Abstract:
The present invention is a poppet comprising a stem and a body, with the body having a plurality of channels extending in an longitudinal direction along the periphery of the body. The channels are gas flow conduits that react to the orientation of the poppet and force the poppet to re-align itself during operation with the centerline of the regulator chamber surrounding the poppet. The plurality of channels greatly reduces the contact between the periphery of the poppet and the regulator body. The present invention further includes a bore beginning at the non-stem end of the body and extending in the longitudinal direction within the body of the poppet. The bore can receive a spring for guiding the poppet. By positioning the spring within the poppet, the spring will have minimal contact with the regulator body. The bore avoids the spring from guiding the poppet by its end and adjusts the poppet&#39;s center of gravity toward where the poppet sits on the seat. The bore is also a part of a dead zone volume that traps debris.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a self-balancing poppet in a compressed gas flow. The poppet may be used in a regulator in fuel storage and delivery systems. 
     Compressed gas can be stored in tanks at high pressures such as 10,000 psi. With such high pressures, the pressure of the gas must be reduced before use. To achieve the necessary pressure reduction, a regulator is typically used. The regulator has a seat and a poppet, and the dynamic motion between the seat and poppet provides the necessary pressure reduction. The poppet moves away from the seat to allow the intended outlet pressure to be reached. Once the outlet pressure is reached, the poppet sits on the seat. The contact surface between the poppet and the seat as the poppet sits on the seat seals the compressed gas from the outlet. 
     The seal produced by the poppet sitting on the seat is formed during the first release of the compressed gas. The poppet is pressed into the seat, which can be made of metal and non-metallic material, to form the seal surface. For every subsequent release of compressed gas, the poppet must return to the seat at the initially formed position. If the poppet returns to the seat at a different angle or lateral position, then the poppet and the seat do not completely seal the compressed gas from the outlet. The result is a leak. 
     Aside from its contact with the seat, the poppet is in contact with the body of the regulator. Both the poppet and the body of the regulator can be made of metal. As the poppet repeatedly moves to and from the seat, its metallic periphery rubs against the metallic surface of the regulator&#39;s body. Such rubbing creates friction which affects the movement of the poppet. It also wears away the periphery of the poppet. This not only affects the alignment of the poppet with respect to the seat but also shortens the life of the regulator. Moreover, debris is produced from the metal-to-metal contact. Given the high rate of flow, such debris can impact the seat with momentum and carve a leak path, thereby negatively affecting the seal between the poppet and the seat. 
     A poppet may be attached to a spring which guides the poppet by urging it toward the seat. If the spring is positioned around the periphery of the poppet, the spring will contact the metal surface of the regulator body as the poppet moves to and from the seat. As with the contact between the poppet and regulator body, the contact between the spring and regulator body generates debris. The spring&#39;s contact with the poppet can also generate debris. If such debris is not contained, it can impact the seat with momentum and carve a leak path, thereby negatively affecting the seal between the poppet and the seat. 
     Typically, the spring is placed at the end of the poppet. Having the poppet guided at its end is not advantageous. A small degree of tilt at the end produces a much larger lateral displacement where the poppet sits on the seat. A similar result occurs when the poppet&#39;s center of gravity is near its end. If the center of gravity of the poppet is near its end, it will rotate about its end, thereby producing a much larger lateral displacement where the poppet sits on the seat. 
     BRIEF SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a poppet that is self-balancing and will return to the seat at the initially formed position for the life of the regulator. 
     It is another object of the present invention to provide a poppet that has minimal contact with the regulator body. 
     It is another object of the present invention to provide a poppet that is guided by a spring which has minimal contact with the regulator body. 
     It is yet another object of the present invention to provide a poppet that is not guided at its end. 
     It is yet another object of the present invention to provide a poppet with a center of gravity near where it sits on the seat. 
     It is yet another object of the present invention to contain dynamic debris generated by the repetitive motion between the spring and the poppet and the spring and the regulator body. 
     To accomplish the above objects, one embodiment of the present invention is a poppet comprising a stem and a body, with the body having a plurality of channels extending in an axial or longitudinal direction along the periphery of the body. The channels are gas flow conduits that react to the orientation of the poppet. If the poppet is biased in one direction, the gas flowing in the channel corresponding to the biased direction becomes compressed. The resulting increase in pressure from the compression creates a force that re-orients the poppet until its aligned with the centerline of the regulator chamber surrounding the poppet. In this manner, the poppet is self-balancing. This self-balancing feature prevents the poppet from returning to the seat at a different angle or lateral position from the initially formed position. 
