Pilot-operated type self-driving fluid release valve

Abstract

The invention discloses a pilot-operated type self-driving fluid release valve, and belongs to the field of control valves. Comprising a main valve assembly, a pilot valve assembly and a one-way valve assembly. Valve bodies of the pilot valve assembly and the one-way valve assembly are integrated on a main valve body of the main valve assembly; the main valve assembly comprises a main valve body, a main valve piston, a main valve element and a main valve spring. The pilot valve assembly comprises a pilot valve air control opening, a pilot valve inlet, a pilot valve outlet channel and a pilot valve pressure relief opening. The one-way valve assembly is arranged at an outlet of the main valve and used for blocking medium backflow. Through mechanical configuration reconstruction and system integration innovation, the technical contradiction of the liquid rocket engine high-pressure gas control valve in weight, response speed and reliability is thoroughly solved.

Description

Technical Field

[0001] The present invention belongs to the field of control valves, and in particular relates to a pilot-operated self-driven fluid relief valve. Background Art

[0002] Liquid rocket engines (especially reusable models) generally use a high-pressure gas cylinder forced starting scheme, which uses high-pressure gas to drive a turbopump to achieve initial energy supply. This scheme places stringent requirements on high-pressure, high-flow gas control valves: Fast response - the start-up must be completed within milliseconds, otherwise the delay will cause the engine to fail to start; Adaptability to extreme environments - the valve body is installed near a high-temperature, high-vibration turbine pump, and the electromagnetic components are prone to failure; Lightweighting – The electromagnetic drive unit of traditional large-caliber high-pressure solenoid valves increases in weight as power increases, seriously violating engine weight reduction requirements; Reliability - High-pressure medium impact can easily cause valve core oscillation, leading to seal failure or response delay.

[0003] In current gaseous medium control valves, solenoid valves or electric stop valves with solenoid valves as pilot valves are often used. The fundamental defects are as follows: Electromagnetic direct-drive valve: Limited by the physical limits of Ampere force, high-pressure and large-diameter valves require giant electromagnets, resulting in excessive weight and a sharp drop in response speed as the diameter increases; Electric pilot stop valve: Relying on an external air source to drive the pilot valve, the system is complex, and the multi-stage transmission causes cumulative delays, which cannot meet the startup window requirements; High-temperature reliability: The magnetic properties of electromagnetic components decay in environments above 150°C, the coils are prone to breakage under vibration conditions, and the failure rate exceeds the industry tolerance threshold.

[0004] Therefore, there is an urgent need for a high-pressure gas control valve that does not require external power, is lightweight, has a millisecond-level response, and is resistant to high-temperature vibration. This is the technical bottleneck for the reliable starting of liquid rocket engines. Summary of the Invention

[0005] Technical issues to be solved: In order to avoid the shortcomings of the existing technology, the present invention provides a pilot-type self-driven fluid relief valve, which uses the fluid's own pressure difference to drive the valve, without the need for an external control gas source, thereby solving the problem of rocket engine weight reduction. At the same time, it solves the problem that the existing high-pressure gas control valve cannot meet the requirements of reliable and rapid starting of liquid rocket engines.

[0006] The technical solution of the present invention is: a pilot-operated self-propelled fluid relief valve, comprising a main valve assembly 1, a pilot valve assembly 2 and a one-way valve assembly 3; the valve bodies of the pilot valve assembly 2 and the one-way valve assembly 3 are both integrated on the main valve body 102 of the main valve assembly 1; The main valve assembly 1 comprises: The main valve body 102 has an inner cavity divided into a piston movement chamber and a medium flow chamber by a first-stage baffle 120. The medium flow chamber is divided into a first flow chamber 115 and a second flow chamber 116 by a second-stage baffle 121. The inlet of the first flow chamber 115 is the main valve inlet 114, and the outlet is the through hole of the second-stage baffle 121. The inlet of the second flow chamber 116 is the through hole of the second-stage baffle 121, and the outlet is the main valve outlet 119. The main valve piston 106 is slidably disposed in the piston movement chamber, dividing it into an elastic component chamber 117 and a main valve pressure chamber 118; The main valve core 103 passes through the first-stage baffle 120 and the second-stage baffle 121. One end is connected to the main valve piston 106, and the other end is engaged in a sealable manner with the through hole of the second-stage baffle 121 in the medium flow chamber to control the flow between the first flow chamber 115 and the second flow chamber 116. The main valve spring 105 is arranged in the elastic component chamber 117 along the direction of piston movement and abuts against the main valve piston 106; The pilot valve assembly 2 includes a pilot valve air control port 208, a pilot valve inlet 210, a pilot valve outlet channel 213 and a pilot valve pressure relief port 209, wherein: The pilot valve inlet 210 is connected to the first flow chamber 115 of the medium flow chamber; The pilot valve outlet channel 213 is connected to the main valve pressure chamber 118; The pilot valve pressure relief port 209 selectively connects the main valve pressure chamber 118 with the outside world through the pilot valve piston pressure relief channel 211; The pilot valve air control port 208 is connected to the control system to introduce control air into the pilot valve assembly to control the on and off of the pilot valve assembly; The one-way valve assembly 3 is provided at the main valve outlet 119 to block the backflow of the medium. A further technical solution of the present invention is that the force bearing area of ​​the main valve piston 106 is larger than the force bearing area of ​​the sealing end surface of the main valve spool 103, so that the opening and closing of the main valve is autonomously driven by the pressure difference of the fluid medium. A further technical solution of the present invention is that the first-stage baffle 120 is composed of a limit baffle in the middle section of the main valve body 102, a valve stem retaining ring 112, a locking washer 113 and a compression washer 104; The locking washer 113 and the compression washer 104 are threadedly matched, and the compression washer 104 is sleeved on the main valve core 103 to limit the radial shaking of the valve core; the valve stem retaining ring 112 is embedded in the groove below the compression washer 104 and sleeved on the main valve core 103.

