JPH0424596B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention is a plastic pipe for transporting water or gas under high pressure, for example, 10 kg/ ^cm2 , and is reinforced with stainless steel or high-tensile metal tape. This relates to the connection part of the

<Prior Art> A conventional pipe connection portion of this type has a structure as shown in FIG. In Fig. 1, 1 is a plastic pipe with a circular cross section made of a material such as high-density polyethylene, and a reinforcing tape 2 made of a high-tensile strength material such as stainless steel is spirally wound around the outside of the pipe. In addition, this tape 2 is further covered with an anticorrosion layer 3 made of plastic such as polyethylene to prevent corrosion of the tape 2.

Reference numeral 4 denotes a sealing fitting made of steel or the like, which has a flange 6 formed at the outer end of a cylindrical portion 5. The outer side of the cylindrical portion 5 is tapered and has a plurality of protrusions 7 with a sawtooth cross section. It is formed in the circumferential direction.

After peeling off the tape 2 and the plastic anti-corrosion layer 3 on the outside of the end of the pipe 1 to leave only the pipe 1, the cylindrical part 5 of the seal fitting 4 is pushed into the end of the pipe 1, and the end of the pipe 1 is removed. The portion is expanded along the outer taper of the cylindrical portion 5 to form a tapered shape. A holding fitting 8 is made of the same material as the sealing fitting 4, and consists of a flange 9 and an annular holding part 10, and the inner periphery of the holding part 10 is tapered.

This holding fitting 8 has the inside of its holding part 10 in close contact with the outer periphery of the tapered end of the pipe 1, and has a plurality of insertion holes provided in the flange 6 of the sealing fitting 4 and a flange 9 of the holding fitting 8. It is tightened by bolts 11 and nuts 12 inserted through the plurality of insertion holes, and a spring washer or the like is attached to the nut 12 to prevent it from loosening.

Reference numeral 13 denotes a metal wire such as a copper wire that is spirally wound around the outside of the tape 2 on the outside of the pipe 1 on the outside of the flange 9, and is wound around the area where the anti-corrosion layer 3 is removed from the outer periphery of the end of the anti-corrosion layer 3. The reinforcing layer 14 covers the entire filament 13 by applying polyethylene or the like to the outside of the filament 13.

<Problems to be Solved by the Invention> The conventional high-pressure plastic pipe connection part has the above structure, but the part sandwiched between the holding part 10 of the holding fitting 8 and the cylindrical part 5 of the sealing fitting 4 is the pipe 1.
It has become only.

Therefore, due to the creep effect of polyethylene, which is the material of the plastic pipe 1, the presser metal fitting 8
Only the polyethylene portion stretches out at the inner peripheral portion of the flange 9, creating a gap between the presser metal fitting 8 and the reinforcing tape 2, and the withstand pressure of this portion is significantly reduced.
In the end, there is a problem that the pipe 1 breaks.

The pipe connection part of the present invention was made to solve the problems of the conventional pipe connection parts as described above, and the outer periphery of the plastic pipe at the part that is tightened by the holding part of the holding fitting is also reinforced with tape. The purpose of this invention is to provide a connection that can withstand high pressures.

<Means for Solving the Problems> The present invention involves pushing a cylindrical part of a sealing fitting inside the end of a plastic pipe wrapped with reinforcing tape on the outside, and using a taper on the outside of this cylindrical part, the end of the plastic pipe is By enlarging the area, fitting the annular holding part of the holding fitting outside of this enlarged part, and tightening the flanges of the sealing fitting and holding fitting with bolts and nuts, the multiple protrusions on the outside of the cylindrical part of the fitting are attached to the plastic pipe. A reinforcing tape that is wound around the outside of the enlarged part of the plastic pipe to reinforce the enlarged part, and a heat shrink tube that covers the reinforcing tape in the enlarged part, in the connecting part which is cut into the inner part of the enlarged part of the plastic pipe. and an annular presser portion is attached to the outside of the heat-shrinkable tube in the enlarged portion.

<Function> According to the present invention, since the reinforcing tape and the heat shrink tube are wrapped around the outside of the expanded portion at the end of the plastic pipe, the expanded portion can be reinforced more strongly. Therefore, it is possible to reliably prevent a problem in which the plastic pipe, which is tightened between the cylindrical part of the seal fitting and the holding part of the holding fitting, stretches out due to the creep of the plastic and a gap is formed.

