An open gas control system for cryogenic liquid rocket engines

Abstract

This invention discloses an open pneumatic control system for cryogenic liquid rocket engines, belonging to the field of liquid rocket engine design. Compared to traditional closed pneumatic control systems, this invention eliminates the valve assembly box and replaces the control solenoid valve with a new type of solenoid valve with anti-backflow function, and replaces the pneumatic valve with an anti-backflow pneumatic valve. Eliminating the valve box also eliminates the need for the valve box cable, requiring only one control cable, reducing electrical interfaces and improving the reliability of electrical products. In the original closed system, fault isolation between solenoid valves was not possible; this invention, by eliminating the valve box, eliminates mutual interference between controlled valves, achieving fault isolation. The solenoid valve layout of this invention is more flexible, has higher structural reliability, facilitates fault isolation, improves functional reliability, and simultaneously reduces engine weight.

Description

Technical Field

[0001] This invention relates to an open gas control system for cryogenic liquid rocket engines, and more particularly to an open gas control system for cryogenic controlled valves of liquid rocket engines using a novel anti-backflow solenoid valve, belonging to the field of liquid rocket engine design. Background Technology

[0002] Cryogenic liquid rocket engines (hereinafter referred to as "engines") are divided into several subsystems according to their functions, including gas control system, purging system, propellant supply system, and combustion device.

[0003] The pneumatic control system in the engine is responsible for controlling the opening and closing of various pneumatic valves and guiding the flow of control air. It typically consists of components such as a control gas cylinder, a pressure reducing valve, a valve assembly box (containing a control solenoid valve), the controlled valves, and control cables.

[0004] A pneumatic control system that places the control solenoid valves inside the valve assembly box can be called a closed pneumatic control system. It installs all control solenoid valves inside the valve assembly box to prevent "cold suction" from occurring at the solenoid valve exhaust port. This is a common practice for cryogenic engines both domestically and internationally.

[0005] To facilitate venting of cryogenic controlled valves, an vent is typically installed on the solenoid valve. After the solenoid valve closes, the helium gas inside the cryogenic valve's control chamber is released through this vent. However, if the solenoid valve is directly exposed to the atmosphere, humid air can enter the control chamber through the solenoid valve's vent, causing moisture absorption and freezing, forming solid water, solid oxygen, or solid nitrogen. This is known as "cold absorption." "Cold absorption" can cause the controlled valve to "freeze," become stuck, and fail to perform its opening and closing function. It can even lead to deflagration of solid oxygen, posing a safety risk.

[0006] All control solenoid valves are placed in a sealed valve assembly box, and a check valve is installed on the valve assembly box. When the pressure exceeds a certain positive pressure (generally slightly higher than the ambient atmospheric pressure), the check valve opens to prevent overpressure inside the box.

[0007] When the solenoid valve is energized, the control gas (usually helium) enters the control chamber of the controlled valve through the solenoid valve; when the solenoid valve is de-energized, the helium in the control chamber of the controlled valve is discharged into the valve box through the solenoid valve exhaust port. The box maintains a certain positive pressure, so that the cryogenic control chamber and the solenoid valve are in a helium atmosphere, eliminating the possibility of "cold absorption" in the control chamber.

[0008] While this type of closed-loop pneumatic control system can prevent "cold suction," it is prone to drawbacks such as insufficient reliability, excessive weight, and limited solenoid valve layout. Summary of the Invention

[0009] The technical problem solved by this invention is to overcome the shortcomings of existing closed gas control systems for cryogenic liquid rocket engines and provide an open gas control system for cryogenic liquid rocket engines. This system features a more flexible solenoid valve layout, higher structural reliability, easier fault isolation, improved functional reliability, and reduced engine weight.

[0010] The technical solution of this invention is:

[0011] An open gas control system for cryogenic liquid rocket engines includes a control gas cylinder, a manual switch, a pressure reducing valve, a control cable, connecting pipes, an anti-backflow solenoid valve, and an anti-backflow pneumatic valve.

[0012] The outlet of the control cylinder is connected to the inlet of the pressure reducing valve via a manual switch, and the outlet of the pressure reducing valve is connected to the engine isolation chamber via a connecting pipe; several single-chamber control circuits and dual-chamber control circuits are connected in parallel on the bypass passage of the connecting pipe.

