A diaphragm compressor full-process oil replenishment system and design method thereof

Abstract

A full-process oil replenishment system for a diaphragm compressor and a design method thereof, wherein the full-process oil replenishment system includes a plurality of plunger pumps, which are driven by a plunger-driven eccentric wheel. Under the drive, the plurality of plunger pumps replenish oil to the diaphragm head structure of the diaphragm compressor through their respective oil replenishment passages in phases, and the diaphragm head structure overflows excess hydraulic oil through the overflow oil passage; the piston assembly of the diaphragm compressor drives the movement and pressurization of the hydraulic oil in the cylinder of the diaphragm head structure, and the hydraulic oil in the cylinder of the diaphragm head structure leaks outward through the gap leakage oil passage between the diaphragm head structure and the piston assembly; thereby, a dynamic balance of the hydraulic oil quality during the oil replenishment, oil overflow and oil leakage processes of the hydraulic oil in the cylinder of the diaphragm head structure of the diaphragm compressor is achieved. The present invention realizes a more precise oil replenishment operation adapted to the leakage characteristics of the diaphragm compressor by rationally designing the stroke volume of the plunger pump and accurately grasping the oil replenishment timing of the plunger pump during the operation of the diaphragm compressor, thereby optimizing the performance of the plunger pump and the reliability of the diaphragm compressor as a whole.

Description

Technical Field

[0001] The invention belongs to the technical field of diaphragm compressors and relates to a full-process oil replenishing system for a diaphragm compressor and a design method thereof. Background Art

[0002] A diaphragm compressor is a positive displacement compressor that uses a diaphragm to separate the oil and gas sides. Its operating principle is: a motor drives the crankshaft and connecting rod, driving the piston in reciprocating motion, thereby increasing and depressurizing the high-pressure oil. This high-pressure oil then pushes the diaphragm to compress and discharge the gas. Due to their excellent sealing properties and high compression ratio, diaphragm compressors are widely used in the hydrogen energy industry, especially in hydrogen refueling stations. However, issues such as diaphragm life, volumetric efficiency, and diaphragm head strength are critical and difficult issues in the development of diaphragm compressors.

[0003] The oil replenishment, hydraulic, and lubrication systems of a diaphragm compressor directly affect the operational reliability of the entire machine. The hydraulic oil in the diaphragm head structure is driven by the piston driven by the crank-connecting rod mechanism, which not only directly affects the air-side pressure and exhaust volume, but also directly acts on the diaphragm to cause it to flex and deform, and even more directly acts on the diaphragm head structure, affecting its strength and reliability. When the diaphragm compressor is operating, high-pressure hydraulic oil will inevitably leak through the piston ring, which will directly lead to an increase in the clearance of the diaphragm compressor and a decrease in air volume, 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 hydraulic oil in the diaphragm head. The oil replenishment plunger pump is generally driven by the crankshaft eccentric wheel, and forms a certain phase difference with the operation of the piston in the crankcase to replenish the oil. Traditional diaphragm compressors generally set 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 Chinese patent with publication number CN109469603B proposes "a high-pressure diaphragm compressor, its oil replenishment system and oil replenishment method". By adding a relief valve passage between the oil replenishment plunger pump and the oil replenishment check valve, the oil replenishment pressure of the diaphragm compressor during the suction stroke or exhaust stroke is controlled, thereby realizing the regulation of the oil replenishment amount of the plunger pump.

[0004] In the oil replenishment system, the plunger pump stroke volume is generally designed to be greater than the leakage of hydraulic oil in the cylinder. However, excessive plunger pump will affect the suction volume, resulting in insufficient suction volume per turn. How to reasonably set the plunger pump stroke volume, that is, to control the oil replenishment volume, is one of the key issues to ensure the stable operation of the diaphragm compressor, and it is also a difficult problem in the current diaphragm compressor design stage. However, because the actual leakage of the diaphragm compressor plunger pump is difficult to accurately measure, the plunger pump stroke volume selection in the previous design stage often uses an empirical value relative to the oil chamber volume ratio, and the actual oil replenishment phase angle is less than 180°. In general diaphragm compressor design technology, since a single plunger pump can only replenish oil into the diaphragm head cylinder from the bottom dead center to the top dead center of the plunger, in fact, the leakage of hydraulic oil in the diaphragm compressor and the generation of bubbles in the cylinder occur throughout the entire process. The traditional single plunger pump structure cannot achieve oil replenishment that adapts to the oil pressure and leakage characteristics in the diaphragm compressor cavity throughout the entire process. Summary of the Invention

[0005] The purpose of the present invention is to address the problems in the above-mentioned prior art and provide a full-process oil replenishment system for a diaphragm compressor and a design method thereof. By reasonably designing the stroke volume of the plunger pump and accurately grasping the timing of the plunger pump oil replenishment during the operation of the diaphragm compressor, a more precise oil replenishment operation can be achieved by adapting to the leakage characteristics of the diaphragm compressor, thereby optimizing the performance of the plunger pump and the reliability of the diaphragm compressor as a whole.

