An air tightness detection device

Abstract

This invention relates to the field of testing equipment technology and provides an airtightness testing device, including an airtightness detector, an air intake assembly, and an elastic sealing plug. The air intake assembly includes a hollow air intake pipe and a support base. One end of the air intake pipe is fixedly connected to the support base, and the other end is provided with an external interface for connecting an external airtightness detector. The support base has a through-hole for connecting the air intake pipe and a cavity. The sealing plug includes an arcuate portion adapted to a narrow throat, a first limiting portion, and a second limiting portion. The sealing plug has a through-hole for the air intake pipe to pass through. The through-hole is located on the inner wall of the first limiting portion, which is recessed inward to form an abutment groove for restricting the movement of the support base. In this invention, the airtightness testing device has a simple structure, is quick to install and disassemble, ensures the reliability of liquid-fueled rocket engine quality, effectively improves the efficiency of liquid-fueled rocket assembly and testing, and shortens the preparation time before rocket launch.

Description

Technical Field

[0001] This invention belongs to the field of testing equipment technology, and particularly relates to an airtightness testing device. Background Technology

[0002] Liquid-fueled rocket engines use liquid propellant as the combustion medium, which consists of a fuel and an oxidizer. These components mix and burn within the combustion chamber to produce high-temperature, high-pressure gas, which is then expelled through the nozzle to generate thrust. Therefore, the engine thrust chamber must have excellent sealing properties to prevent the volatile liquid propellant and the high-temperature, high-pressure gas from leaking outside the combustion chamber during engine operation. During rocket engine assembly, testing, and final assembly, the thrust chamber requires multiple airtightness tests to ensure that the engine's quality and performance meet technical requirements.

[0003] Because engine thrust chambers are typically designed with a Laval profile and a unique double-arc throat structure, traditional engine thrust chamber airtightness testing equipment can only perform airtightness testing by installing a sealing device at the thrust chamber outlet. However, using existing airtightness testing methods and equipment requires adding an installation structure to the engine to connect the airtightness testing equipment, increasing the overall weight and size of the engine. If this installation structure is omitted to avoid increasing the overall weight, airtightness testing can only be performed before the engine is assembled. Once the engine is assembled into the system or installed in the rocket section, airtightness testing is impossible, potentially leading to quality issues and affecting the reliability of liquid-fueled rocket engines. Furthermore, existing airtightness testing devices have complex structures and are cumbersome to install and disassemble, making them unsuitable for engine airtightness testing within the extremely limited operating space of a rocket, thus impacting the efficiency of liquid-fueled rocket assembly and testing. Summary of the Invention

[0004] The purpose of this invention is to provide an airtightness testing device, which aims to solve the technical problems of existing airtightness testing equipment requiring the addition of an installation structure on the engine to connect the airtightness testing equipment in order to complete the airtightness testing of the thrust chamber, resulting in an increase in the overall mass of the engine, and the cumbersome installation and disassembly of the airtightness testing equipment, which affects the efficiency of the assembly and testing of liquid launch vehicles.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An airtightness testing device is provided for testing the sealing performance of the thrust chamber of a liquid rocket engine. The thrust chamber includes a cavity and a Laval nozzle fixedly connected to the cavity. The Laval nozzle communicates with the interior and exterior of the cavity and has a narrow throat. The airtightness testing device includes:

[0006] Air tightness detector;

[0007] An air intake assembly includes a hollow air intake pipe and a support base. One end of the air intake pipe is fixedly connected to the support base, and the other end is provided with an external interface for connecting the air tightness detector. The support base is provided with a clearance hole for connecting the air intake pipe and the cavity. The outer diameter of the support base is smaller than the inner diameter of the narrow throat.

[0008] The sealing plug has an elasticity and includes an arcuate portion adapted to the narrow throat, and a first limiting portion and a second limiting portion respectively disposed on opposite sides of the arcuate portion. The sealing plug has a through hole through which the air intake pipe passes. The through hole is located on the inner side wall of the first limiting portion and is recessed inward to form an abutment groove for restricting the movement of the support.

