 is a schematic of a system for accessing an electrical wiring network from opposing sides of a common wall, in accordance with a preferred embodiment of the present invention;
[0015] FIG. 2 is a perspective view of a frame used in the system shown in FIG. 1 ;
[0016] FIG. 3 is a perspective view of an electrical outlet used in the system shown in FIG. 1 ;
[0017] FIG. 4 is a perspective view of an alternate embodiment of the electrical outlet shown in FIG. 3 ; and
[0018] FIG. 5 is a schematic of an alternate embodiment of the system shown in FIG. 1 including a plurality of electrical control modules.
DETAILED DESCRIPTION OF THE INVENTION
[0019] FIG. 1 is a schematic of a system 10 for accessing an electrical wiring network 16 from opposing sides of a common wall or partition (not shown), in accordance with a preferred embodiment of the present invention. Wiring network 16 , sometimes referred to as an electrical system, is a network of wires installed in a building or other structure that provide and distribute electrical power throughout the building or structure. Wiring network 16 includes a plurality of network branches 22 which are installed inside the walls or partitions of the building or structure, thereby providing and distributing power throughout the building or structure. As used herein, the term plurality is defined as at least two. Wiring network 16 is typically connected to a load center (not shown), also referred to as a breaker box or fuse box, which is the incoming point for electrical service to a residential or commercial building. However, for smaller buildings or structures other than buildings, wiring network 16 may be a sub-network of a larger wiring network and therefore not directly connected to a breaker box.
[0020] It is generally known that walls and partitions are typically constructed of at least one structural support, such as a wall stud, and have a wall or partition surface attached to opposing sides of the structural support. System 10 includes a through-wall electrical box 28 that is mounted to one of the structural supports using mounting devices 34 prior to the wall surface being attached to the structural support. Although electrical box 28 is shown in FIG. 1 as having a rectangular shape, it is envisioned that electrical box 28 could have any suitable shape, such as circular, oval, or square. Mounting devices 34 include mounting apertures 36 for receiving nails, screws, or any other fastening device suitable to mount electrical box 28 to the wall or partition structural support. Electrical box 28 is constructed of any material suitable for use in electrical wiring networks, such as plastic or metal. Although mounting device 34 is shown in FIG. 1 as an L-shaped bracket coupled to electrical box 28 , it should not be so limited. Mounting device 34 could be any device, system or apparatus suitable for mounting any type of electrical box or similar device to the structural support of a wall or partition, as is well known by those skilled in the art.
[0021] Electrical box 28 includes a perimeter wall 40 and two open sides 46 located at opposing ends of perimeter wall 40 thereby defining a passageway through electrical box 28 . In a preferred embodiment, perimeter wall 40 has a depth ‘d’ approximately equal to the width of the structural support to which it is to be mounted. Therefore, electrical box 28 is constructed such that perimeter wall 40 has a specific predetermined depth ‘d’ that is based upon the width of the structural support used to construct the wall in which electrical box 28 is to be installed. Additionally, in the preferred embodiment, perimeter wall 40 has a uni-body molded construction or is constructed from a single piece of material joined at opposing ends. In an alternate embodiment, electrical box 28 is constructed such that perimeter wall 40 is adjustable to be adapted to walls of various thicknesses. In another alternate embodiment, perimeter wall 40 is constructed of at least two pieces of material joined end-to-end. In yet another embodiment, electrical box 28 is constructed such that perimeter wall 40 has a depth ‘d’ approximately equal to the width of the structural support plus twice the thickness of the wall surface that is to be attached to both sides of the structural support. Thus, perimeter wall 40 would have a depth ‘d’ that extends past both outer edges of the structural support a distance approximately equal to the thickness of the wall surface.
[0022] Additionally, electrical box 28 includes at least one wiring aperture 52 that allows at least one network branch 22 to pass therethrough. Wiring aperture 52 is shown in FIG. 1 as a wiring aperture commonly known in the art as a knockout, but should not be so limited. Wiring aperture 52 could be any suitable aperture in electrical box 28 configured to allow at least one network branch 22 to pass therethrough. For example, wiring aperture 52 could be an aperture in electrical box 28 fashioned to provide a strain relief feature that allows network branch 22 pass therethrough, but inhibits network branch 22 from being easily retracted from wiring aperture 52 . Although FIG. 1 shows wiring network 16 and network branches 22 free from an enclosure, such as electrical conduit, it is envisioned that wiring network 16 may include a plurality of interconnectable enclosure sections, for example electrical conduits. The interconnectable enclosure sections enclose network branches 22 , are connected to the structure, and coupled at one end to electrical box 28 utilizing a wiring aperture 52 . Therefore, it is to be understood that wiring aperture 52 may be formed in perimeter wall 40 in any known manner for accommodating one or more enclosure sections that enclose and provide protection for network branches 22 .
[0023] System 10 further includes a pair of frames 58 that are coupled to electrical box 28 at open sides 46 prior to the wall covering being coupled to the structural support. Frames 58 are sometimes referred to in the art as plaster rings or plaster frames, and are constructed of any material suitable for use in electrical wiring networks, such as plastic or metal. In the preferred embodiment, frames 58 are coupled to electrical box 28 using a plurality of screws 64 inserted through a plurality of frame slots 70 . Alternatively, frames 58 are coupled to electrical box 28 in any other suitable manner. For example, frames 58 could include apertures through which screws 64 would be inserted, or screws 64 could be replaced with any other type of suitable connector such as, rivets or nylon press-in snap retainers. Further yet, frames 58 could be hingedly connected at one side of perimeter wall 40 and coupled to perimeter wall 40 at the opposing side using any type of connector such as screws, rivets, a latch, or nylon press-in snap retainers. Frames 58 are further described below in reference to FIG. 2 .
[0024] In the preferred embodiment, system 10 includes at least one electrical outlet 76 that includes a plurality of integral leads 82 . Again, plurality as used herein means at least two. At least one lead 82 is connected to a network branch 22 thereby providing electrical power to the respective electrical outlet 76 , that is coupled to one frame 58 . Electrical outlet 76 provides a source of, or connection point to, electricity flowing through electrical network 16 . A person accesses the electricity by inserting a suitable plug adapter connected to any device that utilizes electricity (not shown), into mating electrical receptor holes 88 in electrical outlet 76 . Electrical outlet 76 is sometimes known in the art as an electrical socket, or an electrical receptacle, but will be referred to herein as an electrical outlet. Electrical outlet 76 is further described below in reference to FIG. 3 .
[0025] FIG. 2 is a perspective view of one of the frames 58 shown in FIG. 1 . As described above, frames 58 couple to electrical box 28 (shown in FIG. 1 ) at open sides 46 (shown in FIG. 1 ) prior to the wall surface being coupled to the structural supports. Although frame 58 is shown in FIG. 2 having a rectangular shape it should not be so limited. It is envisioned that frame 58 could have any suitable shape, such as circular, oval, or square. Each frame 58 includes a frame aperture 94 that is located off-center in frame 58 , such that a centerline ‘C’ of aperture 94 is substantially closer to one edge of frame 58 than the opposing edge of frame 58 . Aperture 94 receives electrical outlet 76 (shown in FIG. 1 ) when outlet 76 is coupled to frame 58 . In an alternate embodiment, aperture 94 of at least one frame 58 receives at least two electrical outlets 76 . Although aperture 94 is shown in FIG. 2 having a rectangular shape, it is envisioned that aperture 94 could have any suitable shape, such as circular, oval, or square, and could have dimensions larger or smaller with respect to the overall size of frame 58 than is shown in FIG. 2 . In the preferred embodiment, aperture 94 includes a raised lip 100 extending along the perimeter of aperture 94 that has a predetermined height approximately equal to a thickness of the wall surface to be coupled to the structural support on which outlet box 28 is mounted. Raised lip 100 includes a plurality of tabs 106 that include threaded tab holes 112 . Outlet 76 is mounted within aperture 94 by coupling outlet 76 to tabs 106 . In an alternative embodiment, aperture 94 includes at least two raised lips 100 located at separate points along the perimeter of aperture 94 , and each lip 100 includes at least one tab 106 that includes at least one threaded hole 112 .
[0026] FIG. 3 is a perspective front and back view of electrical outlet 76 used in the system 10 (shown in FIG. 1 ). As described above, outlet 76 includes a plurality of integral leads 82 wherein at least one lead 82 is connected to wiring network 16 (shown in FIG. 1 ). Additionally, outlet 76 includes an internal conductive electrical receptor structure 114 having a plurality of receptors 116 configured to receive the plug adapter when the plug adapter is inserted through mating electrical receptor holes 88 . Integral leads 82 are connected to electrical receptor structure 114 such that when outlet 76 is connected to wiring network 16 , via leads 82 , electrical current is provided at outlet 76 accessible via electrical receptor holes 88 . Furthermore, each electrical outlet 76 includes at least one outlet mounting bracket 118 that includes at least one mounting hole 124 . In the preferred embodiment, outlet 76 is coupled to frame 58 (shown in FIG. 1 ) by inserting a screw through outlet mounting bracket hole 124 and threading the screw into tab hole 112 (shown in FIG. 1 ). Alternatively, outlet 76 can be mounted to one of frames 58 by inserting a rivet or nylon press-in snap retainer through bracket hole 124 and into tab hole 112 , or by any other suitable means.
[0027] Electrical outlet 76 further includes an outlet housing 130 constructed of a non-conductive material, such as plastic or rubber. In addition to being constructed of a non-conductive material, outlet housing 130 has a comprehensively non-conductive outer surface 136 free from conductive appendages or surfaces that are electrically active, or live, when outlet 76 is connected to wiring network 16 . Known electrical outlets do not include leads 82 , but instead typically include metal screw posts appending from the outlet housing to which a wiring network is connected either directly or via pigtails connected to the metal screw posts. In the present invention, the entire outer surface 136 of each outlet housing 130 is free from any actively conductive appendages or surfaces, such as metal screw posts, or any other actively conductive metal appending from, protruding from, attached to, or otherwise exposed via an aperture in outlet housing 130 that would be in contact with or connected to wiring network 16 .
[0028] As used herein ‘actively conductive’ appendage or surface is defined to mean any appendage or surface that is designed to have live current flowing through it once outlet 76 is connected to wiring network 16 as described herein. Therefore, when wiring network 16 is connected to an outlet 76 , outlet housing outer surface 136 can be contacted by a person, or come into contact with a conductive surface, such as an outlet box 40 constructed of metal, without the risk of electrical shock or shorting. It is envisioned that housing 130 is of two part construction comprising a first part having receptor holes 88 and a second part from which leads 82 extend.
[0029] Each lead 82 includes a proximal end 142 , a distal end 148 , a wire 154 , and an insulating layer 160 covering wire 154 . Insulating layer 160 is constructed of any electrically insulating material, such as plastic or rubber. In the preferred embodiment, at least one lead 82 has a predetermined length of insulating layer 160 pre-stripped from distal end 148 thereby exposing a predetermined length of wire 154 . Outlet 76 is thereby connected to wiring network 16 by connecting the pre-stripped end of at least one lead to a network branch 22 . In an alternate embodiment, insulating layer 160 covers wire 154 from proximal end 142 to distal end 148 , and outlet 76 is connected to wiring network 16 by stripping a desired length of insulating layer 160 from at least one lead 82 , thereby exposing a desired length of wire 154 , then connecting the exposed length of wire 154 to a network branch 22 .
[0030] In the preferred embodiment, proximal end 142 of each lead 82 extends through outlet housing 130 and is connected to actively conductive electrical receptor structure 114 inside outlet 76 such that each lead 82 is integrally formed, or assembled, with outlet 76 . Proximal ends 142 are connected to receptor structure 114 inside outlet 76 using any suitable means such as soldering ends 142 to receptor structure 114 , or using a crimping type connection, or using any type of suitable connector assembly, e.g. a jack, a plug, or a strain relief. Therefore, leads 82 are integrally formed or assembled with outlet 76 .
[0031] Furthermore, in the preferred embodiment, leads 82 extend from a back side 166 of outlet housing 130 . Alternatively, leads 82 can extend from any other side of outlet housing 130 . It is envisioned that outlet 76 is suitable for use as part of system 10 , as described above, and also suitable for use as a stand-alone electrical outlet for use in conjunction with other known types and configurations of outlet boxes. Additionally, in the preferred embodiment, leads 82 all extend individually from housing 130 . In another alternate embodiment, leads 82 are bundled together inside a non-conductive casing and only a predetermined length of each distal end 148 extends past a distal end of the non-conductive casing.
[0032] FIG. 4 is an alternate embodiment of outlet 76 wherein outlet 76 includes a first connector 161 of a connector module 162 . First connector 161 is connected to receptor structure 114 . Additionally, the proximal ends 142 of each lead 82 are connected to a mating second connector 163 of connector module 162 , thereby forming a subassembly that can be coupled with and decoupled from first connector 161 . Therefore, the subassembly can be connected to network branch 22 , and outlet 76 can subsequently be connected to network branch 22 by coupling the subassembly second connector 163 with mating first connector 161 of outlet 76 . Connector module 162 can be any suitable electrical connection assembly such as a pronged plug assembly or any suitable modular electrical connection device.
[0033] FIG. 5 is an alternate embodiment of system 10 including a plurality of electrical control modules 172 . Control modules 172 include a plurality of integral leads 178 that are integrally formed or assembled with control module 172 in the same manner and fashion as lead 82 (shown in FIG. 3 ) are integrally formed with outlet 76 (shown in FIG. 3 ). Additionally, integral leads 178 connect to a network branch 22 in the same manner and fashion as leads 82 . Control modules 172 are any electrical control module, such as switches or rheostats that monitor and/or control the flow of electricity. Additionally, control modules 172 connect to frames 58 in the same manner and fashion as electrical outlets 76 (shown in FIG. 1 ). In yet another alternate embodiment, system 10 includes any combination of at least one electrical outlet 76 and at least one control module 172 .
[0034] Although system 10 has been described in conjunction with a commercial or residential electrical supply network, it is envisioned that system 10 could be utilized in conjunction with other networks that are utilized for the transmission of mediums other than electricity, such a light or sound. For example, system 10 could be implemented in conjunction with a fiber optic network, or a low voltage communications network, e.g. telephone network, or a coaxial communication network, e.g. a cable television network, or a satellite communication network, or an audio network, e.g. an audio entertainment network or public address network. In which case outlets 76 and control modules 172 would be outlets and control modules associated with such networks.
[0035] While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims. | 4y
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FIELD OF THE INVENTION
[0001] The invention relates to mounting devices for gas turbine flow path components, and particularly those for mounting shroud ring segments to minimize clearance between the turbine blade tips and the inner surface of the shroud ring segments under steady-state operating conditions.
BACKGROUND OF THE INVENTION
[0002] A gas turbine shaft supports a series of disks. Each disk circumference supports a circular array of radially oriented aerodynamic blades. Closely surrounding these blades is a refractory shroud that encloses the flow of hot combustion gasses passing through the engine at temperatures of over 1400° C. The shroud is assembled from a series of adjacent rings supporting flow path components that are typically made of one or more refractory materials such as ceramics. Shroud rings that surround turbine blades are normally formed of a series of arcuate segments. Each segment is attached to a surrounding framework such as a metal ring called a blade ring that is, in turn, attached to the engine case. Close tolerances must be maintained in the gap between the turbine blade tips and the inner surfaces of the shroud ring segments to ensure engine efficiency. However, the shroud ring segments, blade ring, blades, disks, and their mountings are subject to differential thermal expansion during variations in engine operation, including engine restarts. This requires a larger gap and a corresponding efficiency reduction during some stages of engine operation.
