Whole-process oil supplementing system of diaphragm compressor and design method of whole-process oil supplementing system

Abstract

According to the whole-process oil supplementing system of the diaphragm compressor and the design method of the whole-process oil supplementing system, the whole-process oil supplementing system comprises a plurality of plunger pumps, the plunger pumps are driven by a plunger driving eccentric wheel, and the plunger pumps are driven to supplement oil to a diaphragm head structure of the diaphragm compressor in different phases through respective oil supplementing channels; the membrane head structure overflows redundant hydraulic oil through the oil overflow path; a piston assembly of the diaphragm compressor drives in-cylinder hydraulic oil of a diaphragm head structure to move and pressurize, and the in-cylinder hydraulic oil of the diaphragm head structure leaks outwards through a gap leakage oil way between the diaphragm head structure and the piston assembly; therefore, hydraulic oil mass dynamic balance in the oil supplementing, oil overflowing and oil leaking processes of hydraulic oil in the membrane head structure cylinder of the membrane compressor is achieved. The stroke volume of the plunger pump is reasonably designed, the oil supplementing time of the plunger pump is accurately mastered in the running process of the diaphragm compressor, more accurate oil supplementing operation adaptive to the leakage characteristics of the diaphragm compressor is achieved, and the performance of the plunger pump and the overall reliability of the diaphragm compressor are optimized.

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 side and the gas side. Its working principle is: the motor drives the crankshaft connecting rod to drive the piston to reciprocate, thereby increasing and releasing the pressure of the high-pressure oil, and then the high-pressure oil pushes the diaphragm to compress and discharge the gas. 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 structure 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 structure 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 of the diaphragm compressor and a decrease in the gas 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 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 Chinese patent with publication number CN109469603B proposes "a high-pressure diaphragm compressor, its oil replenishment system and oil replenishment method", which realizes the oil replenishment pressure control of the diaphragm compressor suction stroke or exhaust stroke by adding a relief valve passage between the oil replenishment plunger pump and the oil replenishment check valve, 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 pumps will affect the suction volume, resulting in insufficient single-turn suction volume. How to reasonably set the plunger pump stroke volume, that is, the control of 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, since the actual leakage of the diaphragm compressor plunger pump is difficult to measure accurately, the plunger pump stroke volume selection in the previous design stage often adopts the 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 the diaphragm compressor hydraulic oil and the generation of bubbles in the cylinder occur throughout the process, and the traditional single plunger pump structure cannot achieve full-process adaptation of the diaphragm compressor cavity oil pressure and leakage characteristics of oil replenishment. Summary of the invention

[0005] The purpose of the present invention is to address the problems in the above-mentioned prior art and to 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 oil replenishment of the plunger pump 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 entire diaphragm compressor.

[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, comprising a plurality of plunger pumps, wherein the plurality of plunger pumps are driven by a plunger-driven eccentric wheel, and the plurality of plunger pumps replenish oil to a diaphragm head structure of the diaphragm compressor through respective oil replenishment passages in phases under the driving, and the diaphragm head structure overflows excess hydraulic oil to the outside through an oil 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 to the outside through a 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.

[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 phase.

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

[0010]

[0011] In the formula, 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 eccentricity 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] In the formula, 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 this time, the membrane head structure performs the air suction process. During the 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 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] In the formula, is the crank angle corresponding to different cylinder pressure moments of the diaphragm head structure within one cycle; The pressure in the cylinder of the diaphragm head structure during the intake phase is equal to the defined relative pressure p relative The crank angle at The pressure in the cylinder of the diaphragm head structure during the exhaust phase is equal to the defined relative pressure p relative The crank angle at

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

[0022] p relative = x 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 It meets the following expression:

[0032]

