Gas leak repair methods

Abstract

To reduce a repair work of gas leakage.SOLUTION: A gas leakage repair method for repairing a plurality of gas leakage locations in which gas passages are continuous to each other, comprises a step of suctioning gas (G) leaked from any of gas leakage locations (S1, S2) to make at least some of the plurality of gas leakage locations (S1, S2) negative pressure, and a step of applying negative pressure to at least some of the plurality of gas leakage locations (S1, S2), and then plugging the negative-pressure gas leakage locations (S1, S2) with a repair material (4).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a gas leakage repair method for repairing a gas leak location when a gas leak occurs from gas-insulated equipment. [Background technology]

[0002] As gas-insulated equipment deteriorates over time, pinholes may form in the flanges, the sealing performance of the flange packing may deteriorate, and cracks may form in the welds, which may cause the insulating gas inside the gas-insulated equipment to leak to the outside.If a gas leak is left unattended, the insulating gas inside the gas-insulated equipment will be lost, the insulating performance will deteriorate, and the equipment may stop functioning, so it is necessary to repair the gas leak as soon as possible. For example, a method has been disclosed in which a repair material (hardening resin) is buried on the surface of a damaged section of a pipe (gas leak location) and the repair material is hardened to cover the damaged section and repair the gas leak location (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-121878 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in cases where there are multiple interconnected gas leak points (the mating surfaces of the flanges, the gaps between the flanges and the connecting members), such as in the case of gaskets on flanges, the gas discharge pressure from the remaining gas leak points increases as the gas leak points are filled in turn, making it difficult to fill them with repair material. Furthermore, when there are a large number of gas leaks in gas-insulated equipment, it is necessary to fill each gas leak with repair material, which makes the repair work time-consuming.

[0005] Therefore, the present invention has been made in consideration of the above-mentioned problems, and provides a technique that can reduce the work required to repair gas leaks. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, an aspect of the present invention is a gas leak repair method for repairing multiple gas leak locations where gas paths are connected to each other, characterized by having the steps of: sucking gas leaking from any of the gas leak locations to create negative pressure in at least some of the multiple gas leak locations; and, after creating negative pressure in at least some of the multiple gas leak locations, sealing the gas leak location that has become negative pressure with a repair material.

[0007] The method also includes a step of pressing one end of the pipe material against the object to be repaired so as to surround the gas leak location to be sucked in, and in the step of creating a negative pressure in the gas leak location, the step of sucking in the gas that has leaked into the pipe material to create a negative pressure inside the pipe material, and after creating a negative pressure inside the pipe material, the step of covering and fixing one end of the pipe material with the object to be repaired using a hardening repair material, and in the step of sealing the gas leak location that has become negative pressure with the repair material, it is preferable that the gas leak location that has become negative pressure other than the gas leak location surrounded by the pipe material is sealed with the hardening repair material, and then the gas leak location surrounded by the pipe material is sealed with the hardening repair material.

[0008] It is also preferable to have a step of temporarily fixing one end of the pipe material to the object to be repaired using an ultraviolet-curing repair material before creating a negative pressure inside the pipe material.

[0009] In addition, in the process of temporarily fixing one end of the pipe material to the object to be repaired, it is preferable that a portion of the periphery of the one end of the pipe material is temporarily fixed to the object to be repaired using the ultraviolet-curing repair material.

[0010] Furthermore, when sealing the gas leak site surrounded by the pipe material with a curing repair material, it is preferable to form the pipe material from a transparent material, inject an ultraviolet-curing repair material into the inside of the pipe material, and irradiate ultraviolet light from the outside of the pipe material to harden the ultraviolet-curing repair material inside the pipe material.

[0011] Furthermore, when sealing the gas leak site surrounded by the pipe material with a hardening type repair material, it is preferable to inject the hardening type repair material at a pressure equal to or greater than the discharge pressure of the gas leak, and fill the gas leak site in the object to be repaired that is the cause of the gas leak with the hardening type repair material.

