Abstract:
A pressure regulator having a disc spring. The pressure regulator comprises a valve having a movable device that is positioned to control fluid flow through the pressure regulator. Downstream fluid pressure produces a first force acting on the movable device to close the valve to block fluid flow through the pressure regulator. The disc spring produces a second force that acts on the movable device to open the valve to enable fluid to flow through the pressure regulator.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to pressure regulators, and particularly to a pressure regulator having a disc spring for controlling fluid pressure. 
     BACKGROUND OF THE INVENTION 
     Pressure regulators are typically used in fluid systems to regulate a flow of fluid through the pressure regulator to maintain downstream fluid pressure at a desired level. Typically, a pressure regulator is used to reduce the pressure of a fluid from a higher pressure down to a lower pressure. For example, some welding systems use pressurized gas either for fuel or to form a gas shield around a weld surface. The gas is stored at a high pressure so that the pressure of the gas within a cylinder is sufficient to cause the gas to flow throughout the system and so that as much gas as possible can be stored within the limited volume of the cylinder. However, welding systems do not operate well at the high pressures associated with the pressurized gas within the cylinder. Therefore, a pressure regulator is typically used to reduce the pressure of the gas down to a lower, more conducive, gas pressure. 
     Typically, a pressure regulator has an inlet, an outlet and a valve to control the flow of fluid from the inlet to the outlet. The regulator senses the pressure downstream and opens the valve to allow additional fluid to flow through the regulator to raise the pressure downstream. The pressure regulator closes the valve once the desired downstream pressure has been achieved. A typical valve for a pressure regulator has a valve stem and a seat surrounding an orifice. When downstream pressure is lower than desired, the valve directs the stem away from the seat to allow fluid to flow through the orifice to raise the pressure of the fluid downstream. When the desired downstream pressure is achieved, the valve urges the stem against the seat to prevent more fluid from flowing through the orifice. 
     In a typical pressure regulator, several forces act on the stem. A biasing spring is typically used to maintain the stem against the seat when no other forces are acting on the stem, or when the sum of the other forces acting on the stem is zero. A helical regulating spring is typically used to establish the desired downstream pressure. For low pressure applications, a diaphragm is typically used to couple the force of the regulating spring to the stem. A diaphragm is flexible and couples the pressure of the fluid downstream of the regulator to the regulating spring. For higher pressure applications, a movable piston is typically used to couple the force of the regulating spring to the stem. When the force produced by the pressure of the fluid acting on the diaphragm or piston is greater than the force applied by the regulating spring, the diaphragm or piston is positioned so that the stem is seated against the seat. When the force produced by the pressure of the fluid acting on the diaphragm is less than the force applied by the regulating spring, the diaphragm is positioned so that the stem is unseated from the seat, allowing fluid to flow downstream to raise the downstream fluid pressure. Eventually, the rise in pressure downstream will be sufficient to overcome the force of the regulating spring and close the regulator, thereby establishing the downstream pressure. By varying the force applied to the diaphragm or piston by the regulating spring, the downstream pressure can be adjusted. A threaded mechanism is typically used to vary the force applied by the spring by compressing or uncompressing the regulating spring. 
     Typically, the regulator is configured with a body and a bonnet to house the regulator components. The helical adjusting spring establishes the size of the bonnet because the bonnet must be large enough to receive the helical adjusting spring. Consequently, the bonnet may be very large compared to the body. Furthermore, the body and other internal components must be configured to cooperate with the helical adjusting spring. The larger the adjusting spring, the larger the other components must be to properly cooperate with the adjusting spring. 
     Further difficulties arise when the pressure regulator is used to regulate very high pressures. For example, a high pressure regulator may be used to reduce an upstream pressure of 10,000 pounds per square inch to a downstream pressure of 6,000 pounds per square inch. The force that must be generated by the adjusting spring to regulate these pressures is very large. This may require a very large helical spring to generate the necessary force to control the pressure. 
     There exists a need for a pressure regulator valve assembly that solves some or all of the problems outlined above. Specifically, there is a need for a pressure regulator that uses a force provided by a device other than a helical spring to regulate fluid pressure. 
