HK1077647B - Pneumatic pressure regulator assembly - Google Patents

Description

Pneumatic pressure regulator device

Technical Field

The present invention relates generally to pressure regulators and, more particularly, to pneumatic pressure regulators having an adjustable regulator piston.

Background

Pneumatic pressure regulators are well known in the art and are used in many instances to facilitate regulating a pneumatic supply pressure to a specified system pressure. The controlled system pressure provided by the pressure regulator is then used to operate various pneumatics within the system. The pressure regulator is used to maintain a desired operating pressure and to eliminate supply pressure fluctuations. In this way, the voltage regulator ensures that the active system devices will operate properly under reliable and repeatable actuation.

In applications, there are a variety of manufacturing and processing environments that desire higher compressed gas flow rates and extremely fast response times. It is important to supply precisely regulated air pressure to active devices in these environments. As processing technology in these production environments has improved, the need for smaller and more accurate active air devices has increased, as well as the need for smaller and more accurate pressure regulators for controlling supply pressure. In addition, depending on the particular application, multiple regulators may be used at various locations throughout the pneumatic system, even to the extent that a single regulator is provided for each individual active device, for greater control and accuracy. In these cases, it is preferable to place the voltage regulator in close proximity to the active device. This in turn places the regulators in close proximity to the manufacturing and processing environment, thus requiring the regulators to be placed in tight spaces with extremely small dimensions.

Known pressure regulators that utilize a diaphragm to control output pressure are generally too large to be used in these situations. This is a factor that has driven the current improvements and improvements in piston-controlled pressure regulators. Pressure regulators of this type typically use a piston movably supported in a bore. The piston is used to regulate the downstream pressure acting on it. The piston is operatively connected to or associated with the lift control valve to act as a piston that moves with the downstream pressure. More specifically, when the downstream pressure exceeds the desired maximum, control is continued so as to adjust the input pressure to the desired output pressure.

Piston type regulators are generally more suitable for use in the tight confines of the operating environment described above than diaphragm operated regulators of the type generally known in the art. However, in the past, certain designs of barrier layers have limited the extent to which the piston size, and thus the regulator itself, can be reduced. When the effective surface area of the piston decreases below a predetermined amount, precise pressure control may be lost. To overcome this problem, larger piston controlled pressure regulators known in the related art may be used remote from the rest of the pneumatic system. However, these larger, remotely located regulators may encounter continuity requirements that they must be interconnected by piping or other flow passages, which require additional hardware and plumbing, and may reduce pneumatic efficiency and cause line losses within the system.

While larger, remotely located regulators have generally been suitable in the past, there is a continuing need in the art for a simple pneumatic system that reduces manufacturing and/or assembly costs by creating smaller yet still highly accurate piston controlled regulators. Smaller pressure regulators may be placed in close proximity to active system components, thereby shortening the flow path, reducing or eliminating auxiliary plumbing and hardware, and increasing pneumatic flow efficiency. The smaller regulators that have been proposed in the related art fail to address the problems that arise when the effective surface area of the piston falls below the minimum piston size in an attempt to achieve the desired regulator size criteria.

Disclosure of Invention

The present invention overcomes the disadvantages of the related art pneumatic pressure regulator devices.

According to the present invention there is provided a pneumatic pressure regulator assembly comprising: a voltage regulator housing, the voltage regulator housing having: an inlet adapted to be in fluid communication with a source of pneumatic pressure at a first elevated pressure; at least one outlet adapted to provide pneumatic pressure to at least one downstream pneumatic device at a second, lower regulated pressure; a regulator valve assembly having a valve member movably supported in a regulator housing between an open position and a closed position; and a piston assembly movably supported in the regulator housing and operative to bias the valve member to its open position when the downstream pressure flowing through the outlet is below a predetermined value, the piston assembly including a pressure responsive surface forming a geometry having a major axis a and a minor axis B, wherein the major axis is greater than the minor axis, the piston assembly being responsive to gas pressure flowing between the inlet and the outlet to reduce the biasing force on the valve member so that the valve member moves to its closed position when the downstream pressure flowing through the outlet exceeds the predetermined value.

