Vacuum helium mass spectrometry leak detection method and device for bellows products

Abstract

The present invention provides a vacuum helium mass spectrometer leak detection method and device for bellows products, comprising the following steps: step S1, fixing the bellows with a support ring; step S2, assembling the support ring with a support plate; step S3, placing a first O-ring seal between the bellows and the upper cover, and fixing the upper cover, the bellows, and the support plate with studs; step S4, placing the fixed bellows on a base, placing a second O-ring seal between the base and the upper cover, and fixing them with bolts; step S5, placing the assembled bellows vertically, connecting a helium mass spectrometer leak detector to the bottom sampling port, and evacuating the outside of the bellows; step S6, connecting a helium cylinder connected to a pressure reducing valve to the top helium filling port, and filling the bellows with helium for leak rate testing. The present invention ensures that the bellows will not be stretched or distorted under stamping conditions; ensures the effectiveness of the seal between the bellows and the upper cover; and provides accurate and reliable test results.

Description

Technical Field

[0001] The present invention relates to the field of experiment and testing, and in particular to a vacuum helium mass spectrometry leak detection method and device for bellows products. Background Art

[0002] Bellows are key components in launch vehicle booster and delivery systems, typically consisting of dozens of diaphragms welded to a cover and base. Helium mass spectrometry leak rate is a crucial performance indicator for bellows. However, since bellows are elastic components, effective sealing is difficult. Furthermore, they are prone to distortion and stretching when pressurized, compromising product quality. Therefore, vacuum helium mass spectrometry leak rate testing of bellows is challenging.

[0003] The existing Chinese patent publication number CN212030845U discloses a helium mass spectrometer leak detection device for a bellows assembly, which includes a bellows assembly to be tested, an O-ring, a bellows inner support block, and upper and lower sealing flanges. The technical key points are: the outer circle of the upper sealing flange is clamped on the step on the inner side of the upper flange of the bellows assembly, an upper O-ring is provided at the edge of the upper sealing flange and the bellows inner support block, the connecting screws of the upper sealing flange are connected to the bellows inner support block, and the support block also has a bellows inner cavity channel; a lateral leak hole is provided on the upper flange of the bellows assembly, and the lateral leak hole is connected to the inner cavity of the bellows assembly; a lower sealing flange is sleeved on the lower part of the support block, and the outer edge of the lower sealing flange is set in an annular groove on the lower flange through a lower O-ring.

[0004] Currently, in the production of bellows, helium mass spectrometry leak rate checks are typically not performed on the bellows while they are still in place. Instead, testing is performed on the assembly after the bellows shell is welded. With this approach, if the bellows leak rate exceeds the specified value, the entire assembly must be scrapped, resulting in significant waste in production costs, time, manpower, and material resources.

[0005] In view of the above situation, it is urgent to develop a vacuum helium mass spectrometry leak detection method for bellows products. Combined with the structural characteristics of the bellows, effective sealing can be achieved while preventing the bellows from deforming, thereby solving the problem of vacuum helium mass spectrometry leak detection for bellows products. Summary of the Invention

[0006] In view of the defects in the prior art, the purpose of the present invention is to provide a vacuum helium mass spectrometry leak detection method and device for bellows products.

[0007] A vacuum helium mass spectrometry leak detection method for bellows products provided by the present invention comprises the following steps:

[0008] Step S1, fixing the bellows with a support ring;

[0009] Step S2, assembling the support ring and the support plate;

[0010] Step S3: Place a first O-ring for sealing between the bellows and the upper cover, and fix the upper cover, the bellows, and the support plate with studs;

[0011] Step S4: Place the fixed bellows on the base, place a second O-ring seal between the base and the upper cover, and secure with bolts;

[0012] Step S5: Place the assembled bellows vertically, connect a helium mass spectrometer leak detector to the bottom inspection port, and evacuate the outside of the bellows;

[0013] Step S6: Connect the helium cylinder connected to the pressure reducing valve to the top helium filling port, and fill the bellows with helium to perform a leak rate check.

