A tank test buffer system and method

Abstract

This invention discloses a liquid rocket engine propellant tank test buffer system and process method, including a safety valve, regulating valve, shut-off valve, buffer container, differential pressure transmitter, pressure control and display system, filter, etc. The propellant tank test buffer system supplies gas to the system. Three buffer containers are connected in parallel, with regulating and shut-off valves installed at both ends for automatic / manual control of gas filling and emptying. The three inlets of the engine propellant tank are connected to the pipelines of the three buffer containers. Gas filling is performed on the three inlets of the propellant tank through the buffer containers, and the filling rate of the three inlets can be automatically controlled to keep the pressure difference across the diaphragm inside the propellant tank within a controlled range. This invention can simultaneously and uniformly pressurize different cavities of the propellant tank and measure and control the pressure difference between the cavities, ensuring stability during the propellant tank test and avoiding damage to the gas-liquid diaphragm of the propellant tank. It has advantages such as simple structure, easy operation, and strong scalability.

Description

Technical Field

[0001] This invention relates to a test buffer system and method for a propellant tank, belonging to the field of rocket engine manufacturing. Background Technology

[0002] As a crucial component of liquid rocket engines, the performance and reliability of the propellant tank are critical to the engine's success in space missions. The gas-liquid diaphragm within the propellant tank is the key part that separates the gas and liquid chambers and ensures continuous operation. During liquid supply, the pressure in the gas chamber is higher than that in the liquid chamber as liquid is output. Under the pressure difference, the gas-liquid diaphragm deforms, ensuring a continuous and stable liquid output. Therefore, the gas-liquid diaphragm is crucial for stable tank operation. However, the gas-liquid diaphragm is located inside the tank, making it difficult to observe. Its complex structure, typically made of thin metal, makes it prone to deformation and difficult to detect. Therefore, protecting the gas-liquid diaphragm is paramount in various tank tests. Excessive pressure on the diaphragm can cause deformation or even damage, affecting the reliability of the tank structure. Thus, tests such as helium mass spectrometry require simultaneous inflation of both chambers while maintaining the pressure difference across the diaphragm within a controlled range. However, current inflation methods generally suffer from drawbacks such as unmeasurable pressure differences and uncontrollable inflation rates, failing to fully meet the requirements of propellant testing. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a tank test buffer system and method that can pressurize different cavities of the tank and ensure the pressure difference between the cavities. The inflation rate is adjustable and can effectively protect the gas-liquid diaphragm and control the pressure.

[0004] The technical solution adopted in this invention is as follows:

[0005] This invention discloses a test buffer system for a liquid rocket engine propellant tank, comprising regulating valves G2-G7, shut-off valves K1-K9, buffer containers 1-3, differential pressure transmitter P, pressure control and display system S1, filters F1-F3, pipeline inlets and outlets g1-g4, and engine propellant tank C1.

[0006] The buffer containers 1 to 3 are installed in parallel between the inlet of the engine storage tank C1 and the air source. The buffer containers 1 to 3 are equipped with shut-off valves K2 to K7 and regulating valves G2 to G7 at both ends to control the filling and releasing of air in the buffer containers 1 to 3.

[0007] The engine reservoir C1 is divided into a first chamber and a second chamber by a gas-liquid diaphragm. The first chamber is connected to inlet A, and the second chamber is connected to inlet B and inlet C. The gas in the buffer containers 1 to 3 passes through filters F1 to F3 and pipeline outlets g2 to g4 and is then connected to inlets A, B and C to inflate the engine reservoir C1.

[0008] The differential pressure transmitter P is installed between inlet A and inlet B. The differential pressure transmitter P and the pressure control and display system S1 automatically adjust the regulating valves G2 to G7 at both ends of buffer containers 1 to 3, or manually adjust the shut-off valves K2 to K7 at both ends of buffer containers 1 to 3. This allows for the regulation of the charging rate of the three inlets and the chamber pressure of the engine reservoir C1 using a six-level regulation method, ensuring that the pressure difference across the gas-liquid diaphragm of the engine reservoir C1 is always within the control range.

