JP2735857B2 - Inner surface lining method of pipe and lining pipe - Google Patents

Description

The present invention relates to an inner surface lining method for pipes, that is, a water pipe,
As a simple repair method for underground pipes such as gas pipes, the present invention relates to a lining method for separately lining a pipe on the inner surface thereof and a lining pipe used therefor.

Conventional technology and its problems Conventionally, as an inner lining method for repairing an existing pipe that has cracks or other damage as described above, a flexible synthetic resin tube is used as a lining material, and this is used in a pipe to be lined. A method is known in which a pressurized fluid is introduced and expanded after being inserted into a target tube via an adhesive.

However, in the case of using this method, it is necessary to apply an adhesive to the outer surface of the tube or the inner surface of the existing target tube, and this operation is not only considerably complicated, but also often causes a poor adhesion part, In addition, there is a great risk that the tube may be peeled off from the inner surface of the tube, and there is an essential and serious problem that the reliability of the lining condition is poor.

In addition, as a conventional proposal for solving such a problem, a synthetic resin pipe having a shape retaining shape having an outer diameter smaller than the inner diameter of the pipe to be lined was used as a lining pipe, and this was inserted into the target pipe. After that, a lining method (Japanese Patent Laid-Open No. 63-162221) is used in which the pipe is expanded by conducting a pipe for expansion into the inside in a state where the pipe is heated and softened from the inner side so that the pipe is brought into close contact with the inner surface of the target pipe. A tube made of a synthetic resin having the same shape-retaining property but having an outer diameter corresponding to the inner diameter of the target pipe is used as the pipe body, and the cross-section is deformed so as to reduce the outer diameter. Then, a lining method has been proposed in which the pipe is heated and pressed from the inner surface side to restore the original shape, so that the pipe is brought into contact with the inner surface of the target pipe (Japanese Patent Laid-Open No. 63-63).
203316) has been proposed.

However, in the case of the method according to the preceding proposal,
There is no problem if the pipe to be lined is of a straight type having a relatively short length and no bent part. If the target pipe is long and has a bent part, the lining pipe Insertion of the body cannot be performed smoothly, making the insertion work difficult and severely impossible to construct, or if the lining pipe is forcibly pulled for insertion, the pipe will be in strong sliding contact with the inner surface of the target pipe. The body is torn, or deeply abraded even if not torn,
As a result, there has been a problem that the lining tube is torn or cracked when the tube is expanded or restored.

The present invention has been made to further solve such a problem.

Means for Solving the Problems The present invention uses a thermoplastic synthetic resin pipe having the same shape preserving property as the conventional lining pipe body as the lining pipe body, but has a plurality of convex sections along the axial direction on the outer peripheral surface. The use of the ridges allows the lining tube to be easily inserted into the bent portion of the pipe to be lined without hindrance by the traction operation under the heat-softening state, and the heat-softening and expansion after the insertion. The pipe operation can be easily performed by introducing a high-temperature fluid into the lining pipe.

That is, the present invention provides a lining tube to be lined with the inner surface of the target tube, which is made of a thermoplastic resin tube having an apparent outer diameter smaller than the inner diameter of the target tube, and is continuous with at least a part of the outer peripheral surface in the axial direction. A pipe having a shape-retaining property in which a plurality of raised ridges are formed as a group of knurled ridges, and the pipe is pulled from one end while being softened by heating by introducing a high-temperature fluid into the inside of the object. Inserting into the pipe, then increasing the pressure of the high-temperature fluid, expanding the pipe body, and bringing it into close contact with the inner surface of the target pipe, and then cooling and solidifying the pipe. The lining tube is the gist.

The types of pipes requiring repair to which the lining method of the present invention is applied include, for example, existing fluid transfer pipes such as water pipes, city gas pipes, exhaust pipes, and storage pipes such as electric wiring, and metal pipes and fumes. Pipes, asbestos pipes, synthetic resin pipes and the like.

The lining tube to be lined with the inner surface of the target tube by applying the method of the present invention is made of a thermoplastic resin such as polyvinyl chloride, polyethylene, or polypropylene, and has a sufficient shape-retaining property at room temperature, so-called hard tube. A synthetic resin tube is used.