[0009] In one embodiment, the support base includes a support portion and a connecting portion fixedly connected to the end of the air intake pipe. The support portion is frustum-shaped and has a clearance hole through it. The inner and outer diameters of the support portion gradually decrease from the end away from the connecting portion toward the end closer to the connecting portion. The inner diameter of the abutment groove gradually decreases from the side away from the arc portion toward the side closer to the arc portion. The outer surface of the support portion and the inner wall of the abutment groove are fitted together.

[0010] In one embodiment, the end of the air intake pipe is provided with a mounting portion for fixing the support base. The mounting portion is provided with a mounting hole for the connecting portion to be inserted. The inner sidewall of the mounting hole is provided with an internal thread, and the surface of the connecting portion is provided with an external thread that matches the internal thread.

[0011] In one embodiment, the outer surface of the mounting portion is recessed inward to form a sealing groove for mounting a sealing ring.

[0012] In one embodiment, the circumferential sidewall of the first limiting portion is provided with a sealing protrusion that abuts against the inner wall of the cavity.

[0013] In one embodiment, the airtightness detection device further includes a fixing component and an operating handle sleeved on the air inlet pipe, wherein the fixing component is used to fix the operating handle and the sealing plug.

[0014] In one embodiment, the operating handle includes a support rod and an operating part disposed at the end of the support rod. The fixing assembly includes a first fixing ring sleeved on the support rod, a second fixing ring sleeved on the sealing plug, and a plurality of fixing screws for fixing the first fixing ring and the second fixing ring. The surface of the second limiting part is recessed inward to form a fixing groove for installing the second fixing ring.

[0015] In one embodiment, the surface of the operating part is provided with an anti-slip structure.

[0016] In one embodiment, a limiting ring is fitted on the air intake pipe to restrict the movement of the operating handle, and the surface of the air intake pipe is recessed inward to form a first limiting groove into which the limiting ring is inserted.

[0017] In one embodiment, the surface of the air intake pipe is recessed inward to form a second limiting groove for the limiting retaining ring to be inserted. The first limiting groove and the second limiting groove are spaced apart, and the second limiting groove is located on the side of the first limiting groove facing the sealing plug.

[0018] The beneficial effects of the airtightness testing device provided by the present invention are as follows: Compared with the existing airtightness testing devices, the airtightness testing device of the present invention is used to test the sealing performance of the thrust chamber of a liquid rocket engine. Since the thrust chamber is connected to the inside and outside of the cavity through a Laval nozzle, and the Laval nozzle has a narrow throat, the airtightness testing device provides an arc portion adapted to the narrow throat on an elastic sealing plug. A first limiting portion and a second limiting portion are provided on opposite sides of the arc portion. By utilizing the elastic deformation of the sealing plug, the first limiting portion is inserted into the cavity of the thrust chamber, and the surface of the arc portion is tightly fitted to the inner wall of the narrow throat. Then, the support seat fixedly connected to the end of the air inlet pipe is placed into the abutment groove on the sealing plug to support and fix the sealing plug, preventing the sealing plug from slipping off the thrust chamber. During the airtightness test, the air pressure inside the thrust chamber acts on the support base, causing the support base to compress the sealing plug, resulting in elastic deformation of the sealing plug. The first limiting part tightly fits against the inner wall of the thrust chamber, thus sealing the test gas. Simultaneously, during the test, the sealing plug is positioned at the narrow throat of the thrust chamber, where its cross-sectional area is minimized. Under the same test pressure, the axial force on the thrust chamber is minimized, preventing damage to the inner wall of the thrust chamber during the test. The airtightness testing device of this invention has a simple structure and is quick to install and disassemble. It can perform airtightness testing on the thrust chamber not yet assembled with the engine, and is also suitable for airtightness testing of the engine thrust chamber during final assembly in extremely limited operating space. This ensures the reliability of the liquid-fueled rocket engine, effectively improves the efficiency of liquid-fueled rocket assembly and testing, and shortens the preparation time before rocket launch. Attached Figure Description