[0013] The single-chamber control circuit includes an anti-backflow solenoid valve, a control conduit, and a single-chamber controlled valve. The inlet of the anti-backflow solenoid valve is connected to the bypass passage of the connecting pipeline, and the outlet of the anti-backflow solenoid valve is connected to the control chamber of the single-chamber controlled valve through the control conduit.

[0014] The dual-chamber control circuit includes an anti-backflow pneumatic valve, an anti-backflow solenoid valve, a control conduit, and a dual-chamber controlled valve. The inlet of the anti-backflow pneumatic valve and the inlet of the anti-backflow solenoid valve are both connected to the bypass passage of the connecting pipeline. The first outlet of the anti-backflow pneumatic valve is connected to the closing control chamber of the dual-chamber controlled valve through the control conduit. The second outlet of the anti-backflow pneumatic valve is connected to the outlet of the anti-backflow solenoid valve. The outlet of the anti-backflow solenoid valve is connected to the opening control chamber of the dual-chamber controlled valve through the control conduit.

[0015] The anti-backflow solenoid valve is connected to the control system via a control cable.

[0016] Preferably, the anti-backflow solenoid valve includes a spring, a lower valve core, a pin, an upper valve core, a push rod, an adjusting screw, an armature, a yoke, a sealing ring, an anti-backflow exhaust assembly, a solenoid valve body, and an inlet nozzle;

[0017] The solenoid valve housing has a lower valve core cavity, an upper valve core cavity, and a through cavity connecting the upper and lower valve core cavities. The through cavity is connected to the solenoid valve outlet. A self-isolating valve inlet is provided on the solenoid valve housing, and the self-isolating valve inlet is connected to the upper valve core cavity. An anti-backflow exhaust assembly is installed at the self-isolating valve inlet of the solenoid valve housing. The lower valve core is installed in the lower valve core cavity with a clearance fit, and a groove is machined at the bottom of the lower valve core, in which a spring is installed. The upper valve core is installed in the upper valve core cavity, and a groove is machined at the top of the upper valve core. A pin is located in the through cavity, connecting the upper and lower valve cores. A sealing ring is provided between the upper valve core and the inner wall of the solenoid valve housing.

[0018] The electromagnet housing is threaded onto the upper part of the solenoid valve housing, the yoke is fixed in the electromagnet housing, and the armature is installed in the groove at the top of the yoke with a clearance fit, and can move axially along the groove at the top of the yoke; the yoke and the armature are machined with a connecting cavity, and the push rod is located in the connecting cavity. One end of the push rod is located in the groove at the top of the upper valve core, and the other end is connected to the adjusting screw, which is threaded to the top of the armature connecting cavity;

[0019] The lower part of the solenoid valve housing is threaded into the inlet nozzle.

[0020] Preferably, the anti-back-suction pneumatic valve is a pneumatically operated pneumatic directional valve equipped with an anti-back-suction exhaust assembly; when the anti-back-suction solenoid valve connected in parallel with it is not energized, the inlet and the first outlet are kept connected; when the anti-back-suction solenoid valve connected in parallel with it is energized, the exhaust assembly of the anti-back-suction pneumatic valve is connected to the first outlet, while the inlet and the first outlet are cut off; when the anti-back-suction solenoid valve connected in parallel with it is closed, the original state is restored.

[0021] Preferably, the anti-backflow exhaust assembly is a valve core.

[0022] Preferably, the anti-backflow exhaust assembly includes a one-way valve housing, a one-way valve core, a one-way valve cover, and a one-way valve spring;

[0023] The one-way valve housing has a through inlet cavity and a valve core cavity machined inside. The one-way valve cover is threaded to the one-way valve housing, and the one-way valve cover has an outlet cavity that communicates with the valve core cavity. The diameter of the valve core cavity is larger than that of the inlet cavity. The one-way valve core is installed in the valve core cavity with a clearance fit.

[0024] The inlet chamber of the anti-backflow solenoid valve is connected to the inlet of the solenoid valve housing from the isolation valve inlet. The one-way valve spring is located in the valve core cavity, with one end abutting against the one-way valve cover. When there is no gas flow at the inlet of the solenoid valve housing from the isolation valve inlet, the other end abuts the one-way valve core against the sealing surface of the inlet chamber.

