High pressure stop valve and control method thereof

Abstract

The application provides a high-pressure stop valve and a control method thereof, and relates to the technical field of control valves. The high-pressure stop valve comprises a main valve assembly and a pilot valve assembly. The main valve assembly is provided with a main valve inlet, a main valve outlet and a main valve driving port. A main valve piston is in sealing cooperation with a main valve body through dynamic sealing, and drives a main valve stem and a sealing protrusion of the valve body to form a sealing pair to control the on-off state. The pilot valve assembly forms first, second and third chambers that are in communication or isolation with each other. The pilot valve stem is in communication with the main valve inlet and the main valve driving port at an open valve position to drive the main valve to open, and is cut off from the main valve inlet at a closed valve position to guide the medium in the main valve driving port to the main valve outlet to achieve closed pressure relief backflow. The pilot valve adopts a force balance structure, and the action is not affected by the axial force of the high-pressure medium. The valve realizes zero medium leakage, fast response and lightweight driving, and is suitable for aerospace propulsion, hydrogen energy storage and transportation, high-pressure chemical industry and other scenes.

Description

Technical Field

[0001] This application relates to the field of control valve technology, and more specifically, to a high-pressure shut-off valve and its control method. Background Technology

[0002] In high-pressure fluid control systems, gate valves are typically used to control the flow of media, and their basic function is to cut off or connect the flow of media. The structure of a gate valve usually includes a valve core, a valve seat, and an actuator. When opening and closing, the valve core needs to overcome the axial thrust of the media acting on the sealing surface, which results in a very high operating force. Therefore, gate valves require a high-power actuator to provide sufficient driving force during application.

[0003] To reduce operating force, existing technologies employ two main approaches. The first approach utilizes force amplification structures. For example, patent document CN119687205A describes a "self-coaxially adjustable ultra-high pressure shut-off valve needle structure." This structure applies low-pressure gas (0-0.5 MPa) via a large-diameter pneumatic piston, which in turn drives a small-diameter needle valve stem to press against the sealing surface. This design utilizes a metal wire seal to shut off high-pressure media. Its core principle is that the effective area of ​​the piston is much larger than the valve core sealing area, thus amplifying the driving force. While this design effectively amplifies the driving force, because it is a direct-acting drive, the valve needle is constantly subjected to the force of the medium throughout the entire movement. Therefore, the operating force is not fundamentally reduced. Furthermore, as the valve diameter increases, the required size of the booster piston also increases exponentially, resulting in a large and heavy system with long pneumatic / hydraulic filling times and slow response speeds, making it unsuitable for high-flow, rapid-opening and closing scenarios.

[0004] To address the aforementioned shortcomings, the second approach employs a self-driven fluid design. Taking patent document CN120701791A as an example, this solution introduces a "pilot-operated self-driven fluid relief valve." This design utilizes the pressure of the medium to drive the main valve piston, controlling the filling and releasing pressure of the main valve piston chamber via a pilot valve. By utilizing the energy of the high-pressure medium itself to drive the main valve, the demand for actuators is reduced, thus achieving valve weight reduction. However, this design requires the medium in the piston chamber to be discharged when the valve is closed. When the medium being processed is flammable and explosive fluids such as liquid oxygen, kerosene, or hydrogen, or toxic and highly polluting fluids, this discharge design poses significant safety and environmental risks, and also leads to the waste of expensive media.

[0005] In summary, current technologies have not yet solved the design of high-pressure shut-off cone valves that achieve lightweight design, rapid response, and closed-loop media circulation. Especially for applications in aerospace, chemical, and other fields requiring high flow rates, high safety, and compatibility with all media, an innovative structure is urgently needed. Summary of the Invention

[0006] The purpose of this application is to provide a high-pressure shut-off valve and its control method in order to address the shortcomings of the above-mentioned technology.

[0007] To achieve the above objectives, the technical solution adopted in this application is as follows: One aspect of this application provides a high-pressure shut-off valve, including a main valve assembly and a pilot valve assembly; The main valve assembly includes a main valve body, a main valve piston that is axially connected to the inner wall of the main valve body, and a main valve stem that is fixedly connected to the main valve piston. The main valve body is provided with a main valve inlet, a main valve outlet, and a main valve drive port that communicates with the pressure side of the main valve piston. The main valve piston drives the main valve stem to move so that the sealing end face of the main valve stem and the sealing protrusion in the main valve body form a sealing pair for controlling the opening and closing of the main valve inlet and the main valve outlet. The pilot valve assembly includes a pilot valve body and a pilot valve stem that is axially connected to the inner wall of the pilot valve body. A first annular protrusion and a second annular protrusion are axially spaced on the inner wall of the pilot valve body. A first boss, a second boss, and a third boss are axially spaced on the pilot valve stem. The first boss and the third boss are respectively sealed to the inner wall of the pilot valve body. The second boss is located between the first annular protrusion and the second annular protrusion. The first annular protrusion and the first boss form a first chamber. The first annular protrusion and the second annular protrusion form a second chamber. The second annular protrusion and the third boss form a third chamber. The pilot valve body has a pilot valve inlet, a piston communication port, a pilot valve outlet, and a pilot valve drive port that communicates with the pressure side of the pilot valve stem. The first chamber is connected to the main valve inlet through the pilot valve inlet, the second chamber is connected to the main valve drive port through the piston communication port, and the third chamber is connected to the main valve outlet through the pilot valve outlet. The pilot valve stem has a closed position and an open position. The pilot valve drive port is used to connect or disconnect with the control air source to drive the pilot valve stem to switch between the closed and open positions. In the open position, the bottom surface of the second boss seals against the second annular protrusion to isolate the third chamber and connect the first and second chambers. This allows the medium at the main valve inlet to sequentially enter the main valve drive port through the pilot valve inlet, the first chamber, and the second chamber to act on the main valve piston, thereby connecting the main valve inlet and the main valve outlet. In the closed position, the top surface of the second boss seals against the first annular protrusion to isolate the first chamber and connect the second and third chambers. This allows the medium at the main valve drive port to sequentially flow through the piston connection port, the second chamber, the third chamber, and the pilot valve outlet to the main valve outlet to achieve closed pressure relief, thereby disconnecting the main valve inlet and the main valve outlet.

[0008] Furthermore, the effective pressure-bearing area of ​​the main valve piston is greater than the sealing end face area of ​​the main valve stem, so that the driving force of the medium at the main valve drive port on the main valve piston in the opening direction is greater than the resistance experienced by the main valve stem in the closing direction.

[0009] Furthermore, the main valve assembly also includes a main valve reset component. One end of the main valve reset component is fixed to the main valve body, and the other end abuts against the main valve piston. The main valve reset component is used to drive the main valve stem to reset to the sealing end face of the main valve stem and seal against the sealing protrusion in the main valve body after the main valve is closed and depressurized.

[0010] Furthermore, the main valve assembly also includes a main valve piston cover, which is sealed to the periphery of the main valve drive port. A first through hole is provided on the main valve piston cover, and the main valve drive port is connected to the piston communication port through the first through hole.

[0011] Furthermore, the sealing diameter of the first boss is the same as the sealing diameter of the third boss, the top sealing diameter of the second boss, and the bottom sealing diameter of the second boss, so that the axial force of the medium on the pilot valve stem in the first chamber, the second chamber, and the third chamber is balanced.