     The plurality of channels greatly reduces the contact between the periphery of the poppet and the regulator body. The remaining contact surface comprises the ribs between the channels. Contact between the periphery of the ribs and the regulator body, however, is limited due to the self-balancing feature of the poppet. When the poppet is balanced, a layer of compressed gas exists between the periphery of the rib and the regulator body. This layer of compressed gas acts as an gas bearing that reduces friction and debris associated with metal-to-metal contact and extends the life of the regulator. 
     The embodiment of the present invention further includes a bore beginning at the non-stem end of the body and extending in the longitudinal or axial direction within the body of the poppet. The bore can receive a spring for guiding the poppet. By positioning the spring within the poppet, the spring will have minimal contact with the regulator body, thereby reducing debris associated with the spring contacting the regulator body. 
     The bore can extend through a substantial portion of the poppet&#39;s body. A lengthy bore avoids the spring from guiding the poppet by its end. Instead, the spring couples to the poppet near where the poppet sits on the seat and thus guides the poppet through a large portion of the poppet&#39;s body. This arrangement prevents a small degree of tilt from generating a much larger displacement where the poppet sits on the seat. Moreover, a lengthy bore adjusts the poppet&#39;s center of gravity toward where the poppet sits on the seat. 
     In one embodiment, the body of the poppet is divided into three sections: a first body section near the stem, a second body section at the non-stem end and a third body section in between the first and second body sections. The first and second body sections are used to align the poppet in the regulator body. The third body section can have a cylindrical shape with a smaller diameter than the first and second body sections and can be aligned with the inlet passageways that deliver gas to the chamber. This allows high pressure gas to have a uniform flow from the inlet passageways and to move freely around the poppet in a circumferential direction. 
     The first body section may be designed to have channels allowing high pressure gas to flow through the seat as the poppet moves away from the seat. When the poppet moves away from the seat, the difference in pressure between the compressed gas and the outlet forces the gas through the seat and into an outlet chamber. The placement of channels in the first body section facilitates the flow of gas into the outlet chamber, thereby allowing it to be filled quickly. This feature is particularly important when the gas is immediately needed, such as in internal combustion and alternative fuel engines. 
     The second body section may abut a spring hole in the regulator body to which the spring is attached. The second body section and the spring hole in contact create a dead flow zone. The dead flow zone comprises the volume of the bore and the spring hole. In this zone, the high pressure gas is stagnant. As the poppet moves, the spring is repetitively compressed and expanded. The contact of the spring with the poppet and the regulator body during such motion may generate metal debris from the spring. The metal debris, if allowed to enter the fluid flow, can damage the seat by carving the seat and creating a leak path. The dead flow zone allows the debris to be confined in the bore and the spring hole, thereby protecting the seat from damage, increasing the life of the regulator and avoiding leakage. 
     These and other features and advantages of the present invention will be apparent to those skilled in the art from the following detailed description of the embodiments of the invention, when read with the drawings and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a perspective view of one embodiment of the present invention. 
         FIG. 2  is a front view of the embodiment of  FIG. 1  surrounded by the body of a regulator. 
         FIG. 3  is a cross-sectional view of  FIG. 2  taken along section  3 — 3 . 
         FIG. 4  is a perspective view of motor vehicle having a storage vessel and utilizing an apparatus for regulating a fluid. 
         FIG. 5  is a perspective view of the storage vessel of  FIG. 4  with an partial internal view illustrating the apparatus of  FIG. 4 . 
         FIG. 6  is a partial cross-sectional view of the apparatus of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following description of preferred embodiments, reference is made to accompanying drawings which form a part hereof and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the preferred embodiments of the present invention. 
       FIGS. 1–3  illustrate one embodiment of the present invention in different views. The following description will reference all three figures. It should be noted that all figures display the appropriate directional markers. For the purposes of the following description, the x-direction may also be referred to as the axial direction or the longitudinal direction while the y-direction may also be referred to as the vertical direction. It should also be noted that  FIG. 1  does not illustrate the regulator body  200  as illustrated in  FIGS. 2 and 3  nor the spring  300  as illustrated in  FIG. 3 . 