[0007] A further technical solution of the present invention is: the pilot valve assembly 2 is a pneumatic valve, comprising a pilot valve body 201 and a pilot valve piston 202 and a pilot valve spring 205 disposed therein; The pilot valve piston 202 moves in response to the control air pressure of the pilot valve air control port 208; The pilot valve spring 205 is arranged in the pilot valve inner cavity 212 along the movement direction of the pilot valve piston 202 to drive the pilot valve piston 202 to reset; The pilot valve piston 202 synchronously controls the opening and closing of the pilot valve inlet 210 and the pilot valve outlet channel 213 , and the opening and closing of the pilot valve pressure relief port 209 when it moves.

[0008] A further technical solution of the present invention is that the pilot valve piston 202 is provided with an axially penetrating pilot valve piston pressure relief channel 211 , which connects the pilot valve outlet channel 213 with the pilot valve pressure relief port 209 when the pilot valve piston 202 is reset.

[0009] A further technical solution of the present invention is that a pilot valve cover 203 is threadedly mounted on the outer port of the pilot valve body 201 , and the screwing depth of the pilot valve cover 203 is adjustable to change the pre-compression amount of the pilot valve spring 205 , thereby adjusting the opening pressure of the pilot valve.

[0010] A further technical solution of the present invention is: the one-way valve assembly 3 includes: The one-way valve core 302 is pressed against the one-way valve inlet 307 by the one-way valve spring 306; The outlet nozzle 303 is fixed to the one-way valve body 301 through the outer nut 304; When the main valve is opened, the medium pressure pushes the one-way valve core 302 to overcome the spring force and open the flow channel. A further technical solution of the present invention is: O-rings and gaskets are used to seal all components; among them, a main valve core gasket 111 is provided between the other end of the main valve core 103 and the second-stage baffle 121; and pilot valve piston gaskets 207 are provided at both ends of the pilot valve piston 202.

[0011] A further technical solution of the present invention is: the relief valve is suitable for starting control of a liquid rocket engine, and the working medium is high-pressure gas, liquid oxygen, kerosene or nitrogen.

[0012] A control method for a pilot-operated self-driven fluid relief valve, comprising the following steps: Opening control stage: Control gas is introduced into the pilot valve air control port 208, driving the pilot valve piston 202 to overcome the elastic force of the pilot valve spring 205 and move toward the pilot valve cover 203, opening the pilot valve inlet 210 and closing the pilot valve pressure relief port 209, allowing the high-pressure medium in the first flow chamber 115 of the main valve to flow into the main valve pressure chamber 118 through the pilot valve outlet channel 213; Self-driven main valve opening stage: After the pressure in the main valve pressure chamber 118 and the first flow chamber 115 is balanced, the pressure difference between the effective pressure-bearing area of ​​the main valve piston 106 and the effective pressure-bearing area of ​​the main valve spool 103 is used to drive the main valve spool 103 to move in the opening direction, connecting the main valve inlet 114 and the main valve outlet 119; Closing control stage: the control gas of the pilot valve air control port 208 is cut off, the pilot valve spring 205 pushes the pilot valve piston 202 to return to close the pilot valve inlet 210 and open the pilot valve pressure relief port 209, and the medium in the main valve pressure chamber 118 is discharged to atmospheric pressure through the pilot valve piston pressure relief channel 211; Self-driven main valve closing stage: After the main valve pressure chamber 118 is depressurized, the main valve spool 103 is reset under the action of the elastic force of the main valve spring 105 and the medium pressure difference, cutting off the communication between the main valve inlet 114 and the main valve outlet 119.