[0003] Differences among coefficients of linear thermal expansion in flow path components and their support structures dictate the magnitude and variability of blade tip clearances. In prior designs, flow path components such as shroud ring segments are attached directly to support structures such as blade rings. Thus, when the support structures expand, the flow path components are pulled with them. This creates a large blade clearance requirement, partly because of the time delay between heating of flow path components and their more-insulated support structures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The invention is explained in the following description in view of the drawings listed below. Herein “axial” means oriented with respect to the axis 16 of the engine turbine shaft 15 . An “axial plane” is a plane that includes the axis 16 .
[0005] FIG. 1 is a conceptual sectional view taken on a plane normal to the turbine axis showing an inner ring 20 according to the invention mounted within an outer ring 22 .
[0006] FIG. 2 is a more detailed sectional view of a joint between upper and lower halves of the inner and outer rings of FIG. 1 .
[0007] FIG. 3 is a perspective view of an upper section of an inner ring 20 A.
[0008] FIG. 4 is an enlargement of an end of the inner ring of FIG. 3 .
[0009] FIG. 5 is an enlargement as in FIG. 4 from a viewpoint parallel to the axis.
[0010] FIG. 6 is a sectional view, taken on an axial plane, of a shroud ring segment 24 mounted in an inner ring 20 which is in turn mounted in an outer blade ring 22 .
[0011] FIG. 7 is a view as in FIG. 6 with the shroud ring segment 24 exploded for clarity.
[0012] FIG. 8 is a view of the inner ring formed from first and second halves.
[0013] FIG. 9 is a view of an alternate embodiment of the alignment tabs 46 and 50 and tab slots 48 .
[0014] FIG. 10 illustrates an assembly method for the inner and outer rings and mounts.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The present inventors have recognized that isolating the thermal expansion of a shroud ring from that of its support structure could minimize differential radial expansion rates between the shroud ring and turbine blades during engine operational transients. This would allow minimizing the radial expansion rate of the shroud ring, thus allowing less clearance between the blades and the shroud ring, increasing power output and efficiency.
[0016] FIG. 1 is a conceptual view of a cross section of a gas turbine 14 with a turbine shaft 15 , a shaft axis 16 , a disk 17 , and blades 18 in a case 19 . An inner ring 20 according to the invention is mounted within an outer ring 22 . Shroud ring segments 24 are mounted on the inner ring 20 . The outer ring 22 may be made of a first material with a first coefficient of linear thermal expansion, and the inner ring 20 may be made of a second material with a lower coefficient of thermal expansion than that of the first material. The inner ring 20 is attached to the outer ring 22 by a plurality of radially slidable mounts 26 , 28 that allow radial sliding movement between the inner and outer rings 20 , 22 . A clearance 30 between the rings 20 , 22 provides radial clearance for differential expansion of the rings. The mounts 26 , 28 allow the inner ring 20 to expand independently of the outer ring 22 in order to match the radial expansion characteristics of the turbine blade tips 32 . A material with a relatively low coefficient of thermal expansion is suggested for the inner ring 20 . In one embodiment, a nickel-iron-cobalt alloy sold under the trade name designation INCOLOY® alloy 909 (UNS NI9909) may be used. INCOLOY alloy 909 is known to have the following chemical composition: nickel 35.0-40.0%; cobalt 12.0-16.0%; niobium 4.3-5.2%; titanium 1.3-1.8%; silicon 0.25-0.50%; aluminum 0.15 maximum; carbon 0.06 maximum; iron balance. A material for the inner ring may be further selected for improved wear and oxidation resistance at elevated temperatures.
[0017] As shown in FIG. 2 the inner ring 20 may have first and second halves or sections 20 A, 20 B that are bolted together at a joint 34 . A pair of bolts 36 may pass through the abutting ends of the sections 20 A, 20 B to connect them. Recessed holes 38 for such bolts 36 are shown in FIGS. 3 and 4 , which also show segment locking holes 55 . As shown in FIGS. 4 , 5 and 8 a key clamp 40 is defined in each joint 34 between the upper and lower sections 20 A, 20 B of the inner ring 20 .
[0018] The outer ring 22 may also have first and second halves or sections 22 A, 22 B that are similarly joined at abutting ends. The resulting joint 42 forms a key slot 44 in the outer ring 22 opposite the key clamp 40 in the inner ring 20 . A key 46 may be clamped in the key clamp 40 as shown in FIG. 2 , and the bolts 36 may pass through it. The key 46 is radially slidable in the key slot 44 . This mounting mechanism fixes the rotational position of the inner ring 20 , but allows relative radial movement between the inner ring 20 and the outer ring 22 . Alternately (not shown) the key 46 may be fixed in the outer ring 22 and slidable in the inner ring 20 , or slidable in both rings.
[0019] Upper and lower tabs slots 48 and tabs 50 may be provided on the outer and inner rings 20 , 22 as illustrated in FIG. 1 . The tabs 50 slide radially in the tab slots 48 . The interfacing of these tab slots 48 and tabs 50 keeps the inner ring 20 centered laterally within the outer ring 22 . Alternately as in FIG. 9 the tabs 50 may be disposed on the inner ring 20 , and the tab slots 48 may be on the outer ring. Alternately (not shown) the inner ring 20 may be made in four sections, and the tabs 50 may be formed using keys 46 at the resulting upper and lower joints 28 similarly to the other two joints 26 shown.
[0020] The key slots 44 and/or the tab slots 48 may be formed as enclosed chambers except for an open radially inner end that receives the key 46 or tab 50 . Such a chamber fixes the inner ring 20 in the outer ring 22 against movement parallel to the turbine axis 16 . Thus, the only freedom of movement between the inner and outer rings is a centered radial expansion. However, not all of the key slots 44 and tab slots 48 need be axially restrictive. A combination of four radially slidable mounts 26 , 28 at four cardinal points as shown is ideal because it maintains a coaxial relationship of the rings 20 , 22 , while allowing differential radial expansion of them, and allowing assembly of them.
[0021] For assembly 70 as illustrated in FIG. 10 , the lower half of the inner ring 20 B may be inserted 72 into the lower half of the outer ring 22 B along the radial direction allowed by the tab slots 48 and tabs 50 . This forms a lower half inner/outer ring assembly, which is then rolled 74 into the engine, with or without the rotor in place. Before the upper half of the ring assembly is made, the rotor must be in place 75 . A respective key 46 is then placed 76 in each end of the lower half of the inner ring 20 B. The upper and lower sections 20 A, 20 B of the inner ring are then bolted together 77 , 78 , clamping the respective keys 46 between them. Finally, the upper outer ring section 22 A is lowered 79 over the upper inner ring section 20 A along the radial direction allowed by the tab slots 48 and tabs 50 . The upper and lower outer ring sections 22 A, 22 B are then connected together 80 , trapping the keys 46 . This retains the keys 46 radially slidably within the key slots 44 in the abutting ends of the outer ring sections 22 A, 22 B.
[0022] As shown in FIGS. 6-7 shroud ring segments 24 may be assembled onto the inner ring halves 20 A, 20 B by sliding the shroud ring segments 24 into tracks 52 in each inner ring half 20 A, 20 B before the other assembly steps above. Alternately the shroud ring segments 24 may be assembled onto the inner ring 20 by other means known in the art. A track-and-slide assembly geometry is illustrated in FIGS. 6-7 , which also show air cooling channels 54 and gas seals 56 . Bosses 58 are provided for mounting the outer ring 22 to the engine case 19 .
[0023] While various embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only. Numerous variations, changes and substitutions may be made without departing from the invention herein. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims. | 4y
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This patent claims the benefit of the filing date of the following U.S. provisional patent application 61/094,678, filed Sep. 5, 2008.
TECHNICAL FIELD
The subject invention generally relates to hand-held walking stilts.
BACKGROUND
Hand-held walking stilts can be used in physical education classes as a way of improving balance and coordination. People may also use walking stilts for exercise, for recreation, and as a toy. Walking stilts are commonly categorized as “pole-type” stilts, in which a hand-pole extends from a foot-base; and as “rope-type” stilts, in which a hand-rope extends from a foot-base. The pole or the rope extending from the base can be gripped to help with walking and balance.
SUMMARY OF THE INVENTION
According to one version of the invention, there is a hand-held walking stilt comprising a base that contacts a walking surface. The base has a foot stand to support a user's foot a set distance above the walking surface, where the foot stand defines an opening for a pole. The base also has at least one base flange extending into the opening. There is also a pole adapted to extend through the opening in the foot stand, and to extend above the base away from the walking surface, with the pole having at least one pole flange that interconnects with the base flange to hold the base and the pole together.
According to another version of the invention, there is a method of assembling a hand-held walking stilt, the method comprising the steps of: providing a base that supports a user's foot above a walking surface and that has an opening with at least one base flange, and providing a pole that is grasped by a user's hand and that has at least one pole flange; inserting the pole into the opening such that the pole projects upward from the base; and twisting the pole in a first direction to overlap the base flange and the pole flange in order to connect the base and the pole together.
According to yet another version of the invention, there is a hand-held walking stilt comprising a base that contacts a walking surface, where the base has a foot stand to support a user's foot a predetermined distance above the walking surface, with the base defining an opening with an inner surface, and at least one helical base flange that extends from the inner surface and into the opening. There is also a pole adapted to be grasped by a user's hand that is receivable in the opening, with the pole having an end having at least one helical pole flange that extends from the end. The helical base flange is adapted to overlap with the helical pole flange to connect the pole and the base together in a threading manner when twisted in a first direction, and the helical base flange is adapted to separate from the helical pole flange in an un-threading manner when twisted in a second direction to disconnect the pole and the base from each other.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 shows students using example embodiments of hand-held walking stilts;
FIG. 2 is a top perspective view of an embodiment of a hand-held walking stilt having a base and a pole connected together;
FIG. 3 is a bottom perspective view of the hand-held walking stilt;
FIG. 4 is an enlarged top perspective view of an end of the pole;
FIG. 5 is an enlarged bottom perspective view of the end of the pole;
FIG. 6 is a perspective view of the base;
FIG. 7 is a bottom view of the pole showing pole flanges;
FIG. 8 is a bottom view of the base showing base flanges;
FIG. 9 is an enlarged view showing the pole and base flanges initially interconnected;
FIG. 10 is a section view taken along arrows 10 - 10 of FIG. 9 ;
FIG. 11 is an enlarged view showing the pole and base flanges interconnected about midway;
FIG. 12 is a section view taken along arrows 12 - 12 of FIG. 11 ;
FIG. 13 is an enlarged view showing the pole and base flanges finally interconnected;
FIG. 14 is a section view taken along arrows 14 - 14 of FIG. 13 ;
FIG. 15 is a bottom perspective view of the base joined to a rope; and
FIG. 16 is a side view of an embodiment showing the contour of the bottom of the base.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, FIGS. 1-15 show an example embodiment of a hand-held walking stilt generally shown at 10 that supports a user's foot and that can be grasped by a user's hand during use. The hand-held walking stilt 10 is designed for use as a pole-type stilt or a rope-type stilt. The hand-held walking stilt 10 includes a base generally indicated at 12 , a pole generally indicated at 14 that is connectable with the base, and a rope generally indicated at 16 that is joinable to the base.
The base 12 directly contacts a walking surface during use, and supports a user's foot a predetermined or set distance above the walking surface. Referring to FIGS. 2 , 3 , and 6 , the base 12 has a generally bucket-shape with an open-end 18 extending to a closed-end 20 via a circumferential wall 22 . As shown best in FIG. 16 , the open-end 18 has a leading raised section 24 and a trailing raised section 26 formed in a non-planar curled edge 28 of the open-end. The leading and trailing raised sections 24 , 26 facilitate stepping over the walking surface by complementing a natural step from the leading, or toe end, to the trailing, or heel end. When at rest, the leading and trailing raised sections 24 , 26 arc above a flat walking surface beneath. The circumferential wall 22 tapers radially toward the closed-end 20 such that the open-end 18 has a larger diameter than the closed-end, and such that a number of bases can be partially telescoped and stacked one-on-top-of-another to store the bases during nonuse and shipping. The circumferential wall 22 has a pair of holes 30 located opposite one another for receiving an unknotted rope end which can then be knotted to join the rope 16 to the base 12 (shown best in FIG. 15 ). Other embodiments can have a single hole or can have more than two holes.
A foot stand 32 is located at the closed-end 20 and serves as a platform for supporting a user's foot. Referring to FIGS. 3 and 6 , on one side, the foot stand 32 has a number of traction beads 34 protruding from an exposed surface 36 for creating friction between the user's foot and the foot stand 32 to help prevent the user's foot from unintentionally sliding off of the foot stand. On the other side, a number of strengthening ribs 38 criss-cross each other on an unexposed surface 40 to help structurally support the foot stand 32 while carrying the weight of the user.
The base 12 further has an opening 42 located in the foot stand 32 . Referring to FIGS. 6 and 8 , the opening 42 is sized to receive the pole 14 and has an inner surface 44 . One part of an interconnecting structure is located in the opening 42 and extends from the inner surface 44 . The interconnecting structure provides a quick-connect and disconnect feature that allows the pole 14 to be coupled to the base 12 and then removed from the base as desired. The other part of the interconnecting structure is located on the pole 14 as will be described in more detail below. The interconnecting structure can come in various forms that temporarily secure the base 12 and the pole 14 together by one or more actions, including inserting and twisting. In the example shown, first, second, and third partially helical base flanges 46 , 48 , and 50 extend from the inner surface 44 and into the opening 42 , and are spaced equally around the inner surface.
Each base flange has a first circumferential end 52 and a second circumferential end 54 that is inclined toward the foot stand 32 so that each base flange is ramped from the first circumferential end to the second circumferential end. Each base flange also has an upper surface 56 and a lower surface 58 , and each upper surface has a base rib 60 located about midway between the circumferential ends and protruding axially from the upper surface. It should be appreciated that other interconnecting structures are possible that have not been shown or described. For example, a single helical base flange may extend around the inner surface 44 , a pair of partially helical base flanges may extend around the inner surface, and more than three partially helical base flanges may extend around the inner surface. Moreover, the base flanges need not necessarily be helical and instead could be axially staggered on the inner surface 44 with respect to each other.
The pole 14 is connectible with and disconnectible from the base 12 and, when connected, extends above the base and away from the walking surface. Referring to FIGS. 2 , 4 , 5 , and 7 , the pole 14 is designed to be grasped by a user's hand, but could have other designs including one with shoulder rests, for example. The pole 14 has an elongated body 62 that extends from a first end 64 to a second end 66 . The other part of the interconnecting structure is located near the second end 66 and complements the construction of the interconnecting structure located on the base 12 . In this example, a first, second, and third partially helical pole flange 68 , 70 , and 72 protrude away from the body 62 and are spaced equally around the body. A flange support 88 supports each flange 68 , 70 , 72 .
Each pole flange has a first circumferential end 74 and a second circumferential end 76 that is inclined toward the first end 64 so that each pole flange is ramped from the first circumferential end to the second circumferential end. Each pole flange also has an upper surface 78 and a lower surface 80 . In this example, the first pole flange 68 has a pole rib 82 located near the second circumferential end 76 and protruding from the lower surface 80 . The second circumferential end 76 of the first pole flange 68 extends farther than the other second circumferential ends so that it slightly overlaps the neighboring circumferential end of the third pole flange 72 . The first pole flange 68 also has a space 83 formed between the body 62 and the first pole flange to allow the second circumferential end 76 to flex during connection. In other examples, one or both of the other pole flanges may also have a pole rib, may have a recess, or may have a combination thereof. Like the base flanges, other interconnecting structures for the pole flanges are possible that have not been shown or described.
