Abstract:
A gas supply system for store ejection from a vehicle comprises a receiver assembly, a compressor connected to the receiver assembly, and a gas storage vessel removably coupled to the receiver assembly, wherein the gas storage vessel is capable of receiving and storing pressurized gas from the compressor.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/028,436, filed on Feb. 13, 2008, the contents of which are herein incorporated by reference in their entirety. 
         [0002]    This application is a Continuation-In-Part of U.S. patent application Ser. No. 11/951,637, filed on Dec. 6, 2007, the disclosure of which is herein incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0003]    1. Technical Field 
         [0004]    The present disclosure relates to a gas supply system for pneumatic store ejection, and more particularly, to a self-contained, fast acting, high flow gas supply system for pneumatic store ejection that charges and stores the gas used for store ejection, and also utilizes a replaceable gas storage vessel/bottle that can be charged offline. 
         [0005]    2. Discussion of the Related Art 
         [0006]    A store is, for example, a bomb, missile, rocket and the like. Pressurized gas has been used to actuate store ejector mechanisms, such as, for example, pistons and suspension and release equipment on bomb racks, to permit forceful ejection of a store while a vehicle is in motion. It is to be understood that a vehicle may be an air, sea, or land vehicle, and the present disclosure will refer to aircraft for ease of description, but is not limited thereto. 
         [0007]    In conventional systems, aircraft may be equipped with an on-board compressor for compressing the gas used to actuate the store ejector mechanisms. However, in known systems, the compressor is not a part of a self-contained gas supply system. In addition, while an on-board compressor can recharge the gas-supply system, it is the only available means for charging or recharging the system. Recharging where the compressor is the only option may be a time consuming process, preventing quick mission turnaround. 
         [0008]    In many tactical situations, the military wants to fly a bombing mission, return to base, quickly re-load with more bombs, and fly again. However, known gas supply systems and store ejection mechanisms, such as pneumatically powered bomb racks, prevent quick mission turn-around of tactical aircraft. For example, in conventional systems, aircraft must wait until an on-board compressor, for compressing the gas used to actuate the store ejector mechanisms, recharges a gas-supply system. Existing gas supply systems rely only on an onboard recharging system, and due to compressor size, cannot recharge the system in a short time. In addition, existing systems require manual resetting of system components, which also increases turn-around time. 
         [0009]    Further, existing systems fail to perform equally well under varied environmental conditions, and may undesirably vary the time to release a store at, for example, different temperatures and air pressures. 
         [0010]    Accordingly, there is need for a gas supply system that can operate to desired specifications under all environmental conditions, and a gas supply system with a self-contained compressor design that also provides for automatic resetting of system components and high flow output from replaceable, refillable and reusable gas storage vessels. 
       SUMMARY OF THE INVENTION 
       [0011]    A gas supply system for store ejection from a vehicle, according to an embodiment of the present invention, comprises a receiver assembly, a compressor connected to the receiver assembly, and a gas storage vessel removably coupled to the receiver assembly, wherein the gas storage vessel is capable of receiving and storing pressurized gas from the compressor. 
         [0012]    The receiver assembly may include a port for connecting the compressor to the receiver assembly. The gas storage vessel can receive and store pressurized gas prior to being coupled to the receiver assembly. The gas storage vessel may be substantially empty of pressurized gas prior to being coupled to the receiver assembly. The gas storage vessel may be substantially full of pressurized gas prior to being coupled to the receiver assembly. The compressor may be operable only when the gas storage vessel is coupled to the receiver assembly. 
         [0013]    The receiver assembly may include a reservoir and the pressurized gas may be received and stored in the reservoir prior to being provided to the gas storage vessel. 
         [0014]    The gas supply system may further comprise an outlet port, wherein the pressurized gas is supplied from the gas storage vessel to a store ejection mechanism via the outlet port. 
         [0015]    A method for store ejection from a vehicle, in accordance with an embodiment of the present invention, comprises connecting a compressor to a receiver assembly, removably coupling a gas storage vessel to the receiver assembly, and flowing pressurized gas from the compressor to the gas storage vessel. 
         [0016]    The method may further comprise storing pressurized gas in the gas storage vessel prior to coupling the gas storage vessel to the receiver assembly and operating the compressor only after coupling the gas storage vessel to the receiver assembly. 
         [0017]    The receiver assembly may include a reservoir and the method may further comprise receiving and storing the pressurized gas in the reservoir prior to providing the pressurized gas to the gas storage vessel. 
