System and method for adjusting flow of diaphragm compressor and reducing gas content of hydraulic oil

Abstract

The invention relates to a method and a system for adjusting the flow of a diaphragm compressor and reducing the gas content of hydraulic oil, in particular to a system and a method for adjusting the flow of the diaphragm compressor and reducing the gas content of the hydraulic oil. The opening degree of the electric proportional valve is controlled in real time, so that the air inlet pressure of a high-pressure air cavity I of the flow regulator is regulated and controlled, and the volume of hydraulic oil, flowing into an oil side diaphragm cavity of the diaphragm compressor, in an oil cavity III in the flow regulator in the expansion and air suction stages of the compressor is controlled; and in the compression and exhaust stages, the exhaust pressure of the high-pressure air cavity is set through the electric proportional valve, hydraulic oil entering the oil side diaphragm cavity of the diaphragm compressor flows into the oil cavity III again, and the whole flow adjusting process is completed. Meanwhile, by means of the ingenious design of the device and the non-return performance of the one-way valve, the gas content of the hydraulic oil can be reduced while the flow is adjusted.

Description

Technical Field

[0001] The invention belongs to the technical field of diaphragm machines, and in particular relates to a system and method for regulating the flow of a diaphragm compressor and reducing the gas content of hydraulic oil. Background Art

[0002] Hydrogen refueling stations play a vital role in the application of hydrogen energy. They can provide hydrogen efficiently and cleanly, support the rapid filling of hydrogen fuel cell vehicles, promote the widespread application of renewable energy and contribute to environmental protection.

[0003] The diaphragm compressor has efficient and stable hydrogen compression capabilities, can work under high pressure and avoid leakage. Its oil-free design ensures the purity of hydrogen, avoiding oil pollution and related safety risks. Through the diaphragm structure, it provides good sealing and reduces the risk of hydrogen leakage. At the same time, its compression process is efficient and energy-saving, adapting to the high permeability of hydrogen, and is widely used in hydrogen refueling stations, chemical and medical gas fields. Its simple structure, strong shock resistance, and easy maintenance can provide reliable support for the safe storage and transportation of high-purity gas. Therefore, diaphragm compressors are widely used in hydrogen refueling stations due to their high efficiency, safety and durability to ensure the stability of hydrogen supply.

[0004] However, hydrogen refueling stations are typical variable working conditions. Under variable working conditions, the unloading of hydrogen from the long tube trailer requires a two-stage diaphragm compressor to complete. The first-stage pressure ratio of the two-stage diaphragm compressor is only related to the structural parameters of the first and second-stage compressors. As the pressure of the hydrogen in the trailer decreases, the pressure in the hydrogen storage tank of the hydrogen refueling station increases, and the second-stage pressure ratio changes significantly, resulting in unreasonable pressure ratio distribution of the entire diaphragm compressor system, causing energy waste, which is not conducive to the efficient and stable operation of the compressor. Although by adjusting the flow of a certain stage of the diaphragm compressor, the first-stage pressure ratio and the second-stage pressure ratio can be redistributed for the stable operation of the compressor. However, as the hydraulic oil in the diaphragm compressor flows from the overflow valve to the middle body and then flows into the oil tank through the crankcase, the hydraulic oil will inevitably come into contact with the air in the box and the middle body, resulting in a certain amount of gas in the hydraulic oil. When the hydraulic oil contains gas, the bubbles will expand or compress with the change of the hydraulic oil pressure, or even rupture, causing system pressure fluctuations or vibrations, thereby aggravating the wear of the diaphragm, and may even cause cracks, ruptures or fatigue damage. This will affect the stability and safety of the equipment.

