Air tightness confirmation device

Abstract

To provide an air tightness confirmation device capable of more accurately recognizing a position of a poor weld when there is a poor weld area even with a simple configuration.SOLUTION: An air tightness confirmation device arranged on an inspection surface for a wilding part, includes: a box body defining an internal space together with the inspection surface and having an opening opening the internal space; and a packing sealing between the box body and the inspection surface. The box body includes: a peripheral part defining the opening; a transparent window arranged in a part different from the peripheral part and capable of visually recognizing the inspection surface from an outside; a vacuum drawing port communicating with the internal space and connected to a vacuum drawing device; and a liquid feeding port communicating with the internal space and allowing a liquid to flow thereinto. The packing is located in the peripheral part or on an outer peripheral side of the peripheral part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an airtightness checking device used to inspect whether airtightness of a welded joint is maintained. [Background technology]

[0002] Patent Document 1 discloses a vacuum chamber forming device for weld leakage inspection, which is used to inspect whether there is a portion of a welded portion that is not airtight. In the vacuum chamber forming device for weld leakage inspection of Patent Document 1, soapy water is applied to the welded portion in advance, and a vacuum chamber is formed surrounding the welded portion by a packing and a plate-shaped packing fixing portion on top of the soapy water, and the vacuum chamber is evacuated there. When there is an airtight defect in the welded portion, air enters the vacuum chamber due to the pressure difference with the outside caused by negative pressure. At that time, the air passes through the portion where the soapy water is applied, so bubbles are generated at the position where there is an airtight defect. By checking whether there is a bubble, it is possible to inspect whether there is an airtight defect. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-141755 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, the soapy water needs to be applied, and when there is a part with poor airtightness, bubbles only come out from there one-off, so there is a possibility that the inspector will miss the bubbles when they immediately break. Also, since there is a limit to the amount of soapy water that can be applied, if the bubbles break or blow away, there will be a shortage of soapy water at that point, and bubbles will not continue to be generated there even if there is a poor airtightness. Therefore, even if an inspection is performed using the vacuum chamber forming device for weld leakage inspection disclosed in Patent Document 1, it is difficult to detect the position where the poor airtightness has occurred.

[0005] Therefore, an object of one embodiment of the present disclosure is to provide an airtightness checking device that has a simple configuration and is capable of more accurately identifying the location of a portion of poor airtightness in a welded portion when such a portion is present. [Means for solving the problem]

[0006] An airtightness confirmation device according to one embodiment of the present disclosure is an airtightness confirmation device for a welded portion that is placed on an inspection surface, and comprises a box body that defines an internal space together with the inspection surface and has an opening that opens the internal space, and a gasket that seals between the box body and the inspection surface, wherein the box body has a peripheral portion that defines the opening, a transparent window that is located in a part different from the peripheral portion and allows the inspection surface to be viewed from the outside, a vacuum port that communicates with the internal space and is connected to a vacuum device, and a liquid supply port that communicates with the internal space and allows liquid to flow in, and the gasket is located at the peripheral portion or on the outer circumferential side of the peripheral portion. Effect of the Invention

[0007] According to one aspect of the present disclosure, when the airtightness of the weld is not maintained, air bubbles are continuously generated inside the liquid from the inspection surface, making it possible to more accurately identify the location of the portion of the weld where the airtightness is not maintained. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view of an airtightness confirmation device according to an embodiment; [Diagram 2] 2 is a cross-sectional view of the airtightness checking device of FIG. 1 during inspection. FIG. [Diagram 3] 2 is an enlarged perspective view showing the periphery of a support part in the airtightness checking device of FIG. 1. [Figure 4] FIG. 2 is a perspective view of the airtightness checking device of FIG. 1 during inspection. [Diagram 5] FIG. 11 is a perspective view of an airtightness confirmation device according to another embodiment. [Figure 6] FIG. 11 is a side view of an airtightness confirmation device according to still another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An airtightness confirmation device according to an embodiment will be described below with reference to the accompanying drawings. Fig. 1 shows a perspective view of an airtightness confirmation device 1 according to an embodiment. Fig. 2 shows a cross-sectional view of the airtightness confirmation device 1 according to an embodiment, taken along a plane extending in the up-down and front-rear directions at approximately the center position in the width direction D1. Hereinafter, the width direction of the airtightness confirmation device 1 is referred to as D1, and the direction perpendicular to the width direction D1 in the horizontal plane is referred to as the front-rear direction D2.

