JP7412623B1 - Airtightness test equipment - Google Patents

Abstract

An object of the present invention is to reduce the sagging of a sealing member when the pipe is inserted into and removed from a covering jig, in order to improve the accuracy of airtightness tests for pipes. [Solution] The airtightness test device (1) includes a tube fixing part (10, 10A) that fixes the tube (T1) at a predetermined position, and an air-tightness tester that covers the end of the tube (T1) and into which air is injected. Covering jigs (20, 20A) each having an injection port (21A, 21B) and a first insertion hole (23) into which the tube (T1) is inserted are arranged so as to overlap each other in the axial direction. It includes a plurality of seal members (30A to 30H) that seal between the tube (T1) and the first insertion hole (23). [Selection diagram] Figure 1

Description

The present invention relates to an airtightness test device.

Patent Document 1 discloses an airtightness testing device that includes a tube fixing part for fixing a tube at a predetermined position and a hood for covering the tube. In this airtightness testing device, the tube fixing portion abuts against the end of the tube via the packing, thereby improving the airtightness of the tube.

Japanese Patent Application Publication No. 2022-77854

In the airtightness test device disclosed in Patent Document 1, the detection gas may enter the inside of the tube from the end of the tube due to the influence of the packing being worn out due to repeated airtightness tests. Therefore, there is room for improvement in the airtightness test device in terms of improving the accuracy of the airtightness test for pipes. One aspect of the present invention aims to reduce the sag of a sealing member when a pipe is inserted into and removed from a covering jig, in order to improve the accuracy of airtightness tests for pipes.

In order to solve the above problems, an airtightness test device according to one aspect of the present invention fixes the tube in a predetermined position by abutting both ends of the tube and pressing the both ends in the axial direction of the tube. a tube fixing part, a coating jig for coating the end of the tube, an air injection port through which air is injected into the coating jig, and a first insertion hole through which the tube is inserted; and a plurality of seal members that are arranged to overlap each other in the axial direction and seal between the pipe and the first insertion hole.

According to one aspect of the present invention, in order to improve the accuracy of airtightness tests for pipes, it is possible to reduce sagging of the sealing member when the pipe is inserted into and removed from the covering jig.

1 is a schematic diagram showing the overall configuration of an airtightness testing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing the vicinity of a covering jig included in the airtightness testing apparatus shown in FIG. 1. FIG. FIG. 2 is a diagram showing the configuration of a sealing member included in the airtightness testing apparatus shown in FIG. 1 and the configuration near the fixed end of a tube fixing part. FIG. 7 is a perspective view showing the vicinity of a covering jig included in the airtightness testing apparatus according to Embodiment 2 of the present invention.

[Embodiment 1]
<Configuration of airtightness test device 1>
FIG. 1 is a schematic diagram showing the overall configuration of an airtightness testing apparatus 1 according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing the vicinity of the covering jig 20 included in the airtightness testing apparatus 1 shown in FIG. In FIG. 1, the direction from the gas injector 50 toward the tube T1 is the Z-axis direction, the direction in which the tube T1 extends is the X-axis direction, and the direction perpendicular to both the X-axis direction and the Z-axis direction is the Y-axis direction.

The X-axis direction, the Y-axis direction, and the Z-axis direction are directions orthogonal to each other. The Z-axis positive direction is upward, and the Z-axis negative direction is downward. The definitions of the X-axis direction, Y-axis direction, and Z-axis direction explained here are also applied to other figures other than FIG. 1. In FIG. 2, the vacuum pump 11P, the detection unit 12, and the hood 40 are omitted.

The airtightness test device 1 is a device for performing an airtightness test to test the airtightness of the tube T1. An example of the pipe T1 is a ductile cast iron pipe. Further, the pipe T1 is not necessarily limited to a ductile cast iron pipe, but may be a metal pipe such as a steel pipe. As shown in FIG. 1, the airtightness test device 1 includes tube fixing parts 10, 10A, a vacuum pump 11P, a detection part 12, valves V1, V2, covering jigs 20, 20A, and a plurality of seal members 30A. ~30H. The airtightness test device 1 also includes a hood 40, a gas injector 50, a pedestal 60, a support roller 61, and a cylinder 70.

