Abstract:
A gas regulating assembly controlling the pressure of gas from a gas reservoir to a pneumatically-operated device includes a primary housing surrounding a pair of gas regulators. The gas regulators are aligned in series within the primary housing between an inlet to receive high pressure gas and an outlet for releasing a controlled pressure gas. Each gas regulator includes a sealable valve that defines an input and an output, with each valve including a piston having a cylinder and a rod. A spring is adjacent said piston to force said piston cylinder away from said corresponding inlet, and a shim proximate said spring to adjust the force applied by said spring on said piston cylinder. Each valve allows gas to traverse the corresponding gas regulator until a predetermined pressure is achieved in the respective outlet of the respective gas regulator, at which point the predetermined pressure will close the corresponding valve.

Description:
CROSS REFERENCE TO RELATED PATENT APPLICATIONS  
       [0001]     This patent application claims priority from U.S. Provisional Patent Application No. 60/700,595, filed on Jul. 19, 2005, which is hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     Because small pneumatically operated devices require a supply of pressurized gas at constant pressure, many use a small tank, connected to a regulator that is attached to the device. For portability reasons, size of the respective parts becomes an important consideration. Current regulators require housings that are relatively large and difficult to machine, with air passages at an angle to the direction of flow.  
       SUMMARY OF THE INVENTION  
       [0003]     The invention described herein provides for a gas regulating assembly for controlling the pressure of gas from a gas reservoir to a pneumatically-operated device includes a primary housing for a pair of gas regulators. The gas regulators are aligned in series in the primary housing between a gas inlet to receive high pressure gas and a gas outlet for releasing a regulated gas at a predetermined pressure. Each gas regulator includes a sealable valve that defines an input and an output, with each valve including a piston having a cylinder and a rod. A spring is adjacent said piston to force said piston cylinder away from said corresponding inlet, and a shim proximate said spring to adjust the force applied by said spring on said piston cylinder. Each valve allows gas to traverse the corresponding gas regulator until a predetermined pressure is achieved in the respective outlet of the respective gas regulator, at which point the predetermined pressure will close the corresponding valve.  
         [0004]     The gas regulating assembly provides a miniature and stable assembly, with a simple housing that requires no complex machining and no undesired passages for gas flow in the housing. An embodiment of the gas regulating assembly provides a two stage design, so that as the supply pressure changes, for instance as the gas in the reservoir is consumed, the output pressure remains substantially constant for use in a pneumatically-operated device. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0005]     A two-stage gas regulator embodying the features of the present invention is depicted in the accompanying drawings, which form a portion of this disclosure, wherein:  
         [0006]      FIG. 1  is a sectional view of the two-stage gas regulator assembly fit in a housing;  
         [0007]      FIG. 2  is a sectional view of the gas regulator of  FIG. 1 , the present view illustrating the flow of gas through the two-stage gas regulator assembly;  
         [0008]      FIG. 3  is a sectional view of the two-stage gas regulator assembly;  
         [0009]      FIG. 4  is a sectional view of a first one of the two-stage gas regulator assembly;  
         [0010]      FIG. 5  is a sectional view of a second stage of the two-stage gas regulator assembly; and  
         [0011]      FIG. 6  is a block diagram of the gas regulating assembly in operation between a pneumatically-operated device and a gas reservoir.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0012]     Looking to  FIGS. 1, 2  and  6 , one embodiment of a two-stage gas or fluid regulator assembly  10  used between a gas reservoir  102  and pneumatically-operated device  100  is illustrated. The gas regulator assembly  10  includes two unbalanced regulators  12 ,  14  (stage one and stage two, respectively) that are arranged in series in a primary housing  15 , such as a cartridge or other housing, that includes a base  19  or other supporting member. The two regulators  12 ,  14  control the gas pressure from a high pressure gas HP provided from a gas reservoir  102 . The gas regulator assembly  10  has an inlet  16  where the high pressure gas HP enters the stage one, or proximal, regulator  12 , and the stage one regulator  12  will regulate the gas to provide such that a moderate or intermediate gas pressure is present at the input into the stage two, or distal, regulator  14 . The stage two regulator  14  will further regulate the gas pressure to the desired output  70  at a controlled pressure CP.  
