Diaphragm compressor

Abstract

The invention discloses a diaphragm compressor, which belongs to the technical field of diaphragm compressors, and is characterized in that a second piston is additionally arranged on a piston assembly on the basis of the structure of the existing diaphragm compressor, the second piston is arranged on a piston rod, and the second piston axially reciprocates in a middle body. When the second piston moves rightwards, gas in the first cavity begins to expand, meanwhile, the middles of the diaphragms are vacuumized to enable the three diaphragms to be attached, the volume of the gas cavity is increased, the air suction amount is increased, and therefore the problem that the volume efficiency of the diaphragm compressor is poor due to diaphragm separation is solved. The oil pool of the crankcase is vacuumized, bubbles contained in oil in the oil pool of the crankcase are removed, the elasticity modulus of hydraulic oil is improved, the influence of gas contained in the hydraulic oil on the actual volume efficiency of the high-pressure diaphragm compressor is avoided, and the volume efficiency of the diaphragm compressor is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of diaphragm compressors, and particularly relates to a diaphragm compressor. Background Art

[0002] A diaphragm compressor is a positive displacement compressor. Different from a traditional reciprocating piston compressor that directly compresses gas through a piston, a diaphragm compressor drives a diaphragm to reciprocate by pushing hydraulic oil with a piston. Since the diaphragm divides the compression chamber into a gas chamber and an oil chamber, and the gas does not come into direct contact with the oil, it has advantages such as high purity and good sealing. In addition, due to its advantages of small vibration, low noise, small clearance volume, and stable operation, it is widely used in the work of hydrogen refueling stations.

[0003] The structure of the existing diaphragm compressor is as Figure 1 shown, including a diaphragm head assembly 01 (including a gas-side diaphragm head and an oil-side diaphragm head), a piston assembly 02, a crosshead assembly 03, a body assembly 04 (including a middle body and a crankcase), a crankshaft connecting rod assembly 05, and a plunger pump assembly 06. First, connect the gas-side diaphragm head and the oil-side diaphragm head into the diaphragm head assembly 01 through stud bolts; place a metal diaphragm between the gas-side diaphragm head and the oil-side diaphragm head and compress it with the pre-tightening force of the stud bolts; connect the middle body and the crankcase into the body assembly 04 through stud bolts, and then connect the diaphragm head assembly 01 and the body assembly 04 through threads; connect the crosshead assembly 03 with the piston assembly 02 and the crankshaft connecting rod assembly 05 through threads; place the crankshaft connecting rod assembly 05 in the crankcase; place the crosshead assembly 03 in the middle body; attach the plunger pump assembly 06 to the non-flywheel side of the crankshaft, extract hydraulic oil from the crankcase and supply it to the oil-side diaphragm head. The motor drives the crank connecting rod mechanism, which in turn drives the piston to reciprocate. When the piston moves upward to the top dead center, the piston pushes the hydraulic oil, further driving the diaphragm to deform upward. The diaphragm finally deforms and fits against the wall surface of the gas chamber, realizing the compression and exhaust of the gas in the gas chamber. When the piston moves downward, the oil pressure will decrease until it is lower than the intake pressure, and the intake pressure in the gas chamber will drive the diaphragm to deform into the oil chamber until the piston runs to the bottom dead center position.

[0004] For high-pressure exhaust working conditions, the exhaust pressure of the diaphragm compressor used in a hydrogen refueling station is usually 45 MPa or 90 MPa. At this time, the oil spill pressure will reach 60 MPa or 120 MPa, and the compressibility of the hydraulic oil cannot be ignored. This compressibility is largely caused by the presence of gas. If only simple treatment means such as oil return flowing along the wall surface and oil spill valve exhausting are adopted, the degassing efficiency is very low, and the decrease in volumetric efficiency is extremely severe under high-pressure conditions.

