Plunger pump with high-pressure-maintaining overflow valve

Abstract

The utility model relates to the technical field of high-pressure cleaning machines, in particular to a plunger pump with a high-pressure-maintaining overflow valve. Comprising a pump cover and a pump body, a water inlet channel, a water outlet channel, an overflow channel and a main valve are arranged in the pump cover, the water outlet channel is communicated with the overflow channel, an overflow valve is arranged in the overflow channel, and a low-pressure one-way valve, a high-pressure one-way valve and a plunger cavity are arranged in the pump body. The plunger cavity is arranged between the low-pressure one-way valve and the high-pressure one-way valve, a plunger is arranged in the plunger cavity, a first communication cavity is arranged between the low-pressure one-way valve and the water inlet channel, a second communication cavity is arranged between the high-pressure one-way valve and the main valve, and the overflow channel is communicated with the first communication cavity through a first pressure relief hole. And the overflow channel is communicated with the second communication cavity through the second pressure relief hole. According to the plunger pump, when the water gun is closed, pressure relief can be conducted on water in the second communication cavity, then the overall performance of the plunger pump can be improved, and the service life of the plunger pump can be prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of high-pressure cleaners, in particular to a plunger pump with a high-pressure-holding overflow valve. Background Art

[0002] A high-pressure cleaner refers to a cleaning device that pressurizes water through a high-pressure water conversion device (generally a high-pressure plunger pump) through several levels to make its pressure reach more than several hundred atmospheric pressures, and then shoots it out through a high-pressure water gun.

[0003] The plunger pump is an important part of the high-pressure cleaner. The plunger pump includes a pump cover and a pump body. An inlet channel, an outlet channel, an overflow channel and a main valve are arranged on the pump cover. The outlet channel is communicated with the overflow channel, and an overflow valve is further arranged in the overflow channel. A low-pressure check valve, a high-pressure check valve and a plunger cavity are arranged in the pump body. A plunger is arranged in the plunger cavity. A first communication cavity is arranged between the low-pressure check valve and the inlet channel, and a second communication cavity is arranged between the high-pressure check valve and the main valve. And the overflow channel is communicated with the first communication cavity through a first pressure relief hole. In the prior art, when the water gun of the high-pressure cleaner is opened, the water flow direction is the inlet channel, the first communication cavity, the low-pressure check valve, the plunger cavity, the high-pressure check valve, the second communication cavity, the main valve and the outlet channel. When the water gun of the high-pressure cleaner is closed, at this time, the water pressure in the outlet channel is relatively high, the main valve will be closed and the overflow valve in the overflow channel will be opened at the same time, and then the water flow in the outlet channel will be guided to the inlet channel through the overflow channel and the first pressure relief hole to achieve pressure relief. However, when the water gun is closed, the water pressure in the second communication cavity is also relatively high, but the prior art cannot relieve the water pressure in this part, so it may affect the overall performance and service life of the plunger pump. Content of the Utility Model

[0004] The technical solution to be solved by the utility model is: to provide a plunger pump with a high-pressure-holding overflow valve, which can relieve the water pressure in the second communication cavity when the water gun is closed, thereby improving the overall performance and service life of the plunger pump.

[0005] The technical solution adopted by the utility model is: a plunger pump with a high-pressure-holding overflow valve, including a pump cover and a pump body. An inlet channel, an outlet channel, an overflow channel and a main valve are arranged in the pump cover. The outlet channel is communicated with the overflow channel, and an overflow valve is arranged in the overflow channel. A low-pressure check valve, a high-pressure check valve and a plunger cavity are arranged in the pump body. The plunger cavity is arranged between the low-pressure check valve and the high-pressure check valve. A plunger is arranged in the plunger cavity. A first communication cavity is arranged between the low-pressure check valve and the inlet channel, and a second communication cavity is arranged between the high-pressure check valve and the main valve. The overflow channel is communicated with the first communication cavity through a first pressure relief hole. The characteristic is that: the overflow channel is communicated with the second communication cavity through a second pressure relief hole.

