JP4027065B2 - Pipeline repair method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of repairing a pipeline that repairs a bifurcation in a pipeline such as a gas pipe or a water pipe. To the law Related.
[0002]
[Prior art]
In general, when repairing defects such as corrosion in pipelines such as gas pipes and water pipes, a repair band is covered on the outer periphery of the repaired part, in addition to repair methods such as welding overlay, so-called crackling. The method is adopted. However, welding overlays and crackling are effective as a first aid, but are not suitable for permanent repairs. On the other hand, the method of covering the outer periphery of the pipeline with a repair band is an extremely effective means when the object to be repaired is a straight pipe, but a repair band may be put on to repair the bifurcation. It is not possible to adopt it.
[0003]
For this reason, when repairing a bifurcation part permanently, the pipeline in the vicinity including the bifurcation part is cut and removed by a predetermined length, a new pipe is inserted into the removed part, and this pipe is installed in the existing pipeline. In general, repair methods for welding to steel have been performed. When performing this repair, it was necessary to excavate a work mine around the repair site in order to secure a work space. Moreover, when performing repair, the fluid which stops inside was provided with the bypass line which stops a fluid temporarily and avoids a repair part so that the fluid which flows through inside may not be discharge | released to air | atmosphere.
[0004]
[Problems to be solved by the invention]
However, in order to secure the work space, drilling a work mine around the repaired part takes time and effort, not only reducing the efficiency of repair, but also improving the cost of repair Will be invited.
[0005]
In addition, when temporarily stopping the fluid flowing inside the gas and tap water, considering the effect on the surrounding dwelling, it is necessary to perform repair work at midnight when the demand for gas and tap water is low, The time required for the work was also limited. To stop gas and tap water, it is necessary to close valves at several stations installed around the repair site, and this work is also expensive.
[0006]
On the other hand, if a bypass line is provided in order to suppress the influence by the stop of gas and tap water as much as possible, the cost will be generated and the time required for work will also be required. For example, when repairing a branch part formed in the governor installation part of a gas pipe, a bypass line is provided from a plug part provided slightly upstream from the branch part. It was necessary to excavate up to the part, leading to cost increase and prolonged work time.
[0007]
Therefore, in the present invention, when repairing the branch portion, the pipeline branch portion is repaired efficiently and at a low cost without stopping the fluid flowing through the pipeline and without separately installing a bypass line. How to repair a pipeline The law provide.
[0008]
[Means for Solving the Problems]
In the present invention, in order to solve the above-described problem, a repair method for a pipeline in which a repair band is covered and repaired at a branch portion extending from one pipeline to another pipeline, and the repair band is arranged in a circumferential direction. It is composed of a band piece divided into at least two parts, and one of the band pieces is formed with a branch pipe into which the other pipeline can be inserted, and the other pipe is connected to the branch pipe. A line piece is inserted so that the band piece formed with the branch pipe is put on the outer periphery of the one pipeline, and another band piece constituting the repair band is put on the remaining portion on the outer periphery of the one pipeline. These band pieces are welded to each other on the outer periphery of the one pipeline to form the repair band, and the repair band forms the one pipeline. Covering the outer periphery In this case, the other pipeline is removed from the vicinity of the branch portion by a predetermined length, and then a sealing means is inserted from the other pipeline through a sealing means for preventing fluid leakage from the other pipeline. Then, in the pipeline repairing method, the branching portion of the other pipeline is sealed from the one pipeline, and then the branching portion is covered with the repair band. An open / close valve that opens and closes another pipeline is attached. After the open / close valve is closed, the other pipeline is removed from the position of the open / close valve by a predetermined length, and then the inside of the open / close valve is opened. First penetrating means capable of penetrating is inserted into the branch portion via the sealing means, and the other pipeline branches from the one pipeline. Then, the open / close valve is removed from the root portion of the other pipeline, a temporary valve is attached to this portion, and then the sealing means is attached to the temporary valve to prevent fluid leakage while preventing fluid leakage. The first sealing means is removed, and then the temporary valve is closed. Next, after the sealing means is attached to the temporary valve, the temporary valve is opened, and the second valve capable of penetrating the inside of the temporary valve is provided. A sealing means is inserted into the branch portion through the sealing means to seal a branching portion of the other pipeline from the one pipeline, and after removing the temporary valve, the repair band Cover the bifurcation Pipeline repair method was adopted.