[0019] Figure 1 This is a schematic cross-sectional view of an airtightness detection device provided in one embodiment of the present invention. Figure 1 ;

[0020] Figure 2 This is a schematic cross-sectional view of an airtightness detection device provided in one embodiment of the present invention. Figure 2 ;

[0021] Figure 3 This is a schematic cross-sectional view of an airtightness detection device provided in one embodiment of the present invention. Figure 3 ;

[0022] Figure 4 This is a cross-sectional view of the sealing plug of an airtightness detection device provided in one embodiment of the present invention;

[0023] Figure 5 This is a cross-sectional view of the air inlet pipe of an airtightness detection device provided in an embodiment of the present invention;

[0024] Figure 6 This is a cross-sectional view of the support base of an airtightness testing device provided in one embodiment of the present invention;

[0025] Figure 7 This is a cross-sectional view of the operating handle of an airtightness detection device provided in an embodiment of the present invention.

[0026] The following are the labeling elements in the figure:

[0027] 1. Thrust chamber; 11. Laval nozzle; 111. Narrow throat; 2. Sealing ring; 3. Limiting ring; 4. Sealing plug; 41. First limiting part; 411. Sealing protrusion; 42. Arc part; 43. Second limiting part; 431. Fixing groove; 44. Penetrating hole; 45. Abutment groove; 5. Intake assembly; 51. Intake pipe; 511. External interface; 512. Mounting part; 5121. Mounting hole; 5122. Sealing groove; 513. First limiting groove; 514. Second limiting groove; 52. Support base; 521. Clearance hole; 522. Support part; 523. Connecting part; 6. Operating handle; 61. Support rod; 62. Operating part; 621. Anti-slip structure; 7. Fixing assembly; 71. First fixing ring; 72. Second fixing ring; 73. Fixing screw. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] The airtightness detection device of the present invention has an arcuate portion 42 adapted to the narrow throat 111 on an elastic sealing plug 4. A first limiting portion 41 and a second limiting portion 43 are provided on opposite sides of the arcuate portion 42. The sealing plug 4 can generate elastic deformation, so that the first limiting portion 41 is inserted into the cavity of the thrust chamber 1 and the surface of the arcuate portion 42 is tightly fitted with the inner wall of the narrow throat 111. Then, the support seat 52 fixedly connected to the end of the air intake pipe 51 is placed into the abutment groove 45 on the sealing plug 4 to support and fix the sealing plug 4 and prevent the sealing plug 4 from slipping off the thrust chamber 1. During the airtightness test, the air pressure inside the thrust chamber 1 acts on the support base 52, causing the support base 52 to compress the sealing plug 4, resulting in elastic deformation of the sealing plug 4. The first limiting part 41 fits tightly against the inner wall of the thrust chamber 1, thereby sealing the test gas. Simultaneously, during the test, the sealing plug 4 is positioned at the narrow throat 111 of the thrust chamber 1, where its cross-sectional area is minimized. Under the same test pressure, the axial force on the thrust chamber 1 is minimized, thus preventing damage to the inner wall of the thrust chamber 1 during the test. The airtightness testing device of this invention has a simple structure and is quick to install and disassemble. It can perform airtightness testing on the thrust chamber 1 not only when the engine is not assembled, but also is suitable for performing airtightness testing on the engine thrust chamber 1 during the final assembly process where operating space is extremely limited. This ensures the reliability of the liquid launch vehicle engine's quality, effectively improves the operational efficiency of liquid launch vehicle final assembly and testing, and shortens the preparation time before rocket launch.

[0030] Example 1

[0031] Please refer to the following: Figures 1 to 3 In this embodiment, the present invention provides an airtightness testing device for detecting the sealing performance of the thrust chamber 1 of a liquid rocket engine. The thrust chamber 1 includes a cavity and a Laval nozzle 11 fixedly connected to the cavity. The Laval nozzle 11 communicates the interior and exterior of the cavity and has a narrow throat 111. The airtightness testing device includes:

[0032] Air tightness detector;

[0033] The air intake assembly 5 includes a hollow air intake pipe 51 and a support base 52. One end of the air intake pipe 51 is fixedly connected to the support base 52, and the other end is provided with an external interface 511 for connecting an external airtightness detector. The support base 52 is provided with a clearance hole 521 for connecting the air intake pipe 51 and the cavity. The outer diameter of the support base 52 is smaller than the inner diameter of the narrow throat 111.

