Vacuum helium mass spectrum leak detection method and device for corrugated pipe products

Abstract

The invention provides a vacuum helium mass spectrum leak detection method and device for corrugated pipe products. The vacuum helium mass spectrum leak detection method comprises the following steps that S1, corrugated pipes are fixed through supporting rings; s2, the supporting ring and the supporting plate are assembled; s3, a first O-shaped ring is placed between the corrugated pipe and the upper cover for sealing, and the upper cover, the corrugated pipe and the supporting plate are fixed through studs; s4, the fixed corrugated pipe is placed on a base, a second O-shaped ring is placed between the base and an upper cover for sealing, and bolts are adopted for fixing; s5, the assembled corrugated pipe is vertically placed, a helium mass spectrometer leak detector is connected with a sampling inspection opening in the bottom, and the outside of the corrugated pipe is vacuumized; and S6, connecting the helium tank connected with the pressure reducing valve with a top helium filling port, and filling helium into the corrugated pipe for leak rate inspection. According to the invention, the corrugated pipe is ensured not to be stretched under the stamping condition and not to be distorted and deformed; the effectiveness of sealing between the corrugated pipe and the upper cover is ensured; the detection result is accurate and reliable.

Description

Technical Field

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

[0002] Bellows products are key structural parts in the booster delivery system of launch vehicles, and are usually welded together by dozens of diaphragms, upper covers, and bases. Helium mass spectrometry leak rate is an important performance indicator of bellows. Since bellows are elastic structural parts, it is difficult to effectively seal them. In addition, they are prone to distortion, stretching, and other problems under pressure, which damages product quality. Therefore, it is very difficult to perform vacuum helium mass spectrometry leak rate inspections on bellows products.

[0003] The existing Chinese patent with publication number CN212030845U discloses a helium mass spectrometer leak detection device for a bellows assembly, which includes a bellows assembly to be detected, 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 at 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 inner support block of the bellows, the connecting screws of the upper sealing flange are connected to the inner support block of the bellows, 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 arranged in an annular groove on the lower flange through a lower O-ring.

[0004] At present, in the production of bellows products, helium mass spectrometer leak rate inspection is generally not carried out in the bellows state, but the inspection is carried out in the assembly state after the bellows shell is welded. In the above method, once the bellows leak rate exceeds the standard, the entire assembly will be scrapped, which is a great waste of production cost, 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 object 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: Step S1, fixing the bellows with a support ring; Step S2, assembling the support ring and the 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 the 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, 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.

[0008] 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.

[0009] Preferably, in step S1, the support ring comprises two semicircular support rings, and the semicircular support rings are obtained by linear cutting along a diameter line after integral turning, and the cutting line width is ≤0.5 mm.

[0010] Preferably, in step S1, 8-10 ventilation grooves are evenly 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.

[0011] 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.

[0012] Preferably, in step S2, the bottom end of the bellows is placed on a support plate, and the support plate is provided with 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.

[0013] 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.

[0014] Preferably, in step S3, the stud is arranged on the outside of the support ring, the top end of the stud is first screwed and then welded to the upper cover, 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.

[0015] 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 with the upper surface of the base, a sealing groove for installing 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; 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.

[0016] A vacuum helium mass spectrometer leak detection device for bellows products provided by the present invention is applied to the vacuum helium mass spectrometer leak detection method for bellows products, comprising: an upper cover, a support ring, a support plate, and a base; 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 and installed on the support plate by studs, and the upper cover is sealed and connected to the bellows by a first O-ring; 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; 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.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The invention ensures the height of the bellows by adopting a support ring and a support plate, and ensures that the bellows will not be stretched and twisted and deformed under stamping conditions; the bellows and the upper cover are sealed by adopting multiple O-rings, studs, support rings and support plates, and the effectiveness of the seal between the bellows and the upper cover during the sealing process of the upper cover and the base is ensured; the studs and the upper cover are first screwed and then welded, so as to effectively prevent welding deformation and ensure assembly accuracy; the helium filling port is exposed to the air, so that the problem of excessive leakage rate caused by poor sealing of the filling port is easily eliminated; the vacuum cover positive pressure helium mass spectrometry leak detection of bellows products is realized, and the detection result is accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 This is a schematic diagram of the structure of a vacuum helium mass spectrometer leak detection device for bellows products, which is mainly embodied in the present invention; Figure 2 It is a schematic diagram mainly showing the connection between the bellows and the support ring of the present invention.

[0019] 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

[0020] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments 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 of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0021] Example 1 like Figure 1 As shown, a vacuum helium mass spectrometry leak detection method for bellows products provided by the present invention comprises the following steps: Step S1, fixing the bellows 1 with a support ring 3; Step S2, assembling the support ring 3 and 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 using studs 6; Step S4, placing the fixed bellows 1 on the base 5, placing a second O-ring 10 for sealing between the base 5 and the upper cover 2, and fixing them with bolts 11; 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.