[0006] When in the normal working state, the outlet of the water outlet channel is open, the main valve is opened, and the overflow valve is closed. At this time, the water flow in the second communication cavity flows out through the water outlet channel;

[0007] When in the gun - off and back - flushing state, the outlet of the water outlet channel is closed, the main valve is closed, the overflow valve is fully opened. The water flow in the second communication cavity is guided to the overflow channel through the second pressure - relief hole, and the water flow in the water outlet channel is guided to the first communication cavity and then to the water inlet channel through the overflow channel and the first pressure - relief hole;

[0008] When in the gun - off and standby - shutdown state, the outlet of the water outlet channel is closed, the main valve is closed, and the overflow valve is partially opened. At this time, the water outlet channel is separated from the first pressure - relief hole and the second pressure - relief hole.

[0009] Preferably, the overflow valve includes a valve cover, a valve core, a sealing ring, a push rod, a steel ball, a push rod seat, a spring, and a micro - switch. The push rod seat is arranged in the overflow channel, and a push - rod cavity and a push - rod chamber are arranged in the push rod seat. The push - rod cavity and the push - rod chamber are communicated through a communication hole. The first pressure - relief hole is communicated with the push - rod chamber, and the second pressure - relief hole is communicated with the push - rod cavity. The valve cover is arranged at the front end of the push rod seat, and a sealing ring is arranged between the valve cover and the push rod seat. The push rod is arranged in the push - rod cavity, the steel ball is arranged at the front end of the push rod, the micro - switch is located behind the push rod, and the spring is sleeved on the push rod and applies a thrust to the push rod.

[0010] When in the normal working state, the outlet of the water outlet channel is open, the main valve is opened, and the water pressure received on the valve core is less than the thrust applied by the spring. At this time, the micro - switch is in an untriggered state, the communication hole is sealed by the steel ball, so that the push - rod cavity is separated from the push - rod chamber, and the sealing ring is matched with the valve core for sealing, so that the water outlet channel is separated from the push - rod cavity;

[0011] When in the gun - off and back - flushing state, the outlet of the water outlet channel is closed, the main valve is closed, and the water pressure received on the valve core is greater than the thrust applied by the spring. At this time, the valve core, the push rod, the steel ball, and the push rod are pushed backward together. At this time, the micro - switch is in a triggered state, the communication hole is conducted, so that the push - rod cavity is conducted with the push - rod chamber, and the sealing ring is matched with the groove position on the valve core, so that the water outlet channel is conducted with the push - rod cavity;

[0012] When in the gun - off and standby - shutdown state, the outlet of the water outlet channel is closed, the main valve is closed, and the water pressure received on the valve core is less than the thrust applied by the spring. The valve core, the push rod, the steel ball, and the push rod are pushed forward together until the sealing ring is matched with the valve core for sealing, so that the water outlet channel is separated from the push - rod cavity. At this time, the micro - switch is still in a triggered state, the communication hole is still conducted, so that the push - rod cavity is conducted with the push - rod chamber.

[0013] Preferably, a stopper for the valve core to abut against is provided at a position of the ejector rod cavity close to the communication hole.

[0014] When in the gun-closing and back-flushing state, the valve core abuts against the stopper.

[0015] Preferably, three annular grooves are sequentially provided on the outer side of the push rod seat corresponding to the ejector rod cavity, namely a first annular groove, a second annular groove and a third annular groove. Sealing members are provided on both the first annular groove and the third annular groove. A first connection hole is provided at the bottom of the second annular groove, and the first connection hole communicates with the second pressure relief hole.

[0016] Preferably, one side wall of the second annular groove is inclined.

[0017] Preferably, a second connection hole is provided on the outer side of the push rod seat corresponding to the push rod cavity, and the second connection hole communicates with the first pressure relief hole.

[0018] Preferably, an installation cavity is provided on the pump cover. The main valve is installed in the installation cavity, and both the water outlet channel and the second communication cavity communicate with the installation cavity. When the main valve is opened, the second communication cavity communicates with the water outlet channel. When the main valve is closed, the second communication cavity is cut off from the water outlet channel.