[0013] Beneficial effects The beneficial effects of the present invention are as follows: the pilot-operated self-propelled fluid relief valve provided by the present invention, through mechanical configuration reconstruction and system integration innovation, completely solves the technical contradictions in weight, response speed and reliability of the high-pressure gas control valve of the liquid rocket engine. The specific effects are as follows: 1. Through the "area difference and pressure difference self-drive" mechanism (the force area of ​​the main valve piston > the valve core sealing surface area), the fluid's own pressure is used to drive the main valve to open and close, eliminating the electromagnetic drive unit and external air source system, and reducing the weight of the valve body; the three-dimensional embedded integrated design of the pilot valve, check valve and main valve eliminates redundant pipelines and interfaces, reducing the volume and meeting the compact layout requirements of rocket engines.

[0014] 2. The pneumatic pilot valve adopts a "direct-push piston + axial pressure relief channel" structure to control the air pressure without an intermediate transmission link, achieving a full-open / full-close time of the pilot valve of ≤10ms; the main valve uses the transient pressure balance mechanism between the main valve pressure chamber and the flow chamber, combined with the area difference to amplify the driving force, and the full-open response of the main valve is accelerated.

[0015] 3. The fully mechanical, non-electromagnetic architecture completely avoids the risks of high-temperature demagnetization of electromagnetic components and coil breakage, reducing the failure rate; The anti-sway locking structure (threaded compression washer 104 + locking washer 113) compresses the valve core radially to ensure zero sealing failure under the impact of high-pressure media.

[0016] 4. The spring-loaded locking design of the one-way valve assembly, combined with the rapid closure of the main valve, blocks the media's backflow path, preventing accidents caused by turbine reverse rotation. The self-drive mechanism requires no external power supply, and single-valve operation consumes zero power, significantly reducing the complexity and energy burden of the engine control system.

[0017] 5. The sealing system adopts an O-ring + metal / non-metallic sealing gasket composite solution, which is compatible with extreme media such as liquid oxygen, kerosene, and high-pressure nitrogen, and can be expanded to multiple fields such as aerospace, energy, and chemical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of a pilot-operated self-propelled fluid discharge valve according to an embodiment of the present invention; Figure 2 4 is a side sectional view of a pilot valve assembly in an embodiment of the present invention.

[0019] Description of the accompanying drawings: 1-main valve assembly, 101-inlet nozzle, 102-main valve body, 103-main valve core, 104-compression gasket, 105-main valve spring, 106-main valve piston, 107-piston cover, 108-jacket nut, 109-O-ring, 110-piston retaining ring, 111-main valve core sealing gasket, 112-valve stem retaining ring, 113-locking washer, 114-main valve inlet, 115-first flow chamber, 116-second flow chamber, 117-elastic component chamber, 118-main valve pressure chamber, 119-main valve outlet, 120-first stage baffle, 121-second stage baffle; 2-Pilot valve assembly, 201-Pilot valve body, 202-Pilot valve piston, 203-Pilot valve cover, 204-Outer nut, 205-Pilot valve spring, 206-O-ring, 207-Pilot valve piston sealing gasket, 208-Pilot valve air control port, 209-Pilot valve pressure relief port, 210-Pilot valve inlet, 211-Pilot valve piston pressure relief channel, 212-Pilot valve inner cavity, 213-Pilot valve outlet channel; 3-Check valve, 301-Check valve body, 302-Check valve spool, 303-Outlet nozzle, 304-Outer nut, 305-Seal, 306-Check valve spring, 307 Check valve inlet, 308 Check valve outlet. DETAILED DESCRIPTION The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0021] Based on the problems existing in the prior art, the present invention proposes a pilot-operated self-propelled fluid relief valve with a more compact structure and a smaller size. Since the force-bearing area of ​​the main valve piston is larger than the force-bearing area of ​​the main valve spool, the opening and closing of the main valve is completely controlled by the fluid medium in the main valve cavity, without the need for an additional control air source, thereby reducing the complexity of the engine system. The present invention will be described in detail below in conjunction with specific embodiments: The present invention provides a pilot-operated self-propelled fluid relief valve, comprising a main valve assembly 1, a pilot valve assembly 2, and a one-way valve assembly 3; the valve bodies of the pilot valve assembly 2 and the one-way valve assembly 3 are both integrated on the main valve body 102 of the main valve assembly 1; The main valve assembly 1 comprises: The main valve body 102 has an inner cavity divided into a piston movement chamber and a medium flow chamber by a first-stage baffle 120. The medium flow chamber is divided into a first flow chamber 115 and a second flow chamber 116 by a second-stage baffle 121. The inlet of the first flow chamber 115 is the main valve inlet 114, and the outlet is the through hole of the second-stage baffle 121. The inlet of the second flow chamber 116 is the through hole of the second-stage baffle 121, and the outlet is the main valve outlet 119. The main valve piston 106 is slidably disposed in the piston movement chamber, dividing it into an elastic component chamber 117 and a main valve pressure chamber 118; The main valve core 103 passes through the first-stage baffle 120 and the second-stage baffle 121. One end is connected to the main valve piston 106, and the other end is engaged in a sealable manner with the through hole of the second-stage baffle 121 in the medium flow chamber to control the flow between the first flow chamber 115 and the second flow chamber 116. The main valve spring 105 is arranged in the elastic component chamber 117 along the direction of piston movement and abuts against the main valve piston 106; The pilot valve assembly 2 includes a pilot valve air control port 208, a pilot valve inlet 210, a pilot valve outlet channel 213 and a pilot valve pressure relief port 209, wherein: The pilot valve inlet 210 is connected to the first flow chamber 115 of the medium flow chamber; The pilot valve outlet channel 213 is connected to the main valve pressure chamber 118; The pilot valve pressure relief port 209 selectively connects the main valve pressure chamber 118 with the outside world through the pilot valve piston pressure relief channel 211; The pilot valve air control port 208 is connected to the control system to introduce control air into the pilot valve assembly to control the on and off of the pilot valve assembly; The one-way valve assembly 3 is provided at the main valve outlet 119 to block the backflow of the medium. The present invention also includes a control method for a pilot-operated self-driven fluid discharge valve, the specific steps of which are as follows: Opening control stage: Control gas is introduced into the pilot valve air control port 208, driving the pilot valve piston 202 to overcome the elastic force of the pilot valve spring 205 and move toward the pilot valve cover 203, opening the pilot valve inlet 210 and closing the pilot valve pressure relief port 209, allowing the high-pressure medium in the first flow chamber 115 of the main valve to flow into the main valve pressure chamber 118 through the pilot valve outlet channel 213; Self-driven main valve opening stage: After the pressure in the main valve pressure chamber 118 and the first flow chamber 115 is balanced, the pressure difference between the effective pressure-bearing area of ​​the main valve piston 106 and the effective pressure-bearing area of ​​the main valve spool 103 is used to drive the main valve spool 103 to move in the opening direction, connecting the main valve inlet 114 and the main valve outlet 119; Closing control stage: the control gas of the pilot valve air control port 208 is cut off, the pilot valve spring 205 pushes the pilot valve piston 202 to return to close the pilot valve inlet 210 and open the pilot valve pressure relief port 209, and the medium in the main valve pressure chamber 118 is discharged to atmospheric pressure through the pilot valve piston pressure relief channel 211; Self-driven main valve closing stage: After the main valve pressure chamber 118 is depressurized, the main valve spool 103 is reset under the action of the elastic force of the main valve spring 105 and the medium pressure difference, cutting off the communication between the main valve inlet 114 and the main valve outlet 119.