[0010] The airtightness confirmation device 1 is a device for confirming airtightness of welded parts, used when inspecting whether or not airtightness is maintained for welded parts of a workpiece that have been welded. The airtightness confirmation device 1 includes a box body 2. When an inspection is performed to confirm airtightness of the welded part P, the box body 2 is placed on the welded workpiece W so as to cover from above the inspection surface S of the welded workpiece W on which the inspection is performed. Therefore, during inspection, the inspection surface S of the welded part P of the welded workpiece W is surrounded by the box body 2. Here, the inspection surface S refers to the portion of the welded part P that is covered by the box body 2.

[0011] In this embodiment, the box body 2 is formed from resin using a 3D printer. Since the box body 2 is formed using a 3D printer, the shape of each box body 2 can be manufactured to match the area where inspection is performed to check the airtightness of each welded part. This makes it possible to easily manufacture box bodies 2 in shapes that match the areas where airtightness check is performed. Box bodies 2 formed by means other than a 3D printer are also included.

[0012] The box body 2 is configured to define an internal space 3 on the inside. The box body 2 has an opening 4 that opens the internal space 3 to the outside. The box body 2 is configured to have a concave shape that is recessed inward from the opening 4. The opening 4 is defined by a peripheral portion 5 of the box body 2. A packing 6 is provided on the peripheral portion 5 of the box body 2. The packing 6 is attached to the box body 2 to seal between the box body 2 and the inspection surface S. This makes it possible to prevent the liquid stored in the internal space 3 from leaking out from the opening 4 of the box body 2 to the outside. The packing 6 is formed of a flexible material to seal between the box body 2 and the inspection surface S. In this embodiment, for example, the packing 6 is formed of a sponge tape having a tape surface for adhesion formed on a sponge body. In this embodiment, the packing 6 is configured to be provided on the peripheral portion 5 of the opening 4 in the box body 2, but the packing 6 may be located on the outer periphery side of the peripheral portion 5 of the opening 4. In other words, the packing 6 needs to be disposed at a position where it can prevent liquid from leaking from the internal space 3.

[0013] In this embodiment, the box 2 has a box body 2a and a transparent window 2b separate from the box body 2a. The box body 2a has a hole 2c that opens the internal space 3 and a peripheral portion 2d that defines the hole 2c. The transparent window 2b is fitted from the outside of the peripheral portion 2d and then sealed all around. As a result, the transparent window 2b is attached to the box body 2a so as to close the hole 2c. The transparent window 2b is made of a transparent material so as to make the internal space 3 visible from the outside. In this embodiment, the transparent window 2b is formed in a plate shape. In this embodiment, for example, the transparent window 2b is formed of a plate-shaped transparent resin, for example, polycarbonate.

[0014] In this embodiment, the transparent window 2b is provided at a position facing the inspection surface. Therefore, in this embodiment, the transparent window 2b is located above the inspection surface in the box 2. In other words, the transparent window 2b is arranged so as to face the opening 4. As a result, in this embodiment, the transparent window 2b is arranged in a portion different from the peripheral portion 5 of the opening 4.

[0015] The box 2 has a protruding portion 8 that protrudes upward from the position where the transparent window 2b is provided and is provided on one side in the front-rear direction D2. The protruding portion 8 forms an air bubble reservoir 9. The air bubble reservoir 9 is defined as part of the internal space 3 by the protruding portion 8 of the box 2. Therefore, the air bubble reservoir 9 is provided at a position protruding vertically upward inside the internal space 3. The protruding portion 8 is provided with a vacuum port 10 that communicates with the air bubble reservoir 9 of the internal space 3 and is connected to a vacuum device.

