Differential pressure regulator

Abstract

The regulating valve includes a valve body defining a central bore having a longitudinal axis. A rod is coupled to the diaphragm and slides within the central bore along the longitudinal axis. The rod has a planar end. A spring, such as a coil spring, is mounted in the central bore and engages the lever. One or more parallel passages are formed in the valve body extending parallel to the bore. One or more slits are formed in the valve body, each of the one or more slits connecting one of the one or more parallel passages to the central bore. The regulating valve may be used as a pressure regulator in a pumping system.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application was filed as a PCT international patent application on December 27, 2023, and claims priority to and the benefit of U.S. Provisional Application No. 63 / 477,343, filed on December 27, 2022, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates to a pressure regulator, and more particularly to a pressure regulating valve for maintaining an appropriate amount of hydraulic fluid in a fluid system. Background Art

[0004] Conventional pressure regulators for fluid systems, such as hydraulic fluid systems, are designed to establish a control pressure close to a pressure set point with as little change as possible. This is typically achieved with a poppet-type valve, which requires relatively little movement to reach a high flow position from a fully closed position. Such poppet valves can be sized for a wide range of applications. If a complete shutoff of the fluid is required, such poppet-type valves are generally preferred. However, when the flow being regulated is small, vibrations may occur due to the valve closing and opening rapidly with very small movements. For some applications, such as regulating the supply of hydraulic oil to a hydraulically driven diaphragm pump, small pressure variations are acceptable and complete shutoff is not required, so a more stable valve opening method can be utilized.

[0005] Pressure regulating valves are also used for higher flow rates, such as pumping slurries. In this application, the fluid feeding a large diaphragm pump has a high solids content. This type of fluid tends to precipitate solids in stagnant areas, forming solid clumps. When this clump opposes the movement of components in the pump, it is often referred to as packing out. Traditional poppet-type valves can become packed out. To prevent this from happening in valves or pressure gauges, an isolation fluid is sometimes used. This is an area in the connection between the inlet slurry and the valve that is filled with a fluid, such as oil. A diaphragm or piston is used to separate the oil from the slurry. This is a complex arrangement that requires a lot of effort to fill and maintain. Therefore, it is beneficial if the valve does not need to be isolated from the slurry.

[0006] It is therefore understandable that an improved pressure regulating valve is needed to maintain hydraulic fluid pressure. Such a regulator should create a flow channel of variable size depending on the position of a sliding rod. Such a regulator should achieve a range of operating pressures that results in a highly stable valve with minimal vibration, in which the position of the spool can be balanced across a range of positions. Such a valve should function even with fluids having a high solids content. Therefore, such a valve should avoid clogging and related problems. The present invention addresses these and other problems associated with fluid pressure regulators. Summary of the Invention

[0007] The present invention relates to a pressure bypass regulating valve. The regulating valve can be used in a pumping system such as a slurry pumping system. The regulating valve has a valve body that defines a central hole having a longitudinal axis. The diaphragm is connected to a rod that slides along the longitudinal axis within the central hole. The rod is cylindrical with flat ends. A coil spring is installed in the central hole and engages the rod. The size of the spring is designed to have a spring constant corresponding to the desired full flow range and to have an allowable pressure. In one embodiment, parallel channels extending parallel to the hole are formed in the valve body. Each channel has an associated bridging slit that connects the corresponding parallel channel to the central hole. The valve body forms a shoulder in the central hole that is engaged by the coil at the end of the spring.

[0008] In one embodiment, the slits are tapered. The tapered slits change the flow rate as the cylindrical rod moves longitudinally, exposing slits of varying cross-sections to the central aperture and increasing the rate of change of the fluid flow. In another embodiment, the multiple slits have different lengths. As the cylindrical rod moves longitudinally along the central aperture, more slits are exposed, and the flow rate through the slits and passages increases as the cross-sectional area increases. As the cylindrical rod moves along the central aperture to cover the tapered slits or slits of varying lengths, the flow rate slows at an increasing rate.

[0009] A pressure regulating valve functions as a bypass valve in pressure-regulated systems. An example application is a pumping system for slurries. Such a system may include a hydraulically driven diaphragm pump. In such a system, the bypass valve maintains pressure in the hydraulic oil line from the pump by discharging excess flow to a discharge port. The diaphragm pump is supplied with pressure from the supply pump via the supply line.

