A method for regulating the flow of a diaphragm compressor

Abstract

The present application relates to the technical field of diaphragm compressor, and particularly relates to a diaphragm compressor flow regulating method. The specific method comprises the following steps: connecting the oil side membrane cavity to the liquid accumulator oil cavity of a plurality of liquid accumulators through pipelines; calculating Δq v ; calculating the required regulating flow of the diaphragm compressor; comparing the required regulating flow with Δq v of the liquid accumulator, opening the control valve of the liquid accumulator matched with the required regulating flow of the diaphragm compressor; obtaining the actual flow of the diaphragm compressor after the diaphragm compressor is adjusted and stabilized; and terminating the regulating program when the actual flow of the diaphragm compressor satisfies the condition of (1-λ)q g ≤q≤(1+λ)q g . The present application solves the problems of insufficient pressurization capacity, unbalanced pressure ratio distribution and poor working condition adaptability of the diaphragm compressor in the existing hydrogenation station application scenario by adjusting the flow of a certain stage of the diaphragm compressor for hydrogenation station.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of diaphragm compressors, and particularly relates to a diaphragm compressor flow regulation method. BACKGROUND

[0002] Hydrogen energy is a kind of secondary energy with great potential, which can power hydrogen fuel cell vehicles and is an important part of clean energy. Hydrogen refueling stations are key infrastructure in hydrogen energy applications, which can efficiently and cleanly supply hydrogen, support fast hydrogen refueling for fuel cell vehicles, and promote the use of renewable energy and environmental protection. Diaphragm compressors are crucial in hydrogen refueling stations due to their excellent sealing and high gas cleanliness, effectively improving hydrogen compression efficiency. In the high-pressure environment of hydrogen refueling stations, diaphragm compressors pressurize hydrogen from low pressure to the required high pressure, ensuring stable and safe hydrogen supply for fuel cell vehicles. Especially in the 70MPa hydrogen refueling process, diaphragm compressors are popular due to their durability, efficiency, and safety, supporting efficient operation of hydrogen refueling stations. Considering safety, external hydrogen supply hydrogen refueling stations are increasingly common, and long-pipe trailers are also a common way to supply hydrogen to hydrogen storage tanks in hydrogen refueling stations. Since the pressure of the long-pipe trailer is low after refueling, two-stage diaphragm compressors are needed for pressurization during refueling.

[0003] The existing hydrogen refueling station application scenario is a typical variable working condition. During the hydrogen refueling process, the hydrogen pressure in the long-pipe trailer continuously decreases, while the pressure in the hydrogen storage tank continuously increases, resulting in a continuously changing total pressure ratio of the two-stage diaphragm compressor. During the pressurization stage, the primary pressure ratio of the diaphragm compressor is limited by the effective suction volume ratio of the two-stage compressor, with a small change range, while the secondary pressure ratio is greatly affected by the working condition. Since the primary pressure ratio is not adjustable, it limits the pressurization capacity, resulting in the hydrogen pressure in the long-pipe trailer failing to reach the required pressure, reducing economic efficiency. At the same time, since the diaphragm compressor operates at a high pressure ratio, the primary pressure ratio is much smaller than the secondary pressure ratio, resulting in an unbalanced distribution of the primary and secondary pressure ratios during actual operation, deviating far from the design point, reducing compressor efficiency and stability. SUMMARY

[0004] To solve the problems of insufficient pressurization capacity, unbalanced pressure ratio distribution, and poor working condition adaptability of diaphragm compressors in existing hydrogen refueling station application scenarios, the present application provides a diaphragm compressor flow regulation method.

[0005] The present application adjusts the flow of a certain stage of diaphragm compressor, realizes the redistribution of the primary and secondary pressure ratios, and ensures that the diaphragm compressor is always in a stable, efficient, and safe operating state under the typical variable working conditions of hydrogen refueling stations.

[0006] To achieve the above-mentioned purpose, the technical solution of the present application is as follows.

[0007] The application provides a diaphragm compressor flow regulating method, which is applied to a diaphragm compressor, and the diaphragm compressor comprises a membrane head structure, and the membrane head structure has an oil side membrane cavity; the specific method comprises the following steps:

[0008] The oil side membrane cavity is connected with a plurality of liquid accumulators through pipelines; each of the liquid accumulators has a liquid accumulator oil cavity, and the outlet of each of the liquid accumulator oil cavities is provided with a control valve; the volume of hydraulic oil in each of the liquid accumulator oil cavities entering the oil side membrane cavity and the volume of hydraulic oil expanding in the oil side membrane cavity when the diaphragm compressor ends the suction are obtained, so that the controllable flow of each of the liquid accumulators in the working cycle of the diaphragm compressor is calculated.

[0009] The required controllable flow of the diaphragm compressor is obtained; the required controllable flow of the diaphragm compressor is compared with the controllable flow of each of the liquid accumulators in the working cycle of the diaphragm compressor, and the control valve of the liquid accumulator matched with the required controllable flow of the diaphragm compressor is opened.

[0010] After the diaphragm compressor is adjusted to stably work, the actual flow of the diaphragm compressor is obtained; when the actual flow of the diaphragm compressor meets the following conditions, the adjusting program is terminated:

[0011] (1-λ)q g ≤q≤(1+λ)q g ; wherein λ is a control margin factor, q g is the target flow of the diaphragm compressor, and q is the actual flow of the diaphragm compressor.

[0012] In view of the deficiencies of the existing diaphragm compressor flow regulating technology, the application provides a new scheme for regulating the flow of the diaphragm compressor based on the specific oil overflow and oil supplement mechanism of the diaphragm compressor and the compressibility of the hydraulic oil, the flow of a certain stage of the diaphragm compressor is adjusted, the redistribution of the pressure ratios of the first and second stages is realized, and thus the diaphragm compressor is ensured to be in a stable, efficient and safe running state under the typical variable working conditions of a hydrogenation station. The application mainly realizes the stepless regulation of the flow of the diaphragm compressor by increasing the number of the liquid accumulators in parallel, the energy loss is small during the flow regulation, the system stability is not affected, and the negative influence on the service life of the compressor is also avoided.