The rope 16 can be joined with and unjoined from the base 12 as desired. Referring to FIG. 15 , the robe 16 has a first and second free end 84 , 86 that can be inserted into the holes 30 and knotted for joining the rope to the base 12 . To unjoin the rope 16 and base 12 , the free ends can be unknotted and pulled out of the holes 30 . The rope can be actual woven rope or an elongated piece of plastic that is extruded in solid or tube form.
In use, the hand-held walking stilt 10 can be interchangeably configured to function as a pole-type stilt or a rope-type stilt. Beginning with the base 12 by itself, to connect the pole 14 , the first end 64 of the pole is inserted through the open-end 18 and then through the opening 42 . The pole 14 is advanced through the opening 42 until the pole flanges and the base flanges confront one another as best shown in FIG. 3 . The pole 14 is then twisted in a first direction A in a threading manner such that the pole flanges overlap and lock with the base flanges. Referring to FIGS. 9 and 10 , the second circumferential ends 76 of each pole flange initially engage the first circumferential ends 52 of each base flange when the upper surfaces 78 of each pole flange lay against the lower surfaces 58 of each base flange. Referring to FIGS. 11 and 12 , as twisting progresses, the lower surfaces 80 of each pole flange ride over the upper surfaces 56 of each base flange. The pole and base flanges lay on top of one another in an overlapping arrangement. Referring to FIGS. 13 and 14 , when finally positioned the pole rib 82 flexes and snaps over the base rib 60 and is caught thereby, thus preventing twisting in a second and opposite direction and temporarily coupling the pole 14 and base 12 together. The pole and base flanges' overlapping arrangement prevents the pole 14 from being pushed or pulled out of the opening 42 . To disconnect the pole 14 , the pole is twisted in the second direction in reverse-threading manner and the pole rib 82 is again snapped over the base rib 60 . The pole 14 is twisted until the pole and base flanges are no longer overlapped and the pole is reversed out of the opening 42 . Whether the pole 14 is connected or disconnected, the rope 16 can be joined to the base 12 as described above. The construction and location of the interconnecting structure permits stacking of a number of bases without interference.
The invention has been described in an illustrative manner, and it is to be understood that the terminology that has been used is intended to be in the nature of words of description rather than of limitation.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described. Moreover, the reference numerals are merely for convenience and are not intended to be in any way limiting. | 4y
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/565,519, filed Apr. 27, 2004, which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a composite membrane suitable for a pervaporation process, to its preparation, and to its use in the separation of fluids in a pervaporation process.
BACKGROUND OF THE INVENTION
[0003] The separation or removal of water from organic liquids is an important process within the chemical, petrochemical, and energy industries. Water removal is important in the primary production of a wide range of organic solvents, in the recovery and recycling of used solvents, and in the removal of water from chemical equilibrium reactions to drive the reaction towards a preferred product. Frequently, the removal of water is complicated by the formation of azeotropes of the solvent with water, precluding use of a simple distillation approach to produce an anhydrous solvent. The best example of such a problem occurs in the production of ethanol, where an azeotrope with ca. 95.6% ethanol and 4.4% water is formed. The formation of this azeotrope greatly hinders the production of anhydrous ethanol and significantly adds to cost of this solvent.
[0004] Various processes that have been used to dehydrate organic liquid streams include fractional distillation, fractional distillation using entrainers to overcome the azeotrope problem, adsorption processes, and newer membrane-based techniques such as pervaporation and vapor permeation.
[0005] Pervaporation is a process that involves a membrane in contact with a liquid on the feed or upstream side and a vapor on the permeate or downstream side. Usually, a vacuum or an inert gas is applied on the vapor side of the membrane to provide a driving force for the process. Typically, the downstream pressure is lower than the saturation pressure of the permeate. Vapor permeation is quite similar to pervaporation, except that a vapor is contacted on the feed side of the membrane instead of a liquid. As membranes suitable for pervaporation separations are typically also suitable for vapor permeation separations, use of the term “pervaporation” herein encompasses both “pervaporation” and “vapor permeation”.
[0006] The efficiency of a pervaporation membrane can be expressed as a function of its selectivity and of its specific flux. The selectivity is normally given as the ratio of the concentration of the better permeating component to the concentration of the poorer permeating component in the permeate, divided by the corresponding concentration ratio in the feed mixture to be separated:
α = y w / y i x w / x i
wherein y w and y i are the content of each component in the permeate, and x w and x i are the content of each component in the feed, respectively.
[0007] The trans-membrane flux is a function of the composition of the feed. It is usually given as permeate amount per membrane area and per unit time, i.e. Kg/m 2 hr. In order to obtain a high trans-membrane flux, it is desirable to operate the pervaporation process at the highest possible temperature. However, this means that the membrane will be in contact with a feed mixture, which often has a high concentration of organic components, at high temperature. To achieve an economical lifetime for the membrane, it is preferable that all components of the membrane be durable under such demanding conditions.
[0008] In the pervaporation process, both mass and heat transfer occurs. The solution-diffusion model can describe mass transfer where the selectivity is determined by selective sorption and/or selective diffusion. For pervaporation dehydration membranes, selective sorption is governed by the presence of the active centers in the polymer that are capable of specific interactions with a polar fluid. Selective diffusion is governed by the rigidity and the regularity of the polymer structure and also by the construction of the polymer's interspace.
[0009] A variety of different types of membranes and membrane constructs have been described for use in pervaporation dehydration processes. The materials used to prepare the membranes include hydrophilic organic polymers such as polyvinylalcohol, polyimides, polyamides, and polyelectrolytes. In addition, inorganic materials such as molecular sieves and zeolites have been used.
[0010] Initially, polymer-based pervaporation membranes comprised dense, homogeneous membranes. Typical examples of such membranes are described by Yamasaki et al. [J. Appl. Polym. Sci. 60 (1996) 743-48]. These membranes suffer from low fluxes as they are fairly thick. While the flux of the membranes can be increased by decreasing the thickness of the membranes, this leads to a decrease in mechanical strength and robustness.
[0011] Two routes have been used to overcome the problem encountered by the above homogeneous membranes. The first route involves the use of an asymmetric membrane in which a dense surface layer is supported on a more porous material made from the same polymer. A typical example of such an asymmetric membrane is disclosed by Huang et al. [Sep. Sci. Tech. 28 (1993) 2035-48]. The second route involves the formation of a dense thin film on the surface of a suitable support membrane, wherein the chemical composition of the dense surface layer and the supporting membrane are typically different. Typically, the support membrane is an ultrafiltration membrane that may contain an incorporated fabric to provide additional strength. Examples of these thin film composite membranes are described in U.S. Pat. No. 4,755,299, U.S. Pat. No. 5,334,314, U.S. Pat. No. 4,802,988 and EP 0,381,477. In U.S. Pat. No. 4,755,299, a dense cross-linked polyvinyl alcohol layered composite membrane designed for dehydration of organic solvents is described as having a flux of 0.3 kg/m 2 hr and a selectivity of 250 when separating a solution comprising 80% isopropyl alcohol (IPA) and 20% water at 45° C. One major disadvantage of these thin-film composite membranes, however, is their fragility. For example, the commonly used cross-linked poly(vinylalcohol) films supported on polyacrylonitrile ultrafiltration membrane supports are readily damaged through the formation of cracks in the films and through parts of the film falling away from the support. Great care must therefore be taken when mounting and using these membranes. It is also difficult to prepare such membranes in such a way that they are free of defects.
[0012] A special form of the thin-film composite membranes is referred to as a “Simplex” membrane. These are made up of thin films using alternating layers of oppositely charged polyelectrolytes. The membranes are made by successive immersions in solutions of the two different polylelectrolytes such that a multilayer complex is formed (see for example Krasemann et al. [J. Membr. Sci. 150 (1998) 23-30]; Krasemann et al. [J. Membr. Sci. 181 (2001) 221-8], and Haack et al. [J. Membr. Sci. 184 (2001) 233-43]). In Haack et al., a Simplex membrane with six double layers of poly(ethylenimine) and alginic acid has a selectivity higher than 10,000 and a flux of 0.3 kg/m 2 hr in the pervaporation dehydration of 88 wt. % IPA at 50° C. While a high selectivity and reasonable fluxes can be achieved with the Simplex membranes, these membranes are complex to prepare as they require multiple coating steps. In order to get ideal performance, up to 60 dipping operations are sometimes needed. Another significant drawback lies in the fact that these membranes cannot tolerate feed water contents higher than 25% without loss of some of the multiple layers.
[0013] Mixtures or blends of oppositely charged polymers have been used to form homogeneous dense membranes. However, these membranes typically have low fluxes as they are relatively thick. Shieh and Huang [J. Membr. Sci. 127 (1997) 185-202] disclose homogeneous membranes prepared by casting a solution containing chitosan (positively charged) and polyacrylic acid (negatively charged), to form a polymer blend membrane. The thickness of the resulting membrane is between 20 μm and 40 μm and the performance of this membrane is poor in term of flux (flux of 0.03 kg/m 2 hr and a selectivity of 2216 with a 95 wt. % ethanol/water feed at 30° C.). In another example, Lee et al. [J. Membr. Sci. 52 (1990) 157-72] use dense membranes comprising an interpenetrating polymer network (IPN) of two polymers of opposite charge (acrylic acid and polyurethane) for the pervaporation of ethanol/water mixtures. In this case, the swelling ratio of the cast film is controlled by cation/anion interactions between the two IPNs. This membrane has a rather low selectivity and moderate flux when used for the dehydration of ethanol/water solutions.
[0014] Zeolites and molecular sieves are known to have a high affinity for water. As a result, there has been considerable work focused on trying to incorporate zeolites as the active component or layer in a membrane, and thin zeolite films supported on ceramic membranes display very high fluxes and separation factors with water/alcohol mixtures. However, it is difficult to make these membranes free of defects because of cracking, and these membranes are expensive to prepare. Y. Morigami et al. [Sep. Pur. Tech. 25 (2001) 251-60) have described the first large-scale pervaporation plant using zeolite NaA membrane with tubular-type module. Berg et al. [J. Membr. Sci. 224 (2003) 29-37] prepared high performance zeolite A membranes with Titania support, with some membranes having 3.5 μm thickness and a selectivity of 54,000 and flux of 0.86 Kg/m 2 hr when treating 95 wt. % ethanol/water at 45° C., which significantly outperforms other known membranes. This superior performance is ascribed to the pretreatment of the TiO 2 -support with UV-photons, which improves the hydrophilicity of the support and thus the attachment of the zeolite to the support. However, these membranes are very sensitive to the formation of defects caused by flaws in the support or by incorrect membrane handling. Compared with polymeric membranes, zeolite membranes are generally less swollen, more inert to chemicals and can endure high temperatures. However, zeolite membranes are brittle, and their cost is much higher than for polymeric membranes.
[0015] An alternative approach to the above involves the incorporation of zeolite particles into a polymeric support. Membranes of this type typically have low separation factors, particularly when the fluxes are maximized. For example, Zeolite NaA-filled poly(vinylchloride) (PVC) membranes were reported by Goldman et al. [J. Appl. Polym. Sci. 37 (1989) 1791-800]. By adding NaA zeolite absorbents, the performance of a PVC membrane was changed from a selectivity of 250 and a flux of 0.51 Kg/m 2 h to a selectivity of 7 and a flux of 5.68 Kg/m 2 h. Another example of absorbent-filled membranes was reported by Okumus et al. [J. Membr. Sci. 223(2003) 23-38] where zeolites (3A, 4A and 13×) were added as fillers to a base poly(acrylonitrile) (PAN) membrane. At optimum zeolite content, the flux is increased about nine-fold with a seven-fold loss of selectivity relative to homogeneous PAN membranes.
[0016] Another approach that has been used to form pervaporation membranes is a “pore-filled” construct. Mika et al. [U.S. Pat. No. 6,258,276] disclose that a cross-linked polyelectrolyte incorporated into the pores of a support member can be used for pervaporation dehydration. Membranes consisting of cross-linked poly(4-vinylpyridinium salts) exhibit reasonably high fluxes but very low separation factors in the dehydration of ethanol. These membranes consist of a single charged polymer. There are other reports of pore-filled membranes developed for pervaporation purposes. These include the work of Yamaguchi et al. [Macromolecules 24 (1991) 5522-27] in which methyl acrylate was grafted to the walls of an ultrafiltration (UF) membrane using a plasma activation process. These membranes, which consist of a single polymer within the pores of the membrane, have a flux of 0.5 Kg/m 2 hr and a selectivity of 7 when treating 50 wt. % benzene/cyclohexane at 50° C. Ulbricht et al. [J. Membr. Sci. 136 (1997) 25-33] also describe a pore-filled membrane comprising a grafted acrylate. The impact of side-group functionality (hydrophilicity, size) and preparation parameters (monomer concentration, UV irradiation time) was analyzed using solutions comprising methanol and less polar hydrocarbons. Pervaporation tests with methanol/methyl tert-butyl ether (MTBE) at 50° C. were performed with these membranes, and for methanol feed concentration between 7 and 20%, the fluxes were between 0.75 and 1.5 Kg/m 2 hr and the selectivity between 80 and 45. Hirotsu et al. [J. Appl. Polym. Sci. 36 (1988) 177-89] grafted acrylic acid and acrylamide comonomers into the pores of a polypropylene support member by plasma method, then treated these membranes with a sodium hydroxide solution to get the final ionized membranes. When dehydrating higher than 90 wt. % ethanol solutions, these membranes had both low fluxes and separations.
[0017] Membranes comprising pore-grafted copolymers have also been used to separate solutions. Frahn et al. [J Membr. Sci., 234 (2004) 55-65] describe the separation of aromatic/aliphatic hydrocarbons by photo-modified poly(acrylonitrile) supports, in which supports are grafted non-crosslinked linear copolymers that have, in some instances, both positive and negative groups. One of the problems faced in this system is that the grafted linear copolymers can undergo conformational changes, which changes can adversely affect performance. These membranes display a low separation factor and low fluxes when separating aromatic/aliphatic hydrocarbons. Another problem encountered with non-crosslinked systems is that amount of linear copolymer retained within the support member is quite low unless high light intensities or long irradiation times are used.
[0018] There is therefore a need for high performance membranes (high flux and high selectivity) that are robust, easy to fabricate, and low cost. Most of the known pervaporation membranes have either high flux or high selectivity, but not both features at the same time. Only zeolite based membranes have both higher fluxes and reasonably high selectivities, but they are more expensive than polymeric membranes, their fabrication is complex, and they are susceptible to cracking and to loss of performance.
BRIEF SUMMARY OF THE INVENTION
[0019] The present invention provides a robust, high-performance membrane designed for the selective removal of a polar fluid, such as water, from less polar fluids, such as organic solvents, by a pervaporation process. The composite membrane comprises a support member in which is incorporated a cross-linked copolymer that has both positively and negatively charged functionality in a controlled ratio to give the desired selectivity and flux. By changing the ratio of the charged groups and the amount of the copolymer incorporated into the support, the flux and the selectivity can be controlled for use in specific applications.