[0005] For the low-pressure intake condition, generally speaking, three metal diaphragms are selected for the diaphragm compressor. Grooves are opened on the middle diaphragm to connect the leak detection holes to the atmosphere. If the diaphragm on the gas side or oil side ruptures, the high-pressure gas or hydraulic oil will be discharged through the grooves to achieve the functions of safe production and early warning. During the negative-pressure intake process, the middle diaphragm is connected to the atmosphere. On both sides of the diaphragm on the gas side are negative pressure and atmospheric pressure respectively. The diaphragm on the gas side cannot return to the middle equilibrium position. The pressure in the oil chamber drops to the atmospheric pressure at the lowest, and the diaphragm on the oil side will normally return to the middle equilibrium position. Therefore, an air pocket will be generated between the three diaphragms, which indirectly reduces the gas chamber volume and significantly decreases the volumetric efficiency.

[0006] In the above diaphragm compressor, there is no effective device to remove the bubbles dissolved in the hydraulic oil. Currently, mainly an oil overflow valve is used to discharge the bubbles in the oil chamber before adjusting the oil pressure. However, this method is only applicable to discharging larger bubbles, and it cannot effectively discharge tiny bubbles and the bubbles dissolved in the oil, and cannot avoid the influence of gas-containing hydraulic oil on the actual volumetric efficiency of the high-pressure diaphragm compressor.

[0007] Compared with the normal-pressure intake, due to the diaphragm separation, the efficiency of the diaphragm compressor drops sharply under the negative-pressure intake. The above diaphragm compressor does not have a supporting device to improve the volumetric efficiency of the diaphragm compressor under the negative-pressure intake condition. In the prior art, the oil chamber pressure is adjusted by the oil filling amount to make the diaphragm rebound and reset. Its adjustment effect is not obvious and the diaphragm separation is not considered, and the negative impact brought by the diaphragm separation cannot be eliminated. Summary of the Invention

[0008] The present invention provides a diaphragm compressor, which effectively solves the technical problem that the volumetric efficiency of the existing diaphragm compressor decreases due to gas-containing hydraulic oil and diaphragm separation during the operation process, and at the same time provides a diaphragm compressor that effectively improves the overall volumetric efficiency.

[0009] The first object of the present invention is to provide a diaphragm compressor, which includes a diaphragm head assembly, a piston assembly, a crosshead assembly, and a body assembly arranged axially in sequence. The diaphragm head assembly includes a gas-side diaphragm head, an oil-side diaphragm head, and a diaphragm. The body assembly includes a middle body and a crankcase connected axially in sequence, and is characterized in that the piston assembly includes a piston rod, a first piston, and a second piston.

[0010] The first piston reciprocates axially in the oil-side diaphragm head. One end of the piston rod extends into the oil-side diaphragm head and abuts against the first piston, and the other end is connected to the crosshead assembly; the second piston is fixedly arranged on the piston rod, and the second piston reciprocates axially in the middle body.

[0011] The first piston reciprocates axially within the oil-side diaphragm head. One end of the piston rod extends into the oil-side diaphragm head and abuts against the first piston, while the other end is connected to the crosshead assembly. The second piston is fixedly arranged on the piston rod and reciprocates axially within the middle body.

[0012] The second piston divides the middle body into a first chamber close to the oil-side diaphragm head and a second chamber far from the oil-side diaphragm head. The diaphragm communicates with the first chamber, and the first chamber communicates with the crankcase. When the second piston moves towards the direction close to the crankcase, the gas in the diaphragm and the gas in the oil sump of the crankcase enter the first chamber, and the diaphragm adheres, removing the bubbles in the oil sump. When the second piston moves towards the direction close to the oil-side diaphragm head, the gas in the first chamber is discharged to the atmosphere.

[0013] As a preferred embodiment, a first through hole communicating with the first chamber is provided on the middle body, and a third through hole communicating with the diaphragm is provided on the oil-side diaphragm head. The third through hole and the first through hole are connected by a pipeline, and a first one-way valve is arranged along the direction from the third through hole to the first through hole.

[0014] As a preferred embodiment, a fourth through hole is provided on the crankcase, and the fourth through hole and the first through hole are connected by a pipeline. A second one-way valve is arranged along the direction from the fourth through hole to the first through hole.

[0015] As a preferred embodiment, a second through hole communicating with the first chamber is provided on the middle body, and a third one-way valve is arranged along the direction from the second through hole to the atmosphere.