[0012] Furthermore, the pilot valve assembly also includes a pilot valve piston and a pilot valve reset component. The pilot valve piston is axially connected to the inner wall of the pilot valve body, and the pilot valve stem is fixedly connected to the pilot valve piston. One end of the pilot valve reset component is fixed to the pilot valve body, and the other end of the pilot valve reset component abuts against the pilot valve piston. The pilot valve reset component is used to drive the pilot valve stem to reset to the closed position after the control gas is removed.

[0013] Furthermore, the pilot valve assembly also includes a pilot valve piston cover, which is sealed to the periphery of the pilot valve drive port. A second through hole is provided on the pilot valve piston cover, which communicates with the pilot valve drive port. Control gas enters the pilot valve drive port through the second through hole to drive the pilot valve stem.

[0014] Furthermore, a pressure tap is provided on the side wall of the main valve inlet, and the main valve inlet is connected to the pilot valve inlet via the pressure tap; A pressure relief port is provided on the side wall of the main valve outlet, and the main valve outlet is connected to the pilot valve outlet through the pressure relief port.

[0015] Furthermore, the sealing pair formed by the sealing end face of the main valve stem and the sealing protrusion in the main valve body is a metal wire sealing pair or a metal conical wire sealing pair. The top surface of the second boss and the first annular protrusion form a first annular sealing pair, and the bottom surface of the second boss and the second annular protrusion form a second annular sealing pair. The first annular sealing pair and the second annular sealing pair are metal wire sealing pairs or metal conical wire sealing pairs.

[0016] In another aspect of this application, a control method for a high-pressure shut-off valve is provided for controlling any of the above-mentioned high-pressure shut-off valves. During the valve opening control stage, control gas is introduced into the pilot valve drive port to drive the pilot valve stem to move in the valve opening direction. The bottom surface of the second boss seals against the second annular protrusion to isolate the third chamber and connect the first chamber and the second chamber. This allows the medium at the main valve inlet to enter the main valve drive port sequentially through the pilot valve inlet, the first chamber, and the second chamber to act on the main valve piston, thereby connecting the main valve inlet and the main valve outlet. During the valve closing control phase, the control gas at the pilot valve drive port is removed, and the pilot valve stem moves in the valve closing direction. The top surface of the second boss seals against the first annular protrusion to isolate the first chamber and connect the second and third chambers. This allows the medium at the main valve drive port to flow sequentially through the piston connection port, the second chamber, the third chamber, and the pilot valve outlet to the main valve outlet to achieve closed pressure relief, thereby disconnecting the main valve inlet and the main valve outlet.

[0017] The beneficial effects of this application include: This application provides a high-pressure shut-off valve and its control method. Through the coordinated design of balanced force area of ​​the pilot valve and closed pressure relief and backflow of the main valve piston chamber, both operability and media safety are improved without increasing the complexity of the actuator. During valve closing, the high-pressure medium in the main valve piston chamber enters the pilot valve through the piston connection port and is guided to the main valve outlet side pipeline. This achieves closed circulation of the pressure relief medium within the valve and downstream channels instead of external discharge, avoiding the risks of combustion and explosion of flammable media, loss of cold energy of cryogenic media, contamination of high-purity media, and leakage of toxic media from the source. This enables the valve to adapt to harsh operating conditions such as liquid oxygen, kerosene, high-pressure hydrogen, and nitrogen, and to meet the high cleanliness and high sealing requirements of aerospace propulsion, hydrogen energy storage and transportation, high-pressure chemical processes, and semiconductor manufacturing. Scenario Requirements: During the opening process, the main valve utilizes the area difference—where the effective pressure-bearing area of ​​the piston is greater than the sealing end face area of ​​the valve stem—to generate self-driving force. Once the pilot valve is activated, it can quickly push the main valve open using the medium pressure, achieving millisecond-level response without the need for an additional actuator. Furthermore, the modular arrangement of the main valve assembly and the pilot valve assembly reduces manufacturing, assembly, and maintenance costs. Simultaneously, the pilot valve, through a pressure-balanced layout with consistent sealing diameters, ensures that the axial forces of the medium on the pilot valve stem cancel each other out during the opening and closing stroke. The drive side only needs to overcome the spring force and sealing friction to complete the reversal. This allows for the control of large-diameter, ultra-high-pressure media with a smaller diameter pilot valve piston and lower control air pressure, significantly reducing operating force and promoting lightweighting of the drive mechanism.

[0018] In summary, while maintaining the advantages of pilot-operated shut-off valves in terms of lightweight and rapid response, this application achieves a synergistic improvement in safety, applicability, and energy efficiency through two key innovations: "pilot valve force balance + pressure relief and closed backflow". Attached Figure Description

[0019] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This application provides one of the structural schematic diagrams of the main valve assembly of a high-pressure shut-off valve. Figure 2 This is the second schematic diagram of the main valve assembly of a high-pressure shut-off valve provided in this application; Figure 3 One of the structural schematic diagrams of a pilot valve assembly for a high-pressure shut-off valve provided in this application; Figure 4 This is the second schematic diagram of the pilot valve assembly of a high-pressure shut-off valve provided in this application.

[0021] Icons: 101-Main valve body; 102-Inlet connector; 103-Main valve stem; 104-Main valve piston; 105-Main valve reset element; 106-Main valve piston cover; 107-Static seal structure; 108-Dynamic seal structure; 109-Main valve inlet; 110-Main valve outlet; 111-Main valve drive port; 112-Main valve piston chamber; 113-Main valve reset element chamber; 121-Pressure tap; 122-First through hole; 123-Pressure relief port; 201-Pilot valve body; 202-Pilot valve seat; 203-Pilot valve body Rod; 203a-First boss; 203b-Second boss; 203c-Third boss; 204-Pilot valve piston; 205-Pilot valve reset component; 206-Pilot valve piston cover; 207-First annular protrusion; 208-Second annular protrusion; 209-Second through hole; 210-Pilot valve drive port; 211-Pilot valve piston chamber; 212-Pilot valve reset component chamber; 213-First chamber; 214-Second chamber; 215-Third chamber; 221-Pilot valve inlet; 222-Piston communication port; 223-Pilot valve outlet. Detailed Implementation

[0022] One aspect of this application provides a high-pressure shut-off valve, suitable for reliable control of medium flow under high-pressure conditions. The valve employs a structure where a main valve assembly and a pilot valve assembly work in concert. The main valve assembly, as the shut-off actuator carrying the main flow path, directly establishes or cuts off the medium passage between the main valve inlet and outlet. The pilot valve assembly, as a pilot control mechanism, drives and depressurizes the main valve assembly by changing the pressure state on the pressurized side of the main valve piston. This allows the valve to complete opening and closing switching with relatively low control energy even under high-pressure conditions. Furthermore, during valve closure, controlled pressure relief is achieved, and the depressurized medium flows back to the main valve outlet, thereby avoiding safety risks and medium loss caused by external discharge.

