Membrane head structure of small-flow half-cavity double-diaphragm compressor and operation method of membrane head structure

Abstract

The invention discloses a membrane head structure of a small-flow half-cavity double-membrane compressor and an operation method of the membrane head structure. The membrane head structure comprises a cylinder cover, a first oil distribution disc, a second oil distribution disc and a cylinder body which are fixedly connected together in sequence through membrane head connecting bolts; a gas side diaphragm group is arranged between the cylinder cover and the first oil distribution disc, and an oil side diaphragm group is arranged between the first oil distribution disc and the second oil distribution disc; a closed area defined by the cylinder cover and the air side diaphragm set forms an air side diaphragm cavity. A first oil cavity is formed in a closed area formed by the gas side diaphragm set, the oil side diaphragm set and the first oil distribution disc. A second oil cavity is formed in a closed area defined by the oil side diaphragm set, the second oil distribution disc, the cylinder body and the piston. The reciprocating motion of the piston drives the piston solid domain boundary of the second oil cavity and the diaphragm solid domain boundary to move, then the oil side diaphragm set, the first oil cavity, the gas side diaphragm set and the gas side diaphragm cavity are made to move, and due to the change of the volume cavity of the gas side diaphragm cavity, the gas compression, suction and exhaust processes of the diaphragm compressor are achieved. According to the invention, the service life of the diaphragm group is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of diaphragm compressors, and in particular relates to a diaphragm head structure of a small-flow half-cavity double-diaphragm compressor and an operating method thereof. Background Art

[0002] The diaphragm compressor is a positive displacement compressor driven by a crank-connecting rod mechanism. The crank-connecting rod mechanism converts the rotational motion of the motor and crankshaft into the reciprocating motion of the piston assembly. The piston assembly further converts its reciprocating motion into the flexural deformation of the diaphragm through the pressure transmission of the hydraulic oil. Finally, the change of the compression chamber of the diaphragm compressor is achieved by changing the volume of the diaphragm chamber with the diaphragm as the changing boundary, thereby realizing the suction, compression and exhaust process of the gas medium.

[0003] The traditional diaphragm compressor uses a single diaphragm group composed of three layers of diaphragms to separate the air cavity and the oil cavity, and uses leakage and pressure monitoring methods to warn of diaphragm rupture failures. During the normal operation of the diaphragm compressor, the oil pressure on both sides of the three-layer diaphragm is dynamically balanced, causing the diaphragm to deform, which in turn causes the change of the diaphragm head volume cavity, realizing the gas suction, compression and exhaust process. The traditional air cavity and oil cavity surfaces are single-exponential deflection curve surfaces, and the maximum activity space of the diaphragm is the air cavity and oil cavity surfaces. The single diaphragm group of the diaphragm compressor hits the air cavity surface in the overflow stage, and the single diaphragm group hits the oil side surface under oil shortage fault conditions. Therefore, the movement range of the diaphragm group of the traditional diaphragm compressor is the gas-liquid area composed of the oil cavity surface and the air cavity surface. Diaphragm life is a problem that is difficult to solve for traditional diaphragm compressors. Diaphragm rupture mainly occurs due to stress concentration at the edge of the diaphragm and when it hits the hole groove structure of the diaphragm cavity profile. Because in the design of the diaphragm cavity profile of traditional diaphragm compressors, the up and down movement of the diaphragm causes the stress at its edge to change alternately, especially when the diaphragm cavity index is selected to be large, the stress warping at the edge will accelerate the stress fatigue damage at the edge; when the diaphragm is operating under oil-deficient conditions, the diaphragm itself is at its maximum deformation point, and the circumferential and radial stresses are large. The additional stress generated by the diaphragm hitting the holes and grooves on the surface of the oil distribution plate causes the diaphragm to bear greater stress, increasing the possibility of diaphragm rupture. Summary of the invention

[0004] The purpose of the present invention is to solve the problems in the above-mentioned prior art of fatigue damage caused by alternating stress on the edge of the diaphragm of the diaphragm compressor and diaphragm rupture caused by stress concentration under oil-deficient conditions, and to provide a diaphragm head structure for a small-flow semi-cavity double diaphragm compressor and an operating method thereof. By improving the structure inside the diaphragm head cavity and adopting a double diaphragm group to separate the air cavity, the intermediate oil cavity and the driving oil cavity, the service life of the diaphragm group and the reliability of the diaphragm compressor as a whole are improved.

