JPH07260042A - Renewal pipe for gas pipe and method for renewing gas pipe using same - Google Patents

Abstract

PURPOSE:To provide a renewal pipe for a gas pipe, which is used for a lining construction method for an existing gas pipe and where gas to be transported cannot be leaked. CONSTITUTION:A renewal pipe A for a gas pipe comprises a resin pipe 1, a hot melt adhesive layer 2 covering the outside of the resin pipe 1, and a gas barrier layer 3 covering the outside of the hot melt adhesive layer 2. The hot melt adhesive layer 2 is brought into not-contact with the resin pipe 1 and/or the gas barrier layer 3, and is inserted into an existing gas pipe, where a diameter of the layer 2 is enlarged for use while being softened with heat.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As a construction method for repairing gas pipes and water supply / drainage pipes buried in the ground, for example, existing pipes have a smaller diameter than that of thermoplastic pipes such as vinyl chloride and polyethylene. Insert a renewal tube made of resin, and then
A liner that seals both ends of the renewal pipe and pressurizes steam of a predetermined temperature (predetermined pressure) into the renewal pipe to heat and soften the renewal pipe and expand its diameter to make it adhere to the inner surface of the existing gas pipe. A construction method has been developed (see JP-A-1-295828).

[0003]

However, when the above-mentioned renewal method is applied to the existing gas pipe, if the gas is transported to the renewed gas pipe for a long period of time, a leak occurs in the existing gas pipe. This may cause a problem that gas leakage occurs intensively from a part. This phenomenon occurs because resins such as vinyl chloride and polyethylene used as materials for renewal tubes generally have high gas permeability. That is, when the gas is transported to the renewed gas pipe, a part of the gas permeates the renewal pipe, and then passes through the minute gap existing between the renewal pipe and the gas pipe, and the leak portion of the existing gas pipe. Because it flows up to.

The present invention can prevent the above-mentioned problems from occurring in the gas pipe renewal pipe used in the lining method, has a low gas permeability, and has excellent adhesion to the inner surface of the gas pipe. Another object of the present invention is to provide a renewal pipe for a gas pipe and a method for renewing a gas pipe using the renewal pipe.

[0005]

In order to achieve the above-mentioned object, in the present invention, a resin pipe, a hot melt adhesive layer encapsulating the outside of the resin pipe, and a hot melt adhesive layer are provided. Consisting of a gas barrier layer enclosing the outside,
There is provided a renewal pipe for a gas pipe, wherein the hot melt adhesive layer is in a non-adhesive state with the resin pipe and / or the gas barrier layer. Further, in the present invention, by inserting the above-mentioned renewal pipe into an existing gas pipe and then sealing both ends thereof, the heating fluid is press-fitted into the renewal pipe to expand the diameter while heating and softening the same. A method of renewing a gas pipe is provided, in which a renewal pipe is lined on the inner surface of the existing gas pipe, and the resin pipe and the gas barrier layer are bonded and integrated with the hot melt adhesive layer. .

[0006]

After the renewal of the existing gas pipe using the renewal pipe of the present invention, the gas barrier layer encapsulating the outside of the resin pipe, which has been softened by heating and expanded in diameter, comes into close contact with the inner surface of the existing gas pipe. At the same time, the hot melt adhesive layer interposed between the resin pipe and the gas barrier layer melts by the heat when the resin pipe is heated and softened, and exerts an adhesive function. Bonded through the melt adhesive layer.

Therefore, when the gas is transported into the renewed gas pipe, that is, into the renewal pipe, even if the gas permeability of the resin pipe constituting the renewal pipe is large, the gas that has permeated the resin pipe has a gas barrier. By the function of the layer, outside the renewal tube,
That is, there is no leakage between the renewal pipe and the gas pipe. Further, in the case of the renewal pipe of the present invention, the hot melt adhesive layer is not adhered to both the resin pipe and the gas barrier layer at the same time in the pre-stage of the renewal work, and the hot melt adhesive layer floats to either one or both. It's ready to go. Therefore, when the resin pipe softens and expands in diameter during the renewal work, the hot melt adhesive layer does not melt in the initial stage, so that the hot melt adhesive layer can float following the expansion of the diameter of the resin pipe. Therefore, for example, even when the gas barrier layer is a metal foil having a small elongation at break, the diameter of the resin pipe can be expanded without damaging the metal foil.

