Airtightness Testing Equipment

Abstract

To increase the precision of a test for airtightness of a pipe.SOLUTION: An airtightness testing apparatus (1) comprises: pipe fixing parts (10, 10A), which contact both ends of a pipe (T1) and press the ends in the axial direction of the pipe (T1) to fix the pipe (T1) at a predetermined position; and covering jigs (20, 20A), which cover the end parts of the pipe (T1). The covering jigs (20, 20A) have air inlet ports (21A, 21B), through which air is injected into the covering jigs (20, 20A).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an airtightness testing device. [Background technology]

[0002] Patent Document 1 discloses an airtightness testing device that includes a pipe fixing part for fixing a pipe in a predetermined position and a hood for covering the pipe. In this airtightness testing device, the pipe fixing part abuts against the end of the pipe via a packing, thereby improving the airtightness of the pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-77854 Summary of the Invention [Problem to be solved by the invention]

[0004] In the airtightness testing device disclosed in Patent Document 1, repeated airtightness testing can cause packing to wear down, which can allow the detection gas to enter the inside of the tube from the end of the tube. Therefore, there is room for improvement in the airtightness testing device in terms of improving the accuracy of the airtightness testing of the tube. One aspect of the present invention aims to improve the accuracy of the airtightness testing of the tube. [Means for solving the problem]

[0005] In order to solve the above problems, an airtightness testing device according to one embodiment of the present invention comprises a pipe fixing part that abuts against both ends of a pipe and presses the ends in the axial direction of the pipe to fix the pipe in a predetermined position, and a covering jig that covers the ends of the pipe, the covering jig having an air injection port formed therein through which air is injected into the interior of the covering jig. [Effects of the Invention]

[0006] According to one aspect of the present invention, the accuracy of airtightness testing of pipes can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing the overall configuration of an airtightness testing device according to a first embodiment of the present invention. [Figure 2] 2 is a perspective view showing the vicinity of a covering jig provided in the airtightness testing device shown in FIG. 1. FIG. [Figure 3] 2 is a diagram showing the configuration of a sealing member provided in the airtightness testing device shown in FIG. 1. FIG. [Figure 4] FIG. 10 is a perspective view showing the vicinity of a covering jig provided in an airtightness testing device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Embodiment 1] <Configuration of Airtightness Testing Device 1> Fig. 1 is a schematic diagram showing the overall configuration of an airtightness testing apparatus 1 according to a first embodiment of the present invention. Fig. 2 is a perspective view showing the vicinity of a covering jig 20 provided in the airtightness testing apparatus 1 shown in Fig. 1. In Fig. 1, the direction from the gas injector 50 toward the pipe T1 is defined as the Z-axis direction, the extension direction of the pipe T1 is defined as the X-axis direction, and the direction perpendicular to both the X-axis direction and the Z-axis direction is defined as the Y-axis direction.

[0009] The X-axis, Y-axis, and Z-axis directions are perpendicular to one another. The positive Z-axis direction is the upward direction, and the negative Z-axis direction is the downward direction. The definitions of the X-axis, Y-axis, and Z-axis directions described here also apply to figures other than FIG. 1. The vacuum pump 11P, the detection unit 12, and the hood 40 are omitted from FIG. 2.

[0010] The airtightness testing apparatus 1 is an apparatus for performing an airtightness test to test the airtightness of a pipe T1. The pipe T1 may be, for example, a ductile cast iron pipe. Furthermore, the pipe T1 is not necessarily limited to a ductile cast iron pipe, but may also be a metal pipe such as a steel pipe. As shown in FIG. 1 , the airtightness testing apparatus 1 includes pipe fixing units 10, 10A, a vacuum pump 11P, a detection unit 12, valves V1, V2, covering jigs 20, 20A, and sealing members 30A-30H. The airtightness testing apparatus 1 also includes a hood 40, a gas injector 50, a base 60, support rollers 61, and a cylinder 70.

