JP2007132370A - Plastic tube embedding method and protection sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protection sheet which can be enwound around and can be fixed to a plastic tube with ease and further can be cut in a necessary place thereof without scratching the plastic tube even when a saddle joint or the like needs to be connected with the plastic tube and furthermore to provide a plastic tube embedding method by which earth and sand which have been subjected to back-filling is allowed to contact with the plastic tube to thus eliminate gapping between the plastic tube and the earth and sand. <P>SOLUTION: Even if claws of the excavator hit accidentally a water and sewerage tube and a plastic gas tube, when digging the ground using an excavator an impact-resistant protection sheet is schemed which is enwound around the plastic tube so as not to scratch the plastic tube. In this case, the protection sheet 6 has a quadruple-layered structure in which a sheet 7 woven using fibrillated film yarn produced by drawing polypropylene to be unstitched and a cushioning material 8 made from a spunbonded-fabric sheet formed from polypropylene are alternately layered. Then, an adhesive is applied on the rear surface of the protection sheet 6 and then the protection sheet 6 is enwound around a polyethylene tube 11 to then bond both together. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for embedding a plastic pipe in soil, and a protective sheet wound around the plastic pipe in order to enhance the impact resistance of the embedded plastic pipe.

  In recent years, plastic pipes have become widespread as liquid transport pipes, such as water and sewage pipes and gas pipes. Among them, polyethylene pipes are flexible, lightweight and easy to install, and do not corrode even when buried in the soil. However, there is a problem that it is weak in impact strength, and when excavating the ground using an excavator for construction performed after burial, for example, water and sewage pipe construction, the claw of the excavator The polyethylene pipe may be damaged by hitting the buried polyethylene pipe. For this measure, for example, in the main pipe of a gas pipe having a high internal pressure, a protective sheet such as a polypropylene sheet is wound to improve the impact resistance of the polyethylene pipe. Specifically, in the case of a polypropylene sheet, a multilayer sheet in which five layers of thick polypropylene sheets are laminated is used. After the multilayer sheet 2 is wound around the polyethylene tube 1 as shown in FIG. Insulation locks 3 are wound and fastened and fixed, and in order to improve impact resistance, the multilayer sheet 2 is further wound thereon and fastened and fixed with an insulation lock.

For construction with the multilayer sheet 2 described above,
(1) Since the laminated sheet 2 has a structure in which thick polypropylene sheets are laminated in five layers, it is firm and is not easy to wind around a tube.
(2) Since the multilayer sheet 2 is strong as described above, it cannot be temporarily fixed using an adhesive tape or the like in a state of being wound around the tube, and is easily scattered in a state of being wound around the tube. It is not easy to wind and fix the insulation lock 3 around it, and it is particularly difficult to wind and fix the multilayer sheet 2 on it.
(3) In order to connect the branch pipes even after the multilayer sheet 2 is wound and fixed and buried, it may be necessary to dig up later and fuse and connect a saddle joint or service joint to the side of the pipe. When performing such pipe work, it is necessary to cut off the multilayer sheet at the location where the joint is to be attached and to expose the pipe surface of the location, but it is very difficult to cut the multilayer sheet 2, Risk of damaging the tube,
(4) Rolling is carried out by covering with earth and sand during embedding, but a gap is easily formed between the multilayer sheet 2 and the tube 1, particularly between the double-layered multilayer sheet 2, and after embedding this gap There is a risk that earth and sand will be carried along with the rainwater as a rainwater channel, causing local settlement at the buried site;
Etc.

  The present invention provides a method of embedding a plastic pipe into the soil that can solve the above problems, and a protective sheet that is wound around the plastic pipe in order to increase the impact resistance of the embedded plastic pipe. Objective.

The invention according to claim 1 is a method of embedding a plastic pipe used for a liquid transport pipe or a gas pipe suitable for use as a water and sewage pipe into the ground, and from a polypropylene obtained by stretching and defibration. A protective sheet having a structure in which a cushioning material is laminated on a flexible sheet woven or knitted as a defibrated yarn is wound around at least a part of the plastic tube with the sheet using the defibrated yarn outside, It is characterized by being buried in the ground,
The invention according to claim 2 is a protective sheet wound around a plastic pipe used as a liquid transport pipe or a gas pipe embedded in soil, and is a defibrated yarn made of polypropylene obtained by stretching and defibrating A cushioning material is laminated on a flexible sheet woven or knitted.

  Here, the flexible sheet using the defibrated yarn is preferably a woven or knitted defibrated yarn obtained by stretching and defibrating a polypropylene film obtained by extrusion molding. Thereby, strength can be increased while securing flexibility with a thin sheet. The defibrated yarn is preferably 2000 denier or more and has a tensile strength of 80 N / string or more.

  As the cushion material, for example, a nonwoven fabric such as a melt blown nonwoven fabric or a spunbond nonwoven fabric, sponge, rubber, soft resin or the like can be used. Among these, it is desirable to use a nonwoven fabric having a thickness of 8 mm or more. The cushion material is preferably as thick as possible as long as flexibility does not deteriorate, and this may be realized by laminating nonwoven fabrics.

