Abstract:
An apparatus and method for selectively heating and/or cooling a preselected compartment of a vehicle by providing a substantially overlapping heating circuit and cooling circuit able to be activated to control temperatures for extended periods without running the vehicle engine.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to thermal storage systems and more particularly to thermal storage systems for heating and cooling vehicle compartments and preheating vehicle engines.  
         BACKGROUND OF THE INVENTION  
         [0002]    Thermal storage units for vehicles such as trucks are known. Such known systems are disclosed in commonly assigned U.S. Pat. No. 5,277,038, which is incorporated by reference herein. In such known systems, a passenger compartment or sleeper compartment of a vehicle is cooled, (i.e. heat is removed), by circulating a coolant from a thermal storage system through a heat exchanger.  
           [0003]    Air is then passed over the heat exchanger, chilled, and directed to the desired location. The coolant is then recirculated back to the thermal storage unit to again bring down the temperature of the coolant and the cycle is repeated. Heating systems also are known whereby heated engine coolant is directed to a heater core, where air is blown over the heater core and the hot air is directed to a desired location.  
           [0004]    For example, in the trucking industry, heating and cooling systems are put to the added test of keeping a driver comfortable overnight while the driver rests in the sleeping compartment. The driver may be kept in relative comfort by applying either air conditioning or heating as needed. However, running such systems requires that the engine be left on, in an idling mode. In Europe, due to stringent environmental regulations, such idling is not permitted and a supplemental fuel fired heater is often operated to direct heat to a sleeping compartment. These heaters are used to a lesser extent in the United States.  
           [0005]    Further, conventional vehicle air conditioning and heating units are unable to store more than transient amounts of cooling or heating capability. The capability represents only a very small fraction of the capability required, for example, for the 8 hours a truck driver would be sleeping in his sleeping compartment. As such, during this period, the engine must be idled to operate the air conditioning and/or heating system.  
         SUMMARY OF THE INVENTION  
         [0006]    The invention provides an integrated heating and cooling system for cooling and/or heating a selected vehicle passenger compartment. The system comprises a heater for heating a heat exchange fluid with the heater powered independently from the vehicle engine. The heater is placed on line in the vehicle coolant system. Heat exchange fluid leaving the heater is directed through the circuit to a heat exchanger. The fluid then releases heat to the exchanger and heat, in the form of hot air, is directed to the desired compartment. A fluid controller selectively establishes and controls fluid circulation within the circuit. That is, fluid circulation proceeds from the heater to the heat exchanger and back from the heat exchanger to the heater. The integrated heating and cooling (IHC) system of the present invention further comprises a thermal storage reservoir for cooling heat exchange fluid. The reservoir is controllably connected for fluid communication with the heat exchanger circuit. The fluid controller selectively establishes fluid circulation of the cooled heat exchange fluid from the thermal storage reservoir to the heat exchanger and back. Again, in this cool mode the heat exchanger is cooled, thereby achieving air cooling with the air then directed to a selected passenger compartment. The IHC system is operable independently of the operation of the vehicle engine so that the system can run for prolonged periods without the engine idling.  
           [0007]    In a further embodiment, the present invention provides a thermal storage apparatus adapted to transfer heat to or from a fluid stream. The apparatus comprises a sealed housing filled with a plurality of individual sealed containers, which are arranged in rows within the housing, such that fluid flowing through the container contacts each of the containers in a heat exchange relationship. Each of the sealed containers houses an energy storage medium comprising water and a material capable of forming a clathrate hydrate with the water, along with small amounts of emulsifying agents or surfacants to promote mixing of the gas and the water, as disclosed in commonly assigned U.S. Pat. Nos. 5,056,588 and 5,277,038. Since most of the hydrate forming materials are gases, the term “gas hydrate” is generally used. However, certain low boiling point liquids, such as cyclopentane having a boiling point of 49° C. also form hydrates and fall into this general class. Typically, the phase change temperature for the gas hydrate in the sealed containers will be above 0° C. A movable agitator is positioned within each of the containers for providing mechanical movement within the medium. The containers are arranged to create continuous transverse interstices between individual containers, and extending across a plurality of rows of stacked containers. In one preferred embodiment an orifice plate is inserted between stacked rows of containers. The orifice plate has openings that align with the interstices to favorably effect fluid flow within the thermal storage housing.  
