Pilot operated safety valve

Abstract

The present application relates to the field of valve, specifically relates to a pilot safety valve, including a main valve and a redundant design of multiple spring pilot control circuit;The main valve is a medium self-driven pilot valve with a built-in main valve piston cylinder, and the multiple spring pilot control circuits are installed on the main valve body, each spring pilot control circuit includes a manual isolation valve, a safety manifold valve and an electromagnetic isolation valve, the safety manifold valve is an integrated whole of a safety valve and a manifold valve, the manual isolation valve connects the main valve pressure tapping hole before the main valve with the safety valve, realizing the isolation and on-off control of the main valve pressure before the valve, and the electromagnetic isolation valve connects the main valve pilot control hole of the main valve piston upper cavity with the manifold valve pilot control hole of the manifold valve, realizing the isolation and on-off control of the main valve piston upper cavity and the manifold valve pilot control hole passage. Each spring pilot control circuit can realize the automatic control of the opening and closing of the main valve, and is redundant to each other, improving the reliability of the safety opening of the main valve.

Description

Technical Field

[0001] This invention relates to the field of valves, and more specifically to pilot-operated safety valves. Background Technology

[0002] The pressurizer safety valves of the advanced third-generation "Hualong One" pressurized water reactor nuclear power plant have large diameters and operate under high temperatures and pressures, placing higher demands on valve control and reliability. Therefore, a new type of pilot-operated pressurizer safety valve needs to be designed that is compact, easy to disassemble and assemble, integrates pressure tapping and control, has adjustable set pressure, signal feedback, multiple redundant control functions, high reliability, and high seismic resistance. Furthermore, it needs to be capable of performing functions such as hot overpressure protection, cold overpressure protection, charging and discharging functions, and manual pressure relief after an accident. Summary of the Invention

[0003] Based on the aforementioned prior art, the purpose of this invention is to provide a pilot-operated safety valve for use in the pressurizer of the advanced third-generation "Hualong One" pressurized water reactor nuclear power plant. Under high temperature, high pressure, and large-diameter operating conditions, it features a compact structure, easy disassembly and assembly, integrated pressure tapping and control, adjustable set pressure, signal feedback, multiple redundant control (dual redundant automatic control, manual and automatic remote control, and pure manual control), high reliability, and high seismic resistance.

[0004] To achieve the above objectives, the technical solution adopted by this invention is as follows: a pilot-operated safety valve, comprising a main valve and a redundantly designed multi-row spring pilot control circuit; the main valve is a medium-driven pilot-operated valve with a built-in main valve piston cylinder, and the multi-row spring pilot control circuits are all installed on the main valve body. Each row of spring pilot control circuits includes a manual isolation valve, a safety manifold valve, and an electromagnetic isolation valve. The safety manifold valve is an integrated unit of the safety valve and the manifold valve. The manual isolation valve connects the main valve pressure tap in front of the main valve to the safety valve, thereby achieving isolation and conduction control of the pressure path in front of the main valve. The electromagnetic isolation valve connects the main valve pilot control hole in the upper chamber of the main valve piston to the manifold valve pilot control hole of the manifold valve, thereby achieving isolation and conduction control of the passage between the upper chamber of the main valve piston and the manifold valve pilot control hole.

[0005] Furthermore, the electromagnetic isolation valve is normally open and closes when energized, thereby isolating the pilot control port passage of the main valve and realizing the control of closing the main valve.

[0006] Furthermore, the electromagnetic isolation valve is equipped with a switch to provide signal feedback on the on / off position of the electromagnetic isolation valve.

[0007] Furthermore, the safety valve is equipped with open and close limit switches to provide signal feedback on the open / closed position of the safety valve.

[0008] Furthermore, the spring pilot control loop consists of two columns, which are symmetrical in structure.

[0009] Furthermore, after the pressure before the main valve reaches the pressure value set by the safety valve, the safety valve opens and pressure is conducted into the manifold until the opening pressure of the manifold is reached, putting the manifold in the open state. This allows the medium pressure in the pilot control circuit of the upper chamber of the main valve piston to be discharged through the outlet of the manifold. The main valve opens under the action of different medium pressures in the upper and lower chambers of the piston and remains in the open state. After the pressure before the main valve decreases to the reseating pressure value of the safety valve, the safety valve reseats and closes. The pressure after the safety valve is discharged and reduced through the outlet of the manifold until the manifold automatically closes under the combined action of the manifold spring, the weight of the manifold valve disc, and the remaining medium pressure in the pilot control circuit of the upper chamber of the main valve piston. This causes the pilot control circuit pressure in the upper chamber of the main valve piston to gradually increase to the medium pressure, achieving pressure balance in the upper and lower chambers of the piston. The main valve then closes under the combined action of the main valve spring and the weight of the main valve disc assembly.

[0010] Furthermore, the pilot-operated safety valve also includes an electromagnetic pilot control circuit, which is installed on the main valve body.

[0011] Furthermore, the electromagnetic pilot control circuit includes an electromagnetic pilot valve consisting of two electromagnetic valves connected in series, which is directly connected to the main valve pilot control port in the upper chamber of the main valve piston.

[0012] Furthermore, both solenoid valves are normally closed and open when energized.

[0013] Furthermore, each of the two solenoid valves is equipped with a solenoid valve switch to provide signal feedback on the switching status of the solenoid valves.

[0014] Furthermore, the pilot-operated safety valve also includes a manual pilot control circuit, which is installed on the main valve body.

[0015] Furthermore, the manual pilot control circuit includes a manual isolation valve, which is directly connected to the main valve pilot control port in the upper chamber of the main valve piston. The manual isolation valve is normally closed.

[0016] Furthermore, the safety manifold valve includes a safety manifold valve body, a safety valve cover, a safety valve stem, a manifold valve cover, a manifold valve disc, and a manifold valve piston rod; the safety manifold valve body has a safety valve cavity, a lower manifold valve cavity, and an upper manifold valve cavity; the safety valve pressure tap is connected to the safety valve cavity; the upper manifold valve cavity is connected to the pilot control hole of the manifold valve; a manifold valve piston cylinder is disposed in the lower manifold valve cavity; the safety valve cavity is connected to the inner cavity of the manifold valve piston cylinder; the safety valve cover is installed on the safety manifold valve body; The safety valve stem passes through the safety valve cover, extends into the safety valve cavity, and is capable of axial displacement relative to the safety valve cover along the safety valve stem; the manifold valve cover is installed on the safety manifold valve body; the manifold valve disc is located in the upper cavity of the manifold valve, and a manifold valve spring is disposed between the manifold valve disc and the manifold valve cover; one end of the manifold valve piston rod abuts against the manifold valve disc, and the other end cooperates with the outlet of the manifold valve piston cylinder, and the manifold valve piston rod is provided with a piston portion disposed inside the manifold valve piston cylinder.

[0017] Furthermore, the manual isolation valve connects the main valve pressure tap in front of the main valve with the safety valve pressure tap.

[0018] Furthermore, a safety valve spring sleeve is fixed to the upper part of the safety valve cover, and a safety valve adjusting screw is screwed onto the upper part of the safety valve spring sleeve; an upper safety valve spring seat and a lower safety valve spring seat are sleeved on the outside of the safety valve stem, and a safety valve spring is disposed between the upper safety valve spring seat and the lower safety valve spring seat; the upper safety valve spring seat abuts against the bottom of the safety valve adjusting screw, and the lower safety valve spring seat abuts against the safety valve stem.

[0019] Furthermore, the safety valve spring sleeve is fixed with a safety valve limit switch seat, and a switch assembly is provided on the upper part of the safety valve limit switch seat. The switch assembly includes a micro switch, which is used to adjust the open and closed positions according to the height and stroke of the safety valve stem.

[0020] Furthermore, the micro switch is wired and connected to the safety valve electrical connector, the safety valve electrical connector is fixed to the safety valve limit switch cover, the safety valve limit switch cover is fixed to the safety valve limit switch seat, and the safety valve electrical connector is a quick-plug sealed structure.

[0021] Furthermore, the safety valve cavity is connected to a first pressure test port, and the first pressure test port is provided with a first safety valve blind flange that is detachably connected to the safety manifold valve body; The safety valve pressure tap is connected to a second test port, and the second test port is provided with a second safety valve blind flange that is detachably connected to the safety manifold valve body.

[0022] Furthermore, a first spiral wound gasket is provided between the first safety valve blind flange and the safety manifold valve body; a second spiral wound gasket is provided between the second safety valve blind flange and the safety manifold valve body.

[0023] Furthermore, a safety valve adjusting nut is screwed onto the lower part of the safety valve cover. The outer circumference of the safety valve adjusting nut has multiple straight teeth evenly distributed around its periphery. The safety valve adjusting bolt can rotate to adjust the safety valve adjusting nut. The safety valve adjusting nut is threadedly connected to a safety valve adjusting sleeve. Adjusting the safety valve adjusting bolt controls the gap between the safety valve adjusting sleeve and the safety manifold valve body.

[0024] Furthermore, a safety valve positioning nut is screwed onto the lower part of the safety valve stem to control the opening height of the safety valve discharge.

[0025] Furthermore, a third spiral wound gasket is provided between the manifold valve cover and the safety manifold valve body.

[0026] Furthermore, a safety valve sealing assembly is provided between the safety valve stem and the safety valve cover. The safety valve sealing assembly includes a safety valve packing gasket and a safety valve packing stacked from bottom to top, and a safety valve packing pressure plate that is detachably connected to the safety valve cover is stacked on top of the safety valve packing.

[0027] Further, the main valve includes a main valve body, which internally forms a medium inlet flow channel, a main valve cavity, and a medium outlet flow channel, and these three are interconnected; the upper end of the main valve body is connected to the main valve cover via a bolt assembly, and a main valve bracket is mounted on the upper end of the main valve cover via a bolt assembly, the main valve bracket being equipped with a valve opening / closing position and opening degree detection mechanism; a valve seat is welded onto the main valve body, and a main valve disc assembly is disposed in the main valve cavity located above the valve seat, with a disc connector at the upper end of the disc assembly, and a main valve spring mechanism is mounted on the upper end of the disc connector, and the main valve stem is connected... Connected to the valve disc connector, the top of the main valve stem passes through the main valve spring mechanism and extends beyond the upper end of the main valve cover to reach the main valve support position. A temperature detection device is installed on the main valve body located in the medium inlet flow channel. The outer surface of the main valve body corresponding to the temperature detection device is the outer inclined surface of the main valve body. The two planes adjacent to the outer inclined surface of the main valve body are the front and rear of the main valve body, and the plane opposite to the outer inclined surface of the main valve body is the side of the main valve body. Main valve pressure taps are provided on the front and rear of the main valve body, and main valve pilot control holes are provided on the front, rear, and side of the main valve body. The main valve adopts a pilot-operated, self-driven structure with an internal main valve piston cylinder.