[0009] In the aforementioned buffer system, the six-level adjustment method specifically refers to:

[0010] Open the regulating valves G2 and G3 at both ends of buffer container 1 to enter the first-level speed regulation;

[0011] Close the regulating valves G2 and G3 at both ends of buffer container 1, and open the regulating valves G4 and G5 at both ends of buffer container 2 to enter the secondary speed regulation stage.

[0012] Close the regulating valves G4 and G5 at both ends of buffer container 2, and open the regulating valves G6 and G7 at both ends of buffer container 3 to enter the third-level speed regulation;

[0013] Continue to open the regulating valves G2 and G3 at both ends of buffer container 1 to enter the fourth-level speed regulation;

[0014] Close the regulating valves G2 and G3 at both ends of buffer container 1, and open the regulating valves G4 and G5 at both ends of buffer container 2 to enter the fifth-level speed regulation;

[0015] Open the regulating valves G2 and G3 at both ends of buffer container 1 to enter the sixth-level speed regulation;

[0016] The inflation rate is increased by switching between six speed levels in sequence. When the inflation rate is slowed down, the regulating valve is used first to slow down the inflation rate, and then the previous speed level is switched in sequence to slow down the inflation rate.

[0017] The buffer system described above also includes solenoid valves B1 to B2. Solenoid valve B1 is installed between shut-off valve K1 and shut-off valve K2. Solenoid valve B2 is installed between solenoid valve B1 and the air source.

[0018] In the above buffer system, the capacities of buffer container 1, buffer container 2, and buffer container 3 increase sequentially.

[0019] The buffer system also includes a safety valve A1, which is installed on the gas source interface pipeline. Buffer container 2 is connected in parallel to the side of buffer container 3 away from the gas source, and buffer container 1 is connected in parallel to the side of buffer container 2 away from the gas source.

[0020] In the above buffer system, a shut-off valve K3 and a regulating valve G3 are installed on the side of the buffer container 1 away from the gas source, and a shut-off valve K2 and a regulating valve G2 are installed on the other side; a shut-off valve K5 and a regulating valve G5 are installed on the side of the buffer container 2 away from the gas source, and a shut-off valve K4 and a regulating valve G4 are installed on the other side; a shut-off valve K7 and a regulating valve G7 are installed on the side of the buffer container 3 away from the gas source, and a shut-off valve K6 and a regulating valve G6 are installed on the other side.

[0021] In the above-mentioned buffer system, the side of the shut-off valve K2 away from the buffer container 1 is divided into three paths. The first path is connected to the inlet C via the shut-off valve K8, filter F1 and pipeline outlet g2; the second path is connected to the inlet A via the shut-off valve K1, pressure transmitter P5, filter F2 and pipeline outlet g3; and the third path is connected to the differential pressure transmitter P.

[0022] The aforementioned buffer system also includes pressure transmitters P1 to P7. The differential pressure transmitter P and pressure transmitters P1 to P7 are connected to the pressure control and display system S1 for displaying the pressure of each channel and controlling the differential pressure value.

[0023] In the above-mentioned buffer system, the buffer container 1 is divided into two paths on the side away from the gas source where the shut-off valve K3 and regulating valve G3 are installed. The first path is connected to the inlet B through the pressure transmitter P6, filter F3 and pipeline outlet g4; the second path is connected to the differential pressure transmitter P.

[0024] This invention discloses a test buffering method for a liquid rocket engine propellant tank, characterized in that the tank inflation method includes an automatic control method and a manual control method.

[0025] In the above buffering method, the automatic control method is specifically as follows:

[0026] Open manual shut-off valves K1 and K8, and set the target pressure value of the buffer container, the inflation rate of the buffer container, the target pressure value of the storage tank, the inflation rate of the storage tank, and the differential pressure setting value of the storage tank in the pressure control display system S1.

