Bidirectional plunger pump and control method

Abstract

The invention provides a bidirectional plunger pump and a control method, and belongs to the technical field of booster pumps, the bidirectional plunger pump comprises at least one plunger pump unit, and each plunger pump unit comprises a cylinder body, a plunger and a transmission device used for driving the plunger to move; the plunger comprises a plunger head, a plunger body and a connector; the cylinder body comprises a first compression cavity matched with the plunger head in size and a second compression cavity matched with the plunger body in size. According to the bidirectional plunger pump and the control method, the plunger acts bidirectionally, and compared with a conventional booster pump, the pump speed can be reduced under the condition of the same output pressure and flow, so that the service life of the plunger pump is prolonged; in addition, the plunger pump can 100% utilize the water pressure of the incoming water, the plunger is driven to be pressurized on the basis of the water pressure of the incoming water to reach the target water pressure, and therefore the energy-saving effect is achieved. According to the control method, the target conveying capacity can be preset, and efficiency maximization is achieved by adjusting the working parameters of the frequency converter on the basis that the target conveying capacity can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic pumps, and more specifically relates to a double-acting plunger pump and a control method thereof. Background Art

[0002] A plunger pump is a pump that delivers liquids by reciprocating the plunger in the cylinder. It is usually used in high pressure, high viscosity or situations where precise flow control is required. Plunger pumps have the characteristics of large delivery flow, high pressure, good stability and high precision. They are widely used in engineering machinery, metallurgy, petrochemical industry, shipbuilding, agricultural machinery and other fields.

[0003] A booster pump is a pump used to increase fluid pressure, also known as a booster or booster pump station. A booster pump mechanically transfers fluid from a high-pressure area to a higher-pressure area, thereby increasing the pressure of the fluid. Traditional booster pumps can only work in one direction, and the incoming water pressure is lost, resulting in a waste of resources. Summary of the invention

[0004] Based on this, an object of the present invention is to provide a double-acting plunger pump for increasing liquid pressure, the double-acting plunger pump comprising at least one plunger pump unit, the plunger pump unit comprising a cylinder, a plunger, and a transmission device for driving the plunger to move; the plunger comprises a plunger head, a plunger body, and a connector; the cylinder comprises a first compression chamber matching the size of the plunger head, and a second compression chamber matching the size of the plunger body; the first compression chamber is provided with a first input port and a first output port, the second compression chamber is provided with a second input port and a second output port, and the first input port, the first output port, the second input port, and the second output port are respectively provided with a one-way valve; the connector passes through the end of the cylinder and is connected to the transmission device; The transmission device can drive the plunger to reciprocate. When the plunger moves in the first direction, the plunger head moves in the first compression chamber to generate negative pressure, and the liquid input into the cylinder body flows into the first compression chamber from the first input port, and the energy of the incoming water is used to do work; the plunger body moves in the second compression chamber to generate positive pressure, and the liquid in the second compression chamber flows out of the cylinder body from the second output port; When the plunger moves in the second direction, the plunger head moves in the first compression chamber to generate positive pressure, and the liquid in the first compression chamber flows out of the cylinder body from the first output port; the plunger body moves in the second compression chamber to generate negative pressure, and the liquid input into the cylinder body flows into the second compression chamber from the second input port, and work is performed using the energy of the incoming water.

[0005] Preferably, the plunger surface areas on the plunger head and the plunger body for pushing the liquid to flow under pressure are equal.

[0006] Preferably, the inner wall of the cylinder body in contact with the plunger head is provided with a first sealing component, the inner wall of the cylinder body in contact with the plunger body is provided with a second sealing component, and the inner wall of the cylinder body in contact with the connecting head is provided with a third sealing component; The first sealing assembly, the second sealing assembly and the third sealing assembly are used to prevent the liquid inside the cylinder from leaking.

[0007] Preferably, the first sealing assembly and / or the second sealing assembly and / or the third sealing assembly comprises a sealing ring groove arranged on the inner wall of the cylinder body and a Y-shaped sealing ring arranged in the sealing ring groove, and the Y-shaped sealing ring has a wear compensation function.

[0008] Preferably, the cylinder body further comprises a first lubricating cavity having a size matching that of the plunger body; a first lubricating oil tank is arranged outside the cylinder body, and a first lubricating channel is arranged between the first lubricating oil tank and the inside of the cylinder body, and the first lubricating channel is used to transport lubricating oil to the first lubricating cavity; When the plunger moves in the first direction, the plunger body moves in the first lubrication cavity to generate negative pressure, and the lubricating oil in the first lubricating oil tank flows into the first lubricating cavity through the first lubricating channel; when the plunger moves in the second direction, the plunger body moves in the first lubricating cavity to generate positive pressure, and the lubricating oil in the first lubricating cavity flows into the first lubricating oil tank through the first lubricating channel; The lubricating oil in the first lubricating cavity can adhere to the outer surface of the plunger head, the outer surface of the plunger body and the inner surface of the cylinder body; when the plunger moves back and forth, the lubricating oil can delay the wear of the first sealing component and the second sealing component to extend the service life of the first sealing component and the second sealing component.

[0009] Preferably, the contact portion between the cylinder body and the connecting head further comprises an annular extension portion, and the connecting head passes through the extension portion; a third sealing groove is provided on the inner wall of the extension portion, and the third sealing assembly is provided in the third sealing groove; A second lubrication cavity is provided in the radial direction inside the extension portion, and the second lubrication cavity is connected to the third sealing groove; the second lubrication cavity can be filled with lubricating oil, and the lubricating oil in the second lubrication cavity can delay the wear of the third sealing assembly to extend the life of the third sealing assembly.

[0010] Preferably, the plunger surface has a PEEK self-lubricating material layer.

[0011] Preferably, the double-acting plunger pump includes a plurality of plunger pump units; the transmission device includes a crankshaft and a connecting rod connecting the crankshaft and the plunger; the number of connecting rods is consistent with the number of plunger pump units, and the plurality of connecting rods are respectively connected to the connecting heads of the plurality of plunger pump units, and the angles of the plurality of connecting rods are evenly distributed in the circumferential direction of the crankshaft.

[0012] Preferably, the double-acting plunger pump includes three plunger pump units; the transmission device includes three connecting rods, one end of the three connecting rods is respectively connected to the crankshaft, and the other end is connected to the connecting heads respectively connected to the three plunger pump units; the angles of the three connecting rods are evenly distributed in the circumferential direction of the crankshaft.

[0013] Preferably, the cylinder bodies of the three plunger pump units form a cylinder body assembly, and the cylinder body assembly is provided with a total input channel and a total output channel; the total input channel is connected to the first input port and the second input port of the three plunger pump units; the total output channel is connected to the first output port and the second output port of the three plunger pump units.