[0033] In the formula, 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] In the second aspect, a design method for a full-process oil replenishment system of 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 area of ​​multiple plunger pumps is 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 diaphragm 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 leakage amounts of multiple plunger pumps corresponding to different oil replenishment phase regions, 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, a suitable 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, and 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] Through multiple plunger pumps driven by a plunger and an eccentric wheel, the oil pressure in the diaphragm compressor cavity is adapted during the entire process of air intake, compression and exhaust of the diaphragm compressor's diaphragm head structure, and the diaphragm compressor is replenished during the entire operation process. By reasonably dividing different pressure intervals or oil replenishment intervals, multiple plunger pumps can be replenished in time and in sections. By reasonably arranging the plunger pump cavity volume, the matching accuracy of the oil injection amount and the leakage amount is higher, and accurate full-process oil replenishment operations adapted to different pressure intervals in the diaphragm compressor cavity are 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 realize the full-process oil replenishment of the diaphragm compressor without oil replenishment time gaps within one cycle. The present invention uses multiple plunger pumps to replenish oil in the oil chamber of the diaphragm compressor in different pressure ranges, working stages, and time periods, overcoming 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, so that the amount of oil replenishment can 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, and achieve 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, optimize the performance of the plunger pump, and improve the overall reliability of the diaphragm compressor. In the actual diaphragm compressor debugging process, 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 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.

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

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

[0044] Figure 3 A schematic diagram of the oil circuit structure of the gap leakage between the cylinder liner and the piston according to an embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of the oil pressure change in the cylinder of the diaphragm compressor according to an embodiment of the present invention;

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

[0047] Figure 6 It is a schematic diagram of the whole process oil replenishment system of the diaphragm compressor with a three-plunger pump structure with a phase angle of 120° 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 attached 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 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.

[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. When driven, 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 to the outside 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 out 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.

[0052] Example 1

[0053] like Figure 1 As shown, the full-process oil replenishment system of the diaphragm compressor of the embodiment of the present invention includes: a first plunger pump 11, a second plunger pump 12, a plunger driving 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 both sides of the plunger-driven eccentric wheel 2, and replenish oil to the diaphragm head structure 3 through the first oil replenishment oil circuit L11 and the second oil replenishment oil circuit L12 in phases. The diaphragm head structure 3 overflows excess hydraulic oil through the overflow oil circuit L2. The piston assembly 4 drives the hydraulic oil in the cylinder of the diaphragm head structure 3 to move and increase pressure. The hydraulic oil in the cylinder of the diaphragm head structure 3 leaks out through the gap leakage oil circuit L3 between the diaphragm head structure 3 and the piston assembly 4. In this way, the dynamic balance process 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 - plunger displacement of the first plunger pump 11, in m; r - radius of the plunger driving eccentric wheel 2, in m; θ - rotation angle of the plunger driving eccentric wheel 2, in rad; a - eccentricity of the plunger pump driving eccentric wheel 2, in m; v zs - The speed of the plunger of the first plunger pump 11, in m·s -1 .

[0058] like Figure 2 As shown, the oil replenishment 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 T, 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 at t 1 The speed is the largest at this moment, so the plunger pump plunger has the fastest oil replenishment speed at this time. 2 The same is true for the second piston pump 12. 1 The maximum speed time of the plunger pump plunger from the bottom dead center to the top dead center, in seconds; t 2 It is the maximum speed time of the plunger pump plunger during the movement from the top dead center to the bottom dead center, the unit is s.

[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 sleeve G1 and the piston G2, and its hydraulic oil leakage can be described as:

[0060] m L3 =f(p oil )

[0061] Where: m L3 - Hydraulic oil leakage of gap leakage oil circuit L3, unit: 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, the oil pressure and air pressure in the cavity of the diaphragm compressor diaphragm head structure 3 change synchronously within a cycle T. During the time, the diaphragm compressor diaphragm head structure 3 performs the suction process. During the 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, which is specifically described as:

[0063] p relative = x 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 the 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 a 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 a 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 provided with a pressure in the cylinder of the membrane head structure 3 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°, 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 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 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; - 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 the full process of oil replenishment 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 to be 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 volumes 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 moving double plunger pump is designed during the development of a new single-stage double plunger diaphragm compressor. The specific steps are as follows:

[0076] Step 1: Through the thermal calculation process, the pressure in 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 diaphragm 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 dimensionless pressure curve of the diaphragm compressor with the crank angle is obtained by AMESim simulation calculation. The dimensionless oil pressure on the ordinate is equal to the relative pressure coefficient X h , the intersection points are A and B, A is taken as the starting point of the oil replenishment of the low-pressure first plunger pump 11, and B is taken as the starting point of the oil replenishment of the high-pressure second plunger pump 12, that is, the first plunger pump 11 is set at a phase angle When the oil is replenished, the second piston pump 12 is set at a phase angle Start refilling oil.

