Diaphragm compressor with two-stage counter-moving plunger pump structure and design method of diaphragm compressor

Abstract

The invention discloses a diaphragm compressor with a two-stage counter-moving plunger pump structure and a design method of the diaphragm compressor. The diaphragm compressor comprises a first-stage plunger pump and a second-stage plunger pump, and the first-stage plunger pump and the second-stage plunger pump are installed on the two symmetrical sides of a compressor end cover correspondingly; hydraulic oil sealing is carried out between plunger pump bodies of the first-stage plunger pump and the second-stage plunger pump and a compressor end cover, between the plunger pump bodies and plunger pump linings, between the plunger pump bodies and plunger pump covers and between the plunger pump linings and plunger pump plungers in the plunger pump linings. The first-stage plunger pump and the second-stage plunger pump are driven by the eccentric wheel structure, and under the combined action of the counter-acting force of the plunger pump springs and the friction force of the plunger pumps, the oil feeding process, the pressure increasing process, the oil discharging process and the pressure reducing process are achieved. According to the method, the diameter and the stroke of the plunger of the plunger pump can be determined, the minimum spring force needed by the spring of the plunger pump and the optimal mounting angle range of the two-stage plunger pump can be determined, and a design scheme, performance prediction and optimization directions are provided for prolonging the service life of the plunger pump, improving the reliability of the plunger pump and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of diaphragm compressors, and in particular relates to a diaphragm compressor with a two-stage opposing piston pump structure and a design method thereof. Background Art

[0002] A diaphragm compressor is a positive displacement compressor that uses a diaphragm to separate the oil side and the gas side. Its working principle is: the motor drives the crankshaft connecting rod, which drives the piston to reciprocate to achieve pressurization and decompression of the high-pressure oil, and then the high-pressure oil pushes the diaphragm to achieve gas compression and discharge. Diaphragm compressors are widely used in the hydrogen energy industry due to their good sealing and high pressure ratio. In particular, hydrogen refueling stations are one of their important usage scenarios. The diaphragm life, volumetric efficiency and diaphragm head strength are very critical and difficult issues in the development of diaphragm compressors.

[0003] The oil replenishment, hydraulic and lubrication systems of the diaphragm compressor directly affect the operational reliability of the entire machine. The hydraulic oil in the diaphragm head assembly is driven by the piston driven by the crank-connecting rod mechanism, which not only directly affects the gas side pressure and exhaust volume, but also directly acts on the diaphragm to cause its flexural deformation, and more directly acts on the diaphragm head assembly to affect its strength and reliability. When the diaphragm compressor is running, the high-pressure hydraulic oil will inevitably leak through the piston ring, which will directly lead to an increase in the clearance and a decrease in the gas volume of the diaphragm compressor, or even a loss of air compression capacity. Therefore, the diaphragm compressor needs to be equipped with an oil replenishment plunger pump to replenish the amount of hydraulic oil in the diaphragm head. The replenishment plunger pump is generally driven by the crankshaft shaft head eccentric wheel, and forms a certain phase difference with the piston operation in the crankcase to replenish the oil. The traditional diaphragm compressor generally sets the phase difference to 0° or 180°, that is, the plunger pump performs the plunger pump oil replenishment operation during the suction or exhaust stroke of the diaphragm compressor. The patent with publication number CN109469603B proposes a high-pressure diaphragm compressor and its oil replenishment system and oil replenishment method. By externally connecting an overflow valve passage between the oil replenishment plunger pump and the oil replenishment check valve, the oil replenishment oil pressure control of the diaphragm compressor's suction stroke or exhaust stroke is achieved, thereby achieving regulation of the plunger pump's oil replenishment amount.

[0004] In the oil replenishment system, the plunger pump stroke volume is generally designed to be larger than the hydraulic oil leakage in the cylinder. However, excessive plunger pump oil replenishment will affect the suction volume and cause insufficient single-turn suction volume. The oil replenishment amount is one of the key issues to ensure the stable operation of the diaphragm compressor. How to reasonably set the plunger pump stroke volume is a difficult problem in the current diaphragm compressor design stage. Summary of the invention

[0005] The purpose of the present invention is to provide a two-stage opposing piston pump structure diaphragm compressor and a design method thereof in order to solve the problems in the above-mentioned prior art, thereby improving the service life of the diaphragm compressor plunger pump and the overall reliability of the diaphragm compressor.