[0012] It is also preferable that one end of the tubular member is formed so that the inner wall approaches the outer wall as it approaches the tip.

[0013] It is also preferable that the method includes the steps of cutting the pipe material to shorten it after sealing the gas leak location surrounded by the pipe material with a hardening repair material, and covering the cut pipe material with a hardening repair material and hardening it.

[0014] It is also preferable to have a step of covering the entire hardened repair material with another hardening repair material and hardening it after the step of covering the cut pipe material with a hardening repair material and hardening it.

[0015] It is also preferable to have a step of applying a coating to protect the exposed repair material after the step of covering the entire hardened repair material with a hardening type repair material and hardening it. [Effects of the Invention]

[0016] According to the aspects of the present invention, it is possible to reduce the amount of work required to repair gas leaks. [Brief explanation of the drawings]

[0017] [Figure 1](a) is an oblique view of the connection point of the flange part where the sealing performance of the packing of the gas-insulated equipment that is the target of the gas leak repair method has deteriorated, (b) is a cross-sectional view along AA in (a), and (c) is a cross-sectional view along BB in (a). [Figure 2] 10A and 10B are diagrams illustrating a method for temporarily fixing a pipe material to a flange portion. [Figure 3] 10A and 10B are diagrams illustrating a method of fixing a pipe to a flange portion by creating a negative pressure inside the pipe. [Figure 4] 10A and 10B are diagrams illustrating a method of injecting repair material into the inside of a pipe material. [Figure 5] 10A and 10B are diagrams illustrating a method for hardening a repair material injected into the inside of a pipe material. [Figure 6] 10A and 10B are diagrams illustrating a method of filling a pipe material with repair material after cutting the pipe material. [Figure 7] 10A and 10B are diagrams illustrating a method of filling a pipe material with repair material and then filling the pipe material with more repair material. [Figure 8] 10A to 10C are diagrams illustrating a method for forming a protective layer that protects the repair material. [Figure 9] 1 is a cross-sectional view of a cementing portion of a bushing of a gas-insulated device that is the target of a gas leakage repair method. [Figure 10] 1 is a perspective view of a welded portion where a pinhole has occurred in a gas-insulated device that is the target of a gas leakage repair method. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Preferred embodiments of the present invention will be described with reference to the drawings. Note that the embodiments shown below are merely examples, and various other embodiments are possible within the scope of the present invention.

[0019] The gas leak repair method is used, for example, to repair gas leaks from flange joints in gas-insulated equipment installed in power plants and substations, around connecting members (e.g., bolts and nuts) that connect flanges together, around cementing of bushings, and from damaged areas such as cracks and pinholes that have occurred in flanges. In other words, the gas leak repair method is suitable for repairing multiple gas leak locations where gas paths are connected to each other. Below, we will explain a gas leak repair method for when the packing (sealing member) provided on the mating surface of the flanges at the joints of the flanges of gas-insulated equipment has been damaged due to deterioration or the like, causing gas to leak from the outer periphery of the flanges or from gaps between the connecting members and the flanges (e.g., bolt holes).

[0020] Figure 1(a) is a perspective view of the connection point of the flange portion where the sealing performance of the packing has deteriorated, Figure 1(b) is a cross-sectional view taken along line AA in Figure 1(a), and Figure 1(c) is a cross-sectional view taken along line BB in Figure 1(a). As shown in FIG. 1 , at the joint between flanges 1, a packing (sealing member) 20 is provided on the mating surfaces of the flanges 1 to prevent gas from leaking from the gas-insulated equipment to the outside. If cracks develop in the packing 20 due to aging or other reasons, its sealing function deteriorates, allowing gas to leak to the outside through the cracks. Therefore, it is necessary to repair the gas leak points on the outside of the packing 20 to stop the gas leak. Gas leaks from the packing 20 can be easily detected using a gas leak detector or by applying soapy water. Specifically, gas G leaking from the packing 20 is discharged to the outside of the flanges 1 through a gap S1 (see FIG. 1( b)) between the mating surfaces of the flanges 1 and a gap S2 (see FIG. 1( c)) between the flanges 1 and the connecting member 30 (bolt 31, nut 32). In other words, the gaps S1 and S2 are the gas leakage points for gas G leaking from the packing 20 of the flanges 1. In the following, an example will be described in which leaked gas is sucked through the gap S1 when repairing a gas leak.