[0019] Preferably, the main valve includes a plug. One side of the installation cavity communicates with the second communication cavity, and the other side of the installation cavity is sealed by the plug.

[0020] Preferably, a first circular closed loop, a second circular closed loop and a triangular closed loop are provided on the side of the pump cover close to the pump body. The first circular closed loop is provided on the outer ring of one side of the installation cavity. The second circular closed loop is sleeved outside the first circular closed loop. The triangular closed loop is sleeved outside the second circular closed loop. A first communication cavity is formed between the second circular closed loop and the triangular closed loop, and the first pressure relief hole is located between the second circular closed loop and the triangular closed loop. A second communication cavity is formed between the first circular closed loop and the second circular closed loop, and the second pressure relief hole is located between the first circular closed loop and the second circular closed loop.

[0021] Compared with the prior art by adopting the above structure, the utility model has the following advantages: A second pressure relief hole is provided. In this way, when the gun is closed, the water flow in the second communication cavity can be relieved through the second pressure relief hole, so that the pressure in the second communication cavity will be greatly reduced, improving the overall performance and service life of the plunger pump. Moreover, because the second pressure relief hole is provided, when in the gun-closing and holding-stop state, the water pressure in the second communication cavity will balance the water pressure in the water outlet channel together with the thrust of the spring, so that the thrust of the spring itself does not need to be very large, and thus the overall cost can be saved to a certain extent.

[0022] The overflow valve adopting this structure can well achieve three switching states, and the overall effect is good.

[0023] A blocking block is set. In this way, when in the state of gun closing and backwashing, the valve core abuts against the blocking block instead of directly against the communication hole, which can prevent the valve core from sealing the communication hole.

[0024] Sealed by two seals, so that the second pressure relief hole can be well sealed from other places and can only communicate with the ejector rod cavity through the first connection hole.

[0025] The wall of the second annular groove is inclined, so that the space between the first connection hole and the second pressure relief hole is larger, and thus better pressure relief can be achieved.

[0026] The second connection hole is set close to the communication hole, so that after the water flow passes through the communication hole, it can directly flow from the second connection hole into the first pressure relief hole for pressure relief, and the pressure relief speed is relatively fast.

[0027] The main valve is set in the installation cavity, which can well achieve the on-off control between the second communication cavity and the water outlet channel.

[0028] The other side of the installation cavity is sealed by a plug. In this way, the plug can be opened when installing the main valve, and the plug can be installed after the installation is completed, so the overall installation is more convenient.

[0029] Part of the first communication cavity and the second communication cavity is set on the pump cover, so that it is convenient to open through the first pressure relief hole and the second pressure relief hole, and the processing is more convenient. Description of the Drawings

[0030] Figure 1 It is a schematic structural diagram of a plunger pump with a high-pressure-holding overflow valve.

[0031] Figure 2 It is a sectional view of a plunger pump with a high-pressure-holding overflow valve from a perspective in the normal working state.

[0032] Figure 3 It is a sectional view of a plunger pump with a high-pressure-holding overflow valve from a perspective when in the state of gun closing and backwashing.

[0033] Figure 4 It is a sectional view of a plunger pump with a high-pressure-holding overflow valve from a perspective when in the state of gun closing and holding for shutdown.

[0034] Figure 5 It is a sectional view of a plunger pump with a high-pressure-holding overflow valve from another perspective.

[0035] Figure 6 It is a schematic structural diagram of the pump cover in a plunger pump with a high-pressure-holding overflow valve.

[0036] Figure 7 It is a schematic structural diagram of a push rod seat in a plunger pump with a high-pressure holding overflow valve.

[0037] Figure 8 It is a schematic structural diagram of a spool in a plunger pump with a high-pressure holding overflow valve.

[0038] Figure 9 It is a front view schematic diagram of a pump body in a plunger pump with a high-pressure holding overflow valve.

[0039] Figure 10 It is a rear view schematic diagram of a pump body in a plunger pump with a high-pressure holding overflow valve.