[0009]
According to this invention, the structure which provides a branch pipe in one of the band pieces which comprise a repair band, and inserts the said other pipeline in the inside is employ | adopted. As a result, even at the branch portion, it is possible to perform the repair by covering the repair band without replacing and replacing the pipeline in which the defect is formed. For this reason, the efficiency of repair work can be achieved.
[0010]
In addition, since the entire branch portion is covered with the repair band, the reliability after repair is high and permanent repair can be performed.
[0012]
According to the present invention, the branching portion of the other pipeline from the one pipeline is sealed by the sealing means, so that the fluid flowing through the one pipeline remains even after the one pipeline is removed. There is no release from the bifurcation. For this reason, it is possible to perform the repair work while the fluid is flowing through the pipeline. For example, when a repair target is a gas pipe, conventionally, it has been necessary to operate all the governor stations around the repaired portion to secure the supply amount or to stop the gas. Since it is not necessary to perform such work in the present invention, not only the time required for the work can be shortened, but also the labor cost of the governor station worker can be reduced.
[0013]
In addition, since the repair is performed without stopping the fluid flowing through the pipeline, it is not necessary to provide a separate bypass line. As a result, the repair time can be shortened and the cost can be reduced.
[0015]
For example, in the vicinity of the governor station, a branch portion between a main pipe and a bypass pipe is formed in the gas pipe. The bypass pipe is generally provided with an open / close valve in the immediate vicinity of the branching portion. This open / close valve is extremely useful when the diameter of the internal passage is small like a generally used high-pressure cock.
[0016]
That is, an existing opening / closing valve having a small internal passage diameter is replaced with a temporary valve having a large internal passage diameter so that a second sealing means originally used for performing a welding operation for covering the repair band with the branching portion can be inserted. Has been replaced. By performing this operation, a second sealing means such as a cheese stopper can be inserted. Thereby, even if it is a branched part to which the valve | bulb was connected so that 2nd sealing means, such as a cheese stopper, cannot be inserted, repair work can be performed, without discharging | emitting a fluid outside.
[0017]
Even when the existing open / close valve is removed, the first sealing means such as the parasol stopper is used, so that the fluid flowing through one pipeline is not discharged to the outside.
[0018]
According to the present invention, in the above-described pipeline repair method, the other pipeline is provided with a mounting flange for mounting the opening / closing valve and the temporary valve, and the second sealing means provides the one pipeline. After sealing the branching portion of the other pipeline, the mounting flange is cut from the other pipeline, and then the branching portion is covered with the repair band.
[0019]
According to the present invention, since the flange formed in the other pipeline is cut, the other pipeline can be accommodated therein without providing a large inner diameter of the branch pipe of the repair band.
[0020]
Further, in the present invention, in the pipeline repair method, after cutting the mounting flange, a diffusion means is attached to a cutting port of the other pipeline, and an incombustible gas is supplied to the inside of the diffusion means. The branching portion is covered with a repair band.
[0021]
As described above, in the present invention, the repair work is performed without stopping the fluid flowing through one pipeline. During the repair, the branch portion is sealed by the sealing means, so that the fluid is prevented from being discharged to the outside. However, the fluid may not be completely prevented from leaking. If the target of repair is a gas pipe, if a gas leak occurs, the operator may be poisoned by the gas, and if the repair band is welded to the branch, welding may occur. is there.
[0022]
According to the present invention, even if a gas leak occurs, the diffusion means such as the diffusion hose releases the gas at a position away from the operator, so that the operator can be protected. Further, by injecting a gas such as nitrogen gas into the inside of the diffusion hose, the leaked gas is prevented from mixing with air and prevented from igniting.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0029]
FIG. 1 shows a repair of a branching portion where a branch pipe 2 as another pipeline extends from a main pipe 1 as a pipeline according to a pipeline repair method according to an embodiment of the present invention. It shows a state. A defect 17 is formed in the vicinity of the branch portion in the main pipe 1, and the defect 17 is repaired using the repair band 3 according to the embodiment of the present invention. This pipeline repair method is a repair method in which the entire branch portion including the defect 17 is covered with the repair band 3, and repair is performed without blocking the flow of gas flowing through the main pipe 1.