[0028] Furthermore, the main valve pressure tap and main valve pilot control port, which serve as a dual redundant spring pilot control circuit, are arranged in a symmetrical mirror structure at the front and rear of the main valve body.

[0029] Furthermore, positioning pin holes and fastening threaded holes are arranged near the main valve pressure taps at the front and rear of the main valve body, and near the main valve pilot control holes at the front, rear, and sides of the main valve body.

[0030] Furthermore, the main valve body adopts an integral forging structure with the inlet medium flow channel and the outlet medium flow channel forming a 45° angle.

[0031] Furthermore, the medium outlet flow channel of the main valve body has a gradually enlarging structure.

[0032] Furthermore, the main valve body is provided with an inlet flange and an outlet flange, respectively. The inlet flange opposite to the main valve body inlet is connected to the main valve body by butt welding to form the main body of the main valve body. The inlet flange is connected to the inlet mating flange by a bolt assembly, and the main valve body outlet is connected to the outlet flange by a bolt assembly.

[0033] Furthermore, a main valve spiral wound gasket is provided between the inlet flange and the inlet mating flange, and between the main valve body and the outlet flange, to ensure the sealing performance of the flange connection.

[0034] Specifically, grooves for accommodating sealing gaskets are provided on the end faces of the inlet mating flange and the outlet flange. A first main valve spiral wound gasket is installed in the groove of the inlet mating flange, and a second main valve spiral wound gasket is installed in the groove of the outlet flange. The first main valve spiral wound gasket, the inlet mating flange, and the bolt assembly are connected to the inlet flange, and the second main valve spiral wound gasket, the outlet flange, and the bolt assembly are connected to the outlet of the main valve body.

[0035] Furthermore, a main valve spiral wound gasket is provided at the junction of the upper end of the main valve body and the main valve cover. A groove is opened on the upper surface of the main valve body to accommodate the third main valve spiral wound gasket. The third main valve spiral wound gasket is pressed into the sealing groove on the upper surface of the main valve body by the main valve cover through a bolt assembly.

[0036] Furthermore, the main valve disc assembly includes: a main valve disc, a main valve piston cylinder, a stainless steel wear-resistant steel ring, an anti-loosening gasket, and an internal hexagonal head screw; the lower part of the main valve disc is a large end, and the top part is a small end connected to the valve disc connector. The outer diameter of the large end of the main valve disc mates with the main valve piston cylinder, and the outer diameter of the main valve piston cylinder mates with the inner wall of the main valve body; the upper end face of the main valve piston cylinder is connected to the main valve cover by a bolt assembly, and the center of the main valve cover has a receiving cavity for accommodating the main valve disc, the valve disc connector, and the main valve spring mechanism above it; the small end of the main valve disc mates with the receiving cavity of the main valve cover through a valve stem guide sleeve; the main valve disc has a medium flow channel, which includes a radially bent channel penetrating the lower and upper surfaces of the large end of the main valve disc, and an axial channel penetrating both horizontal ends of the large end of the main valve disc.

[0037] The lower section of the radially bent channel is equipped with an internal hexagonal head screw. The internal hexagonal head screw is positioned inside the lower section by an anti-loosening washer, and a throttling orifice for controlling the flow rate of the medium is opened at the center of the internal hexagonal head screw.

[0038] Based on the above scheme, the main valve disc integrates the functions of a normal valve disc and a piston, with the lower base part (large end) of the main valve disc serving as the functional part of the normal valve disc.

[0039] Furthermore, wear-resistant components are respectively provided between the outer diameter of the large end of the main valve disc and the inner diameter of the main valve piston cylinder, and between the small end of the main valve disc and the inner diameter of the valve stem guide sleeve. These components include a first stainless steel wear-resistant steel ring and a second stainless steel wear-resistant steel ring, and both stainless steel wear-resistant steel rings are installed in grooves opened on the main valve disc.

[0040] Furthermore, a wear-resistant component, a third stainless steel wear-resistant ring, is also provided between the outer diameter of the main valve piston cylinder and the inner wall of the main valve body, and this third stainless steel wear-resistant ring is installed in a groove opened on the outer diameter of the main valve piston cylinder.

[0041] Based on the wear-resistant component set between the outer diameter of the large end of the main valve disc and the inner diameter of the main valve piston cylinder, the first stainless steel wear-resistant steel ring has two sets on the outer diameter surface of the large end of the main valve disc, one above the other.

[0042] Furthermore, the valve stem guide sleeve is made of wear-resistant material and is screwed into the main valve cover by threads for assembly and cooperation with the main valve cover; the valve stem guide sleeve and the main valve piston cylinder together play a role in positioning the main valve disc and guiding its reciprocating motion.

[0043] Furthermore, the valve seat is welded to the main valve body according to a water seal structure layout, and the valve seat is configured with a gradually enlarging structure; the valve seat and the main valve body are welded together.

[0044] Furthermore, a sealing contact surface is formed between the upper end of the valve seat and the lower part of the main valve disc, and the sealing contact surface between the two is treated with hard alloy overlay welding.

[0045] Furthermore, the main valve spring mechanism includes: a main valve spring seat disposed on the valve disc connector and a main valve spring located on the main valve spring seat; the main valve spring seat is connected to the main valve disc through the valve disc connector, so that the main valve spring seat can move up and down and reciprocate with the main valve disc; one end of the main valve spring contacts and is positioned with the main valve spring seat, and the other end contacts and is positioned with the main valve cover.

[0046] Furthermore, the main valve stem is installed between the valve disc connector and the main valve spring seat, and moves up and down with the main valve disc, and leads the main valve disc switch position status to the outside of the valve, and the valve switch position and opening degree detection mechanism detects and provides signal feedback on the valve switch position and opening degree. Furthermore, a main valve packing sealing assembly is provided between the main valve stem and the main valve cover. The main valve packing sealing assembly includes a main valve packing pressure plate, a main valve packing sleeve, main valve packing, and a main valve packing gasket. The main valve packing pressure plate is located on the main valve stem above the main valve cover. A main valve packing cavity is provided between the main valve stem and the main valve cover below the main valve packing pressure plate. The main valve packing is pressed into the main valve packing cavity by the main valve packing sleeve, and a main valve packing gasket is provided at the bottom of the main valve packing cavity. Furthermore, the main valve packing sealing assembly is fastened above by a fastening assembly, which consists of a stud, a disc spring indicator needle, a disc spring indicator plate, a disc spring sleeve, a disc spring, a gasket, and a nut. This ensures the sealing reliability of the main valve stem and main valve packing under temperature and pressure changes and enables visual control of the fastening force.

[0047] Furthermore, the valve switch position and opening degree detection mechanism includes: a valve position indicator, an indicator rod, and a limit switch; the indicator rod is fixed to the upper end of the main valve stem by a nut and an anti-loosening washer, the main body of the valve position indicator is fixed to the main valve bracket, the magnetic head is fixed to the indicator rod, and the limit switch is fixed to the main valve bracket by an internal hexagonal head screw and a limit switch seat.

[0048] Furthermore, the temperature detection device is an embedded non-penetrating temperature sensor; the bolt assemblies mentioned above all adopt a combination structure of studs, nuts, and anti-loosening washers.

[0049] In the above structure of this solution, the front, rear and side of the main valve body are connected by four pilot holes to form the pilot circuit of the safety valve. The pilot circuit is connected to the upper chamber area of ​​the main valve piston cylinder in the main valve. The main valve adopts a pilot-operated self-driven structure with an internal main valve piston cylinder. The change in the pressure of the medium inside the main valve and the pilot circuit pressure in the upper chamber of the piston creates a change in the force on the piston, thereby realizing the opening and closing of the main valve. In the main valve body, the upper part of the large end of the main valve disc, together with the inner wall of the main valve piston cylinder and the lower end face of the main valve cover, forms a cavity gap. When the pressure difference between the medium pressure entering the main valve inlet and the medium pressure in the pilot circuit of the upper chamber of the piston changes, it forces the main valve disc assembly to reciprocate up and down. When the pressure inside the main valve body is greater than the pressure in the pilot circuit, the main valve disc assembly moves upward, causing the cavity gap located at the upper part of the large end of the main valve disc to gradually disappear, thereby causing the lower end of the main valve disc to disengage from the valve seat and form a gap, thus opening the valve. Conversely, when the pressure in the pilot circuit is close to or equal to the medium pressure of the main valve body, the main valve disc assembly moves downward, causing the lower end of the main valve disc to move closer to the valve seat, causing the cavity gap located at the upper part of the large end of the main valve disc to gradually recover, thus closing the valve.

