Overpump flow measurement device and method for diaphragm compressors

Abstract

A diaphragm compressor system, comprising: a diaphragm compressor; a downstream check valve; a pressure transducer; a flow measurement device configured to measure overpump oil flow of the diaphragm compressor by monitoring pressure within the flow measurement device, the flow measurement device comprising; an accumulator chamber comprising: a cylinder; at least one oil relief passage disposed within the cylinder; a spring-loaded piston movable within the cylinder; a spring biasing the piston; and an orifice within the piston; an inlet to the accumulator chamber configured to allow overpump oil into the accumulator chamber; and an outlet to the accumulator chamber; wherein the accumulator chamber is configured to accumulate oil during the time when oil flows and allows oil to flow during the idle time through the orifice. When the piston is displaced oil flows through the at least one oil relief passage disposed within the cylinder. The spring-loaded piston is displaced within the cylinder to a position which is proportional to the oil flow.

Description

Attorney Docket No. P25349WOOOOVERPUMP FLOW MEASUREMENT DEVICE AND METHOD FOR DIAPHRAGM COMPRESSORSRELATED APPLICATION DATA

[0001] This application claims priority to U.S. Provisional Application No. 63 / 728,138 filed December 4, 2024 the disclosure of which is hereby incorporated by reference in its entirety.BACKGROUND OF THE DISCLOSURE

[0002] The present invention is directed to diaphragm compressors.

[0003] A diaphragm compressor comprises a diaphragm that is actuated to pressurize a process gas for various purposes.SUMMARY

[0004] A feature and benefit of embodiments is a diaphragm compressor system, comprising: a diaphragm compressor comprising at least one compressor head, a crank case, and an overpump condition selected from one of a low overpump condition, a normal overpump condition, and a high relief or saturation overpump condition and a malfunction condition. The diaphragm compressor system may include an oil relief valve coupled to the at least one compressor head. The diaphragm compressor system may also include a flow measurement device configured to measure overpump oil flow of the at least one compressor head by monitoring pressure within the flow measurement device, the flow measurement device comprising: an inlet configured to receive oil from the oil relief valve; an outlet in fluid communication with the inlet and the crank case; an accumulator chamber configured to accumulate oil from the inlet. The accumulator chamber may comprise a cylinder comprising an inlet end and an outlet end; a spring-loaded piston movable within the cylinder, the spring- loaded piston comprising a piston head comprising a piston head area; a spring configured to bias the piston towards the inlet end of the cylinder, the spring comprising a spring constant; a variable volume cavity defined by the inlet end of the cylinder and the piston head; an orifice comprising an orifice diameter, the orifice fluidly coupling the inlet and the outlet, wherein the orifice diameter is configured to allow oil to flow through the orifice; and at least one oil relief passage disposed within the outlet end of the cylinder, the oil relieve passage comprising aAttorney Docket No. P25349WOOO proximal end. Tn certain embodiments, the spring-loaded piston is configured to be displaced towards the outlet end of the cylinder and beyond the proximal end of the at least one oil relief passage during the relief or saturation high overpump condition, and allow at least a portion of the oil to exit the accumulator chamber by bypassing the piston. The diaphragm compressor system may also include a pressure transducer in fluid communication with the accumulator chamber configured to measure the pressure of oil in the accumulator chamber. In certain embodiments, the piston head area and the spring constant are configured to allow the spring- loaded piston to be displaced within the cylinder to a position which is proportional to the oil flow during the normal overpump condition.

[0005] In certain embodiments, the cylinder comprises a cylindrical wall, and the at least one oil relief passage is disposed within the cylindrical wall.

[0006] In certain embodiments, the flow measurement device comprises a flow measurement device body comprising a central bore, wherein the cylinder is a cylinder insert disposed within the central bore of the flow measurement device body, wherein the cylinder insert comprises a cylindrical wall, and the at least one oil relief passage comprises radially spaced, elongated longitudinal apertures disposed in the cylindrical wall of the cylinder insert.

[0007] In certain embodiments, the orifice is disposed within the piston.

[0008] In certain embodiments, the orifice is disposed parallel to the piston.

[0009] In certain embodiments, a filter screen is disposed between the inlet and the piston.

[0010] In certain embodiments, the spring-loaded piston is configured to be disposed at the inlet end of the cylinder during the low or malfunction overpump conditions.

[0011] In certain embodiments, the spring-loaded piston is configured to be disposed between the inlet end and the outlet end of the cylinder during the normal overpump condition.

[0012] In certain embodiments, the spring constant is about 15 Ib / in, the piston head area is about 1.227 sq.in and the orifice diameter is about 0.016 inch.

[0013] In certain embodiments, at least one ball switch is configured to detect displacement of the spring-loaded piston. A feature and benefit of embodiments is a method of measuring overpump flow of a diaphragm compressor system, comprising providing a diaphragm compressor comprising at least one compressor head, a crank case, and an overpump condition selected from one of a low overpump condition, a normal overpumpAttorney Docket No. P25349WOOO condition, and a high relief or saturation overpump condition and a malfunction condition. The diaphragm compressor method may include coupling an oil relief valve coupled to the at least one compressor head. The diaphragm compressor method may also include measuring an overpump flow with a flow measurement device configured to measure overpump oil flow of the at least one compressor head by monitoring pressure within the flow measurement device, the flow measurement device comprising: an inlet configured to receive oil from the oil relief valve; an outlet in fluid communication with the inlet and the crank case; an accumulator chamber configured to accumulate oil from the inlet. The accumulator chamber may comprise a cylinder comprising an inlet end and an outlet end; a spring-loaded piston movable within the cylinder, the spring-loaded piston comprising a piston head comprising a piston head area; a spring configured to bias the piston towards the inlet end of the cylinder, the spring comprising a spring constant; a variable volume cavity defined by the inlet end of the cylinder and the piston head; an orifice comprising an orifice diameter, the orifice fluidly coupling the inlet and the outlet, wherein the orifice diameter is configured to allow oil to flow through the orifice; and at least one oil relief passage disposed within the outlet end of the cylinder, the oil relieve passage comprising a proximal end. In certain embodiments, the spring-loaded piston is configured to be displaced towards the outlet end of the cylinder and beyond the proximal end of the at least one oil relief passage during the relief or saturation high overpump condition, and allow at least a portion of the oil to exit the accumulator chamber by bypassing the piston. The diaphragm compressor system may also include a pressure transducer in fluid communication with the accumulator chamber configured to measure the pressure of oil in the accumulator chamber. In certain embodiments, the piston head area and the spring constant are configured to allow the spring-loaded piston to be displaced within the cylinder to a position which is proportional to the oil flow during the normal overpump condition.