[0030]
In this repair method, welding is performed so that the entire branch portion including the vicinity of the defect 17 portion of the main pipe 1 and the branch pipe 2 having a predetermined length from the root of the main pipe 1 is covered with the repair band 3. Then, the defect 17 is repaired. The branch pipe 2 is cut at a position away from the root of the main pipe 1 by a predetermined length, and a diffusion hose 30 serving as a diffusion means is put on the cut end. As will be described in detail later, the diffusion hose 30 prevents the gas flowing through the main pipe 1 from igniting and protects the operator from the gas flowing through the main pipe 1. Further, a cheese stopper 20 as a sealing means is inserted from the cut end of the branch pipe 2, and the inside of the portion where the branch pipe 2 branches from the main pipe 1 is sealed by the cheese stopper 20. Thereby, repair work can be performed without releasing the gas flowing through the main pipe 1 to the atmosphere.
[0031]
2 to 4 show details of the repair band 3 used in this repair method. The repair band 3 is composed of two band pieces 4 and 8 in which a substantially cylindrical member is divided in the circumferential direction, and is formed so as to cover the outer periphery of the main pipe 1 which is a repair portion.
[0032]
One band piece 4 includes a main body 5 that covers the outer peripheral surface of the main pipe 1 and a branch pipe 6 that extends radially outward from the side surface. The main body 5 is formed in an arc shape in cross section, and the other band piece 8 and side edges are welded to cover the outer peripheral surface of the main pipe 1 during repair. The branch pipe 6 is formed in a hollow shape so that the branch pipe 2 can be inserted therein, and the inside thereof communicates with the inner peripheral side of the main body 5. A flange 7 is formed at the tip of the branch pipe 6 so as to project outward in the radial direction. As will be described later, this flange 7 is for attaching an open / close valve that permits or stops the flow of gas in the branch pipe 2, and bolt holes 7a ... 7a for valve attachment are formed at four locations in the circumferential direction. Has been.
[0033]
The other band piece 8 has a shape that forms a half crack of the cylindrical body, and the cross-sectional shape thereof is formed in an arc shape. As shown in FIG. 3, the band piece 8 has a through-hole penetrating inside and outside at a lower portion thereof, and the through-hole is closed by a plug 9.
[0034]
In these two band pieces 4 and 8, grooves 3a are formed on the side edges 5a and 8a of the respective members that become the mating portions when the branch portions are covered, and the grooves 3a are welded to form 2 One repair band 3 is formed from the two band pieces 4 and 8. The groove 3 a is formed so that the outer peripheral side of the repair band 3 is widened, and these two band pieces 4 and 8 are welded from the outer periphery of the repair band 3.
[0035]
FIG. 5 shows the cheese stopper 20 inserted from the cut opening of the branch pipe 2 during repair. The cheese stopper 20 is formed so that the central portion in the axial direction swells outward in the radial direction, the sealed portion 21 having an elliptical cross-sectional shape, the handle 22 for expanding and contracting the sealed portion 21 in the axial direction, and the sealed It is comprised from the rod-shaped positioning member 25 attached to the front-end | tip of the part 21. FIG. The sealing part 21 is sandwiched between disk-like members 26 and 27 at its front and rear, and is expanded and contracted between these members 26 and 27. On the other hand, the handle 22 is composed of a rod-shaped rotating shaft 23 and a gripping portion 24 attached to the rear end of the rotating shaft 23, and the tip of the rotating shaft 23 is a disc shape provided on the rear end side of the sealing portion 21. The member 27 is attached. The handle 22 rotates the rotating shaft 23 with the grip portion 24 and transmits the rotation in a disk shape to expand and contract the sealing portion 21 in the axial direction.
[0036]
The sealed portion 21 that is expanded and contracted by the handle 22 is formed of a rubber member. When contracted in the axial direction, the central portion in the axial direction is expanded radially outward, and conversely, when stretched in the axial direction, The intermediate portion is reduced in the radial direction. Thus, when the cheese stopper 20 comprised is sealed in the inner surface of the branch part of the main pipe 1 and the branch pipe 2, as shown to Fig.5 (a), it extends to an axial direction, The intermediate part is shrunk | reduced. In this state, it is inserted from the cutting port of the branch pipe 2, and the sealing portion 21 is aligned with the branch portion. When positioning to a branching part, it is performed using the positioning member 25 attached to the front-end | tip. Details of how to use the positioning member 25 will be described later. And as shown in FIG.5 (b), it shrinks to an axial direction in a branch part, the intermediate part is expanded to radial direction outer side, and a branch part is sealed.
[0037]
A procedure for repairing the branch portion provided in the vicinity of the governor box 10 of the gas pipe by the repair method described above will be described below. FIG. 6 shows the periphery of the governor box 10 having a branch portion to be repaired in the vicinity thereof, and FIG. 7 shows a flowchart of the repair work. 8 to 21 are diagrams showing details of the repair work for each process.
