Unloading valve

Abstract

The present invention provides a unloading valve, which comprises: a main valve including a main valve body, a unloading valve core and a loading valve core. The main valve body has a unloading valve cavity, a loading valve cavity and a main valve liquid inlet. One end of the unloading valve cavity has a unloading valve port communicating with the main valve liquid inlet. The unloading valve core can open or block the unloading valve port. One end of the loading valve cavity has a loading valve port communicating with the main valve liquid inlet. The loading valve core can open or block the loading valve port; an electromagnetic pilot valve includes a pilot valve body and a pilot valve core. The pilot valve body has a first pilot port, a second pilot port and a third pilot port. When the pilot valve core is in the loading position, the second pilot port communicates with the first pilot port. When the pilot valve core is switched from the loading position to the unloading position, the second pilot port communicates with the third pilot port. Through the technical solution provided by the present application, the problem that the flow rate of the electromagnetic pilot valve in the related art is relatively large, making the electromagnetic pilot valve vulnerable to contamination can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of unloading valves, and more particularly, to an unloading valve. Background Art

[0002] The emulsion pump station is the power source of the hydraulic support, providing hydraulic power for its initial support force, pushing, pulling the support and other actions. The curve of the liquid flow rate actually required by the hydraulic support on the time axis is a rectangular wave curve. In order to solve the matching of the actual required flow rate and the output flow rate of the emulsion pump station, at present, the emulsion pump station uses an unloading valve to adjust and match the flow rate output from the pump station to the working face. Among them, the unloading valve is an important component for controlling the loading and unloading of the emulsion pump station, and whether its function is normal directly affects the normal operation of the working face. The unloading valve and its spare parts have always been one of the most core components of the pump station equipment.

[0003] In the related art, when the unloading valve unloads, it needs to use an electromagnetic pilot valve and a mechanical pilot valve to control the unloading together, and the unloading valve port is opened by moving the unloading valve core upward.

[0004] However, in the related art, in the way of combining the electromagnetic pilot valve and the mechanical pilot valve, the flow rate of the electromagnetic pilot valve is relatively large, making the electromagnetic pilot valve vulnerable to contamination. Summary of the Invention

[0005] The present invention provides an unloading valve to solve the problem in the related art that the flow rate of the electromagnetic pilot valve is relatively large, making the electromagnetic pilot valve vulnerable to contamination.

[0006] The present invention provides a pressure relief valve, which includes: a main valve, comprising a main valve body, a pressure relief valve core and a loading valve core. The main valve body has a pressure relief valve cavity, a loading valve cavity and a main valve inlet located between the pressure relief valve cavity and the loading valve cavity. One end of the pressure relief valve cavity has a pressure relief valve port communicating with the main valve inlet. The pressure relief valve core is movably arranged in the pressure relief valve cavity to open or block the pressure relief valve port. One end of the loading valve cavity has a loading valve port communicating with the main valve inlet. The loading valve core is movably arranged in the loading valve cavity to open or block the loading valve port. The main valve body also has a pressure relief outlet communicating with the pressure relief valve cavity and a loading outlet communicating with the loading valve cavity; an electromagnetic pilot valve, comprising a pilot valve body and a pilot valve core. The pilot valve body has a pilot valve cavity and a first pilot port, a second pilot port and a third pilot port communicating with the pilot valve cavity. The pilot valve core has a loading position and a pressure relief position to make the second pilot port communicate with the first pilot port or make the second pilot port communicate with the third pilot port; wherein, one end of the main valve body far from the pressure relief valve port has a back pressure pilot cavity communicating with the pressure relief valve cavity. The cross-sectional dimension of the back pressure pilot cavity is larger than that of the pressure relief valve port. The main valve body has a pilot channel. One end of the pilot channel communicates with the pressure relief valve port, and the other end of the pilot channel communicates with the back pressure pilot cavity. The main valve inlet or the pressure relief outlet is connected to the first pilot port, the second pilot port is connected to the back pressure pilot cavity, and the third pilot port is connected to the outside. When the pilot valve core is in the loading position, the second pilot port communicates with the first pilot port. When the pilot valve core is switched from the loading position to the pressure relief position, the second pilot port communicates with the third pilot port.

[0007] Further, the main valve further includes a pressure relief valve sleeve arranged in the pressure relief valve cavity. The pressure relief valve port is arranged at the lower end of the pressure relief valve sleeve. The pressure relief valve core movably penetrates through the pressure relief valve sleeve. A pressure relief diversion hole communicating with the pressure relief outlet is penetrated through the side wall of the pressure relief valve sleeve.

[0008] Further, the pressure relief valve sleeve includes a pressure relief guide sleeve and a pressure relief diversion sleeve connected to the lower end of the pressure relief guide sleeve. The outer side wall of the pressure relief valve core is in clearance fit with the inner side wall of the pressure relief guide sleeve. The pressure relief valve port is arranged at the lower end of the pressure relief diversion sleeve. The pressure relief diversion hole is arranged on the side wall of the pressure relief diversion sleeve.

[0009] Further, an annular positioning groove extending along its circumferential direction is arranged at the lower end of the pressure relief guide sleeve. An annular positioning boss is arranged at the upper end of the pressure relief diversion sleeve. The annular positioning boss is embedded in the annular positioning groove; and / or, the main valve further includes a positioning pin. A first positioning hole is arranged at the upper end of the pressure relief guide sleeve. The main valve body has a second positioning hole opposite to the first positioning hole. The positioning pin is inserted into the first positioning hole and the second positioning hole.

[0010] Further, a plurality of unloading diversion holes are provided on the side wall of the unloading valve sleeve, the plurality of unloading diversion holes are arranged at intervals along the circumferential direction of the unloading valve sleeve, and at least one of the plurality of unloading diversion holes is disposed opposite to the unloading liquid outlet; and / or, an annular diversion groove extending along the circumferential direction is provided on the outer side wall of the unloading valve core, and the annular diversion groove is disposed opposite to the unloading diversion hole.