     SUMMARY OF THE INVENTION 
     The present technique provides a novel regulator designed to respond to such needs. According to one aspect of the present technique, a pressure regulator comprising a movable stem and at least one disc spring is featured. The movable stem is operable to control fluid flow through the pressure regulator to regulate fluid pressure downstream of the pressure regulator. In a first position of the stem, the stem blocks fluid flow through the pressure regulator. In a second position of the stem, the stem enables fluid to flow through the pressure regulator. Downstream fluid pressure produces a first force to urge the stem towards the first position. The at least one disc spring produces a second force to urge the stem towards the second position. 
     According to another aspect of the present technique, a pressure regulator to control downstream fluid pressure is featured. The pressure regulator comprises a movable stem, a movable piston, and a disc spring. The movable stem operable to control fluid flow through the pressure regulator. The movable piston is coupled to the stem to direct movement of the stem. Downstream fluid pressure produces a first force acting on the piston and the disc spring produces a second force that acts on the piston. 
     According to yet another aspect of the technique, a fluid supply system is featured. The fluid supply system comprises a source of pressurized fuel and a pressure regulator. The pressure regulator is fluidicly coupled to the source of pressurized. The pressure regulator comprises a plurality of disc springs and a disc spring compression assembly. The disc spring compression assembly is operable to variably compress the plurality of disc springs. When the plurality of disc springs are compressed they produce a spring force to urge the pressure regulator to open to allow fluid to flow through the pressure regulator from the source of pressurized fluid to raise downstream fluid pressure. 
     According to yet another aspect of the technique, a method of assembling a pressure regulator is featured. The method comprises placing at least one disc spring within a cavity formed between a first and a second pressure regulator housing, wherein the at least one disc spring provides a spring force to urge the pressure regulator to enable fluid flow through the pressure regulator. The method further comprises securing the first pressure regulator housing to the second pressure regulator housing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and: 
     FIG. 1 is a perspective view of a pressure regulator, according to an exemplary embodiment of the present technique; 
     FIG. 2 is a cross-sectional view of the pressure regulator of FIG. 1, taken generally along line  2 — 2  of FIG. 1; 
     FIG. 3 is a top view of a disc spring, according to an exemplary embodiment of the present invention; 
     FIG. 4 is a cross-sectional view of the disc spring of FIG. 4, taken generally along line  4 — 4  of FIG. 3; 
     FIG. 5 is an exploded view of the components of the central housing of FIG. 1; 
     FIG. 6 is a cross-sectional view of a valve assembly illustrating a stem positioned in an unseated position, according to an exemplary embodiment of the present technique; 
     FIG. 7 is a cross-sectional view of a valve assembly illustrating the stem positioned in a seated position, according to an exemplary embodiment of the present technique; 
     FIG. 8 is an alternative arrangement of disc springs in a pressure regulator, according to an exemplary embodiment of the present technique; and 
     FIG. 9 is an alternative embodiment of a pressure regulator that utilizes a diaphragm, according to an exemplary embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring generally to FIG. 1, an exemplary pressure regulator  10  is illustrated. The pressure regulator  10  has a central housing  12  that houses the internal components of the pressure regulator  10 . The central housing  12  has a fluid inlet  14  and a fluid outlet  16 . Fluid enters the regulator  10  through the inlet  14  and exits through the outlet  16 . An adjusting screw  18  is used to operate the pressure regulating portions of the pressure regulator  10  to establish the downstream pressure. An upstream pressure gauge  20  is used to indicate the pressure of the fluid entering the pressure regulator  10 . A downstream pressure gauge  22  is used to indicate the pressure of fluid downstream of the pressure regulator  10 . The pressure regulator  10  also may have a relief valve (not shown). The relief valve is set to relieve pressure if the pressure within the pressure regulator exceeds a pre-set amount. This protects the regulator from damage due to over-pressurization. 
     Referring generally to FIGS. 2 and 3, the illustrated central housing  12  has a body  24  and a bonnet  26 . The bonnet  26  is threaded onto the body  24  to form a protective shell for the internal components of the pressure regulator  10 . The body  24  is formed to create an internal fluid flow path  28  through the pressure regulator  10 . The body  24  also has threaded openings to enable the pressure gauges to be secured to the pressure regulator and to be in fluid communication with the upstream and downstream fluid pressures. A valve assembly  30  is disposed in the internal fluid flow path  28  to control fluid flow from the inlet  14  to the outlet  16 . 