[0034] The sealing plug 4 is elastic and includes an arcuate portion 42 adapted to the narrow throat 111, and a first limiting portion 41 and a second limiting portion 43 respectively disposed on opposite sides of the arcuate portion 42. The sealing plug 4 is provided with a through hole 44 for the air intake pipe 51 to pass through. The through hole 44 is located on the inner side wall of the first limiting portion 41 and is recessed inward to form an abutment groove 45 for restricting the movement of the support seat 52.

[0035] When an airtightness test is required on the thrust chamber 1 of the engine, the support seat 52 of the intake assembly 5 is pushed away from the abutment groove 45 of the sealing plug 4. Since the outer diameter of the support seat 52 is smaller than the inner diameter of the narrow throat 111, the support seat 52 is inserted into the cavity of the thrust chamber 1 through the narrow throat 111. The sealing plug 4 can generate elastic deformation, and the first limiting part 41 loses the support of the support seat 52. The first limiting part 41 is squeezed by external force to pass through the narrow throat 111 and extend into the cavity of the thrust chamber 1, so that the surface of the arc part 42 of the sealing plug 4 is tightly fitted with the inner wall of the narrow throat 111. At this time, by pulling the intake pipe 51, the support seat 52 fixedly connected to the end of the intake pipe 51 is inserted into the abutment groove 45 on the sealing plug 4, which provides support and fixation for the sealing plug 4 and prevents the sealing plug 4 from slipping off the thrust chamber 1. The airtightness detector is connected through the external interface 511 of the air inlet pipe 51. The detected gas flows through the hollow air inlet pipe 51 and the clearance hole 521 of the support seat 52 and enters the cavity of the thrust chamber 1, pressurizing the inside of the cavity. Under the action of the gas pressure, the gas pressure in the thrust chamber 1 acts on the support seat 52, and the support seat 52 is forced to squeeze the sealing plug 4, causing the sealing plug 4 to undergo elastic deformation. The first limiting part 41 is tightly attached to the inner wall of the thrust chamber 1, thereby playing the role of sealing the detected gas.

[0036] When the air tightness test is completed, push the support seat 52 away from the abutment groove 45 of the sealing plug 4, so that the sealing plug 4 loses the support and fixing effect of the support seat 52. Then, pull the sealing plug 4 out of the thrust chamber 1 by external force to complete the removal of the air tightness test device from the engine.

[0037] During the testing process, the sealing plug 4 is positioned at the narrow throat 111 of the thrust chamber 1, where its cross-sectional area is minimized. Under the same testing pressure, the axial force on the thrust chamber 1 is minimized, thus preventing damage to the inner wall of the thrust chamber 1 during the testing process. Simultaneously, the airtightness testing device has a simple structure and is quick to install and disassemble. It can perform airtightness testing on the thrust chamber 1 not only before the engine is assembled, but also is suitable for airtightness testing of the engine thrust chamber 1 during the final assembly process where operating space is extremely limited. This ensures the reliability of the liquid-fueled rocket engine's quality, effectively improves the operational efficiency of liquid-fueled rocket assembly and testing, and shortens the preparation time before rocket launch.

[0038] Optionally, the sealing plug 4 is made of rubber and is manufactured using a molding process.

