A four-piston pump

Abstract

This invention belongs to the field of liquid pump technology, specifically referring to a four-plunger pump, including a pump body, a pump head, and plungers. The pump head has an inlet and an outlet, and also includes an inlet chamber, a water collection channel, and a pressure regulating valve orifice. The outlet and the pressure regulating valve orifice are connected via an unloading drive channel. One end of the water collection channel is open, and a shut-off valve is located at the opening. A microswitch is located at the outer end of the shut-off valve stem. The shut-off drive chamber of the shut-off valve is connected to the outlet via a shut-off drive channel. A return water channel is also provided within the pump head, and the pressure regulating valve controls the connection and disconnection between the return water channel and the water collection channel. This invention features shut-off operation, reducing unnecessary energy consumption and component wear. It also eliminates the need for an external return water pipe, effectively reducing the number of pipe fittings and assembly steps, resulting in low manufacturing costs. Furthermore, its compact structure and small overall size meet the industry's demand for miniaturized and low-cost plunger pumps.

Description

Technical Field

[0001] This invention belongs to the field of liquid pump technology, specifically referring to a four-plunger pump. Background Technology

[0002] Chinese invention patent (publication number CN120701562A, application date 2025.07.31, publication date 2025.09.26) discloses a plunger pump, including a pump body, a pump head, and plungers. The pump head has an inlet hole and an outlet hole. Four plunger holes are arranged in a matrix inside the pump head. The plungers are driven by a driving mechanism to reciprocate within the plunger holes. An inlet check valve is provided in each of the four plunger holes. An outlet pipe communicating with the corresponding plunger hole is provided on the pump head next to each plunger hole. A first outlet check valve is provided in the outlet pipe. A water collection channel is also provided inside the pump head. The pump head is connected to each outlet pipe via a connecting hole. The first outlet check valve controls the opening and closing of the plunger hole and the water collection channel. The outlet hole is connected to the water collection channel, and a second outlet check valve is installed on the outlet hole. The pump head is also equipped with a return water channel and a pressure regulating valve hole, which are connected to the water collection channel. A pressure regulating valve is installed in the pressure regulating valve hole, which controls the opening and closing of the return water channel and the water collection channel. The outlet hole and pressure regulating valve hole are obliquely arranged on the pump head and are distributed in a figure-eight shape. The outer ends of the second outlet check valve and the pressure regulating valve extend outside the pump head and are located on both sides of the inlet hole. The outlet pressure can be adjusted by the pressure regulating valve. When the pressure inside the pump head is greater than the threshold pressure, the valve core of the pressure regulating valve can be opened appropriately, allowing water exceeding the threshold to overflow into the return water channel for discharge. The outlet hole and the pressure regulating valve hole are connected by an unloading drive channel. When the pump is turned off, the external... Maintain high-pressure water. The high-pressure water passes through the second outlet check valve and the unloading drive channel to fully open the pressure regulating valve, so that there is no water blocking the return flow channel outside the pump, thus achieving the unloading function.

[0003] The shortcomings of the above-mentioned plunger pump are: 1. The plunger pump only has the function of unloading and stabilizing pressure, and does not have the function of automatic shut-off. The motor continues to run when the pump is shut off and unloaded, resulting in unnecessary energy consumption and component wear; 2. The return water channel requires an external return water pipe, which adds extra pipeline accessories and assembly processes, significantly increasing the manufacturing cost. In addition, the overall size is large, which cannot meet the current industry development needs of miniaturization and low cost of plunger pumps. Summary of the Invention

[0004] The purpose of this invention is to provide a four-plunger pump that features shut-off when the plunger is turned off, reducing unnecessary energy consumption and component wear. It also eliminates the need for an external return water pipe, effectively reducing the number of pipe fittings and assembly steps, resulting in low manufacturing costs. Furthermore, it has a compact structure and small overall size, which can meet the industry's development needs for miniaturization and low cost of plunger pumps.