[0005] In order to improve the stability and safety of the equipment, the flow of the diaphragm compressor is currently mainly regulated by variable speed regulation and bypass regulation, and the dissolved gas in the hydraulic oil is removed by heating degassing and vacuum degassing. However, the disadvantage of variable speed regulation in the flow regulation of the diaphragm compressor is that its adjustable range is narrow. Usually, the minimum frequency of the frequency conversion is 30Hz, which means that the flow regulation can only be performed between 60% and 100%. At the same time, when the compressor is running at a low speed, the lubrication of the driven components may be insufficient, resulting in increased wear of the components, thereby shortening the service life of the compressor. Bypass regulation will cause part of the compressed gas generated by the compressor to be not fully utilized, but bypassed and directly returned to the intake end. In this way, part of the energy of the compressor cannot be effectively utilized, the overall system efficiency is reduced, and the overall energy consumption is increased. At the same time, in the bypass regulation, the bypass gas directly returns to the compressor inlet, which may cause the intake temperature to rise and have an adverse effect on the performance of the compressor. The disadvantage of the heating degassing method for removing dissolved gas in the hydraulic oil is that the diaphragm compressor should strictly comply with the safety requirements of the hydrogenation station when working at the hydrogenation station. High temperature cannot be used to heat the hydraulic oil in the oil cavity to remove the dissolved gas in the hydraulic oil. The disadvantage of vacuum degassing is that it requires the purchase of a high-performance vacuum pump, which results in a high investment in equipment and requires regular maintenance, which increases the cost of use. At the same time, it consumes a lot of energy when operating the vacuum system, especially when handling a large amount of oil, which results in high energy consumption and increased operating costs.

[0006] Therefore, under the premise of reducing energy consumption, it is very necessary to design a system and method to ensure that the diaphragm compressor can maintain a stable, efficient and safe operating state under the variable operating conditions of the hydrogen refueling station. Summary of the invention

[0007] In view of the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a system and method for regulating the flow of a diaphragm compressor and reducing the gas content of hydraulic oil, thereby realizing stepless regulation of the flow of the diaphragm compressor and removing bubbles dissolved in the hydraulic oil by vacuum degassing, thereby ensuring the safe and stable operation of the diaphragm compressor.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] The present invention provides a system for regulating the flow of a diaphragm compressor and reducing the gas content of hydraulic oil, comprising:

[0010] A flow regulator, comprising a double-acting piston assembly and an air chamber housing and an oil chamber housing arranged from top to bottom, wherein the double-acting piston assembly has two piston parts, which are arranged in the air chamber housing and the oil chamber housing respectively, and can separate the air chamber housing from top to bottom into a high-pressure air chamber I and a low-pressure air chamber II, and also separate the oil chamber housing from top to bottom into an oil chamber III and a chamber IV, wherein the high-pressure air chamber I is provided with an exhaust valve and a first intake valve for adjusting the pressure of the high-pressure air chamber I, wherein the exhaust valve and the first intake valve are both connected to an air supply unit through an electrical proportional valve, wherein the oil chamber III is connected to an oil-side membrane chamber of a diaphragm compressor through a pipeline, wherein a control valve is arranged on the pipeline, wherein an intake pipe and an exhaust pipe are connected to the chamber IV, wherein both the exhaust pipe and the intake pipe are provided with a one-way valve, and the intake pipe is connected to a crankcase of the diaphragm compressor;

[0011] Flow sensor, used to measure the flow rate of the external exhaust pipeline of the diaphragm compressor;

[0012] An oil pressure sensor is connected to the oil-side diaphragm cavity of the diaphragm compressor and is used to monitor the pressure of the oil-side diaphragm cavity of the diaphragm compressor under working conditions;

[0013] The control unit is connected to the flow sensor, the oil pressure sensor and the two electrical proportional valves. The control unit is used to adjust the opening of the two electrical proportional valves according to the detection results of the flow sensor and the oil pressure sensor.

[0014] Preferably, the low-pressure air cavity II is also provided with a second air intake valve connected to the low-pressure air cavity II.

[0015] Preferably, before the flow regulator is connected to the diaphragm compressor, the height between the top surface of the piston portion located in the chamber IV and the oil chamber housing is 1 mm to 3 mm.

[0016] Preferably, the double-acting piston assembly includes a piston rod, the piston part arranged in the air chamber housing is an air chamber piston, and the piston part arranged in the oil chamber housing is an oil chamber piston. The piston rod vertically penetrates the air chamber housing and the oil chamber housing respectively, and is connected to the air chamber piston and the oil chamber piston respectively. The piston rod and the air chamber housing, as well as the piston rod and the oil chamber housing, are both sealed by a first seal, and the oil chamber piston and the oil chamber housing, as well as the air chamber piston and the air chamber housing, are both sealed by a second seal.

[0017] Preferably, the piston rod is provided with scale lines.

