Hermetic test structure and method for metalized diaphragm tank propulsion systems

Abstract

The application provides a kind of airtight test structure and method of metal diaphragm containing film box propelling system, the method is: to the high pressure area gas cylinder and pressure reducing valve before propelling system inflation, gas enters downstream low pressure area through system pressure reducing valve, by the second tool, the pressure reducing valve, pressure reducing outlet gas is isolated with downstream storage tank, and then the gas of pressure reducing valve is separately introduced into test bench;Gas enters engine before, storage tank gas cavity and storage tank liquid cavity simultaneously from test bench.Inflation to P2 pressure remains unchanged, and low pressure area airtight inspection is carried out;Continue to inflate, P2 pressure remains unchanged under the locking action of system pressure reducing valve, continue to inflate to P1 pressure reaches gas cylinder working pressure, and high pressure area airtight inspection is carried out, and finally system airtight test is completed.The application can simultaneously introduce gas into engine before, storage tank gas cavity and storage tank liquid cavity, avoid the risk of diaphragm displacement caused by poor air intake rate control due to different air intake.

Description

Technical Field

[0001] This invention relates to, specifically, to an airtightness testing structure and method for a propulsion system containing a metal diaphragm tank, and more particularly, to an airtightness testing structure and method for a single-component constant-pressure extrusion propulsion system containing a metal diaphragm tank. Background Technology

[0002] Metal diaphragm propellant tanks possess advantages such as good propellant compatibility, pre-packaged long-term storage, and orderly discharge during operation, and are widely used in various propulsion systems. Among these, monocomponent constant-pressure extrusion propulsion systems containing metal diaphragm propellant tanks are widely used in the propulsion systems of launch vehicles, satellites, spacecraft, probes, and missile weapons. Such propulsion systems generally consist of a gas supply system (including gas cylinders, filling valves, electro-explosive valves, pressure reducing valves, and safety valves), a propellant storage system (metal diaphragm propellant tank + filling valve + ruptured diaphragm), a thrust output system (thrust generator), and a signal acquisition and transmission system (cables, pressure sensors).

[0003] Propulsion systems are essentially gas-liquid transport systems, and leakage is a common failure mode. Therefore, leak testing is crucial, especially for systems requiring long-term on-orbit operation and pre-packaged storage. Ground testing of propulsion systems should cover the system's operating pressure as much as possible to detect and eliminate leaks early. The following two methods are commonly used for leak testing of single-component constant-pressure extrusion propulsion systems with metal diaphragm tanks:

[0004] 1) Method 1

[0005] The system cylinder and pressure reducing valve are filled with gas. After passing through the pressure reducing valve, the gas enters the reservoir chamber. Simultaneously, gas is introduced into the airtightness test port from the reservoir chamber, and then splits into two streams, simultaneously entering the reservoir liquid chamber and the engine front. After filling to the point where the pressure reducing valve is locked (record the locking pressure value), a low-pressure zone airtightness check is performed. Filling continues, with the low-pressure zone pressure remaining constant under the locking action of the pressure reducing valve. After filling to the cylinder's working pressure, a high-pressure zone airtightness check is performed.

[0006] This method can complete the airtightness check of both the low-pressure and high-pressure zones of the system in a single inflation cycle. It utilizes the system's pressure-reducing valve to inflate the low-pressure zone to the valve's locking pressure, covering the actual operating conditions of the system. However, in this method, the gas exiting the system's pressure-reducing valve first enters the reservoir's air chamber, then flows through the airtight platform into the reservoir's liquid chamber and before the engine, failing to guarantee simultaneous air intake into the reservoir's air and liquid chambers. There is a risk that poor intake rate control could lead to pressure imbalances upstream and downstream of the reservoir's metal diaphragm, causing diaphragm displacement. In previous tests, this method has repeatedly resulted in pressure differences in the diaphragm's gas-liquid path, leading to abnormal diaphragm displacement, affecting the normal operation of the reservoir, and necessitating reservoir replacement.