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

A socket into which the socket of another pipe T1 can be inserted is formed at one end of the tube T1, and an socket into which the socket of another pipe T1 can be inserted is formed at the other end of the pipe T1. . The fixed end 11 is brought into contact with the socket-side end T2 of the tube T1. Note that the tube T1 in which an insertion port and a socket are formed is one example, and the tube T1 is not necessarily limited to one in which an insertion port and a socket are formed.

The pressing end 11A is connected to the rod 71 of the cylinder 70. By moving the rod 71 in the X-axis direction, the pressing end 11A moves in the X-axis direction with respect to the fixed end 11. An end T3 of the tube T1 on the insertion side comes into contact with the pressing end 11A.

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 can accommodate the rod 71. The cylinder 70 presses the tube fixing parts 10 and 10A against both ends of the tube T1. Specifically, by moving the rod 71 in the positive direction of the X-axis, the cylinder 70 presses the fixed end 11 against the end T2 of the tube T1 and presses the pressing end 11A against the end T3 of the tube T1. . Thereby, the tube T1 is fixed at a predetermined position while being held between the fixed end 11 and the pressing end 11A.

The cylinder 70 is, for example, a fluid pressure cylinder that moves the rod 71 in the X-axis direction by the fluid pressure of fluid injected into the cylindrical body 72. Examples of the fluid pressure cylinder include a hydraulic cylinder. Further, the cylinder 70 may be an electric cylinder that electrically moves the rod 71 in the X-axis direction.

Since the cylinder 70 presses the tube fixing parts 10 and 10A against both ends of the tube T1, the tube fixing parts 10 and 10A can be strongly pressed against both ends of the tube T1. Therefore, the airtightness between the tube T1 and the tube fixing parts 10, 10A can be sufficiently ensured, and the accuracy of the airtightness test can be improved.

The fixed end 11 contacts the end T2 of the tube T1 via the packing P1, and the pressing end 11A contacts the end T3 of the tube T1 via the packing P2. Therefore, the detection gas used when testing the airtightness of the tube T1 is prevented from entering the inside of the tube T1 from between the fixed end 11 and the tube T1, and from between the pressing end 11A and the tube T1. It can be prevented from entering the inside of the tube T1. The detection gas is a gas whose abundance ratio in the atmosphere is extremely small, and specific examples of the detection gas include He (helium) and Ar (argon).

Furthermore, a through hole 16 is formed in the fixed end 11, passing through from the surface facing the tube T1 to the surface opposite to the surface. When the tube T1 is in contact with the fixed end 11, the through hole 16 communicates with the inside of the tube T1. Note that the end T3 of the tube T1 may be in contact with the fixed end 11, and the end T2 of the tube T1 may be in contact with the pressing end 11A.

<Configuration of vacuum pump 11P and detection unit 12>
The vacuum pump 11P is a pump that evacuates the inside of the tube T1. A pipe 14 is connected to the vacuum pump 11P, and the pipe 14 is provided with a valve V1. Piping 14 is connected to another piping 13. A portion of the pipe 13 is arranged 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.

The detection unit 12 detects the detection gas inside the tube T1. The detection unit 12 may be, for example, an analyzer that analyzes gas components. A pipe 15 is connected to the detection unit 12, and the pipe 15 is provided with a valve V2. Piping 15 is connected to piping 13. In other words, the pipe 14 and the pipe 15 join the pipe 13. When the valve V2 is open, the detection unit 12 communicates with the inside of the pipe T1 via the pipe 13 and the pipe 15.

<Configuration of coating jig 20, 20A>
The covering jig 20 covers the end T2 of the tube T1 fixed by the tube fixing parts 10, 10A, and the covering jig 20A covers the end T2 of the pipe T1 fixed by the tube fixing parts 10, 10A. This covers T3. As shown in FIG. 2, air injection ports 21A, 21B, 21C, and 21D through which air is injected into the coating jig 20 are formed in the side surface 25 of the coating jig 20.