[0011] <Configuration of pipe fixing portions 10, 10A and cylinder 70> The pipe fixing parts 10, 10A abut against both ends of the pipe T1 and press the ends in the axial direction of the pipe T1, thereby fixing the pipe T1 in a predetermined position. The axial direction of the pipe T1 is the X-axis direction. The pipe fixing part 10 has a fixing end 11, and the pipe fixing part 10A has a pressing end 11A. The fixing end 11 is fixed at a fixed position in the airtightness testing device 1.

[0012] One end of the pipe T1 is formed with a socket into which the socket of another pipe T1 can be inserted, and the other end of the pipe T1 is formed with a socket into which the socket of another pipe T1 can be inserted. The end T2 of the pipe T1 on the socket side abuts against the fixed end 11. Note that the pipe T1 formed with a socket and a socket is just one example, and the pipe T1 is not necessarily limited to one formed with a socket and a socket.

[0013] The pressing end 11A is connected to a rod 71 of the cylinder 70. As the rod 71 moves in the X-axis direction, the pressing end 11A moves in the X-axis direction relative to the fixed end 11. The insertion-side end T3 of the pipe T1 abuts against the pressing end 11A.

[0014] The cylinder 70 has a rod 71 and a cylindrical body 72. The rod 71 extends in the X-axis direction, and the cylindrical body 72 is capable of accommodating the rod 71. The cylinder 70 presses the tube fixing portions 10, 10A against both ends of the tube T1. Specifically, the cylinder 70 moves the rod 71 in the positive direction of the X-axis, thereby pressing the fixed end 11 against the end T2 of the tube T1 and pressing the pressing end 11A against the end T3 of the tube T1. As a result, the tube T1 is fixed in a predetermined position while being sandwiched between the fixed end 11 and the pressing end 11A.

[0015] Cylinder 70 is, for example, a fluid pressure cylinder that moves rod 71 in the X-axis direction by the fluid pressure of a fluid injected into cylindrical body 72. An example of the fluid pressure cylinder is a hydraulic cylinder. Cylinder 70 may also be an electric cylinder that electrically moves rod 71 in the X-axis direction.

[0016] The cylinder 70 presses the pipe fixing parts 10, 10A against both ends of the pipe T1, so that the pipe fixing parts 10, 10A can be strongly pressed against both ends of the pipe T1. This ensures sufficient airtightness between the pipe T1 and the pipe fixing parts 10, 10A, improving the accuracy of the airtightness test.

[0017] Fixed end 11 abuts against end T2 of tube T1 via packing P1, and pressing end 11A abuts against end T3 of tube T1 via packing P2. This prevents the detectable gas used to test the airtightness of tube T1 from entering the interior of tube T1 between fixed end 11 and tube T1, and also prevents it from entering the interior of tube T1 between pressing end 11A and tube T1. The detectable gas is a gas that exists in an extremely small proportion in the atmosphere, and specific examples of the detectable gas include He (helium) and Ar (argon).

[0018] Furthermore, a through-hole 16 is formed in the fixed end 11, penetrating from the surface facing the tube T1 to the surface opposite that surface. When the tube T1 abuts against the fixed end 11, the through-hole 16 communicates with the interior of the tube T1. Note that the end T3 of the tube T1 may abut against the fixed end 11, and the end T2 of the tube T1 may abut against the pressing end 11A.

[0019] <Configuration of vacuum pump 11P and detection unit 12> The vacuum pump 11P is a pump that creates a vacuum inside the pipe T1. A pipe 14 is connected to the vacuum pump 11P, and a valve V1 is provided on the pipe 14. The pipe 14 is connected to another pipe 13. A portion of the pipe 13 is disposed inside the through-hole 16. When the valve V1 is open, the vacuum pump 11P communicates with the inside of the pipe T1 via the pipe 13 and the pipe 14.