[0007] 2) Method 2

[0008] To address the issue that solution 1 could not guarantee simultaneous air intake into the gas and liquid chambers of the storage tank, resulting in repeated instances of abnormal diaphragm displacement, method 2 employed a step-by-step airtightness approach.

[0009] a) Procedure: Disconnect the outlet pipe of the propulsion system pressure reducing valve from the gas chamber of the storage tank. Connect the outlet pipe of the propulsion system pressure reducing valve to the low-pressure area of ​​the airtight platform. Inflate the system cylinder and the front of the pressure reducing valve with gas. The gas enters the low-pressure area of ​​the airtight platform after passing through the pressure reducing valve. After inflating to the point where the pressure reducing valve is locked (record the locking pressure value), perform an airtightness check on the outlet pipe of the pressure reducing valve. Continue inflating, maintaining a constant pressure in the low-pressure area under the locking action of the pressure reducing valve. After inflating to the working pressure of the gas cylinder, perform an airtightness check on the high-pressure area. During this process, because the outlet pipe is disconnected from the gas chamber of the storage tank, the storage tank and its downstream section have not yet been tested for airtightness.

[0010] b) Procedure: Perform an airtightness test on the tank and its rear section.

[0011] Connect the outlet pipe of the pressure reducing valve of the propulsion system to the gas chamber of the storage tank normally. At the same time, pressurize the gas chamber, the liquid chamber of the storage tank, and the engine with air until the pressure reducing valve lock-up pressure recorded in step a) is reached. Then, perform an airtightness check on the low-pressure area of ​​the propulsion system.

[0012] This method performs airtightness tests on the high-pressure and low-pressure zones separately. When the low-pressure zone is airtight, air is simultaneously introduced into the gas and liquid chambers of the storage tank to ensure pressure balance across the diaphragm and prevent diaphragm displacement. However, this method involves two inflation stages. Furthermore, in step b), during the airtightness test of the storage tank and its downstream section, the system's pressure-reducing valve is not used for self-locking to check the airtightness of the low-pressure zone. Instead, the inflation pressure in step b) is determined solely by referring to the recorded value from step a). This process may introduce errors from manual recording or from the inflation pressure in step b).

[0013] If any of the above errors occur, it may cause a deviation between the inflation pressure in step b) and the actual locking pressure of the pressure reducing valve.

[0014] If the airtight pressure in the low-pressure zone does not reach the locking pressure, the test will not be covered; if it exceeds the locking pressure, it can easily cause the pressure reducing valve to overload, requiring high precision in controlling the low-pressure inflation pressure. Therefore, the reliability of Method 2 is not high. Summary of the Invention

[0015] To address the shortcomings of existing technologies, the purpose of this invention is to provide an airtightness testing structure and method for a propulsion system containing a metal diaphragm.

[0016] According to the present invention, an airtightness test structure for a propulsion system containing a metal diaphragm tank is provided.

[0017] The propulsion system containing a metal diaphragm tank is a single-component constant-pressure extrusion propulsion system with a metal diaphragm tank undergoing airtightness testing;

[0018] The airtightness test structure of the propulsion system containing a metal diaphragm includes a first test port, a second test port, a third test port, a fourth test port, a fifth test port, an airtightness test stand, and a propulsion system.

[0019] The airtightness test bench device includes a high-pressure air supply component and a low-pressure airtightness component.

[0020] The first test port is located at the inlet of the inflation valve of the propulsion system;

[0021] The second test port is located between the electric explosion valve and the pressure reducing valve of the propulsion system.

[0022] Both the first test port and the second test port are connected to the high-pressure gas supply assembly;

[0023] The third and fourth test ports are sequentially located between the pressure reducing valve of the propulsion system and the tank containing the metal diaphragm.