The inside of the covering jig 20 is a space defined by the covering jig 20, the pipe T1, and the pipe fixing part 10. Further, the coating jig 20 is further formed with an air discharge port (not shown) for discharging air from inside the coating jig 20. Thereby, the concentration of the detection gas inside the coating jig 20 can be lowered.

Tubes 22A, 22B, 22C, and 22D are connected to the air inlets 21A to 21D, respectively. Air is injected into the coating jig 20 through 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 pipe T1. Therefore, in the following description, only the covering jig 20 will be described, and the description of the covering jig 20A will be omitted.

Since the covering jig 20 covers the end T2 of the tube T1, the shape of the covering jig 20 is annular. The cross-sectional shape of the covering jig 20 when the covering jig 20 is cut along a plane perpendicular to the X-axis direction is circular. Note that the cross-sectional shape of the covering jig 20 may be rectangular. Further, the covering jig 20 may be configured by combining at least two partial covering jigs. The partial covering jig covers mutually different ranges in the circumferential direction of the pipe T1. The ranges covered by the respective partial covering jigs are in contact with each other.

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

<Configuration of seal members 30A to 30D>
FIG. 3 is a diagram showing the configuration of the seal member 30A included in the airtightness testing apparatus 1 shown in FIG. 1 and the configuration near the fixed end 11 of the tube fixing part 10. The figure 101 in FIG. 3 is a front view showing the configuration of the sealing member 30A, and the figure 102 in FIG. 3 is a sectional view showing the configuration near the fixed end 11 of the tube fixing part 10. The drawing indicated by reference numeral 102 in FIG. 3 omits the coating jig 20, the seal members 30A to 30D, and the hood 40.

Seal members 30E, 30F, 30G, and 30H provided on coating jig 20A each have the same configuration as seal members 30A to 30D. Therefore, in the following description, only the seal members 30A to 30D will be described, and the description of the seal members 30E to 30H will be omitted.

As shown in FIGS. 1 and 2, the seal members 30A to 30D are provided in the first insertion hole 23 and seal between the tube T1 and the first insertion hole 23. When inserting the tube T1 into the coating jig 20, the seal members 30A to 30D are inclined toward the inside of the coating jig 20. The material of the sealing members 30A to 30D is silicone resin such as silicone rubber, urethane, or natural rubber, and silicone resin is particularly preferred.

When the material of the seal members 30A to 30D is silicone resin, the strength of the seal member is made sufficient by stacking a plurality of seal members on top of each other as described later, and there is a gap between the seal members 30A to 30D and the pipe T1. The generated frictional force can be made sufficiently small. Therefore, the force required to insert and remove the tube T1 into and from the coating jig 20 can be reduced, and when the tube T1 is inserted and removed from the coating jig 20, the force required to insert and remove the tube T1 from the coating jig 20 can be reduced. This makes it possible to sufficiently reduce the amount of damage and facilitate the removal of the tube T1.

Furthermore, since the frictional force generated between the sealing members 30A to 30D and the tube T1 can be sufficiently reduced, the tube T1 can be pulled out from the coating jig 20 by rotating the support roller 61 counterclockwise with respect to the positive direction of the Y-axis. be able to.

As shown by reference numeral 101 in FIG. 3, the seal member 30A has an annular shape. A second insertion hole 31A through which the tube T1 is inserted is formed in the seal member 30A. Let L1 be the diameter of the second insertion hole 31A in a state where the second insertion hole 31A is open. The state in which the second insertion hole 31A is open is a state in which the tube T1 is not inserted into the second insertion hole 31A.

Further, as shown by reference numeral 102 in FIG. 3, the outer diameter of the tube T1 at the end T2 of the tube T1 is L2. In this case, the diameter L1 of the second insertion hole 31A is smaller than the outer diameter L2 of the tube T1 at the end T2. In this embodiment, the outer diameter means the diameter. As an example, when the outer diameter L2 of the tube T1 is 230 mm, the diameter L1 of the second insertion hole 31A is, for example, 215 mm or more and 220 mm or less.

