JPH11325317A - Polyolefin-based liner pipe and its construction method - Google Patents

Abstract

(57) [Problem] To provide a polyolefin liner pipe that can be easily and simply inserted into a bent pipe with a simple device configuration. SOLUTION: A string 2 made of a heat-resistant material is provided on the outer periphery of a polyolefin resin tube 1 deformed so as to have a U-shaped cross section.
Is spirally wound, and the polyolefin-based liner pipe, which is partially fixed, is heated and inserted into the existing pipe 5, then the partial fixing is released, and the tightening force of the spiral cord 2 is released. And the polyolefin-based liner pipe 1 is
Within the tube to restore it to its original shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin liner pipe and a method for constructing the same.

[0002]

2. Description of the Related Art As a method of repairing or renewing an existing pipe while keeping the existing pipe as it is, a thermoplastic resin pipe is inserted into the existing pipe, expanded and restored by heating and applying internal pressure, and resin is applied to the inner surface of the old pipe. A method of forming a liner has been proposed and is being widely implemented (for example, Japanese Patent Laid-Open No. 1-2958).
No. 28).

When repairing or renewing a pipe by the above-mentioned method, a polyolefin resin pipe is mainly used as a liner pipe. By utilizing the shape-memory property of this resin, a once formed pipe is flattened and heated. It is inserted into the existing pipe while being softened, pressurized with a pressurized medium such as air, restored to a tubular shape, and brought into close contact with the inner surface of the existing pipe.

However, in the above-described method, the liner pipe starts restoring and expanding to some extent immediately after heating, so that the liner pipe comes into contact with the inner surface of the bent portion of the pipeline, and it becomes very difficult to insert the liner pipe further due to friction. There are problems such as abnormal elongation, damage, or tensile rupture when pulling.

[0005] On the other hand, in an urban environment, a pipe is often bent complicatedly due to a congested underground structure, so that there has been a problem that the above-mentioned problem causes a very poor work efficiency.

In order to solve such a problem, a flattened polyolefin-based liner pipe is covered with a heat-resistant tube, inserted into an existing pipe, and then the temperature is raised while the heat-resistant tube is pulled out to restore the pipe to its original shape. That (Japanese
No.-47731) or a polyolefin liner pipe covered with a film tube having low heat resistance, inserted into an existing pipe, and then heated to melt, break or expand the film tube, thereby expanding the polyolefin liner pipe. (See Japanese Patent Laid-Open No. 7-7728).
No. 9) has been proposed.

[0007]

However, in the former method, when the film tube is pulled out, it is necessary to interlock the expansion jig, the operation procedure is complicated, and a heating water supply device for expansion is required. There is a problem that implementation is difficult, for example, the device configuration is complicated.

In the latter, a device for further reducing the diameter of the flattened polyolefin-based liner pipe is prepared at the construction site, and the coating of the film tube is performed at the construction site. There was a problem that handling was troublesome.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to make it possible to insert a polyolefin-based liner pipe into a bent pipe easily and with a simple device configuration.

[0010]

In the polyolefin liner pipe according to the first aspect, a cord made of a heat-resistant material is spirally wound around the outer periphery of a polyolefin resin pipe deformed to have a U-shaped cross section. It is partially fixed.

According to this polyolefin liner pipe, the liner pipe can be easily inserted into the existing pipe without being deformed by the helically wound cord even if heated at the construction site. If the tightening force is released by loosening, cutting or pulling out the cord body wound in a shape, the liner pipe is restored to a circular cross section, so that the existing pipe can be easily repaired or renewed.

According to a second aspect of the present invention, there is provided a method for constructing a polyolefin liner pipe, wherein the polyolefin liner pipe is heated and inserted into an existing pipe, and then a partial fastening is released. To restore the polyolefin-based liner pipe to the original pipe shape within the existing pipe.

According to this method, when a polyolefin-based liner pipe is inserted into an existing pipe, it is only necessary to prepare a heating device, so that preparation for construction is greatly simplified, and the pipe is restored to a sectional shape. In this case, since it is only necessary to release the tightening force of the helical cord, the means for restoring deformation is also simplified.

[0014]

Next, an embodiment of the present invention will be described. FIG. 1 is a perspective view of a polyolefin-based liner pipe according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 1 denotes a polyolefin-based liner pipe, which is a U-shaped polyolefin-based liner pipe extruded into a circular cross-section and having a small-diameter cross-section.

A wire 2 is spirally wound around the outer periphery of the polyolefin-based liner pipe 1, and an adhesive tape 3 is wound around a key so that the position of the wire 2 is not shifted, and the wire 2 is temporarily fixed.

In this state, the polyolefin-based liner pipe 1 is wound and transported, for example, on a drum reel 4 (FIG. 2). Therefore, according to the polyolefin-based liner pipe 1 of the first embodiment, it can be formed into a small-diameter cross section at the factory production stage, and can be heated as it is at the construction site and inserted into the existing pipe, so that the construction is very easy. Become.

In the first embodiment, a wire or the like may be used instead of the wire 2, and a heat-resistant rope or yarn made of a natural or synthetic resin may be used.