[0006] In order to achieve the above object, the present invention has the following technical solutions:

[0007] A two-stage opposing piston pump structure diaphragm compressor comprises a compressor end cover, a primary piston pump, a secondary piston pump, a piston pump connecting bolt, a primary eccentric wheel structure and a secondary eccentric wheel structure; the primary piston pump and the secondary piston pump are respectively installed on the symmetrical sides of the compressor end cover through the piston pump connecting bolts to achieve dynamic balance; hydraulic oil sealing is performed through sealing rings between the piston pump body and the compressor end cover, between the piston pump body and the piston pump bushing, between the piston pump body and the piston pump cover, and between the piston pump bushing and the internal piston pump plunger of the primary piston pump and the secondary piston pump; the primary piston pump and the secondary piston pump are respectively driven by the primary eccentric wheel structure and the secondary eccentric wheel structure and the reaction force of the piston pump spring and the friction force of the piston pump plunger to achieve the process of oil intake, pressurization, oil discharge and pressure reduction of the piston pump.

[0008] As a preferred scheme, the hydraulic oil is sealed between the plunger pump body of the first-stage plunger pump and the second-stage plunger pump and the compressor end cover through the sealing ring in the fourth sealing groove of the plunger pump body, the hydraulic oil is sealed between the plunger pump body and the plunger pump bushing through the sealing ring in the second sealing groove of the plunger pump body and the third sealing groove of the plunger pump body, the hydraulic oil is sealed between the plunger pump cover and the plunger pump body through the sealing ring in the first sealing groove of the plunger pump body, and the hydraulic oil is sealed between the plunger pump bushing and the plunger pump plunger through the sealing rings in multiple plunger sealing grooves.

[0009] As a preferred solution, the first-stage plunger pump and the second-stage plunger pump are driven by the first-stage eccentric wheel structure and the second-stage eccentric wheel structure respectively, and the plunger pump plunger moves in the direction of the plunger pump spring compression. In this process, the volume of the plunger pump oil chamber is reduced, thereby realizing the process of pressurizing and discharging the hydraulic oil in the plunger pump oil chamber. At the same time, the plunger pump spring provides a reaction force to counter the eccentric wheel driving force and the plunger pump plunger friction force. When the plunger pump plunger moves to the top dead center position, the plunger pump plunger, driven by the plunger pump spring, counteracts the eccentric wheel reaction force and the plunger pump plunger friction force, and pushes the plunger pump plunger to move to the bottom dead center. In this process, the volume of the plunger pump oil chamber is increased, thereby realizing the process of decompressing and filling the hydraulic oil in the plunger pump oil chamber until the plunger pump plunger reaches the bottom dead center position.

[0010] As a preferred solution, the volume of the volume chamber of the first-stage plunger pump and the second-stage plunger pump is greater than the gap L of the diaphragm compressor piston leakage channel. xl The amount of leakage;

[0011] Diaphragm compressor piston leakage channel clearance L xl The leakage is calculated according to the following formula:

[0012]

[0013] In the formula, Q l is the gap L of the diaphragm compressor piston leakage channel xl Leakage flow; d hs is the diameter of the diaphragm compressor piston; δ is the gap L of the diaphragm compressor piston leakage channel xl The gap; μ is the viscosity of the hydraulic oil; l is the gap L of the leakage channel of the diaphragm compressor piston xl Δp is the gap L of the diaphragm compressor piston leakage channel xl The pressure difference on both sides; p oil is the maximum oil pressure of the diaphragm compressor; p air is the atmospheric pressure; m is the number of sealing rings on the diaphragm compressor piston.

[0014] As a preferred solution, the volume of the volume chamber of the primary plunger pump and the secondary plunger pump is calculated according to the following formula:

[0015]

[0016] In the formula, m 柱塞 The oil replenishment volume of the primary plunger pump or the secondary plunger pump; m l is the leakage mass of the gap in the leakage channel of the diaphragm compressor piston; m is the design coefficient, greater than 1; ρ oil is the density of hydraulic oil; d zs L is the diameter of the plunger pump plunger; zs is the stroke of the plunger pump plunger.

[0017] As a preferred solution, the reaction force of the plunger pump spring is calculated according to the following formula:

[0018]

[0019] In the formula, F spring,min is the minimum spring force of the plunger pump spring at the bottom dead center position; E is the elastic modulus of the sealing ring in the plunger sealing groove; H is the wire diameter of the sealing ring in the plunger sealing groove; h is the groove depth of the sealing ring in the plunger sealing groove; D is the inner diameter of the sealing ring in the plunger sealing groove; b is the width of the sealing groove in the plunger sealing groove; μ is the Poisson's ratio of the sealing ring in the plunger sealing groove; l is the characteristic length of the plunger pump plunger in the axial direction in contact with the leaking hydraulic oil; ν is the kinematic viscosity of the hydraulic oil; ρ is the density of the hydraulic oil; u is the moving speed of the plunger pump plunger; s is the circumferential clearance of the plunger pump plunger.