[0027] The pressure control and display system S1 automatically opens the solenoid valve B2, monitors the pressure values ​​of pressure transmitters P2, P3, and P4, and calculates and automatically controls the opening of regulating valves G2, G4, and G6.

[0028] Based on the target pressure values ​​of buffer containers 1 to 3, the pressure values ​​of buffer containers 1 to 3 are controlled in a closed loop. The pressure control display system S1 automatically closes the regulating valves G2, G4, G6 and the solenoid valve B2, and the inflation is completed.

[0029] The pressure control and display system S1 opens the solenoid valve B1, automatically calls the target pressure value of the storage tank, the storage tank inflation rate, and the storage tank differential pressure set value, and monitors the pressure values ​​of pressure transmitters P5, P6, and P7.

[0030] Based on the rate requirements, a six-level adjustment method for the tank inflation rate is adopted to control the tank inflation rate. When the value of the differential pressure transmitter P is greater than the tank differential pressure value, the opening of regulating valves G2, G4, and G6 is reduced; when the value of the differential pressure transmitter P is less than the tank differential pressure value, the opening of regulating valves G3, G5, and G7 is reduced. The dynamic adjustment control stabilizes the value of the differential pressure transmitter P at the tank differential pressure setpoint.

[0031] In the above buffering method, the manual control method is specifically as follows:

[0032] Open shut-off valves K9, K2, K4, and K6, and close shut-off valves K1, K3, K5, and K7. Connect the air source to the outlet g1 port of the pipeline and pressurize buffer containers 1, 2, and 3 until the pressure transmitters P2, P3, and P4 reach the required pressure values, and then close shut-off valves K2, K4, K6, and K9.

[0033] Open shut-off valves K1, K4, K5, and K8. Slowly increase the pressure on both sides of the gas-liquid diaphragm simultaneously. Observe the pressure control display system S1 to ensure that the pressure difference is within the control range.

[0034] When the pressure in the first chamber connected to inlet A exceeds the target pressure value of the storage tank, adjust the opening of the shut-off valve K1 to keep the pressure difference within the control range; when the pressure in the second chamber connected to inlet B and inlet C exceeds the target pressure value of the storage tank, adjust the opening of the shut-off valve K5 to keep the pressure difference within the control range.

[0035] When the inflation rate is greater than the target inflation rate, close the shut-off valves K4 and K5 and open the shut-off valves K2 and K3 to use the buffer container 1 for inflation.

[0036] When the inflation rate is less than the target inflation rate, close the shut-off valves K4 and K5 and open the shut-off valves K6 and K7 to use the buffer container 3 for inflation, or open the corresponding shut-off valves to combine the buffer containers 1 and 3 into the inflation.

[0037] The advantages of this invention compared to the prior art are:

[0038] 1. The present invention has a simple structure, is easy to manufacture and process, and the components used are easy to replace and find.

[0039] 2. The invention is easy to operate, with simple and clear steps, visible pressure difference, and easy adjustment.

[0040] 3. This invention enables pressurization between different cavities of the same structure with controllable pressure difference, and can be extended to other fields for structural tests of various types and multiple cavities with pressure difference requirements.

[0041] 4. This invention achieves uniform and controllable inflation rate by connecting buffer gas cylinders in parallel, and supports single-cavity or multi-cavity inflation separately or simultaneously. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the test buffer system for the storage tank of the present invention.