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

[0007] On the first aspect, a full-process oil replenishment system for a diaphragm compressor is proposed, including multiple plunger pumps, which are driven by a plunger-driven eccentric wheel. Under the drive, the multiple plunger pumps replenish oil to the diaphragm head structure of the diaphragm compressor through their respective oil replenishment passages in phases, and the diaphragm head structure overflows excess hydraulic oil through the overflow oil passage; the piston assembly of the diaphragm compressor drives the movement and pressurization of the hydraulic oil in the cylinder of the diaphragm head structure, and the hydraulic oil in the cylinder of the diaphragm head structure leaks outward through the gap leakage oil passage between the diaphragm head structure and the piston assembly; thereby, the dynamic balance of the hydraulic oil quality in the oil replenishment, oil overflow and oil leakage processes of the hydraulic oil in the cylinder of the diaphragm head structure of the diaphragm compressor is achieved.

[0008] As a preferred solution, the plunger pump consists of a first plunger pump and a second plunger pump, the installation phase angle between the first plunger pump and the second plunger pump is 180°, the first plunger pump and the second plunger pump are symmetrically arranged on both sides of the plunger drive eccentric wheel, and the first plunger pump and the second plunger pump replenish oil to the diaphragm head structure of the diaphragm compressor through the first oil supply oil circuit and the second oil supply oil circuit in phases respectively.

[0009] As a preferred solution, the plunger movement mode of the first plunger pump conforms to the following expression:

[0010]

[0011] Where x zs is the plunger displacement of the first plunger pump; r is the radius of the plunger-driven eccentric wheel; θ is the rotation angle of the plunger-driven eccentric wheel; a is the eccentric distance of the plunger-driven eccentric wheel; v zs is the plunger speed of the first plunger pump.

[0012] As a preferred solution, the gap leakage oil path between the diaphragm head structure and the piston assembly is a gap channel between the cylinder liner and the piston;

[0013] The hydraulic oil leakage amount of the gap leakage oil circuit meets the following expression:

[0014] m L3 =f(p oil )

[0015] Where m L3 is the hydraulic oil leakage of the gap leakage oil circuit; p oil It is the oil pressure in the cylinder of the diaphragm head structure.

[0016] As a preferred solution, the oil pressure and air pressure in the cylinder of the diaphragm head structure of the diaphragm compressor change synchronously within a period T. During the time, the membrane head structure performs the suction process. During this time, the membrane head structure performs the exhaust process.

[0017] As a preferred solution, the first plunger pump and the second plunger pump are respectively operated when the pressure in the membrane head structure cylinder is lower than the defined relative pressure p relative During operation and above the defined relative pressure p relative During the operation, the oil is replenished, and the installation phase angle of the first plunger pump and the second plunger pump is set to 180°. The phase angle of the plunger movement of the first plunger pump and the movement of the membrane head structure is set to

[0018] Calculate using the following formula:

[0019]

[0020] Where, is the crank angle corresponding to different cylinder pressure moments of the membrane head structure within one cycle; The pressure inside the membrane head structure cylinder during the intake phase is equal to the defined relative pressure p relative The crank angle at The pressure inside the membrane head structure cylinder during the exhaust phase is equal to the defined relative pressure p relative The crank angle at

[0021] Define relative pressure p relativeCalculate using the following formula:

[0022] p relative =χ h p oil,max

[0023] Where, X h is the relative pressure coefficient; p oil,max It is the maximum oil pressure in the cylinder of the diaphragm head structure.

[0024] As a preferred solution, the pump chamber volumes of the first plunger pump and the second plunger pump are calculated by the following formula:

[0025]

[0026] Where V zs is the pump chamber volume; m is the design coefficient;

[0027] By partitioning the oil replenishment time of the first plunger pump and the second plunger pump, the pump chamber volumes of the first plunger pump and the second plunger pump are determined, and then the design parameters of the first plunger pump and the second plunger pump are determined.

[0028] As a preferred solution, the plunger pump consists of a first plunger pump, a second plunger pump and a third plunger pump. The installation phase angle between the first plunger pump, the second plunger pump and the third plunger pump is 120°. Under the action of the plunger driving eccentric wheel, the first plunger pump, the second plunger pump and the third plunger pump successively perform the oil replenishing process.

[0029] As a preferred solution, the theoretical oil filling time t of the first plunger pump is ll for:

[0030]

[0031] The actual oil replenishment time t of the first plunger pump sj The following expression is met:

[0032]

[0033] Where p zs is the hydraulic oil pressure of the plunger pump; p oil It is the hydraulic oil pressure in the cylinder of the diaphragm head structure.