An advantage of the present invention is that it provides an accurate and highly responsive regulator that can be constructed to have smaller dimensions than those available in the conventional art. More specifically, the width of the pressure regulator of the present invention may be reduced to make it thinner as compared to pressure regulators known in the related art, while still providing sufficient surface area relative to the piston so that the pressure regulator maintains its responsiveness.

Another advantage of the present invention is that by providing a pressure regulator of smaller size, the present invention can be placed on or in close proximity to the device to be regulated, thereby allowing a shortened flow path therebetween and reducing the number of associated hardware components. This simplifies the design of the pneumatic system, which can reduce cost, increase efficiency and convenience.

Drawings

Other advantages of the invention will be readily apparent and better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view of a pneumatic pressure regulator assembly of the present invention;

FIG. 2 is a cross-sectional side view of the pneumatic pressure regulator assembly of the present invention as seen with the regulator valve assembly in its open position;

FIG. 3 is a cross-sectional side view of the pneumatic pressure regulator assembly of the present invention as seen with the regulator valve assembly in its closed position;

FIG. 4 is a cross-sectional side view of the pneumatic pressure regulator assembly of the present invention as seen with the regulator valve assembly in its closed position and the bleed orifice open;

FIG. 5 is an end view of the pneumatic pressure regulator assembly of the present invention taken along line 5-5 of FIG. 4;

fig. 6 is a perspective view of the regulator piston of the present invention;

FIG. 7 is an end view of the pressure responsive surface of the regulator piston; and

fig. 8 is an end view of the regulator piston of the present invention.

Detailed Description

In fig. 1-4, the pneumatic pressure regulator assembly of the present invention is generally indicated by reference numeral 10. The pneumatic pressure regulator assembly 10 of the present invention is designed to be used as part of any number of pneumatic systems to regulate a supply pressure to a predetermined system pressure. The assembly 10 includes a regulator housing, generally indicated by reference numeral 12. The regulator housing 12 includes a main body 18 and an adjustment bonnet 20. The main body 18 is defined by a pair of side walls 22, 24 and a pair of end walls 26, 28, the end walls 26, 28 extending between the pair of side walls to define the width of the pressure regulator assembly 10. The body 18 also includes upper and lower mounting surfaces 30, 32, respectively. The adjustment bonnet 20 is mounted to the upper mounting surface 30 of the main body 18 by any conventional means. Accordingly, the adjustment bonnet 20 has similar and corresponding side and end wall structures. More specifically, the adjustment bonnet 20 includes a pair of side walls 34, 36 and a pair of end walls 38, 40 extending therebetween. The adjustment bonnet 20 also has a lower mounting surface 42 adapted to be mounted to the corresponding upper mounting surface 30 of the main body 18. Finally, as will be described in greater detail below, the adjustment bonnet 20 includes a regulator adjustment assembly, generally indicated by reference numeral 44.

As best shown in fig. 1, in the preferred embodiment, the regulator housing 12 is substantially rectangular in shape with end walls of a dimension less than the side walls thereof. This gives the housing 12 a thin shape, facilitating its use in tight spaces. Certain features of the regulator assembly 10 of the present invention contribute to this optimum shape, as will be described in detail below. However, it will be understood by those of ordinary skill in the art that the regulator housing may have any suitable geometry within the scope of the appended claims.

As best shown in fig. 2-4, the main body 18 of the regulator housing 12 supports a regulator valve assembly, generally indicated at 46, and a piston assembly, generally indicated at 48. The main body 18 of the regulator housing 12 includes an inlet 50 and at least one outlet 52. In the preferred embodiment shown in these figures, both the inlet 50 and the outlet 52 are formed through the lower mounting surface 32 of the body 18. The inlet 50 is operatively connected to a source of air pressure in a known manner. As is well known in the art, the air pressure source is at a first elevated pressure. Additionally, the regulator body 18 may also include a second outlet 54, which may be formed in the end wall 26 or 28 of the body 18, for example. The second outlet 54 may be physically connected to and in fluid communication with an external gauge or external pressure monitoring line (not shown) by any known attachment means, such as threads indicated at 56. Alternatively, the second outlet 54 may be plugged with a plug shown in phantom at 59.