[0039] Example 2

[0040] Please refer to the following: Figure 4 and Figure 6 In this embodiment, the support base 52 of the air intake assembly 5 includes a support portion 522 and a connecting portion 523 fixedly connected to the end of the air intake pipe 51. The support portion 522 is frustum-shaped and has a clearance hole 521 through it. The inner diameter and outer diameter of the support portion 522 gradually decrease from the end away from the connecting portion 523 toward the end closer to the connecting portion 523. The inner diameter of the abutment groove 45 gradually decreases from the side away from the arc portion 42 toward the side closer to the arc portion 42. The outer surface of the support portion 522 and the inner wall of the abutment groove 45 are fitted together. By setting the inner surface of the support 522 into a conical shape, the force-bearing area of ​​the gas pressure in the thrust chamber 1 acting on the inner surface of the support 522 can be increased. This allows the force to be applied more evenly to the first limiting part 41, making the outer surface of the support 522 and the inner wall of the abutment groove 45 fit more closely. At the same time, the first limiting part 41 of the sealing plug 4 is squeezed and undergoes elastic deformation, making the first limiting part 41 fit more tightly against the inner wall of the thrust chamber 1. This helps to improve the sealing effect and prevent gas leakage.

[0041] Optionally, the inclination angle of the inner wall of the abutment groove 45 is the same as the inclination angle of the outer wall of the support portion 522.

[0042] Optionally, the inclination angle of the inner sidewall of the abutment groove 45 is 45° to 60°, and the inclination angle of the outer sidewall of the support portion 522 is 45° to 60°.

[0043] Example 3

[0044] Please refer to further information. Figure 4 In this embodiment, the circumferential sidewall of the first limiting part 41 of the sealing plug 4 is provided with a sealing protrusion 411 that abuts against the inner wall of the cavity. The sealing protrusion 411 is interference-fitted with the narrow throat 111 of the thrust chamber 1, so that the first limiting part 41 fits more tightly against the inner wall of the thrust chamber 1, which is beneficial to improving the sealing effect and preventing gas leakage.

[0045] Example 4

[0046] Please refer to the following: Figure 5 and Figure 6In this embodiment, the end of the intake pipe 51 is provided with a mounting part 512 for fixing and connecting the support base 52. The mounting part 512 is provided with a mounting hole 5121 for the connecting part 523 to be inserted. The inner sidewall of the mounting hole 5121 is provided with an internal thread, and the surface of the connecting part 523 is provided with an external thread that matches the internal thread. By inserting the connecting part 523 of the support base 52 into the mounting hole 5121 on the mounting part 512, and by threaded connection, the support base 52 is securely connected to the end of the intake pipe 51. The structure is simple and easy to assemble and disassemble.

[0047] Example 5

[0048] Please refer to the following: Figure 3 and Figure 5 In this embodiment, the outer surface of the mounting portion 512 of the air intake pipe 51 is recessed inward to form a sealing groove 5122 for mounting the sealing ring 2. The sealing ring 2 is fitted into the sealing groove 5122 of the mounting portion 512 to seal the gap between the sealing plug 4 and the air intake pipe 51, prevent gas leakage, and improve the sealing effect.

[0049] Example 6

[0050] Please refer to the following: Figure 1 , Figure 2 , Figure 3 and Figure 7 In this embodiment, the airtightness testing device also includes a fixing component 7 and an operating handle 6 sleeved on the air inlet pipe 51. The fixing component 7 is used to fix the operating handle 6 and the sealing plug 4. By fixing the operating handle 6 and the sealing plug 4 through the fixing component 7, when the operator performs airtightness testing on the thrust chamber 1 of the engine, if the sealing plug 4 loses the support of the support seat 52, the operator can apply external force to the sealing plug 4 through the operating handle 6, thereby squeezing the sealing plug 4, so that the first limiting part 41 passes through the narrow throat 111 and extends into the cavity of the thrust chamber 1, or pull the sealing plug 4 out of the thrust chamber 1 through the operating handle 6. This makes the installation and disassembly of the airtightness testing device faster, which is conducive to improving the efficiency of the liquid launch vehicle assembly and testing and shortening the preparation time before the rocket launch.

[0051] Example 7

[0052] Please see Figure 7 In this embodiment, the operating handle 6 includes a support rod 61 and an operating part 62 disposed at the end of the support rod 61. The support rod 61 is partially inserted into the through hole 44 of the sealing plug 4 to support the sealing plug 4. The operator applies external force to the operating part 62, and the support rod 61 transmits the external force to the sealing plug 4 to install or remove the sealing plug 4.