     The poppet  100  comprises a stem  101  and a body  102  tapering at one end to the stem  101 . This end of the body is sometimes referred to herein as the stem-end of the body, and the body&#39;s other end is sometimes referred to as the non-stem end. The body  102  can be further divided into a first body section  102   a  (near the stem-end but not including the tapered section  108 ), a second body section  102   b  and a third body section  102   c  between the first body section  102   a  and the second body section  102   b . The first body section  102   a  has a plurality of channels  103  interleaved with ribs  105 . Each channel  103  extends in the longitudinal direction along the periphery of the first body section  102   a . It should be noted that the term channel refers to a groove or indentation on the periphery of the poppet and is not to be limited in any way in terms of shape, size or texture. 
     The second body section  102   b  also has a plurality of channels  104 , each extending in the longitudinal direction along the periphery of the second body section  102   b . As with the first body section  102   a , the second body section  102   b  includes ribs  106  interleaved with the channels  104 . The poppet  100  further comprises a bore  107  extending in the longitudinal direction from its non-stem end. 
     As illustrated in  FIGS. 2 and 3 , the poppet  100  is positioned within a chamber  201  of the regulator body  200 . During operation, the poppet  100  moves back and forth in the chamber  201  along the longitudinal direction. A fluid, such as compressed hydrogen gas, flows along the channels  103  and  104 , separating the poppet  100  from the surface of the chamber  201 . The distance between the chamber surface and the surface of the lower-side channel  103   a  is d 1  while the distance between the chamber surface and the surface of the upper-side channel  103   b  is d 2 . 
     As discussed above, it is preferable for the poppet  100  to maintain its alignment with the centerline of chamber  201 . The distance d 1  would be equal to the distance d 2  at this position. However, during operation, the poppet  100  may be biased in one direction. For example, if the stem-end of the body  102  descends in a vertical direction, the distance d 1  will be less than the distance d 2 . The reduction in the distance d 1  and the corresponding reduction in volume compresses the gas flowing along channel  103   a . As is known to one of ordinary skill in the art, the pressure of the compressed gas will increase and will exert a force on the poppet  100 . The force will push the poppet  100  in a vertical direction, until the pressure on the upper-side channel  103   b  is equal to the pressure on lower-side channel  103   a  and the distance d 1  is equal to the distance d 2 . In this manner, the poppet  100  is self-balancing. This feature prevents the poppet from having a biased position, particularly as it returns to the seat, and ensures that the poppet will return to the seat at the initially formed position. 
     The self-balancing feature works regardless of whether the poppet is biased downwardly or upwardly in the y-direction or whether the poppet is biased in the y-direction or the z-direction. 
     As illustrated in  FIGS. 1 and 2 , the channels  103  and  104  significantly reduce the contact surface of the poppet  100 . The contact surface comprises the ribs  105  between the channels  103  in the first body section  102   a  and the ribs  106  between the channels  104  in the second body section  102   b . Contact between the ribs  105 ,  106  is further limited by the self-balancing feature of the poppet  100 . When the poppet is balanced, a layer of compressed gas exists between the periphery of each rib and the surface of chamber  201  which is displayed as the distance d 3  in  FIG. 3 . This layer of compressed gas acts as a bearing that reduces friction, reduces any debris associated with metal-to-metal contact and extends the life of the poppet and the regulator. It should be noted that the poppet of the present invention does not have to be made of metal. To further reduce contact debris, the poppet may be made of non-metallic materials such as plastics and ceramics. The poppet can also be a hybrid having metal embedded in plastic. 
     The contact surface of the poppet  100  is further reduced through the structure of the third body section  102   c . The third body section  102   c  has a cylindrical shape (although other shapes can be employed). As illustrated in  FIGS. 1 and 2 , the radius of the third body section  102   c  is equal to the radial length r 1 , which is the distance from the centerline of the poppet  100  to the lowest point of channel  103 ,  104 . In contrast, the distance r 2  from the centerline of the poppet  100  to the periphery of the rib  105 ,  106  is longer. Accordingly, the periphery of the third body section  102   c  never contacts the surface of chamber  201 . 
     This feature can be further maximized by extending the length L 3  of the third body section  102   c  with respect to the length L 1  of the first body section  102   a  and the length L 2  of the second body section  102   b .  FIG. 3  illustrates that the length L 3  is longer than the length L 1  of the first body section  102   a  and the length L 2  of the second body section  102   b . Furthermore, length L 3  can be longer than the combined length of L 1  and L 2 . Of course, other combinations can be used, such as having the length L 3  equal to the combined length of L 1  and L 2 . 