Since the diameter L1 of the second insertion hole 31A is smaller than the outer diameter L2 of the tube T1, when the tube T1 is inserted into the second insertion hole 31A, the sealing member 30A can be brought into close contact with the tube T1. Therefore, it is possible to more effectively reduce the detection gas flowing into the coating jig 20 from around the center of the tube T1 in the X-axis direction.

The shapes of the seal members 30B to 30D are the same as the shape of the seal member 30A. As shown in FIG. 1, similarly to the seal member 30A, the seal member 30B is formed with a second insertion hole 31B through which the tube T1 is inserted. Further, the sealing member 30C is formed with a second insertion hole 31C through which the tube T1 is inserted, and the sealing member 30D is formed with a second insertion hole 31D through which the tube T1 is inserted. The seal members 30A to 30D are arranged to overlap each other in the X-axis direction. That is, a plurality of seal members are arranged so as to overlap each other in the X-axis direction.

The sealing member 30A is an elastic member that elastically deforms and comes into close contact with the tube T1 when the tube T1 is inserted into the second insertion hole 31A. The seal member 30B is an elastic member that elastically deforms and comes into close contact with the tube T1 when the tube T1 is inserted into the second insertion hole 31B. Similarly, the seal members 30C and 30D are also elastic members that are elastically deformed and come into close contact with the pipe T1.

Each of the plurality of seal members 30A to 30D is an elastic member that elastically deforms and comes into close contact with the tube T1, so that the tube T1 and the first insertion hole 23 can be connected to each other without fixing the tube T1 to the first insertion hole 23. It is possible to seal between. Therefore, since the tube T1 can be easily inserted into and removed from the coating jig 20, the airtightness test can be performed by easily replacing the tube T1.

As an example, the thickness of each of the seal members 30A to 30D is, for example, 1 mm. In this case, by arranging the four seal members 30A to 30D so as to overlap each other in the X-axis direction, the thickness of the seal member group made up of the seal members 30A to 30D becomes 4 mm. As another example, the airtightness test device 1 may not include the seal member 30D, and the thickness of each of the seal members 30A to 30C may be 3 mm. In this case, by arranging the three seal members 30A to 30C so as to overlap each other in the X-axis direction, the thickness of the seal member group consisting of the seal members 30A to 30C becomes 9 mm.

It is preferable that the number of sealing members provided in the first insertion hole 23 is two or more. Thereby, it is possible to sufficiently maintain airtightness between the tube T1 and the first insertion hole 23, and even if one sealing member is torn, another sealing member can be used to maintain airtightness. can be maintained.

Further, the diameters of the second insertion holes 31A to 31D may be different from each other. For example, as shown in FIG. 1, when 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. think of. In this case, it is preferable that the diameters of the second insertion holes 31A to 31D increase in the order of the second insertion holes 31A, 31B, 31C, and 31D. Thereby, the force applied to the tube T1 from each of the seal members 30A to 30D can be made constant, and it is possible to prevent the tube T1 from becoming locally difficult to pull out from the covering jig 20.

By providing the seal members 30A to 30D in the first insertion hole 23, it is possible to prevent the detection gas from flowing into the coating jig 20 from around the center of the tube T1, and to prevent air from flowing into the coating jig 20. It is possible to prevent leakage from the inside of the tube to the vicinity of the center of the tube T1. By preventing the detection gas from flowing into the coating jig 20 from around the center of the tube T1, the accuracy of the airtightness test can be improved.

Furthermore, by preventing air from leaking from inside the covering jig 20 to the vicinity of the center of the tube T1, it is possible to prevent the detection gas near the covering jig 20 from being blown away by the air. The vicinity can also be set as the test range of the tube T1, and the untested range of the tube T1 can be made small.