[0025] The inlet chamber of the anti-backflow pneumatic valve is connected to the inlet of the isolation valve housing. The one-way valve spring is located in the valve core cavity, with one end abutting against the one-way valve cover. When there is no gas flow at the inlet of the isolation valve housing, the other end presses the one-way valve core against the sealing surface of the inlet chamber.

[0026] Preferably, the control gas cylinder is a pressure vessel made of titanium alloy, and the control gas is helium.

[0027] Preferably, the pressure reducing valve is a reverse unloading type pressure reducing valve.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The open pneumatic control system of the present invention eliminates the valve assembly box (hereinafter referred to as the valve box). The solenoid valve, pneumatic valve and exhaust check valve that actually perform the function in the valve assembly box only account for 30% to 50% of the total weight. After replacing them all with anti-back-suction solenoid valves and anti-back-suction pneumatic valves, the weight can be reduced by about 50%.

[0030] (2) The valve assembly box in the original closed system is large in size, requiring a large installation space to be reserved in the engine. Using the open pneumatic control system of this invention is beneficial to the overall engine layout, and the solenoid valves and pneumatic valves can be installed in combination or separately.

[0031] (3) After the valve box is removed, the valve box cable can be removed simultaneously. Only one control cable needs to be retained, reducing electrical interfaces and improving the reliability of electrical products.

[0032] (4) In the original closed system, the solenoid valve was installed vertically in the valve box with the solenoid valve inlet as the base, which resulted in a large cantilever. After the improvement, all solenoid valves and pneumatic valves are installed "flat" on the engine, eliminating the cantilever structure and increasing structural reliability.

[0033] (5) In the original closed system, fault isolation could not be achieved between solenoid valves. For example, if the bellows of the liquid oxygen valve was damaged, liquid oxygen might enter the valve box, thereby freezing the control chamber of the liquid hydrogen valve. After the improvement, the valve box was eliminated, and there was no mutual influence between the controlled valves, thus achieving fault isolation.

[0034] (6) This invention improves the reliability of the exhaust function. Existing exhaust check valves suffer from a "single-point failure" problem; if the check valve in the valve box fails, all controlled valves within the valve box lose protection. Assuming the original valve box design uses 7 solenoid valves sharing 2 exhaust check valves, and each solenoid valve operates 20 times within the task profile, the 2 exhaust check valves would need to operate 140 times. Assuming the reliability of each exhaust check valve is 0.99, the probability of both exhaust check valves operating reliably is 0.98. With the open pneumatic control system, taking a Weibull distribution shape parameter of 3 and a confidence level of 0.7 as an example, the reliability of a single solenoid valve exhaust port operating 20 times increases to 0.99997, and the probability of all 7 exhaust ports operating reliably simultaneously is 0.9998. The exhaust port reliability is significantly higher than the original design. Attached Figure Description

[0035] Figure 1 This invention provides a diagram of an open gas control system for a cryogenic liquid rocket engine;

[0036] Figure 2 A schematic diagram of the principle of a novel anti-backflow solenoid valve in an open pneumatic control system;

[0037] Figure 3 Schematic diagrams of two possible solutions for preventing reverse suction exhaust components;

[0038] Figure 4 This is a schematic diagram of a traditional closed-loop pneumatic control system. The dashed lines represent components unique to the closed-loop system. Detailed Implementation

[0039] The open-type gas control system of this invention is applied to cryogenic liquid rocket engines. The system consists of components such as control gas cylinders, manual switches, pressure reducing valves, anti-backflow solenoid valves, anti-backflow pneumatic valves, control cables, and related connecting pipelines.

