Detection tool for helium leakage of box body flow channel welding seam in laboratory
By designing a detection tool and sealing structure with a closed detection space, the problems of low sensitivity, low efficiency and great safety hazards in helium leakage detection of box runner welds are solved, and efficient and accurate helium detection is achieved.
Patent Information
- Application Number
- CN202422177107.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-05
- Publication Date
- 2025-07-04
- Estimated Expiration
- 2034-09-05
AI Technical Summary
In the prior art, when detecting helium leakage in the box flow channel weld, there are problems such as low detection sensitivity, low efficiency, large safety hazards and excessive helium concentration.
A detection tool including a bracket, a working platform, an upper sealing plate and an isolation cover was designed. The detection space is closed through the isolation cover, combined with the exhaust device and a helium leak detector, and the sealing structure of high-purity helium is realized to prevent the diffusion of helium into the laboratory. The sealing structure of the locking tool and silicone pad plus steel plate is ensured to ensure high sensitivity and efficiency of detection.
It improves detection sensitivity and efficiency, avoids the impact of excessive helium concentration on detection, and ensures the accuracy and safety of detection.
Smart Images
Figure CN223064772U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of leakage detection, and specifically relates to a detection tool for helium leakage detection of the weld of the box body flow channel in a laboratory. Background Technique
[0002] For precision cooling workpieces such as civil and military aircraft cooling modules with box body flow channels, it is necessary to perform airtightness detection on the welds of the box body flow channels. Such box body flow channel workpieces 11 are as Figure 1 shown. The weld 12 of the box body flow channel workpiece 11 is located on the side of the workpiece 11, and wide openings are provided on both the front and back of the box body.
[0003] At present, the method for airtightness detection of the box body flow channel is the bubble method. The principle of the bubble method is: after sealing the upper and lower surfaces of the box body workpiece with a tooling, filling a certain pressure of nitrogen into the inner cavity of the box body, and then standing the box body workpiece in the liquid for a certain time to observe whether nitrogen bubbles of leakage are formed at the weld part of the flow channel. This method has the following disadvantages: First, the detection sensitivity is low, and the detected qualified products still show dripping phenomena during use. Second, there are certain safety hazards in the positive pressure method detection, and high requirements are imposed on the detection site. Third, the detection efficiency is low. For small leaks, it is mostly necessary to continuously observe for 1 - 2 hours to observe the generation of bubbles. Fourth, bubble detection cannot be quantified. The bubble method can only determine whether the product leaks, but cannot accurately measure the leakage rate of the leakage point.
[0004] The spray gun negative pressure method is different from the bubble method. The principle of the spray gun negative pressure method is: using a helium leak detector to evacuate the cavity of the workpiece box body. At the same time, spraying helium gas on the external weld area of the workpiece. If the workpiece has a leak, the helium gas enters the cavity of the workpiece box body from the leak point, and then enters the helium leak detector from the negative pressure cavity of the box body. The helium leak detector displays the leakage rate by detecting the helium gas. The spray gun negative pressure method can overcome the safety hazards and defects such as non - quantitative detection existing in the bubble method. However, the spray gun negative pressure method has the following difficulties in detecting such products:
[0005] First, it is difficult to seal such workpieces: Since wide openings are provided on both bottom surfaces of such workpieces, it is necessary to rely on suitable materials and tooling for sealing;
[0006] Second, high pressure during detection will cause the workpiece to deform. This workpiece is a precision part. When the inner cavity is evacuated, the sealing silica gel deforms with the change of pressure, resulting in the deformation of the workpiece and the internal rib plates.
[0007] Third, the detection efficiency is low during the laboratory spray gun method detection. Spraying helium gas on the outside of the workpiece will cause the helium gas concentration in the laboratory to be too high, thus greatly reducing the detection sensitivity and detection efficiency. Content of the Utility Model
[0008] The purpose of the present utility model is to provide a detection tooling for helium leakage detection of the weld seam of the inner box flow channel in a laboratory, so as to solve the problems of detection sensitivity and detection efficiency caused by too high helium concentration in the laboratory during the existing laboratory spray gun method detection.
[0009] The technical solution adopted by the present utility model is: a detection tooling for helium leakage of the weld seam of the inner box flow channel in a laboratory, including a bracket, a working platform and an upper sealing plate. An isolation cover which is transparent and has an operation door on the front side is installed on the bracket. The working platform is horizontally installed in the isolation cover. The upper sealing plate is freely arranged above the working platform, and a sealing tooling for sealing the workpiece is formed by the working platform and the upper sealing plate; a locking tooling for pressing the upper sealing plate downward along the vertical direction is arranged in the isolation cover; an exhaust device for discharging the excess helium gas in the isolation cover to the outside is arranged at the top of the isolation cover; a through hole is arranged in the middle of the working platform, and an exhaust pipe is used to connect the through hole with a helium leak detector.