[0014] Preferably, in step S1, the height of the support ring matches the height of the bellows, the top end of the support ring extends inward to form a support portion for supporting the bellows, the support portion is inserted into the uppermost corrugation of the bellows, the profile of the support portion matches the bellows, the sharp edges are rounded, the surface roughness is not less than the surface roughness of the bellows, and the length of the support portion extending into the bellows is within 30%-50% of the width of the corrugation.

[0015] Preferably, in step S1, the support ring includes two semicircular support rings, and the semicircular support rings are obtained by integral turning and then linear cutting along a diameter line, with a cutting line width of ≤0.5 mm.

[0016] Preferably, in step S1, 8-10 ventilation grooves are uniformly distributed along the circumferential direction on the side wall of the support ring, and the height of the ventilation grooves is within 40%-60% of the height of the support ring.

[0017] Preferably, in step S2, the bottom end of the support ring is inserted into a slot on the upper surface of the support plate, and the fitting tolerance between the outer diameter of the support ring and the outer diameter of the slot is 0-0.10 mm.

[0018] Preferably, in step S2, the bottom end of the bellows is placed on a support plate, and the support plate has 6-8 ventilation grooves evenly distributed along the circumference, and the width of the ventilation grooves is 2-4 times the radial width of the contact portion between the support plate and the bellows.

[0019] Preferably, in step S3, a sealing groove for installing a first O-ring is provided on the upper cover, and the difference between the wire diameter of the first O-ring and the width of the sealing groove does not exceed 10% of the wire diameter, and the difference between the wire diameter and the height of the sealing groove is within 25%-35% of the wire diameter.

[0020] Preferably, in step S3, the stud is arranged on the outside of the support ring, the top end of the stud is first screwed to the upper cover and then welded, and the bottom end of the stud passes through the support plate and is fastened to the support plate by a first washer and a first nut.

[0021] Preferably, in step S4, the wire diameter of the second O-ring is larger than the wire diameter of the first O-ring, the lower surface of the upper cover is fitted to the upper surface of the base, a sealing groove for mounting the second O-ring is provided on the upper cover, the difference between the wire diameter of the second O-ring and the width of the sealing groove does not exceed 10% of the wire diameter, and the difference between the wire diameter and the height of the sealing groove is within 25%-35% of the wire diameter;

[0022] The bolt is arranged on the outside of the second O-ring, passes through the upper cover and the base and is fixed by the second washer and the second nut.

[0023] According to the present invention, a vacuum helium mass spectrometry leak detection device for bellows products is provided, which is applied to the vacuum helium mass spectrometry leak detection method for bellows products, comprising: an upper cover, a support ring, a support plate, and a base;

[0024] The support ring is arranged outside the bellows and the top end is connected to the bellows. The bottom end of the support ring is installed in the support plate. The bellows is placed on the support plate. The upper cover is fastened to the support plate by studs, and the upper cover is sealed with the bellows via a first O-ring.

[0025] The support plate is installed in the base, and the base is fastened to the upper cover by bolts and sealed by a second O-ring;

[0026] The helium filling port at the top of the bellows passes through the upper cover and is connected to the helium cylinder, and the sampling inspection port at the bottom of the bellows passes through the support plate and the base and is connected to the helium mass spectrometer leak detector.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention ensures the height of the bellows by adopting a support ring and a support plate, ensuring that the bellows will not be stretched or twisted under stamping conditions; the bellows and the upper cover are sealed by adopting multiple O-rings, studs, support rings and support plates, thereby ensuring the effectiveness of the seal between the bellows and the upper cover during the sealing process of the upper cover and the base; the studs and the upper cover are first screwed and then welded, effectively preventing welding deformation and ensuring assembly accuracy; the helium filling port is exposed to the air, which makes it easy to eliminate the problem of excessive leakage rate caused by poor sealing of the filling port; vacuum cover positive pressure helium mass spectrometry leak detection of bellows products is realized, and the detection results are accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0030] Figure 1 This is a schematic structural diagram of a vacuum helium mass spectrometer leak detection device for bellows products, which is mainly embodied in the present invention;

[0031] Figure 2 This is a schematic diagram mainly showing the connection between the bellows and the support ring of the present invention.