         [0013]     Referring now to  FIGS. 3 and 4 , the stage one regulator  12  is illustrated. The stage one regulator  12  includes a regulator housing  18  that surrounds a first piston  20 . The piston  20  is slidably positioned in the regulator housing  18 , and includes a piston cylinder or block  22  with a recessed central surface connected above a piston rod or shaft  24 . A cylinder O-ring  26  is positioned between the piston cylinder  22  and the regulator housing  18 . Furthermore, the regulator housing  18  includes a base member  18   b  that is connected to first seat  27 . The first seat  27  is separated to provide one or more first stage inlets  16  that are in communication with the high pressure gas HP. A first spring  28  is positioned between the piston cylinder  22  and the base member  18   b,  and a shim  30  or series of shims is further positioned between the first spring  28  and the base member  18   b,  as discussed herein. The cavity containing the first spring  28  is vented to the atmosphere via a first atmospheric vent  29 , which may extend through the primary housing  15  and the regulator housing  18 . Thus, a constant relationship between regulated pressure and atmospheric pressure is maintained around the first spring  28 . Positioned between the base member  18   b  and the piston cylinder  22  are a back-up ring  32 , a retainer  34 , and an annulus O-ring  36 . Finally, a hollow channel  38  traverses the piston  20  connecting the stage one inlet  16  with a stage one outlet  40 .  
         [0014]     Referring now to  FIGS. 3 and 5 , the stage two regulator  12  is illustrated, which includes a regulator housing  48  that surrounds a first piston  50 . The second piston  50  is slidably positioned in the regulator housing  48 , and includes a piston cylinder  52  with a recessed central surface connected above a piston shaft  54 . A cylinder O-ring  56  is positioned between the piston cylinder  52  and the regulator housing  48 . Furthermore, the regulator housing  48  includes a base member  48   b  that is connected to second seat  57 . The second seat  57  is separated to provide one or more second stage inlets  46  that correspond with the stage one outlets  40  and are in communication with the medium gas pressure. A second spring  58  is positioned between the piston cylinder  52  and the base member  48   b,  and a shim  60  or series of shims  60  is further positioned between the second spring  58  and the base member  58   b,  as discussed herein. The cavity containing the second spring  58  is vented to the atmosphere via a first atmospheric vent  59 , which may extend through the primary housing  15  and the regulator housing  48 . Thus, a constant relationship between regulated pressure and atmospheric pressure is maintained around the second spring  58 . Positioned between the base member  48   b  and the piston cylinder  52  are a back-up ring  62 , a retainer  64 , and an annulus O-ring  66 . Finally, a hollow channel  68  traverses the piston  50  connecting the stage two inlets  56  with a stage two outlet  70 .  
         [0015]     Looking to  FIGS. 1 through 5 , the cavities containing the springs  28 ,  58  are vented to the atmosphere via atmospheric vents  29 ,  59 . The atmospheric vents  29 ,  59  may extend through the primary housing  15  and the respective regulator housings  18 ,  48 . Thus, a constant relationship between regulated pressure and atmospheric pressure is maintained in each regulator  12 ,  14 .  
         [0016]     As noted above, there are multiple seals between the pistons  20 ,  50  and their respective regulator housings  18 ,  48 . The seal on the regulated side of each piston  20 ,  30  proximate the piston cylinder  52  is the standard piston-type o-ring  26 ,  56 , which actually becomes part of the piston  20 ,  30 . In addition, the piston rod  24 ,  54  of the respective piston  20 ,  30  provides the high pressure seal, and an annulus O-ring  36 ,  66  extends around the piston rod  24 ,  54  so that the o-ring  26 ,  56  does not contribute area to the imbalance forces.  