[0024] The fifth test port is located between the isolation diaphragm of the propulsion system and the engine.

[0025] The third test port, the fourth test port, the fifth test port, and the filling port of the metal diaphragm tank are all connected to the low-pressure airtight assembly.

[0026] Preferably, the second test port is connected to the propulsion system via the first tooling.

[0027] Preferably, the third test port is connected to the propulsion system via a second tooling.

[0028] Preferably, the fourth test port is connected to the propulsion system via a third tooling.

[0029] Preferably, the fifth test port is connected to the propulsion system via the fourth tooling.

[0030] Preferably, the high-pressure gas supply assembly includes a high-pressure gas source, a first valve, and a first pressure measuring element;

[0031] The high-pressure gas source is connected to the first test port and the second test port respectively through the first valve;

[0032] The first pressure measuring element is used to measure the pressure at the rear end of the first valve.

[0033] Preferably, the low-pressure airtight component includes a low-pressure module of the airtightness test bench, a second valve, and a second pressure measuring element;

[0034] The low-pressure module of the airtightness test bench includes one inlet, three outlets, and one exhaust port;

[0035] The inlet of the low-pressure module of the airtightness test bench is connected to the third test port, and the three outlets are connected to the fourth test port, the filling port, and the fifth test port, respectively. The exhaust port is connected to the outside through the second valve.

[0036] The second pressure measuring element is used to measure the gas pressure at the exhaust port.

[0037] Preferably, the first tooling is a three-way valve, the second tooling is a three-way valve, the third tooling is a three-way valve, and the fourth tooling is a three-way valve.

[0038] According to the airtightness test structure of a propulsion system with a metal diaphragm tank provided by the present invention, the airtightness test structure of the propulsion system with a metal diaphragm tank further includes the following steps:

[0039] Step S1: Connect the first test port and the second test port to the outlet of the high-pressure gas supply component of the airtightness test bench through pipes;

[0040] Step S2: Connect the third test port to the low-pressure module of the airtightness test bench, and then connect the low-pressure module of the airtightness test bench to the fourth test port, the filling port, and the fifth test port respectively.

[0041] Step S3: Open the first valve, and the gas enters the gas cylinder and pressure reducing valve of the propulsion system. After passing through the pressure reducing valve, it enters the low-pressure module of the dense test bench through the third test port. From the low-pressure module of the dense test bench, it simultaneously enters the engine front, the gas chamber of the storage tank, and the liquid chamber of the storage tank of the propulsion system.

[0042] Step S4: During inflation, the pressure of the first and second pressure measuring devices rises slowly until the pressure of the second pressure measuring device remains constant; then the first valve is closed to perform an airtightness check on the low-pressure area of ​​the propulsion system; the low-pressure area of ​​the propulsion system is the part after the pressure reducing valve in the propulsion system.

[0043] Step S5: Open the first valve to continue inflation. During the process, the pressure of the first pressure measuring element continues to rise, while the pressure of the second pressure measuring element remains unchanged under the locking action of the system pressure reducing valve.

[0044] Step 6: After inflating the gas until the pressure of the first pressure measuring element reaches the working pressure of the gas cylinder, close the first valve and perform an airtightness check on the high-pressure zone of the propulsion system; the high-pressure zone of the propulsion system is the part before the pressure reducing valve in the propulsion system.

[0045] Step 7: After the airtightness check is completed, slowly open the second valve to release the air.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. This invention utilizes the low-pressure module of the airtightness test bench to simultaneously introduce gas into the engine front, the gas chamber of the reservoir, and the liquid chamber of the reservoir. This avoids the risk of diaphragm displacement caused by poor control of the intake rate due to non-simultaneous gas introduction, resulting in pressure imbalance between the upstream and downstream of the reservoir metal diaphragm.

