JPH02202432A - Inner face lining method of pipe and pipe for lining - Google Patents

Abstract

PURPOSE:To insert a pipe easily into a curved section of another pipe to be lined without any trouble by pulling in the heated and softened state by using a thermoplastic synthetic resin pipe with shape retention properties having a plurality of projected lines along the axial line on the outer peripheral surface. CONSTITUTION:A thermoplastic synthetic resin pipe, having an apparent outer diameter l2 made smaller by the range of 95-60% to the inner diameter l1 of another pipe A to be lined and having a projected line group 2 of given width consisting of a plurality of projected lines 2a of almost triangular section formed into the section in zigzag knurled state and disposed and arranged in six lines at the given intervals on the outer peripheral surface, is used. While heat- softened state is retained, the pipe 1 is pulled by a cable 4 such as a wire or a rope connected with a connecting fittings 3 at its one end, drawn into the pipe A to be lined and inserted therein all over its whole length. The pressure of high temperature fluid C fed from a fluid feeding cap 7 on another end is increased to increase the internal pressure, expand the pipe 1 in the radius line direction and adhere the same to the inner face of the pipe A to be lined.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is directed to a method for lining the inner surface of a pipe, that is, as a simple repair method for underground pipes such as water pipes and gas pipes, the inner surface of the pipe is lined with a separate pipe body. This invention relates to a lining method and a lining pipe used therein.

Conventional technology and its problems Conventionally, as an inner lining method for repairing existing pipes that have cracks or other damage, a flexible synthetic resin tube is used as the lining material, and this is placed inside the pipe to be lined. A known method is to insert the tube into the tube, expand it by introducing pressurized fluid, and attach it to the inner surface of the target pipe using an adhesive.

However, when using this method, it is necessary to apply adhesive to the outside surface of the tube or the inside surface of the existing target pipe, which is not only quite complicated, but also often results in poor adhesion. There was a substantial and serious problem in that there was a high risk that the tube would peel off from the inner surface of the tube, and that the lining was unreliable in maintaining its state.

In addition, as a conventional proposal to solve such problems, a shape-retaining synthetic resin pipe with an outer diameter smaller than the inner diameter of the pipe to be lined was used as the lining pipe, and this was inserted into the pipe to be lined. The lining method (Japanese Unexamined Patent Publication No. 162221/1983) involves expanding the tube by passing a tube expansion plug through the inner surface of the target tube while heating and softening it from the inside. A synthetic resin tube that also has shape retention properties but has an outer diameter that corresponds to the inner diameter of the target tube was used as the tube body, and the cross-sectional form was changed to reduce the outer diameter. A lining construction method has been proposed in which the tube is inserted into the pipe and then heated and pressurized from the inner side to restore the original shape, thereby making it line the inner surface of the target pipe (Japanese Patent Laid-Open No. 63-203316 No.) has been proposed.

However, in the case of the construction method according to the above-mentioned prior proposal, there is no problem if the pipe to be lined is relatively short and straight with no bends, but if the pipe to be lined is long and has no bends, there is no problem. If the lining tube has a section, the insertion of the lining tube may not proceed smoothly, making the insertion work difficult and even impossible, or forcing the lining tube to be inserted. When towed, the tube body may break due to strong sliding contact with the inner surface of the target tube, or even suffer deep abrasions even if it does not result in a tear.
This has caused problems such as tears and cracks occurring during expansion or restoration of the lining tube.

This invention was made with the aim of further solving such problems.

Means for Solving the Problems This invention uses a shape-retaining thermoplastic synthetic resin pipe as the lining pipe as in the conventional proposed construction method, but it has a plurality of protrusions along the axial direction on the outer circumferential surface. By using a material with stripes, it is possible to easily insert the tube into the curved portion of the pipe to be lined during the pulling operation in the heat-softened state (in addition to the above-mentioned heat-softening and post-insertion The tube expansion operation can be easily performed by introducing high temperature fluid into the lining tube.

That is, in this invention, the lining tube to be lined on the inner surface of the target tube is made of a thermoplastic resin tube having an apparent outer diameter smaller than the inner diameter of the target tube, and is continuous in the axial direction on at least a part of the outer circumferential surface. Using a shape-retaining tube in which a plurality of convex stripes are formed as a group of knurled convex stripes, the tube is pulled from one end while being heated and softened by introducing high-temperature fluid into the interior of the tube. A method for lining the inner surface of a pipe, which is characterized by inserting the high-temperature fluid into the pipe, increasing the pressure of the high-temperature fluid to expand the pipe and bringing it into close contact with the inner surface of the target pipe, and then cooling and solidifying the pipe, and the above-mentioned structure used in the method. The main topic is lining tubes.

