Abstract:
A gas pressure regulator capable of minimizing vibration and improving overall fluid flow efficiency. The gas pressure regulator achieves these benefits using varying techniques including providing a nozzle having a primary passage, a secondary passage, and a flow channel groove to smooth the fluid flow, reduce turbulence, and improve overall flowrate, without adversely effecting the necessary backpressure required for reliable operation. Additionally, the gas pressure regulator may use angled walls in the low-pressure cavity to enhance deflection and distribution. Still further, the gas pressure regulator may use additional flow channels to permit smooth fluid flow while eliminating fluid impact.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention generally relates to gas pressure regulators and, more particularly, relates to a gas pressure regulator capable of decreasing internal vibration and increasing flow efficiency therethrough to provide improved flow performance.  
       BACKGROUND OF THE INVENTION  
       [0002]     In many situations, gas pressure regulators are used to control and/or maintain a desired fluid flow and pressure for use in operating a wide variety of machines, devices, and the like. In this regard, it is desirable for gas pressure regulators to provide a stable and consistent fluid flow rate and/or fluid pressure so as not to hinder the operation of or damage downstream machines or devices. Unfortunately, many conventional gas pressure regulators suffer from various disadvantages that may lead to encumbered operation, such as internal vibration or decrease flow efficiency.  
         [0003]     Conventional gas pressure regulators generally include a valve assembly that is selectively and automatically actuated to maintain a desired set pressure in response to a downstream pressure. This is typically achieved using an adjusting spring that applies a pressure to a spool member of a valve assembly. The adjusting spring is set by an operator via an adjusting knob to a predetermined biasing force. Once an internal fluid pressure, acting on a diaphragm member, overcomes this predetermined biasing force, the valve assembly is closed. As fluid is consumed by the work device, the pressure within the low-pressure cavity drops, which starts the cycle to continue again—the diaphragm moving up and down, opening and closing the seat, to maintain a constant pressure within the regulator based on the load applied by turning the adjusting knob.  
         [0004]     However, conventional gas pressure regulators suffer from a number of disadvantages. For example, as flow rate needs increase, the valve assembly, namely the valve seat, will open further in reaction to the diaphragm dropping more and more as it attempts to compensate for increased pressure loss: in the low-pressure cavity. When this happens, the adjusting spring correspondingly decompresses, since its length is now increasing as the diaphragm lowers with respect to a stationary adjusting knob position. As its length increases, the force it applies to the top of the diaphragm decreases, at a rate determined by the spring rate of the adjusting spring. This force balances the forces in the regulator to achieve a desired delivery pressure and, consequently, causes the delivery pressure out of the regulator to drop as flow rate increases. This effect is illustrated in  FIG. 7 . With reference to  FIG. 7 , it can be seen that with an initial pressure setting of the regulator of 125 PSIG, at maximum flow rate, (i.e. 2500 SCFH), the outlet pressure decreases about 100 PSIG. This is the nature of most conventional gas pressure regulators. It is generally understood in the art that a “flatter” or level curve is most desirable as it indicates a more uniform delivery pressure between zero flow and max flow. Therefore, since the pressure rapidly exiting the gas regulator is causing the diaphragm to drop (which causes delivery pressure to drop), then the faster the valve assembly can take the inlet pressure and fill the low-pressure cavity, the faster the regulator can keep up with the flow demands and therefore, the less the diaphragm will drop to compensate. If the diaphragm does not need to drop as much to compensate, then this means that the adjusting spring is unloading less, and therefore the delivery pressure is staying more constant.  
         [0005]     However, while speeding things up inside the regulator can make it perform better, it can also increase turbulence and vibration—two of the biggest problems in pressure regulation.  