[0022] The above technical solution is further described below with reference to the accompanying drawings: In one embodiment, referring to Figure 1 As shown, in this embodiment, a pilot-operated self-driven fluid relief valve consists of a main valve assembly 1, a pilot valve assembly 2 and a one-way valve assembly 3. The working state of the entire control valve is controlled by the pilot valve assembly 2, and the one-way valve assembly 3 is used to prevent the backflow of the fluid medium.

[0023] The main valve assembly 1 consists of an inlet nozzle 101, a main valve body 102, a main valve core 103, a main valve piston 106, a main valve spring 105, a piston cover 107, a compression washer 104, a valve stem retaining ring 112, a locking washer 113, a compression washer 104, and a jacket nut 108.

[0024] The front end of the main valve body 102 is an inlet nozzle 101, which is installed and fixed by a sleeve nut 108. The rear end of the valve body is a piston cover 107, which is installed and fixed by a sleeve nut 108. The inner cavity of the main valve is divided into a piston movement chamber and a medium flow chamber by a first-level baffle 120. The piston movement chamber is divided into an elastic component chamber 117 and a main valve pressure chamber 118 by the piston. The medium flow chamber is divided into a first flow chamber 115 and a second flow chamber 116 by a second-level baffle 121. The main valve inlet 114 is located below the first flow chamber 115, and a main valve outlet 119 is opened on the side wall of the second flow chamber 116. The main valve core 103, main valve spring 105, compression washer 104, valve stem retaining ring 112, locking washer 113 and main valve piston 106 are coaxially installed. The main valve core 103 passes through the valve stem retaining ring 112 and the compression washer 104 along the axis, and the end is installed in the groove opened along the axis of the main valve piston 106 through a thread. The main valve spring 105 is sleeved on the main valve piston 106, and the two ends are respectively against the main valve piston 106 and the compression washer 104. The valve stem retaining ring 112 is installed in the groove below the compression washer 104 and sleeved on the valve core, and the locking washer 113 is installed on the compression washer 104 through a thread. An O-ring 109 for sealing is installed between the compression gasket 104 and the main valve body 102, the first-stage baffle 120 and the main valve core 103, the main valve body 102 and the main valve piston 106, and the main valve body 102 and the piston cover 107. The main valve core sealing gasket 111 is installed in the annular groove opened in the main valve core 103 to seal the contact end surface of the main valve core 103 and the second-stage baffle 121.