[0034] Secondly, a design method for a full-process oil replenishment system for a diaphragm compressor is proposed, comprising the following steps:

[0035] The variation of the pressure in the diaphragm compressor cavity with the crank angle is solved through the thermal calculation process, and the corresponding oil replenishment phase areas of multiple plunger pumps are obtained;

[0036] Define p oil is the oil pressure in the cylinder of the diaphragm head structure, and the dimensionless oil pressure is Here, the maximum oil pressure p in the cylinder of the membrane head structure is taken oil,max Design the nominal discharge pressure for the diaphragm compressor, and the nominal dimensionless oil pressure is The dimensionless pressure variation curve of the diaphragm compressor with the crank angle is obtained through simulation calculation, and the corresponding oil replenishment starting point of each plunger pump is obtained;

[0037] Obtain the leakage of multiple plunger pumps corresponding to different oil-feeding phase zones, design the diameter and stroke size of each plunger pump, and obtain the structure of each plunger pump;

[0038] According to the structure of each plunger pump, the appropriate ball bearing is selected to design the plunger drive eccentric wheel structure, thereby completing the determination of the plunger pump oil replenishment phase angle and the design of the plunger pump, forming a full-process oil replenishment system for the diaphragm compressor.

[0039] Compared with the prior art, the present invention has at least the following beneficial effects:

[0040] By using multiple plunger pumps driven by a plunger-driven eccentric wheel, the oil pressure in the diaphragm compressor cavity is adapted during the entire process of intake, compression, and exhaust of the diaphragm compressor's membrane head structure, and oil replenishment is performed throughout the entire operation process of the diaphragm compressor. By rationally dividing different pressure intervals or oil replenishment intervals, multiple plunger pumps can be used for time-divided and segmented oil replenishment. By rationally arranging the plunger pump cavity volume, the matching accuracy of the oil injection volume and leakage volume is higher, and accurate full-process oil replenishment operation adapted to different pressure intervals in the diaphragm compressor cavity is performed. The actual plunger pump oil replenishment time is less than the movement time of the plunger from the bottom dead center to the top dead center. The oil replenishment pump structure composed of multiple plunger pumps can achieve full-process oil replenishment of the diaphragm compressor within one cycle without any oil replenishment time gap. The present invention uses multiple plunger pumps to replenish oil in the oil chamber of the diaphragm compressor according to pressure intervals, working stages, and time periods. This overcomes the problem of inaccurate grasp of the timing and amount of oil replenishment in the research and development and design stages of traditional diaphragm compressors, and enables the amount of oil replenishment to adapt to the leakage characteristics of the diaphragm compressor and match the changing characteristics of the pressure in the diaphragm compressor cavity, so as to perform more accurate oil replenishment throughout the entire process. This achieves a dynamic balance of the hydraulic oil quality during the replenishment, overflow, and leakage processes of the hydraulic oil in the cylinder of the diaphragm head structure of the diaphragm compressor, optimizes the performance of the plunger pump, and improves the overall reliability of the diaphragm compressor. During the actual debugging of the diaphragm compressor, the amount of oil replenishment in each stage can also be flexibly adjusted according to actual needs, thereby improving the overall design flexibility of the diaphragm compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 Schematic diagram of the full-process oil replenishment system of a diaphragm compressor with a double-piston pump structure at a 180° phase angle according to an embodiment of the present invention;

[0043] Figure 2 This is a graph showing the displacement and velocity of the plunger in a single plunger pump according to an embodiment of the present invention;

[0044] Figure 3 Schematic diagram of the oil leakage path structure between the cylinder liner and the piston according to an embodiment of the present invention;

[0045] Figure 4 Schematic diagram of oil pressure changes in the cylinder of a diaphragm compressor according to an embodiment of the present invention;

[0046] Figure 5 Schematic diagram of dimensionless oil pressure variation in the cylinder of a single-stage double-piston diaphragm compressor according to an embodiment of the present invention;

[0047] Figure 6 Schematic diagram of the whole process oil replenishment system of the diaphragm compressor with a three-plunger pump structure with a 120° phase angle according to an embodiment of the present invention;

[0048] Figure 7 Schematic diagram of dimensionless oil pressure variation in the cylinder of a single-stage three-plunger diaphragm compressor according to an embodiment of the present invention;

[0049] In the accompanying drawings: 11-first plunger pump; 12-second plunger pump; 13-third plunger pump; 2-plunger drive eccentric wheel; 3-diaphragm head structure; 4-piston assembly; G1-cylinder liner; G2-piston; L11-first oil supply circuit; L12-second oil supply circuit; L13-third oil supply circuit; L2-overflow oil circuit; L3-gap leakage oil circuit. DETAILED DESCRIPTION

[0050] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] An embodiment of the present invention proposes a full-process oil replenishment system for a diaphragm compressor, the main structure of which includes multiple plunger pumps, which are driven by a plunger-driven eccentric wheel 2. Under the drive, the multiple plunger pumps replenish oil to the diaphragm head structure 3 of the diaphragm compressor through their respective oil replenishment passages in phases, and the diaphragm head structure 3 overflows excess hydraulic oil through the overflow oil passage L2; the piston assembly 4 of the diaphragm compressor drives the movement and pressurization of the hydraulic oil in the cylinder of the diaphragm head structure 3, and the hydraulic oil in the cylinder of the diaphragm head structure 3 leaks outward through the gap leakage oil passage L3 between the diaphragm head structure 3 and the piston assembly 4; thereby, the dynamic balance of the hydraulic oil quality in the oil replenishment, overflow and leakage processes of the hydraulic oil in the cylinder of the diaphragm head structure 3 of the diaphragm compressor is achieved.