[0005] This invention is implemented as follows: A four-plunger pump includes a pump body, a pump head, and plungers. The pump head has an inlet and an outlet. Four plunger holes are arranged in a matrix inside the pump head. The plungers are driven by a drive mechanism to reciprocate within the plunger holes. An outlet pipe communicating with the corresponding plunger hole is provided on the pump head beside each plunger hole. The pump head also includes an inlet chamber communicating with the inlet hole, a water collection channel communicating with the outlet hole, and a pressure regulating valve hole communicating with the water collection channel. The water collection channel is connected to each outlet pipe through a connecting hole. A one-way outlet valve is provided on the outlet hole. Valve 1 has a pressure regulating valve installed in the pressure regulating valve hole. The outlet hole and the pressure regulating valve hole are connected through an unloading drive channel. One end of the water collection channel is open, and a shut-off valve is installed at the opening. A micro switch for controlling the start and stop of the four-plunger pump is installed at the outer end of the shut-off valve stem of the shut-off valve. The shut-off drive chamber of the shut-off valve is connected to the outlet hole through a shut-off drive channel. The pump head also has a return water channel 1 that connects the inlet chamber and the pressure regulating valve hole. The pressure regulating valve controls the opening and closing of the return water channel 1 and the water collection channel.

[0006] In the aforementioned four-plunger pump, an inlet check valve is provided in each of the four plunger holes, and an outlet check valve is provided in the outlet pipeline. The outlet check valve controls the opening and closing of the plunger holes and the water collection channel.

[0007] In the aforementioned four-plunger pump, a microswitch can be directly connected to the power supply line of the four-plunger pump via a wire. Alternatively, the microswitch can be connected to a microcontroller, which can then control the operation of the four-plunger pump.

[0008] In the aforementioned four-plunger pump, the shut-off valve further includes a shut-off valve seat disposed at the opening of the water collection channel. An mounting base is provided inside the shut-off valve seat, and a movable cavity is formed between the shut-off valve seat and the mounting base for the inner end of the shut-off valve stem to slide. A sealing ring is fitted onto the inner end of the shut-off valve stem, dividing the movable cavity into a shut-off drive cavity and a balance cavity. A spring is installed in the balance cavity, causing the shut-off valve stem to move outwards. The balance cavity is connected to the water collection channel. The outer end of the mounting base is disposed inside the shut-off valve seat, and a gap is left between the two to connect the shut-off drive cavity and the shut-off drive channel.

[0009] In the aforementioned four-plunger pump, a housing is installed on the outer end of the shut-off valve seat, and the micro switch is installed inside the housing.

[0010] In the aforementioned four-plunger pump, the sealing ring is an O-ring.

[0011] In the aforementioned four-plunger pump, the shut-off valve stem is a stepped shaft, comprising a large-diameter section and a small-diameter section located at the outer end of the large-diameter section. The small-diameter section is equipped with a micro switch at its outer end. The outer wall of the large-diameter section is recessed to form an annular groove. A sealing ring is disposed within the annular groove. A fixing plate is provided at the inner end of the mounting base. A spring is disposed between the fixing plate and the inner end face of the large-diameter section. The fixing plate is provided with a through hole connecting the balance chamber and the water collection channel.

[0012] In the aforementioned four-plunger pump, the shut-off valve seat is provided with a stepped hole, including a large hole, a medium hole, and a small hole arranged sequentially from the inside to the outside. An O-ring is provided between the small diameter section and the shut-off valve seat, fitted outside the small diameter section and located inside the small hole. A limiting block is fitted outside the small diameter section to axially limit the O-ring. The limiting block is located inside the medium hole and abuts against the stepped surface of the medium hole for limiting. The outer end of the mounting base is located inside the large hole.

[0013] In the aforementioned four-plunger pump, the outer end of the water collection channel is a stepped hole, including a large hole II, a medium hole II, and a small hole II arranged sequentially from the outside to the inside. The medium hole II is a threaded hole, and the shut-off valve seat is screwed to the medium hole II. An O-ring is provided between the shut-off valve seat and the large hole II, which is fitted onto the shut-off valve seat. The outer wall of the mounting base protrudes outward to form a limiting flange provided in the small hole II. The limiting flange abuts against the stepped surface of the small hole II for limiting. An O-ring is provided between the mounting base and the water collection channel, which is fitted onto the outside of the mounting base and located inside the limiting flange.

