A pilot emergency relief valve special for nuclear power unit

Abstract

This application relates to a pilot-operated emergency pressure relief valve specifically for nuclear power units, comprising a main valve body and a pilot valve. A pressure-sensing pipe is provided between the main valve body and the pilot valve, and the main valve body and the pilot valve are interconnected through the pressure-sensing pipe. An exhaust port is provided on the pilot valve, and a pressure closing assembly is installed inside the pilot valve. The pressure closing assembly opens or closes the exhaust port by sliding. The pressure closing assembly includes a mounting plate, a spring element, a pressure piston block, a pressure sensor, and a trigger switch. The mounting plate is installed inside the pilot valve, and the spring element is disposed inside the pilot valve, with one end of the spring element abutting against the mounting plate. The pressure piston block is fixed to the end of the spring element facing away from the mounting plate and is slidably disposed inside the pilot valve. The pressure sensor is mounted on the mounting plate, and the elastic force of the spring element acts on the pressure sensor. The trigger switch is installed inside the pilot valve; when the pressure piston block slides to open the exhaust port, the trigger switch is pressed. This application has the effect of conveniently monitoring the start-up pressure of the pilot-operated pressure relief valve in real time.

Description

Technical Field

[0001] This application relates to the field of pipeline valve bodies, and in particular to a pilot-operated emergency pressure relief valve specifically for nuclear power units. Background Technology

[0002] A pilot-operated emergency pressure relief valve, also known as a pilot-operated safety pressure relief valve, is a non-direct-acting safety protection valve that controls the opening and closing of the main valve through a pilot valve. It belongs to the category of automatic valves and is mainly used for overpressure protection in boilers, pressure vessels, and pipeline systems. When the medium pressure exceeds the set value, the pilot valve drives the main valve to open and discharge the medium. It automatically closes after the pressure drops. It includes two types: micro-opening and full-opening, and can be classified into closed and open types according to its structure.

[0003] Pilot-operated emergency pressure relief valves are important safety devices in nuclear power equipment, mainly used for overpressure protection of the reactor loop system. They drive the main valve to discharge the medium through the rapid response of the pilot valve, ensuring that the system pressure is always within the safe threshold.

[0004] Pilot-operated emergency pressure relief valves need to have their opening pressure checked periodically after a period of use to prevent the opening pressure from being too high or too low, which would prevent pressure relief at the correct pressure. However, if the pilot-operated emergency pressure relief valve is damaged during the period of regular inspection, causing a change in the opening pressure, it can easily lead to safety hazards due to overpressure protection during the entire period. Summary of the Invention

[0005] To facilitate real-time monitoring of the start-up pressure of the pilot-operated pressure relief valve, this application provides a pilot-operated emergency pressure relief valve specifically for nuclear power units.

[0006] The pilot-operated emergency pressure relief valve for nuclear power units provided in this application adopts the following technical solution: A pilot-operated emergency pressure relief valve for nuclear power units includes a main valve body and a pilot valve. A pressure-feeding pipe is provided between the main valve body and the pilot valve, and the main valve body and the pilot valve are interconnected through the pressure-feeding pipe. The pilot valve has an exhaust port and a pressure closing assembly is provided inside the pilot valve. The pressure closing assembly opens or closes the exhaust port by sliding. The pressure closing assembly includes a mounting plate, a spring element, a pressure piston block, a pressure sensor, and a trigger switch. The mounting plate is installed inside the pilot valve. The spring element is disposed inside the pilot valve, with one end of the spring element abutting against the mounting plate. The pressure piston block is fixed to the end of the spring element away from the mounting plate and is slidably disposed inside the pilot valve. The exhaust port is opened or closed by sliding. The pressure sensor is installed on the mounting plate, and the spring force of the spring element acts on the pressure sensor. The trigger switch is installed inside the pilot valve. When the pressure piston block slides to open the exhaust port, the trigger switch is pressed.

[0007] By adopting the above technical solution, the pressure sensor and trigger switch detect the starting pressure of the driving pressure piston block when the exhaust port is opened. When the trigger switch is pressed and the starting pressure detected by the pressure sensor is lower or higher than the preset value, it indicates that the structure inside the pilot valve is damaged and needs to be replaced or repaired in time. The setting of the pressure sensor and trigger switch makes it convenient to understand the starting pressure of the pilot relief valve in real time, reducing the probability of equipment damage and safety accidents.