[0020] In one aspect, the present invention provides a composite membrane comprising
(a) a support member that has a plurality of pores extending through the support member and (b) a cross-linked copolymer comprising (i) a cationic monomer and an anionic monomer and/or (ii) a zwitterionic monomer, which cross-linked copolymer fills the pores of the support member,
the cross-linked copolymer having a permeability for a fluid that is dependent on the polarity of the fluid, wherein the permeability increases with increasing polarity.
[0023] In another aspect, the present invention provides a pervaporation apparatus comprising the composite membrane as described herein.
[0024] In a further aspect, the present invention provides a process for the preparation of the composite membrane described herein, the process comprising
(i) introducing into the pores of the support member a solution comprising (i) an anionic monomer, a cationic monomer, a cross-linking agent and an initiator, or (ii) a zwitterionic monomer, a cross-linking agent and an initiator, and (ii) reacting the anionic monomer, the cationic monomer and the cross-linking agent or the zwitterionic monomer and the cross-linking agent to form a cross-linked copolymer that fills the pores of the support member.
[0028] In a further aspect, the present invention provides a method for separating fluids of different polarity, a method for dehydrating an aqueous mixture of an organic solvent, and a method for removing a water by-product from a reaction mixture, each method using the composite membrane described herein.
[0029] The above and other objects, features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying figures which illustrate preferred embodiments of the present invention by way of example.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Embodiments of the invention will be discussed with reference to the following Figures:
[0031] FIG. 1 shows SEM images of a poly(acrylonitrile)(PAN) based asymmetric composite membrane: (a) is an image of the dense side (smaller pores) of the PAN based membrane, while (b) is an image of the support layer (larger pores) of the PAN based membrane.
[0032] FIG. 2 is a schematic diagram of the pervaporation apparatus used in the examples.
[0033] FIG. 3 is a graph illustrating the effect of anionic/cationic monomer ratio on the pervaporation performance of pore-filled membranes with 90.9 wt. % IPA/water at 60° C. The anionic monomer is methacrylic acid (MAA), and the cationic monomer is 3-(acrylamidopropyl)trimethylammonium chloride (APTAC).
[0034] FIG. 4 is a graph illustrating the performance of composite membranes as a function of anionic monomer with APTAC comonomer during pervaporation with 91.6 wt. % IPA/water at 60° C. AA: acrylic acid; MAA: methacrylic acid; MAAS: methacrylic acid, sodium salt; AMPS: 2-acryamido-2-methyl-1-propanesulfonic acid; SSAS: 4-styrene sulfonic acid, sodium salt.
[0035] FIG. 5 is a graph illustrating performance of composite membranes as a function of cationic monomer with SSAS comonomer during pervaporation with 89.9 wt. % IPA/water at 60° C. APTAC: 3-(acrylamidopropyl) trimethylammonium chloride; AETAC: [2-(acryloyloxy)ethyl]trimethylammonium chloride; MAETAC: [2-(methacryloyloxy)ethyl]trimethylammonium chloride.
[0036] FIG. 6 is a graph illustrating the performance of an APTAC/MAA (mole ratio 4:1) copolymer filled composite membrane as a function of temperature during pervaporation with 91.2 wt. % IPA/water.
[0037] FIG. 7 is a graph illustrating the performance of an APTAC/AA (mole ratio 9:1) copolymer filled composite membrane as a function of IPA feed concentration during pervaporation with IPA/water at 60° C.
[0038] FIG. 8 is a graph illustrating the effect of anionic monomer content on the dehydration performance of anionic/cationic pore-filled membranes with 95 wt. % ethanol at 70° C. The anionic monomer is 4-styrene sulfonic acid, sodium salt (SSAS), and the cationic monomer is [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MAETAC).
DETAILED DESCRIPTION OF THE INVENTION
[0039] In the composite membrane of the invention, the cross-linked copolymer fills the pores of the support laterally, i.e. substantially perpendicular to the direction of the flow through the composite membrane. By “fill” is meant that, in use, essentially all fluid that passes through the composite membrane must pass through the cross-linked copolymer. A support member whose pores contain cross-linked copolymer in such an amount that this condition is satisfied is regarded as filled. Provided that the condition is met that the fluid passes through the cross-linked copolymer, it is not necessary that the void volume of the support member be completely occupied by the cross-linked copolymer.
[0040] The cross-linked copolymer provides the separating function of the composite membrane in pervaporation separations, and the cross-linked copolymer typically swells in the presence of a polar solvent such as water. In some embodiments, the cross-linked copolymer is a hydrogel. The support member provides mechanical strength to the cross-linked copolymer and it impedes the swelling of the cross-linked copolymer when the cross-linked copolymer is swellable.
[0041] Preferably, the cross-linked copolymer is anchored within the support member. The term “anchored” is intended to mean that the cross-linked copolymer is held within the pores of the support member, but the term is not necessarily restricted to mean that the cross-linked copolymer is chemically bound to the pores of the support member. The cross-linked copolymer can be held by the physical constraint imposed upon it by enmeshing and intertwining with structural elements of the support member, without actually being chemically grafted to the support member, although in some embodiments, the cross-linked copolymer may become grafted to the surface of the pores of the support member.
[0042] The term “cationic/anionic copolymer” when use herein refers to a copolymer prepared with cationic and anionic monomers. By cationic monomer is meant a monomer that has a positive charge or a group that can be ionized to form a positive charge. Similarly, by anionic monomer is meant a monomer that is negatively charged or that has a group that can be ionized to form a negative charge.
[0043] The performance of the composite membrane is mainly determined by the properties of the copolymer anchored within the pores of the support member. The presence of both anionic and cationic sites in the copolymer leads to an increase in intramolecular interactions within the copolymer, leading to a more compact copolymer structure when the copolymer swells in the presence of a polar fluid. This compact nature helps to increase the selectivity of composite membranes, as it provides a denser copolymer structure through which the fluids must pass. The selectivity of the composite membranes is also enhanced by the presence of the support member, as beyond providing mechanical strength, the support member also restricts the swelling of anchored copolymer, which again increases the density of the copolymer.
[0044] The anionic monomers used in this invention are preferably water soluble, although anionic monomers that display little or no solubility in water can be used. Preferred anionic monomers include unsaturated carboxylic acids or salts or anhydrides thereof, and unsaturated sulfonic acids or salts or anhydrides thereof. Unsaturated anionic monomers may contain one, or more than one, carbon-carbon double bond.
[0045] Examples of suitable anionic monomers include acrylic acid, 2-acetamidoacrylic acid, trans-3-benzoylacrylic acid, 2-bromoacrylic acid, 3-chloroacrylic acid, trans-3-(4-chlorobenzoyl)acrylic acid, 2,3-dichloroacrylic acid, 3,3-dichloroacrylic acid, 3,3-dimethylacrylic acid, furylacrylic acid, methacrylic acid, 2-phenylacrylic acid, trans-3-(3-pyridyl)acrylic acid, trichloroacrylic acid, 2-(trifluoromethyl)acrylic acid, propynoic acid (propiolic acid), phenylpropynoic acid, crotonic acid, isocrotonic acid, 3-bromo-2-butenoic acid, 2-chloro-2-butenoic acid, 3-chloro-2-butenoic acid, 2,3-dibromo-4-oxo-2-butenoic acid, 2,3-dichloro-4-oxo-2-butenoic acid, 2,3-dimethyl-2-butenoic acid, 2-ethyl-2-butenoic acid, trans-2-methyl-2-butenoic acid (tiglic acid), cis-2-methyl-2-butenoic acid (angelic acid), 4-oxo-4-phenyl-2-butenoic acid, 2-phenyl-2-butenoic acid, 4,4,4-trifluoro-3-methyl-2-butenoic acid, 3-butenoic acid, 2-hydroxy-4-phenyl-3-butenoic acid, 2-methyl-3-butenoic acid, 2-butynoic acid (tetrolic acid), 2-pentenoic acid, 4-hydroxy-2-pentenoic acid, 2-methyl-2-pentenoic acid (trans), 4-hydroxy-3-pentenoic acid, 4-pentenoic acid, 2,2-dimethyl-4-pentenoic acid, 3-methyl-4-pentenoic acid, 2,4-pentadienoic acid, 2-pentynoic acid, 4-pentynoic acid, 2-hexenoic acid, 2-ethyl-2-hexenoic acid, 3-hexenoic acid, 2-acetyl-5-hydroxy-3-oxo-4-hexenoic acid (dehydracetic acid), 5-hexenoic acid, 2,4-hexadienoic acid (sorbic acid), 1-hexen-1-ylboronic acid, 5-hexynoic acid, shikimic acid, 6-heptenoic acid, 2,6-heptadienoic acid, 6-heptynoic acid, 2-octenoic acid, trans-1-octen-1-ylboronic acid, fumaric acid, bromo-fumaric acid, chloro-fumaric acid, dihydroxyfumaric acid, dimethylfumic acid, fumaric acid monoethyl ester, mesaconic acid, maleic acid, bromomaleic acid, chloromaleic acid, dichloromaleic acid, dihydroxymaleic acid, dibromomaleic acid, maleamic acid, citraconic acid, glutaconic acid, 3-methyl-2-pentenedioic acid, itaconic acid, muconic acid, mucobromic acid, mucochloric acid, acetylenedicarboxylic acid, styrylacetic acid, 3-butene-1,1-dicarboxylic acid, aconitic acid, 3-butene-1,2,3-tricarboxylic acid, 2-acrylamidoglycolic acid, 2-acryamido-2-methyl-1-propanesulfonic acid, 3-allyloxy-2-hydroxy-1-propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, 2-propene-1-sulfonic acid, 4-styrene sulfonic acid, 2-sulfoethyl methacrylate, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate, 3-vinylbenzoic acid, 4-vinylbenzonic acid, tran-2-(4-chlorophenyl)vinylboronic acid, tran-2-(4-fluorophenyl)vinylboronic acid, tran-2-(4-methylphenyl)vinylboronic acid, 2-vinylphenylboronic acid, 4-vinylphenylboronic acid, vinylphosphonic acid, vinylsulfonic acid, monoacryloxyethyl phosphate, cinnamic acid, α-acetamidocinnamic acid, α-bromocinnamic acid, 2-bromocinnamic acid, 3-bromocinnamic acid, 4-bromocinnamic acid, 3-bromo-4-fluorocinnamic acid, 4-bromo-2-fluorocinnamic acid, 5-bromo-2-fluorocinnamic acid, 2-carboxycinnamic acid, 2-chlorocinnamic acid, 3 -chlorocinnamic acid (cis), 4-chlorocinnamic acid (trans), 4-chloro-2-fluorocinnamic acid, trans-2-chloro-6-fluorocinnamic acid, trans-2,4-dichlorocinnamic acid, 3,4-dichlorocinnamic acid, trans-2,4-difluorocinnamic acid, trans-2,5-difluorocinnamic acid, trans-2,6-difluorocinnamic acid, trans-3,4-difluorocinnamic acid, trans-3,5-difluorocinnamic acid, 2,3-dimethoxycinnamic acid, 2,4-dimethoxycinnamic acid, 2,5-dimethoxycinnamic acid, 3,4-dimethoxycinnamic acid, 3,5-dimethoxycinnamic acid (trans), 3,5-dimethoxy-4-hydroxycinnamic acid, 4,5-dimethoxy-2-nitrocinnamic acid, α-ethyl-cis-cinnamic acid, α-fluorocinnamic acid, 2-fluorocinnamic acid, trans-3-fluorocinnamic acid, 4-fluorocinnamic acid, 4-formylcinnamic acid, 2-hydroxycinnamic acid, 3-hydroxycinnamic acid, 4-hydroxycinnamic acid, 3-hydroxy-4-methoxy-trans-cinnamic acid, 4-hydroxy-3-methoxy-trans-cinnamic acid, 4-isopropyl-trans-cinnamic acid, 2-methoxycinnamic acid, 3-methoxycinnamic acid (trans), 4-methoxycinnamic acid (trans), α-methylcinnamic acid, 3,4-(methylenedioxy)cinnamic acid, 4-methyl-3-nitrocinnamic acid, α-methyl-3-nitrocinnamic acid, α-methyl-4-nitrocinnamic acid, 2-nitrocinnamic acid, 3-nitrocinnamic acid (trans), 4-nitrocinnamic-acid (trans), 2,3,4,5,6-pentafluorocinnamic acid, 2-(trifluoromethyl)cinnamic acid, 3-(trifluoromethyl)cinnamic acid, trans-4-(trifluoromethyl)cinnamic acid, 2,3,4-trifluorocinnamic acid, 3,4,5-trifluorocinnamic acid, 3,4,5-trimethoxycinnamic acid (trans), 2,4,6-trimethylcinnamic acid (cis), and their corresponding anhydride or salt.
[0046] The cationic monomers are also preferably water soluble, although cationic monomers that display little or no water solubility can also be used. Cationic monomers can be positively charged, or they can bear groups such as amines that are partially protonated in water to form ammonium groups. Preferred cationic monomers include unsaturated amines and unsaturated ammonium salts. Unsaturated cationic monomers may contain one, or more than one, carbon-carbon double bond.
[0047] Examples of suitable cationic monomers include allylamine, N-allylaniline, allylcyclohexylamine, allylcyclopentylamine, allylmethylamine, N-acryloyltris(hydroxymethyl)methylamine, N-tert-amyl-1,1-dimethylallylamine, N-tert-amyl-1,1-dimethylpropargylamine, diallylamine, 3,3′-diallyl-oxy-diisopropanolamine, 1,1-diethylpropargylamine, N-ethyl-2-methylallylamine, 3-ethynylaniline, 4-ethynylaniline, 1-ethynylcyclohexylamine, geranylamine, N-methylallylamine, propargyamine, vinylamine, 4-vinylaniline, 3-(acrylamidopropyl)trimethylammonium salt, (2-(acryloyloxy)ethyl](4-benzoylbenzyl)dimethylammonium salt, [2-(acryloyloxy)ethyl] trimethylammonium salt, 2-aminoethyl methacrylate hydrochloride, N-(3-aminopropyl)methacrylamide hydrochloride, diallyldimethylammonium salt, 2-(N,N-dimethylamino)ethyl acrylate dimethyl salt, 2-(N,N-dimethylamino)ethyl acrylate methyl salt, 2-(N,N-dimethylamino)ethyl methacrylate dimethyl salt, 2-(N,N-dimethylamino)ethyl methacrylate methyl salt, ethyl-3-amino-3-ethoxyacrylate hydrochloride, 4-ethynylpyridine hydrochloride, [3-(methacrylamido)propyl]trimethylammonium salt, [2-(methacryloyloxy)ethyl]trimethylammonium salt, propargyamine chloride, vinylbenzyltrimethylammonium salt, and N-2-vinyl-pyrrolidinone.
[0048] The molar ratio of anionic monomer to cationic monomer in the cross-linked copolymer is preferably in the range of from 95:5 to 5:95, more preferably in the range of from 1:9 to 1:1, and the ratio of anionic monomer to cationic monomer is particularly preferably in the range of 1:9 to 1:3. By changing the mole ratio of anionic monomer to cationic monomer, the performance of the composite membrane can be changed.
[0049] The anionic/cationic nature of the copolymer can also be obtained by using zwitterionic monomers to form the cross-linked copolymer. The zwitterionic monomers can bear both anionic and cationic groups, or they can bear groups that can be ionized to form negative and positive charges. Preferred zwitterionic monomers include unsaturated zwitterions or precursors thereof that can be readily converted to zwitterions. Unsaturated zwitterionic monomers may include one, or more than one, carbon-carbon double bond.