[0050] The beneficial effects of this invention are as follows: The main valve adopts a pilot-operated, self-driven structure with a built-in piston cylinder, and both pressure tapping and pilot control are integrated into the main valve body, resulting in a reasonable spatial layout and compact structure. In the multi-row spring pilot control circuit, each circuit can be independently controlled by a safety valve with a pre-set pressure value to automatically control the opening and closing of the main valve. Furthermore, the multi-row spring pilot control circuits are redundant, improving the reliability of the main valve's safe opening. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the pilot-operated safety valve control principle of the present invention; Figure 2 This is a front view of the pilot-operated safety valve of the present invention; Figure 3 This is a left view of the pilot-operated safety valve of the present invention; Figure 4 This is a top view of the pilot-operated safety valve of the present invention; Figure 5 The three-dimensional view of the pilot-operated safety valve of the present invention Figure 1 ; Figure 6 The three-dimensional view of the pilot-operated safety valve of the present invention Figure 2 ; Figure 7 This is a schematic diagram of the main valve assembly (closed position) in the pilot-operated safety valve of the present invention. Figure 8 for Figure 7 Enlarged view of point A; Figure 9 for Figure 7 Enlarged view of point B; Figure 10 for Figure 7 Enlarged view of point C; Figure 11 for Figure 7 Enlarged view of point D; Figure 12 for Figure 7 Enlarged view of point E; Figure 13 for Figure 7 Enlarged view at point F; Figure 14 for Figure 7 Enlarged view of point G; Figure 15 This is a schematic diagram of the open position of the main valve in the pilot-operated safety valve of the present invention. Figure 16 This is a front view of the main valve in the pilot-operated safety valve of the present invention. Figure 17 This is a rear view of the main valve in the pilot-operated safety valve of the present invention. Figure 18 for Figure 17 The left view; Figure 19 for Figure 17 The right view; Figure 20 The three-dimensional view of the main valve in the pilot-operated safety valve of the present invention. Figure 1 ; Figure 21 The three-dimensional view of the main valve in the pilot-operated safety valve of the present invention. Figure 2 ; Figure 22 This is a schematic diagram of the safety manifold valve in the pilot-operated safety valve of the present invention; Figure 23 This is a partial cross-sectional view of the safety manifold valve in the pilot-operated safety valve of the present invention; Figure 24 This is a schematic diagram showing the location of the nameplate on the safety manifold valve in the pilot-operated safety valve of the present invention. Figure 25 for Figure 22 A magnified view of part A1 in the middle; Figure 26 for Figure 22 A magnified view of part B1 in the middle; Figure 27 for Figure 22 A magnified view of part C1 in the middle; Figure 28 This is a rear view of the safety manifold valve in the pilot-operated safety valve of the present invention; Figure 29 This is a left view of the safety manifold valve in the pilot-operated safety valve of the present invention; Figure 30 This is a right view of the safety manifold valve in the pilot-operated safety valve of the present invention; Figure 31 This is a perspective view of the safety manifold valve in the pilot-operated safety valve of the present invention; Figure 32 for Figure 23 Sectional view D1-D1 in the diagram.

[0052] In the picture: Appendix Figure 1-6 Corresponding principle icon number: MF, main valve; WQ, temperature sensor; K, switch (open); G, switch (closed); FQ, valve position indicator; TX1, First spring-piloted control circuit; GL1, First manual isolation valve; AH1, First safety manifold valve; DL1, First electromagnetic isolation valve; AF1, First safety valve; HF1, First manifold valve; K1, First safety valve limit switch open; G1, First safety valve limit switch closed; SY1, First test interface; TX2, Second spring-piloted control circuit; GL2, Second manual isolation valve; AH2, Second safety manifold valve; DL2, Second electromagnetic isolation valve; AF2, Second safety valve; HF2, Second manifold valve; K2, Second safety valve limit switch open; G2, Second safety valve limit switch closed; SY2, Second test interface; DX3, Electromagnetic pilot control circuit; DF, Electromagnetic pilot valve; KG31, First solenoid valve switch; KG32, Second solenoid valve switch; SX4, Manual pilot control circuit; GL4, Manual circuit manual isolation valve; N, entrance; X, exit.

[0053] Appendix Figure 7-31 Mechanical structure designation: 1. Main valve body; 101. Main valve body exterior bevel; 102. Front; 103. Rear; 104. Side; 105. Locating pin hole; 106. Fastening threaded hole; 2. Main valve cover; 3. Main valve bracket; 4. Valve seat; 5. Valve disc connector; 6. Main valve stem; 7. First main valve pressure tap; 8. Second main valve pressure tap; 9. First pilot hole; 10. Second pilot hole; 11. Third pilot hole; 12. Fourth pilot hole; 13. Inlet flange; 14. Outlet flange; 15. Inlet mating flange; 16. First main valve spiral wound gasket; 17. Second main valve spiral wound gasket; 18. Third main valve spiral wound gasket; 19. 191. Main valve disc; 20. Throttling orifice; 21. Main valve piston cylinder; 22. Anti-loosening gasket; 23. Socket head cap screw; 24. Valve stem guide sleeve; 25. First stainless steel wear-resistant steel ring; 26. Second stainless steel wear-resistant steel ring; 27. Third stainless steel wear-resistant steel ring; 28. Main valve spring seat; 29. ​​Main valve spring; 30. Main valve packing pressure plate; 31. Main valve packing; 32. Main valve packing gasket; 33. Fastening assembly; 34. Valve position indicator; 35. Indicator rod; 36. Limit switch; 37. Nut; 38. Socket head cap screw a; 39. Temperature sensor; 40. Cavity clearance; 100. Safety manifold valve body; 110. Safety valve cavity; 111. Safety valve pressure tap; 112. First test pressure port; 113. First safety valve blind flange; 114. Second test pressure port; 115. Second safety valve blind flange; 116. First spiral wound gasket; 117. Second spiral wound gasket; 120. Lower cavity of manifold valve; 121. Manifold valve piston cylinder; 122. Manifold valve blind flange; 123. Outlet; 124. Sixth spiral wound gasket; 130. Upper cavity of manifold valve; 131. Manifold valve pilot control port; 140. Fifth spiral wound gasket; 150. First pin hole; 160. Second pin hole; 170. First bolt through hole; 180. Second bolt through hole. 200. Safety valve cover; 210. Safety valve sealing assembly; 211. Safety valve packing gasket; 212. Safety valve packing; 213. Safety valve packing pressure plate; 220. Safety valve spring sleeve; 221. Safety valve adjusting screw; 222. Safety valve limit switch seat; 223. Safety valve lock nut. 300. Safety valve stem; 310. Safety valve adjusting sleeve; 320. Safety valve adjusting nut; 330. Safety valve adjusting bolt; 340. Fourth spiral wound gasket; 350. Safety valve positioning nut; 360. Safety valve spring; 361. Upper safety valve spring seat; 362. Lower safety valve spring seat. 400. Manifold valve cover; 410. Manifold valve spring; 420. Third spiral wound gasket. 500. Manifold valve disc, 600. Manifold valve piston rod; 610. Piston section; 700. Switch assembly; 710. Micro switch; 711. First safety valve limit switch bracket; 712. Second safety valve limit switch bracket; 720. Safety valve limit switch cover; 730. Safety valve electrical connector. 800. Manifold valve outlet flange; 810. Seventh spiral wound gasket. 900, nameplate; 910, rivet. Detailed Implementation

[0054] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0055] The pressurizer safety valve of the advanced third-generation "Hualong One" pressurized water reactor nuclear power plant has a large diameter and operates under high temperature and pressure, placing higher demands on valve control and reliability. Therefore, the design needs to consider performance requirements such as compact structure, ease of disassembly and assembly, integrated pressure tapping and control, adjustable set pressure, signal feedback, multiple redundant control functions (dual-redundant automatic control, manual and automatic remote control, and purely manual control), high reliability, and high seismic resistance. Furthermore, it needs to be a new type of pilot-operated pressurizer safety valve capable of performing functions such as hot overpressure protection, cold overpressure protection, charging and discharging functions, and manual pressure relief after an accident.

[0056] Example 1 See appendix Figure 1 The pilot-operated safety valve consists of a main valve MF, two spring-operated control loops (first spring-operated control loop TX1 and second spring-operated control loop TX2), one electromagnetic pilot-operated control loop DX3, and one manual pilot-operated control loop SX4. It can perform functions such as hot overpressure protection, cold overpressure protection, charging and discharging, and manual pressure relief after an accident. In the two spring-operated control loops TX1 / TX2, each loop can be independently controlled by a safety valve AF1 / AF2 with a pre-set pressure value to automatically control the opening and closing of the main valve MF. Furthermore, the two spring-operated control loops TX1 and TX2 are redundant, improving the reliability of the main valve MF's safe opening. The electromagnetic pilot-operated control loop DX3 can be manually or automatically remotely controlled via a detection and control system to control the opening and closing of the main valve, serving as a second control method (manual and automatic remote control) to further improve the reliability of the main valve MF's safe opening. The manual pilot control loop SX4 serves as the third control mode (purely manual control), further enhancing the reliability of the main valve MF's safe opening control, and acting as the final reliability guarantee for the main valve MF's opening control.

[0057] The main valve MF adopts a pilot-operated, self-driven structure with an internal piston cylinder. Pressure tapping and pilot control are integrated into the main valve body, resulting in a rational spatial layout and compact structure. The internal piston cylinder, assisted by the main valve spring, changes in internal medium pressure and pilot circuit pressure in the upper piston chamber create variations in the force exerted on the piston, thereby controlling the opening and closing of the main valve MF. The main valve MF body features a one-piece forged structure with a 45° angle between the inlet and outlet, facilitating the overall layout of the dome structure on site. Both the inlet and outlet of the main valve MF utilize a one-piece connection with mating flanges for easy installation and subsequent disassembly and inspection. The main valve MF is also equipped with a temperature sensor WQ, an open switch K, a closed switch G, and a valve position indicator FQ to provide signal feedback on the valve medium temperature and valve open / closed position.

[0058] The first spring-pilot control circuit TX1 is composed of the first manual isolation valve GL1, the first safety manifold valve AH1, and the first solenoid isolation valve DL1. The entire circuit is secured to the main valve body using bolts, nuts, and anti-loosening washers, forming a control circuit that controls the operation of the main valve MF. The first manual isolation valve GL1 connects the main valve pressure tap before the main valve MF to the first safety valve AF1, achieving isolation and conduction control of the pressure path before the main valve MF. The first solenoid isolation valve DL1 connects the main valve pilot control port of the upper chamber of the main valve MF piston to the manifold pilot control port of the first manifold valve HF1, achieving isolation and conduction control of the passage between the upper chamber of the main valve MF piston and the manifold pilot control port of the first manifold valve HF1. ​​Under normal conditions, the first solenoid isolation valve DL1 is in the open state, and the first safety manifold valve AH1 automatically controls the energization of the first spring-pilot control circuit TX1. When the first safety manifold valve AH1 malfunctions and fails to properly close the first spring-piloted control circuit TX1, the first solenoid isolation valve DL1 can be energized to isolate the main valve MF pilot control port, thereby controlling the closure of the main valve MF and improving the reliability of the first spring-piloted control circuit TX1 in controlling the main valve closure. Simultaneously, the first solenoid isolation valve DL1 is equipped with a first switch KG1 to provide signal feedback on its on / off position. The first safety manifold valve AH1 is composed of the first safety valve AF1 and the first manifold valve HF1 combined into a single unit, and the first safety valve is equipped with open K1 and closed G1 limit switches to provide signal feedback on its on / off position. The first safety manifold valve AH1 connects the main valve pressure tap before the main valve MF and the main valve pilot control port in the upper chamber of the main valve MF piston. When the pressure before the main valve MF reaches the pressure value set by the first safety valve AF1, the first safety valve AF1 opens, and the pressure is conducted to the first manifold valve HF1 until the opening pressure of the first manifold valve HF1 is reached, so that the first manifold valve HF1 is in the open state. Thus, the medium pressure in the pilot control circuit of the upper chamber of the main valve MF piston is discharged through the outlet of the first manifold valve HF1. ​​The main valve MF is opened under the action of different medium pressures in the upper and lower chambers of the piston and remains in the open state. Once the pressure before the main valve MF drops to the reseating pressure of the first safety valve AF1, the first safety valve AF1 reseated and closed. The pressure after the first safety valve AF1 was reduced through the outlet of the first manifold valve HF1 until the first manifold valve HF1 automatically closed under the combined action of the first manifold valve spring, the self-weight of the first manifold valve disc, and the remaining medium pressure in the pilot control circuit of the upper chamber of the main valve MF piston. As a result, the pressure in the pilot control circuit of the upper chamber of the main valve MF piston gradually increased to the medium pressure, achieving a balance between the pressures in the upper and lower chambers of the piston. The main valve MF closed under the combined action of the main valve spring and the self-weight of the main valve disc assembly.The first safety manifold valve AH1 is also equipped with a first test interface SY1, which allows for independent testing of the first spring-piloted control circuit TX1 by connecting an external pressure source after isolation by the first manual isolation valve GL1. Additionally, the first safety valve AF1 has an overall pressure regulation function, allowing the set pressure to be adjusted within a preset range as needed.