[0021] When repairing a gas leak from the packing 20 in the flange portion 1, the periphery of the gap S1 where the gas is leaking (the outer peripheral surface of the flange portion 1) is first scraped, and then, as shown in FIG. 2, one end of the pipe material 3 is pressed against the outer peripheral surface of the flange portion 1 so as to surround a portion of the gap S1. The pipe material 3 is preferably, for example, a colorless and transparent acrylic pipe formed in a cylindrical shape. The reason for making the pipe material colorless and transparent is that it allows ultraviolet light to pass through and harden the ultraviolet-curing repair material injected into the pipe material 3. Note that the pipe material 3 is not necessarily limited to a colorless and transparent acrylic pipe, as long as it is capable of transmitting ultraviolet light.

[0022] One end of the pipe 3 is formed so that the inner wall approaches the outer wall as it approaches the tip. Specifically, the inner diameter of one end of the pipe 3 is expanded so that the inner wall slopes toward the outer wall as it approaches the tip. This is because when the repair material injected into the inside of the pipe 3 hardens, the repair material in the expanded diameter portion 3a functions as a stopper, preventing the hardened repair material from slipping out to the other end of the pipe 3. The height of the expanded diameter portion 3a is formed to be approximately 3 mm to 5 mm.

[0023] One end of the pipe material 3 is butted against the outer peripheral surface of the flange portion 1 so as to surround part of the gap S1 on the mating surface of the flange portion 1, and then an ultraviolet-curing repair material 4 (hereinafter referred to as UV repair material 4) is applied around one end of the pipe material 3 to fill the boundary (gap) between one end of the pipe material 3 and the outer peripheral surface of the flange portion 1. At this time, the entire periphery of one end of the pipe material 3 is not filled with the UV repair material 4, but only a portion of the periphery of one end of the pipe material 3 is filled with the UV repair material 4. This is because if one tries to fill the entire periphery of one end of the pipe material 3 from the beginning, the discharge pressure of the gas G from the boundary between the one end of the pipe material 3 and the outer peripheral surface of the flange portion 1 will gradually increase as the gas leak area becomes smaller, making it difficult to fill with the UV repair material 4. Furthermore, when filling one end of the pipe material 3 with UV repair material 4, it is preferable to keep it at a height of approximately 3 mm to 5 mm from the surface of the flange portion 1 so that the ultraviolet rays that will be irradiated later can reliably reach the UV repair material 7 (described later) inside the pipe material 3.

[0024] The UV repair material 4 may be, for example, a one-component ultraviolet-curing acrylic, but is not limited to this repair material as long as it is a material that hardens when exposed to ultraviolet light. The repair material is not limited to the UV repair material 4, and a two-component curing repair material (for example, two-component epoxy resin) may also be used. Then, the UV repair material 4 is immediately irradiated with ultraviolet light using an ultraviolet irradiator to harden it. The ultraviolet irradiator used is one that irradiates ultraviolet light with a wavelength of 365 nm or 405 nm, for example. The UV repair material 4 is a translucent liquid before hardening and becomes a white solid after hardening, allowing visual confirmation of whether it has hardened or not. The UV repair material 4 hardens immediately, and as a result of the hardening of the UV repair material 4, the pipe material 3 is erected on the outer peripheral surface of the flange portion 1. Therefore, at this stage, one end of the pipe material 3 is temporarily fixed to the outer peripheral surface of the flange portion 1. In this state, gas G leaking from the packing 20 leaks out from the other end of the pipe material 3, a portion of the boundary between the one end of the pipe material 3 and the outer peripheral surface of the flange portion 1, and gaps S1 and S2 that are not surrounded by the pipe material 3.