           [0008]    Still further, the present invention provides a method for regulating air temperature within a motorized vehicle. A cool circuit having a cool mode for decreasing the temperature within the vehicle is provided. In addition, a heat circuit having a heating mode substantially along the cooling circuit is provided for increasing the temperature within the vehicle. A controller selectively operates the cooling and heating modes as desired with or without running the vehicle engine.  
           [0009]    Further, a method of cooling and heating a compartment of a motorized vehicle is provided wherein a selectively controlled cold mode is achieved by circulating a heat exchange fluid through a circuit from a heat exchanger to a thermal storage reservoir. Heat is absorbed by the heat exchanger to produce cool air which is directed into a compartment to be cooled. In this mode, the heat exchange fluid absorbs heat and is directed back to the thermal storage reservoir to be cooled. In another mode of the invention, a selectively controlled heat mode is achieved by circulating a heat exchange fluid from a heater placed in the circuit to heat the exchange fluid. The heated exchange fluid is directed to the heat exchanger wherein heat is released therefrom to provide heating to air which is directed into a compartment to be heated. The exchange fluid is then directed back to the heater for reheating. Both the cold mode and heat modes use substantially the same circuit without running the vehicle motor. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    Some of the objects and advantageous of the present invention having been stated, others with become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:  
         [0011]    [0011]FIG. 1 schematically illustrates the placement of one preferred apparatus embodiment of the present invention mounted on the frame of a tractor trailer cab;  
         [0012]    [0012]FIG. 2 is a close-up of a partially broken away view of the apparatus shown in FIG. 1;  
         [0013]    [0013]FIG. 3 schematically illustrates a partially broken away view of the thermal storage reservoir portion of the apparatus shown in FIG. 1;  
         [0014]    [0014]FIG. 4 is a perspective that schematically illustrates the placement of the cooling cylinders within the thermal storage reservoir of FIG. 3;  
         [0015]    [0015]FIG. 5 is a sectional end view taken along line  5 - 5  of FIG. 4 showing a preferred cooling cylinder arrangement and a preferred arrangement of openings in an orifice plate positioned between stacked rows of cooling cylinders;  
         [0016]    [0016]FIG. 6 is a schematic illustration of a preferred embodiment of the heating and cooling system of the present invention; and  
         [0017]    [0017]FIG. 7 is a schematic illustration of an apparatus embodiment of the invention for enhancing charging of the thermal storage reservoir of the system of FIG. 6 and also illustrates flow of heated and/or cooled air directed into the sleeper compartment of a truck cab.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention, however, may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. For the purpose of this application it is understood that the term “vehicle” refers to any mechanized apparatus capable of accommodating a person during its operation.  
         [0019]    FIGS.  1 - 2  illustrate the positioning of the integrated heating and cooling (IHC) unit  10  onto the frame  12  of tractor trailer cab  14 . The unit  10  has first compartment  16  and thermal storage reservoir  18 . Thermal storage reservoir  18  has first and second sides  20 ,  22  having attached thereto first and second mounting brackets  24 ,  26 . The brackets have openings  28  spaced apart to match openings  30  in brackets  32 ,  34  which together receive bolts  36  which are fastened by securing washers  38  and nuts  40  into place.  
         [0020]    As shown in FIG. 2, thermal storage reservoir  18  in an exposed view reveals outlet  42  outlet tubing  44  and valve  46 . Valve  46  has outlet tubing  48  connected to a t-connector  50 . T-connector  50  connects tubing  52  to valve  54  and pump  56 . Pump outlet  58  is connected to tubing  60  which directs fluid flow out of first compartment through aperture  62 . Tubing  64  is shown directing a flow back to t-connector  66  to which is attached connecting tubing  68  and  70 . Connecting tubing  68  attaches to heater inlet  72  on heater  74 . Tubing  70  from t-connector  66  attaches to valve inlet  76  on valve  78 . Valve outlet  80  has tubing  82  directing fluid flow to inlet  84 .  
