JPH035868B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention mainly relates to a repair method for plugging a hole due to corrosion in a small diameter pipe attached to an existing buried main pipe, and the repaired small diameter pipe.

Conventional technology and problems There is currently no suitable repair method for plugging holes caused by corrosion in small-diameter pipes attached to existing buried main pipes, so the pipes are dug up and sheath pipes around the main pipe are dug up. After cutting out the pipe, the small diameter pipe was removed and replaced. There is also a lining method in which pressurized fluid is used to push the lining material inserted between two pigs, but with this method, the hole is temporarily closed when the pig passes, but after the pig has passed, the pressurized fluid The drawback was that the lining agent that was blocking the hole was blown away.

In order to solve these problems, the present applicant has developed a method for repairing leaks in small diameter pipes, as disclosed in Japanese Patent Application No. 101893/1983. This method involves blowing compressed air from behind a wire extension line that has an umbrella-shaped pig at the tip, inserting the line into a small-diameter pipe, and inserting a guiding wire into the small-diameter pipe using the line. Then, as shown in Figure 3A, connect the front and rear pigs at a predetermined interval, and pull the wire through the small diameter pipe with high viscosity repair agent filled between both pigs to locate the leak hole. In this method, the repair agent that is blown outward from the leakage hole automatically hardens in that area and closes the hole without detecting it in advance. This method has been practically confirmed to be very effective as a repair method for general leakage holes caused by corrosion, but if the hole caused by corrosion is large, as shown in Figure 3B,
Even after repeated repairs using this method, there were cases in which the repair agent that had blown out to the outside dripped down before hardening and the hole was not closed.

Means for Solving the Problems The small diameter pipe leak repair method and the repaired small diameter pipe of the present invention have the following configuration as means for solving the above problems.

(1) A rubber bag for airtightness inspection with a guidance wire connected to the front end and a pressure tube connected to the rear end is pulled to the end of the pipe, and then returned from the end of the pipe at a fixed interval to remove the rubber bag for airtightness testing. A leak hole position discovery process in which internal pressure is applied to bring the pipe into close contact with the inner wall of the pipe, and air pressure is applied to the pipe at regular intervals to inspect the airtight state, and this process is repeated to confirm the presence or absence of leakage in a certain section. Then, the pig fixed to the guide wire is inserted from the tube end to a position with sufficient margin relative to the leakage hole position, and then the flexible tube is inserted from the tube end and its tip is A step of inserting the tube into contact with the pig, a repair agent injection step of injecting a high viscosity repair agent between the flexible tube and the small diameter tube through the LA coupling provided at the tube end, and a step of removing the wire. A repair method that further includes a pig removal process in which the pig is scraped off using a boring machine after the repair agent has hardened.

(2) Insert a flexible tube into a small-diameter pipe that is suspected of having a leak hole, and apply a high-viscosity repair agent to the flexible tube and the small-diameter pipe through an LA coupling installed at the end of the small-diameter pipe. Repaired small-diameter pipe made by injecting and hardening between the pipes.

Function The present invention uses the method disclosed in Japanese Patent Application No. 62-101893 to insert a guiding wire into a pipe, detects the position of a leakage hole using the guiding wire, and detects the position of a leakage hole by using the guiding wire. A method of partially repairing by placing a fixed pig in a position with sufficient margin beyond the leakage hole and injecting a high viscosity repair agent from the LA coupler at the end of the pipe, and using the above-mentioned guiding wire. This method targets small-diameter pipes that have been repaired by inserting a flexible wire through all of the small-diameter pipes that are suspected of having leakage holes, and then injecting a repair agent.

As the high-viscosity repair agent, for example, a two-component mixed metal powder-containing epoxy resin having a specific gravity of 1.6 to 1.8, a viscosity of 70,000 to 100,000 cp, and a curing time of about 1 hour, and various other types can be used.

As the flexible tube, for example, in addition to one produced by drawing a pipe, a flat-shaped spiral tube formed by spirally forming a metal strip can also be used.