[0040] As shown in the figure: 1. Pump cover; 2. Pump body; 3. Water inlet channel; 4. Water outlet channel; 5. Overflow channel; 6. Main valve; 7. Overflow valve; 8. Low-pressure check valve; 9. High-pressure check valve; 10. Plunger cavity; 11. First communication cavity; 12. Second communication cavity; 13. First pressure relief hole; 14. Second pressure relief hole; 15. Valve cover; 16. Spool; 17. Sealing ring; 18. Thumb rod; 19. Steel ball; 20. Push rod; 21. Spring; 22. Push rod seat; 23. Micro switch; 24. Thumb rod cavity; 25. Push rod cavity; 26. Communication hole; 27. Groove; 28. Block; 29. First annular groove; 30. Second annular groove; 31. Third annular groove; 32. Sealing member; 33. First connection hole; 34. Second connection hole; 35. Installation cavity; 36. Plug; 37. First circular closed loop; 38. Second circular closed loop; 39. Triangular closed loop. Specific embodiments

[0041] The following details the embodiments of the present invention. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0042] Embodiment 1:

[0043] A plunger pump with a high-pressure holding overflow valve, as Figure 1 shown, includes a pump cover 1 and a pump body 2, where:

[0044] The pump cover 1, as Figure 6As shown, it is an integral unit with an installation cavity 35 provided in the middle. The installation cavity 35 penetrates through the pump cover 1, that is, both the front and rear ends of the installation cavity 35 are open. On the outer part of the pump cover 1, there are respectively a water inlet channel 3, a water outlet channel 4, and an overflow channel 5. The water outlet channel 4 and the overflow channel 5 are both communicated with the installation cavity 35. One side of the pump cover 1 is for installing the pump body 2. On this side of the pump cover 1, there are a first circular closed loop 37, a second circular closed loop 38, and a triangular closed loop 39. The first circular closed loop 37 is located on the outer circumference on one side of the installation cavity 35. The second circular closed loop 38 is located outside the first circular closed loop 37. The triangular closed loop 39 is located outside the second circular closed loop 38. A first communication cavity 11 is formed between the triangular closed loop 39 and the second circular closed loop 38. The water inlet channel 3 is communicated with the first communication cavity 11. A second pressure relief hole 14 is opened on the cavity wall of the first communication cavity 11. The second pressure relief hole 14 is communicated to the front part of the overflow channel 5, specifically to the push rod cavity 24 of the overflow valve 7 installed in the overflow channel 5. A second communication cavity 12 is formed between the second circular closed loop 38 and the first circular closed loop 37, and the second communication cavity 12 is communicated with one side of the installation cavity 35. A first pressure relief hole 13 is opened on the wall of the second communication cavity 12. The first pressure relief hole 13 is communicated to the rear part of the overflow channel 5, specifically to the push rod cavity 25 of the overflow valve 7 installed in the overflow channel 5;

[0045] A main valve 6 is installed in the installation cavity 35. As Figure 5 shown, the main valve 6 includes a main valve seat, a main valve spool, a main valve spring, and a plug 36. The plug 36 is installed on the other side of the installation cavity 35 to play a sealing role, and the plug 36 can be taken out during installation and reinstalled after the main valve 6 is installed. The main valve seat is fixed in the installation cavity 35. The main valve spool is arranged in the main valve seat. One end of the main valve spring abuts against the main valve spool, and the other end abuts against the plug 36. And a guide hole for one end of the main valve spool to extend into is also provided on the plug 36. The other end of the main valve spool is used to seal the other side of the installation cavity 35. Only when the water pressure in the second communication cavity 12 is greater than the thrust of the main valve spring, the main valve 6 will be opened. The structure and installation form of the main valve 6 itself are similar to those of the prior art plunger pump, so the installation structure of the main valve 6 is not described in detail in this application;