[0014] In certain embodiments of the method of measuring overpump flow, the cylinder comprises a cylindrical wall, and the at least one oil relief passage is disposed within the cylindrical wall.

[0015] In certain embodiments of the method of measuring overpump flow, the flow measurement device comprises a flow measurement device body comprising a central bore, wherein the cylinder is a cylinder insert disposed within the central bore of the flow measurement device body, wherein the cylinder insert comprises a cylindrical wall, and the atAttorney Docket No. P25349WOOO least one oil relief passage comprises radially spaced, elongated longitudinal apertures disposed in the cylindrical wall of the cylinder insert.

[0016] In certain embodiments of the method of measuring overpump flow, the orifice is disposed within the piston.

[0017] In certain embodiments of the method of measuring overpump flow, the orifice is disposed parallel to the piston.

[0018] In certain embodiments of the method of measuring overpump flow, a filter screen is disposed between the inlet and the piston.

[0019] In certain embodiments of the method of measuring overpump flow, the spring- loaded piston is configured to be disposed at the inlet end of the cylinder during the low or malfunction overpump conditions.

[0020] In certain embodiments of the method of measuring overpump flow, the spring- loaded piston is configured to be disposed between the inlet end and the outlet end of the cylinder during the normal overpump condition.

[0021] In certain embodiments of the method of measuring overpump flow, the spring constant is about 15 Ib / in, the piston head area is about 1.227 sq.in and the orifice diameter is about 0.016 inch.

[0022] In certain embodiments of the method of measuring overpump flow, at least one ball switch is configured to detect displacement of the spring-loaded piston.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The disclosed embodiments will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed embodiments, wherein like designations denote like elements.

[0024] FIG. 1 is a schematic view of a diaphragm compressor system according to embodiments of the present disclosure.

[0025] FIG. 2 is a side cross sectional view of the flow measurement device in condition 1 with a spring-loaded piston in a first position according to embodiments of the present disclosure.

[0026] FIG. 3 is a side cross sectional view of the flow measurement device in condition 2 with the spring-loaded piston in a second position according to embodiments ofAttorney Docket No. P25349WOOO the present disclosure.

[0027] FIG. 4 is a side cross sectional view of the flow measurement device in condition 3 with the spring-loaded piston in a third position according to embodiments of the present disclosure.

[0028] FIG. 5A is a partial cross-sectional view of the flow measurement device with the spring-loaded piston in the third position according to embodiments of the present disclosure.

[0029] FIG. 5B is a partial perspective view of the flow measurement device with the spring-loaded piston in the third position according to embodiments of the present disclosure.

[0030] FIG. 6 is an exploded view of the flow measurement device according to embodiments of the present disclosure.

[0031] FIG. 7 is a graph depicting test results of overpump flow and flow measurement device pressure feedback according to embodiments of the present disclosure.

[0032] FIG. 8 is a graph depicting test results of overpump flow (125 cc / min to 5 cc / min) and flow measurement device pressure feedback (25 to 1 psi) according to embodiments of the present disclosure.

[0033] FIG. 9 is a graph depicting test results of overpump flow (7.5 cc / min to 4.5 cc / min) and flow measurement device pressure feedback (3.6 to 2.2 psi) according to embodiments of the present disclosure.

[0034] FIG. 10 is a side partial view of embodiments of the present disclosure having limit switches for feedback.DETAILED DESCRIPTION

[0035] Diaphragm compressors 1, as the one shown in FIG. 1, for example, use the displacement of a fixed volume of hydraulic oil to displace at least one metal diaphragm 7 for gas compression. The hydraulic oil may be displaced by a reciprocating hydraulic piston 5 which has a fixed displacement for a given model of the diaphragm compressor 1. The hydraulic piston 5 may be actively lubricated using the same oil and hence some oil from the oil cavity flows past the piston-sleeve interface and into the crank case 4 of the diaphragm compressor 1. An external oil injection pump 13 may provide an additional volume of oil (referred to as “injection oil”) into the oil cavity to (1) make up for the lubrication oil which isAttorney Docket No. P25349WOOO lost from a fixed volume oil cavity and (2) to ensure that the diaphragm 7 is in contact with a gas plate 8 at the end of the stroke of the hydraulic piston 5 in order to achieve maximum volumetric efficiency. The injection oil is added during the suction stroke of the diaphragm compressor 1. Hence after each suction stroke, the total volume of oil inside the oil cavity increases. When the piston 5 moves in the opposite direction in the discharge stroke, some of the oil is lost through the piston-sleeve interface (which also facilitates piston lubrication) and the rest flows out of an oil relief valve 17, also known as a “check valve,” mounted on the diaphragm compressor head 21. The oil flowing out of the oil relief valve 17 is termed as an overpump which is channeled back to the crank case 4 of the diaphragm compressor 1. Some embodiments may include a needle valve 46 used to bypass oil relief valve 17. Needle valve 46 may be opened to “prime” diaphragm compressor head 21 by allowing it to fill with oil after maintenance without building up hydraulic pressure, then closed before diaphragm compressor 1 is put into regular service.