[0023] In this application, the main valve assembly and the pilot valve assembly are arranged separately and connected by external pipelines. The main valve is responsible for the main on / off function of large-diameter high-pressure media, while the pilot valve is responsible for pilot switching and pressure relief guiding functions. The two are structurally independent, which facilitates material selection, precision machining, sealing assembly, and functional testing separately. It also facilitates the separate disassembly and replacement of the pilot valve or the main valve during in-service maintenance without affecting the integrity of the other component. In the separate layout, the main valve inlet 109 and the pilot valve inlet 221 are connected by a pressure-feeding pipeline. The main valve drive port 111 (main valve piston chamber 112) is connected to the second chamber 214 inside the pilot valve through the piston connection port 222. The pilot valve outlet 223 is connected to the main valve outlet 110, so that the pilot valve can achieve "upstream pressure drawing to the piston chamber" pressurization drive and "piston chamber pressure release to the downstream" closed pressure relief in the open and closed positions, respectively. On the other hand, for scenarios where installation space is limited or system integration requirements are high, the main valve assembly and the pilot valve assembly can also be integrated into the same valve body, and the above-mentioned connection relationship is formed by replacing the external pipeline with the internal flow channel of the valve body; this integration form only changes the way the flow channel is implemented, and does not change the basic principle of pilot reversing control of the main valve piston chamber pressurization / depressurization, and is still within the protection scope of this technical solution.

[0024] like Figure 1 and Figure 2As shown, the main valve assembly includes a main valve body 101, a main valve stem 103, and a main valve piston 104. The main valve piston 104 is movably engaged with the inner wall of the main valve body 101 along the axial direction of the main valve body 101. The main valve stem 103 is fixedly connected to the main valve piston 104, so that the axial displacement of the main valve piston 104 can be synchronously transmitted to the main valve stem 103 to complete the opening and closing action. A dynamic sealing structure 108 is provided between the main valve piston 104 and the main valve body 101. The dynamic sealing structure 108 forms a reliable seal while allowing the main valve piston 104 to slide back and forth, so that the pressure of the medium entering from the main valve drive port 111 mainly acts on the pressure-bearing side of the main valve piston 104, and restricts the medium from leaking radially or axially into the non-pressure-bearing cavity area inside the main valve body 101, thereby stably forming the pressure difference required to drive the main valve stem 103. The main valve body 101 has a main valve inlet 109, a main valve outlet 110, and a main valve drive port 111. The main valve drive port 111 is connected to the pressure side of the main valve piston 104 to introduce the pressure medium adjusted by the pilot valve assembly into the pressure side of the main valve piston 104. The main valve inlet 109 is sealed with an inlet connector 102 for communication with the upstream channel through a static sealing structure 107, ensuring the sealing and reliability of the connection with the upstream channel. An annular sealing protrusion is provided inside the main valve body 101, and the main valve stem 103 has a sealing end face for cooperating with the sealing protrusion. When the main valve stem 103 moves axially to the closed position, the sealing end face and the sealing protrusion form a sealing pair to cut off the communication between the main valve inlet 109 and the main valve outlet 110. When the main valve stem 103 moves axially to the open position, the sealing pair releases the sealing state to establish a medium flow path between the main valve inlet 109 and the main valve outlet 110.

[0025] like Figure 3 and Figure 4 As shown, the pilot valve assembly includes a pilot valve body 201 and a pilot valve stem 203. The pilot valve body 201 has an axially formed through hole to accommodate the pilot valve stem 203 and provide guidance for it. The pilot valve stem 203 reciprocates linearly along the axial direction of the pilot valve body 201. To construct a graded chamber within a limited axial dimension and improve pressure bearing and sealing reliability, a pilot valve seat 202 is coaxially connected to the bottom of the pilot valve body 201 to seal the bottom of the pilot valve body 201. The bottom sidewall of the pilot valve body 201 gradually expands from top to bottom to form a stepped flared structure, while the sidewall of the pilot valve seat 202 gradually narrows from bottom to top to form a stepped constricted structure. The stepped sidewalls of the two interlock to achieve coaxial positioning and axial limiting, and to make the outer wall of the pilot valve seat 202 gradually fit against the inner wall of the pilot valve body 201. A static sealing structure 107 is provided at any step in the mating interface to form a reliable static seal between the pilot valve seat 202 and the pilot valve body 201, preventing bypass leakage between the internal chamber of the pilot valve and the outside or adjacent chambers. At the same time, the step fastening structure disperses the pressure load and suppresses the relative displacement caused by pressure pulsation, improving the impact resistance of the connection.

[0026] A first annular protrusion 207 is provided on the inner wall of the pilot valve body 201. The first annular protrusion 207 protrudes inward along the radial direction of the pilot valve body 201 and provides a sealing contact reference surface for the valve stem boss. Since the outer wall of the pilot valve seat 202 is in contact with the inner wall of the pilot valve body 201 and the inner wall of the pilot valve seat 202 forms an inward protruding structure relative to the inner wall of the pilot valve body 201, the inward protruding part of the side wall of the pilot valve seat 202 is defined as the second annular protrusion 208. The first annular protrusion 207 and the second annular protrusion 208 are spaced apart along the axial direction and together define the cavity boundary inside the pilot valve. The pilot valve stem 203 is provided with a first boss 203a, a second boss 203b and a third boss 203c that are radially enlarged along the axial direction. A dynamic sealing structure 108 is provided between the outer wall of the first boss 203a and the inner wall of the pilot valve body 201, and a dynamic sealing structure 108 is provided between the outer wall of the third boss 203c and the inner wall of the pilot valve seat 202, so that the pilot valve stem 203 can still maintain the pressure isolation of the corresponding chamber and the directional flow of the medium during the reciprocating motion. The second protrusion 203b is located between the first annular protrusion 207 and the second annular protrusion 208, and forms two sets of switchable sealing contact interfaces with the first annular protrusion 207 and the second annular protrusion 208 respectively. Under the structural constraints, the first annular protrusion 207 and the first protrusion 203a form a first chamber 213, the first annular protrusion 207 and the second annular protrusion 208 form a second chamber 214, and the second annular protrusion 208 and the third protrusion 203c form a third chamber 215. The three chambers are arranged sequentially in the axial direction and achieve a state switching of "chamber isolation - chamber connection" when the valve stem position changes, thereby completing different flow path combinations with a single guide valve stem displacement.

[0027] The pilot valve body 201 has a pilot valve inlet 221, a piston communication port 222, a pilot valve outlet 223, and a pilot valve drive port 210. The pilot valve drive port 210 is connected to the pressure-bearing side of the pilot valve stem 203 and is used to connect to an external control air source to apply axial driving force to the pilot valve stem 203. The two ends of the pilot valve inlet 221 are connected to the first chamber 213 and the main valve inlet 109, respectively, so that the first chamber 213 receives the medium pressure from the upstream channel of the main valve. The two ends of the piston communication port 222 are connected to the second chamber 214 and the main valve drive port 111, respectively, so that a pressure transmission channel is established between the second chamber 214 and the main valve drive port 111. The two ends of the pilot valve outlet 223 are connected to the third chamber 215 and the main valve outlet 110, respectively, so that the third chamber 215 is connected to the downstream channel of the main valve. Based on the above interface and chamber arrangement, the pilot valve stem 203 can pressurize or close and depressurize the main valve drive port 111 when it is in different valve positions, and the depressurized medium is directed to the downstream instead of being discharged to the atmosphere.

[0028] When the pilot valve stem 203 is in the open position, the bottom surface of the second boss 203b and the second annular protrusion 208 form a sealing contact, thereby cutting off the communication between the third chamber 215 and the second chamber 214 and sealing the third chamber 215; at the same time, a channel is formed between the second boss 203b and the first annular protrusion 207, so that the first chamber 213 and the second chamber 214 are connected. At this time, the medium on the main valve inlet 109 side enters the first chamber 213 and the second chamber 214 sequentially through the pilot valve inlet 221 and is transmitted to the main valve drive port 111 through the piston communication port 222. The pressure acts on the pressure-bearing side of the main valve piston 104, generating an axial thrust, which drives the main valve piston 104 and the main valve stem 103 fixedly connected to it to move in the valve opening direction, causing the sealing end face of the main valve stem 103 to disengage from the sealing protrusion of the main valve body 101. The main valve inlet 109 and the main valve outlet 110 are connected, and the medium flows from the main valve inlet 109 to the main valve outlet 110 along the main flow channel. During this valve opening process, the dynamic sealing structure 108 between the main valve piston 104 and the main valve body 101 maintains the isolation between the main valve drive port 111 and the main flow channel in the main valve body 101, and the two dynamic sealing structures 108 on the pilot valve stem 203 maintain the stability of the chamber boundaries, thereby ensuring the effectiveness of the drive pressure transmission and the consistency of the response.