[0005] In order to achieve the above object, the present invention has the following technical solutions:

[0006] On the first aspect, a diaphragm head structure of a small-flow half-cavity double-diaphragm compressor is provided, comprising a cylinder head, a first oil distribution plate, a second oil distribution plate and a cylinder body which are fixedly connected together in sequence by diaphragm head connecting bolts, and a piston is installed on the cylinder body by a cylinder sleeve; an air side diaphragm group is arranged between the cylinder head and the first oil distribution plate, and an oil side diaphragm group is arranged between the first oil distribution plate and the second oil distribution plate; an air side diaphragm cavity is formed by a closed area surrounded by the cylinder head and the air side diaphragm group; a first oil cavity is formed by a closed area composed of the air side diaphragm group, the oil side diaphragm group and the first oil distribution plate; a second oil cavity is formed by a closed area composed of the oil side diaphragm group, the second oil distribution plate, the cylinder body and the piston; the reciprocating motion of the piston drives the movement of the solid domain boundary of the second oil cavity piston and the solid domain boundary of the diaphragm, thereby causing the movement of the oil side diaphragm group, the first oil cavity, the air side diaphragm group and the air side diaphragm cavity, and the gas compression, suction and exhaust processes of the diaphragm compressor are realized due to the change of the volume cavity of the air side diaphragm cavity.

[0007] As a preferred solution, the cylinder head and the first oil distribution plate, the first oil distribution plate and the second oil distribution plate, and the second oil distribution plate and the cylinder body are all assembled and positioned by right-angle positioning.

[0008] As a preferred solution, the air side diaphragm group is composed of three layers of diaphragms, which are positioned at right angles by the boss of the first oil distribution plate and sealed by the air side diaphragm sealing assembly;

[0009] The oil-side diaphragm group is composed of two layers of diaphragms, which are positioned at right angles by the boss of the first oil distribution plate and sealed by the oil-side diaphragm sealing assembly.

[0010] As a preferred solution, the cylinder head surface profile of the gas-side membrane cavity and the second oil distribution plate surface profile of the second oil cavity are generated by a single-exponential membrane cavity profile line with a membrane cavity index Z=3. The equation of the single-exponential membrane cavity profile line with a membrane cavity index Z=3 is as follows:

[0011] H(ρ)=H 0 (ρ 2 -1) 2

[0012] In the formula, H 0 represents the maximum deflection of the membrane cavity; ρ is the equivalent radius of the membrane cavity; H(ρ) is the deflection at the equivalent radius of the membrane cavity;

[0013] The upper surface profile of the first oil distribution plate and the lower surface profile of the first oil distribution plate of the first oil chamber are both planes.

[0014] As a preferred solution, the cylinder head is provided with an intake passage and an exhaust passage, the intake passage is composed of an intake valve and a gas passage in an intake valve column, and the exhaust passage is composed of an exhaust valve and a gas passage in an exhaust valve column;

[0015] The intake valve is compressed and sealed by the intake valve stem and the intake pressure valve cover plate, and the intake valve cover plate is compressed and fixed to the cylinder head by the diaphragm head compression bolts;

[0016] The exhaust valve is compressed and sealed by the exhaust valve column and the exhaust valve cover plate, and the exhaust valve cover plate is compressed and fixed to the cylinder head by the diaphragm head compression bolts.

[0017] As a preferred scheme, the first oil chamber is replenished with oil through the first plunger pump oil replenishing port, and oil overflows through the first overflow valve oil overflow port; the second oil chamber is replenished with oil through the second plunger pump oil replenishing port, and oil overflows through the second overflow valve oil overflow port, thereby achieving dynamic balance of the oil amount in the first oil chamber and the second oil chamber.

[0018] As a preferred solution, the oil replenishment amount m of the oil replenishment port of the second plunger pump is b2 The oil spill volume of the second overflow valve overflow port m y2 Hydraulic oil leakage from the piston m xl Decide to satisfy m b2 ≈m y2 >m xl ; The oil replenishment volume m of the first plunger pump oil replenishment port b1 The piston stroke volume V in the first oil chamber h , hydraulic oil density ρ l , standard atmospheric pressure p 0 Lower air solubility δ g 、Hydraulic oil gas content α l and the operating oil pressure p, satisfying

[0019] As a preferred solution, the first oil distribution plate is provided with a first oil distribution plate oil groove and a first oil distribution plate oil hole for circulating the hydraulic oil in the first oil chamber; the first oil distribution plate is also provided with a first oil distribution plate leakage monitoring through hole and a through groove and an oil pressure monitoring hole, the first oil distribution plate leakage monitoring through hole and the through groove are connected with the oil pressure monitoring hole, and the oil pressure monitoring hole is externally connected to an oil pressure detection sensor for monitoring diaphragm rupture; the first oil distribution plate is also provided with a first oil distribution plate leakage sealing groove for sealing the leakage of gas medium or hydraulic oil; the first oil distribution plate is also provided with an interface for connecting the first plunger pump and the first overflow valve, and is staggeredly connected with the oil holes of the first oil distribution plate;

[0020] The second oil distribution plate is provided with a second oil distribution plate oil inlet hole and a second oil distribution plate oil discharge hole for connecting the second plunger pump oil replenishing port and the second overflow valve oil overflow port. The second oil distribution plate is also provided with a second oil distribution plate oil hole and an oil groove for circulating the hydraulic oil in the second oil chamber.