         [0006]     Turbulence is often caused when the increased flow rate demands turn the velocity of the flow inside the regulator supersonic in various key areas—at the valve seat itself, where the high inlet pressure drops rapidly; through the nozzle (including the nozzle outlet holes); and through the outlet holes of the low-pressure cavity. With this increase in velocity also comes an increase in turbulence—not only at the nozzle/seat area, but also inside the low-pressure cavity, as the high velocity stream coming out of the nozzle hole is diffused into the larger cavity area. This turbulence, regardless of its origin, can have negative impacts on the regulator performance—it can not only decrease efficiency of the regulator, slowing the gas flow down, but more importantly, it can also cause vibration inside the regulator.  
         [0007]     Vibration can also lead to disadvantageous operation of gas pressure regulators. When the regulator is in a flowing state, the contact point between the stem of the valve assembly and the diaphragm is “floating” on two springs—the adjusting spring controlling the position of the diaphragm, and the valve spring controlling the position of the spool member and stem. Vibration from the seat area (the contact between the spool member and the sealing surface) or vibration applied against the bottom side of the diaphragm will translate directly into this floating contact point. Additionally, the nature of springs serves to amplify the effects of vibration—especially if the frequency of the vibration is near (or the same as) the natural harmonic frequency of either spring. Friction dampening devices have been used in an attempt to overcome the vibration, but their use dampens the reaction performance and flexibility of the diaphragm leading to sluggish performance and decreased consistency.  
         [0008]     Vibration can get unmanageable if the diaphragm and the stem vibrate at such a rate that they can no longer vibrate together, at the same frequency, and therefore lose contact with each other and vibrate independently. The term “singing” is widely used in the industry to describe when this happens. When the diaphragm and stem lose contact with each other and vibrate independently, they will slam into each other at the rate of their vibration and create a violent high frequency buzzing sound. When a regulator sings, the action is usually violent enough to cause internal damage to the regulator. Most notably, the seat itself will be damaged from the repeated high frequency impact and may cause the regulator to leak. This vibration can also travel along the fluid downstream to a work device.  
       SUMMARY OF THE INVENTION  
       [0009]     According to the principles of the present invention, a gas pressure regulator having an advantageous construction and a method of using the same is provided, which may find utility in a wide variety of applications. The gas pressure regulator of the present invention is capable of minimizing vibration and improving overall fluid flow efficiency. The gas pressure regulator achieves these benefits by varying techniques including providing a nozzle having a primary passage, a secondary passage, and a flow control groove to smooth the fluid flow, reduce turbulence, and improve overall flowrate, without adversely affecting the necessary backpressure required for reliable operation. Additionally, the gas pressure regulator may use angled walls in the low-pressure cavity to enhance deflection and distribution. Still further, the gas pressure regulator may use additional flow channels to permit smooth fluid flow while eliminating fluid impact.  
         [0010]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0012]      FIG. 1  is a perspective view illustrating a gas pressure regulator incorporating the principles of the present invention;  
         [0013]      FIG. 2  is a cross-sectional view illustrating the gas pressure regulator according to the present invention;  
         [0014]      FIG. 3  is an enlarged perspective view illustrating a nozzle of the present invention with portions shown hidden;  
         [0015]      FIG. 4 ( a ) is a cross-sectional view illustrating the gas pressure regulator having a primary passageway according to the present invention;  
         [0016]      FIG. 4 ( b ) is a cross-sectional view illustrating the gas pressure regulator having a primary passageway and a secondary passageway according to the present invention;  
         [0017]      FIG. 4 ( c ) is a cross-sectional view illustrating the gas pressure regulator having a primary passage, secondary passage, and flow channel groove according to the present invention;  
         [0018]      FIG. 5  is an enlarged cross-sectional view illustrating a portion of the gas pressure regulator;  
         [0019]      FIG. 6 ( a ) is an enlarged perspective view illustrating a base portion of the regulator body having one discharge channel with portions shown hidden;  
         [0020]      FIG. 6 ( b ) is an enlarged perspective view illustrating a base portion of the regulator body having a pair of discharge channels with portions shown hidden;  
         [0021]      FIG. 7  is a graph illustrating delivery pressure of a conventional gas pressure regulator;  
         [0022]      FIG. 8  is a cross-sectional view illustrating an alternative embodiment of the gas pressure regulator having a primary passage and secondary passage disposed parallel to a longitudinal axis of the nozzle; and  
         [0023]      FIG. 9  is a cross-sectional view illustrating an alternative embodiment of the gas pressure regulator having a primary passage and secondary passage disposed orthogonal to a longitudinal axis of the nozzle. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0024]     The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0025]     Referring now to the drawings in which like reference numerals designate like or corresponding parts throughout the several views, a gas pressure regulator, generally indicated as  10 , is illustrated incorporating the principles of the present invention. As seen in  FIG. 1 , gas pressure regulator  10  may be used in conjunction with a pair of pressure gauges for displaying an inlet and an outlet pressure.  