[0016] The vacuum port 10 is connected to a vacuum device, such as a vacuum pump, via an air supply pipe 11 capable of circulating air. Therefore, by operating the vacuum device, air can be forcibly discharged from the bubble reservoir 9. This makes it possible to reduce the pressure in the internal space 3. In addition, the pressure inside the internal space 3 can be adjusted by adjusting the amount of air discharged from the vacuum device. In this example, a vacuum ejector is used as the vacuum device.

[0017] In this embodiment, the vacuum port 10 is provided at the top of the protruding portion 8 of the box body 2, and is arranged on the vertically upward side of the box body 2. Particularly in this embodiment, the vacuum port 10 is provided in the box body 2 so as to communicate with the highest position of the internal space 3.

[0018] In this embodiment, the transparent window 2b is provided in the box 2 so as to be inclined upward toward one side in the front-rear direction D2. That is, the transparent window 2b is inclined so as to be vertically upward toward the air bubble reservoir 9. In this embodiment, as shown in Fig. 2, the transparent window 2b occupies substantially the entire area between the end 15 on the other side of the box 2 in the front-rear direction D2 and the end 8a of the protruding portion 8 on the other side in the front-rear direction D2 in the front-rear direction D2 of the box 2.

[0019] The box 2 has a liquid supply port 12 communicating with the internal space 3. The liquid supply port 12 is connected to a liquid supply pipe 13 capable of circulating liquid inside. The liquid supply pipe 13 is connected to, for example, a tank in which liquid is stored. In addition, the liquid supply pipe 13 is provided with a flow rate control valve 14 capable of adjusting the flow rate of the liquid inside the liquid supply pipe 13. In this embodiment, water is used as the liquid stored in the internal space 3. In this example, the liquid supply port 12 is provided near the opening 4 of the box body main body 2a at a position that does not overlap with the vacuum port 10 in a top view.

[0020] The box body 2a has a support portion 2f that receives the transparent window 2b at an adjacent side 2e adjacent to the air bubble reservoir 9 in the peripheral portion 2d of the hole 2c. FIG. 3 shows an enlarged perspective view of the periphery of the support portion 2f. In this embodiment, the support portion 2f partially protrudes toward the hole 2c from a part of the adjacent side 2e adjacent to the air bubble reservoir 9 in the peripheral portion 2d of the hole 2c. That is, in this embodiment, the support portion 2f is not provided over the entire width direction D1 of the adjacent side 2e, but is provided only in a part of the width direction D1. In this embodiment, the support portion 2f is provided only in a part near the center of the width direction D1 of the adjacent side 2e.

[0021] The box body main body 2a of the box body 2 has a protrusion 16 protruding from an inner periphery 5a of the peripheral portion 5 of the opening 4 of the box body 2 in a direction in which the packing 6 is pressed against the inspection surface S. Since the protrusion 16 is provided from the inner periphery 5a of the peripheral portion 5 toward the inspection surface S, the protrusion 16 is located on the inside in the horizontal direction of the packing 6. In other words, the protrusion 16 is provided on the peripheral portion 5 of the box body 2 on the inside of the packing 6 in the width direction D1 and the front-rear direction D2.

[0022] The airtightness checking device 1 configured as described above is used to check whether the airtightness of the welded part P of the welded work W is maintained. FIG. 4 shows a perspective view of a state in which the airtightness checking device 1 is used to check whether the airtightness of the welded part P is maintained. During the inspection, the internal space 3 is evacuated through the vacuum port 10 with the packing 6 placed on the inspection surface S of the welded work W so as to surround the inspection surface S of the welded part P. Then, when it is confirmed that the air is discharged from the internal space 3 and the pressure inside the internal space 3 becomes vacuum or low pressure, and the packing 6 is in close contact with the inspection surface 6, the flow rate control valve 14 is opened to supply liquid to the internal space 3 through the liquid supply port 12. This allows liquid to be stored in the vacuum or low pressure internal space 3 of the box body 2.