         [0021]    [0021]FIG. 3 illustrates the arrangement in thermal storage reservoir  18  of IHC unit  10  wherein a plurality of elongate tubular container  100  are arranged in fixed position. Housing  102  is shown covering insulating layer  104 . Thermal storage unit inlet  84  and outlet  42  are shown as well as vent  106  which may have an overflow detect switch (not shown) to deactivate the system if excess coolant enters the thermal storage reservoir.  
         [0022]    [0022]FIG. 4 shows further sectional view of second compartment of IHC unit  10  showing a cross sectional view of elongate tubular containers  100 . The container  110  shown in partially broken away view illustrates contents including solution  112  and agitators  114 . Any of various emulsifying, surfacants or wetting agents also can be included to promote mixing of the gas or gas hydrate and water. These can include sodium lauryl sulfate/dodecyl alcohol and polyglycerol oleate materials such as decaglycerol tetraoleate (available as CAPROL 10G-40 from Capital City Products) and perfluoroalkyl ethoxylate (ZONYL, Dupont), both of which have shown improved mixing and hydrate formation; sorbitan monoisostearate (available as CRILL 6 from Croda, Inc.) which appeared to have a more limited effect, and the like. Other surfacants to promote hydrate formation are set forth in U.S. Pat. No. 4,821,794 to Tsai et al. which is incorporated herein by reference.  
         [0023]    An orifice plate  116  is seen in FIGS. 4 and 5. The orifice plate  116  comprises a plurality of orifices sized such that, especially when a predetermined system pressure is supplied to the thermal storage reservoir inlet, there will be a positive pressure differential across each of the orifices. In one preferred embodiment, an orifice plate having 102 orifices each having a diameter of 0.073 inches produce a pressure drop of about 1 inch of water. It is understood that the system of the present invention can be modified to accommodate a pressure drop of from about 0.5 to about 15 inches of water.  
         [0024]    [0024]FIG. 5 is a cross sectional end view of the elongate tubular containers  100  shown in the thermal storage reservoir  18  of the IHC unit  10 . The openings or orifices  118  in the orifice plate  116  are shown to be aligned with a portion of the lengthwise, transverse interstices  119  formed between adjacent containers  100  which can be fixed in place, for example, by adhesive between adjacent containers in each horizontal row  120  and also between stacks of rows  120 . It is understood that the orifices  118  are preselectedly arranged so that fluid flow through the orifices  118  provides direct contact of fluid with each container  100  throughout the intersticial lengthwise space  119 . This is even true for the interstices  119  that do not have an apparent orifice  118  associated immediately therewith. Therefore, the positioning of the orifices  118  in the plate  116  promote enhanced uniformity of fluid contact with the exterior of the containers  100 .  
         [0025]    [0025]FIG. 6 is a schematic diagram showing one preferred embodiment of the present invention which is selectively activatable for heating or cooling modes. It is understood that the thermal storage reservoir houses the chilled containers of FIGS. 3 and 4 therein. An alternative cool storage media as will be well understood in the HVAC field also may be used. The system of the present invention is designed to run when the truck is not in operation, but is instead stationary with the driver sleeping in the sleeper compartment for an extended period with the engine off. In that mode, shown in FIG. 6, the cooling mode results in pump  602  being activated by control  604  to direct a flow of coolant from thermal storage reservoir  600 , through valve  606 , through line  608  and into pump  602 . Pump  602  activates the system sending the fluid flow along line  608  to heater core  610 . A blower  615  is then activated by control  604  to direct cool air through vent  612  and selectively into sleeper compartment  614  or passenger compartment  613 . The “spent” coolant fluid leaves heater core unit  616  and proceeds along line  618  back through valve  620  and into the thermal storage reservoir to complete the cooling cycle. The cycle does result in a cooling drain, however, and accordingly the thermal storage reservoir  600  is sufficiently sized and charged to deliver adequate cooling for an extended period. The pump may be controlled in conjunction with a thermostat or timer to insure that air of the desired temperature is directed to the preselected compartments. The pump may run intermittently or continuously as required to obtain the desired air temperature.  