     In this manner, the length of contact is not the entire length L of the body  102 , but rather is limited to the sum of L 1  and L 2 . Limiting the contact length is particularly advantageous when the regulator is not in use, such as when the regulator is being shipped. No compressed gas flows through the chamber  201  of the regulator  200  when it is not in use. The poppet  100  accordingly rests on the surface of chamber  201  without a gas bearing. However, the poppet  100  may still move in transit. Minimizing the contact length between the poppet  100  and the chamber  201  limits friction associated with such movement and extends the life of the regulator. 
     Contact with the surface of the chamber  201  is further limited by the placement of the spring  300 . The spring  300  is attached loosely or firmly at one end to the spring hole  202  of the regulator  200 . The bore  107  receives the other end of the spring  300  near the stem-end of the body as conventionally illustrated at reference numeral  301 . As a result, the spring  300  is not positioned on the periphery of the body  102  of the poppet  100 , but rather is positioned within the body  102 . This structure minimizes the contact between the spring  300  and the surface of chamber  201 , thereby reducing the debris associated with such contact. 
     It should be noted that the positioning of the spring  300  has an additional benefit. In certain regulators, the spring hole  202  may not be properly aligned with the chamber  201  due to machining error. If poppet is designed to have a body section inserted in the hole, the poppet will be misaligned as well. In contrast, spring  300  (rather than the poppet body) is coupled to the spring hole  201  and, thus, compensates for any misalignment between the spring hole  202  and the chamber  201  without affecting the alignment of the poppet  100 . 
     The bore  107  that receives the spring  300  extends in the longitudinal direction from the non-stem end of the poppet  100 . As illustrated in  FIG. 3 , the length of the bore  107  extends through the second body section  102   b  and the third body section  102   c . As discussed above, a small degree of tilt at the non-stem end produces a large displacement where the poppet sits on the seat. The length of the bore  107  avoids such a large displacement. The bore&#39;s length allows the spring  300  to be connected to the poppet  100  at reference numeral  301 , thereby coupling the spring to the poppet where it sits near the seat and utilizing a substantial portion of the body  102  of the poppet  100  for guidance. In this manner, a small degree of tilt at  301  produces a much smaller displacement where the poppet sits on the seat as compared to the same small degree of tilt at the non-stem end of the poppet  100 . 
     The bore&#39;s length also affects the center of gravity of poppet  100 . A poppet rotates about its center of gravity during operation. It is preferable to have the center of gravity near where the poppet sits on the seat as opposed to near the non-stem end for the same reasons as discussed immediately above. Because the bore  107  is hollow, a lengthy bore shifts the center of gravity toward where the poppet  100  sits on the seat. As illustrated in  FIG. 3 , the poppet&#39;s center of gravity  109  is near where the poppet  100  sits on the seat (not illustrated). 
     The present invention is not limited to the embodiment illustrated in  FIGS. 1–3 . Many structural variations can be made without departing from the scope of the invention. 
     Although  FIGS. 1 and 3  illustrate a body  102  separated into three sections, the body  102  of the present invention may be separated into any number of sections or no sections at all. If the present invention employs body sections, it is not limited to the arrangement illustrated in  FIGS. 1 and 3  with a small third body section  102   c  sandwiched between larger body sections  102   a ,  102   b.    
       FIGS. 1 and 3  illustrate the body sections  102   a ,  102   b ,  102   c , but do not reference the tapered section  108  of the body  102  as a body section. The tapered section  108  can have any of the features of the body sections disclosed herein, such as channels. Furthermore,  FIG. 3  illustrates the body  102  and the stem  101  as being integral. The present invention may have a stem  101  and a body  102  that are separate members joined together in any manner. 
     Although  FIG. 1  illustrates four channels  103  on the first body section  102   a  and four channels  104  on the second body section  102   b , any number of channels may be used.  FIG. 1  also shows that the four channels  104  on the second body section  102   b  are aligned with the channels  103 . The number of channels in each body section do not have to be equal nor do channels between body sections have to be aligned. 