[0020] The detection unit 12 detects the detection gas inside the pipe T1. An example of the detection unit 12 is an analyzer that analyzes the components of a gas. A pipe 15 is connected to the detection unit 12, and a valve V2 is provided on the pipe 15. The pipe 15 is connected to the pipe 13. That is, the pipes 14 and 15 merge into the pipe 13. When the valve V2 is open, the detection unit 12 communicates with the inside of the pipe T1 via the pipes 13 and 15.

[0021] <Configuration of covering jigs 20, 20A> The covering jig 20 covers an end T2 of the pipe T1 fixed by the pipe fixing parts 10, 10A, and the covering jig 20A covers an end T3 of the pipe T1 fixed by the pipe fixing parts 10, 10A. As shown in Fig. 2, air injection ports 21A, 21B, 21C, and 21D for injecting air into the covering jig 20 are formed on a side surface 25 of the covering jig 20.

[0022] The interior of the covering jig 20 is a space defined by the covering jig 20, the pipe T1, and the pipe fixing part 10. The covering jig 20 is further formed with an air exhaust port (not shown) for exhausting air from the interior of the covering jig 20. This allows the concentration of the detection gas inside the covering jig 20 to be reduced.

[0023] Tubes 22A, 22B, 22C, and 22D are connected to the air inlets 21A to 21D, respectively. Air is injected into the interior of the covering jig 20 via the air inlets 21A to 21D and the tubes 22A to 22D. The covering jig 20A has the same configuration as the covering jig 20, except that it covers the end T3 of the tube T1. For this reason, in the following explanation, only the covering jig 20 will be explained, and an explanation of the covering jig 20A will be omitted.

[0024] The covering jig 20 has a ring shape because it covers the end T2 of the pipe T1. When the covering jig 20 is cut along a plane perpendicular to the X-axis direction, the cross-sectional shape of the covering jig 20 is circular. The cross-sectional shape of the covering jig 20 may be rectangular. The covering jig 20 may also be formed by combining at least two partial covering jigs. The partial covering jigs cover different areas in the circumferential direction of the pipe T1. The areas covered by each of the partial covering jigs are in contact with each other.

[0025] The covering jig 20 has a front surface 24 perpendicular to the X-axis direction and a side surface 25 extending in the positive direction of the X-axis from the outer peripheral end of the front surface 24. The side surface 25 is fixed to the pipe fixing part 10, and the end of the side surface 25 on the negative X-axis direction side is connected to the front surface 24. A first insertion hole 23 is formed in the front surface 24, through which the pipe T1 is inserted.

[0026] <Configuration of Seal Members 30A to 30D> Fig. 3 is a diagram showing the configuration of sealing members 30A, 30B, 30C, and 30D provided in the airtightness testing apparatus 1 shown in Fig. 1. The diagram indicated by reference numeral 101 in Fig. 3 is a front view showing the configuration of the sealing member 30A, and the diagram indicated by reference numeral 102 in Fig. 3 is a cross-sectional view showing the cross-sectional configuration of the sealing members 30A to 30D taken along dotted line L1 of reference numeral 101 in Fig. 3.

[0027] The sealing members 30E, 30F, 30G, and 30H provided in the covering jig 20A have the same configuration as the sealing members 30A to 30D, respectively. Therefore, in the following description, only the sealing members 30A to 30D will be described, and a description of the sealing members 30E to 30H will be omitted.

[0028] 1 and 2, the seal members 30A to 30D are provided in the first insertion hole 23 and seal between the pipe T1 and the first insertion hole 23. The material of the seal members 30A to 30D is, for example, rubber such as NBR (acrylonitrile butadiene rubber), but is not limited thereto and may be a resin material such as silicone. When the pipe T1 is inserted into the covering jig 20, the seal members 30A to 30D are inclined toward the inside of the covering jig 20.