         [0018]    The method may further comprise supplying the pressurized gas from the gas storage vessel to a store ejection mechanism. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Exemplary embodiments of the present invention will be described below in more detail, with reference to the accompanying drawings, of which: 
           [0020]      FIG. 1  is a perspective view of a gas supply system including a gas storage vessel and a receiver assembly, according to an embodiment of the present invention; 
           [0021]      FIG. 2  is a front view of the gas supply system, according to an embodiment of the present invention; 
           [0022]      FIG. 3  is a right-side view of the gas supply system, according to an embodiment of the present invention; 
           [0023]      FIG. 4  is a left side view of the gas supply system, according to an embodiment of the present invention; 
           [0024]      FIG. 5  is a left-side view of the gas supply system with an access panel removed to show a shaft and bell-crank, according to an embodiment of the present invention; 
           [0025]      FIG. 6  is a left-side view of the gas supply system with a receiver assembly housing removed to show a sequencing valve, according to an embodiment of the present invention; 
           [0026]      FIG. 7  is a top view of the gas supply system, according to an embodiment of the present invention; 
           [0027]      FIG. 8  is a top view of the gas supply system with an access panel removed to show a switch actuator rod, according to an embodiment of the present invention; 
           [0028]      FIG. 9  is a bottom view of the gas supply system, according to an embodiment of the present invention; 
           [0029]      FIG. 10  is a rear view of the gas supply system, according to an embodiment of the present invention; 
           [0030]      FIG. 11  is a perspective sectional view of the gas supply system prior to actuation, according to an embodiment of the present invention; 
           [0031]      FIG. 12  is a right side sectional view of the gas supply system prior to actuation, according to an embodiment of the present invention; 
           [0032]      FIG. 13  is a perspective sectional view of the gas supply system prior to actuation and showing a sequencing valve, according to an embodiment of the present invention 
           [0033]      FIG. 14  is a right side sectional view of the gas supply system prior to actuation and showing a sequencing valve, according to an embodiment of the present invention; 
           [0034]      FIG. 15  is a right side sectional view of the gas supply system after actuation, with an open main valve, according to an embodiment of the present invention; 
           [0035]      FIG. 16  is a right side sectional view of the gas supply system after actuation, with an open main valve, and showing a sequencing valve, according to an embodiment of the present invention; 
           [0036]      FIG. 17  is a right side sectional view of the gas supply system after actuation, with an open main valve, and showing a sequencing valve, according to an embodiment of the present invention; 
           [0037]      FIG. 18  is a right side sectional view of the gas supply system after actuation, with a closed main valve, and showing a sequencing valve, according to an embodiment of the present invention; 
           [0038]      FIG. 19  is a right side sectional view of the gas supply system illustrating seals, according to an embodiment of the present invention; 
           [0039]      FIG. 20  is a right side sectional view of the gas supply system illustrating a plunger retraction mechanism, according to an embodiment of the present invention; and 
           [0040]      FIG. 21  is a block diagram of a gas supply system, according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0041]    Exemplary embodiments of the present invention now will be described more fully hereinafter with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. 
         [0042]    Turning now to  FIGS. 1-21 , a gas supply system  10  is shown. The gas supply system includes a gas storage vessel (GSV)  101 , and a receiver assembly  200 . The GSV  101  is replaceable and is configured to screw into the receiver assembly via, for example, an MS port thread. A detent mechanism may be employed to prevent the GSV  101  from loosening from the receiver assembly  200 . The GSV  101  is a replaceable bottle that can be pressurized (charged) offline, for example, on another aircraft, at a land based recharging station, or at a ship based recharging station. Accordingly, a pressurized GSV  101  can be mounted to the receiver assembly  200  and used to supply pressurized gas to a store ejection mechanism. The pressurized GSV  101  can be quickly mounted to the receiver assembly  200  to allow for quick mission turnaround. 
         [0043]    The GSV  101  can be made of, for example, stainless steel, and may include a pressure gauge. The pressure gauge may include a built in overpressure venting system (not shown) that will prevent explosive bottle failure in case of fire or other causes of dangerously excessive pressure. The venting system may include, for example, a relief valve. 
         [0044]    The receiver assembly includes a housing  201 , which includes access panels/covers  204 . In some of the views, for example,  FIGS. 5 ,  6 , and  8 , the access panels/covers  204  and/or the housing  201  have been removed to illustrate some of the inner components of the receiver assembly  200 . 