The tubular body is usually formed by extrusion molding, and has a small apparent outer diameter (diameter of a circumscribed circle connecting the tips of the ridges) within a range of about 95 to 60% of the inner diameter of the target pipe. What was done is used. This outer diameter is 95 times the inner diameter of the target pipe.
%, The insertion operation into the target pipe becomes difficult, and if it is thinner than 60%, when it is expanded in the radial direction after insertion into the existing target pipe, significant unevenness in the peripheral wall may occur, There is a risk that cracks may occur in the thinned portion. Most preferably, the apparent outer diameter of the tube is preferably about 90 to 70% of the inner diameter of the target tube. The wall thickness of the tube is set to be slightly larger in advance so that the wall thickness required when the tube is finally lined on the inner surface of the target tube is secured. Usually, the required wall thickness after lining is in the range of about 1 to 10 mm.
It is appropriately determined according to the diameter, the expansion rate, and the like.

Further, the lining tube body is formed by integrally forming a plurality of ridges, such as triangular trapezoidal cross sections, which are continuous in the axial direction on at least a part of the outer peripheral surface thereof as a group of knurled ridges. This mainly reduces frictional resistance due to sliding contact with the inner surface of the target tube when inserting the tube, and facilitates the insertion operation by serving as a guide, and protects the surface of the tube to cause deep abrasions or tears. Is prevented from occurring. Therefore, the above-mentioned group of ridges may be formed on the entire outer peripheral surface of the tube. However, in order to reduce the contact area with the target tube during insertion and to reduce frictional resistance as much as possible, It is preferable that the pipes are separated at a plurality of positions in the circumferential direction and are arranged at equal intervals. For example, it is generally and preferably arranged about 4 to 10 strips at equal intervals on the outer peripheral surface of the tube.

In addition to the use of a tube with a circular cross section, for the sake of convenience in storage or transportation, the tube formed with a group of ridges is extruded and then heated and softened again to deform the cross section into a flat shape. In this state, it may be wound and supplied to a winding device.

In the lining operation using the lining tube, first, a high-temperature fluid such as high-temperature steam is introduced into the tube from one end thereof, whereby the tube is heated and softened from the inner surface side. Then, while maintaining this softened state, it is pulled into the target pipe by a pulling means such as a wire connected to one end, and the lining pipe is inserted over the entire length of the pipe. At this time, the group of ridges improves the penetrability of the target tube by contacting the tip of the ridge with the inner surface of the target tube.
Therefore, it is possible to smoothly insert the pipe body even in a bent portion of the target pipe.

Next, after the insertion is completed, one end of the tube is closed, and the pressure of the high-temperature fluid introduced from the other end is increased to expand the tube in the radial direction. Then, after the outer surface of the tube is brought into close contact with the inner surface of the target tube by this inflation operation, the fluid introduced into the inside is replaced with a low-temperature fluid, and the tube is cooled and solidified to complete the desired lining.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 to FIG. 4 show construction examples in which lining is applied to the inner surface of a target pipe (A) having bent portions (A1) and (A2) by the method of the present invention.

Here, as the lining tube (1), a tube made of a thermoplastic synthetic resin having an apparent outer diameter (l2) in a range of 95 to 60% smaller than the inner diameter (l1) of the target tube (A). A group of ridges (2) having a predetermined width formed by forming a plurality of ridges (2a) having a substantially triangular cross section in a zigzag cross section is arranged in six rows at predetermined intervals on the outer peripheral surface. The one formed and used is used. The above-mentioned tube (1) is a type generally called a hard tube extruded into a circular cross section together with a group of ridges (2) with vinyl chloride resin, for example, and has sufficient shape retention properties at ordinary temperature. It is.

At the time of lining, first, the above-mentioned tube (1) is heated from the inner surface side by introducing a high-temperature fluid such as steam from one end thereof to a temperature slightly exceeding the softening temperature of the resin of the tube.
For example, in the case of vinyl chloride, it is heated to a temperature of about 80 to 95 ° C. Therefore, the tube (1) is softened by this heating. Therefore, while maintaining the heat-softened state, the tube (1) is lined by pulling it with a wire connected to one end thereof via a connection fitting (3) or with a rope (4) such as a rope. It is drawn into the target tube (A) to be inserted and inserted over its entire length. During this insertion process, in order to maintain the softened state of the tube (1), a connecting fitting (3) attached to one end of the tube (1) has a through hole (5), or communicates with the outside at the tube end. It is necessary to maintain the circulation of the high-temperature fluid (G) introduced from the other end as a through hole. During such insertion operation, the outer peripheral surface is slid on the inner surface of the tube (1), the inner surface of the target tube (A), particularly the bends (A1) and (A2). Since the sliding property is improved and guided by the sliding property, the pipe (1) is relatively smoothly moved and inserted in the target pipe (A).