[0025] Next, as shown in FIG. 3 , a vacuum pump 6 is connected to the other end of the pipe 3 via a tube 5, and gas G leaked into the inside of the pipe 3 is sucked in, thereby creating a negative pressure inside the pipe 3, a gap S1 at the mating surface of the flange 1, and a gap S2 between the flange 1 and the connecting member 30 (bolt 31, nut 32). That is, by sucking gas G with the vacuum pump 6, a negative pressure is created in the space formed outside the packing 20 in the flange 1. Specifically, the vacuum pump 6 can create a negative pressure inside the pipe 3 and in the gaps S1 and S2 by sucking in an amount of gas greater than the amount of gas leaking from the packing 20. As a result, gas G leaking from the packing 20 does not leak out from the boundary between the flange 1 and one end of the pipe 3 or the gaps S1 and S2, but is all collected inside the pipe 3 and sucked in by the vacuum pump 6. The vacuum pump 6 does not need to create a negative pressure inside the pipe 3 close to a vacuum, in order to prevent the pipe 3 from being damaged or the UV repair material 4 from being sucked in together with the gas G. The extent to which the negative pressure should be created can be adjusted as appropriate depending on the size of the flange 1, the diameter of the bolt 31, and the discharge pressure of the gas G.

[0026] After creating a negative pressure inside the tubular member 3 with a vacuum pump 6, the UV repair material 4 is used to fill the remaining area around one end of the tubular member 3 that has not been filled with the UV repair material 4, and an ultraviolet irradiator is used to irradiate the UV repair material 4 with ultraviolet light and harden it. As a result, the entire area around one end of the tubular member 3 is filled with the UV repair material 4, and the one end of the tubular member 3 is completely fixed to the flange portion 1. Therefore, the boundary between the flange portion 1 and the one end of the tubular member 3 is completely sealed with the UV repair material 4, so that gas G leaking from the gap S1 surrounded by the tubular member 3 does not leak out from inside the tubular member 3. Furthermore, when filling the remaining area with the UV repair material 4, the UV repair material 4 can be sucked toward the one end of the tubular member 3 by the negative pressure, so the periphery of the tubular member 3 can be completely filled without any gaps.

[0027] After the pipe member 3 is fixed to the flange portion 1, the gaps S1 and S2 not surrounded by the pipe member 3 are filled with the UV repair material 4, and the UV repair material 4 is irradiated with ultraviolet light using an ultraviolet irradiator to harden. This seals the negative pressure areas of the gaps S1 and S2 not surrounded by the pipe member 3. The repair material is not limited to the UV repair material 4, but a two-component curing repair material (e.g., two-component epoxy resin) may also be used. If the vacuum pump 6 does not create a negative pressure in all areas of the gaps S1 and S2, only the negative pressure gas leak areas can be filled with the repair material. For the remaining gas leak areas that could not be created a negative pressure, the pipe member 3 can be placed in the gap S1 again and suctioned with the vacuum pump 6, performing the same repair as above. That is, the gas leaking from one of the gas leak areas can be sucked out, creating a negative pressure in at least some of the multiple gas leak areas, and the negative pressure gas leak areas can then be sealed with the repair material.

[0028] 4, an ultraviolet-curing repair material 7 (hereinafter referred to as UV repair material 7) is injected and filled into the inside of the tubular material 3. Specifically, the tube 5 and vacuum pump 6 attached to the other end of the tubular material 3 are removed, and a syringe 9 is connected to the other end of the tubular material 3 via a tube 8.