[0048] 2. This invention utilizes the self-locking of the pressure reducing valve to achieve airtightness inspection in the low-pressure area. The entire airtightness inspection process does not require reference to recorded values, avoiding the phenomenon in step b) of the background technology where the airtightness pressure in the low-pressure area may not reach or exceed the locking pressure due to the need to refer to recorded values, thus improving the reliability of airtightness inspection. Attached Figure Description

[0049] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0050] Figure 1 This is a schematic diagram of a single-component constant-pressure extrusion propulsion system containing a metal diaphragm tank; it shows the first test port, the second test port, the third test port, the fourth test port, and the fifth test port.

[0051] Figure 2 This is a schematic diagram illustrating the principle of the present invention;

[0052] The diagram shows:

[0053] Detailed Implementation

[0054] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0055] This invention provides an airtightness test structure for a propulsion system containing a metal diaphragm tank, such as... Figure 1-2 As shown, the propulsion system containing a metal diaphragm tank is a single-component constant-pressure extrusion propulsion system containing a metal diaphragm tank, and its airtightness is tested.

[0056] The airtightness test structure of the propulsion system with metal diaphragm tank includes a first test port 3, a second test port 4, a third test port 5, a fourth test port 6, a fifth test port 7, an airtightness test stand, and a propulsion system 200; in a preferred embodiment, the airtightness test stand is the KDD03-16 airtightness test stand developed by the Shanghai Space Propulsion Institute.

[0057] The airtightness test bench includes a high-pressure air supply component 1 and a low-pressure airtightness component 2; the first test port 3 is located at the inlet of the inflation valve 101 of the propulsion system 200; the inflation valve 101 is installed on the branch between the gas cylinder 100 and the electric explosion valve 102 of the propulsion system 200.

[0058] The second test port 4 is located between the electric explosion valve 102 and the pressure reducing valve 103 in the propulsion system 200; both the first test port 3 and the second test port 4 are connected to the high-pressure gas supply assembly 1.

[0059] The third test port 5 and the fourth test port 6 are sequentially arranged between the pressure reducing valve 103 of the propulsion system 200 and the storage tank 107 containing the metal diaphragm; the fifth test port 7 is arranged between the isolation diaphragm 104 of the propulsion system 200 and the engine 105; the third test port 5, the fourth test port 6, the fifth test port 7 and the filling port 106 of the metal diaphragm storage tank are all connected to the low-pressure airtight assembly 2.

[0060] The second test port 4 is connected to the propulsion system via the first fixture; the third test port 5 is connected to the propulsion system via the second fixture; the fourth test port 6 is connected to the propulsion system via the third fixture; and the fifth test port 7 is connected to the propulsion system via the fourth fixture. In a preferred embodiment, the first fixture is a three-way valve, the second fixture is a three-way valve, the third fixture is a three-way valve, and the fourth fixture is a three-way valve.

[0061] The high-pressure gas supply assembly 1 includes a high-pressure gas source 11, a first valve 12, and a first pressure measuring element 13;

[0062] The high-pressure gas source 11 is connected to the first test port 3 and the second test port 4 respectively through the first valve 12; the first pressure measuring element 13 is used to measure the pressure at the rear end of the first valve 12. In a preferred embodiment, the first pressure measuring element 13 is a pressure gauge P1.

[0063] The low-pressure airtightness component 2 includes an airtightness test bench low-pressure module 21, a second valve 23, and a second pressure measuring element 22. The airtightness test bench low-pressure module 21 includes one inlet, three outlets, and one exhaust port. In a preferred embodiment, the airtightness test bench low-pressure module 21 is a five-way pipe fitting. The inlet of the airtightness test bench low-pressure module 21 is connected to the third test port 5, and the three outlets are respectively connected to the fourth test port 6, the filling port 106, and the fifth test port 7. The exhaust port is connected to the outside through the second valve 23. The second pressure measuring element 22 is used to measure the gas pressure at the exhaust port. In a preferred embodiment, the first pressure measuring element 13 is a pressure gauge P2.