The regulator valve assembly 46 is supported in the main body 18 of the regulator housing 12 between the inlet 50 and the outlet 52 and between the inlet 50 and the second outlet 54 (if used). In this way, the regulator valve assembly 46 controls the flow rate of air pressure through its regulator device 10. Accordingly, the regulator valve assembly 46 includes a valve member, generally indicated at 58, a valve biasing assembly, generally indicated at 60, and a valve retainer, generally indicated at 62. As will be described in detail below, the valve retainer 62 includes a head portion 64, a valve seat 66, and a body portion 68 extending between the head portion 64 and the valve seat 66. The valve member 58 of the regulator valve assembly 46 includes a valve stem 70 and a valve element 72. The valve stem 70 is elongated and terminates in a distal end 74. The valve element 72 defines a sealing surface 76 for purposes to be described in detail below.

As shown in fig. 2, the valve member 58 is operably disposed in the valve retainer 62 such that the valve member 58 is in its open position when the valve element 72 is spaced from the valve seat 66, thereby allowing fluid communication between the inlet 50 and the outlet 52. As shown in fig. 3, the valve sealing surface 76 is adapted to sealingly engage the valve seat 66 when the valve element 72 is in its closed position, thereby interrupting fluid communication between the inlet 50 and the outlet 52 when the downstream pressure exceeds a predetermined value. Thus, the valve retainer 62 may include one or more o-ring seals 78, the o-ring seals 78 being cooperatively received in a groove formed in the respective valve retainer 62 or in the body 18 of the regulator housing 12.

The valve biasing assembly 60 includes a biasing member 80 captured between a cup holder 82 and the body 18. The biasing member 80 serves to bias the valve element 72 against the valve seat 66 to its closed position. More specifically, when the valve member 58 is in its closed position, the valve biasing assembly 60 will act to press the sealing surface 76 of the valve member against the valve seat 66. As shown in these figures, the biasing member 80 may be a coil spring. In the preferred embodiment, the cup holder 82 is integrally formed as part of the valve member 58 opposite the distal end 74 of the valve stem 70. However, it will be appreciated by those of ordinary skill in the art that the biasing member 80 can be formed in any conventional manner and the cup-shaped retainer 82 can be formed as a separate component from the valve member 58.

The valve element 72 is formed between the valve stem 70 and the cup holder 82. In the preferred embodiment, the valve member 58 is an aluminum regulator poppet molded in place of a suitable resilient material such as rubber or any known elastomer. More specifically, it should be understood by those of ordinary skill in the art that the material of the sealing surface 76 may be made of any known composition that is slightly deformable, yet highly resilient, and that may be adhered or molded to the valve element 72. Similar to the valve retainer 62, the valve member 58 may also include one or more o-ring seals 84, the o-ring seals 84 being cooperatively received in a groove 85 formed, for example, about the circumference of the cup-shaped retainer 82 or at any other suitable location.

The head portion 64 of the valve retainer 62 includes a stepped surface, generally indicated at 86, the stepped surface 86 cooperating with a corresponding surface 88 defined in the body 18 of the regulator housing 12. The retainer 90 cooperates with the body 18 to facilitate retaining the valve retainer 62 in a fixed position. Additionally, the body portion 68 defines a valve stem passageway 92 extending therethrough. More specifically, the body portion 68 is preferably hollow and cylindrical and defines a valve stem passageway 92 through which the valve stem 70 of the valve member 58 extends. The valve member 58 cooperates with the head portion 64 of the valve retainer 62 such that the distal end 74 and a portion of the valve stem 70 operatively pass through an opening 94 in the head portion 64 of the valve retainer 62 opposite the valve seat 66. The opening 94 is slightly larger than the diameter of the valve stem 70 to allow relative movement between the valve stem 70 of the head portion 64.

The body portion 68 of the valve retainer 62 includes a plurality of flow passages 96 radially spaced from one another about the circumference of the body portion 68 of the valve retainer 62. The valve stem passage 92 and the flow passage 96 provide fluid communication between the inlet 50 and the outlet 52 of the pressure regulator assembly 10. In addition, there are a plurality of head flow passages 95 radially spaced from one another about the circumference of the head portion 64 of the valve retainer 62, the head flow passages 95 allowing fluid communication between the valve stem passage 92 and the piston bore 102 as described below.