[0050] Examples of suitable zwitterionic monomers include 4-imidazoleacrylic acid, 4-aminocinnamic acid hydrochloride, 4-(dimethylamino)cinnamic acid, 1-(3-sulfopropyl)-2-vinylpyridinium hydroxide inner salt, 3-sulfopropyldimethyl-3-methacrylamidopropylammonium inner salt, and 5-amino-1,3-cyclohexadiene-1-carboxylic acid hydrochloride. Zwitterionic monomers can also be used in conjunction with an anionic monomer, with a cationic monomer, or with both.
[0051] While it is preferable that the support member be hydrophilic to facilitate the introduction of a charged cross-linked copolymer and to facilitate the passage of polar fluids, hydrophobic support members can also be utilized in certain situations, such as when a surfactant or a mixed solvent containing water and an organic solvent which wets the support are utilized. Materials that are suitable for making the hydrophilic support member include, for example, cellulose acetate (CA), poly(vinylidene floride) (PVDF), polysulfone (PS), polyethersulfone (PES), Nylon 6, poly(ethylene-co-vinyl alcohol) (EVAL) and poly(acrylonitrile) (PAN). Materials that are suitable for making a hydrophobic support member include, for example, polypropylene, poly(tetrafluoroethylene) (PTFE) and poly(vinylchloride) (PVC).
[0052] The average pore diameter of the support member can vary widely, but it preferably ranges from about 0.001 to about 20 microns, more preferably from about 0.002 to about 5 microns and particularly from about 0.005 to about 1 microns.
[0053] The porosity of the support member, which is a measure of the pore volume (also referred to as the void volume), is preferably from about 25 to about 95%, more preferably from about 45 to about 85% and particularly from about 0.60 to about 80%. Composite membranes prepared with support members having less than 25% porosity have very low fluxes, while support members with a porosity higher than 95% usually do not provide enough mechanical strength to anchor the copolymer. The porosity of the support member can be determined from the value of the bulk density of the porous support member and the density of polymer forming the support member, according to ASTM D-792.
[0054] The support member used in the invention is preferably either a symmetric porous membrane or an asymmetric porous membrane. Microfiltration membranes are suitable as symmetric porous membranes, and they preferably have a thickness of from about 10 to 300 microns, more preferably from about 20 to 150 microns and particularly from 50 to 120 microns. The thinner the support member, the higher the flux.
[0055] The asymmetric support member normally has a multi-layered nature, with a dense layer having smaller pores being supported on a backing layer that has larger pores. Ultrafiltration membranes are suitable for use as asymmetric support members. While these support members are described as having “layers”, they only comprise a single continuous phase of a single polymer. The layers represent regions having different physical characteristics but the same chemical characteristics. The asymmetric membranes can also comprise non-woven materials (e.g. polyester) which act as mechanical strengthening materials. For asymmetric support members, the thickness of each layer is not critical, as long as sufficient mechanical rigidity is retained. With asymmetric support members, the cross-linked copolymer is substantially anchored within the pores of the dense layer, as shown in the SEM image of FIG. 1 . Therefore, in asymmetric composite membranes, the void volume of the support member is not fully occupied by the cross-linked copolymer. In FIG. 1 (a), the dense layer of a PAN asymmetric support member is completely filled with a cross-linked copolymer. FIG. 1 ( b ) shows that while the more porous layer of the asymmetric PAN-based membrane has some dispersed copolymer within its pores, most of the space is free of copolymer. When the composite membrane of the invention is prepared with an asymmetric support member, the thickness of the dense layer determines the flux of the membranes. It has been observed that asymmetrically filled composite membranes, such as those obtained using ultrafiltration membranes as the support member, lead to pervaporation membranes having higher fluxes.
[0056] Asymmetric composite membranes can also be prepared with symmetric support members, by asymmetrically filling the pores of the support member with the cross-linked copolymer. Such asymmetric composite membranes can be prepared by initiating the cross-linking reaction on a single side of the support member, thus obtaining unequal distribution of cross-linked copolymer through the thickness of the support member. It is also possible to obtain an asymmetrically filled membrane by only partially filling the support member with the solution containing the monomers and initiator.
[0057] The composite membranes of the present invention can be prepared by polymerizing and cross-linking a mixture of negatively charged (anionic) and positively charged (cationic) monomers into the pores of porous symmetric (microfiltration) or asymmetric (ultrafiltration) support members.
[0058] Preferably, the composite membranes are prepared through water-based chemical reactions, although the composite membranes can also be prepared using mixtures of water and organic solvents. Typically, a solution comprising both positively and negatively charged monomers, a cross-linker and an initiator are introduced into the pores of a porous support member and anchored in place by polymerization within the pores using a free radical polymerization process.
[0059] Preferably, in situ polymerization and cross-linking occur simultaneously when preparing the composite materials. The function of cross-linking is to control and modulate conformation flexibility of the cross-linked copolymer. The cross-linkers used in the invention preferably have at least two unsaturated groups to form a three dimensional cross-linked structure with the cationic/anionic copolymer. While water soluble cross-linking agents are preferred, cross-linking agents that display little or no solubility in water can also be used. Examples of suitable cross-linkers include 3-(acryloyloxy)-2-hydroxypropyl methacrylate, allyl diglycol carbonate, bis(2-methacryloxyethyl) phosphate, 2,2 -bis(4-methacryloxyphenyl)propane, 2,2-bis[4-(2-acryloxyethoxy)phenyl]propane, 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane, 1,4-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, cinnamyl methacrylate, 2-cinnamoyloxyethyl acrylate, trans-1,4-cyclohexanediol dimethacrylate, 1,10-decanediol dimethacrylate, N,N′-diallylacrylamide, diallyl carbonate, diallyl maleate, diallyl phthalate, diallyl pyrocarbonate, diallyl succinate, 1,3-diallylurea, 1,4-diacryloylpiperazine, diethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol divinyl ether, 2,2-dimethylpropanediol dimethacrylate, dipropylene glycol dimethacrylate, divinyl glycol, divinyl sebacate, divinylbenzene, N,N′-ethylene bisacrylamide, ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, N,N′-hexamethylenebisacrylamide, N,N′-methylenebismethacrylamide, 1,9-nonanediol dimethacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, pentaerythritol triallyl ether, 1,5-pentanediol dimethacrylate, 1,4-phenylene diacrylate, tetraethylene glycol dimethacrylate, triallyl cyanurate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol divinyl ether, 1,1,1-trimethylolpropane diallyl ether, 1,1,1-trimethylolpropane triacrylate, and 1,1,1-trimethylolpropane trimethacrylate. Preferably, the amount of cross-linking agent is from 0.1% to 25%, more preferably from 0.5% to 20%, and particularly preferably from 1.0% to 15%, based on the total molar amount of monomers.
[0060] In situ polymerization of cationic/anionic monomers in the pores of the porous support member can be initiated by free radical polymerization procedures. Such free radical polymerization includes initiation of the polymerization by photo initiation, thermal initiation or redox initiation. The initiator used in this invention is preferably water soluble, and any water soluble thermal and/or photo initiator can be used. The amount of initiator used is generally from about 0.01% to about 3.0%, preferably from about 0.1% to about 2.5%, and particularly preferably from about 0.2% to about 2.0% of the amount of total monomers by weight.
[0061] The pore-filled membranes of this invention may be utilized in various configurations, such as plate-and-frame configuration, spiral wound configuration, and tubular or hollow fibre configuration.
[0062] The novel composite membranes of the invention may be particularly useful in pervaporation process for dehydration aqueous mixtures of organic solvents. It is also possible to utilize composite membranes of the invention to remove water from immiscible or partially miscible mixtures by pervaporation. In addition, the composite membranes may be particularly useful for separating azeotropes.
[0063] Examples of organic solvents that can be dehydrated by composite membranes of this invention include alcohols, glycols, weak acids, ethers, esters, ketones, aldehydes, amides, liquid hydrocarbons and their derivations, and aromatic hydracarbons. Said alcohols may include ethanol, propanol, i-propanol, n-butanol, i-butanol, t-butanol, amyl alcohols, and hexyl alcohols. Said glycols may include ethylene glycol, propylene glycol, butylene glycol or glycol ethers such as diethylene glycol, triethylene glycol, or triols, including glycerine. Said weak acids may include acetic acid, propionic acid, lactic acid, malonic acid, butyric acid, succinic acid, valeric acid, and caproic acid. Said esters may include methyl acetate, ethyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, n-amyl acetate, i-amyl acetate, methyl formate, ethyl formate, benzyl formate, methyl benzonate, ethylene glycol mono acetate, and propylene glycol monostearate. Said ethers may include tetrahydroforan, diethyl ether, dipropyl ether, diisopropyl ether, and ethyl propyl ether. Said ketones may include acetone, butanone, methyl ethyl ketone (MEK), 2-pentanone, 3-pentanone, methyl isobutyl ketone, 1,3-dioxolane, acetonylacetone, acetylacetone, and acetophenone. Said aldehydes may include formaldehyde, acetaldehyde, and propionaldehyde. Said amides may include N,N′-dimethylformamide, and N,N′-dimethylacetamide. Said liquid hydrocarbons may include heptane, hexane, cyclohexane, heptane, and octane. Said liquid hydrocarbons derivations may include dichloroethane, methylene dichloride, dichloropropane, ethylenediamine, diethylamine, isopropylamine, thiethylamine, acetonitrile, propionitrile, and butyronitrile. Said aromatic hydrocarbons may include benzene, toluene, ethylbenzene, and xylenes. Good results can be achieved when treating solvents having more than two carbons. Solvents having less than three carbons, such as methanol, ethanol, ethylene glycol, can still be dehydrated, but with a somewhat lower selectivity. Understandably, the organic solvents treated should be inert with respect to membranes of this invention.
[0064] Aqueous organic solutions treated by composite membranes of the invention may contain 1-99.9 wt. % water. It is more economical when mixtures containing less than 50 wt. % water are treated, and it is especially practical when mixtures are in azeotropic composition or containing less than 20 wt. % water.
[0065] Composite membranes of the invention can also be used to separate alcohol/non-polar or alcohol/polar mixtures. Suitable non-polar organic mixtures include 2,2,3-trimethylbutane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 2-methylpetane, 3-methylpetane, hexane, 2-methylhexane, 3-methylhexane, 2,2-dimethylhexane, 2,4-dimethylhexane, 2,5-dimethylhexane, 3,4-dimethylhexane, cyclohexane, heptane, 2-methylheptane, 3-methylheptane, 4-methylheptane, octane, benzene, ethylbenzene, toluene, and xylenes. Suitable alcohol/polar mixtures includes methanol/isopropanol, methanol/dimethyl carbonate (DMC), methanol/methyl tert-butyl ether (MTBE), and methanol/tert-amyl methyl ether (TAME).
[0066] In the pervaporation process of this invention, a solution to be treated is typically kept at 40° C.-120° C., for example at 80° C., and passed into contact with a composite membrane of the invention. Typically, the composite membrane of the invention retains both high flux and selectivity values at high operation temperatures. When the composite membrane is asymmetrically filled with the cross-linked copolymer, the side of the membrane having a larger amount of cross-linked copolymer is contacted with the solution. A pressure drop of about one atmosphere is commonly maintained across the composite membrane. Typically, the feed side of the composite membrane is kept at about atmospheric pressure and the permeate side is kept at a pressure of 0.1-60 mbar, preferably at a pressure of 2-20 mbar, and more preferably at a pressure of 10 mbar. The fluid retrieved on the permeate side of the composite membrane mostly comprises the polar component of the solution, and it also includes a small portion of the less polar component of the solution. Typically, the permeate contains 80-99.99 wt. % of the polar component. When the less polar solution component is an organic solvent that contains more than two carbons and the polar component is water, the permeate usually contains 95-99.99 wt. % water.
[0067] Composite membranes of the invention can be incorporated into reactors to remove water by-products. In some reactions, such as reversible reactions, the water that is produced decreases the reaction rate and inhibits the completion of the reaction. In order to drive the reaction to completion efficiently and economically, water has to be removed from the reaction vessel while the reaction is taking place. This can be achieved by combining a composite membrane of the invention with a reactor. By continuously removing water from the reactor with a composite membrane of the invention, the reaction rate can be increased and the reaction can be driven to completion.
EXAMPLES
[0068] The following examples are provided to illustrate the invention. It will be understood, however, that the specific details given in each example have been selected for purpose of illustration and are not to be construed as limiting the scope of the invention. Generally, the experiments were conducted under similar conditions unless noted.
[0069] In the specific examples that follow, the CA support member was obtained from Advantec MFS, Inc.; the CA Plus support member was obtained from GE Osmonics Inc.; the EVAL support member was obtained from 3M Company; the Nylon support member was obtained from Cole-Parmer company; the PAN support member was obtained from GMT membrantecknic Germany; and the PVDF support member is a microfiltration membrane obtained from Millpore Inc. The Irgacure 2959 photo initiator was obtained from Ciba speciality Chemicals Inc., and all other chemicals employed in the examples were obtained from the Aldrich Chemical Company.
[0070] A schematic diagram of a pervaporation apparatus used in the examples is shown in FIG. 2 . The feed solution temperature is controlled by a water bath and the feed solution is circulated to the surface of the membrane by use of a pump. The support membrane is placed and sealed on a porous aluminum support of a stainless steel pervaporation cell. The effective membrane area was 21.40 cm 2 . The pressure of the permeate side was kept below 5 mbar with a vacuum pump. The permeate was collected in a liquid nitrogen cold trap. Two parallel permeate lines were used to collect the permeate samples so that the pervaporation apparatus can operate continuously. The pervaporation apparatus was run for at least 1 hr to reach an equilibrium state before starting to collect permeate sample. Once sufficient permeate sample was collected, the sample line was switched to the parallel line to continue collecting sample, the collected permeate was warmed to room temperature, it was weighed and its composition was analyzed using a Varian 3800 Gas Chromatograph.
Example 1
[0071] This example illustrates the preparation of composite membranes of the invention using either a thermal- or a photo-initiated method.
[0000] Thermally-Initiated In Situ Polymerization:
[0072] In this example, the anionic monomer used was methacrylic acid, sodium salt (MAAS), the cationic monomer was diallyldimethyl ammonium chloride (DADMAC). The mole ratio of DADMAC/MAAS was 4:1. The cross-linker used was N,N′-methylenebisacrylamide (MBAA), the amount of MBAA used was 3% based on the total molar amount of monomers. Ammonium persulfate was used as the thermal initiator, its amount was 1.0% of the total weight of monomers. Mixing the above chemicals and diluting them to 50% monomers concentration, stirring the mixture for 0.5-2 hrs till all solids are dissolved in water. After filtration to remove any undissolved solid by filter paper, the mixture was ready to prepare the membrane.
[0073] A CA microfiltration membrane with a pore size of 0.8 μm and a porosity of 72% was used as support member. After immersed the CA support member into the prepared monomers solution for 2 to 10 minutes to fill pores with the solution, the wetted support member was sandwiched with two polyethylene films. Other films, such as polypropylene or polyester, can also be used to sandwich the wetted support member. After removing the excess solution by gentle application of a roller, the sandwiched membrane was put into an oven at 60° C., for between 0.5 to 1 hour, until the polymerization reaction finished.
[0000] Photo-Initiated In Situ Polymerization:
[0074] In this example, the monomers solution was prepared in the same procedure as in the thermal method except that the photo initiator Irgacure 2959 was used instead of a thermal initiator.