[0046] The pump body 2, as Figure 9 connected to Figure 10 shown, is connected to the pump cover 1. Figure 10 The upper end surface of the pump body 2 is connected to the pump cover 1. The pump body 2 is also provided with a first communication cavity 11 and a second communication cavity 12 that match the pump cover 1. And a low-pressure one-way valve 8 is provided on the first communication cavity 11 of the pump body 2, a high-pressure one-way valve 9 is provided on the second communication cavity 12 of the pump body 2, and a plunger cavity 10 is provided between the low-pressure one-way valve 8 and the high-pressure one-way valve 9. A plunger is arranged in the plunger cavity 10;

[0047] That is, the overall connected structure of this application includes, in sequence and connection: an inlet passage 3, a first connection cavity 11, a low-pressure check valve 8, a plunger cavity 10, a high-pressure check valve 9, a second connection cavity 12, an installation cavity 35, an outlet passage 4, and an overflow passage 5; and on this basis, the overflow passage 5 is further connected to the first connection cavity 11 through a first pressure relief hole 13, and the overflow passage 5 is also connected to the second connection cavity 12 through a second pressure relief hole 14;

[0048] An overflow valve 7 is also installed in the overflow passage 5, as Figure 2 shown. The overflow valve 7 includes a valve cover 15, a valve core 16, a sealing ring 17, a push rod 18, a steel ball 19, a push rod 20, a spring 21, a push rod seat 22, a retaining ring, a nut, a slider, and a micro switch 23, where:

[0049] The push rod seat 22, as Figure 7 shown, is arranged in the overflow passage 5. The front end of the push rod seat 22 is installed with a valve cover 15, which abuts against the inside of the pump cover 1 through the valve cover 15. The rear end of the push rod seat 22 abuts against the nut, and the nut is threadedly connected to the rear part of the overflow passage 5; the interior of the push rod seat 22 is divided into a push rod cavity 24 and a push rod chamber 25, and the push rod cavity 24 and the push rod chamber 25 are connected through a communication hole 26;

[0050] The sealing ring 17 is arranged between the valve cover 15 and the push rod seat 22;

[0051] A first connection hole 33 is arranged on the outer wall of the push rod seat 22 corresponding to the push rod cavity 24, and a second connection hole 34 is arranged on the outer wall of the push rod seat 22 corresponding to the push rod chamber 25. The first connection hole 33 is communicated with the second pressure relief hole 14, and the second connection hole 34 is communicated with the first pressure relief hole 13;

[0052] The push rod 18 is arranged in the push rod cavity 24, and a valve core 16 is sleeved on the front end of the push rod 18. A groove 27 is arranged on the outer circumference of the front part of the valve core 16, as Figure 8 shown. In this embodiment, there are two grooves 27. The rear end of the push rod 18 extends into the communication hole 26 and is guided by the communication hole 26. However, there is still a certain gap between the rear end of the push rod 18 and the communication hole 26, so water can flow through the gap;

[0053] The push rod 20 is arranged in the push rod chamber 25. The diameter of the front part of the push rod 20 matches that of the push rod chamber 25. The steel ball 19 is fixed at the front end of the push rod 20, and the steel ball 19 can seal the communication hole 26. A retaining ring is fixed in the nut. The rear end of the push rod 20 passes through the retaining ring. The spring 21 is sleeved on the push rod 20. One end of the spring 21 abuts against the retaining ring, and the other end of the spring 21 abuts against the push rod 20. In this way, the spring 21 can give the push rod 20 a forward thrust;

[0054] A switch box is installed at the rear of the nut, and the micro switch 23 and the slider are installed in the switch box. The rear end of the push rod 20 is against the slider, and the contact part between the slider and the rear end of the push rod 20 is an inclined surface, so that the vertical movement of the push block can drive the slider to move horizontally, thereby controlling the on and off of the micro switch 23;

[0055] The overall working principle of this embodiment is:

[0056] When in normal working condition, such as Figure 2 As shown, that is, the state of firing and discharging water, at this time, the water outlet channel 4 is open, the micro switch 23 is energized, and because the water pressure in the second communicating chamber 12 is high, the main valve 6 is also open, and the water flows in from the water inlet channel 3, passes through the first communicating chamber 11, the low-pressure one-way valve 8, the plunger pressurization of the plunger chamber 10, the high-pressure one-way valve 9, the main valve 6, and finally flows out from the water outlet channel 4;