[0010] These features of novelty and various other advantages which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages and the objects attained by its use, reference should be made to the accompanying drawings and the accompanying descriptive matter which form another part hereof, in which there is shown and described a preferred embodiment of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Referring now to the drawings, wherein like reference numerals and letters designate corresponding structure throughout the several views:

[0012] Figure 1 is a side cross-sectional view of the adjuster according to the present invention at a mid-stroke position;

[0013] Figure 2 It is along Figure 1 A cross-sectional view of the valve body of the regulating valve taken along line 2-2;

[0014] Figure 3 yes Figure 1 A schematic diagram of a typical application of the regulator is shown;

[0015] Figure 4 yes Figure 1 A side cross-sectional view of the regulating valve shown in the closed position;

[0016] Figure 5 yes Figure 1 A side cross-sectional view of the regulating valve is shown in a fully open position;

[0017] Figure 6 is a perspective view of an embodiment of a regulating valve according to the principles of the present invention, which includes two tapered slits in a valve body;

[0018] Figure 7 yes Figure 6 An end view of the regulating valve is shown;

[0019] Figure 8 It is along Figure 7 A cross-sectional view of the valve body of the regulating valve taken along line 8-8;

[0020] Figure 9 is a perspective view of an embodiment of a regulating valve according to the principles of the present invention, which includes four slits having different lengths;

[0021] Figure 10 yes Figure 9 An end view of the regulating valve is shown;

[0022] Figure 11 It is along Figure 10 A cross-sectional view of the valve body of the regulating valve taken along line 11-11; and

[0023] Figure 12 In typical applications Figure 1 A graph of flow rate versus stem position for a regulating valve is shown. DETAILED DESCRIPTION

[0024] refer to Figure 1 、 Figure 2 、 Figure 4 and Figure 5, the regulator 20 has a valve body 22 that includes an inlet port 24 and a discharge or outlet port 26. In the embodiment shown, a third auxiliary port 28 is provided that is in the same bore as the inlet port 24. If desired, it can be used as an outlet port to eliminate the need for a T-fitting in the inlet line in some applications. Alternatively, the auxiliary port 28 can be used for a pressure gauge or other device for monitoring the controlled fluid. The valve body 22 has a central bore 30 connected to the outlet port 26. One or more channels 32 are parallel to the central bore 30 and are fluidly connected to the central bore 30 by slits 34. As Figure 2 As shown, each slit 34 is narrower than the associated channel and forms a connecting neck or channel between the central bore 30 and the associated parallel channel 32. A cylindrical rod 36 is positioned in the central bore 30 and is axially slidable along the central bore 30. The cylindrical rod 36 has a flat end that is transverse to the longitudinal axis of the central bore 30. The rod 36 is attached to the diaphragm 38 by a lower clamp 40 and an upper clamp 42 and a screw fastener 44. The valve body 22 forms a diaphragm support surface 52. As shown Figure 5 As shown, the diaphragm support surface 52 provides continuous support without sharp edges or corners that could tear the diaphragm 38. The diaphragm support surface 52 also prevents the diaphragm 38 from being stretched too far. The diaphragm 38 is clamped in place by the upper housing 46. The upper housing 46 includes the control pressure port 48.

[0025] A spring 50, such as a coil spring, is held in place by the upper housing 46 and in contact with the upper clamp 42 of the diaphragm assembly. A shoulder 54 is formed in the central bore 30. The shoulder 54 is configured to receive the end of the coil spring 50 so that the coils of the spring 50 are adjacent to the wall of the central bore 30. Thus, as described below, solids that may tend to cause a blockage are not trapped between the spring 50 and the wall of the central bore 30.

[0026] The slits 34 can be sized to allow for adjustment of the maximum flow rate supplied. The slits can be tapered to allow for increasingly higher flow rates, as more slits are opened as the rod 36 is moved. Alternatively, when multiple slits are used, each slit can have a different length so that at low discharge flow rates, only one slit is exposed, and as the rod 36 is retracted, more and more slits are exposed.