[0052] Example 1

[0053] like Figure 1 As shown, the full-process oil replenishment system of the diaphragm compressor according to the embodiment of the present invention includes: a first plunger pump 11 , a second plunger pump 12 , a plunger drive eccentric wheel 2 , a diaphragm head structure 3 and a piston assembly 4 .

[0054] The first plunger pump 11 and the second plunger pump 12 are symmetrically placed on either side of the plunger-driven eccentric wheel 2. They replenish oil to the diaphragm head structure 3 through the first oil replenishment line L11 and the second oil replenishment line L12 in phases. The diaphragm head structure 3 overflows excess hydraulic oil through the overflow oil line L2. The piston assembly 4 drives the hydraulic oil in the cylinder of the diaphragm head structure 3 to move and increase the pressure. The hydraulic oil in the cylinder of the diaphragm head structure 3 leaks outward through the leakage oil line L3 between the diaphragm head structure 3 and the piston assembly 4. In this way, the dynamic balance of the hydraulic oil quality of the replenishment, overflow, and leakage of the hydraulic oil in the cylinder of the diaphragm head structure 3 of the diaphragm compressor is achieved.

[0055] Furthermore, the movement of the plunger of the first plunger pump 11 can be described by the following formula:

[0056]

[0057] Where: x zs - the plunger displacement of the first plunger pump 11, in m; r - the radius of the plunger drive eccentric 2, in m; θ - the rotation angle of the plunger drive eccentric 2, in rad; a - the eccentricity of the plunger pump drive eccentric 2, in m; v zs - Speed ​​of the plunger of the first plunger pump 11, in m·s -1 .

[0058] like Figure 2 As shown, the oil filling speed of the plunger pump is different at different times during the movement process. Taking the first plunger pump 11 as an example, the movement is started and the timing is performed with its plunger at the bottom dead center position. At time t1, the plunger reaches the top dead center position, and at time T, the plunger reaches the bottom dead center position again. During the movement of the plunger from the bottom dead center to the top dead center, the first plunger pump 11 has the highest speed at time t1, so the plunger pump plunger's oil replenishment speed is the fastest at this time. The same is true at time t2, and the same is true for the second plunger pump 12. t1 is the time of maximum speed during the movement of the plunger pump plunger from the bottom dead center to the top dead center, measured in seconds; t2 is the time of maximum speed during the movement of the plunger pump plunger from the top dead center to the bottom dead center, measured in seconds.

[0059] like Figure 3 As shown, the gap leakage oil path L3 between the diaphragm head structure 3 and the piston assembly 4 is the gap channel between the cylinder liner G1 and the piston G2. The hydraulic oil leakage can be described as:

[0060] m L3 =f(p oil )

[0061] Where: m L3 - Hydraulic oil leakage from gap leakage oil circuit L3, in kg·s -1 ;p oil -The oil pressure in the cylinder of the diaphragm head structure 3, in Pa.

[0062] Further, such as Figure 4 As shown in the figure, the oil pressure and air pressure in the cavity of the diaphragm compressor diaphragm head structure 3 change synchronously within a period T. During the time, the diaphragm compressor membrane head structure 3 performs the suction process. During this time, the diaphragm compressor diaphragm head structure 3 performs the exhaust process. In order to separately describe the relatively high pressure stage and the relatively low pressure stage in the cavity during the operation of the diaphragm compressor, the relative pressure in the cavity of the diaphragm compressor diaphragm head structure 3 is defined as follows:

[0063] p relative =χ h p oil,max

[0064] Where: p relative -Define relative pressure, unit is Pa; X h -Relative pressure coefficient, recommended to be 0.2 to 0.6; p oil,max -The maximum oil pressure in the cylinder of the diaphragm compressor diaphragm head structure 3, in Pa.

[0065] Optionally, the first plunger pump 11 and the second plunger pump 12 replenish oil during the intake process and exhaust process of the diaphragm head structure 3 of the diaphragm compressor, respectively. Therefore, the installation phase angle of the first plunger pump 11 and the second plunger pump 12 is set to 180°, and the phase angle of the plunger movement of the first plunger pump 11 and the movement of the piston assembly 4 is set to 0. In this way, when the first plunger pump 11 is in the oil replenishment stage and the second plunger pump 12 is in the oil intake stage, the diaphragm head structure 3 is undergoing the complete process of the suction stage; when the first plunger pump 11 is in the oil intake stage and the second plunger pump 12 is in the oil replenishment stage, the diaphragm head structure 3 is undergoing the complete process of the compression and exhaust stages; thereby, the dual plunger pump structures 11 and 12 replenish oil throughout the entire process of the intake, compression and exhaust stages of the diaphragm head structure 3 of the diaphragm compressor.