[0029] After connecting the syringe 9, the UV repair material 7 is injected from the syringe 9 into the interior of the tubing 3. By injecting the UV repair material 7 at a pressure equal to or greater than the discharge pressure of the leaking gas G, the UV repair material 7 penetrates into the gap S1 that is causing the gas leak. After the UV repair material 7 is completely injected, as shown in Figure 5, while maintaining the pressure of the UV repair material 7 from the syringe 9, ultraviolet light is irradiated from the outside of the tubing 3 onto the UV repair material 7 inside the tubing 3 using an ultraviolet irradiator L to harden the UV repair material 7. At this time, the ultraviolet light is irradiated only onto the UV repair material 7 inside the tubing 3. Because the tubing 3 is made of a colorless, transparent acrylic tube, the ultraviolet light passes through the tubing 3 and hits the UV repair material 7. As a result, the UV repair material 7 inside the tubing 3 and in the gap S1 hardens, sealing the gap S1 surrounded by the tubing 3.

[0030] The UV repair material 7 fills not only the inside of the pipe 3 but also the gap S1, eliminating gas accumulation and maximizing the contact area of ​​the UV repair material 7. Furthermore, the UV repair material 7 inside the pipe 3 and the UV repair material 7 inside the gap S1 are integrated, enabling a stronger repair. The UV repair material 7 in the expanded diameter section 3a of the pipe 3 functions as a stopper (plug) that stops the UV repair material 7 from moving toward the other end of the pipe 3 due to the discharge pressure of the gas attempting to leak out, thereby improving the gas leakage prevention function.

[0031] The UV repair material 7 may be, like the UV repair material 4, a one-component, ultraviolet-curing acrylic, for example; however, the repair material is not limited to this, as long as it is a material that hardens when exposed to ultraviolet light. Furthermore, the repair material injected into the interior of the tubular member 3 is not limited to the UV repair material 7; a two-component curing repair material (such as a two-component epoxy resin) may also be used. However, when using a two-component repair material, since it does not harden immediately, it is necessary to continue applying pressure to the repair material with the syringe 9 until it hardens so that the repair material is not pushed back by the gas pressure. In this case, the tubular member 3 does not need to be made of a colorless, transparent material that transmits ultraviolet light.

[0032] After the UV repair material 7 inside the tubing 3 has hardened, the tube 8 and syringe 9 are removed, and the tubing 3 is cut to shorten it, leaving only one end of the tubing 3. When cutting the tubing 3, an ultrasonic cutter is used, which allows the tubing 3 to be cut without placing excessive stress on the hardened UV repair material 7. After cutting the tubing 3, a portion of the tubing 3 is exposed from the UV repair material 4.

[0033] Next, as shown in Figure 6, the part of the pipe material 3 exposed from the UV repair material 4 is filled with an ultraviolet-curing repair material 10 (hereinafter referred to as UV repair material 10), and the UV repair material 10 is irradiated with ultraviolet light using an ultraviolet irradiator L to harden. As a result, the pipe material 3 is completely covered with the UV repair materials 4, 10. The UV repair material 10 may be the same material as the UV repair materials 4, 7, or a two-component hardening repair material (such as a two-component epoxy resin) may be used instead of the UV repair material 10.

[0034] Next, as shown in FIG. 7, the UV repair materials 4, 10 covering the pipe 3 are completely filled with an ultraviolet-curing repair material 11 (hereinafter referred to as UV repair material 11), and the UV repair material 11 is irradiated with ultraviolet light using an ultraviolet irradiator L to harden. This further reinforces the pipe 3 with the UV repair material 11. The UV repair material 11 is filled so as to completely cover the entire UV repair material 4, 10, ensuring a radius of at least 20 mm from the gap S1. This allows for a final surface finish of the repaired area, while also ensuring sufficient wall thickness and contact area for increased strength. The UV repair material 11 may be the same material as the UV repair materials 4, 7, and 10, or a two-component curing repair material (e.g., two-component epoxy resin) may be used instead of the UV repair material 11.

[0035] Next, as shown in FIG. 8, a coating is applied to protect the UV repair material 11 exposed to the outside. Specifically, in consideration of long-term weather resistance, protective coating is applied in multiple steps to block UV rays, forming protective layers 12 and 13. The reason for applying the protective coating in multiple steps is to minimize the impact on the UV repair material 11 by applying a thin layer of protective coating and allowing it to dry quickly. The number of protective layers 12 and 13 is not limited to two, and more than two layers may be formed. Furthermore, each protective layer 12 and 13 may be formed of the same material or different materials.