[0014] Preferably, the double-acting piston pump also includes an input pressure sensor connected to the total input channel, an output pressure sensor connected to the total output channel, a flow sensor connected to the total input channel or the total output channel, a motor for driving the crankshaft to rotate, a frequency converter and a controller for controlling the motor; the controller is connected to the input pressure sensor, the flow sensor, the output pressure sensor and the frequency converter, and the controller is used to obtain signals from the input pressure sensor, the flow sensor and the output pressure sensor and to adjust the working parameters of the frequency converter.

[0015] The present invention also provides a control method for a double-acting plunger pump, comprising: Obtain the target delivery capacity, which refers to the total volume of liquid delivered by the double-acting plunger pump during the working hours; Calculate the target output flow rate based on the target delivery capacity. The target output flow rate refers to the output liquid flow rate that the double-acting plunger pump needs to achieve; Obtain the inlet pressure of the total input channel of the double-acting plunger pump, the outlet pressure of the total output channel of the double-acting plunger pump, and the actual output flow of the double-acting plunger pump; Adjust the inverter operating parameters according to the target output flow, actual output flow, inlet pressure and outlet pressure.

[0016] Beneficial effects: According to an embodiment of the present invention, a bidirectional piston pump and a control method are provided, wherein the piston performs bidirectional work, and compared with a conventional booster pump, the pump speed can be reduced under the same output pressure and flow rate conditions to extend the life of the piston pump; in addition, the piston pump can 100% utilize the incoming water pressure to drive the piston to boost the pressure on the basis of the incoming water pressure to reach the target water pressure, thus also having an energy-saving effect. The control method can preset the target delivery capacity, and adjust the inverter working parameters on the basis of being able to achieve the target delivery capacity to achieve maximum efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present disclosure includes drawings, which should be considered to be included in and constitute a part of the specification, and together with the specification, illustrate various exemplary embodiments, features and aspects of the present disclosure, and are used to explain the principles of the present disclosure. The present invention will be more fully understood through the following detailed description in conjunction with the drawings. Among them: Figure 1 is a schematic diagram of a use state of a double-acting plunger pump according to an embodiment of the present invention; Figure 2 is a top view of a double-acting plunger pump according to an embodiment of the present invention; Figure 3 yes Figure 2 Sectional view of AA in the middle; Figure 4 yes Figure 3 A partial enlarged view of point D in the middle; Figure 5 yes Figure 3 A partial enlarged view of point E in the middle; Figure 6 yes Figure 3 A partial enlarged view of point F in the middle; Figure 7 yes Figure 2 Cross-sectional view of the middle BB; Figure 8 yes Figure 2 Cross-sectional view of CC; Fig. 9 is a schematic diagram of the internal structure of a plunger pump unit according to an embodiment of the present invention; Fig.10 yes Fig. 9 A partial enlarged view of the G in the middle; Fig.11 yes Fig. 9 A partial enlarged view of the H in the middle; Fig.12 is a schematic diagram of the internal structure of a first input port, a second input port, a total input channel, and a total output channel according to an embodiment of the present invention; Fig.13 is a schematic diagram of the internal structure of a first lubrication channel and a first lubrication cavity according to an embodiment of the present invention; Fig.14 is a schematic diagram of the internal structure of the second input port and the second output port according to an embodiment of the present invention; Fig.15 is a schematic structural diagram of an extension portion according to an embodiment of the present invention; Among them: cylinder body 10, plunger head 11, plunger body 12, connector 13, first compression chamber 14, second compression chamber 15, first input port 16, first output port 17, second input port 18, second output port 19, first step 21, first lubrication chamber 22, annular channel 23, elastic member 24, ball 25, second lubrication chamber 26, first sealing assembly 31, second sealing assembly 32, third sealing assembly 33, first lubrication oil tank 34, crankshaft 35, connecting rod 36, cylinder assembly 40, total input channel 41, total output channel 42, plug body 43, first lubrication hole 44, stud pipe 45, input collecting channel 46, output collecting channel 47, flow sensor 52, sealing ring 55, driver 61, reducer 62, extension part 63, second lubrication oil tank 64, third sealing groove 65, radial lubrication channel 661, axial lubrication channel 662, positioning ring 67. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described in detail below through embodiments and in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.

[0019] A plunger pump is a pump that transports liquids by reciprocating a plunger in a cylinder 10, and is usually used in situations where high pressure, high viscosity, or where precise flow control is required. Plunger pumps have the characteristics of large delivery flow, high pressure, good stability, and high precision, and are widely used in engineering machinery, metallurgy, petrochemicals, ships, agricultural machinery, and other fields. A booster pump is a pump used to increase fluid pressure, also known as a booster or booster pump station. A booster pump transports fluid from a low-pressure area to a high-pressure area through mechanical action, thereby increasing the pressure of the fluid. Traditional booster pumps can only work in one direction, and the incoming water pressure is lost, resulting in a waste of resources.

[0020] In order to solve the above problems, the purpose of the present invention is to provide a double-acting plunger pump for increasing liquid pressure, the double-acting plunger pump includes at least one plunger pump unit, the plunger pump unit includes a cylinder 10, a plunger, and a transmission device for driving the plunger to move; the plunger includes a plunger head 11, a plunger body 12, and a connector 13; the cylinder 10 includes a first compression chamber 14 matching the size of the plunger head 11, and a second compression chamber 15 matching the size of the plunger body 12; the first compression chamber 14 is provided with a first input port 16 and a first output port 17, the second compression chamber 15 is provided with a second input port 18 and a second output port 19, and the first input port 16, the first output port 17, the second input port 18, and the second output port 19 are respectively provided with a one-way valve; the connector 13 passes through the end of the cylinder 10 and is connected to the transmission device; The transmission device can drive the plunger to reciprocate. When the plunger moves in the first direction, the plunger head 11 moves in the first compression chamber 14 to generate negative pressure, and the liquid input into the cylinder body 10 flows into the first compression chamber 14 from the first input port 16, and at the same time, work is performed by using the energy of the incoming water; the plunger body 12 moves in the second compression chamber 15 to generate positive pressure, and the liquid in the second compression chamber 15 flows out of the cylinder body 10 from the second output port 19; When the plunger moves in the second direction, the plunger head 11 moves in the first compression chamber 14 to generate positive pressure, and the liquid in the first compression chamber 14 flows out of the cylinder body 10 from the first output port 17; the plunger body 12 moves in the second compression chamber 15 to generate negative pressure, and the liquid input into the cylinder body 10 flows into the second compression chamber 15 from the second input port 18, and at the same time, work is done by using the energy of the incoming water.