[0025] Among them, the first-stage baffle 120 with sealing effect is composed of a limit baffle in the middle section of the main valve body 102, a valve stem retaining ring 112, a locking washer 113 and a compression washer 104, wherein the locking washer 113 and the compression washer 104 are in a threaded matching relationship, and the compression washer 104 is sleeved on the main valve core 103 to prevent the valve core from shaking.

[0026] The first flow chamber 115 has a circular hole on its side, connecting to the pilot valve inlet 210. The second flow chamber 116 has a main valve outlet 119 on its sidewall. The main valve spool 103 extends through the piston motion chamber and the medium flow chamber, threadedly engaging the main valve piston 106. The main valve spool 103's head protrudes outward, engaging the sealing end surface of the second-stage baffle 121. The middle section of the main valve spool 103 slides against the sealing surface of the first-stage baffle 120. The main valve piston 106 is located within the piston motion chamber, dividing the piston motion chamber into two sub-chambers. Between the main valve piston 106 and the first-stage baffle 120 is an elastic component chamber 117, with an elastic component composed mainly of the main valve spring 105 positioned along the direction of piston motion. Between the main valve piston 106 and the piston cover 107 is a main valve pressure chamber 118, with a channel on its inner wall connecting to the pilot valve outlet.

[0027] The working principle of the main valve assembly is as follows: when the valve is closed, the high-pressure medium pressure at the main valve inlet 114 and the spring force give the valve core an upward force, and the upper end surface of the protruding end of the main valve core 103 contacts and seals with the lower end surface of the second-stage baffle 121, maintaining a closed state, and blocking the fluid medium in front of the main valve core 103; when the first flow chamber 116 is connected to the pilot valve outlet channel 213 through a circular hole channel opened on the side, when the pilot valve is opened, the fluid medium can flow from the first flow chamber 115 to the main valve pressure chamber 118. At this time, the pressures in the two chambers are equal. Since the contact surface area between the main valve piston 106 and the medium is larger than the contact surface area between the main valve core 103 and the medium, the force on the main valve piston 106 is greater than the force on the main valve core 103. The main valve core 103 moves downward under the action of the medium pressure difference, and the first flow chamber 115 is connected to the second flow chamber 116, and the fluid medium can flow out from the main valve outlet 119.

[0028] Reference Figure 1 and Figure 2 As shown, the pilot valve assembly 2 is a pneumatic valve, consisting of a pilot valve body 201, a pilot valve piston 202, a pilot valve cover 203, a jacket nut 204, a pilot valve spring 205, an O-ring 206, and a pilot valve piston seal 207. The pilot valve is equipped with four valve ports: a pilot valve air control port, a pilot valve outlet, a pilot valve inlet, and a pilot valve pressure relief port. The pilot valve inlet communicates with the first fluid chamber of the main valve, the pilot valve outlet communicates with the pilot valve outlet channel, the pilot valve pressure relief port leads to the external environment, and the pilot valve air control port is connected to the control system. The pressure relief port is located in the center of the pilot valve cover, and the pilot valve piston is provided with a pressure relief channel, one end of which communicates with the pilot valve outlet and the other end with the pressure relief port.

[0029] The pilot valve body 201 is integrated into the main valve body 102. The pilot valve core 202, pilot valve cover 203, and pilot valve spring 205 are coaxially mounted. The pilot valve spring 205 is sleeved onto the pilot valve cover 203, with its ends respectively abutting the pilot valve core 202 and the pilot valve cover 203. This installation method allows the compression of the pilot valve spring 205 to be adjusted by adjusting the installation depth of the pilot valve cover 203, thereby varying the opening pressure of the pilot valve during operation. The sidewall of the pilot valve core 202 is sealed against the inner end surface of the pilot valve cover 203 and the inner cavity of the pilot valve body 201 via an O-ring 206. Pilot valve piston seals 207 are installed at both ends of the pilot valve core 202 to prevent the high-pressure medium at the pilot valve inlet 210 from entering the pilot valve inner cavity 212 when closed, and to prevent leakage from the pilot valve pressure relief port 209 during operation. An outer nut 204 is used to secure the pilot valve cover 203 to the pilot valve body 201. The pilot valve air control port 208 is connected to the control system. The pilot valve spool 202's movement is controlled by the control air pressure, thereby opening and closing the pilot valve assembly 2 and, in turn, controlling the operating state of the main valve assembly 1. An axially extending pilot valve pressure relief port 209 is defined within the pilot valve cover 203. The pilot valve piston 202 is provided with axially extending pilot valve piston pressure relief channels 211, which are uniformly distributed along the circumference. The pilot valve inlet 210 leads to the pilot valve cavity 212. A pilot valve outlet channel 213 is defined on the sidewall of the pilot valve cavity 212. This channel is located within the main valve body 102 and leads to the main valve pressure chamber 118 located behind the main valve piston 106.