[0013] Preferably, 0.1 < λ < 0.15.

[0014] Preferably, when the actual flow of the diaphragm compressor does not meet the condition (1-λ)q g ≤q≤(1+λ)q g , the following steps are performed:

[0015] When q < (1-λ)q gWhen q

[0016] When q g ≤q≤(1+λ)q g , the adjusting procedure is terminated.

[0017] When q g ≤q≤(1+λ)q g , the following steps are performed:

[0018] When q g , the step of calculating the required regulating flow of the diaphragm compressor is performed again, and the calculated required regulating flow of the diaphragm compressor is compared with the available regulating flow of each accumulator of the diaphragm compressor in the working cycle until the actual flow of the diaphragm compressor satisfies the condition of q g ≤q≤(1+λ)q g , the control valve of the accumulator matching the required regulating flow of the diaphragm compressor is opened, and the adjusting procedure is terminated.

[0019] Preferably, the formula for calculating the available regulating flow of one accumulator of the diaphragm compressor in the working cycle is as follows:

[0020] Δq v =(Δv oil +Δv oil-e )λ T λ p λ v-e n;

[0021] wherein Δq v represents the available regulating flow of one accumulator of the diaphragm compressor in the working cycle; Δv oil represents the volume of hydraulic oil in the oil chamber of one accumulator of the diaphragm compressor entering the oil-side membrane chamber at the end of suction; Δv oil-e represents the volume of hydraulic oil in the oil-side membrane chamber expanding at the end of suction; λ T represents the temperature coefficient caused by the intake heating of the diaphragm compressor; λ p represents the pressure coefficient caused by the resistance loss of the diaphragm compressor; and λ v-e represents the gas expansion coefficient caused by the clearance volume of the diaphragm compressor; and n represents the rotational speed of the diaphragm compressor.

[0022] Preferably, each of the liquid reservoirs has a gas cavity; the method for obtaining the volume of hydraulic oil in the oil-side diaphragm cavity from one of the liquid reservoirs at the end of suction of the diaphragm compressor is as follows:

[0023] The volume of the gas cavity of the liquid reservoir, the oil overflow pressure of the diaphragm compressor, and the oil pressure at the end of suction of the diaphragm compressor are obtained to calculate the volume of hydraulic oil in the oil-side diaphragm cavity from one of the liquid reservoirs at the end of suction of the diaphragm compressor, denoted as Δv oil . Δv oil The calculation formula is as follows:

[0024] wherein Δv oil represents the volume of hydraulic oil in the oil-side diaphragm cavity from one of the liquid reservoirs at the end of suction of the diaphragm compressor; v o represents the volume of the gas cavity of the liquid reservoir; p0represents the oil overflow pressure of the diaphragm compressor; p1represents the oil pressure at the end of suction of the diaphragm compressor; and m represents the process index.

[0025] Preferably, the method for obtaining the volume of hydraulic oil in the oil-side diaphragm cavity at the end of suction of the diaphragm compressor is as follows:

[0026] The oil overflow pressure of the diaphragm compressor, the oil pressure at the end of suction of the diaphragm compressor, and the total volume of all hydraulic oil in the oil-side diaphragm cavity and the liquid reservoir oil cavity connected thereto of the diaphragm compressor at the end of exhaust of the diaphragm compressor are obtained to calculate the volume of hydraulic oil in the oil-side diaphragm cavity at the end of suction of the diaphragm compressor, denoted as Δv oil-e ; the calculation formula of Δv oil-e is as follows:

[0027] wherein Δv oil-e represents the volume of hydraulic oil in the oil-side diaphragm cavity at the end of suction of the diaphragm compressor; p0represents the oil overflow pressure of the diaphragm compressor; p1represents the oil pressure at the end of suction of the diaphragm compressor; β represents the bulk modulus of hydraulic oil; and v oil-tdc represents the total volume of all hydraulic oil in the oil-side diaphragm cavity and the liquid reservoir oil cavity connected thereto of the diaphragm compressor at the end of exhaust of the diaphragm compressor.

[0028] Preferably, the liquid reservoir comprises a liquid reservoir shell, a floating piston, and a liquid reservoir end cover; the liquid reservoir end cover is fixedly connected with the liquid reservoir shell and is used for sealing the liquid reservoir shell; and the floating piston is slidably arranged in the liquid reservoir shell and is configured to divide the internal space of the liquid reservoir shell and the liquid reservoir end cover to form the liquid reservoir oil cavity and the liquid reservoir gas cavity.

[0029] Preferably, the oil reservoir oil cavity has an oil path, and a control valve of the oil reservoir is arranged on the corresponding oil path; an end cover air suction pipeline is arranged on the oil reservoir air cavity, and an end cover air suction valve is arranged on the end cover air suction pipeline.

[0030] Preferably, the oil reservoir end cover and the oil reservoir shell are fixed through a second connecting piece; and the end cover air suction pipeline and the oil reservoir end cover are fixed through a third connecting piece.

[0031] Preferably, the diaphragm compressor further comprises a control system, wherein the control system comprises a PLC control module, an oil pressure sensor and a flow meter; the flow meter is connected with an exhaust pipeline of the diaphragm compressor; the oil pressure sensor is connected with an oil side membrane cavity of the diaphragm compressor; and the PLC control module is respectively connected with the oil pressure sensor, the flow meter and a control valve of the oil reservoir.