[0043] A1-Safety valve, K1-Stop valve, K2-Stop valve, K3-Stop valve, K4-Stop valve, K5-Stop valve, K6-Stop valve, K7-Stop valve, K8-Stop valve, K9-Stop valve, P-Differential pressure transmitter, P1-Pressure transmitter, P2-Pressure transmitter, P3-Pressure transmitter, P4-Pressure transmitter, P5-Pressure transmitter, P6-Pressure transmitter, P7-Pressure transmitter, G2-Control valve, G3-Control valve, G4-Control valve, G5-Control valve, G6-Control valve, G7-Control valve, B1-Solenoid valve, B2-Solenoid valve, F1-Filter, F2-Filter, F3-Filter, g1-Air source interface, g2-Buffer system outlet, g3-Buffer system outlet, g4-Buffer system outlet. Detailed Implementation

[0044] like Figure 1 As shown in the accompanying drawings and embodiments, the present invention will be further described below:

[0045] This invention discloses a test buffer system for a liquid rocket engine propellant tank, comprising: a safety valve A1, regulating valves G2-G7, shut-off valves K1-K7, buffer containers 1-3, a differential pressure transmitter P, a pressure control and display system, filters F1-F3, solenoid valves B1-B2, and pressure transmitters P1-P7; the buffer containers 1-3 are installed in parallel between the engine propellant tank inlet and the gas source, and shut-off valves K2-K7 and regulating valves G2-G7 are installed at both ends of the buffer containers for controlling the charging and discharging of the buffer containers 1-3. The engine propellant tank inlet... Inlet A, inlet B, and inlet C are connected to the outlets g2, g3, and g4 of the three buffer containers 1-3. The buffer containers 1-3 pressurize the storage tank inlets A, B, and C. A differential pressure transmitter P is installed between inlet A and inlet B. The differential pressure transmitter P and the pressure control and display system automatically adjust the regulating valves G2-G7 at both ends of buffer containers 1-3, or manually adjust the shut-off valves K2-K7 at both ends of buffer containers 1-3. A six-stage adjustment method is used to control the pressurization rate of the three inlets of the storage tank, ensuring that the pressure difference across the diaphragm inside the storage tank remains within the control range. Solenoid valve B1 is installed between shut-off valves K1 and K2; solenoid valve B2 is installed between solenoid valve B1 and the air source.

[0046] The capacities of buffer container 1, buffer container 2, and buffer container 3 increase sequentially. In this embodiment, the capacities of buffer container 1, buffer container 2, and buffer container 3 are 10L, 20L, and 30L, respectively.

[0047] A safety valve A1 is installed on the gas source interface pipeline. Buffer container 2 is connected in parallel to the side of buffer container 3 away from the gas source, and buffer container 1 is connected in parallel to the side of buffer container 2 away from the gas source.

[0048] Stop valves K2, K3, G2, and G3 are installed on both sides of buffer container 1, with K3 and G3 installed on the side furthest from the gas source. Stop valves K4, K5, G4, and G5 are installed on both sides of buffer container 2. Stop valves K6, K7, G6, and G7 are installed on both sides of buffer container 3.

[0049] The buffer container 1 is divided into three paths on the side away from the gas source where K2 and G2 are installed. The first path is connected to the inlet C via the shut-off valve K8, filter F1 and pipeline outlet g2; the second path is connected to the inlet A via the shut-off valve K1, pressure transmitter P5, filter F2 and pipeline outlet g3; and the third path is connected to the differential pressure transmitter P.

[0050] The buffer container 1 is divided into two paths on the side away from the gas source, where the shut-off valve K3 and regulating valve G3 are installed. The first path passes through the pressure transmitter P6, filter F3 and pipeline outlet g4 and is connected to the inlet B; the second path is connected to the differential pressure transmitter P.

[0051] The differential pressure transmitter P is installed between the four-way port of the shut-off valve K2 away from the gas source and the filter F3 away from the tank. Differential pressure transmitter P and pressure transmitters P1 through P7 are connected to the pressure control and display system for displaying pressure in each channel and controlling the differential pressure value. Pressure transmitter P1 is connected to the gas source via B2. Pressure transmitters P4, P3, and P2 are respectively placed at the ends of buffers 1, 2, and 3 closest to the gas source. Pressure transmitter P5 is placed between K1 and F2, pressure transmitter P6 is placed between K3 and F3, and pressure transmitter P7 is placed between K8 and F1.