[0008] Optionally, the mounting plate includes an upper plate and a lower plate, both of which are installed inside the pilot valve. The pressure sensor is installed on the side of the upper plate facing the lower plate, and the lower plate is slidably mounted on the upper plate, abutting against the pressure sensor. An elastic element abuts against the side of the lower plate away from the pressure sensor.

[0009] By adopting the above technical solution, the lower plate pressing against the pressure sensor can more accurately apply the elastic element to the pressure sensor, thereby improving the detection accuracy of the pressure sensor.

[0010] Optionally, the pilot valve has an opening and closing opening at its top, and an opening and closing plate is detachably installed at the opening and closing opening. The opening and closing opening can be opened by removing the opening and closing plate.

[0011] By adopting the above technical solution, the opening and closing settings can facilitate the opening of the pilot valve to inspect or replace the pressure closing component when the starting pressure is higher or lower than the preset value.

[0012] Optionally, a limiting ring is fixed inside the pilot valve, and the pressure piston block abuts against the limiting ring when closing the exhaust port.

[0013] By adopting the above technical solution, the setting of the limit ring can restrict the slippage of the pressure piston block, reduce the pressure piston block from slipping and closing the pressure-sensing pipeline connecting the pilot valve and the main valve body, thereby reducing the impact of the pressure piston block on the pressure-sensing pipeline.

[0014] Optionally, the opening and closing plate is threaded with an adjusting bolt, which abuts against the side of the upper plate away from the lower plate.

[0015] By adopting the above technical solution, the force required for the sliding of the driving pressure piston block can be adjusted by rotating the adjusting bolt to compress or expand the elastic element, thereby adjusting the opening pressure. This allows the pilot valve to be suitable for different pressure requirements, and it can also be used to continue operating the pilot valve when the opening pressure is different from the preset pressure.

[0016] Optionally, the pressure-sensing pipeline includes a flow pipe and a return pipe. One end of the flow pipe is fixed to the liquid inlet end of the main valve body, and the other end is detachably installed on the pilot valve. One end of the return pipe is installed at the liquid outlet end of the main valve body, and the other end is detachably installed on the pilot valve.

[0017] By adopting the above technical solution, the pilot valve can be detached from the main valve body through the detachable connection between the pilot valve and the drain pipe and the return pipe, so that the pilot valve can be easily replaced when it is damaged.

[0018] Optionally, a connecting assembly is provided between the drainage tube and the pilot valve. The connecting assembly includes a connecting tube and a connecting screw sleeve. The connecting tube is fixed to the pilot valve, and the connecting screw sleeve is slidably sleeved on the end of the drainage tube that connects to the pilot valve. The connecting screw sleeve is connected to the connecting tube by a rotating thread.

[0019] By adopting the above technical solution, the connection component can facilitate the disassembly and assembly of the pilot valve and the drain pipe.

[0020] Optionally, a flow-stopping mechanism is provided at one end of the drain pipe connected to the pilot valve. The flow-stopping mechanism includes a flow-stopping plate, a flow-stopping wedge, and a flow-stopping rod. Several flow-stopping plates are provided and are slidably disposed inside the drain pipe. Several flow-stopping wedges are provided and are fixed on the flow-stopping plates respectively. Several flow-stopping rods are provided and are slidably disposed on the drain pipe. One end of the flow-stopping rod abuts against the flow-stopping wedge, and the other end extends out of the drain pipe. The flow-stopping rod slides toward the flow-stopping wedge, driving the flow-stopping plate to close the internal channel of the drain pipe.

[0021] By adopting the above technical solution, the flow-stopping mechanism can cut off the drain pipe after the pilot valve is disassembled, reducing the probability of medium leakage from the drain pipe.

[0022] Optionally, the flow-stopping rod extends out of the drain pipe from the side of the connecting screw sleeve away from the pilot valve. After the connecting screw sleeve is separated from the connecting pipe, the flow-stopping rod is driven to slide toward the flow-stopping wedge under the action of gravity.