[0032] As shown in the figure: bellows 1; upper cover 2; support ring 3; support plate 4; base 5; stud 6; first washer 7; first nut 8; first O-ring 9; second O-ring 10; bolt 11; second washer 12; second nut 13. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0034] Example 1

[0035] like Figure 1 As shown, a vacuum helium mass spectrometry leak detection method for bellows products provided by the present invention includes the following steps:

[0036] Step S1, fixing the bellows 1 with a support ring 3;

[0037] Step S2, assembling the support ring 3 and the support plate 4;

[0038] Step S3: Place a first O-ring 9 between the bellows 1 and the upper cover 2 for sealing, and use studs 6 to fix the upper cover 2, the bellows 1, and the support plate 4;

[0039] Step S4: Place the fixed bellows 1 on the base 5, place a second O-ring 10 between the base 5 and the upper cover 2 for sealing, and fix them with bolts 11;

[0040] Step S5: Place the assembled bellows 1 vertically, connect a helium mass spectrometer leak detector to the bottom inspection port, and evacuate the outside of the bellows 1;

[0041] Step S6: Connect the helium cylinder connected to the pressure reducing valve to the top helium filling port, and fill the bellows 1 with helium to perform a leak rate check.

[0042] The vacuum helium mass spectrometry leak detection method for bellows products of the present application can effectively solve the problems of the difficulty in vacuum cover inspection of bellows products and the easy twisting and stretching deformation of bellows during the leak detection process, and the detection results are accurate and reliable.

[0043] like Figure 2 As shown, in step S1, the height of the support ring 3 matches the height of the bellows 1, that is, except for the portion of the support ring 3 that is inserted into the support plate 4, the height of the remaining portion is consistent with the product design height. The top of the support ring 3 extends inward to form a support portion for supporting the bellows 1. The support portion is inserted into the uppermost corrugation of the bellows 1. The profile of the support portion matches the bellows 1, that is, the profile of the contact portion between the support ring 3 and the bellows 1 should be consistent, and the sharp edges should be rounded, with a surface roughness not less than that of the bellows 1. The length of the support portion extending into the bellows 1 is controlled within the range of 30%-50% of the corrugation width. Preferably, the length of the support ring 3 extending into the bellows 1 is 40% of the corrugation width.

[0044] In step S1, the support ring 3 includes two semicircular support rings, which are obtained by integral turning and then linear cutting along the diameter line, with the cutting line width being ≤0.5 mm. Preferably, the cutting line width is 0.3 mm.

[0045] In step S1, 8-10 ventilation grooves are uniformly distributed along the circumference of the side wall of the support ring 3, and the length of the ventilation grooves is controlled within 40%-60% of the height of the support ring 3. Preferably, 10 ventilation grooves are opened, and the length of the ventilation grooves is 50% of the height of the support ring 3.

[0046] In step S2, the support ring 3 is assembled with the support plate 4, and the bottom end of the support ring 3 is inserted into the slot on the upper surface of the support plate 4. The fitting tolerance between the outer diameter of the support ring 3 and the outer diameter of the slot should be controlled within 0-0.10mm.

[0047] In step S2, the bottom end of the bellows 1 is placed on the support plate 4. The support plate 4 and the bellows 1 are provided with 6-8 ventilation grooves evenly distributed along the circumferential direction at the contact portion between the support plate 4 and the bellows 1. The width of the ventilation grooves is 2-4 times the radial width of the contact portion between the support plate 4 and the bellows 1. Preferably, 8 ventilation grooves are provided, and the width of the ventilation grooves is 3 times the radial width of the contact portion between the support plate 4 and the bellows 1.

[0048] In step S3, a first O-ring 9 is placed between the bellows 1 and the upper cover 2 for sealing. The upper cover 2 is provided with a sealing groove for receiving the first O-ring 9. The difference between the wire diameter of the first O-ring 9 and the width of the sealing groove does not exceed 10% of the wire diameter, and the difference between the wire diameter and the height of the sealing groove is within 25%-35% of the wire diameter. Preferably, the difference between the wire diameter of the first O-ring 9 and the width of the sealing groove is 8% of the wire diameter, and the difference between the wire diameter of the first O-ring 9 and the height of the sealing groove is 30% of the wire diameter.

[0049] In step S3, the stud 6 is set on the outside of the support ring 3, the top end of the stud 6 is first screwed to the upper cover 2 and then welded to the upper cover 2 as a whole by a welding method, and the bottom end of the stud 6 passes through the support plate 4 and is fastened to the support plate 4 through the first washer 7 and the first nut 8.