<Example> Hereinafter, an example of the connecting portion of a plastic pipe of the present invention will be described based on FIG. 2.

In FIG. 2, the connecting part of the plastic pipe basically consists of a reinforcing tape 2 wrapped around the outside of the end of the pipe 1 to reinforce the end, and a heat shrink tube covering the reinforcing tape 2. 15, and an annular presser portion 10 is attached to the outside of this heat-shrinkable tube 15. The rest of the structure is the same as the conventional plastic pipe connection shown in FIG.

Next, we will explain how to connect the plastic pipes.

First, the anti-corrosion layer 3 on the outside of the end of the pipe 1 is removed, and the reinforcing tape 2 on the end of the pipe 1, which is enlarged by the cylindrical part 5 of the seal fitting 4, is once peeled off and the end of the plastic pipe 1 is removed. make it easy to spread. After the cylindrical part 5 of the seal fitting 4 is pushed inside the end of the pipe 1 and attached, the reinforcing tape 2 is rewound to the tapered end of the pipe 1. A heat-shrinkable plastic tube 15 is placed on the outside of the exposed portion and heat-shrinked to make the outer surface of the tube 15 smooth and prevent corrosion, and the annular holding part 10 of the holding fitting 8 is brought into close contact with the surface of this tube 15. Configure it as follows.

The structure of the connection part of this invention is the above-mentioned structure, but in the case of connection with this connection part or with the flange 18 at the end of another pipe 16 as shown in FIG. The distance between the flange 6 of the seal fitting 4 and the loose flange 17 is kept constant, and the flange 6,
It is preferable to connect both flanges 6 and 17 with bolts 11 and nuts 12 inserted through a plurality of holes provided in 17.

In the above configuration, the end of the pipe 1 reinforced with the tape 2 made of stainless steel or other high tensile strength material is connected to the tape 2 and the heat shrink tube 1.
It is reinforced with 5. Therefore, there is no possibility that the plastic pipe 1, which is clamped between the cylindrical part 5 of the seal fitting 4 and the holding part 10 of the holding fitting 8, will stretch out due to the creep of the plastic and create a gap. , a plastic pipe connection with good pressure resistance can be obtained.

<Effects of the Invention> As explained above, according to the present invention, since the reinforcing tape and the heat shrink tube are wrapped around the outside of the expanded portion at the end of the plastic pipe, the expanded portion is more strongly reinforced. . Therefore, it is possible to reliably prevent the problem that the plastic pipe, which is tightened between the cylindrical part of the sealing fitting and the holding part of the holding fitting, stretches out due to the creep of the plastic and a gap is formed. This has the effect of providing connections for plastic pipes.

[Brief explanation of drawings]

FIG. 1 is a partially longitudinal side view showing an example of a conventional plastic pipe connection part, and FIG. 2 is a partially longitudinal side view showing an embodiment of the plastic pipe connection part of the present invention. 1...Plastic pipe, 2...Reinforcement tape, 3
...Anti-corrosion layer, 4...Seal fitting, 5...Cylindrical part, 6, 9
...Flange, 7... Projection, 8... Holding metal fitting, 10... Annular holding part, 11... Bolt, 12... Nut, 15...
Heat shrink tube.

Claims (1)

[Claims] 1 Push the cylindrical part of the seal fitting inside the end of the plastic pipe wrapped with reinforcing tape on the outside, expand the end of the plastic pipe with the taper on the outside of this cylindrical part, and press it to the outside of this expanded part. A plastic pipe in which the annular holding part of the fitting is fitted and the flanges of the sealing fitting and holding fitting are tightened with bolts and nuts so that the multiple protrusions on the outside of the cylindrical part of the fitting bite into the inside of the enlarged part of the plastic pipe. At the connection part of the pipe, a reinforcing tape is wound around the outside of the enlarged part of the plastic pipe to reinforce the enlarged part, and a heat shrink tube is provided to cover the reinforcing tape in the enlarged part. A plastic pipe connection section characterized by having an annular presser attached to the outside of a heat-shrinkable tube.