[0023] By adopting the above technical solution, the flow-stopping rod is set towards the connecting screw sleeve, which can drive the flow-stopping mechanism to cut off the diversion pipe by its own gravity when the connecting screw sleeve is detached from the connecting pipe. This ensures that the diversion valve can be cut off when the pilot valve is disassembled, reducing the probability of media leakage caused by the operator forgetting to cut off the diversion valve.

[0024] Optionally, an inspection port is provided on the top of the main valve body, and a sealing plate can be detachably installed on the inspection port.

[0025] By adopting the above technical solution, the opening of the inspection port facilitates the inspection and maintenance of the main valve body.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. The pressure sensor and trigger switch detect the starting pressure of the driving pressure piston block when the exhaust port is opened. When the trigger switch is pressed and the starting pressure detected by the pressure sensor is lower or higher than the preset value, it indicates that the structure inside the pilot valve is damaged and needs to be replaced or repaired in time. By setting the pressure sensor and trigger switch, it is convenient to understand the starting pressure of the pilot relief valve in real time, reducing the probability of equipment damage and safety accidents. 2. The opening and closing settings allow the pilot valve to be opened for maintenance or replacement of the pressure closing assembly when the starting pressure is higher or lower than the preset value. The setting of the limit ring can restrict the sliding of the pressure piston block, reduce the pressure piston block sliding and closing the pressure tapping pipeline connecting the pilot valve and the main valve body, thereby reducing the impact of the pressure piston block on the pressure tapping pipeline. 3. By rotating the adjusting bolt, the force required to slide the driving pressure piston block can be adjusted to compress or expand the elastic element, thereby adjusting the opening pressure. This allows the pilot valve to be adapted to different pressure requirements. It can also be adjusted to allow the pilot valve to continue to be used when the opening pressure is different from the preset pressure. 4. The pilot valve can be detached from the main valve body through the detachable connection between the pilot valve and the drain pipe and the return pipe, so that the pilot valve can be easily replaced when it is damaged; 5. The flow-stopping mechanism can cut off the drain pipe after the pilot valve is disassembled, reducing the probability of medium leakage from the drain pipe; the flow-stopping rod is set towards the connecting screw sleeve, and can drive the flow-stopping mechanism to cut off the drain pipe by its own gravity when the connecting screw sleeve is detached from the connecting pipe, thereby ensuring that the drain valve can be cut off when the pilot valve is disassembled, reducing the probability of medium leakage caused by the operator forgetting to cut off the drain valve; 6. The opening of the inspection port facilitates the inspection and maintenance of the main valve body. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0028] Figure 2 This is a cross-sectional view of the overall structure of an embodiment of this application.

[0029] Figure 3 yes Figure 2 A magnified view of section A in the middle.

[0030] Figure 4 yes Figure 2 A magnified view of section B in the middle.