[0029] As indicated by reference numeral 101 in Fig. 3, the seal member 30A has an annular shape. The seal members 30B to 30D have the same shape as the seal member 30A. The seal members 30A to 30D are arranged so as to overlap one another in the X-axis direction. In other words, a plurality of seal members are arranged so as to overlap one another in the X-axis direction.

[0030] The seal members 30A to 30D are each formed with a second insertion hole 31A, 31B, 31C, and 31D through which the pipe T1 is inserted. As indicated by reference numeral 102 in FIG. 3, the second insertion holes 31A to 31D are each formed with a plurality of notches 32A, 32B, 32C, and 32D. To ensure sufficient airtightness between the pipe T1 and the first insertion hole 23, it is preferable that the inner diameter of the second insertion holes 31A to 31D be smaller than the outer diameter of the pipe T1. In this embodiment, the terms "inner diameter" and "outer diameter" refer to diameters. Note that a single seal member 30A may be provided in the first insertion hole 23.

[0031] The inner diameters of the second insertion holes 31A-31D may be different from one another. For example, as shown in FIG. 1, consider a case where a sloped portion T4 is formed near the end T2 of the tube T1 so that the outer diameter increases from near the center of the tube T1 toward the end T2 of the tube T1. In this case, it is preferable that the inner diameters of the second insertion holes 31A-31D increase in the order of 31A, 31B, 31C, and 31D. This allows the force applied to the tube T1 from each of the sealing members 30A-30D to be uniform, preventing localized difficulty in removing the tube T1 from the covering jig 20.

[0032] By providing the seal members 30A to 30D in the first insertion holes 23, it is possible to prevent the detection gas from flowing into the covering jig 20 from near the center of the tube T1, and also to prevent air from leaking from the inside of the covering jig 20 to near the center of the tube T1. Preventing the detection gas from flowing into the covering jig 20 from near the center of the tube T1 improves the accuracy of the airtightness test.

[0033] In addition, by preventing air from leaking from inside the covering jig 20 to near the center of the tube T1, the detection gas near the covering jig 20 can be prevented from being blown away by air, so the area near the covering jig 20 can also be included in the test range of the tube T1, and the untested area of ​​the tube T1 can be reduced.

[0034] Furthermore, by forming a plurality of notches 32A to 32D in the second insertion holes 31A to 31D of the sealing members 30A to 30D, it is possible to reduce settling of the sealing members 30A to 30D when inserting or removing the tube T1 into or from the covering jig 20. Furthermore, it is possible to reduce the force required to insert or remove the tube T1 into or from the covering jig 20, making it easier to remove the tube T1.

[0035] Since the wear of the sealing members 30A to 30D can be reduced, the sealing members 30A to 30D can be used repeatedly. Furthermore, by providing the sealing members 30A to 30D in the first insertion holes 23, the gap between the first insertion holes 23 and the pipe T1 is blocked by the sealing members 30A to 30D. This makes it possible to accommodate variations in the dimensions or shapes of the pipe T1, and also to accommodate various diameters and types of pipe T1.

[0036] The sealing members 30A to 30D are disposed inside the covering jig 20. Air is injected into the covering jig 20 through the air injection ports 21A to 21D. This causes the sealing members 30A to 30D to tightly contact the pipe T1 due to the pressure inside the covering jig 20. This effectively improves the airtightness between the pipe T1 and the first insertion hole 23.

[0037] In at least one pair of adjacent seal members, the plurality of notches formed in one seal member are offset in the circumferential direction D1 of the pipe T1 from the plurality of notches formed in the other seal member. The "at least one pair of adjacent seal members" refers to at least one of the pair of seal members 30A and 30B, the pair of seal members 30B and 30C, or the pair of seal members 30C and 30D.

[0038] For example, consider the adjacent seal members 30A and 30B indicated by reference numerals 101 and 102 in Fig. 3. The multiple notches 32A formed in one seal member 30A are offset in the circumferential direction D1 of the pipe T1 from the multiple notches 32B formed in the other seal member 30B. In Fig. 3, the dotted line of the notches 32B indicates that the notches 32B are positioned further toward the positive side of the X-axis than the seal member 30A.