         [0017]     Referring now to  FIG. 2 , when the gas regulating assembly  10  is initially connected to the gas reservoir  102 , or when the gas reservoir  102  is filled with the high pressure gas HP, the pistons  20 ,  50  of both stage regulators  12 ,  14  will be displaced from their corresponding seats  27 ,  57  by the force of the respective spring  28 ,  58 . The high pressure gas HP will enter the gas regulating assembly  10  through the first stage regulator  12 . That is, the spring  28  will tend to lift the piston  20  off of the first seat  24 , thereby allowing gas to flow through the first passage  38  into the second stage regulator  14 . As the gas exits the first stage  12  at the outlet  40 , it will flow into to the entrance  46  of second stage  14 . The second spring  58  will tend to lift the second piston  50  off of a second seat  57 , thereby allowing gas to flow through a second passage  68  traversing the second piston  30  into the second stage regulator  14  and exiting at outlet  70  for use by a pneumatically-operated device  100 .  
         [0018]     As pressure in the outlet  70  of the second stage  14  increases to be used by the pneumatically-operated device  100 , a force F 2  proportional to the pressure in said outlet  70  will develop on the second piston  50 . This force F 2  will counteract the force of the second spring  58 , and when the force F 2  is great enough, the second piston  30  will be forced against the second seat  57 , thus preventing gas flow through the second passage  68  traversing the second piston  50 . As a result, the gas supplied from the second stage  14  is maintained at a controlled pressure CP as desired the user.  
         [0019]     Similar to the operate of the stage two regulator  14 , as pressure in the outlet  40  of stage one regulator  12  increases, a force F 1  proportional to the intermediate pressure in said outlet  40  will develop on the piston  20 . This force F 1  counteracts the force of the spring  28 , and when the force F 1  is great enough, the piston  20 , and in particular, the piston rod  24  will be forced against the first seat  27 . Once the piston rod  24  abuts the first seat  27 , the first passage  38  traversing the piston  20  will be blocked preventing further gas flow through the first passage  38 . Thus, the variable high pressure gas HP from the gas reservoir  102  will be managed at a consistent pressure CP that is usable by the corresponding pneumatically-operated device  100 .  
         [0020]     As provided above, the high pressure gas HP from the gas reservoir  102  will initially engage the inlet  16  at a high pressure. However, once the high pressure gas HP has been released to the gas regulating assembly  10 , the pressure of the high pressure gas HP will decrease. Furthermore, the pressure will continue to decrease as the pneumatically-operated device  100  is operated, such that the pressure of the high pressure gas HP will eventually be equivalent to the atmospheric pressure and consequently not provide the necessary requirements for operation of the pneumatically-operated device  100  until the reservoir  102  is replenished or a new reservoir  102  is connected to the gas regulating assembly  10 . Nevertheless, as the pressure of the high pressure gas HP varies, the gas regulating assembly  10  will continue to provide the controlled gas CP having a pressure needed for proper operation of the pneumatically-operated device  100 .  
         [0021]     Axial flow of gas occurs through the channels  38 ,  68  traversing the piston  20 ,  50 . The high pressure HP initially engages the gas regulator assembly  10  at the outside surface of the piston rod  24 . The seat  27 ,  57  of each regulator  12 ,  14  may include a rubber surface. With respect to the stage one regulator  12 , the distal edge of the piston rod  24  will substantially seal the channel  38  when the piston rod  24  abuts against the seat  27 .  