[0018] The method for regulating the flow of a diaphragm compressor and reducing the gas content of hydraulic oil comprises the following steps:

[0019] Before connecting the flow regulator to the diaphragm compressor system, it is necessary to store gas and hydraulic oil in the high-pressure gas chamber Ⅰ, low-pressure gas chamber Ⅱ and oil chamber Ⅲ of the flow regulator;

[0020] Then open the control valve to put the entire system into working condition;

[0021] When the diaphragm compressor is in the expansion and suction state, the control unit obtains the flow rate that needs to be regulated according to the flow measurement value and the flow setting value, and then the control unit processes and analyzes the obtained oil pressure measurement value to obtain the hydraulic oil pressure of the diaphragm compressor at the end of suction in the working state. The control unit adjusts the suction pressure of the high-pressure air chamber I by adjusting the opening of the electric proportional valve, and then adjusts the air pressure of the low-pressure air chamber II at the end of suction. The piston part located in the air chamber housing moves downward under the action of the high-pressure gas in the high-pressure air chamber I, thereby controlling the volume of the hydraulic oil in the oil chamber III entering the oil side membrane chamber of the diaphragm compressor and increasing the volume of the chamber IV and reducing the pressure, so as to realize the regulation of the flow of the diaphragm compressor and make the gas in the crankcase flow into the chamber IV with a sudden pressure drop through the one-way valve, so as to evacuate the crankcase;

[0022] When the diaphragm compressor is in the compression and exhaust stage, the hydraulic oil pressure in the diaphragm compressor continues to increase, pushing the piston part located in the oil chamber housing to move upward, causing the gas pressure in the high-pressure gas chamber I to continue to rise. When the gas pressure in the high-pressure gas chamber I reaches the exhaust pressure set by the electrical proportional valve, it is discharged through the exhaust valve. At the same time, the hydraulic oil in the oil side membrane chamber of the diaphragm compressor sent into the oil chamber III is returned to the oil chamber III in equal volume, and the volume of chamber IV becomes smaller, so that the gas pressure in chamber IV is discharged when it rises to a level greater than the atmospheric pressure.

[0023] Preferably, the algorithm for precise control of the flow rate of the diaphragm compressor in the control unit is:

[0024] Obtain the relationship between the adjustable flow rate of the diaphragm compressor and the volume change of the oil chamber III in the working cycle:

[0025] Δq v =Δv oil λ T λ p λ v-e n;

[0026] where Δv oil is the volume of hydraulic oil in oil chamber III entering the oil side diaphragm chamber at the end of suction of the diaphragm compressor; n is the speed of the diaphragm compressor; λ T is the temperature coefficient, λ p is the pressure coefficient, λ v-e is the expansion coefficient of the high pressure gas inside the clearance volume, Δq v It is the flow rate that can be controlled by the diaphragm compressor during the working cycle;

[0027] Obtain the relationship between the volume change of oil chamber III and the gas pressure in low-pressure gas chamber II:

[0028]

[0029] where v o is the design volume of low-pressure air chamber II in the initial state, p 1 is the pressure of the gas in the low-pressure chamber II at the end of suction of the diaphragm compressor, p 0 is the design gas pressure in the low-pressure gas chamber II under the initial condition, and m is the process index;

[0030] Obtain the relationship between the gas pressure in the low-pressure air chamber II at the end of the diaphragm compressor suction, the suction pressure of the high-pressure air chamber I, and the pressure of the hydraulic oil at the end of the suction:

[0031]

[0032] where p in is the suction pressure of high pressure air chamber Ⅰ, p oil is the pressure of the hydraulic oil in the oil chamber III at the end of suction, S gas is the area of ​​the upper surface of the air chamber piston, S oil is the area of ​​the lower surface of the oil chamber piston, m is the mass of the double-acting piston system, g is the acceleration of gravity, and p 1 It is the pressure of the gas in the low-pressure chamber II at the end of suction of the diaphragm compressor.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention utilizes the law of coordinated changes in oil and gas pressure of diaphragm compressors and the unique oil replenishment and oil overflow mechanism of diaphragm compressors to design a system for regulating the flow rate of diaphragm compressors and reducing the gas content of hydraulic oil. The control unit measures and controls the actual flow rate of the diaphragm compressor's external exhaust pipeline and the oil pressure in the diaphragm compressor cylinder in real time, and then controls the opening of the electric proportional valve in real time to achieve regulation of the intake pressure of the high-pressure air chamber I of the flow regulator, and then controls the volume of the hydraulic oil in the oil chamber III of the flow regulator's internal oil chamber to flow into the oil side membrane chamber of the diaphragm compressor during the expansion and suction stages of the compressor. In the compression and exhaust stages, the exhaust pressure of the high-pressure air chamber has been set by the electric proportional valve, and the hydraulic oil entering the oil side membrane chamber of the diaphragm compressor flows back into the oil chamber III, completing the entire flow regulation process. At the same time, the ingenious design of the device and the non-return property of the one-way valve can reduce the gas content of the hydraulic oil while regulating the flow rate.