[0011] Further, the main valve further includes a loading valve seat disposed in the loading valve cavity, the loading valve core is movably inserted through the loading valve seat, the loading valve port is provided at the upper end of the loading valve seat, and a loading diversion hole penetrating through is provided on the side wall of the loading valve seat, and the loading diversion hole is disposed opposite to the loading liquid outlet.

[0012] Further, the loading diversion hole is a long strip-shaped hole extending along the circumferential direction of the loading valve seat; and / or, a plurality of loading diversion holes are provided on the side wall of the loading valve seat, and the plurality of loading diversion holes are arranged at intervals along the circumferential direction of the loading valve seat.

[0013] Further, the main valve further includes a loading guide sleeve disposed in the loading valve seat, the loading valve core includes a guide rod and a sealing plate disposed at the upper end of the guide rod, the sealing plate can open or block the loading valve port, the loading guide sleeve has a guide hole, the guide rod is inserted in the guide hole, and the outer side wall of the guide rod is in clearance fit with the hole wall of the guide hole; the main valve further includes a return spring, the return spring is sleeved on the guide rod, the upper end of the return spring abuts against the lower surface of the sealing plate, and the lower end of the return spring abuts against the upper surface of the loading guide sleeve.

[0014] Further, the main valve body includes a main valve body, a first valve cover and a second valve cover, the unloading valve cavity is provided at the upper end of the main valve body, the loading valve cavity is provided at the lower end of the main valve body, the main valve liquid inlet is provided on the side wall of the main valve body, the back pressure pilot cavity is provided on the lower end surface of the first valve cover, the first valve cover covers the upper end of the main valve body, and the second valve cover covers the lower end of the main valve body.

[0015] Further, the unloading valve further includes a pressure sensor and an electric control component, the pressure sensor is disposed at the loading liquid outlet, and the electric control component is electrically connected to the pressure sensor and the electromagnetic pilot valve respectively; and / or, when the electromagnetic pilot valve is energized, the pilot valve core is located at the loading position, and when the electromagnetic pilot valve is de-energized, the pilot valve core is located at the unloading position.

[0016] Applying the technical solution of the present invention, the unloading valve includes a main valve and an electromagnetic pilot valve. The main valve body in the main valve has a main valve liquid inlet, and the liquid enters the main valve body through the main valve liquid inlet. An unloading valve core and a loading valve core are also arranged in the main valve, which can perform the working process of loading or unloading the liquid entering through the main valve liquid inlet. Among them, the unloading valve core can move in the unloading valve cavity so that the unloading valve core can open or block the unloading valve port, and the loading valve core can move in the loading valve cavity so that the loading valve core can open or block the loading valve port, thereby enabling the main valve to control the working process of unloading or loading the liquid in the main valve body. And an electromagnetic pilot valve is provided to facilitate the automatic control of the loading or unloading working process of the main valve. The electromagnetic pilot valve has a pilot valve body, and the pilot valve core in the pilot valve body is arranged in the pilot valve cavity, enabling the pilot valve core to switch between the loading position and the unloading position. When loading the liquid, the electromagnetic pilot valve controls the pilot valve core to be in the loading position. The liquid enters the main valve body through the main valve liquid inlet. The main valve body has a pilot channel, one end of the pilot channel is communicated with the main valve liquid inlet or the unloading liquid outlet, and the other end of the pilot channel is communicated with the back-pressure pilot cavity, so that part of the liquid enters the pilot channel and flows into the pilot valve body through the first pilot port. When the pilot valve core is in the loading position, the first pilot port is communicated with the second pilot port, and part of the liquid flows out from the second pilot port and enters the back-pressure pilot cavity. By using the pilot channel to direct part of the liquid to flow into the back-pressure pilot cavity, the flow rate of the electromagnetic pilot valve can be greatly reduced, the tendency of the electromagnetic pilot valve to be contaminated can be reduced, the trouble-free operation time of the precision pilot can be increased, and since the cross-sectional area of the back-pressure pilot cavity is larger than the cross-sectional area of the unloading valve port, the liquid pressure in the back-pressure pilot cavity is greater than the liquid pressure at the unloading valve port, and the unloading valve core is in the blocked position without moving. At this time, the loading valve core moves to the open position, enabling the liquid to enter the loading valve core through the loading valve port, realizing the loading working process, and discharging through the loading liquid outlet. When the liquid is loaded to a certain pressure, it is necessary to unload the liquid. The electromagnetic pilot valve controls the pilot valve core to switch from the loading position to the unloading position. At this time, the second pilot port is communicated with the third pilot port, enabling the liquid in the back-pressure pilot cavity to flow into the third pilot port through the second pilot port, discharging the liquid in the back-pressure pilot cavity. And after all the liquid in the back-pressure pilot cavity is discharged, since the first pilot port is not conducting and no other liquid flows into the electromagnetic pilot valve, the tendency of the electromagnetic pilot valve to be contaminated can be reduced while ensuring the normal operation of the unloading valve. At this time, the liquid pressure at the unloading valve port is greater than the liquid pressure in the back-pressure pilot cavity. At this time, the unloading valve core moves to open the unloading valve port, and the liquid enters the unloading valve core through the unloading valve port for unloading, and the liquid is discharged through the unloading liquid outlet, and the loading valve core is in the blocked position, avoiding the simultaneous operation of the loading valve core and the unloading valve core, and improving the sustainability of the unloading valve working process.With the above structure, by setting an electromagnetic pilot valve to control the main valve for unloading or loading, it is convenient to achieve automatic control. Moreover, the unloading valve is redesigned to ensure the reliability of the unloading valve core. By setting a pilot channel, the flow rate of the electromagnetic pilot valve can be greatly reduced, reducing the tendency of the electromagnetic pilot valve to be contaminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 shows a schematic structural view of an unloading valve in the prior art;

[0019] Figure 2 shows a schematic principle view of an unloading valve in the prior art;

[0020] Figure 3 shows a cross-sectional view of an unloading valve in the prior art;

[0021] Figure 4 shows a front view of an unloading valve provided by an embodiment of the present invention;

[0022] Figure 5 shows Figure 4 a cross-sectional view taken along line A-A in

[0023] Figure 6 shows Figure 5 a partial enlarged view at B in

[0024] Figure 7 shows a side view of an unloading valve provided by an embodiment of the present invention;

[0025] Figure 8 shows Figure 7 a cross-sectional view taken along line C-C in

[0026] Figure 9 shows a schematic principle view of an unloading valve provided by an embodiment of the present invention;

[0027] Figure 10 shows a schematic structural view of a loading valve core of an unloading valve provided by an embodiment of the present invention;

[0028] Figure 11 shows Figure 10 a cross-sectional view taken along line D-D in

[0029] Figure 12 shows a schematic structural view of an unloading diversion sleeve of an unloading valve provided by an embodiment of the present invention;

[0030] Figure 13The structural schematic diagram of the unloading guide sleeve of the unloading valve provided by the embodiment of the present invention is shown.