[0020] As a preferred solution, there is a phase difference between the reciprocating motion direction of the diaphragm compressor piston and the reciprocating motion direction of the plunger pump plunger, and the phase difference is determined by the pressure values ​​of the relative high pressure and the relative low pressure of the diaphragm compressor; the relative high pressure and the relative low pressure of the diaphragm compressor are calculated according to the following formula:

[0021]

[0022] In the formula, p relative,high is relatively high pressure; h is the relative high pressure coefficient; p oil,max is the maximum oil pressure; l is the relative low pressure coefficient; p stage,1 is the instantaneous oil pressure of the first stage of the diaphragm compressor; p stage,2 is the instantaneous oil pressure of the second stage of the diaphragm compressor; t s is the phase angle of the diaphragm compressor overflow valve oil replenishment start, t e It is the phase angle at which the oil replenishment of the diaphragm compressor relief valve ends.

[0023] As a preferred solution, the primary plunger pump and the secondary plunger pump are installed symmetrically at 180 degrees, and the relative high pressure coefficient χ h and the relative low pressure coefficient χ l , so that the diaphragm compressor overflow valve oil replenishment start phase angle t s The phase angle t of the diaphragm compressor overflow valve oil supply end e satisfy:

[0024]

[0025] As a preferred solution, the relative movement direction of the primary plunger pump and the secondary plunger pump and the relative movement direction of the piston movement of the two-stage opposing diaphragm compressor have a phase angle It meets the following relationship:

[0026]

[0027] The first stage of the diaphragm compressor Inhale within the time frame, The best time for the plunger pump to start replenishing oil to the membrane head is [t1,t s ] moment, the best time for the plunger pump to start oiling is [t e ,T]∪[0,t1].

[0028] A design method for a two-stage opposing piston pump structure diaphragm compressor as described above comprises the following steps:

[0029] Definition of cylinder oil pressure p stage , then the dimensionless oil pressure is described as Here we take the maximum oil pressure poil,max For the design of nominal discharge pressure for diaphragm compressors, the nominal dimensionless oil pressure is described as The dimensionless oil pressure of the diaphragm compressor is calculated by the thermal process simulation with the crank angle The change curve of the relative high pressure coefficient χ h and the relative low pressure coefficient χ l , so that the diaphragm compressor overflow valve oil replenishment start phase angle t s The phase angle t of the diaphragm compressor overflow valve oil supply end e satisfy:

[0030]

[0031] Determine the phase angle between the relative motion direction of the primary and secondary piston pumps and the relative motion direction of the pistons of the two-stage opposing diaphragm compressor Determine the installation angle range of the first-stage plunger pump and the second-stage plunger pump.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] The first-stage plunger pump and the second-stage plunger pump of the diaphragm compressor of the two-stage opposing plunger pump structure of the present invention are driven by the first-stage eccentric wheel structure and the second-stage eccentric wheel structure respectively, and the reaction force of the plunger pump spring and the friction force of the plunger pump plunger jointly act to realize the process of oil intake, pressurization, oil discharge and decompression of the plunger pump. The diameter and stroke of the plunger pump of the diaphragm compressor can be determined, the minimum spring force required by the spring of the diaphragm compressor plunger pump can be determined to match the overall structural dimensions of the designed plunger pump, and the optimal installation angle range of the two-stage plunger pump can be determined to minimize the working pressure of the plunger pump and maximize the oil replenishment amount, so as to provide a structural design scheme, performance prediction and optimization direction for improving the service life and reliability of the plunger pump. The two-stage opposing plunger pump structure diaphragm compressor designed by the present invention has a simple structure, a small size, is flexible and convenient to use, and is easy to be produced in series or customized.

[0034] Furthermore, the two-stage opposed piston pump structure diaphragm compressor of the present invention adopts a simplified method of the hydraulic oil leakage gap channel model to quantitatively describe and calculate the oil chamber leakage of the diaphragm compressor, and quantitatively describes and calculates the plunger pump chamber stroke volume through a correction coefficient method, replacing the method of determining the plunger pump stroke volume by the empirical ratio of the oil chamber volume.

[0035] Furthermore, the present invention quantitatively describes and calculates the minimum spring force required for the operation of the plunger pump by considering the friction force of the plunger pump sealing ring and the viscous friction force of the hydraulic oil, thereby optimizing the selection of the plunger pump spring.