[0035] The patented device of the present invention has a simple structure and low manufacturing cost, and can show good performance and high operability in the process of flow regulation. It not only has good flow regulation function but also has the function of vacuuming and removing dissolved bubbles in hydraulic oil, and is a reliable multifunctional device. It will not affect the stability of the system during flow regulation, nor will it have a negative impact on the life of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1It is a schematic structural diagram of the flow regulator of the present invention.

[0037] Figure 2 This is a system diagram for regulating the flow rate of a diaphragm compressor and reducing the gas content of hydraulic oil according to the present invention.

[0038] Reference numerals

[0039] 01. Air cavity shell; 02. Air cavity piston; 03. Piston rod; 04. First suction valve; 05. Exhaust valve; 06. Air cavity end cover; 07. Oil cavity shell; 08. Oil cavity end cover; 09. Oil cavity piston; 1. Diaphragm compressor air side diaphragm head; 2. Diaphragm compressor exhaust valve; 3. Diaphragm compressor suction valve; 4. Air distribution plate; 5. Diaphragm; 6. Oil distribution plate; 7. Diaphragm compressor oil side diaphragm head; 8. Diaphragm compressor air side diaphragm cavity; 9. Diaphragm compressor oil side diaphragm cavity; 10. Electric proportional valve; 11. Check valve; 12. Flow sensor; 13. Oil pressure sensor; 14. Control valve, 1A. Second sealing member; 1B. First sealing member. DETAILED DESCRIPTION

[0040] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified.

[0041] The inventor discovered that the hydraulic oil pressure and the compressed gas pressure of the diaphragm compressor change in synergy during operation, that is, the oil pressure decreases synchronously with the gas pressure during the expansion of the gas, and increases synchronously with the gas pressure during the compression stage. In addition, the diaphragm compressor replenishes oil during the suction stage and overflows oil during the exhaust stage. At the same time, the unique geometric structure of the device design and the non-return property of the one-way valve are used to overflow the gas dissolved in the hydraulic oil by using the vacuum degassing method, which is a new multifunctional device.

[0042] In view of this, the present invention provides a system and method for regulating the flow of a diaphragm compressor and reducing the gas content of hydraulic oil, thereby realizing stepless regulation of the flow of the diaphragm compressor and removing bubbles dissolved in the hydraulic oil by a vacuum degassing method, thereby ensuring the safe and stable operation of the diaphragm compressor.

[0043] like Figure 1-2 As shown, the system for regulating the flow of a diaphragm compressor and reducing the gas content of hydraulic oil provided by the present invention comprises:

[0044] The flow regulator includes a double-acting piston assembly and an air chamber housing 01 and an oil chamber housing 07 arranged from top to bottom. The double-acting piston assembly has two piston parts, and the two piston parts are respectively arranged in the air chamber housing 01 and the oil chamber housing 07, so that the air chamber housing 01 can be separated from top to bottom into a high-pressure air chamber I and a low-pressure air chamber II, and the oil chamber housing 07 can also be separated from top to bottom into an oil chamber III and a chamber IV. The high-pressure air chamber I is provided with an exhaust valve 05 and a first intake valve 04 for adjusting the pressure of the high-pressure air chamber I. The exhaust valve 05 and the first intake valve 04 are both connected to the air supply unit through an electrical proportional valve 10. The oil chamber III is connected to the oil-side membrane chamber 9 of the diaphragm compressor through a pipeline, and a control valve 14 is provided on the pipeline. The chamber IV is connected with an intake pipe and an exhaust pipe, and a one-way valve 11 is provided on the exhaust pipe and the intake pipe, and the intake pipe is connected to the crankcase of the diaphragm compressor;

[0045] The flow sensor 12 is used to measure the flow rate of the external exhaust pipeline of the diaphragm compressor;

[0046] The oil pressure sensor 13 is connected to the oil-side membrane chamber 9 of the diaphragm compressor and is used to monitor the pressure of the oil-side membrane chamber 9 of the diaphragm compressor in the working state;

[0047] The control unit is connected to the flow sensor 12 , the oil pressure sensor 13 and the two electric proportional valves 10 , and is used to adjust the opening of the two electric proportional valves 10 according to the detection results of the flow sensor 12 and the oil pressure sensor 13 .