[0031] Among them, the above-mentioned drawings include the following reference numerals:

[0032] 1', mechanical pilot valve; 2', push rod; 3', elastic member; 11', main valve body; 12', unloading valve core; 13', loading valve core; 18', return spring; 20', electromagnetic pilot valve; 61', pilot filter; 62', unloading pipeline; 63', loading pipeline;

[0033] 10, main valve; 11, main valve body; 111, unloading valve cavity; 1111, unloading valve port; 112, loading valve cavity; 1121, loading valve port; 113, main valve inlet; 114, unloading outlet; 115, loading outlet; 116, back pressure pilot cavity; 117, pilot channel; 118, second positioning hole; 12, unloading valve core; 121, annular diversion groove; 13, loading valve core; 131, guide rod; 132, sealing plate; 14, unloading valve sleeve; 141, unloading diversion hole; 142, unloading guide sleeve; 1421, annular positioning groove; 1422, first positioning hole; 143, unloading diversion sleeve; 1431, annular positioning boss; 15, positioning pin; 16, loading valve seat; 161, loading diversion hole; 1611, long strip hole; 17, loading guide sleeve; 171, guide hole; 18, return spring;

[0034] 20, electromagnetic pilot valve; 21, pilot valve body; 211, pilot valve cavity; 212, first pilot port; 213, second pilot port; 214, third pilot port;

[0035] 31, main valve body; 32, first valve cover; 33, second valve cover;

[0036] 40, pressure sensor; 50, electrical control component;

[0037] 61, pilot filter; 62, unloading pipeline; 63, loading pipeline. Specific embodiments

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0039] Such as Figures 4 to 13As shown in the figure, an embodiment of the present invention provides a unloading valve. The unloading valve includes a main valve 10 and an electromagnetic pilot valve 20. The main valve 10 includes a main valve body 11, a unloading valve core 12 and a loading valve core 13. The main valve body 11 has a unloading valve cavity 111, a loading valve cavity 112 and a main valve liquid inlet 113 located between the unloading valve cavity 111 and the loading valve cavity 112. One end of the unloading valve cavity 111 has a unloading valve port 1111 communicating with the main valve liquid inlet 113. The unloading valve core 12 is movably arranged in the unloading valve cavity 111 to open or block the unloading valve port 1111. One end of the loading valve cavity 112 has a loading valve port 1121 communicating with the main valve liquid inlet 113. The loading valve core 13 is movably arranged in the loading valve cavity 112 to open or block the loading valve port 1121. The main valve body 11 also has a unloading liquid outlet 114 communicating with the unloading valve cavity 111 and a loading liquid outlet 115 communicating with the loading valve cavity 112. The electromagnetic pilot valve 20 includes a pilot valve body 21 and a pilot valve core. The pilot valve body 21 has a pilot valve cavity 211 and a first pilot port 212, a second pilot port 213 and a third pilot port 214 communicating with the pilot valve cavity 211. The pilot valve core has a loading position and a unloading position to make the second pilot port 213 communicate with the first pilot port 212, or make the second pilot port 213 communicate with the third pilot port 214. Wherein, one end of the main valve body 11 far from the unloading valve port 1111 has a back pressure pilot cavity 116 communicating with the unloading valve cavity 111. The cross-sectional dimension of the back pressure pilot cavity 116 is larger than that of the unloading valve port 1111. The main valve body 11 has a pilot channel 117. One end of the pilot channel 117 communicates with the unloading valve port 1111, and the other end of the pilot channel 117 communicates with the back pressure pilot cavity 116. The main valve liquid inlet 113 or the unloading liquid outlet 114 communicates with the first pilot port 212. The second pilot port 213 communicates with the back pressure pilot cavity 116. The third pilot port 214 communicates with the outside. When the pilot valve core is in the loading position, the second pilot port 213 communicates with the first pilot port 212. When the pilot valve core is switched from the loading position to the unloading position, the second pilot port 213 communicates with the third pilot port 214.