         [0026]    In the novel heating mode of the present invention, heater  622  is activated by control  604  to heat cooling fluid flowing therethrough. Valve  620  is closed by control  604 . Heated fluid leaves heater  622  and proceeds through open valve  624  to pump  602 . Pump  602  delivers and directs the flow of the heated fluid coolant along line  608  to the heater core  616  wherein heat is released from the heated coolant through vent  612  and into sleeping compartment  614 . The spent coolant is returned to the heater along line  618 . Valve  620  is placed in the closed position as is valve  606  as a result of signals from control  604  such that no heated coolant proceeds into or out of the cold thermal storage reservoir  600 . In this way the “heat cycle” is repeated. Valves  626  and  628  which control flow to and from the engine compartment of the cab are also placed in a closed position through use of control  604 . However, if it is so desired, the engine can be warmed up with residual heat from the heated fluid. In this mode of operation, valves  626  and  628  are placed in an open position allowing the path, i.e., flow of the heat exchange fluid to extend from the heater  622  through the sleeper compartment  614  and into and from the engine  630 .  
         [0027]    It is important to note that this system does not compromise traditional engine-on cooling or heating through this evaporator/heater core system. For conventional cooling, valves  626 ,  628 ,  624 ,  606  and  620  will be closed and refrigerant from the truck air conditioning system will be evaporated in the evaporator enabling the blower to deliver cool air. For conventional heating, valves  624 ,  606  and  620  will be closed but valves  626  and  628  will be open, thereby allowing warm engine coolant, from the operating vehicle engine, to circulate through the heater core and enable the blower to deliver heated air.  
         [0028]    The system of the present invention further contemplates allowing for pre-heating the engine, and compartment if desired, following cold weather parking of the vehicle. A timer or manual start may be used such that the heater is activated at some time before the vehicle is required for use, typically 0.5 to 4 hours in advance. Valves  624 ,  626  and  628  are opened while the blower  615  is not operated to direct maximum heat to the engine. If cab warming is also desired, this can be accomplished simply by operating the blower.  
         [0029]    [0029]FIG. 7 is a cross-sectional schematic view showing the airflow through heater core  616  and evaporator  610  having an air space  611  disposed between them, whereby air is directed through the evaporator heater  610 , through the heater core  616  through duct  640  and out vent  612  into sleeper compartment  614 . One or both valves  650  and  652  are located in duct  640  at section  651  and are movable between an open position (not shown) and a closed position as illustrated to effect changing of cool storage reservoir as discussed in detail subsequently. The air flow valves  650  and  652  are controlled by controller  604 .  
         [0030]    The thermal storage unit of the present invention may be any unit capable of delivering the required cooling capacity. For truck sleepers, the cooling capacity is preferably from about 5,000 Btu to about 25,000 Btu and more preferably from about 8,000 Btu to about 15,000 Btu. It is contemplated that the reservoir preferably works to deliver the requisite cooling/heating, without running the vehicle engine, for periods of time up to at least about 8 hours; for example, the period of time during which the truck driver would sleep in his cab. It is contemplated the cooling capacity available would enable a driver to sleep comfortably in a parked vehicle with the engine off, in temperatures of about 110° F. for a period of up to several hours.  
         [0031]    The preferred thermal storage unit uses elongate canisters or containers containing a thermal energy storage medium disposed therein. The medium includes water and a gas capable of forming a clathrate hydrate, with the water. The phase change temperature for the gas hydrate is preferably above 0°. The canisters also contain agitators, preferably in the form of steel balls which assist in the hydrate formation. The process and canisters are well described in commonly assigned U.S. Pat. No. 4,922,998, the contents of which are incorporated by reference herein as if made a part of the present specification. It is understood that the thermal storage unit can have its cold recharged according to known methods such as those described in commonly assigned U.S. Pat. No. 5,277,038, which is incorporated by reference herein.  
         [0032]    As shown in FIG. 7, to charge the thermal storage unit, in a system with the evaporator and heater core separated by an air gap, a controller activates the air conditioning unit of the vehicle which cools the evaporator  610 , and also establishes circulation of heat exchanger fluid between the heat exchanger and the thermal storage unit. The controller also activates blower  615  so that air is cooled by contact with evaporator  610  and so that the cool air is then directed across the heat exchanger  616 . The fluid circulating through the heat exchanger is cooled because of the cool air contacting the heat exchanger. The cooled fluid is passed from the heat exchanger into the thermal storage unit for cooling thereof. The fluid is then circulated back to the heat exchanger for further cooling.  