[0075] The same type of CA microfiltration membrane was used as support member. After wetted and sandwiched the support member, the sandwiched membrane was put into UV chamber for 0.5-2.0 hr to irradiate the reaction. The wavelength of the UV used was around 350 nm.
[0076] In each preparation procedure, after removing the two sandwich layers, unbound homopolymer was removed from membranes by exaction with distilled water until no further mass loss occurred. Then the membrane was dried in the air.
[0077] These two membranes were tested in pervaporation experiments with 92.0 wt. % IPA/water at 60° C. The thermal prepared membrane has a flux of 0.49 Kg/m 2 hr and the permeate contains 97.0 wt. % water; the flux of the photo prepared membrane is 0.47 Kg/m 2 hr and the water content in the permeate is 98.0 wt. %.
Example 2
[0078] This example illustrates the use of an asymmetric membrane as support member to prepare pervaporation membrane of this invention.
[0079] In this example, A PAN HV1,1/T ultrafiltration asymmetric membrane was used as support member, its mean pore size is 0.0246 microns as specified by the provider. The cationic monomer was [2-(methacryloxy)ethyl]trimethylammonium chloride (MAETAC), the anionic monomer was methacrylic acid (MAA). Their mole ratio was 4:1. MBAA was used as cross-linker, its amount was 3% of the total moles of monomers. Photo initiator Irgacure 2959 was taken, its amount was 0.5% of the total weight of monomers. The concentration of the monomers in the solution was 60 wt. %. The membrane was prepared in accordance with example 1 using the photo-initiated method.
[0080] When dealing with 89.2% IPA/water at 75° C. in pervaporation test, the membrane has a flux of 2.35 Kg/m 2 hr and the permeation water content is 97.0 wt. %.
Example 3
[0081] This example demonstrates the effect of anion/cation mole ratio on the performance of pore-filled membranes.
[0082] A series of membranes were prepared with different anion/cation mole ratio. The anionic and cationic monomers were MAA and 3-(acrylamidopropyl)trimethylammonium chloride (APTAC), respectively. Six anion/cation mole ratio, i.e., 0:100, 20:80, 40:60, 60:40, 80:20, 100:0, were used. The total concentration of the monomers in solution was 65 wt. %. All other conditions were the same as example 1 using the photo-initiated polymerization method.
[0083] These membrane were tested with 90.9 wt. % IPA/water and the results are shown in FIG. 3 . In the whole mixture range, anion/cation copolymer filled membranes have both higher flux and higher selectivity than MAA filled membranes. When the cation content in monomer solutions higher than 50 mol. %, the flux and selectivity of prepared membranes are higher than those of only anion or cation filled membranes.
Example 4
[0084] This example demonstrates the effect of anionic monomer on the performance of pore-filled membranes.
[0085] A series of membranes were made in this example with different anionic monomers while using APTAC as cationic comonomer. Used anionic monomers include acrylic acid (AA), MAA, MAAS, 2-acryamido-2-methyl-1-propanesulfonic acid (AMPS), 4-styrene sulfonic acid, sodium salt (SSAS). The blank example means the membrane was prepared only with APTAC anionic monomer, and there was no cationic monomer used. The mole ratio of cation/anion was 4:1, and their total concentration was 65 wt. %. The cross-linker was MBAA and the cross-linking degree was 5 mol. % of total monomers. All other preparation conditions were the same as described in example 1 using the photo-initiated method.
[0086] The pervaporation performance of this series membranes were tested with 91.6 wt. % IPA water at 60° C. The results are shown in FIG. 4 . By changing anionic monomers, the hydrophilicity of anionic/cationic copolymer changes, and thus the pervaporation performance of prepared membranes were changed.
Example 5
[0087] This example demonstrates the effect of cationic monomer on the performance of pore-filled membranes.
[0088] In this example, MAA was used as anionic monomer, while the cationic was APTAC, [2-(acryloyloxy)ethyl]trimethylammonium chloride (AETAC) and MAETAC respectively. Similar to example 4, the Blank membrane means the membrane prepared with only MAA anionic monomer. The support member was EVAL, which has a pore size of 0.28 μm and a porosity of 48%. All other preparation conditions were the same as in example 1 using the photo polymerization method except the total concentration of monomers was 65 wt. % and the amount of initiator was 0.5% of the total monomers weight.
[0089] FIG. 5 shows the pervaporation results of this series of membranes with 89.9 wt % IPA/water at 60° C. The performance of membranes was changed with different cationic monomers due to the change of the hydrophilicity of the copolymer. Combined this example with example 4, it can be concluded that cation/anion pore-filled membranes have a tunable pervaporation performance, and it is easy changed by changing the anion or cation in copolymers.
Example 6
[0090] In this example, different hydrophilic support members were used to show the effect of support members on the performance of cationic/anionic pore-filled membranes.
[0091] Two series of membranes were prepared. APTAC and MAA were used as cationic and anionic monomers in the first series of experiments. Their total concentration was 65 wt. % and their mole ratio was 4:1. Four support members, CA (0.2 μm), CA (0.8 μm), EVAL and PVDF, were used to prepare membranes. All other membrane fabrication conditions were the same as in example 1 using the photo-initiated method. Properties of four support members and the performance of prepared membranes with these support members at 60° C. are shown in Table 1. It can be seen that support members have a great influence on the performance of cationic/anionic pore-filled membranes. The larger the porosity of the support member, the higher the flux of the corresponding pore-filled pervaporation membrane.
TABLE 1 Performance of pore-filled membranes with different support members Pore C IPA size Porosity (wt. %) Flux Substrate (μm) (%) Feed Perm Kg/m 2 hr Selectivity CA 0.2 66 90.7 2.57 0.63 380 CA 0.8 72 90.6 1.94 0.68 508 EVAL 0.2 48 90.1 3.86 0.34 253 PVDF 0.22 56 91.6 6.01 0.47 157
[0092] In the second series of experiments, MAETAC and MAA (mole ratio 4:1) were used as cationic and anionic monomers, and their total concentration was 65 wt. %. Five support members, CA (0.2 μm), CA (0.8 μm), CA Plus, EVAL and PAN, were used to prepare membranes. Except that the amount of the initiator was 0.5 wt % of the total monomers weight, all other membrane fabrication conditions were the same as in example 1 using the photo-initiated method. Properties of these support members and the performance of corresponding prepared membranes are shown in Table 2. Among these membranes, the membrane prepared with PAN support member has the highest flux, and the membrane fabricated with CA support member of 0.8 μm pore size has the highest selectivity.
TABLE 2 Performance of pore-filled membranes with different support members Pore size Porosity T C IPA (wt. %) Flux Substrate (μm) (%) (° C.) Feed Perm Kg/m 2 hr Selectivity CA 0.2 66 60 91.0 3.08 0.41 318 CA 0.8 72 60 93.3 1.12 0.52 1240 CA Plus 0.22 50 60 90.3 2.09 0.39 436 EVAL 0.2 48 60 90.9 1.44 0.37 684 PAN 0.025 — 75 89.2 3.03 2.35 260
[0093] These two series of experiments show that the pervaporation performance of cationic/anionic copolymer pore-filled membrane is greatly affected by the support member. The larger the porosity of the support member, the higher the flux of the corresponding pore-filled pervaporation membrane. For PAN asymmetric support member, cationic/anionic copolymer were mainly anchored into the thin PAN layer, as shown in FIG. 1 , therefore, the corresponding membrane has extremely high flux.
Example 7
[0094] This example shows the effect of temperature on pervaporation performance of anion/cation pore-filled membrane.
[0095] A CA microfiltration membrane, which has a pore size of 0.2 μm and porosity of 66%, was used in this example. The anionic and cationic monomers used were MAA and APTAC respectively, their concentration was 65 wt. % and their mole ratio was 1:4. Other membrane preparation conditions were the same as in example 1 using the photo-initiated method.
[0096] The pervaporation characteristics of the prepared membrane was tested at different temperatures with 91.2 wt. % IPA/water, and the results are shown in FIG. 6 . The flux was increased sharply with the temperature, the flux at 70° C. are more than 2 times higher than that at 30° C. At the same time, the selectivity of the membrane only decreases a little. This means anionic/cationic copolymer membranes can have both higher flux and higher selectivity at higher operation temperature, which is an advantage of this invention.
Example 8
[0097] This example shows the effect of IPA feed concentrations on pervaporation performance of anion/cation pore-filled membrane.
[0098] A CA microfiltration membrane, which has a pore size of 0.2 μm and porosity of 66%, was used in this example. The anionic and cationic monomer used were AA and APTAC respectively, their concentration was 65 wt. % and their mole ratio was 1:9. The other membrane preparation conditions were the same as in Example 1 using the photo-initiated method.
[0099] The pervaporation characteristics of the prepared membrane were measured with different IPA/water concentrations at 60° C., and the results are shown in FIG. 7 . With the increase of IPA feed concentration, the flux decreases and the selectivity increases. At all the tested feed concentrations, the water content in the permeate was higher than 95 wt. %. After all the tests, the dimension of the membrane was changed by less than 2%, and the membrane still can be used to dehydrate organic solvents. However, many commercial membranes cannot be used after dealing with mixtures of higher water content.
Example 9
[0100] This example shows the performance of anionic/cationic pore-filled membranes when treating higher IPA feed concentrations.
[0101] A PAN HV1,1/T ultrafiltration asymmetric membrane was used as support member in this example. The anionic and cationic monomer used were MAA and MAETAC respectively, their concentration was 68 wt. % and their mole ratio was 1:4. The other membrane preparation conditions were the same as in Example 1 using the photo-initiated method.
[0102] The experimental results are listed in Table 3. It shows that the permeate IPA concentration of the membrane is still below 5 wt. % even when the feed IPA concentration is as high as 98.5%. In the mean time, the flux of the membrane is still relative high.
TABLE 3 Performance of membranes at higher IPA concentration at 80° C. IPA concentration (wt. %) Flux Feed Permeate (Kg/m 2 hr) 96.0 0.59 0.40 96.3 1.11 0.34 97.6 1.77 0.20 98.0 2.57 0.18 98.3 4.35 0.15
Example 10
[0103] In this example, the pervaporation performance of anionic/cationic pore-filled membranes is compared with those of several commercial available membranes, the tested system is IPA/water.
[0104] The membrane of this invention was prepared with PAN support member. The anionic and cationic monomers were MAA and MAETAC (mole ratio 1:4) respectively, and their concentration was 60 wt. %. The amount of initiator was 0.5 wt. % of the total monomers weight, all other fabrication conditions were the same as in example 1 using the photo irradiation method. GFT 2216 and Sulzer 1702w are two commercialized pervaporation membranes. The performance of these three membranes was tested, and the results are shown in Table 4. The results show that the flux of the membrane of this invention is at least 5.5 times higher than those of two commercialized membranes, while all membranes have similar selectivities.
TABLE 4 Performance comparison of different pervaporation membranes IPA Concentration T (wt. %) Flux Membrane (° C.) Feed Permeate (Kg/m 2 hr) GFT 2216 75 89.6 0.96 0.24 Sulzer 1702w 75 91.0 0.81 0.28 This invention 75 91.5 1.17 1.81
Example 11
[0105] In this example, the pervaporation performance of anionic/cationic pore-filled membranes is compared with those of several commercial available membranes with published performance data.
[0106] Three organic solvents system, Methyl ethyl ketone (MEK)/water, Acetone/water and IPA/water, were tested by pervaporation experiments. The anionic and cationic monomers used in this example were MAA and MAETAC (mole ratio 1:4) respectively, and their concentration was 65 wt. %. Except that the support member was EVAL, all other conditions were the same as in example 1 using the photo-initiated method. The performance of the membrane of this invention was measured and the comparison is shown in Table 5. In Table 5, data of membrane GFT 1 was from patent EP 0,381,477, data of membrane GFT 2 was published in patent U.S. Pat. No. 4,755,299. The results show that the performance of the cationic/anionic copolymer pore-filled membrane of this invention is superior to those two commercial membranes.
TABLE 5 Performance comparison of different pervaporation membranes Feed water T content Flux Membrane Solvents (° C.) (%) (Kg/m 2 hr) Selectivity GFT 1 MEK 60 0.75 0.04 16 Present MEK 60 1.3 0.03 31800 invention GFT 1 Acetone 50 2.01 0.04 6 Present Acetone 50 1.20 0.05 1600 invention GFT 2 IPA 45 20 0.30 250 Present IPA 45 20 0.60 633 invention Note: Data of membrane GFT 1 was from patent EP 0,381,477, data of membrane GFT 2 was published in patent U.S. Pat. No. 4,755,299.
Example 12
[0107] In this example, an anionic/cationic pore-filled membrane is used for the pervaporation dehydration of ethanol/water mixture.
[0108] The membrane tested in example 10 was used in this example. The membrane was used to dehydration 92.1 wt. % ethanol at 70° C. It has a flux of 0.40 Kg/m 2 hr and the permeate has a water content of 79.0 wt. %.
Example 13
[0109] In this example, an anionic/cationic pore-filled membrane is used in the pervaporation dehydration of ethylene glycol (EG)/water mixture.
[0110] The anionic and cationic monomers used in this example were MAA and MAETAC (mole ratio 1:4) respectively, and their concentration was 65 wt. %. The support member was EVAL. Except the amount of initiator was 0.5 wt. % of the total monomers weight, all other conditions were the same as in example 1 using the photo-initiated method. The prepared membrane was used to dehydration 89.1 wt. % EG at 70° C. It has a flux of 0.55 Kg/m 2 hr and the permeate has a water content of 76.7 wt. %.
Example 14
[0111] In this example, an anionic/cationic pore filled membrane is used in the pervaporation dehydration of other organic solvents/water mixtures at 60° C.
[0112] The membrane in example 10 was used in this example. The experimental results are shown in Table 6. For organic solvents having more than two carbons, cationic/anionic copolymer pore-filled membranes have both high fluxes and high selectivities. For acetic acid, the membrane has high flux.
TABLE 6 Pervaporation dehydration of solvents by anionic/cationic pore-filled membrane Feed Permeate water water content content Flux Solvent (%) (%) (Kg/m 2 hr) Selectivity t-butanol 10.9 —* 0.64 >40000 MEK 9.2 99.94 2.06 14100 Acetic acid 11.4 43.4 2.78 6.0 Acetone 24.5 97.7 1.70 133 *no t-butanol was detected in the permeate.
Example 15
[0113] In this example, an anionic/cationic pore-filled membrane is used in the pervaporation separation of other methanol/organic solvent mixtures.
[0114] The anionic and cationic monomers used in this example were Itaconic acid (IA) and MAETAC (mole ratio 1:4), the support member was EVAL. Except the total monomers concentration was 55 wt. %, all other conditions were the same as in example 1 using the photo-initiated method. The prepared membrane was used to separate methanol/MTBE and methanol/toluene at 60° C., and the results are shown in Table 7. The results show that the pore-filled membrane has good permselectivity to methanol.
TABLE 7 Pervaporation separation of methanol/solvents by pore-filled membrane Permeate methanol Feed methanol content Flux Solvent content (%) (%) (g/m 2 hr) Selectivity MTBE 10.5 98.6 18.8 605 Toluene 11.0 98.0 54 396
Example 16
[0115] In this example, the scale-up of pore-filled membranes was investigated.