[0040] Apply the unloading valve provided in this embodiment. The unloading valve includes a main valve 10 and an electromagnetic pilot valve 20. The main valve body 11 in the main valve 10 has a main valve liquid inlet 113, and liquid enters the main valve body 11 through the main valve liquid inlet 113. An unloading valve core 12 and a loading valve core 13 are also arranged in the main valve 10, which can perform the working process of loading or unloading the liquid entering through the main valve liquid inlet 113. Among them, the unloading valve core 12 can move in the unloading valve cavity 111 so that the unloading valve core 12 can open or block the unloading valve port 1111, and the loading valve core 13 can move in the loading valve cavity 112 so that the loading valve core 13 can open or block the loading valve port 1121, thereby enabling the main valve 10 to control the working process of unloading or loading the liquid in the main valve body 11. And the electromagnetic pilot valve 20 is provided to facilitate the automatic control of the loading or unloading of the main valve 10. The electromagnetic pilot valve 20 has a pilot valve body 21, and the pilot valve core in the pilot valve body 21 is arranged in the pilot valve cavity 211, so that the pilot valve core can be switched between the loading position and the unloading position. When loading the liquid, the electromagnetic pilot valve 20 controls the pilot valve core to be in the loading position. The liquid enters the main valve body 11 through the main valve liquid inlet 113. The main valve body 11 has a pilot channel 117. One end of the pilot channel 117 is communicated with the main valve liquid inlet 113 or the unloading liquid outlet 114, and the other end of the pilot channel 117 is communicated with the back-pressure pilot cavity 116, so that part of the liquid enters the pilot channel 117 and flows into the pilot valve body 21 through the first pilot port 212. When the pilot valve core is in the loading position, the first pilot port 212 is communicated with the second pilot port 213, and part of the liquid flows out from the second pilot port 213 and enters the back-pressure pilot cavity 116. By using the pilot channel 117 to direct part of the liquid to flow into the back-pressure pilot cavity 116, the over-flow rate of the electromagnetic pilot valve 20 can be greatly reduced, the pollution tendency of the electromagnetic pilot valve 20 can be reduced, the trouble-free operation time of the precision pilot can be increased, and since the cross-sectional area of the back-pressure pilot cavity 116 is larger than the cross-sectional area of the unloading valve port 1111, the liquid pressure in the back-pressure pilot cavity 116 is greater than the liquid pressure at the unloading valve port 1111, and the unloading valve core 12 is in the blocking position and does not move. At this time, the loading valve core 13 moves to the open position, so that the liquid enters the loading valve core 13 through the loading valve port 1121, realizing the loading working process, and is discharged through the loading liquid outlet 115.When the liquid is loaded to a certain pressure, it is necessary to unload the liquid. The electromagnetic pilot valve 20 controls the pilot valve core to switch from the loading position to the unloading position. At this time, the second pilot port 213 is connected to the third pilot port 214, so that the liquid in the back-pressure pilot chamber 116 flows into the third pilot port 214 through the second pilot port 213, discharging the liquid in the back-pressure pilot chamber 116. Moreover, after all the liquid in the back-pressure pilot chamber 116 is discharged, since the first pilot port 212 is not conducting and no other liquid flows into the electromagnetic pilot valve 20, the tendency of the electromagnetic pilot valve 20 to be contaminated can be reduced while ensuring the normal operation of the unloading valve. At this time, the liquid pressure at the unloading valve port 1111 is greater than the liquid pressure in the back-pressure pilot chamber 116. At this time, the unloading valve core 12 moves to open the unloading valve port 1111, and the liquid enters the unloading valve core 12 through the unloading valve port 1111 for unloading and is discharged through the unloading liquid outlet 114. And the loading valve core 13 is in the blocking position, avoiding the simultaneous operation of the loading valve core 13 and the unloading valve core 12, and improving the sustainability of the unloading valve operation. With the above structure, by setting the electromagnetic pilot valve 20 to control the main valve 10 to unload or load, it is convenient to achieve automatic control, and the unloading valve is redesigned to ensure the reliability of the unloading valve core 12. By setting the pilot channel 117, the flow rate of the electromagnetic pilot valve 20 can be greatly reduced, reducing the tendency of the electromagnetic pilot valve 20 to be contaminated.

[0041] It should be noted that the third pilot port 214 is connected to the outside, including the following two structures. The first is that when unloading the liquid, the third pilot port 214 is directly connected to the unloading liquid outlet 114, and the liquid in the back-pressure pilot chamber 116 is discharged through the unloading liquid outlet 114, thereby reducing the liquid pressure at one end of the back-pressure pilot chamber 116, and then causing the unloading valve core 12 to move to unload. The second is that the third pilot port 214 is directly connected to the outside, and the liquid in the back-pressure pilot chamber 116 is directly discharged to the outside, thereby realizing the unloading working process.

[0042] Among them, in the prior art, as Figures 1 to 3 shown, the unloading valve generally consists of a main valve body 11', an electromagnetic pilot valve 20' and a mechanical pilot valve 1'. The unloading valve includes a loading valve core 13' and an unloading valve core 12'. The electromagnetic pilot valve 20' and the mechanical pilot valve 1' jointly control the unloading valve to load or unload. When loading, both the electromagnetic pilot valve 20' and the mechanical pilot valve 1' are in the cut-off position, and the liquid enters the loading pipeline 63' through the loading valve core 13'. When unloading is required, the electromagnetic pilot valve 20' switches from the loading position to the unloading position, and the ejector rod 2' inside the mechanical pilot valve 1 moves, causing the mechanical pilot valve 1 to open. The electromagnetic pilot valve 20' and the mechanical pilot valve 1' are both kept open, and the liquid enters the unloading pipeline 62' for unloading.

[0043] Specifically, the mechanical pilot valve 1' is difficult to machine and has a high failure rate. To increase the trouble-free operation time of the unloading valve, the mechanical pilot valve 1' is cancelled in this embodiment. The unloading pressure and the recovery pressure are controlled by the electronic control system, and the unloading valve core 12 is redesigned to prevent the cavitation failure of the unloading valve core 12 during normal sealing.

[0044] Among them, by using the pilot channel 117 to direct part of the liquid to flow into the backpressure pilot chamber 116, the over-flow rate of the electromagnetic pilot valve 20 can be greatly reduced, the tendency of the electromagnetic pilot valve 20 to be contaminated can be reduced, the trouble-free operation time of the precision pilot can be increased, and the inside of the unloading valve core 12 that cooperates with the backpressure pilot chamber 116 is a hollow structure, which can reduce the weight of the unloading valve core 12, facilitating both the reduction of production costs and the replacement of the unloading valve core 12.

[0045] As Figure 5 and Figure 8 shown, the main valve 10 further includes an unloading valve sleeve 14 disposed in the unloading valve chamber 111. The unloading valve port 1111 is provided at the lower end of the unloading valve sleeve 14. The unloading valve core 12 is movably disposed through the unloading valve sleeve 14. An unloading diversion hole 141 communicating with the unloading liquid outlet 114 is disposed through the side wall of the unloading valve sleeve 14. With the above structure, when unloading the liquid, the unloading valve core 12 can move to the unloading position on the unloading valve sleeve 14. The unloading valve sleeve 14 can guide the movement of the unloading valve core 12, and the unloading diversion hole 141 is disposed on the side wall of the unloading valve sleeve 14, enabling the liquid to flow into the unloading liquid outlet 114 under the action of the unloading diversion hole 141. The unloading valve sleeve 14 plays a role in guiding and sealing the liquid flow and supports the unloading valve core 12.