[0036] The overpump flow is a brief intermittent flow which occurs with each rotation of the diaphragm compressor. For example, at 400 rpm of compressor speed (i.e. approximately 150 ms of cycle time for each single cycle of the compressor’s piston), the overpump flow from the oil relief valve may flow for approximately 3 to 4 milliseconds and for the rest of the approximately 146 to 147 milliseconds of each cycle no oil flows out of oil relief valve. The presence of an overpump flow is important to the function of the diaphragm compressor. The absence of an overpump flow can result in cavitation which leads to pistonsleeve failure, oil diaphragm failure and a triple diaphragm failure.

[0037] A “digital sight glass” or flow measurement device 10 according to embodiments of the present disclosure measures flow in a single device to provide visual and / or electronic feedback of overpump oil flow. In one embodiment, flow measurement device 10 may be configured to measure flow ranging from 2 - 4 cc / min (<0.25 drop / cycle with approximately 15 drops / cc) to 120 - 130 cc / min. Flow measurement device 10 can be configured for higher or lower flow rates. In some embodiments, for flow above 120 cc / min, the flow measurement device 10 will continue to function, with saturation of the feedback.

[0038] In certain embodiments, as the one shown in FIG. 1, flow measurement device 10 may measure overpump oil flow of a diaphragm compressor 1. The diaphragm compressor 1 may include an injection pump system 2, which may be driven off a primary crankshaft 3Attorney Docket No. P25349WOOO disposed in the ambient pressure crankcase 4 of diaphragm compressor 1. Crankshaft 3 may also drive a high pressure oil piston 5 that moves a column of oil through the suction and discharge cycles of diaphragm compressor 1. During the discharge cycle of diaphragm compressor 1, process gas compression occurs as the volume of oil is pushed upward to fill a lower oil plate cavity 6, exerting a uniform force against the bottom of a diaphragm 7 of diaphragm compressor 1. This deflects the diaphragm 7 into the upper gas plate cavity 8 that is filled with the process gas. The deflection of the diaphragm 7 against the upper gas plate cavity 8 first compresses the gas and then expels it through a gas discharge check valve 9. As the oil piston 5 reverses to begin the suction cycle, the diaphragm 7 is drawn downward to hug the lower oil plate cavity 6 while a gas inlet check valve 11 opens and fills the upper gas plate cavity 8 with a fresh charge of gas. The oil piston 5 passes through bottom dead center and begins its upward stroke, and the discharge cycle is repeated.

[0039] In some embodiments, injection pump system 2 may include an oil injection pump 13, at least one oil check valve 15 and an oil relief valve 17 coupled to the oil side of at least one diaphragm compressor head 21 of diaphragm compressor 1. The primary function of injection pump system is to maintain the required oil volume between the high-pressure oil piston 5 and diaphragm 7. in certain embodiments, during the diaphragm compressor's 1 suction stroke, a fixed volume of oil is injected into diaphragm compressor 1 by oil injection pump 13.

[0040] In certain embodiments, as discussed above, the oil volume between the high- pressure oil piston 5 and diaphragm 7 may be impacted by two modes of oil loss. The first mode of oil loss is annular leakage past the high-pressure oil piston 5 back to the ambient pressure crankcase 4. The second mode of oil loss is defined as “overpump,” which is oil flow through oil relief valve 17 back to the ambient pressure crankcase 4 which occurs every cycle during normal diaphragm compressor operation. Injector pump system 2 is designed and operated to maintain an “overpump” condition of work oil flow through oil relief valve 17 in each discharge cycle, in order to ensure that there is enough oil in the system for each stroke.

[0041] In certain embodiments, this overpump oil flow flowing from oil relief valve 17 is intermittent which is present for approximately 2 - 2.7% of the piston cycle (approximately 3 to 4 milliseconds out of the 150 millisecond period at 400 rpm).

[0042] The flow measurement device 10 may measure the overpump flow in a range.Attorney Docket No. P25349WOOOIn one embodiment, there may be four conditions which may be used to measure the overpump flow. The four conditions may be a first condition (Condition 1), a second condition (Condition 2), a third condition (Condition 3) and a fourth condition (Condition 4). Condition 1 (FIG. 2) may be a no or low overpump condition, which may correspond to the diaphragm compressor 1 being off, being in startup. Condition 2 (FIG. 3) may be a some or normal overpump condition, which may indicate a normal amount of overpump during operation of the compressor. Condition 3 (FIGS. 4-5B) may be a relief condition or saturation condition, which may indicate a greater yet still normal amount of overpump. Condition 4 (FIG. 2), represents a malfunction during operation of the diaphragm compressor such as a potential clog or obstruction preventing flow measurement device 10 from operating normally. Where overpump falls below a certain level, it may result in cavitation.

[0043] In certain embodiments, a constant flow of oil through the flow measurement device 10 may be indicative of a well primed diaphragm compressor 1 both during the startup and during the operation. It is also indicative of a properly functioning oil injection system 13 (injection pumps and check valves), piston seals (if incorporated), piston / sleeve (where piston seals are not used) and oil relief valve 17. Continuous monitoring of the overpump can help identify potential problems of the entire hydraulic system of the diaphragm compressor 1 and prevent catastrophic damage to both diaphragm compressor 1 and downstream gas system / plant. If such potential problems are identified using the status of the overpump oil flow and the diaphragm compressor 1 is shut down in a timely manner, expensive repairs may be avoided.

[0044] In certain embodiments, overpump oil flow flowing from oil relief valve 17 may be measured by flow measurement device 10 (FIG. 2) which may include an accumulator chamber 12. In some embodiments, accumulator chamber 12 may include a spring-loaded piston 18 biased by a spring 19.

