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 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. DETAILED DESCRIPTION OF THE INVENTION

[0008] <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 30, 30A. The airtightness testing apparatus 1 also includes a hood 40, a gas injector 50, a base 60, a support roller 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. An insertion hole 23 is formed in the front surface 24, through which the pipe T1 is inserted.

[0026] <Configuration of Seal Members 30, 30A> Fig. 3 is a diagram showing the configuration of the seal member 30 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 seal member 30, and the diagram indicated by reference numeral 102 in Fig. 3 is a cross-sectional view showing the cross-sectional configuration of the seal member 30 taken along dotted line L1 of reference numeral 101 in Fig. 3. The diagram indicated by reference numeral 102 in Fig. 3 also shows other members located near the seal member 30 in the airtightness testing apparatus 1.

[0027] The sealing member 30A provided in the covering jig 20A has the same configuration as the sealing member 30. Therefore, in the following description, only the sealing member 30 will be described, and a description of the sealing member 30A will be omitted.

[0028] 1 and 2, the seal member 30 is provided in the insertion hole 23 and seals the gap between the pipe T1 and the insertion hole 23. As indicated by reference numeral 101 in FIG. 3, the seal member 30 has an annular shape that allows the pipe T1 to be inserted therethrough. As indicated by reference numeral 102 in FIG. 3, the seal member 30 includes a fixed portion 31 and an expandable portion 32.

[0029] The fixed portion 31 is a portion that maintains a substantially constant shape regardless of the pressure inside the seal member 30. The fixed portion 31 may be made of, for example, stainless steel, but is not limited to this material. The fixed portion 31 is located on the outer periphery of the seal member 30. In a cross section perpendicular to the circumferential direction of the seal member 30, the fixed portion 31 has a substantially U-shape that is convex toward the outer periphery of the seal member 30.

[0030] The stretchable portion 32 is a portion that stretches and contracts in response to the pressure inside the seal member 30. The stretchable portion 32 is made of rubber such as NBR (acrylonitrile butadiene rubber), but is not limited to this and may be made of a resin material such as silicone. The stretchable portion 32 is located on the inner circumferential side of the seal member 30. In a cross section perpendicular to the circumferential direction of the seal member 30, the stretchable portion 32 has a generally U-shape that convex toward the inner circumferential side of the seal member 30.

[0031] The seal member 30 is formed with an air passage port 33 through which air passes between the inside and outside of the seal member 30. The seal member 30 expands and contracts in the radial direction of the tube T1 as the pressure inside the seal member 30 is controlled by the air passing through the air passage port 33. Specifically, air passes from the outside to the inside of the seal member 30 through the air passage port 33, i.e., air is injected into the inside of the seal member 30 through the air passage port 33, thereby increasing the pressure inside the seal member 30. Furthermore, air passes from the inside to the outside of the seal member 30 through the air passage port 33, i.e., air is sucked from the inside of the seal member 30 through the air passage port 33, thereby decreasing the pressure inside the seal member 30.

[0032] When the pressure inside the seal member 30 increases, the seal member 30 expands toward the inside of the annular shape, and the gap between the insertion hole 23 and the pipe T1 is sealed by the seal member 30. As a result, it is possible to prevent the detection gas from flowing into the inside of the covering jig 20 from near the center of the pipe T1 and to prevent the detection gas from flowing into the inside of the pipe T1 from the end T2 of the pipe T1. This improves the accuracy of the airtightness test.

[0033] Furthermore, when the seal member 30 is expanded toward the inside of the annular shape, it is possible to prevent air inside the covering jig 20 from leaking out to the outside. That is, it is possible to prevent the detection gas near the covering jig 20 from being blown away by air leaking from inside the covering jig 20. Therefore, the vicinity of the covering jig 20 can also be included in the test range of the pipe T1. Therefore, the untested range of the pipe T1 in the airtightness test using the airtightness test device 1 can be reduced.