Further, by providing the seal members 30A to 30D in the first insertion hole 23, the gap between the first insertion hole 23 and the tube T1 is closed by the seal members 30A to 30D. Therefore, it is possible to accommodate variations in dimensions or shapes of the tube T1, and it is also possible to accommodate various diameters and types of the tube T1.

The seal members 30A to 30D are arranged inside the coating jig 20. Furthermore, air is injected into the coating jig 20 from the air injection ports 21A to 21D. As a result, the seal members 30A to 30D are brought into close contact with the pipe T1 due to the pressure inside the coating jig 20. Therefore, the airtightness between the tube T1 and the first insertion hole 23 can be effectively improved.

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

The gas injector 50 has a gas injection tube 51 for injecting a detection gas into the space between the hood 40 and the outer surface of the tube T1. With the hood 40 covering the tube T1, the open end of the gas injection tube 51 is located at a higher position than the lower end of the hood 40 and at a position that does not contact the outer surface of the tube T1. However, the position of the open end of the gas injection pipe 51 is not limited to this.

<Configuration of pedestal 60 and support roller 61>
A support roller 61 is provided on each of the plurality of pedestals 60. Support rollers 61 support tube T1. The tube T1 supported by the support roller 61 is movable in the X-axis direction by rotation of the support roller 61.

Consider a case where the cylinder 70 moves the rod 71 in the positive direction of the X-axis, and the support roller 61 rotates clockwise with respect to the positive direction of the Y-axis. In this case, due to the frictional force generated between the tube T1 and the support roller 61, the tube T1 can be inserted into the coating jig 20 and the end T2 of the tube T1 can be pressed against the fixed end 11. Further, when the cylinder 70 moves the rod 71 in the negative direction of the X-axis and the support roller 61 rotates counterclockwise with respect to the positive direction of the Y-axis, the friction force generated between the tube T1 and the support roller 61 causes the tube T1 to can be pulled out from the coating jig 20.

The support roller 61 may be movable in the Z-axis direction according to the outer diameter of the tube T1 or the progress of the airtight test. In this case, the mounting surface of the support roller 61 on the pedestal 60 is raised and lowered by a motor (not shown).

<Pulling out mechanism of tube T1>
The airtightness test device 1 may include a drawing mechanism (not shown) for pulling the tube T1 out of the coating jig 20. For example, the pulling mechanism has a clamping part that clamps the pipe T1, and by moving the clamping part in the negative direction of the X axis while the clamping part clamps the pipe T1, the pipe T1 is removed from the coating jig 20. pull it out.

Here, a case will be considered in which the pipe T1 in which the inclined portion T4 is formed is pulled out from the coating jig 20. In this case, even when the force applied to the tube T1 from the seal members 30A to 30D is strong due to the formation of the inclined portion T4, and the force required to pull out the tube T1 is large, the above-mentioned pulling mechanism can be pulled out from the coating jig 20.

In addition, the said pulling-out mechanism may have 10 A of tube fixing parts, the cylinder 70, and the said clamping part. In this case, the clamping portion is provided at the pressing end 11A. The tube T1 is pulled out from the coating jig 20 by the cylinder 70 moving the rod 71 in the negative direction of the X-axis. Thereby, the cylinder 70 applies a pulling force to the tube T1, and the tube T1 can be pulled out from the coating jig 20.

In this embodiment, air is injected into the coating jig 20 from the air inlets 21A to 21D formed in the coating jig 20 that covers the end T2 of the pipe T1, so that the coating jig 20 Internal pressure increases. This makes it difficult for the detection gas used in the airtightness test to flow into the coating jig 20. In other words, it becomes difficult for the detection gas to flow into the tube T1 from the end T2 of the tube T1. Therefore, the accuracy of the airtightness test can be improved.

Further, as described above, a plurality of seal members 30A to 30D that seal between the tube T1 and the first insertion hole 23 are arranged so as to overlap each other in the X-axis direction. Thereby, the airtightness between the tube T1 and the first insertion hole 23 can be improved. Furthermore, by stacking the plurality of sealing members 30A to 30D on top of each other, the strength of the sealing member is made sufficient, while each of the plurality of sealing members 30A to 30D is easily deformed.