[0021] In this embodiment, Figure 3 , Fig. 9 As shown, there is a space inside the cylinder body 10 for the plunger to move, and the plunger includes three parts, namely, a plunger head 11, a plunger body 12, and a connector 13, which are arranged in sequence. The plunger head 11, the plunger body 12, and the connector 13 are a whole. The plunger head 11 and the plunger body 12 are kept inside the cylinder body 10, and the connector 13 extends through one end of the cylinder body 10 to the outside of the cylinder body 10. The connector 13 is connected to a transmission device outside the cylinder body 10. The transmission device can be a crankshaft 35, a transmission shaft, etc. The transmission device can be connected to a driver 61 to realize external force driving the plunger to move. The driver 61 can be a motor that drives the crankshaft 35 to rotate.

[0022] In some embodiments, a reducer 62 is further provided between the driver 61 and the crankshaft 35 , and the reducer is used to increase the torque.

[0023] In some embodiments, the diameter of the plunger head 11 is smaller than the diameter of the plunger body 12, and the diameter of the connector 13 is smaller than the diameter of the plunger body 12. A first step 21 is provided inside the cylinder body 10, and the first step 21 divides the space inside the cylinder body 10 into a large diameter area and a small diameter area. The outer diameter of the plunger head 11 matches the inner diameter of the small diameter area, and the plunger head 11 moves in the small diameter area; the outer diameter of the plunger body 12 matches the inner diameter of the large diameter area, and the plunger body 12 moves in the large diameter area.

[0024] The plunger body 12 divides the large diameter area into two cavities. The cavity near the small diameter area is the first lubrication cavity 22, and the area near the connector 13 is the second compression cavity 15. The area at the end of the plunger head 11 is the first compression cavity 14. The first compression cavity 14 is provided with a first input port 16 and a first output port 17, and the second compression cavity 15 is provided with a second input port 18 and a second output port 19. One end of the first input port 16 and the first output port 17 are connected to the interior of the first compression cavity 14, and the other end of the first input port 16 and the first output port 17 are connected to the outside of the first compression cavity 14. One end of the second input port 18 and the second output port 19 are connected to the interior of the second compression cavity 15, and the other end of the second input port 18 and the second output port 19 are connected to the outside of the second compression cavity 15.

[0025] In some embodiments, the first input port 16 and the second input port 18 are connected to the channel for inputting the liquid of the plunger pump, and the first output port 17 and the second output port 19 are connected to the channel for outputting the liquid of the plunger pump. Specifically, the liquid input to the plunger pump is connected to the first input port 16 and the second input port 18 through a three-way connector, and the liquid output from the plunger pump is also connected to the first output port 17 and the second output port 19 through a three-way connector.

[0026] In some embodiments, one-way valves are respectively provided on the first input port 16, the first output port 17, the second input port 18, and the second output port 19. The one-way valve of the first input port 16 is configured to be able to input liquid only into the first compression chamber 14; the one-way valve of the first output port 17 is configured to be able to output liquid only from the first compression chamber 14. The one-way valve of the second input port 18 is configured to be able to input liquid only into the second compression chamber 15; the one-way valve of the second output port 19 is configured to be able to output liquid only from the second compression chamber 15.

[0027] One-way valve Figure 4 , Figure 5 As shown, the one-way valve includes an annular channel 23, a ball 25 that can fit on the inclined surface, and an elastic member 24 that pushes the ball 25 to fit on the inclined surface. The annular channel 23 of some one-way valves has an inclined surface, and the inclined surface of other one-way valves is set on the cylinder body 10, and the end with a larger inclined surface opening faces the direction of one-way flow of liquid. When the liquid pressure at the end with a smaller inclined surface opening is greater than the liquid pressure at the end with a larger inclined surface opening, the liquid pressure at the end with a smaller inclined surface opening can push the ball 25 to move away from the ball 25, and the channel in the center of the annular channel 23 is opened, and the liquid on the side with a larger liquid pressure can flow in the direction of the side with a smaller liquid pressure. When the liquid pressure at the end with a smaller inclined surface opening is less than the liquid pressure at the end with a larger inclined surface opening, the liquid pressure at the end with a larger inclined surface opening pushes the ball 25 to fit closely with the inclined surface to prevent the flow of liquid.

[0028] When the liquid pressure inside the first compression chamber 14 is lower than the liquid pressure outside the first input port 16, the liquid outside the first input port 16 can flow into the first compression chamber 14 through the first input port 16; when the liquid pressure inside the first compression chamber 14 is higher than the liquid pressure outside the first output port 17, the liquid in the first compression chamber 14 can flow out through the first output port 17.

[0029] Similarly, when the liquid pressure inside the second compression chamber 15 is lower than the liquid pressure outside the second input port 18, the liquid outside the second input port 18 can flow into the second compression chamber 15 through the second input port 18; and when the liquid pressure inside the second compression chamber 15 is higher than the liquid pressure outside the second output port 19, the liquid in the second compression chamber 15 can flow out through the second output port 19.

[0030] The transmission device drives the plunger to reciprocate. When the plunger moves in the first direction, the first movement direction refers to the plunger moving away from the cylinder body 10. The internal volume of the first compression chamber 14 increases and the pressure decreases. The plunger head 11 moves in the first compression chamber 14 to generate negative pressure, and the liquid input into the cylinder body 10 flows into the first compression chamber 14 from the first input port 16. The internal volume of the second compression chamber 15 decreases and the pressure increases. The plunger body 12 moves in the second compression chamber 15 to generate positive pressure, and the liquid in the second compression chamber 15 flows out of the cylinder body 10 from the second output port 19.

[0031] On the contrary, when the plunger moves in the second direction, the second movement direction refers to the direction in which the plunger moves toward the cylinder body 10, the internal volume of the first compression chamber 14 is small, the pressure increases, the plunger head 11 moves in the first compression chamber 14 to generate positive pressure, and the liquid in the first compression chamber 14 flows out of the cylinder body 10 from the first output port 17. The internal volume of the second compression chamber 15 increases and the pressure decreases, the plunger body 12 moves in the second compression chamber 15 to generate negative pressure, and the liquid input into the cylinder body 10 flows into the second compression chamber 15 from the second input port 18.

[0032] The reciprocating movement of the plunger performs work in both directions and completes two outward output processes. At the same time, the incoming water pressure can also perform work on driving the plunger to move. In some embodiments, for example, if the incoming water pressure is 20 MPa and a pressure increase of 5 MPa is required, the driver 61 only needs to push the plunger to move to generate a pressure of 5 MPa to increase the pressure of the output water to 25 MPa.

[0033] For a traditional booster pump with a compensating tube (taking plunger diameter: large plunger Φ36mm, small plunger Φ24mm as an example): Assuming the incoming water pressure is 20 MPa, the equipment needs to boost the pressure by 5 MPa, and the final output pressure is 25 MPa.