The types of pipes that require 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, and exhaust pipes, and storage pipes such as electrical wiring, such as metal pipes and fume pipes. Examples include pipes, asbestos pipes, synthetic resin pipes, etc.

The lining tube to be lined on 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 is a so-called hard material that has sufficient shape retention at room temperature. A synthetic resin tube is used.

The tube body is usually formed by extrusion molding, and the apparent outer diameter (the diameter of the circumscribed circle connecting the tips of the convex strips) is made smaller in the range of 95 to 60% than the inner diameter of the target tube. The one given is used. If the outer diameter exceeds 95% of the inner diameter of the target pipe, it will be difficult to insert it into the target pipe, and if the outer diameter is less than 60%, it will be difficult to insert it into the target pipe when expanded in the radial direction after insertion into the existing target pipe. , there is a risk that a significant thickness deviation may occur on the peripheral wall or cracks may occur in the thinned portion. Most preferably, the apparent outer diameter of the tube is about 90 to 70% of the inner diameter of the target tube. Also,
The wall thickness of the tube body is set in advance to be slightly thicker than that so as to ensure the necessary wall thickness when the tube body is finally lined on the inner surface of the target tube. Normally, the required wall thickness after lining is in the range of about 1 to 10 MR,
It is determined as appropriate depending on the purpose, diameter, expansion rate, etc. of the target pipe.

Furthermore, the lining tube is one in which a plurality of protrusions, such as a triangular trapezoidal cross-section, which are continuous in the axial direction, are integrally formed as a group of knurled protrusions on at least a portion of its outer peripheral surface. This is mainly to reduce the frictional resistance caused by sliding contact with the inner surface of the target tube when inserting the tube, and to serve as a guide to facilitate the insertion operation.It also protects the tube surface from deep scratches and tears. This is to prevent the occurrence of Therefore, the group of protrusions may be formed on the entire outer circumferential surface of the tube, but in order to minimize the contact area with the target tube during insertion and reduce frictional resistance as much as possible, It is desirable to separate the strips at a plurality of locations in the circumferential direction and arrange them at equal intervals. For example, it is generally and preferable to arrange about 4 to 10 strips at equal intervals on the outer peripheral surface of the tube.

In addition to using the tube with a circular cross section, the tube with the protruding stripes may be extruded and then heated and softened again to transform it into a flat cross section for convenience in storage or transportation. In this state, the material may be rolled up on a winding device and provided.

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, thereby heating and softening the tube from the inner surface. Then, while maintaining this softened state, it is pulled into the target tube by a pulling means such as a wire connected to one end, and the lining tubes are inserted across the entire length of the corrugated tube.

At this time, the tip of the protruding strip group comes into contact with the inner surface of the target tube, thereby improving the insertability into the target tube. Therefore, it is possible to smoothly insert the tube body even in a curved portion of the target tube.

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, by this tube expansion operation, the outer surface of the tube is brought into close contact with the inner surface of the target tube, and then the fluid introduced 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.

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

As the knee lining tube (1), the above-mentioned target tube (
A) A thermoplastic synthetic resin tube with an apparent outer diameter (ρ2) smaller than the inner diameter (Ω1) in the range of 95 to 60%, with multiple convex strips (2a) having a substantially triangular cross section. A group of protrusions (2) with a predetermined width formed in a knurled state with a zigzag cross section.
are arranged in six rows at predetermined intervals on the outer peripheral surface. The tube (1) is of a type generally called a hard tube, which is made by extruding polyvinyl chloride resin together with the convex strips (2) to have a circular cross section, and has sufficient shape retention at room temperature. It is.

For lining, first, the tube (1) is heated from the inner side to a temperature slightly exceeding the softening temperature of the resin of the tube, for example 80 to 80℃ in the case of vinyl chloride, by introducing high temperature fluid such as steam from one end. It is heated to a temperature of about 95°C.

Therefore, the tube (1) is softened by this heating. Therefore, lining should be applied by pulling the tube body (1) with a cable (4) such as a wire or rope connected to one end of the tube body (1) via a connecting fitting (3) while maintaining this heated and softened state. Pull it into the target tube (A) and insert it over its entire length. During this insertion process, the tube (1)
In order to maintain the softened state of the pipe, the connecting fitting (3) attached to one end of the pipe should have a through hole (5), or the other end should have a through hole that communicates with the outside air. It is necessary to maintain the flow of the high temperature fluid (G) introduced from the inside of the tube. During such an insertion operation, the tube body (1) is inserted into the inner surface of the target tube (A), especially at the bent portion (At
) (A2) The outer peripheral surface is in sliding contact with the inner surface of the target tube (A2), but since the sliding property is improved by the protrusion group (2) and guided by it, the tube body (1) moves relatively easily inside the target tube (A). It moves and inserts smoothly.