[0053] Optionally, the fixing component 7 includes a first fixing ring 71 sleeved on the support rod 61, a second fixing ring 72 sleeved on the sealing plug 4, and a plurality of fixing screws 73 for fixing the first fixing ring 71 and the second fixing ring 72. The surface of the second limiting part 43 is recessed inward to form a fixing groove 431 for installing the second fixing ring 72. By installing the second fixing ring 72 in the fixing groove 431 of the second limiting part 43, the first fixing ring 71 and the second fixing ring 72 are both evenly provided with threaded holes for threaded connection with the plurality of fixing screws 73 along their circumference. The first fixing ring 71 and the second fixing ring 72 are threadedly connected by the plurality of fixing screws 73, thereby fixing the sealing plug 4 and the operating handle 6. The structure is simple and easy to assemble and disassemble.

[0054] Example 8

[0055] Please refer to further information. Figure 7 In this embodiment, the surface of the operating part 62 of the operating handle 6 is provided with an anti-slip structure 621, which can effectively increase the friction between the operator's hand and the operating part 62, making it easier for the operator to operate.

[0056] Example 9

[0057] Please refer to the following: Figure 1 , Figure 2 , Figure 3 and Figure 5 In this embodiment, a limiting ring 3 for restricting the movement of the operating handle 6 is fitted on the air intake pipe 51 of the air intake assembly 5. The surface of the air intake pipe 51 is recessed inward to form a first limiting groove 513 for the limiting ring 3 to be inserted. By providing a first limiting groove 513 for installing the limiting ring 3 on the air intake pipe 51, the operator can quickly install the limiting ring 3 to a preset position on the air intake pipe 51. Fitting the limiting ring 3 in the first limiting groove 513 of the air intake pipe 51 can limit the movement range of the operating handle 6 relative to the air intake pipe 51, prevent the operating handle 6 from slipping off the air intake pipe 51, and improve the user experience.

[0058] Example 10

[0059] Please refer to further information. Figure 3 and Figure 5In this embodiment, the surface of the air intake pipe 51 is recessed inward to form a second limiting groove 514 for inserting the limiting ring 3. The first limiting groove 513 and the second limiting groove 514 are spaced apart. The second limiting groove 514 is located on the side of the first limiting groove 513 facing the sealing plug 4. By providing the second limiting groove 514 for inserting the limiting ring 3 on the surface of the air intake pipe 51, the operator can quickly install the limiting ring 3 into a preset position on the air intake pipe 51. By fitting the limiting ring 3 into the second limiting groove 514, the limiting ring 3 can restrict the operating handle 6 relative to the air intake pipe 51 when the airtightness detection device is in working condition. Displacement is generated to prevent the sealing plug 4 from losing support and detaching from the thrust chamber 1 due to operator error. When the airtightness test is completed, the limiting ring 3 is removed from the second limiting groove 514 and inserted into the first limiting groove 513, so that the operating handle 6 can move relative to the intake pipe 51 within the preset movement range, thereby pushing the support seat 52 away from the abutment groove 45 of the sealing plug 4, so that the sealing plug 4 loses the support and fixing effect of the support seat 52. The operator can pull the sealing plug 4 out of the thrust chamber 1 by pulling the operating handle 6, thereby completing the removal of the airtightness test device from the engine, which helps to improve the structural stability and reliability of the airtightness test device.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A gas tightness testing device for testing the sealing performance of a thrust chamber of a liquid rocket engine, the thrust chamber comprising a cavity and a Laval nozzle fixedly connected to the cavity, the Laval nozzle communicating between the interior and exterior of the cavity, the Laval nozzle having a narrow throat; characterized in that, The airtightness detection device includes: Air tightness detector; An air intake assembly includes a hollow air intake pipe and a support base. One end of the air intake pipe is fixedly connected to the support base, and the other end is provided with an external interface for connecting the air tightness detector. The support base is provided with a clearance hole for connecting the air intake pipe and the cavity. The outer diameter of the support base is smaller than the inner diameter of the narrow throat. The sealing plug is elastic and includes an arc portion adapted to the narrow throat, and a first limiting portion and a second limiting portion respectively disposed on opposite sides of the arc portion. The sealing plug is provided with a through hole for the air intake pipe to pass through. The through hole is located on the inner side wall of the first limiting portion and is recessed inward to form an abutment groove for restricting the movement of the support. The end of the air intake pipe is provided with a mounting part for fixing the support base. The outer surface of the mounting part is recessed inward to form a sealing groove for installing a sealing ring. The sealing ring is fitted into the sealing groove of the mounting part to seal the gap between the sealing plug and the air intake pipe. When it is necessary to perform an airtightness test on the thrust chamber of the engine, the support of the intake assembly is pushed away from the abutment groove of the sealing plug. The outer diameter of the support is smaller than the inner diameter of the narrow throat. The support is then inserted into the cavity of the thrust chamber through the narrow throat of the thrust chamber. The sealing plug is elastically deformed, and the first limiting part loses the support of the support seat. The first limiting part is squeezed by external force to pass through the narrow throat and extend into the cavity of the thrust chamber, so that the surface of the arc part of the sealing plug is tightly fitted with the inner wall of the narrow throat. By pulling the intake pipe, the support seat fixedly connected to the end of the intake pipe is placed into the abutment groove on the sealing plug, which supports and fixes the sealing plug and prevents the sealing plug from slipping off the thrust chamber. The air tightness detector is connected to the external interface of the air intake pipe to detect the gas flowing through the hollow air intake pipe and the clearance hole of the support seat into the thrust chamber, thereby pressurizing the inside of the chamber. Under the action of gas pressure, the gas pressure in the thrust chamber acts on the support seat, and the support seat is forced to compress the sealing plug. The sealing plug undergoes elastic deformation, and the first limiting part fits tightly against the inner wall of the thrust chamber to play the role of sealing and detecting gas.