[0021] In a second aspect, a method for operating a diaphragm head structure of a small flow half-cavity double diaphragm compressor is provided, comprising the following steps:

[0022] Inhalation process: The piston moves from the top dead center to the bottom dead center, the gas side diaphragm group moves from the cylinder head surface profile of the gas side diaphragm chamber to the upper surface profile close to the first oil distribution plate, and the oil side diaphragm group moves from the lower surface close to the first oil distribution plate to the second oil distribution plate surface profile close to the second oil chamber;

[0023] Compression process: The piston moves from the bottom dead center to the top dead center, the gas side diaphragm group moves from the upper surface of the first oil distribution plate close to the cylinder head surface of the gas side diaphragm cavity, and the oil side diaphragm group moves from the surface of the second oil distribution plate close to the second oil cavity to the lower surface of the first oil distribution plate;

[0024] Exhaust process: The piston moves from the bottom dead center to the top dead center, and the exhaust stops when the gas-side diaphragm group is in close contact with the cylinder head surface of the gas-side diaphragm cavity;

[0025] Oil overflow process: the piston moves from the bottom dead center to the top dead center. When the operating oil pressure in the cylinder is greater than the set oil overflow pressure, the hydraulic oil in the first oil chamber and the second oil chamber overflows through the first overflow port of the overflow valve and the second overflow port of the overflow valve respectively, until the air side diaphragm group is close to the cylinder head surface profile of the air side diaphragm chamber or the oil side diaphragm group is close to the lower surface of the first oil distribution plate.

[0026] As a preferred solution, when the first oil chamber is running without oil, the oil pressure in the first oil chamber drops to atmospheric pressure or even negative pressure, the air side diaphragm group is close to the upper surface of the first oil distribution plate, and the oil side diaphragm group is close to the lower surface of the first oil distribution plate;

[0027] When the second oil chamber is running without oil, the oil pressure in the second oil chamber drops to atmospheric pressure or even negative pressure. At this time, the air side diaphragm group is tightly attached to the upper surface of the first oil distribution plate, which limits the movement of the oil side diaphragm group. The oil pressure in the first oil chamber drops to a level close to the oil pressure in the second oil chamber, and the oil side diaphragm group will not be tightly attached to the surface of the second oil distribution plate of the second oil chamber.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] The diaphragm head structure of the small flow semi-cavity double diaphragm compressor of the present invention adopts a double diaphragm group to separate the air cavity, the middle oil cavity and the driving oil cavity. The stress direction of the double diaphragm diaphragm group remains unchanged during operation, avoiding fatigue damage caused by the alternation of traditional stress directions. The present invention adopts a double oil distribution plate structure to divide the oil cavity into a first oil cavity and a second oil cavity. The rupture of the oil side diaphragm group will not affect gas leakage, avoiding the danger caused by leakage of special gas media. The air cavity and the first oil cavity of the diaphragm head structure of the present invention adopt a semi-cavity structure, avoiding the risk of diaphragm rupture caused by stress concentration at the hole groove structure of the oil distribution plate when the traditional diaphragm compressor is in the oil shortage condition, while the diaphragm is in the maximum deflection deformation. In addition, the maximum deflection on the air side is determined by the diaphragm cavity profile of the air cavity cylinder head, reducing the possibility of diaphragm rupture on the air side under fault conditions, and improving the safety and reliability of traditional diaphragm compressors. The diaphragm compressor diaphragm head structure of the present invention adopts double diaphragms, double oil distribution plates, double oil circuits and air cavity half-cavity structures, thereby improving the problems of traditional diaphragm compressor diaphragms being easily broken due to impacting the oil distribution plate surface under oil shortage fault conditions and alternating fatigue damage on the edges under long-term operation conditions. At the same time, it solves the risk of oil and gas mixing caused by diaphragm rupture that may exist in traditional diaphragm compressors, ensures the life of the air side diaphragm group and the sealing of the air side diaphragm cavity, and improves the safety of the entire machine.