[0014] In the aforementioned four-plunger pump, the water outlet and pressure regulating valve orifice are obliquely arranged on the pump head, and the water outlet and pressure regulating valve orifice are distributed in a figure-eight shape. The outer ends of the water outlet check valve and the pressure regulating valve extend outside the pump head and are located on both sides of the water inlet. The water collection channel is located in the center of the matrix, and the shut-off valve is located between the two water outlet pipes on one side of the water outlet check valve.

[0015] In the aforementioned four-plunger pump, the pump head is also provided with an easy-start valve hole. The easy-start valve hole is connected to the water collection channel through the water passage and the easy-start valve hole is connected to the water inlet chamber through the second return water channel. An easy-start valve is provided in the easy-start valve hole, and the easy-start valve controls the opening and closing of the water passage and the second return water channel.

[0016] In the aforementioned four-plunger pump, the easy-start valve includes an easy-start valve seat fixedly installed in the easy-start valve hole and an easy-start valve core slidably disposed in the easy-start valve hole. The easy-start valve seat is provided with a water passage hole one that is closed at the outer end and open at the inner end. The side wall of the easy-start valve seat is provided with a water passage hole two that connects a return water channel two with the water passage hole one. The easy-start valve core is fitted with a sealing ring two for sealing the inner end of the water passage hole one. The water passage hole one is provided with a spring two that has elasticity to move the easy-start valve core inward.

[0017] In the aforementioned four-plunger pump, two O-rings are provided between the easy-start valve seat and the easy-start valve hole, with the O-rings fitted outside the easy-start valve seat, and the water passage hole two is located between the two O-rings.

[0018] In the aforementioned four-plunger pump, the easy-start valve orifice is located below the water collection channel and between the two plunger orifices. The water outlet pipe is perpendicular to the axis of the plunger orifice, and the axes of the water collection channel and the water outlet pipe are parallel to each other. The axis of the easy-start valve orifice is perpendicular to the axes of the water collection channel and the plunger orifice, respectively.

[0019] In the aforementioned four-plunger pump, the outlet hole is a stepped hole, including a small hole section and a large hole section located outside the small hole section. The outlet one-way valve includes an outlet one-way valve seat fixedly installed in the large hole section and an outlet one-way valve core slidably installed in the large hole section. The outlet one-way valve core is fitted with a sealing ring three for sealing the outer end of the small hole section. The outlet one-way valve seat is provided with a spring three that has elasticity to move the outlet one-way valve core inward. The unloading drive channel and the shutdown drive channel are both connected to the large hole section.

[0020] In the aforementioned four-plunger pump, the outlet check valve seat and the outlet check valve core are respectively provided with stepped holes, and one end of the spring is set in the stepped hole of the outlet check valve seat and the other end is set in the stepped hole of the outlet check valve core.

[0021] In the aforementioned four-plunger pump, the pump head includes a pump head body and a pump cover covering the pump head body. The pump head body and the pump cover form the water inlet chamber, and the water inlet hole is provided on the pump cover.

[0022] The outstanding advantages of this invention compared to the prior art are: This invention features a shut-off valve at one end of the water collection channel and a microswitch at the outer end of the shut-off valve stem to control the start and stop of the four-plunger pump, thus achieving shut-off and reducing unnecessary energy consumption and component wear. The design is ingenious and compact. Furthermore, the pump head includes a return water channel connecting the inlet chamber and the pressure regulating valve hole, allowing water to flow back from the return water channel inside the pump head to the inlet chamber without the need for an external return water pipe. This effectively reduces the need for pipe fittings and assembly processes, resulting in low manufacturing costs. The compact structure and small overall size meet the industry's demand for miniaturized and low-cost plunger pumps. Attached Figure Description

[0023] Figure 1 This is a perspective view of the present invention.