[0052] The tank inflation can be controlled automatically or manually.

[0053] Automatic control mode: Open manual shut-off valves K1 and K8. Set the target pressure value of the buffer container, the inflation rate of the buffer container, the target pressure value of the storage tank, the inflation rate of the storage tank, and the differential pressure setpoint of the storage tank in the program. The program opens solenoid valve B2 and monitors the pressure values ​​of pressure transmitters P2, P3, and P4. It calculates and automatically controls the opening of regulating valves G2, G4, and G6. The closed-loop control adjusts to the inflation pressure value of the buffer container. The program automatically closes regulating valves G2, G4, G6, and solenoid valve B2, and inflation is complete. The program-controlled solenoid valve B1 opens, and the program automatically adjusts... Using the target pressure value of the storage tank, the storage tank inflation rate, and the storage tank differential pressure setpoint, monitor the pressure values ​​of pressure transmitters P5, P6, and P7. Based on the rate requirements, adopt a six-stage speed regulation inflation method to control the storage tank inflation rate. Monitor the value of differential pressure transmitter P. When it is greater than the storage tank differential pressure value, programmable adjustment reduces the opening of regulating valves G2 / G4 / G6. Monitor the value of differential pressure transmitter P. When it is less than the storage tank differential pressure value, programmable adjustment reduces the opening of regulating valves G3 / G5 / G7. Dynamically adjust and control the monitoring to stabilize the value of differential pressure transmitter P at the storage tank differential pressure setpoint.

[0054] Manual control mode: Open shut-off valves K9, K2, K4, and K6, and close shut-off valves K1, K3, K5, and K7. Connect the air source to port g1 and pressurize buffer containers 1, 2, and 3 until pressure transmitters P2, P3, and P4 reach the required pressure values, then close shut-off valves K2, K4, K6, and K9. Open shut-off valves K1, K4, and K5, and slowly increase the pressure on both sides of the gas-liquid diaphragm in the storage tank simultaneously. Observe the pressure control display system to ensure that the pressure difference is within the control range. If the pressure in the storage tank cavity (the cavity connected to inlet A) is too high and exceeds the target pressure value of the storage tank, adjust the shut-off valves. The opening of stop valve K1 is adjusted to keep the pressure difference within the control range. When the pressure in the storage tank cavity (the cavity connected to inlet B and inlet C) is too high and exceeds the target pressure value of the storage tank, the opening of stop valve K5 is adjusted to keep the pressure difference within the control range. When the inflation rate is greater than the target inflation rate, stop valves K4 and K5 are closed and stop valves K2 and K3 are opened to use buffer container 1 for inflation. When the inflation rate is less than the target inflation rate, stop valves K4 and K5 are closed and stop valves K6 and K7 are opened to use buffer container 3 for inflation, or the corresponding stop valves are opened to combine buffer container 1 and buffer container 3 for inflation.

[0055] The six-level adjustment method for the tank inflation rate is as follows:

[0056] In automatic control mode, the program automatically controls and adjusts the regulating valves G2 to G7. The specific steps are as follows:

[0057] Open the regulating valves G2 and G3 at both ends of buffer container 1 to enter the first-level speed regulation;

[0058] Close the regulating valves G2 and G3 at both ends of buffer container 1, and open the regulating valves G4 and G5 at both ends of buffer container 2 to enter the secondary speed regulation stage.