[0022] The vacuum helium mass spectrometry leak detection method for bellows products of the present application can effectively solve the problems that vacuum cover inspection of bellows products is difficult to achieve and bellows are prone to twisting and stretching deformation during the leak detection process, and the detection results are accurate and reliable.

[0023] like Figure 2As shown, in step S1, the height of the support ring 3 matches the height of the bellows 1, that is, except for the part of the support ring 3 inserted into the support plate 4, the height of the remaining part 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, and 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 part between the support ring 3 and the bellows 1 should be consistent, and the sharp edges are rounded, the surface roughness is not less than the surface roughness of the bellows 1, and 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.

[0024] In step S1, the support ring 3 includes two semicircular support rings, which are obtained by integral turning and then line cutting along the diameter line, and the cutting line width is ≤0.5 mm. Preferably, the cutting line width is 0.3 mm.

[0025] In step S1, 8-10 ventilation grooves are evenly distributed along the circumferential direction on 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.

[0026] In step S2, the support ring 3 and the support plate 4 are assembled, and the bottom end of the support ring 3 is inserted into the slot on the upper surface of the support plate 4. The matching tolerance between the outer diameter of the support ring 3 and the outer diameter of the slot should be controlled within 0-0.10mm.

[0027] In step S2, the bottom end of the bellows 1 is placed on the support plate 4, and 6-8 ventilation grooves are evenly distributed along the circumferential direction at the contact part between the support plate 4 and the bellows 1, and the width of the ventilation grooves is 2-4 times the radial width of the contact part 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 part between the support plate 4 and the bellows 1.

[0028] In step S3, a first O-ring 9 is placed between the bellows 1 and the upper cover 2 for sealing. A sealing groove for installing the 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. 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 should be 30% of the wire diameter.

[0029] 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 by a first washer 7 and a first nut 8.

[0030] In step S4, the fixed bellows 1 is placed on the base 5, and the 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 fitted with the upper surface of the base 5. The upper cover 2 is provided with a sealing groove for installing 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 with the height of the sealing groove should be 30% of the wire diameter.

[0031] In step S4 , the bolt 11 is disposed on the outside of the second O-ring 10 , and the bolt 11 passes through the upper cover 2 and the base 5 and is fixed by the second washer 12 and the second nut 13 .

[0032] 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 is 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.

[0033] Example 2 Based on Example 1, a vacuum helium mass spectrometer leak detection device for a bellows product provided in accordance with the present invention comprises: 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 means of studs 6, and the upper cover 2 is sealed to the bellows 1 by means of 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 means of bolts 11 and is sealed by means of a second O-ring 10; the helium filling port at the top of the bellows 1 is connected to the helium cylinder through the upper cover 2, and the sampling port at the bottom of the bellows 1 is connected to the helium mass spectrometer leak detector through the support plate 4 and the base 5.

[0034] By adopting 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, while 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.

[0035] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0036] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

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); Step S2, assembling the support ring (3) and the support plate (4); Step S3, placing a first O-ring (9) between the bellows (1) and the upper cover (2) for sealing, and fixing the upper cover (2), the bellows (1) and the support plate (4) with studs (6); 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 them with bolts (11); 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 the step S1, the height of the support ring (3) matches the height of the bellows (1), the top end 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), the sharp edges are rounded, the surface roughness is not less than the surface roughness of the bellows (1), and the length of the support portion extending into the bellows (1) is within 30%-50% of the width of the corrugation.

3. The vacuum helium mass spectrometry leak detection method for bellows products according to claim 1, characterized in that: In the step S1, the support ring (3) comprises two semicircular support rings, which are obtained by linear cutting along a diameter line after integral turning, and the cutting line width is ≤0.5 mm.

4. The vacuum helium mass spectrometry leak detection method for bellows products according to claim 1, characterized in that: In the step S1, 8 to 10 ventilation grooves are evenly distributed along the circumferential direction on the side wall of the support ring (3), and the height of the ventilation grooves is within 40% to 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 the step S2, the bottom end of the support ring (3) is inserted into a slot on the upper surface of the support plate (4), and the matching 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 bottom end of the bellows (1) is placed on a support plate (4), and the support plate (4) is provided with 6 to 8 ventilation grooves evenly distributed along the circumference, wherein the width of the ventilation grooves is 2 to 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 mounting 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 as claimed in claim 1, characterized in that: In step S3, 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).

9. The vacuum helium mass spectrometry leak detection method for bellows products as claimed in claim 1, characterized in that: In the step S4, the wire diameter of the second O-ring (10) is greater than the wire diameter of the first O-ring (9), the lower surface of the upper cover (2) is arranged in contact with the upper surface of the base (5), and a sealing groove for mounting the second O-ring (10) is provided on the upper cover (2), 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; The bolt (11) is arranged on the outside of the second O-ring (10), and the bolt (11) passes through the upper cover (2) and the base (5) and is fixed by the second washer (12) and the second nut (13).

10. A vacuum helium mass spectrometer leak detection device for bellows products, applied to the vacuum helium mass spectrometer leak detection method for bellows products according to any one of claims 1 to 9, 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 sealingly 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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