JPH0135236B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a pipe repair method for water pipes, gas pipes, etc.

[Conventional technology]

In existing gas piping buried underground, as the supplied gas (natural gas) dries due to the high-medium pressure supply method, the sealing material at the pipe joint turns into fine dust and scatters into the gas, causing gas to leak from the pipe joint. It may become. A known method for repairing pipe joints as described above while still buried is to use the pipe inner coating agent as it is as a sealant for the pipe joint, but in this case, the coating is thin, so It is not sufficient to maintain the airtightness of the pipe joint. However, lining the inner surface of the tube with tar, epoxy resin, etc. using a packer will thicken the coating, but it will not be effective in reinforcing the coarsely filled sealing material and preventing leakage. In this case, since the sealing material and the lining layer are not substantially integrated, there is a risk that the lining layer will crack from this location and break early, resulting in gas leakage.

[Problems to be solved by the invention]

Therefore, sealing is performed by impregnating the sealing material at the pipe joint with a penetrant from the inside of the pipe.
After that, the inner surface of the tube is coated,
A method has been proposed in which the impregnated sealant and the coating layer are integrated. However, in this case, it is necessary to perform each work individually, which has the disadvantage of doubling the construction time. Furthermore, if gas leaks from a pipe joint, fine dust is mixed in the sealing material, and if the penetrant is impregnated in this state, a sufficient sealing effect cannot be obtained.

[Means to solve the problem]

The present invention has been made based on the above circumstances, and includes a continuous series of suction removal of fine dust at a pipe joint, impregnating action of a penetrant at the pipe joint, and coating on the inner wall of the pipe. The purpose is to provide a pipe repair method that can be accomplished during the operation process. For this purpose, the present invention provides a construction method for coating the inner surfaces of pipes connected through several pipe joints, in which two pigs that move with their peripheral surfaces in airtight contact with the inner surface of the pipe are connected using a connecting rope. A coating pig whose outer diameter has a predetermined gap between it and the inner surface of the tube is fixed to the connecting rope at the front and back, and a penetrant is applied between the two pigs at the front, and a penetrant is applied between the two pigs at the rear. are each filled with coating agent, and while applying negative pressure to the front side of the front pig and positive pressure to the rear of the coating pig, each pig is pulled with a tow rope and moved. When the pipe joint is located between the pigs, the penetrant is applied to the pipe joint under pressure and infiltrated into the pipe joint, and as the pig advances, the coating agent leaks from the circumferential surface of the coating pig at the rear end and flows into the pipe joint. This method is characterized in that it simultaneously accomplishes filling and coating of the inner surface of the tube.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. In the figure, numerals 1, 2, and 3 are spherical pigs made of an elastic material such as rubber with a hollow interior. The pig 3 at the rear is for coating, and the outer diameter has a predetermined gap with the inner surface of the pipe.
are connected to each other by flexible ropes 4 and 5, respectively. The pig 1 at the front end and the coating pig 3 at the rear end are connected to traction ropes 6 and 7 on opposite sides thereof. Incidentally, if necessary, the ropes 6 and 7 are provided with scales 8 for measuring their moving lengths. Then, the above-mentioned pigs 1, 2 and 3 are introduced into the existing pipe 9 to be repaired, and during this introduction, a liquid phase such as an epoxy resin having a relatively low viscosity is applied between the above-mentioned pigs 1 and 2 by an appropriate means. Fill with penetrant A. Further, a liquid phase coating agent B such as a relatively high viscosity epoxy resin is filled between the pigs 2 and 3. In this state, in the present invention, negative pressure P ₁ is applied to the existing pipe 9 in the front space of the front pig 1 to move it by suction,
In addition to the negative pressure, the towing rope 6 is pulled in the direction of the arrow. In short, there is negative pressure in the front space of pig 1.
Move each pig with P ₁ applied, and connect pipe fitting 1
0 should be between the pigs 1 and 2 above. In this way, negative pressure P ₁ is created in the front space of pig 1.
Due to the suction action of It starts to be suctioned and discharged. In addition, the traction resistance of the pig is reduced,
It moves smoothly not only in straight pipes but also in curved pipes. Then, with pigs 1 and 2 moving,
Supply pressurized gas (pressurized air) at an appropriate pressure P ₂ from the rear pipe end, and connect both pigs 1 and 2, 2 and 3.
Penetrant A and coating agent B filled in between
Positive pressure is applied through pigs 2 and 3. Due to this pressurization, the penetrating agent A is penetrated and impregnated into the seal material 11 of the pipe joint part 10 made of hemp skin etc. At this time, as mentioned above, dust in the seal material 11 of the pipe joint part 10 Objects are suctioned and removed by negative pressure, and since the interior of the pipe joint 10 is under negative pressure, the penetrating agent A has good permeability and the sealing effect is enhanced. Next, when the pigs 1, 2, and 3 are moved forward, the coating agent B leaks from around the coating pig 3 at the rear end, fills the pipe joint 10, and forms a coating layer on the inner wall surface of the pipe. 12
form. The thickness of this coating layer 12 is
By appropriately setting the gap G between the circumferential surface of the pig 3 at the rear end and the inner wall surface of the pipe, an appropriate coating layer thickness can be obtained. In addition, even if penetrant A and coating agent B are consumed during the work and their storage capacity is reduced, positive pressure is applied from the rear of coating pig 3 and the penetrant A and coating agent B are applied by the pigs 2 and 3. Since the pipe is pressurized, the penetration of the penetrant A into the pipe joint part 10 and the formation of a coating layer on the inner surface of the pipe are uniformly performed. In this way, the suction action on the pipe joint part 10, 1
The subsequent impregnation action, secondary filling action, and coating action can be performed continuously and simultaneously during one movement of the pig, resulting in high work efficiency and significant cost reduction. Moreover, the pipe joint part 10 after removing fine dust
The sealing material 11 impregnated with the coating layer can be integrated with the coating layer with sufficient strength, and sealing can be performed well. In addition, if there is a branch pipe 13 in the middle of the pipe, it is of course possible to supply pressurized gas to the branch pipe 13 to prevent the penetrating agent A and coating agent B from flowing there. be.

