Source: http://www.google.com/patents/US5752539?dq=6,373,753
Timestamp: 2015-05-28 12:47:50
Document Index: 697136768

Matched Legal Cases: ['art.\n13', 'art 119', 'art 117', 'art 121', 'art 117', 'art 117', 'art 117']

Patent US5752539 - Two flow control means using partially solidified plug - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsFiltering apparatus includes two or more passages (2) acting in parallel, each having an extended filter (12) which passes through inlet and outlet ports (48, 49), flowable preferably sealed by solidified plugs of the flowable substance such as a polymer being filtered. The flow of such substance to...http://www.google.com/patents/US5752539?utm_source=gb-gplus-sharePatent US5752539 - Two flow control means using partially solidified plugAdvanced Patent SearchPublication numberUS5752539 APublication typeGrantApplication numberUS 08/376,496Publication dateMay 19, 1998Filing dateMar 23, 1995Priority dateNov 16, 1990Fee statusLapsedAlso published asCA2055562A1, DE69124396D1, DE69124396T2, EP0557376A1, EP0557376B1, US5632902, WO1992008599A2, WO1992008599A3Publication number08376496, 376496, US 5752539 A, US 5752539A, US-A-5752539, US5752539 A, US5752539AInventorsPeter G. KalmanOriginal AssigneeKalman; Peter G.Export CitationBiBTeX, EndNote, RefManPatent Citations (19), Referenced by (6), Classifications (23), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetTwo flow control means using partially solidified plug
US 5752539 AAbstract
Filtering apparatus includes two or more passages (2) acting in parallel, each having an extended filter (12) which passes through inlet and outlet ports (48, 49), flowable preferably sealed by solidified plugs of the flowable substance such as a polymer being filtered. The flow of such substance to one passage can be terminated so as to permit filter advance under conditions of zero pressure drop, whilst flow through the other passage continues. Filter advance can be assisted by extrusion of a sealing plug in the outlet port under the pressure of such substance from the other passage which is still filtering. In additional or alternative mode, flow into a passage is terminated and a secondary outlet (20, 21) in that passage is opened. This creates a counterflow under the pressure of substance from the other passage, which cleans the filter. The secondary outlet can be sealed by a plug which is extruded during counterflow. An alternative valve for the secondary outlet, which can also be used in a diverter valve for controlling the input of substance to the two passages, has a side passage (26) in which is formed a plug of solidified substance, and piston (27) for pushing the plug into the flow substance.
1. Flow control apparatus for selectively permitting or limiting a flow of fluid through a conduit of a given cross section, comprising a side passage extending laterally of and communicating with the conduit, the side passage being sized and adapted to contain therein an at least partially solidified valve plug formed from a flowable substance which valve plug is capable of at least partially closing the conduit cross section, actuating means for urging the valve plug into the conduit so as to limit fluid flow therethrough, and thermal control means associated with the side passage for bringing about at least partial solidification of the valve plug prior to its introduction into the conduit, said thermal control means including coolant means adjacent the side passage which coolant means form said valve plug in the side passage.
2. Flow control apparatus as claimed in claim 1, in which fluid flowing from the conduit into the side passage is formed therein into said valve plug.
3. Flow control means as claimed in claim 1, wherein the thermal control means have in addition cooling means associated with the conduit to assist in maintaining the valve plug.
4. Flow control means as claimed in claim 3, wherein the thermal control means associated with the conduit includes heating means to cause or assist the dispersal of the valve plug when desired.
5. Flow control means as claimed in claim 1, wherein the means for urging the plug into the conduit includes a piston in the side passage.
6. Flow control means as claimed in claim 5, wherein the piston is provided with a thermally conducting extension which projects into such substance being formed into a valve plug in the side passage to assist in the cooling of the substance.
7. Flow control apparatus as claimed in claim 1, wherein a second side passage extends from the conduit laterally of and communicating with such conduit, the second side passage being adapted to contain therein an at least partially solidified valve plug there being actuating means for urging the valve plug from the second side passage into the conduit so as to limit fluid flow therethrough whereby the conduit can be alternately closed by valve plugs from the two side passages, said thermal control means including coolant means surrounding the second side passage.