[0048] When the diaphragm compressor is in the expansion and suction state, the control unit receives the flow signal and oil pressure signal of the diaphragm compressor in the working state, and obtains the flow that needs to be regulated according to the flow setting value and the flow measurement value. Then the control system processes and analyzes the hydraulic oil pressure measurement value obtained to obtain the hydraulic oil pressure of the diaphragm compressor at the end of suction in the working state. The control unit adjusts the suction pressure of the high-pressure air chamber I by adjusting the opening of the electric proportional valve 10, and then adjusts the air pressure of the low-pressure air chamber II at the end of suction. The piston part located in the air chamber housing 01 moves downward under the action of the high-pressure gas in the high-pressure air chamber I, thereby controlling the volume of the hydraulic oil in the oil chamber III entering the oil side membrane chamber 9 of the diaphragm compressor and increasing the volume of the chamber IV and reducing the pressure, so as to realize the regulation of the flow of the diaphragm compressor while allowing the gas in the crankcase to flow into the chamber IV with a sudden pressure drop through the one-way valve 11, thereby evacuating the crankcase.

[0049] When the diaphragm compressor is in the compression and exhaust stages, the hydraulic oil pressure in the diaphragm compressor continues to increase, pushing the piston part located in the oil chamber housing 07 to move upward, causing the gas pressure in the high-pressure gas chamber I to continue to rise. When the gas pressure in the high-pressure gas chamber I reaches the exhaust pressure set by the electrical proportional valve 10, it is discharged through the exhaust valve 05. The hydraulic oil in the oil side membrane chamber 9 of the diaphragm compressor sent into the oil chamber III is returned to the oil chamber III in equal volume, and the volume of chamber IV becomes smaller, so that the gas pressure in chamber IV is discharged when it rises to a level greater than the atmospheric pressure.

[0050] The double-acting piston assembly moves downward under the action of the high-pressure gas in the high-pressure gas chamber I, thereby controlling the volume of the hydraulic oil in the oil chamber III entering the oil-side diaphragm chamber 9 of the diaphragm compressor and the volume of chamber IV, so as to achieve the regulation of the flow of the diaphragm compressor while allowing the gas in the crankcase to flow into the chamber IV where the pressure drops suddenly through the one-way valve 11.

[0051] The diaphragm compressor comprises a diaphragm compressor air side diaphragm head 1, a diaphragm compressor exhaust valve 2, a diaphragm compressor suction valve 3, an air distribution plate 4, a diaphragm 5, an oil distribution plate 6, a diaphragm compressor oil side diaphragm head 7, a diaphragm compressor air side diaphragm cavity 8 and a diaphragm compressor oil side diaphragm cavity 9.

[0052] like Figure 1 As shown, a specific structure of a flow regulator includes an air chamber housing 01, an air chamber piston 02, a double-acting piston rod with scale 03, a first air intake valve 04, an air exhaust valve 05, an air chamber end cover 06, an oil chamber housing 07, an oil chamber end cover 08, and an oil chamber piston 09. The air chamber housing and the air chamber end cover 06 together form the air chamber housing 01, wherein the air chamber housing and the upper end surface of the air chamber piston 02 form a high-pressure air chamber I, and the air chamber housing and the lower end surface of the air chamber piston 02 form a low-pressure air chamber II. The oil chamber housing and the oil chamber end cover 08 together form the oil chamber housing 07, wherein the oil chamber housing and the lower end surface of the oil chamber piston 09 form an oil chamber III, and the oil chamber housing and the upper end surface of the air chamber piston 02 form a chamber IV that can be used for vacuuming.