Embodiment FIGS. 1A and 1B are cross-sectional views showing an example of the leak hole position discovery process in the method of the present invention, in which 1 is a small diameter pipe, 2 is a guiding wire, 3 is a rubber bag for airtightness inspection, 4 is a pressure tube, and 5 is an LA coupling. As shown in FIG. 1B, air pressure is applied to the pressure tube 4 at a certain distance from the end of the tube to inflate the rubber bag 3 and bring it into close contact with the inner surface of the small diameter tube 1, and then air pressure is applied to the LA coupling 5 so that the Inspect whether there is a drop in air pressure, and if there is no drop, move the rubber bag 3 to the next point at a certain interval and perform the same test. By repeating this operation, the location of the leak hole can be discovered. .

2A and 2B are cross-sectional views showing one example of partial repair according to the present invention, in which 1 is a small diameter pipe, 2 is a guiding wire, and 5 is an LA coupling. The wire 2 with the pig 6 attached is drawn into the tube, and the flexible tube 7 is inserted from the tube end to a predetermined position.
Inject high viscosity repair agent 8 from LA coupling 5. After injecting the repair agent, the wire 2 is pulled out, and after the repair agent has hardened, the pig 6 is scraped off using a boring machine to complete the repair as shown in FIG. 2B.

FIGS. 2C and 2D are cross-sectional views showing one example of the overall repair of the present invention. 1 is a small-diameter pipe in which a flexible tube 7 made of metal or the like is inserted over the entire length, and a high-viscosity repair agent 8 is applied from the LA coupling 5. Inject and cure to complete the repair.

According to the example, a flexible tube with an inner diameter of 10.5 mm was used for a small diameter tube with an outer diameter of 27.2 mm and an inner diameter of 19.4 mm, and partial and total repairs were performed with good results.

In addition, a small diameter tube with an outer diameter of 34.0 mm and an inner diameter of 25.0 mm was completely repaired using a flexible tube with an inner diameter of 13.0 mm, and good results were obtained.

Effect of the invention (1) The location of leakage holes in small diameter pipes can be confirmed.

(2) Even if the leak hole is large, the repair agent will not drip and can be repaired reliably.

[Brief explanation of the drawing]

Figures 1A and B are cross-sectional views showing an example of the leak hole position discovery process of the present invention, Figures 2A and B are examples of partial repair, and Figures C and D are examples of total repair. 3A and 3B are cross-sectional views showing a conventional example. The symbols in the drawings indicate the following members, respectively. 1: Small diameter tube, 2: Guidance wire, 3: Rubber bag for airtightness inspection, 4: Pressure tube, 5: LA
Coupling, 6: Pig, 7: Flexible tube, 8: High viscosity repair agent.

Claims (1)

[Claims] 1. A rubber bag for airtightness inspection with a guiding wire connected to the front end and a pressure tube connected to the rear end is pulled to the end of the pipe, and then returned from the end of the pipe at a fixed interval to perform the airtightness test. Applying internal pressure to the rubber bag used to make it stick to the inner wall of the pipe, and applying air pressure inside the pipe at regular intervals to check the airtightness, and repeating this process to check whether there is a leak in a certain section. Next, the pig fixed to the guiding wire is inserted from the tube end to a position with sufficient margin relative to the leakage hole position, and then the flexible tube is inserted from the tube end. A tube insertion step in which the tip thereof is brought into contact with the pig, a repair agent injection step in which a high viscosity repair agent is injected between the flexible tube and the small diameter tube through the LA coupling provided on the tube end side, and then the wire A method for repairing leakage in small-diameter piping, characterized by a combination of a extraction step of the repair agent and a pig removal step of scraping off the pig with a boring device after the repair agent has hardened. 2. Insert a flexible tube into a small-diameter pipe in which a leakage hole is suspected to exist, and apply a high-viscosity repair agent between the flexible tube and the small-diameter pipe through an LA coupling installed at the end of the small-diameter pipe. A repaired small-diameter pipe characterized by having been injected and hardened between the pipes.