[0064] The present invention also provides an airtightness test structure for a propulsion system with a metal diaphragm tank. The airtightness test structure for the propulsion system with a metal diaphragm tank further includes the following steps:

[0065] Step S1: Connect the first test port 3 and the second test port 4 to the outlet of the high-pressure gas supply component 1 of the airtightness test bench through pipelines; control the high-pressure gas through the first valve 12 and the first pressure measuring element 13;

[0066] Step S2: Connect the third test port 5 to the low-pressure module 21 of the airtightness test bench, and then connect the low-pressure module 21 of the airtightness test bench to the fourth test port 6, the filling port 106, and the fifth test port 7 respectively. Specifically, a test fixture (such as a three-way valve) is set at the third test port 5 after the pressure reducing valve of the system under test. The fixture is connected to the low-pressure module 21 of the airtightness test bench through a pipeline. The low-pressure module 21 of the airtightness test bench is connected to the fourth test port 6, the filling port 106, and the fifth test port 7 respectively.

[0067] Step S3: Slowly open the first valve 12, and the gas enters the gas cylinder 100 and pressure reducing valve 103 of the propulsion system 200. After passing through the pressure reducing valve, it enters the low-pressure module 21 of the dense test bench through the third test port 5. From the low-pressure module 21 of the dense test bench, it simultaneously enters the engine front, the gas chamber of the storage tank and the liquid chamber of the storage tank of the propulsion system 200.

[0068] In step S4, during inflation, the pressure of the first pressure measuring element 13 and the pressure of the second pressure measuring element 22 slowly increase until the pressure of the second pressure measuring element 22 remains constant (at this point, the pressure of the second pressure measuring element 22 can be recorded, which is the closing pressure of the pressure reducing valve). Then, the first valve 12 is closed, and an airtightness check is performed on the low-pressure area of ​​the propulsion system 200. Preferably, a single-point helium mass spectrometry leak detection method can be used to perform the airtightness check on the low-pressure area of ​​the propulsion system 200. The low-pressure area of ​​the propulsion system 200 is the part after the pressure reducing valve of the propulsion system.

[0069] Step S5: Open the first valve 12 to continue inflation. During the process, the pressure of the first pressure measuring element 13 continues to rise, while the pressure of the second pressure measuring element 22 remains unchanged under the locking action of the system pressure reducing valve 103.

[0070] Step 6: After the pressure of the first pressure measuring element 13 reaches the working pressure of the gas cylinder 100, close the first valve 12 and perform an airtightness check on the high-pressure area of ​​the propulsion system 200. Preferably, the airtightness check on the high-pressure area of ​​the propulsion system 200 can be performed using a single-point helium mass spectrometry leak detection method. The high-pressure area of ​​the propulsion system 200 is the part before the pressure reducing valve in the propulsion system 200.

[0071] Step 7: After the airtightness check is completed, slowly open the second valve 23 to release the air.

[0072] In summary, the working principle of this invention is as follows: Gas is charged into the high-pressure zone cylinder and pressure reducing valve of the propulsion system 200. The gas enters the downstream low-pressure zone through the system pressure reducing valve. A test fixture (such as a three-way valve) is set at the third test port 5 after the pressure reducing valve of the system under test to isolate the gas at the pressure reducing valve 103 outlet from the downstream storage tank. The gas from the pressure reducing valve 103 is introduced separately into the test bench. The gas simultaneously enters the engine front, the storage tank gas chamber, and the storage tank liquid chamber from the test bench. After charging until the P2 pressure remains constant (the pressure reducing valve is locked, and the downstream pressure remains constant) (at this time, the P2 pressure can be recorded), a low-pressure zone airtightness check is performed. Charging continues, and during this process, the P2 pressure remains constant under the locking action of the system pressure reducing valve. Charging continues until the P1 pressure reaches the working pressure of the cylinder, after which a high-pressure zone airtightness check is performed, finally completing the system airtightness test.