When the insertion of the tube body (1) is completed, as shown in Fig. 3, the distal end of the tube is expanded in advance, and a stopper (6) is attached to the expanded end, or one end is closed by any other method. Closed tightly. Then, the pressure of the high-temperature fluid (G) supplied from the fluid supply cap (7) at the other end is increased to increase the internal pressure, thereby expanding the tube body (1) in the radial direction, and the target tube (A
). The pressure applied to this is approximately 0.
, 4-2. It is assumed to be 0Ky/cn+.

After that, remove the frame (6) and replace the fluid supply cap (7).
By supplying low-temperature fluid such as cooling air from the tube body (1), the tube body (1) is cooled and solidified, and the excess portions at both tube ends are cut off to complete the desired lining.

In practice, such lining construction methods are often carried out not only for short pipes but also for long pipes exceeding 10 m and 20 to 30 TrL. Handling a long lining tube corresponding to such a long target tube as a straight tube often involves great difficulties in terms of transportation and storage. Therefore, in such a case, the tube body (1) is manufactured with a slightly flat cross section, rolled up using a winding device, transported to the site, and heated and softened in that state. It is desirable that the tube be inserted into the target tube and restored to its original circular shape when the tube is inflated.

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

This tubular body (11) is provided with a large number of protrusions (2a) over its entire outer peripheral surface, and a large number of reinforcing threads (8) made of tensile fibers are arranged at predetermined intervals inside the peripheral wall. It was buried in

The reinforcing yarn (8) may be any material as long as it has tensile properties and a certain degree of heat resistance, such as various synthetic fibers,
Those made of natural fibers or inorganic fibers are used. In the case of a pipe body (11) in which this reinforcing thread (8) is embedded, the tensile strength of the pipe body due to heat softening is compensated for when inserted into the target pipe (A), and harmful elongation is prevented from occurring in the pipe body. It is possible to improve the ease of insertion into a long-span target pipe or a target pipe that has a curved part.

Effects of the Invention In this invention, the lining tube is heated and softened by introducing high-temperature fluid into it, and then towed and inserted into the target tube, and the tube has relatively free flexibility. In addition to having a group of protrusions on its outer peripheral surface,
The group of protrusions comes into contact with the inner surface of the target tube to reduce frictional resistance and at the same time perform a guiding action, allowing smooth insertion into the target tube. In particular, even if the target pipe has a bend, it can be inserted smoothly along the pipe path without any trouble. In addition, after this insertion, the pressure of the heated fluid is increased to expand the softened lining pipe body, and after bringing it into close contact with the inner surface of the target pipe, it is cooled and solidified, so even if the target pipe is a curved pipe or a different diameter pipe. Or, even if there are some unevenness or steps on the inner surface, the desired lining can be applied without any problem.

[Brief explanation of the drawing]

Figure 1 is a schematic explanatory diagram showing the process of inserting a lining tube into a target pipe that has a bent portion, Figure 2 is a perspective view of the lining tube, and Figure 3 shows the tube being inflated and brought into close contact with the target pipe. FIG. 4 is a sectional view of the pipe line after lining is applied, and FIG. 5 is a perspective view showing a modification of the lining pipe. (A)...Target pipe, (1)...Lining pipe,
(2)... Convex ridge group, (2a)... Convex ridge, (3)...
- Connecting fittings, (4)... Towing cable, (5)... Through hole, (6)... Plug, (G)... High temperature fluid. that's all

Claims (3)

[Claims] (1) The lining tube to be lined on the inner surface of the target tube is made of a thermoplastic resin tube with an apparent outer diameter smaller than the inner diameter of the target tube, and has multiple stripes continuous in the axial direction on at least a portion of the outer circumferential surface. Using a shape-retaining tube in which ridges are formed as a group of knurled ridges, the tube is heated and softened by introducing high-temperature fluid into the interior, and is pulled from one end and inserted into the target tube. Then, the pressure of the high-temperature fluid is increased to expand the pipe body so that it comes into close contact with the inner surface of the target pipe, and then the pipe body is cooled and solidified. (2) A lining pipe that is inserted into the target pipe and then expanded to bring it into close contact with the inner surface of the target pipe, which is made of a thermoplastic resin pipe with an apparent outer diameter smaller than the inner diameter of the target pipe, and at least part of the outer peripheral surface A pipe body for inner lining of a pipe, characterized in that a plurality of protrusions continuous in the axial direction are formed as a group of knurled protrusions on the inner surface of a pipe. (3) The pipe body for inner lining of a pipe according to claim (2), wherein the group of protrusions is formed at a plurality of locations at equal intervals in the circumferential direction of the pipe body.