Helium mass spectrum leak detection system and leak detection method for pipe fitting
By employing a dual-seal structure and a uniform helium filling design, the problem of insufficient sealing reliability in helium testing of tubular workpieces is solved, achieving efficient and accurate helium testing results and ensuring reliable and blind-spot-free testing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-03
- Publication Date
- 2026-03-13
AI Technical Summary
In existing technologies, the sealing reliability of tubular workpieces during helium testing is insufficient. Single-seal structures are prone to failure due to defects or wear, affecting testing efficiency and accuracy, especially in high-pressure or pressure-fluctuating environments where leakage is more likely.
It adopts a double-seal structure, including upper and lower gaskets and sealing rings for the workpiece, which, together with the positioning mold and helium shroud, form a helium filling chamber. Helium is uniformly filled through guide holes and guide grooves, and the coordinated design of pressure rod and spring provides balanced clamping force to ensure reliable sealing.
It achieves absolute isolation between the workpiece cavity and the outside, avoids misjudgment caused by sealing leakage, improves the accuracy and efficiency of leak detection results, and has no blind spots in detection, achieving axial and radial sealing simultaneously.
Smart Images
Figure CN121655797A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of helium detection, specifically a helium mass spectrometry leak detection system and method for pipe fittings. Background Technology
[0002] Many tubular workpieces are used in complex environments with high pressure, high temperature, and corrosive conditions. Even a tiny defect completely invisible to the naked eye can lead to leakage during long-term operation. Therefore, leak detection is necessary before tubular workpieces leave the factory. For tubular workpieces, during helium testing, a temporary reliable seal needs to be established at both ends of the tube. Helium gas is then introduced into the tube to check if helium can be detected inside, thus determining if a leak exists. Currently, the commonly used helium testing sealing method in the industry involves placing gaskets or sealing rings at both ends of the tube to form a sealing barrier. However, during testing, relying on only one seal means that any minor flaw in the seal, improper installation, or manufacturing errors, aging, or wear of the gasket / sealing ring itself can cause seal failure. Once this seal is breached, it will directly cause a large leakage of helium, leading to leak detection failure, a high false positive rate, and severely affecting testing efficiency and the accuracy of results. Especially when the testing pressure is high or there are pressure fluctuations, the single-seal structure has limited pressure-bearing capacity and is more prone to leakage. Due to the limitations of the tubular workpiece shape, only one type of sealing method, either a gasket or a sealing ring, can typically be used to seal the nozzle. Therefore, existing helium detection methods based on a single seal still have shortcomings in sealing reliability, which urgently need to be addressed. Summary of the Invention
[0003] To avoid and overcome the technical problems existing in the prior art, this invention provides a helium mass spectrometry leak detection system and method for tubular components. This invention significantly improves the sealing reliability of helium testing for tubular workpieces.
[0004] To achieve the above objectives, the present invention provides the following technical solution: A helium mass spectrometry leak detection system for pipe fittings includes a base. The top of the base has a three-section stepped columnar positioning cavity with a diameter that gradually widens from bottom to top. The bottom surface of the narrow diameter section of the positioning cavity is provided with a workpiece lower gasket for supporting the lower opening of the workpiece to be tested. A positioning mold coaxially sleeved on the outer ring of the workpiece to be tested is installed in the middle diameter section of the positioning cavity. The top and bottom of the positioning mold are respectively provided with an upper sealing ring and a lower sealing ring coaxially arranged with the workpiece to be tested. It also includes a helium shroud coaxially mounted outside the positioning mold from top to bottom. The helium shroud and the positioning mold form a sealed helium-filling cavity. There is an annular gap between the positioning mold and the tube body of the workpiece to be tested. The surface of the positioning mold is provided with guide holes to allow the annular gap to communicate with the helium-filling cavity. After being driven by a power source, the pressure rod slides along the axis of the workpiece to be tested and is in slidable engagement with the helium shroud. The pressing end of the pressure rod is provided with a gasket groove along the axis for installing the gasket on the workpiece. The diameter of the gasket groove is not less than the diameter of the workpiece to be tested. The pressure rod presses the gasket on the workpiece against the upper tube opening of the workpiece to be tested. The pressing end of the pressure rod corresponds to the position of the sealing ring on the workpiece. The pressure rod applies a pressing force to both the workpiece to be tested and the positioning mold from top to bottom. After the upper and lower sealing rings of the workpiece are deformed by the pressing, they seal the annular gap between the positioning mold and the tube body of the workpiece to be tested. The tube cavity of the workpiece to be tested is connected to the leak detection valve.