Further, as a means for temporarily fixing these cords, they may be partially fixed with an adhesive tape, or may be spot-bonded with an adhesive having low heat resistance. Second Embodiment Next, a description will be given of a construction method of inserting the wire 2 into the existing pipe by using the polyolefin-based liner pipe 1 in which the wire 2 is temporarily fixed with an adhesive tape having low heat resistance.

FIG. 2 is an explanatory view of the above construction method. First, both ends 5a of the existing pipe 5 to be repaired or renewed,
5b, a tow wire rope 6 is drawn from one end 5a to the other end 5b, and the polyolefin liner pipe 1 is cut.
Is closed.

The start end 1a of the liner pipe 1 is sealed with a plug jig 1b as shown in FIG. 4A or bent as shown in FIG. It is stopped.

A boiler 7 is attached to the drum 4, and high-temperature steam generated by the boiler 7 is supplied into the drum 4 or the liner pipe 1 through a pipe 8, and the liner pipe 1 is softened by the heating.

After the softened state, as shown in FIG. 3, the tow wire rope 6 is pulled by the winch 9 at one end, and the polyolefin-based liner pipe 1 is drawn into the existing pipe 5.

At this time, since the periphery of the polyolefin-based liner pipe 1 is tightened by the wire 2, it does not deform even when heated to a high temperature.
Even if there is c, it can be easily drawn through.

Next, if high-temperature and high-pressure steam is supplied into the polyolefin-based liner pipe 1, the adhesive tapes 3... 3 are thermally degraded due to high temperature and cut or melt, and the temporary fixing effect is lost.

At this point, if the restraint such as the locked state at the pipe end of the wire 2 is released, the wire 2 is loosened according to the shape restoration of the polyolefin-based liner pipe 1, and the polyolefin-based liner pipe 1 is freely restored and deformed. The liner pipe 1 is in close contact with the inner surface of the existing pipe 10 as shown in FIG.

Therefore, according to the second embodiment, the polyolefin liner pipe 1 helically wound and fixed with the wire 2 may be inserted into the existing pipe while heating and softening, and then heated to the shape restoration temperature. Very easy. Embodiment 3 Next, a construction method of inserting the wire 2 into the existing pipe using the polyolefin-based liner pipe 1 in which the wire 2 is temporarily fixed with a heat-resistant adhesive tape will be described.

First, as in the second embodiment, the polyolefin-based liner pipe 1 is connected to the tow wire rope 6, and the liner pipe 1 is heated and softened by high-temperature steam. In the case of the third embodiment, the adhesive tape 3 does not deteriorate and break due to heat.
And cut.

The liner pipe 1 is drawn into the existing pipe 5 by the tow wire rope 6, but the liner pipe 1 is drawn into the existing pipe 5 without restoring deformation due to the winding force of the wire 2. go.

After the liner pipe 1 has been drawn into the existing pipe 5, the wire 2 is connected before the liner pipe 1 is completely restored and expanded.
Is released, and the wire 2 is pulled out of the existing pipe 5 through the gap remaining between the inner surface of the existing pipe 5 and the outer surface of the liner pipe 1.

Thereafter, high-temperature and high-pressure steam is supplied into the liner pipe 1, and the polyolefin-based liner pipe 1 is restored and expanded by the cooperation of the shape restoring force and the internal pressure, and is brought into close contact with the inner surface of the existing pipe 5.

According to the third embodiment, the wire 2 wound spirally is pulled out immediately before the liner pipe 1 is restored and deformed, so that the liner pipe 1 is smoothly restored and deformed.

[0033]

According to the present invention, as described above, the polyolefin liner pipe does not recover and deform even when heated while the tightened state of the cord body is not released, so that it can be inserted into the existing pipe very easily. Even if there is a bent portion in the pipe, smooth insertion becomes possible.

Further, since the restoration deformation can be achieved by releasing the tightening force of the cord, the restoration deformation time can be set to a desired time, which has an effect of facilitating construction.

[Brief description of the drawings]

FIG. 1 is a perspective view of a polyolefin-based liner pipe according to Embodiment 1 of the present invention.

FIG. 2 is an explanatory view of a method for constructing a polyolefin-based liner pipe according to the present invention.

FIG. 3 is an explanatory view of a method for constructing a polyolefin-based liner pipe of the present invention.

FIGS. 4A and 4B are perspective views showing a state where the liner pipe is locked at the start end, wherein FIG. 4A shows a case where a stopper jig is used, and FIG.

FIG. 5 is a sectional view showing an installed state of a liner pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polyolefin liner pipe 2 String body 3 Adhesive tape for temporary fixing 5 Existing pipe 6 Tow wire rope 7 Boiler

Claims (2)

[Claims] 1. A polyolefin-based liner pipe in which a cord made of a heat-resistant material is spirally wound around a periphery of a polyolefin-based resin pipe deformed so as to have a U-shaped cross-section and partially fixed. 2. The polyolefin-based liner pipe according to claim 1, wherein the polyolefin-based liner pipe is heated and inserted into an existing pipe, and then partial fastening is released, and the tightening force of the helical cord is released to release the polyolefin-based liner pipe. A method for constructing a polyolefin liner pipe that restores the liner pipe to its original shape within the existing pipe.