JPH06344341A - Removing method of plastic pipe innerly lined in pipeline - Google Patents

Abstract

PURPOSE:To easily pull out with small force by a method wherein the frictional resistance between plastic pipe and pipeline is reduced by separating the plastic pipe from the pipeline and reducing the crosssectional shape of the pipe by evacuating. CONSTITUTION:By evacuating the plastic pipe 2, which is innerly lined and both the ends of which are in airtightly sealed, the plastic pipe 2 is separated from the inner surface of pipeline 1 and, at the same time, the crosssectional shape of the pipe is deformed and reduced. After that, the plastic pipe 2 is pulled out of the pipeline 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to repair or reinforce pipes mainly buried in the ground such as gas pipes, water pipes, sewer pipes, and laying pipes for communication lines and power lines. If you insert a plastic pipe inside and line it, the plastic pipe will deteriorate and
When the plastic pipe is crushed for some reason and its function as a pipeline is impaired, it relates to a method for removing the old plastic pipe from the pipeline when relining the pipeline. is there.

[0002]

2. Description of the Related Art Conventionally, when removing a plastic pipe in a pipeline as described above, the plastic pipe is gradually cut off and removed, or the plastic pipe is heated and softened to pull it from the pipeline. It was being pulled out.

[0003]

However, in the method of cutting and removing the plastic pipe, it is not easy to cut the lining material in the long pipe line, it takes a long time, and the pipe line itself is removed. Also often hurt.

Further, in the method of pulling out the plastic pipe, even if the plastic pipe is heated and softened, it is not easy to pull out what is bulging along the inner surface of the pipeline, and it is extremely large. It takes power. Further, if the pulling force becomes excessive, the plastic pipe may be broken, and it is more difficult to remove the plastic pipe remaining in the pipeline.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for easily pulling out a plastic pipe lined with a pipe line from the inside of the pipe line with a small force. .

[0006]

The first aspect of the present invention is to airtightly seal both ends of a plastic pipe lined in a pipe, depressurize the inside of the plastic pipe, and connect the plastic pipe to the pipe. It is characterized in that the plastic pipe is pulled out from the inside of the duct after the peeling from the inner surface and the cross-sectional shape is reduced and deformed.

The second invention is the same as the first invention,
The plastic pipe lined in the pipeline is heated over its entire length, and the plastic pipe is depressurized while the plastic pipe is softened.

A third aspect of the invention is to fill a plastic pipe lined in a pipe line with pressurized steam and heat the pipe.
Next, both ends of the plastic pipe are hermetically sealed, the plastic pipe is depressurized by the condensation of the pressurized steam to separate the plastic pipe from the inner surface of the pipe, and the cross-sectional shape is reduced and deformed. It is characterized by pulling out a plastic pipe from the.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a step of reducing the cross-sectional shape of a plastic pipe in a pipe lined by the first invention. FIG. 1A shows a lined pipe, 1 is a pipe line, and 2 is a plastic pipe inserted along the inner surface of the pipe line 1. FIG. 3 is an enlarged cross-sectional view of this lined pipe.

Then, both ends 3 of the plastic pipe 2 are peeled off from the inner surface of the conduit 1, and the ends 3 are crushed and fused and hermetically sealed.
The tip of the hose 4 connected to the vacuum pump is connected. This state is shown in FIG.

When the pressure inside the plastic pipe 2 is reduced by the decompression pump through the hose 4, the plastic pipe 2 is crushed by the external pressure as shown in FIGS. 1 (c) and 4, and the cross-sectional shape is reduced. In this state, by pulling the plastic pipe 2 from one side, the plastic pipe 2 can be easily pulled out from the pipe line 1.

Since the plastic pipe 2 is usually made of a hard thermoplastic resin such as polyethylene or polyvinyl chloride and has a considerable rigidity, it may be difficult to be crushed only by depressurizing the inside thereof. In such a case, the second invention is applied to the plastic pipe 2 in advance.
It is preferable to soften the plastic pipe 2 by feeding the heating fluid into the inside or heating the fluid by feeding the heating fluid between the plastic pipe 2 and the conduit 1 while reducing the pressure.

FIG. 2 shows a state in which the third invention is carried out, in which pressurized steam is fed from a hose 5 into a plastic pipe 2 lined with a pipe 1 in FIG. The pipe 2 is heated and softened, and the plastic pipe 2 is filled with pressurized steam.

The plastic pipe 2 is sufficiently heated,
Further, when the pressurized steam has filled the plastic pipe 2 sufficiently, both ends 3 of the plastic pipe 2 are peeled off from the conduit 1 and hermetically sealed as shown in FIG.