[0039] In non-adjacent seal members 30A, 30C, the positions of the multiple notches 32A may coincide with the positions of the multiple notches 32C in the circumferential direction D1 of the pipe T1. This is because, even if the positions of the notches 32A and 32C coincide with each other, the arrangement of the seal member 30B between the seal members 30A, 30C can sufficiently ensure airtightness between the pipe T1 and the first insertion hole 23.

[0040] With the above configuration, when inserting or removing the pipe T1 into or from the covering jig 20, it is possible to reduce the force required to insert or remove the pipe T1 into or from the covering jig 20. Furthermore, since the force applied to the seal members 30A to 30D can be reduced, it is possible to reduce the settling of the seal members 30A to 30D.

[0041] Furthermore, in at least one pair of adjacent seal members, the notch formed in one seal member is misaligned with the notch formed in the other seal member, thereby improving the airtightness between the pipe T1 and the first insertion hole 23.

[0042] <Configuration of the hood 40 and the gas injector 50> As shown in Fig. 1, the hood 40 covers the pipe T1 fixed to the pipe fixing parts 10, 10A. The hood 40 is suspended by a plurality of chains (not shown). With the hood 40 covering the pipe T1, the gas injector 50 injects the detection gas into the space between the hood 40 and the outer surface of the pipe T1.

[0043] Gas injector 50 has a gas injection pipe 51 for injecting detection gas into the space between hood 40 and the outer surface of pipe T1. When hood 40 covers pipe T1, the open end of gas injection pipe 51 is positioned higher than the lower end of hood 40 and not in contact with the outer surface of pipe T1. However, the position of the open end of gas injection pipe 51 is not limited to this.

[0044] <Configuration of the base 60 and the support roller 61> Each of the plurality of pedestals 60 is provided with a support roller 61. The support roller 61 supports the tube T1. The tube T1 supported by the support rollers 61 can move in the X-axis direction by the rotation of the support rollers 61.

[0045] Consider a case where the cylinder 70 moves the rod 71 in the positive direction of the X axis while the support roller 61 rotates clockwise with respect to the positive direction of the Y axis. In this case, the frictional force generated between the tube T1 and the support roller 61 allows the tube T1 to be inserted into the covering jig 20 and the end T2 of the tube T1 to be pressed against the fixed end 11. Furthermore, if the cylinder 70 moves the rod 71 in the negative direction of the X axis while the support roller 61 rotates counterclockwise with respect to the positive direction of the Y axis, the frictional force generated between the tube T1 and the support roller 61 allows the tube T1 to be pulled out of the covering jig 20.

[0046] Support roller 61 may be movable in the Z-axis direction according to the outer diameter of pipe T1 or the progress of the airtightness test. In this case, the support roller 61 resting surface of base 60 is raised and lowered by a motor (not shown).

[0047] <Pulling mechanism for tube T1> The airtightness testing device 1 may include a pulling mechanism (not shown) for pulling the pipe T1 out of the covering jig 20. For example, the pulling mechanism has a clamping portion that clamps the pipe T1, and pulls the pipe T1 out of the covering jig 20 by moving the clamping portion in the negative direction of the X-axis while the clamping portion is clamping the pipe T1.

[0048] Now, consider the case where the pipe T1 having the inclined portion T4 formed thereon is pulled out from the covering jig 20. In this case, even if the force applied to the pipe T1 from the sealing members 30A-30D is strong due to the formation of the inclined portion T4 and the force required to pull out the pipe T1 is large, the pipe T1 can be pulled out from the covering jig 20 by the above-described pulling mechanism.

[0049] In this embodiment, air is injected into the covering jig 20 through air injection ports 21A to 21D formed in the covering jig 20 that covers the end T2 of the tube T1, thereby increasing the pressure inside the covering jig 20. This makes it difficult for the detection gas used in the airtightness test to flow into the covering jig 20. This makes it difficult for the detection gas present around the end T2 of the tube T1 to flow from the end T2 of the tube T1 into the inside of the tube T1. This can improve the accuracy of the airtightness test.