[0040] like Figure 1 As shown, the outlet of control cylinder 01 is connected to the inlet of pressure reducing valve 09 via manual switch 010. The outlet of pressure reducing valve is connected to the engine isolation chamber via a connecting pipe. Several single-chamber control circuits and dual-chamber control circuits are connected in parallel on the bypass path of the connecting pipe. The single-chamber control circuit includes an anti-backflow solenoid valve, a control conduit, and a single-chamber controlled valve. The inlet of anti-backflow solenoid valve 05 is connected to the bypass path of the connecting pipe, and the outlet of anti-backflow solenoid valve is connected to the control chamber of the single-chamber controlled valve via a control conduit. The dual-chamber control circuit includes an anti-backflow pneumatic valve 04, an anti-backflow solenoid valve, a control conduit, and a dual-chamber controlled valve. The inlet of the anti-backflow pneumatic valve and the inlet of the anti-backflow solenoid valve are both connected to the bypass path of the connecting pipe. The first outlet of the anti-backflow pneumatic valve is connected to the closing control chamber of the dual-chamber controlled valve via a control conduit. The second outlet of the anti-backflow pneumatic valve is connected to the outlet of the backflow solenoid valve. The outlet of the backflow solenoid valve is connected to the opening control chamber of the dual-chamber controlled valve via a control conduit. The anti-backflow solenoid valve is connected to the control system via a control cable.

[0041] like Figure 2As shown, the anti-backflow solenoid valve includes a spring 1, a lower valve core 2, a pin 3, an upper valve core 4, a push rod 5, an adjusting screw 6, an armature 7, a yoke 8, a sealing ring 10, an anti-backflow exhaust assembly 11, a solenoid valve housing 12, and an inlet nozzle 13. The solenoid valve housing 12 has a lower valve core cavity, an upper valve core cavity, and a through cavity connecting the upper and lower valve core cavities. The through cavity is connected to the solenoid valve outlet. A self-isolating valve inlet is provided on the solenoid valve housing, which is connected to the upper valve core cavity. The anti-backflow exhaust assembly is installed at the self-isolating valve inlet of the solenoid valve housing 12. The lower valve core 2 is installed in the lower valve core cavity with a clearance fit, and a groove is machined at the bottom of the lower valve core; the spring 1 is installed in the groove. The upper valve core 4 is installed in the upper valve core cavity, and a groove is machined at the top of the upper valve core. The pin is located in the through cavity and connects the upper and lower valve cores. A sealing ring is provided between the upper valve core and the inner wall of the solenoid valve housing. The electromagnet housing is threaded onto the upper part of the solenoid valve housing 12. The yoke 8 is fixed in the electromagnet housing. The armature 7 is installed in the top groove of the yoke 8 with a clearance fit, and can move axially along the top groove of the yoke 8. A connecting cavity is machined in the yoke 8 and the armature 7. The push rod 5 is located in the connecting cavity. One end of the push rod 5 is located in the top groove of the upper valve core, and the other end is connected to the adjusting screw 6. The adjusting screw 6 is threaded to the top of the connecting cavity of the armature 7. The lower part of the solenoid valve housing 12 is threaded into the inlet nozzle. Figure 2 9 is the control cable interface.

[0042] like Figure 3 As shown, the anti-backdraft exhaust assembly is a valve core or a self-isolating check valve solution. In the self-isolating check valve solution, the anti-backdraft exhaust assembly includes a check valve housing 104, a check valve core 103, a check valve cover 101, and a check valve spring 102. The check valve housing 104 has a through inlet chamber and a valve core chamber machined inside. The check valve cover 101 is threaded to the check valve housing 104, and the check valve cover 101 has an outlet chamber machined inside, which communicates with the valve core chamber. The inlet chamber communicates with the self-isolating valve inlet of the solenoid valve housing. The diameter of the valve core chamber is larger than that of the inlet chamber. The check valve core 103 is installed in the valve core chamber with a clearance fit. The check valve spring 102 is located in the valve core chamber, with one end abutting against the check valve cover 101. When there is no gas flow at the self-isolating valve inlet of the solenoid valve housing, the other end abuts the check valve core 103 against the sealing surface of the inlet chamber.

[0043] The anti-back-suction pneumatic valve is a pneumatically operated directional valve equipped with an anti-back-suction exhaust assembly. When the anti-back-suction solenoid valve connected in parallel is not energized, the inlet remains connected to the first outlet. When the anti-back-suction solenoid valve connected in parallel is energized, the anti-back-suction exhaust assembly of the anti-back-suction pneumatic valve connects to the first outlet, while the inlet and first outlet are disconnected. When the anti-back-suction solenoid valve connected in parallel is closed, the valve returns to its original state. The anti-back-suction exhaust assembly of the anti-back-suction pneumatic valve has the same structure and principle as that of the anti-back-suction solenoid valve.