8. The flow control apparatus as claimed in claim 7 in which valve plugs are formed in said two passages during overlapping time periods.
9. Flow control means as claimed in claim 1, in which the conduit and the side passage are joined by a connecting member of reduced thermal conductance.
10. Flow control means as claimed in claim 9, wherein the connecting part of reduced thermal conductance is of reduced thickness.
11. Flow control means as claimed in claim 1 wherein the flowable substance is a polymer.
12. Flow control means as claimed in claim 1 in which the conduit includes a flow channel in alignment with the side passage and an inflow passage into the flow channel and an outflow passage out of the flow channel, said inflow and outflow passages being spaced apart.
13. Flow control apparatus as claimed in claim 1 having a flow control body provided with coolant channels substantially surrounding the conduit.
14. Flow control means as claimed in claim 1 in which said conduit is tapered so that the valve plug is compressed as it is urged by said activating means into said conduit.
15. Flow control apparatus as claimed in claim 1 in which the valve plug has two ends and the end which enters the conduit first is softer than the remaining portion of the plug.
16. Flow control apparatus as claimed in claim 1 in which the valve plug is comprised of a polymer with impurities therein.
17. Flow control apparatus as claimed in claim 16 in which impurities include contaminants.
18. Flow control apparatus as claimed in claim 1 in which the valve plug is in a semi-solid state in the side passage prior to its being urged into the conduit.
19. Flow control apparatus as claimed in claim 1 in which the sealing plug is fully solid prior to being urged into the conduit.
20. Flow control apparatus as claimed in claim 1 in which the valve plug is cylindrical in shape.
21. Flow control apparatus as claimed in claim 1 in which the valve plug has a rectangular cross section.
22. Flow control apparatus as claimed in claim 1 in which the valve plug has an oval cross section.
23. Flow control apparatus as claimed in claim 1 having a bleed passageway for bleeding fluid from the conduit to the side passageway and in which the means for urging the plug into the conduit is fluid bleed through such passageway.
24. Flow control apparatus as claimed in claim 1 in which the side passage is cooled to create a first valve plug which is urged into the conduit and thereafter is cooled to create a second valve plug while the first valve plug is in the conduit.
25. Flow control apparatus as claimed in claim 1 in which the conduit has a recess opposite the side passage to support the valve plug upon its being urged into the conduit.
26. Flow control apparatus as claimed in claim 1 in which the conduit is cooled prior to the introduction of the valve plug into the conduit.
27. The flow control apparatus of claim 1 in which more than one side passage extends laterally of and communicates with said conduit.
28. The flow control apparatus of claim 1 in which the thermal control means includes in addition heating means for temporarily increasing the side passage temperature after valve plug formation to facilitate valve plug movement of the plug by reducing friction between the valve plug and side passage.
29. Flow control apparatus for selectively permitting or stopping a flow of fluid through a conduit, comprising a side passage extending laterally of and communicating with part of the conduit, the side passage being adapted to contain therein an at least partially solidified valve plug made from a flowable substance, actuating means for urging the valve plug into the conduit so as to stop fluid flow therethrough, and thermal control means associated with the conduit for selectively augmenting or reducing the degree of solidification of the valve plug, said flow control apparatus having a flow control body provided with heat transfer fluid flow channels substantially surrounding said part of the conduit therein into which a plug can be inserted, which channels are of a given cross section for circulating therein a heat transfer fluid.
30. Flow control apparatus for selectively permitting or limiting a flow of fluid through a conduit of suitable cross section, comprising a side passage extending laterally of and communicating with the conduit, said conduit being tapered, the side passage being sized and adapted to contain therein an at least partially solidified valve plug of flowable substance which plug is capable of at least partially closing the conduit cross section, actuating means for urging the valve plug into the conduit, which plug is compressed as so urged, so as to limit fluid flow through the conduit and thermal control means associated with the conduit for selectively augmenting or reducing the degree of solidification of the valve plug.