[0050] [Embodiment 2] A second embodiment of the present invention will be described below. For ease of explanation, members having the same functions as those described in the first embodiment will be denoted by the same reference numerals, and their description will not be repeated. Fig. 4 is a perspective view showing the vicinity of a covering jig 20B provided in an airtightness testing device 1A according to the second embodiment of the present invention. Fig. 4 omits the pipe T1, the vacuum pump 11P, the detection unit 12, the front surface 24 of the covering jig 20B, and the hood 40.

[0051] 4, the airtightness testing apparatus 1A differs from the airtightness testing apparatus 1 in that it includes a covering jig 20B instead of the covering jig 20. The covering jig 20B differs from the covering jig 20 in that a plurality of covering members 27 are provided on an inner circumferential surface 26 of the covering jig 20B. The inner circumferential surface 26 is the rear surface of the side surface 25. The tubes 22A to 22D are connected to openings A1, A2, A3, and A4 formed on the side surface 25 of the covering jig 20B, respectively.

[0052] Each of the multiple covering members 27 covers a corresponding one of the openings A1 to A4 inside the covering jig 20B. The air inlet ports 21A to 21D are formed between the covering member 27 and the inner circumferential surface 26. As a result, the air inlet ports 21A to 21D are formed in the covering jig 20B so as to guide the air injected into the interior of the covering jig 20B in a direction away from the sealing members 30A to 30D after being injected from the air inlet ports 21A to 21D, or in a direction along the boundary between the pipe T1 and the sealing members 30A to 30D.

[0053] The direction along the boundary between the pipe T1 and the sealing members 30A-30D is the circumferential direction D1 of the pipe T1. Furthermore, the direction in which air moves away from the sealing members 30A-30D after being injected through the air injection ports 21A-21D is a direction that passes through the positions of the air injection ports 21A-21D and heads toward the region between the pipe fixing part 10 and a plane perpendicular to the X-axis direction.

[0054] After being injected into the covering jig 20B through the air injection ports 21A-21D, the air is guided in a direction away from the sealing members 30A-30D or along the boundary between the pipe T1 and the sealing members 30A-30D. Therefore, the air is not guided in a direction that moves the sealing members 30A-30D away from the outer peripheral surface of the pipe T1. This improves the airtightness between the pipe T1 and the first insertion hole 23.

[0055] Example 1 In Example 1 of the present invention, an airtightness test was conducted under first and second test conditions using the airtightness test device 1 shown in Fig. 1. The results of the airtightness test are shown in Table 1 below. In Table 1, the presence or absence of air refers to the presence or absence of air injected into the covering jig 20 from the air injection ports 21A to 21D, and the average amount of He inflow is the average of the results of measuring the amount of He flowing into the covering jig 20 from near the center of the pipe T1 three times. The average amount of He inflow shown in Table 1 is 10 -10 MPa m 3 The unit is / s.

[0056] [Table 1]

[0057] The first test condition was that the sealing members 30A to 30D were not provided in the airtightness test device 1, and the gap between the pipe T1 and the covering jig 20 was 30 mm. When air was not injected under the first test condition, that is, when the pressure inside the covering jig 20 was 0 MPa, the amount of He inflow was measured three times, and the average value of the amount of He inflow was 191,000.

[0058] Furthermore, when air was injected under the first test condition, that is, when the pressure inside the coating jig 20 was air pressure, the amount of He inflow was measured three times, and the average value of the amount of He inflow was 33,000. Therefore, by injecting air into the coating jig 20, the amount of He flowing into the coating jig 20 could be reduced.