[0010] Further, the upper sealing plate includes an upper silica gel pad and an upper steel plate, and the upper steel plate is vertically located above the upper silica gel pad; the working platform includes a lower silica gel pad and a lower steel plate, and the lower silica gel pad is vertically located above the lower steel plate.
[0011] Further, a handle is arranged on the upper steel plate.
[0012] Further, a connection joint is fixedly installed on the through hole, and the connection joint is hermetically connected with the through hole.
[0013] Further, the locking tooling includes a support cross beam and a screw rod arranged in the isolation cover. A threaded hole penetrating vertically is arranged in the middle of the support cross beam. The screw rod is threadedly connected to the threaded hole of the support cross beam. A rotating handle is arranged at the top end, and the bottom end is a pressing end for pressing the upper sealing plate.
[0014] Further, the pressing end of the screw rod is spherical.
[0015] Further, the exhaust device includes an exhaust pipe and a fan; the fan is installed at the top end of the isolation cover, one end of the exhaust pipe is connected to the fan, and the other end leads to the outside.
[0016] The beneficial effects of the present utility model are as follows: In the present utility model, a through-hole of a working platform is connected to a helium leak detector through an air extraction pipeline, and the negative pressure method of evacuating the inner cavity of a workpiece by the helium leak detector is adopted for detection, and the detection sensitivity is higher than that of the bubble method. The helium leak detector can quickly and intuitively read the leak point leak rate value, thereby providing a more detailed quality evaluation for the product. The detection space is enclosed by an isolation cover, so that the high-purity helium gas ejected by the spray gun will only diffuse in the detection space enclosed by the isolation cover, and will not spread to the entire laboratory. Then, in cooperation with an exhaust device, the redundant helium gas in the isolation cover is discharged, avoiding the problem of reduced detection sensitivity and detection efficiency caused by too high helium gas concentration in the detection space. The isolation cover is provided with an operation door, which is convenient for placing and taking the detected workpiece. The locking tooling presses the upper sealing plate vertically downward, which is beneficial to ensuring the relative effective sealing of the upper sealing plate and the working platform for the workpiece.
[0017] The front and back sides of the workpiece are sealed in the form of a silica gel pad plus a steel plate, which can ensure a good sealing effect and prevent the internal rib plate of the workpiece from being extruded and deformed by the compressed silica gel. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of a box body flow channel workpiece;
[0019] Figure 2 It is the front view of the detection tooling for helium leakage of the box body flow channel weld in the laboratory disclosed by the present utility model;
[0020] Figure 3 It is the left view of the detection tooling for helium leakage of the box body flow channel weld in the laboratory disclosed by the present utility model;
[0021] Figure 4 It is the top view of the detection tooling for helium leakage of the box body flow channel weld in the laboratory disclosed by the present utility model;
[0022] Figure 5 It is a schematic diagram of the sealing of the box body flow channel workpiece.
[0023] In the figure, there are support 1, working platform 2, lower silica gel pad 21, lower steel plate 22, upper sealing plate 3, upper silica gel pad 31, upper steel plate 32, handle 33, isolation cover 4, operation door, through-hole 5, connection joint 6, exhaust device 7, exhaust pipeline 71, fan 72, air extraction pipeline 8, locking tooling 9, support cross beam 91, screw 92, rotating handle 93, downward pressing end 94, helium leak detector 10, workpiece 11, weld 12. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0024] The following further describes the present utility model in conjunction with the drawings and embodiments:
[0025] The "upper", "lower", etc. indicating directions in the present utility model are all in their usage state positions, that is, in the attached Figure 1shall prevail, based on the appended Figure 1 The orientation or positional relationship shown is only for the convenience of describing the present utility model, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model.
[0026] A detection tool for helium leakage of the weld seam of the inner box body flow channel in the laboratory, as Figures 2 - 4 shown, includes a bracket 1, a working platform 2 and an upper sealing plate 3. An isolation cover 4 which is transparent and has an operation door on the front side is installed on the bracket 1. The working platform 2 is horizontally installed inside the isolation cover 4. The upper sealing plate 3 is freely arranged above the working platform 2, and a sealing tool for sealing the workpiece is formed by the working platform 2 and the upper sealing plate 3; a locking tool 9 for pressing the upper sealing plate 3 vertically downward is arranged inside the isolation cover 4; an exhaust device 7 for discharging the excess helium gas inside the isolation cover 4 to the outside is arranged at the top of the isolation cover 4; a through hole 5 is formed in the middle of the working platform 2, and a suction pipe 8 is used to connect the through hole 5 with a helium leak detector 10.