[0032] The diaphragm compressor has the following beneficial effects:

[0033] 1. The diaphragm compressor has a unique oil overflow and oil supplement mechanism, and the hydraulic oil is compressible, so that a new scheme for adjusting the flow of the diaphragm compressor is provided. The diaphragm compressor flow can be effectively adjusted, the flow of a certain stage of the diaphragm compressor is adjusted, the primary and secondary pressure ratios are redistributed, and the diaphragm compressor is always in a stable, efficient and safe operating state under the typical variable working conditions of the hydrogenation station. The method can improve the compression capacity, efficiency and stability of the compressor, thereby improving the economic benefit and operation reliability of the hydrogenation station.

[0034] 2. The number of different volume oil reservoirs is increased in parallel to realize stepless adjustment of the flow of the diaphragm compressor, the energy loss is small during flow adjustment, the system stability is not affected, and the negative impact on the service life of the compressor is also small.

[0035] 3. The diaphragm compressor has a simple structure, convenient installation and low cost, and can exhibit good performance and high operability during flow adjustment. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a schematic diagram of a membrane head structure of the diaphragm compressor.

[0037] Figure 2 is a structural schematic diagram of the oil reservoir.

[0038] Figure 3 is a state diagram of the end of air suction of the flow adjustment system when the control valve is not opened in an embodiment of the diaphragm compressor.

[0039] Figure 4 is a state diagram of the end of air suction of the flow adjustment system when the control valve is opened in an embodiment of the diaphragm compressor.

[0040] Figure 5 Figure 1 is a schematic diagram of a flow regulating system with three liquid reservoirs connected in parallel in an embodiment of the present application.

[0041] Reference signs:

[0042] 10, die structure; 101, air-side die head; 102, die head exhaust valve; 103, die head suction valve; 104, air distribution disc; 105, diaphragm; 106, oil distribution disc; 107, oil-side die head; 108, die head piston; 109, first connecting piece; 110, air-side die cavity; 111, oil-side die cavity; 112, oil overflow hole; 113, oil supplement hole.

[0043] 20, liquid reservoir; 201, liquid reservoir shell; 202, floating piston; 203, liquid reservoir end cover; 204, end cover suction valve; 205, end cover suction pipeline; 206, second connecting piece; 207, third connecting piece; 208, liquid reservoir air cavity; 209, liquid reservoir oil cavity; 210, sealing element; 211, oil path.

[0044] 30, control system; 301, PLC control module; 302, oil pressure sensor; 303, flow meter. DETAILED DESCRIPTION

[0045] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0046] Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application.

[0047] The diaphragm compressor is a specially designed positive displacement compression device, which mainly realizes the compression and delivery of gas through the reciprocating deformation movement of the diaphragm in the cylinder. Due to its unique structure and working principle, including high compression ratio and excellent sealing performance, it can effectively prevent the contamination of hydraulic oil and solid impurities to the compressed gas, so that it can be widely applied to the work of hydrogenation station.

[0048] As shown in Figure 1 , the die head structure of the diaphragm compressor includes the air-side die head 101, the die head exhaust valve 102, the die head suction valve 103, the air distribution disc 104, the diaphragm 105, the oil distribution disc 106, the oil-side die head 107, the die head piston 108 and the first connecting piece 109.

[0049] The gas-side membrane head 101 and the oil-side membrane head 107 are fixedly connected by the first connecting member 109; the gas-side membrane head 101 and the oil-side membrane head 107 are combined to form a mounting cavity; the gas distribution disc 104, the diaphragm 105 and the oil distribution disc 106 are arranged in the mounting cavity, and the diaphragm 105 is arranged between the gas distribution disc 104 and the oil distribution disc 106. Specifically, the first connecting member 109 is a cylinder head connecting stud.

[0050] With the first connecting member 109 gradually pressing the gas-side membrane head 101 and the oil-side membrane head 107, the two ends of the gas distribution disc 104 and the oil distribution disc 106 are tightly matched to press and fix the diaphragm 105, so that the diaphragm 105 is fixed between the gas distribution disc 104 and the oil distribution disc 106; at this time, the diaphragm 105 divides the inner cavity surrounded by the gas distribution disc 104 and the oil distribution disc 106 into a gas-side membrane cavity 110 and an oil-side membrane cavity 111; the gas-side membrane cavity 110 is arranged on the side close to the gas distribution disc 104; the oil-side membrane cavity 111 is arranged on the side close to the oil distribution disc 106. Specifically, the space surrounded by the diaphragm 105 and the gas distribution disc 104 is the gas-side membrane cavity 110, and the space surrounded by the diaphragm 105 and the oil distribution disc 106 is the oil-side membrane cavity 111.

[0051] Specifically, one side of the gas-side membrane head 101 has a first groove body, and the gas distribution disc 104 is arranged on one side of the first groove body; one side of the oil-side membrane head 107 has a second groove body, and the oil distribution disc 106 is arranged on one side of the second groove body. The gas-side membrane head 101 and the gas distribution disc 104 are provided with a communication exhaust hole and a suction hole, one end of the exhaust hole and the suction hole is communicated with the gas-side membrane cavity 110; the exhaust hole is provided with a membrane head exhaust valve 102 at one end of the gas distribution disc 104; the suction hole is provided with a membrane head suction valve 103 at one end of the gas distribution disc 104. The membrane head exhaust valve 102 is a one-way exhaust valve; the membrane head suction valve 103 is a one-way suction valve. The membrane head exhaust valve 102 and the membrane head suction valve 103 are used to control the one-way exhaust and one-way suction of the gas-side membrane cavity 110. Wherein, the exhaust hole is connected with a membrane head exhaust pipeline; the suction hole is connected with a membrane head suction pipeline.