[0023] When the box body 2 is applied to the inspection surface S of the welded portion P of the welded work W via the packing 6 and liquid is stored in the internal space 3, if the airtightness of the welded portion P is not maintained, air will flow into the internal space 3 through the welded portion P due to the pressure difference between the internal space 3 and the outside. Therefore, the air present on the back side of the welded portion P will enter the internal space 3 through the welded portion P. Since liquid is stored in the internal space 3, the air that has entered the internal space 3 becomes air bubbles B and is visualized to the inspector. Therefore, the inspector can identify the part of the welded portion P where airtightness is not maintained by visually checking the air bubbles B. On the other hand, when the airtightness of the welded portion P is maintained, the welded portion P does not allow air to pass through. Therefore, even if the box body 2 is applied to the inspection surface S of the welded portion P of the welded work W in a state where liquid is stored in the vacuum or low-pressure internal space 3, air bubbles B will not be generated and it can be determined that airtightness is maintained. Therefore, by checking the presence or absence of air bubbles and their location, an inspector can determine whether the weld P is airtight or not, and identify the areas where airtightness is not maintained.

[0024] According to the above embodiment, when the welded portion P of the inspection surface S has a welding defect and is not airtight, bubbles B generated from the welded portion P are continuously generated in the liquid. The inspector can visually check the state of the internal space 3 through the transparent window 2b and check the presence or absence of bubbles B to inspect whether the airtightness of the welded portion P is maintained. Furthermore, when bubbles B are generated, the position where the bubbles B are generated can be confirmed to identify the position where the welded portion is not airtight due to a welding defect. At this time, bubbles B are continuously generated in the liquid, so the inspector can recognize the bubbles B without overlooking their presence.

[0025] Furthermore, according to the above embodiment, the vacuum port 10 is provided on the protruding portion 8 of the box 2 and is disposed on the vertically upward side of the box 2, which makes it possible to prevent liquid from entering the vacuum port 10. Therefore, it is possible to prevent liquid from interfering with the discharge of air from the vacuum port 10 during evacuation.

[0026] Furthermore, according to the above embodiment, the transparent window 2b is disposed above the inspection surface S so as to face the opening 4 of the box body 2, and therefore the position where the bubbles B are generated can be easily visually confirmed through the transparent window 2b. Therefore, when there is a defect in airtightness in the welded portion P of the inspection surface S, the position where the bubbles B are continuously generated inside the liquid can be visually confirmed, and the position where the welding defect occurs can be accurately recognized.

[0027] Furthermore, according to the above embodiment, since the air bubble reservoir 9 is provided at a position on the vertically upward side of the box 2 so as to protrude vertically upward, the air bubble reservoir 9 can be disposed at a position vertically above the transparent window 2b. Therefore, the liquid can be stored in the internal space 3 of the box 2 until it comes into contact with the transparent window 2b. In this embodiment, the liquid is stored in the internal space 3 such that when the liquid is stored inside the internal space 3, the liquid comes into contact with the transparent window 2b over the entire vertical direction of the transparent window 2b. This makes it possible to prevent the transparent window 2b from becoming cloudy or the visibility from being reduced due to the adhesion of water droplets when the liquid is stored in the internal space 3.

[0028] Furthermore, according to the above embodiment, the transparent window 2b is inclined vertically upward as it approaches the air bubble reservoir 9, so that air bubbles B generated when there is poor airtightness at the welded part P rise from the inspection surface S inside the liquid, reach the transparent window 2b, and are then guided along the transparent window 2b to the air bubble reservoir 9. This makes it possible to prevent the air bubbles B from accumulating at the position of the transparent plate part. This makes it possible to prevent the air bubbles B that are generated at the position of poor airtightness and rise from there from remaining at a position inside the transparent window 2b, and makes it possible to prevent the air bubbles B remaining in the transparent window 2b from reducing visibility to the inspector.