[0045] Other embodiments may include an orifice such as an engineered orifice 14 disposed inside the spring-loaded piston 18. Still further embodiments may include a cylinder 16 within flow measurement device body 26 and with a close tolerance fit with spring-loaded piston 18. Other embodiments may include a filter screen 20.

[0046] In embodiments, flow measurement device 10 may further have an inlet 22 configured to receive overpump oil from oil relief valve 17, and an outlet 24 in fluidAttorney Docket No. P25349WOOO communication with inlet 22 and crankcase 4. In embodiments, oil may flow into the flow measurement device 10 through the inlet 22, and out through the outlet 24. In embodiments, cylinder 16 may have an inlet end 16A, an outlet end 16B and a cylindrical wall 16C. In embodiments, a variable volume cavity 52 may be defined by piston head 18A and inlet end 16A of cylinder 16, and the volume of variable volume cavity 52 may be measured within the space between piston head 18A and inlet end 16A of cylinder 16. The volume of variable volume cavity 52 may vary depending on the position of piston head 18A relative to inlet end 16A and outlet end 16B of cylinder 16. For example, the volume of variable volume cavity 52 may increase when of piston head 18A moves towards outlet end 16B.

[0047] In other embodiments, engineered orifice 14 may have an inlet end 14A and an outlet end 14B configured to fluidly couple inlet 22 and outlet 24. Engineered orifice 14 may further have an orifice diameter configured to allow oil flow through engineered orifice 14 and sized to measure lowest possible flow with minimum variation between a range of oil temperature (5 °C to 130 °C). Engineered orifice 14 may be a screw-in type insert and further include a lock nut 23 within inlet end 14A to secure the engineered orifice 14 in place. In some embodiments, as shown in FIGS. 2-6, engineered orifice 14 may be disposed in spring-loaded piston 18 with inlet end 14A in piston head 18A such that orifice 14 is in series with inlet 22 and outlet 24. In other embodiments, such as the embodiment of FIG. 10, engineered orifice 14 may be disposed outside of spring-loaded piston 18 such as parallel to inlet 22 and outlet 24. In some embodiments the orifice diameter is about 0.016 inch within a range of about 0.010 inch to about 0.020 inch.

[0048] In certain embodiments, spring-loaded piston 18 may have a piston head 18A and piston head area of about 1.227 sq.in. within a range of about 0.614 sq. in. to about 1.841 sq. in.. In some embodiments, the piston area is sized to provide feedback pressure of 1 psi minimum and 20-22 psi maximum.

[0049] In certain embodiments, spring 19 may have a spring constant and may be configured to bias the piston head 18A of spring-loaded piston 18 towards the inlet end 16A of cylinder 16. In some embodiments the spring constant is about 15 Ib / in. and may have a range of about 7.5 Ib / in to about 22.5 Ib / in.. In some embodiments, the spring constant may be sized to provide feedback pressure of 1 psi minimum and 20-22 psi maximum. Low pressure of 1 psi may be selected considering measurement resolution and noise immunity. HighAttorney Docket No. P25349WOOO pressure of 20-22 psi may be selected considering maximum back-pressure to the flow return path.

[0050] In some embodiments, the parameters of the engineered orifice 14, spring 19 and piston head 18A are selected to allow the piston to travel in a set range of conditions given the particular oil viscosity, overpump amount, and overpump frequency. These parameters may be different for different viscosities of oil or compressor operating frequency, or other operating conditions. In other words, for a given compressor system and oil, these parameters may be tuned to indicate to the user, the presence of condition 1, condition 2, and condition 3. In one embodiment, the size of the engineered orifice 14, spring constant, and the piston diameter are chosen to limit the backpressure to a range of about 1 psi to 20-22 psi, and total piston travel of about 1 inch. For example, in some embodiments, the spring constant is about 15 Ib / in, the piston head area is about 1.227 sq.in and the orifice diameter is about 0.016 inch.

[0051] As discussed below, flow measurement device 10 may accumulate overpump oil through inlet 22 during the time when oil flows and allows it to flow during the idle time of the cycle of diaphragm compressor 1 through engineered orifice 14. This action converts intermittent flow pulses through inlet 22 into a continuous flow stream and displaces spring- loaded piston 18 inside cylinder 16 to a position which is proportional to the oil flow. In certain embodiments, this position of spring-loaded piston 18 within cylinder 16 is measured indirectly by the oil pressure inside accumulator chamber 12. The oil pressure may be measured using a pressure transducer 28 mounted external to the flow measurement device 10. In one embodiment, pressure transducer 28 may be mounted at pressure transducer port 30.

[0052] As discussed above, accumulator chamber 12 may include spring-loaded piston 18, spring 19 and cylinder 16. Spring-loaded piston 18 and cylinder 16 may be match fit to provide a sealing surface, which under normal operating condition acts as a high resistance path for oil flow. Overpump oil flows into variable volume cavity 52 of accumulator chamber 12 with relatively high instantaneous flow. Engineered orifice 14, the interface between spring- loaded piston 18 and cylinder 16 provide high resistance to this high instantaneous flow and as a result, the oil accumulates in variable volume cavity 52 of accumulator chamber 12, and spring-loaded piston 18 is displaced towards outlet 24 of flow measurement device 10 proportionally. For the remainder of the cycle of oil piston 5, this accumulated oil flows from variable volume cavity 52 through engineered orifice 14, and, in condition 2, spring-loadedAttorney Docket No. P25349WOOO piston 18 is displaced towards inlet 22 of flow measurement device 10 by spring 19. In this embodiment, in condition 2, spring-loaded position 18 may be in an “in-range position” which may be defined as a position at which the leakage volume of the oil through engineered orifice 14 during “no-flow portion of the cycle” doesn’t exceed the volume of oil entering accumulator chamber 12 during “flow portion of the cycle.” In one embodiment, the range of the motion of spring-loaded position 18 may vary based on the flow (cc / cycle). For example, spring-loaded position 18 may displace about 0.001 inch to about 0.012 inch each cycle for flow between about 8 cc / min to about 100 cc / min. Oil relief valve 17 (FIG. 1) upstream of inlet 22 does not allow oil to flow in the reverse direction, so oil from outlet 24 does not flow to inlet 22 and hence the oil does not drain back to oil relief valve 17 during the idle time of the cycle.