[0052] Specifically, the space surrounded by the oil distribution plate 106 and the oil side membrane head 107 is a buffer cavity, which can be regarded as part of the oil side membrane cavity; the oil distribution plate 106 has a plurality of passages; the buffer cavity is in communication with the oil side membrane cavity 111 through the plurality of passages; the oil side membrane head 107 has a piston hole in which a membrane head piston 108 is arranged; the oil side membrane head 107 has an oil overflow hole 112 on the side edge, and an oil overflow valve is arranged on the oil overflow hole 112; the oil pressure in the oil side membrane cavity 111 is controlled through the oil overflow valve. Specifically, the oil side membrane head 107 has an oil supplement hole 113 on the side edge away from the oil overflow hole 112, and an oil supplement pipeline is connected to the oil supplement hole 113 to supplement oil. Specifically, the membrane head piston 108 is connected to a crank connecting rod mechanism, the crank connecting rod mechanism is connected to an external motor, and the crank connecting rod mechanism is driven by the external motor to drive the membrane head piston 108 to move. The crank connecting rod mechanism is a prior art, which is mainly driven by an external motor to drive the membrane head piston 108 to move, and the specific structure will not be described here.

[0053] The working principle of the membrane head structure of the diaphragm compressor is as follows:

[0054] The diaphragm compressor drives the crank connecting rod mechanism by an external motor, thereby driving the membrane head piston 108 to move. When the membrane head piston 108 reaches the top dead center, the diaphragm 105 deforms towards the gas side membrane cavity 110 due to the extrusion of the hydraulic oil, so that the space of the gas side membrane cavity 110 is reduced, the gas is compressed and discharged. During the entire gas compression process, the hydraulic oil pressure and the gas pressure increase synchronously. When the diaphragm 105 is tightly attached to the surface of the gas distribution plate 104 on one side of the gas side membrane head 101, the gas discharge ends, the membrane head piston 108 reaches the top dead center, and the hydraulic oil pressure reaches the set maximum oil overflow pressure. The excess hydraulic oil is discharged through the oil overflow valve.

[0055] Subsequently, the membrane head piston 108 starts to move towards the bottom dead center, the diaphragm 105 gradually returns to the equilibrium position, the space of the gas side membrane cavity 110 increases, and the residual gas starts to expand. When the gas pressure in the gas side membrane cavity 110 is lower than the gas pressure in the inlet pipe, the membrane head suction valve 103 opens, and the suction process starts.

[0056] During the entire gas expansion and suction process of the diaphragm compressor, the hydraulic oil pressure and the gas pressure change coordinately. When the membrane head piston 108 reaches the bottom dead center, the suction process ends. There is leakage in the diaphragm compressor during operation, and excess hydraulic oil is discharged from the oil overflow valve during gas discharge. The amount of hydraulic oil discharged from the oil overflow valve is substantially equal to the oil supplement amount.

[0057] At present, the diaphragm compressor has problems of insufficient pressurization capacity caused by pressure ratio change, unbalanced pressure ratio distribution and poor working condition adaptability in existing hydrogenation station application scenarios.

[0058] For the problem of insufficient pressurization capacity caused by pressure ratio change: During the hydrogen filling process, the pressure in the long tube trailer continuously decreases, and the pressure in the hydrogen storage tank continuously rises. The total pressure ratio of the two-stage diaphragm compressor changes constantly. The primary pressure ratio is limited by the effective suction volume ratio of the two-stage compressor, with a small change range and no adjustment, which limits the pressurization capacity of the primary stage during the pressurization stage, and the hydrogen pressure in the long tube trailer cannot be reduced to the required pressure, thereby reducing the economic benefits.

[0059] For the problem of unbalanced pressure ratio distribution: Currently, the diaphragm compressor operates at a high pressure ratio, with the primary pressure ratio much smaller than the secondary pressure ratio, resulting in an unbalanced distribution of the primary and secondary pressure ratios. This imbalance causes the actual operating conditions of the compressor to deviate far from the design point, thereby reducing the efficiency and stability of the compressor.

[0060] For the problem of poor adaptability to working conditions: Due to the typical variable working conditions of hydrogen filling stations, the secondary pressure ratio is greatly affected by the working conditions, while the primary pressure ratio is not adjustable, which makes it difficult for the diaphragm compressor to adapt to changes in working conditions. This not only affects the pressurization effect and economic benefits of the compressor, but also may have adverse effects on the long-term stable operation of the compressor.

[0061] Since diaphragm compressors are widely used in hydrogen filling stations, petroleum and chemical industries, it is important for diaphragm compressors to be able to handle changes in flow to adapt to changes in gas demand, ensure that the output of the diaphragm compressor matches the load, improve energy efficiency, and reduce energy waste. At the same time, through flow regulation, the service life of the machine can be extended, and the system pressure can be kept stable. Through flow regulation, the diaphragm compressor can operate efficiently and stably under various working conditions.

[0062] Currently, the main flow regulation methods for diaphragm compressors are bypass regulation and variable speed regulation. Bypass regulation is achieved by setting a bypass valve to connect the exhaust and intake pipelines, and introducing part of the compressed gas from the exhaust side of the diaphragm compressor back to the intake side, thereby reducing the effective flow of the diaphragm compressor and regulating the flow. Variable speed regulation is achieved by controlling the speed of the diaphragm compressor drive motor to regulate the flow, achieving continuous flow regulation.

[0063] However, the main disadvantage of bypass regulation of diaphragm compressor flow is that the energy loss is large, and due to the cyclic compression of bypass gas, the actual energy efficiency is reduced, increasing energy waste. In addition, bypass regulation may cause unstable system pressure, especially in cases where the load changes greatly, which may cause fluctuations in the operating efficiency of the compressor, thereby affecting the stability of the entire system.

[0064] The main disadvantage of the variable speed regulation flow of the diaphragm compressor is that the adjustable range is very narrow, generally the lowest 30Hz of the frequency conversion, that is, the flow regulation range can only be between 60% and 100%; at the same time, the lubrication of the moving part is insufficient under the condition of low speed operation of the diaphragm compressor, which accelerates the wear of the moving part and reduces the service life of the compressor. In addition, the continuous adjustment of the frequency converter causes great impact on the power grid, which easily causes vibration of the diaphragm compressor system.