[0027] refer to Figure 3, shows a pumping system 200 according to the present invention, utilizing three pumps and a control system with a diaphragm pump 100. The hydraulically driven diaphragm pump 100 is shown with a single cylinder, but the present invention is also applicable to multi-cylinder pump assemblies in which all cylinders are supplied through a common connection to the oil pressure line. A regulator 20 controls the oil pressure and the supply of hydraulic fluid to the diaphragm pump 100. The regulator 20 maintains pressure in the hydraulic oil line 126 from the oil pump 124 by discharging excess flow to a discharge port 26. The diaphragm pump 100 is pressure-fed by a supply pump 122 through a supply line 142. The hydraulic oil pump 124 draws hydraulic fluid from an oil reservoir / sump 146 and supplies it to the inlet port 24 of the regulator 20. The auxiliary port 28 of the regulator 20 is connected to the hydraulic oil inlet of the diaphragm pump 100 via a line 126. A return line 120 is connected to the outlet port 26 of the regulator 20 for returning fluid to the reservoir 146. Pressure port 48 of regulator 20 is connected to diaphragm pump supply line 142. The inlet of diaphragm pump 100 is connected to feed pump 122 via line 142, which provides boost pressure for diaphragm pump 100. Oil pump 124 supplies hydraulic fluid to diaphragm pump 100. The fluid being pumped is the fluid being pumped by both feed pump 122 and diaphragm pump 100. Oil pump 124 is a separate fluid system and supplies hydraulic fluid to diaphragm pump 100.

[0028] In pumping system 200, diaphragm pump 100 has a diaphragm 102 driven by hydraulic fluid / oil in a transfer chamber 104. The hydraulic fluid is displaced by a plunger or piston 106 driven by a crankshaft 108. This displacement of piston 106 is transmitted by the hydraulic fluid, causing displacement of diaphragm 102. A certain amount of oil is contained in an oil reservoir 146, which serves as a fluid reservoir. This oil reservoir is typically the crankcase of pump 100, but may be a separate oil supply from the oil supply used to lubricate the crankshaft bearings and other moving parts of diaphragm pump 100. Oil reservoir 146 is typically at atmospheric pressure. Diaphragm pump 100 has a valve spool 112 and two check valves 114 and 116 that control the flow of hydraulic oil. When transfer chamber 104 is underfilled, first check valve 114 (often called an underfill valve) supplies oil to the chamber. Second check valve 116 acts as an overfill valve, allowing oil to exit transfer chamber 104 when overfilled. During normal operation, there may be leakage past the piston 106, which causes the transfer chamber 104 to be underfilled. The underfill condition causes the diaphragm 102 to move further back on the suction stroke and moves the spool 112 to expose the port of the underfill line 118, thereby allowing oil to be drawn from the sump 146. This occurs during the suction stroke of the diaphragm pump 100, with the underfill valve 114 preventing oil from leaving the transfer chamber 104 during the pressure stroke. The overfill valve 116, when not covered by the spool valve 112, allows excess oil to drain from the transfer chamber 104 to the sump 146 through the return line 120.

[0029] The pressure and flow rate capacity range can be established in several ways. The overall size of the regulating valve 20 can be configured to accommodate the maximum flow rate. In addition, for a given valve size, the number of channels 32 and slits 34 can be increased to accommodate more bypasses. Figures 6 to 11 In an alternative embodiment of the regulator, the valve body may have a variable flow passage. Figures 6 to 8 As shown, slit 32A is tapered. The tapered configuration achieves high bypass flow when fully open. However, tapered slit 32A also has a reduced opening near the closed position to accommodate reduced flow. The opposite ends of slit 32A have different areas and tapered sides, which provide a gradually changing cross-sectional area for fluid flow between the fully open and fully closed positions and avoid drastic flow rate changes. As rod 36 extends and retracts, the cross-sectional area of ​​central bore 30, slit 32A, and passageway 34 gradually increases and decreases to accommodate increasing and decreasing fluid flow.

[0030] refer to Figures 9 to 11 Variable flow rate response can also be achieved using multiple slits 32B-32E of varying lengths. In this configuration, the regulating valve body 22B has four parallel passages 34 and four slits 32B, 32C, 32D, and 32E, each connecting the central bore and a corresponding parallel passage 34. Because each of the slits 32B, 32C, 32D, and 32E has a different length, the slits open and close at different times to the flow as the stem 36 moves axially along the central bore 30. As the stem retracts, only a single slit is exposed, and as the valve opens further and the stem 36 moves, more and more slits are additionally exposed until all four slits 32B, 32C, 32D, and 32E are exposed. It should be understood that while four slits 32B, 32C, 32D, and 32E and corresponding parallel passages 34 are shown, it will be appreciated that fewer or more slits and corresponding parallel passages may be utilized to suit a particular application.