[0036] According to the gas leak repair method described above, by creating a negative pressure in the gaps S1 and S2, which are gas leak points from the packing 20 of the flange portion 1, the gas G leaking into the space formed outside the packing 20 of the flange portion 1 can be concentrated at the suction point (vacuum pump 6). This allows the gas G leaking over a wide area to be concentrated and repaired while preventing gas leakage from other areas, eliminating the need to fill each gas leak point with repair material and reducing the amount of work required to repair the gas leak. Furthermore, since the gas leak repair procedure involves sealing the points where the gas G was sucked and concentrated last, the majority of the gas leak points can be repaired under a negative pressure, reducing the amount of work required to repair the gas leak points. Furthermore, by butting one end of the pipe material 3 against the object to be repaired, such as the flange portion 1, so as to surround the gaps S1 and S2 where the gas leaks are located, and sucking in the gas G that has leaked into the pipe material 3 and creating a negative pressure in the pipe material 3, it is possible to create a negative pressure in gas leak areas near the gas leak area where the pipe material 3 is butted. Therefore, even if the gas leaks are spread over a wide area, there is no problem, as in the past, where as the gas leak areas are covered one by one, the discharge pressure of the gas G from the remaining gas leak areas increases, making it difficult to cover them with repair material, and the gas leak areas that are under negative pressure can be easily filled with repair material. Furthermore, by using the pipe material 3, the leaked gas G can be easily concentrated. Therefore, the repair work for the gas leaking part can be reduced and can be completed in a short time, so that the amount of gas leakage can be reduced and the gas replenishment time for making up for the leaked gas G can be shortened.

[0037] <Other> While the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and includes all aspects encompassed by the concept of the present invention and the scope of the claims. Furthermore, each configuration may be appropriately and selectively combined to achieve at least some of the above-described problems and effects. For example, in the above-mentioned gas leak repair method, the location where the pipe material 3 is erected and the leaked gas G is sucked in is not limited to the gap S1 between the mating surfaces of the flange portion 1, but may also be the gap S2 between the flange portion 1 and the connecting member 30 (bolt 31, nut 32), as shown in Figure 1(c). In addition, the method is not limited to fixing the pipe material 3 so as to surround a portion of the gaps S1 and S2 and sucking out the gas G inside the pipe material 3 to create a negative pressure in the gaps S1 and S2. It is also possible to bring a vacuum pump or the like close to the gaps S1 and S2 and suck out the leaking gas G to create a negative pressure in the gaps S1 and S2.

[0038] The gas leak repair method can also be applied to repairing gas leaks from cemented portions of bushings in gas-insulated equipment, for example, as shown in Fig. 9. Specifically, the bushing has a metal tank 91 and a ceramic porcelain bushing 92 sealed with a gasket 93, and the tank 91 and the porcelain bushing 92 are joined by a cemented portion 94 outside the gasket 93. In such a structure, if the gasket 93 is damaged due to deterioration over time or the like, the gas G inside the tank 91 will leak from the gasket 93, and may further leak from the cementing portion 94 made of a porous material or the gap S3 between the tank 91 and the connecting member 95. In such a case, by sucking the gas G from the cementing portion 94 and creating a negative pressure, the gas G leaking into the space formed outside the gasket 93 can be collected at the suction point (vacuum pump 6), and structurally, the gas G leaking over a wide area can be repaired in a collected state, thereby reducing the work required to repair the gas leak.