     Although  FIG. 1  illustrates the channels  103  extending linearly along the periphery of the first body section  102   a , the channels  103  may extend in any manner along the periphery of the body. For example, the channels  103  may extend in a spiral manner.  FIG. 1  also illustrates each channel extending linearly, whereas the present invention may have one or more channels extending in one manner with one or more channels extending in another manner.  FIG. 1  also illustrates the channels  104  of the second body section  102   b  extending linearly along the second body section  102   b . The present invention is not limited to having each body section have their respective channels extend in the same manner. 
       FIG. 1  also shows that each of the channels  103  has a predetermined length. In the case of a body  102  without any sections, the channels can extend from one end of the body to another end or any other length. It should be noted that the present invention may have the body or a body section where the channels in the body or body section have different lengths. For example, one or more channels can extend for the full length of the body or body section, with one or more other channels extending for a half length of the body or body section. It should also be noted that  FIG. 1  further shows the length of the channels  103  is different than the length of the channels  104 . The present invention may have body sections in which the channels are the same length in all or some of the body sections. 
     Although  FIG. 2  illustrates channels  103  as having an arcuate cross-sectional shape, the present invention is not limited to channels having arcuate shapes. Other shapes, such as rectangular and semi-circular, can be chosen.  FIG. 2  further illustrates that the same arcuate cross-sectional shape is utilized for each channel. The present invention may employ channels in the body or a given body section or sections with different cross-sectional shapes.  FIG. 2  also illustrates each channel having the same radial length r 1  and each rib having the same radial length r 2 . The present invention may have channels with different radial lengths r 1  and ribs having different radial lengths r 2 . 
       FIG. 1  illustrates the same arcuate cross-sectional shape in the first body section  102   a  and the second body section  102   b . The present invention may employ different cross-sectional shapes in different sections, and different radials lengths r 1  and r 2  in different sections. 
       FIG. 3  illustrates the bore  107  extending through the second body section  102   b  and the third body section  102   c . The bore may have a different length. Furthermore, the bore  107  is not limited to having a cylindrical shape. It can, for example, be tapered or have a frustum shape.  FIG. 3  also illustrates the third body section  102   c  having a radius that is equal to the radial length r 1 . The radius of the third body section  102   c  may be greater than or smaller than radial length r 1 . If the radius of the third body section  102   c  is greater than radial length r 1 , it may be equal to radial length r 2  and, thus, flush with the periphery of the first body section  102   a  and the second body section  102   b . If the third body section  102   c  is not cylindrical, it may have a radial length from the poppet&#39;s centerline that is less than, equal to or greater than the radial length r 1 . 
       FIG. 4  illustrates a motor vehicle  1000  utilizing an apparatus for regulating a fluid. The motor vehicle  1000  may be an alternative fuel vehicle, with the storage vessel  1001  storing hydrogen, compressed natural gas or any other alternative fuel. The storage vessel  1001  is connected to a module  1002 . The module  1002  is, in turn, connected to a fuel line  1003 . The fuel line delivers the alternative fuel to engine  1004 . The engine  1004  can be an alternative fuel engine such as a hydrogen fuel cell. 
       FIG. 5  provides a partial internal view of the storage vessel  1001 . Mounted onto to the module  1002  is the apparatus  200  for regulating the alternative fuel. 
       FIG. 6  illustrates a partial cross-sectional view of the apparatus  200  for regulating the alternative fuel. The apparatus is, without limitation, a regulator. Reference numerals in  FIG. 4  that are the same as reference numerals in  FIGS. 1–3  refer to the same structural component. 
     The apparatus comprises a body  200  having a first chamber  201  and a second chamber  203 . In the first chamber  201 , a poppet  100  and a spring  300  are positioned. One end of the spring  300  is coupled to the body  200  within spring hole  202 . The other end of the spring  300  is coupled to poppet  100 . Bore  107  of the poppet  100  receives the spring  300 . Poppet  100  has a stem  101  and a body  102  tapering to the stem  101  as indicated by reference numeral  108 . The body is divided into three body sections, with a first body section  102   a , a second body section  102   b  and a third body section  102   c  between the first body section  102   a  and the second body section  102   b . The first body section  102   a  has a plurality of channels (not shown) extending in a longitudinal direction along the periphery of the first body section  102   a . The channels are interleaved with ribs  105 . The second body section  102   b  has a plurality of channels (not shown) extending in the longitudinal direction along the periphery of the second body section  102   b . These channels are interleaved with ribs  106 . The third body section  102   c  has a radial length that is less than the radial length to the ribs  105 ,  106  from the centerline of the poppet  100 . 