[0024] Figure 2 This is the front view of the present invention.

[0025] Figure 3 yes Figure 2 AA sectional view.

[0026] Figure 4 yes Figure 3 Enlarged view of point I.

[0027] Figure 5 yes Figure 2 BB cross-sectional view.

[0028] Figure 6 yes Figure 2 CC section view.

[0029] Figure 7 This is a perspective view of the pump head body of the present invention.

[0030] Figure 8 This is a front view of the pump head body of the present invention.

[0031] Figure 9 yes Figure 8 DD sectional view.

[0032] Reference numerals: 1. Pump body; 2. Pump head; 3. Plunger; 4. Inlet hole; 5. Outlet hole; 5a. Small orifice section; 5b. Large orifice section; 6. Plunger hole; 7. Outlet pipe; 8. Inlet chamber; 9. Water collection channel; 10. Pressure regulating valve hole; 11. Connecting hole; 12. Outlet check valve one; 12a. Outlet check valve seat; 12b. Outlet check valve core; 12c. Sealing ring three; 12d. Spring three; 13. Pressure regulating valve; 14. Unloading drive channel; 15. Shutdown valve; 15a. Shutdown valve stem; 15b. Shutdown valve seat; 15c. Mounting base; 15d. 15e. Sealing ring 1; 16. Fixing plate; 17. Micro switch; 18. Stop drive chamber; 19. Stop drive channel; 20. Return water channel 1; 21. Balance chamber; 22. Spring 1; 23. Annular groove; 24. Easy-start valve hole; 25. Water passage; 26. Return water channel 2; 26. Easy-start valve; 26a. Easy-start valve seat; 26b. Easy-start valve core; 26c. Sealing ring 2; 26d. Spring 2; 27. Water passage hole 1; 28. Water passage hole 2; 29. ​​Inlet check valve; 30. Outlet check valve 2; 31. Housing; 32. Limiting block; 33. Limiting flange. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments. See also: Figure 1 —9: A four-plunger pump includes a pump body 1, a pump head 2, and plungers 3. The pump head 2 has an inlet hole 4 and an outlet hole 5. Four plunger holes 6 are arranged in a matrix inside the pump head 2. The plungers 3 are driven by a drive mechanism to reciprocate within the plunger holes 6. An outlet pipe 7 is provided on the side of each plunger hole 6, communicating with the corresponding plunger hole 6. The pump head 2 also has an inlet chamber 8 communicating with the inlet hole 4, a water collection channel 9 communicating with the outlet hole 5, and a pressure regulating valve hole 10 communicating with the water collection channel 9. The water collection channel 9 is connected to each outlet pipe 7 through a connecting hole 11. A one-way valve 12 is provided on each outlet hole 5. A pressure regulating valve 13 is installed inside the pressure regulating valve hole 10. The outlet hole 5 is connected to the pressure regulating valve hole 10 through an unloading drive channel 14. One end of the water collection channel 9 is open, and a shut-off valve 15 is installed at the opening. A micro switch 16 for controlling the start and stop of the four-plunger pump is installed at the outer end of the shut-off valve stem 15a of the shut-off valve 15. The shut-off drive chamber 17 of the shut-off valve 15 is connected to the outlet hole 5 through a shut-off drive channel 18. The pump head 2 is also provided with a return water channel 19 that connects the inlet chamber 8 and the pressure regulating valve hole 10. The pressure regulating valve 13 controls the opening and closing of the return water channel 19 and the water collection channel 9.

[0034] In the aforementioned four-plunger pump, an inlet check valve 29 is provided in each of the four plunger holes 6, and an outlet check valve 30 is provided in the outlet pipeline 7. The outlet check valve 30 controls the opening and closing of the plunger holes 6 and the water collection channel 9.

[0035] In the aforementioned four-plunger pump, the micro switch 16 can be directly connected to the power supply line of the four-plunger pump via a wire.