[0036] Furthermore, the present invention takes the minimum working pressure of the plunger pump as the optimization goal, quantitatively describes and calculates the optimal installation phase difference of the two-stage diaphragm compressor plunger pump, and determines the optimal time range for oil injection of the plunger pump and the time to start oil replenishment, which is beneficial to improving the service life of the diaphragm compressor plunger pump and the reliability of the diaphragm compressor as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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.

[0038] Figure 1 It is a schematic diagram of the overall cross-sectional structure of a two-stage plunger pump and an end cover of a two-stage opposed-moving diaphragm compressor according to an embodiment of the present invention;

[0039] Figure 2 It is an enlarged schematic diagram of the cross-sectional structure of a primary plunger pump according to an embodiment of the present invention;

[0040] Figure 3 It is a cross-sectional schematic diagram of the piston and cylinder sleeve assembly and the gap leakage channel according to an embodiment of the present invention;

[0041] Figure 4 Schematic diagram of the optimal oil replenishment timing for the plunger pump according to an embodiment of the present invention;

[0042] Figure 5 The first-stage oil pressure and air pressure characteristic change curve of the diaphragm compressor according to the embodiment of the present invention;

[0043] Figure 6 The dimensionless oil pressure variation curve of the two-stage diaphragm compressor with the crank angle obtained by AMESim simulation calculation according to the embodiment of the present invention;

[0044] In the attached figure: A-compressor end cover; B1-first-stage plunger pump; B2-second-stage plunger pump; C-plunger pump connecting bolt; D1-first-stage eccentric wheel structure; D2-second-stage eccentric wheel structure; E-piston cylinder sleeve; F-piston; L xl -Gap of the leakage channel of the diaphragm compressor piston; 1-plunger pump body; 11-first sealing groove of the plunger pump body; 12-second sealing groove of the plunger pump body; 13-third sealing groove of the plunger pump body; 14-fourth sealing groove of the plunger pump body; 15-oil groove of the plunger pump body; 2-plunger pump cover; 3-plunger pump bushing; 4-plunger pump spring; 5-plunger pump plunger; 51-plunger sealing groove; 6-plunger pump oil inlet; 7-plunger pump oil outlet. DETAILED DESCRIPTION

[0045] 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.

[0046] See also Figure 1 The embodiment of the present invention proposes a two-stage opposing piston pump structure diaphragm compressor, including a compressor end cover A, a primary piston pump B1, a secondary piston pump B2, a piston pump connecting bolt C, a primary eccentric wheel structure D1 and a secondary eccentric wheel structure D2. The primary plunger pump B1 and the secondary plunger pump B2 are respectively installed on the symmetrical sides of the compressor end cover A through the plunger pump connecting bolts C to achieve dynamic balance; the primary plunger pump B1 and the secondary plunger pump B2 are sealed with hydraulic oil through sealing rings between the plunger pump body 1 and the compressor end cover A, between the plunger pump body 1 and the plunger pump bushing 3, between the plunger pump body 1 and the plunger pump cover 2, and between the plunger pump bushing 3 and the internal plunger pump plunger 5; the primary plunger pump B1 and the secondary plunger pump B2 are driven by the primary eccentric wheel structure D1 and the secondary eccentric wheel structure D2, and the reaction force of the plunger pump spring 4 and the friction force of the plunger pump plunger 5 respectively, to achieve the process of oil intake, pressurization, oil discharge and pressure reduction of the plunger pump.

[0047] See also Figure 2 In a possible implementation manner, the plunger pump body 1 of the primary plunger pump B1 and the secondary plunger pump B2 and the compressor end cover A are sealed with hydraulic oil through the sealing ring in the fourth sealing groove 14 of the plunger pump body, the plunger pump body 1 and the plunger pump bushing 3 are sealed with hydraulic oil through the sealing ring in the second sealing groove 12 of the plunger pump body and the third sealing groove 13 of the plunger pump body, the plunger pump cover 2 and the plunger pump body 1 are sealed with hydraulic oil through the sealing ring in the first sealing groove 11 of the plunger pump body, and the plunger pump bushing 3 and the plunger pump plunger 5 are sealed with hydraulic oil through the sealing ring in the six plunger sealing grooves 51.