The piston assembly 48 includes a regulator piston 98. In a preferred embodiment, the piston assembly 48 is disposed in the main body 18 and the regulator adjustment assembly 44 is disposed in the adjustment bonnet 20. More specifically, the piston assembly 48 is movably supported in the body 18 and functions to bias the valve member 58 to its open position when the downstream pressure flowing through the outlet 52 is below a predetermined value. A corresponding piston bore 102 is defined in the regulator housing 18 (as is true, whether it should be 12). The piston bore 102 opens at the upper mounting surface 30 of the body 18. The piston 98 is movably supported in the piston bore 102. A sealing member 104 is disposed about the outer circumference of the piston to facilitate an air seal between the piston 98 and the piston bore 102.

Piston assembly 48 includes a pressure responsive surface 106 that forms a geometry having a major axis "a" that is larger than a minor axis "B". In a preferred embodiment, the pressure responsive surface 106 is formed on one side of the piston 98. As such, the pressure responsive surface 106 has an elongated shape that maximizes the surface area in the thin rectangular area in the main body 18 of the regulator housing 12. As will be described in greater detail below, this configuration helps to provide an accurate and highly responsive voltage regulator 10 having smaller physical dimensions than previously available in the related art. It should be understood by one of ordinary skill in the art that the piston 98 itself may be formed in any geometric shape having a major axis "A" and a minor axis "B", wherein the major axis "A" is greater than the minor axis "B". The piston bore 102 is formed with a complementary geometry to the piston 98 and thus may also have a major axis "a" and a minor axis "B", wherein the major axis "a" is greater than the minor axis "B". In a preferred embodiment, and as best shown in fig. 6-8, the piston 98 includes elongated side walls 108 and 110, the elongated side walls 108 and 110 smoothly merging with rounded but shorter end walls 112 and 114 extending therebetween. In a preferred embodiment, the pressure responsive surface 106, wherein the major axis "A" is greater than the minor axis "B". In the preferred embodiment, the pressure responsive surface 106, the piston 98, and the piston bore 102 all define an elliptical shape. As used herein, the term "elliptical" refers to any geometric shape having a major axis greater than a minor axis and does not mean that the pressure responsive surface 106 is limited to only elliptical or parabolic shapes. Accordingly, it should be understood by those of ordinary skill in the art that the pressure responsive surface 106, the piston 98, and the piston bore 102 may comprise a variety of geometries having a major axis that is larger than a minor axis thereof without departing from the scope of the present invention.

The piston 98 also has a receptacle 116 formed on the pressure responsive surface 106 thereof, the receptacle 116 being adapted to receive the distal end 74 of the valve stem 70. As will be described in greater detail below, a bleed orifice 118 extends through the piston 98 for venting. The pneumatic pressure flowing between the inlet 50 and the outlet 52 is delivered to the pressure responsive surface 106 through the valve stem passageway 92 and the opening 94 through the head portion 64 of the valve retainer 62 as described above. This causes the piston 98 to move to the right as viewed in the figures and reduces the piston biasing force acting on the valve member 58 thereby causing the valve member 58 to move to its closed position when the downstream pressure flowing through the outlet 52 exceeds a predetermined value.

The regulator adjustment assembly 44 includes an adjustment member, generally indicated at 120, and a biasing member, generally indicated at 122, disposed between the adjustment member 120 and the piston 98. The biasing member 122 applies a selectively adjustable biasing force by moving the adjustment member 120 toward or away from the piston, wherein the adjustment corresponds to a predetermined pressure value. The piston biasing member 122 may include at least one coil spring disposed between the adjustment member 120 and the piston 98. In a preferred embodiment, the piston biasing member 122 includes a pair of coil springs 124, 126 supported in concentric and coaxial relationship with one another. The spring 124 may be referred to as an inner concentric spring. The spring 126 may be referred to as an outer concentric spring. One end 128 of the inner spring 124 is received by a corresponding shoulder 130 formed on a top edge 132 of the piston 98. Likewise, one end 128 of the outer spring 126 is received by a corresponding shoulder 136 formed on the top edge 132 of the piston 98. As described in more detail below, the respective opposite ends 138, 140 of each coil spring 124, 126 are adapted to engage the adjustment member 120.