[0029] When the pilot valve stem 203 switches to the closed position, the top surface of the second boss 203b forms a sealing contact with the first annular protrusion 207, isolating the first chamber 213 from the second chamber 214 and preventing upstream pressure from continuing to flow into the main valve drive port 111. Simultaneously, a communication channel is formed between the second boss 203b and the second annular protrusion 208, connecting the second chamber 214 to the third chamber 215. At this time, the medium in the main valve drive port 111 enters the second chamber 214 through the piston communication port 222, then flows into the third chamber 215 and is introduced to the main valve outlet 110 side through the pilot valve outlet 223, achieving the sealing and pressure relief of the main valve drive port 111. As the pressure at the main valve drive port 111 is released, the pressure-bearing side of the main valve piston 104 no longer maintains the opening thrust. Under the action of the internal pressure difference and structural reset force, the main valve stem 103 moves towards the valve closing direction until the sealing end face of the main valve stem 103 and the sealing protrusion of the main valve body 101 form a reliable sealing contact. The main valve inlet 109 and the main valve outlet 110 are cut off, completing the shut-off function. Since the pressure relief path is directed to the downstream main valve outlet 110 side, the medium is not discharged to the outside during the valve closing and pressure relief process. The medium in the main valve drive port 111 is still within the closed loop of the system. This reduces the risk of combustion and explosion caused by the discharge of combustible / combustion-supporting media, the risk of cold loss and frost damage caused by the discharge of low-temperature media, the risk of pollution caused by the discharge or backflow of high-purity media, and the risk of leakage and diffusion of toxic and corrosive media from the source. At the same time, the rapid pressure relief at the main valve drive port 111 reduces the transient pressure difference impact and extrusion wear on the main valve sealing pair, which is beneficial to improving the sealing stability and life consistency under high pressure, large pressure difference and frequent opening and closing conditions.

[0030] Regarding the sealing configuration, the dynamic sealing structure 108 and static sealing structure 107 of the main valve assembly and pilot valve assembly are matched and selected according to the medium pressure level, temperature range, and physical and chemical properties of the medium. The dynamic sealing structure 108 is used at the interface between the valve stem or piston and the relative movement interface to maintain chamber isolation and pressure maintenance under reciprocating motion conditions; the static sealing structure 107 is used at the fixed connection interface to ensure that the connection between the pilot valve seat 202 and the pilot valve body 201, etc., maintains the sealing integrity under high pressure load. The sealing form can be an O-ring, a plug ring, or a combination of gaskets, and the sealing material is not limited to a single material to adapt to different working conditions such as liquid oxygen, liquid hydrogen, high-temperature fuel gas, and corrosive chemical media. For ambient temperature media, the dynamic sealing structure 108 uses nitrile rubber or fluororubber to achieve stable dynamic sealing performance while taking into account both media resistance and resilience. The static sealing structure 107 uses a polytetrafluoroethylene gasket to reduce assembly stress concentration and improve chemical stability. For low temperature or high temperature media, the dynamic sealing structure 108 uses a spring-loaded sealing ring to compensate for gap changes caused by thermal contraction or thermal expansion and maintain contact pressure. The static sealing structure 107 uses a metal gasket to improve temperature resistance and creep resistance, so that the valve can maintain reliable sealing and controllable opening and closing response under wide temperature range and high pressure conditions.

[0031] This embodiment focuses on the kerosene on / off control of a liquid rocket engine propellant supply system, designed for a flow rate of 4 kg / s and a pressure of 50 MPa. To balance high-pressure sealing reliability and assembly repeatability, a copper gasket is used for the static seal to achieve stable metal-to-metal contact sealing performance. For the dynamic seal, a nitrile rubber O-ring combined with a PTFE retaining ring is used to suppress the extrusion gap of the sealing ring under high pressure differential and reduce reciprocating friction. The seal selection in this embodiment can be adjusted according to different media and temperature boundaries: when applied to cryogenic propellant systems such as liquid oxygen and liquid hydrogen, modified PTFE, chlorotrifluoroethylene, or cryogenic metal materials are preferred to ensure elasticity retention and sealing contact stress under cryogenic contraction conditions; when applied to high-temperature fuel gas or highly corrosive chemical media, flexible graphite composite gaskets or corrosion-resistant alloy C-rings are preferred to improve sealing stability under temperature, corrosion, and thermal cycling conditions. By matching the sealing material and structural form with the physical and chemical properties of the medium, the valve can maintain reliable sealing and controllable opening and closing in harsh environments such as high pressure, cryogenic, high temperature and corrosion.

[0032] Furthermore, a main valve piston cover 106 is added to the main valve assembly to limit the pressure space of the main valve piston 104. The main valve piston cover 106 and the main valve body 101 are sealed together at the periphery of the main valve drive port 111, thereby closing the outer opening of the main valve drive port 111, so that the area where the main valve drive port 111 is located and the pressure side of the main valve piston 104 together form a relatively independent main valve piston chamber 112. The main valve piston chamber 112 provides a stable pressure-bearing volume for the driving medium and limits the pressure action boundary, avoiding the unorganized diffusion of the driving medium on the outside of the valve body, which would affect the pressure build-up efficiency; at the same time, a first through hole 122 is opened on the main valve piston cover 106, so that the main valve piston chamber 112 is fluidly connected to the piston communication port 222 of the pilot valve assembly through the first through hole 122. With this structure, the pressure switching caused by the connection / isolation of the second chamber 214 by the pilot valve assembly can be transmitted more directly to the main valve piston chamber 112, improving the response consistency of the main valve piston 104 during the pressure and pressure relief process, and reducing the impact of external pipeline layout on control characteristics.

[0033] Furthermore, the main valve assembly is equipped with a main valve reset element 105 to provide a reliable reset driving force and low-pressure sealing preload after the main valve drive chamber is depressurized. One end of the main valve reset element 105 is fixed to the internal positioning structure of the main valve body 101, and the other end abuts against the back pressure side or non-pressure side end face of the main valve piston 104. This allows the main valve piston 104 to return along the valve closing direction under the action of the reset element when the pressure in the drive chamber decreases or disappears, and drives the main valve stem 103 to form a stable sealing contact between its sealing end face and the sealing protrusion inside the main valve body 101. The main valve reset element 105 uses a spring, which can provide continuously varying reset force within a small stroke. This not only ensures sufficient sealing specific pressure at the valve closing end to compensate for insufficient pressure difference under low-pressure conditions, but also maintains repeatability in high-pressure systems with frequent opening and closing, reducing micro-opening and closing phenomena caused by vibration or pressure fluctuations, thereby improving shut-off reliability and sealing life.