[0066] Optionally, the first plunger pump 11 and the second plunger pump 12 are respectively in the membrane head structure 3 cylinder pressure is lower than the defined relative pressure p relative During operation and above the defined relative pressure p relative During the operation, the oil is replenished, and the installation phase angle of the first plunger pump 11 and the second plunger pump 12 is set to 180 degrees. The phase angle of the plunger movement of the first plunger pump 11 and the movement of the membrane head structure 3 is set to pass Figure 4 The initial moment definition is, It can be calculated and described by the following formula:

[0067]

[0068] Where: -The crank angle corresponding to different cylinder pressures of the membrane head structure 3 within one cycle, in rad;

[0069] - During the intake phase, the pressure inside the membrane head structure 3 cylinder is equal to the defined relative pressure p relative The crank angle at time , in rad; - During the exhaust phase, the pressure in the cylinder of the membrane head structure 3 is equal to the defined relative pressure p relative The crank angle at time , in rad.

[0070] Specifically, when the oil pressure in the cylinder of the diaphragm head structure 3 of the diaphragm compressor is higher than the defined relative pressure, the first plunger pump 11 is in the oil replenishment stage and the second plunger pump 12 is in the oil intake stage; when the oil pressure in the cylinder of the diaphragm head structure 3 of the diaphragm compressor is lower than the defined relative pressure, the first plunger pump 11 is in the oil intake stage and the second plunger pump 12 is in the oil replenishment stage; thereby, the dual plunger pump structure realizes oil replenishment throughout the entire process when the diaphragm head structure 3 of the diaphragm compressor is higher than the defined relative pressure and lower than the defined relative pressure.

[0071] Furthermore, the pump chamber volume of the double-piston pump structure can be described by the following formula:

[0072]

[0073] Where: V zs - Pump chamber volume, in m 3 ;X m -Design coefficient, greater than 1, recommended range is 1.2 to 3.

[0074] Furthermore, the above method can be used to partition the oil replenishment time of the first plunger pump 11 and the second plunger pump 12, determine the pump chamber volume of the first plunger pump 11 and the second plunger pump 12, and then determine their basic design parameters.

[0075] Through the above method, the opposing double-piston pump is designed during the development and research of a new single-stage double-piston diaphragm compressor. The specific steps are as follows:

[0076] Step 1: Through the thermal calculation process, the pressure inside the diaphragm compressor cavity is solved as the crank angle changes, and the relative pressure coefficient X is taken. h =0.5, and the oil replenishment phase region of the first plunger pump 11 and the second plunger pump 12 is obtained.

[0077] like Figure 5 As shown, define p oil is the oil pressure in the cylinder of the membrane head structure 3, and the dimensionless oil pressure is Here, the maximum oil pressure p in the cylinder of the membrane head structure 3 is taken oil,max Design the nominal discharge pressure for the diaphragm compressor, and the nominal dimensionless oil pressure is The curve of the dimensionless pressure of the diaphragm compressor changing with the crank angle is obtained by AMESim simulation calculation. The dimensionless oil pressure on the vertical axis is equal to the relative pressure coefficient X. h , the intersection points are A and B, A is taken as the starting point of oil replenishment of the low-pressure first plunger pump 11, and B is taken as the starting point of oil replenishment of the high-pressure second plunger pump 12, that is, the first plunger pump 11 is set at the phase angle Start replenishing oil when the second plunger pump 12 is set at the phase angle Start refueling.

[0078] Step 2: The leakage amount of different oil replenishment phase areas is solved by the above-mentioned leakage hydraulic oil calculation method, and the plunger pump diameter and stroke size are designed. In the design, the design stroke of the first plunger pump 11 and the second plunger pump 12 are ensured to be the same. The design coefficient X is taken. m ≈2, and the solution is that the diameter of the first plunger pump 11 is 10 mm and the stroke is 8 mm, and the diameter of the second plunger pump 12 is 18 mm and the stroke is 8 mm. The plunger pump structure can be designed accordingly.

[0079] Step 3: Select appropriate ball bearings and design the eccentric wheel 2 structure according to the structure of the first plunger pump 11 and the structure of the second plunger pump 12, thereby completing the determination of the plunger pump oil replenishment phase angle and the design of the plunger pump.

[0080] The single-stage diaphragm compressor full-process dual-plunger pump oil replenishment method described in this embodiment can realize low-pressure oil replenishment and high-pressure oil replenishment in separate phase zones. The high-pressure oil replenishment, that is, the second plunger pump 12 oil replenishment phase zone is located at a high compression and exhaust pressure, the leakage at the piston is large, and the pressure variation range is large, and bubbles are easily generated in the oil chamber. Therefore, the second plunger pump 12 is suitable for a larger volume chamber. The low-pressure oil replenishment, that is, the first plunger pump 11 oil replenishment phase zone is located at a low suction and compression pressure, and the leakage at the piston is small. The smaller first plunger pump 11 oil replenishment can avoid the diaphragm compressor from having an oil shortage condition and reduce the influence of the plunger pump oil replenishment on the suction volume. Therefore, this embodiment realizes the full-process dual-plunger pump pressure phase zone oil replenishment.