[0016] As a preferred embodiment, an oil cylinder sleeve is arranged inside the diaphragm head assembly, and an oil cylinder hole is arranged inside the oil cylinder sleeve. The first piston can reciprocate axially within the oil cylinder hole. A first sealing ring is provided on the inner circumference of the oil cylinder hole close to the middle body, and one end of the piston rod extends into the first sealing ring and abuts against the first piston.

[0017] As a preferred embodiment, a second sealing ring is provided circumferentially at the contact end between the second piston and the middle body.

[0018] As a preferred embodiment, the stroke length of the second piston moving axially is less than the axial length of the first chamber.

[0019] As a preferred embodiment, a fifth through hole is further provided on the crankcase, and a safety valve is connected to the fifth through hole.

[0020] As a preferred embodiment, an oil through hole is provided inside the piston rod for lubricating the second piston.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] A diaphragm compressor provided by the present invention includes a diaphragm head assembly, a piston assembly, a crosshead assembly, and a body assembly arranged axially in sequence. The diaphragm head assembly includes a gas-side diaphragm head, an oil-side diaphragm head, and a diaphragm. The body assembly includes a middle body and a crankcase connected axially in sequence. Another piston is added to the existing piston assembly of the diaphragm compressor in the present invention. The piston assembly includes a piston rod, a first piston, and a second piston. The first piston reciprocates axially in the oil-side diaphragm head. One end of the piston rod extends into the oil-side diaphragm head and abuts against the first piston, and the other end is connected to the crosshead assembly. The second piston is fixedly arranged on the piston rod, and the second piston reciprocates axially in the middle body. The second piston divides the middle body into a first chamber close to the oil-side diaphragm head and a second chamber far from the oil-side diaphragm head. When the second piston moves towards the direction close to the crankcase, while the gas in the first chamber starts to expand, on the one hand, the middle of the diaphragm is evacuated, causing the three diaphragms to fit together, increasing the gas chamber volume and the suction volume, thus solving the problem of poor volumetric efficiency of the diaphragm compressor caused by diaphragm separation. On the other hand, the oil sump in the crankcase is evacuated, removing the bubbles in the oil in the oil sump of the crankcase, increasing the elastic modulus of the hydraulic oil, and avoiding the influence of gas-containing hydraulic oil on the actual volumetric efficiency of the high-pressure diaphragm compressor, effectively improving the volumetric efficiency of the diaphragm compressor. When the second piston moves towards the direction close to the oil-side diaphragm head, the gas in the first chamber starts to be compressed, and the compressed gas is discharged from the first chamber to the atmosphere. The present invention continuously evacuates and discharges the gas in the air bag between the three diaphragms and the inside of the crankcase as the diaphragm compressor operates, solving the problem of low actual volumetric efficiency under high pressure.

[0023] The diaphragm compressor provided by the present invention does not require an external vacuum pump and is directly attached to the existing diaphragm compressor mechanism, reducing the complexity of the equipment and can be opened and closed with the compressor, without additional operation. After the internal vacuum is stabilized, this system can stop evacuating when the safety valve is closed, reducing energy consumption; or it can also serve as a vacuum pump, improving economic benefits. Description of the Drawings

[0024] Figure 1 It is a schematic structural diagram of a diaphragm compressor in the prior art.

[0025] Figure 2 It is a schematic structural diagram of the diaphragm compressor of the present invention.

[0026] Figure 3 is Figure 2 a schematic structural diagram of the piston assembly in

[0027] Figure 4 is Figure 3 a three-dimensional structural diagram of the piston assembly in

[0028] Description of the reference numerals:

[0029] 01A, gas-side diaphragm head; 01B, oil-side diaphragm head; 13, diaphragm; 21, piston rod; 02A, first piston; 02B, second piston; 03, crosshead assembly; 04A, middle body; 04B, crankcase; 05, crankshaft connecting rod assembly; ⅠA, first chamber; ⅠB, second chamber; 07, first sealing ring; 08, second sealing ring; ⅡA, first through hole; ⅡB, second through hole; ⅢA, third through hole; ⅢB, fourth through hole; ⅢC, fifth through hole; 09, first check valve; 10, third check valve; 11, second check valve; 12, safety valve. Detailed implementation manners