[0005] As a further aspect of the present invention: one end of the pressure rod located outside the helium shroud is fixed to the pressure plate, and the pressure plate is driven by a power source to move along the axial direction of the workpiece to be tested; a spring is coaxially arranged on the rod body located outside the helium shroud, and the two ends of the spring abut against and are positioned with the helium shroud and the pressure plate, respectively.
[0006] As a further embodiment of the present invention: spring grooves are provided on the opposing surfaces of the helium shield and the pressure plate to position the springs, and the power source is a telescopic rod, the driving end of which is fixedly connected to the pressure plate.
[0007] As a further aspect of the present invention: at least two sets of staggered mounting grooves are provided at the contact surface between the helium cover and the pressure rod for fixing the pressure rod sealing ring, and the helium cover and the pressure rod are sealed by the pressure rod sealing rings.
[0008] As a further embodiment of the present invention: a pressure plate is formed by radially protruding outer ring of the positioning mold and arranged coaxially with the positioning mold, the outer diameter of the pressure plate corresponding to the inner diameter of the wide diameter section of the positioning cavity; the bottom of the helium cover is open, and the opening is sealed to the pressure plate by a mold sealing ring.
[0009] As a further aspect of the present invention: a spring top pin is provided in the wide diameter section of the positioning cavity, and the spring top pin applies an elastic supporting force from bottom to top to the pressure plate along the axial direction parallel to the positioning mold; a limit baffle is provided on the upper surface of the base, and the movement trajectory of the limit baffle intersects with that of the pressure plate to limit the maximum rising height of the pressure plate.
[0010] As a further aspect of the present invention: a leak detection channel is provided on the base along the axial direction, and the leak detection valve is connected to the cavity of the workpiece to be tested through the leak detection channel.
[0011] As a further embodiment of the present invention: the base, the helium hood, and the power source are all located in the detection chamber, and a set of fans are respectively installed on the two opposite side walls of the detection chamber for convection ventilation; the helium hood is connected to the helium source through a pipeline.
[0012] As a further embodiment of the present invention: the positioning mold is provided with guide holes evenly distributed along the circumference, and the inner wall of the positioning mold is provided with guide grooves along the vertical direction, and the guide grooves and guide holes intersect each other.
[0013] A leak detection method for a helium mass spectrometry leak detection system for pipe fittings, characterized by comprising the following steps: S1. Insert the workpiece to be tested and the positioning mold into the positioning cavity of the base in sequence; S2. Start the telescopic rod. While pressing down the pressure plate, the pressure rod moves downward until it simultaneously presses and fixes the workpiece to be tested and the positioning mold. The gaskets at both ends of the workpiece to be tested form the first sealing surface at the opening of the workpiece to be tested, and the sealing rings at both ends of the positioning mold form the second sealing surface at the opening of the workpiece to be tested. As the pressure rod moves downward, the helium cover is pressed down synchronously by the spring. S3. Vacuum the workpiece to be tested to check for major leaks; S4. Fill the helium filling chamber with helium gas through the helium shroud and activate the leak detection valve; If the leak detection valve detects the presence of helium gas in the cavity of the workpiece under test, it indicates that the workpiece under test is leaking. If the leak detection valve detects that there is no helium gas in the cavity of the workpiece under test, it indicates that there is no leak in the workpiece under test. S5. After purging and removing helium, the test is completed. The workpiece to be tested is then removed and placed in its proper categories.