[0039] The gas leak repair method can also be applied to repairing a welded joint 17 between a flange 15 and a pipe 16 in gas-insulated equipment, where pinholes 14a, 14b, and 14c have occurred, as shown in Figure 10. In this case, by creating a negative pressure around pinhole 14a (encircled by a dashed line), gas does not leak from pinholes 14b and 14c located near pinhole 14a, and pinholes 14b and 14c can be easily filled with a repair material. This eliminates the need to perform repair work while resisting the gas discharge pressure at each of pinholes 14a, 14b, and 14c, as in the conventional method, thereby reducing the amount of work required to repair gas leaks. [Explanation of symbols]

[0040] 1 Flange 3 Tube material 3a Expanded diameter part 4 UV repair material 5 tubes 6. Vacuum pump 7 UV repair material 8 tubes 9 syringes 10 UV repair material 11 UV repair material 12 Protective layer 13 Protective layer 14a, 14b, 14c Pinhole 15 Flange 16 Piping 17 Welded parts 20 Packing (sealing material) 30 Connecting member 31 volts 32 Nut G Gas L UV irradiator S1, S2, S3 gaps (gas leak locations)

Claims

1. A gas leak repair method for repairing a plurality of gas leak locations where gas passages are connected to each other at a connection portion between flange portions, comprising: a) a step of abutting one end of a pipe material against the flange portion so as to surround any one of the gas leak locations of the entire flange portion; a) a step of sucking gas leaked into the inside of the tubular material to create a negative pressure inside the tubular material; c) A process of creating a negative pressure in the outer space of the packing on the mating surfaces of the flange portions, and repairing gas leak points that are not surrounded by the pipe material with a hardening type repair material in an environment where gas leak points of the entire flange portion are concentrated in the pipe material; d) after step c), a step of injecting a hardening type repair material into the gas leak location surrounded by the pipe material to seal the gas leak location; A gas leak repair method comprising the steps of:

2. A gas leak repair method as described in claim 1, characterized in that it includes a step (e) between step (i) and step (iii) of creating a negative pressure inside the pipe material, and then using a hardening type repair material to cover and fix one end of the pipe material with the hardening type repair material.

3. A gas leak repair method according to claim 1 or 2, characterized in that it further comprises a step of performing steps a) to d) on a gas leak location that is not under negative pressure if such location is found to be leaking.

4. 4. A gas leak repair method according to claim 1, wherein in step d), the hardening type repair material is injected at a pressure equal to or greater than the discharge pressure of the gas leak.

5. 5. A gas leak repair method according to claim 1, wherein in step (a), one end of the pipe material is abutted against a gap between mating surfaces of the flange portion.

6. A gas leak repair method according to any one of claims 1 to 4, characterized in that in step (a), one end of the pipe material is abutted against the gap between the flange portions and a connecting member that connects the flange portions together.

7. A gas leak repair method as described in any one of claims 1 to 6, characterized in that it includes a step of temporarily fixing one end of the pipe material to the flange portion using a hardening repair material before creating a negative pressure inside the pipe material.

8. In the step of temporarily fixing one end of the pipe material to the flange portion, 8. The gas leak repair method according to claim 7, wherein a portion of the periphery of one end of the pipe material is temporarily fixed to the flange portion using the hardening type repair material.

9. In the step (d), the pipe material is formed from a transparent material, and an ultraviolet curing repair material is injected into the inside of the pipe material; 9. The gas leak repair method according to claim 1, wherein ultraviolet light is irradiated from the outside of the pipe material to harden the ultraviolet-hardening repair material inside the pipe material.

10. 10. The gas leak repair method according to claim 1, wherein one end of the pipe material is formed so that the inner wall approaches the outer wall as it approaches the tip.

11. After the step D), cutting the tubing to shorten it; a step of covering the cut pipe material with a hardening type repair material and hardening the repair material; 11. The gas leak repair method according to claim 1, further comprising:

12. After the step of covering the cut pipe material with a hardening repair material and hardening it, 12. The gas leak repair method according to claim 11, further comprising the step of covering the entire hardened repair material with a hardening type repair material and hardening it.

13. After the process of covering the entire hardened repair material with another hardening type repair material and hardening it, 13. The gas leak repair method according to claim 12, further comprising a step of applying a coating to protect the exposed repair material.

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