         [0022]     Most of the imbalance in a gas regulator assembly  10  is a function of the ratio of the area of the piston  20 ,  30  exposed to the regulated pressure that tends to close the respective gas regulator  12 ,  14 , and the area exposed to the high pressure that tends to open the respective gas regulator  12 ,  14 . The greater this ratio, the less imbalance the regulator displays. Conventional gas regulators use large pistons or diaphragms to solve this problem, but that is prohibitive when the design is to fit into a small space or a small housing, such as a cartridge. Since one objective of this gas regulator assembly  10  is to minimize the size occupied by the assembly  10 , a large piston was not feasible. Consequently, each stage regulator  12 ,  14  minimizes the area exposed to high pressure. When the piston rod  24 ,  54  engages the seat  27 ,  57 , high pressure is substantially maintained on the side of the piston rod  24 ,  54  and regulated pressure on the inside. The seal takes place across the cross section of the wall of the piston rod  24 ,  54  at the end of the piston  20 ,  50 . The area of the piston  20 ,  30  exposed to the high pressure gas HP, which tends to displace the piston  20 ,  30  from the respective seat  27 ,  57 , is the area from the retainer  34 ,  64  and annulus O-ring  36 ,  66  from the outside of the piston rod  20 ,  30  to a lead-in  17 ,  47  where the final seal of the piston rod  20 ,  30  occurs on the seat  27 ,  57 . By making the wall of the piston rod  20 ,  30  thin, this area exposed to the high pressure gas HP is minimized.  
         [0023]     Stage one  12  and stage two  14  are functionally identical and are interchangeable. The springs  28 ,  58  of each stage  12 ,  14  are designed with a high spring constant (k) so that very small changes in preload can cause significant changes in spring force. That is, the addition of thin shims  30 ,  60  between the springs  28 ,  58  and base member  28   b,    48   b  can substantially adjust the spring force applied to the respective piston  20 ,  50 . The output pressure is set by the addition of a shim  33 ,  43  or shims under the respective spring  22 ,  32  to increase the preload, and thereby the output pressure  28 ,  38 . The spring constants k of the first and second regulating stages  12 ,  14  are set individually to the desired output pressure, although the spring constants k of each spring  28 ,  58  may be equivalent. Therefore, the springs  28 ,  58  and shims  30 ,  60  will determine the output pressure, with the input pressure slightly above the desired output pressure.  
         [0024]     As an example, if 150 PSI is the desired output pressure, the regulator stages  12 ,  14  would be set to 150 PSI at 200 PSI input pressure. With this arrangement, as the reservoir  102  pressure drops from 3,000 PSI to 200 PSI, the output from the first stage  12  would vary from about 240 PSI to 150 PSI, and the output from the second stage  14  would vary from around 155 PSI to 150 PSI. Thus, by arranging the first stage regulator  12  and the second stage regulator  14  in series, the user is able to regulate the high pressure HP flowing into the assembly  10  into which a controlled pressure CP flows from the assembly  10 .  
         [0025]     More specifically, the high pressure gas is regulated by the stage one regulator  12  to a pressure that is at all times greater than the desired final outlet controlled pressure CP. Due to the imbalance, the outlet  40  of the stage one regulator  12  will vary depending on the pressure at the inlet  16  of the stage one regulator  12 . For instance, as the inlet pressure HP varies from 3,000 to 300 PSI, the outlet pressure from stage one  12  may vary from 300 to 200 PSI. This intermediate regulated pressure at the outlet  40  is then directed into a substantially identical, stage two regulator  14 , which further adjusts the gas pressure to the desired controlled pressure CP at the second outlet  70 . As the outlet pressure from stage one  12  varies from 300 to 200 PSI, the outlet pressure from stage two  14  may vary from 155 to 153 PSI. Thus, by using two unbalanced regulators  12 ,  14  in series, the output control pressure CP from the gas regulating assembly  10  remains effectively constant as the input pressure HP varies.  
         [0026]     An important aspect of this design includes its small size. The entire gas regulating assembly  10  can be positioned in a small cavity, such as a circular cavity that is only 0.545 inches in diameter and just over one inch long. Another important aspect is the fact that all flow and sealing is axial, thus no external sealing is required. Since no external sealing is required, manufacturing the cavity becomes much simpler and therefore cheaper. In particular, no O-ring grooves need to be machined into the cavity, and the overall tolerances and finish requirements can be much looser. The only requirement is that there be a seal at the ends of the cavity  
         [0027]     While this invention has been described with reference to preferred embodiments thereof, it is to be understood that variations and modifications can be affected within the spirit and scope of the invention as described herein and as described in the appended claims.