[0081] Example 2

[0082] like Figure 6 As shown, the full-process oil replenishment system of the diaphragm compressor according to the embodiment of the present invention includes: a first plunger pump 11, a second plunger pump 12, a third plunger pump 13, a plunger drive eccentric wheel 2, a diaphragm head structure 3 and a piston assembly 4.

[0083] Specifically, such as Figure 6 As shown, compared with Example 1, the full-process oil replenishment system for the diaphragm compressor described in this embodiment is implemented by installing three plunger pumps installed at a phase angle of 120° and evenly distributed. Under the action of the plunger-driven eccentric wheel 2, the first plunger pump 11, the second plunger pump 12, and the third plunger pump 13 successively perform the oil replenishment process. The diaphragm head structure 3 of the diaphragm compressor overflows oil through the oil overflow passage L2, and the hydraulic oil in the leakage cavity leaks out through the leakage passage L3 between the piston assembly 4 and the diaphragm head structure 3, causing external leakage. In this way, the dynamic balance process of the hydraulic oil mass of the hydraulic oil in the cylinder of the diaphragm head structure 3 of the diaphragm compressor is achieved, including oil replenishment, oil overflow, and oil leakage.

[0084] Furthermore, compared with Example 1, the three-plunger oil charge pump structure of this embodiment can adapt to the pressure changes during the intake, exhaust and compression processes of the diaphragm compressor to perform leakage oil charge operations more accurately. By reasonably arranging the volume of the plunger pump cavity, the matching accuracy of the oil injection amount and the leakage amount can be higher. The design coefficient X in the selection of the pump cavity volume is m It can be smaller, and 1.1 to 2 is recommended.

[0085] Specifically, the theoretical oil replenishment time t of the first plunger pump 11 is ll It can be described as:

[0086]

[0087] Specifically, the actual oil replenishment time t of the first plunger pump 11 is sj It can be described as:

[0088]

[0089] Where: p zs - the hydraulic oil pressure of the first plunger pump 11, in Pa; oil -Hydraulic oil pressure in the cylinder of the membrane head structure 3, in Pa.

[0090] The actual oil replenishment time of the plunger pump 11 is less than the movement time of the plunger from the bottom dead center to the top dead center. The three-plunger pump oil replenishment pump structure can realize the full process oil replenishment without oil replenishment time gap within one cycle of the diaphragm compressor.

[0091] Similarly, using the aforementioned method, a three-plunger pump with a 120° phase angle is designed during the development of a new single-stage three-plunger diaphragm compressor. The specific steps are as follows:

[0092] The first step: Through the thermal calculation process, the variation of the pressure in the diaphragm compressor cavity with the crank angle is solved. The oil replenishment phase area is divided into the oil replenishment phase area of ​​the first plunger pump 11, the second plunger pump 12 and the third plunger pump 13 at the end of exhaust and the crank angle of 180°.

[0093] like Figure 7 As shown, we also define p oil is the oil pressure in the cylinder of the membrane head structure 3, and the dimensionless oil pressure is Here, the maximum oil pressure p in the cylinder of the membrane head structure 3 is taken oil,max Design the nominal discharge pressure for the diaphragm compressor, and the nominal dimensionless oil pressure is =1, the dimensionless pressure of the diaphragm compressor is calculated by AMESim simulation to obtain the change curve of the crank angle, and the corresponding moment of crank angle B is defined as the starting point of the first plunger pump 11 to replenish oil, the corresponding moment of crank angle C is defined as the starting point of the second plunger pump 12 to replenish oil, and the corresponding moment of crank angle A is defined as the starting point of the third plunger pump 12 to replenish oil, that is, the first plunger pump 11 is at The crank angle starts to replenish oil, and the second plunger pump 12 is The crank angle starts to replenish oil, and the third plunger pump is Start adding oil at the crank angle.

[0094] Step 2: The leakage amount of different oil replenishment phase areas is solved by the above-mentioned leakage hydraulic oil calculation method, and the plunger pump diameter and stroke size are designed. In the design, the design strokes of the first plunger pump 11, the second plunger pump 12 and the third plunger pump 13 are ensured to be the same. Since the strokes of the three plunger pumps have overlapping phase areas, the modified design coefficient is taken. The solution is that the diameter of the first plunger pump 11 is 13 mm and the stroke is 8 mm, the diameter of the second plunger pump 12 is 13 mm and the stroke is 8 mm, and the diameter of the third plunger pump 13 is 6.5 and the stroke is 8 mm. The plunger pump structure can be designed based on this.

[0095] Step 3: Select appropriate ball bearings and design the eccentric wheel 2 structure according to the structure of the first plunger pump 11, the second plunger pump 12 and the third plunger pump 13, thereby completing the determination of the plunger pump oil replenishment phase angle and the design of the plunger pump.