[0031] Explanation of reference numerals in the attached diagram: 1. Main valve body; 2. Pilot valve; 3. Pressure tapping pipe; 31. Drain pipe; 32. Return pipe; 4. Inlet; 5. Outlet; 6. Valve plug; 7. Exhaust port; 8. Pressure closing assembly; 81. Mounting plate; 811. Upper plate; 812. Lower plate; 82. Spring element; 83. Pressure piston block; 84. Pressure sensor; 85. Trigger switch; 9. Opening / closing opening; 10. Opening / closing plate; 11. Limit ring; 12. Adjusting bolt; 13. Connecting assembly; 131. Connecting pipe; 132. Connecting threaded sleeve; 14. Flow-stopping mechanism; 141. Flow-stopping plate; 142. Flow-stopping wedge; 143. Flow-stopping rod; 15. Inspection port; 16. Sealing plate; 17. Blocking plate. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0033] First, it should be noted that in the description of this application, the use of directional terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" indicates the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for descriptive purposes and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the use of numerical quantifiers such as "first," "second," and "third" is for descriptive purposes only and should not be construed as indicating or implying relative importance. Additionally, in this application, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, interference fits, transition fits, or integral connections; they can refer to direct connections or indirect connections through an intermediate medium. Therefore, those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0034] This application discloses a pilot-operated emergency pressure relief valve specifically for nuclear power units, referring to... Figure 1 and Figure 2The system includes a main valve body 1 and a pilot valve 2. A pressure-feeding pipe 3 is provided between the main valve body 1 and the pilot valve 2. The main valve body 1 and the pilot valve 2 are interconnected through the pressure-feeding pipe 3. One end of the main valve body 1 has a bottom inlet 4, and the side of the main valve body 1 has an outlet 5. A valve plug 6 is slidably installed inside the main valve body 1. The valve plug 6 can open or close the inlet 4 and the outlet 5 by sliding. The pilot valve 2 has an exhaust port 7. A pressure closing assembly 8 is provided inside the pilot valve 2. The pressure closing assembly 8 can open or close the exhaust port 7 by sliding. The pressure closing assembly 8 includes a mounting plate 81, a spring element 82, a pressure piston block 83, a pressure sensor 84, and a trigger switch 85. The mounting plate 81 is installed inside the pilot valve 2. A spring element 82 is installed inside the pilot valve 2. In this embodiment, the spring element 82 is a spring. One end of the spring element 82 abuts against the mounting plate 81. A pressure piston block 83 is fixed to the end of the spring element 82 facing away from the mounting plate 81. The pressure piston block 83 is slidably installed inside the pilot valve 2. It opens or closes the exhaust port 7 by sliding. A pressure sensor is installed on the mounting plate 81. The elastic force of the spring element 82 acts on the pressure sensor 84. A trigger switch 85 is installed inside the pilot valve 2. When the pressure piston block 83 slides to open the exhaust port 7, the trigger switch 85 is pressed, connecting one end of the inlet 4 of the main valve body 1 to the pipeline of the nuclear power equipment. Then, the outlet 5 of the main valve body 1 is connected to the receiving and processing equipment for the pressure relief medium. In the nuclear power plant's processing equipment, when the medium flows normally through the pipelines, it enters the pilot valve 2 through the pressure-sensing pipeline 3 and then returns to the main valve body 1. The medium acts on the valve plug 6 in the main valve body 1, restricting its sliding and connecting the inlet 4 and outlet 5 of the main valve body 1. When the pressure of the medium in the nuclear power plant is higher than the opening pressure in the pilot valve 2, the medium drives the pressure piston block 83 to slide and open the exhaust port 7, allowing the medium to be discharged from the exhaust port 7. At this time, the pressure supplied by the medium on the valve plug 6 is relieved, and the medium in the nuclear power plant drives the valve plug 6 to slide and connect the inlet 4 and outlet 5 of the main valve body 1 for depressurization and discharge. When the pressure drops to a safe value, the pressure piston block 83 returns under the action of the elastic element 82. When the exhaust port 7 is closed, the medium flows back into the main valve body 1 through the pressure-sensing pipe 3, restricting the sliding of the valve plug 6. At the same time, as the pressure piston block 83 slides to open the exhaust port 7, the pressure piston block 83 presses the trigger switch 85. Simultaneously, the pressure sensor 84 detects the starting pressure of the pressure piston block 83 when it is opened. When the starting pressure detected by the pressure sensor 84 is lower or higher than the preset value when the trigger switch 85 is pressed, it indicates that the structure inside the pilot valve 2 is damaged and needs to be replaced or repaired in time. The setting of the pressure sensor 84 and the trigger switch 85 makes it convenient to understand the starting pressure of the pilot-operated pressure relief valve in real time, reducing the probability of equipment damage and safety accidents.

[0035] Reference Figure 2 and Figure 3The mounting plate 81 includes an upper plate 811 and a lower plate 812. Both the upper plate 811 and the lower plate 812 are installed inside the pilot valve 2. The pressure sensor 84 is installed on the side of the upper plate 811 facing the lower plate 812. The lower plate 812 is slidably mounted on the upper plate 811 and abuts against the pressure sensor 84. The elastic element 82 abuts against the side of the lower plate 812 away from the pressure sensor 84. When the elastic elements 82 act on the pressure sensor 84, the uneven distribution of the driving force of the elastic elements 82 can easily lead to inaccurate values ​​detected by the pressure sensor 84. By pressing the lower plate 812 against the pressure sensor 84, all the driving force of the elastic elements 82 can be applied to the lower plate 812, and the force can be evenly applied to the pressure sensor 84, thereby improving the detection accuracy of the pressure sensor 84.