[0044] In this invention, the control gas cylinder is a pressure vessel, typically made of high-strength, lightweight materials such as titanium alloy, and the control gas is generally helium. The volume and operating pressure of the control gas cylinder can be dynamically adjusted according to the engine's gas supply requirements.

[0045] A manual switch is a type of manual valve, which can also be an electromagnetic, electric, or electro-explosive valve. It is used to control the isolation between the gas cylinder and the pressure reducing valve before the engine starts.

[0046] Pressure reducing valves are generally reverse unloading type pressure reducing valves. Their function is to reduce the high-pressure helium gas supplied by the control cylinder to the required pressure, so as to provide constant pressure control gas for the engine.

[0047] The control cable is used to control the anti-backflow solenoid valve switch. Its upstream is the engine main socket, which connects to the control cable on the arrow. Its downstream extends into N branches (N = the number of anti-backflow solenoid valves controlled), and the branch cables are connected to each anti-backflow solenoid valve respectively.

[0048] The anti-backflow control solenoid valve (hereinafter referred to as the anti-backflow solenoid valve) is a key component of this open pneumatic control system. The anti-backflow solenoid valve is a direct-acting solenoid valve. When the coil is energized, the electromagnet generates an attractive force, pushing the push rod downwards. This causes the upper valve core to contact and seal with the valve seat, closing the inlet of the anti-backflow exhaust assembly and the solenoid valve outlet channel. The lower valve core disengages from the valve seat, and the solenoid valve inlet and outlet are connected, allowing control gas to flow from the inlet to the outlet, filling the control chamber of the controlled valve. When the coil is de-energized, the attractive force disappears, and the spring force resets the upper and lower valve cores, closing the solenoid valve inlet and outlet channels. The outlet then reconnects with the inlet of the anti-backflow exhaust assembly, and the control gas in the control chamber of the controlled valve is discharged from the anti-backflow exhaust assembly.

[0049] The original assembly position is: under the action of spring force, the lower valve core is normally closed, the upper valve core is normally open, and the outlet is connected to the inlet of the anti-backflow exhaust assembly.

[0050] The upper valve core sealing surface is designed as a "convex" structure, leaving part of the cavity for machining the exhaust channel.

[0051] An O-ring seal is added between the upper valve core and the housing, designed with a small sealing pressure to minimize resistance to the solenoid valve's operation, as long as positive pressure protection can be achieved.

[0052] The anti-backflow exhaust assembly uses either a one-way valve or a valve core. The valve core is a widely used one-way exhaust device, consisting of a cylindrical body that is hollow at one end and closed at the other. One or more small holes on the side connect to the hollow part, and a rubber tube is fitted over these holes. When compressed air enters from the hollow end, it pushes up the elastic rubber tube, opening the seal and preventing reverse airflow. The one-way valve maintains a one-way seal using spring force. It opens when the inlet pressure reaches a certain value, providing good sealing and reliability.

[0053] Different solutions can be selected based on the anti-backflow requirements. For example, when the controlled valve is a liquid oxygen or liquid methane valve, its operating temperature is higher than that of liquid nitrogen, and there is no risk of solid cavitation. A valve core solution can be used to reduce the weight of the solenoid valve. However, for liquid hydrogen valves, the medium temperature is lower than that of liquid nitrogen, and not only moisture protection but also air protection is required. A one-way valve solution with better sealing performance can be used.

[0054] The operating mode of the open-type pneumatic control system formed by the above components is as follows:

[0055] When the engine is running, the controlled valves must operate in a specific sequence. When a controlled valve needs to be activated, the manual switch is in the open position, and control air is available at the inlet of the solenoid valve. At this time, the control power supply is energized to open the corresponding solenoid valve, and the control air enters the control chamber of the controlled valve, causing the passive valve to activate.

[0056] When the controlled valve finishes its operation, the solenoid valve is de-energized and closed, the controlled valve's control chamber releases air through the solenoid valve's exhaust port, and the controlled valve resets.

[0057] After the solenoid valve is de-energized, the outlet of the solenoid valve is connected to the inlet of the anti-backflow exhaust assembly, and the control gas remaining between the outlet of the solenoid valve and the control chamber of the controlled valve is discharged from the inlet of the anti-backflow exhaust assembly.