[0050] In step S4, the fixed bellows 1 is placed on the base 5. A second O-ring seal 10 is placed between the base 5 and the upper cover 2. The lower surface of the upper cover 2 is aligned with the upper surface of the base 5. The upper cover 2 is provided with a sealing groove for mounting the second O-ring 10. The wire diameter of the second O-ring 10 is larger than the wire diameter of the first O-ring 9. The difference between the wire diameter of the second O-ring 10 and the width of the sealing groove does not exceed 10% of the wire diameter, and the difference between the wire diameter and the height of the sealing groove is within 25%-35% of the wire diameter. Preferably, the difference between the wire diameter of the second O-ring 10 and the width of the sealing groove is 8% of the wire diameter, and the difference between the wire diameter of the second O-ring 10 and the height of the sealing groove should be 30% of the wire diameter.

[0051] In step S4 , the bolt 11 is disposed on the outside of the second O-ring 10 , passes through the upper cover 2 and the base 5 , and is fixed by the second washer 12 and the second nut 13 .

[0052] The present application adopts a support ring 3 and a support plate 4 to ensure the height of the bellows 1, ensuring that the bellows 1 will not be stretched or twisted under stamping conditions; the present application adopts multiple O-rings, studs 6, support rings 3 and support plates 4 to seal the bellows 1 and the upper cover 2, ensuring the effectiveness of the seal between the bellows 1 and the upper cover 2 during the sealing process of the upper cover 2 and the base 5; the studs 6 and the upper cover 2 of the present application are first screwed and then welded, which effectively prevents welding deformation and ensures assembly accuracy; the helium filling port of the present application is exposed to the air, which makes it easy to eliminate the problem of excessive leakage rate caused by poor sealing of the filling port; the present application realizes vacuum cover positive pressure helium mass spectrometry leak detection for bellows products, and the detection results are accurate and reliable.

[0053] Example 2

[0054] Based on Example 1, a vacuum helium mass spectrometer leak detection device for a bellows product provided according to the present invention includes: an upper cover 2, a support ring 3, a support plate 4, and a base 5; the support ring 3 is arranged on the outside of the bellows 1 and the top end is connected to the bellows 1, the bottom end of the support ring 3 is installed in the support plate 4, the bellows 1 is placed on the support plate 4, the upper cover 2 is fastened to the support plate 4 by studs 6, and the upper cover 2 is sealed to the bellows 1 by a first O-ring 9; the support plate 4 is installed in the base 5, the base 5 is fastened to the upper cover 2 by bolts 11 and is sealed by a second O-ring 10; the helium filling port at the top of the bellows 1 passes through the upper cover 2 to be connected to the helium cylinder, and the sampling port at the bottom of the bellows 1 passes through the support plate 4 and the base 5 to be connected to the helium mass spectrometer leak detector.

[0055] By using the device of the present application to perform vacuum helium mass spectrometry leak detection on bellows products, the bellows can be effectively prevented from being stretched, twisted, and deformed in a pressurized state. At the same time, reliable sealing of the bellows is achieved, and vacuum cover positive pressure helium mass spectrometry leak detection on bellows products is realized, with accurate and reliable detection results.