     The valve assembly  30  has a seat  32  and a stem  34 . The seat  32  is maintained in position by a hollow seat retainer  36  (see, e.g., FIGS.  6  and  7 ). In the open position of the valve assembly  30 , the stem  34  is positioned relative to the seat  32  such that fluid is able to flow through the seat  32  and the seat retainer  36 . In the closed position of the valve assembly  30 , the stem  34  is positioned against the seat  32  to block fluid flow through the seat  32  and seat retainer  36 . In the illustrated embodiment, the stem  34  is coupled to a movable piston  38 . As discussed more fully below, the movable piston  38  is positioned in response to downstream fluid pressure and a spring force provided by one or more disc springs  40 . In the illustrated embodiment, four disc springs are used to provide the spring force. Additionally, a biasing spring  42  is used to bias the stem  34  to the seated position against the seat retainer  36 . An inner friction sleeve  44  and an outer friction sleeve  46  are used to dampen movement of the stem  34 . 
     The piston  38  is housed within a piston housing  48 . The piston housing  48  is stationary and the piston  38  is free to move within the piston housing  48 . A sealing member  50 , such as an O-ring, is used to form a seal between the piston housing  48  and the body  24 . Another sealing member  52 , such as an O-ring, is used to form a seal between the piston  38  and the interior of the piston housing  48 . The piston housing  48  has a hole  54  that is used to guide a cylindrical portion  56  of the piston  38  during movement of the piston  38 . 
     A lower spring button  58  and an upper spring button  60  are used to direct the movement of the disc springs  40  during compression and expansion. As best illustrated in FIGS. 4 and 5, each disc spring  40  has a central opening  62  therethrough. In the illustrated embodiment, each disc spring has a relatively flat portion  64  radially surrounding the central opening  62 . Surrounding the flat portion  64  is an angled portion  66 . Each disc spring  40  is compressed by flattening the angled portion  66 . The disc springs  40  are elastically deformed during compression, generating a spring force to oppose the force of compression. The disc spring  40  returns to its original shape after the force of compression is removed. Referring again to FIGS. 2 and 3, in the illustrated embodiment, the lower spring button  58  has a cylindrical portion  68 . The disc springs  40  and lower spring button  58  are assembled so that the cylindrical portion is disposed through the central opening  62  of at least one disc spring  40  to guide the movement of the disc spring  40 . 
     The second spring button  60  is used with the adjusting screw to produce a spring force that is coupled to the piston  38 . In the illustrated embodiment, the adjusting screw  18  is threaded through a threaded opening  70  in the bonnet  26 . The second spring button  60  has a receiving portion  72  that is adapted to receive the adjusting screw  18 . As the adjusting screw  18  is threaded into engagement with the upper spring button  60 , the upper spring button  60  is driven against the disc springs  40 . This force is translated through the disc springs  40  the lower spring button  58  and the piston  38 . The pressure of fluid downstream of the valve assembly  30  also produces a force that urges the piston  38  against the lower disc spring  58 . Thus, the disc springs  40  are compressed between the lower and upper spring buttons. 
     In the illustrated embodiment, the adjusting screw  18  is positioned by rotating a handle  74  coupled to the adjusting screw  18 . To raise the downstream pressure to a higher desired pressure, the adjusting screw  18  is threaded into the bonnet  26 , which forces the disc springs  40  against the lower spring button  58  and piston  38 . This action compresses the disc springs  40  and increases the force that must be provided by the fluid pressure downstream to overcome the force of the disc springs  40  to close the seat  32  against the seat retainer  36 . To lower the downstream pressure, the adjusting screw  18  is threaded out of the bonnet  26 , which reduces the force of the disc springs  40  against the lower spring button  58  and piston  38 . 