         [0026]     Referring now to  FIG. 2 , gas pressure regulator  10  generally includes a regulator body  12 . Regulator body  12  includes a base portion  14  and an upper portion  16 . Upper portion  16  of regulator body  12  defines a threaded locking flange  18  adapted to threadedly engage corresponding threads  20  formed on base portion  14  of regulator body  12  to permit reliable and simple coupling of base portion  14  and upper portion  16 .  
         [0027]     Base portion  14  of regulator body  12  defines a longitudinally extending valve bore  22 . Similarly, upper portion  16  of regulator body  12  defines a longitudinally extending spring bore  24 . Valve bore  22  fluidly communicates with an inlet port  26 . Inlet port  26  is adapted to be connected with a source of compressed fluid, such as air. Valve bore  22  further fluidly communicates indirectly with an outlet port  30 . The specific configuration and arrangement of such fluid communication between valve bore  22  and outlet port  30  will be described in detail below. Outlet port  30  is adapted to be connected with a load line of a fluid operated device or machine. Base portion  14  of regulator body  12  further includes a plurality of optional mounting apertures  34  adapted to receive fasteners (not shown) therein for mounting.  
         [0028]     Referring to  FIG. 5 , valve bore  22  of base portion  14  is generally sized to receive a valve assembly  36 . Valve assembly  36  includes a spool member  38  contained within a valve cup  40 . Valve cup  40  includes a first half  42  and a second half  44 . First half  42  of valve cup  40  includes a flange  46  adapted to engage, such as through crimping, a peripheral edge  50  of second half  44  to prevent relative movement of first half  42  and second half  44 . Second half  44  is generally cup shaped having an internal volume  52  sized to receive a spindle member  54  therein. Spindle member  54  includes a cylindrical portion  56  terminating at and integrally formed with a head portion  58 . Head portion  58  rests upon an interior base surface  60  of second half  44  of valve cup  40 .  
         [0029]     Still referring to  FIG. 5 , cylindrical portion  56  of spindle member  54  is sized to slidably receive a pin  62  of spool member  38 . Spool member  38  is biased apart from spindle member  54  via a valve spring  64 . At one end, valve spring  64  engages head portion  58  of spindle member  54 . At an opposing end, valve spring  64  engages a shoulder portion  66  of spool member  38 . Shoulder portion  66  of spool member  38  is slidably received within internal volume  68  of first half  42  of valve cup  40 .  
         [0030]     Referring to  FIG. 5 , spool member  38  further includes a nose portion  70  extending outward from shoulder portion  66 . Nose portion  70  is generally coaxial with a longitudinal axis of spool member  38 . Nose portion  70  is sized to seat against a seal insert or seat  72  to selectively provide a fluid seal therebetween. That is, when nose portion  70  of spool member  38  is seated against seal insert  72 , a fluid seal is defined that prevents fluid from passing through a port  73  ( FIG. 4 ( a )) between inlet port  26  and outlet port  30 . When nose portion  70  of spool member  38  is spaced apart from seal insert  72 , the fluid seal is broken and fluid passes through port  73  between inlet port  26  and outlet port  30 . Seal insert  72  is disposed within a depression  74  formed in first half  42  of valve cup  40 . Seal insert  72  is retained within depression  74  between a flange  76  and a nozzle  78 , which will be described further below.  