[0046] As Figure 5 and Figure 8 shown, the unloading valve sleeve 14 includes an unloading guide sleeve 142 and an unloading diversion sleeve 143 connected to the lower end of the unloading guide sleeve 142. The outer side wall of the unloading valve core 12 is in clearance fit with the inner side wall of the unloading guide sleeve 142. The unloading valve port 1111 is provided at the lower end of the unloading diversion sleeve 143. The unloading diversion hole 141 is disposed on the side wall of the unloading diversion sleeve 143. With the above structure, the unloading valve core 12 moves within the unloading guide sleeve 142. The outer side wall of the unloading valve core 12 is in clearance fit with the inner side wall of the unloading guide sleeve 142, facilitating the relative movement of the unloading valve core 12. By disposing the unloading diversion hole 141 on the unloading diversion sleeve 143, the unloading guide sleeve 142 and the unloading diversion sleeve 143 are designed separately, facilitating maintenance and assembly and reducing production costs.

[0047] As Figure 12 and Figure 13As shown in the figure, a circumferentially extending annular positioning groove 1421 is provided at the lower end of the unloading guide sleeve 142, and an annular positioning boss 1431 is provided at the upper end of the unloading diversion sleeve 143. The annular positioning boss 1431 is fitted into the annular positioning groove 1421. With the above structure, by the mutual cooperation between the annular positioning groove 1421 and the annular positioning boss 1431, the unloading guide sleeve 142 can be installed behind the unloading diversion sleeve 143, which is convenient for installation.

[0048] As Figure 5 and Figure 6 shown in the figure, the main valve 10 further includes a positioning pin 15. A first positioning hole 1422 is provided at the upper end of the unloading guide sleeve 142, and the main valve body 11 has a second positioning hole 118 opposite to the first positioning hole 1422. The positioning pin 15 is inserted into the first positioning hole 1422 and the second positioning hole 118. With the above structure, the positioning pin 15 can fix the unloading guide sleeve 142. The positioning pin 15 cooperates with the first positioning hole 1422 on the unloading guide sleeve 142, and the first positioning hole 1422 positions the installation of the positioning pin 15. And to ensure the stability of the device, the second positioning hole 118 is provided on the main valve body 11, which can prevent the positioning pin 15 from falling off due to insecure installation, so as to ensure the normal operation of the unloading valve core 12.

[0049] As Figure 5 , Figure 8 and Figure 12 shown in the figure, a plurality of unloading diversion holes 141 are provided on the side wall of the unloading valve sleeve 14. The plurality of unloading diversion holes 141 are arranged at intervals along the circumference of the unloading valve sleeve 14, and at least one of the plurality of unloading diversion holes 141 is arranged opposite to the unloading liquid outlet 114. By providing a plurality of unloading diversion holes 141 on the side wall of the unloading valve sleeve 14, it is convenient to install the unloading valve sleeve 14, so that the unloading diversion holes 141 can be correctly aligned with the unloading liquid outlet 114. When unloading the liquid, it can not only ensure the liquid flow rate, but also be convenient for processing and assembly.

[0050] As Figure 5 and Figure 8 shown in the figure, an annular diversion groove 121 extending along the circumference is provided on the outer side wall of the unloading valve core 12. The annular diversion groove 121 is arranged opposite to the unloading diversion holes 141. By providing the annular diversion groove 121, the flow area of the liquid at the unloading liquid outlet 114 can be increased, avoiding too fast flow rates on the inner surface of the unloading valve sleeve 14 and the circumferential surface of the unloading valve core 12 during unloading, and preventing cavitation.

[0051] It should be noted that in the prior art, an elastic member 3' is provided at the upper end of the unloading valve core 12', and the elastic force of the elastic member 3' is used to reset the unloading valve core 12'. However, due to the provision of the elastic member 3', the unloading valve core 12' cannot be fully opened under the influence of the elastic force of the elastic member 3' during unloading, resulting in cavitation of the unloading valve core 12', thereby affecting the operation of the emulsion pump station. In this application, there is no elastic member above the unloading valve core 12, which can fully open the unloading valve core 12 and effectively increase the liquid passing space.

[0052] As Figure 5 , Figure 8 and Figure 11 shown, the main valve 10 further includes a loading valve seat 16 provided in the loading valve cavity 112. The loading valve core 13 is movably inserted through the loading valve seat 16. The loading valve port 1121 is provided at the upper end of the loading valve seat 16. The side wall of the loading valve seat 16 has a through-set loading diversion hole 161, and the loading diversion hole 161 is disposed opposite to the loading liquid outlet 115. With the above structure, when loading the liquid, the loading valve core 13 can move to the loading position within the loading valve seat 16. The loading valve seat 16 can guide the movement of the loading valve core 13, and a loading diversion hole 161 is provided on the side wall of the loading valve seat 16, so that the liquid can flow into the loading liquid outlet 115 under the action of the loading diversion hole 161. The loading valve seat 16 plays a role in guiding and sealing the liquid flow, and also plays a supporting role for the loading valve core 13.

[0053] As Figure 10 and Figure 11 shown, the loading diversion hole 161 is a long strip-shaped hole 1611 extending along the circumferential direction of the loading valve seat 16. By providing the long strip-shaped hole 1611, it is ensured that the liquid flows into the loading liquid outlet 115 through the long strip-shaped hole 1611, and by using the long strip-shaped hole 1611, the liquid passing area can be increased and the throttling can be reduced.

[0054] As Figure 10 and Figure 11 shown, a plurality of loading diversion holes 161 are provided on the side wall of the loading valve seat 16, and the plurality of loading diversion holes 161 are arranged at intervals along the circumferential direction of the loading valve seat 16. By providing a plurality of loading diversion holes 161 on the side wall of the loading valve seat 16, it is convenient to install the loading valve seat 16. The loading diversion holes 161 can be correctly aligned with the loading liquid outlet 115, so that when the loading valve core 13 loads the liquid, it can not only ensure the liquid flow rate, but also be convenient for processing and assembly.

