JPS585590A - Structure of joining section of synthetic resin pipe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in the structure of joints of synthetic resin pipes.

Conventionally, various joining structures have been employed when joining polyethylene pipes coated for corrosion protection of water pipes, drainage pipes, or suspension cables. In other words, when joining pipes of the same diameter to each other, 1 - the two ends are brought together and the abutted parts are welded with filler metal, the butted ends are fused and joined, or the end of one pipe is widened. In some cases, the end of the tube is overlapped with the end of the other tube, and the end of the tube is fillet welded. In addition, as a joining structure for pipes of different diameters, the ends are overlapped and fillet welded, or heat-shrinkable steel is used to cover the overlapped part.
There is one that attaches a tube and connects this heat shrink tube to both tubes. However, all of these methods have drawbacks in terms of strength and workability. In other words, butt welding and fillet welding are not only labor-intensive, but also difficult to guarantee a perfect joint strength and seal.Also, with heat-shrinkable tubes, almost no joint strength can be expected; There is a risk that the tubes will shift from each other.

The present invention was made to solve these conventional drawbacks, and provides a structure with excellent workability and high joint strength.

Embodiments of the present invention will be described below with reference to the drawings. 1st
In the figure, 1 is a large-diameter pipe (pipe), 2 is a small-diameter pipe, and these are made of synthetic resin such as polyethylene. The ends of both pipes 1 and 2 are overlapped with each other, and a filler metal 3 is interposed between them. As shown in Fig. 2.6, this filler metal 3 is arranged in a waveform so that heating wires 31 such as nichrome wires are distributed over almost the entire surface between the belt-shaped polyethylene sheets. and is wound around the outer periphery of the small-diameter tube 2. Both ends of the heating wire 31 are connected to a power source B via a transformer 5. Further, a pressure jig 4 for tightening the large diameter pipe 1 is arranged on the outer periphery of the overlapping portion of the pipes 1 and 2.

As the pressing jig 4, as shown in FIG.
2 may hold a band iron (hoop) 41, and by tightening this hoop 41, the tube 1 can be compressed from the outer circumference. Alternatively, as shown in FIG. The metal fittings 7 and 8 may be tightened with bolts 9 on both sides thereof.

Next, a method for joining the tubes 1 and 2 will be explained. First, a filler metal 6 is wrapped around the outer periphery of a small diameter pipe 2, a large diameter pipe 1 is fitted on the outside so as to cover the filler metal filter, and a pressure jig 4 is placed on the outside of the filler metal 6. Set the state as shown in Figure 1. In this state, the tube 1 is tightened using the pressure jig 4 to press the filler metal 3 onto the inner circumferential surface of the tube 1 and the outer circumferential surface of the tube 2, and the heating wire 31 is energized. As a result, the polyethylene sheet 62 of the filler metal 6 is melted, and the tubes 1 and 2 are joined as shown in FIG.

When polyethylene sheet 32 is used as filler material 6, welding may be performed by heating at 200 to 220°C. After welding, the heating wire 31 is cut near the end of the tube 1, and the heating wire 61 in the joint is left as is, so-called buried.

Note that an appropriate core material may be inserted into the tube 2 in order to prevent the tube 1.degree. 2 from being deformed during tightening with the pressurizing jig 4. If the cable and filler material are inserted and filled into the pipes 1 and 2, as in the case of a hanging cable, no special deformation prevention means are required.

Further, in order to obtain a sufficient joint strength at the joint, the width B of the filler metal 6 should be at least the thickness t of the tubes 1 and 2, preferably 2 to 4 times the thickness t.

In the above embodiment, joining of pipes of different diameters was explained, but when joining pipes of the same diameter, it is possible to join them in the same manner as above by expanding the end of one pipe and fitting it over the other pipe. can. Further, instead of using a pressing jig, the filler material may be pressed by heat-shrinking the tube outside the overlapping portion. Further, instead of using a heating wire such as a nichrome wire as the filler material, an appropriate conductive substance may be placed in the filler material.

The bonded structure obtained by the above method has high bonding strength and excellent watertightness. Therefore, it is suitable for joining pipes for various purposes, but especially for hanging cables, bending load is applied to the joint by winding it around a drum, or as shown in Fig. 7, terminal equipment io, io
In order to apply a tensile force to the joint by lifting the pipe 1 between the pipes, the above-mentioned configuration having a high joint strength is preferable. In the conventional joint structure, when the suspension cable is wound around a drum, cracks often occur at the welded part.However, with the above structure, even when the cable is wound around a drum with a diameter approximately 15 times the outside diameter of the pipe. No cracks will occur. In addition, welding work conventionally required a very long time because the filler rod was melted sequentially along the welding area, but with the above method, the entire circumference of the pipe is heated at the same time, which is extremely time consuming. It only takes a short time.

Note that various synthetic resins other than polyethylene can be used as the material for the pipes to be joined, and it is preferable to use a filler material made of the same material as the pipes to be joined.

As explained above, in this invention, the ends of the pipes are overlapped and joined by interposing a heated wire-containing filler material between them, and the joint has high strength and sealing performance. It is also easy to work with.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the joining process showing an embodiment of the present invention;
Fig. 2 is a developed plan view of the filler metal, Fig. 3 is a cross-sectional view thereof, Figs. 4 and 5 are front views showing examples of pressing jigs, and Fig. 6 is a longitudinal cross-sectional view of the joint. , FIG. 7 is an explanatory diagram of the usage state of the suspension cable. 1... Large diameter pipe, 2... Small diameter pipe, 3... Melt filler metal, 31... Heating wire, 4... Pressure jig. Patent applicant Shin Iw Steel Wire Industry Co., Ltd. 7-

Claims (1)

[Claims] 1. A structure in which the ends of synthetic resin pipes of the same diameter or different diameters are overlapped and joined together, and a filler material containing a heating wire is provided between both pipes in the overlapped part. A joint structure of synthetic resin pipes in which both pipes are fused together with a 2. The structure of the synthetic resin pipe joint according to claim 1, wherein a cable is inserted into the pipe and a filler is filled between the cable and the pipe.