         [0045]    All receiver assembly components are housed in the housing  201  and protected from environmental contamination by the access covers  204 . The receiver assembly  200  provides pneumatic and electrical connections to the aircraft. For example, the electrical connections receive operating power from, provide gas supply system status to, and receive the launch command(s) from, the aircraft weapons control system. A compressor port  218  connects to the output of a compressor  288  contained within the system  10  to optionally perform a recharging operation of the GSV  101 . The port  218  may be connected to an internal check valve in the GSV  101 . The pneumatic outlet port  216  connects to the pneumatic inlet on the bomb rack or other store supporter, so that the pressurized gas may operate the store ejection mechanisms of the bomb rack. 
         [0046]    The compressor  288  may be used to charge a depleted GSV  101  connected to the receiver assembly  200  with pressurized gas. The pressurized gas is output to a bomb rack or other store supporter, via a pneumatic outlet port  216 . Pressurized gas generated by the compressor  288  flows to the GSV  101  and is stored therein. As an alternative, the compressor  288  can provide the pressurized gas to a reservoir connected to the compressor  288  for a first level of storage, and then the pressurized gas can be provided to the GSV  101  from the reservoir. According to an embodiment, the compressor  288 , when there is a reservoir, may operate whether or not the GSV is mounted to the receiver assembly  200 . Alternatively, when there is not a reservoir, the compressor  288  will not operate unless the GSV  101  is connected to the receiver assembly  200 . 
         [0047]    The interface between the receiver assembly and the GSV  101  assemblies provides connection for individual, isolated passages between the GSV  101  and the receiver assembly  200 . A first passage connects, when actuated, the gas stored in the GSV  101  to the receiver assembly  200  and ultimately, the outlet port  216 . A second passage connects the control chamber  110  in the GSV  101  to a sequencing valve  220  (discussed below). A third passage connects the compressor port  218  to a GSV inlet check valve. 
         [0048]    When installing a GSV  101  to the receiver assembly  200 , or in a normal pre-flight check of the system, a pressure gauge on the GSV  101  is checked to insure that the GSV  101  has the specified pressure to operate the bomb rack. If not yet installed, the GSV  101  is screwed into the receiver assembly mounting thread until it is fully seated (e.g., hand tight). A protruding pin may be positioned on the back of the receiver assembly  200 , allowing a visual and/or tactile status check without powering up the aircraft. For example, if a valve actuating system of the receiver assembly is properly armed, the pin protrudes from the housing  201  of the receiver assembly. Conversely, if the valve actuating system of the receiver assembly is not properly armed, the pin will not protrude, signaling that the GSV  101  may have been depleted. The receiver assembly  200  can be re-armed manually and the GSV  101  can be replaced or re-charged. 
         [0049]    Gas is stored in the GSV  101 , and is released upon actuation of a gas release pilot poppet  102  and a main poppet  104 . Low leakage seals  103 ,  105  and  108  allow long term storage of gas in the charged vessel  101 . For example, the GSV  101  may have a 10 year storage life without significant loss of gas pressure. The pilot poppet  102  includes the seal  103  and a back-up ring (not visible in the drawings) positioned in O-ring groove  103   g , and the main poppet  104  includes seal  105  and a back-up ring  105   b  positioned in O-ring groove  105   g . The seals and back-up rings, which are made of, for example, rubber, provide a very low leakage seal and plug an orifice in the main valve poppet  104 . Since the seals  103  and  105  are pushed into the pressure source and held in the O-ring grooves by the pressurized gas leaving the GSV  101 , the seals  103  and  105  are able to perform a dual function of sealing the GSV  101 , while also acting as a poppet seats. 
         [0050]    Seal  108  is low leakage poppet style check valve seal. Like the seals  103  and  105 , the seal  108  is pushed into a pressure source (e.g., pressurized gas coming from a compressor) and held in an O-ring groove by the pressurized gas leaving the pressure source. Like the seals  103  and  105 , the seal  108  is able to perform a dual function of sealing, and also acting as a poppet seat. The check valve poppet seal  108  is formed in a conduit  237 , which leads to a passage  238  that connects to compressor port  218 . 
         [0051]    Referring, for example, to  FIGS. 11-14 , prior to actuation, a plunger  214 , which is biased by a spring  217 , is held in place by a trigger sear linkage  211 . At this point, a pilot valve poppet  102  and a main valve poppet  104  are closed so that no gas is released from the GSV  101 . 