[0036] The working principle of this invention is as follows: Figure 1-9 As shown, when the four-plunger pump is running normally, water flows out through the inlet hole 4, inlet chamber 8, plunger hole 6, outlet pipe 7, connecting hole 11, and water collection channel 9, and then flows out through the outlet hole 5. At this time, the shut-off valve stem 15a contacts the contact of the micro switch 16, and the micro switch 16 controls the four-plunger pump to be in the open state.

[0037] When the four-plunger pump is in normal use, but the pressure inside the pump head 2 is greater than the threshold pressure, the high-pressure water pushes the pressure regulating valve 13 to open moderately through the unloading drive channel 14, so that the water above the threshold overflows into the return water channel 19 and returns to the inlet chamber 8.

[0038] When the pump is shut off, the outlet check valve 12 closes the outlet hole 5, and high-pressure water is maintained externally. The high-pressure water enters the shutdown drive chamber 17 through the unloading drive channel 14. The shut-off valve stem 15a does not contact the contacts of the micro switch 16. The contacts of the micro switch 16 are reset outward under the action of the internal elastic element. The micro switch 16 controls the four-plunger pump to stop, realizing the shutdown of the pump. At the same time, the high-pressure water pushes the pressure regulating valve 13 to open through the unloading drive channel 14. The water in the water collection channel 9 returns to the inlet chamber 8 through the pressure regulating valve hole 10 and the return water channel 19, realizing the return of water in the pump to the inlet chamber 8, thus realizing the unloading function.

[0039] This invention features a shut-off valve 15 at one end of the water collection channel 9, and a microswitch 16 controlling the start and stop of the four-plunger pump is installed at the outer end of the shut-off valve stem 15a of the shut-off valve 15, achieving shut-off and stopping, reducing unnecessary energy consumption and component wear, and the structure is ingenious and compact. In addition, the pump head 2 is also provided with a return water channel 19 connecting the water inlet chamber 8 and the pressure regulating valve hole 10, so that water flows back from the return water channel 19 inside the pump head 2 to the water inlet chamber 8, eliminating the need for an external return water pipe, effectively reducing pipeline fittings and assembly processes, resulting in low manufacturing costs, a compact structure, and a small overall size, which can meet the industry's development needs for miniaturization and low cost of plunger pumps.

[0040] Compared to plunger pumps that stop without a pump nozzle, if internal return water is used, the water temperature inside the pump will continuously rise, thus affecting the service life of the plunger pump.

[0041] The specific structure of the gun shut-off valve 15 is as follows: Figure 3 , 4 As shown in Figures 7-9, the shut-off valve 15 also includes a shut-off valve seat 15b disposed at the opening of the water collection channel 9. A mounting seat 15c is disposed inside the shut-off valve seat 15b. A movable cavity is formed between the shut-off valve seat 15b and the mounting seat 15c for the inner end of the shut-off valve rod 15a to slide. A sealing ring 15d is fitted on the inner end of the shut-off valve rod 15a. The sealing ring divides the movable cavity into the shut-off drive cavity 17 and the balance cavity 20. A spring 21 is installed in the balance cavity 20, which has elasticity to move the shut-off valve rod 15a outward. The balance cavity 20 is connected to the water collection channel 9. The outer end of the mounting seat 15c is disposed inside the shut-off valve seat 15b, and a gap is left between the two to connect the shut-off drive cavity 17 and the shut-off drive channel 18.

[0042] When the four-plunger pump is in normal use, the water in the water collection channel 9 enters the balance chamber 20. The shut-off valve stem 15a moves outward under the elastic force of the spring-21 and the water pressure in the balance chamber 20, and abuts against the contact of the micro switch 16. When the four-plunger pump shuts off, high-pressure water enters the shut-off drive chamber 17 through the shut-off drive channel 18, pushing the shut-off valve stem 15a to compress the spring-21 and move inward, leaving the contact of the micro switch 16.

[0043] The installation structure of the micro switch 16: a housing 31 is installed on the outer end of the shut-off valve seat 15b, and the micro switch 16 is installed inside the housing 31.

[0044] Furthermore, the sealing ring 15d is an O-ring.