[0055] As Figure 5 , Figure 8 , Figure 10 and Figure 11As shown, the main valve 10 further includes a loading guide sleeve 17 disposed within the loading valve seat 16. The loading valve core 13 includes a guide rod 131 and a sealing plate 132 disposed at the upper end of the guide rod 131. The sealing plate 132 can open or block the loading valve port 1121. The loading guide sleeve 17 has a guide hole 171, and the guide rod 131 is inserted into the guide hole 171. The outer side wall of the guide rod 131 is in clearance fit with the hole wall of the guide hole 171. With the above structure, the loading valve core 13 can move within the loading guide sleeve 17. When liquid flows into the loading valve seat 16, the liquid pressure pushes the guide rod 131 downward, and the sealing plate 132 and the guide rod 131 cooperate with each other so that the sealing plate 132 can move downward and open the loading valve port 1121, ensuring that the main valve 10 can perform loading. The outer side wall of the guide rod 131 is in clearance fit with the hole wall of the guide hole 171, which not only facilitates the relative movement of the guide rod 131 but also facilitates maintenance and assembly, reducing production costs.

[0056] It should be noted that the overall design of the loading valve core 13 is beneficial to ensuring the fitting precision and reducing the occurrence of faults.

[0057] As Figure 5 、 Figure 8 and Figure 11 shown, the main valve 10 further includes a return spring 18. The return spring 18 is sleeved on the guide rod 131. The upper end of the return spring 18 abuts against the lower surface of the sealing plate 132, and the lower end of the return spring 18 abuts against the upper surface of the loading guide sleeve 17. By providing the return spring 18 on the guide rod 131, during the process of the main valve 10 stopping the loading operation, in order to prevent liquid backflow, under the action of the liquid pressure and the elastic force of the return spring 18, it can drive the sealing plate 132 and the guide rod 131 to move upward, thereby ensuring that the sealing plate 132 can block the loading valve port 1121, and the sealing plate 132 can be kept in the blocking position under the action of the return spring 18.

[0058] As Figure 5 and Figure 8 shown, the main valve body 11 includes a main valve body 31, a first valve cover 32, and a second valve cover 33. The unloading valve cavity 111 is disposed at the upper end of the main valve body 31, the loading valve cavity 112 is disposed at the lower end of the main valve body 31, the main valve liquid inlet 113 is disposed on the side wall of the main valve body 31, and the back pressure pilot cavity 116 is disposed on the lower end surface of the first valve cover 32. The first valve cover 32 covers the upper end of the main valve body 31, and the second valve cover 33 covers the lower end of the main valve body 31. With the above structure, the first valve cover 32 covers the upper end of the main valve body 31, and the second valve cover 33 covers the lower end of the main valve body 31, which can play a role in sealing and limiting the unloading valve core 12 and the loading valve core 13, facilitating assembly.

[0059] As Figure 9As shown in the figure, the unloading valve further includes a pressure sensor 40 and an electric control unit 50. The pressure sensor 40 is disposed at the loading liquid outlet 115, and the electric control unit 50 is electrically connected to the pressure sensor 40 and the electromagnetic pilot valve 20 respectively. By providing the pressure sensor 40 and the electric control unit 50, the pressure sensor 40 can detect the pressure at the loading liquid outlet 115. When the detected pressure at the loading liquid outlet 115 reaches the set value, the electric control unit 50 can control the pilot spool in the electromagnetic pilot valve 20 to switch from the loading position to the unloading position, facilitating the automatic control of the unloading valve.

[0060] It should be noted that during the initial operation of the unloading valve, since there is no pressure in the loading pipeline 63, the electric control unit 50 controls the electromagnetic pilot valve 20 to be energized. The liquid enters the intersection of the unloading spool 12 and the loading spool 13 through the main valve liquid inlet 113. The liquid at the main valve liquid inlet 113 passes through the pilot filter 61 and reaches the first pilot port 212 of the electromagnetic pilot valve 20, and then enters the backpressure pilot chamber 116 through the second pilot port 213. Since the liquid pressure in the backpressure pilot chamber 116 is greater than the liquid pressure at the unloading valve port 1111, the unloading spool 12 remains stationary without moving. The liquid enters the loading pipeline 63 through the loading spool 13 for liquid loading. When the pressure sensor 40 detects that the pressure is greater than the set value, the electric control unit 50 controls the electromagnetic pilot valve 20 to switch from the loading position to the unloading position. The pressure in the backpressure pilot chamber 116 of the unloading spool 12 decreases, and the unloading spool 12 moves. The main valve liquid inlet 113 is communicated with the unloading liquid outlet 114, the pressure decreases, and the loading spool 13 closes under the action of the return spring 18. At this time, unloading is performed. When the hydraulic support operates, the pressure in the loading pipeline 63 will decrease. When the pressure sensor 40 detects that the pressure decreases to the recovery pressure, the electric control unit 50 controls the electromagnetic pilot valve 20 to switch to the loading position, and so on in a cycle.

[0061] As Figure 9 shown in the figure, when the electromagnetic pilot valve 20 is energized, the pilot spool is in the loading position, and when the electromagnetic pilot valve 20 is de-energized, the pilot spool is in the unloading position. With the above structure, when the electromagnetic pilot valve 20 is energized, the pilot spool is in the loading position, and the loading spool 13 works to load the liquid. When the pressure sensor 40 detects that the pressure reaches the set value, the electromagnetic pilot valve 20 can be controlled by the electric control unit 50 to switch from the loading position to the unloading position, facilitating automatic operation. Moreover, with the safety design of energizing the electromagnetic pilot valve 20 for loading and de-energizing for unloading, accidents can be prevented.

[0062] It should be noted that the electric control component 50 and the pressure sensor 40 monitor the pressure of the hydraulic system in real time. Before the unloading pressure is reached, the electric control component 50 controls the electromagnetic pilot valve 20 to be energized. When the pressure sensor 40 detects that the pressure is higher than the unloading pressure, the electric control component 50 controls the electromagnetic pilot valve 20 to be de-energized. Until the pressure of the hydraulic system drops below the restoring force, the electric control component 50 controls the electromagnetic pilot valve 20 to be energized again, and so on in a cycle.