[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention forms a first axial seal by setting upper and lower gaskets at the upper and lower openings of the workpiece to be tested; simultaneously, it forms a second radial seal by setting upper and lower sealing rings at the upper and lower ends of the positioning mold, which fit tightly against the outer wall of the workpiece tube. The two independent sealing structures work together, so even if one seal has a slight leakage due to installation defects or damage, the other seal can still effectively isolate it, ensuring absolute isolation between the workpiece tube cavity and the external environment. This fundamentally avoids misjudgment in helium testing due to seal leakage, significantly improves the accuracy and reliability of leak detection results, and enhances the sealing reliability in the helium testing process.
[0015] 2. This invention uses a positioning mold and a helium shroud to form a helium-filling cavity. Through the guide holes and channels on the positioning mold, helium gas can quickly and evenly fill the annular gap between the positioning mold and the workpiece tube, rapidly exposing the entire outer surface of the workpiece to the detection helium gas. If a leak occurs anywhere on the workpiece tube, helium gas can immediately seep into the cavity and be detected, achieving simultaneous leak detection of the workpiece tube without blind spots, greatly improving detection efficiency.
[0016] 3. Through the coordinated design of the pressure rod and the spring, when the power source drives the pressure plate to press down, the spring can provide a buffered and uniform clamping force. This clamping force acts on the gasket and the sealing ring on the workpiece simultaneously through the pressure rod, realizing the synchronous and balanced clamping of axial and radial seals. This ensures that the sealing ring is fully deformed to form an effective seal, and also prevents damage to the workpiece opening or body due to excessive pressure.
[0017] 4. This invention enables one-button clamping and sealing via a power source such as a telescopic rod. A single clamping operation automatically completes the clamping of all sealing rings and the sealing of the helium filling chamber. Combined with the convection fan setup in the testing chamber, residual helium can be quickly purged after each test, preparing for the next test.
[0018] 5. The three-section stepped columnar positioning cavity of this invention cooperates with the pressure plate of the positioning mold, combined with the elastic support of the spring top pin and the hard limit of the limiting baffle, to ensure that the positioning mold and the workpiece to be tested can be quickly and accurately positioned on the central axis, thus realizing rapid positioning and guiding function. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the structure of the present invention.
[0020] Figure 2 This is an enlarged view of the structure of the base in this invention.
[0021] Figure 3 This is a schematic diagram of the positioning mold in this invention.
[0022] In the picture: 1. Base; 11. Leak detection channel; 12. Workpiece lower gasket; 13. Workpiece lower sealing ring; 14. Spring top pin; 15. Positioning cavity; 16. Limiting baffle; 2. Helium shroud; 21. Helium filling chamber; 22. Pressure rod sealing ring; 23. Spring groove; 24. Mold sealing ring; 3. Positioning mold; 31. Pressure plate; 32. Sealing ring on the workpiece; 33. Flow guide hole; 34. Flow guide groove; 4. Pressure bar; 41. Shim on workpiece; 5. Pressure plate; 51. Spring; 6. Fan; 7. Telescopic rod; 8. Leak detection valve; 9. Workpiece to be tested; 10. Testing chamber. Detailed Implementation
[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0024] Please see Figures 1-3 In this embodiment of the invention, a helium mass spectrometry leak detection system and leak detection method for a pipe fitting are disclosed. The workpiece to be tested 9 is a tubular workpiece with open ends. The leak detection system includes a detection chamber 10 and a base 1 disposed in the detection chamber 10.
[0025] The base 1 is fixed inside the testing chamber 10, with an opening at the top to form a positioning cavity 15. The positioning cavity 15 is a three-section stepped cylindrical cavity with a diameter that gradually widens from bottom to top. The innermost narrow diameter section of the cavity is used to fix the workpiece 9 to be tested. The upper and lower sides of the workpiece 9 are respectively provided with an upper workpiece shim 41 and a lower workpiece shim 12, and the lower workpiece shim 12 corresponds to the inner diameter of the narrow diameter section of the positioning cavity 15.