[0036] Reference Figure 2 and Figure 3 The pilot valve 2 has an opening 9 at its top, and an opening 10 is detachably installed at the opening 9. Removing the opening 10 opens the opening 9. The opening 9 allows the pilot valve 2 to be easily opened for inspection or replacement of the pressure closing assembly 8 when the starting pressure is higher or lower than a preset value. A limiting ring 11 is fixed inside the pilot valve 2. When the pressure piston block 83 closes the exhaust port 7, it abuts against the limiting ring 11. The limiting ring 11 restricts the sliding of the pressure piston block 83, reducing the risk of the pressure piston block 83 sliding and closing the pilot valve 2 and the main valve. The pressure-sensing pipe 3 connected to the body 1 reduces the influence of the pressure piston block 83 on the pressure-sensing pipe 3; the opening and closing plate 10 is threaded with an adjusting bolt 12, which abuts against the side of the upper plate 811 away from the lower plate 812. By rotating the adjusting bolt 12, the force required to drive the pressure piston block 83 to slide can be adjusted to compress or expand the elastic element 82, thereby adjusting the force required to adjust the opening pressure. This allows the pilot valve 2 to be used for different pressure requirements, and it can also be adjusted to continue using the pilot valve 2 when the opening pressure is different from the preset pressure.

[0037] Reference Figure 2 and Figure 4The pressure-sensing pipe 3 includes a drain pipe 31 and a return pipe 32. One end of the drain pipe 31 is fixed to the liquid inlet end of the main valve body 1, and the other end is detachably installed on the pilot valve 2. One end of the return pipe 32 is installed at the liquid outlet end of the main valve body 1, and the other end is detachably installed on the pilot valve 2. The detachable connection between the drain pipe 31 and the return pipe 32 and the pilot valve 2 allows the pilot valve 2 to be removed from the main valve body 1, thus facilitating the replacement of the pilot valve 2 when it is damaged. The drain pipe 31 is connected to the pilot valve 2 and the return pipe 32. A connecting assembly 13 is provided at the connection point between the pilot valve 2 and the pilot valve 2. The connecting assembly 13 includes a connecting pipe 131 and a connecting threaded sleeve 132. The connecting pipe 131 is fixed on the pilot valve 2, and the connecting threaded sleeve 132 is slidably sleeved on one end of the drain pipe 31 that connects to the pilot valve 2. The connecting threaded sleeve 132 is connected to the connecting pipe 131 by rotational thread. The connecting assembly 13 can facilitate the disassembly and assembly between the pilot valve 2 and the drain pipe 31, as well as between the pilot valve 2 and the return pipe 32, thereby facilitating the replacement of the pilot valve 2 when it is damaged.

[0038] Reference Figure 2 and Figure 4 A flow-stopping mechanism 14 is provided at one end of the drainage pipe 31 connected to the pilot valve 2. The flow-stopping mechanism 14 includes a flow-stopping plate 141, a flow-stopping wedge 142, and a flow-stopping rod 143. Several flow-stopping plates 141 are provided. In this embodiment, six flow-stopping plates 141 are provided. The flow-stopping plates 141 are slidably disposed inside the drainage pipe 31. The flow-stopping plates 141 open or cut off the internal flow channel of the drainage pipe 31 by sliding. Several flow-stopping wedges 142 are provided. In this embodiment, six flow-stopping wedges 142 are provided. The six flow-stopping wedges 142 are fixed on the six flow-stopping plates 141 respectively. Several flow-stopping rods 143 are provided. In this embodiment, six flow-stopping rods 143 are provided. All six flow-stopping rods 143 are slidably disposed on the drainage pipe 31. The flow-stopping rods 143 are disposed corresponding to the flow-stopping wedges 142, and one end of the flow-stopping rod 143 abuts against the flow-stopping wedge 142. 2. The other end extends out of the drain pipe 31. The throttling rod 143 slides toward the throttling wedge 142 to drive the throttling plate 141 to close the internal channel of the drain pipe 31. The throttling mechanism 14 can cut off the drain pipe 31 after the pilot valve 2 is disassembled, reducing the probability of the medium leaking out of the drain pipe 31. The throttling rod 143 extends out of the drain pipe 31 on the side of the connecting sleeve 132 away from the pilot valve 2. After the connecting sleeve 132 is separated from the connecting pipe 131, it drives the throttling rod 143 to slide toward the throttling wedge 142 under the action of gravity. The throttling rod 143 is set toward the connecting sleeve 132. When the connecting sleeve 132 is separated from the connecting pipe 131, it can drive the throttling mechanism 14 to cut off the drain pipe 31 by its own gravity, thereby ensuring that the drain valve can be cut off when the pilot valve 2 is disassembled, reducing the probability of the medium leaking out due to the operator forgetting to cut off the drain valve.