[0065] In summary, the diaphragm compressor faces the technical problems of energy loss, unstable system pressure, narrow adjustable range, insufficient lubrication of the moving part, and power grid impact and vibration in the flow regulation, which limits the performance and efficiency of the diaphragm compressor and has an adverse effect on the stable operation and economic benefit of the hydrogenation station.

[0066] In view of the deficiencies of the existing diaphragm compressor flow regulation technology, the present application provides a new scheme for regulating the flow of the diaphragm compressor based on the unique oil overflow and oil supplement mechanism of the diaphragm compressor and the compressibility of the hydraulic oil. The present application can effectively regulate the flow of the diaphragm compressor, adjust the flow of a certain stage of the diaphragm compressor, realize the redistribution of the pressure ratio of the first and second stages, and thus ensure that the diaphragm compressor is always in a stable, efficient and safe operating state under the typical variable working conditions of the hydrogenation station.

[0067] The method of the present application can improve the boosting capacity, efficiency and stability of the compressor, thereby improving the economic benefit and operation reliability of the hydrogenation station.

[0068] The technical solutions of the present application will be further described below through specific examples.

[0069] In each of the following examples, the method is a conventional method unless otherwise specified; the reagents and materials can be purchased on the market unless otherwise specified.

[0070] The structure of the liquid accumulator 20 is shown in Figure 2 The liquid accumulator 20 has a liquid accumulator oil cavity 209, and the outlet of the liquid accumulator oil cavity 209 is provided with a control valve; the oil side membrane cavity 111 is connected to the plurality of liquid accumulator oil cavities 209 through pipelines.

[0071] In a preferred embodiment, as Figure 2 The liquid accumulator 20 includes a liquid accumulator shell 201, a floating piston 202 and a liquid accumulator end cover 203; the liquid accumulator end cover 203 is fixedly connected with the liquid accumulator shell 201 and is used for sealing the liquid accumulator shell 201; the floating piston 202 is slidably arranged in the liquid accumulator shell 201 and is configured to separate the internal space of the liquid accumulator shell 201 and the liquid accumulator end cover 203 to form the liquid accumulator oil cavity 209 and the liquid accumulator gas cavity 208.

[0072] Specifically, before the diaphragm compressor flow regulation, several volume different reservoirs can be connected in parallel, and the different volume of the reservoirs is designed to meet various flow requirements, so as to facilitate flexible regulation. When the compressor needs flow regulation, the operator can selectively open the control valve to connect the oil cavity 209 of several reservoirs with the oil side membrane cavity 111 of the diaphragm compressor for flow regulation according to the calculated required regulation flow.

[0073] In a preferred embodiment, the reservoir oil cavity 209 has an oil passage 211, and the control valve is arranged on the corresponding oil passage 211; the reservoir gas cavity 208 is provided with an end cover suction pipeline 205, and the end cover suction pipeline 205 is provided with an end cover suction valve 204.

[0074] Specifically, before the reservoir oil cavity 209 is connected with the oil side membrane cavity 111 of the diaphragm compressor through the control valve, the reservoir needs to store a certain pressure of high-pressure gas and hydraulic oil through the end cover suction pipeline 205 and the oil passage 211 respectively. Then, the reservoir oil cavity 209 is connected with the oil side membrane cavity 111 of the diaphragm compressor through the control valve, which is used for regulating the flow of the diaphragm compressor.

[0075] In a preferred embodiment, the reservoir end cover 203 is fixed with the reservoir shell 201 through the second connecting piece 206; the end cover suction pipeline 205 is fixed with the reservoir end cover 203 through the third connecting piece 207.

[0076] Specifically, the reservoir shell 201 is connected with the reservoir end cover 203 through the second connecting piece 206, the connection between the reservoir end cover 203 and the end cover suction pipeline 205 is realized through the third connecting piece 207 between the flange on the end cover suction pipeline 205 and the reservoir end cover 203, and the end cover suction valve 204 is installed by being pressed by the end cover suction pipeline 205. The reservoir end cover 203, the end cover suction valve 204, the end cover suction pipeline 205, the second connecting piece 206 and the third connecting piece 207 jointly constitute an end cover assembly.

[0077] Specifically, the reservoir shell 201 and the lower surface of the floating piston 202 form the reservoir oil cavity 209, and the reservoir shell 201 and the upper surface of the floating piston 202 and the reservoir end cover 203 form the reservoir gas cavity 208. The floating piston 202 and the reservoir shell 201, and the reservoir end cover 203 and the reservoir shell 201 are respectively sealed by the sealing piece 210.

[0078] Before the reservoir 20 is connected with the oil side membrane cavity 111 of the diaphragm compressor, a certain pressure of high-pressure gas and hydraulic oil is stored through the end cover suction pipeline 205 and the oil passage 211 respectively. The reservoir oil cavity 209 is connected with the oil side membrane cavity 111 of the diaphragm compressor through the control valve, Figure 3The diagram shows the state of the control valve closed and the diaphragm compressor at the end of the suction phase, at which time the diaphragm 105 is in the equilibrium position.

[0079] The oil pressure in the diaphragm compressor decreases synchronously with the gas pressure during the expansion of the gas, and the diaphragm compressor overflows oil during the exhaust phase and replenishes oil during the suction phase. In the absence of hydraulic oil leakage, the amount of replenished oil is equal to the amount of overflown oil.