[0053] In certain embodiments, if the inlet oil flow is higher than the engineered orifice leakage flow, the spring-loaded piston 18 continues to displace towards outlet 24 and as a result, spring 19 continues to compress. Due to increased compression, the oil pressure inside the accumulator chamber 12 rises proportionally. In embodiments, cylinder 16 may include at least one oil relief channel or passage 38 in its cylindrical wall 16C. Each at least one oil relief passage 38 may include a proximal end 38A and a distal end 38B. When spring-loaded piston 18 is displaced toward outlet end 16B of cylinder 16 such that piston head 18A is beyond the proximal end 38A of the at least one oil relief passage 38 (FIGS. 4, 5A, 5B), oil flows around the piston head 18A of spring-loaded piston 18 and through the at least one oil relief passage 38. In one embodiment, the at least one oil relief passage 38 may have sufficient orifice area for oil flow and hence the pressure is maintained to approximately 22 psi when piston head 18A reaches this position, effectively working as an oil relief valve. In condition 3, the position of the piston head 18A may be referred to as “relief position” or “saturation position” and, one embodiment, the distance of piston head 18A from top dead center may range between about 0.09 inch to about 0.12 inch. Below 22 psi when position of piston head 18A is not beyond the proximal end 38A of the at least one oil relief passage 38, the oil flows only through engineered orifice 14.

[0054] In some embodiments, as shown in FIGS. 2-6, cylinder 16 may be a cylinder insert 16 disposed in a central bore 26A of a flow measurement device body 26. Central bore 26A may have a bore wall 26B. The at least one oil relief passage 38 may be radially spaced, elongated longitudinal apertures (FIGS. 5A, 5B) disposed in cylindrical wall 16C such that theAttorney Docket No. P25349WOOO at least one oil relief passage 38 is defined at its outer diameter by bore wall 26B. As shown in FIGS. 4-5B, when piston head 18Ais beyond the proximal end 38A of the at least one oil relief passage 38 (FIGS. 4, 5A, 5B), oil flows around the piston head 18A of spring-loaded piston 18 and through the at least one oil relief passage 38 defined at its outer diameter by bore wall 26B.

[0055] In certain embodiments (not shown), cylinder 16 may be unitarily formed in flow measurement device body 26 and the at least one oil relief passage 38 may include radially spaced, elongated grooves or channels disposed in the cylindrical wall 16C of cylinder 16 such that the at least one oil relief passage 38 is defined at its outer diameter by the outer diameter of the radially spaced, elongated grooves or channels. In other embodiments, oil relief passage 38 can be any orifice uncovered by the piston, and for example, the oil flowing through the oil relief passage 38 may follow any path that leads back to crankcase 4.

[0056] In embodiments, the pressure inside accumulator chamber 12 may be measured using an externally mounted pressure gauge with color coding or a pressure transducer 28 mounted for example via pressure transducer port 30 for electronic feedback. Pressure transducer 28 may be in fluid communication with accumulator chamber 12 by being mounted directly on the pressure transducer port 30 of flow measurement device 10, or via a different port in fluid communication with the accumulator chamber 12.

[0057] In one embodiment, as discussed above, there may be four conditions which may be used to interpret the position of the piston / oil pressure within accumulator chamber 12 to measure the overpump flow: Condition 1) a no or low overpump condition (FIG. 2), Condition 2) a some or normal overpump condition (FIG. 3), Condition 3) a relief condition or a saturation condition (FIGS. 4, 5A, 5B); Condition 4) a malfunction condition

[0058] Condition 1 - in embodiments, a no or low overpump condition occurs when overpump flow at accumulator pressure is below a low threshold flow such as about 2 cc / min to 3 cc / min or 1 psi (FIG. 2). This condition arises when the oil flow through engineered orifice 14 is below a low threshold flow. Low threshold flow is termed as a minimum overpump flow which can be measured using any flow measurement device. Any overpump above a minimum overpump flow may be interpreted as a healthy overpump flow. However, due to practical constraints of pressure measurement in a dynamic condition, in one embodiment the threshold is set to 1 psi. It has been experimentally determined in oneAttorney Docket No. P25349WOOO embodiment that 1 psi equates to 2 cc / min (<0.25 drop / cycle) and 22 psi equates to 125 cc / min (~4.5 drops / cycle). Accordingly, low threshold flow may be set to about 2 cc / min or about 3 cc / min or 1 psi due to measurement constraints.

[0059] At or below minimum overpump flow, the instantaneous flow is low enough to leak through engineered orifice 14 and / or piston-cylinder 18, 16 clearance and hence oil doesn’t accumulate in variable volume chamber 52 to displace spring-loaded piston 18 towards outlet 24 and piston head 18A remains at bottom dead center (FIG. 2). Under normal operation of the compressor, minimum overpump flow may be an unhealthy overpump and the control system can be programmed to either turn off diaphragm compressor 1 or monitor other process parameters to determine the control action.