[0038]
As shown in FIG. 6, the main pipe 1 of the gas pipe extends vertically from the natural ground GL to the ground, bends at a right angle from the ground surface at a predetermined height, and its tip extends horizontally. The tip of the filter reaches a cylindrical filter 11 installed on the front side of the governor box 10. This filter 11 is a device for filtering impurities contained in the gas flowing inside, and supplies a gas free of impurities to the governor box 10.
[0039]
In addition, a bypass pipe 2 as a branch pipe 2 having a small pipe diameter is communicated with a vertically extending portion of the main pipe 1 at a position slightly above the ground surface. The bypass pipe 2 extends vertically from the natural ground GL toward the ground so as to be parallel to the main pipe 1, the upper end of the bypass pipe 2 is bent at a right angle, and the tip of the main pipe 1 extends horizontally. Is directed to 1. And the front-end | tip is connected to the main pipe 1, The branch part from which the bypass pipe 2 branches from the main pipe 1 to the side is formed. A high-pressure cock 13 is provided at a portion of the bypass pipe 2 that extends horizontally. The high-pressure cock 13 is an open / close valve for permitting or stopping the gas flowing in the main pipe 1 from flowing into the bypass pipe 2.
[0040]
The bypass pipe 2 has a discontinuous portion in a horizontally extending portion, and flanges 2a and 2b projecting outward in the radial direction of the bypass tube 2 are formed at both ends of the discontinuous portion. On the other hand, the high-pressure cock 13 is provided with pipes 14, 14 extending in the front-rear direction, and flanges 14 a, 14 a are similarly formed on the distal ends of the pipes 14, 14 so as to project outward in the radial direction of the pipes. The high-pressure cock 13 is attached to the bypass pipe 2 by bolting flanges 14 a and 14 a of pipes 14 and 14 provided before and after the high-pressure cock 13 to flanges 2 a and 2 b formed at discontinuous portions of the bypass pipe 2.
[0041]
In the repair procedure described below, in the gas pipe connected to the governor box 10 as described above, if there is a defect 17 due to corrosion at a branch portion between the main pipe 1 and the bypass pipe 2, the defect 17 is removed. It is to be repaired. In the description of each process, the reference numerals in parentheses indicate the step numbers shown in the flowchart of FIG.
[0042]
First, in repairing, the pressure of the gas flowing through the main pipe 1 is reduced for safety (S1). Further, the high-pressure cock 13 is closed to prevent the gas flowing inside the main pipe 1 from flowing into the bypass pipe 2 (S2). Next, in order to secure a work area, the bypass pipe 2 is removed by a predetermined length (S2). What is removed is the portion downstream of the high-pressure cock 13. Since the high-pressure cock 13 is closed, no gas is released into the atmosphere.
[0043]
Next, as shown in FIGS. 8 to 10, the inside of the branch portion between the main pipe 1 and the bypass pipe 2 is sealed, and the high-pressure cock 13 is removed from the bypass pipe 2 (S3 to S5).
[0044]
As shown in FIG. 8, a stopper insertion unit 40 as a sealing means is attached to the flange 14a of the high-pressure cock 13 from which the bypass pipe 2 has been removed (S3). The stopper insertion unit 40 is formed of a cylindrical body, and a flange 41 is formed at the tip of the stopper insertion unit 40 so as to project outward in the radial direction. On the other hand, a seal member 42 for blocking the inside and outside is provided at the rear end of the stopper insertion unit 40. The stopper insertion unit 40 has a parasol stopper 50 with a leading end inserted therein. As will be described later, the parasol stopper 50 is inserted up to a branch portion between the main pipe 1 and the bypass pipe 2 to seal the branch portion, and includes a sealing portion 51 provided at the tip, and the sealing portion. And a support shaft 52 that supports 51 from behind. The sealing portion 51 is configured to swell when air is injected therein. Further, the inside of the support shaft 52 is hollow like a straw and communicates with the inside of the sealed portion 51. Air is supplied from the support shaft 52 to the sealing portion 51 so as to swell.
[0045]
The parasol stopper 50 has a sealing portion 51 accommodated therein so that the support shaft 52 penetrates a seal member 42 provided at the rear end of the stopper insertion unit 40. In this state, the stopper insertion unit 40 is It is attached to the cock 13.