[0080] When the control valve connecting the oil-side membrane chamber 111 of the diaphragm compressor and the oil chamber 209 of the reservoir is opened, the high-pressure gas in the gas chamber 208 of the reservoir pushes the floating piston 202 downward, causing the volume of hydraulic oil in the oil chamber 209 of the reservoir, Δv oil , to flow into the oil-side membrane chamber 111 of the diaphragm compressor through the connecting pipeline during the expansion and suction phases of the diaphragm compressor. Taking into account the compressibility of the hydraulic oil, the volume of the hydraulic oil in the oil-side membrane chamber 111 of the diaphragm compressor increases by Δv oil-e after expansion.

[0081] As shown in Figure 4 , the total increase in the volume of the hydraulic oil in the oil-side membrane chamber 111 of the diaphragm compressor is Δv oil + Δv oil-e , causing the diaphragm 105 to deform upward at the end of the suction phase, resulting in a decrease in the volume of the gas-side membrane chamber 110 and a decrease in the suction volume. During the compression phase of the diaphragm compressor, the hydraulic oil pressure in the oil-side membrane chamber 111 of the diaphragm compressor increases synchronously with the gas pressure, and the hydraulic oil that flowed into the oil-side membrane chamber 111 of the diaphragm compressor during the expansion phase flows into the oil chamber 209 of the reservoir through the connecting pipeline. Thus, the diaphragm compressor can reduce the total flow by Δq v during the working cycle.

[0082] Before the flow of the diaphragm compressor is adjusted, several reservoirs 20 with different volumes can be connected in parallel. The different volumes of these reservoirs 20 are designed to meet various flow requirements for flexible adjustment. As shown in Figure 5 , three reservoirs 20 are connected in parallel.

[0083] As shown in Figure 5 , the embodiment of the present application also includes a control system 30, which includes a PLC control module 301, an oil pressure sensor 302, and a flow meter 303. The flow meter 303 is connected to the exhaust pipeline of the diaphragm compressor; the oil pressure sensor 302 is connected to the oil-side membrane chamber 111 of the diaphragm compressor; and the PLC control module 301 is connected to the control valve of the reservoir 20, the oil pressure sensor 302, and the flow meter 303.

[0084] Specifically, the control valve of the liquid accumulator is controlled by the PLC control module 301. The diaphragm compressor is provided with an oil pressure sensor 302 and a flow meter 303. The signals of the flow meter 303 and the oil pressure sensor 302 are transmitted to the PLC control module 301. The PLC control module 301 receives the signals of the oil pressure sensor 302 and the flow meter 303, analyzes the oil overflow pressure and the oil pressure at the end of the suction through data processing. The PLC control module 301 selects to open the switches of a plurality of parallel liquid accumulators according to the target flow.

[0085] The diaphragm compressor flow regulating method of the present application will be further described below through specific embodiments.

[0086] Please refer to Figures 2 to 5 , a diaphragm compressor flow regulating method applied to a diaphragm compressor, wherein the diaphragm compressor comprises a membrane head structure 10, and the membrane head structure 10 has an oil side membrane cavity 111. The structure of the membrane head structure 10 is shown in Figure 1 . The diaphragm compressor flow regulating method comprises the following steps:

[0087] Step 1: connecting the oil side membrane cavity 111 with a plurality of liquid accumulator oil cavities 209 through pipelines respectively; each of the liquid accumulators 20 has a liquid accumulator oil cavity 209, and the outlet of each of the liquid accumulator oil cavities 209 is provided with a control valve.

[0088] In the embodiment of the present application, the number of the liquid accumulators 20 is at least one, and the specific number of the liquid accumulators 20 can be selected according to actual needs. When the number of the liquid accumulators 20 is ≥2, a plurality of liquid accumulators 20 are connected in parallel. In the embodiment of the present application, a plurality of liquid accumulators 20 with different volumes can be connected in parallel before regulating the flow of the diaphragm compressor. The different volumes of the liquid accumulators 20 are designed to meet the needs of various flow regulation. The structure of the liquid accumulator 20 is shown in Figure 2 .

[0089] Step 2: obtaining the volume of the hydraulic oil in each of the liquid accumulator oil cavities 209 entering the oil side membrane cavity 111 and the volume of the hydraulic oil in the oil side membrane cavity 111 expanding at the end of the suction of the diaphragm compressor, so as to calculate the controllable flow of each of the liquid accumulators 20 in the working cycle of the diaphragm compressor.

[0090] The controllable flow of the liquid accumulators 20 with different volumes can be calculated in turn according to the method of step 2. The calculation formula of the controllable flow of each of the liquid accumulators 20 in the working cycle of the diaphragm compressor is as follows:

[0091] Δq v =(Δv oil +Δv oil-e )λ T λ p λv-e n;

[0092] wherein, Δq v represents the controllable flow of one reservoir of the diaphragm compressor in a working cycle; Δv oil represents the volume of hydraulic oil in one reservoir oil chamber of the diaphragm compressor entering the oil side membrane chamber at the end of suction; Δv oil-e represents the volume of hydraulic oil in the oil side membrane chamber of the diaphragm compressor expanding at the end of suction; λ T represents the temperature coefficient caused by the intake heating of the diaphragm compressor; λ p is the pressure coefficient caused by the resistance loss of the diaphragm compressor; λ v-e is the gas expansion coefficient caused by the clearance volume of the diaphragm compressor; n represents the speed of the diaphragm compressor.

[0093] Each of the reservoirs 20 has a reservoir gas chamber 208; the method for obtaining the volume of hydraulic oil in one reservoir oil chamber 209 of the diaphragm compressor entering the oil side membrane chamber 111 at the end of suction is as follows:

[0094] The volume of the reservoir gas chamber, the oil overflow pressure of the diaphragm compressor, and the oil pressure at the end of suction of the diaphragm compressor are obtained to calculate the volume of hydraulic oil in one reservoir oil chamber 209 of the diaphragm compressor entering the oil side membrane chamber 111 at the end of suction, denoted as Δv oil . The calculation formula of Δv oil is as follows:

[0095]

[0096] wherein, Δv oil represents the volume of hydraulic oil in one reservoir oil chamber of the diaphragm compressor entering the oil side membrane chamber at the end of suction; v o represents the volume of the reservoir gas chamber; p0 represents the oil overflow pressure of the diaphragm compressor; p1 represents the oil pressure at the end of suction of the diaphragm compressor; m represents the process index.