[0034] S1 piston area: S1=1.8*1.8*3.14=10.1736cm 2 S2 piston area: S2 = 1.8 * 1.8 * 3.14 – 1.2 * 1.2 * 3.14 = 5.652 cm 2 The thrust required to output 25 MPa is: F=25*10.1736*10=2543.4kg S2 auxiliary compensation thrust: Fcompensation = 20*5.652*10 = 1130.4kg The plunger needs to do work thrust: F plunger = FF complement = 2543.4-1130.4 = 1413kg The S1 piston is the piston at one end that contacts the incoming water and the outgoing water, and the S2 piston is the piston connected to one end of the driver 61 .

[0035] For the plunger pump unit of this embodiment: The area of ​​S1 is equal to S2, S1=S2=1.8*1.8*3.14=10.1736cm 2 The thrust required to output 25 MPa is: F=25*10.1736*10=2543.4kg S2 auxiliary compensation thrust: Fcompensation = 20*10.1736*10 = 2034.72kg The plunger needs to do work thrust: F plunger = FF complement = 2543.4-2034.72 = 508.68kg Among them, S1 is the plunger surface area of ​​the plunger head 11 used to promote the flow of liquid, and S2 is the plunger surface area of ​​the plunger body 12 used to promote the flow of liquid. Although the diameter of the plunger body 12 is larger than the diameter of the plunger head 11, the plunger surface area of ​​the plunger body 12 that actually promotes the flow of liquid is the diameter of the plunger body 12 minus the diameter of the connector 13. In some embodiments, the diameter of the connector 13 is equal to the diameter of the plunger head 11. The plunger surface areas on the plunger head 11 and the plunger body 12 used to promote the flow of liquid under pressure are equal.

[0036] Therefore, the incoming water pressure of this embodiment can fully participate in the compensation of the boost pressure.

[0037] In terms of energy consumption: with a daily water injection of 50 cubic meters, the traditional booster pump wastes 22 cubic meters of 20 MPa high-pressure water.

[0038] Hydraulic pump power (KW) = head (m) × flow (m3 / s) × fluid density (water 1000kg / m3) ÷ 102 (power conversion coefficient) ÷ pump efficiency (about 69%) W=2000*(15.28L / min / 60)*1000 / (102*0.69)= 7.2369KW Daily power consumption: 7.2369KW ╳ 24h=173.69 Kw.h For high-pressure water booster pumps, this design fully utilizes the water energy and compensates 100% of the water pressure, which is highly efficient and energy-saving.

[0039] The plunger reciprocates in both directions to perform work. Under the condition of the same displacement and the same area of ​​the plunger, the pump speed is reduced by half and the service life is extended by more than 2 times.

[0040] Further, the inner wall of the cylinder body 10 in contact with the plunger head 11 is provided with a first sealing component 31, the inner wall of the cylinder body 10 in contact with the plunger body 12 is provided with a second sealing component 32, and the inner wall of the cylinder body 10 in contact with the connector 13 is provided with a third sealing component 33; The first sealing assembly 31 , the second sealing assembly 32 , and the third sealing assembly 33 are used to prevent the liquid inside the cylinder body 10 from leaking.

[0041] In this embodiment, Figure 3 , Figure 5 , Figure 6 , Fig. 9 , Fig.10 , Fig.14 As shown, the first sealing component 31, the second sealing component 32, and the third sealing component 33 are sealing rings 55, the inner wall of the small diameter area of ​​the cylinder body 10 is provided with a first sealing groove, the first sealing component 31 is sleeved on the outer surface of the plunger head 11, and the first sealing component 31 is in the first sealing groove. The first sealing component 31 is used to seal the gap between the plunger head 11 and the inner wall of the small diameter area of ​​the cylinder body 10 to prevent the liquid in the first compression chamber 14 from leaking.

[0042] The second sealing assembly 32 is sleeved on the outer surface of the plunger body 12, and a second sealing groove is provided on the inner wall of the large diameter area of ​​the cylinder body 10, and the second sealing assembly 32 is in the second sealing groove. The third sealing assembly 33 is sleeved on the outer surface of the connector 13, and a third sealing groove 65 is provided on the through-portion of the connector 13 passing through the cylinder body 10, and the third sealing assembly 33 is in the third sealing groove 65. The second sealing assembly 32 and the third sealing assembly 33 are used to seal the gap between the plunger body 12 and the large diameter area of ​​the cylinder body 10 and the gap between the connector 13 and the through-portion of the cylinder body 10, so as to prevent the liquid in the second compression chamber 15 from leaking.

[0043] Furthermore, the first sealing assembly 31 and / or the second sealing assembly 32 and / or the third sealing assembly 33 include a sealing ring groove provided on the inner wall of the cylinder body 10 and a Y-shaped sealing ring 55 provided in the sealing ring groove, and the Y-shaped sealing ring 55 has a wear compensation function.

[0044] In this embodiment, Figure 6 As shown, the Y-shaped sealing ring 55 is a sealing ring 55 of a special shape, and its cross section is Y-shaped. The Y-shaped sealing ring 55 is usually used for dynamic sealing or high-pressure sealing applications, and has good sealing performance and wear resistance. The Y-shaped sealing ring 55 is usually made of rubber, silicone, fluororubber and other materials, and has good elasticity and corrosion resistance. The direction of the Y-shaped opening is toward the direction of high pressure, and the high-pressure liquid can push the Y-shaped opening to open, so that the Y-shaped sealing ring 55 maintains fit with the cylinder body 10 and the plunger. The Y-shaped sealing ring 55 has a wear compensation function. After the Y-shaped sealing ring 55 is worn, the high pressure pressure tends to open the Y-shaped opening at a larger angle to maintain fit with the cylinder body 10 and the plunger.

[0045] Furthermore, the cylinder body 10 further includes a first lubricating cavity 22 having a size matching that of the plunger body 12; a first lubricating oil tank 34 is disposed outside the cylinder body 10, and a first lubricating channel is disposed between the first lubricating oil tank 34 and the inside of the cylinder body 10, and the first lubricating channel is used to transport lubricating oil to the first lubricating cavity 22; When the plunger moves in the first direction, the plunger body 12 moves in the first lubricating cavity 22 to generate negative pressure, and the lubricating oil in the first lubricating oil tank 34 flows into the first lubricating cavity 22 through the first lubricating passage; when the plunger moves in the second direction, the plunger body 12 moves in the first lubricating cavity 22 to generate positive pressure, and the lubricating oil in the first lubricating cavity 22 flows into the first lubricating oil tank 34 through the first lubricating passage; The lubricating oil in the first lubrication cavity 22 can adhere to the outer surface of the plunger head 11, the outer surface of the plunger body 12 and the inner surface of the cylinder body 10; when the plunger moves back and forth, the lubricating oil can delay the wear of the first sealing assembly 31 and the second sealing assembly 32 to extend the life of the first sealing assembly 31 and the second sealing assembly 32.