     When downstream pressure is lower than the desired pressure set by the disc springs  40 , the piston  38  will driven downward, in the view of FIG.  2 . The downward movement of the piston  38  is coupled to the seat  32  by the stem  34 . The downward movement of the stem  34  compresses the disc springs  40  and positions the stem  34  to allow fluid to flow downstream, thereby raising the pressure downstream. Eventually, the downstream pressure should rise to the new desired pressure and the piston  38  will overcome the force of the disc springs  40  and be driven upward, in the view of FIG.  2 . The upward movement urges the stem  34  against the seat  32 , stopping additional fluid flow through the pressure regulator  10 . A similar process takes place if the adjusting screw  18  is rotated outward from the bonnet  26 . The force applied by the disc springs  40  is thereby lowered. As the pressure downstream drops, the stem  34  will open to raise the pressure. However, the downstream pressure needed to overcome the spring  40  and position the stem  34  in the closed position is lessened, thereby maintaining downstream pressure at a lower pressure. 
     Referring generally to FIGS. 6 and 7, the seat retainer  36  has an orifice  76  to enable fluid to flow through the seat retainer  36  and fluid path  28  from the inlet  14  to the outlet  16 . When the valve assembly  30  is in the open position, as illustrated in FIG. 6, the stem  34  is positioned downward, in this view, such that fluid  78  is able to flow through the internal passageways  28  and orifice  76  from the inlet  14  to the outlet  16  of the pressure regulator  10 . When the valve assembly is in the closed position, as illustrated in FIG. 7, the stem  34  is positioned upward, in this view, such that a conical portion  80  of the stem  34  is positioned against the seat  32 , blocking fluid flow through the orifice  76 . 
     The stem  34  follows the movement of the piston  38 . The stem  34  extends through the orifice  76  into a recess  82  in the piston  38 . The stem  34  and recess  82  are configured so that the stem  34  is secured to the piston  38  when the stem  34  is driven into the recess  82 . When the force of the disc springs  40  is greater than the force produced by the pressure of the downstream fluid, the lower spring button  58  drives the piston  38 , and stem  34 , downward, as represented by arrows  84  in FIG. 6, enabling fluid flow through the pressure regulator  10 . When the force of the pressure of the downstream fluid is greater than the force produced by the disc springs  40 , the piston  38  drives the lower spring button  58 , and stem  34 , upward, as represented by arrows  86  in FIG. 7, preventing fluid flow through the pressure regulator  10 . 
     Referring generally to FIG. 8, the disc springs  40  also may be positioned back-to-back or, in other words, face-to-face. This arrangement provides a more precise control of the disc spring force than does the end-to-end arrangement illustrated in FIGS. 1-7. 
     Referring generally to FIG. 9, as an alternative to using a piston and piston housing, a flexible diaphragm  88  may be used. The diaphragm  88  forms a seal across the interior of the central housing  12 . The force provided by the downstream pressure tries to flex the diaphragm  88  upward, in this view, while the force of the disc springs  40  tries to flex the diaphragm  88  downward, in this view. The disc springs  40  are coupled to the diaphragm  88  by a backup plate  90 . A diaphragm washer  92  is used to protect the diaphragm  88  from damage when installing the bonnet  26  to the body  24 . A stem support  94  is used to enable the stem  34  to follow the movement of the diaphragm  88 . A spring button  96  is used to enable the adjusting screw  18  to control the force provided by the disc springs  40  onto the diaphragm  88 . 
     When the force of the disc springs  40  is greater than the force produced by the pressure of the downstream fluid, the diaphragm  88  is flexed downward. The diaphragm  88  drives the stem support piston  38  and stem  34  downward, in this view, enabling fluid flow through the pressure regulator  10 . When the force of the pressure of the downstream fluid on the diaphragm is greater than the force produced by the disc springs  40 , the diaphragm  88  is flexed upward. The biasing spring  42  drives the stem  34  and stem support  94  upward, blocking the orifice (not shown) and preventing fluid flow through the pressure regulator  10 . 
     It will be understood that the foregoing description is of preferred exemplary embodiments of this invention, and that the invention is not limited to the specific forms shown. For example, the regulator may be a dual-regulator system. Additionally, the regulator may be used with gas welding systems, compressed air systems, or any other suitable system utilizing a pressure regulator. Furthermore, the regulator may be configured to control pressure over a variety of pressure ranges. These and other modifications may be made in the design and arrangement of the elements without departing from the scope of the invention as expressed in the appended claims.