[0058] Some controlled valves are equipped with two control chambers: an open chamber and a closed chamber. They use anti-back-suction pneumatic valves in conjunction with anti-back-suction solenoid valves. When the corresponding solenoid valve is not energized, control air is supplied to the closed chamber, and the inlet of the open chamber is the same as that of the anti-back-suction exhaust component of the solenoid valve. When the corresponding solenoid valve is energized, the pneumatic valve closes, and the closed chamber releases air through the inlet of the anti-back-suction exhaust component of the pneumatic valve. The open chamber supplies control air through the inlet of the solenoid valve.

[0059] like Figure 1 As shown, when the pneumatic control system is not working, the manual switch 010 is in the closed state, and the control gas in the control gas cylinder 01 is cut off. When the pneumatic control system is working, the manual switch 010 must be opened first to fill the solenoid valve 05 with control gas. At this time, the inlet and outlet of the pneumatic valve 04 are connected, and the control gas flows into the hydrogen bypass valve and the bypass valve closing chamber.

[0060] According to the timing requirements, the hydrogen bypass valve needs to be opened. At this time, the corresponding solenoid valve is energized, and control gas enters the open chamber of the hydrogen bypass valve. The corresponding pneumatic valve closes, and the remaining control gas in the hydrogen bypass valve's closed chamber guide tube is discharged from the inlet of the pneumatic valve's anti-backflow exhaust assembly.

[0061] According to the timing requirements, the hydrogen bypass valve needs to be closed. At this time, the solenoid valve corresponding to the open chamber is de-energized, and the residual control gas in the hydrogen bypass open chamber conduit is discharged from the inlet of the solenoid valve's anti-backflow exhaust assembly. The corresponding pneumatic valve opens, and the control gas for the closed chamber re-enters the closed chamber, reliably closing the hydrogen bypass valve.

[0062] According to the timing requirements, the oxygen release valve needs to be opened. At this time, the corresponding solenoid valve is energized, and control gas enters the oxygen release valve opening chamber.

[0063] According to the timing requirements, the oxygen release valve needs to be closed. At this time, the corresponding solenoid valve is de-energized, and the remaining control gas in the oxygen release valve's open-chamber conduit is discharged from the inlet of the solenoid valve's anti-backflow exhaust assembly. The oxygen release valve core is then returned to the closed position by spring force.

[0064] The operating mode of the controlled valve that requires both a pneumatic valve and a solenoid valve is the same as that of the hydrogen bypass valve. The operating mode of the controlled valve that only requires solenoid valve control is the same as that of the oxygen vent valve.

[0065] like Figure 4 The diagram shown is a schematic of a closed-loop pneumatic control system. Figure 4 In the diagram, 02 is the valve assembly box on one side, 08 is the valve assembly box on the other side, 03 is the exhaust check valve, 06 is the valve box cable, and 07 is the original control cable.

[0066] and Figure 4 Unlike the closed-loop pneumatic control system, the open-loop pneumatic control system eliminates the valve box in the valve assembly box 02, eliminates the exhaust check valve 03 on the valve box, eliminates the control cable 07 and one valve box cable, adds a branch of the valve box cable 06, and replaces the main plug with a single main control cable.

[0067] This invention replaces the non-moisture-proof solenoid valve at the ordinary exhaust port of a closed pneumatic control system with a solenoid valve that has an anti-backflow function, and replaces the ordinary pneumatic valve with a pneumatic valve that has an anti-backflow function.