[0046]
Next, as shown in FIG. 9, the high-pressure cock 13 is opened and opened (S3). Even in this state, since the sealing member 42 for preventing gas leakage is provided at the rear end of the stopper insertion unit 40, the gas flowing from the main pipe 1 to the stopper insertion unit 40 is released to the atmosphere. Never happen. And the parasol stopper 50 is penetrated by the high-pressure cock 13 made into the open state. In the sealed portion 51 of the parasol stopper 50, air is not supplied, and in a deflated state, there is almost no outward expansion in the radial direction. For this reason, the inside of the passage 13a of the high-pressure cock 13 having a small diameter can be easily penetrated.
[0047]
The parasol stopper 50 penetrating through the high-pressure cock 13 has its sealing portion 51 aligned with the joint portion between the main pipe 1 and the bypass pipe 2, and air is injected into the sealing portion 51. By injecting air into the sealing part 51, the sealing part 51 expands, and the joint portion between the main pipe 1 and the bypass pipe 2 is sealed (S4). In addition, it is good to mark beforehand the corresponding position of the support shaft 52 of the stopper insertion unit 40 so that this sealing part 51 may be correctly aligned with the junction part of the main pipe 1 and the bypass pipe 2.
[0048]
After the sealing portion 51 is expanded to seal the joint portion, the parasol stopper 50 is left as it is as shown in FIG. 10, and the stopper insertion unit 40 and the high-pressure cock 13 are removed from the bypass pipe 2 (S5).
[0049]
Next, as shown in FIGS. 11 to 13, an operation of attaching the temporary valve 55 to the flange 2b formed on the bypass pipe 2 is performed (S5 to S7).
[0050]
As shown in FIG. 11, the temporary valve 55 is bolted to the flange 2b of the bypass pipe 2 (S5). The temporary valve 55 is provided with pipes 56, 56 on the front and rear sides thereof, and flanges 57, 57 projecting outward in the radial direction are formed at the ends of the pipes 56, 56. The temporary valve 55 is mounted with one of the flanges 57 bolted to the flange 2 b of the bypass pipe 2. The temporary valve 55 is attached to the bypass pipe 2 in an open state, and the support shaft 52 of the parasol stopper 50 is passed through the temporary valve 55. Further, the stopper insertion unit 40 removed earlier is attached to the outside of the temporary valve 55 (S6). Also in this case, the support shaft 52 of the parasol stopper 50 is passed through the seal member 42 provided at the rear end of the stopper insertion unit 40.
[0051]
Next, as shown in FIG. 12, the air that has been injected into the sealing portion 51 of the parasol stopper 50 is discharged from the sealing portion 51. As a result, the sealing portion 51 that has sealed the joint portion between the main pipe 1 and the bypass pipe 2 contracts and can pass through the temporary valve 55. The contracted sealed portion 51 is extracted from the bypass pipe 2 and the temporary valve 55 to the stopper insertion unit 40 (S6). In addition, since the sealing member 42 provided at the rear end of the stopper insertion unit 40 seals the gas flowing into the stopper insertion unit 40, the gas flowing through the main pipe 1 is prevented from being released to the atmosphere. The Thereafter, as shown in FIG. 13, the cock 58 of the temporary valve 55 is closed, and the stopper insertion unit 40 is removed from the temporary valve 55 (S6).
[0052]
Next, as shown in FIGS. 14 and 15, an operation of sealing the joint portion between the main pipe 1 and the bypass pipe 2 again with the cheese stopper 20 shown in FIG. 5 is performed (S7, S8).
[0053]
As for the cheese stopper 20, the sealing part 21 is set inside the stopper insertion unit 40 so that the rotating shaft 23 penetrates the sealing member 42 provided in the rear part of the stopper insertion unit 40. In this state, the flange of the stopper insertion unit 40 is received by the flange of the temporary valve 55. Next, the cock of the temporary valve 55 is opened, and the sealing portion 21 of the cheese stopper 20 passes through the temporary valve 55 and is aligned with the joint portion between the main pipe 1 and the bypass pipe 2. In addition, even if the sealing part 21 of the cheese stopper 20 is in a state of being reduced in the radial direction, unlike the parasol stopper 50, the diameter thereof cannot be reduced to be small. Therefore, as the temporary valve 55, a ball valve having a large inner diameter of the communication path formed therein is selected.