[0059] The second spring-piloted control circuit TX2 shares the same structural layout and control principle as the first spring-piloted control circuit TX1, and the two are symmetrically arranged. The second spring-piloted control circuit TX2 consists of the second manual isolation valve GL2, the second safety manifold valve AH2, and the second solenoid isolation valve DL2. The entire circuit is secured to the other side of the main valve body with bolts, nuts, and anti-loosening washers, forming another control circuit for controlling the operation of the main valve MF. The second manual isolation valve GL2 connects the main valve pressure tap before the main valve MF to the second safety valve AF2, achieving isolation and conduction control of the pressure path before the main valve MF. The second solenoid isolation valve DL2 connects the main valve pilot control hole in the upper chamber of the main valve MF piston and the manifold pilot control hole of the second manifold valve HF2, achieving isolation and conduction control of the path between the upper chamber of the main valve MF piston and the manifold pilot control hole of the second manifold valve HF2. When the second safety manifold valve AH2 malfunctions and fails to properly close the second spring-piloted control circuit TX2, the main valve pilot control port of the main valve MF can be isolated by energizing the second solenoid isolation valve DL2. This allows for control of the main valve MF to close, improving the reliability of the second spring-piloted control circuit TX2 in controlling the main valve's closure. Simultaneously, the second solenoid isolation valve DL2 is equipped with a second switch KG2 to provide feedback on its on / off position. The second safety manifold valve AH2 is composed of the second safety valve AF2 and the second manifold valve HF2 combined into a single unit. Furthermore, the second safety valve is equipped with limit switches K2 (open) and G2 (close) to provide feedback on its on / off position. The second safety manifold valve AH2 connects the main valve pressure tap before the main valve MF and the main valve pilot control port in the upper chamber of the main valve MF piston. When the pressure before the main valve MF reaches the pressure value set by the second safety valve AF2, the second safety valve AF2 opens, and the pressure is conducted to the second manifold valve HF2 until the opening pressure of the second manifold valve HF2 is reached, so that the second manifold valve HF2 is in the open state. Thus, the medium pressure in the pilot control circuit of the upper chamber of the main valve MF piston is discharged through the outlet of the second manifold valve HF2. The main valve MF is opened under the action of different medium pressures in the upper and lower chambers of the piston and remains in the open state. Once the pressure before the main valve MF drops to the reseating pressure of the second safety valve AF2, the second safety valve AF2 reseated and closed. The pressure after the second safety valve AF2 was reduced through the outlet of the second manifold valve HF2 until the second manifold valve HF2 automatically closed under the combined action of the second manifold valve spring, the self-weight of the second manifold valve disc, and the remaining medium pressure in the pilot control circuit of the upper chamber of the main valve MF piston. As a result, the pressure in the pilot control circuit of the upper chamber of the main valve MF piston gradually increased to the medium pressure, achieving a balance between the pressures in the upper and lower chambers of the piston. The main valve MF closed under the combined action of the main valve spring and the self-weight of the main valve disc assembly.The second safety manifold valve AH2 is also equipped with a second test interface SY2, which allows for independent testing of the second spring-piloted control circuit TX2 by connecting an external pressure source after isolation by the second manual isolation valve GL2. Additionally, the second safety valve AF2 has an overall pressure regulation function, allowing the set pressure to be adjusted within a preset range as needed.

[0060] The electromagnetic pilot control loop DX3 consists of an electromagnetic pilot valve DF containing two solenoid valves connected in series. These are directly connected to the main valve pilot control port in the upper chamber of the main valve MF piston, and secured to the main valve MF body with bolts, nuts, and anti-loosening washers. This forms a manual and automatic remote control loop for controlling the operation of the main valve MF. Normally, the two series-connected solenoid valves are de-energized and closed, isolating the pilot passage in the upper chamber of the main valve MF piston. The main valve MF is closed under the combined action of the main valve spring and the weight of the main valve disc assembly. When manual or automatic remote control via a detection and control system is required to open the main valve through the electromagnetic pilot control loop DX3, both series-connected solenoid valves in the electromagnetic pilot valve DF are simultaneously energized. Both valves open simultaneously, connecting the two passages of the electromagnetic pilot valve DF. This connects the entire electromagnetic pilot control loop DX3 to the main valve pilot control port in the upper chamber of the main valve MF piston, releasing the medium pressure in the upper chamber of the main valve MF piston and thus controlling the opening of the main valve MF. The two series-connected solenoid valves provide redundancy and improved reliability. On the one hand, this improves the reliability of preventing accidental opening. If one solenoid valve is accidentally energized, it will not open the entire solenoid pilot control circuit DX3, preventing a serious accident like the main valve MF being opened. Only by simultaneously energizing both solenoid valves connected in series can the entire solenoid pilot control circuit DX3 be opened, thus controlling the main valve MF to open correctly. On the other hand, it improves the reliability of the solenoid pilot control circuit DX3 controlling the main valve MF to close. To prevent abnormal situations such as solenoid valve jamming, when the main valve needs to be closed by the solenoid pilot valve DF, both solenoid valves connected in series are de-energized during normal closing. As long as one solenoid valve is normally de-energized and closed properly, the entire solenoid pilot control circuit DX3 is isolated, thereby controlling the main valve MF to close and improving the reliability of ensuring the main valve MF is closed. Furthermore, the two solenoid valves of the solenoid pilot valve DF are equipped with a first solenoid valve switch KG31 and a second solenoid valve switch KG32, which can provide signal feedback on the on / off status of the solenoid valves, facilitating accurate judgment of the valve status and improving control reliability.

[0061] The manual pilot control loop SX4 serves as the third control mode (purely manual control). It consists of a manual isolation valve GL4 directly connected to the main valve pilot control port in the upper chamber of the main valve MF piston. This connection is secured to the main valve MF body with bolts, nuts, and anti-loosening washers, forming a purely manual control loop for controlling the operation of the main valve MF. Under normal conditions, the manual isolation valve GL4 is closed. When dual-redundant automatic control, manual control, and automatic remote control all fail to open the main valve, the manual isolation valve GL4 can be opened manually via the SX4 pilot control loop. This opens the main valve pilot control port in the upper chamber of the main valve MF piston, releasing the medium pressure and thus controlling the opening of the main valve MF, thereby improving the reliability of the main valve opening. When the manual isolation valve GL4 is closed, the manual pilot control loop SX4 is isolated, thus closing the main valve MF.

[0062] The first manual isolation valve GL1, the second manual isolation valve GL2, and the manual circuit manual isolation valve GL4 all adopt an extended valve cover design suitable for high-temperature operating conditions. They utilize a drive control method with a small, compact valve lock, effectively locking the valve position. The valves can only be operated manually by opening the lock, thus preventing accidental operation and improving the reliability against accidental opening of the main valve. Simultaneously, the drive control method with a small, compact valve lock reduces the weight of the manual isolation extension, improving the overall shock resistance of the isolation valves.

[0063] This invention relates to a compact, easy-to-assemble and disassemble, pressure tapping and control integrated, adjustable set pressure, signal feedback, and highly reliable pilot-operated safety valve with multiple redundant control functions (dual-redundant automatic control, manual and automatic remote control, and purely manual control). Specifically, it is applied in advanced third-generation "Hualong One" pressurized water reactor nuclear power plants, installed on top of the pressurizer to perform hot overpressure protection, cold overpressure protection, charging and discharging functions, and manual pressure relief after an accident. The valve features a compact structure, signal feedback, multiple redundant control functions (dual-redundant automatic control, manual and automatic remote control, and purely manual control), high reliability, and high seismic resistance, belonging to the field of safety valves. It can also be extended to similar safety valve applications in nuclear power and thermal power plants with safety and control function requirements.

[0064] In this embodiment, the installation layout diagram of the main valve MF, two spring-operated control circuits TX1 and TX2, one electromagnetic pilot control circuit DX3, and one manual pilot control circuit SX4 is shown in the attached diagram. Figure 2-6 .

[0065] This embodiment mainly discloses and protects a control method for a safety valve. The specific structure is not within the protection scope of this embodiment. The main valve and safety manifold valve in this embodiment can adopt conventional structures that are compatible with this control principle.