[0048] Furthermore, the first-stage plunger pump B1 and the second-stage plunger pump B2 of the embodiment of the present invention are driven by the first-stage eccentric wheel structure D1 and the second-stage eccentric wheel structure D2 respectively, and the plunger pump plunger 5 moves in the compression direction of the plunger pump spring 4. In this process, the volume of the plunger pump oil chamber is reduced, thereby realizing the pressurization and oil discharge process of the hydraulic oil in the plunger pump oil chamber. At the same time, the plunger pump spring 4 provides a reaction force to counteract the eccentric wheel driving force and the friction force of the plunger pump plunger 5. When the plunger pump plunger 5 moves to the top dead center position, the plunger pump plunger 5 is driven by the plunger pump spring 4 to counteract the eccentric wheel reaction force and the friction force of the plunger pump plunger 5, and pushes the plunger pump plunger 5 to move to the bottom dead center. In this process, the volume of the plunger pump oil chamber is increased, thereby realizing the decompression and oil filling process of the hydraulic oil in the plunger pump oil chamber, until the plunger pump plunger 5 reaches the bottom dead center position. This process is repeated to realize the process of oil intake, pressure increase, oil discharge and pressure reduction of the primary plunger pump B1 and the secondary plunger pump B2.

[0049] In a possible implementation manner, the volume of the volume chamber of the first-stage plunger pump B1 and the second-stage plunger pump B2 of the embodiment of the present invention is greater than the gap L of the leakage channel of the diaphragm compressor piston. xl The leakage amount of the gap leakage channel is similar to the gap of the concentric cylindrical annulus. Then the gap L of the diaphragm compressor piston leakage channel xl The leakage is calculated according to the following formula:

[0050]

[0051] In the formula, Q l is the gap L of the diaphragm compressor piston leakage channel xl Leakage flow rate, in kg·s -1 ;d hs is the diameter of the diaphragm compressor piston F, in m; δ is the gap L of the diaphragm compressor piston leakage channel xl The gap, in m;

[0052] μ is the viscosity of the hydraulic oil, in Pa·s; l is the gap L of the diaphragm compressor piston leakage channel xl The length of the , in m;

[0053] Δp is the gap L of the diaphragm compressor piston leakage channel xl The pressure difference on both sides is in Pa; p oil is the maximum oil pressure of the diaphragm compressor, in Pa; p air is the atmospheric pressure, in Pa; m is the number of sealing rings on the diaphragm compressor piston F, in pieces.

[0054] Furthermore, the volume chamber volumes of the primary plunger pump B1 and the secondary plunger pump B2 are calculated according to the following formula:

[0055]

[0056] In the formula, m 柱塞 The oil replenishment volume of the primary plunger pump B1 or the secondary plunger pump B2, in kg; m l is the leakage mass of the gap of the diaphragm compressor piston leakage channel, in kg; X m is the design coefficient, greater than 1, preferably 3 to 5; oil is the hydraulic oil density, in kg·m -3 ;d zs is the diameter of the plunger pump plunger 5, in m; L zs Q is the stroke of the plunger pump plunger 5, in meters. l =m l *T, T=60 / n, T is the reciprocating cycle time of the diaphragm compressor piston, in seconds, and n is the rotation speed of the diaphragm compressor, in r / min.

[0057] The above method can be used to determine the diameter and stroke of the plunger 5 of the diaphragm compressor plunger pump, thereby determining the basic design parameters of the primary plunger pump B1 and the secondary plunger pump B2.

[0058] In one possible implementation, the design and selection of the plunger pump spring 4 needs to consider that the spring force when the plunger pump plunger 5 is preparing to move from the top dead center to the bottom dead center is greater than the static friction it is subjected to, and that the spring force during the movement of the plunger pump plunger 5 from the top dead center to the bottom dead center must always be greater than the sliding friction it is subjected to. Since the difference between the static friction and the sliding friction is much smaller than the absolute change in the spring force, only the friction of the plunger pump during the sliding process is considered to select the plunger pump spring. The friction of the plunger pump is mainly composed of the sliding friction caused by the compression reaction force of the sealing ring and the viscous movement friction caused by the leakage of hydraulic oil. The minimum spring force of the plunger pump spring 4 can be specifically described as the following formula:

[0059]

[0060] In the formula, F spring,min is the minimum spring force of the plunger pump spring 4 at the bottom dead center position, in N; E is the elastic modulus of the sealing ring in the plunger sealing groove, in Pa; H is the wire diameter of the sealing ring in the plunger sealing groove, in m; h is the groove depth of the sealing ring in the plunger sealing groove, in m; D is the inner diameter of the sealing ring in the plunger sealing groove, in m; b is the width of the sealing groove in the plunger sealing groove, in m; μ is the Poisson's ratio of the sealing ring in the plunger sealing groove; l is the characteristic length of the plunger pump plunger 5 in the axial direction in contact with the leaking hydraulic oil, in m; v is the kinematic viscosity of the hydraulic oil, in mm 2 ·s -1 ; ρ is the density of hydraulic oil, unit is kg·m -3; u is the moving speed of the plunger pump plunger 5, the unit is m·s -1 ; s is the circumferential clearance of the plunger pump plunger 5, unit is m.