[0054]
FIG. 14 shows a state where the sealing portion 21 of the cheese stopper 20 is aligned with the branch portion between the main pipe 1 and the bypass pipe 2. As shown in FIG. 14, the end of the rod-shaped positioning member 25 provided at the end of the sealing portion 21 is brought into contact with the inner peripheral surface of the main pipe 1, whereby the sealing portion 21 is aligned. The length of the positioning member 25 is formed to be approximately the same as the diameter of the main pipe 1. When the tip of the positioning member 25 is brought into contact with a position where the inner diameter of the main pipe 1 is opposed to the branched portion, the sealing portion 21 is naturally formed. It is comprised so that it may correspond to a branch part. The diameter of the main pipe 1 varies depending on the object to be repaired. Therefore, it is convenient to prepare several kinds of positioning members 25 in advance so that they can be selected according to the maintenance object.
[0055]
After the sealing portion 21 is aligned with the branch portion, as shown in FIG. 15, the sealing portion 21 is contracted in the axial direction, and the outer diameter is projected outward in the radial direction. By rotating the rotary shaft 23 by the grip portion 24 provided so as to extend radially outward from the rear end of the handle 22, the sealing portion 21 is contracted in the axial direction, and accordingly, the outer peripheral portion expands in the radial direction. . Thereby, the inside of a branch part is sealed by the sealing part 21 (S8).
[0056]
Thereafter, the temporary valve 55 and the stopper insertion unit 40 are removed from the bypass pipe 2 (S9). Further, as shown in FIG. 16, the bypass pipe 2 is cut at a portion between the flange 2 a and the main pipe 1 along a plane AA orthogonal to the axial direction, and the flange 2 a provided at the tip is removed ( S10).
[0057]
And as shown in FIG. 1, the whole branch part is coat | covered with the repair band 3 which consists of the two band pieces 4 and 8 (S11-S13). In the band piece 4 in which the branch pipe 6 is formed, the bypass pipe 2 from which the flange 2 b is removed is inserted into the branch pipe 6 so that the inner peripheral surface of the main body 5 is covered with the outer peripheral surface of the main pipe 1. . The other band piece 8 is arranged so as to face the band piece in which the branch pipe 6 is formed with the main pipe 1 interposed therebetween, and its side edge 8a is connected to the side edge 5a of the band piece 4 in which the branch pipe 6 is formed. The outer peripheral surface of the main pipe 1 is covered by alignment (S11).
[0058]
As shown in FIG. 17, a diffusion hose 30 is attached to the cut end of the bypass pipe 2 from which the flange has been removed (S12). Even if the gas in the main pipe 1 leaks, the diffusion hose 30 diffuses the gas to a position away from the work area and protects the worker from the gas. In addition, non-combustible gas supplied from the gas tank 31 is injected into the diffusion hose 30 to prevent the gas and air from being mixed even when the gas leaks from the main pipe 1. ing. Thereby, it is possible to prevent a spark or the like generated by welding performed in the next process from being ignited by the gas. Nitrogen gas may be injected as the non-combustible gas.
[0059]
After finishing the above operation, the band pieces 4 and 8 covering the 17 parts of the defect are welded (S13). First, as shown in FIG. 1, the repair band 3 is formed by welding from the grooves 3 a formed on both side edges 5 a and 8 a of the two band pieces 4 and 8. At this time, airtight welding is performed so as not to cause gas leakage from the welded portion. Next, the upper end edge and the lower end edge of the repair band 3 are hermetically welded to the outer peripheral surface of the main pipe 1 and sealed so that no gap is formed between the outer peripheral surface of the main pipe 1 and the main body portion 5 of the repair band 3. A state is formed.
[0060]
After the welding to the branch portion of the repair band 3 is finished, as shown in FIG. 18, it is inspected whether there is a welding defect by an infiltration flaw detection type inspection (S14).
In this inspection, if a welding defect is found, the defective part is immediately repaired.
[0061]
After the repair of the bifurcation performed as described above is completed, as shown in FIGS. 19 to 21, the work of reconnecting the bypass pipe 2 removed to the main pipe 1 is performed (S15˜). S20).
[0062]
FIG. 19 shows an operation of mounting the opening / closing valve 60 on the repair band 3 welded to the branch portion. After completion of the welding operation, the diffusion hose 30 attached to the cut port of the bypass pipe 2 is removed. After the release hose 30 is removed, a new opening / closing valve 60 is mounted on the flange 7 formed at the tip of the branch pipe 6 of the repair band 3 (S15). Also in the opening / closing valve 60, the inner diameter of the passage is formed to be relatively large so that the sealing portion 21 sealing the branch portion between the main pipe 1 and the bypass pipe 2 can pass through the inside of the opening / closing valve 60. It is advisable to use a ball valve.