[0034] To ensure the reset component maintains stable elasticity under harsh media conditions and avoids corrosion or low-temperature embrittlement, in this embodiment, the main valve stem 103 is also sealed to the inner wall of the main valve body 101 via a dynamic sealing structure 108, forming an independent sealing barrier between the outer periphery of the main valve stem 103 and the inner wall of the valve body. Based on the dynamic seals between the main valve piston 104 and the main valve body 101, and between the main valve stem 103 and the main valve body 101, a closed main valve reset component chamber 113 is formed between the two sealed connection points. The main valve reset component 105 is installed in the main valve reset component chamber 113 and isolated from the media, thereby reducing the chemical reaction and temperature shock of the media on the spring material and improving the long-term reliability of the main valve reset component 105. Correspondingly, the main valve body 101 has a through hole inside for guiding the piston and valve stem. The diameter of this through hole can be segmented along the axial direction: in the area where it mates with the main valve piston 104, the diameter of the through hole forms a clearance fit with the main valve piston 104 to meet the requirements for piston guidance and dynamic seal compression; in the area where it seals with the main valve stem 103, the diameter of the through hole forms a clearance fit with the main valve stem 103 to meet the requirements for stem guidance, friction control, and dynamic seal stability. This segmented diameter design helps to balance the load-bearing guiding stiffness of the piston section with the low-friction motion characteristics of the valve stem section, and provides a more controllable installation compression ratio for both dynamic seals.

[0035] Furthermore, to simplify the connection of internal and external pipelines and improve the integration of pressure tapping and pressure relief flow paths, a pressure tapping port 121 is opened on the side wall of the main valve inlet 109, so that the main valve inlet 109 and the pilot valve inlet 221 are directly connected. After the medium in the upstream channel enters the main valve inlet 109, it enters the pilot valve inlet 221 through the pressure tapping port 121 and then enters the first chamber 213 of the pilot valve, thereby providing a stable pressure source for pressurizing the main valve piston chamber 112 when the pilot valve is in the open position. Correspondingly, a pressure relief port 123 is opened on the side wall of the main valve outlet 110, so that the main valve outlet 110 and the pilot valve outlet 223 are connected. When the pilot valve is in the closed position and connected to the second chamber 214 and the third chamber 215, the medium in the main valve drive port 111 (main valve piston chamber 112) enters the pilot valve body 201 through the piston connection port 222 and is discharged into the pressure relief port 123 through the pilot valve outlet 223, and then flows into the downstream channel through the main valve outlet 110. By setting pressure inlet 121 and pressure relief outlet 123 on the main valve inlet 109 and main valve outlet 110 respectively, the supply and pressure relief of the driving medium are both guided inside the valve body. The pressure relief medium is recovered to the downstream instead of being discharged to the atmosphere. This maintains the closed circulation and cleanliness of the system medium, and significantly reduces the risk of flammable, low temperature, high purity or toxic media escaping during the valve closure and pressure relief process. At the same time, it reduces the number of external pipelines and connection points, reduces the probability of assembly leakage and improves the safety and applicability of the entire valve under high pressure and harsh conditions.

[0036] Furthermore, the main valve piston 104 and the main valve stem 103 are designed using the principle of "area difference force amplification": the main valve piston 104 is configured with an effective pressure-bearing area larger than the sealing end face area of ​​the main valve stem 103. This ensures that when the medium pressure in the main valve drive port 111 acts on the pressure-bearing side of the main valve piston 104, a net driving force is generated along the valve opening direction. This net driving force originates from the product of pressure and effective pressure-bearing area. Under the same driving pressure conditions, the thrust obtained by the main valve piston 104 is significantly higher than the reverse pressure component acting on the sealing end face of the main valve stem 103, thus establishing a "valve opening priority" driving margin mechanically. To ensure the stability of this force relationship, the effective pressure-bearing area is based on the pressure action boundary defined by the dynamic sealing structure 108 on the pressure-bearing side of the main valve piston 104, and the sealing end face area of ​​the main valve stem 103 is based on the pressure-bearing projection area of ​​the sealing pair formed by it and the sealing protrusion of the main valve body 101. The area difference between the two allows the main valve to be directly driven by the system medium pressure after the pilot valve is turned on.

[0037] When the pilot valve is in the open position, the medium at the main valve inlet 109 enters the first chamber 213 of the pilot valve through the pilot valve inlet 221 and connects to the second chamber 214. Then, it enters the main valve drive port 111 through the piston connection port 222, causing the main valve piston chamber 112 to quickly establish driving pressure. Since the main valve piston 104 has a larger effective pressure-bearing area, the thrust generated by the main valve piston 104 in the opening direction under the driving pressure can overcome the comprehensive resistance in the closing direction and form a positive acceleration. The comprehensive resistance includes the reset force applied by the main valve reset component 105 to the main valve piston 104, the contact preload at the sealing pair of the main valve stem 103, the frictional resistance generated by the guide fit between the valve stem and the valve body, and the fluid reaction force generated by the medium on the valve stem structure. The net driving force obtained through the area difference design is not only used to overcome the above-mentioned resistance, but also to complete the linkage displacement of the main valve piston 104 and the main valve stem 103 within a short stroke, so that the sealing end face is separated from the sealing protrusion and the main flow channel switching between the main valve inlet 109 and the main valve outlet 110 is established, thereby realizing the rapid opening of the main valve.

[0038] Based on this structure and force mechanism, the opening of the main valve does not rely on external motors, hydraulic cylinders, or pneumatic actuators to apply additional mechanical work to the main valve body. Instead, it uses the switching of the pilot valve as a trigger condition, utilizing the existing medium pressure in the pipeline to complete the self-driven opening of the main valve. Because the pressurization channel controlled by the pilot valve is short, the volume of the main valve piston chamber 112 is controllable, and the main valve piston 104 has a large pressure-bearing area, the process of establishing driving pressure and reversing force balance can be completed within milliseconds. This allows the response time of the main valve switching from the closed state to the connected state to the millisecond level. This rapid response characteristic has significant advantages in applications requiring high-frequency, short-pulse, and precise proportioning control. It can meet the control requirements of liquid rocket engine propellant valves for millisecond-level opening and closing and dynamic adjustment. Simultaneously, it reduces system size, weight, and potential failure points without increasing the main valve actuator, thereby improving the reliability and safety margin of the high-pressure fluid system.

[0039] Furthermore, to enhance the sealing capacity and resistance to temperature changes under high-pressure shut-off conditions, the sealing end face of the main valve stem 103 and the sealing protrusion within the main valve body 101 form a metal wire seal pair or a metal conical wire seal pair. The metal wire seal achieves a high contact specific pressure through local line contact, effectively suppressing media penetration under high pressure differential conditions; the conical wire seal provides a more precise self-centering guide during axial compression, making the specific pressure distribution in the line contact area more stable. In addition, by using a clearance fit between the main valve body 101, the main valve piston 104, and the main valve stem 103, the sealing pair possesses a certain degree of angular self-adaptation capability during compression. When the valve stem is subjected to uneven load, thermal expansion and contraction, or manufacturing and assembly errors cause slight coaxiality deviations, the valve stem end can undergo limited angular adjustment within the clearance range, ensuring that the metal wire seal remains effectively fitted, thereby reducing the risk of localized chipping and uneven wear, and improving sealing stability under repeated high-pressure opening and closing.