[0057] When in the state of gun closing recoil, such as Figure 3 As shown, that is, the initial period of time when the water gun is closed, at this time the water outlet channel 4 is closed, and the water flow pressure in the water outlet channel 4 is relatively large, so that the main valve 6 is closed, and then because the water pressure in the water outlet channel 4 is relatively large, the valve core 16 of the overflow valve 7 will be pushed open, and the valve core 16, the push rod 18, the steel ball 19 and the push rod 20 will be pushed back together. At this time, because the push rod 20 is also pushed back, the micro switch 23 is in a triggered state, and the water gun is in a power-off state. At the same time, because the push rod 18 pushes the steel ball 19 away from the sealing position of the connecting hole 26, the connecting hole 26 is connected at this time, so that the push rod cavity 24 is connected to the push rod cavity 25, and the seal is The seal ring 17 matches the position of the groove 27 on the valve core 16, so that the water outlet channel 4 is connected to the push rod chamber 24. At this time, the water flow in the water outlet channel 4 will first flow into the push rod chamber 24, and then flow into the push rod chamber 25 through the connecting hole 26, and then flow back to the water inlet channel 3 through the second connecting hole 34, the first pressure relief hole 13 and the first connecting chamber 11, so as to achieve the pressure relief of the water outlet channel 4, and the water flow in the second connecting chamber 12 will flow into the push rod chamber 24 through the second pressure relief hole 14 and the first connecting hole 33, and then this part of the water flow will also flow back to the water inlet channel 3 together with the water flow in the water outlet channel 4, so as to achieve the pressure relief of the second connecting chamber 12;

[0058] When the gun is closed and the machine is stopped, Figure 4As shown, after the gun-closing recoil state lasts for a period of time, the water outlet channel 4 and the second connecting chamber 12 are depressurized for a period of time, and the pressure has been reduced a lot. That is, the water pressure in the water outlet channel 4 can no longer completely push open the valve core 16. The valve core 16, the push rod 18, the steel ball 19, and the push rod 20 will move forward under the action of the spring 21 until the groove 27 of the valve core 16 is staggered with the sealing ring 17. At this time, the sealing ring 17 is sealed with the valve core 16, that is, the water outlet channel 4 is separated from the push rod chamber 24. However, because the valve core 16, the push rod 18, the steel ball 19, and the push rod 20 are not completely pushed into place by the spring 21, the steel ball 19 does not support the connecting hole 26 at this time, the push rod chamber 24 and the push rod chamber 25 are still connected, and the microswitch 23 is still pushed open by the slider in the triggered state, and the water gun is still in the power-off state. At this time, the water pressure of the second connecting chamber 12 plus the thrust of the spring 21 is balanced with the water pressure in the water outlet channel 4.

[0059] Embodiment 2:

[0060] The difference from the first embodiment is that in the second embodiment, a stop block 28 is provided on the cavity wall of the push rod cavity 24 close to the connecting hole 26. This embodiment specifically has two blocks. In this way, when the gun is in the recoil state, the valve core 16 is pushed by the water flow and is against the stop block 28. In this way, the gap between the valve core 16 and the connecting hole 26 is not large, and the water flow in the water outlet channel 4 can be quickly depressurized.

[0061] Embodiment three:

[0062] The difference from the first embodiment is that in the third embodiment, three annular grooves are sequentially arranged on the outer wall of the push rod seat 22 corresponding to the push rod cavity 24, namely the first annular groove 29, the second annular groove 30 and the third annular groove 31, wherein a first connecting hole 33 is arranged at the bottom of the second annular groove 30, and sealing members 32 are arranged in both the first annular groove 29 and the third annular groove 31, and one side wall of the second annular groove 30 is inclined, so that the connecting space between the first connecting hole 33 and the second pressure relief hole 14 will be sealed by two sealing members 32, and this connecting space will also be relatively large.