         [0052]    A command, for example, a bomb drop command from inside the aircraft, is relayed to a solenoid  210 , which actuates the trigger sear linkage  211  to release the spring loaded plunger  214 . The plunger  214  is held in the retracted position by a trigger linkage  212  that is in turn held in position by a sear linkage and a sear pin that is moveable along its axis. The sear pin is attached to the triggering solenoid  210 , but is held in the extended position by a solenoid return spring. This trigger sear linkage  211  holds the plunger  214  retracted until the solenoid  210  is energized. 
         [0053]    Upon the launch command, the solenoid  210  is energized, the sear pin retracts, compressing the solenoid return spring, allowing the sear linkage to fold and the plunger  214  to extend, contacting the pilot poppet  102 , compressing the pilot poppet return spring  107 , and forcing the GSV main poppet  104  forward into the storage vessel  101 . 
         [0054]    A switch actuator rod  240  is connected to the top of the sear link. The switch actuator rod  240  is part of the electrical control and monitoring system and actuates an electrical switch at each end of the plunger movement. As the plunger  214  begins its extension, the now rotating sear link pushes the switch actuator rod  240 , activating a first switch, which energizes a small relay, which in turn removes electrical power from the triggering solenoid  210 . The solenoid  210 , now de-energized allows the solenoid return spring to extend the sear pin to the side of the sear linkage. Since the sear has already been released, the sear pin simply rests against the side of the sear linkage until the sear linkage and plunger retract. 
         [0055]    The spring loaded plunger  214  presses pilot valve  102  inward toward the stored gas pressure, releasing a small amount of high pressure gas into chamber A, which is a closed cavity. The increased pressure in chamber A, which is positioned behind the main valve poppet  104 , then acts on the main poppet  104  to push the main poppet  104  inward into the GSV  101  toward the pressure. As a result, the main valve opens, and pressurized gas is released to discharge port  216 . From discharge port/outlet fitting  216 , the gas travels to the store ejection mechanism to release the store. 
         [0056]    Standard O-ring seals  103  &amp;  105  can be used for low leakage valve design. Because the main valve poppet  104  is pushed into the pressure stream from the GSV  101 , the O-rings are not forced off, and instead, are held in place by the pressurized gas. In other words, by pushing the poppets  102  and  104  into the pressure source  101 , the soft rubber seals  103  and  105  are not stripped from the poppets by the pressure. Use of a soft rubber seal  103 / 105  allows very low leakage rates, which provides very long storage life, while still allowing quick release of the gas. 
         [0057]    According to an embodiment, the main valve poppet  104  has three sets of very low leakage seals with back-up rings, made from, for example, rubber. The main poppet  104  plugs, with a first set of seals  105  and back-up rings  105   b , a much larger orifice relative to the pilot valve port directly in the storage vessel  101 . A second set of seals  130  and back-up rings  130   b  with the same diameter as the first set prevents leakage of released gas to the control chamber  110  of the main poppet  104 . On the other end of the main valve poppet  104  are a piston and the third set of seals  140  and back-up rings  140   b  that is about 25% larger in diameter than the first two sets. The main and pilot poppet assembly is retained against vessel pressure by a nut. 
         [0058]    The main valve poppet  104  has a stepped diameter. A smaller diameter end SD seals the GSV  101  and a larger diameter end LD seals against chamber A. According to an embodiment, the larger end is about 25% than the end where the seals  105  are located. However, it is to be understood that the ratio of the larger diameter end LD to the smaller diameter end SD may vary depending on different applications, so long as the difference in size in large enough to overcome seal friction and spring force, and push the poppet into the gas source. 
         [0059]    More specifically, the gas released by the pilot valve  102  gathers in chamber A and is trapped against this larger diameter of the main valve poppet  104 . The larger area due to the larger diameter overcomes the force of the stored gas and the main poppet spring, which can also be used to bias the poppet  104  closed, and forces the poppet  104  inward into the GSV  101 . The difference in diameter causes the poppet  104  to move very quickly. For example, approximately 20 milliseconds (ms) or less than 20 ms elapse from actuation of plunger  214  to the high volume release of the stored gas into the outlet fitting  216 . The 20 ms period is fast enough so that any increase in the time to more than 20 ms, from plunger actuation to release of stored gas due to environmental conditions, is inconsequential to the overall performance of the system and resulting store ejection. 