[0027] The detection tool for helium leakage of the weld seam of the inner box body flow channel in the laboratory disclosed by the present utility model, the bracket 1 serves to support components such as the working platform 2 and the isolation cover 4. The working platform 2 has two functions. Firstly, it supports the workpiece. Secondly, it serves as the lower sealing plate and, together with the upper sealing plate 3, seals the front and back sides of the workpiece, and the front and back sides are also the upper and lower sides. In this way, an inner cavity of the shell to be monitored is formed by enclosing the upper sealing plate 3 on the upper surface of the workpiece, the working platform 2 on the lower surface of the workpiece, and the peripheral side walls of the workpiece itself. The isolation cover 4 serves to enclose the detection space, that is, the workpiece is placed inside the isolation cover 4 for detection, so that the high-purity helium gas ejected by the spray gun will only diffuse in the detection space enclosed by the isolation cover 4 and will not spread to the entire laboratory. Together with the exhaust device 7, the excess helium gas inside the isolation cover 4 is discharged, avoiding the problem of reduced detection sensitivity and detection efficiency caused by too high helium gas concentration in the detection space. The isolation cover 4 is provided with an operation door for facilitating the placement and removal of the detection workpiece. The locking tool 9 presses the upper sealing plate 3 vertically downward, which is beneficial to ensuring the relative effective sealing of the workpiece between the upper sealing plate 3 and the working platform 2. The through hole 5 formed in the middle of the working platform 2 is used to connect the helium leak detector 10 through the suction pipe 8, so that the helium leak detector 10 can perform a vacuum detection on the inner cavity of the shell after sealing. The helium leak detector 10 evacuates the vacuum of the workpiece cavity and sprays helium gas on the external weld area of the workpiece. If the workpiece has a leak, the helium gas enters the negative pressure cavity from the leak point and then enters the helium leak detector, and the leakage rate is displayed. It should be noted that the spray head for spraying helium gas on the external weld of the workpiece and other settings not shown in this embodiment are arranged inside the isolation cover 4.
[0028] When the negative pressure is pumped in the inner cavity of the workpiece, the sealing silica gel such as the internal rib plate is deformed with the change of pressure, which easily leads to the deformation of the workpiece and the internal rib plate. In order to ensure the sealing performance and prevent the internal rib plate of the workpiece from being extruded and deformed by the compressed silica gel. Preferably, as Figure 5 shown, the upper sealing plate 3 includes an upper silica gel pad 31 and an upper steel plate 32. The upper steel plate 32 is vertically located above the upper silica gel pad 31; the working platform 2 includes a lower silica gel pad 21 and a lower steel plate 22. The lower silica gel pad 21 is vertically located above the lower steel plate 22. The process parameters of the upper steel plate 32 and the lower steel plate 22 are very important for sealing. In order to distinguish good sealing effects, the roughness requirements of the upper steel plate 32 and the lower steel plate 22 are ≤6.3μm, and the flatness is 0.05mm. The thickness of the upper silica gel pad 31 is 10mm, and the thickness of the upper steel plate 32 is 20mm; the thickness of the lower silica gel pad 21 is 5mm, and the thickness of the lower steel plate 22 is 20mm. The 10mm upper silica gel pad 31 and the 5mm lower silica gel pad 21 are ideal thicknesses, which can ensure good sealing effects and prevent the internal rib plate of the workpiece from being extruded and deformed by the compressed silica gel. The circular through hole 5 penetrating the lower silica gel pad 21 can prevent the workpiece deformation caused by the deformation of the silica gel pad.
[0029] In order to facilitate placing the upper sealing plate 3 on the workpiece or removing it from the workpiece, preferably, a handle 33 is provided on the upper steel plate 32.
[0030] Preferably, a connection joint 6 is fixedly installed on the through hole 5, and the connection joint 6 is hermetically connected to the through hole 5. The air extraction pipeline 8 usually adopts a corrugated pipe. One end of the air extraction pipeline 8 is connected to the connection joint 6 from below the working platform 2, and the other end is connected to the helium leak detector 10. The air extraction pipeline 8 is connected from below the working platform 2. Each time when detecting, only the workpiece needs to be placed in a fixed area for detection, without disassembling the connection joint 6 each time, and without moving the sealing position back and forth. It can improve the calibration efficiency to a greater extent.