[0073] This invention sets up a special test fixture (such as a three-way valve) at the upstream test port of the gas chamber of the metal diaphragm reservoir of the propulsion system under test; gas is filled into the gas cylinder 100 and the second test port 4 before the pressure reducing valve; the gas is isolated from the reservoir through the test fixture such as the three-way valve and introduced into the low-pressure module 21 of the airtightness test bench; the gas is divided into three paths by the low-pressure module 21 of the airtightness test bench and simultaneously introduced into the gas chamber of the reservoir, the liquid chamber of the reservoir, and the front of the engine; after filling to the locking pressure of the pressure reducing valve 103 (at this time, the pressure recorded by the second pressure measuring element 22 can be compared with the designed locking pressure of the pressure reducing valve to test).

[0074] (To verify the accuracy of the actual locking pressure of the pressure reducing valve, perform an airtightness check on the low-pressure zone after pressure reducing valve 103; continue filling with gas (the low-pressure zone pressure remains unchanged after the pressure reducing valve is locked) until the working pressure of the gas cylinder 100, then perform an airtightness check on the high-pressure zone before the pressure reducing valve. The test is completed through steps 1 to 7. By testing the pressure reducing valve locking pressure during filling, checking the system's low-pressure airtightness, and checking the system's high-pressure airtightness, the system airtightness test is finally completed.

[0075] This invention enables airtightness checks of the high-pressure and low-pressure zones of a single-component constant-pressure extrusion propulsion system containing a metal diaphragm tank through a single inflation process. While covering the pressure-reducing valve's locking pressure, it ensures simultaneous air intake before and after the metal diaphragm, preventing displacement of the diaphragm during the airtightness process. This achieves beneficial effects such as improved testing efficiency, controlled testing risks, and guaranteed testing coverage, ensuring the reliability of the propulsion system for long-term on-orbit operation and long-term pre-packaged storage.

[0076] This invention ensures that the system's airtightness meets the requirements of actual operating conditions without causing testing risks, effectively improving the reliability of the propulsion system during long-term on-orbit operation and long-term pre-packaged storage. This invention effectively solves the airtightness testing problem of monocomponent constant-pressure extrusion propulsion systems with metal diaphragm tanks, effectively improving testing efficiency, controlling testing risks, ensuring test coverage, and guaranteeing the reliability of the propulsion system during long-term on-orbit operation and long-term storage. This invention can be applied to all constant-pressure extrusion propulsion systems (monocomponent, bicomponent, and multicomponent propulsion systems) containing metal diaphragm tanks, as well as other gas-liquid transfer systems with similar structures and operating principles.

[0077] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0078] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A test structure for the airtightness of a propulsion system containing a metal diaphragm tank, characterized in that, The propulsion system containing a metal diaphragm tank is a single-component constant-pressure extrusion propulsion system with a metal diaphragm tank undergoing airtightness testing; The airtightness test structure of the propulsion system containing a metal diaphragm includes a first test port (3), a second test port (4), a third test port (5), a fourth test port (6), a fifth test port (7), an airtightness test stand, and a propulsion system (200). The airtightness test bench includes a high-pressure air supply component (1) and a low-pressure airtightness component (2). The first test port (3) is located at the inlet of the inflation valve (101) of the propulsion system (200); The second test port (4) is located between the electric explosion valve (102) and the pressure reducing valve (103) of the propulsion system (200); Both the first test port (3) and the second test port (4) are connected to the high-pressure gas supply assembly (1); The third test port (5) and the fourth test port (6) are sequentially arranged between the pressure reducing valve (103) of the propulsion system (200) and the storage tank (107) containing the metal diaphragm. The fifth test port (7) is located between the isolation diaphragm (104) of the propulsion system (200) and the engine (105); The third test port (5), the fourth test port (6), the fifth test port (7) and the filling port (106) of the metal diaphragm tank are all connected to the low-pressure airtight assembly (2); The high-pressure gas supply assembly (1) includes a high-pressure gas source (11), a first valve (12), and a first pressure measuring element (13). The high-pressure gas source (11) is connected to the first test port (3) and the second test port (4) respectively through the first valve (12); The first pressure measuring element (13) is used to measure the pressure at the rear end of the first valve (12); The low-pressure airtight component (2) includes a low-pressure module (21) of an airtight test bench, a second valve (23) and a second pressure measuring element (22); The low-pressure module (21) of the airtightness test bench includes one inlet, three outlets, and one exhaust port; The inlet of the low-pressure module (21) of the airtight test bench is connected to the third test port (5), and the three outlets are connected to the fourth test port (6), the filling port (106), and the fifth test port (7) respectively. The exhaust port is connected to the outside through the second valve (23). The second pressure measuring element (22) is used to measure the gas pressure at the exhaust port.