[0046] In this embodiment, Figure 3 , Figure 7 , Fig. 9As shown, the plunger body 12 divides the large diameter area into two cavities, and the cavity close to the small diameter area is the first lubricating cavity 22. The first lubricating channel can be a round hole drilled on the cylinder body 10, connecting the first lubricating cavity 22 and the first lubricating oil tank 34. The first lubricating oil tank 34 can be a closed space. When the plunger moves in the first direction, the volume of the first lubricating cavity 22 increases and the pressure decreases. The lubricating oil flows from the first lubricating oil tank 34 to the inside of the first lubricating cavity 22. At the same time, the lubricating oil adheres to the outer surface of the plunger head 11 and the surface of the first lubricating cavity 22, and the pressure in the first lubricating oil tank 34 decreases. When the plunger moves in the second direction, the volume of the first lubricating cavity 22 decreases and the pressure increases. The lubricating oil in the first lubricating cavity 22 flows into the first lubricating oil tank 34, and the lubricating oil on the outer surface of the plunger head 11 and the surface of the first lubricating cavity 22 adheres to the first compression cavity 14 and the second compression cavity 15 as well as the surface of the plunger body 12. Therefore, when the plunger reciprocates, the lubricating oil can delay the wear of the first sealing assembly 31 and the second sealing assembly 32 to extend the service life of the first sealing assembly 31 and the second sealing assembly 32 .

[0047] In some embodiments, two first sealing assemblies 31 are sleeved on the plunger head 11, and two second sealing assemblies 32 are sleeved on the plunger body 12. The multiple first sealing assemblies 31 and multiple second sealing assemblies 32 on the plunger are distributed along the axial direction of the plunger. Correspondingly, the small diameter area of ​​the cylinder body 10 is provided with two first sealing grooves along the axial direction, and the large diameter area of ​​the cylinder body 10 is provided with two second sealing grooves along the axial direction. The multiple first sealing assemblies 31 and multiple second sealing assemblies 32 can increase the sealing performance and prevent the liquid in the cylinder body 10 from leaking.

[0048] Furthermore, the contact portion between the cylinder body 10 and the connector 13 further includes an annular extension portion 63, through which the connector 13 passes; a third sealing groove 65 is provided on the inner wall of the extension portion 63, and the third sealing assembly 33 is provided in the third sealing groove 65; A second lubrication cavity 26 is provided in the radial direction inside the extension portion 63 , and the second lubrication cavity 26 is connected to the third sealing groove 65 ; the second lubrication cavity 26 can be filled with lubricating oil, and the lubricating oil in the second lubrication cavity 26 can delay the wear of the third sealing assembly 33 to extend the life of the third sealing assembly 33 .

[0049] In this embodiment, Figure 3 , Figure 4 , Figure 5 , Fig. 9 , Fig.10 , Fig.11 As shown, the extension portion 63 is annular. To facilitate replacement of the third sealing assembly 33 , the extension portion 63 is detachably mounted to the through-portion of the connecting head 13 passing through the cylinder body 10 by means of bolts or other fasteners.

[0050] A third sealing groove 65 is provided on the inner wall of the extension portion 63, and the third sealing groove 65 is provided in the circumferential direction. The second lubricating cavity 26 is provided in the radial direction of the extension portion 63. In order to facilitate the processing of the second lubricating oil cavity, the second lubricating oil cavity of this embodiment is drilled from the outside of the extension portion 63 to the inside, and the end of the hole outside the extension portion 63 is provided with an internal thread. The internal thread can be screwed into a matching plug body 43 with an external thread. A sealing ring 55 is provided on the plug body 43. When filling the second lubricating oil cavity with lubricating oil, the plug body 43 can be taken out and the lubricating oil can be directly filled into the second lubricating oil cavity 26. After the filling is completed, the plug body 43 is replaced.

[0051] In some implementations, a sealing ring 55 is disposed between the extension portion 63 and the main portion of the cylinder body 10 , and the fastener can compress the sealing ring 55 to prevent leakage between the extension portion 63 and the main portion of the cylinder body 10 .

[0052] In some embodiments, Fig.13 As shown, a second lubricating oil tank 64 is also provided outside the extension portion 63 , and the second lubricating oil tank 64 is connected to the second lubricating oil tank 64 . The second lubricating oil tank 64 is used to store a certain amount of lubricating oil, and the lubricating oil in the second lubricating oil tank 64 can flow into the second lubricating oil tank 26 .

[0053] In some embodiments, three third sealing grooves 65 are axially arranged on the inner wall of the extension portion 63, and three third sealing assemblies 33 are sleeved on the connector 13, and the three third sealing assemblies 33 are respectively in the three third sealing grooves 65. When the transmission device is a crankshaft 35 and a crank connecting rod 36, the connector 13 tends to swing inside the extension portion 63, which is more likely to cause wear of the third sealing assembly 33, so the three-layer sealing groove can ensure the sealing performance and prevent leakage.

[0054] In some embodiments, Fig.15 As shown, the second lubrication cavity 26 includes three radial lubrication channels 661 respectively connected to the three third sealing grooves 65, and an axial lubrication channel 662 connecting the three radial lubrication channels 661. At least one radial lubrication channel 661 of the three radial lubrication channels 661 is connected to the second lubrication oil tank 64. In this embodiment, the top end of the radial lubrication channel 661 in the middle position among the three radial lubrication channels 661 is connected to the second lubrication oil tank 64.

[0055] The lubricating oil in the second lubricating oil tank 64 can flow into the three third sealing grooves 65 respectively through the radial lubricating passage 661 and the axial lubricating passage 662 .

[0056] In the specific implementation process, the three radial lubrication channels 661 are holes drilled radially along the extension portion 63. The positions of the three radial lubrication channels 661 correspond to the three third sealing grooves 65. The top of the radial lubrication channel 661 in the middle position is connected to the second lubricating oil tank 64, and plug bodies 43 are set at the top of the radial lubrication channels 661 on both sides to close their ends. The axial lubrication channel 662 connects the three radial lubrication channels 661 to play a diversion role. The axial lubrication channel 662 is a blind hole drilled axially along the extension portion 63, and a plug body 43 is set at its end to play a sealing role.

[0057] In some embodiments, a positioning ring 67 is provided on one side of the extension portion 63 close to the main part of the cylinder body 10. The positioning ring 67 can be inserted into the main part of the cylinder body 10 for connecting the opening of the extension portion. The positioning ring 67 matches the size of the opening and can ensure the coaxiality of the connection with the opening.

[0058] Furthermore, the plunger surface has a PEEK self-lubricating material layer.

[0059] In this embodiment, PEEK is polyetheretherketone, which is a high-performance engineering plastic. PEEK has excellent high temperature resistance, chemical stability, mechanical strength and wear resistance, and is widely used in various fields, including aerospace, automobiles, medical equipment, electronics, chemicals, etc.