[0029] According to the above embodiment, the box body main body 2a has the support portion 2f that receives the transparent window 2b at the adjacent side 2e of the peripheral portion 2d of the hole 2c that is adjacent to the air bubble reservoir 9, so that the transparent window 2b is supported by the support portion 2f, and the transparent window 2b can be more reliably fixed to the box body main body 2a. The support portion 2f only partially protrudes from a part of the adjacent side 2e of the peripheral portion 2d of the hole 2c toward the hole 2c, and does not protrude toward the hole 2c over the entire adjacent side 2e. In this embodiment, as shown in FIG. 3, the support portion 2f only protrudes toward the hole 2c in the region A1 near the center in the width direction D1 of the box body main body 2a, so there is a region A2 where the support portion 2f does not protrude from the adjacent side 2e. Therefore, when the air bubble B rises along the transparent window 2b toward the air bubble reservoir 9, the air bubble B can be released toward the air bubble reservoir 9 in the region A2 on the adjacent side 2e where the support portion 2f does not protrude. For example, as shown by arrows D3 and D4 in Fig. 3, air bubbles B generated at a position where there is poor airtightness can avoid the support portion 2f, pass through the area A2 where the support portion 2f does not protrude, and move toward the air bubble reservoir 9. Therefore, it is possible to prevent the air bubbles B generated at a position where there is poor airtightness from accumulating at the position of the support portion 2f during the process of the air bubbles B rising inside the liquid to reach the transparent window 2b and then moving along the transparent window 2b to the air bubble reservoir 9. This makes it possible to prevent the air bubbles B accumulated around the support portion 2f from reducing the visibility of the transparent window 2b to the examiner.

[0030] Furthermore, according to the above embodiment, the box body 2a of the box 2 has the protrusion 16 protruding from the inner periphery 5a of the periphery 5 of the opening 4, so that the packing 6 is prevented from being pulled toward the internal space 3 by the negative pressure in the internal space 3, and the position of the packing 6 is prevented from being shifted. Therefore, the packing 6 is more reliably present between the box 2 and the inspection surface S, and the packing 6 can prevent liquid from leaking from between the inspection surface S and the box 2. This makes it possible to maintain a low pressure state in the internal space 3.

[0031] In the above embodiment, the inspection surface S of the welded portion P is a surface extending substantially straight along the width direction D1 and the front-rear direction D2, and accordingly, the peripheral portion 5 of the opening 4 of the box body 2 and the packing 6 extend straight along the width direction D1 and the front-rear direction D2, but this is not limited to the above embodiment. If the inspection surface S has an uneven shape, the peripheral portion 5 of the box body 2 may have an uneven shape that matches the uneven shape of the inspection surface S.

[0032] FIG. 5 shows a perspective view of the airtightness confirmation device 1A and the inspection surface S when the inspection surface S has an uneven shape. As shown in FIG. 5, at the welded portion P, the plate material having the unevenness and the flat plate are joined by fillet welding. Therefore, the plate material has an uneven shape, and the inspection surface S has an uneven shape at the position where the fillet welding is performed. In this embodiment, the airtightness confirmation device 1A is configured so that the peripheral portion 5 of the opening 4 in the airtightness confirmation device 1A has an uneven shape in accordance with the uneven shape of the plate material, and the peripheral portion 5 of the opening 4 in the airtightness confirmation device 1A has an uneven shape in accordance with the uneven shape of the inspection surface S. In this embodiment, a part of the end surface 17 in the front-rear direction D2 of the box body 2 has an uneven shape so as to be recessed upward in the up-down direction. In this embodiment, the airtightness confirmation device 1A is configured so that the end surface 17 in the front-rear direction D2 of the box body 2 has a recess 18 recessed upward at approximately the center of the width direction D1 of the box body 2. In this embodiment, the recesses 18 of the end face 17 are tapered upward toward the inside at both ends in the width direction D1. In accordance with the recesses 18 on the end face 17 in the front-rear direction D2 of the box body 2, the packing 6 is disposed so as to be recessed upward along the recesses 18. The airtightness checking device 1A is configured so that the end face 17 in the front-rear direction D2 of the box body 2 has a step portion 21 in accordance with the recesses formed by fillet welding, in addition to the recesses formed in accordance with the uneven shape of the plate material.