[0030] The working principle of the pilot valve is as follows: after the pilot valve air control port 208 is ventilated, the pilot valve piston 202 overcomes the elastic force of the pilot valve spring 205 under the action of the control gas pressure and begins to move toward the pilot valve cover 203, the pilot valve inlet 210 is opened, and the medium in the first flow chamber 115 can flow out from the pilot valve outlet channel 213 and finally enter the main valve pressure chamber 118. After the pilot valve is fully opened, the pilot valve piston 202 contacts the pilot valve cover 203, and the pilot valve pressure relief port 209 is closed; when the pilot valve air control port 208 stops venting, the pilot valve piston 202 closes the pilot valve inlet 210 under the elastic force of the pilot valve spring 205, the medium in the first flow chamber 115 of the main valve is blocked in front of the pilot valve piston 202, the pilot valve pressure relief port 209 is in an open state, the medium in the pilot valve inner cavity flows out of the pilot valve through the pressure relief port, the pressure in the pilot valve inner cavity 212 returns to atmospheric pressure, and the pilot valve is closed.

[0031] The pilot valve has two working states: open and closed: when the control air is introduced into the control air inlet 208, the pilot valve is opened, the pilot valve piston moves in the direction of the pilot valve cover, the pilot valve inlet 210 and the pilot valve outlet channel 213 are connected, and the pilot valve outlet channel 213 and the pilot valve pressure relief port 209 are blocked; when the control air inlet 208 stops introducing the control air, the pilot valve is closed, the pilot valve piston moves 210 in the direction of the pilot valve inlet, the pilot valve inlet 210 and the pilot valve outlet channel 213 are blocked, and the pilot valve port channel 213 and the pilot valve pressure relief port 209 are connected.

[0032] The one-way valve assembly 3 consists of a one-way valve body 301, a one-way valve core 302, a one-way valve spring 306, an outer nut 304, and an outlet nozzle 303. It is installed at the main valve outlet to prevent backflow of the fluid medium at the main valve outlet. The one-way valve core 302, one-way valve spring 306, and outlet nozzle 303 are coaxially mounted. The one-way valve core 302 is sleeved within the outlet nozzle 303. The one-way valve spring 306 is sleeved over the one-way valve core 302, with its ends resting on the one-way valve core 302 and the outlet nozzle 303, respectively. The outlet nozzle 303 is mounted on the one-way valve body 301 via the outer nut 304. A sealing gasket 305 is installed between the outlet nozzle 303 and the one-way valve body 301 for sealing.

[0033] The working principle of the one-way valve is as follows: when the main valve core 103 is opened, the fluid medium gathers in front of the one-way valve core 302, pushing the one-way valve core 302 to overcome the elastic force of the one-way valve spring 306 to move, and the one-way valve core 302 opens, and the fluid medium can flow out through the one-way valve; when the main valve core 103 is closed, the one-way valve core 302 is closed under the elastic force of the one-way valve spring 306, and the fluid medium cannot flow back from the one-way valve outlet to the inner cavity of the main valve body.

[0034] In one embodiment, a pilot-operated self-propelled fluid relief valve operates as follows: Before starting a liquid rocket engine, the main valve spool 103, under the elastic force of the main valve spring 105, presses against the second-stage baffle 121, blocking the first flow chamber 115 from the second flow chamber 116. The main valve is in the closed state, and high-pressure fluid enters the first flow chamber 115 through the main valve inlet 114 and is retained. At this point, the main valve pressure chamber 118 is connected to the outside atmosphere through the pilot valve outlet channel 213, the pilot valve piston pressure relief channel 211, and the pilot valve pressure relief port 209. The pressure within the main valve pressure chamber 118 is at atmospheric pressure. Due to the pressure differential, the main valve spool 103 presses more tightly against the second-stage baffle 121, improving the sealing effect. Under the elastic force of the pilot valve spring 205, the pilot valve piston 202 presses against the pilot valve body 201, blocking the pilot valve inlet 210 from the pilot valve outlet channel 213, and the pilot valve is in the closed state. At this time, the pilot valve pressure relief port 209 is connected to the pilot valve inner cavity 212 through the pilot valve piston pressure relief channel 211. The one-way valve spool 302 is tightly attached to the one-way valve body 301 under the elastic force of the one-way valve spring 306, and the one-way valve is in a closed state, blocking the one-way valve inlet 307 and the one-way valve outlet 308.