[0026] A positioning mold 3 is installed in the middle diameter section of the positioning cavity 15. The positioning mold 3 is coaxially sleeved on the outer ring of the workpiece 9 to be tested. An upper sealing ring 32 and a lower sealing ring 13 are respectively provided at its top and bottom to form a seal with the tube body of the workpiece 9 during compression deformation. The length of the positioning mold 3 preferably corresponds to the length of the workpiece 9 to be tested, and the upper and lower sealing rings 32 and 13 correspond to the upper and lower ends of the tube body of the workpiece 9, respectively. A pressure plate 31 is formed by radially protruding from the outer ring of the positioning mold 3. The pressure plate 31 is coaxially arranged with the positioning mold 3, and its outer diameter corresponds to the inner diameter of the wide diameter section of the positioning cavity 15. A mold sealing ring 24 is provided at the bottom opening of the helium cover 2, and is sealed to the pressure plate 31. A spring top pin 14 is provided in the wide diameter section of the positioning cavity 15 to apply an elastic supporting force from bottom to top to the pressure plate 31. The upper surface of the base 1 is provided with a limiting baffle 16, which is used to limit the maximum rising height of the pressure plate 31 and prevent the positioning mold 3 from coming out.
[0027] The helium shroud 2 has an opening at the bottom and is coaxially mounted on the outside of the positioning mold 3 from top to bottom, forming a sealed helium-filling cavity 21 between them. An annular gap exists between the positioning mold 3 and the tube body of the workpiece 9 to be tested. A guide hole 33 on the surface of the positioning mold 3 connects this annular gap to the helium-filling cavity 21. The helium shroud 2 is connected to an external helium source via a pipeline to fill the helium-filling cavity 21 with helium. Guide holes 33 are evenly distributed circumferentially on the positioning mold 3, and guide grooves 34 are formed vertically on its inner wall. The guide grooves 34 intersect with the guide holes 33, ensuring uniform distribution of helium within the annular gap and improving detection accuracy. To ensure a tight seal between the helium shroud 2 and the pressure rod 4, multiple sets of staggered mounting grooves are formed at the contact surface between the helium shroud 2 and the pressure rod 4 to fix the pressure rod sealing ring 22, forming a multi-layered seal.
[0028] The entire system is housed within the testing chamber 10, which has fans 6 installed on its two opposite side walls for convection ventilation, ensuring a stable testing environment. The helium hood 2 is connected to a helium source via piping for automatic helium filling.
[0029] The pressure rod 4 is driven by the telescopic rod 7 and slides along the axis of the workpiece 9 to be tested, engaging with the helium shield 2. The pressing end of the pressure rod 4 has a gasket groove along its axial direction. The diameter of the gasket groove is not less than the diameter of the workpiece 9 to be tested, allowing the gasket 41 on the workpiece with a diameter larger than the workpiece 9 to be inserted into the gasket groove and move synchronously with the pressure rod 4. The outer ring of the gasket groove of the pressure rod 4 forms the pressing end, corresponding to the position of the sealing ring 32 on the workpiece, so that the pressure rod 4 can simultaneously apply a clamping force to both the workpiece 9 to be tested and the positioning mold 3 when it presses down. Under the action of the clamping force, the upper sealing ring 32 and the lower sealing ring 13 of the workpiece deform, sealing both ends of the annular gap between the positioning mold 3 and the workpiece 9 to be tested.
[0030] To optimize the clamping process, one end of the pressure rod 4, located outside the helium shroud 2, is fixed to the pressure plate 5. The pressure plate 5 is driven by the telescopic rod 7 to move axially along the workpiece 9 to be tested. A spring 51 is coaxially arranged on the rod body of the pressure rod 4 outside the helium shroud 2. Both ends of the spring 51 abut against and are positioned with respect to the helium shroud 2 and the pressure plate 5, respectively, to provide buffering and pressure equalization. Spring grooves 23 are provided on the opposing surfaces of the helium shroud 2 and the pressure plate 5 to position the ends of the springs 51.