[0059] Close the regulating valves G4 and G5 at both ends of buffer container 2, and open the regulating valves G6 and G7 at both ends of buffer container 3 to enter the third-level speed regulation;

[0060] Continue to open the regulating valves G2 and G3 at both ends of buffer container 1 to enter the fourth-level speed regulation;

[0061] Close the regulating valves G2 and G3 at both ends of buffer container 1, and open the regulating valves G4 and G5 at both ends of buffer container 2 to enter the fifth-level speed regulation;

[0062] Open the regulating valves G2 and G3 at both ends of buffer container 1 to enter the sixth-level speed regulation;

[0063] The inflation rate is increased by switching between six speed levels in sequence. When the inflation rate is slowed down, the regulating valve is used first to slow down the inflation rate, and then the previous speed level is switched in sequence to slow down the inflation rate.

[0064] There are two modes for manual control:

[0065] Method 1 involves manual setting and program control to regulate valves G2 to G7. The specific steps are as follows:

[0066] Open the regulating valves G2 and G3 at both ends of buffer container 1 to enter the first-level speed regulation;

[0067] Close the regulating valves G2 and G3 at both ends of buffer container 1, and open the regulating valves G4 and G5 at both ends of buffer container 2 to enter the secondary speed regulation stage.

[0068] Close the regulating valves G4 and G5 at both ends of buffer container 2, and open the regulating valves G6 and G7 at both ends of buffer container 3 to enter the third-level speed regulation;

[0069] Continue to open the regulating valves G2 and G3 at both ends of buffer container 1 to enter the fourth-level speed regulation;

[0070] Close the regulating valves G2 and G3 at both ends of buffer container 1, and open the regulating valves G4 and G5 at both ends of buffer container 2 to enter the fifth-level speed regulation;

[0071] Open the regulating valves G2 and G3 at both ends of buffer container 1 to enter the sixth-level speed regulation;

[0072] The inflation rate is increased by switching between six speed levels in sequence. When the inflation rate is slowed down, the regulating valve is used first to slow down the inflation rate, and then the previous speed level is switched in sequence to slow down the inflation rate.

[0073] Method 2 involves manually controlling the opening of shut-off valves K2 to K7. The specific steps are as follows:

[0074] Open the shut-off valves K2 and K3 at both ends of buffer container 1 to enter the first-level speed regulation;

[0075] Close the shut-off valves K2 and K3 at both ends of buffer container 1, and open the shut-off valves K4 and K5 at both ends of buffer container 2 to enter the secondary speed regulation stage.

[0076] Close the shut-off valves K4 and K5 at both ends of buffer container 2, and open the shut-off valves K6 and K7 at both ends of buffer container 3 to enter the third-level speed regulation;

[0077] Continue to open the shut-off valves K2 and K3 at both ends of buffer container 1 to enter the fourth-level speed regulation;

[0078] Close the shut-off valves K2 and K3 at both ends of buffer container 1, and open the shut-off valves K4 and K5 at both ends of buffer container 2 to enter the fifth-level speed regulation;

[0079] Open the shut-off valves K2 and K3 at both ends of buffer container 1 to enter the sixth-level speed regulation;

[0080] The inflation rate is increased by switching between six speed levels in sequence. When the inflation rate is slowed down, the stop valve is used first, and then the speed is switched to the previous level in sequence.

[0081] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A test buffer system for a liquid rocket engine propellant tank, characterized in that: This includes regulating valves G2~G7, shut-off valves K1~K9, buffer containers 1~3, differential pressure transmitter P, pressure control and display system S1, filters F1~F3, pipeline inlets and outlets g1~g4, and engine storage tank C1; among which, The buffer containers 1 to 3 are installed in parallel between the inlet of the engine storage tank C1 and the air source. Each of the buffer containers 1 to 3 is equipped with a shut-off valve and a regulating valve at both ends to control the filling and releasing of the buffer containers 1 to 3. The engine storage tank C1 is divided into a first chamber and a second chamber by a gas-liquid diaphragm. The first chamber is connected to inlet A and inlet C, and the second chamber is connected to inlet B. The gas in the buffer containers 1-3 passes through filters F1-F3 and pipeline outlets g2-g4 and is then connected to inlets A, B and C to inflate the engine storage tank C1. The differential pressure transmitter P is installed between inlet A, inlet C and inlet B. The differential pressure transmitter P and the pressure control and display system S1 automatically adjust the regulating valves G2 to G7 at both ends of buffer containers 1 to 3 or manually adjust the shut-off valves K2 to K7 at both ends of buffer containers 1 to 3 to achieve the six-level regulation of the charging rate of the three inlets of engine tank C1 and the chamber pressure, so that the pressure difference between the two ends of the gas-liquid diaphragm of engine tank C1 is always within the control range. The side of the shut-off valve K2 away from the buffer container 1 is divided into three paths. The first path is connected to the inlet C via the shut-off valve K8, filter F1, and pipeline outlet g2. The second path is connected to the inlet A via the shut-off valve K1, pressure transmitter P5, filter F2, and pipeline outlet g3. The third path is connected to the differential pressure transmitter P.

