JPH0323327B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for coating the inner surface of existing pipes, for example, for restoring the functionality of existing aging pipes such as water pipes and gas pipes.

(Conventional technology) Cast iron pipes, steel pipes, asbestos cement pipes, etc. are used for water pipes and gas pipes, but as they age, rust lumps and deposits form on the inside of the pipes, resulting in a decrease in flow rate. Fluid may leak from pipe connections or defective parts, or red water may occur in the case of water supplies. As one of the various construction methods currently employed to restore the functionality of existing aging pipes, Japanese Patent Application Laid-Open No. 58-87018
Publication No. 162334, Japanese Patent Publication No. 162334, Japanese Patent Publication No. 1983-162334
There is a construction method described in Publication No. 167156, etc. As shown in Fig. 4, this construction method involves coating the inner surface of the pipe 1 with a lining tube 2 by heating and pressurizing it, and then forming a hole in the branch part 3 of the water faucet or supply pipe that is led into each home. The method used to open the tube was to fill the tube with high-pressure heated steam and burst the tube.

(Problems to be Solved by the Invention) In the conventional construction method described above, the lining tube 2 adhesively coated on the inner surface of the tube 1 must be made of a material that firmly adheres to the inner surface of the tube through, for example, an epoxy adhesive. In addition, the material is required to be easily perforated at the branch portion 3. By the way, if a tube whose inner surface is coated with adhesive by heating and pressurizing is made to have the above-mentioned properties, the mechanical strength of this tube will be considerably reduced by heating, and the elongation will be considerably large by applying pressure. It is required that it be a thing. Tubes made of materials with such performance are made by uniformly applying epoxy adhesive to the outer surface of the tube, drawing it into the tube, introducing air into the tube, allowing it to swell, and then replacing it with water vapor. During the process of adhering the tube to the inner surface of the tube using the pressure of heating and steam, extreme elongation occurs in the tube at joints and defective areas of the tube, causing the thin tube to elongate further and eventually break. It ruptures, making it impossible to achieve the initial purpose of coating the inner surface of the tube.

(Means for solving the problem) Therefore, in order to prevent the above-mentioned problems, the inside of the tube should be made to maintain considerable mechanical strength even under high temperatures, and be properly pressurized. This method uses a reinforcing tube that has the ability to cause a large amount of elongation and is thinner than the coating tube to prevent the tube from bursting during the process of adhesively coating the inner surface of the tube. The reinforcing tube may be inserted after the tube that covers the inner surface of the tube is drawn into the tube at the construction site, or
It goes without saying that it may be manufactured in a state in which it is inserted into the covering tube in advance at the factory.

After the tube has been adhesively coated on the inner surface of the tube in this way, the reinforcing tube has completed its role. Generally, materials with such performance as reinforcing tubes pose problems in terms of water quality, for example, in pipes that carry drinking water. Also, in drilling work at branch points,
It is difficult to open holes because it maintains considerable strength at high temperatures. Therefore, after the tube 2 is adhesively coated on the inner surface of the tube, the reinforcing tube 4 must be pulled out and removed. As a method for pulling out the reinforcing tube 4, as shown in FIG. 5, it is generally considered that the reinforcing tube 4 is pulled out from one end of the pipe in the direction of the arrow. However, since this reinforcing tube 4 is heated and pressurized during the process of adhering and coating the tube 2 on the inner surface of the tube, it is in close contact with the tube 2 on the inner surface of the tube and cannot be pulled out by pulling it from one end of the conduit. Not coming.

Furthermore, as the pipe becomes longer, such as 50 to 100 m, it becomes increasingly difficult to remove it. For this reason, it is conceivable to twist the reinforcing tube 4 to release the adhesive from the tube 2, but this method is also extremely difficult in the case of a long pipe.

Therefore, the present invention is designed to prevent the tube 2 from bursting during the coating process as described in the following examples.
Furthermore, it provides a method for easily removing the reinforcing tube 4 that is no longer needed.

(Example) Figures 1 to 3 are examples of the present invention. Figure 1 is an explanatory diagram of a method for coating the inner surface of a tube with a tube, and Figures 2 and 3 are explanatory diagrams of a method for removing a reinforcing tube. It is.

In FIG. 1, a tube 2 made of a polyethylene polymer and having an epoxy adhesive layer on its outer surface is drawn into a tube 1. This tube 2
On the inside of the tube 2, there is a reinforcing material made of a material that is thinner than the tube 2 and has high high temperature strength (strength near 100°C), such as polypropylene resin, nylon 66, nylon 11, nylon 12, polyurethane resin, silicone resin, etc. Tube 4 is inserted. The reinforcing tube 4 may be inserted in advance at a factory during the manufacturing process of the tube 2, or may be inserted at the installation site. tube 2
Both ends of the reinforcing tube 4 are folded outward and fixed as shown in FIG. 1, and the outside thereof is sealed with terminal jigs 5a and 5b.

An air introduction pipe 7 and a steam introduction pipe 8 are attached to one end jig 5a via a valve 6, and a fluid discharge pipe 9 is attached to the other end jig 5b. 10 is a pressure gauge.

Next, a method of coating the tube 2 on the inner surface of the tube will be explained.