[0063]
A stopper insertion unit 40 is attached to the flange 61 downstream of the opening / closing valve 60 to form a sealed state. After the stopper insertion unit 40 is attached, the sealing portion 21 of the cheese stopper 20 is reduced in the radial direction to release the sealing state, and the sealing portion 21 is pulled out to the inside of the stopper insertion unit 40 (S16).
[0064]
Thereafter, as shown in FIG. 20, the cock 62 of the opening / closing valve 60 is closed, and the opening / closing valve 60 is closed (S17). Then, the stopper insertion unit 40 attached to the opening / closing valve 60 is removed. After such work, the plug 9 provided on the main body 5 of the repair band 3 is once removed, and the nitrogen gas remaining between the inner surface of the repair band 3 and the outer peripheral surface of the main pipe 1 is released to the outside air. The After this gas purging, the plug 9 is firmly tightened to the repair band 3 and then the plug is welded. This reliably prevents the gas from leaking from the plug hole in which the plug 9 is tightened. After the plug is welded, the welded portion is inspected for penetration failure by penetration inspection, and if a welding failure is found, it is immediately repaired (S18).
[0065]
Thereafter, the pressure of the gas flowing through the main pipe 1 is increased to the original pressure, and the presence or absence of gas leakage is checked (S19). The check for gas leakage is simple and effective when the foamed liquid 70 is sprayed on the repair band 3 around the welded portion. After confirming that no gas leakage has occurred, an anticorrosive agent is applied to the entire branch portion covered with the repair band 3. Then, the bypass pipe 2 that has been removed is connected to the main pipe 1 again, and the repair work is completed (S20).
[0066]
As described above, the case where the existing valve is the high-pressure cock 13 has been described as an example. However, when the existing valve is a ball valve, the step of inserting the parasol stopper 50 into the branch portion and mounting the temporary valve 55 to the bypass pipe 2 is as follows. Omitted. Since the internal diameter of the passage formed in the high-pressure cock 13 is small, the high-pressure cock 13 cannot pass through the sealing portion 21 of the cheese stopper 20 that seals the inside of the branch portion during welding work. For this purpose, it is necessary to temporarily replace the ball valve that allows the sealing portion 21 of the cheese stopper 20 to pass therethrough. However, when the existing valve is a ball valve, the cheese stopper 20 can be directly inserted. For this reason, the replacement work to the temporary valve 55 shown in S4 to S6 shown in FIG. 7 is omitted.
[0067]
Further, in the vicinity of the governor box 10, the case where the repair method according to the present invention, the repair band 3 and the cheese stopper 20 as the sealing means are applied to the branch portion formed by the main pipe 1 and the bypass pipe 2 is taken as an example. Although explained, it cannot be overemphasized that it is applicable to the branch part of other gas pipes. Furthermore, the pipeline to be repaired is not limited to a gas pipe, and may be applied to a water pipe or other pipeline.
[0068]
In the above embodiment, the repair work is performed after reducing the gas pressure flowing inside, but depending on the fluid flowing through the pipeline, the repair work may be performed with the original pressure without reducing the pressure. Good.
[0069]
【The invention's effect】
As described above, according to the present invention, when repairing a branch part provided in a pipeline, excavation of a working mine, temporary installation of a separate bypass line, operation of all governor stations installed around the repair part, etc. There is no need to perform work accompanying the repair work. For this reason, the work efficiency can be improved and the cost required for repair can be reduced.
[0070]
In addition, since the entire branch portion including the defective portion is covered with the repair band, leakage from the repair portion can be prevented for a long period of time, and permanent repair can be performed instead of emergency treatment.
[Brief description of the drawings]
FIG. 1 is a view showing a state where a repair band according to an embodiment of the present invention is coated on a branch portion of a gas pipe.
FIG. 2 is a perspective view of a repair band according to an embodiment of the present invention.
3 is a partial cross-sectional side view of the repair band shown in FIG. 2. FIG.
FIG. 4 is a view showing a groove formed on a side edge of a band piece constituting a repair band.
FIG. 5 is an explanatory view showing the action of a cheese stopper used in the repair method of the present invention.
FIG. 6 is a view showing the periphery of a governor station in which a defective portion is repaired by the repair method of the present invention.
FIG. 7 is a flowchart showing a flow of a repair method according to an embodiment of the present invention.
FIG. 8 is a view showing a state where a stopper insertion unit is attached to a high-pressure cock that opens and closes a bypass pipe.