[0030] In order to enable those skilled in the art to better understand and implement the technical solutions of the present invention, the following further describes the present invention in conjunction with specific embodiments and the attached Figures 1 to 4 drawings, but the specific embodiments cited are not intended to limit the present invention. In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0031] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the protection scope of the present invention. In the present invention, certain terms are used to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. The present invention does not distinguish components by the difference in nouns, but by the difference in the functions of the components. For example, the term "including" mentioned throughout the specification and claims is an open term, so it should be understood as "including but not limited to". The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features; in the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0032] Regarding what is mentioned in the background art of the present invention: A diaphragm compressor relies on the reciprocating motion of a diaphragm in a cylinder to compress and transport gas. The diaphragm is clamped by two limiting plates along the periphery to form a cylinder. Common diaphragm compressors use a metal diaphragm and are hydraulically driven to reciprocate in the cylinder, thereby achieving the compression and transportation of gas. Under high-pressure working conditions, the compression and expansion of the gas-containing hydraulic oil are the main factors affecting the volumetric efficiency. First, the existing oil spill valve exhaust device cannot effectively remove the tiny bubbles dissolved in the hydraulic oil, resulting in the actual volumetric efficiency being far lower than the design value. Second, during negative-pressure intake, the separation of the diaphragm will cause a decrease in the intake volume, thereby reducing the volumetric efficiency. Based on the above technical problems, the present invention provides a diaphragm compressor.

[0033] The technical content of the present invention will be described in detail below.

[0034] The present invention provides a diaphragm compressor, which includes a diaphragm head assembly, a piston assembly, a crosshead assembly 03, and a body assembly arranged axially in sequence. The diaphragm head assembly includes a gas-side diaphragm head 01A, an oil-side diaphragm head 01B, and a diaphragm 13. There are 3 diaphragms 13. The body assembly includes a middle body 04A and a crankcase 04B connected axially in sequence. The piston assembly includes a piston rod 21, a first piston 02A, and a second piston 02B. On the basis of the original piston rod 21 and the first piston 02A, the present invention newly sets a second piston 02B, thereby constructing a new piston assembly.

[0035] The first piston 02A reciprocates axially in the oil-side diaphragm head 01B. One end of the piston rod 21 extends into the oil-side diaphragm head 01B and abuts against the first piston 02A, and the other end is connected to the crosshead assembly 03. The second piston 02B is fixedly arranged on the piston rod 21 along the circumferential direction of the piston rod 21, and the second piston 02B reciprocates axially in the middle body 04A.

[0036] The second piston 02B divides the middle body 04A into a first chamber ⅠA close to the oil-side diaphragm head 01B and a second chamber ⅠB far from the oil-side diaphragm head 01B.

[0037] The diaphragm 13 communicates with the first chamber ⅠA, and discharges the gas in the diaphragm 13 into the first chamber ⅠA, ensuring that the diaphragm 13 is evacuated. The three diaphragms 13 are attached to each other, increasing the gas chamber volume and the intake volume, thereby solving the problem of poor volumetric efficiency of the diaphragm compressor caused by diaphragm separation.

[0038] The first chamber ⅠA communicates with the crankcase 04B, and discharges the gas contained in the oil in the oil sump of the crankcase 04B into the first chamber ⅠA, ensuring that the oil sump of the crankcase 04B is evacuated, thereby removing the bubbles contained in the oil in the oil sump and improving the volumetric efficiency of the diaphragm compressor.

[0039] To evacuate the diaphragm 13 and the crankcase 04B, the second piston 02B is moved towards the crankcase 04B, that is, the volume of the first chamber ⅠA becomes larger. At this time, on the one hand, the middle of the diaphragm 13 communicated with the first chamber ⅠA is evacuated, and the three diaphragms 13 are adhered together, thereby increasing the volume of the air chamber and the air intake volume, and solving the problem of poor volumetric efficiency of the diaphragm compressor caused by the separation of the diaphragms 13; on the other hand, the oil sump of the crankcase 04B communicated with the first chamber ⅠA is evacuated, removing the bubbles contained in the oil in the oil sump of the crankcase 04B, increasing the elastic modulus of the hydraulic oil, avoiding the influence of the gas-containing hydraulic oil on the actual volumetric efficiency of the high-pressure diaphragm compressor, and effectively improving the volumetric efficiency of the diaphragm compressor.