2. The liquid rocket engine propellant tank test buffer system according to claim 1, characterized in that: The six-level adjustment method is as follows: Open the regulating valves G2 and G3 at both ends of buffer container 1 to enter the first-level speed regulation; Close the regulating valves G2 and G3 at both ends of buffer container 1, and open the regulating valves G4 and G5 at both ends of buffer container 2 to enter the secondary speed regulation stage. Close the regulating valves G4 and G5 at both ends of buffer container 2, and open the regulating valves G6 and G7 at both ends of buffer container 3 to enter the third-level speed regulation; Continue to open the regulating valves G2 and G3 at both ends of buffer container 1 to enter the fourth-level speed regulation; Close the regulating valves G2 and G3 at both ends of buffer container 1, and open the regulating valves G4 and G5 at both ends of buffer container 2 to enter the fifth-level speed regulation; Open the regulating valves G2 and G3 at both ends of buffer container 1 to enter the sixth-level speed regulation; The inflation rate is increased by switching between six speed levels in sequence. When the inflation rate is slowed down, the regulating valve is used first to slow down the inflation rate, and then the previous speed level is switched in sequence to slow down the inflation rate.

3. The liquid rocket engine propellant tank test buffer system according to claim 2, characterized in that: It also includes solenoid valves B1 to B2, wherein solenoid valve B1 is installed between shut-off valve K1 and shut-off valve K2; solenoid valve B2 is installed between solenoid valve B1 and the air source; and shut-off valve K9 is also connected in parallel with solenoid valve B2.

4. The liquid rocket engine propellant tank test buffer system according to claim 1, characterized in that: The capacities of buffer container 1, buffer container 2, and buffer container 3 increase sequentially.

5. A test buffer system for a liquid rocket engine propellant tank according to claim 3, characterized in that: It also includes a safety valve A1, which is installed on the gas source interface pipeline. Buffer container 2 is connected in parallel to the side of buffer container 3 away from the gas source, and buffer container 1 is connected in parallel to the side of buffer container 2 away from the gas source.

6. A test buffer system for a liquid rocket engine propellant tank according to claim 5, characterized in that: A shut-off valve K3 and a regulating valve G3 are installed on the side of the buffer container 1 away from the gas source, and a shut-off valve K2 and a regulating valve G2 are installed on the other side; a shut-off valve K5 and a regulating valve G5 are installed on the side of the buffer container 2 away from the gas source, and a shut-off valve K4 and a regulating valve G4 are installed on the other side; a shut-off valve K7 and a regulating valve G7 are installed on the side of the buffer container 3 away from the gas source, and a shut-off valve K6 and a regulating valve G6 are installed on the other side.

7. A test buffer system for a liquid rocket engine propellant tank according to claim 6, characterized in that: It also includes pressure transmitters P1 to P7. The differential pressure transmitter P and pressure transmitters P1 to P7 are connected to the pressure control and display system S1 for displaying the pressure of each channel and controlling the differential pressure value. Pressure transmitter P1 is located between solenoid valve B2 and buffer container 3. Pressure transmitters P2 to P4 are located on the side of buffer containers 1 to 3 near the air source. Pressure transmitter P5 is located between shut-off valve K1 and filter F2. Pressure transmitter P7 is located between shut-off valve K8 and filter F1.