[0061] The above method can be used to determine the minimum spring force required by the plunger pump spring 4 of the diaphragm compressor, thereby determining the specific parameters of the plunger pump spring 4 in coordination with the overall structural dimensions of the designed first-stage plunger pump B1 and second-stage plunger pump B2.

[0062] See also Figure 4 In a possible implementation manner, there is a certain phase difference between the reciprocating motion direction of the piston of the diaphragm compressor of the embodiment of the present invention and the reciprocating motion direction of the plunger 5 of the plunger pump, and the phase difference is determined by the pressure values ​​of the relative high pressure and the relative low pressure of the diaphragm compressor; the relative high pressure and the relative low pressure of the diaphragm compressor are calculated according to the following formula:

[0063]

[0064] In the formula, p relative,high is the relative high pressure, the unit is Pa; h is the relative high pressure coefficient, preferably 0.3 to 0.8; oil,max is the maximum oil pressure, in Pa; l is a relatively low pressure coefficient, preferably 0.2 to 0.6; p stage,1 is the instantaneous oil pressure of the first stage of the diaphragm compressor, in Pa; p stage,2 is the instantaneous oil pressure of the second stage of the diaphragm compressor, in Pa; t s is the phase angle of the diaphragm compressor overflow valve oil replenishment start, t e It is the phase angle at which the oil replenishment of the diaphragm compressor relief valve ends.

[0065] Furthermore, in the embodiment of the present invention, the first-stage plunger pump B1 and the second-stage plunger pump B2 are installed symmetrically at 180 degrees. h and relative low pressure coefficient X l , so that the diaphragm compressor overflow valve oil replenishment start phase angle t s The phase angle t of the diaphragm compressor overflow valve oil supply end e satisfy:

[0066]

[0067] There is a phase angle between the relative movement direction of the primary plunger pump B1 and the secondary plunger pump B2 and the relative movement direction of the piston of the two-stage diaphragm compressor. It meets the following relationship:

[0068]

[0069] The above method can be used to determine the optimal installation angle range of the first-stage plunger pump B1 and the second-stage plunger pump B2 of the two-stage opposed diaphragm compressor. This installation angle can minimize the working pressure of the plunger pump and maximize the oil replenishment amount.

[0070] Further, such as Figure 5 As shown, the first stage of the two-stage opposed diaphragm compressor is Inhale within the time frame, The compressed air is exhausted within the time range. The above method can be used to determine the best time for the plunger pump to start replenishing oil to the membrane head at [t1,t s ] moment, the best time for the plunger pump to start oiling is [t e ,T]∪[0,t1], and the same is true for the design of the second-stage piston pump.

[0071] See also Figure 6 Another embodiment of the present invention further provides a design method for a two-stage opposing piston pump structure diaphragm compressor as described above, comprising the following steps:

[0072] Definition of cylinder oil pressure p stage , then the dimensionless oil pressure is described as Here we take the maximum oil pressure p oil,max For the design of nominal discharge pressure for diaphragm compressors, the nominal dimensionless oil pressure is described as The dimensionless oil pressure of the diaphragm compressor with the crank angle is obtained by the thermodynamic process simulation based on AMESim. The change curve of the relative high pressure coefficient X h =0.6, relative low pressure coefficient χ l =0.2, its intersection points with the first-level dimensionless oil pressure curve are A1, B1, C1, D1, and its focus with the second-level dimensionless oil pressure curve is A2, B2, C2, D2, and the calculation results are According to the above-mentioned relief valve design method, the best oil replenishment start phase angle t of the first and second relief valves is s ∈[25.2°,79.2°], the phase angle t of the overflow valve when the oil is replenished e ∈[255.6°,298.8°], in order to satisfy Get the best oil filling start phase angle t s ∈[75.6°,79.2°], the relative high pressure coefficient χ h =0.38, relative low pressure coefficient χ l =0.3, finally take t s =75°, the phase difference between the moving direction of the plunger pump plunger and the moving direction of the two-stage diaphragm head piston is determined as

[0073] The plunger pump structure of the embodiment of the present invention adopts a simplified method of the hydraulic oil leakage gap channel model to quantitatively describe and calculate the leakage of the diaphragm compressor oil chamber, and quantitatively describe and calculate the plunger pump chamber stroke volume through a correction coefficient method, so as to replace the previous method of determining the plunger pump stroke volume by the empirical ratio of the oil chamber volume; the minimum spring force required for the operation of the plunger pump is quantitatively described and calculated considering the friction of the plunger pump sealing ring and the viscous friction of the hydraulic oil, and the selection of the plunger pump spring 4 is optimized; at the same time, with the minimum working pressure of the plunger pump as the optimization goal, the optimal installation phase difference of the plunger pump is quantitatively described and calculated, and the optimal time range for oil filling of the plunger pump and the time to start oil replenishment are determined, which is beneficial to improving the service life of the diaphragm compressor plunger pump and the overall reliability of the diaphragm compressor. The diaphragm compressor plunger pump designed according to the method of the embodiment of the present invention has a simple structure, a small size, is flexible and convenient to use, and is convenient for serial production or customization.

