JPH0839672A - Renewal pipe for lining existing pipe and lining method for existing pipe using it - Google Patents

Abstract

(57) [Summary] [Purpose] A renewal pipe for lining an existing pipe and a lining method using the same that allows uniform diameter expansion, has a smooth inner peripheral surface even after diameter expansion, and has good adhesion to the existing pipe. provide. In this renewal pipe A, a resin pipe 1 made of a thermoplastic resin is covered with an outer layer 2 having at least one resin foam layer made of a thermoplastic resin. After inserting A into the pipeline of the existing pipe 3, sealing both ends thereof, pressurizing a heating fluid into the inside of the renewal pipe A to expand the diameter of the renewal pipe A while heating and softening the renewal pipe A. This is a construction method in which the inner surface of 3 is closely attached.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a renewal pipe for lining an existing pipe and a method for lining an existing pipe using the renewal pipe.

[0002]

2. Description of the Related Art As a method of repairing existing gas pipes and water supply / drainage pipes, for example, a renewal pipe made of a thermoplastic resin such as vinyl chloride or polyethylene is inserted into the existing pipes, and then the renewal is performed. Developed a liner construction method in which both ends of the pipe are sealed and steam at a predetermined temperature (predetermined pressure) is press-fitted inside to heat and soften the renewal pipe and expand the diameter to adhere it to the inner surface of the existing pipe. (See Japanese Patent Laid-Open No. 1-295828).

[0003]

However, in the conventional lining method, the following problems may occur. That is, first, when steam is fed into the renewal tube and the renewal tube is heated, the renewal tube is not uniformly heated to the desired temperature as a whole, for example, with the inner peripheral surface and the outer peripheral surface. In some cases, a temperature difference may occur between the part that contacts the existing pipe and the part that does not contact the existing pipe. Therefore, when there is a portion below the softening point of the resin that constitutes the renewal pipe, or when the temperature is above the softening point but the temperature varies depending on the location, the steam is pressurized to expand the diameter. When the operation is started, the portion where the softening is relatively advanced is preferentially expanded in diameter, and uniform expansion of diameter of the entire renewal tube becomes difficult to occur. In extreme cases, part of the diameter may increase excessively.

In addition, when rust lumps or irregularities are present on the inner peripheral surface of the existing pipe, the outer peripheral surface of the renewal pipe extends over the entire inner peripheral surface of the existing pipe even after the expansion of the diameter. There is a case where they do not adhere to each other, or an uneven pattern corresponding to the above-mentioned unevenness is projected on the inner peripheral surface of the thinned renewal pipe. If the inner peripheral surface of the renewal pipe is in such a state, resistance may increase when a predetermined fluid is flowed into the renewed pipe, and smooth flow may be hindered.

Further, the renewal pipe may contract during cooling of the renewal pipe after completion of the diameter expansion. At that time, a minute gap may occur between the inner peripheral surface of the existing pipe and the renewal pipe. The effect of renewal may be diminished. It is an object of the present invention to provide an existing pipe lining renewal pipe that can solve the above-mentioned problems found in the conventional lining process and an existing pipe lining process using the renewal pipe.

[0006]

In order to achieve the above object, in the present invention, a resin tube made of a thermoplastic resin is covered with an outer layer having at least one resin foam layer made of the thermoplastic resin. A renewal pipe for lining an existing pipe is provided. Further, after inserting the above-mentioned renewal pipe into the pipeline of the existing pipe, by expanding the diameter of the renewal pipe while heating and softening it, the renewal pipe is brought into close contact with the inner surface of the existing pipe. Lining method is provided.

[0007]

In the renewal pipe of the present invention, since the outer layer enclosing the resin pipe contains at least one resin foam layer, this outer layer has a good heat insulating property. Therefore, the resin pipe is kept warm by this outer layer, and for example, even when the lower part of the renewal pipe is in contact with the existing low temperature pipe, the resin pipe is not easily affected by the temperature of the existing pipe, and the temperature of the entire resin pipe is Make more uniform as a whole. Therefore, the diameter can be expanded more uniformly.

Further, since the outer layer is also highly elastic, when the outer peripheral surface of the renewal pipe comes into contact with the irregularities of the existing inner peripheral surface of the existing pipe due to the diameter expansion, the irregularities are absorbed by the outer layer.
The inner surface of the renewed pipe becomes smooth. Also, in the process in which the renewal pipe adheres to the inner peripheral surface of the existing pipe at the time of diameter expansion, even if there are irregularities on the inner peripheral surface of the existing pipe, the renewal pipe will elastically wrap those irregularities. As the thickness is reduced and the adhesion is improved, the adhesion between the outer layer and the existing pipe is also improved.

In the renewal pipe of claim 2, since the resin foam layer is located at the uppermost layer of the outer layer, the resin foam layer comes into direct contact with the inner peripheral surface of the existing pipe. Therefore, the heat insulation effect and the elasticity effect of the resin foam layer are more effectively exhibited.

[0010]

【Example】

(Embodiment 1) A renewal pipe and a lining method according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the renewal pipe A of the present invention and a state in which the renewal pipe A is inserted into an existing pipe 3. The renewal tube A may be flat.