[0053] The double-acting piston assembly includes an oil chamber piston 09, an air chamber piston 02 and a piston rod 03. The oil chamber piston 09 and the oil chamber housing 07, and the air chamber piston 02 and the air chamber housing 01 are sealed by a second seal 1A. The piston rod 03 and the oil chamber end cover 08, and the piston rod 03 and the air chamber end cover 06 are sealed by a first seal 1B.

[0054] Specifically, the low-pressure air chamber II is also provided with a second air intake valve in communication with the low-pressure air chamber II. The purpose of providing the second air intake valve in communication with the low-pressure air chamber II is to store gas and hydraulic oil at a certain pressure in the high-pressure air chamber, the low-pressure air chamber and the oil chamber III respectively before the flow regulator is connected to the diaphragm compressor system.

[0055] Specifically, before the flow regulator is connected to the diaphragm compressor, the height between the top surface of the piston in chamber IV and the oil chamber housing 07 is 1 mm to 3 mm. In order to rapidly increase the volume of chamber IV during the operation of the flow regulator so that its internal pressure is close to vacuum, the crankcase and the middle body of the diaphragm compressor storing hydraulic oil are better evacuated, and the gas dissolved in the hydraulic oil is released by vacuum degassing, thereby reducing the gas content of the hydraulic oil in the diaphragm compressor.

[0056] Specifically, the piston rod 03 is provided with scale lines. According to the known thickness of the air cavity wall in the flow regulator and the change of the scale lines provided on the piston rod 03, the height of the chamber IV is limited to 1 mm to 3 mm.

[0057] The method for regulating the flow of a diaphragm compressor and reducing the gas content of hydraulic oil comprises the following steps:

[0058] Before the flow regulator is connected to the diaphragm compressor system, gas and hydraulic oil are stored in the high-pressure gas chamber I, the low-pressure gas chamber II and the oil chamber III respectively; then the control valve 14 is opened to put the entire system into working condition;

[0059] When the diaphragm compressor is in the expansion and suction state, the control unit obtains the flow rate that needs to be regulated according to the flow measurement value and the flow setting value, and then the control unit processes and analyzes the obtained oil pressure measurement value to obtain the hydraulic oil pressure of the diaphragm compressor at the end of suction in the working state. The control unit adjusts the suction pressure of the high-pressure air chamber I by adjusting the opening of the electric proportional valve 10, and then adjusts the air pressure of the low-pressure air chamber II at the end of suction. The piston part located in the air chamber housing 01 moves downward under the action of the high-pressure gas in the high-pressure air chamber I, thereby controlling the volume of the hydraulic oil in the oil chamber III entering the oil side membrane chamber 9 of the diaphragm compressor and increasing the volume of the chamber IV and reducing the pressure, so as to realize the regulation of the flow of the diaphragm compressor and make the gas in the crankcase flow into the chamber IV with a sudden pressure drop through the one-way valve 11, so as to evacuate the crankcase;

[0060] When the diaphragm compressor is in the compression and exhaust stage, the hydraulic oil pressure in the diaphragm compressor continues to increase, pushing the piston part located in the oil chamber housing 07 to move upward, causing the gas pressure in the high-pressure gas chamber I to continue to rise. When the gas pressure in the high-pressure gas chamber I reaches the exhaust pressure set by the electrical proportional valve 10, it is discharged through the exhaust valve 05. At the same time, an equal volume of hydraulic oil sent into the oil side membrane chamber 9 of the diaphragm compressor by the oil chamber III flows back to the oil chamber III, and the volume of chamber IV becomes smaller, so that the gas pressure in chamber IV is discharged when it rises to a level greater than the atmospheric pressure.

[0061] Specifically, the algorithm for precise flow control of the diaphragm compressor in the control unit is:

[0062] The algorithm for precise flow control of the diaphragm compressor in the control unit is:

[0063] Obtain the relationship between the adjustable flow rate of the diaphragm compressor and the volume change of the oil chamber III in the working cycle:

[0064] Δq v =Δv oil λ T λ p λ v-e n;

[0065] where Δv oil is the volume of hydraulic oil in oil chamber III entering the oil side diaphragm chamber at the end of suction of the diaphragm compressor; n is the speed of the diaphragm compressor; λ T is the temperature coefficient, λ p is the pressure coefficient, λ v-e is the expansion coefficient of the high pressure gas inside the clearance volume, Δq v It is the flow rate that can be controlled by the diaphragm compressor during the working cycle;