         [0033]    The thermal storage reservoir of the present invention has new advantages however, which enable the efficiency of such unit to be increased over those presently known. In the past, it was believed that portions of the cooled fluid contained in the thermal storage reservoir  18  were not efficiently circulated within the reservoir. Such restricted, incomplete fluid circulation or “channelling”, resulted in non-uniform contact between the fluid and the containers within the thermal storage reservoir  18 . The present invention uses a thin plastic sheet or orifice plate  116  which extends across the entire cross section of the reservoir  18 . As already mentioned, the cooling canisters  100  contained within the reservoir  18  are affixed to one another such that their position within the reservoir  18  remains predictable and fixed throughout the life of the unit. The multiple stacked rows  120  of canisters  100  create lengthwise pathways  119  which do not impede fluid flow. These pathways, in the transverse direction, necessarily occur due to the curved shape of the canisters. See FIGS.  3 - 5 . The orifice plate  116  is inserted between stacked cylinder rows  120 . This eliminates the need for a header volume to distribute fluid to the orifice plate. Holes are formed in the orifice plate such that upon installation of the plate, the holes occur in the flow stream of the aforementioned flow pathways. In this way, any tendency of fluid within the unit to “channel” between the reservoir&#39;s inlet and outlet are frustrated due to the impedance and flow altering effect created by the orifice plate. The impedance enhances fluid distribution within the storage unit relating to a greater usage of available capacity. This results in a more uniform temperature being maintained in the system for longer periods thus increasing the overall efficiency of the system.  
         [0034]    The heater used in the heating mode of the present invention may be any heater run from a fuel source that may or may not be the same fuel that powers the vehicle engine. The heater selected must be capable of operating when the vehicle engine is not being operated. As mentioned above, the primary usefulness of the present invention is in affording heating and cooling systems to vehicles so as to obviate the need to run or idle an engine simply for the purposes of running the thermal cooling and heating system. One preferred heater is a fuel fired heater powered by diesel fuel provided by a separate line into the vehicle diesel tank. In this embodiment, while diesel fuel is still expended to run the system, extremely small amounts of diesel fuel are required as opposed to the relatively substantial amounts of fuel expended during overnight engine idling. Particularly preferred fuel fired heaters include the Webasto Thermo Top Z, or Webasto Thermo Top 90 (Webasto Thermosystems, Inc., Lapeer, Mich.).  
         [0035]    As shown in FIG. 6, at least one pump is placed on line to circulate fluid at a predetermined rate throughout the system. It is understood that the pump will be controlled by known control systems to activate either on a timed basis or in response to a thermostat such that the pump is activated when the air temperature within a cabin or the fluid temperature itself within the line measured at a certain point reaches a predetermined temperature. In this way, it is contemplated that in a preferred mode, the thermal control system of the present invention will be activated sporadically, or as needed, to further conserve truck fuel and increase overall energy efficiency of the system.  
         [0036]    The valves shown in FIG. 6 ( 606 ,  620 ,  624 ,  626 ,  628 ) are preferably poppet valves that are preferably pneumatically driven. It is understood that these valves are controlled by the control system to open and close depending upon the mode desired. One aspect of the present invention contemplates that when the cooling mode is desired, the appropriate valves are open and shut to completely shut down the access to the heating features  622 ,  630  of the system. That is, in the cool mode cool fluid leaves the thermal storage reservoir  600  and is routed to the heat exchanger  616  and then back to the thermal storage reservoir  600  without ever having access to the heater  622 . In this way, the fluid is kept as cold as possible for as long as possible. Similarly, in the heating cycle, heated fluid is routed directly from the heater  622  to the heat exchanger  616  and back to the heater  622  without every gaining access to the cool thermal storage reservoir  600 . In this way the fluid is kept as warm as possible for as long as possible. Therefore, the complementary positioning of the valves is critical to one preferred embodiment of the present invention to optimize thermal efficiency and enable the same piping (lines) and duct work to be used for both heating and cooling modes.  