[0040] When the second piston 02B is moved towards the oil-side head 01B, the volume of the first chamber ⅠA becomes smaller, and the gas in the first chamber ⅠA needs to be discharged. At this time, it is ensured that the first chamber ⅠA is not communicated with the diaphragm 13 and the first chamber ⅠA is not communicated with the crankcase 04B, preventing the gas in the first chamber ⅠA from being discharged into the diaphragm 13 and the crankcase 04B, thereby having an adverse effect on the volumetric efficiency of the diaphragm compressor.

[0041] The technical effects of the present invention will be described below through specific embodiments.

[0042] Embodiment 1

[0043] A diaphragm compressor, as Figure 2 shown, includes a head assembly, a piston assembly, a crosshead assembly 3 and a body assembly arranged axially in sequence. The head assembly includes a gas-side head 01A, an oil-side head 01B and a diaphragm 13. There are 3 diaphragms 13. The body assembly includes a middle body 04A and a crankcase 04B connected axially in sequence. The piston assembly includes a piston rod 21, a first piston 02A and a second piston 02B.

[0044] The first piston 02A reciprocates axially in the oil-side head 01B. One end of the piston rod 21 extends into the oil-side head 01B and abuts against the first piston 02A, and the other end is connected to the crosshead assembly 03; the second piston 02B is arranged circumferentially along the piston rod 21 on the piston rod 21, as Figure 3 and Figure 4 shown, the second piston 02B reciprocates axially in the middle body 04A.

[0045] The second piston 02B divides the middle body 04A into a first chamber ⅠA close to the oil-side head 01B and a second chamber ⅠB far from the oil-side head 01B.

[0046] In the direction flowing along the diaphragm 13 towards the first chamber ⅠA, ensure the one-way connection between the diaphragm 13 and the first chamber ⅠA; in the direction flowing along the crankcase 04B towards the first chamber ⅠA, ensure the one-way connection between the first chamber ⅠA and the crankcase 04B. When the second piston 02B moves towards the direction close to the crankcase 04B, the middle of the diaphragm 13 is evacuated, the diaphragm 13 fits together, and the oil sump in the crankcase 04B is evacuated, removing the bubbles contained in the oil in the oil sump, thereby improving the volumetric efficiency of the diaphragm compressor.

[0047] It should be noted that for the diaphragm compressor provided by the present invention, the diaphragm head assembly, the fuselage main body, the crosshead assembly 03 and the crankshaft connecting rod assembly 05 arranged in sequence along the axial direction are all structures of the existing diaphragm compressor. Among them, the diaphragm head main body includes the gas-side diaphragm head 01A and the oil-side diaphragm head 01B. The gas-side diaphragm head 01A and the oil-side diaphragm head 01B are connected into the diaphragm head main body by stud bolts. The metal diaphragm is placed between the gas-side diaphragm head 01A and the oil-side diaphragm head 01B and is pressed by the pre-tightening force of the stud bolts; the fuselage assembly includes the middle body 04A and the crankcase 04B. The middle body 04A and the crankcase 04B are connected into the fuselage assembly by stud bolts. The diaphragm head assembly and the fuselage assembly are connected by threads; the crosshead assembly 03 is connected to the piston assembly and the crankshaft connecting rod assembly 05 by threads respectively. The crankshaft connecting rod assembly 05 is placed in the crankcase 04B; the crosshead assembly 03 is placed in the slideway of the middle body 04A; a piston pump assembly is additionally provided on the non-flywheel side of the crankshaft to extract hydraulic oil from the crankcase 04B and supplement it into the oil-side diaphragm cavity. Based on the above existing structure of the diaphragm compressor, the present invention adds a second piston 02B to the piston assembly. The second piston 02B is arranged on the piston rod 21 and reciprocates axially in the middle body 04A.