[0066] Example 2 The technical solution of Example 2 is basically the same as that of Example 1, except that this example provides a pilot-operated main valve that can be applied to Example 1, as follows: like Figure 7-21 The main valve shown includes: a main valve body 1, which internally forms a medium inlet flow channel, a main valve cavity, and a medium outlet flow channel, all three being interconnected; the upper end of the main valve body 1 is connected to the main valve cover 2 via a bolt assembly, and a main valve bracket 3 is mounted on the upper end of the main valve cover 2 via a bolt assembly, the main valve bracket 3 being equipped with a valve opening / closing position and opening degree detection mechanism; a valve seat 4 is welded onto the main valve body 1, and a main valve disc assembly is disposed in the main valve cavity above the valve seat 4; a valve disc connector 5 is disposed on the upper end of the main valve disc assembly, and a main valve spring mechanism is mounted on the upper end of the valve disc connector 5; a main valve stem 6 is connected to the valve disc connector 5; the main valve stem 6... The top end passes through the main valve spring mechanism and extends out of the upper end of the main valve cover 2 to the position of the main valve bracket 3; a temperature detection device is installed on the main valve body 1 located in the medium inlet flow channel; the outer surface of the main valve body 1 corresponding to the temperature detection device is the outer inclined surface 101 of the main valve body, the two planes adjacent to the outer inclined surface 101 of the main valve body are the front 102 and rear 103 of the main valve body, and the plane opposite to the outer inclined surface 101 of the main valve body is the side 104 of the main valve body; the front 102 and rear 103 of the main valve body are respectively provided with main valve pressure tapping holes, and the front 102, rear 103 and side 104 of the main valve body 1 are provided with main valve pilot control holes; Based on the above scheme, the main valve body 1 of the main valve is equipped with a main valve pressure tapping port and a main valve pilot control port, which can realize dual redundant automatic control, manual and automatic remote control, and pure manual control. Furthermore, the main valve pressure tap and main valve pilot control port arranged in front 102 and rear 103 of the main valve body 1 as a dual redundant automatic control circuit are symmetrical mirror structure, which facilitates the balance of the weight center of gravity of the whole machine and improves the seismic performance.

[0067] Specifically, the front 102 and rear 103 of the main valve body 1 are provided with a first main valve pressure tap 7 and a second main valve pressure tap 8; the front 102 and rear 103 of the main valve body 1 are provided with a first pilot hole 9 and a second pilot hole 10, and the side 104 is provided with a third pilot hole 11 and a fourth pilot hole 12. Furthermore, positioning pin holes 105 and fastening threaded holes 106 are arranged near the main valve pressure taps on the front 102 and rear 103 of the main valve body 1, and near the main valve pilot control holes on the front 102, rear 103 and side 104 of the main valve body 1. All the complete set of control accessories can be fastened to the main valve body 1 by bolt assemblies (bolts, nuts and anti-loosening washers), so as to achieve the characteristics of compact structure and easy disassembly and assembly of the whole machine.

[0068] Furthermore, the main valve body 1 adopts an integral forging structure with the inlet medium flow channel and the outlet medium flow channel forming a 45° angle; this facilitates the overall layout of the pressure regulator dome structure on site, saving the overall space layout of the pilot-operated pressure regulator safety valve, and also making the overall system structure compact and with high space utilization.

[0069] Furthermore, the main valve body's medium outlet flow channel has a gradually enlarging structure, a design feature tailored to the valve's ability to increase volume and flow rate after steam discharge.

[0070] Furthermore, the main valve body 1 is provided with an inlet flange 13 and an outlet flange 14 at its inlet and outlet, respectively. The inlet flange 13, which is opposite to the inlet of the main valve body 1, is connected to the main valve body 1 by butt welding to form the main body of the main valve body 1. The inlet flange 13 is connected to the inlet mating flange 15 by a bolt assembly. The outlet of the main valve body 1 is connected to the outlet flange 14 by a bolt assembly, which facilitates the disassembly and installation of the valve.

[0071] Furthermore, a main valve spiral wound gasket is provided between the inlet flange 13 and the inlet mating flange 15, and between the main valve body 1 and the outlet flange 14, to ensure the sealing performance of the flange connection. Specifically, grooves for accommodating sealing gaskets are provided on the end faces of the inlet mating flange 15 and the outlet flange 14. A first main valve spiral wound gasket 16 is installed in the groove of the inlet mating flange 15, and a second main valve spiral wound gasket 17 is installed in the groove of the outlet flange 14. The first main valve spiral wound gasket 16, the inlet mating flange 15, and the bolt assembly are connected to the inlet flange 13, and the second main valve spiral wound gasket 17, the outlet flange 14, and the bolt assembly are connected to the outlet of the main valve body 1.

[0072] Furthermore, a main valve spiral wound gasket is installed at the junction of the upper end of the main valve body 1 and the main valve cover 2. A groove is formed on the upper surface of the main valve body 1 to accommodate a third main valve spiral wound gasket 18. The third main valve spiral wound gasket 18 is pressed into the sealing groove on the upper surface of the main valve body 1 by the main valve cover 2 using a bolt assembly. This ensures sealing performance under different pressure changes (low and high pressure) and different temperature expansion changes, with the sealing performance improving as the pressure increases. This sealing structure, where the main valve spiral wound gasket is installed in the groove, facilitates installation and fixed positioning, and prevents damage due to excessive pressure or disassembly of valve parts. It can also be reused multiple times, reducing costs. Simultaneously, this sealing structure prevents impurities from being introduced into the valve cavity and pipeline when replacing the main valve spiral wound gasket or disassembling the valve, thus preventing foreign objects from entering the pipeline. Furthermore, the sealing principle and effect of the first main valve spiral wound gasket 16 and the second main valve spiral wound gasket 17 in this solution are the same as those of the third main valve spiral wound gasket 18.

[0073] Furthermore, the main valve disc assembly includes: a main valve disc 19, a main valve piston cylinder 20, a stainless steel wear-resistant steel ring, an anti-loosening gasket 21, and an internal hexagonal head screw 22; the lower part of the main valve disc 19 is a large end, and the top part is a small end connected to the valve disc connector 5. The outer diameter of the large end of the main valve disc 19 mates with the main valve piston cylinder 20, and the outer diameter of the main valve piston cylinder 20 mates with the inner wall of the main valve body 1; the upper end face of the main valve piston cylinder 20 is connected to the main valve cover 2 by a bolt assembly, and the center of the main valve cover 2 has a receiving cavity for accommodating the main valve disc 19, the valve disc connector 5, and the main valve spring mechanism above it; a medium flow channel is provided in the middle of the main valve disc 19, which includes a radially bent channel that passes through the lower part and the upper surface of the large end of the main valve disc, and an axial channel that passes through both horizontal ends of the large end of the main valve disc, thereby achieving a medium balance effect through the axial channel; The lower section of the radially bent channel is equipped with an internal hexagonal head screw 22. The internal hexagonal head screw 22 is set in the lower section through an anti-loosening washer 21, and the center of the internal hexagonal head screw 22 has a throttling orifice 191 for controlling the flow rate of the medium. The opening and closing time of the valve can be adjusted by controlling the size of the throttling orifice 191.

[0074] Based on the above scheme, the main valve disc 19 integrates the functions of a normal valve disc and a piston, and the lower base part (large end) of the main valve disc 19 serves as the functional part of the normal valve disc. Furthermore, wear-resistant parts are respectively provided between the outer diameter of the large end of the main valve disc 19 and the inner diameter of the main valve piston cylinder 20, and between the small end of the main valve disc 19 and the inner diameter of the valve stem guide sleeve 23, which are applicable to the auxiliary support and guiding movement of the piston function; including a first stainless steel wear-resistant steel ring 24 and a second stainless steel wear-resistant steel ring 25, and both stainless steel wear-resistant steel rings are installed in the groove opened on the main valve disc 19. Furthermore, a wear-resistant component, namely a third stainless steel wear-resistant ring 26, is also provided between the outer diameter of the main valve piston cylinder 20 and the inner wall of the main valve body 1. The third stainless steel wear-resistant ring 26 is installed in a groove opened on the outer diameter of the main valve piston cylinder 20. The third stainless steel wear-resistant ring 26 is installed in the groove of the main valve piston cylinder 20 and fastened to the main valve cover 2 by bolt assembly. It can be removed from the main valve body 1 along with the main valve cover 2 as a whole.

[0075] With the above design, the valve can be removed entirely from the valve by disassembling only the bolt assembly (studs, nuts, and anti-loosening washers) in the middle cavity, which facilitates the disassembly, maintenance, and inspection of the valve.

[0076] Based on the wear-resistant component set between the outer diameter of the large end of the main valve disc 19 and the inner diameter of the main valve piston cylinder 20, the first stainless steel wear-resistant steel ring 24 is set in two lines on the outer diameter surface of the large end of the main valve disc 19.

[0077] Furthermore, the valve stem guide sleeve 23 is made of wear-resistant material and is screwed into the main valve cover 2 by threads to assemble and cooperate with the main valve cover 2; the valve stem guide sleeve 23 and the main valve piston cylinder 20 together play a role in positioning the main valve disc 19 and guiding its reciprocating motion.

[0078] Furthermore, the valve seat 4 is welded to the main valve body 1 according to a water seal structure layout to ensure the valve's sealing requirements; and the valve seat 4 is set in a gradually enlarging structure to meet the characteristics of the fluid medium in steam discharge; the valve seat 4 is welded to the main valve body 1, and if the medium has a large impact force on the valve seat, the valve seat 4 can be cut from the welded joint of the main valve body 1, replaced or repaired, and then reinstalled and welded back to normal operating condition.

[0079] Furthermore, a sealing contact surface is formed between the upper end of the valve seat 4 and the lower part of the main valve disc 19. The sealing contact surface between the two is treated with hard alloy overlay welding to improve the impact resistance, media erosion resistance and wear resistance of the sealing surface.

[0080] Furthermore, the main valve spring mechanism includes: a main valve spring seat 27 disposed on the valve disc connector 5 and a main valve spring 28 located on the main valve spring seat 27; the main valve spring seat 27 is connected to the main valve disc 19 through the valve disc connector 5, so that the main valve spring seat 27 can move up and down and reciprocate with the main valve disc 19; one end of the main valve spring 28 contacts and is positioned with the main valve spring seat 27, and the other end contacts and is positioned with the main valve cover 2; the main valve spring 28 serves as an auxiliary force for the closing of the main valve disc 19, so that the main valve disc 19 and other related components tend to close automatically under their own gravity.

[0081] Furthermore, the main valve stem 6 is installed between the valve disc connector 5 and the main valve spring seat 27, and moves up and down with the main valve disc 19, and leads the opening and closing position of the main valve disc 19 to the outside of the valve, and the valve opening and closing position and opening degree are detected and signaled by the valve opening and closing position and opening degree detection mechanism. Furthermore, a main valve packing sealing assembly is provided between the main valve stem 6 and the main valve cover 2. The main valve packing sealing assembly includes a main valve packing pressure plate 29, a main valve packing pressure sleeve 30, main valve packing 31, and a main valve packing pad 32. The main valve packing pressure plate 29 is located on the main valve stem 6 above the main valve cover 2. A main valve packing cavity is provided between the main valve stem 6 and the main valve cover 2 below the main valve packing pressure plate 29. The main valve packing 31 is pressed into the main valve packing cavity by the main valve packing pressure sleeve 30, and the main valve packing pad 32 is provided at the bottom of the main valve packing cavity. The setting of this main valve packing sealing assembly ensures the sealing reliability between the main valve cover 2 and the main valve stem 6, and also ensures the sealing reliability of the main valve stem 6 during reciprocating motion under temperature and pressure changes. Furthermore, the main valve packing sealing assembly is fastened above by a fastening assembly 33, which is composed of a stud, a disc spring indicator needle, a disc spring indicator plate, a disc spring sleeve, a disc spring, a gasket, and a nut. This ensures the sealing reliability of the main valve packing at the main valve stem 6 under temperature and pressure changes and enables visual control of the fastening force.