[0031] refer to Figure 12 , shows the responses associated with various embodiments of valve bodies 22, 22A, and 22B. It should be understood that for Figure 1 、 Figure 2 、 Figure 4 and Figure 5For the straight rectangular slits shown, the flow area increases at an ever-increasing rate. It should be understood that for a similarly sized valve body 22A, the cross-sectional flow area increases, but at an increasing rate due to the tapered slit configuration. For a similarly sized valve body 22B, the cross-sectional flow area increases at a different rate as each of the slits 32B, 32C, 32D, and 32E are exposed. Thus, there is a first rate of increase equal to that of the valve with straight slits 32. However, as additional slits 32C, 32D, and 32E are exposed, the exposure rate changes at a greater rate, represented by the steeper curve.

[0032] Example

[0033] The regulator 20 is particularly suitable for use as a bypass regulator, for example Figure 3 As shown. In operation, the oil pump 124 provides a fixed fluid flow rate. In conventional pumping applications, this flow rate is about 3 gallons per minute (gpm). The diaphragm pump 100 receiving oil may need to be filled with a full 3 gpm when first primed. In this configuration, the regulating valve 20 is "fully closed" and all of the slits 34 are covered so that no oil bypasses back to the reservoir / sump 146. In this case, the regulating valve 20 is preferably sized so that the pressure regulation flow is determined by the restrictions in the diaphragm pump oil control system 200. The regulator 20 will remain closed unless the pressure exceeds a predetermined level, such as 10 psi, and then the regulator 20 will begin to expose the slits 34 to limit the increase in pressure.

[0034] The "cracking pressure" corresponds to the position at which rod 36 is about to expose the slit. In the example system 200, the cracking pressure may be 10 psi. When diaphragm pump 100 is operating at low pressure or not in operation, there is little or no demand for oil. In this configuration, valve 20 is "fully open," causing all 3 gpm from oil pump 124 to be bypassed to reservoir 146. When this state is reached, maximum slit opening is achieved. The spring is fully compressed, and the spring rate is such that the controlled pressure is now approximately 15 psi.

[0035] During operation, diaphragm pump 100 will typically have a supply pressure of approximately 50 psi from line 142. To properly control diaphragm pump 100, hydraulic oil line 126 needs to be approximately 10 psi higher than the supply pressure, or 60 psi in this case. The 50 psi from line 142 is directed through port 28 to the top side of regulator diaphragm 38. Spring 50 also applies an additional force equal to 10 psi to the top of diaphragm 38. When hydraulic pump 124 is activated, pressure will build in line 126 and in the regulator's main channel, which connects to channel 32 and also to the bottom side of diaphragm 38. Once the pressure reaches 60 psi, the diaphragm will move upward, causing rod 36 to open slit 34, releasing fluid into reservoir 146 at atmospheric pressure. The increase in pressure will displace more fluid until an equilibrium near 60 psi is reached. If the demand for hydraulic fluid increases, the pressure will drop, and the valve will close until the controlled fluid reaches 60 psi again.

[0036] Under normal full pressure operation, a typical oil demand for the diaphragm pump 100 may be about 1.5 gpm. Under these conditions, the remaining 1.5 gpm is bypassed through port 3 back to the oil reservoir 146. The valve moves the stem 36 so that about 10 psi is maintained in the controlled flow in the line 126. Ideally, this will be about mid-stroke of the stem and diaphragm assembly.

[0037] To establish the pressure range within which valve 20 operates, spring 50 must be matched to diaphragm 38 to produce the desired pressure at a given valve opening. Using an exemplary system with a desired pressure range of 5 to 15 psi, the following can be used. A diaphragm is selected that can cover the travel of rod 36. A typical travel is approximately 0.75 inches. A typical diaphragm 38 with this travel will have an equivalent area of ​​approximately 4.9 square inches (i.e., the area of ​​a 2.5-inch diameter piston). Spring 50 has a constant that matches the compression of spring 50 through the full flow range at the permitted pressure. From a break pressure of 5 psi to a fully open pressure of 15 psi, rod 36 will move approximately 0.625 inches. This 4.9 square inches of equivalent area translates to a required spring force, F = P*A, of 24.5 pounds when open and 73.5 pounds when fully open. The change in force divided by the change in spring length is 49 pounds divided by 0.625, yielding a spring constant of 78.4 pounds per inch.