  The protective sheet of each of the inventions has a basic structure in which a cushion material is laminated on a sheet using stretched defibrated yarn, but a plurality of these basic structures are laminated, that is, a plurality of sheets and cushion materials are alternately laminated. What forms a structure can also be used. Examples of the method for laminating the sheet and the cushion material include a method using thermocompression bonding, an adhesive, or a needle punch.

  The invention according to claim 3 is characterized in that, in the invention according to claim 2, an adhesive material, preferably an adhesive material with release paper attached, is applied to the back surface of the cushion material.

  According to the plastic pipe burying method of the invention according to claims 1 and 2 and the protective sheet used in the method, since the protective sheet has impact resistance and fracture resistance, when excavating using an excavator after embedding, Even if the claw of the excavator hits the plastic pipe, it can prevent the pipe from being damaged, or it can be hooked with the claw to prevent the protective sheet from being torn off, and the protective sheet is flexible due to its flexibility If it is necessary to cut the required part of the protective sheet, such as connecting a saddle joint or service tee joint to an existing pipe, it is possible to protect it by using a special tool (such as scissors). An effect that the sheet can be cut relatively easily is obtained, and a plurality of sheets and cushion materials are alternately laminated, that is, a sheet in which a plurality of protection sheets are laminated. Put it, it is possible to increase the pull shredded effect of preventing scratches and protective sheet of the tube by the claw of the excavator even more.

  The protective sheet wrapped around the plastic tube is fastened by fastening the insulation lock 3 around it as shown in FIG. 1 or by fastening vinyl tape (such as an anticorrosion tape) instead of the insulation lock. However, as in the invention according to claim 3, if a protective sheet having an adhesive material applied to the back surface of the cushion material is used, it can be easily and reliably fixed to the plastic tube by adhesion.

Hereinafter, a protective sheet according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 2 shows a cross section of the protective sheet 6 according to the present invention. This protective sheet is formed of, for example, a sheet 7 having a thickness of about 1 mm woven with a density of 13 pieces / inch using 2300 denier defibrated yarn made of polypropylene and a recycled resin such as polypropylene or polyethylene. The cushion material 8 made of a nonwoven fabric sheet having a thickness of about 10 mm is alternately laminated and laminated. The cushion material 8 on the back surface of the protective sheet is coated with an adhesive and a release paper 9 is pasted. ing. Here, as a method of fixing the sheet 7 and the cushion material 8 laminated on the sheet 7, a method using thermocompression bonding, an adhesive, or a needle punch is used.

In addition, as a method of producing a defibrated yarn made of polypropylene, for example, a polypropylene film obtained by extrusion molding is appropriately slit, for example, 25 mm wide to form a tape, and then stretched in a uniaxial direction and then applied to a defibrator, thereby For example, one having a width of 4 mm, a fineness (thickness) of 2300 denier, and a tensile strength of 100 N or more is obtained.
The protective sheet 6 is the same as or slightly longer than the circumference of the outer periphery of the plastic tube around which the width is wound.

  FIG. 3 shows a cross section in which the protective sheet 6 is peeled off from the release paper 9 and wound around a polyethylene pipe 11 as a plastic pipe.

  FIG. 4 shows an example in which a protective sheet 12 not coated with an adhesive is wound around a polyethylene pipe 11 and the insulation lock 3 is wound around and fixed around the polyethylene pipe 11.

  The protective sheet of the present invention is used to increase the impact resistance of a liquid transport pipe or gas pipe embedded in the soil, and a water and sewage pipe is suitable as the liquid transport pipe.

Sectional drawing which shows the prior art example of the protection sheet wound around a plastic pipe | tube. Sectional drawing of the protection sheet which concerns on this invention. Sectional drawing which wound and attached the protection sheet shown in FIG. 2 to a polyethylene pipe. Sectional drawing which fastened and secured the protection sheet wound around the polyethylene pipe with the insulation lock.

Explanation of symbols

1, 11 ··· Polyethylene pipe 3 · · Insulok 6 and 12 · · Protection sheet 7 · · Seat 8 · · Cushion material 9 · · Release paper

Claims (3)

  A method of embedding a plastic pipe used in a liquid transport pipe or gas pipe suitable for use as a water and sewage pipe in the ground, in which a defibrated yarn made of polypropylene obtained by stretching and defibrating is woven or A protective sheet having a structure in which a cushion material is laminated on a knitted flexible sheet is wound around at least a part of a plastic tube with the sheet using the defibrated yarn outside and embedded in the ground. How to embed plastic pipes.   A protective sheet wound around a plastic pipe used as a liquid transport pipe or gas pipe embedded in the soil, and is a woven or knitted defibrated yarn made of polypropylene obtained by stretching and defibrating A protective sheet for a plastic tube, characterized by having a structure in which a cushioning material is laminated on a sheet having properties.   The protective sheet according to claim 2, wherein an adhesive material is applied to the back surface of the cushion material.

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