Then, the closed plastic pipe 2
Inside, the pressurized steam condenses as it cools, and
As shown in (c) and FIG. 4, it is crushed by the atmospheric pressure to reduce the sectional shape. By pulling the plastic pipe 2 from one side in this state, it can be easily pulled out from the pipe line 1.

The following experiment was conducted to confirm the effect of the present invention.

A polyethylene pipe having an outer diameter of about 150 mm and a thickness of 5 mm is inserted into a steel pipe having an inner diameter of 150 mm and a length of 30 m, which includes four 45 ° bends, and the polyethylene pipe is expanded by heating and pressurizing it. They were lined together and cooled to room temperature.

Next, live steam was blown into the polyethylene pipe to heat it, and a winch was connected to one end of the polyethylene pipe to pull it, so that the polyethylene pipe was pulled out from the steel pipe. I couldn't.

Next, seal both ends of the polyethylene pipe,
When the inside of the polyethylene pipe was decompressed from one end with a decompression pump, the polyethylene pipe was crushed into a U-shaped cross section in the steel pipe, and when this was pulled out, it could be pulled out with a force of about 240 kg.

When the same polyethylene pipe is lined with the same steel pipe and live steam is blown into the polyethylene pipe to heat it and the both ends of the polyethylene pipe are sealed after the raw steam is released from the end of the polyethylene pipe. ,
In about 10 minutes, the polyethylene pipe was crushed in the steel pipe into a substantially concave cross section. When this polyethylene pipe was pulled out from the steel pipe, it could be pulled out with a force of about 350 kg.

[0021]

According to the present invention, since the plastic pipe 2 lined along the inner surface of the conduit 1 is crushed by being decompressed and the cross-sectional shape is reduced,
The frictional resistance between the plastic pipe 2 and the conduit 1 is greatly reduced.

Therefore, even in the case where the plastic pipe 2 cannot be drawn out by heating and softening it, the plastic pipe 2 can be easily drawn out with a smaller force by reducing the sectional shape of the plastic pipe 2, and the conduit 1 Even if there is a bend such as a bend, it can be pulled out.

Further, according to the present invention, since the plastic pipe 2 can be pulled out at once in the entire length thereof,
The plastic pipe 2 can be removed in a short time, it is not necessary to cut the plastic pipe 2 into small pieces, and there is no risk of damaging the conduit 1.

Furthermore, according to the third aspect of the invention, it is sufficient to have a facility for supplying pressurized steam, and the decompression pump as in the first aspect of the invention is not required. Therefore, the plastic pipe 2 can be pulled out by a simpler operation. it can.

[Brief description of drawings]

FIG. 1 is a central longitudinal sectional view showing a step of removing a plastic pipe 2 from a pipeline 1 according to the first invention.

FIG. 2 is a central longitudinal sectional view showing a step of removing a plastic pipe 2 from a pipeline 1 according to a second invention.

FIG. 3 Pipe line 1 lined with a plastic pipe 2
Cross section of

FIG. 4 is a cross-sectional view showing a state in which the plastic pipe 2 has a reduced cross-sectional shape in the pipe line 1.

[Explanation of symbols]

 1 pipeline 2 plastic pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Takebe 1-4-1, Kishibekita, Suita City, Osaka Prefecture Dorif Dormitory (72) Inventor Takuji Sorikawa 3-7-1 Ichiriyama, Otsu City, Shiga Prefecture (72) ) Inventor Hitoshi Saito 1-24-24 Kaminita, Toyonaka-shi, Osaka E-604

Claims (3)

[Claims] 1. A plastic pipe (2) lined in a pipe line (1) is hermetically sealed at both ends thereof, and the inside of the plastic pipe (2) is decompressed so that the plastic pipe (2) is connected to the pipe line (1). ) A method for removing a plastic pipe lined in a pipeline, characterized in that the plastic pipe (2) is pulled out from the pipeline (1) after it is peeled from the inner surface and the cross-sectional shape is reduced and deformed. 2. A plastic pipe (2) lined in a pipe line (1) is heated over its entire length to reduce the pressure inside the plastic pipe (2) while the plastic pipe (2) is softened. The method for removing a plastic pipe lined in a pipeline according to claim 1, characterized in that 3. A plastic pipe (2) lined in a pipe line (1) is filled with pressurized steam and heated, and then both ends of the plastic pipe (2) are hermetically sealed to remove the pressurized steam. The plastic pipe (2) is decompressed by condensation to separate the plastic pipe (2) from the inner surface of the pipeline (1), and the cross-sectional shape is reduced and deformed, and then the plastic pipe (2) is removed from the pipeline (1). ) Is removed, a method for removing a plastic pipe lined in a pipeline