[0060] Condition-2: in some embodiments, some or normal overpump condition (FIG. 3) may occur when overpump flow is at accumulator pressure between a low threshold flow and a high threshold flow. In one embodiment, normal overpump condition includes a flow rate such as between about 2 cc / min (1 psi) and 125 cc / min (22 psi). This condition arises when the oil flow through engineered orifice 14 is above the low threshold flow, as defined above with respect to Condition 1. In other words, the volume of oil accumulated in flow measurement device 10 during each cycle is equivalent to the volume of oil which flows through engineered orifice 14 during idle time of the cycle. In this condition, the oil pressure inside accumulator chamber 12 is maintained to a level where the volume of overpump flow during each cycle is the same as the engineered orifice 14 flow, and hence the position of the piston 18 is also maintained such that piston head 18A is above the bottom dead center (FIG. 2) and below the proximal end 38A of the at least one oil relief channel 38. The rate of the oil leakage through the engineered orifice 14 may be proportional to the differential pressure across engineered orifice 14, and hence the pressure continues to rise to a level where there’s a balance of oil flow between the inlet oil and outlet oil through the engineered orifice 14. In one embodiment, the spring 19 may be preloaded with approximately 7.5 lb force when spring- loaded piston 18 is completely seated in the accumulator chamber 12 at bottom dead center (FIG. 2). Hence, any level of positive pressure in the accumulator chamber 12 is indicative of the presence of overpump flow.

[0061] Condition 3: in some embodiments, a relief condition or saturation condition may occur when overpump flow at accumulator pressure greater than or equal to a highAttorney Docket No. P25349WOOO threshold flow. In one embodiment, high threshold flow includes a flow rate such as about 125 cc / min (22 psi) (FIGS. 4, 5A, 5B). This condition arises when the oil flow through engineered orifice 14 is less than the overpump flow. In other words, the volume of oil accumulated in the flow measurement device 10 during each cycle is more than the volume of oil which flows through engineered orifice 14 during idle time of the cycle. In this condition, the spring-loaded piston 18 continues to move towards outlet 24, and pressure continues to rise. When piston head 18A of spring-loaded piston 18 reaches the proximal end of at least one relief passage 38, the oil flows around piston head 18A and through the at least one oil relief passage 38 to outlet 24 and the piston 18 displacement stops which results in maximum oil pressure. In one embodiment, maximum oil pressure may be 22 psi. This condition may be interpreted as relief condition or saturation condition.

[0062] Condition 4: in some embodiments, a malfunction condition may occur under any abnormal operating condition, for example a clogged fdter screen 20 or other mechanical failure which results in piston seizure; the pressure will rise above 25 psi or more, for example, above 35 psi. This may be interpreted as either a clogged filter screen 20 or flow blockage due to other mechanical failure. During a malfunction, such as a clogged filter screen 20, piston 18 may be in the position shown in FIG. 2, 3 or 4.

[0063] Exemplary test results are shown in FIGS. 7-9, corresponding to particular embodiments of the present invention. FIG. 7 indicates i) the proportional change in the feedback pressure (lighter line) with overpump flow (darker line) and ii) feedback saturation / maximum feedback (~25 psi) when oil is relieved through the at least one oil relief channel 38 with overpump flow is >= 130 cc / min.

[0064] FIG. 8 shows high resolution view of similar test between maximum and minimum pressure feedback (25 psi and 1 psi), specifically showing overpump flow (125 cc / min to 5 cc / min) (darker line) compared to maximum and minimum flow measurement device pressure feedback (25 to 1 psi) (lighter line).

[0065] FIG. 9 shows another high-resolution view of the overpump flow and flow measurement device 10 pressure feedback near the threshold flow, specifically showing overpump flow (7.5 cc / min to 4.5 cc / min) (darker line compared to flow measurement device pressure feedback (3.6 to 2.2 psi) (lighter line).

[0066] Embodiments of the disclosure may further include piston with non-metal sealsAttorney Docket No. P25349WOOO to provide positive sealing to i) avoid match-fit machining which may help achieving better precision for the threshold flow from device to device, ii) reduce manufacturing cost, iii) provide repairability.

[0067] Embodiments of the disclosure may further include a built-in a diaphragm style actuator. The flow measurement device 10 may be interfaced with an external system to trigger pneumatic valves for an auto priming module. In the auto priming module, the oil pressure signal from flow measurement device 10 is routed externally to trigger a pneumatic valve. Specifically, in one embodiment, a physical oil line is routed to a pneumatic valve such as a hydraulically piloted pneumatic valve. Intended trigger pressure is 22-23 psi. In other embodiments, the flow measurement device may include a spring-loaded diaphragm within the flow measurement device body 26 of the flow measurement device 10 to provide mechanical actuation to the pneumatic valve at desired oil pressure (commercially available pneumatic valve) which may be directly mounted on flow measurement device 10. The oil pressure signal from the flow measurement device 10 may actuate an oil relief valve to open at two or more different threshold pressures, for example two pressures, one corresponding to a priming condition for the diaphragm compressor, and one corresponding to an operating condition for a diaphragm compressor. Compared to a continuously variable oil relief valves, this operates under two conditions: a high pressure and a low pressure.

[0068] Embodiments of the disclosure may further include flow measurement device integrated into the body of the oil relief valve 17 for simplification and smaller envelope size.

[0069] Embodiments of the disclosure may use the flow measurement device 10 to support compressors such as those disclosed in commonly owned U.S. patents and applications 12,060,875 - Hydraulic Drive, Active Oil Injection System, And Controls Therefor; 12,385,480 - Active Oil Injection System For A Diaphragm Compressor; 17 / 840,937 - High- Throughput Diaphragm Compressor (Main Stage Valve); 18 / 516,210 - High-Throughput Diaphragm Compressor (Stacked Compressors); 11,867,169; 11,674,508; 12,055,135;12,025,118 - High-Throughput Diaphragm Compressor and 63 / 636,483 - Oil Sensor / Hydraulic Oil Sensor Sensing Diaphragm / Crack Detect Sensor Diaphragm / Leak Detect Sensor Diaphragm, all of such disclosures of which are incorporated by reference herein. Specifically, the flow measurement device 10 may be used in combination with the diaphragm compressor disclosed in 12,385,480 - Active Oil Injection System For A DiaphragmAttorney Docket No. P25349WOOOCompressor, wherein the flow measurement device 10 may replace the disclosed feedback mechanism for measuring the amount of overpump.