[0063] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

[0064] For those skilled in the art, after reading the above description, various changes and modifications will undoubtedly be obvious. Therefore, the appended claims should be regarded as covering all changes and modifications that fall within the true intent and scope of this utility model. Any and all equivalent ranges and contents within the scope of the claims should be considered to still fall within the intent and scope of this utility model.

Claims

1. A plunger pump with a high-pressure relief valve, comprising a pump cover (1) and a pump body (2), wherein the pump cover (1) is provided with a water inlet channel (3), a water outlet channel (4), an overflow channel (5) and a main valve (6), wherein the water outlet channel (4) is connected to the overflow channel (5), and the overflow channel (5) is provided with a relief valve (7), wherein the pump body (2) is provided with a low-pressure check valve (8), a high-pressure check valve (9) and a plunger cavity (10 ), a plunger cavity (10) is arranged between a low-pressure one-way valve (8) and a high-pressure one-way valve (9), a plunger is arranged in the plunger cavity (10), a first connecting cavity (11) is arranged between the low-pressure one-way valve (8) and the water inlet channel (3), a second connecting cavity (12) is arranged between the high-pressure one-way valve (9) and the main valve (6), and the overflow channel (5) is connected to the first connecting cavity (11) through a first pressure relief hole (13), characterized in that: The overflow channel (5) is connected to the second communication chamber (12) via the second pressure relief hole (14). When in a normal working state, the outlet of the water outlet channel (4) is opened, the main valve (6) is opened, and the overflow valve (7) is closed, and the water in the second connecting chamber (12) flows out from the water outlet channel (4); When in the gun-off recoil state, the outlet of the water outlet channel (4) is closed, the main valve (6) is closed, the overflow valve (7) is fully opened, the water flow in the second connecting chamber (12) is guided to the overflow channel (5) through the second pressure relief hole (14), and the water flow in the water outlet channel (4) is guided to the first connecting chamber (11) and then to the water inlet channel (3) through the overflow channel (5) and the first pressure relief hole (13); When in the gun-off protection shutdown state, the outlet of the water outlet channel (4) is closed, the main valve (6) is closed, and the overflow valve (7) is partially opened. At this time, the water outlet channel (4) is isolated from the first pressure relief hole (13) and the second pressure relief hole (14).

2. A plunger pump with a high pressure relief valve according to claim 1, characterized in that: The overflow valve (7) comprises a valve cover (15), a valve core (16), a sealing ring (17), a push rod (18), a steel ball (19), a push rod (20), a spring (21), a push rod seat (22) and a micro switch (23); the push rod seat (22) is arranged in the overflow channel (5), and a push rod cavity (24) and a push rod cavity (25) are arranged in the push rod seat (22); the push rod cavity (24) and the push rod cavity (25) are connected through a connecting hole (26); the first pressure relief hole (13) is connected to the push rod cavity (25), and the second pressure relief hole (14) is connected to the push rod cavity (24); the valve cover (15) is provided with The push rod (20) is arranged at the front end of the push rod seat (22), a sealing ring (17) is arranged between the valve cover (15) and the push rod seat (22), the push rod (18) is arranged in the push rod cavity (24), the valve core (16) is sleeved on the front end of the push rod (18), and a groove (27) is arranged at the front end of the valve core (16), the sealing ring (17) and the valve core (16) are matched and sealed, the push rod (20) is arranged in the push rod cavity (25), the steel ball (19) is arranged at the front end of the push rod (20), the micro switch (23) is located at the rear side of the push rod (20), and the spring (21) is sleeved on the push rod (20) and applies thrust to the push rod (20). When in normal working state, the outlet of the water outlet channel (4) is opened, the main valve (6) is opened, and the water pressure received by the valve core (16) is less than the thrust applied by the spring (21). At this time, the micro switch (23) is in an untriggered state, and the connecting hole (26) is sealed by the steel ball (19), so that the push rod cavity (24) is isolated from the push rod cavity (25), and the sealing ring (17) and the valve core (16) are matched and sealed, so that the water outlet channel (4) is isolated from the push rod cavity (24); When the gun is in the recoil state, the outlet of the water outlet channel (4) is closed, the main valve (6) is closed, and the water pressure on the valve core (16) is greater than the thrust applied by the spring (21). At this time, the valve core (16), the push rod (18), the steel ball (19) and the push rod (20) are pushed back together. At this time, the micro switch (23) is in the triggered state, the connecting hole (26) is connected, so that the push rod cavity (24) and the push rod cavity (25) are connected, and the sealing ring (17) matches the position of the groove (27) on the valve core (16), so that the water outlet channel (4) and the push rod cavity (24) are connected; When the gun is in the shutdown state, the outlet of the water outlet channel (4) is closed, the main valve (6) is closed, the water pressure on the valve core (16) is less than the thrust applied by the spring (21), the valve core (16), the push rod (18), the steel ball (19) and the push rod (20) are pushed forward together until the sealing ring (17) and the valve core (16) cooperate to seal, so that the water outlet channel (4) and the push rod chamber (24) are isolated. At this time, the micro switch (23) is still in the triggered state, the connecting hole (26) is still connected, so that the push rod chamber (24) and the push rod chamber (25) are connected.