[0048] When the second piston 02B moves towards the direction close to the crankcase 04B, that is, towards the fuselage assembly, while the gas in the first chamber ⅠA starts to expand, on the one hand, the middle of the diaphragm 13 is evacuated, causing the three diaphragms 13 to fit together, increasing the gas chamber volume and the suction volume, thereby solving the problem of poor volumetric efficiency of the diaphragm compressor caused by the separation of the diaphragm 13; on the other hand, the oil sump in the crankcase 04B is evacuated, removing the bubbles contained in the oil in the oil sump of the crankcase 04B, increasing the elastic modulus of the hydraulic oil, avoiding the influence of the gas in the hydraulic oil on the actual volumetric efficiency of the high-pressure diaphragm compressor, and effectively improving the volumetric efficiency of the diaphragm compressor.

[0049] When the second piston 02B moves towards the direction close to the oil-side diaphragm head 01B, that is, towards the diaphragm head assembly, the gas in the first chamber ⅠA starts to be compressed, and the compressed gas is discharged from the first chamber ⅠA to the atmosphere.

[0050] In order to evacuate the diaphragm 13, discharge the gas in the diaphragm 13, and ensure that the diaphragm 13 is in a fitting state, a first through hole IIA communicating with the first chamber IA is provided on the middle body 04A, and a third through hole IIIA communicating with the diaphragm 13 is provided on the oil-side diaphragm head 01B. The third through hole IIIA and the first through hole IIA are communicated through a pipeline, and a first one-way valve 09 is arranged along the direction from the third through hole IIIA to the first through hole IIA. When the second piston 02B moves to the right, the volume of the first chamber IA becomes larger, discharging the gas in the diaphragm 13. As the gas is discharged, the diaphragm gradually becomes in a fitting state, increasing the volume of the air chamber and the air intake volume, thus solving the problem of poor volumetric efficiency of the diaphragm compressor caused by the separation of the diaphragm 13. When the second piston 02B moves to the left, the volume of the first chamber IA becomes smaller. Due to the setting of the first one-way valve 09, the gas in the first chamber IA cannot enter the diaphragm 13, so it is ensured that the diaphragm 13 is in a fitting state and does not affect the volumetric efficiency of the diaphragm compressor.

[0051] In order to discharge the bubbles contained in the oil in the oil sump of the crankcase 04B, increase the elastic modulus of the hydraulic oil, and avoid the problem of low actual volumetric efficiency of the high-pressure diaphragm compressor due to the gas in the hydraulic oil, a fourth through hole IIIB is provided on the crankcase 04B. The fourth through hole IIIB and the first through hole IIA are communicated through a pipeline, and a second one-way valve 11 is arranged along the direction from the fourth through hole IIIB to the first through hole IIA. When the second piston 02B moves to the right, the volume of the first chamber IA becomes larger, realizing the evacuation of the crankcase 04B. At this time, the bubbles contained in the oil in the oil sump of the crankcase 04B can be discharged, increasing the elastic modulus of the hydraulic oil, thus solving the problem of poor volumetric efficiency of the diaphragm compressor caused by the gas in the hydraulic oil. When the second piston 02B moves to the left, the volume of the first chamber IA becomes smaller. Due to the setting of the second one-way valve 11, the gas in the first chamber IA cannot enter the oil sump of the crankcase 04B, so the gas contained in the oil in the oil sump of the crankcase 04B is reduced and does not affect the volumetric efficiency of the diaphragm compressor.

[0052] In order to discharge the gas in the first chamber IA when the second piston 02B moves to the left, a second through hole IIB communicating with the first chamber IA is provided on the middle body 04A, and a third one-way valve 10 is arranged along the direction from the second through hole IIB to the atmosphere, so that the gas in the first chamber IA is discharged.

[0053] To achieve sealed gas, an oil cylinder sleeve is provided inside the diaphragm head assembly. An oil cylinder hole is provided inside the oil cylinder sleeve. The first piston 02A can axially reciprocate inside the oil cylinder hole. A sealing groove is machined on the side of the first piston 02A close to the fuselage assembly. A first sealing ring 07 is circumferentially provided inside the sealing groove. One end of the piston rod 21 extends into the first sealing ring 07 and abuts against the first piston 02A. The first sealing ring 07 is made of a material with relatively high hardness and wear resistance, and its function is to prevent the gas in the first chamber ⅠA of the accessory piston compressor from leaking to both sides.