[0078] Step 2: The leakage amount of different replenishment phases is obtained by the aforementioned calculation method of leaked hydraulic oil, and the diameter and stroke size of the plunger pump are designed. In the design, the design strokes 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 based on this.

[0079] Step 3: According to the structure of the first plunger pump 11 and the structure of the second plunger pump 12, select the appropriate ball bearing 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.

[0080] The method for oil replenishment of a single-stage diaphragm compressor with dual plunger pumps throughout the entire process described in this embodiment can achieve low-pressure oil replenishment and high-pressure oil replenishment in separate phases. The high-pressure oil replenishment, i.e., the phase zone where the second plunger pump 12 is located during the oil replenishment phase, is located at a high compression and exhaust pressure, with a large amount of leakage at the piston, and a large pressure variation range, and bubbles are easily generated in the oil chamber. Therefore, the second plunger pump 12 is suitable for a larger volume chamber, and the low-pressure oil replenishment, i.e., the phase zone where the first plunger pump 11 is located during the oil replenishment phase, is located at a low suction and compression pressure, with a small amount of leakage at the piston. Oil replenishment by the smaller first plunger pump 11 can avoid the diaphragm compressor from experiencing oil shortage, and reduce the impact of the plunger pump oil replenishment on the suction volume. Thus, this embodiment achieves oil replenishment in separate pressure phases with dual plunger pumps throughout the entire process.

[0081] Example 2

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

[0083] Specifically, Figure 6 As shown, compared with Example 1, the full-process oil replenishment system of the diaphragm compressor described in this embodiment is implemented by setting three plunger pumps installed with 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, and the diaphragm head structure 3 of the diaphragm compressor performs an oil overflow operation through the oil overflow passage L2, and the hydraulic oil in the leakage cavity leaks out through the leakage channel L3 between the piston assembly 4 and the diaphragm head structure 3. Thus, the dynamic balance process of the hydraulic oil quality of the oil replenishment, oil overflow and oil leakage of the hydraulic oil in the cylinder of the diaphragm head structure 3 of the diaphragm compressor is realized.

[0084] Furthermore, compared with Example 1, the three-plunger oil replenishment pump structure of this embodiment can adapt to the pressure changes during the intake, exhaust and compression of the diaphragm compressor to perform leakage replenishment operations more accurately. The matching accuracy of the oil injection amount and the leakage amount can be higher by reasonably arranging the volume of the plunger pump cavity. The design coefficient X in the selection of the pump cavity volume is m It can be smaller, 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; p oil -Hydraulic oil pressure in the cylinder of the diaphragm 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, through the above method, a three-plunger pump with a phase angle of 120° is designed during the development of a new single-stage three-plunger diaphragm compressor. The specific steps are as follows:

[0092] Step 1: The variation of the pressure in the diaphragm compressor cavity with the crank angle is solved through a thermal calculation process. The oil replenishment phase zone 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 boundary point of the oil replenishment phase zone.

[0093] like Figure 7 As shown, we also define p oil is the oil pressure in the cylinder of the diaphragm 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 variation curve of the diaphragm compressor with the crank angle is obtained by AMESim simulation calculation, 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 The crank angle starts to replenish oil, and the second plunger pump 12 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 aforementioned 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. It is solved that the diameter of the first plunger pump 11 is 13mm and the stroke is 8mm, the diameter of the second plunger pump 12 is 13mm and the stroke is 8mm, and the diameter of the third plunger pump 13 is 6.5 and the stroke is 8mm. The plunger pump structure can be designed based on this.