[0031] A leak detection channel 11 is formed along the axial direction on the base 1. The leak detection valve 8 sequentially detects the leaks through the channel 11 and the hole in the center of the workpiece lower gasket 12 before connecting to the cavity of the workpiece 9 to be tested for helium detection. The system also includes a vacuuming mechanism, the location of which is not limited. A three-way valve can be installed at the opening of the leak detection channel 11 to selectively connect the cavity of the workpiece 9 to either the vacuuming mechanism or the leak detection valve 8. Alternatively, an axial hole can be formed on the pressure rod 4, through which the vacuuming mechanism can be connected to the cavity of the workpiece 9.
[0032] The specific testing process includes the following steps: Includes the following steps: S1. Insert the workpiece 9 to be tested and the positioning mold 3 into the positioning cavity 15 of the base 1 in sequence; S2. Start the telescopic rod. While pressing down the pressure plate 5, the pressure rod 4 moves downward until the pressure rod 4 simultaneously presses and fixes the workpiece 9 to be tested and the positioning mold 3. The gaskets at both ends of the workpiece 9 to be tested form the first sealing surface at the opening of the workpiece 9 to be tested, and the sealing rings at both ends of the positioning mold 3 form the second sealing surface at the opening of the workpiece 9 to be tested. While the pressure rod 4 moves downward, the helium cover 2 is pressed down synchronously by the spring 51. S3. Vacuum the workpiece to be tested to check for major leaks; S4. Fill helium gas into the helium filling chamber 21 through the helium shroud 2 and activate the leak detection valve 8; If the leak detection valve 8 detects the presence of helium gas in the cavity of the workpiece 9 under test, it indicates that the workpiece 9 under test is leaking. When the leak detection valve 8 detects that there is no helium gas in the cavity of the workpiece 9 under test, it indicates that the workpiece 9 under test has no leakage. S5. After purging and removing helium, the test is completed. The workpiece 9 to be tested is removed and placed in its proper categories. The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.
[0033] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.
Claims
1. A helium mass spectrometry leak detection system for pipe fittings, characterized in that, The base (1) has a three-section stepped columnar positioning cavity (15) with a diameter that gradually widens from bottom to top. The bottom surface of the narrow diameter section of the positioning cavity (15) is provided with a workpiece lower gasket (12) for supporting the lower opening of the workpiece (9) to be tested. The positioning mold (3) is installed in the middle diameter section of the positioning cavity (15) and is coaxially sleeved on the outer ring of the workpiece (9) to be tested. The top and bottom of the positioning mold (3) are respectively provided with a workpiece upper sealing ring (32) and a workpiece lower sealing ring (13) arranged coaxially with the workpiece (9) to be tested. It also includes a helium shroud (2) coaxially mounted outside the positioning mold (3) from top to bottom. The helium shroud (2) and the positioning mold (3) enclose a sealed helium-filling cavity (21). There is an annular gap between the positioning mold (3) and the tube body of the workpiece (9) to be tested. The surface of the positioning mold (3) is provided with a guide hole (33) to allow the annular gap to communicate with the helium-filling cavity (21). After being driven by the power source, the pressure rod (4) slides along the axial direction of the workpiece (9) to be tested and engages with the helium shroud (2). The pressing end of the pressure rod (4) is provided with a gasket groove along the axial direction for installing the gasket (41) on the workpiece. The diameter of the groove is not less than the diameter of the workpiece (9) to be tested. The pressure rod (4) presses the gasket (41) on the workpiece onto the upper pipe opening of the workpiece (9) to be tested. The pressing end of the pressure rod (4) corresponds to the position of the sealing ring (32) on the workpiece. The pressure rod (4) applies a pressing force to the workpiece (9) to be tested and the positioning mold (3) from top to bottom at the same time. After the upper sealing ring (32) and the lower sealing ring (13) of the workpiece are compressed and deformed, an annular gap is sealed between the positioning mold (3) and the tube body of the workpiece (9) to be tested. The tube cavity of the workpiece (9) to be tested is connected to the leak detection valve (8).
2. The helium mass spectrometry leak detection system for pipe fittings according to claim 1, characterized in that, One end of the pressure rod (4) located outside the helium cover (2) is fixed on the pressure plate (5). The pressure plate (5) is driven by a power source to move along the axis of the workpiece (9) to be tested. A spring (51) is arranged coaxially on the rod body of the pressure rod (4) located outside the helium cover (2). The two ends of the spring (51) are respectively positioned against the helium cover (2) and the pressure plate (5).