[0096] The three-plunger pump oil replenishment method for the single-stage diaphragm compressor throughout the entire process described in this embodiment can realize oil replenishment in the suction and compression low-pressure phase zone, oil replenishment in the compression and exhaust high-pressure phase zone, and oil replenishment in the suction and expansion high-pressure phase zone, and realize the whole process in stages and phase zones. According to the oil replenishment quantity requirements at different stages, the first plunger pump oil replenishment phase zone is located in the low-pressure zone of the oil chamber, and the pressure variation range in the oil cylinder is relatively small, while the second plunger pump oil replenishment phase zone and the third plunger pump oil replenishment phase zone are located in the high-pressure zone, and the pressure variation range in the oil cylinder is relatively large. The plunger pump with a larger volume cavity is used to replenish oil in the phase interval with a large pressure variation range, which can effectively avoid the generation of bubbles in the oil chamber and improve the overall performance of the diaphragm compressor. The appropriate amount of plunger pump oil replenishment in the low-pressure zone also avoids the occurrence of oil shortage in the diaphragm compressor. In the actual diaphragm compressor debugging process, the oil replenishment quantity in each stage can be flexibly adjusted according to actual needs, thereby improving the overall design flexibility of the diaphragm compressor.

[0097] The present invention can achieve more accurate oil replenishment operation adapted to the leakage characteristics of the diaphragm compressor during its normal operation, overcome the problem of inaccurate grasp of the timing and amount of oil replenishment of the plunger pump in the previous diaphragm compressor research and development and design stage, and optimize the performance of the plunger pump and the overall reliability of the diaphragm compressor.

[0098] Although the present application has been 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 herein within the principles and scope of the present application. The scope of protection of the present application is determined by the appended claims, and the claims are intended to cover all modifications encompassed by the literal meaning or scope of equivalents of the technical features in the claims.

Claims

1. A full-process oil replenishment system for a diaphragm compressor, characterized by: The invention comprises a plurality of plunger pumps, which are driven by a plunger-driven eccentric wheel (2). Under the drive, the plurality of plunger pumps replenish oil to the diaphragm head structure (3) of the diaphragm compressor through their respective oil replenishment passages in phases, and the diaphragm head structure (3) overflows excess hydraulic oil to the outside through the oil overflow oil passage (L2); the piston assembly (4) of the diaphragm compressor drives the hydraulic oil in the cylinder of the diaphragm head structure (3) to move and increase the pressure, and the hydraulic oil in the cylinder of the diaphragm head structure (3) leaks to the outside through the gap leakage oil passage (L3) between the diaphragm head structure (3) and the piston assembly (4); thereby, the dynamic balance of the hydraulic oil quality in the oil replenishment, oil overflow and oil leakage processes of the hydraulic oil in the cylinder of the diaphragm head structure (3) of the diaphragm compressor is achieved; The plunger pump is composed of a first plunger pump (11) and a second plunger pump (12), the installation phase angle between the first plunger pump (11) and the second plunger pump (12) is 180 degrees, the first plunger pump (11) and the second plunger pump (12) are symmetrically arranged on both sides of the plunger drive eccentric wheel (2), and the first plunger pump (11) and the second plunger pump (12) respectively replenish oil to the diaphragm head structure (3) of the diaphragm compressor through the first oil replenishment oil circuit (L11) and the second oil replenishment oil circuit (L12) in phases; The first plunger pump (11) and the second plunger pump (12) are respectively operated when the pressure in the cylinder of the membrane head structure (3) is lower than the defined relative pressure p relative During operation and above the defined relative pressure p relative During the operation, the oil is replenished, and the installation phase angle of the first plunger pump (11) and the second plunger pump (12) is set to 180 degrees, and the phase angle of the plunger movement of the first plunger pump (11) and the movement of the membrane head structure (3) is set to Calculate using the following formula: Where, is the crank angle corresponding to different cylinder pressure moments of the membrane head structure (3) within one cycle; The pressure in the cylinder of the membrane head structure (3) during the intake phase is equal to the defined relative pressure p relative The crank angle at The pressure in the cylinder of the membrane head structure (3) during the exhaust phase is equal to the defined relative pressure p relative The crank angle at Define relative pressure p relative Calculate using the following formula: p relative =x h p oil,max Where, χ h is the relative pressure coefficient; p oil,max is the maximum oil pressure in the cylinder of the membrane head structure (3); The pump chamber volumes of the first plunger pump (11) and the second plunger pump (12) are calculated using the following formula: Where V zs is the pump chamber volume; m is the design coefficient; m L3 is the hydraulic oil leakage amount of the gap leakage oil circuit (L3); By partitioning the oil replenishment time of the first plunger pump (11) and the second plunger pump (12), the pump chamber volumes of the first plunger pump (11) and the second plunger pump (12) are determined, thereby determining the design parameters of the first plunger pump (11) and the second plunger pump (12); Alternatively, the plunger pump is composed of a first plunger pump (11), a second plunger pump (12) and a third plunger pump (13), wherein the installation phase angle between the first plunger pump (11), the second plunger pump (12) and the third plunger pump (13) is 120 degrees, and under the action of the plunger driving eccentric wheel (2), the first plunger pump (11), the second plunger pump (12) and the third plunger pump (13) successively perform the oil replenishing process; The variation of the pressure in the diaphragm compressor cavity with the crank angle is obtained by solving the thermal calculation process, and the oil replenishment phase region of the first plunger pump (11), the second plunger pump (12) and the third plunger pump (13) is obtained by taking the exhaust end time and the crank angle of 180° as the demarcation point of the oil replenishment phase region; Define p oil is the oil pressure in the cylinder of the diaphragm head structure (3), and the dimensionless oil pressure is Here we take the maximum oil pressure p in the cylinder of the membrane head structure (3) oil,max Design the nominal discharge pressure for the diaphragm compressor, and the nominal dimensionless oil pressure is The curve of the dimensionless pressure of the diaphragm compressor changing with the crank angle is obtained by AMESim simulation calculation. The corresponding moment of crank angle B is defined as the starting point of the first plunger pump (11) to replenish oil, the corresponding moment of crank angle C is defined as the starting point of the second plunger pump (12) to replenish oil, and the corresponding moment of crank angle A is defined as the starting point of the third plunger pump (13) to replenish oil. That is, the first plunger pump (11) is at The second plunger pump (12) starts to replenish oil at the crank angle. The third plunger pump (13) starts to replenish oil at the crank angle. Start adding oil at the crank angle; The leakage amount of different oil replenishment phase areas is obtained by calculating the hydraulic oil leakage amount, and the plunger pump diameter and stroke size are designed. In the design, the design strokes of the first plunger pump (11), the second plunger pump (12) and the third plunger pump (13) are ensured to be the same. Since the strokes of the three plunger pumps have overlapping phase areas, a correction design coefficient is taken. The diameters and strokes of the first plunger pump (11), the second plunger pump (12) and the third plunger pump (13) are obtained, and the plunger pump structures are designed accordingly; According to the structure of the first plunger pump (11), the second plunger pump (12) and the third plunger pump (13), the ball bearing is selected to design the eccentric wheel (2) structure, thereby completing the determination of the plunger pump oil replenishment phase angle and the design of the plunger pump.