[0045] The specific structure of the shut-off valve stem 15a and the mounting structure of spring 21 are as follows: Figure 3 , 4 As shown, the shut-off valve stem 15a is a stepped shaft, including a large-diameter section and a small-diameter section located at the outer end of the large-diameter section. The micro switch 16 is provided at the outer end of the small-diameter section. The outer side wall of the large-diameter section is recessed to form an annular groove 22. The sealing ring 15d is provided in the annular groove 22. The mounting base 15c is provided with a fixing plate 15e at its inner end. The spring 21 is provided between the fixing plate 15e and the inner end face of the large-diameter section. The fixing plate 15e is provided with a through hole connecting the balance chamber 20 and the water collection channel 9.

[0046] The sealing structure between the shut-off valve seat 15b and the shut-off valve stem 15a is as follows: Figure 3 , 4 As shown, the shut-off valve seat 15b has a stepped hole, including a large hole, a medium hole, and a small hole arranged sequentially from the inside to the outside. An O-ring is provided between the small diameter section and the shut-off valve seat 15b, which is fitted outside the small diameter section and located inside the small hole. A limiting block 32 is fitted outside the small diameter section to axially limit the O-ring. The limiting block 32 is located inside the medium hole and abuts against the stepped surface of the medium hole. The outer end of the mounting base 15c is located inside the large hole.

[0047] The mounting structure of the shut-off valve seat 15b and mounting base 15c is as follows: Figure 3 , 4As shown, the outer end of the water collection channel 9 is a stepped hole, including a large hole two, a medium hole two, and a small hole two arranged sequentially from the outside to the inside. The medium hole two is a threaded hole. The shut-off valve seat 15b is screwed to the medium hole two. An O-ring is provided between the shut-off valve seat 15b and the large hole two and fitted on the shut-off valve seat 15b. The outer side wall of the mounting base 15c protrudes to form a limiting flange 33 set in the small hole two. The limiting flange 33 abuts against the stepped surface of the small hole two and limits its movement. An O-ring is provided between the mounting base 15c and the water collection channel 9, fitted on the outside of the mounting base 15c and located inside the limiting flange 33.

[0048] Furthermore, the water outlet 5 and the pressure regulating valve hole 10 are obliquely arranged on the pump head 2, and the water outlet 5 and the pressure regulating valve hole 10 are distributed in a figure-eight shape. The outer ends of the water outlet check valve 12 and the pressure regulating valve 13 extend out of the pump head 2 and are located on both sides of the water inlet hole 4. The water collection channel 9 is located in the center of the matrix. The shut-off valve 15 is located between the two water outlet pipes 7 on one side of the water outlet check valve 12. The structure is compact.

[0049] In order to extend the service life of the motor, such as Figure 2 , 4 As shown in Figures 7-9, the pump head 2 is also provided with an easy-start valve hole 23. The easy-start valve hole 23 is connected to the water collection channel 9 through the water passage 24 and to the water inlet chamber 8 through the second return water passage 25. An easy-start valve 26 is provided in the easy-start valve hole 23, which controls the opening and closing of the water passage 24 and the second return water passage 25. During the start-up phase of the four-plunger pump, the high-pressure water in the water collection channel 9 enters the easy-start valve hole 23 through the water passage 24 and returns to the water inlet chamber 8 through the second return water passage 25, effectively reducing the torque during the motor start-up phase. After the four-plunger pump starts, the high-pressure water in the water collection channel 9 passes through the water passage to the easy-start valve hole 23 and then closes the easy-start valve 26.

[0050] The specific structure of the easy-start valve 26 is as follows: As shown in the figure, the easy-start valve 26 includes an easy-start valve seat 26a fixedly installed in the easy-start valve hole 23 and an easy-start valve core 26b slidably installed in the easy-start valve hole 23. The easy-start valve seat 26a is provided with a water passage hole 27 with the outer end closed and the inner end open. The side wall of the easy-start valve seat 26a is provided with a water passage hole 28 that connects the return water channel 25 and the water passage hole 27. The easy-start valve core 26b is fitted with a sealing ring 26c for sealing the inner end of the water passage hole 27. The water passage hole 27 is provided with a spring 26d that has elasticity to make the easy-start valve core 26b move inward.