[0066] Obtain the relationship between the volume change of oil chamber III and the gas pressure in low-pressure gas chamber II:

[0067]

[0068] where v o is the design volume of low-pressure air chamber II in the initial state, p 1 is the pressure of the gas in the low-pressure chamber II at the end of suction of the diaphragm compressor, p 0 is the design gas pressure in the low-pressure gas chamber II under the initial condition, and m is the process index;

[0069] Obtain the relationship between the gas pressure in the low-pressure air chamber II at the end of the diaphragm compressor suction, the suction pressure of the high-pressure air chamber I, and the pressure of the hydraulic oil at the end of the suction:

[0070]

[0071] where p in is the suction pressure of high pressure air chamber Ⅰ, p oil is the pressure of the hydraulic oil in the oil chamber III at the end of suction, S gas is the area of ​​the upper surface of the air chamber piston, S oil is the area of ​​the lower surface of the oil chamber piston, m is the mass of the double-acting piston system, g is the acceleration of gravity, and p 1 It is the pressure of the gas in the low-pressure chamber II at the end of suction of the diaphragm compressor.

[0072] The control unit adjusts the opening of the electric proportional valve 10 so that the suction pressure p in Satisfies the value calculated by the above control unit.

[0073] Specifically, the diaphragm compressor does not consider the hydraulic oil leakage in both the gas suction stage and the exhaust stage.

[0074] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A system for regulating the flow of a diaphragm compressor and reducing the gas content of hydraulic oil, characterized in that: include: A flow regulator comprises a double-acting piston assembly and an air chamber housing (01) and an oil chamber housing (07) arranged from top to bottom. The double-acting piston assembly has two piston parts, which are arranged in the air chamber housing (01) and the oil chamber housing (07) respectively, so that the air chamber housing (01) can be separated from top to bottom into a high-pressure air chamber I and a low-pressure air chamber II, and the oil chamber housing (07) can also be separated from top to bottom into an oil chamber III and a chamber IV. The high-pressure air chamber I is provided with a An exhaust valve (05) and a first intake valve (04) of the high-pressure air chamber I pressure, the exhaust valve (05) and the first intake valve (04) are both connected to the air supply unit via an electrical proportional valve (10), the oil chamber III is connected to the oil-side membrane chamber (9) of the diaphragm compressor via a pipeline, a control valve (14) is provided on the pipeline, an intake pipe and an exhaust pipe are connected to the chamber IV, a check valve (11) is provided on the exhaust pipe and the intake pipe, and the intake pipe is connected to the crankcase of the diaphragm compressor; A flow sensor (12) for measuring the flow rate of an external exhaust pipeline of a diaphragm compressor; An oil pressure sensor (13) is connected to the oil-side diaphragm chamber (9) of the diaphragm compressor and is used to monitor the pressure of the oil-side diaphragm chamber (9) of the diaphragm compressor under working conditions; A control unit is connected to the flow sensor (12), the oil pressure sensor (13) and the two electrical proportional valves (10), and the control unit is used to adjust the opening of the two electrical proportional valves (10) according to the detection results of the flow sensor (12) and the oil pressure sensor (13).

2. The system for regulating flow of a diaphragm compressor and reducing the gas content of hydraulic oil according to claim 1, characterized in that: The low-pressure air cavity II is also provided with a second air intake valve which is in communication with the low-pressure air cavity II.

3. The system for regulating flow of a diaphragm compressor and reducing the gas content of hydraulic oil as claimed in claim 1, characterized in that: Before the flow regulator is connected to the diaphragm compressor, the height between the top surface of the piston portion located in the chamber IV and the oil chamber housing (07) is 1 mm to 3 mm.

4. The system for regulating flow of a diaphragm compressor and reducing the gas content of hydraulic oil as claimed in claim 1, characterized in that: The double-acting piston assembly comprises a piston rod (03), a piston portion arranged in an air chamber housing (01) being an air chamber piston (02), and a piston portion arranged in an oil chamber housing (07) being an oil chamber piston (09); the piston rod (03) vertically penetrates the air chamber housing (01) and the oil chamber housing (07), respectively, and is connected to the air chamber piston (02) and the oil chamber piston (09), respectively; the piston rod (03) and the air chamber housing (01) as well as the piston rod (03) and the oil chamber housing (07) are sealed by a first sealing member (1B); the oil chamber piston (09) and the oil chamber housing (07) as well as the air chamber piston (02) and the air chamber housing (01) are sealed by a second sealing member (1A).