2. The diaphragm compressor full-process oil replenishment system according to claim 1, characterized in that: The plunger movement mode of the first plunger pump (11) conforms to the following expression: Where x zs is the plunger displacement of the first plunger pump (11); r is the radius of the plunger-driven eccentric (2); θ is the rotation angle of the plunger-driven eccentric wheel (2); a is the eccentric distance of the plunger-driven eccentric wheel (2); v zs is the plunger speed of the first plunger pump (11).

3. The full-process oil replenishment system for a diaphragm compressor according to claim 2, characterized in that: The gap leakage oil path (L3) between the diaphragm head structure (3) and the piston assembly (4) is a gap channel between the cylinder sleeve (G1) and the piston (G2); The hydraulic oil leakage amount of the gap leakage oil circuit (L3) conforms to the following expression: m L3 =f(p oil ) Where m L3 is the hydraulic oil leakage of the gap leakage oil circuit (L3); p oil is the oil pressure in the cylinder of the diaphragm head structure (3).

4. The full-process oil replenishment system for a diaphragm compressor according to claim 3, characterized in that: The oil pressure and gas pressure in the cylinder of the diaphragm compressor's diaphragm head structure (3) change synchronously within a period T. During the time, the membrane head structure (3) performs the suction process. During the time, the membrane head structure (3) performs the exhaust process.

5. The full-process oil replenishment system for a diaphragm compressor according to claim 4, characterized in that: The theoretical oil replenishment time t of the first plunger pump (11) ll for: The actual oil replenishment time t of the first plunger pump (11) sj The following expression is met: Where p zs is the hydraulic oil pressure of the plunger pump; p oil is the hydraulic oil pressure in the cylinder of the membrane head structure (3).

6. A design method for a full-process oil replenishment system for a diaphragm compressor according to any one of claims 1 to 5, characterized in that: The following steps are involved: The variation of the pressure in the diaphragm compressor cavity with the crank angle is solved through the thermal calculation process, and the corresponding oil replenishment phase areas of multiple plunger pumps are obtained; Define p oil is the oil pressure in the cylinder of the diaphragm head structure (3), and the dimensionless oil pressure is Here we take the maximum oil pressure p in the cylinder of the membrane head structure (3) oil,max Design the nominal discharge pressure for the diaphragm compressor, and the nominal dimensionless oil pressure is The dimensionless pressure variation curve of the diaphragm compressor with the crank angle is obtained through simulation calculation, and the corresponding oil replenishment starting point of each plunger pump is obtained; Obtain the leakage of multiple plunger pumps corresponding to different oil-feeding phase zones, design the diameter and stroke size of each plunger pump, and obtain the structure of each plunger pump; According to the structure of each plunger pump, a suitable ball bearing is selected to design the plunger drive eccentric wheel (2) structure, thereby completing the determination of the plunger pump oil replenishment phase angle and the design of the plunger pump, and forming a full-process oil replenishment system for the diaphragm compressor.

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