[0051] Furthermore, two O-rings are provided between the easy-start valve seat 26a and the easy-start valve hole 23, and the water passage hole 28 is located between the two O-rings.

[0052] Location of easy-start valve port 23: as follows Figure 2 , 5 As shown, the easy-start valve hole 23 is located below the water collection channel 9 and between the two plunger holes 6. The water outlet pipe 7 is perpendicular to the axis of the plunger hole 6, and the water collection channel 9 is parallel to the axis of the water outlet pipe 7. The axis of the easy-start valve hole 23 is perpendicular to the axis of the water collection channel 9 and the axis of the plunger hole 6 respectively. The structure is compact.

[0053] The specific structure and installation structure of the outlet check valve 12: as follows Figure 1-3 As shown in Figures 7-9, the water outlet 5 is a stepped hole, including a small hole section 5a and a large hole section 5b located outside the small hole section 5a. The water outlet one-way valve 12 includes a water outlet one-way valve seat 12a fixedly installed in the large hole section 5b and a water outlet one-way valve core 12b slidably installed in the large hole section 5b. The water outlet one-way valve core 12b is fitted with a sealing ring 12c for sealing the outer end of the small hole section 5a. The water outlet one-way valve seat 12a is provided with a spring 12d that has elasticity to move the water outlet one-way valve core 12b inward. The unloading drive channel 14 and the shutdown drive channel 18 are both connected to the large hole section 5b.

[0054] The installation structure of spring 3 12d: The valve seat 12a and valve core 12b of the water outlet check valve are respectively provided with stepped holes. One end of spring 3 12d is set in the stepped hole of the valve seat 12a of the water outlet check valve, and the other end is set in the stepped hole of the valve core 12b of the water outlet check valve.

[0055] The structure of the pump head 2: The pump head 2 includes a pump head body and a pump cover on the pump head body. The pump head body and the pump cover form the water inlet chamber 8, and the water inlet hole 4 is provided on the pump cover.

[0056] The above embodiments are merely one of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, all equivalent changes made in accordance with the shape, structure and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A four-plunger pump, comprising a pump body (1), a pump head (2), and plungers (3), wherein the pump head (2) has an inlet hole (4) and an outlet hole (5), and four plunger holes (6) are arranged in a matrix inside the pump head (2). The plungers (3) are driven to reciprocate within the plunger holes (6) by a driving mechanism. An outlet pipe (7) communicating with the corresponding plunger hole (6) is provided on the pump head (2) beside each plunger hole (6). A pipe communicating with the inlet hole (4) is also provided inside the pump head (2). The water inlet chamber (8), the water collection channel (9) connecting the water outlet (5), and the pressure regulating valve hole (10) connecting the water collection channel (9) are connected to each water outlet pipe (7) through the connecting hole (11). A one-way valve (12) is provided on the water outlet (5), and a pressure regulating valve (13) is provided in the pressure regulating valve hole (10). The water outlet (5) and the pressure regulating valve hole (10) are connected through the unloading drive channel (14). The feature is that: One end of the water collection channel (9) is open, and a shut-off valve (15) is provided at the opening. A micro switch (16) for controlling the start and stop of the four-plunger pump is provided at the outer end of the shut-off valve stem (15a) of the shut-off valve (15). The shut-off drive chamber (17) of the shut-off valve (15) is connected to the outlet hole (5) through a shut-off drive channel (18). The pump head (2) is also provided with a return water channel (19) that connects the inlet chamber (8) and the pressure regulating valve hole (10). The pressure regulating valve (13) controls the opening and closing of the return water channel (19) and the water collection channel (9).