8. A test buffer system for a liquid rocket engine propellant tank according to claim 7, characterized in that: The buffer container 1 is divided into two paths on the side away from the gas source where the shut-off valve K3 and regulating valve G3 are installed. The first path passes through the pressure transmitter P6, filter F3 and pipeline outlet g4 and is connected to the inlet B; the second path is connected to the differential pressure transmitter P.

9. A method for buffering a liquid rocket engine propellant tank during testing, applied to the liquid rocket engine propellant tank testing buffering system described in claim 8, characterized in that: The tank inflation method includes an automatic control method, the specific method of which is as follows: Open manual shut-off valves K1 and K8, and set the target pressure value of the buffer container, the inflation rate of the buffer container, the target pressure value of the storage tank, the inflation rate of the storage tank, and the differential pressure setting value of the storage tank in the pressure control display system S1. The pressure control and display system S1 automatically opens the solenoid valve B2, monitors the pressure values ​​of pressure transmitters P2, P3, and P4, and calculates and automatically controls the opening of regulating valves G2, G4, and G6. Based on the target pressure values ​​of buffer containers 1-3, the pressure values ​​of buffer containers 1-3 are controlled in a closed loop. The pressure control and display system S1 automatically closes the regulating valves G2, G4, G6 and the solenoid valve B2, and the inflation is completed. The pressure control and display system S1 opens the solenoid valve B1, automatically calls the target pressure value of the storage tank, the storage tank inflation rate, and the storage tank differential pressure set value, and monitors the pressure values ​​of pressure transmitters P5, P6, and P7. Based on the rate requirements, a six-level adjustment method for the tank inflation rate is adopted to control the tank inflation rate. When the value of the differential pressure transmitter P is greater than the tank differential pressure value, the opening of regulating valves G2, G4, and G6 is reduced; when the value of the differential pressure transmitter P is less than the tank differential pressure value, the opening of regulating valves G3, G5, and G7 is reduced. The dynamic adjustment control stabilizes the value of the differential pressure transmitter P at the tank differential pressure setpoint.

10. A method for buffering a liquid rocket engine propellant tank during testing, applied to the liquid rocket engine propellant tank testing buffering system described in claim 8, characterized in that: The tank inflation method includes a manual control method, the specific method of which is as follows: Open shut-off valves K9, K2, K4, and K6, and close shut-off valves K1, K3, K5, and K7. Connect the air source to the outlet g1 port of the pipeline and pressurize buffer containers 1, 2, and 3 until the pressure transmitters P2, P3, and P4 reach the required pressure values, and then close shut-off valves K2, K4, K6, and K9. Open shut-off valves K1, K4, K5, and K8. Slowly increase the pressure on both sides of the gas-liquid diaphragm simultaneously. Observe the pressure control display system S1 to ensure that the pressure difference is within the control range. When the pressure in the first chamber connected to inlet A and inlet C exceeds the target pressure value of the storage tank, adjust the opening of the shut-off valve K1 to keep the pressure difference within the control range; when the pressure in the second chamber connected to inlet B exceeds the target pressure value of the storage tank, adjust the opening of the shut-off valve K5 to keep the pressure difference within the control range. When the inflation rate is greater than the target inflation rate, close the shut-off valves K4 and K5 and open the shut-off valves K2 and K3 to use the buffer container 1 for inflation. When the inflation rate is less than the target inflation rate, close the shut-off valves K4 and K5 and open the shut-off valves K6 and K7 to use the buffer container 3 for inflation, or open the corresponding shut-off valves to combine the buffer containers 1 and 3 into the inflation.

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