         [0031]     As best seen in  FIGS. 2, 3 , and  5 , nozzle  78  includes a flange  80  circumferentially extending about a lower portion of nozzle  78 . Flange  80  includes a threaded portion  82  disposed about an exterior surface  84  of flange  80  to threadedly engage a corresponding set of threads  86  extending about valve bore  22  of base portion  14 . In this regard, nozzle  78  is threadedly coupled to base portion  14  and further serves to capture seal insert  72  between flange  76  and nozzle  78 .  
         [0032]     As best seen in  FIGS. 3 and 4 ( a )-( c ), nozzle  78  further includes a nozzle cavity  88 , a primary passageway  90 , and a secondary passageway  92 . Nozzle cavity  88  extends between port  73  and primary passageway  90  and secondary passageway  92  to define a fluid path from port  73  to both primary passageway  90  and secondary passageway  92 . Nozzle cavity  88  terminates at an inclined ceiling  94 . Inclined ceiling  94  includes a bore  96  sized to slidably receive a stem member  98  therethrough. Stem member  98  extends from bore  96  of nozzle  78 , through nozzle cavity  88  and is received within a bore  100  formed through nose portion  70  of spool member  38 . Stem member  98  serves to first define an engagable connection between spool member  38  and a diaphragm member  108  (described below). Additionally, stem member  98  serves to maintain axial alignment of spool member  38  relative to nozzle  78  and seal insert  72 .  
         [0033]     Primary passageway  90  is disposed within nozzle  78  at an angle a inclined relative to a longitudinal axis of nozzle cavity  88 . Similarly, secondary passageway  92  is disposed within nozzle  78  at an angle β inclined relative to the longitudinal axis of nozzle cavity  88 . Preferably, secondary passageway  92  is disposed within nozzle  78  in a higher position (as seen in the figures) or, in other words, at a position downstream from primary passageway  90 . Furthermore, it is preferable that the internal diameter of secondary passageway  92  is smaller than the internal diameter of primary passageway  90 . Both primary passageway  90  and secondary passageway  92  define fluid communication paths between nozzle cavity  88  and a low-pressure cavity  101  ( FIG. 5 ). The specifics of low-pressure cavity  101  will be described in detail below. However, it should be understood that primary passageway  90  and secondary passageway  92  may be disposed at any angle relative to the longitudinal axis of nozzle cavity  88 . For example, as seen in  FIGS. 8 and 9 , primary passageway  90  and secondary passageway  92  may be disposed at any orientation ranging from parallel to the longitudinal axis of nozzle cavity  88  ( FIG. 8 ) to orthogonal to the longitudinal axis of nozzle cavity  88  ( FIG. 9 ). Additionally, nozzle cavity  88  may be of any shape conducive to fluid flow (see  FIG. 8 ). Still further, it should be understood that primary passageway  90  and secondary passageway  92  may have any cross sectional profile, including rectangular, oval, triangular, etc.  
         [0034]     Still further, it is preferable that nozzle cavity  88  includes a flow channel groove  102  from therein. As best seen in  FIGS. 3 and 4 ( c ), flow channel groove  102  is provided such that it defines a recess or notch formed along a sidewall of nozzle cavity  88 . It has been found that flow channel groove  102  serves to minimize the presence of turbulent swirls in the fluid flow traveling through nozzle cavity  88 . Flow channel groove  102  can be easily formed by drilling primary passageway  90  deep enough to engage the opposing wall of nozzle cavity  88 . In this regard, a groove is formed to provide the enhanced flow control.  