[0039] Reference Figure 1 and Figure 2The main valve body 1 has an inspection port 15 on its top, and a sealing plate 16 is detachably installed on the inspection port 15. The inspection port 15 facilitates the inspection of the inside of the main valve body 1. A sealing plate 17 is provided at the inlet 4 of the main valve body 1. The sealing plate 17 slides to block the internal passage of the inlet 4. The sealing plate 17 can block the inlet 4 when the inside of the main valve body 1 is damaged. Then, the sealing plate 16 is removed to inspect the inside of the main valve body 1. After the inspection is completed, the sealing plate 16 is reinstalled on the main valve body 1. Then, the inlet 4 is opened by sliding the sealing plate 17 to resume normal use of the main valve body 1. When the sealing plate 17 slides to open the inlet 4, the sealing plate 17 extends out of the main valve body 1 and covers the inlet 4 of the main valve body 1, limiting the probability of the bolts connecting the inlet 4 of the main valve body 1 coming loose.

[0040] The implementation principle of this application embodiment is as follows: The pilot valve 2 is installed on the main valve body 1. The pilot valve 2 is connected to the main valve body 1 via the pressure-sensing pipe 3. Then, the starting pressure of the pressure piston block 83 is adjusted by adjusting bolt 12. The pressure sensor 84 and trigger switch 85 are connected to a computer to monitor their status. The main valve body 1 is then installed on the reactor's circuit system. The inlet 4 of the main valve body 1 is opened by sliding sealing plate 17, completing the installation of the pilot-operated emergency pressure relief valve. When the reactor's circuit system... When the pressure exceeds the start-up pressure of the pilot valve 2, the pressure-driven pressure piston block 83 slides to open the exhaust port 7, the pressure acting on the valve plug 6 on the pressure-sensing pipeline 3 is relieved, and the valve plug 6 is opened to release pressure. At the same time as the pressure piston block 83 slides to open the exhaust port 7, the pressure piston block 83 presses the trigger switch 85. The computer detects whether the pressure detected on the pressure sensor 84 is the same as the preset start-up pressure when the trigger switch 85 is triggered. When the detected start-up pressure is different from the preset pressure, the computer informs the staff to adjust or repair the equipment through feedback.

[0041] It should be noted that the above embodiments are only used to illustrate this application and are not intended to limit the technical solutions described in this application. Although this specification has described this application in detail with reference to the above embodiments, those skilled in the art should understand that they can still make modifications or equivalent substitutions to this application. All technical solutions and improvements that do not depart from the spirit and scope of this application should be covered within the scope of the claims of this application.

Claims

1. A pilot-operated emergency pressure relief valve for nuclear power units, comprising a main valve body (1) and a pilot valve (2), wherein a pressure-feeding pipe (3) is provided between the main valve body (1) and the pilot valve (2), the main valve body (1) and the pilot valve (2) are interconnected and communicate with each other through the pressure-feeding pipe (3), an exhaust port (7) is provided on the pilot valve (2), and a pressure closing assembly (8) is provided inside the pilot valve (2), wherein the pressure closing assembly (8) opens or closes the exhaust port (7) by sliding, characterized in that: The pressure closing assembly (8) includes a mounting plate (81), an elastic element (82), a pressure piston block (83), a pressure sensor (84), and a trigger switch (85). The mounting plate (81) is installed inside the pilot valve (2). The elastic element (82) is located inside the pilot valve (2), with one end of the elastic element (82) abutting against the mounting plate (81). The pressure piston block (83) is fixed to one end of the elastic element (82) away from the mounting plate (81). The pressure piston block (83) is slidably located inside the pilot valve (2) and opens or closes the exhaust port (7) by sliding. The pressure sensor is installed on the mounting plate (81), and the elastic force of the elastic element (82) acts on the pressure sensor (84). The trigger switch (85) is installed inside the pilot valve (2). When the pressure piston block (83) slides to open the exhaust port (7), the trigger switch (85) is pressed.