[0068] like Figure 2As shown, in the assembly position, due to the spring force of spring 1, the lower valve core 2 and the solenoid valve housing 12 form a tight fit, isolating the inlet and outlet channels of the solenoid valve. In the assembly position, the lower valve core 2 pushes up the upper valve core 4 through pin 3, maintaining a certain gap between the upper valve core 4 and the solenoid valve housing 12. At this time, the outlet of the solenoid valve is connected to the inlet of the anti-back-suction exhaust assembly. When the electromagnet is energized, magnetic flux is generated in the magnetic conductor, causing the yoke 8 and armature 7 to attract each other, moving the armature 7 towards the yoke 8. When the electromagnet is energized and the armature 7 moves towards the yoke 8, it drives the push rod 5 and the entire transmission path downwards. The transmission path is: armature 7 → push rod 5 → upper valve core 4 → pin 3 → lower valve core 2 → spring 1 compression. After the transmission path is completed when the electromagnet is energized, the upper valve core 4 and the solenoid valve housing 12 form a tight fit, isolating the outlet of the solenoid valve from the inlet of the anti-back-suction exhaust assembly. A certain gap exists between the lower valve core 2 and the solenoid valve housing 12, allowing control air to flow from the inlet into the solenoid valve outlet. When the electromagnet is de-energized, the solenoid valve returns to its assembled position under the force of spring 1. The adjusting screw 6 adjusts the clearance between the armature 7 and the yoke 8; it is threadedly fitted to the armature 7. The sealing ring 10 ensures a seal between the upper valve core 4 and the solenoid valve housing 12. It is designed with a small sealing pressure to minimize resistance to the solenoid valve's operation, only requiring positive pressure protection. This seal prevents moisture from being drawn into the control chamber of the controlled valve from the mounting surface A.

[0069] The anti-backdraft exhaust assembly of the anti-backdraft pneumatic valve of this invention has the same structure as that of the anti-backdraft solenoid valve, both including two schemes: a valve core scheme and a one-way valve scheme. The valve core is also a simple one-way valve structure, which is a universal device. The valve core and the one-way valve are integrated into the solenoid valve housing according to the solenoid valve structure to achieve structural compatibility. The one-way valve consists of a one-way valve housing 104, a one-way valve core 103, a one-way valve cover 101, a one-way valve spring 102, etc. Figure 3 As shown, the check valve is a normally closed valve. When the pressure inside the solenoid valve (pneumatic valve) is lower than the opening pressure, the valve core 103 and the check valve body 104 are tightly fitted by the spring force of the check valve spring 102, and the check valve is in the closed state, maintaining a certain positive pressure inside the solenoid valve (pneumatic valve). When the pressure inside the solenoid valve (pneumatic valve) is greater than the opening pressure, the medium force overcomes the spring force and opens the valve core, allowing the solenoid valve (pneumatic valve) to release exhaust gas through the check valve.

[0070] Compared to traditional solutions, the biggest difference in the open-type gas control system is the elimination of the valve assembly box and the replacement of the control solenoid valve with a new type of solenoid valve with anti-backflow function. The anti-backflow function refers to the solenoid valve's ability to prevent humid air from entering the cryogenic valve control chamber. This invention improves the technical level of my country's liquid rocket engines without increasing the complexity of the manufacturing process.

[0071] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. An open gas control system for cryogenic liquid rocket engines, characterized in that: This includes control cylinders, manual switches, pressure reducing valves, control cables, connecting pipes, anti-backflow solenoid valves, and anti-backflow pneumatic valves; The outlet of the control cylinder is connected to the inlet of the pressure reducing valve via a manual switch, and the outlet of the pressure reducing valve is connected to the engine isolation chamber via a connecting pipe; several single-chamber control circuits and dual-chamber control circuits are connected in parallel on the bypass passage of the connecting pipe. The single-chamber control circuit includes an anti-backflow solenoid valve, a control conduit, and a single-chamber controlled valve. The inlet of the anti-backflow solenoid valve is connected to the bypass passage of the connecting pipeline, and the outlet of the anti-backflow solenoid valve is connected to the control chamber of the single-chamber controlled valve through the control conduit. The dual-chamber control circuit includes an anti-backflow pneumatic valve, an anti-backflow solenoid valve, a control conduit, and a dual-chamber controlled valve. The inlet of the anti-backflow pneumatic valve and the inlet of the anti-backflow solenoid valve are both connected to the bypass passage of the connecting pipeline. The first outlet of the anti-backflow pneumatic valve is connected to the closing control chamber of the dual-chamber controlled valve through the control conduit. The second outlet of the anti-backflow pneumatic valve is connected to the outlet of the anti-backflow solenoid valve. The outlet of the anti-backflow solenoid valve is connected to the opening control chamber of the dual-chamber controlled valve through the control conduit. The anti-backflow solenoid valve is connected to the control system via a control cable; The anti-backflow solenoid valve includes a spring (1), a lower valve core (2), a pin (3), an upper valve core (4), a push rod (5), an adjusting screw (6), an armature (7), a yoke (8), a sealing ring (10), an anti-backflow exhaust assembly (11), a solenoid valve housing (12), and an inlet nozzle (13). The solenoid valve housing is provided with a self-isolation valve inlet, and the anti-backflow exhaust assembly is installed at the self-isolation valve inlet of the solenoid valve housing (12).