2. The airtightness test structure for the propulsion system containing a metal diaphragm tank according to claim 1, characterized in that, The second test port (4) is connected to the propulsion system through the first tooling.

3. The airtightness test structure for a propulsion system containing a metal diaphragm as described in claim 1, characterized in that, The third test port (5) is connected to the propulsion system via the second tooling.

4. The airtightness test structure for a propulsion system containing a metal diaphragm as described in claim 1, characterized in that, The fourth test port (6) is connected to the propulsion system via the third tooling.

5. The airtightness test structure for a propulsion system containing a metal diaphragm tank according to claim 1, characterized in that, The fifth test port (7) is connected to the propulsion system via the fourth tooling.

6. The airtightness test structure for a propulsion system containing a metal diaphragm tank according to claim 1, characterized in that, The first tooling is a three-way valve, the second tooling is a three-way valve, the third tooling is a three-way valve, and the fourth tooling is a three-way valve.

7. An airtightness test structure for a propulsion system containing a metal diaphragm tank, characterized in that, The airtightness test structure for the propulsion system with a metal diaphragm as described in any one of claims 1-6 further includes the following steps: Step S1: Connect the first test port (3) and the second test port (4) to the outlet of the high-pressure gas supply component (1) of the airtightness test bench through pipes; Step S2: Connect the third test port (5) to the low-pressure module (21) of the airtightness test bench, and then connect the low-pressure module (21) of the airtightness test bench to the fourth test port (6), the filling port (106), and the fifth test port (7) respectively. Step S3: Open the first valve (12), and the gas enters the gas cylinder (100) and pressure reducing valve (103) of the propulsion system (200). After passing through the pressure reducing valve, the gas enters the low-pressure module (21) of the dense test bench through the third test port (5). From the low-pressure module (21) of the dense test bench, the gas enters the engine front, the gas tank chamber and the liquid tank chamber of the propulsion system (200). In step S4, during the inflation process, the pressure of the first pressure measuring element (13) and the pressure of the second pressure measuring element (22) slowly rise until the pressure of the second pressure measuring element (22) remains constant; then the first valve (12) is closed, and an airtightness check is performed on the low-pressure area of ​​the propulsion system (200); the low-pressure area of ​​the propulsion system (200) is the part after the pressure reducing valve in the propulsion system (200); Step S5: Open the first valve (12) to continue inflation. During the process, the pressure of the first pressure measuring element (13) continues to rise, while the pressure of the second pressure measuring element (22) remains unchanged under the locking action of the system pressure reducing valve (103). Step 6: After the pressure of the first pressure measuring element (13) reaches the working pressure of the gas cylinder (100), close the first valve (12) and perform an airtightness check on the high-pressure zone of the propulsion system (200); the high-pressure zone of the propulsion system (200) is the part before the pressure reducing valve in the propulsion system (200); Step 7: After the airtightness check is completed, slowly open the second valve (23) to release the air.

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