31. A method for permitting or stopping a flow of fluid through a conduit of selected cross section comprisingproviding a side passage extending laterally of and communicating with the conduit, the provided side passage being sized and adapted to contain therein an at least partially solidified valve plug of flowable substance which plug is capable of closing the conduit cross section; and providing actuating means for urging the valve plug into the conduit so as to stop fluid flow therethrough. 32. The method of claim 31 having the additional step of providing thermal control means associated with the conduit.
33. The method of claim 32 in which the thermal control means cools and heats.
34. The method of claim 32 in which the thermal control means cools.
35. The method of claim 31 having the additional step of providing thermal control means associated with the side passage.
36. The method of claim 35 in which the thermal control means cools and heats.
37. The method of claim 31 having the additional step of providing a thermal control means associated with the conduit and providing a thermal control means associated with the side passage.
38. The method of claim 31 in which the valve plugs are made from the fluid flowing through the conduit.
39. The method of claim 31 in which the fluid flowing through the conduit is a thermoplastic polymer.
40. Flow control apparatus for selectively permitting or stopping a flow of fluid through a conduit, comprising a side passage extending laterally of and communicating with the conduit, the side passage being adapted to contain therein an at least partially solidified valve plug made from a flowable substance, first thermal control means for causing at least partial solidification of such plug in the side passage, actuating means for urging the valve plug into the conduit so as to stop fluid flow therethrough, and second thermal control means associated with the conduit for selectively augmenting or reducing the degree of solidification of the valve plug, said second thermal control means having one or more flow channels substantially surrounding the part of the conduit therein into which said valve plug can be inserted, the flow channels being adapted to carry heat transfer fluids.
41. The flow control apparatus of claim 40 in which the second thermal control means includes heaters for heating valve plugs in the conduit.
This application is a continuation of U.S. patent application Ser. No. 08/120,872, filed Sep. 10, 1993, now abandoned, which is a divisional application of U.S. patent application Ser. No. 07/791,831, filed Nov. 13, 1991, now U.S. Pat. No. 5,632,902.
This specification relates primarily to filtering flowable substances including polymers and to valves for use therein. Nevertheless, aspects of the features disclosed will be of use in other contexts.
It has now been found that a number of new and inventive features can facilitate considerably the filtering of molten polymers, and particularly highly contaminated polymers. Thus, it has now been found that significant advantages can be obtained by operating two or more extended filter devices in parallel, in such a way that the outlets of the devices are in communication, so as to provide advantageous modes of operating the apparatus.
Thus, according to an invention disclosed herein, there is provided apparatus for filtering flowable substances or materials comprising first and second filtering passages each of which has:
Thus, there is provided apparatus for filtering fluid polymeric material comprising first and second filtering passages each of which has:
Thus viewed from a further aspect, according to an invention disclosed herein there is provided a process for filtering fluid polymeric material in apparatus comprising first and second filtering passages each of which has:
Viewed from a further aspect, according to an invention disclosed herein there is provided a process for filtering fluid polymeric material using apparatus comprising first and second filtering passages each of which has:
Viewed from a further aspect, according to an invention disclosed herein there is provided a process for filtering fluid polymeric material in apparatus comprising first and second filtering passages each of which has:
Thus, viewed from one aspect an invention disclosed herein provides a process for filtering fluid polymeric material in filtering apparatus comprising first and second filtering passages each of which has:
the process comprising the steps of selectively permitting flow of fluid polymeric material from a source thereof into the inlet of the first filtering passage whilst flow through the secondary outlet of the first passage is prevented by means of a sealing plug fonted therein, so as to filter the fluid polymeric material and pass it to the outlet; subsequently terminating the flow into the inlet of the first passage, whilst permitting flow into the inlet of the second passage, whose secondary outlet is provided with a sealing plug to prevent flow therethrough, so that polymeric material is filtered in the second passage and passed to the outlet; and carrying out a counterflow operation in the first passage which comprises the steps of
Once a plug has been used, another plug has to be formed in the side channel by cooling. In some cases the time necessary for this to be done may be excessive and until a fresh plug is formed a cycle of closing, opening and then closing the conduit again cannot be completed. In such cases, two or more side channels may be provided so that plugs are available in turn. Furthermore, cooling of the plug can be hastened if its cross section is elongated, i.e. if the plug has a long periphery for a given cross-sectional area. It may also be advantageous to provide the plug with an insert of good thermal conductivity, such as a metal pin, at least whilst it is in the side passage. This will assist in conducting heat away from the material forming the plug and increase the speed of solidification. Preferably, the insert does not project far into the conduit when the plug is moved, so as to avoid contact with large particulate contaminants in the conduit.