[0033] Since the peripheral portion 5 of the box body 2 has an uneven shape that matches the uneven shape of the step portion 21 of the inspection surface S of the welded portion P in the welded work W, even if the inspection surface S has unevenness, the box body 2 can be made to conform to the uneven shape of the inspection surface S. In addition, since the peripheral portion 5 of the box body 2 has an uneven shape that matches the uneven shape of the plate material, even if the plate material has unevenness, the box body 2 can be made to conform to the uneven shape of the plate material. Therefore, it is possible to prevent liquid from leaking from the gap between the box body 2 and the inspection surface S. Therefore, the state in which the liquid is stored in the internal space 3 of the box body 2 is maintained simply by applying the box body 2 to the inspection surface S via the packing 6, and it is possible to inspect whether the airtightness of the welded portion P is maintained with the liquid stored in the internal space 3. As a result, it is possible to inspect whether the airtightness of the welded portion P is maintained by checking the presence or absence of bubbles B inside the liquid stored in the internal space 3, and it is possible to perform a more accurate inspection.

[0034] In this embodiment, the welded portion P is a part of a roof plate of a railway vehicle, and an airtightness confirmation device is used when inspecting whether the airtightness of the welded portion P of the roof plate of the railway vehicle is maintained. Some roof plates of railway vehicles have an uneven shape. Therefore, when inspecting whether the airtightness of the welded portion P is maintained in the roof plate of a railway vehicle, the inspection surface S of the welded portion P may have an uneven shape. In this embodiment, even if the inspection surface S of the welded portion P has an uneven shape, it is possible to inspect whether the airtightness of the welded portion P is maintained. Therefore, the airtightness confirmation device of this embodiment is suitable for inspecting whether the airtightness of the inspection surface S of the welded portion P of the roof plate of a railway vehicle having an uneven shape is maintained.

[0035] In the above embodiment, the transparent window 2b is located above the inspection surface S in the box body 2a of the box body 2, but the present invention is not limited to the above embodiment. FIG. 6 shows a side view of an airtightness checking device 1B in which a transparent window 19 is provided on a side surface 20 extending upward from the peripheral portion 5 of the opening 4 of the box body 2. As shown in FIG. 6, the transparent window 19 is provided on the side surface 20 located at the end of the box body 2 in the width direction D1. An inspector visually checks the state of the inside of the internal space 3 through the transparent window 19 from the outside of the box body 2 in the width direction D1, as if viewing the box body 2 from the side. In this way, the transparent window 19 does not have to be located above the inspection surface S, and the transparent window 19 does not have to be provided at a position facing the inspection surface S.

[0036] Depending on the shape of the inspection surface S of the welded portion P in the welded work W, it is possible that the welded work W is configured so that a part of the welded work W covers the inspection surface S from above. In such a case, if the airtightness confirmation device is configured such that a transparent window is disposed above the inspection surface S in the box body 2, it is possible that the inspection surface S is hidden by a part of the welded work W, and it is impossible to visually confirm the location of the occurrence of the air bubble B simply by looking at the transparent window from above the box body 2. Therefore, it is possible that it is impossible to confirm the location on the inspection surface S where airtightness is not maintained.

[0037] 6, by providing a transparent window 19 on the side surface 20 of the box body 2, even if a part of the welded workpiece W is configured to cover the inspection surface S from above, the position where the air bubble B has occurred can be visually confirmed through the transparent window 19. Therefore, even if a part of the welded workpiece W is configured to cover the inspection surface S, by checking the position where the air bubble B has occurred, it is possible to recognize where the airtightness is not maintained.

[0038] 6, when the transparent window 19 is provided on the side surface 20 of the box body 2, the air bubbles B do not move along the transparent window 19, so even if the air bubbles B accumulate above the transparent window 19, the visibility of the transparent window 19 is not reduced. Therefore, when the transparent window 19 is provided on the side surface 20 of the box body 2, the box body 2 or the transparent window 2b does not need to be inclined upward toward one side in the front-rear direction D2.