2. The airtightness detection device as described in claim 1, characterized in that: The support base includes a support portion and a connecting portion fixedly connected to the end of the air intake pipe. The support portion is frustum-shaped and has a clearance hole through it. The inner and outer diameters of the support portion gradually decrease from the end away from the connecting portion toward the end closer to the connecting portion. The inner diameter of the abutment groove gradually decreases from the side away from the arc portion toward the side closer to the arc portion. The outer surface of the support portion and the inner wall of the abutment groove are fitted together.

3. The airtightness detection device as described in claim 2, characterized in that: The mounting part is provided with a mounting hole for the connecting part to be inserted, the inner sidewall of the mounting hole is provided with an internal thread, and the surface of the connecting part is provided with an external thread that matches the internal thread.

4. The airtightness detection device according to any one of claims 1 to 3, characterized in that: The circumferential sidewall of the first limiting part is provided with a sealing protrusion that abuts against the inner wall of the cavity.

5. The airtightness detection device according to any one of claims 1 to 3, characterized in that: The airtightness detection device also includes a fixing component and an operating handle sleeved on the air inlet pipe. The fixing component is used to fix the operating handle and the sealing plug.

6. The airtightness detection device according to claim 5, characterized in that: The operating handle includes a support rod and an operating part disposed at the end of the support rod. The fixing assembly includes a first fixing ring sleeved on the support rod, a second fixing ring sleeved on the sealing plug, and a plurality of fixing screws for fixing the first fixing ring and the second fixing ring. The surface of the second limiting part is recessed inward to form a fixing groove for installing the second fixing ring.

7. The airtightness detection device as described in claim 6, characterized in that: The surface of the operating part is provided with an anti-slip structure.

8. The airtightness detection device as described in claim 5, characterized in that: The air intake pipe is fitted with a limiting ring to restrict the movement of the operating handle, and the surface of the air intake pipe is recessed inward to form a first limiting groove for the limiting ring to be inserted.

9. The airtightness detection device as described in claim 8, characterized in that: The surface of the air intake pipe is recessed inward to form a second limiting groove for the limiting ring to be inserted. The first limiting groove and the second limiting groove are spaced apart, and the second limiting groove is located on the side of the first limiting groove facing the sealing plug.

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