[0116] The anionic and cationic monomers used in this example were MAA and MAETAC (more ration 1:4) respectively, and their concentration was 60 wt. %. The amount of initiator was 0.5 wt % of total monomers weight. All other fabrication conditions were the same as in example 1 using the photo-initiated method. A 60 cm disk membrane was made by this method. Three random parts of the big disk membrane were cut and their performance was measured. The experimental results were shown in Table 8. It can be seen in Table 8 that these three parts have similar flux and selectivity, which demonstrate unequivocally that the 60 cm membrane is homogeneous. Therefore, there are no scale-up problems in making these anion/cation pore-filled membranes.
TABLE 8 Reproducibility of Pore-filled membranes IPA concentration T (wt. %) Flux Part (° C.) Feed permeate (Kg/m 2 hr) A 75 90.0 3.04 1.78 B 75 91.9 3.85 1.82 C 75 91.4 3.50 1.68
Example 17
[0117] Besides flux and selectivity, durability or stability is another important property of pervaporation membranes. The durability of anionic/cationic copolymer pore-filled membranes was measured in this example.
[0118] Anionic and cationic monomers used in this example were AA and APTAC (mole ratio 1:9) respectively, and their concentration was 60 wt. %. All other preparation conditions were the same as in example 1 using the photo-initiated method. After operated with 60° C. 91.5 wt. % IPA/water for 3 hrs, the flux of the membrane was 0.51 Kg/m 2 hr and the selectivity was 230. Subsequently, the membrane was immersed into 60° C. 91.5 wt. % IPA/water for 60 days. After 60 days, the membrane has a flux of 0.6 Kg/m 2 hr and the selectivity was 330. This means that the anion/cation pore-filled membranes have good stability, their performance even improves a little after 60 days in 60° C. 91.5 wt. % IPA/water.
Example 18
[0119] In this example, water/organic solvent mixture was used as monomer solvent to prepare cationic/anionic pore-filled membranes.
[0120] MAETAC and MAA were used as cationic and anionic monomers in this experiment. Their total concentration was 65 wt. % and their mole ratio was 4:1. Instead using water as monomer solvent, water/ethanol (60:40 by weight) mixture solvent was used. PAN HV1,1/T support member was used. All other membrane fabrication conditions are the same as in EXAMPLE 1 using a photo-initiated method. The performance of the membrane was tested at 75° C. with 91.5 wt. % IPA/water mixture. The flux of the membrane is 3.16 Kg/m2 hr, and the IPA concentration in the permeate is 3.5 wt. %.
[0121] Another membrane was prepared with water/DMF (N,N-dimethylformamide) (60:40 by weight) mixed solvent. Except changing ethanol to DMF, all other membrane preparation conditions were the same as above. The prepared membrane was used to dehydrate 93.1 wt. % IPA. It has a flux of 2.30 Kg/m2 hr, and the IPA permeate concentration is 2.5 wt. %.
Example 19
[0122] In this example, a polypropylene hydrophobic support member was used to prepare cationic/anionic pore-filled membranes.
[0123] Polypropylene hydrophobic support members were obtained from 3M Company. One support member PP4, has a porosity of 68.5%, and its pore size is 0.18 μm. The other support member PP5, has a porosity of 80.5%, and its pore size is 0.82 μm. The monomer solution prepared in EXAMPLE 10 with water/ethanol solvent was used in this example.
[0124] The performance of the membrane prepared with the PP4 support member was tested at 75° C. with 92.9 wt. % IPA/water mixture. The flux of the membrane was 0.56 Kg/m 2 hr, and the IPA concentration in the permeate was 7.0 wt. %.
[0125] The membrane prepared with the PP5 support member was tested at 75° C. with 93.6 wt. % IPA/water mixture. Its flux was 0.76 Kg/m 2 hr, and the IPA concentration in the permeate was 2.1 wt. %.
Example 20
[0126] In this example, the ethanol separation performance of a composite membrane is enhanced by using an anionic monomer (SSAS) and varying its ratio with respect to a cationic monomer (MAETAC).
[0127] A series of membranes were prepared by copolymerizing different mole ratios of the anionic monomer SSAS and cationic monomer MAETAC with the crosslinker methylbisacrylamide (MBAA). The mole ratios of SSAS/MAETAC used were 10:90, 20:80, 30:70, 40:60, 45:55 and 60:40, respectively. The total concentration of the monomers in solution was 55 wt. %, and the amount of initiator was 0.5 wt. % based on the total weight of monomers. A PAN HV 3T ultrafiltration asymmetric membrane, which has a mean pore size of 6.7 nm (as specified by the provider), was used as a support member. All other conditions were the same as in the photo-initiated polymerization method described in Example 1.
[0128] The prepared membranes were used to dehydrate a 95 wt. % ethanol 5 wt % water feed at 70° C. The results are shown in FIG. 8 . A maximum value in selectivity can be seen at around 40 mol % of SSAS. The flux reaches a minimum value between 40 mol % and 50 mol % SSAS.
Example 21
[0129] This example shows the dehydration performance of anionic/cationic pore-filled membranes with low ethylene glycol (EG) feed concentrations.
[0130] Membranes were prepared using a method similar to the the photo-initiated polymerization method described in Example 1. SSAS and MAETAC were used as anionic and cationic monomers, respectively, in a mole ratio of 4:6, and a total concentration in solution of 55 wt. %. The crosslinking degree was 5 mol. % of total monomers, and the amount of initiator was 0.5 wt. % of the total weight of monomers. A PAN HV 3T ultrafiltration asymmetric membrane was used as support member. All other conditions were the same as in Example 1.
[0131] The prepared membrane was used to dehydrate low concentration aqueous EG at 75° C. The results are shown in Table 9, and they demonstrate that the membrane has a very high flux and reasonable separation when the feed EG concentration is lower than 50 wt. %.
TABLE 9 Dehydration of low concentration EG at 75° C. EG Conc. (wt. %) Flux Feed Permeate Selectivity (Kg/m 2 hr) 11.9 0.47 28 10.3 25.4 2.90 12 7.7 34.4 4.33 12 5.0 55.7 8.73 13 3.0
Example 22
[0132] This example describes the performance of large diameter membrane discs for use in a pilot plant.
[0133] Membranes were prepared using a method similar to the photo-initiated polymerization method described in Example 1. AMAA and APTAC were used as anionic and cationic monomers, respectively, in a mole ratio of 1:4. Their total concentration in monomer solution was 60 wt. %. The crosslinking degree was 3.5 mol. % of total monomers, and the amount of initiator was 0.5 wt. % of the total monomers weight. Large 65 cm diameter PAN HV 1,1/T ultrafiltration asymmetric membranes were used as support members. All other conditions were the same as in Example 1.
[0134] Large 65 cm diameter defect-free pore-filled membranes were easy to prepare with this formulation. The prepared membranes had fluxes of 1.55 Kg/m 2 hr and the permeate IPA concentration was 1.33 wt. % when treating 89.7 wt. % IPA feed solution at 75° C. Compared with membranes prepared with other monomers, MAA/APTAC pore-filled membranes were easy to mount on modules in the dry state without forming cracks.
[0135] All publications, patents and patent applications cited in this specification are herein incorporated by reference as if each individual publication, patent or patent application were specifically and individually indicated to be incorporated by reference. The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention.
[0136] Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is readily apparent to those of ordinary skill in the art in light of the teachings of this invention that certain changes and modifications may be made thereto without departing from the spirit or scope of the appended claims.
[0137] It must be noted that as used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural reference unless the context clearly dictates otherwise. Unless defined otherwise all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. | 4y
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TECHNICAL FIELD
The invention relates to frost-proof valves for exterior use.
BACKGROUND
A prior art frost-proof valve is shown in DE 202 19 008, the entire disclosed content of which is hereby included by reference for the purpose of disclosure. In this prior-art frost-proof exterior-wall valve, frost resistance is achieved by ventilating the interior of the valve device via a ventilation valve after the main valve has been closed. The ventilation valve of the prior-art valve device is a spring-loaded valve, which closes due to the internal pressure of the valve device when the main valve is open, and with decreasing internal pressure is moved into the open position by a pressure spring, allowing air to access the valve interior and causing water contained therein to drain via the discharge opening.
This valve device can allow reliable frost-proof operation. However, the inventor has determined that it can be further improved.
For valve devices connected to the public water supply network in the area of potable water supply, it is of advantage, and in some countries even required by statutory regulations, for a backflow prevention valve to be present, which serves to prevent feeding contaminated water into the water supply network through the valve against its flow direction. Such backflow prevention valves are usually embodied as spring-loaded check valves. However, when balancing the spring force of such a backflow prevention valve and of the ventilation valve of the prior-art frost-proof exterior-wall valve, it can be a challenge to balance the spring forces to achieve both a reliable backflow prevention on the one hand and a reliable opening of the ventilation valve in the un-pressurized state on the other.
There exists a need to further develop this prior-art valve, so as to guarantee frost-proof exterior use and at the same time to allow coupling a backflow prevention valve with the valve device or integrating it into the valve device, without creating any adverse effects on functionality.
SUMMARY OF THE INVENTION
One aspect of the invention provides a valve device for frost-proof exterior use, comprising:
an inflow opening, a discharge opening, a connecting channel, which connects the inflow opening to the discharge opening, a main valve, which is embodied so that it unblocks the fluid connection through the connecting channel in an open operating position and blocks the fluid connection in a closed operating position, an actuating mechanism for actuating the main valve, and draining means to drain the valve device in the closed operating position, characterized in that the draining means comprises a bypass line, which connects a first connecting channel section to a second connecting channel section.
The valve device according to one embodiment of the invention eliminates the need for two spring-activated valves within the valve device and thus allows both a reliable ventilation of the connecting channel in the blocked state as well as safe backflow prevention. The bypass line enables a ventilation flow between the connecting channel sections, which creates the pressure conditions for a complete draining/ventilation of the connecting channel in the frost-endangered region.
Surprisingly, it has been shown that the valve device according to one embodiment of the invention offers excellent reliability even in the case of a hose pipe connected to the discharge opening of the valve device or any other connected device that can generate a pressurized state in the valve device. For example, in practical application a first end of a hose may be connected to the discharge opening of the valve device while the second end of the hose is equipped with a shut-off device. In this case, a pressurized state can be maintained in the hose and the valve device, irrespective of whether the main valve of the valve device is open or closed, by closing or throttling the shut-off device at the second end of the hose.
In such cases, the valve device according to one embodiment of the invention prevents any undesired discharges of liquid via the draining means resulting from the external pressurization.
A further development according to one embodiment of the invention provides safety against such a liquid discharge by applying to both sides of the bypass line the pressure that prevails in the interior of the connecting channel or in a hose pipe connected thereto. In this manner pressure in effect in the valve device is prevented from leading to a fluid discharge from the valve device, since the draining means via the bypass line forms a closed cycle with respect to the environment of the valve device.
In this it is especially preferred for the second connecting channel section in the installed position of the valve device to be situated above, with respect to the direction of gravity, the first connecting channel section. Consequently, the hydrostatic force acting upon the aperture of the bypass line that opens into the first connecting channel section is lower than the force acting upon the aperture of the bypass line that opens into the second connecting channel section. As a result, an air flow can develop from the discharge opening to the second connecting channel section, from there through the bypass line, and via the bypass line into the first connecting channel section, facilitating effective ventilation of the connecting channel.
It is also advantageous, for the bypass line to connect a first connecting channel section to a ventilation space, which in turn is connected to the second connecting channel section. This ventilation space provides an air reservoir that leads to more uniform ventilation flow and consequently to a more uniform flow of draining fluid.
In particular, the bypass line is preferably formed in a section of the housing wall of the valve device and, in the installed position of the valve device, the bypass line extends at least partially downwardly along the direction of gravity from the ventilation space towards the discharge opening. This eliminates the risk of liquid accumulating in the ventilation space and/or in the bypass line.
In some situations it is preferred for the bypass line to connect the first and second connecting channel section for all positions of the actuating mechanism. For example, the bypass line may connect the connecting channel sections via continuous ventilation channels without any valves or other devices contained therein.
In some situations it is preferred for the draining means to comprise a ventilation valve in the bypass line. Such a ventilation valve can be used to securely close the bypass line, either manually or by means of application of spring force or pressure, making it possible in certain operating positions to reliably prevent a flow from passing through the bypass line.
In its open position, the ventilation valve allows ambient air access into the connecting channel for the purpose of draining the fluid from the connecting channel, while in a closed position it prevents any flow of air or liquid through the bypass line. This facilitates reliable ventilation on the one hand and prevents any undesirable discharge of water from the valve device—when this is not intended—on the other hand.
In embodiments which comprise a ventilation valve, it is particularly preferred for the ventilation valve to comprise a valve seat and a valve body. In a first position of an actuating mechanism on a first travel track the valve body is pressed onto the valve seat and in a second position of the actuating mechanism on the first travel track the valve body is lifted off the valve seat. In this manner, the ventilation valve is actuated directly by the movement of the actuating mechanism along the first travel track and is moved to defined positions for ventilation or for preventing liquid discharge from the interior.
Another significant further development of the valve device according to one embodiment of the invention is that the actuating means is configured such that the draining means for draining the valve device is opened and closed by moving the actuating mechanism along the first travel track whereas the main valve is opened and closed by moving the actuating mechanism along a second travel track.
This further development according to this embodiment of the invention falls back on a special—only partially autonomous—actuation of the draining means and does not require a spring-actuated automatic actuation of the draining means. This further development offers the advantage that the manual actuation of the draining means may be handled using the same actuating means that also serve in opening and closing the main valve. In this, two different travel tracks—one for opening the main valve and one for draining the valve device—offer the user a safe and easy-to-understand actuation of the valve device according to this embodiment of the invention. Moreover, moving the actuating means along two separate travel tracks realizes a particularly simple and robust design of the valve device, which further increases operational reliability and durability.
In the context of this embodiment of the invention, the first travel track is to be understood as a rotary, translatory, or in other manner directed movement of the actuating mechanism or of a part of the actuating mechanism. Analogously, the second travel track is to be understood as a rotary, translatory, or other-directed movement of the actuating mechanism or of the same above-mentioned part of the actuating mechanism. According to this embodiment of the invention, the first and second travel tracks possess different orientations, however movements can be performed along both travel tracks in one direction and in the direction opposite thereto, in order to perform an opening movement and a closing movement by moving in opposite directions along the same travel track.
A particularly favourable configuration of the valve device according to one embodiment of the invention comprises the above-described ventilation valve and the above-described actuating means for moving the actuating mechanism along first and second travel tracks. This allows the first travel track to serve for the actuation of the ventilation valve while the second travel track serves in actuating the main valve. This facilitates a reliable and for a user easy-to-understand actuation of the ventilation valve and the main valve by operating a single actuating mechanism. The ventilation valve preferably is actuated directly by moving the actuating mechanism along the first travel track.
In an especially preferred embodiment the second travel track is a rotary travel track and the first travel track is a translatory travel track oriented axially relative to the second travel track. This offers the user an intuitive operation of the invention's valve device, namely by performing the actual opening and closing of the main valve using a customary rotary motion and the opening and closing of the draining means using an axial translatory motion.
It is also preferred in some embodiments of the invention for the actuating mechanism to comprise a single actuating element moveable along the two travel tracks. Such an actuating element can for example be a turning knob, pull or push button, or a swivelling lever.
It is also preferred in some embodiments of the invention for the draining means to have a ventilation opening, which allows access of ambient air into the connecting channel for the purpose of draining the liquid from the connecting channel, preferably via the discharge opening. This allows a reliable ventilation of the interior of the valve device.