FIG. 1 represents a partly sectioned plan view of filtering apparatus;
FIG. 17a is a sectional view of the supporting members;
FIGS. 18 and 19 comprise a flow chart showing a series of program steps which correspond to successive computer operations;
FIG. 20 is an exploded sectional view of another embodiment of a flow control means including a valve housing, a pair of end plates and a partial sealing plug (but not showing any heating means);
FIG. 21 is an elevational view in the direction a--a of FIG. 20 without corner covers or heating means; and
FIG. 22 is a sectional end-on view showing heating means and one of four corner covers in an exploded form.
Referring to FIG. 1 filter body 1 contains two similar cylindrical filtering apertures disposed side by side, one of which is shown sectioned at 2. The filtering apertures contain conically hollowed-out end caps 3, 4, 5 and 6 which are bolted onto filter body 1 by means of bolts, one of which is shown at 7 and each end cap carries a perforated supporting disk, two of which are shown at 8 and 9, each provided with numerous, aligned perforations such as 10 and 11. Suitable filters 12 and 13 made, for example, from woven steel cloth pass between each pair of supporting disks.
Pistons 40 and 41 of the valve arrangement shown in FIGS. 5 and 6 can also be actuated by a common means as shown in FIGS. 16a-16d. Pistons 40a and 41a are both fastened to a frame 101 which is reciprocated by a double-acting pneumatic or hydraulic cylinder 102 which is fastened to valve body 44a by means of struts 102a. Clearly two valves such as 44a can also be utilized in place of valves 17 and 18 if faster repetition is required.
The valve arrangement shown in FIG. 1 is actuated by valve operating means 91 situated between the valves 17 and 18. An alternative arrangement in which the operating means are situated outside the valves is shown in FIGS. 15 and 15a. Valves 17a and 18a here have their pistons 97a and 97b oriented outward and fastened to frame 93 which is reciprocated by hydraulic cylinders 94 and 95 actuated in turn, the hydraulic cylinders being fastened to supporting struts 96 which are affixed to body 1 by means not shown.
FIGS. 7 and 8 represent an axial section taken in direction b--b of FIG. 1 and an end view seen from the direction c, with manifold 14 and valves 17 and 18 removed for clarity; purge valve 20 is shown as a revolved section. Body 1 is heated to processing temperature by heaters such as 46 and during filtering plastic flows through chamber 2 in the direction a; purge valve 20 is closed at that time. Filter 12 is cleaned in situ when required by closing the inflow of plastic from manifold 14 and by opening purge valve 20 in the manner disclosed above; during this phase plastic flows into chamber 2 in a direction opposite to a and, having transversed supporting disks 8 and 9 and filter 12, this flow leaves chamber 2 through channel 47 and valve 20, taking with it impurities collected by the filter opposite apertures such as 10. When sufficient cleaning has taken place purge valve 20 is closed once more and filtering recommences. It is found that after a number of such cleaning operations this process becomes progressively less efficient and eventually it becomes necessary to introduce a fresh filter part into chamber 2. This is carried out by first stopping the inflow of plastic into chamber 2 by closing valve 17, and, with purge valve 20 still closed, filter 12 is then moved in a manner generally described in GB-A-1181075 while sealing plugs, formed from the plastic being filtered, are maintained in ports 48 and 49 respectively where filter 12 enters and leaves filter body 1, by suitable thermal control means as disclosed e.g. in GBA-1181075; however since there is no plastic flow through filter 12 at that time this movement takes place substantially free of frictional resistance. Filter advance involves extrusion of the sealing plug in the outlet port 49. This outlet port is of greater cross-sectional area than the inlet port 48, so that there is a net force assisting extrusion, arising from the pressure of material in the passage which is connected to the outlet of the other passage. Preferably the entire contaminated portion of filter within the passage is replaced.