         [0037]    The pump  602  preferably operates periodically during cooling and continuously while the unit is heating. Any excess heat in the heating loop that is not required to heat the vehicle compartment can be circulated to pre-heat the engine  630  through valves  626 ,  628  to keep the engine  630  at warmer than ambient temperatures for ease of starting during cold temperature operation resulting in less start-up pollution.  
         [0038]    The heater core  616  of the present invention may be commercially available as is known in the vehicle industry, or may be customized to better suit the needs of the present invention. In one preferred embodiment, as shown in FIG. 6, the heater/evaporator is a single unit, with the evaporator tubes  610  and heater tubes  616  mounted within the same fins. Here the evaporating refrigerant in the evaporator tubes  610  can conductively remove heat from the circulating coolant on charge, without the need to direct airflow over the unit. Such airflow induced by a blower  615  would be optional only. The preferred heater core evaporator of the present invention provides multiple functions. It can deliver heat or cold with the engine off. Further, it can deliver heat or cold with the engine on as well as work to cool charge the thermal storage reservoir. Conducting heat exchangers are commercially available (Behr of America), but may be customized by rearranging the placement of evaporator and heater tubes to maximize conductivity through the fins positioned therebetween.  
         [0039]    It is further understood, as shown in FIG. 7 that an air space  611  may occur between the heater core  616  and the evaporator  610 . In this embodiment, the heat exchanger has essentially no direct conductive heat transfer. In this FIG. 7 embodiment, airflow is required to charge the cool storage system, since there is no conductive path between the heat exchangers. The heater core is preferably oriented in close association with the duct work constructed to direct airflow to the sleeper cabin as shown in FIGS. 6 and 7. Finally, it is understood that the present invention contemplates the use of a blower to facilitate and augment, if necessary, whichever heat exchange arrangement (conductive or non-conductive exchange) is selected for the charging mode.  
         [0040]    Valves within the duct work as shown in FIG. 7 may be present to recirculate air in the most efficient means to the desired compartment. The valves  650 ,  652  are positioned to redirect airflow back to the evaporator heat core. It is to be understood that while both valve  650  and valve  652  could be present, only one is necessary in this system. The choice will depend on ease of integration into the vehicle&#39;s existing ducting. In this way, the sleeper compartment would not be thermally conditioned needlessly, thus conserving the efficiency of the system as air is directed only to the cabin areas inhabited by persons seeking thermal conditioning. Overnight, when the driver is in the sleeper compartment, valve  650  or  652  would be moved by a signal from a control  604  to a position that would allow airflow to the sleeper compartment.  
         [0041]    For example, in a preferred cooling mode during overnight sleep, air from sleeper compartment  614  is directed through duct  640 . Valve  652  is not in place for this example. Air flows through duct  640  and impacts evaporator  610  to cool heater core  616  of the heat exchange unit. Blower  615  is responsible for impelling the airflow from the cabin through the heat exchanger. The air leaves the exchanger and proceeds through duct  612  and cools compartment  614 . So long as valve  650  is in the open or “down” position, airflow circulation continues in this fashion. As the vehicle is under operation, the valve  650  is positioned into a “closed” or up position such that cool airflow from the heater core  616  cannot proceed into the duct  612 , but is forced back to the evaporator  610  to cool charge the thermal storage reservoir  600 .  
         [0042]    The blower and duct work associated with the present invention are constructed and positioned as would be readily understood to one skilled in the field of HVAC automotive construction. Further, it will be apparent to those skilled in the art that various changes and modifications can be substituted for those parts of the system described herein. For example, thermal storage media other than those specifically described herein can be advantageously used. Similarly, valves for controlling the flow of air to the first heat exchanger can be eliminated where desirable. Further, various substitutes for the valves and pumps, and/or additional valves and pumps, illustrated in the drawings can be employed in accordance with the invention. Moreover, a plurality of thermal storage reservoirs and/or thermal storage systems may be added to the vehicle in accordance with the invention.  
         [0043]    In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a descriptive sense only and not for the purposes of limitation. The invention has been described in considerable detail with specific reference to various preferred embodiments. It will be apparent, however, that various modifications and changes can be made within the spirit and scope of the invention as described in the foregoing specification and defined in the appended claims.