[0034] On the other hand, when the pressure inside the seal member 30 decreases, the seal member 30 contracts toward the outside of its annular shape, thereby reducing the pressure from the seal member 30 to the pipe T1. In this state, the frictional force between the seal member 30 and the pipe T1 is smaller than when the seal member 30 expands toward the inside of its annular shape, or the seal member 30 and the pipe T1 are not in contact with each other. This reduces the force required to insert or remove the pipe T1 from the covering jig 20. This makes it easier to remove the pipe T1 from the airtightness testing apparatus 1. Furthermore, wear of the seal member 30 caused by friction between the seal member 30 and the pipe T1 can be reduced.

[0035] 3, a plurality of air passage holes 33 may be formed along the circumferential direction of the seal member 30. This allows the seal member 30 to expand and contract evenly compared to when there is only one air passage hole 33, even if the stretchable portion 32 is made of thick rubber.

[0036] In the example shown by reference numeral 101 in Fig. 3, eight air passage ports 33 are formed at equal intervals along the circumferential direction of the seal member 30. However, the number and intervals of the air passage ports 33 are not limited to the example shown by reference numeral 101 in Fig. 3. The greater the number of air passage ports 33, the more evenly the seal member 30 can expand and contract.

[0037] Moreover, the air passage opening 33 is formed on the radially outer side of the seal member 30. That is, the air passage opening 33 is formed in the fixed part 31. Therefore, even if the expansion / contraction part 32 expands and contracts due to a change in the pressure inside the seal member 30, the air can stably pass through the air passage opening 33.

[0038] The sealing member 30 is disposed inside the covering jig 20. As described above, air is injected into the covering jig 20 through the air injection ports 21A to 21D.

[0039] For this reason, the force with which the air presses the seal member 30 from inside the covering jig 20 is usually greater than the force with which the detection gas presses the seal member 30 from near the center of the tube T1. Therefore, the force acting toward the covering jig 20 is greater than the force acting in the direction separating the seal member 30 from the covering jig 20 when the seal member 30 is disposed inside the covering jig 20. This makes it possible to further improve the airtightness between the tube T1 and the insertion hole 23.

[0040] The airtightness testing device 1 further includes an air control mechanism (not shown). The air control mechanism can separately control the timing at which air is passed through the air passage port 33 and the timing at which air is injected into the covering jig 20.

[0041] The air passing through the air passage port 33 is used to expand and contract the seal member 30. On the other hand, the air injected into the covering jig 20 is used to increase the pressure inside the covering jig 20. Therefore, the purpose of using the air passing through the air passage port 33 is different from the purpose of using the air injected into the covering jig 20. By separately controlling the timing of passing the air through the air passage port 33 and the timing of injecting air into the covering jig 20 using an air control mechanism, the workability of the airtightness test can be improved.

[0042] 1, the airtightness test apparatus 1 includes only one seal member 30. However, the airtightness test apparatus 1 may include multiple seal members 30. In this case, the multiple seal members 30 may be arranged along the axial direction of the pipe T1. This more reliably prevents the detection gas from flowing into the covering jig 20 from near the center of the pipe T1 and prevents air inside the covering jig 20 from leaking out of the covering jig 20 when the seal member 30 is in an expanded state.

[0043] <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.

[0044] 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.

[0045] <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.

[0046] 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.

[0047] 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).

[0048] 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.

[0049] 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]

[0050] 1. Airtightness testing equipment 10, 10A pipe fixing part 20, 20A coating jig 21A~21D Air inlet 23 Insertion hole 30, 30A sealing material 33 Air passage 70 cylinders 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, an air inlet through which air is injected into the covering jig is formed in the covering jig; an insertion hole through which the pipe is inserted is formed in the covering jig; The valve further includes an annular seal member that seals between the pipe and the insertion hole and through which the pipe can be inserted, The sealing member has an air passage opening formed therein through which air passes between the inside and the outside of the sealing member, the sealing member expands and contracts in a radial direction of the pipe as the pressure inside the sealing member is controlled by the air passing through the air passage port; The sealing member is a fixing portion that maintains a constant shape regardless of the pressure inside the sealing member; an expansion / contraction portion that expands and contracts in response to pressure inside the sealing member; An airtightness testing device comprising:

2. 2. The airtightness testing device according to claim 1, wherein a plurality of the air passage openings are formed along the circumferential direction of the sealing member.

3. 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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