[0082] Furthermore, the valve switch position and opening degree detection mechanism includes: a valve position indicator 34, an indicator rod 35, and a limit switch 36; the indicator rod 35 is fixed to the upper end of the main valve stem 6 by a nut 37 and an anti-loosening washer, the main body of the valve position indicator 34 is fixed to the main valve bracket 3, the magnetic head is fixed to the indicator rod 35, and the limit switch 36 is fixed to the main valve bracket 3 by an internal hexagonal head screw a38 and a limit switch seat.

[0083] The valve position indicator 34 is a magnetostrictive non-contact valve position indicator, which realizes the detection and signal feedback of the valve opening and closing position; the limit switch 36 is an open and closed mechanical limit switch, which realizes the detection and signal feedback of the valve opening and closing position.

[0084] Furthermore, the temperature detection device is an embedded non-penetrating temperature sensor 39, which realizes the detection and signal feedback of the medium temperature at the inlet of valve 1, and reduces external leakage points.

[0085] It should be noted that the bolt assemblies mentioned in this article all adopt a combination structure of studs, nuts, and lock washers.

[0086] In the above structure, the front 102, rear 103, and side 104 of the main valve body are connected through four pilot holes to form the pilot circuit of the safety valve. The pilot circuit is connected to the upper chamber area of ​​the main valve piston cylinder in the main valve body 1. The main valve adopts a pilot-operated self-driven structure with a built-in main valve piston cylinder. The change in the pressure of the medium inside the main valve and the pilot circuit pressure in the upper chamber of the main valve piston cylinder creates a change in the force on the piston, thereby realizing the opening and closing of the main valve. In the main valve body 1, the upper part of the large end of the main valve disc 19, together with the inner wall of the main valve piston cylinder 20 and the lower end face of the main valve cover 2, forms a cavity gap 40. When the pressure difference between the medium pressure entering the main valve inlet and the medium pressure in the pilot circuit of the upper chamber of the piston changes, the main valve disc assembly is forced to reciprocate up and down. When the pressure inside the main valve body 1 is greater than the pressure in the pilot circuit, the main valve disc assembly moves upward, causing the cavity gap 40 located at the upper part of the large end of the main valve disc 19 to gradually disappear, thereby causing the lower end of the main valve disc 19 to separate from the valve seat 4 and form a gap, thus opening the valve. Conversely, when the pressure in the pilot circuit is close to or equal to the medium pressure of the main valve body 1, the main valve disc assembly moves downward, causing the lower end of the main valve disc 19 to move closer to the valve seat 4, causing the cavity gap 40 located at the upper part of the large end of the main valve disc 19 to gradually recover, thus closing the valve.

[0087] Example 3 The technical solution of Embodiment 3 is basically the same as that of Embodiments 1 and 2, except that this embodiment provides a safety manifold valve that can be applied to Embodiments 1 and 2, as detailed below: See Figure 22 and Figure 23 The safety manifold valve is composed of a safety valve and a manifold valve integrated into a single unit. Figure 22 The left side is the safety valve section, and the right side is the manifold valve section. The left and right sides share the safety manifold valve body 100. It is connected to the main valve of the pilot-operated safety valve only through the safety valve pressure tap 111 and the pilot control port 131 of the manifold valve. Together, they can realize the acquisition of the inlet pressure of the main valve of the pilot-operated safety valve and the pilot opening and closing control function of the main valve of the pilot-operated safety valve under the safety set pressure.

[0088] Specifically, see Figure 22The diagram shows the structure of a safety manifold valve, including a safety manifold valve body 100, a safety valve cover 200, a safety valve stem 300, a manifold valve cover 400, a manifold valve disc 500, and a manifold valve piston rod 600.

[0089] The safety manifold valve body 100 has an opening located at Figure 22 The safety valve chamber 110 on the left side, and located in Figure 22 The lower chamber 120 and upper chamber 130 of the manifold valve are located on the right side. The safety valve pressure tap 111 is connected to the safety valve chamber 110, and the upper chamber 130 is connected to the pilot control port 131. A manifold valve piston cylinder 121 is installed inside the lower chamber 120, and the safety valve chamber 110 is connected to the inner cavity of the manifold valve piston cylinder 121. The safety valve cover 200 is installed on the safety manifold valve body 100. The safety valve stem 300 passes through the safety valve cover 200, extends into the safety valve chamber 110, and can be positioned relative to the safety valve body 100. The full valve cover 200 is displaced axially along the safety valve stem 300; the manifold valve cover 400 is installed on the safety manifold valve body 100; the manifold valve disc 500 is located in the upper cavity 130 of the manifold valve, and a manifold valve spring 410 is arranged between the manifold valve disc 500 and the manifold valve cover 400; one end of the manifold valve piston rod 600 abuts against the manifold valve disc 500, and the other end cooperates with the outlet 123 of the manifold valve piston cylinder 121, and the manifold valve piston rod 600 is provided with a piston part 610 located inside the manifold valve piston cylinder 121.

[0090] The aforementioned pilot-operated safety valve uses the safety valve pressure tap 111 in the safety manifold to collect the inlet pressure of the main valve of the pilot-operated safety valve. When the pressure rises to the set discharge pressure of the safety valve, the safety valve stem 300 opens, and the pressure from the safety valve cavity 110 enters the inner cavity of the manifold piston cylinder 121, discharging pressure downstream to the manifold valve. As the pressure of the medium discharged from the safety valve to the manifold valve increases, the manifold piston rod 600 moves vertically upward under the action of the medium pressure, thereby pushing the manifold valve disc 500 upward until the force is sufficient to overcome the downward force of the pilot circuit medium on the manifold valve disc 500 and the downward pressure of the manifold valve spring 410, thus opening the manifold valve disc 500. In this way, the pilot circuit medium enters the upper cavity 130 of the manifold valve through the pilot control port 131, and flows together with the medium discharged from the safety valve through the manifold piston cylinder 121 to the outlet 123 of the manifold valve for discharge. This releases pressure on the pilot control circuit of the pilot-operated safety valve main valve, ultimately opening the pilot-operated safety valve main valve. When the safety valve reseats and closes, the pressure inside the manifold piston cylinder 121 decreases. The manifold piston rod 600 and the manifold valve disc 500 then move downwards under their own weight, the downward pressure of the manifold spring 410, and the force of the medium in the pilot control circuit of the pilot-operated safety valve main valve, until the manifold valve disc 500 returns to the sealing surface of the safety manifold valve body 100, forming a seal and ultimately closing the sealing pilot control circuit, thus closing the pilot-operated safety valve main valve to its designated position.

[0091] It should be noted that the safety manifold valve body 100 is the main component of the safety manifold valve, integrating the safety valve and the manifold valve into a single unit. It communicates with the main valve of the pilot-operated safety valve (not shown in the figure) through the safety valve pressure tap 111 and the manifold valve pilot control port 131. For specific settings, please refer to [reference needed]. Figure 7 The safety manifold valve body 100 of the pilot-operated safety valve has a first pin hole 150 and a second pin hole 160 pre-machined on it to facilitate installation and positioning with the pilot-operated safety valve body via mounting pins. The safety manifold valve body 100 also has a first bolt through hole 170 and a second bolt through hole 180 machined on it, allowing for easy installation and fixation of the entire safety manifold valve using only bolts, nuts, and anti-loosening washers, and facilitating subsequent disassembly and assembly.

[0092] See also Figure 22 The safety valve cavity 110 is connected to a first test pressure port 112, and the first test pressure port 112 is provided with a first safety valve blind flange 113 that is detachably connected to the safety manifold valve body 100; the safety valve pressure tap 111 is connected to a second test pressure port 114, and the second test pressure port 114 is provided with a second safety valve blind flange 115 that is detachably connected to the safety manifold valve body 100.

[0093] It should be noted that the safety manifold valve has a second safety valve blind flange 115 on its side. This second safety valve blind flange 115 can serve as a pressure tapping flange. When it is necessary to test the safety valve pressure, the flange 115 can be replaced with a flange featuring a safety valve pressure tap 111 to detect pressure changes before and after the safety valve. Additionally, after manually isolating the safety valve inlet with a pre-operated isolating valve, a separate external pressure source can be connected to the second safety valve blind flange 115 to test the set pressure and operational performance of the spring-piloted control circuit.

[0094] See Figure 25 A first spiral wound gasket 116 is provided between the first safety valve blind flange 113 and the safety manifold valve body 100; a second spiral wound gasket 117 is provided between the second safety valve blind flange 115 and the safety manifold valve body 100. The first spiral wound gasket 116 is pressed into the sealing groove of the safety manifold valve body 100 by the first safety valve blind flange 113 using studs, anti-loosening gaskets, and nuts, ensuring sealing performance under different pressure changes and different temperature expansion changes, with better sealing performance as the pressure increases. The second spiral wound gasket 117 is pressed into the sealing groove of the safety manifold valve body 100 by the second safety valve blind flange 115 using studs, anti-loosening gaskets, and nuts, ensuring sealing performance under different pressure changes and different temperature expansion changes, with better sealing performance as the pressure increases.

[0095] See also Figure 23 and Figure 25 The safety valve adjusting sleeve 310 is threaded onto the safety valve adjusting nut 320, which is then screwed onto the safety valve cover 200. The safety valve adjusting nut 320 has a circumferentially distributed set of straight teeth. Using an external tool, the safety valve adjusting nut 320 can be rotated and adjusted, causing the safety valve adjusting sleeve 310 to move up and down relative to the safety valve cover 200, ultimately controlling the gap between the safety valve adjusting sleeve 310 and the valve body 100. After adjustment, the safety valve adjusting bolt 330 is screwed in. The safety valve adjusting bolt 330 engages with the straight teeth on the outer side of the locking safety valve adjusting nut 320, locking the position of the safety valve adjusting nut 320. This controls the pressure at which the safety valve starts discharging and the pressure changes of the medium flowing to the manifold valve after discharge. The fourth spiral wound gasket 340 is screwed and pressed into the sealing groove of the safety manifold valve body 100 by the safety valve adjusting bolt 330, ensuring the required sealing performance.