FIG. 9 is a view showing a state in which the sealing portion of the parasol stopper seals the joint portion between the main pipe and the bypass pipe.
FIG. 10 is a view showing a state where the high-pressure cock and the stopper insertion unit are removed from the bypass pipe.
FIG. 11 is a diagram showing a state in which a temporary valve and a stopper insertion unit are attached to the bypass pipe in a state where a joint portion between the main pipe and the bypass pipe is sealed with a parasol stopper.
FIG. 12 is a view showing a state in which the parasol stopper is removed from the joint portion between the main pipe and the bypass pipe.
FIG. 13 is a diagram showing a state in which the cock of the temporary valve is closed.
FIG. 14 is a diagram showing a state in which the sealing portion of the cheese stopper is aligned with the branch portion between the main pipe and the bypass pipe.
FIG. 15 is a diagram showing a state in which the sealing portion of the cheese stopper is expanded in the radial direction and the inside of the branch portion is sealed.
FIG. 16 is a diagram showing a position where the bypass pipe is cut to remove the flange.
FIG. 17 is a view showing a state in which a diffusion hose is attached to the cutting end of the bypass pipe.
FIG. 18 is a view showing a state in which a welding defect is inspected by a penetration flaw detection type inspection.
FIG. 19 is a view showing a state in which the sealed portion of the cheese stopper that has sealed the branch portion is pulled out to the stopper insertion unit.
FIG. 20 is a diagram showing an operation of performing a gas purge for releasing gas staying between the repair band and the main pipe.
FIG. 21 is a diagram showing a work for inspecting for gas leakage after the repair work is completed.
[Explanation of symbols]
1 Main (one pipeline)
2 Branch pipes, bypass pipes (other pipelines)
3 repair band
4,8 Band piece
5 Body
6 Branch pipe
13 High pressure cock
20 Cheese stopper
21 Sealing part
22 Handle
23 Rotating shaft
24 gripping part
25 Positioning member
30 Dispersion hose
40 Stopper insertion unit
50 Parasol stopper
51 Sealing part
52 Support shaft
55 Temporary valve
60 Open / close valve

Claims (3)

A repair method for a pipeline, in which a repair band is covered with a branch portion extending from one pipeline to another pipeline, and the repair band is composed of a band piece divided into at least two in the circumferential direction A branch pipe into which the other pipeline can be inserted is formed in one of the band pieces, and the branch pipe is formed by inserting the other pipeline into the branch pipe. The band piece is put on the outer periphery of the one pipeline, and the other band piece constituting the repair band is put on the remaining portion of the outer periphery of the one pipeline, and these band pieces are put on the one pipeline. periphery with and welded to each other to form the repair band, upon coating the outer periphery of the one pipeline in this repair band, the other pie A line is removed from the vicinity of the branch portion by a predetermined length, and then a sealing means is inserted from the other pipeline through a sealing means for preventing fluid leakage from the other pipeline, and the one pipe In a pipeline repairing method, sealing a branching portion of the other pipeline from a line, and then covering the branching portion with the repair band,
An opening / closing valve for opening / closing the other pipeline is attached to the other pipeline, and the other pipeline is removed from the position of the opening / closing valve by a predetermined length after the opening / closing valve is closed. Then, a first sealing means capable of penetrating the inside of the opening / closing valve is inserted into the branch portion via the sealing means, and a branching portion of the other pipeline from the one pipeline is sealed. Then, the open / close valve is removed from the root portion of the other pipeline, a temporary valve is attached to this portion, and then the sealing means is attached to the temporary valve to prevent fluid leakage and the first sealing. The temporary valve is closed after the means is removed, and then the temporary valve is opened after the sealing means is attached to the temporary valve. Then, a second sealing means capable of penetrating the inside of the temporary valve is inserted into the branch portion via the sealing means to seal a branching portion of the other pipeline from the one pipeline. And after removing the said temporary valve, the said branch part is coat | covered with the said repair band, The repair method of the pipeline characterized by the above-mentioned . The other pipeline is provided with a mounting flange for mounting the opening / closing valve and the temporary valve, and the second pipeline sealing unit seals a branching portion of the other pipeline from the one pipeline. 2. The method of repairing a pipeline according to claim 1 , wherein the mounting flange is cut from another pipeline later, and then the branching portion is covered with the repair band . After the mounting flange is cut, a diffusion means is attached to the cutting port of the other pipeline, an incombustible gas is supplied to the inside of the diffusion means, and then the branch portion is covered with the repair band. The pipeline repair method according to claim 2.

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