[0030] Furthermore, the diaphragm compressor diaphragm head structure of the present invention is particularly suitable for the transportation and compression of small flow special gases. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 This is a schematic diagram of the structure principle of the diaphragm head of a small flow half-cavity double diaphragm compressor according to an embodiment of the present invention;

[0033] Figure 2 A three-dimensional schematic diagram of the diaphragm head structure of a small flow half-cavity double diaphragm compressor according to an embodiment of the present invention;

[0034] Figure 3 It is a two-dimensional cross-sectional view of the membrane head structure of an embodiment of the present invention cut along the cross section G;

[0035] Figure 4 It is a two-dimensional cross-sectional view of the membrane head structure of an embodiment of the present invention cut along the cross section K;

[0036] FIG5( a ) is a schematic diagram of the three-dimensional structure of the first oil distribution plate according to an embodiment of the present invention;

[0037] FIG5( b ) is a two-dimensional cross-sectional view of the first oil distribution plate according to an embodiment of the present invention, taken along the cross section P;

[0038] FIG6( a ) is a schematic diagram of the three-dimensional structure of a second oil distribution plate according to an embodiment of the present invention;

[0039] FIG6( b ) is a two-dimensional cross-sectional view of the second oil distribution plate according to an embodiment of the present invention, taken along the cross section Q;

[0040] In the attached drawings: 1-cylinder head; 2-first oil distribution plate; 21-first oil distribution plate leakage monitoring through hole and through groove; 22-first oil distribution plate oil groove; 23-first oil distribution plate oil through hole; 24-first oil distribution plate diaphragm sealing groove; 25-first oil distribution plate leakage sealing groove; 3-second oil distribution plate; 31-second oil distribution plate oil inlet through hole; 32-second oil distribution plate oil discharge through hole; 33-second oil distribution plate oil through hole and oil groove; 34-second oil distribution plate diaphragm sealing groove; 4-cylinder body; 5-piston; 6-cylinder liner; 71-intake valve cover plate; 72-exhaust valve cover plate; 81-intake valve column; 82-exhaust valve column; 91-intake valve; 92-exhaust valve; Bo1-diaphragm head connecting bolt; Bo2-diaphragm head clamping bolt; GO-exhaust channel; GI-intake channel; LIA-first plunger pump oil replenishment port; LOA-first overflow valve oil overflow port; LIB-second plunger pump oil replenishment port; LOB-second overflow valve oil overflow port; Mo1-air side diaphragm group; Mo2-oil side diaphragm group; PL-oil pressure monitoring hole; SF1-cylinder head surface profile of air side diaphragm chamber; SF2-second oil distribution plate surface profile of second oil chamber; SF3-first oil distribution plate upper surface profile; SF4-first oil distribution plate lower surface; SG-air side diaphragm sealing assembly; SL-oil side diaphragm sealing assembly; YG-air side diaphragm chamber; YL1-first oil chamber; YL2-second oil chamber; G-first longitudinal cross section of diaphragm head; K-second longitudinal cross section of diaphragm head; P-transverse cross section of first oil distribution plate; Q-longitudinal cross section of second oil distribution plate. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] See also Figures 1 to 4The embodiment of the present invention proposes a diaphragm head structure of a small flow semi-cavity double diaphragm compressor, including a cylinder head 1, a first oil distribution plate 2, a second oil distribution plate 3 and a cylinder body 4 which are fixedly connected together in sequence by a diaphragm head connecting bolt Bo1, and a piston 5 is installed on the cylinder body 4 through a cylinder sleeve 6. An air-side diaphragm group Mo1 is arranged between the cylinder head 1 and the first oil distribution plate 2, and an oil-side diaphragm group Mo2 is arranged between the first oil distribution plate 2 and the second oil distribution plate 3; the closed area surrounded by the cylinder head 1 and the air-side diaphragm group Mo1 forms an air-side diaphragm chamber YG; the closed area composed of the air-side diaphragm group Mo1, the oil-side diaphragm group Mo2 and the first oil distribution plate 2 forms a first oil chamber YL1; the closed area surrounded by the oil-side diaphragm group Mo2, the second oil distribution plate 3, the cylinder body 4 and the piston 5 forms a second oil chamber YL2; the reciprocating motion of the piston 5 drives the movement of the solid domain boundary of the piston and the solid domain boundary of the diaphragm of the second oil chamber YL2, thereby causing the movement of the oil-side diaphragm group Mo2, the first oil chamber YL1, the air-side diaphragm group Mo1 and the air-side diaphragm chamber YG, and the gas compression, suction and exhaust processes of the diaphragm compressor are realized due to the change in the volume cavity of the air-side diaphragm chamber YG.

[0043] In a possible implementation manner, the cylinder head 1 and the first oil distribution plate 2 , the first oil distribution plate 2 and the second oil distribution plate 3 , and the second oil distribution plate 3 and the cylinder body 4 are all assembled and positioned by right-angle positioning.

[0044] Furthermore, the air-side diaphragm group Mo1 of the embodiment of the present invention is composed of three layers of diaphragms, which are positioned at right angles by the boss of the first oil distribution plate 2, as shown in FIG. 5(a), and are sealed by the air-side diaphragm sealing assembly SG.