【Effect of the invention】

As detailed above, the present invention connects the pigs 1 and 2 back and forth with the connecting rope 4,
A coating pig 3 is fixed to the connecting rope 5 behind the pig 2, and a penetrating agent A is filled between the pigs 1 and 2, a coating agent B is filled between the pigs 2 and 3, and the pig 1 is pulled with the towing rope 6. As a result, the movement of each pig 1, 2, and 3 within the pipe having the pipe joint part 10 is ensured, and the penetration of the penetrant A into the pipe joint part 10 and the formation of a coating layer on the inner surface of the pipe are ensured. can be done simultaneously and reliably, making repair work more efficient and significantly shortening construction time. Since negative pressure is applied to the front of the pig 1 while pulling the pigs 1, 2, and 3 with the towing rope 6, the dust inside the pipe joint 10 and the pipe 9 before repair is sucked out of the pipe by the negative pressure. The pipe joint part 10 is discharged to a negative pressure, and the permeability of the penetrant A to the sealing material 11 in the pipe joint part 10 is improved, increasing the sealing effect, and the coating agent B applied afterwards. The integration of the coating agent B is performed well, and the subsequent adhesion of the coating agent B to the inner surface of the tube is performed well. (3) Pig 1 connected by connecting ropes 4 and 5,
Since positive pressure is applied to the rear of pig 3 (coating pig) while towing 2 and 3 with a towing rope 6, the amount of penetrating agent A between pigs 1 and 2 and coating agent B between pigs 2 and 3 is Even if the amount decreases while the pipe repair work is in progress, the pig 3 is pushed by positive pressure to push the coating agent B and the penetrant A through the pig 2 to the pipe joint 10. The penetration and filling of the penetrant A and the coating treatment of the coating agent B from the inner surface of the pipe fitting 10 to the inner surface of the pipe can be uniformly performed. Effects such as this can be obtained.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention;
FIG. 2 is a longitudinal side view showing the situation after the work is completed. 1, 2, 3...Pig, 4, 5...Rope, 6,
7... Towing rope, 8... Scale, 9... Existing pipe,
10...Pipe joint part, 11...Sealing material, 12...
Coating layer, 13...branch pipe, A...penetrating agent,
B...Coating agent.

Claims (1)

[Claims] 1 In a method of coating the inner surfaces of pipes connected through several pipe joints, two pigs that move with their peripheral surfaces in airtight contact with the inner surface of the pipe are connected back and forth with a connecting rope, and the Coating pigs whose outer diameter has a predetermined gap between them and the inner surface of the pipe are fixed to the connecting rope, and a penetrant is filled between the two pigs at the front, and a coating agent is filled between the two pigs at the rear. While applying negative pressure to the front side of the front pig and positive pressure to the rear of the coating pig, move each pig by pulling it with a tow rope, and position the pipe joint between the two front pigs. When doing this, infiltrate the pipe joint with a penetrant under pressure,
A pipe repair method characterized in that coating agent is leaked from the circumferential surface of the coating pig at the rear end during the progress of the pig, thereby filling the pipe joint and coating the inner surface of the pipe at the same time.