[0035] When the liquid rocket engine starts, the control system blows pilot air into the pilot valve assembly 2 through the pilot air inlet 208. Under the action of the pilot air pressure, the pilot valve piston 202 overcomes the elastic force of the pilot valve spring 205 and moves toward the pilot valve cover 203. The pilot valve inlet 210 and the pilot valve outlet passage 211 are connected through the pilot valve inner cavity 212. The pilot valve spool 202 eventually fully engages with the pilot valve cover 203, and the pilot valve pressure relief port 209 closes. At this point, with the pilot valve assembly 2 open, the main valve's first flow chamber 115 communicates with the main valve pressure chamber 118 through the pilot valve inlet 210, the pilot valve inner cavity 212, and the pilot valve outlet passage 213. The high-pressure fluid in the first flow chamber 115 flows into the main valve pressure chamber 118 until the pressures in the two chambers equalize. Because the area of ​​the main valve spool 103 affected by the high-pressure fluid pressure is smaller than the area of ​​the main valve piston 106 in the main valve pressure chamber 118, the pressure at the rear end of the main valve spool 103 is greater than the pressure at the front end. Under the action of the pressure differential, the main valve spool 103 moves toward the main valve inlet 114. The main valve opens, connecting the first flow chamber 115 and the second flow chamber 116. The fluid enters the second flow chamber 116. The one-way valve spool 302, under the pressure of the high-pressure fluid, moves toward the one-way valve outlet 308. The one-way valve assembly 3 opens, connecting the main valve outlet 119, the one-way valve inlet 307, and the one-way valve outlet 308. The high-pressure fluid flows out of the one-way valve assembly 3 and into the turbine chamber, driving the turbine to rotate. The liquid rocket engine is started.

[0036] At the end of liquid rocket engine startup, the control system stops injecting control air from the control air inlet 208. The pilot valve piston 202, under the force of the pilot valve spring 205, moves toward the pilot valve inlet 210, blocking the pilot valve inlet 210 and the pilot valve outlet passage 213. The pilot valve pressure relief port 209, the pilot valve piston pressure relief passage 211, the pilot valve cavity 212, the pilot valve outlet passage 211, and the main valve pressure chamber 118 are now interconnected. Because the fluid pressure is significantly greater than atmospheric pressure, the high-pressure fluid in the main valve pressure chamber 118 flows out of the pilot valve pressure relief port 209, returning the pressure in the main valve pressure chamber 118 to atmospheric pressure. At this point, the main valve spool 103, driven by the pressure differential and the force of the main valve spring 105, moves toward the piston cover 107. Ultimately, the front end of the main valve spool 103 abuts against the second-stage baffle 121, isolating the first and second flow chambers 115, 116, and closing the main valve. The one-way valve core 302 is acted upon by the one-way valve spring 306 and moves toward the one-way valve inlet 307. Finally, the one-way valve core 302 closes the one-way valve inlet 307, and the main valve outlet 119 and the one-way valve outlet 308 are isolated. The one-way valve assembly 3 is closed to prevent the high-pressure fluid medium from flowing back into the main valve assembly 1. At this time, the engine start-up is completed.

[0037] In particular, the pilot-operated self-propelled fluid relief valve of the present invention is not only suitable for controlling the starting process of a liquid rocket engine, but is also suitable for controlling processes of various high-pressure gases or liquid media, such as water, kerosene, oxygen, nitrogen, etc.

[0038] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A pilot-operated self-propelled fluid relief valve, characterized in that: It comprises a main valve assembly (1), a pilot valve assembly (2) and a one-way valve assembly (3); the valve bodies of the pilot valve assembly (2) and the one-way valve assembly (3) are both integrated on the main valve body (102) of the main valve assembly (1); The main valve assembly (1) comprises: The main valve body (102) has an inner cavity divided into a piston movement chamber and a medium flow chamber by a first-stage baffle (120); the medium flow chamber is divided into a first flow chamber (115) and a second flow chamber (116) by a second-stage baffle (121); the inlet of the first flow chamber (115) is the main valve inlet (114), and the outlet is the through hole of the second-stage baffle (121); the inlet of the second flow chamber (116) is the through hole of the second-stage baffle (121), and the outlet is the main valve outlet (119); A main valve piston (106) is slidably disposed in the piston movement chamber, dividing the chamber into an elastic component chamber (117) and a main valve pressure chamber (118); The main valve core (103) passes through the first-stage baffle (120) and the second-stage baffle (121), one end of which is connected to the main valve piston (106), and the other end of which is engaged with the through hole of the second-stage baffle (121) in the medium flow chamber in a sealable manner to control the on-off between the first flow chamber (115) and the second flow chamber (116); A main valve spring (105) is disposed in the elastic component chamber (117) along the piston movement direction and abuts against the main valve piston (106); The pilot valve assembly (2) comprises a pilot valve air control port (208), a pilot valve inlet (210), a pilot valve outlet channel (213) and a pilot valve pressure relief port (209), wherein: The pilot valve inlet (210) is connected to the first flow chamber (115) of the medium flow chamber; The pilot valve outlet passage (213) is connected to the main valve pressure chamber (118); The pilot valve pressure relief port (209) selectively connects the main valve pressure chamber (118) with the outside world through the pilot valve piston pressure relief channel (211); The pilot valve air control port (208) is connected to the control system, and the control air is introduced into the pilot valve assembly to control the on and off of the pilot valve assembly; The one-way valve assembly (3) is provided at the main valve outlet (119) and is used to block the backflow of the medium.