[0060] PEEK is an excellent self-lubricating material. The arrangement structure between PEEK molecular chains makes it self-lubricating, which can reduce friction and wear without the need for additional lubricants.

[0061] Furthermore, the bidirectional piston pump includes a plurality of piston pump units; the transmission device includes a crankshaft 35, a connecting rod 36 connecting the crankshaft 35 and the piston; the number of connecting rods 36 is consistent with the number of piston pump units, and the plurality of connecting rods 36 are respectively connected to the connectors 13 of the plurality of piston pump units, and the angles of the plurality of connecting rods 36 are evenly distributed in the circumferential direction of the crankshaft 35. The connecting rod 36 is hinged to the connector 13.

[0062] In this embodiment, the double-acting plunger pump includes a plurality of plunger pump units, and the transmission device simultaneously connects the plurality of plunger pump units. The transmission device may be a crankshaft 35 crank-connecting rod 36 mechanism, and a plurality of crank-connecting rods 36 are arranged on the crankshaft 35. The number of connecting rods 36 is consistent with the number of plunger pump units. The plurality of connecting rods 36 are respectively connected to the connectors 13 of the plurality of plunger pump units, and the angles of the plurality of connecting rods 36 are uniformly distributed in the circumferential direction of the crankshaft 35. Therefore, the plurality of plunger pump units can evenly complete the water inlet and outlet processes, and the outlet water pressure can remain stable with small fluctuations.

[0063] In this embodiment, the double-acting plunger pump includes three plunger pump units; the transmission device includes three connecting rods 36, one end of the three connecting rods 36 is respectively connected to the crankshaft 35, and the other end is connected to the connecting heads 13 respectively connected to the three plunger pump units; the angles of the three connecting rods 36 are evenly distributed in the circumferential direction of the crankshaft 35.

[0064] Furthermore, the cylinder bodies 10 of the three plunger pump units form a cylinder body assembly 40, and the cylinder body assembly 40 is provided with a total input channel 41 and a total output channel 42; the total input channel 41 is connected to the first input port 16 and the second input port 18 of the three plunger pump units; the total output channel 42 is connected to the first output port 17 and the second output port 19 of the three plunger pump units.

[0065] In this embodiment, Figure 1 , Figure 2 As shown, the cylinder assembly 40 is in the shape of a cube, the axis of the plunger is parallel to the length direction of the cylinder assembly 40, the total input channel 41 and the total output channel 42 are arranged along the width direction of the cylinder assembly 40, and the first lubricating oil tank 34 is arranged on the top of the cylinder assembly 40.

[0066] In some embodiments, for the convenience of processing, a hole is drilled in the height direction at the corresponding position of the first compression chamber 14 of the cylinder assembly 40 to penetrate the cylinder assembly 40, and the first output port 17 is above the plunger head 11, and the first input port 16 is below the plunger head 11. Another hole is drilled in the height direction at the corresponding position of the second compression chamber 15 of the cylinder assembly 40 to penetrate the cylinder assembly 40, and the second output port 19 is above the connector 13, and the second input port 18 is below the connector 13. Two plug bodies 43 are respectively arranged at both ends of the hole, and the plug body 43 and the cylinder assembly 40 can be connected by threads. A sealing ring 55 can be arranged at the connection part to close the two ends of the hole, which is the internal channel of the cylinder assembly 40.

[0067] Then drill two holes along the length direction of the cylinder assembly 40, such as Fig.12 As shown, the two holes respectively form an input collecting channel 46 and an output collecting channel 47, the input collecting channel 46 runs through the first input port 16 and the second input port 18, and the output collecting channel 47 runs through the first output port 17 and the second output port 19. Two plug bodies 43 are respectively provided at both ends of the two holes along the length direction of the cylinder assembly 40, the plug body 43 and the cylinder assembly 40 can be connected by threads, and a sealing ring 55 can be provided at the connection part to close the two ends of the hole, which is the internal channel of the cylinder assembly 40.

[0068] Then, two blind holes are drilled along the width direction of the cylinder assembly 40, and the two blind holes respectively penetrate the input manifold channel 46 and the output manifold channel 47 of each plunger pump unit. The main input channel 41 penetrates the input manifold channel 46, and the main output channel 42 penetrates the output manifold channel 47. The main input channel 41 and the main output channel 42 include joints for connecting external pipelines.

[0069] In some embodiments, to facilitate the installation of the one-way valve, Figure 8 , Fig. 9 , Fig.10 , Fig.11 , Fig.14 As shown, for the second input port 18 and the second output port 19: as mentioned above, first drill a hole in the height direction at the corresponding position of the second compression chamber 15 of the cylinder assembly 40, and then drill two holes in the length direction of the cylinder assembly 40 to form an input collecting channel 46 and an output collecting channel 47. Then expand the drilled hole to form a second step on the second output port 19. The elastic member 24 of the one-way valve is a spring, and one end of the spring is placed on the second step. Then, an internal thread is processed at the intersection of the second input port 18 and the input collecting channel 46, and the annular channel 23 is provided with a matching external thread. The ball 25 is installed to contact the spring and then screwed into the annular channel 23 to complete the installation of the one-way valve. Finally, an internal thread is processed at the end of the second input port 18 outside the cylinder assembly 40 and the plug body 43 is installed.

[0070] For the second output port 19, an inclined surface matching the ball 25 is machined at the intersection of the second output port 19 and the second compression chamber 15, and then an internal thread is machined at the intersection of the second output port 19 and the output collecting channel 47. The annular channel 23 is provided with a matching external thread, and then the ball 25 and the elastic member 24 are placed and screwed into the annular channel 23 to complete the installation of the one-way valve. Finally, an internal thread is machined at the end of the second output port 19 outside the cylinder assembly 40 and the plug body 43 is installed. The installation of the first output port 17, the second input port 18 and the corresponding one-way valve is consistent with the above process.

[0071] In some embodiments, a chamfer is provided in the direction of the larger opening of the inclined surface matching the ball 25 , and the chamfer can increase the liquid flow after the ball 25 leaves the inclined surface.

[0072] In some embodiments, the first lubrication channel includes a first lubrication hole 44 on the cylinder assembly 40 and a stud pipe 45 arranged on the first lubrication hole 44. The first lubrication hole 44 passes through the upper surface of the cylinder assembly 40 and the first lubrication cavity 22. The first lubrication hole 44 is provided with an internal thread at the end of the upper surface of the cylinder assembly 40. The stud pipe 45 has a matching external thread and both ends of the stud channel are connected.

[0073] The first lubricating oil tank 34 is arranged at the top of the cylinder assembly 40, and the stud passages of the plurality of plunger pump units extend from the bottom of the first lubricating oil tank 34 into the first lubricating oil tank 34. Two nuts are arranged on the stud pipe 45, namely the first nut and the second nut. The first nut is arranged between the first lubricating oil tank 34 and the cylinder assembly 40, and the first nut is used to fix the position of the stud passage. A sealing ring 55 is arranged between the first nut and the cylinder assembly 40.