[0045] The oil-side diaphragm group Mo2 of the embodiment of the present invention is composed of two layers of diaphragms, which are positioned at right angles by the boss of the first oil distribution plate 2 and sealed by the oil-side diaphragm sealing assembly SL.

[0046] In a possible implementation, the surface profile SF1 of the cylinder head 1 of the gas-side diaphragm chamber YG and the surface profile SF2 of the second oil distribution plate 3 of the second oil chamber YL2 are generated by a single-exponential diaphragm chamber profile with a diaphragm chamber index Z=3 of a conventional diaphragm compressor.

[0047] The single exponential diaphragm cavity profile equation of the traditional diaphragm compressor with diaphragm cavity index Z = 3 is as follows:

[0048] H(ρ)=H 0 (ρ 2 -1) 2

[0049] In the formula, H 0 represents the maximum deflection of the membrane cavity; ρ is the equivalent radius of the membrane cavity; H(ρ) is the deflection at the equivalent radius of the membrane cavity;

[0050] In the embodiment of the present invention, the upper surface profile SF3 of the first oil distribution plate 2 and the lower surface profile SF4 of the first oil distribution plate 2 of the first oil chamber YL1 are both planes.

[0051] In a possible implementation manner, the cylinder head 1 described in the embodiment of the present invention is provided with an intake channel GI and an exhaust channel GO, the intake channel GI is composed of an intake valve 91 and a gas passage inside the intake valve column 81, and the exhaust channel GO is composed of an exhaust valve 92 and a gas passage inside the exhaust valve column 82.

[0052] Furthermore, the intake valve 91 is compressed and sealed by the intake valve stem 81 and the intake valve cover plate 71, and the intake valve cover plate 71 is compressed and fixed to the cylinder head 1 by the diaphragm head compression bolts Bo2. The exhaust valve 92 is compressed and sealed by the exhaust valve stem 82 and the exhaust valve cover plate 72, and the exhaust valve cover plate 72 is compressed and fixed to the cylinder head 1 by the diaphragm head compression bolts Bo2.

[0053] In a possible implementation, the first oil chamber YL1 of the diaphragm compressor of the embodiment of the present invention is replenished with oil through the first plunger pump oil replenishing port LIA, and oil overflows through the first overflow valve oil overflow port LOA; the second oil chamber YL2 is replenished with oil through the second plunger pump oil replenishing port LIB, and oil overflows through the second overflow valve oil overflow port LOB, thereby achieving dynamic balance of the oil amounts in the first oil chamber YL1 and the second oil chamber YL2.

[0054] In a possible implementation manner, the oil replenishment amount m of the second plunger pump oil replenishment port LIB in the embodiment of the present invention is b2 The oil spill volume of the second overflow valve oil spill port LOB m y2 Hydraulic oil leakage from piston 5 m xl Decide to satisfy m b2 ≈m y2 >m xl ; The oil supply volume of the first plunger pump oil supply port LIA m b1 The piston stroke volume V in the first oil chamber YL1 h , hydraulic oil density ρ l , standard atmospheric pressure p 0 Lower air solubility δ g 、Hydraulic oil gas content α l and the operating oil pressure p, satisfying To ensure that the bubbles generated by the hydraulic oil in the first oil chamber YL1 are fully discharged.

[0055] Please refer to Figures 5(a) and 5(b). In the embodiment of the present invention, the first oil distribution plate 2 is provided with a first oil distribution plate oil groove 22 and a first oil distribution plate oil hole 23 for the circulation of hydraulic oil in the first oil chamber YL1; the first oil distribution plate 2 is also provided with a first oil distribution plate leakage monitoring hole and a through groove 21 and an oil pressure monitoring hole PL, the first oil distribution plate leakage monitoring through hole and the through groove 21 are connected with the oil pressure monitoring hole PL, and the oil pressure monitoring hole PL is externally connected to an oil pressure detection sensor for monitoring diaphragm rupture; the first oil distribution plate 2 is also provided with a first oil distribution plate leakage sealing groove 25 for sealing leakage of gas medium or hydraulic oil; the first oil distribution plate 2 is also provided with an interface for connecting the first plunger pump LIA and the first overflow valve LOA, which is cross-connected with the first oil distribution plate oil hole 23.

[0056] Please refer to Figures 6(a) and 6(b). In the embodiment of the present invention, the second oil distribution plate 3 is provided with a second oil distribution plate oil inlet hole 31 and a second oil distribution plate oil discharge hole 32 for connecting the second plunger pump oil replenishing port LIB and the second overflow valve oil overflow port LOB. In addition, the second oil distribution plate 3 is also provided with a second oil distribution plate oil hole and an oil groove 33 for circulating the hydraulic oil in the second oil chamber YL2.