[0070] Still other embodiments of the disclosure may use flow measurement device 10 to support other compressors. In certain embodiments, (FIG. 10), a pneumatic piston actuator is used with a manifold in accordance with the present disclosure. This embodiment uses discrete position feedback of the spring-loaded piston 18 instead of oil pressure. Two ball plunger switches 42 may be used to detect piston position - one at top dead center and the other at bottom dead center (FIG. 10). Presence of the feedback from both position switches 42 may be indicative of maximum overpump flow and absence of the feedback from both position switches may be indicative of unhealthy overpump. An external relief valve (not shown) may provide a relief path when piston is at top dead center. In this embodiment, spacers 50 may be provided to prevent spring 19 from going solid when compressed.

[0071] In certain embodiments, a single assembly may provide i) a built-in relief function, ii) oil relief passages 38 for oil leakage flow through engineered orifice 14 and iii) an integral pressure transducer 28 to use as pressure feedback instead of piston position. The flow measurement device 10 may be housed in a manifold with a manifold cap housing the pressure transducer 28. In this embodiment, the piston may be made of a polytetrafluoroethylene (PTFE) material to provide interference fit.

[0072] In certain embodiments, a constant flow of oil through the flow measurement device 10 may be indicative of a well primed diaphragm compressor 1 both during the startup and during the operation. It is also indicative of a properly functioning oil injection system 2 (injection pumps and check valves), piston seals (if incorporated), piston / sleeve (where piston seals are not used) and oil relief valve 17. Continuous monitoring of the overpump can help identify potential problems of the entire hydraulic system of the diaphragm compressor 1 and prevent catastrophic damage to both diaphragm compressor 1 and downstream gas system / plant. If such potential problems are identified using the status of the overpump oil flow and the diaphragm compressor 1 is shut down in a timely manner, expensive repairs may be avoided.

[0073] It should be understood that the principles disclosed herein may be used to adapt to a system with higher or lower flow rates and / or pressures, and fluids other than oil. Therefore, any disclosure of a particular flow rate or pressure shall be interpreted as a nonAttorney Docket No. P25349WOOO limiting embodiment of this invention.

[0074] All of the features disclosed, claimed, and incorporated by reference herein, and all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. Each feature disclosed in this specification may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is an example only of a generic series of equivalent or similar features. Inventive aspects of this disclosure are not restricted to the details of the foregoing embodiments, but rather extend to any novel embodiment, or any novel combination of embodiments, of the features presented in this disclosure, and to any novel embodiment, or any novel combination of embodiments, of the steps of any method or process so disclosed.

[0075] Although specific examples have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement calculated to achieve the same purpose could be substituted for the specific examples disclosed. This application is intended to cover adaptations or variations of the present subject matter. Therefore, it is intended that the invention be defined by the attached claims and their legal equivalents, as well as the illustrative aspects. The above described embodiments are merely descriptive of its principles and are not to be considered limiting. Further modifications of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the inventive aspects.

[0076] It should be noted that the use of particular terminology when describing certain features or embodiments of the disclosure should not be taken to imply that the terminology is being re-defined herein to be restricted to include any specific characteristics of the features or embodiments of the disclosure with which that terminology is associated. Terms and phrases used in this application, and variations thereof, especially in the appended claims, unless otherwise expressly stated, should be construed as open-ended as opposed to limiting. As examples of the foregoing, the term “including” should be read to mean “including, without limitation,” “including but not limited to,” or the like; the term “comprising” as used herein is synonymous with “including,” “containing,” or “characterized by,” and is inclusive or open- ended and does not exclude additional, unrecited elements or method steps; the term “having” should be interpreted as “having at least”; the term “such as” should be interpreted as “such as,Attorney Docket No. P25349WOOO without limitation”; the term “includes” should be interpreted as “includes but is not limited to”; the term “example” is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof, and should be interpreted as “example, but without limitation”; adjectives such as “known,” “normal,” “standard,” and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass known, normal, or standard technologies that may be available or known now or at any time in the future; and use of terms like “preferably,” “preferred,” “desired,” or “desirable,” and words of similar meaning should not be understood as implying that certain features are critical, essential, or even important to the structure or function of the present disclosure, but instead as merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment.

[0077] Likewise, a group of items linked with the conjunction “and” should not be read as requiring that each and every one of those items be present in the grouping, but rather should be read as “and / or” unless expressly stated otherwise. Similarly, a group of items linked with the conjunction “or” should not be read as requiring mutual exclusivity among that group, but rather should be read as “and / or” unless expressly stated otherwise. The terms “about” or “approximate” and the like are synonymous and are used to indicate that the value modified by the term has an understood range associated with it, where the range may be ±20%, ±15%, ±10%, ±5%, or ±1%. The term “substantially” is used to indicate that a result (e.g., measurement value) is close to a targeted value, where close may mean, for example, the result is within 80% of the value, within 90% of the value, within 95% of the value, or within 99% of the value. Also, as used herein “defined” or “determined” may include “predefined” or “predetermined” and / or otherwise determined values, conditions, thresholds, measurements, and the like.