[0097] The method for obtaining the volume of hydraulic oil in the oil side membrane chamber 111 of the diaphragm compressor expanding at the end of suction is as follows:

[0098] The oil overflow pressure of the diaphragm compressor, the oil pressure at the end of suction of the diaphragm compressor, and the total volume of all hydraulic oil in the oil side membrane chamber and the reservoir oil chamber communicating with the oil side membrane chamber of the diaphragm compressor at the end of exhaust are obtained to calculate the volume of hydraulic oil in the oil side membrane chamber 111 of the diaphragm compressor expanding at the end of suction, denoted as Δv oil-e . The calculation formula of Δv oil-e is as follows:

[0099] wherein, Δv oil-erepresents the volume of hydraulic oil expansion in the oil-side diaphragm chamber at the end of the suction of the diaphragm compressor; p0represents the oil overflow pressure of the diaphragm compressor; p1represents the oil pressure at the end of the suction of the diaphragm compressor; β represents the bulk modulus of the hydraulic oil; v oil-tdc represents the total volume of all hydraulic oils in the oil-side diaphragm chamber and the oil reservoir chamber communicated with the oil-side diaphragm chamber at the end of the discharge of the diaphragm compressor.

[0100] Step 3, obtaining the required regulated flow of the diaphragm compressor.

[0101] The embodiment of the present application calculates the required regulated flow of the diaphragm compressor according to the target flow of the diaphragm compressor and the actual flow of the diaphragm compressor. Specifically, the required regulated flow of the diaphragm compressor is obtained by using the difference between the target flow of the diaphragm compressor and the actual flow of the diaphragm compressor. The actual flow of the diaphragm compressor is obtained by reading the flow meter 303 connected to the discharge pipeline of the diaphragm compressor.

[0102] Step 4, comparing the required regulated flow of the diaphragm compressor with the available regulated flow of each oil reservoir 20 in the working cycle of the diaphragm compressor, and opening the control valve of the oil reservoir 20 matched with the required regulated flow of the diaphragm compressor.

[0103] Step 5, after the diaphragm compressor is adjusted to work stably in step 4, obtaining the actual flow of the diaphragm compressor; when the actual flow of the diaphragm compressor meets the following condition, the adjustment program is terminated:

[0104] (1-λ)q g ≤q≤(1+λ)q g ; wherein λ is a regulated margin factor, q g is the target flow of the diaphragm compressor, and q is the actual flow of the compressor.

[0105] Step 6, after the diaphragm compressor is adjusted to work stably in step 4, obtaining the actual flow of the diaphragm compressor; when the actual flow of the diaphragm compressor does not meet the condition (1-λ)q g ≤q≤(1+λ)q g , the following steps are performed:

[0106] When q<(1-λ)q g , the control valve of the oil reservoir 20 matched with the required regulated flow of the diaphragm compressor is closed, and the control valve of the oil reservoir 20 matched with the next closest required regulated flow of the diaphragm compressor is opened; step 5 is performed until the actual flow of the diaphragm compressor meets the condition (1-λ)q g ≤q≤(1+λ)q g , and the adjustment program is terminated.

[0107] Step 7, when q>(1+λ)qg When the actual flow of the diaphragm compressor meets (1-λ)q g ≤q≤(1+λ)q g After the condition is met, the adjustment procedure is terminated.

[0108] In the embodiment of the present application, the liquid reservoirs 20 of different capacities are sorted according to the size of the flow that can be regulated, and the liquid reservoir 20 that is next to the liquid reservoir 20 of the required regulated flow of the diaphragm compressor is the liquid reservoir 20 that is next to the liquid reservoir 20 of the required regulated flow of the diaphragm compressor.

[0109] In summary, the embodiment of the present application increases the number of liquid reservoirs of different capacities in parallel to achieve stepless regulation of the flow of the diaphragm compressor, and the energy loss is small during flow regulation, which does not affect the stability of the system and does not have a negative impact on the service life of the compressor, and has a simple structure, convenient installation and low cost, and can exhibit good performance and high operability during the flow regulation process.

[0110] The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for regulating the flow rate of a diaphragm compressor, applied to a diaphragm compressor, the diaphragm compressor comprising a membrane head structure, the membrane head structure having an oil-side membrane cavity; characterized in that, Includes the following steps: The oil-side membrane cavity is connected to multiple liquid reservoirs via pipelines; each liquid reservoir has an oil reservoir chamber, and each oil reservoir chamber outlet is equipped with a control valve; The volume of hydraulic oil entering the oil-side diaphragm chamber from each reservoir at the end of the diaphragm compressor intake and the volume of hydraulic oil expanding in the oil-side diaphragm chamber are obtained in order to calculate the adjustable flow rate of each reservoir in the working cycle of the diaphragm compressor. Obtain the required regulated flow rate for the diaphragm compressor; The required regulated flow rate of the diaphragm compressor is compared with the regulated flow rate of each reservoir in the working cycle of the diaphragm compressor, and the control valve of the reservoir that matches the required regulated flow rate of the diaphragm compressor is opened. After the diaphragm compressor has been adjusted to operate stably, the actual flow rate of the diaphragm compressor is obtained; The regulation program terminates when the actual flow rate of the diaphragm compressor meets the following conditions: (1-λ)q g ≤q≤(1+λ)q g Where λ is the control margin factor, and q g q represents the target flow rate of the diaphragm compressor, and q represents the actual flow rate of the diaphragm compressor.

2. The diaphragm compressor flow regulation method according to claim 1, characterized in that, 0.1 < λ < 0.

15.