[0074] 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 two-stage opposing piston pump structure diaphragm compressor, characterized in that: The invention comprises a compressor end cover (A), a first-stage plunger pump (B1), a second-stage plunger pump (B2), a plunger pump connecting bolt (C), a first-stage eccentric wheel structure (D1) and a second-stage eccentric wheel structure (D2); the first-stage plunger pump (B1) and the second-stage plunger pump (B2) are respectively installed on the symmetrical sides of the compressor end cover (A) through the plunger pump connecting bolt (C) to achieve dynamic balance; the plunger pump bodies (1) of the first-stage plunger pump (B1) and the second-stage plunger pump (B2) and the compressor end cover (A), and the plunger pump bodies (1 ) and the plunger pump bushing (3), between the plunger pump body (1) and the plunger pump cover (2), and between the plunger pump bushing (3) and the internal plunger pump plunger (5) are all sealed with hydraulic oil by sealing rings; the first-stage plunger pump (B1) and the second-stage plunger pump (B2) are driven by the first-stage eccentric wheel structure (D1) and the second-stage eccentric wheel structure (D2) respectively, and the reaction force of the plunger pump spring (4) and the friction force of the plunger pump plunger (5) jointly realize the process of oil intake, pressurization, oil discharge and pressure reduction of the plunger pump.

2. The two-stage opposing piston pump structure diaphragm compressor according to claim 1 is characterized in that: The plunger pump bodies (1) of the first-stage plunger pump (B1) and the second-stage plunger pump (B2) and the compressor end cover (A) are sealed with hydraulic oil by means of a sealing ring in the fourth sealing groove (14) of the plunger pump body; the plunger pump body (1) and the plunger pump bushing (3) are sealed with hydraulic oil by means of sealing rings in the second sealing groove (12) of the plunger pump body and the third sealing groove (13) of the plunger pump body; the plunger pump cover (2) and the plunger pump body (1) are sealed with hydraulic oil by means of a sealing ring in the first sealing groove (11) of the plunger pump body; and the plunger pump bushing (3) and the plunger pump plunger (5) are sealed with hydraulic oil by means of sealing rings in a plurality of plunger sealing grooves (51).

3. The two-stage opposing piston pump structure diaphragm compressor according to claim 2 is characterized in that: The first-stage plunger pump (B1) and the second-stage plunger pump (B2) are driven by the first-stage eccentric wheel structure (D1) and the second-stage eccentric wheel structure (D2), respectively, so that the plunger pump plunger (5) moves in the compression direction of the plunger pump spring (4). During this process, the volume of the plunger pump oil chamber is reduced, thereby realizing the process of pressurizing and discharging the hydraulic oil in the plunger pump oil chamber. At the same time, the plunger pump spring (4) provides a reaction force to counteract the driving force of the eccentric wheel and the friction force of the plunger pump plunger (5). When the plunger pump plunger (5) moves to the upper dead center position, the plunger pump plunger (5) is driven by the plunger pump spring (4) to counteract the reaction force of the eccentric wheel and the friction force of the plunger pump plunger (5), and pushes the plunger pump plunger (5) to move to the lower dead center. During this process, the volume of the plunger pump oil chamber is increased, thereby realizing the process of decompressing and filling the hydraulic oil in the plunger pump oil chamber until the plunger pump plunger (5) reaches the lower dead center position.

4. The two-stage opposing piston pump structure diaphragm compressor according to claim 2 is characterized in that: The volume chamber volume of the first-stage plunger pump (B1) and the second-stage plunger pump (B2) is larger than the gap L of the diaphragm compressor piston leakage channel. xl The amount of leakage; Diaphragm compressor piston leakage channel clearance L xl The leakage is calculated according to the following formula: In the formula, Q l is the gap L of the diaphragm compressor piston leakage channel xl Leakage flow; d hs is the diameter of the diaphragm compressor piston; δ is the gap L of the diaphragm compressor piston leakage channel xl The gap; μ is the viscosity of the hydraulic oil; l is the gap L of the leakage channel of the diaphragm compressor piston xl Δp is the gap L of the diaphragm compressor piston leakage channel xl The pressure difference on both sides; p oil is the maximum oil pressure of the diaphragm compressor; p air is the atmospheric pressure; m is the number of sealing rings on the diaphragm compressor piston.