[0095] Step 3: Select appropriate ball bearings to 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 achieve 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, so as to realize the whole process in stages and phase zones. According to the oil replenishment quantity demand in 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. A moderate amount of plunger pump oil replenishment in the low-pressure zone can also avoid 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 realize 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 research and development and design stage of the diaphragm compressor, and optimize the performance of the plunger pump and the overall reliability of the diaphragm compressor.

[0098] 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 full-process oil replenishment system for a diaphragm compressor, characterized in that: The invention comprises a plurality of plunger pumps, which are driven by a plunger-driven eccentric wheel (2). When driven, the plurality of plunger pumps replenish oil to a diaphragm head structure (3) of a diaphragm compressor through respective oil replenishment passages in phases, and the diaphragm head structure (3) overflows excess hydraulic oil to the outside through an oil overflow passage (L2); a piston assembly (4) of the diaphragm compressor drives the hydraulic oil in the cylinder of the diaphragm head structure (3) to move and increase pressure, and the hydraulic oil in the cylinder of the diaphragm head structure (3) leaks to the outside through a gap leakage passage (L3) between the diaphragm head structure (3) and the piston assembly (4); thereby, a dynamic balance of the hydraulic oil quality in the process of replenishing, overflowing and leaking the hydraulic oil in the cylinder of the diaphragm head structure (3) of the diaphragm compressor is achieved.

2. The full-process oil replenishment system for a diaphragm compressor according to claim 1, characterized in that: 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) replenish oil to the diaphragm head structure (3) of the diaphragm compressor through a first oil replenishment oil circuit (L11) and a second oil replenishment oil circuit (L12) in phases.

3. The whole process oil replenishment system for diaphragm compressor according to claim 2 is characterized in that: The plunger movement mode of the first plunger pump (11) conforms to the following expression: In the formula, x zs is the plunger displacement of the first plunger pump (11); r is the radius of the plunger-driven eccentric wheel (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).

4. The full-process oil replenishment system for a diaphragm compressor according to claim 3 is 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) meets the following expression: m L3 =f(p oil ) In the formula, 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).

5. The full-process oil replenishment system for a diaphragm compressor according to claim 4, characterized in that: The oil pressure and air pressure in the cylinder of the diaphragm head structure (3) of the diaphragm compressor change synchronously within a period T. During this time, the membrane head structure (3) performs an air suction process. During the time, the membrane head structure (3) performs the exhaust process.

6. The full-process oil replenishment system for a diaphragm compressor according to claim 5, characterized in that: 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, 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 membrane head structure (3) is set to Calculate using the following formula: In the formula, is the crank angle corresponding to different cylinder pressures of the diaphragm 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 Definition of relative pressure p relative Calculate using the following formula: p relative =x h p oil,max In the formula, χ h is the relative pressure coefficient; p oil,max It is the maximum oil pressure in the cylinder of the diaphragm head structure (3).

7. The full-process oil replenishment system for a diaphragm compressor according to claim 6, characterized in that: The pump chamber volumes of the first plunger pump (11) and the second plunger pump (12) are calculated by the following formula: Where V zs is the pump chamber volume; m is the design coefficient; 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, and then the design parameters of the first plunger pump (11) and the second plunger pump (12) are determined.

8. The diaphragm compressor full-process oil replenishment system according to claim 1, characterized in that: The plunger pump is composed of a first plunger pump (11), a second plunger pump (12) and a third plunger pump (13). The installation phase angle between the first plunger pump (11), the second plunger pump (12) and the third plunger pump (13) is 120°. 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.

9. The diaphragm compressor full-process oil replenishment system according to claim 8, 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 It meets the following expression: In the formula, p zs is the hydraulic oil pressure of the plunger pump; p oil is the hydraulic oil pressure in the cylinder of the diaphragm head structure (3).

10. A design method for a full-process oil replenishment system for a diaphragm compressor, 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 area of ​​multiple plunger pumps is obtained; Define p oil is the oil pressure in the cylinder of the diaphragm head structure (3), and the dimensionless oil pressure is Here, the maximum oil pressure p in the cylinder of the diaphragm head structure (3) is taken as 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 leakage amounts of multiple plunger pumps corresponding to different oil replenishment phase regions, 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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