2. The open gas control system for cryogenic liquid rocket engines according to claim 1, characterized in that: The solenoid valve housing (12) is internally designed with a lower valve core cavity, an upper valve core cavity, and a through cavity connecting the upper and lower valve core cavities. The through cavity is connected to the solenoid valve outlet, and the self-isolating valve inlet is connected to the upper valve core cavity. The lower valve core (2) is installed in the lower valve core cavity with a clearance fit. A groove is machined at the bottom of the lower valve core, and the spring 1 is installed in the groove. The upper valve core (4) is installed in the upper valve core cavity. A groove is machined at the top of the upper valve core. A pin is located in the through cavity and connects the upper and lower valve cores. A sealing ring is provided between the upper valve core and the inner wall of the solenoid valve housing. The electromagnet housing is threaded onto the upper part of the solenoid valve housing (12), the yoke (8) is fixed in the electromagnet housing, and the armature (7) is installed in the top groove of the yoke (8) with a clearance fit, and can move axially along the top groove of the yoke (8); the yoke (8) and the armature (7) are machined with a connecting cavity, and the push rod (5) is located in the connecting cavity. One end of the push rod (5) is located in the top groove of the upper valve core, and the other end is connected to the adjusting screw (6). The adjusting screw (6) is threaded to the top of the connecting cavity of the armature (7); The lower part of the solenoid valve housing (12) is threaded into the inlet nozzle.

3. The open gas control system for cryogenic liquid rocket engines according to claim 1, characterized in that: The anti-backflow pneumatic valve is a pneumatically operated directional valve equipped with an anti-backflow exhaust assembly. When the anti-backflow solenoid valve connected in parallel with it is not energized, the inlet and the first outlet remain connected. When the anti-backflow solenoid valve connected in parallel with it is energized, the exhaust assembly of the anti-backflow pneumatic valve is connected to the first outlet, while the inlet and the first outlet are disconnected. When the anti-backflow solenoid valve connected in parallel with it is closed, it returns to its original state.

4. An open gas control system for cryogenic liquid rocket engines according to claim 2 or 3, characterized in that: The anti-backflow exhaust assembly is a valve core.

5. An open gas control system for cryogenic liquid rocket engines according to claim 2 or 3, characterized in that: The anti-backflow exhaust assembly includes a one-way valve housing, a one-way valve core, a one-way valve cover, and a one-way valve spring; The one-way valve housing has a through inlet cavity and a valve core cavity machined inside. The one-way valve cover is threaded to the one-way valve housing, and the one-way valve cover has an outlet cavity that communicates with the valve core cavity. The diameter of the valve core cavity is larger than that of the inlet cavity. The one-way valve core is installed in the valve core cavity with a clearance fit. The inlet chamber of the anti-backflow solenoid valve is connected to the inlet of the solenoid valve housing from the isolation valve inlet. The one-way valve spring is located in the valve core cavity, with one end abutting against the one-way valve cover. When there is no gas flow at the inlet of the solenoid valve housing from the isolation valve inlet, the other end abuts the one-way valve core against the sealing surface of the inlet chamber. The inlet chamber of the anti-backflow pneumatic valve is connected to the inlet of the isolation valve housing. The one-way valve spring is located in the valve core cavity, with one end abutting against the one-way valve cover. When there is no gas flow at the inlet of the isolation valve housing, the other end presses the one-way valve core against the sealing surface of the inlet chamber.

6. An open gas control system for cryogenic liquid rocket engines according to claim 1, characterized in that: The control gas cylinder is a pressure vessel made of titanium alloy, and the control gas is helium.

7. An open gas control system for cryogenic liquid rocket engines according to claim 1, characterized in that: The pressure reducing valve is a reverse unloading type pressure reducing valve.

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