The adjustment member 120 includes an adjustment nut 142 movably supported on a threaded adjustment rod 144 for movement toward or away from the piston 98. One end 148 of the adjustment rod 144 extends into the adjustment bonnet 20 in the concentrically arranged coil springs 124, 126. The adjustment knob 146 is disposed on the other end 150 of the adjustment rod 144 and is securely engaged with the adjustment rod 144 by known means, such as by splines or keyways generally indicated by reference numeral 152. Rotation of the adjustment knob 146 rotates the threaded adjustment rod 144, thereby moving the adjustment nut 142 toward or away from the piston 98. Thus, the adjustment nut 142 is first moved into engagement with the one end 138 of the internal coil spring 124 to apply a first level of bias to the piston 98. Further movement of the adjustment nut 142 along the rod 144 causes the nut 142 to engage one end 140 of the outer coil spring 126 to provide an auxiliary level of biasing force to the piston 98. Thus, with the two springs 124, 126 acting in combination, the biasing member 122 is adapted for use with two-stage incremental adjustments (i.e., course and fine increments), thereby providing a wide range of adjustment to the downstream pressure. It should be appreciated by those of ordinary skill in the art that the dual spring configuration of the biasing member 122 provides a greater response to a variety of changes in the pressure applied to the piston 98. It should also be appreciated that the biasing member 122 may be a single coil spring, a multiple coil spring, or any other biasing member known in the relevant art as may be specifically contemplated by the present application without departing from the spirit or scope of the present invention.

The regulator adjustment assembly 44 also includes a locking screw 156. The locking screw 156 is threadably engaged in the end of the adjustment rod 144, thereby securely holding the entire adjustment assembly 44 in place when the locking screw 156 is tightened. When the locking screw 156 is loosened, the adjustment knob 146 is free to rotate and the biasing force applied to the piston 98 is adjusted by rotation of the adjustment nut 142 along the length of the adjustment rod 144, either increasing or decreasing the pressure applied to the biasing member 122 as described above.

Operation of

In operation, it will be appreciated that the pressure regulator assembly 10 will be in fluid communication with a source of air pressure through the inlet 50 and will be in communication with the determining means through the outlet 52. The operator can optionally select a predetermined regulated air pressure to be output by the regulator assembly 10 of the present invention to the downstream active device. The locking screw 156 is loosened and the adjustment knob 146 is turned to achieve a particular biasing force on the piston 98. When the distal end 74 of the valve stem 70 is received in the receptacle 116, the biasing force exerted by the biasing member 122 on the piston 98 acts through the distal end 74 of the valve stem 70. To the extent that this force exceeds the biasing force of the valve biasing member 80, it causes the valve member 58 to move to its open position. This causes the supplied air pressure to move from the inlet 50, through the valve element 72 and the valve seat 66, into the valve retainer 62, through the plurality of flow passages 96 and through the outlet 52, to the pneumatic device (not shown). An external pressure gauge, for example, is operatively connected through the second outlet 54 to monitor the downstream pressure of the two outlets 52.

Typically, the system pressure is delivered at a pressure higher than desired for operation of the active device. Therefore, the pressure regulator 10 must reduce or "regulate" the excess supply pressure to a predetermined value selected by the operator. Thus, the biasing force selected by operation of the adjustment assembly 44 correlates to the counter-balancing air pressure level of the piston 98 acting on the pressure responsive surface 106 through the valve stem passageway 92.

In particular, when the downstream pressure exceeds a specified desired regulated pressure level, as set by the biasing force exerted on the piston 98 by the biasing member 122, the excess downstream pressure will return from the outlet 50 through the plurality of flow passages 96 of the retainer 62 into the valve stem passage 92 and through the plurality of head flow passages 95 in the head portion 64 of the valve retainer 62, opposite the pressure responsive surface 106 of the piston 98. This pressure, in combination with the biasing force created by the valve biasing member 60, causes the piston 98 to move to the right as viewed in FIG. 3. When the piston 98 is moved sufficiently to the right, the valve element 72 is caused to move to its closed position, where the sealing surface 76 seats against the valve seat 66. When the valve element 72 is closed, the flow of air pressure between the inlet 50 and the outlet 52 is interrupted.

As best shown in fig. 4, if any excess pressure remains or returns from the outlet 52, the piston 98 will continue to be pushed back against the biasing force exerted by the piston biasing member 122 to expose the bleed orifice 118 through the piston 98, thereby allowing additional pressure to bleed through the regulator cap 20. This condition will continue to cause a pressure drop or fluctuation downstream of the mourning. This condition can be maintained indefinitely if the pneumatic device does not use regulated pressure and does not leak, creating a pressure balance. On the other hand, this condition may be immediate if the pneumatic device is running downstream and using the regulated pressure provided by the present invention.