[0038] A traditional application for the regulating valve 20 is pumping slurries. The slurry supplied to a large diaphragm pump 100 has a high solids content. This high-solids fluid is directed to port 48 of the regulating valve 20. This type of fluid tends to precipitate solids in stagnant areas and form solid clumps. When such clumps resist the movement of components in the pump, it is often referred to as a blockage. To prevent this from occurring in valves or pressure gauges, a barrier fluid is sometimes used. This is an area filled with a fluid, such as oil, in the connection between the inlet slurry and the valve 20. A diaphragm or piston is used to separate the oil from the slurry. This is a complex arrangement that requires significant effort to fill and maintain. Therefore, it is beneficial if the valve does not need to be isolated from the slurry. In the regulating valve 20 of the present invention, the connection port at the end of the spring 50 is much larger than that required to simply transmit a pressure signal. When the regulating valve 20 is used with a slurry connected to the sensing port 48, the regulating valve 20 can be oriented with the sensing port 48 facing downward. This configuration allows solids to settle outside the valve housing and, further, tends to flush the solids out of the spring area when the valve 20 is cycled fully open.

[0039] It should be understood, however, that while many of the features and advantages of the invention and details of its structure and function have been set forth in the foregoing description, this disclosure is illustrative only and changes may be made in details, especially in shape, size and arrangement of parts, within the full scope indicated by the broad general meaning of the terms expressed in the appended claims within the principles of the invention.

Claims

1. A regulating valve, comprising: a valve body defining a central bore having a longitudinal axis; diaphragm; a rod coupled to the diaphragm and slidable within the central bore along the longitudinal axis, the rod having a planar end; a spring mounted in the central bore and engaging the rod; one or more parallel passages formed in the valve body and extending parallel to the central bore; as well as One or more slits, each of the one or more slits connecting one of the one or more parallel channels to the central bore. 2 . The regulating valve of claim 1 , wherein the valve body includes a shoulder engaged by an end of the spring. 3 . The regulating valve of claim 1 , wherein the spring comprises a coil spring, and the valve body comprises a shoulder engaged by an end of the coil spring. The regulating valve of claim 1 , wherein one or more of the slits are tapered. The regulating valve of claim 1 , wherein the one or more slits comprise a plurality of slits of different lengths. The regulating valve according to claim 1 , wherein a cross-sectional area of ​​each of the slits is smaller than a cross-sectional area of ​​connected parallel channels. 7 . The regulating valve according to claim 1 , wherein a width of each of the slits is smaller than a width of connected parallel channels.

8. The regulating valve of claim 1, wherein the valve body includes a support surface for engaging the diaphragm.

9. The regulating valve of claim 1, wherein the diaphragm is clamped in place by an upper housing.

10. The regulating valve of claim 1, wherein the spring constant of the spring matches the compression of the spring by the cylindrical stem over a full flow range at below an allowable pressure.

11. A regulating valve, comprising: a valve body defining a central bore having a longitudinal axis; diaphragm; a rod coupled to the diaphragm and slidable within the central bore along the longitudinal axis, the rod having a planar end; a spring mounted in the central bore and engaging the rod; a plurality of parallel passages formed in the valve body and extending parallel to the central bore; as well as A plurality of slots, each of the plurality of slots connecting one of the plurality of parallel channels to the central bore.

12. The regulating valve of claim 1, wherein one or more of the plurality of slits are tapered.

13. The regulating valve of claim 1, wherein the plurality of slits comprises slits having a plurality of different lengths.

14. A diaphragm pump system comprising: a diaphragm pump having a transfer chamber containing a hydraulic fluid; a first valve that allows hydraulic fluid to enter the transfer chamber; a second valve that allows removal of hydraulic fluid from the transfer chamber; a hydraulic fluid reservoir in fluid communication with the transfer chamber; wherein the hydraulic fluid pressure is higher than the pumped fluid inlet supply pressure; a pressure bypass regulating valve that bypasses fluid flow to the transfer chamber, the regulating valve comprising: a valve body defining a central bore having a longitudinal axis; diaphragm; a rod coupled to the diaphragm and slidable within the central bore along the longitudinal axis, the rod having a planar end; a spring mounted in the central bore and engaging the rod; a plurality of parallel passages formed in the valve body extending parallel to the central bore; and A plurality of slots, each of the plurality of slots connecting one of the plurality of parallel channels to the central bore.

15. The diaphragm pump system of claim 14, wherein the valve body includes a shoulder engaged by an end of the spring.

16. The diaphragm pump system of claim 14, wherein the spring comprises a coil spring and the valve body comprises a shoulder engaged by an end of the coil spring.

17. The diaphragm pump system of claim 14, wherein one or more of the slits are tapered.

18. The diaphragm pump system of claim 14, wherein the one or more slits comprise a plurality of slits of different lengths.

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