5. The system for regulating flow of a diaphragm compressor and reducing the gas content of hydraulic oil as claimed in claim 4, characterized in that: The piston rod (03) is provided with scale lines.

6. The method for regulating the flow of a diaphragm compressor and reducing the gas content of hydraulic oil according to claim 1, characterized in that: The steps include: Before connecting the flow regulator to the diaphragm compressor system, it is necessary to store gas and hydraulic oil in the high-pressure gas chamber Ⅰ, low-pressure gas chamber Ⅱ and oil chamber Ⅲ of the flow regulator; Then, the control valve (14) is opened to put the entire system into working condition; When the diaphragm compressor is in the expansion and suction state, the control unit obtains the flow rate to be regulated according to the flow measurement value and the flow setting value, and then the control unit processes and analyzes the obtained oil pressure measurement value to obtain the hydraulic oil pressure of the diaphragm compressor at the end of suction in the working state. The control unit adjusts the suction pressure of the high-pressure air chamber I by adjusting the opening of the electric proportional valve (10), and then adjusts the air pressure of the low-pressure air chamber II at the end of suction. The piston part located in the air chamber housing (01) moves downward under the action of the high-pressure gas in the high-pressure air chamber I, thereby controlling the volume of the hydraulic oil in the oil chamber III entering the oil side membrane chamber (9) of the diaphragm compressor and increasing the volume of the chamber IV and reducing the pressure, so as to realize the regulation of the flow rate of the diaphragm compressor and at the same time make the gas in the crankcase flow into the chamber IV with a sudden pressure drop through the one-way valve (11), so as to evacuate the crankcase; When the diaphragm compressor is in the compression and exhaust stage, the hydraulic oil pressure in the diaphragm compressor continues to increase, pushing the piston part located in the oil chamber housing (07) to move upward, causing the gas pressure in the high-pressure gas chamber I to continue to rise. When the gas pressure in the high-pressure gas chamber I reaches the exhaust pressure set by the electrical proportional valve (10), it is discharged through the exhaust valve (05). At the same time, the hydraulic oil sent into the oil side membrane chamber (9) of the diaphragm compressor by the oil chamber III flows back to the oil chamber III, and the volume of chamber IV becomes smaller, so that the gas pressure in chamber IV is discharged when it rises to a level greater than the atmospheric pressure.

7. The method for regulating the flow of a diaphragm compressor and reducing the gas content of hydraulic oil according to claim 6, characterized in that: The algorithm for precise flow control of the diaphragm compressor in the control unit is: Obtain the relationship between the adjustable flow rate of the diaphragm compressor and the volume change of the oil chamber III in the working cycle: Δq v =Δv oil l T l p l v-e n; where Δv oil is the volume of hydraulic oil in oil chamber III entering the oil side diaphragm chamber at the end of suction of the diaphragm compressor; n is the rotation speed of the diaphragm compressor; λ T is the temperature coefficient, λ p is the pressure coefficient, λ v-e is the expansion coefficient of the high pressure gas inside the clearance volume, Δq v It is the flow rate that can be controlled by the diaphragm compressor during the working cycle; Obtain the relationship between the volume change of oil chamber III and the gas pressure in low-pressure gas chamber II: where v o is the design volume of low-pressure air chamber II under the initial state, p1 is the pressure of the gas in low-pressure air chamber II at the end of suction of the diaphragm compressor, p0 is the design gas pressure in low-pressure air chamber II under the initial state, and m is the process index; Obtain the relationship between the gas pressure in the low-pressure air chamber II at the end of the diaphragm compressor suction, the suction pressure of the high-pressure air chamber I, and the pressure of the hydraulic oil at the end of the suction: where p in is the suction pressure of high pressure air chamber Ⅰ, p oil is the pressure of the hydraulic oil in the oil chamber III at the end of suction, S gas is the area of ​​the upper surface of the air chamber piston, S oil is the area of ​​the lower surface of the oil chamber piston, m is the mass of the double-acting piston system, g is the acceleration of gravity, and p1 is the pressure of the gas in the low-pressure air chamber II at the end of the diaphragm compressor's suction.

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