[0054] To further achieve sealed gas, a sealing groove is machined circumferentially along the second piston 02B. A second sealing ring 08 is provided inside the sealing groove. The sealing ring 08 contacts the inner wall of the middle body 04A. The second sealing ring 08 is made of a material with relatively high hardness and wear resistance, and its function is to prevent the gas in the first chamber ⅠA of the accessory piston compressor from leaking to both sides.

[0055] To prevent the second piston 02B from hitting the cylinder, the stroke length of the second piston 02B moving axially is less than the axial length of the first chamber ⅠA.

[0056] To reduce the hydraulic oil pressure, a fifth through-hole ⅢC is also opened on the crankcase 04B. A safety valve 12 is connected to the fifth through-hole ⅢC. The fifth through-hole ⅢC is connected to the safety valve 12, and the pressure of the safety valve 12 is adjusted to remove the permitted pressure of the hydraulic oil. When the pressure is lower than this value, the safety valve 12 opens, and the atmosphere flows into the crankcase 04B. When the gas in the middle of the diaphragm 13 is also evacuated, the accessory piston mechanism does not work, reducing the additional energy consumption. If the atmosphere leaks into the middle of the three diaphragms 13 and the crankcase 04B, the safety valve 12 closes, and the system will continue to evacuate.

[0057] To prevent dry friction of the second piston 02B, an oil passage hole is opened inside the piston rod 21 for lubricating the second piston 02B.

[0058] Based on the above specific embodiment 1, when the piston assembly moves to the left, that is, moves towards the diaphragm head direction, the gas in the first chamber ⅠA is compressed. At this time, the first one-way valve 09 of the third through-hole ⅢA communicating with the diaphragm 13 and the second one-way valve 11 of the fourth through-hole ⅢB communicating with the fuselage assembly are both closed, and the third one-way valve 10 communicating with the atmosphere is opened to discharge the gas in the first chamber ⅠA to the atmosphere.

[0059] When the piston assembly moves to the right, that is, moves towards the fuselage assembly direction, the gas in the first chamber ⅠA starts to expand. At this time, the first one-way valve 09 of the third through-hole ⅢA communicating with the diaphragm 13 and the second one-way valve 11 of the fourth through-hole ⅢB communicating with the fuselage assembly are both opened, and the third one-way valve 10 communicating with the atmosphere is closed. The gas in the diaphragm 13 and the crankcase 04B of the fuselage assembly 04 is pumped into the first chamber ⅠA.

[0060] While the piston assembly reciprocates continuously, the chamber in the middle of the diaphragm 13 communicated with the third through-hole IIIA is continuously evacuated, and the separated diaphragm 13 gradually fits. When the vacuum degree in the third through-hole IIIA reaches the intake vacuum degree, the three diaphragms 13 are theoretically already fitted. Continuing to evacuate will improve the fitting degree of the three diaphragms 13. At this time, the three diaphragms 13 are closely fitted. During the intake process, the diaphragm 13 will return to the middle equilibrium position under the action of the pressure difference and its own resilience, the volume of the air chamber increases, and the overall volumetric efficiency of the machine is improved. At the same time, the first chamber IA communicated with the fourth through-hole IIIB is also continuously evacuated, and the gas mixed in the hydraulic oil is continuously sucked out. When the vacuum degree in the first chamber IA reaches a certain pressure, it is regarded that the gas content in the hydraulic oil reaches the permission. At this pressure, the safety valve 12 opens and maintains this pressure. At this time, the gas content rate of the hydraulic oil in the first chamber IA will maintain a lower permitted value and is supplied to the oil-side diaphragm head 01B through the piston pump assembly. At this time, the elastic modulus of the hydraulic oil during the compression process will be greatly increased, thereby improving the overall volumetric efficiency of the machine.