Therefore, while making it easier to insert and remove the tube T1 into and from the coating jig 20, it is possible to reduce the sagging of the seal members 30A to 30D when the tube T1 is inserted into and removed from the coating jig 20. Since the sealing members 30A to 30D can be reduced in fatigue, the sealing members 30A to 30D can be used repeatedly.

[Embodiment 2]
Embodiment 2 of the present invention will be described below. For convenience of explanation, members having the same functions as those described in Embodiment 1 will be denoted by the same reference numerals, and the description thereof will not be repeated. FIG. 4 is a perspective view showing the vicinity of the covering jig 20B included in the airtightness testing apparatus 1A according to the second embodiment of the present invention. FIG. 4 omits the tube T1, the vacuum pump 11P, the detection section 12, the front surface 24 of the coating jig 20B, and the hood 40.

As shown in FIG. 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 the inner peripheral surface 26 of the covering jig 20B. The inner peripheral surface 26 is a surface on the back side of the side surface 25. Each of the tubes 22A to 22D is connected to openings A1, A2, A3, and A4 formed in the side surface 25 of the coating jig 20B.

Each of the plurality of covering members 27 covers a corresponding one of the openings A1 to A4 inside the covering jig 20B. Each of the air inlets 21A to 21D is formed between the covering member 27 and the inner peripheral surface 26. As a result, the air inlets 21A to 21D direct the air injected into the coating jig 20B in the direction away from the seal members 30A to 30D after being injected from the air inlets 21A to 21D, or in the direction away from the pipe T1. The coating jig 20B is formed so as to be guided in a direction along the boundaries with the seal members 30A to 30D.

The direction along the boundary between the tube T1 and the seal members 30A to 30D is the circumferential direction D1 of the tube T1. In addition, the direction in which air leaves the seal members 30A to 30D after being injected from the air inlets 21A to 21D passes through the positions of the air inlets 21A to 21D and is perpendicular to the X-axis direction and the tube fixed This is the direction toward the area between the parts 10 and 10.

The direction in which the air injected into the coating jig 20B moves away from the seal members 30A to 30D after being injected from the air injection ports 21A to 21D, or the direction along the boundary between the pipe T1 and the seal members 30A to 30D. guided by. Therefore, air is not guided in a direction that moves the seal members 30A to 30D away from the outer peripheral surface of the tube T1. Therefore, the airtightness between the tube T1 and the first insertion hole 23 can be further improved.

[Modified example]
A plurality of cuts may be formed in each of the second insertion holes 31A to 31D. Thereby, when the tube T1 is inserted into and removed from the coating jig 20, it is possible to further reduce the sagging of the seal members 30A to 30D.

Further, in at least one set of adjacent seal members, each of the plurality of cuts formed in one seal member is shifted from the plurality of cuts formed in the other seal member in the circumferential direction D1 of the pipe T1. You can leave it there. At least one set of adjacent seal members refers to at least one set of the seal members 30A and 30B, the seal members 30B and 30C, or the seal members 30C and 30D. By deviating the cuts, the airtightness between the tube T1 and the first insertion hole 23 can be improved.

〔Example〕
In an example of the present invention, an airtightness test was conducted using the airtightness testing apparatus 1 shown in FIG. 1 under the first test condition and the second test condition. 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 coating jig 20 from the air inlets 21A to 21D, and the average value of the inflow amount of He is from near the center of the pipe T1 to the coating jig 20. This is the average value of the results of three measurements of the amount of He flowing into the interior of the cell. The average value of the inflow amount of He shown in Table 1 is in units of 10 ⁻¹⁰ MPa·m ³ /s.

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

Furthermore, when air is injected under the first test condition, that is, when the pressure inside the coating jig 20 is equal to the air pressure, the average value of the He inflow amount is It became 33,000. Therefore, by injecting air into the coating jig 20, the amount of He flowing into the coating jig 20 could be reduced.