When the removal of comparatively small amounts of impurities suffices to clean the filters sufficiently then a short purge valve shown in FIG. 10 may be employed. When larger amounts of contaminants must be disposed of at a time this valve will be elongated as shown in FIGS. 14, 14a and 14b. Heaters 90a and cooling channels 90b are provided here in both sections of the valve so that the movement of the plug containing impurities can be swiftly arrested by recooling, the coolant channel near the constriction being particularly effective. The valve is provided with an adaptor section 91 securable to filter body 1 and at the other extremity the end of the constriction is shown at 90e.
The operation of a filtering system according to the invention under computer control involves detecting the pressure drop across the filters, valve cooling and polymer plug forming in the valves, timing of a suitable period to facilitate plug forming, closing the valves either by cooling alone or by accompanying mechanical traction, heating the valve bodies in order to open them, moving the filters so as to introduce fresh filter parts and controlling the filter lengths so introduced, keeping track of which filtering chamber is to be operated next and which actuator (in the case of double-acting actuators, which side of any actuator) is to be powered next and in what sequence so that the backflushing and filter renewal operations are fully controlled and properly coordinated. Filter movement may be controlled using a servo system of known art (U.S. Pat. No. 3,783,355) or by actuating an automatic cutter at the emerging filter end and detecting the position of the cut end by means of a photoelectric cell: in this way the filtering operation can be fully automated. In a similar way the semi-solid or solid plastic plug carrying the contaminants emerging from the purge valve can be severed and the position of the cut end can be likewise detected; where the contaminants are carried out in a largely fluid stream timing the open period of the valve will suffice. During purging through valve 20 contaminants carried in polypropylene the removal of as little as 215 grs. (less than half a pound) sufficed to adequately clean the filter area, depending somewhat on filter construction and the nature of the contaminants.
Referring to FIGS. 20-22 and initially particularly to FIG. 20, a further valve embodiment includes a valve body 116 having a flow channel consisting of an inflow part 119, a connecting part 117 of a preferably larger section into which an at least partially solidified plug can be inserted and an outflow part 121, valve body 116 being provided with coolant channels such as 124 surrounding connecting part 117. A fully or partially solidified plug 122 can be moved into connecting part 117 of the flow channel by means described earlier so as to close valve 115, Plug end 122a then enters a recess 125 in valve body 116 which both helps to support the plug and contains any impurities such as pebbles or swarf that may be in the flow channel when the valve is closed. The kind of valve geometry described provides a prolonged sealing length for the plug and, if the diameter of the connecting part 117 of the flow channel and therefore the plug diameter is made larger than that of inflow channel 119 and outflow channel 121 as shown, then the sealing action of the plug at these channels will be augmented.
If valve body 116 is precooled by means of a coolant circulated in channels such as 124 previously to the insertion of plug 122 then its sealing action will be further enhanced in that its periphery will come into contact with an already colder wall area so that thermal softening of plug 122 at its periphery will be reduced. Flow channel 117 may have a tapered geometry narrowing in the direction of plug travel so that the plug is squeezed as it is inserted. If instead of a circular cross section channel 117 and plug 122 are given an elongated rectangular or oval cross section then the plug will cool faster prior to its insertion and this makes faster cycling of the valve possible and thus permits the filtering of more contaminated material.
Turning to FIG. 22 it will be seen that coolant channels 124 terminate at corner chambers 133 which are sealed by means of four welded-on angle sections such as 128 and two end plates 130a and 130b shown in FIG. 20, the former having a central aperture which accomodates plug 122 and its housing. Coolant inflow and outflow passages, not shown, are provided which communicate with two diagonally situated corner chambers. Valve body 115 is also provided with heating means such as cartridge heaters 127 carried in projections of the valve body as shown in FIG. 22.
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