2. A pilot-operated self-propelled fluid relief valve according to claim 1, characterized in that: The force-bearing area of ​​the main valve piston (106) is larger than the force-bearing area of ​​the sealing end face of the main valve core (103), so that the opening and closing of the main valve are autonomously driven by the pressure difference of the fluid medium.

3. The pilot-operated self-propelled fluid relief valve according to claim 1, characterized in that: The first-stage baffle (120) is composed of a limit baffle in the middle section of the main valve body (102), a valve stem retaining ring (112), a locking washer (113) and a compression washer (104); The locking washer (113) and the compression washer (104) are threadedly matched, and the compression washer (104) is sleeved on the main valve core (103) to limit the radial shaking of the valve core; the valve stem retaining ring (112) is embedded in the groove below the compression washer (104) and sleeved on the main valve core (103).

4. The pilot-operated self-propelled fluid relief valve according to claim 1, characterized in that: The pilot valve assembly (2) is a pneumatic valve, comprising a pilot valve body (201) and a pilot valve piston (202) and a pilot valve spring (205) disposed therein; The pilot valve piston (202) moves in response to the control air pressure of the pilot valve air control port (208); A pilot valve spring (205) is arranged in the pilot valve inner cavity (212) along the movement direction of the pilot valve piston (202) to drive the pilot valve piston (202) to reset; The pilot valve piston (202) moves to synchronously control the opening and closing of the pilot valve inlet (210) and the pilot valve outlet channel (213), as well as the opening and closing of the pilot valve pressure relief port (209).

5. The pilot-operated self-propelled fluid relief valve according to claim 4, characterized in that: The pilot valve piston (202) is provided with an axially penetrating pilot valve piston pressure relief channel (211), and when the pilot valve piston (202) is reset, the channel communicates with the pilot valve outlet channel (213) and the pilot valve pressure relief port (209).

6. The pilot-operated self-propelled fluid relief valve according to claim 5, characterized in that: The outer port of the pilot valve body (201) is threadedly mounted with a pilot valve cover (203), and the screwing depth of the pilot valve cover (203) is adjustable to change the pre-compression amount of the pilot valve spring (205), thereby adjusting the opening pressure of the pilot valve.

7. The pilot-operated self-propelled fluid relief valve according to claim 1, characterized in that: The one-way valve assembly (3) comprises: The one-way valve core (302) is pressed against the one-way valve inlet (307) by the one-way valve spring (306); The outlet nozzle (303) is fixed to the one-way valve body (301) via a jacket nut (304); When the main valve is opened, the medium pressure pushes the one-way valve core (302) to overcome the spring force and open the flow channel.

8. The pilot-operated self-propelled fluid relief valve according to claim 1, characterized in that: All components are sealed using O-rings and gaskets; a main valve core gasket (111) is provided between the other end of the main valve core (103) and the second-stage baffle (121); and pilot valve piston gaskets (207) are provided at both ends of the pilot valve piston (202).

9. The pilot-operated self-propelled fluid relief valve according to claim 1, characterized in that: The relief valve is suitable for starting control of a liquid rocket engine, and the working medium is high-pressure gas, liquid oxygen, kerosene or nitrogen.

10. A control method for a pilot-operated self-driven fluid relief valve according to any one of claims 1 to 9, characterized in that The specific steps are as follows: Opening control stage: control gas is introduced into the pilot valve air control port (208), driving the pilot valve piston (202) to overcome the elastic force of the pilot valve spring (205) and move in the direction of the pilot valve cover (203), opening the pilot valve inlet (210) and closing the pilot valve pressure relief port (209), so that the high-pressure medium in the first flow chamber (115) of the main valve flows into the main valve pressure chamber (118) through the pilot valve outlet channel (213); Self-driven main valve opening stage: After the pressure of the main valve pressure chamber (118) and the first flow chamber (115) is balanced, the main valve core (103) is driven to move in the opening direction by utilizing the pressure difference that the effective pressure-bearing area of ​​the main valve piston (106) is larger than the effective pressure-bearing area of ​​the main valve core (103), thereby connecting the main valve inlet (114) and the main valve outlet (119); Closing control stage: the control gas of the pilot valve air control port (208) is cut off, the pilot valve spring (205) pushes the pilot valve piston (202) to reset and close the pilot valve inlet (210) and open the pilot valve pressure relief port (209), and the medium in the main valve pressure chamber (118) is discharged to atmospheric pressure through the pilot valve piston pressure relief channel (211); Self-driven closing of the main valve stage: After the main valve pressure chamber (118) is depressurized, the main valve core (103) is reset under the action of the elastic force of the main valve spring (105) and the pressure difference of the medium, cutting off the communication between the main valve inlet (114) and the main valve outlet (119).

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