In the renewal pipe of claim 2, since the hot-melt adhesive layer 2 and the gas barrier layer 3 vertically cover the resin pipe 1, when the diameter of the resin pipe 1 is expanded, the expansion is followed. The gas barrier layer 3 is expanded in the circumferential direction, and the load on the gas barrier layer 3 is reduced. for that reason,
Damage to the gas barrier layer 3 is suppressed.

[0009]

【Example】

(Embodiment 1) FIG. 1 is a sectional view showing an example of the renewal pipe of the present invention.
Shown in. The renewal pipe A has a sectional structure in which the outside of the resin pipe 1 is first covered with the hot melt adhesive layer 2, and the outside of the hot melt adhesive layer 2 is covered with the gas barrier layer 3.

The resin pipe 1 may be any as long as it can be softened by heating and expanded in diameter, and examples thereof include a vinyl chloride pipe and a polyethylene pipe used in a conventional lining method. it can. Further, the hot-melt adhesive layer 2 has a lower melting point than the resin constituting the resin pipe 1, is already in a molten state during the process of softening and expanding the diameter of the resin pipe 1, and at the end of the expansion of the diameter of the resin pipe 1. In this case, it is formed of a thin layer of a hot melt adhesive that exhibits good adhesiveness to both the resin tube 1 and the gas barrier layer 3.

For example, when the resin pipe 1 is a polyethylene pipe, the melting point of polyethylene is about 106 to 135 ° C., so that the hot melt adhesive used is 50 to 1
An ethylene-vinyl acetate copolymer, an ethylene-ethyl acetate copolymer, and the like, which melts at 00 ° C and exhibits adhesiveness, are suitable. When the resin pipe 1 is a vinyl chloride pipe, since the melting point of vinyl chloride is about 75 to 80 ° C, the hot melt adhesive to be used is, for example, melted at 50 to 70 ° C to exert an adhesive ability. Ethylene-vinyl acetate copolymer, ethylene-ethyl acetate copolymer, etc. are suitable.

The gas barrier layer 3 has a small gas permeability,
It is made of a flexible or malleable foil or film. Specifically, for example, a metal foil such as an aluminum foil or a lead foil, a film formed by vapor-depositing a metal such as aluminum on one or both sides of a plastic film, or a gas permeability higher than that of the constituent resin of the resin pipe. Examples of the film include plastic films such as polyvinylidene chloride and Eval, which have a small value, and laminated films thereof.

Here, the hot melt adhesive layer 2 is provided so as not to adhere to both the resin pipe 1 and the gas barrier layer 3 at the same time. That is, whether it is in a non-adhesive state between the resin pipe 1 and the gas barrier layer 3 or in a non-adhesive state between the gas barrier layer 3 and the resin pipe 1, Alternatively, neither the resin pipe 1 nor the gas barrier layer 3 is in a non-bonded state.

In such a state, the hot melt adhesive layer 2 melts and exhibits fluidity in the process of expanding the diameter of the resin pipe 1, so that the layers can move freely. Therefore, even if the diameter of the resin pipe 1 is expanded, each layer can follow the diameter expansion of the resin pipe 1. On the other hand, if the resin tube 1, the hot melt adhesive layer 2 and the gas barrier layer 3 are preliminarily adhered to each other, the resin tube 1 is freely expanded between the layers in the process of expanding the diameter. Since it is inadequate, for example, the gas barrier layer 3 is damaged.

When manufacturing the renewal pipe A shown in FIG. 1,
For example, it is preferable that a film which becomes the hot melt adhesive layer 2 and a film which becomes the gas barrier layer 3 are superposed, and the resin pipe 1 is vertically attached and covered by the laminated film with the film of the hot melt adhesive inside. By performing such a vertical coating, when the diameter of the resin pipe 1 is expanded, the gas barrier layer 3 is expanded and expanded in the circumferential direction as indicated by the arrow in the figure, following the expansion. This is because the load on the layer 3 is small and the effect of suppressing the damage is large.

In this case, the width of the stacking margin of the laminated film is
Even when the diameter expansion of the resin pipe 1 is completed, the width is set so that the gas barrier layer 3 can cover the resin pipe after the diameter expansion. (Embodiment 2) FIG. 2 shows a sectional view of an update pipe B of another embodiment.

The renewal pipe B is obtained by enclosing the gas barrier layer 3 of the renewal pipe A shown in FIG. 1 with a protective layer.
In this case, the gas barrier layer 3 and the protective layer 4 are in a non-bonded state. The protective layer may be, for example, a tube made of a thermoplastic resin such as polyethylene, polypropylene or an ethylene-vinyl acetate copolymer, or may be a tube made of the hot melt adhesive described above. .