The renewal pipe A is composed of a resin pipe 1 made of a thermoplastic resin and an outer layer 2 provided so as to cover the outer periphery thereof. The resin pipe 1 may be any as long as it has been conventionally used for lining, and examples thereof include a polyvinyl chloride pipe and a polyethylene pipe.

The outer layer 2 may be composed of only one layer, or may be composed of a plurality of layers. In any case, the constituent resin is a thermoplastic resin, and when it is composed of a plurality of layers. At least one layer is a resin foam layer.
When the resin foam layer is composed of a plurality of layers, it is preferable that the resin foam layer is located on the uppermost layer.

Examples of the resin foam include polyvinyl chloride foam and polyethylene foam. And this resin foam layer has an expansion ratio of 5 to 5
It is preferably 0 times. This is because when the expansion ratio is less than 5 times, the elasticity is poor and the heat insulating property is poor. However, those having a foaming ratio of more than 50 times have low mechanical strength, so that they may be damaged when they come into contact with irregularities on the inner peripheral surface of the existing pipe at the time of inserting the renewal pipe, and the heat insulating effect is also poor. This is because the heat retaining function of the resin pipe 1 is deteriorated.

The renewal pipe A is first inserted into the conduit of the existing pipe 3. At this time, the lower portion of the renewal pipe A comes into contact with the inner peripheral surface of the existing pipe 3 at a low temperature as shown in FIG. 1, but due to the heat insulating effect of the outer layer 2 having the resin foam layer, the renewal pipe A is already installed in the resin pipe 1. The influence of the temperature of the tube 3 is less likely to occur. Next, for example, both ends of the renewal pipe A are made into a sealed structure, and a heating fluid such as steam or hot air is inserted into the inside to heat the resin pipe 1. At this time, the amount of heat from the heating fluid is prevented from escaping to the existing pipe 3 due to the heat insulating effect of the outer layer 2 and is effectively consumed for heating the resin pipe 1, so that the resin pipe 1 as a whole is uniform. Temperature

When the temperature of the resin tube 1 reaches or exceeds the softening point of its constituent resin, the pressure of steam or hot air is increased to expand the diameter of the resin tube 1. Since the temperature of the resin pipe 1 is more uniform as a whole, the diameter of the entire resin pipe 1 is expanded more uniformly and the wall thickness is reduced, and accordingly, the outer layer 2 is also thinned and starts to come into contact with the inner peripheral surface of the existing pipe 3.

At this time, even if there are convex portions 3a on the inner peripheral surface of the existing pipe 3, the elastic outer layer 2 has these convex portions 3a.
Is gradually wrapped around and compressed, and in the process absorbs irregularities into itself. As a result, as shown in FIG. 2, no unevenness appears on the inner peripheral surface of the thinned resin pipe 1 ′ after the diameter expansion, and the outer layer 2 ′ of the renewed pipe A ′ after the diameter expansion is inside the existing pipe 3. It is lined in close contact with the peripheral surface.

[0017]

As is apparent from the above description, the renewal pipe of the present invention is provided with the outer layer having the resin foam layer having heat insulation and elasticity on the outer side of the resin pipe, so that the renewal pipe is expanded. The resin pipe to be sized can be kept warm, and the diameter can be uniformly expanded. Moreover, even if there are irregularities on the inner peripheral surface of the existing pipe, the outer layer with high elasticity absorbs these irregularities and the inner peripheral surface of the renewal pipe becomes smooth, and the renewal pipe after expansion and the existing pipe Adhesion is also improved.

In the case of the renewal pipe according to the second aspect, since the resin foam layer is located at the uppermost layer of the outer layer, the heat insulation and elasticity of the resin foam layer are more effectively exhibited.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which a renewal pipe of the present invention is inserted into an existing pipe having a convex portion on an inner peripheral surface.

FIG. 2 is a cross-sectional view showing a state at the time when the lining is finished by heating and expanding the diameter from the state of FIG.

[Explanation of symbols]

 1 resin pipe 1'resin pipe after diameter expansion 2 outer layer (resin foam layer) 2'outer layer after diameter expansion 3 existing pipe 3a convex portion A renewal pipe A'renewal pipe after diameter expansion

(72) Inventor Yasuo Nakajima 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Kazuo Sadamitsu 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Industrial Co., Ltd. (72) Inventor Jiro Sakado 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (72) Inventor Shintaro Ikeda 347-44 Unomori, Sagamihara City, Kanagawa Prefecture (72) Inventor Toru Fukusato 3-3-7 Fukami Higashi, Yamato-shi, Kanagawa Bonur Fukami A

Claims (3)

[Claims] 1. A resin pipe (1) made of a thermoplastic resin,
An existing pipe lining renewal pipe (A), which is covered with an outer layer (2) having at least one resin foam layer made of a thermoplastic resin. 2. The renewal pipe (A) for an existing pipe lining according to claim 1, wherein the resin foam layer is located at the outermost layer of the outer layer (2). 3. The renewal pipe by inserting the renewal pipe (A) according to claim 1 or 2 into a conduit of an existing pipe (3) and then expanding the diameter of the renewal pipe (A) while heating and softening the renewal pipe (A). (A)
A method of lining an existing pipe, characterized in that the inner surface of the existing pipe (3) is closely attached.