[0057] The embodiment of the present invention further provides a method for operating a diaphragm head structure of a small flow half-cavity double diaphragm compressor, comprising the following steps:

[0058] Intake process: the piston 5 moves from the top dead center to the bottom dead center, the air side diaphragm group Mo1 moves from the surface profile SF1 of the cylinder head 1 of the air side diaphragm chamber YG to the upper surface profile SF3 close to the first oil distribution plate 2, and the oil side diaphragm group Mo2 moves from the lower surface SF4 close to the first oil distribution plate 2 to the surface profile SF2 of the second oil distribution plate 3 close to the second oil chamber YL2; compared with the traditional diaphragm compressor, the change in the diaphragm chamber volume of the diaphragm head structure of the embodiment of the present invention is half of that of the traditional diaphragm compressor, which is suitable for small flow application scenarios, and overcomes the disadvantage that the diaphragm of the traditional diaphragm compressor has a directional alternating stress load that reduces the life of the diaphragm.

[0059] Compression process: The piston 5 moves from the bottom dead center to the top dead center, the gas side diaphragm group Mo1 moves from the upper surface profile SF3 close to the first oil distribution plate 2 to the surface profile SF1 of the cylinder head 1 of the gas side diaphragm chamber YG, and the oil side diaphragm group Mo2 moves from the surface profile SF2 of the second oil distribution plate 3 close to the second oil chamber YL2 to the lower surface SF4 close to the first oil distribution plate 2;

[0060] Exhaust process: The piston 5 moves from the bottom dead center to the top dead center, and stops exhausting when the gas-side diaphragm group Mo1 is in close contact with the surface profile SF1 of the cylinder head 1 of the gas-side diaphragm chamber YG;

[0061] Oil overflow process: the piston 5 moves from the bottom dead center to the top dead center. When the operating oil pressure in the cylinder is greater than the set oil overflow pressure, the hydraulic oil in the first oil chamber YL1 and the second oil chamber YL2 overflows through the first overflow valve oil overflow port LOA and the second overflow valve oil overflow port LOB respectively, until the air side diaphragm group Mo1 is close to the surface profile SF1 of the cylinder head 1 of the air side diaphragm chamber YG or the oil side diaphragm group Mo2 is close to the lower surface SF4 of the first oil distribution plate 2.

[0062] In one possible implementation, when the first oil chamber YL1 is operating in the absence of oil, the oil pressure in the first oil chamber YL1 drops to atmospheric pressure or even negative pressure, the air side diaphragm group Mo1 is close to the upper surface SF3 of the first oil distribution plate 2, and the oil side diaphragm group Mo2 is close to the lower surface SF4 of the first oil distribution plate 2; this overcomes the excessive stress concentration of the diaphragm under the oil-deficient condition of the traditional diaphragm compressor, thereby increasing the life of the diaphragm.

[0063] In one possible embodiment, when the second oil chamber YL2 is running without oil, the oil pressure in the second oil chamber YL2 drops to atmospheric pressure or even negative pressure. At this time, the air side diaphragm group Mo1 is in close contact with the upper surface profile SF3 of the first oil distribution plate 2, which limits the movement of the oil side diaphragm group Mo2. The oil pressure of the first oil chamber YL1 drops to be close to the oil pressure of the second oil chamber YL2, and the oil side diaphragm group Mo2 will not be in close contact with the surface profile SF2 of the second oil distribution plate 3 of the second oil chamber YL2, thereby avoiding the problem of reduced diaphragm life due to large flexural deformation of the diaphragm and stress concentration at the stress hole groove of the oil distribution plate in traditional diaphragm compressors under oil-deficient conditions.

[0064] The diaphragm head structure of the small flow semi-cavity double diaphragm compressor of the present invention and the operation method thereof are beneficial to increasing the service life of the diaphragm group and the reliability of the diaphragm compressor as a whole, and provide an effective and feasible technical solution for the development of new diaphragm compressor models.

[0065] Although the present application is described above with reference to specific embodiments, it should be understood by those skilled in the art that many modifications may be made to the configurations and details disclosed in the present application within the principles and scope disclosed in the present application. The scope of protection of the present application is determined by the attached claims, and the claims are intended to cover all modifications included in the equivalent literal meaning or scope of the technical features in the claims.