         [0035]     Turning now to FIGS.  4 ( a )-( c ), a comparison of flow patterns is illustrated. However, it is believed that a brief background on the use of backpressure in regulators is useful.  
         [0036]     In regulators, backpressure is an important characteristic in the overall design. The existence of backpressure serves to help prevent “fluttering.” However, too much backpressure chokes the through flow performance. Without backpressure, the velocity of gas exiting is so fast and the pressure drop so great that the seat simply cannot keep up. This causes the pressure in the low-pressure cavity  101  (to be described below) to drop too fast, and therefore will cause the seat to overcompensate and open too far. Then, since it is open too far, it will cause too much pressure to get past the seat, thereby pushing diaphragm member  108  ( FIG. 2 ) up causing the seat to close quickly. This cycling motion can happen very fast, causing vibration in irregular spasms, or flutter. Therefore, the addition of backpressure creates an intermediate pressure inside the nozzle cavity. This intermediate pressure acts as a buffer zone to help smooth out the movements of the seat as it regulates pressure. Backpressure is thus desirable to an extent and is often created by causing or using a restriction in the fluid flow path. This is physically the only way to increase pressure to create this buffer zone. This restriction, however, will tend to negatively affect the flow by causing turbulent swirls. These turbulent swirls can spiral down the length of the nozzle cavity and impact the top of the high velocity flow stream coming across the seat. If this happens, the frequency of the turbulent swirls will cause vibration within the valve assembly itself, which will carry throughout the rest of the regulator and, if severe enough, could result in “singing.” In addition, because this vibration is not being caused by the springs themselves, friction-dampening devices may not be able to prevent or even dampen it.  
         [0037]     The present invention, thus, serves to straighten the fluid flow inside nozzle cavity  88 , thereby allowing a backpressure to be maintained, but minimizing the harmful vibration effects of turbulent swirls. The present invention does this using primary passageway  90 , secondary passageway  92 , and flow channel groove  102 . Primary passageway  90 , being larger, is the primary flow path for the fluid. The secondary passageway  92 , being much smaller and located above primary passageway  90 , allows backpressure to build up inside nozzle cavity  88 , while at the same time venting this backpressure to low-pressure cavity  101  thereby giving the turbulent swirls an outlet. This prevents the turbulent swirls from swirling back down onto the top of the high velocity stream coming off the seat (see  FIG. 4 ). This is more readily seen in FIGS.  4 ( a )-( c ).  
         [0038]     With initial reference to  FIG. 4 ( a ), a nozzle  78 ′ having only a primary passageway  90 ′ is illustrated. As can been seen, a high velocity fluid stream  500  pasts between nose portion  70  of spool member  38  and seal insert  72  and travels up a nozzle cavity  88 ′. This high velocity fluid stream  500  impacts inclined ceiling  94 ′ and is deflected back down in a turbulent flow  502 . This turbulent flow  502  swirls and impacts the high velocity fluid stream  500 , leading to further turbulent flow and the formation of a bulging effect, generally referenced at  504 . This bulging effect  504  translates to a flow stream vibration in nozzle  78 ′ that both degrades the performance of nozzle  78 ′, but also limits the flowrate at outlet port  30 .  
         [0039]     With reference to  FIG. 4 ( b ), a nozzle  78 ″ having both primary passageway  90  and secondary passageway  92  (but no flow channel groove  102 ) is illustrated. As can be seen, high velocity fluid stream  500  pasts between nose portion  70  of spool member  38  and seal insert  72  and travels up a nozzle cavity  88 ″. This high velocity fluid stream  500  impacts inclined ceiling  94 ′ and is deflected back down in a turbulent flow  502 ′. The turbulent flow swirls of  502 ′, similar to the turbulent flow swirls of  502 , lead to the formation of a bulging effect, generally referenced as  504 ″. However, when comparing nozzle  78 ″ with nozzle  78 ′, illustrated in  FIG. 4 ( a ), it can be seen that bulging effect  504 ″ of nozzle  78 ″ is considerably smaller than bulging effect  504 ′ of nozzle  78 ′. This is a result of the presence of secondary passageway  92 , which serves to relieve some of the turbulent flow or otherwise partially “vent” the flow within nozzle cavity  88 ″. The reduction of bulging effect  504 ′ reduces the flow stream vibration seen in nozzle  78 ′. The smaller diameter of secondary passageway  92 , however, continues to maintain the proper backpressure for desired performance.  