         [0060]    With the pilot poppet  102  depressed by the plunger  214 , high pressure gas starts escaping from the GSV  101  and into chamber A. Gas pressure quickly rises in chamber A and begins acting upon the large diameter end LD of the main valve poppet  104 . Since there is a large difference in the area of the large diameter end (piston end) of the main valve poppet  104  versus the end SD plugging the outlet of the GSV  101 , the main poppet  104  is forced into the vessel  101 , compressing the main valve spring  109 , and opening the main valve piston ports to the stored gas. As the main poppet  104  begins to open, the main poppet seal  105  moves off the mating surface of the GSV  101 . High pressure gas from the GSV  101  travels down connecting ports in the main poppet  104 , opening an accelerator check valve, and instantaneously filling a cavity connected to discharge port  216 . At this point, the main poppet  104  quickly travels inward into the GSV  101  to its stop, and less than 20 ms or about 20 ms have elapsed. 
         [0061]    The larger diameter end LD of main valve poppet  104  is also sealed against the control chamber  110 . 
         [0062]    Referring to  FIG. 15 , after actuation, the plunger  214  retracts, and includes a mechanism that uses a small portion of the released gas to re-cock the plunger  214  and reset the trigger sear release linkage  211  for the next release. More specifically, after actuation, the plunger  214  follows the pilot poppet  102  and main poppet  104  as they retract into the GSV  101 . A small amount of high pressure gas from the rapidly pressurizing cavity connected to the discharge port is directed to a small conduit  264  down the center of the plunger  214 . Referring to  FIG. 20 , pressurized gas enters a stepped diameter piston/reversing valve interface  270 , from the back of the plunger  214 , which has an area approximately equal to the frontal area of the plunger  214 . More specifically, the gas enters into area  271  of the piston  270  through ports  265 , and then into area  272  through ports  275 . The area  272  is approximately equal to the frontal area of the plunger  214 . The differential area of the piston  270  generates a force (i.e., the force from the gas in area  272 ) that opposes the force from the gas pressure in the cavity and prevents the gas pressure from prematurely forcing the plunger  214  to the retracted position. As the plunger  214  reaches the end of its travel (the main valve poppet  104  almost fully retracted), piston face  273  on the back of the plunger  214  strikes a stationary surface  274  within the receiver assembly and opens pressure to the other side of the opposing piston  270 . When the piston face  273  strikes the surface  274 , the momentum of the plunger  214  and spring  277  opens a reversing valve. As a result, gas quickly builds pressure in a reversing volume  278 . This pressure reverses and multiplies the force on the plunger  214  and quickly retracts the plunger  214 . Since the sear pin was previously extended, the sear linkage is once again in a position to restrain the plunger  214  after the launch sequence is completed and gas pressure in the cavity returns to pre-launch atmospheric pressure. 
         [0063]    As a result, the plunger  214  can be automatically re-cocked by using the gas in the system, thereby eliminating the need to manually re-cock the plunger. Since the gas used to re-cock the plunger  214  is not available after the launching cycle is completer, automatic re-cocking occurs during the launch cycle. Accordingly, the system must compensate for the plunger retracting during the gas release cycle. In other words, there must be a mechanism in place to keep the main poppet  104  open after the plunger  214  is retracted and re-cocked. 
         [0064]    A sequencing valve  220  is used to keep the main poppet  104  in the open position after the plunger  214  is retracted and re-cocked. More specifically, a shaft  219  attached to the sear linkage connects to a bell-crank  223  set behind an access panel  204  on the side of the receiver housing  201 . As the linkage follows the plunger  214  forward, the shaft  219  and bell-crank  223  rotate, moving a sequencing valve rod  221 , and compressing a light spring  227 . 
         [0065]    For example, referring to  FIG. 14 , in the pre-actuation position, the sequencing valve rod  221  is in the extended positioned (to the left in the drawing). A sliding valve shroud  229  covers the connecting port  115  to the control chamber  110 . At this point, the pilot and main poppets  102 ,  104  are closed, and the gas in the discharge port  216  is at atmospheric pressure. 
         [0066]    Referring to  FIG. 16 , after actuation, as the sequencing valve rod  221  moves (to the right in the drawing) due to movement of the shaft  219  and rotation of the bell-crank  223 , the sliding valve shroud  229  also moves (to the right in the drawing), thereby creating a pathway from port  117  to atmosphere to connecting port  115 , so as to connect/vent the main valve control chamber  110  to outside atmosphere. 