Claims

1. A membrane head structure of a small flow semi-cavity double diaphragm compressor, characterized in that: The invention comprises a cylinder head (1), a first oil distribution plate (2), a second oil distribution plate (3) and a cylinder body (4) which are fixedly connected in sequence by a diaphragm head connecting bolt (Bo1); a piston (5) is mounted on the cylinder body (4) by a cylinder sleeve (6); an air side diaphragm group (Mo1) is arranged between the cylinder head (1) and the first oil distribution plate (2); an oil side diaphragm group (Mo2) is arranged between the first oil distribution plate (2) and the second oil distribution plate (3); a closed area surrounded by the cylinder head (1) and the air side diaphragm group (Mo1) forms an air side diaphragm cavity (YG); the air side diaphragm group (Mo1), the oil side diaphragm group (Mo2) and the first distribution plate (Bo1) form an air side diaphragm cavity (YG); The closed area formed by the oil pan (2) forms the first oil chamber (YL1); the closed area surrounded by the oil side diaphragm group (Mo2), the second oil distribution plate (3), the cylinder body (4) and the piston (5) forms the second oil chamber (YL2); the reciprocating motion of the piston (5) drives the movement of the solid domain boundary of the piston and the solid domain boundary of the diaphragm of the second oil chamber (YL2), thereby causing the movement of the oil side diaphragm group (Mo2), the first oil chamber (YL1), the air side diaphragm group (Mo1) and the air side diaphragm chamber (YG). Due to the change of the volume cavity of the air side diaphragm chamber (YG), the gas compression, suction and exhaust processes of the diaphragm compressor are realized.

2. The diaphragm head structure of the small flow half-cavity double diaphragm compressor according to claim 1 is characterized in that: The cylinder head (1) and the first oil distribution plate (2), the first oil distribution plate (2) and the second oil distribution plate (3), and the second oil distribution plate (3) and the cylinder body (4) are all assembled and positioned by right-angle positioning.

3. The diaphragm head structure of the small flow half-cavity double diaphragm compressor according to claim 1 is characterized in that: The air side diaphragm group (Mo1) is composed of three layers of diaphragms, which are positioned at right angles by the boss of the first oil distribution plate (2) and sealed by the air side diaphragm sealing assembly (SG); The oil-side diaphragm group (Mo2) is composed of two layers of diaphragms, which are positioned at right angles by the boss of the first oil distribution plate (2) and sealed by the oil-side diaphragm sealing assembly (SL).

4. The diaphragm head structure of the small flow half-cavity double diaphragm compressor according to claim 1 is characterized in that: The surface profile (SF1) of the cylinder head (1) of the gas side membrane cavity (YG) and the surface profile (SF2) of the second oil distribution plate (3) of the second oil cavity (YL2) are generated by a single exponential membrane cavity profile line with a membrane cavity index Z=3. The equation of the single exponential membrane cavity profile line with a membrane cavity index Z=3 is as follows: H(ρ)=H0(ρ 2 -1) 2 Where, H0 represents the maximum deflection of the membrane cavity; ρ is the equivalent radius of the membrane cavity; H(ρ) is the deflection at the equivalent radius of the membrane cavity; The upper surface profile (SF3) of the first oil distribution plate (2) of the first oil chamber (YL1) and the lower surface profile (SF4) of the first oil distribution plate (2) are both planes.

5. The diaphragm head structure of the small flow half-cavity double diaphragm compressor according to claim 1 is characterized in that: The cylinder head (1) is provided with an intake passage (GI) and an exhaust passage (GO), wherein the intake passage (GI) is composed of an intake valve (91) and a gas passage in an intake valve column (81), and the exhaust passage (GO) is composed of an exhaust valve (92) and a gas passage in an exhaust valve column (82); The air intake valve (91) is compressed and sealed by the air intake valve column (81) and the air intake pressure valve cover plate (71), and the air intake valve cover plate (71) is compressed and fixed to the cylinder head (1) by the membrane head compression bolt (Bo2); The exhaust valve (92) is compressed and sealed by the exhaust valve column (82) and the exhaust valve cover plate (72), and the exhaust valve cover plate (72) is compressed and fixed to the cylinder head (1) by the diaphragm head compression bolt (Bo2).

6. The diaphragm head structure of a small flow semi-cavity double diaphragm compressor according to claim 1 is characterized in that: The first oil chamber (YL1) is replenished with oil through the first plunger pump oil replenishing port (LIA), and oil overflows through the first overflow valve oil overflow port (LOA); the second oil chamber (YL2) is replenished with oil through the second plunger pump oil replenishing port (LIB), and oil overflows through the second overflow valve oil overflow port (LOB), thereby achieving dynamic balance of the oil amounts in the first oil chamber (YL1) and the second oil chamber (YL2).