[0074] The second nut is used to fix the relative position of the stud pipe 45 and the first lubricating oil tank 34 , and a sealing ring 55 is provided between the second nut and the first lubricating oil tank 34 .

[0075] In some embodiments, Figure 7 , Fig.13 As shown, multiple first lubrication cavities 22 are connected to the first lubrication oil tank 34 via a stud pipe 45, and longitudinal pipes 68 and transverse pipes 69 are also provided inside the cylinder body 10. Each lubrication cavity is connected to a longitudinal pipe 68 respectively, and the transverse pipe 69 connects multiple longitudinal pipes 68. The stud pipe 45 is connected to the transverse pipe 69, and the lubrication oil in the first lubrication oil tank 34 can flow into each first lubrication cavity 22 through the stud pipe 45, the transverse pipe 69, and the longitudinal pipe 68.

[0076] In order to facilitate the processing of the longitudinal pipe 68 and the transverse pipe 69, the longitudinal pipe 68 is drilled from the outside to the inside of the cylinder body 10, and a plug 43 is provided at one end of the longitudinal pipe 68 outside the cylinder body 10 to block the end of the longitudinal pipe 68 on the surface of the cylinder body 10. The transverse pipe 69 runs through the cylinder body 10, and plugs 43 for blocking are provided at both ends of the transverse pipe 69.

[0077] In this embodiment, the first lubrication channels of the plurality of plunger pump units are connected to the same first lubrication oil tank 34. Since the first lubrication oil tank 34 can be sealed and has airtightness, when the plunger of a plunger pump unit moves in the second direction, the pressure of the first lubrication cavity 22 increases, and the pressure can assist in pumping the lubrication oil into the first lubrication cavity 22 of another plunger pump unit whose plunger is moving in the first direction. When the plungers of the plurality of plunger pump units move back and forth, the plunger bodies 12 can provide each other with power to assist the flow of the lubrication oil.

[0078] Furthermore, the bidirectional piston pump also includes an input pressure sensor connected to the total input channel 41, an output pressure sensor connected to the total output channel 42, a flow sensor 52 connected to the total input channel 41 or the total output channel 42, a motor for driving the crankshaft 35 to rotate, a frequency converter and a controller for controlling the motor; the controller is connected to the input pressure sensor, the flow sensor, the output pressure sensor and the frequency converter, and the controller is used to obtain signals from the input pressure sensor, the flow sensor 52 and the output pressure sensor and to adjust the working parameters of the frequency converter.

[0079] In this embodiment, the frequency converter controls the speed and torque of the motor by adjusting the output frequency and voltage. The frequency converter can adjust the operating speed of the motor as needed, thereby achieving precise control of the motor. By changing the parameter settings of the frequency converter, different operating modes and control methods can be achieved to meet different application requirements. The frequency converter can also realize functions such as starting, stopping, accelerating, and decelerating to improve the operating efficiency and energy-saving performance of the motor. The motor is controlled by the frequency converter, which can control the output flow of the pump. A double-acting plunger pump in this embodiment can be connected to an information system, and the operating condition of the pump can be remotely monitored in real time and the machine can be turned on and off remotely through a cloud platform.

[0080] In some embodiments, a double-acting plunger pump also includes a PLC, which is a programmable logic controller, a special digital computer used in industrial control systems. PLC is mainly used to control various motions, logic and process controls in production lines, machinery and equipment, and industrial automation systems. PLC can control input and output devices according to pre-written programs to achieve automatic control and monitoring functions. PLC is connected to data acquisition modules such as input pressure sensor, flow sensor 52, and output pressure sensor through a 485 bus, collects various working parameters of the plunger pump, and pre-processes the data and transmits it to a data center. PLC is connected to an Internet of Things communication module, which is connected to a cloud platform server through a wireless network to achieve remote control of a double-acting plunger pump. PLC is connected to a frequency converter through a 485 bus, collects frequency converter operation data, pre-processes the data and transmits it to a data center, transmits various control instructions from the data center to the frequency converter, controls the motor operation state, and puts the plunger pump in an optimized working state. PLC can also be connected to a touch screen to achieve on-site human-computer interaction.

[0081] The present invention also provides a control method for a double-acting plunger pump, comprising: Obtain the target delivery capacity, which refers to the total volume of liquid delivered by the double-acting plunger pump during the working hours; Calculate the target output flow rate based on the target delivery capacity. The target output flow rate refers to the output liquid flow rate that the double-acting plunger pump needs to achieve; Obtaining the inlet pressure of the total input channel 41 of the two-way acting plunger pump, the outlet pressure of the total output channel 42 of the two-way acting plunger pump, and the actual output flow of the two-way acting plunger pump; Adjust the inverter operating parameters according to the target output flow, actual output flow, inlet pressure and outlet pressure.

[0082] The control method of this embodiment is suitable for a double-acting plunger pump to output high-pressure liquid for water well injection. The target delivery capacity can be, for example, 50m3 per day. 3 The output water pressure is 27 MPa, and the target output flow rate is calculated based on the target delivery capacity. The target output flow rate of this embodiment can be 35L per minute.

[0083] During operation, the double-acting piston pump continuously collects data from the input pressure sensor, flow sensor 52, and output pressure sensor, analyzes whether the output pressure and output flow meet the requirements, and can dynamically generate the inverter working parameters according to the output flow and input pressure to achieve energy consumption reduction while completing the water injection task.

[0084] In some embodiments, working time refers to a specific working time period, which may be one day, one week, one month, or other time periods.

[0085] The various embodiments disclosed in the present invention have been described above. The above description is exemplary and not exhaustive, and the scope of the present invention is not limited to the above embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the spirit and scope of the present invention. In other words, those of ordinary skill in the art can make various changes and improvements to the present invention in form and detail, and these are considered to fall within the scope of protection of the present invention. The choice of terms used herein is intended to best explain the principles of the various embodiments, practical applications, or improvements to the technology in the market, or to enable those of ordinary skill in the art to understand the various embodiments disclosed herein.