When the supplied regulated pressure is used and the air pressure acting on the responsive surface of the piston 98 falls below a predetermined value, the piston biasing member 122 will again automatically move the piston 98 such that the valve member 58 moves to its open position (fig. 2), reestablishing fluid communication between the inlet and outlet ports.

In this manner, it will be appreciated by those skilled in the art that the present invention provides unique advantages over the prior art. More specifically, the present invention is embodied in a regulator housing 12 having a substantially reduced width as compared to the related art while maintaining a pressure responsive surface 106 on the piston 98 with a sufficiently large carrier surface area to provide an accurate and highly responsive regulator 10. This configuration helps to provide regulator 10 with a smaller size than those available in the conventional art. Moreover, by providing a pressure regulator 10 of smaller size, the present invention may be placed on or in close proximity to any device to be regulated, thereby enabling a shortened flow path therebetween and reducing the number of associated hardware components. This simplifies the design of the pneumatic system, which can reduce cost, increase efficiency and convenience.

The invention has been described by way of example. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. Accordingly, within the scope of the appended claims, the invention may be practiced other than as specifically defined.

Claims (20)

1. A pneumatic pressure regulator assembly (10) comprising:

a regulator housing (12), the regulator housing (12) having: an inlet (50) adapted to be in fluid communication with a source of pneumatic pressure at a first elevated pressure; at least one outlet (52) adapted to provide pneumatic pressure to at least one downstream pneumatic device at a second, lower regulated pressure;

a regulator valve assembly (46), said regulator valve assembly (46) having a valve member (58) movably supported in a regulator housing (12) between an open position and a closed position; and

a piston assembly (48), said piston assembly (48) being movably supported in said regulator housing (12) and serving to bias said valve member (58) to its open position when the downstream pressure flowing through said outlet (52) is below a predetermined value, said piston assembly (48) including a pressure responsive surface (106) forming a geometry having a major axis a and a minor axis B, wherein the major axis is greater than the minor axis, said piston assembly (48) being responsive to air pressure flowing between said inlet (50) and said outlet (52) to reduce the biasing force acting on the valve member (58) to move the valve member to its closed position when the downstream pressure flowing through said outlet (52) exceeds the predetermined value.

2. A pneumatic pressure regulating assembly (10) as set forth in claim 1 wherein said piston assembly (48) includes a piston (98) formed in a geometry having a major axis a and a minor axis B wherein the major axis is greater than the minor axis.

3. A pneumatic pressure regulating assembly (10) as set forth in claim 2 further comprising a piston bore (102) defined in said regulator housing (12), said piston (98) being movably supported in said piston bore (102), said piston bore (102) defining a complementary geometry to said piston (98) and having a major axis and a minor axis, wherein the major axis is greater than the minor axis.

4. A pneumatic pressure regulating assembly (10) as set forth in claim 3 wherein said piston (98) and said piston bore (102) are formed in an elliptical shape.

5. A pneumatic pressure regulating assembly (10) as set forth in claim 1 wherein said valve member (58) has a valve element (72) and a valve stem (70) with said valve element (72) having a valve sealing surface (76) and said valve stem (70) having a distal end (74) opposite said valve element (72).

6. A pneumatic pressure regulating assembly (10) as set forth in claim 5 wherein said regulator housing (12) includes a valve retainer (62), said valve retainer (62) having a valve seat (66), a head portion (64), and a body portion (68) extending therebetween, said body portion (68) defining a valve stem passage (92) and including a plurality of flow passages (96) spaced radially relative to one another about the body portion (68), said plurality of flow passages (96) providing fluid communication between said outlet (52) and said valve stem passage (92).

7. A pneumatic pressure regulating assembly (10) as set forth in claim 6 wherein said valve member (58) is movably supported relative to a valve retainer (62) such that said valve member (58) is in its open position when said valve sealing surface (76) of the valve element (72) is spaced from said valve seat (66) to permit fluid communication between said inlet (50) and said outlet (52), said valve member (58) being adapted to sealingly engage said valve seat (66) when said valve element (72) is in its closed position to interrupt fluid communication between said inlet (50) and said outlet (52) when the downstream pressure exceeds a predetermined value.