3. The diaphragm compressor flow regulation method according to claim 1, characterized in that, When the actual flow rate of the diaphragm compressor does not satisfy (1-λ)q g ≤q≤(1+λ)q g If the conditions are met, the following steps will be performed: When q < (1-λ)q g At the same time, close the control valve of the reservoir that matches the required flow rate of the diaphragm compressor, and open the control valve of the reservoir that is close to the required flow rate of the diaphragm compressor. After the diaphragm compressor has stabilized, return to the step of obtaining the actual flow rate of the diaphragm compressor, until the actual flow rate of the diaphragm compressor satisfies (1-λ)q. g ≤q≤(1+λ)q g Once the conditions are met, the adjustment procedure terminates.

4. The diaphragm compressor flow regulation method according to claim 1, characterized in that, When the actual flow rate of the diaphragm compressor does not satisfy (1-λ)q g ≤q≤(1+λ)q g If the conditions are met, the following steps will be performed: When q>(1+λ)q g Then, return to the step of calculating the required controlled flow rate of the diaphragm compressor. At the same time, compare the calculated required controlled flow rate of the diaphragm compressor with the controllable flow rate of each reservoir of the diaphragm compressor in the working cycle, until the actual flow rate of the diaphragm compressor meets (1-λ)q. g ≤q≤(1+λ)q g Once the conditions are met, open the control valve of the reservoir that matches the required flow rate of the diaphragm compressor, and the adjustment program will terminate.

5. The diaphragm compressor flow regulation method according to claim 1, characterized in that, The formula for calculating the adjustable flow rate of each reservoir in the working cycle of a diaphragm compressor is as follows: Δq v =(Δv oil +Δv oil-e )l T l p l v-e n; Where, Δq v This indicates the adjustable flow rate of a reservoir in the diaphragm compressor during its operating cycle; Δv oil Δv represents the volume of hydraulic oil that enters the oil-side diaphragm chamber from a reservoir oil chamber at the end of the diaphragm compressor's intake phase; oil-e λ represents the volume of hydraulic oil that expands in the oil-side diaphragm chamber at the end of the diaphragm compressor's intake phase; T λ represents the temperature coefficient resulting from intake air heating in a diaphragm compressor. p The pressure coefficient resulting from the resistance loss of the diaphragm compressor; λ v-e is the gas expansion coefficient caused by the clearance volume of the diaphragm compressor; n represents the rotational speed of the diaphragm compressor.

6. The diaphragm compressor flow regulation method according to claim 5, characterized in that, Each of the aforementioned reservoirs has a reservoir gas chamber; the method for obtaining the volume of hydraulic oil entering the oil-side diaphragm chamber from the oil chamber of one reservoir at the end of the diaphragm compressor's intake is as follows: The volume of the reservoir's gas chamber, the overflow pressure of the diaphragm compressor, and the oil pressure at the end of the diaphragm compressor's suction cycle are obtained to calculate the volume of hydraulic oil entering the oil-side diaphragm chamber from one reservoir's oil chamber at the end of the diaphragm compressor's suction cycle, denoted as Δv. oil ; Δv oil The calculation formula is as follows: Among them, v o p0 represents the volume of the gas chamber of the liquid reservoir; p1 represents the oil overflow pressure of the diaphragm compressor; p1 represents the oil pressure at the end of the suction cycle of the diaphragm compressor; m represents the process index.

7. The diaphragm compressor flow regulation method according to claim 5, characterized in that, The method for obtaining the volume of hydraulic oil expansion in the oil-side diaphragm chamber at the end of the diaphragm compressor's suction cycle is as follows: Obtain the overflow oil pressure of the diaphragm compressor, the oil pressure at the end of the diaphragm compressor's suction cycle, and the total volume of all hydraulic oil in the oil-side diaphragm chamber and the reservoir oil chamber connected to the oil-side diaphragm chamber at the end of the diaphragm compressor's discharge cycle. Calculate the volume of hydraulic oil expansion in the oil-side diaphragm chamber at the end of the diaphragm compressor's suction cycle, denoted as Δv. oil-e ; Δv oil-e The calculation formula is as follows: Where p0 represents the overflow oil pressure of the diaphragm compressor; p1 represents the oil pressure at the end of the suction cycle of the diaphragm compressor; β represents the bulk modulus of the hydraulic oil; v oil-tdc This indicates the total volume of all hydraulic oil in the oil-side diaphragm chamber and the reservoir oil chamber connected to the oil-side diaphragm chamber at the end of the diaphragm compressor's exhaust phase.

8. The diaphragm compressor flow regulation method according to claim 1, characterized in that, The liquid reservoir includes a liquid reservoir housing, a floating piston, and a liquid reservoir end cap; the liquid reservoir end cap is fixedly connected to the liquid reservoir housing and is used to seal the liquid reservoir housing; the floating piston is slidably disposed inside the liquid reservoir housing so that the internal spaces of the liquid reservoir housing and the liquid reservoir end cap are separated to form a liquid reservoir oil chamber and a liquid reservoir gas chamber.

9. The diaphragm compressor flow regulation method according to claim 8, characterized in that, The reservoir oil chamber has an oil circuit, and the reservoir control valve is configured on the corresponding oil circuit; the reservoir air chamber is configured with an end cap suction pipe, and the end cap suction pipe is configured with an end cap suction valve.

10. The diaphragm compressor flow regulation method according to claim 1, characterized in that, The diaphragm compressor also includes a control system, which includes a PLC control module, an oil pressure sensor, and a flow meter; the flow meter is connected to the exhaust pipe of the diaphragm compressor; the oil pressure sensor is connected to the oil-side diaphragm chamber of the diaphragm compressor; and the PLC control module is connected to the control valve signals of the oil pressure sensor, the flow meter, and the liquid reservoir, respectively.

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