[0040] Furthermore, to achieve reliable isolation and communication between the chambers under different reversing positions of the pilot valve, the second boss 203b on the pilot valve stem 203 constructs annular sealing interfaces on its two axially opposite end faces: the top surface of the second boss 203b cooperates with the first annular protrusion 207 on the inner wall of the pilot valve body 201, forming a first annular sealing pair when the pilot valve stem 203 is in the closed position; the bottom surface of the second boss 203b cooperates with the second annular protrusion 208, forming a second annular sealing pair when the pilot valve stem 203 is in the open position. Two sets of annular sealing pairs are arranged back and forth along the axial direction of the pilot valve, so that the second boss 203b selectively fits with the annular protrusion through its end face during the reversing stroke, thereby effectively isolating the first chamber 213 or the third chamber 215 respectively. This ensures that the pilot valve can reliably isolate the third chamber 215 and connect the first chamber 213 and the second chamber 214 when the valve is open, and reliably isolate the first chamber 213 and connect the second chamber 214 and the third chamber 215 when the valve is closed, thus avoiding insufficient drive pressure or incomplete pressure relief caused by cross-cavity.

[0041] Furthermore, both the first and second annular sealing pairs employ metal wire sealing pairs or metal conical surface wire sealing pairs. Specifically, the contact areas between the first annular protrusion 207 and the top surface of the second boss 203b, and between the second annular protrusion 208 and the bottom surface of the second boss 203b, are defined as circumferentially continuous line contact or near-line contact. This significantly increases the sealing specific pressure under the same axial load, facilitating stable end-face sealing under high pressure differential conditions. For the metal wire sealing pair, the top of the annular protrusion forms a narrow ridge or arc ridge and presses against the end face of the second boss 203b. For the metal conical surface wire sealing pair, the end face of the annular protrusion or the second boss 203b is set as a conical surface and forms a line contact feature with the corresponding end face. Through the conical angle fit, a self-centering effect is generated during the pressing process, improving the sealing fit consistency when the valve stem has minor coaxiality errors or thermal deformation, thereby improving sealing repeatability and anti-vibration loosening ability.

[0042] Furthermore, the pilot valve assembly includes a pilot valve piston 204 and a cooperating pilot valve reset component 205 to convert the pressure of the external control gas source into the axial displacement of the pilot valve stem 203. The pilot valve piston 204 is arranged axially along the pilot valve body 201, and its outer circumferential surface forms a slidable sealing fit with the inner wall of the pilot valve body 201 through a dynamic sealing structure 108. This ensures smooth reciprocating movement of the pilot valve piston 204 while preventing control gas from entering the valve medium passage along the inner wall of the pilot valve body 201. The pilot valve stem 203 is fixedly connected to the pilot valve piston 204, and the two move synchronously in the axial direction, so that the pilot valve stem 203 switches between the open valve position and the closed valve position under the drive of the pilot valve piston 204; wherein, the sealing fit between the first boss 203a of the pilot valve stem 203 and the inner wall of the pilot valve body 201 is still used to define the boundary of the first chamber 213 and form a reliable isolation from the upstream medium, thereby forming a clear partition between the control gas side and the medium side in structure, avoiding the control gas from disturbing the medium flow path.

[0043] Furthermore, the pilot valve reset component 205 is disposed inside the pilot valve body 201 and applies an elastic preload force to the pilot valve piston 204 along the pilot valve axis. One end of the pilot valve reset component 205 is fixed to the pilot valve body 201, and the other end abuts against the end face of the pilot valve piston 204. Thus, when control gas is input through the pilot valve drive port 210, the pilot valve piston 204 overcomes the elastic force of the reset component under the action of gas pressure, generates axial displacement, and drives the pilot valve stem 203 to switch to the open position. When the control gas is removed, the pressure in the pilot valve piston cavity decreases, and the pilot valve reset component 205 releases elastic potential energy to push the pilot valve piston 204 back in the opposite direction, so that the pilot valve stem 203 stably returns to the closed position, realizing the inherently safe working mode of "self-reset upon gas loss". In this embodiment, the pilot valve reset component 205 is a spring. The spring's preload and elastic coefficient are set in accordance with the stroke requirements of the pilot valve stem 203, so that the reset process has sufficient return driving force. At the same time, it provides the necessary preload to the relevant sealing pairs of the pilot valve stem 203 in the valve-closed position, so as to improve the stability of the reversing positioning and reduce the risk of internal leakage caused by micro-vibration.

[0044] To improve the reliability of the pilot valve reset component 205 in harsh media environments, the pilot valve reset component 205 is arranged in a closed chamber isolated from the media. Specifically, a closed pilot valve reset component chamber 212 is formed between the dynamic sealing connection between the pilot valve piston 204 and the pilot valve body 201 and the sealing connection between the first boss 203a and the pilot valve body 201. This chamber is located axially within the isolation zone between the control gas side and the media side. The pilot valve reset component 205 is installed in this chamber and does not come into contact with the media inside the valve, thereby avoiding the impact of factors such as low-temperature media embrittlement, corrosive media erosion, or high-purity media contamination on the reset component, reducing the probability of spring fatigue, jamming, or performance drift, and enabling the pilot valve to maintain consistent opening and closing mechanical characteristics and reversing response under long-term cyclic operation conditions.

[0045] Furthermore, the pilot valve assembly is also provided with a pilot valve piston cover 206 to form an independent pilot valve piston chamber 211. The pilot valve piston cover 206 is sealed to the periphery of the pilot valve drive port 210 through a static sealing structure 107 and closes its outer opening. The pilot valve piston 204 forms a slidable sealing fit with the inner wall of the pilot valve piston cover 206 through a dynamic sealing structure 108, so that the area of ​​the pilot valve drive port 210 between the pilot valve piston cover 206 and the pressure-bearing side of the pilot valve piston 204 forms a pilot valve piston chamber 211 for accommodating control gas. A second through hole 209 is opened on the pilot valve piston cover 206, and the second through hole 209 communicates with the pilot valve piston chamber 211. External control gas enters the pilot valve piston chamber 211 through the second through hole 209 and acts on the pressure-bearing surface of the pilot valve piston 204, thereby achieving controlled pressurization and depressurization of the pilot valve piston 204 without changing the flow path of the medium inside the valve. By limiting the intake path of the control gas to the sealed space formed by the pilot valve piston cover 206 and the pressure side of the pilot valve piston 204, it is not only convenient to achieve reliable sealing and standardized connection at the interface, but also to make the isolation boundary between the control gas and the medium clear and controllable, which is conducive to improving the repeatability of the pilot valve action and the overall sealing safety of the system.

[0046] Furthermore, to ensure stable pressure balance characteristics of the pilot valve stem 203 under different operating conditions, the annular sealing boundaries corresponding to the two end faces of the first boss 203a, the third boss 203c, and the second boss 203b adopt a unified sealing diameter design. Specifically, the sealing diameters of the first boss 203a, the third boss 203c, the sealing diameter of the sealing pair formed by the top surface of the second boss 203b and the first annular protrusion 207, and the sealing diameter of the sealing pair formed by the bottom surface of the second boss 203b and the second annular protrusion 208 are all set to be the same and denoted as D1. To meet the structural constraint of a uniform sealing diameter, the inner bore of the pilot valve body 201 is arranged with a variable diameter along the axial direction: in the area where it forms a dynamic sealing fit with the first boss 203a, the bore diameter is set to D1 to ensure that the outer circumferential sealing line of the first boss 203a falls on the same reference diameter of the inner bore of the pilot valve body 201; in the area where it connects with the pilot valve seat 202, the inner bore diameter of the pilot valve body 201 is increased to accommodate the assembly and sealing structure of the pilot valve seat 202, and the inner bore diameter of the pilot valve seat 202 is also set to D1, so that the dynamic seal of the third boss 203c at the inner bore of the valve seat also falls on the reference diameter D1.