3. The helium mass spectrometry leak detection system for pipe fittings according to claim 2, characterized in that, Spring grooves (23) are provided on the opposite surfaces of the helium shield (2) and the pressure plate (5) to position the spring (51). The power source is a telescopic rod (7), and the driving end of the telescopic rod (7) is fixedly connected to the pressure plate (5).
4. The helium mass spectrometry leak detection system for pipe fittings according to claim 1, characterized in that, At least two sets of staggered mounting grooves are provided at the contact surface between the helium cover (2) and the pressure rod (4) for fixing the pressure rod sealing ring (22). The helium cover (2) and the pressure rod (4) are sealed by each pressure rod sealing ring (22).
5. A helium mass spectrometry leak detection system for pipe fittings according to claim 1, characterized in that, The outer ring of the positioning mold (3) is radially protruded to form a pressure plate (31) coaxially arranged with the positioning mold (3). The outer diameter of the pressure plate (31) corresponds to the inner diameter of the wide diameter section of the positioning cavity (15). The bottom of the helium cover (2) is open, and the opening is sealed with the pressure plate (31) through the mold sealing ring (24).
6. A helium mass spectrometry leak detection system for pipe fittings according to claim 5, characterized in that, A spring top pin (14) is provided in the wide diameter section of the positioning cavity (15). The spring top pin (14) applies an elastic support force from bottom to top to the pressure plate (31) along the axial direction of the parallel positioning mold (3). A limit baffle (16) is provided on the upper surface of the base (1). The movement trajectory of the limit baffle (16) and the pressure plate (31) intersect to limit the maximum rising height of the pressure plate (31).
7. The helium mass spectrometry leak detection system for pipe fittings according to claim 1, characterized in that, A leak detection channel (11) is provided on the base (1) along the axial direction. The leak detection valve (8) is connected to the cavity of the workpiece (9) to be tested through the leak detection channel (11).
8. A helium mass spectrometry leak detection system for pipe fittings according to claim 1, characterized in that, The base (1), helium hood (2) and power source are all located in the testing chamber (10). A set of fans (6) are installed on the two opposite side walls of the testing chamber (10) for convection ventilation. The helium hood (2) is connected to the helium source through a pipeline.
9. A helium mass spectrometry leak detection system for pipe fittings according to claim 1, characterized in that, The positioning mold (3) has uniformly opened guide holes (33) along the circumferential direction, and the inner wall of the positioning mold (3) has opened guide grooves (34) along the vertical direction, and each guide groove (34) intersects with the guide hole (33).
10. A leak detection method for a helium mass spectrometry leak detection system for pipe fittings according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Insert the workpiece to be tested (9) and the positioning mold (3) into the positioning cavity (15) of the base (1) in sequence; S2. Start the telescopic rod and press down the pressure plate (5) at the same time, drive the pressure rod (4) down until the pressure rod (4) simultaneously presses and fixes the workpiece (9) to be tested and the positioning mold (3). The gaskets at both ends of the workpiece (9) to be tested form the first sealing surface at the opening of the workpiece (9) to be tested, and the sealing rings at both ends of the positioning mold (3) form the second sealing surface at the opening of the workpiece to be tested. At the same time as the pressure rod (4) moves down, the helium cover (2) is pressed down synchronously by the spring (51). S3. Vacuum test on the workpiece (9) to check for major leaks; S4. Fill helium into the helium filling chamber (21) through the helium shroud (2) and start the leak detection valve (8). When the leak detection valve (8) detects the presence of helium in the cavity of the workpiece (9) to be tested, it indicates that there is a leak in the workpiece (9); When the leak detection valve (8) detects that there is no helium in the cavity of the workpiece (9) to be tested, it indicates that there is no leakage in the workpiece (9); S5. After purging helium, complete the test, take out the workpiece to be tested (9) and place it in categories.