[0096] See also Figure 25As the main moving part of the safety valve, the safety valve stem 300 has hard alloy 370 welded onto its sealing contact surface with the safety manifold valve body 100. Both surfaces are machined with a throttling control fit to ensure normal sealing and discharge performance of the safety valve. The hard alloy welded onto the sealing surface improves its impact resistance, resistance to media erosion, and wear resistance. The safety valve positioning nut 350 is screwed onto the safety valve stem 300. Adjusting the screwing height of the safety valve positioning nut 350 on the safety valve stem 300 controls the distance between the safety valve positioning nut 350 and the safety valve cover 200, thereby controlling the opening height of the safety valve discharge operation.

[0097] The safety valve spring 360 is compressed between the upper safety valve spring seat 361 and the lower safety valve spring seat 362, pushing the safety valve stem 300 towards a closed state. After the safety valve releases pressure, as the medium pressure before the safety valve decreases, the safety valve stem 300 will automatically descend until it closes to the sealing surface of the safety manifold valve body 100, thus achieving the closure and sealing of the safety valve.

[0098] like Figure 26 As shown, the fifth spiral wound gasket 140 is pressed into the sealing ring groove of the safety manifold valve body 100 by the safety valve cover 200 through studs, anti-loosening gaskets, and nuts, ensuring the sealing performance of the connection between the safety valve cover 200 and the safety manifold valve body 100 under different pressure changes and different temperature expansion changes, and the sealing performance is better as the pressure increases.

[0099] See also Figure 22 and Figure 25 As described above, a safety valve sealing assembly 210 is provided between the safety valve stem 300 and the safety valve cover 200. The safety valve sealing assembly 210 includes a safety valve packing gasket 211 and a safety valve packing 212 stacked from bottom to top. A safety valve packing pressure plate 213, which is detachably connected to the safety valve cover 200, is stacked on top of the safety valve packing 212. In this embodiment, the safety valve packing gasket 211 and the safety valve packing 212 are installed between the safety valve stem 300 and the safety valve cover 200, and are fastened to the safety valve cover 200 by the safety valve packing pressure plate 213 through studs, anti-loosening washers, and nuts, ensuring the sealing performance between the safety valve stem 300 and the safety valve cover 200 under different pressure changes and different temperature expansion changes.

[0100] like Figure 22As shown, the safety valve spring sleeve 220 is welded to the safety valve cover 200, serving two purposes: protecting and positioning the safety valve spring 360, and providing support and connection. The safety valve adjusting screw 221 is screwed onto the safety valve spring sleeve 220, with its lower part in positioning and pressing contact with the upper safety valve spring seat 361. By adjusting the height of the safety valve adjusting screw 221, the pressing force on the safety valve spring 360 is adjusted, ultimately achieving the adjustment of the set discharge pressure of the safety valve. After the set discharge pressure is set, it can be locked and positioned by the safety valve locking nut 223 to ensure that the set discharge pressure does not change. The upper part of the safety valve spring sleeve 220 is screwed and fixed with a safety valve limit switch seat 222, serving as the basic support for the safety valve switch position signal feedback.

[0101] Furthermore, in conjunction with see Figure 27 A switch assembly 700, including a micro switch 710, is mounted on the upper part of the safety valve limit switch base 222. The micro switch 700 has two positions: an open position switch and a closed position switch. These are clamped together by bolts, flat washers, and nuts via a first safety valve limit switch bracket 711 and a second safety valve limit switch bracket 712. The open and closed positions can be adjusted according to the height and stroke of the safety valve stem 300. The entire assembly is then fixed to the safety valve limit switch cover 720 by hexagonal head screws and anti-loosening washers. The micro switch 710 is wired to the safety valve electrical connector 730. The safety valve electrical connector 730 is a quick-plug sealed structure, facilitating rapid disassembly or installation of the connection wiring. This allows for quick plug-and-play connections to external interfaces while ensuring the connector meets requirements for sealing, insulation, shock resistance, and electromagnetic interference resistance. Similarly, the safety valve electrical connector 730 is fixed to the safety valve limit switch cover 720 by hexagonal head screws and anti-loosening washers. The safety valve limit switch cover 720 is fixed to the safety valve limit switch seat 222 by internal hexagonal head screws and anti-loosening washers.

[0102] The safety valve section of the aforementioned pilot-operated safety valve manifold is equipped with an open switch and a closed switch, which can provide signal feedback on the open / closed position of the safety valve, thereby verifying the conduction and closure status of the main valve control circuit, facilitating subsequent judgment of the opening and closing status of the pilot-operated safety valve main valve.

[0103] See Figure 26The manifold piston cylinder 121 is a major internal component of the manifold valve, positioned within the manifold valve section of the safety manifold valve body 100 by the manifold blind flange 122. The manifold piston cylinder 121 has guide holes and guide spaces inside and around its periphery, allowing the media discharged from the safety valve and the pilot control circuit to be collected and discharged together at the manifold valve outlet 123. Simultaneously, the manifold blind flange 122 uses studs, anti-loosening gaskets, and nuts to press the sixth spiral wound gasket 124 into the sealing ring groove of the safety manifold valve body 100, ensuring the sealing performance of the connection between the safety manifold valve body 100 and the manifold blind flange 122 under different pressure and temperature expansion changes, with the sealing performance improving as the pressure increases.

[0104] See also Figure 26 The seventh spiral wound gasket 810 is pressed into the sealing ring groove of the safety manifold valve body 100 by studs, anti-loosening gaskets, and nuts from the manifold valve outlet flange 800. This ensures the sealing performance of the connection between the safety manifold valve body 100 and the manifold valve outlet flange 800 under different pressure changes and different temperature expansion changes, and the sealing performance is better as the pressure increases. The manifold valve outlet flange 800 also serves to position and press the manifold valve piston cylinder 121 into the inner cavity of the manifold valve part of the safety manifold valve body 100.

[0105] A third spiral wound gasket 420 is provided between the manifold cover 400 and the safety manifold body 100.

[0106] The manifold cover 400 uses studs, anti-loosening washers, and nuts to keep the manifold spring 410 in a compressed state, and at the same time presses the third spiral wound gasket 420 into the sealing ring groove of the safety manifold body 100, ensuring the sealing performance of the connection between the safety manifold body 100 and the manifold cover 400 under different pressure changes and different temperature expansion changes, and the sealing performance is better as the pressure increases.

[0107] In addition, the safety manifold valve has a first safety valve blind flange 113 on its side, which can be used as a pressure tapping interface flange. When it is necessary to test the safety valve pressure, the flange can be replaced with a flange with a pressure tapping hole to detect the pressure changes before and after the safety valve. Furthermore, after manually isolating the safety valve inlet with a pre-operated isolating valve, a separate external pressure source can be connected to the sealing flange to test the set pressure and operational performance of the spring-operated control circuit. The safety manifold valve body 100 has a first pin hole 150 and a second pin hole 160 pre-machined on it to facilitate the installation and positioning of the pins with the pilot-operated safety valve body. The safety manifold valve body 100 also has a first bolt through hole 170 and a second bolt through hole 180 pre-machined on it. Through these bolt through holes, bolts, nuts, and anti-loosening washers can be used to install and fix the entire safety manifold valve, facilitating subsequent disassembly and assembly.

[0108] When the aforementioned pilot-operated safety valve operates with a safety manifold valve, if the inlet pressure of the main valve of the pilot-operated safety valve rises to the set discharge pressure of the safety valve, the valve stem 300 of the safety valve trips, and the safety valve automatically opens to discharge pressure to the downstream manifold valve. The set discharge pressure, opening height, and pressure control value of the discharge to the manifold valve can be controlled through an internal adjustment structure. The manifold valve piston rod 600 is installed inside the manifold valve piston cylinder 121. As the pressure of the medium discharged from the safety valve to the manifold valve increases, the manifold valve piston rod 600 moves vertically upward under the action of the medium pressure, thereby pushing the manifold valve disc 500 upward until the force is sufficient to overcome the downward force of the pilot circuit medium on the manifold valve disc 500 and the downward pressure of the manifold valve spring 410, thus opening the manifold valve disc 500. In this way, the pilot circuit medium flows through the manifold valve piston cylinder 121 and merges with the medium discharged from the safety valve to the outlet 123 of the manifold valve for discharge. This releases pressure on the pilot control circuit of the pilot-operated safety valve main valve, ultimately opening the pilot-operated safety valve main valve. When the safety valve reseats and closes, the pressure inside the manifold piston cylinder 121 decreases. The manifold piston rod 600 and the manifold valve disc 500 then move downwards under their own weight, the downward pressure of the manifold spring 410, and the force of the medium in the pilot control circuit of the pilot-operated safety valve main valve until the manifold valve disc 500 returns to the sealing surface of the safety manifold valve body 100, forming a seal and ultimately closing the sealed pilot control circuit, thus closing the pilot-operated safety valve main valve. Hard alloy material is welded onto both the manifold valve disc 500 and the sealing surface of the safety manifold valve body 100 to improve the sealing surface's impact resistance, resistance to media erosion, and wear resistance.

[0109] The safety valve features a compact structure, adjustable set pressure, adjustable opening height, and adjustable control force for the manifold valve opening. It also has a switch position signal feedback function. Hard alloy is welded to the sealing contact surfaces of the safety valve stem 300 and the safety manifold valve body 100 to improve wear resistance and resistance to media erosion. A throttling control fit shape is also machined to ensure normal sealing and discharge performance of the safety valve. The safety valve pressure tap 111 on one side collects the inlet pressure of the pilot-operated safety valve's main valve, and automatically opens for discharge and reseats to close based on pressure changes. The discharged media pressure flows directly into the inner cavity of the manifold valve piston cylinder 121, thus indirectly controlling the opening and closing of the manifold valve. When the inlet pressure of the pilot-operated safety valve's main valve rises to the set discharge pressure of the safety valve, the safety valve automatically opens, discharging pressure to the downstream manifold valve. The set discharge pressure, opening height, and pressure control value of the discharge to the manifold valve can be controlled by an internal adjustment structure.