[0047] Furthermore, in order to form a controllable differential relationship of the pressure-bearing area of ​​the pilot valve stem 203, the outer diameter of the second boss 203b is set to D3, the body diameter of the pilot valve stem 203 is set to D2, and a tapered transition is provided between the end face of the second boss 203b and the diameter of the pilot valve stem 203 to reduce fluid scouring and stress concentration and improve the guiding stability of the valve stem during movement.

[0048] With the valve closed, the medium enters the first chamber 213 through the pilot valve inlet 221 and exerts an axial load on the pilot valve stem 203 within the first chamber 213. Since the sealing diameter of the first boss 203a is D1 and the diameter of the pilot valve stem 203 is D2, the effective pressure-bearing annular areas of the pilot valve stem 203 at both ends of the first chamber 213 are the same, both being π / 4 × (D1²) The pressure at both ends is opposite, and the net axial force generated by the first chamber 213 cancels each other out. Simultaneously, the post-valve pressure at the second chamber 214 and the third chamber 215 acts on the annular pressure area formed by the relevant end face of the second boss 203b and the stem portion of the pilot valve 203, respectively. The differential pressure-bearing area at the second chamber 214 related to the second boss 203b can be expressed as π / 4 × (D3²). D1²), the corresponding force direction points towards the valve opening direction; the differential bearing area at the third chamber 215 related to the second boss 203b and the rod diameter can be expressed as π / 4×(D3²). D2²), the corresponding force direction points towards the valve closing direction, and at the same time, the annular pressure area at the third chamber 215 defined by D1 and D2 is π / 4×(D1²). The direction of force corresponding to D2² points towards the valve opening direction. By structurally pairing the pressure-bearing annular areas in the direction and matching them numerically, the axial component of the pressure after the valve on the pilot valve stem 203 cancels each other out. This ensures that the pilot valve stem 203 is basically unaffected by the net thrust caused by the high-pressure medium when the valve is closed, thereby avoiding self-excitation displacement of the valve stem or abnormal pressurization of the sealing pair caused by the increase in medium pressure.

[0049] In the open position, the first chamber 213 and the second chamber 214 are connected, and the medium pressure acts simultaneously on the corresponding pressure-bearing areas of the pilot valve stem 203 within the first chamber 213 and the second chamber 214. Based on D1 as a uniform sealing diameter, the annular pressure-bearing area corresponding to the valve stem at the first chamber 213 remains π / 4 × (D1²). D2²), the direction of its force points towards the valve closing direction; at the second chamber 214, there is an annular pressure-bearing area π / 4×(D3²) defined by D3 and D2. D2²), the direction of its force points towards the valve opening direction, and on the other hand, there is an annular bearing area π / 4×(D3²) defined by D3 and D1. D1²), whose force direction points towards the valve closing direction, and the three components achieve axial force balance under the geometric difference relationship. After the third chamber 215 is connected to the pilot valve outlet 223, the medium pressure on the pilot valve outlet 223 side of the third chamber 215 is limited to the effective pressure-bearing annular area corresponding to both ends of the valve stem at the valve stem by π / 4×(D1²). D2²), and the forces are opposite in direction, so that the net axial force generated by the third chamber 215 on the valve stem is also canceled out. Therefore, regardless of whether the valve stem is in the open or closed position, the axial resultant force generated by the high-pressure medium in each chamber is structurally balanced. The switching process of the pilot valve stem 203 can be completed by mainly overcoming the resistance of the reset element and the sealing friction resistance. The driving demand is weakly correlated with the change of medium pressure.

[0050] Based on the aforementioned structural design with full pressure balance, the pilot valve can still achieve stable reversing using a small-sized drive mechanism under large-diameter and high-pressure differential conditions. This fundamentally reduces the pressure level and size requirements of the control gas system and facilitates the lightweighting and miniaturization of the entire valve. Since the pilot valve stem 203 does not bear the net axial thrust that increases significantly with the medium pressure during operation, the output force required by the pilot valve piston 204 is mainly used to overcome the spring preload and dynamic seal friction. This enables reliable control of the on / off of high-pressure, high-flow-rate media at lower control gas pressures. For example, a pilot valve piston 204 with a diameter of approximately 15 mm and a control gas pressure of approximately 3 MPa can be used to achieve reversing control of a medium circuit with a diameter of approximately 20 mm and a pressure of approximately 50 MPa. This significantly improves the system integration and safety margin in scenarios such as aerospace propulsion, hydrogen energy storage and transportation, and high-pressure chemical processes. Meanwhile, the design that the inner diameter of the pilot valve body 201 and the pilot valve seat 202 is D1 makes the geometric boundary of pressure balance stable and controllable, reduces the influence of assembly tolerance on the pressure area difference, improves the consistency of pressure balance, and thus further enhances the reliability and repeatability of the pilot valve under conditions of frequent opening and closing, drastic temperature changes and complex media properties.

[0051] The high-pressure shut-off valve in this embodiment is normally closed. Initially, when the valve is closed, the pilot valve drive port 210 is not connected to the control gas, and the pilot valve stem 203 remains in the closed position under the action of the pilot valve spring. The pilot valve stem 203 cuts off the passage between the pilot valve inlet 221 and the piston communication port 222, while simultaneously connecting the piston communication port 222 and the pilot valve outlet 223. This allows the medium in the main valve piston chamber 112 to be guided along the piston communication port 222 through the pilot valve to the main valve outlet 110, achieving closed pressure relief. After the pressure in the main valve piston chamber 112 is released, the main valve spring provides a reset force and a sealing preload force, pushing the main valve piston 104 to drive the main valve stem 103 back to its original position. The sealing end face of the main valve stem 103 presses against the sealing protrusion of the main valve body 101, cutting off the main valve inlet 109 and the main valve outlet 110.

[0052] When opened, the pilot valve drive port 210 inputs control gas to push the pilot valve stem 203 to switch to the open position: the pilot valve cuts off the pressure relief passage from the piston connection port 222 to the pilot valve outlet 223, and at the same time connects the pilot valve inlet 221 and the piston connection port 222, so that the high pressure medium of the main valve inlet 109 enters the main valve piston chamber 112 through the pilot valve; since the effective pressure bearing area of ​​the main valve piston 104 is larger than the sealing end face area of ​​the main valve stem 103, the opening thrust formed by the piston chamber pressure on the main valve piston 104 overcomes the main valve spring force and drives the main valve stem 103 to move axially downward to the open position, and the main valve inlet 109 and the main valve outlet 110 are connected to complete the opening.

[0053] When closed, the control gas is removed, and the pilot valve returns to the closed position under the action of the spring: the passage from the main valve inlet 109 to the main valve piston chamber 112 is cut off, and the main valve piston chamber 112 is reconnected to the main valve outlet 110 for sealing and pressure relief; after the pressure in the main valve piston chamber 112 drops, the main valve spring pushes the main valve stem 103 back to its original position and presses the sealing protrusion again, and the main valve inlet 109 is disconnected from the main valve outlet 110 to complete the closure, and the medium in the piston chamber is always guided downstream without being discharged to the outside, achieving zero leakage of the medium.