     Poppet  100  is movable in the longitudinal direction in the first chamber  201  for regulating the flow of a fluid between the first chamber  201  and the second chamber  203 . As discussed above, the fluid may be a gas, such as hydrogen fuel, natural gas and other compressed gases. The gas flows from a storage tank  1001  to the apparatus  200  in a manner known to one of ordinary skill in the art. The gas is delivered to the first chamber  201  through inlet passageways  204  and  205 . The third body section  102   c  is aligned with the inlet passageways  204  and  205 . This allows the entering gas to have a uniform flow and to move freely in a circumferential direction around poppet  100 , including the third body section  102   c . The gas and the spring  300  urge the poppet  100  in a longitudinal direction toward the second chamber  203 . In the second chamber  203 , a piston  500  is slidably arranged and urged by piston spring  600 . As the gas and the spring  300  urge the poppet  100  toward the second chamber, the stem  101  of the poppet  100  extends through a seat  400  and abuts the piston  500  in the second chamber  203 . When the desired pressure is reached in the second chamber  203 , the tapered section  108  of the poppet  100  rests on seat  400 , thereby sealing the compressed gas in the first chamber  201  from the second chamber  203 .  FIG. 6  illustrates the poppet  100  at this position. 
     The gas in the second chamber  203  may be used, for example, to fuel the alternative fuel engine  1004  (or any equipment requiring the regulation and control of high pressure gases). As the gas is used, the pressure of the second chamber  203  is reduced. The reduction in pressure allows the piston spring  600  to urge the piston to push the stem  101 . The poppet  100  moves away from the seat, thereby allowing compressed gas to refill the second chamber  203  at the desired pressure. 
     In this manner, the poppet  100  is movable in the longitudinal direction to and from the seat  400  for regulating fluid. If the poppet  100  becomes biased as it is moves, the plurality of channels on the first body section  102   a  and the second body section  102   b  allow it to re-align itself as discussed above and to return to the seat  400  at the initially formed position. The plurality of channels and the radial length of the third body section  102   c  reduce the amount of contact between the poppet  100  and the surface of the first chamber  201 . The gas bearing further reduces any chance of contact. Moreover, the placement of the spring  300  in the bore  107  eliminates the contact between the spring  300  and the surface of the chamber  201  and avoids the poppet  100  from being guided by the spring  300  at its non-stem end. The length of the bore allows the center of gravity of the poppet  100  to be near where the poppet  100  sits on the seat  400  as well. 
     As the poppet  100  moves back and forth in the longitudinal direction, the spring  300  may contact the regulator body or the poppet  100 . Such contact may shred metal chips off the spring  200 , the poppet  100  or even the regulator body. If the debris enters the flow of gas as the gas enters the first chamber  201  from inlet passageways  204  and  205 , it can damage the seat  400  and other parts. To confine such debris, the apparatus  200  maintains a volume  700  between the non-stem end of the poppet  100  and the surface of the spring hole  202 . The volume comprises the volume of the bore  107 , spring hole  202  and a portion of the first chamber  201 . In the position illustrated in  FIG. 6 , the pressure in the volume  700  and the remainder of the overall chamber  201  is the same. Thus, no gas is exchanged between the volume  700  and the remainder of the overall chamber  201 , and any debris associated with the spring  300  remains in volume  700 . When the poppet  100  moves away the seat, the pressure in the volume  700  increases slightly and compressed gas enters chamber  201  through inlet passageways  204  and  205 . Any debris associated with spring  300  is trapped in the volume  700  and is not introduced into the gas that enters the second chamber  203 . Thus, although the volume  700  changes as the poppet  100  moves in the longitudinal direction, the high pressure gas in this volume is stagnant. The stagnant high pressure prevents any gas from entering volume  700  and prevents any debris from entering into the gas flow. 
     Although the present invention has been described with the use of hydrogen compressed gas, any type of fluid whether compressed or otherwise may be used. The fluid furthermore is not limited to a gas. Although the present invention has been described in connection with an alternative fuel vehicle, it can be used with any type of motor vehicle including, but not limited to, motor vehicles having internal combustion engines operating on gasoline and motor vehicles having hybrid combustion/electrical engines. It should be noted that present invention may also be used in stationary devices, such as refueling stations, or any other gas management systems. 
     Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the present invention as defined by the appended claims.