         [0067]    Pressure (i.e., GSV gas pressure) builds in a trapped volume area  116  to further retract shroud  229  (to the right in the drawing). The pressure to the right of the shroud  229  at area  118  remains at atmosphere. At this point, a pressure differential is created on the main valve poppet  104 , whereby the pressure is at atmospheric pressure on one side of the main valve poppet due to the vent to atmosphere, and at gas pressure from the GSV  101  on the other side of the main valve poppet. The pressure differential is in place prior to the retraction of the plunger  214  so that the main valve remains open after the plunger  214  retracts. Once the plunger  214  retracts, the shroud  229  remains open due to the trapped volume in area  116  having high pressure, while pressure on the other side of the shroud  229 , at area  118 , remains at atmosphere. 
         [0068]    As gas pressure is rapidly increasing in the discharge port  216 , a port directs a small amount of gas from the discharge port  216  to an opening in the sequencing valve rod  221  aligned with the discharge port  216 , and down the rod to the small trapped volume  116  which acts on a piston attached between the sequencing valve rod  221  and the sliding valve shroud  229 . This gas retracts the shroud  229  even further, insuring that the GSV main valve control chamber  110  remains at atmospheric pressure during the remainder of the gas delivery event, even though the plunger  214  may have retracted. 
         [0069]    Referring to  FIG. 17 , the plunger  214  has retracted, and gas continues to flow out of GSV  101  through discharge port  216  until the operation of the store ejection mechanism is complete, and then the flow drops to near zero. Although the sequence valve rod  221  extends (back to the left in the drawing) as the plunger  214 , retracts, the trapped volume at area  116  keeps the sliding shroud  229  retracted enough to continue to vent the control chamber  110  to atmosphere, thereby keeping the main valve open. At this point, pressurized gas from the system leaks into chamber  119  (to the right of the shroud  229  in the drawing), at least in part due to holes  222  in the sequencing valve rod  221 . It is to be understood that in some cases, the control chamber  110  may continue to be vented until well after the launch sequence is completed. 
         [0070]    Referring to  FIG. 18 , due to the pressure increase in chamber  119 , bleeding of the trapped volume to atmosphere, and the biased force of shroud spring  230 , the shroud  229  is pushed back (to the left in the drawing), thereby blocking the vent to the atmosphere. As a result, the control chamber  110  is re-connected to the discharge port pressure, and pressure in the control chamber increases to above atmosphere to equalize pressure on both sides of the main valve poppet  104  so that the main valve spring  109  can close the main valve. The time for the main poppet  104  to return to its original position and close the main valve can be set so that full drain of gas from the GSV  101  is prevented so that the GSV  101  may be re-used for another bomb drop. Remaining gas in the GSV  101  is saved as pressure downstream of the discharge port  216  bleeds away. 
         [0071]    When the shroud  229  shifts, the control chamber  110  is closed to atmospheric pressure by blocking port  115 , and then switched to outlet port pressure. With outlet port pressure on both sides of the large piston on the GSV main poppet  104 , the poppet  104  closes from the retracted position. This prevents the GSV  101  from losing anymore of the stored gas in the vessel  101 . System pressure outside of the bottle  101  now begins to leak out of the system, eventually returning to atmospheric pressure. 
         [0072]    A block diagram of the gas supply system  10  is shown in  FIG. 21 . The gas supply system includes the compressor  288  contained therein to, when necessary, charge the gas supply system  10  with pressurized gas. The compressor  288  is connected to the GSV  101  via the compressor port  218  to supply pressurized gas to the GSV  101 . Valves, for example, check valves, can be used to control flow of pressurized gas from the compressor  288  into the GSV  101 . The GSV  101  is ultimately connected to the pneumatic outlet port  216 , through which pressurized gas is ultimately supplied to the store ejection mechanism. Gas release valves as described above are used to control the release of pressurized gas from the GSV  101  to the outlet port  216 . Accordingly, the gas supply system  10  may use pressurized gas generated by the compressor  288  and supplied to the GSV  101 , or from a GSV that has been charged offline. 
         [0073]    Although exemplary embodiments of the present invention have been described hereinabove, it should be understood that the present invention is not limited to these embodiments, but may be modified by those skilled in the art without departing from the spirit and scope of the present invention, as defined in the appended claims.