First, open the valve 6a and insert low pressure (approximately 0.3 to 0.9 Kg/ ^cm2 ) air into the reinforcing tube 4, and inflate the reinforcing tube 4 and tube 2 sequentially from the left end to the right end. .

Next, the valve 6b is opened to introduce steam at a pressure slightly higher than the air pressure, and the valve 6c of the fluid discharge pipe 9 is opened to adjust the pressure.

As a result, the tube 2 is heated sequentially from the left end and is brought into close contact with the tube wall, and the air between the tube 1 and the tube 2 and within the reinforcing tube 4 is expelled to the right end. After the tube 2 is heat-bonded to the inner surface of the tube in this manner, air and water are introduced while maintaining the pressure inside the tube to cool the tube. When cooling is completed, remove the terminal jigs 5a and 5b at both ends, insert the tension wire 11 into the tube 1 as shown in FIG.
One end (the right end in the figure) of the reinforcing tube 4 is ripped off to this wire 11 and fixed with a binding wire 12. Reference numeral 14 denotes a slip-off prevention jig provided before and after the bind portion 13 to prevent slippage between the wire 11 and the reinforcing tube 4. 15 is a rope made of hemp, nylon, etc. connected to the rear end of the wire.

After the terminal is treated as described above, air 16 is fed into the reinforcing tube 4 from the left end in FIG. Enter. Then, when the tension wire 11 is pulled in the direction of the arrow, the reinforcing tube 4 is peeled off from the tube 2 while being turned inward, and can be easily taken out and removed from inside the tube.

In addition, when pulling the wire 11, in the unlikely event that a problem occurs (for example, the peeled reinforcing tube does not turn over due to the tension of the tension wire 11 and the entire reinforcing tube shifts toward the tension side, a so-called gearing phenomenon occurs, making it difficult to pull out). If the reinforcing tube 4 has deteriorated), by pulling the rear rope 15, the reinforcing tube 4 can be returned to its original state and the reinforcing tube 4 can be taken out and removed again.

In addition, when it is necessary to make a hole in the tube 2 such as a branch part, a hole making device (not shown) is used to make the hole. When the reinforcing tube 4 is removed, the inner surface coating of the tube is completed.

(Effects of the Invention) As described above, the present invention provides a reinforcing tube that is thinner than the tube and has greater high-temperature strength inside the tube, and expands the reinforcing tube by sending air or heated inflow into the reinforcing tube. Unlike methods in which the tube is expanded with air, heat, or pressurized fluid, this method does not have the drawback that the tube becomes thinner and stretches at joints or defective areas during the coating process, and eventually bursts. Further, since the reinforcing tube is thinner than the tube, it is easy to turn the end portion inward and pull it out for removal. Furthermore, if air is pumped in from the other end of the reinforcing tube (not the reversed side) and the reinforcing tube is pulled out in an inflated state, even if there is any problem during the pulling process, the thin-walled tube can be pulled back to the opposite side and restored to its original state. You can return to the state and start reversing again. Furthermore, when binding the end of the reinforcing tube to the wire, a pull-out prevention jig is fixed at the front and rear of the bind part, so that the bind part is locked with the pull-out prevention jig whether the wire is pulled out or pulled back. , no slipping occurs between the wire and the reinforcing tube. The reinforcing tube is inverted and removed after the tube is heated and pressure bonded and the tube is cooled, so the tube is completely adhered to the inner surface of the tube, so there is no risk of the tube peeling off when removing the reinforcing tube. It has many effects.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is an explanatory diagram of a method of coating the inner surface of a tube with a tube, FIGS. 2 and 3 are explanatory diagrams of a method of removing a reinforcing tube, FIG. 4 is an explanatory diagram of a conventional tube covering method, and FIG. 5 is an explanatory diagram of a common-sense method for removing reinforcing tubes. 1...Pipe, 2...Tube, 4...Reinforcement tube, 5...Terminal jig, 6...Valve, 7...Air pipe, 8...Steam pipe, 9...Fluid discharge pipe, 10... ...Pressure gauge, 11...Tension wire,
12...Binding line, 13...Binding part, 14
... Falling prevention jig, 15 ... Rope, 16 ... Air.

Claims (1)

[Claims] 1. In a method of coating the inner surface of a tube by heating, pressurizing and adhering the tube, on the inside of the tube,
A reinforcing tube with a thinner wall and greater high-temperature strength is provided than this tube, air is sent into the reinforcing tube to expand it, then heated and pressurized fluid is inserted to coat the inner surface of the tube, and after the coating is completed, the tube is The inside of the reinforcing tube is cooled, and the reinforcing tube and the rear end of the tension wire inserted into the reinforcing tube are fixed at one end of the reinforcing tube, and a tension wire rope is attached to the rear end of the tension wire. Connect the end of the rope provided on the opposite side to the pulling direction of the reinforcing tube, and inflate it by feeding pressurized fluid into the reinforcing tube from the other end of the reinforcing tube, which is not the opposite side of the reinforcing tube. A method for coating the inner surface of a tube, characterized in that one end of the reinforcing tube is turned inward and pulled out and removed by pulling a tension wire.