[0056] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and 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, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0057] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A vacuum helium mass spectrometry leak detection method for bellows products, characterized in that: The following steps are involved: Step S1, fixing the bellows (1) with a support ring (3), the support ring (3) comprising two semicircular support rings, 8-10 ventilation grooves being uniformly distributed along the circumference on the side wall of the support ring (3), the height of the support ring (3) matching the height of the bellows (1), the top end of the support ring (3) extending inward to form a support portion for supporting the bellows (1), the support portion being inserted into the uppermost corrugation of the bellows (1); Step S2, assembling the support ring (3) and the support plate (4), inserting the bottom end of the support ring (3) into the slot on the upper surface of the support plate (4), placing the bottom end of the bellows (1) on the support plate (4), and providing 6-8 ventilation grooves evenly distributed along the circumference of the support plate (4); Step S3, a first O-ring (9) is placed between the bellows (1) and the upper cover (2) for sealing, and the upper cover (2), the bellows (1) and the support plate (4) are fixed by a stud (6), the stud (6) is arranged on the outside of the support ring (3), the top end of the stud (6) is first screwed to the upper cover (2) and then welded, and the bottom end of the stud (6) passes through the support plate (4) and is fastened to the support plate (4) by a first washer (7) and a first nut (8); Step S4, placing the fixed bellows (1) on the base (5), placing a second O-ring (10) between the base (5) and the upper cover (2) for sealing, and fixing with bolts (11), wherein the wire diameter of the second O-ring (10) is larger than the wire diameter of the first O-ring (9), the lower surface of the upper cover (2) is fitted with the upper surface of the base (5), the bolts (11) are arranged on the outside of the second O-ring (10), and the bolts (11) pass through the upper cover (2) and the base (5) and are fixed by the second washer (12) and the second nut (13); Step S5, placing the assembled bellows (1) vertically, connecting a helium mass spectrometer leak detector to the bottom sampling port, and evacuating the outside of the bellows (1); Step S6: connect the helium cylinder connected to the pressure reducing valve to the top helium filling port, and fill the bellows (1) with helium to perform a leak rate check.

2. The vacuum helium mass spectrometry leak detection method for bellows products according to claim 1, characterized in that: In step S1, the profile of the support portion matches the corrugated tube (1), and the sharp edges are rounded, with a surface roughness not less than that of the corrugated tube (1), and the length of the support portion extending into the corrugated tube (1) is within 30%-50% of the corrugation width.

3. The vacuum helium mass spectrometry leak detection method for bellows products according to claim 1, characterized in that: In the step S1, the semicircular support ring is obtained by integral turning and then linear cutting along the diameter line, with the cutting line width being ≤0.5 mm.

4. The vacuum helium mass spectrometry leak detection method for bellows products according to claim 1, characterized in that: In step S1, the height of the ventilation groove is within 40%-60% of the height of the support ring (3).

5. The vacuum helium mass spectrometry leak detection method for bellows products according to claim 1, characterized in that: In step S2, the fitting tolerance between the outer diameter of the support ring (3) and the outer diameter of the slot is 0-0.10 mm.

6. The vacuum helium mass spectrometry leak detection method for bellows products according to claim 1, characterized in that: In step S2, the width of the ventilation groove is 2-4 times the radial width of the contact portion between the support plate (4) and the bellows (1).

7. The vacuum helium mass spectrometry leak detection method for bellows products according to claim 1, characterized in that: In step S3, a sealing groove for installing a first O-ring (9) is provided on the upper cover (2), the difference between the wire diameter of the first O-ring (9) and the width of the sealing groove does not exceed 10% of the wire diameter, and the difference between the wire diameter and the height of the sealing groove is within 25%-35% of the wire diameter.

8. The vacuum helium mass spectrometry leak detection method for bellows products according to claim 1, characterized in that: In step S4, a sealing groove for installing a second O-ring (10) is provided on the upper cover (2), and the difference between the wire diameter of the second O-ring (10) and the width of the sealing groove does not exceed 10% of the wire diameter, and the difference between the wire diameter and the height of the sealing groove is within 25%-35% of the wire diameter.

9. A vacuum helium mass spectrometry leak detection device for bellows products, applied to the vacuum helium mass spectrometry leak detection method for bellows products according to any one of claims 1 to 8, characterized in that: include: Upper cover (2), support ring (3), support plate (4), base (5); The support ring (3) is arranged outside the bellows (1) and the top end is connected to the bellows (1), the bottom end of the support ring (3) is installed in the support plate (4), the bellows (1) is placed on the support plate (4), the upper cover (2) is fastened to the support plate (4) by means of studs (6), and the upper cover (2) is sealed and connected to the bellows (1) by means of a first O-ring (9); The support plate (4) is installed in the base (5), and the base (5) is fastened to the upper cover (2) by bolts (11) and sealed by a second O-ring (10); The helium filling port at the top of the bellows (1) passes through the upper cover (2) and is connected to the helium cylinder, and the sampling inspection port at the bottom of the bellows (1) passes through the support plate (4) and the base (5) and is connected to the helium mass spectrometer leak detector.

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