[0063] The device provided by the embodiment has the following beneficial effects:

[0064] (1) By setting the electromagnetic pilot valve 20, it is convenient to automatically control the loading or unloading of the main valve 10. The electromagnetic pilot valve 20 has a pilot valve body 21, and the pilot valve core in the pilot valve body 21 is arranged in the pilot valve cavity 211, so that the pilot valve core can be switched between the loading position and the unloading position;

[0065] (2) By arranging the unloading diversion hole 141 on the unloading diversion sleeve 143, the unloading guide sleeve 142 and the unloading diversion sleeve 143 are designed separately, which is convenient for maintenance and assembly and reduces production costs;

[0066] (3) When the liquid flows into the loading valve seat 16, the liquid pressure pushes the guide rod 131 to move downward, and the sealing plate 132 cooperates with the guide rod 131 so that the sealing plate 132 can move downward and open the loading valve port 1121, ensuring that the main valve 10 can be loaded. The outer side wall of the guide rod 131 and the hole wall of the guide hole 171 are in clearance fit, which is not only convenient for the relative movement of the guide rod 131 but also convenient for maintenance and assembly;

[0067] (4) By setting the pressure sensor 40 and the electric control component 50, the pressure sensor 40 can detect the pressure at the loading liquid outlet 115. When the detected pressure at the loading liquid outlet 115 reaches the set value, the electric control component 50 can control the pilot valve core in the electromagnetic pilot valve 20 to switch from the loading position to the unloading position, which is convenient for the automatic control of the unloading valve.

[0068] For the convenience of understanding the prior art, such as Figures 1 to 3As shown, the unloading valve generally consists of a main valve body 11', an electromagnetic pilot valve 20', a mechanical pilot valve 1' and a pilot filter 61'. The main valve body 11' is composed of a loading valve core 13' and an unloading valve core 12'. When pressure liquid is used for loading, at this time both the electromagnetic pilot valve 20' and the mechanical pilot valve 1' are in the cut-off position. There is pilot pressure at both the left and right ends of the unloading valve core 12'. At this time, the pressure is balanced and the unloading valve core 12' remains closed, and the liquid enters the loading pipeline 63' through the loading valve core 13'. When the pressure reaches a certain value, the electric control component issues an instruction to make the electromagnetic pilot valve 20' lose power and switch positions to open. The pressure in the pilot circuit where the electromagnetic pilot valve 20' is located decreases. At the same time, the pressure on the left side of the ejector rod 2' in the mechanical pilot valve 1' decreases, but the pressure on the right side of the ejector rod 2' does not decrease. A pressure difference is generated at both ends of the ejector rod 2', causing the ejector rod 2' to move to the left, overcoming the elastic force of the elastic component 3' in the mechanical pilot valve 1', and the mechanical pilot valve 1' switches positions to open. The electromagnetic pilot valve 20' and the mechanical pilot valve 1' both remain open, and the liquid pressure in this pilot circuit remains in a low-pressure state. At this time, the pressure on the left end of the unloading valve core 12' decreases, the unloading valve core 12' opens, the pressure decreases, and the loading valve core 13' closes due to the return spring 18' and the liquid pressure. At this time, the pressure liquid generated by the emulsion pump returns to the liquid tank. When the pressure of the hydraulic support system decreases to another value, the electric control component issues an instruction to make the electromagnetic pilot valve 20' get power and switch positions to close. The pressure in the pilot circuit where the electromagnetic pilot valve 20' is located increases. At the same time, the pressure on the left side of the ejector rod 2' of the mechanical pilot valve 1' increases. At a certain moment, the pressure difference generated at both ends of the ejector rod 2' is not enough to overcome the elastic force of the elastic component 3' in the mechanical pilot valve 1', and the mechanical pilot valve 1' switches positions to close. The electromagnetic pilot valve 20' and the mechanical pilot valve 1' simultaneously increase the liquid pressure in this pilot circuit, causing the pressure on the left side of the unloading valve core 12' to increase, and finally causing the unloading valve core 12' to close. After the pressure liquid increases, it overcomes the hydraulic pressure of the loading valve core 13' and the return spring 18' and continues to supply liquid to the hydraulic support system.

[0069] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0070] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the description. In all the examples shown and discussed here, any specific values should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, further discussion thereof is not required in subsequent drawings.

[0071] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom", etc. are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description. Without contrary description, these orientation terms do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus cannot be construed as limiting the protection scope of the present invention; the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0072] For ease of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above" can be used here to describe the spatial positional relationships of one device or feature to other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the drawings. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations will be made for the spatial relative descriptions used here.

[0073] In addition, it should be noted that the use of words such as "first", "second", etc. to limit components is only for the convenience of differentiating the corresponding components. Without otherwise stating, the above words have no special meanings, and thus cannot be construed as limiting the protection scope of the present invention.