[0054] In another aspect of this application, a control method for a high-pressure shut-off valve is provided for controlling any of the above-mentioned high-pressure shut-off valves. During the valve opening control stage, control gas is introduced into the pilot valve drive port 210 to drive the pilot valve stem 203 to move in the valve opening direction. The bottom surface of the second boss 203b seals against the second annular protrusion 208 to isolate the third chamber 215 and connect the first chamber 213 and the second chamber 214. This allows the medium in the main valve inlet 109 to enter the main valve drive port 111 sequentially through the pilot valve inlet 221, the first chamber 213, and the second chamber 214 to act on the main valve piston 104, thereby connecting the main valve inlet 109 and the main valve outlet 110. During the valve closing control phase, the control gas at the pilot valve drive port 210 is removed, and the pilot valve stem 203 moves in the valve closing direction. The top surface of the second boss 203b seals against the first annular protrusion 207 to isolate the first chamber 213 and connect the second chamber 214 and the third chamber 215. This allows the medium at the main valve drive port 111 to flow sequentially through the piston connection port 222, the second chamber 214, the third chamber 215, and the pilot valve outlet 223 to the main valve outlet 110 to achieve closed pressure relief, thereby disconnecting the main valve inlet 109 and the main valve outlet 110.

[0055] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A high-pressure shut-off valve, characterized in that, Includes the main valve assembly and the pilot valve assembly; The main valve assembly includes a main valve body, a main valve piston that is axially connected to the inner wall of the main valve body, and a main valve stem that is fixedly connected to the main valve piston. The main valve body is provided with a main valve inlet, a main valve outlet, and a main valve drive port that communicates with the pressure side of the main valve piston. The main valve piston drives the main valve stem to move so that the sealing end face of the main valve stem and the sealing protrusion in the main valve body form a sealing pair for controlling the opening and closing of the main valve inlet and the main valve outlet. The pilot valve assembly includes a pilot valve body and a pilot valve stem that is axially connected to the inner wall of the pilot valve body. A first annular protrusion and a second annular protrusion are axially spaced on the inner wall of the pilot valve body. A first boss, a second boss, and a third boss are axially spaced on the pilot valve stem. The first boss and the third boss are respectively sealed to the inner wall of the pilot valve body. The second boss is located between the first annular protrusion and the second annular protrusion. The first annular protrusion and the first boss form a first chamber. The first annular protrusion and the second annular protrusion form a second chamber. The second annular protrusion and the third boss form a third chamber. The pilot valve body has a pilot valve inlet, a piston communication port, a pilot valve outlet, and a pilot valve drive port that communicates with the pressure side of the pilot valve stem. The first chamber is connected to the main valve inlet through the pilot valve inlet, the second chamber is connected to the main valve drive port through the piston communication port, and the third chamber is connected to the main valve outlet through the pilot valve outlet. The pilot valve stem has a closed position and an open position. The pilot valve drive port is used to connect or disconnect with the control air source to drive the pilot valve stem to switch between the closed and open positions. In the open position, the bottom surface of the second boss seals against the second annular protrusion to isolate the third chamber and connect the first and second chambers. This allows the medium at the main valve inlet to sequentially enter the main valve drive port through the pilot valve inlet, the first chamber, and the second chamber to act on the main valve piston, thereby connecting the main valve inlet and the main valve outlet. In the closed position, the top surface of the second boss seals against the first annular protrusion to isolate the first chamber and connect the second and third chambers. This allows the medium at the main valve drive port to sequentially flow through the piston connection port, the second chamber, the third chamber, and the pilot valve outlet to the main valve outlet to achieve closed pressure relief, thereby disconnecting the main valve inlet and the main valve outlet.

2. The high-pressure shut-off valve according to claim 1, characterized in that, The effective pressure-bearing area of ​​the main valve piston is greater than the sealing end face area of ​​the main valve stem, so that the driving force of the medium at the main valve drive port on the main valve piston in the opening direction is greater than the resistance experienced by the main valve stem in the closing direction.

3. The high-pressure shut-off valve according to claim 1 or 2, characterized in that, The main valve assembly also includes a main valve reset component. One end of the main valve reset component is fixed to the main valve body, and the other end abuts against the main valve piston. The main valve reset component is used to reset the main valve stem to the sealing end face of the main valve stem and seal against the sealing protrusion in the main valve body after the main valve is closed and depressurized.

4. The high-pressure shut-off valve according to claim 1 or 2, characterized in that, The main valve assembly also includes a main valve piston cover, which is sealed to the periphery of the main valve drive port. A first through hole is provided on the main valve piston cover, and the main valve drive port is connected to the piston communication port through the first through hole.

5. The high-pressure shut-off valve according to claim 1 or 2, characterized in that, The sealing diameter of the first boss is the same as the sealing diameter of the third boss, the top sealing diameter of the second boss, and the bottom sealing diameter of the second boss, so that the axial force of the medium on the valve stem of the pilot valve is balanced in the first chamber, the second chamber, and the third chamber.

6. The high-pressure shut-off valve according to claim 1 or 2, characterized in that, The pilot valve assembly also includes a pilot valve piston and a pilot valve reset component. The pilot valve piston is axially connected to the inner wall of the pilot valve body. The pilot valve stem is fixedly connected to the pilot valve piston. One end of the pilot valve reset component is fixed to the pilot valve body, and the other end of the pilot valve reset component abuts against the pilot valve piston. The pilot valve reset component is used to drive the pilot valve stem to reset to the closed position after the control gas is removed.

7. The high-pressure shut-off valve according to claim 1 or 2, characterized in that, The pilot valve assembly also includes a pilot valve piston cover, which is sealed to the periphery of the pilot valve drive port. A second through hole is provided on the pilot valve piston cover, which communicates with the pilot valve drive port. Control gas enters the pilot valve drive port through the second through hole to drive the pilot valve stem.

8. The high-pressure shut-off valve according to claim 1 or 2, characterized in that, A pressure inlet is provided on the side wall of the main valve inlet, and the main valve inlet is connected to the pilot valve inlet through the pressure inlet; A pressure relief port is provided on the side wall of the main valve outlet, and the main valve outlet is connected to the pilot valve outlet through the pressure relief port.

9. The high-pressure shut-off valve according to claim 1 or 2, characterized in that, The sealing pair formed by the sealing end face of the main valve stem and the sealing protrusion in the main valve body is a metal wire sealing pair or a metal conical wire sealing pair. The top surface of the second boss and the first annular protrusion form a first annular sealing pair, and the bottom surface of the second boss and the second annular protrusion form a second annular sealing pair. The first annular sealing pair and the second annular sealing pair are metal wire sealing pairs or metal conical wire sealing pairs.

10. A control method for a high-pressure shut-off valve, characterized in that, For controlling the high-pressure shut-off valve according to any one of claims 1 to 9, during the valve opening control stage, control gas is introduced into the pilot valve drive port to drive the pilot valve stem to move in the valve opening direction. The bottom surface of the second boss seals against the second annular protrusion to isolate the third chamber and connect the first chamber and the second chamber, so that the medium at the main valve inlet enters the main valve drive port in sequence through the pilot valve inlet, the first chamber and the second chamber to act on the main valve piston, thereby connecting the main valve inlet and the main valve outlet. During the valve closing control phase, the control gas at the pilot valve drive port is removed, and the pilot valve stem moves in the valve closing direction. The top surface of the second boss seals against the first annular protrusion to isolate the first chamber and connect the second and third chambers. This allows the medium at the main valve drive port to flow sequentially through the piston connection port, the second chamber, the third chamber, and the pilot valve outlet to the main valve outlet to achieve closed pressure relief, thereby disconnecting the main valve inlet and the main valve outlet.

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