[0059] The second test condition was that the inner diameter of the second insertion holes 31A-31D of the sealing members 30A-30D in the airtightness test apparatus 1 was 232 mm, and the outer diameter of the pipe T1 was 236 mm. Here, outer diameter refers to the diameter. When air was not injected under the second test condition, that is, when the internal pressure of the covering jig 20 was 0 MPa, the amount of He inflow was measured three times, and the average value of the amount of He inflow was 2165. When air was injected under the second test condition, that is, when the internal pressure of the covering jig 20 included air pressure, the average value of the amount of He inflow was measured three times, and the average value of the amount of He inflow was 113.

[0060] Therefore, by reducing the inner diameters of the second insertion holes 31A to 31D, it is possible to further reduce the amount of He that flows into the covering jig 20. As described above, by injecting air into the covering jig 20 and improving the airtightness between the pipe T1 and the first insertion hole 23, it is possible to stably reduce the amount of He that flows into the covering jig 20.

[0061] 〔summary〕 The airtightness testing device according to aspect 1 of the present invention comprises a pipe fixing part that contacts both ends of a pipe and presses the ends in the axial direction of the pipe to fix the pipe in a predetermined position, and a covering jig that covers the ends of the pipe, the covering jig having an air injection port formed therein through which air is injected into the interior of the covering jig.

[0062] The airtightness testing device according to aspect 2 of the present invention may be configured in the above-mentioned aspect 1 such that the covering jig has a first insertion hole through which the pipe is inserted, a second insertion hole through which the pipe is inserted, and further includes a sealing member that seals between the pipe and the first insertion hole, and the second insertion hole has multiple notches formed therein.

[0063] An airtightness testing device according to aspect 3 of the present invention may be configured such that, in the above-mentioned aspect 2, the sealing members are arranged in multiple positions so as to overlap each other in the axial direction, and in at least one pair of adjacent sealing members, each of the multiple notches formed in one of the sealing members is offset circumferentially from the multiple notches formed in the other of the sealing members.

[0064] The airtightness testing device according to aspect 4 of the present invention may be configured such that, in the above-mentioned aspect 2 or 3, the air injection port is formed on the covering jig so as to guide the air injected into the interior of the covering jig in a direction away from the sealing member after being injected from the air injection port, or in a direction along the boundary between the pipe and the sealing member.

[0065] The airtightness testing device according to a fifth aspect of the present invention may be configured in any one of the first to fourth aspects, further comprising a cylinder that presses the pipe fixing portion against both ends of the pipe.

[0066] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0067] 1. 1A Airtightness Testing Device 10, 10A pipe fixing part 20, 20A, 20B Covering jig 21A~21D Air inlet 23 First insertion hole 30A~30H sealing material 31A~31D Second insertion hole 32A~32D Notch 70 cylinders D1 Circumferential direction T1 tube T2, T3 ends

Claims

1. a pipe fixing portion that abuts against both ends of the pipe and presses the both ends in the axial direction of the pipe to fix the pipe at a predetermined position; a coating jig for coating the end of the pipe, the covering jig is formed with an air inlet through which air is injected into the covering jig, and a first insertion hole through which the tube is inserted; a second insertion hole through which the pipe is inserted, and a seal member that seals between the pipe and the first insertion hole; The airtightness testing device is characterized in that the second insertion hole has a plurality of notches formed therein.

2. A plurality of the sealing members are arranged so as to overlap each other in the axial direction, 2. The airtightness testing device according to claim 1, wherein in at least one pair of adjacent seal members, each of the plurality of notches formed in one of the seal members is offset in the circumferential direction of the pipe from the plurality of notches formed in the other of the seal members.

3. 3. The airtightness testing device according to claim 1, wherein the air inlet is formed in the covering jig so as to guide the air to be injected into the covering jig in a direction away from the sealing member after being injected from the air inlet, or in a direction along the boundary between the pipe and the sealing member.

4. 3. The airtightness testing device according to claim 1, further comprising a cylinder for pressing the pipe fixing portion against both ends of the pipe.

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