5. The two-stage opposing piston pump structure diaphragm compressor according to claim 4 is characterized in that: The volume chamber volumes of the primary plunger pump (B1) and the secondary plunger pump (B2) are calculated according to the following formula: In the formula, m 柱塞 The oil replenishment volume of the primary plunger pump (B1) or the secondary plunger pump (B2); m l is the leakage mass of the gap in the leakage channel of the diaphragm compressor piston; m is the design coefficient, greater than 1; ρ oil is the density of hydraulic oil; d zs L is the diameter of the plunger pump plunger (5); zs is the stroke of the plunger pump plunger (5).

6. The two-stage opposing piston pump structure diaphragm compressor according to claim 1 is characterized in that: The reaction force of the plunger pump spring (4) is calculated according to the following formula: In the formula, F spring,min is the minimum spring force of the plunger pump spring (4) at the bottom dead center position; E is the elastic modulus of the sealing ring in the plunger sealing groove; H is the wire diameter of the sealing ring in the plunger sealing groove; h is the groove depth of the sealing ring in the plunger sealing groove; D is the inner diameter of the sealing ring in the plunger sealing groove; b is the width of the sealing groove in the plunger sealing groove; μ is the Poisson's ratio of the sealing ring in the plunger sealing groove; l is the characteristic length of the plunger pump plunger (5) in the axial direction in contact with the leaking hydraulic oil; ν is the kinematic viscosity of the hydraulic oil; ρ is the density of the hydraulic oil; u is the moving speed of the plunger pump plunger (5); and s is the circumferential clearance of the plunger pump plunger (5).

7. The two-stage opposing piston pump structure diaphragm compressor according to claim 1 is characterized in that: There is a phase difference between the reciprocating motion direction of the diaphragm compressor piston and the reciprocating motion direction of the plunger pump plunger (5), and the phase difference is determined by the pressure values ​​of the relatively high pressure and the relatively low pressure of the diaphragm compressor; the relatively high pressure and the relatively low pressure of the diaphragm compressor are calculated according to the following formula: In the formula, p relative,high is relatively high pressure; h is the relative high pressure coefficient; p oil,max is the maximum oil pressure; l is the relative low pressure coefficient; p stage,1 is the instantaneous oil pressure of the first stage of the diaphragm compressor; p stage,2 is the instantaneous oil pressure of the second stage of the diaphragm compressor; t s is the phase angle of the diaphragm compressor overflow valve oil replenishment start, t e It is the phase angle at which the oil replenishment of the diaphragm compressor relief valve ends.

8. The two-stage opposing piston pump structure diaphragm compressor according to claim 7 is characterized in that: The first-stage plunger pump (B1) and the second-stage plunger pump (B2) are installed symmetrically at 180 degrees, and the relative high pressure coefficient χ h and the relative low pressure coefficient χ l , so that the diaphragm compressor overflow valve oil replenishment start phase angle t s The phase angle t of the diaphragm compressor overflow valve oil supply end e satisfy:

9. The two-stage opposing piston pump structure diaphragm compressor according to claim 8, characterized in that: There is a phase angle between the relative movement direction of the primary plunger pump (B1) and the secondary plunger pump (B2) and the relative movement direction of the piston of the two-stage opposing diaphragm compressor. It meets the following relationship: The first stage of the diaphragm compressor Inhale within the time frame, The best time for the plunger pump to start replenishing oil to the membrane head is [t1,t s ] moment, the best time for the plunger pump to start oiling is [t e ,T]∪[0,t1].

10. A design method for a two-stage opposing piston pump structure diaphragm compressor according to any one of claims 1 to 9, characterized in that: The following steps are involved: Definition of cylinder oil pressure p stage , then the dimensionless oil pressure is described as Here we take the maximum oil pressure p oil,max For the design of nominal discharge pressure for diaphragm compressors, the nominal dimensionless oil pressure is described as The dimensionless oil pressure of the diaphragm compressor is calculated by the thermal process simulation with the crank angle The change curve of the relative high pressure coefficient χ h and the relative low pressure coefficient χ l , so that the diaphragm compressor overflow valve oil replenishment start phase angle t s The phase angle t of the diaphragm compressor overflow valve oil supply end e satisfy: Determine the phase angle between the relative motion direction of the primary plunger pump (B1) and the secondary plunger pump (B2) and the relative motion direction of the piston of the two-stage opposing diaphragm compressor Determine the installation angle range of the primary plunger pump (B1) and the secondary plunger pump (B2).

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