It is also preferred in some embodiments of the invention for the valve device to comprise a guiding mechanism to guide the actuating mechanism along the first and second travel tracks. Such a guiding mechanism can be provided in the form of a swivel or rotational axle, a sliding track, or similar, and is particularly preferred, since it aids in ruling out operator error by allowing only movements of the actuating mechanism along one of the guided directions. In this way one can reliably guarantee a predetermined direction of movement and a predetermined sequence of movement, which can serve to cycle through definite functional states of the valve device according to a predetermined sequence.
In such embodiments it is especially preferred for the guiding mechanism to guide the actuating mechanism from a first closed position, in which the main valve is closed and the draining means is in a drain position, along a first direction on the first travel track into a second position, in which the main valve is closed and the draining means is in a non-drain position in a first actuating phase. In a second actuating phase the guiding mechanism guides the actuating mechanism along a first direction on the second travel track into a third, open position, in which the main valve is open and the draining means are in a non-drain position. In this way, starting from a closed position of the main valve, one at first brings the draining means into a position where no draining can take place, e.g. the ventilation valve is closed, and subsequently in a second actuating phase the main valve is opened, whereby the draining means remain in the previously set position, e.g. the ventilation valve remains closed. This reliably prevents liquid from penetrating along the draining means in the open position of the main valve, i.e. escaping to the surroundings via the ventilation valve.
It is further preferred for the guiding mechanism, in a third actuating phase, to guide the actuating mechanism from the third, open position along a second direction on the second travel track—opposite to the movement of the second actuating phase—back to the second position, and in a fourth actuating phase to guide the actuating mechanism along a second direction on the first travel track—opposite to the movement of the first actuating phase—back to the first position. In this way, when a user intuitively operates the actuating mechanism in the opposite order and direction than before, he arrives at the original closed state of the main valve and achieves draining of the interior of the valve device.
It is further preferred for the actuating means to comprise a connecting-link guide. A connecting-link guide is especially suitable for a safe, dependable and cost-effective embodiment of the guiding means for the actuating means and can provide a large number of travel tracks.
In this embodiment, it is particularly preferred for the connecting-link guide to comprise at least one pin, which is connected to a housing section of the valve device or is connected to an actuating button of the actuating means, and a guide-pin track to guide the pin, which accordingly is embodied at the actuating button of the actuating means or at the housing of the valve device. Such a type of connecting-link guide is favourably suitable for the purposes of the valve device according to some embodiments of the invention and can be arranged in a space-saving manner in the region of the actuating mechanism.
In some embodiments of the invention the main valve preferably comprises a sliding valve, and in particular a rotary slide valve.
This further development is based on the realization that a certain discharge of water from the discharge opening or outlet is unavoidable in frost-proof valves and consequently other ways must be found to rule out maloperation. This is achieved by providing a completely different feel to the user in the actuation of the valve device. The configuration of the main valve as sliding valve imparts to the user that in a precisely defined lock position the valve will be closed and even additional force will not close it further. In this way one can prevent the user from attempting to operate the valve device with unacceptably high force.
It is particularly preferred for the main valve to comprise rotary slide valve. This configuration is particularly advantageous for the design of the valve devices according to some embodiments of the invention, since it allows a simple and reliable transfer of the actuating forces from the actuating mechanism to the main valve and allows realization of the customary rotary movement as the second travel track.
Moreover, the valve device according to some embodiments of the invention offers the advantage that with a sliding valve the user will not be able to exert excessive force to press the sealing faces together. A sliding valve is fundamentally characterized in that the flow aperture(s) are closed by executing a shear motion between the sealing body and the flow aperture(s), which is typically a sliding or rotating movement perpendicular to the flow direction. Consequently the sealing faces are never moved vertically toward each other and a greater actuating force does not result in a greater contact pressure between the sealing faces. This prevents damage to the sealing faces as a result of such an operating error.
Details and the advantages of the design of the main valve will be apparent from the description for claim 1 and the prior art embodiment shown in DE 20 2005 008 464.
In some embodiments of the invention, it is particularly preferred for the main valve to comprise a first valve element with at least one flow aperture and a second valve element that is rotatable about an axis and possesses at least one eccentric sealing face, which seals the flow aperture(s) of the first valve element in the closed operating position. This configuration allows a robust design and reliable sealing of the first valve of the valve device.
In such embodiments, it is particularly preferred for the first valve element and the second valve element to be separated by the same axial distance from each other in the open and the closed operating positions. This simplifies as far as possible the motion of the first and second valve elements relative to each other and achieves a robust design of the valve device.
In some embodiments, it is particularly advantageous for the first valve element to be embodied as a disk with two eccentric openings. The two eccentric openings provide an adequate flow area through the first valve element, whereby the openings are still of sufficient size to be insensitive to dirt accumulation and calcification. In such embodiments, the second valve element preferably comprises two sealing faces, which are arranged eccentrically, corresponding to the openings in the first valve element. These openings preferably are offset by 180° relative to each other and each extends over an angular range of approximately 90°.
It is particularly preferred if the main valve possesses at least one valve element of a ceramic material, preferably two valve elements of a ceramic material. Ceramic materials are especially well suited for the valve device according to some embodiments of the invention because they allow virtually wear-free operation and the forces occurring in a sliding valve are of appropriate levels for ceramic materials, thus allowing reliable operation over the lifetime of the valve device without requiring any maintenance procedures for the main valve.
It is further preferred in some embodiments of the invention if the actuating mechanism has to be turned by approximately 90° from the first operating position to reach the second operating position. In this way the user of the valve device receives unambiguous visual and tactile feedback that the open or closed operating position has been reached. This configuration is especially advantageous in cases where the actuating mechanism is embodied as swivelling lever or rotary handle.
The valve device according to some embodiments of the invention is preferably designed for horizontal installation into an exterior wall. This configuration is particularly advantageous for the valve device according to some embodiments of the invention if ventilation is realized for the most part by discharging water from the discharge opening and as a result the advantages provided by the invention can play a particularly important role.
It is further preferred that the actuating mechanism comprises a manually actuatable handle element, which acts together with a connecting rod that extends through part of the connecting channel, in order to transfer the motion along the first travel track to the main valve. This allows performing manual actuation in an exterior frost-prone region and arranging the main valve in the interior frost-proof region, which increases frost-resistance even further. Moreover, one attains a slender and robust design.
Another further development according to one embodiment of the invention is characterized by a first backflow prevention device arranged between the inflow opening and the main valve, to prevent polluted water from leaking from the valve device via the inflow opening. This configuration is advantageous for application of the valve device according to some embodiments of the invention in public water supply networks in order to meet regulations for fittings in such supply networks and to prevent water in the valve device from reaching the water supply in the event of excess pressure in the valve device.
A preferred embodiment will be described with the help of the enclosed figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an exploded view of a valve device according to a preferred embodiment of the invention.
FIG. 2 shows a side view of a longitudinal section of the valve device of FIG. 1 in a closed position with open ventilation valve.
FIG. 3 shows a longitudinal section of a detail of the exterior section of the valve device of FIG. 1 with the ventilation valve open.
FIG. 4 shows a side view of a longitudinal section of the exterior section of the valve device of FIG. 1 with the ventilation valve closed.
FIG. 5 shows a side view of a longitudinal section of the exterior section of a valve device according to a second embodiment of the invention.
DESCRIPTION
As shown in FIGS. 1 and 2 , the valve device according to the preferred embodiment of the invention comprises an exterior section 1 and an interior section 2 .
Arranged in the exterior section 1 are a discharge opening 20 , an actuating mechanism 50 , as well as a connecting channel 30 with exterior connecting channel sections 31 - 33 .
Arranged in the interior section 2 are an inflow opening 10 , a main valve 40 , as well as lower connecting channel sections 34 - 36 of the connecting channel 30 .
In the installed position, the interior section 2 is arranged in a wall or interior of a building while the exterior section 1 is arranged outside of the wall in the exterior where it is exposed to ambient temperatures. In the installed position, the discharge opening 20 faces downward along the direction of gravity.
FIG. 2 shows the valve device with its main valve 40 closed. The main valve 40 comprises a first valve element 41 , which is embodied as ceramic disk and possesses two eccentric bores 41 a,b . The main valve 40 also comprises a second valve element 42 , with a cross section in the shape of two triangles, which are in contact by their points and are shaped as semicircles on the sides opposite to these points. The triangular surfaces of the second valve element 42 form two valve sealing faces 42 a,b , which are dimensioned so that they can seal first and second openings in the first valve element 41 .
In its closed position, the main valve 40 prevents water from the inflow opening 10 from reaching the connecting channel 30 , by rotating the first valve element 41 relative to the second valve element 42 in such a manner that the two eccentric bores 41 a,b come to rest upon the two valve sealing faces 42 a,b of the second valve element and are sealed by them.
Turning the first valve element 41 by 90° with respect to the longitudinal axis of the valve device causes the two eccentric bores 41 a,b to become aligned with two corresponding openings in the second valve element 42 , so that water can flow from the inflow opening, through the valve device, to the discharge opening.
For this, the water enters the valve device in the horizontal direction via the inflow opening 10 . It then passes a check valve 80 arranged downstream of the inflow opening. The check valve 80 comprises a valve seat 81 , into which a valve body 82 is pressed by means of a pressure spring 83 . The water pressure exerts a force counteracting the pressure spring 83 upon the valve body surface 84 and thus lifts the valve body 82 from the valve seat 81 , which allows the inflow of water.
The water then flows in the direction of the main valve 40 as indicated by arrow B.
The second valve element 42 is connected rotationally rigidly to a coupling element 51 , which in turn is connected rotationally rigidly by means of a key and slot connection to a first end of a short actuating rod 52 . At its other end, the short actuating rod 52 is hexagonal in cross-section and is connected rotationally rigidly by means of a hexagon socket sleeve 53 to a long actuating rod 54 , which also possess a hexagonal cross-section.
At its other end, the long actuating rod is attached, by means of an adapter element 55 , rotationally rigidly but axially moveably to a valve sleeve 56 , which in turn is connected rotationally rigidly to an actuating knob 57 . In this way, a torque applied to the actuating knob 57 can be transferred to the second valve element 42 , in order to rotate the second valve element 42 accordingly and to move the main valve 40 from the closed operating position to the open operating position, and in reverse.
The actuating knob 57 together with the valve sleeve 56 is axially movable relative to the remaining components of the valve device. The valve sleeve 56 is secured against being pulled out of the valve device in the direction of the actuating knob by a sleeve nut 58 with an outside thread, which is screwed into a corresponding inside thread in a wall section 122 of the housing of the valve device.
The main valve 40 is arranged in a pipe section 35 , which is screwed to a pipe section 33 , 34 . The short and long actuating rods 52 , 54 extend through the pipe section 33 , 34 and connect the main valve 40 to the actuating knob 57 situated at a pipe end.
The pipe section 35 and the pipe section 33 , 34 are connected to each other by means of an adapter sleeve 60 , by screwing the pipe sections 35 and 33 , 34 with their respective inside threads onto a corresponding outside thread of the adapter sleeve 60 . The adapter sleeve 60 interacts with a stop piece 61 , which is pushed rotationally rigidly onto the hexagonal section of the short actuating rod 52 by means of a hexagon socket, and which comprises two arms 61 a,b extending radially. The arms 61 a,b interact with end stops 62 and 63 of the adapter sleeve 60 and in this manner limit the rotating angle of the short actuating rod 52 , and consequently of the entire actuating mechanism, to 90°.
The stop element 61 is oriented relative to the second valve element 42 in such a way so that—together with a corresponding orientation of the adapter sleeve 60 relative to the first valve element 41 —the main valve 40 is closed in the end stop position shown in FIGS. 1 and 2 and is open in the other end stop position reachable by rotating the actuating rod by 90°.
Arranged between the actuating knob 57 and the pipe section 32 is a ventilation valve 70 that serves in ventilating the interior of the valve device. The design and function of the ventilation valve 70 will be described with the help of FIGS. 3 and 4 .
The ventilation valve 70 comprises a valve seat 71 and a valve body 72 . The valve body 72 is integrally formed with the valve sleeve 56 . The valve seat 71 of the ventilation valve 70 is formed in the adapter element 55 , which is inserted in the housing wall of the valve device and sealed by means of two O-rings. The adapter element 55 contains bores 75 , 76 , which provide fluid communication between the ventilation valve 70 and the connecting channel section 32 .
A ventilation space 100 is situated between actuating knob 57 and the ventilation valve 70 and is sealed near the actuating knob by means of two O-rings 101 , 102 . A bypass channel 110 leads from the ventilation space 100 diagonally downward into the connecting channel section 31 in proximity of the discharge opening 20 .
In this way, air can flow from the connecting channel section 31 to the connecting channel section 32 via a continuous bypass line, formed by the bypass channel 110 , the ventilation space 100 , and the bores 75 , 76 .
A pressure spring 73 is supported on an annular shoulder of the housing wall and presses the valve sleeve 56 and the valve body 72 , including the actuating knob 57 fastened thereto, outward.
As illustrated in FIG. 1 , a radially arranged guide pin 120 is attached to the valve sleeve 56 and is guided in a guide-pin track 121 in a fixed wall section 122 of the valve device. The guide-pin track 121 allows the actuating knob 57 , with the valve sleeve attached thereto, to be moved axially inward from a starting position, in which the main valve 40 is closed and the ventilation valve 70 is enabled, in the direction of the ventilation valve 70 , whereby it forces the ventilation valve 70 to close by means of contact faces. When the ventilation valve 70 is in its closed position, the guide-pin track 121 allows the actuating knob 57 to be rotated by 90°. This rotation is transferred via the valve sleeve 56 to the adapter element 55 and further via the actuating rods 54 , 52 to the valve body 42 , which consequently is rotated into its open position.
When the actuating knob is rotated back by 90°, the spring element 73 automatically pushes the actuating knob and the valve body 72 back outward into the starting position. Thus, this allows water to drain from the interior of the valve device, since air can penetrate from the discharge opening 20 into the upper region of the valve device via the bypass line, which at the same time allows the residual water to drain from the valve device through the discharge opening 20 .
However, if some pressure remains in the valve device, for example as a result of pressure in a connected hose, then this internal pressure will also be applied in the ventilation space 100 via the bypass line. Consequently, ventilation of the interior of the valve device does not take place, nor is it possible for liquid to penetrate to the exterior via the ventilation valve 70 , if there is remaining internal pressure with the main valve 40 closed. This reliably prevents liquid from being discharged unintentionally through the ventilation valve 70 .
FIG. 5 shows a valve device according to a second embodiment of the invention. This embodiment does not contain a ventilation valve and thus foregoes a forced opening by axial displacement (in particular pushing) of the actuating button.
The variant of the valve device illustrated in FIG. 5 also exhibits a actuating knob 157 , which is connected rotationally rigid to a long actuating rod 154 via an adapter element 155 . The adapter element 155 contains ventilation channels 175 - 177 , which connect a bypass channel 210 , extending from the proximity of a discharge opening 120 diagonally upward to a ventilation space 200 , to a channel section above the orifice of the bypass channel 210 . This ensures a permanently open connection between the lower channel section 131 and the upper channel section 132 via the bypass channel 210 , the ventilation space 200 , and the ventilation channels 175 - 177 , guaranteeing a reliable ventilation of the interior of the valve device when the actuating knob 157 is moved from the open position to the closed position.
The actuating knob 157 in the embodiment shown in FIG. 5 is not axially movable but only can be rotated by an angle of 90° about the longitudinal axis of the exterior-wall valve. A connecting-link guide for control of the actuating knob 157 is no longer required in the embodiment shown in FIG. 5 . | 4y
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