[0039] In the above embodiment, the vacuum port 10 is provided in the box 2 so as to communicate with the highest position of the internal space 3, and the vacuum port 10 is connected to the highest position of the box 2. However, the embodiment is not limited to the above embodiment. The vacuum port 10 may be provided in the box 2 so as to communicate with the internal space 3 at a position other than the highest position of the internal space 3. In addition, the vacuum port 10 does not have to be connected to the highest position of the box 2. When the air in the internal space 3 is discharged to the outside through the vacuum port 10 and the internal space 3 is evacuated, it is sufficient that no liquid flows into the vacuum port 10. Therefore, it is desirable that the vacuum port 10 is provided in the internal space 3 at a position above the space in which the liquid is expected to be stored. In addition, if it is desired to prevent the liquid from flowing into the vacuum port 10, the vacuum port 10 is provided at a position higher than the liquid supply port 12.

[0040] In the above embodiment, when the transparent window is provided at a position covering the upper side of the inspection surface S, the transparent window is inclined upward in one of the front and rear directions, but is not limited to the above embodiment. Even when the transparent window is provided at a position covering the upper side of the inspection surface S, it does not necessarily have to be inclined in order to check whether airtightness is maintained.

[0041] In the above embodiment, the support portion 2f protrudes toward the hole 2c only in the region A1 near the center of the width direction D1 of the box body main body 2a, but is not limited to the above embodiment. The support portion 2f may protrude toward the hole 2c only near either end of the box body main body 2a in the width direction D1. The support portion 2f may protrude toward the hole 2c at other positions. In addition, when air bubbles can accumulate in the support portion 2f, the support portion 2f may protrude toward the hole 2c over the entire region in the width direction D1.

[0042] In the above embodiment, the box body is provided with only one transparent window, but the present invention is not limited to the above embodiment. The box body may be provided with multiple transparent windows. In this case, for example, the transparent windows may be provided on both the surface of the box body that faces the inspection surface S and covers the upper side of the inspection surface S, and the side surface of the box body.

[0043] As described above, the above embodiment has been described as an example of the technology disclosed in this application. However, the technology in this disclosure is not limited to this, and can be applied to embodiments in which modifications, replacements, additions, omissions, etc. have been made as appropriate. In addition, it is also possible to combine the components described in the above embodiment to create a new embodiment. For example, a part of the configuration or method in one embodiment may be applied to another embodiment, and a part of the configuration in an embodiment can be separated from other configurations in that embodiment and arbitrarily extracted. In addition, the components described in the attached drawings and detailed description include not only components essential for solving the problem, but also components that are not essential for solving the problem in order to exemplify the technology.

[0044] Here, we will consider one modified example that adds a configuration for draining liquid from the box body. Another set of the vacuum device shown in this embodiment is prepared, and a new liquid drainage port is installed near the opposite side of the liquid supply port 12. The prepared vacuum device is connected to the liquid drainage port, and then to a hose, so that liquid can be drained from the hose. Furthermore, if the hose is connected to a liquid supply tank, the liquid can be circulated, which is economical. Even if there is no water facility near the work site, work can be done with just a tank full of water.

[0045] The procedure for draining the liquid is as follows. While maintaining the vacuum state of the internal space 3, the pressures of both ports are adjusted to a desired pressure difference so that the pressure of the drainage port is lower than the pressure of the vacuum port 10. This allows the liquid in the internal space to be sucked through the drainage port and drained from the internal space 3. That's it.

[0046] Each of the following sections is a disclosure of a preferred embodiment.

[0047] [Item 1] A device for checking airtightness of a welded portion that is placed on an inspection surface, a box defining an internal space together with the inspection surface and having an opening that opens the internal space; a packing that seals between the box body and the inspection surface, The box body is a periphery defining the opening; a transparent window that is disposed at a portion different from the peripheral portion and through which the inspection surface can be visually observed from the outside; A vacuum port that communicates with the internal space and is connected to a vacuum device; a liquid supply port communicating with the internal space and allowing a liquid to flow in; The packing is an airtightness checking device located on the peripheral edge portion or on the outer circumferential side of the peripheral edge portion.