7. The diaphragm head structure of the small flow semi-cavity double diaphragm compressor according to claim 6 is characterized in that: The oil replenishment volume of the second plunger pump replenishment port (LIB) m b2 The oil spill volume of the second overflow valve (LOB) is m y2 The hydraulic oil leakage from the piston (5) is m xl Decide to satisfy m b2 ≈m y2 >m xl ; The first plunger pump oil replenishment port (LIA) oil replenishment volume m b1 The piston stroke volume V in the first oil chamber (YL1) h , hydraulic oil density ρ l 、Air solubility δ at standard atmospheric pressure p0 g 、Hydraulic oil gas content α l and the operating oil pressure p, satisfying 8. The diaphragm head structure of a small flow half-cavity double diaphragm compressor according to claim 6 is characterized in that: The first oil distribution plate (2) is provided with a first oil distribution plate oil groove (22) and a first oil distribution plate oil hole (23) for circulating the hydraulic oil in the first oil chamber (YL1); the first oil distribution plate (2) is also provided with a first oil distribution plate leakage monitoring hole and a through groove (21) and an oil pressure monitoring hole (PL), the first oil distribution plate leakage monitoring hole and the through groove (21) are connected to the oil pressure monitoring hole (PL), and the oil pressure monitoring hole (PL) is externally connected to an oil pressure detection sensor for monitoring diaphragm rupture; the first oil distribution plate (2) is also provided with a first oil distribution plate leakage sealing groove (25) for sealing leakage of gas medium or hydraulic oil; the first oil distribution plate (2) is also provided with an interface for connecting the first plunger pump (LIA) and the first overflow valve (LOA), and is staggeredly connected with the first oil distribution plate oil hole (23); The second oil distribution plate (3) is provided with a second oil distribution plate oil inlet hole (31) and a second oil distribution plate oil discharge hole (32) for connecting the second plunger pump oil replenishment port (LIB) and the second overflow valve oil overflow port (LOB), and the second oil distribution plate (3) is also provided with a second oil distribution plate oil hole and an oil groove (33) for circulating the hydraulic oil in the second oil chamber (YL2).

9. A method for operating a diaphragm head structure of a small flow semi-cavity double diaphragm compressor, characterized in that: The following steps are involved: Inhalation process: the piston (5) moves from the top dead center to the bottom dead center, the gas side diaphragm group (Mo1) moves from the cylinder head (1) surface profile (SF1) of the gas side diaphragm chamber (YG) to the upper surface profile (SF3) close to the first oil distribution plate (2), and the oil side diaphragm group (Mo2) moves from the lower surface (SF4) close to the first oil distribution plate (2) to the surface profile (SF2) of the second oil distribution plate (3) close to the second oil chamber (YL2); Compression process: the piston (5) moves from the bottom dead center to the top dead center, the gas side diaphragm group (Mo1) moves from the upper surface profile (SF3) close to the first oil distribution plate (2) to the surface profile (SF1) of the cylinder head (1) of the gas side diaphragm chamber (YG), and the oil side diaphragm group (Mo2) moves from the surface profile (SF2) of the second oil distribution plate (3) close to the second oil chamber (YL2) to the lower surface (SF4) close to the first oil distribution plate (2); Exhaust process: The piston (5) moves from the bottom dead center to the top dead center, and stops exhausting when the gas-side diaphragm group (Mo1) is in close contact with the surface profile (SF1) of the cylinder head (1) of the gas-side diaphragm chamber (YG); Oil overflow process: the piston (5) moves from the lower dead center to the upper dead center. When the operating oil pressure in the cylinder is greater than the set oil overflow pressure, the hydraulic oil in the first oil chamber (YL1) and the second oil chamber (YL2) overflows through the first overflow valve oil overflow port (LOA) and the second overflow valve oil overflow port (LOB) respectively, until the air side diaphragm group (Mo1) is close to the cylinder head (1) surface profile (SF1) of the air side diaphragm chamber (YG) or the oil side diaphragm group (Mo2) is close to the lower surface (SF4) of the first oil distribution plate (2).

10. The operating method of the membrane head structure of a small flow half-cavity double diaphragm compressor according to claim 9 is characterized in that: When the first oil chamber (YL1) is running without oil, the oil pressure in the first oil chamber (YL1) drops to atmospheric pressure or even negative pressure, the air side diaphragm group (Mo1) is closely attached to the upper surface (SF3) of the first oil distribution plate (2), and the oil side diaphragm group (Mo2) is close to the lower surface (SF4) of the first oil distribution plate (2); When the second oil chamber (YL2) is running without oil, the oil pressure in the second oil chamber (YL2) drops to atmospheric pressure or even negative pressure. At this time, the air side diaphragm group (Mo1) is in close contact with the upper surface profile (SF3) of the first oil distribution plate (2), which restricts the movement of the oil side diaphragm group (Mo2). The oil pressure of the first oil chamber (YL1) drops to a level close to the oil pressure of the second oil chamber (YL2), and the oil side diaphragm group (Mo2) will not be in close contact with the surface profile (SF2) of the second oil distribution plate (3) of the second oil chamber (YL2).

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