[0074] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A pressure relief valve, characterized in that, the pressure relief valve comprises: a main valve (10), including a main valve body (11), a pressure relief valve core (12) and a loading valve core (13). The main valve body (11) has a pressure relief valve cavity (111), a loading valve cavity (112) and a main valve liquid inlet (113) located between the pressure relief valve cavity (111) and the loading valve cavity (112). One end of the pressure relief valve cavity (111) has a pressure relief valve port (1111) communicating with the main valve liquid inlet (113). The pressure relief valve core (12) is movably arranged in the pressure relief valve cavity (111) to open or block the pressure relief valve port (1111). One end of the loading valve cavity (112) has a loading valve port (1121) communicating with the main valve liquid inlet (113). The loading valve core (13) is movably arranged in the loading valve cavity (112) to open or block the loading valve port (1121). The main valve body (11) also has a pressure relief liquid outlet (114) communicating with the pressure relief valve cavity (111) and a loading liquid outlet (115) communicating with the loading valve cavity (112); an electromagnetic pilot valve (20), including a pilot valve body (21) and a pilot valve core. The pilot valve body (21) has a pilot valve cavity (211) and a first pilot port (212), a second pilot port (213) and a third pilot port (214) communicating with the pilot valve cavity (211). The pilot valve core has a loading position and a pressure relief position to connect the second pilot port (213) with the first pilot port (212), or to connect the second pilot port (213) with the third pilot port (214); wherein, one end of the main valve body (11) far from the pressure relief valve port (1111) has a back pressure pilot cavity (116) communicating with the pressure relief valve cavity (111). The cross-sectional dimension of the back pressure pilot cavity (116) is larger than that of the pressure relief valve port (1111). The main valve body (11) has a pilot channel (117). One end of the pilot channel (117) is connected to the pressure relief valve port (1111), and the other end of the pilot channel (117) is connected to the back pressure pilot cavity (116). The main valve liquid inlet (113) or the pressure relief liquid outlet (114) is connected to the first pilot port (212). The second pilot port (213) is connected to the back pressure pilot cavity (116). The third pilot port (214) is connected to the outside. When the pilot valve core is in the loading position, the second pilot port (213) is connected to the first pilot port (212). When the pilot valve core is switched from the loading position to the pressure relief position, the second pilot port (213) is connected to the third pilot port (214).

2. The pressure relief valve according to claim 1, characterized in that, The main valve (10) further includes a unloading valve sleeve (14) disposed in the unloading valve cavity (111). The unloading valve port (1111) is disposed at the lower end of the unloading valve sleeve (14). The unloading valve core (12) is movably disposed through the unloading valve sleeve (14). A unloading diversion hole (141) communicating with the unloading liquid outlet (114) is disposed through the side wall of the unloading valve sleeve (14).

3. The unloading valve according to claim 2, wherein, the unloading valve sleeve (14) includes a unloading guiding sleeve (142) and a unloading diversion sleeve (143) connected to the lower end of the unloading guiding sleeve (142). The outer side wall of the unloading valve core (12) is in clearance fit with the inner side wall of the unloading guiding sleeve (142). The unloading valve port (1111) is disposed at the lower end of the unloading diversion sleeve (143). The unloading diversion hole (141) is disposed on the side wall of the unloading diversion sleeve (143).

4. The unloading valve according to claim 3, wherein, a circumferentially extending annular positioning groove (1421) is disposed at the lower end of the unloading guiding sleeve (142). An annular positioning boss (1431) is disposed at the upper end of the unloading diversion sleeve (143). The annular positioning boss (1431) is embedded in the annular positioning groove (1421); and / or, the main valve (10) further includes a positioning pin (15). A first positioning hole (1422) is disposed at the upper end of the unloading guiding sleeve (142). The main valve body (11) has a second positioning hole (118) disposed opposite to the first positioning hole (1422). The positioning pin (15) is inserted into the first positioning hole (1422) and the second positioning hole (118).

5. The unloading valve according to claim 2, wherein, a plurality of the unloading diversion holes (141) are disposed on the side wall of the unloading valve sleeve (14). The plurality of unloading diversion holes (141) are arranged at intervals along the circumference of the unloading valve sleeve (14). At least one of the plurality of unloading diversion holes (141) is disposed opposite to the unloading liquid outlet (114); and / or, a circumferentially extending annular diversion groove (121) is disposed on the outer side wall of the unloading valve core (12). The annular diversion groove (121) is disposed opposite to the unloading diversion hole (141).

6. The unloading valve according to any one of claims 1 to 5, wherein, the main valve (10) further includes a loading valve seat (16) disposed in the loading valve cavity (112). The loading valve core (13) is movably disposed through the loading valve seat (16). The loading valve port (1121) is disposed at the upper end of the loading valve seat (16). A loading diversion hole (161) is disposed through the side wall of the loading valve seat (16). The loading diversion hole (161) is disposed opposite to the loading liquid outlet (115).

7. The unloading valve according to claim 6, wherein, The loading diversion hole (161) is a strip-shaped hole (1611) extending along the circumference of the loading valve seat (16); and / or, A plurality of the loading diversion holes (161) are provided on the side wall of the loading valve seat (16), and the plurality of loading diversion holes (161) are arranged at intervals along the circumference of the loading valve seat (16).

8. The unloading valve according to claim 6, characterized in that The main valve (10) further includes a loading guide sleeve (17) disposed within the loading valve seat (16). The loading valve core (13) includes a guide rod (131) and a sealing plate (132) disposed at the upper end of the guide rod (131). The sealing plate (132) can open or block the loading valve port (1121). The loading guide sleeve (17) has a guide hole (171), the guide rod (131) is inserted into the guide hole (171), and a clearance fit is provided between the outer side wall of the guide rod (131) and the hole wall of the guide hole (171); The main valve (10) further includes a return spring (18). The return spring (18) is sleeved on the guide rod (131). The upper end of the return spring (18) abuts against the lower surface of the sealing plate (132), and the lower end of the return spring (18) abuts against the upper surface of the loading guide sleeve (17).

9. The unloading valve according to any one of claims 1 to 5, characterized in that The main valve body (11) includes a main valve body (31), a first valve cover (32), and a second valve cover (33). The unloading valve cavity (111) is provided at the upper end of the main valve body (31), the loading valve cavity (112) is provided at the lower end of the main valve body (31), the main valve liquid inlet (113) is provided on the side wall of the main valve body (31), the back pressure pilot cavity (116) is provided on the lower end surface of the first valve cover (32), the first valve cover (32) covers the upper end of the main valve body (31), and the second valve cover (33) covers the lower end of the main valve body (31).

10. The unloading valve according to any one of claims 1 to 5, characterized in that The unloading valve further includes a pressure sensor (40) and an electric control unit (50). The pressure sensor (40) is disposed at the loading liquid outlet (115), and the electric control unit (50) is electrically connected to the pressure sensor (40) and the electromagnetic pilot valve (20) respectively; and / or, When the electromagnetic pilot valve (20) is energized, the pilot valve core is in the loading position, and when the electromagnetic pilot valve (20) is de-energized, the pilot valve core is in the unloading position.

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