This protective layer has a function of expanding when the diameter of the resin pipe 1 is expanded and making pressure contact with the inner surface of the existing gas pipe, thereby preventing a gap from being formed between the renewal pipe B and the inner surface of the existing gas pipe. To do. Also, for example, at the time of protection of the renewal tube B before renewal work,
The gas barrier layer 3 has a function of suppressing a situation in which the gas barrier layer 3 is corroded or deteriorated by a corrosive component in the atmosphere. (Embodiment 3) Next, a method 1 for updating an existing gas pipe of the present invention will be described.
An example will be described with reference to FIGS. 3 and 4 in the case of using the above-described update tube B.

First, as shown in FIG. 3, the renewal pipe B is inserted into the existing gas pipe 5. Then, the openings at both ends of the renewal tube B are sealed, and water vapor having a predetermined temperature (predetermined pressure) is injected into the renewal tube B (not shown). The resin pipe 1 of the renewal pipe B is heated and softened, and the hot-melt adhesive layer 2 and the protective layer 4 are also heated and softened. Then, the resin pipe 1 receives the pressure of water vapor and expands in diameter.

Hot melt adhesive layer 2 and gas barrier layer 3
Covers the resin pipe 1 vertically, these layers are expanded in the circumferential direction following the diameter expansion of the resin pipe 1,
Further, the protective layer 5 is expanded. After a lapse of a predetermined time, the outside of the renewal pipe B comes into contact with the inner surface of the existing gas pipe 5 and the diameter expansion of the resin pipe 1 is stopped (FIG. 4).

In the process of expanding the diameter, the resin pipe 1 and the gas barrier layer 3 are bonded and integrated with a hot melt adhesive, and at the same time, the protective layer 5 is pressed against the inner surface of the existing gas pipe 5 and bonded thereto. Thereafter, while maintaining the internal pressure of the resin pipe 1, the steam is replaced with the outside air to cool the whole renewal pipe after the diameter expansion, the resin pipe 1, the hot-melt adhesive and the protective layer 5 are solidified, and then the diameter expansion is performed. The renewal pipe sealing structure is dismantled to release the pressure in the pipe.

[0022]

As is apparent from the above description, in the case of the renewal pipe of the present invention, after the diameter of the renewal pipe is expanded and brought into close contact with the inner surface of the existing gas pipe, the outside of the resin pipe after the diameter expansion is Since the gas barrier layer is integrated by being bonded with a hot melt adhesive, even if the gas permeability of the resin pipe is small and the gas flowing in the pipe permeates through the resin pipe, the gas barrier layer There is no leakage between the renewal pipe and the existing gas pipe.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a renewal tube of the present invention.

FIG. 2 is a cross-sectional view showing another renewal pipe of the present invention.

FIG. 3 is a cross-sectional view showing a state in which the renewal pipe of FIG. 2 is inserted into an existing gas pipe.

FIG. 4 is a cross-sectional view showing a state after completion of lining of the renewal pipe.

[Explanation of symbols]

 1 Resin Pipe 2 Hot Melt Adhesive Layer 3 Gas Barrier Layer 4 Protective Layer 5 Existing Gas Pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kensuke Okamoto 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Kazuo Sadamitsu 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Jiro Sakado 2-6-1, Marunouchi, Chiyoda-ku, Tokyo 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 City, Kanagawa Prefecture Bo Nuru Fukami A

Claims (4)

[Claims] 1. A resin pipe 1 and a hot melt adhesive layer 2 encapsulating the outside of the resin pipe 1.
And a gas barrier layer 3 covering the outside of the hot melt adhesive layer 2, the hot melt adhesive layer 2 being in a non-adhesive state with the resin pipe 1 and / or the gas barrier layer 3. Renewal pipe for gas pipes. 2. The renewal pipe for a gas pipe according to claim 1, wherein the hot melt adhesive layer 2 and the gas barrier layer 3 are vertically attached to the resin pipe 1. 3. The renewal pipe for a gas pipe according to claim 1, further comprising a protective layer 4 provided outside the gas barrier layer 3 to cover the gas barrier layer 3 in a non-adhesive state. 4. The gas pipe renewal pipe according to claim 1 or 2 is inserted into an existing gas pipe, both ends thereof are sealed, and a heating fluid is press-fitted into the inside of the renewal pipe to expand the diameter while heating and softening. Thereby, the renewal pipe is lined on the inner surface of the existing gas pipe, and at least the resin pipe and the gas barrier layer are bonded and integrated with the hot melt adhesive layer to renew the gas pipe. Method.