         [0040]     With reference to  FIG. 4 ( c ), a nozzle  78  having primary passageway  90 , secondary passageway  92 , and flow channel groove  102  is illustrated. As can be seen, high velocity fluid stream  500  pasts between nose portion  70  of spool member  38  and seal insert  72  and travels up nozzle cavity  88 . Secondary passageway  92  cannot stop all of the harmful turbulent flow though, since it must be sized smaller than primary passageway  90  in order to create backpressure. Consequently, flow channel groove  102  serves to further reduce any turbulent flow. Any turbulent flow that swirls down towards high velocity stream  500  is further dissipated via flow channel groove  102 . Flow channel groove  102 , positioned just above high velocity stream  500  coming off port  73 , creates a channel of increased area within nozzle cavity  88 . When the turbulent flow comes down towards high velocity stream  500 , this turbulent flow contacts the increased area of flow channel groove  102  causing the velocity of this turbulent flow to decrease, which leads to increased pressure as described by the Continuity Equation. This “wall” of high velocity stream  500  being positioned adjacent the slower moving, higher pressure downward flow near flow channel groove  102  causes the fluid flow to follow the path of least resistance-namely, along flow channel groove  102 . As the flow within flow channel groove  102  continues toward the outer edges of flow channel groove  102  near primary passageway  90 , it is then influenced by the large volume fluid flow traveling out primary passageway  90 . This arrangement creates a siphoning effect on this turbulent flow, thereby carrying it out primary passageway  90  with the rest of the flow stream. The result is that the harmful downward turbulent flow has now been rerouted and guided out through primary passageway  90 , thus eliminating any influence it might have had against high velocity flow stream  500 .  
         [0041]     In other words, the present invention reduces turbulence within nozzle cavity  88  by straightening high velocity flow stream  500 , thereby increasing efficiency, and thereby increasing overall performance. Additionally, this straightening of high velocity flow stream  500  further decreases vibration, thereby leading to improved stability of gas pressure regulator  10  and improved pressure delivery consistency.  
         [0042]     Turning now to  FIGS. 3 and 5 , low-pressure cavity  101  is illustrated, which further reduces vibration and improves regulator efficiency. As can be seen from the illustrations, low-pressure cavity  101  is defined along a lower edge by exterior surface  104  of nozzle  78 , an interior bore  106  ( FIG. 2 ) of base portion  14 , and a diaphragm member  108 . Diaphragm member  108  is received between and held in place by a clamping force of base portion  14  and upper portion  16  of regulator body  12 .  
         [0043]     Referring to  FIG. 2 , diaphragm member  108  is preferably a flexible member. Pressure is applied to a top surface of diaphragm member  108  through an adjusting mechanism  110 . Specifically, adjusting mechanism includes an adjustment knob assembly  112  threadedly coupled to upper portion  16  of regulator body  12 . Adjustment knob assembly  112  is adapted to be twisted by an operator to set a desired outlet pressure of gas pressure regulator  10 . As adjustment knob assembly  112  is actuated/twisted, an adjustment knob stem  114  engages a spring plate  116 , which applies a force against a spring member  118 . Spring member  118 , disposed within spring bore  24 , consequently applies a countering force against a pressure plate  120 , which engages diaphragm member  108 . Thus, actuation of adjustment knob assembly  112  can be used to apply or remove a pressure against diaphragm member  108 . Diaphragm member  108  is driven down in response to this pressure and contacts an end  122  ( FIG. 4 ( c )) of stem member  98  extending upward from spool member  38 . Further movement of diaphragm member  108  causes stem member  98  to drive spool member  38  downward (in the figures) against the biasing force of valve spring  64  to off-seat nose portion  70  of spool member  38  from seal insert  72 , thereby opening port  73  and permitting high velocity fluid stream  500  to pass therethrough and flow into nozzle cavity  88  and into low-pressure cavity  101  as described above. As fluid pressure within low-pressure cavity  101  increases, the opposing force acting upon diaphragm member  108  overcomes the biasing force of spring member  118  and drives diaphragm member  108  away from stem member  98 . Consequently, valve spring  64  urges spool member  38  upward and again seats nose portion  70  into sealing engagement with seal insert  72 , thereby closing port  73 . Fluid within low-pressure cavity  101  may then exit through discharge channels  124  and outlet port  30 .  