The second test condition is that the diameter of the second insertion holes 31A to 31D of the seal members 30A to 30D in the airtightness testing apparatus 1 is 232 mm, and the outer diameter of the tube T1 is 236 mm. The outer diameter here means the diameter. When no air is injected under the second test condition, that is, when the pressure inside the coating jig 20 is 0 MPa, the He inflow amount was measured three times, and the average value of the He inflow amount was 2165. . In addition, when air is injected under the second test condition, that is, when the pressure inside the coating jig 20 is equal to the air pressure, the average value of the He inflow amount is determined by measuring the He inflow amount three times. It became 113.

Therefore, by reducing the diameters of the second insertion holes 31A to 31D, the amount of He flowing into the coating jig 20 can be further reduced. As described above, by injecting air into the interior of the coating jig 20 and improving the airtightness between the pipe T1 and the first insertion hole 23, the amount of He flowing into the interior of the coating jig 20 is stabilized. can be reduced.

〔summary〕
The airtightness test device according to aspect 1 of the present invention includes a tube fixing portion that fixes the tube at a predetermined position by abutting both ends of the tube and pressing the both ends in the axial direction of the tube; A covering jig for covering an end portion, the covering jig having an air injection port through which air is injected into the inside of the covering jig, and a first insertion hole through which the pipe is inserted. , a plurality of seal members arranged to overlap each other in the axial direction and seal between the tube and the first insertion hole.

In the airtightness test device according to aspect 2 of the present invention, in the above aspect 1, each of the plurality of seal members is formed with a second insertion hole through which the tube is inserted, and the plurality of seal members Each may be configured to be an elastic member that elastically deforms and comes into close contact with the tube when the tube is inserted into the second insertion hole.

In the airtightness test device according to aspect 3 of the present invention, in the above aspect 2, when the second insertion hole is open, the diameter of the second insertion hole is larger than the outer diameter of the pipe at the end. It is also possible to have a small configuration.

In the airtightness test device according to aspect 4 of the present invention, in any one of aspects 1 to 3 above, the air inlet is configured to inject air from the air inlet to be injected into the inside of the coating jig. The covering jig may be configured to be guided in a direction away from the sealing member later, or in a direction along a boundary between the pipe and the sealing member.

The airtightness test device according to aspect 5 of the present invention may be configured to further include a cylinder that presses the tube fixing part against the both ends of the tube in any one of aspects 1 to 4 above.

The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the claims, and embodiments can be obtained by appropriately combining technical means disclosed in different embodiments. are also included within the technical scope of the present invention.

T1 Pipe 1, 1A Airtightness test device 10, 10A Pipe fixing part 20, 20A, 20B Covering jig 21A to 21D Air inlet 23 First insertion hole 30A to 30H Seal member 31A to 31D Second insertion hole 70 Cylinder L1 Diameter L2 Outer diameter T2, T3 end

Claims (5)

a tube fixing part that fixes the tube at a predetermined position by abutting both ends of the tube and pressing the both ends in the axial direction of the tube;
A covering jig for covering an end of the pipe, the covering jig having an air injection port through which air is injected into the inside of the covering jig, and a first insertion hole through which the pipe is inserted. jig and
An airtightness test device comprising: a plurality of seal members arranged to overlap each other in the axial direction and seal between the pipe and the first insertion hole. A second insertion hole through which the tube is inserted is formed in each of the plurality of seal members,
The airtight test according to claim 1, wherein each of the plurality of sealing members is an elastic member that elastically deforms and comes into close contact with the tube when the tube is inserted into the second insertion hole. Device. 3. The airtightness testing device according to claim 2, wherein the second insertion hole has a diameter smaller than an outer diameter of the tube at the end when the second insertion hole is open. The air inlet directs the air injected into the coating 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. The airtightness test device according to any one of claims 1 to 3, wherein the covering jig is formed so as to be guided in a direction. The airtightness test device according to any one of claims 1 to 3, further comprising a cylinder that presses the tube fixing part against the both ends of the tube.

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