3. A plunger pump with a high pressure relief valve according to claim 2, characterized in that: The push rod cavity (24) is provided with a stop block (28) near the communicating hole (26) for the valve core (16) to stop against. When in the gun closing recoil state, the valve core (16) abuts against the stop block (28).

4. A plunger pump with a high pressure relief valve according to claim 2, characterized in that: Three annular grooves are sequentially arranged on the outer side of the push rod seat (22) corresponding to the push rod cavity (24), namely a first annular groove (29), a second annular groove (30) and a third annular groove (31); a sealing member (32) is arranged on the first annular groove (29) and the third annular groove (31); a first connecting hole (33) is arranged on the bottom of the second annular groove (30); and the first connecting hole (33) is connected to the second pressure relief hole (14).

5. A plunger pump with a high pressure relief valve according to claim 4, characterized in that: One side groove wall of the second annular groove (30) is arranged inclined.

6. A plunger pump with a high pressure relief valve according to claim 2, characterized in that: A second connecting hole (34) is provided on the outside of the push rod seat (22) corresponding to the push rod cavity (25), and the second connecting hole (34) is close to the communicating hole (26), and the second connecting hole (34) is communicated with the first pressure relief hole (13).

7. A plunger pump with a high pressure relief valve according to claim 1, characterized in that: The pump cover (1) is provided with a mounting cavity (35), the main valve (6) is mounted in the mounting cavity (35), and the water outlet channel (4) and the second connecting cavity (12) are both connected to the mounting cavity (35); when the main valve (6) is opened, the second connecting cavity (12) is connected to the water outlet channel (4); when the main valve (6) is closed, the second connecting cavity (12) is isolated from the water outlet channel (4).

8. A plunger pump with a high pressure relief valve according to claim 7, characterized in that: The main valve (6) comprises a plug (36), one side of the installation cavity (35) is connected to the second communication cavity (12), and the other side of the installation cavity (35) is sealed by the plug (36).

9. A plunger pump with a high pressure relief valve according to claim 8, characterized in that: The pump cover (1) is provided with a first circular closed ring (37), a second circular closed ring (38) and a triangular closed ring (39) on one side close to the pump body (2); the first circular closed ring (37) is arranged on the outer ring of one side of the installation cavity (35); the second circular closed ring (38) is sleeved outside the first circular closed ring (37); the triangular closed ring (39) is sleeved outside the second circular closed ring (38); the second circular closed ring (38) and the triangular closed ring (39) are located between the first connecting cavity (11); the first pressure relief hole (13) is located between the second circular closed ring (38) and the triangular closed ring (39); the first circular closed ring (37) and the second circular closed ring (38) are located between the second connecting cavity (12); and the second pressure relief hole (14) is located between the first circular closed ring (37) and the second circular closed ring (38).

Images