2. The pilot-operated emergency pressure relief valve for nuclear power units according to claim 1, characterized in that: The mounting plate (81) includes an upper plate (811) and a lower plate (812). Both the upper plate (811) and the lower plate (812) are installed inside the pilot valve (2). The pressure sensor (84) is installed on the side of the upper plate (811) facing the lower plate (812). The lower plate (812) is slidably disposed on the upper plate (811) and abuts against the pressure sensor (84). The elastic element (82) abuts against the side of the lower plate (812) away from the pressure sensor (84).

3. A pilot-operated emergency pressure relief valve for nuclear power units according to claim 2, characterized in that: The pilot valve (2) has an opening and closing opening (9) at the top. An opening and closing plate (10) is detachably installed at the opening and closing opening (9). The opening and closing opening (9) is opened by removing the opening and closing plate (10).

4. A pilot-operated emergency pressure relief valve for nuclear power units according to claim 3, characterized in that: The pilot valve (2) is fixed with a limiting ring (11), and the pressure piston block (83) abuts against the limiting ring (11) when closing the exhaust port (7).

5. A pilot-operated emergency pressure relief valve for nuclear power units according to claim 4, characterized in that: The opening and closing plate (10) is threaded with an adjusting bolt (12), which abuts against the side of the upper plate (811) away from the lower plate (812).

6. A pilot-operated emergency pressure relief valve for nuclear power units according to claim 1, characterized in that: The pressure-sensing pipe (3) includes a flow pipe (31) and a return pipe (32). One end of the flow pipe (31) is fixed to the liquid inlet end of the main valve body (1), and the other end is detachably installed on the pilot valve (2). One end of the return pipe (32) is installed at the liquid outlet end of the main valve body (1), and the other end is detachably installed on the pilot valve (2).

7. A pilot-operated emergency pressure relief valve for nuclear power units according to claim 6, characterized in that: A connecting assembly (13) is provided between the drainage tube (31) and the pilot valve (2). The connecting assembly (13) includes a connecting tube (131) and a connecting threaded sleeve (132). The connecting tube (131) is fixed on the pilot valve (2). The connecting threaded sleeve (132) is slidably sleeved on one end of the drainage tube (31) connected to the pilot valve (2). The connecting threaded sleeve (132) is connected to the connecting tube (131) by a rotating thread.

8. A pilot-operated emergency pressure relief valve for nuclear power units according to claim 7, characterized in that: The diversion pipe (31) is connected to the pilot valve (2) and a flow-stopping mechanism (14) is provided at one end. The flow-stopping mechanism (14) includes a flow-stopping plate (141), a flow-stopping wedge (142), and a flow-stopping rod (143). Several flow-stopping plates (141) are provided and are slidably disposed inside the diversion pipe (31). Several flow-stopping wedges (142) are provided and are fixed on the flow-stopping plate (141) respectively. Several flow-stopping rods (143) are provided and are slidably disposed on the diversion pipe (31). One end of the flow-stopping rod (143) abuts against the flow-stopping wedge (142) and the other end extends out of the diversion pipe (31). The flow-stopping rod (143) slides toward the flow-stopping wedge (142) to drive the flow-stopping plate (141) to close the internal channel of the diversion pipe (31).

9. A pilot-operated emergency pressure relief valve for nuclear power units according to claim 8, characterized in that: The flow-stopping rod (143) extends out of the drain pipe (31) on the side of the connecting sleeve (132) away from the pilot valve (2). After the connecting sleeve (132) is separated from the connecting pipe (131), the flow-stopping rod (143) is driven to slide toward the flow-stopping wedge (142) under the action of gravity.

10. A pilot-operated emergency pressure relief valve for nuclear power units according to claim 1, characterized in that: The main valve body (1) has an inspection port (15) on its top, and a sealing plate (16) is detachably installed on the inspection port (15).

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