         [0044]     Low-pressure cavity  101  is particularly shaped to decrease vibration and improve efficiency. As with the nozzle backpressure discussion above, a similar principle holds true for diaphragm member  108 . A certain amount of backpressure should be maintained under diaphragm member  108 . This backpressure is the delivery pressure of gas pressure regulator  10  and is shown on a delivery pressure gauge. The key to achieving the highest performance of gas pressure regulator  10  is to maximize the flowrate of high velocity stream  500 . In this regard, the high flowrate is capable of delivering a high throughput in response to increased downstream load (i.e. a machine or work device). The key to delivering this high throughput is to quickly and efficiently slow down high velocity stream  500 , diffuse it, and distribute it evenly through low-pressure cavity  101 . If high velocity stream  500  is not evenly distributed throughout low-pressure cavity  101 , this causes a force imbalance under diaphragm member  108 , which may lead to diaphragm flutter. Furthermore, if the fluid streams exiting primary passageway  90  and secondary passageway  92  are excessively turbulent, then this turbulence may also lead to diaphragm flutter.  
         [0045]     In order to achieve the best diffusion possible within low-pressure cavity  101 , the shape of low-pressure cavity  101  preferably serves to deflect and distribute the entering fluid flow. To this end, low-pressure cavity  101  includes a first deflecting surface  200  being primarily diaphragm member  108  and its contour over a nub portion  202  formed along an underside of pressure plate  120 . Flow from primary passageway  90  and secondary passageway  92  contacts first deflecting surface  200  and is deflected outwardly to a plurality of angled surfaces  204 , generally arranged in a convex pattern, formed along interior bore  106  of base portion  14 . As can be seen by the flow arrows in  FIG. 5 , the flow is further deflected from the plurality of angled surfaces  204  into a multitude of directions (or in other words, a fan shaped pattern) to slow the flow, deflect it, and diffuse it to achieve a generally uniform distribution. Ideally, primary passageway  90  is positioned at a side opposite of discharge channels  124  to promote further this diffusion; however, this is not required.  
         [0046]     As best seen in FIGS.  6 ( a )-( b ), discharge channels  124  are further designed to enhance the smooth fluid flow, improve efficiency, and reduce vibration. Although the present invention may be used with a single discharge channel  124  (see  FIG. 6 ( a )), it is most desirable to have a pair of discharge channels  124 ′ disposed generally tangent to outlet port  30 . The pair of discharge channels  124 ′ may be of smaller diameter than single discharge channel  124 . Typically, a single centered hole creates a high impact flow area coming out of low-pressure cavity  101 , as illustrated in  FIG. 6 ( a ). This impact causes vibration, which is carried both downstream to the work device and upstream to the regulator. By using the pair of discharge channels  124 ′, together with their offset and tangential arrangement, this impact is eliminated or, at least, minimized. The flow follows the pair of discharge channels  124 ′ from low-pressure cavity  101 , swirls along the sides of outlet port  30 , and blends smoothly, without impact.  
         [0047]     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.