[0061] When the intake pressure is significantly higher than the atmospheric pressure, the diaphragm 13 will not separate, so the corresponding evacuation branch of the diaphragm 13 does not work.

[0062] In summary, the diaphragm compressor provided by the present invention continuously evacuates and discharges the gas from the air bag between the three diaphragms and the inside of the crankcase during the operation of the diaphragm compressor, solving the problem of low actual volumetric efficiency under high pressure.

[0063] Obviously, those skilled in the art can make various modifications and variations 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 its equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A diaphragm compressor, comprising a diaphragm head assembly, a piston assembly, a crosshead assembly (03) and a body assembly arranged in sequence along the axial direction, wherein the diaphragm head assembly comprises an air side diaphragm head (01A), an oil side diaphragm head (01B) and a diaphragm (13), and the body assembly comprises a middle body (04A) and a crankcase (04B) connected in sequence along the axial direction, characterized in that: The piston assembly comprises a piston rod (21), a first piston (02A) and a second piston (02B); The first piston (02A) reciprocates axially in the oil-side diaphragm head (01B); one end of the piston rod (21) extends into the oil-side diaphragm head (01B) and abuts against the first piston (02A), and the other end is connected to the crosshead assembly (03); the second piston (02B) is fixedly arranged on the piston rod (21), and the second piston (02B) reciprocates axially in the middle body (04A); The second piston (02B) divides the middle body (04A) into a first chamber (IA) close to the oil side diaphragm head (01B) and a second chamber (IB) far from the oil side diaphragm head (01B); the diaphragm (13) is connected to the first chamber (IA), and the first chamber (IA) is connected to the crankcase (04B); when the second piston (02B) moves toward the crankcase (04B), the gas in the diaphragm (13) and the gas in the oil pool in the crankcase (04B) enter the first chamber (IA), the diaphragm (13) fits, and the bubbles in the oil pool are removed; when the second piston (02B) moves toward the oil side diaphragm head (01B), the gas in the first chamber (IA) is discharged to the atmosphere.

2. The diaphragm compressor according to claim 1, characterized in that: A first through hole (ⅡA) communicating with the first chamber (IA) is provided on the middle body (04A), a third through hole (ⅢA) communicating with the diaphragm (13) is provided on the oil-side diaphragm head (01B), the third through hole (ⅢA) communicating with the first through hole (ⅡA) is connected through a pipeline, and a first one-way valve (09) is provided in the direction of flow from the third through hole (ⅢA) to the first through hole (ⅡA).

3. The diaphragm compressor according to claim 1, characterized in that: The crankcase (04B) is provided with a fourth through hole (IIIB), the fourth through hole (IIIB) is connected to the first through hole (IIA) through a pipeline, and a second one-way valve (11) is arranged along the direction from the fourth through hole (IIIB) to the first through hole (IIA).

4. The diaphragm compressor according to claim 1, characterized in that: A second through hole (IIB) communicating with the first chamber (IA) is provided on the middle body (04A), and a third one-way valve (10) is provided along the direction of the second through hole (IIB) flowing toward the atmosphere.

5. The diaphragm compressor according to claim 1, characterized in that: The diaphragm head assembly is provided with a cylinder sleeve, and a cylinder hole is provided in the cylinder sleeve. The first piston (02A) can axially reciprocate in the cylinder hole. A first sealing ring (07) is circumferentially provided in the cylinder hole close to the middle body (04A). One end of the piston rod (21) extends into the first sealing ring (07) and then abuts against the first piston (02A).

6. The diaphragm compressor according to claim 1, characterized in that: A second sealing ring (08) is provided along the circumferential direction at the contact end between the second piston (02B) and the middle body (04A).

7. The diaphragm compressor according to claim 1, characterized in that: The stroke length of the second piston (02B) moving in the axial direction is smaller than the axial length of the first chamber (IA).

8. The diaphragm compressor according to claim 1, characterized in that The crankcase (04B) is also provided with a fifth through hole (IIIC), and the fifth through hole (IIIC) is connected to a safety valve (12).

9. The diaphragm compressor according to claim 1, characterized in that: An oil hole is provided inside the piston rod for lubricating the second piston (02B).

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