[0110] The manifold valve is a multi-functional composite valve with a built-in manifold valve piston cylinder 121. The opening and closing of the manifold valve controls the opening and closing of the main valve control circuit, thereby controlling the opening and closing of the pilot-operated safety valve main valve. On one hand, the manifold valve releases the discharge pressure after the safety valve trips through its outlet 123; on the other hand, it utilizes the discharge pressure after the safety valve trips, through the driving force generated by the built-in manifold valve piston cylinder 121, to open the manifold valve disc 500 at the pilot control port 131. This releases the medium pressure in the pilot control circuit of the pilot-operated safety valve main valve piston upper chamber through the manifold valve outlet 123, thus allowing the main valve to open under the different medium pressures in the upper and lower chambers of the piston and remain in the open state. After the pressure before the main valve of the pilot-operated safety valve decreases to the reseating pressure value of the safety valve, the safety valve reseated and closed. The pressure after the safety valve is discharged and reduced through the outlet 123 of the manifold valve until the manifold valve automatically closes under the combined action of the manifold valve spring 410, the weight of the manifold valve disc 500, and the remaining medium pressure in the pilot control circuit of the main valve piston, thereby controlling the main valve of the pilot-operated safety valve to close.

[0111] The nameplate 900 is fixed to the side of the safety manifold valve body 100 by rivets 910, marking the valve's relevant parameters and other main information, and forming a complete whole with the entire safety manifold valve. The structure is compact, the spatial layout is reasonable, and the overall effect is harmonious and beautiful.

[0112] It should be noted that the parts of this invention not described in detail are prior art.

[0113] The above examples are merely preferred embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A pilot-operated safety valve, characterized in that: The system includes a main valve and a redundant multi-row spring-operated control circuit. The main valve is a self-driven pilot-operated valve with a built-in main valve piston cylinder. The multi-row spring-operated control circuits are all installed on the main valve body. Each spring-operated control circuit includes a manual isolation valve, a safety manifold valve, and a solenoid isolation valve. The safety manifold valve is an integrated unit combining a safety valve and a manifold valve. The manual isolation valve connects the main valve pressure tap in front of the main valve to the safety valve, achieving isolation and conduction control of the pressure path in front of the main valve. The solenoid isolation valve connects the main valve pilot control hole in the upper chamber of the main valve piston to the manifold valve pilot control hole of the manifold valve, achieving isolation and conduction control of the path between the upper chamber of the main valve piston and the pilot control hole of the manifold valve.

2. The pilot-operated safety valve according to claim 1, characterized in that: The electromagnetic isolation valve is normally open and closes when energized, thereby isolating the pilot control orifice of the main valve and controlling the closure of the main valve. The electromagnetic isolation valve is equipped with a switch to provide signal feedback on the on / off position of the electromagnetic isolation valve. The safety valve is equipped with open and closed limit switches to provide signal feedback on the on / off position of the safety valve.

3. The pilot-operated safety valve according to claim 1, characterized in that: The spring-pilot control circuit consists of two rows, which are symmetrically arranged. When the pressure before the main valve reaches the set pressure value of the safety valve, the safety valve opens, and pressure is conducted to the manifold valve until the opening pressure of the manifold valve is reached, putting the manifold valve in the open state. This allows the medium pressure in the pilot control circuit of the main valve piston's upper chamber to be discharged through the outlet of the manifold valve. The main valve opens under the different medium pressures in the upper and lower chambers of the piston and remains open. When the pressure before the main valve decreases to the reseating pressure value of the safety valve, the safety valve reseats and closes. The pressure after the safety valve is discharged through the outlet of the manifold valve until the manifold valve automatically closes under the combined action of the manifold valve spring, the weight of the manifold valve disc, and the remaining medium pressure in the pilot control circuit of the main valve piston's upper chamber. This causes the pilot control circuit pressure in the upper chamber of the main valve piston to gradually increase to the medium pressure, achieving pressure balance between the upper and lower chambers of the piston. The main valve then closes under the combined action of the main valve spring and the weight of the main valve disc assembly.

4. The pilot-operated safety valve according to claim 1, characterized in that: It also includes an electromagnetic pilot control circuit, which is installed on the main valve body. The electromagnetic pilot control circuit includes an electromagnetic pilot valve composed of two electromagnetic valves connected in series. The electromagnetic pilot valve is directly connected to the main valve pilot control port in the upper chamber of the main valve piston. The two electromagnetic valves are normally closed and open when energized. Each of the two electromagnetic valves is equipped with a solenoid valve switch to provide signal feedback on the opening and closing status of the solenoid valves.

5. The pilot-operated safety valve according to claim 1, characterized in that: It also includes a manual pilot control circuit, which is installed on the main valve body. The manual pilot control circuit includes a manual isolation valve, which is directly connected to the main valve pilot control port in the upper chamber of the main valve piston. The manual isolation valve is normally closed.

6. The pilot-operated safety valve according to any one of claims 1-5, characterized in that: The safety manifold valve includes The safety manifold valve body has a safety valve cavity, a lower manifold valve cavity, and an upper manifold valve cavity. The safety valve pressure tap is connected to the safety valve cavity. The upper manifold valve cavity is connected to the pilot control hole of the manifold valve. A manifold valve piston cylinder is installed in the lower manifold valve cavity. The safety valve cavity is connected to the inner cavity of the manifold valve piston cylinder. The safety valve cover is installed on the safety manifold valve body; The safety valve stem passes through the safety valve cover, extends into the safety valve cavity, and is capable of axial displacement relative to the safety valve cover along the safety valve stem. The manifold cover is installed on the safety manifold body; A manifold valve disc is located in the upper cavity of the manifold valve, and a manifold valve spring is disposed between the manifold valve disc and the manifold valve cover; The manifold valve piston rod has one end abutting against the manifold valve disc and the other end cooperating with the outlet of the manifold valve piston cylinder. The manifold valve piston rod is equipped with a piston portion disposed inside the manifold valve piston cylinder.

7. The pilot-operated safety valve according to claim 6, characterized in that: A safety valve spring sleeve is fixed to the upper part of the safety valve cover, and a safety valve adjusting screw is screwed onto the upper part of the safety valve spring sleeve; The safety valve stem is externally fitted with an upper safety valve spring seat and a lower safety valve spring seat. A safety valve spring is disposed between the upper safety valve spring seat and the lower safety valve spring seat. The upper safety valve spring seat abuts against the bottom of the safety valve adjusting screw, and the lower safety valve spring seat abuts against the safety valve stem. The safety valve spring sleeve is fixed with a safety valve limit switch seat. A switch assembly is provided on the upper part of the safety valve limit switch seat. The switch assembly includes a micro switch, which is used to adjust the open and closed positions according to the height and stroke of the safety valve stem. The micro switch is wired and connected to the safety valve electrical connector. The safety valve electrical connector is fixed to the safety valve limit switch cover. The safety valve limit switch cover is fixed to the safety valve limit switch seat. The safety valve electrical connector is a quick-plug sealed structure.

8. The pilot-operated safety valve according to claim 6, characterized in that: The safety valve cavity is connected to a first test pressure port, and the first test pressure port is provided with a first safety valve blind flange that is detachably connected to the safety manifold valve body. The pressure tap is connected to a second pressure test port, and the second pressure test port is provided with a second safety valve blind flange that is detachably connected to the valve body of the safety manifold valve. The lower part of the safety valve cover is screwed with a safety valve adjusting nut. The outer circumference of the safety valve adjusting nut has multiple straight teeth evenly distributed around its periphery. The safety valve adjusting bolt can rotate to adjust the safety valve adjusting nut. The safety valve adjusting nut is threadedly connected to a safety valve adjusting sleeve. Adjusting the safety valve adjusting bolt controls the gap between the safety valve adjusting sleeve and the safety manifold valve body.

9. The pilot-operated safety valve according to any one of claims 1-5, characterized in that: The main valve includes a main valve body, which internally forms a medium inlet channel, a main valve cavity, and a medium outlet channel, all of which are interconnected. The upper end of the main valve body is connected to the main valve cover via a bolt assembly. A main valve bracket is mounted on the upper end of the main valve cover via the same bolt assembly. The main valve bracket houses the valve's open / close position and opening degree detection mechanism. A valve seat is welded onto the main valve body. A main valve disc assembly is located in the main valve cavity above the valve seat. A disc connector is located on the upper end of the disc assembly, and a main valve spring mechanism is mounted on the upper end of the disc connector. The main valve stem is connected to... In the valve disc connector, the top of the main valve stem passes through the main valve spring mechanism and extends out of the upper end of the main valve cover to the position of the main valve support; a temperature detection device is installed on the main valve body located in the medium inlet flow channel; the outer surface of the main valve body corresponding to the temperature detection device is the outer inclined surface of the main valve body, the two planes adjacent to the outer inclined surface of the main valve body are the front and rear of the main valve body, and the plane opposite to the outer inclined surface of the main valve body is the side of the main valve body; the front and rear of the main valve body are respectively provided with main valve pressure tapping holes, and the front, rear and side of the main valve body are provided with main valve pilot control holes.

10. The pilot-operated safety valve according to claim 9, characterized in that: The main valve disc assembly includes: a main valve disc, a main valve piston cylinder, and a stainless steel wear-resistant steel ring; the lower part of the main valve disc is a large end, and the top part is a small end connected to the valve disc connector. The outer diameter of the large end of the main valve disc mates with the main valve piston cylinder, and the outer diameter of the main valve piston cylinder mates with the inner wall of the main valve body; the upper end face of the main valve piston cylinder is connected to the main valve cover by a bolt assembly, and the center of the main valve cover has a receiving cavity for accommodating the main valve disc, the valve disc connector, and the main valve spring mechanism above it; the small end of the main valve disc mates with the receiving cavity of the main valve cover through a valve stem guide sleeve; the main valve disc integrates the normal valve disc function and the piston function; the main valve disc has a medium guiding channel, which includes a radially bent channel penetrating the lower and upper surfaces of the large end of the main valve disc and an axial channel penetrating the horizontal ends of the large end of the main valve disc; The main valve spring mechanism includes: a main valve spring seat disposed on the valve disc connector and a main valve spring located on the main valve spring seat; the main valve spring seat is connected to the main valve disc through the valve disc connector, so that the main valve spring seat can move up and down and reciprocate with the main valve disc; one end of the main valve spring contacts and is positioned with the main valve spring seat, and the other end contacts and is positioned with the main valve cover. The main valve is equipped with a temperature sensor, a switch open position indicator, a switch closed position indicator, and a valve position indicator to provide signal feedback on the valve medium temperature and valve open / close position status.

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