2. A four-plunger pump according to claim 1, characterized in that: The shut-off valve (15) also includes a shut-off valve seat (15b) located at the opening of the water collection channel (9). A mounting seat (15c) is provided on the inner side of the shut-off valve seat (15b). A movable cavity is formed between the shut-off valve seat (15b) and the mounting seat (15c) for the inner end of the shut-off valve rod (15a) to slide. A sealing ring (15d) is fitted on the inner end of the shut-off valve rod (15a). The sealing ring divides the movable cavity into the shut-off drive cavity (17) and the balance cavity (20). A spring (21) is installed in the balance cavity (20) to make the shut-off valve rod (15a) move outward. The balance cavity (20) is connected to the water collection channel (9). The outer end of the mounting seat (15c) is located in the shut-off valve seat (15b), and a gap is left between the two to connect the shut-off drive cavity (17) and the shut-off drive channel (18).

3. A four-plunger pump according to claim 2, characterized in that: The shut-off valve stem (15a) is a stepped shaft, including a large diameter section and a small diameter section located at the outer end of the large diameter section. The micro switch (16) is provided at the outer end of the small diameter section. The outer wall of the large diameter section is recessed to form an annular groove (22). The sealing ring (15d) is set in the annular groove (22). The mounting base (15c) is provided with a fixing plate (15e) at its inner end. The spring (21) is set between the fixing plate (15e) and the inner end face of the large diameter section. The fixing plate (15e) is provided with a through hole connecting the balance chamber (20) and the water collection channel (9).

4. A four-plunger pump according to claim 1, characterized in that: The water outlet (5) and pressure regulating valve (10) are obliquely arranged on the pump head (2), and the water outlet (5) and pressure regulating valve (10) are distributed in a figure-eight shape. The outer ends of the water outlet check valve (12) and pressure regulating valve (13) extend out of the pump head (2) and are located on both sides of the water inlet (4). The water collection channel (9) is located in the center of the matrix. The shut-off valve (15) is located between the two water outlet pipes (7) on one side of the water outlet check valve (12).

5. A four-plunger pump according to claim 1, characterized in that: The pump head (2) is also provided with an easy-start valve hole (23). The easy-start valve hole (23) is connected to the water collection channel (9) through the water passage (24). The easy-start valve hole (23) is connected to the water inlet chamber (8) through the return water channel (25). An easy-start valve (26) is provided in the easy-start valve hole (23). The easy-start valve (26) controls the opening and closing of the water passage (24) and the return water channel (25).

6. A four-plunger pump according to claim 5, characterized in that: The easy-start valve (26) includes an easy-start valve seat (26a) fixedly installed in the easy-start valve hole (23) and an easy-start valve core (26b) slidably installed in the easy-start valve hole (23). The easy-start valve seat (26a) is provided with a water passage hole (27) with the outer end closed and the inner end open. The side wall of the easy-start valve seat (26a) is provided with a water passage hole (28) connecting the return water channel (25) and the water passage hole (27). The easy-start valve core (26b) is fitted with a sealing ring (26c) for sealing the inner end of the water passage hole (27). The water passage hole (27) is provided with a spring (26d) that makes the easy-start valve core (26b) move inward due to elasticity.

7. A four-plunger pump according to claim 5, characterized in that: The easy-start valve hole (23) is located below the water collection channel (9) and between the two plunger holes (6). The water outlet pipe (7) is perpendicular to the axis of the plunger hole (6). The water collection channel (9) is parallel to the axis of the water outlet pipe (7). The axis of the easy-start valve hole (23) is perpendicular to the axis of the water collection channel (9) and the axis of the plunger hole (6).

8. A four-plunger pump according to claim 1, characterized in that: The outlet hole (5) is a stepped hole, including a small hole section (5a) and a large hole section (5b) located outside the small hole section (5a). The outlet one-way valve (12) includes an outlet one-way valve seat (12a) fixedly installed in the large hole section (5b) and an outlet one-way valve core (12b) slidably installed in the large hole section (5b). The outlet one-way valve core (12b) is fitted with a sealing ring three (12c) for sealing the outer end of the small hole section (5a). The outlet one-way valve seat (12a) is provided with a spring three (12d) that has elasticity to make the outlet one-way valve core (12b) move inward. The unloading drive channel (14) and the shutdown drive channel (18) are both connected to the large hole section (5b).

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