When the insertion of the tube (1) is completed, the distal end is expanded in advance as shown in FIG. 3 and a plug (6) is attached to the expanded end, or one end is inserted by any other method. Close hermetically. Then, the pressure of the high-temperature fluid (G) supplied from the fluid supply mouthpiece (7) at the other end is increased, and the inner pressure is increased to expand the pipe (1) in the radial direction, thereby to reduce the pressure of the target pipe (A). Let it adhere to the inner surface. The pressure applied here should be approximately 0.4 to 2.0 kg / cm ² .

Thereafter, the plug (6) is removed, and a low-temperature fluid such as cooling air is supplied from the fluid supply port (7) to cool and solidify the pipe (1) and to remove excess portions at both pipe ends. Resection to complete the desired lining.

In practice, such a lining method is often performed not only for short pipes but also for long pipes having a length of more than 10 m and 20 to 30 m. In a long lining tube corresponding to such a long target tube, it is often difficult to handle the lining tube in a straight tube form in terms of transportation and storage. Therefore, in such a case, the tube (1) is manufactured to have a slightly flat cross section, and is transported to the site in a state where it is wound by a winding device.
It is desirable that the material be heated and softened in that state and inserted into the target pipe so that the pipe is restored to its original circular shape when the inflation operation is performed.

 FIG. 5 shows a modified example of the lining tube.

This tube (11) is provided with a large number of ridges (2a) over the entire outer peripheral surface thereof, and a reinforcing thread (8) composed of a large number of tensile fibers is provided inside the peripheral wall at predetermined intervals. It is buried in. The reinforcing yarn (8) may be any material having tensile strength and a certain degree of heat resistance, and various types of synthetic fibers, natural fibers, and inorganic fibers are used. In the case of the pipe body (11) in which the reinforcing thread (8) is embedded, the tensile strength of the pipe body due to heat softening is compensated for at the time of insertion into the target pipe (A), and harmful elongation is prevented. The insertability into a long-span target pipe or a target pipe having a bent part can be improved.

Advantageous Effects of the Invention The present invention is to perform traction insertion into a target pipe in a state in which a lining pipe is heated and softened by introducing a high-temperature fluid into the lining pipe, and the pipe has a relatively free flexible property. In addition to having a group of ridges on the outer peripheral surface, the group of ridges comes into contact with the inner surface of the target pipe, and at the same time reduces frictional resistance and acts as a guide. Enables smooth retraction and insertion. In particular, even when the target pipe has a bent portion, it can be smoothly inserted along the pipe without any trouble. And, after the insertion, the pressure of the heating fluid is increased to expand the softened lining pipe body, and the solidified pipe is brought into close contact with the inner surface of the target pipe and then cooled and solidified, so that the target pipe is a curved pipe, a different-diameter pipe, Alternatively, even in the case where there is some unevenness or a step on the inner surface, the desired lining can be applied without any trouble.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a step of inserting a lining tube into a target tube having a bent portion, FIG. 2 is a perspective view of the lining tube, and FIG. 3 is expanded to bring the tube into close contact with the target tube. FIG. 4 is a schematic explanatory view of an inflation process, FIG. 4 is a cross-sectional view of a pipe line after lining is performed, and FIG. 5 is a perspective view showing a modified example of a lining pipe. (A) ... target pipe, (1) ... lining pipe,
(2) ... group of ridges, (2a) ... ridge, (3) ... connecting bracket, (4) ... tow rope, (5) ... through hole, (6) ...
... stopper, (G) ... high temperature fluid.

Claims (3)

(57) [Claims] 1. A lining pipe to be lined with an inner surface of a target pipe, which is made of a thermoplastic resin pipe having an apparent outer diameter smaller than an inner diameter of the target pipe, and is continuous with at least a part of an outer peripheral face in an axial direction. A pipe having a shape-preserving property in which a plurality of ridges are formed as a group of knurled ridges is drawn from one end while being softened by heating by introducing a high-temperature fluid into the target pipe. The inner surface lining method of a pipe, wherein the pressure of the high-temperature fluid is increased to expand the pipe body so that the pipe body is brought into close contact with the inner surface of the target pipe, and then cooled and solidified. 2. A lining pipe which is inserted into a target pipe and then expanded to come into close contact with the inner surface of the target pipe. The lining pipe is made of a thermoplastic resin pipe whose outer diameter is smaller than the inner diameter of the target pipe. A tube for inner lining of a pipe, wherein a plurality of ridges continuous at least in the axial direction are formed as a group of knurled ridges. 3. The tube for lining the inner surface of a tube according to claim 2, wherein the group of ridges is formed at a plurality of positions in the circumferential direction of the tube at equal intervals.