Claims

1. A double-acting plunger pump for increasing liquid pressure, characterized in that: The double-acting plunger pump comprises at least one plunger pump unit, which comprises a cylinder (10), a plunger, and a transmission device for driving the plunger to move; the plunger comprises a plunger head (11), a plunger body (12), and a connector (13); the cylinder (10) comprises a first compression chamber (14) whose size matches that of the plunger head (11), and a second compression chamber (15) whose size matches that of the plunger body (12); the first compression chamber (14) is provided with a first input port (16) and a first output port (17), the second compression chamber (15) is provided with a second input port (18) and a second output port (19), and the first input port (16), the first output port (17), the second input port (18), and the second output port (19) are respectively provided with a one-way valve; the connector (13) passes through the end of the cylinder (10) and is connected to the transmission device; The transmission device is capable of driving the plunger to reciprocate. When the plunger moves in a first direction, the plunger head (11) moves in the first compression chamber (14) to generate negative pressure, and the liquid input into the cylinder body (10) flows into the first compression chamber (14) from the first input port (16), while using the energy of the incoming water to perform work; the plunger body (12) moves in the second compression chamber (15) to generate positive pressure, and the liquid in the second compression chamber (15) flows out of the cylinder body (10) from the second output port (19); When the plunger moves in the second direction, the plunger head (11) moves in the first compression chamber (14) to generate positive pressure, and the liquid in the first compression chamber (14) flows out of the cylinder body (10) from the first output port (17); the plunger body (12) moves in the second compression chamber (15) to generate negative pressure, and the liquid input into the cylinder body (10) flows into the second compression chamber (15) from the second input port (18), and work is performed using the energy of the incoming water.

2. A double-acting plunger pump according to claim 1, characterized in that: The plunger surface areas on the plunger head (11) and the plunger body (12) for pushing the liquid to flow under pressure are equal.

3. A double-acting plunger pump according to claim 1, characterized in that: The inner wall of the cylinder body (10) in contact with the plunger head (11) is provided with a first sealing component (31), the inner wall of the cylinder body (10) in contact with the plunger body (12) is provided with a second sealing component (32), and the inner wall of the cylinder body (10) in contact with the connecting head (13) is provided with a third sealing component (33); The first sealing assembly (31), the second sealing assembly (32), and the third sealing assembly (33) are used to prevent leakage of liquid inside the cylinder body (10).

4. A double-acting plunger pump according to claim 3, characterized in that: The first sealing assembly (31) and / or the second sealing assembly (32) and / or the third sealing assembly (33) comprises a sealing ring groove arranged on the inner wall of the cylinder body (10) and a Y-shaped sealing ring arranged in the sealing ring groove, wherein the Y-shaped sealing ring has a wear compensation function.

5. A double-acting plunger pump according to claim 3, characterized in that: The cylinder body (10) further comprises a first lubricating cavity (22) having a size matching that of the plunger body (12); a first lubricating oil tank (34) is arranged outside the cylinder body (10); a first lubricating channel is arranged inside the first lubricating oil tank (34) and the cylinder body (10); the first lubricating channel is used to transport lubricating oil to the first lubricating cavity (22); When the plunger moves in a first direction, the plunger body (12) moves in the first lubricating cavity (22) to generate negative pressure, and the lubricating oil in the first lubricating oil tank (34) flows into the first lubricating cavity (22) through the first lubricating passage; when the plunger moves in a second direction, the plunger body (12) moves in the first lubricating cavity (22) to generate positive pressure, and the lubricating oil in the first lubricating cavity (22) flows into the first lubricating oil tank (34) through the first lubricating passage; The lubricating oil in the first lubricating cavity (22) can adhere to the outer surface of the plunger head (11), the outer surface of the plunger body (12) and the inner surface of the cylinder body (10); When the plunger moves back and forth, the lubricating oil in the first lubricating cavity (22) can delay the wear of the first sealing component (31) and the second sealing component (32), thereby extending the service life of the first sealing component (31) and the second sealing component (32).

6. A double-acting plunger pump according to claim 3, characterized in that: The contact portion between the cylinder body (10) and the connecting head (13) further comprises an annular extension portion (63), and the connecting head (13) passes through the extension portion (63); a third sealing groove (65) is provided on the inner wall of the extension portion (63), and the third sealing assembly (33) is arranged in the third sealing groove (65); A second lubricating cavity (26) is provided in the radial direction inside the extension portion (63), and the second lubricating cavity (26) is connected to the third sealing groove (65); the second lubricating cavity (26) can be filled with lubricating oil, and the lubricating oil in the second lubricating cavity (26) can delay the wear of the third sealing assembly (33) to extend the service life of the third sealing assembly (33).

7. A double-acting plunger pump according to claim 1, characterized in that: The plunger surface has a PEEK self-lubricating material layer.

8. A double-acting plunger pump according to any one of claims 1 to 7, characterized in that: The bidirectional piston pump comprises a plurality of piston pump units; the transmission device comprises a crankshaft (35) and a connecting rod (36) connecting the crankshaft (35) and the piston; the number of the connecting rods (36) is consistent with the number of the piston pump units, the plurality of connecting rods (36) are respectively connected to the connecting heads (13) of the plurality of piston pump units, and the angles of the plurality of connecting rods (36) are evenly distributed in the circumferential direction of the crankshaft (35).

9. A double-acting plunger pump according to claim 8, characterized in that: The bidirectional piston pump comprises three piston pump units; the transmission device comprises three connecting rods (36), one end of the three connecting rods (36) is respectively connected to the crankshaft (35), and the other end is connected to the connecting heads (13) respectively connected to the three piston pump units; the angles of the three connecting rods (36) are evenly distributed in the circumferential direction of the crankshaft (35).

10. A double-acting plunger pump according to claim 9, characterized in that: The cylinder bodies (10) of the three plunger pump units form a cylinder body assembly (40), and the cylinder body assembly (40) is provided with a total input channel (41) and a total output channel (42); the total input channel (41) is connected to the first input port (16) and the second input port (18) of the three plunger pump units; and the total output channel (42) is connected to the first output port (17) and the second output port (19) of the three plunger pump units.

11. A double-acting plunger pump according to claim 10, characterized in that: The bidirectional piston pump further comprises an input pressure sensor connected to the total input channel (41), an output pressure sensor connected to the total output channel (42), a flow sensor connected to the total input channel (41) or the total output channel (42), a motor for driving the crankshaft (35) to rotate, a frequency converter for controlling the motor, and a controller; the controller is connected to the input pressure sensor, the output pressure sensor, the flow sensor, and the frequency converter, and is used to obtain signals from the input pressure sensor, the flow sensor, and the output pressure sensor, and to adjust operating parameters of the frequency converter.

12. A control method for a double-acting piston pump according to any one of claims 1 to 11, characterized in that: include: Obtain the target delivery capacity, which refers to the total volume of liquid delivered by the double-acting plunger pump during the working hours; Calculate the target output flow rate based on the target delivery capacity. The target output flow rate refers to the output liquid flow rate that the double-acting plunger pump needs to achieve; Obtaining the inlet pressure of the total input channel (41) of the two-way acting plunger pump, the outlet pressure of the total output channel (42) of the two-way acting plunger pump, and the actual output flow rate of the two-way acting plunger pump; Adjust the inverter operating parameters according to the target output flow, actual output flow, inlet pressure and outlet pressure.

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