Claims

AMENDED CLAIMSreceived by the International Bureau on 11 June 2026 (11.06.2026)What Is Claimed Is:

1. A diaphragm compressor system, comprising:a diaphragm compressor comprising at least one compressor head, a crank case, and an overpump condition selected from one of a low overpump condition, a normal overpump condition, a relief or saturation overpump condition and a malfunction condition;an oil relief valve coupled to the at least one compressor head;a flow measurement device configured to measure overpump oil flow of the at least one compressor head by monitoring pressure within the flow measurement device, the flow measurement device comprising:an inlet configured to receive oil from the oil relief valve;an outlet in fluid communication with the inlet and the crank case;an accumulator chamber configured to accumulate oil from the inlet, the accumulator chamber comprising:a cylinder comprising an inlet end and an outlet end;a spring-loaded piston movable within the cylinder, the spring-loaded piston comprising a piston head comprising a piston head area;a spring configured to bias the piston towards the inlet end of the cylinder, the spring comprising a spring constant;a variable volume cavity defined by the inlet end of the cylinder and the piston head;an orifice comprising an orifice diameter, the orifice fluidly coupling the inlet and the outlet, wherein the orifice diameter is configured to allow oil to flow through the orifice; andat least one oil relief passage disposed within the outlet end of the cylinder, the oil relief passage comprising a proximal end, wherein the spring- loaded piston is configured to be displaced towards the outlet end of the cylinder and beyond the proximal end of the at least one oil relief passage during the relief or saturation overpump condition, and allow at least a portion of the oil to exit the accumulator chamber by bypassing the piston;AMENDED SHEET (ARTICLE 19)24a pressure transducer in fluid communication with the accumulator chamber configured to measure the pressure of oil in the accumulator chamber; andwherein the piston head area and the spring constant are configured to allow the spring-loaded piston to be displaced within the cylinder to a position which is proportional to the oil flow during the normal overpump condition.

2. The diaphragm compressor system of claim 1, wherein the cylinder comprises a cylindrical wall, and the at least one oil relief passage is disposed within the cylindrical wall.

3. The diaphragm compressor system of claim 1, wherein the flow measurement device comprises a flow measurement device body comprising a central bore, wherein the cylinder is a cylinder insert disposed within the central bore of the flow measurement device body, wherein the cylinder insert comprises a cylindrical wall, and the at least one oil relief passage comprises radially spaced, elongated longitudinal apertures disposed in the cylindrical wall of the cylinder insert.

4. The diaphragm compressor system of claim 1, wherein the orifice is disposed within the piston.

5. The diaphragm compressor system of claim 1, wherein the orifice is disposed parallel to the piston.

6. The diaphragm compressor system of claim 1, further comprising a filter screen between the inlet and the piston.

7. The diaphragm compressor system of claim 1, wherein the spring-loaded piston is configured to be disposed at the inlet end of the cylinder during the low or malfunction overpump conditions.

8. The diaphragm compressor system of claim 1, wherein the spring-loaded piston isAMENDED SHEET (ARTICLE 19)configured to be disposed between the inlet end and the outlet end of the cylinder during the normal overpump condition.

9. The diaphragm compressor system of claim 1 wherein the spring constant is about 15 Ib / in, the piston head area is about 1.227 sq.in and the orifice diameter is about 0.016 inch.

10. The diaphragm compressor system of claim 1, further comprising at least one ball switch configured to detect displacement of the spring-loaded piston.

11. A method of measuring overpump flow of a diaphragm compressor system, the method comprising:providing a diaphragm compressor comprising at least one compressor head, a crank case, and an overpump condition selected from one of a low overpump condition, a normal overpump condition, a relief or saturation overpump condition, and a malfunction condition; coupling an oil relief valve to the at least one compressor head;measuring overpump oil flow of the at least one compressor head by monitoring pressure within a flow measurement device, the flow measurement device comprising:an inlet configured to receive oil from the oil relief valve;an outlet in fluid communication with the inlet and the crank case;an accumulator chamber configured to accumulate oil from the inlet, the accumulator chamber comprising:a cylinder comprising an inlet end and an outlet end;a spring-loaded piston movable within the cylinder, the spring-loaded piston comprising a piston head comprising a piston head area;a spring configured to bias the piston towards the inlet end of the cylinder, the spring comprising a spring constant;a variable volume cavity defined by the inlet end of the cylinder and the piston head;an orifice comprising an orifice diameter, the orifice fluidly coupling the inlet and the outlet, wherein the orifice diameter is configured to allow oil to flow through the orifice; andat least one oil relief passage disposed within the outlet end of the cylinder, the oil relief passage comprising a proximal end, wherein the spring- loaded piston is configured to be displaced towards the outlet end of the cylinder and beyond the proximal end of the at least one oil relief passage during the relief or saturation overpump condition, and allow at least a portion of the oil to exit the accumulator chamber by bypassing the piston;coupling a pressure transducer with the accumulator chamber configured to measure the pressure of oil in the accumulator chamber; andwherein the piston head area and the spring constant are configured to allow the spring-loaded piston to be displaced within the cylinder to a position which is proportional to the oil flow during the normal overpump condition.

12. The method of claim 11, wherein the cylinder comprises a cylindrical wall, and the at least one oil relief passage is disposed within the cylindrical wall.

13. The method of claim 11, wherein the flow measurement device comprises a flow measurement device body comprising a central bore, wherein the cylinder is a cylinder insert disposed within the central bore of the flow measurement device body, wherein the cylinder insert comprises a cylindrical wall, and the at least one oil relief passage comprises radially spaced, elongated longitudinal apertures disposed in the cylindrical wall of the cylinder insert.

14. The method of claim 11 , wherein the orifice is disposed within the piston.

15. The method of claim 11 , wherein the orifice is disposed parallel to the piston.

16. The method of claim 11 , further comprising a filter screen between the inlet and the piston.

17. The method of claim 11, wherein the spring-loaded piston is configured to be disposed at the inlet end of the cylinder during the low or malfunction overpump condition.AMENDED SHEET (ARTICLE 19)18. The method of claim 11, wherein the spring-loaded piston is configured to be disposed between the inlet end and the outlet end of the cylinder during the normal overpump condition.

19. The method of claim 11 , wherein the spring constant is about 15 Ib / in, the piston head area is about 1.227 sq.in and the orifice diameter is about 0.016 inch.

20. The method of claim 11, further comprising at least one ball switch configured to detect displacement of the spring-loaded piston.

Images