8. A pneumatic pressure regulating assembly (10) as set forth in claim 7 wherein said valve stem (70) is received by said valve stem passage (92), said valve stem passage (92) of said valve retainer (62) having an inner diameter greater than an outer diameter of said valve stem (70) such that said valve stem passage (92) is adapted to allow air pressure to pass through said valve stem passage (92) around said valve stem.

9. A pneumatic pressure regulating assembly (10) as set forth in claim 6 wherein said head portion (64) of said valve retainer (62) includes an opening (94) extending therethrough, said valve stem (70) extending through said opening (94) such that said distal end (74) of said valve stem (70) is in contact with said piston assembly (48), said distal end (74) of said valve stem (70) serving to transfer a biasing force from said piston assembly (48) to move said valve element (72) to its open position such that said valve sealing surface (76) of said valve element (72) is spaced from said valve seat (66).

10. A pneumatic pressure regulating assembly (10) as set forth in claim 9 wherein said piston assembly (48) has a piston (98), said piston (98) including a receptacle (116), said receptacle (116) being adapted to receive said distal end (74) of said valve stem (70).

11. A pneumatic pressure regulating assembly (10) as set forth in claim 10 wherein said piston (98) includes a bleed orifice (118) extending therethrough, said bleed orifice (118) being closable by said distal end (74) of said valve stem (70) when said valve member (58) is in the open position, said bleed orifice (118) being openable when said valve member (58) is moved to its closed position.

12. A pneumatic pressure regulating assembly (10) as set forth in claim 6 wherein said valve member (58) is an aluminum poppet valve and said valve sealing surface (76) of said valve element (72) is overmolded with a resilient material at the point where said valve member (58) engages said valve seat (66).

13. A pneumatic pressure regulating assembly (10) as set forth in claim 5 wherein said regulator valve assembly (46) further includes a valve biasing assembly (60), said valve biasing assembly (60) having a cup-shaped retainer (82) in contact with said valve element (72) and a valve biasing member (80) disposed between said regulator housing (12) and said cup-shaped retainer (82), said valve biasing member (80) being operable to bias said valve member (58) to its closed position by applying a biasing force between said regulator housing (12) and said cup-shaped retainer (82).

14. A pneumatic pressure regulating assembly (10) as set forth in claim 13 wherein said valve biasing member (80) includes at least one coil spring.

15. A pneumatic pressure regulating assembly (10) as set forth in claim 10 further comprising a regulator adjustment assembly (44), said regulator adjustment assembly (44) including a piston biasing member (122), said piston biasing member (122) exerting a biasing force on said piston (98) to bias said valve member (58) to its open position.

16. A pneumatic pressure regulating assembly (10) as set forth in claim 15 wherein said regulator adjustment assembly (44) includes an adjustment member (120), said piston biasing member (122) being disposed between said adjustment member (120) and said piston (98) such that the biasing force exerted by said piston biasing member (122) is selectively adjustable by moving said adjustment member (120) toward or away from said piston (98) to effect adjustment of the biasing force corresponding to a predetermined pressure value.

17. A pneumatic pressure regulating assembly (10) as set forth in claim 16 wherein said piston biasing member (122) includes at least one coil spring (124, 126) disposed between said adjustment member (120) and said piston (98).

18. A pneumatic pressure regulating assembly (10) as set forth in claim 16 wherein said piston biasing member (122) includes a plurality of coil springs (124, 126) supported in concentric and coaxial relationship with one another between said adjustment member (120) and said piston (98).

19. A pneumatic pressure regulating assembly (10) as set forth in claim 15 wherein said regulator adjustment assembly (44) includes a threaded adjustment rod (144) and an adjustment nut (142) threadably supported on said adjustment rod (144) for movement toward or away from a piston (98), said piston biasing member (122) being disposed between said piston (98) and said nut (142).

20. A pneumatic pressure regulating assembly (10) as set forth in claim 19 wherein said regulator adjustment assembly (44) includes an adjustment knob (146) connected to said adjustment rod (144) such that rotation of the adjustment knob (146) rotates the threaded adjustment rod (144) to move the adjustment knob (146) toward or away from the piston (98).