[0048] [Item 2] 2. The airtightness confirmation device according to item 1, wherein the vacuum port is disposed on a vertically upward side of the box body.

[0049] [Item 3] 3. The airtightness confirmation device according to item 1 or 2, wherein the transparent window is disposed so as to face the opening.

[0050] [Item 4] 4. The airtightness confirmation device according to any one of items 1 to 3, wherein the peripheral portion of the box body has an uneven shape that matches the uneven shape of the inspection surface.

[0051] [Item 5] 5. The airtightness confirmation device according to any one of items 1 to 4, wherein the box has an air bubble reservoir protruding vertically upward.

[0052] [Item 6] 6. The airtightness confirmation device according to item 5, wherein the transparent window is inclined vertically upward as it approaches the air bubble reservoir.

[0053] [Item 7] the box body includes a box body main body portion having a hole that opens the internal space, and the transparent window that closes the hole and is separate from the box body main body portion, the box body portion has a support portion that receives the transparent window at an adjacent side of a periphery of the hole that is adjacent to the air bubble reservoir portion, 7. The airtightness confirmation device according to item 6, wherein the support portion partially protrudes from a part of the adjacent side of the peripheral portion of the hole toward the hole. [Item 8] 8. The airtightness confirmation device according to any one of items 1 to 7, wherein the box body has a protrusion protruding from an inner periphery of the periphery of the opening in a direction in which the packing is pressed against the inspection surface. [Explanation of symbols]

[0054] 1, 1A, 1B Airtightness Check Device 2 box body 2a Box body part 2b Transparent window 2c hole 2d Periphery 2e Adjacent Edge 2f Support part 3. Interior space 4 aperture 5 Periphery 5a Inner circumference 6. Packing 8 Protrusion 9 Bubble reservoir 10 Vacuum port 12 Fluid supply port 16 protrusions 18 Recess 19 Transparent Window B. Air bubbles S Inspection surface P Welding W Welded workpiece

Claims

1. A device for checking airtightness of a welded portion that is placed on an inspection surface, a box defining an internal space together with the inspection surface and having an opening that opens the internal space; a packing that seals between the box body and the inspection surface, The box body is a periphery defining the opening; a transparent window that is disposed at a portion different from the peripheral portion and through which the inspection surface can be visually observed from the outside; A vacuum port that communicates with the internal space and is connected to a vacuum device; a liquid supply port communicating with the internal space and allowing a liquid to flow in; The packing is an airtightness checking device located on the peripheral edge portion or on the outer circumferential side of the peripheral edge portion.

2. The airtightness checking device according to claim 1 , wherein the vacuum port is disposed on a vertically upward side of the box body.

3. 3. The airtightness checking device according to claim 1, wherein the transparent window is disposed so as to face the opening.

4. 3. The airtightness checking device according to claim 1, wherein the peripheral portion of the box has an uneven shape that matches the uneven shape of the inspection surface.

5. The airtightness checking device according to claim 1 or 2, wherein the box body has an air bubble trap portion that protrudes vertically upward.

6. 6. The airtightness checking device according to claim 5, wherein the transparent window is inclined vertically upward as it approaches the air bubble reservoir.

7. the box body includes a box body main body portion having a hole that opens the internal space, and the transparent window that closes the hole and is separate from the box body main body portion, the box body portion has a support portion that receives the transparent window at an adjacent side of a periphery of the hole that is adjacent to the air bubble reservoir portion, The airtightness confirmation device according to claim 6 , wherein the support portion partially protrudes from a part of the adjacent side of the peripheral edge of the hole toward the hole.

8. 3. The airtightness checking device according to claim 1, wherein the box body has a protrusion protruding from an inner periphery of the periphery of the opening in a direction in which the packing is pressed against the inspection surface.

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