[0031] The locking tooling 9 can adopt a hydraulic cylinder, etc. In this embodiment, the locking tooling 9 includes a support cross beam 91 and a screw rod 92 arranged in the isolation cover 4. A vertically penetrating threaded hole is provided in the middle of the support cross beam 91. The screw rod 92 is threadedly connected to the threaded hole of the support cross beam 91. A rotating handle 93 is provided at its top end, and a pressing end 94 for pressing down the upper sealing plate 3 is provided at its bottom end. When in use, after the workpiece is placed flat on the working platform 2, the upper sealing plate 3 is covered, and the rotating handle 93 is rotated to lower the screw rod, so as to clamp the workpiece to make it sealed. The rotating handle 93 can adopt a rotating wheel. The rotating wheel type rotating locking method is labor-saving and convenient to operate in a limited space.
[0032] The pressing end 94 of the screw 92 can be planar. In this embodiment, the pressing end 94 of the screw 92 is spherical. The spherical point contact is selected to replace the cylindrical surface contact, which reduces the friction between the upper steel plate 32 and the pressing end 94 of the screw 92, and avoids the problem of seal failure caused by the displacement of the upper steel plate 32 due to the rotation of the screw.
[0033] Preferably, the exhaust device 7 includes an exhaust pipe 71 and a fan 72; the fan 72 is installed at the top of the isolation hood 4, one end of the exhaust pipe 71 is connected to the fan 72, and the other end leads to the outside. The exhaust device 7 is equipped with a switch for opening and closing the fan 72. During detection, the fan 72 is briefly closed. After detection, the operation door of the isolation hood is closed. After a certain time of ventilation, the next detection is carried out to avoid too much helium in the isolation hood being sucked into the helium leak detector during the detection vacuuming, improving the detection background and reducing the detection sensitivity. Try to avoid helium leaking into the laboratory.
[0034] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A detection tool for helium leakage of the weld seam of the inner box flow channel in the laboratory, characterized in that: It includes a bracket (1), a working platform (2) and an upper sealing plate (3). An isolation cover (4) which is transparent and has an operation door on the front side is installed on the bracket (1). The working platform (2) is horizontally installed inside the isolation cover (4). The upper sealing plate (3) is freely arranged above the working platform (2). A sealing tooling for sealing workpieces is constituted by the working platform (2) and the upper sealing plate (3). A locking tooling (9) for pressing the upper sealing plate (3) downward vertically is arranged inside the isolation cover (4). An exhaust device (7) for discharging the redundant helium gas inside the isolation cover (4) to the outside is arranged at the top of the isolation cover (4). A through hole (5) is provided in the middle of the working platform (2), and an air extraction pipe (8) is used to connect the through hole (5) and a helium leak detector (10).
2. The detection tool for helium leakage of the weld seam of the inner box flow channel in the laboratory according to claim 1, characterized in that: The upper sealing plate (3) includes an upper silica gel pad (31) and an upper steel plate (32), and the upper steel plate (32) is vertically located above the upper silica gel pad (31). The working platform (2) includes a lower silica gel pad (21) and a lower steel plate (22), and the lower silica gel pad (21) is vertically located above the lower steel plate (22).
3. The detection tool for helium leakage of the weld seam of the inner box flow channel in the laboratory according to claim 2, characterized in that: A handle (33) is arranged on the upper steel plate (32).
4. The detection tool for helium leakage of the weld seam of the inner box flow channel in the laboratory according to claim 1, characterized in that: A connection joint (6) is fixedly installed on the through hole (5), and the connection joint (6) is hermetically connected to the through hole (5).
5. The detection tooling for helium leakage of the weld seam of the inner box flow channel in the laboratory according to any one of claims 1-4, characterized in that: The locking tooling (9) includes a support cross beam (91) and a screw rod (92) arranged inside the isolation cover (4). A vertically through threaded hole is provided in the middle of the support cross beam (91). The screw rod (92) is threadedly connected to the threaded hole of the support cross beam (91). A rotary handle (93) is arranged at its top end, and a downward pressing end head (94) for pressing the upper sealing plate (3) downward is arranged at the bottom end.
6. The detection tooling for helium leakage of the weld seam of the inner box flow channel in the laboratory as described in claim 5, characterized in that: The downward pressing end head (94) of the screw rod (92) is spherical.
7. The detection tooling for helium leakage of the weld seam of the inner box flow channel in the laboratory according to any one of claims 1-4, characterized in that: The exhaust device (7) includes an exhaust pipe (71) and a fan (72). The fan (72) is installed at the top of the isolation cover (4). One end of the exhaust pipe (71) is connected to the fan (72), and the other end leads to the outside.