JPS58219018A - Jointing method of synthetic resin tube - Google Patents

Abstract

PURPOSE:To obtain high jointing strength with good workability, by a method wherein end parts of synthetic resin tubes are fitted with each other, annular filler material with a heating wire being caused to be between the both tubes of said fitting part, said both tubes being heated to a softening temperature by applying power to the heating wire and pressed from outer periphery, and they are heated to a fusing temperature thereafter. CONSTITUTION:The end parts of synthetic resin tubes 1 and 2 to be jointed are fitted with each other, and the clearance between both tubes 1 and 2 is caused to be uniform by allowing a spacer 4 to be between them. Then, the filler material 5 with the heating wire 51 are annularly fit between both tubes 1 and 2. Thereafter, the tubes 1 and 2 and the filler material 5 are heated to a softening temperature and softened by applying power to the heating wire 51 in this condition. They are pressed from outer periphery with a pressure jig 9, and both tubes 1 and 2 are caused closely to stick to each other through filler material. Then, the heating wire is charged with high current and they are heated to a fusing temperature. Thus, the synthetic resin tubes can be jointed with each other in high strength with good workability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for joining synthetic resin pipes.

Conventionally, various joining methods have been employed when joining polyethylene pipes coated for corrosion protection of water pipes, drainage pipes, and suspension cables.

In other words, when joining pipes of the same diameter to each other, the two ends are brought together and the abutted parts are welded with filler metal, the butt ends are fused and joined, or the ends of one pipe are widened and the other end is welded. This method involves fillet welding the end of the pipe after overlapping it with the end of the pipe. In addition, as a method for joining pipes of different diameters, the ends may be overlapped and fillet welded, or several pieces of heat-shrinkable tubing may be placed to cover the overlapping portion, and this heat-shrinkable tubing may be joined to both pipes. There is something that makes you do it. However, all of these methods have drawbacks in terms of strength and workability. That is,
Butt welding and fillet welding not only take a long time to perform, but also make it difficult to guarantee a perfect joint strength and seal.Also, with heat-shrinkable tubes, almost no joint strength can be expected; may shift to Ij and IA.

The present invention has been made to solve these conventional drawbacks, and provides a joining method that has excellent workability and high joining strength. That is, the present invention involves combining the ends of synthetic resin pipes to be joined together, interposing a heating wire (tJ) and a welding filler (tl) in an annular manner between the two pipes at the fitting portion, and energizing the heating wire. By doing this, both tubes at the fitting part are heated to the softening temperature and pressurized from the outer periphery, and then heated to the melting temperature to melt and fuse the tubes together (A). .

Embodiments of the present invention will be described below with reference to the drawings. 1st
Figures (A) and 2) show the joining process. First, as shown in (A), the pipes 1.2 to be joined are connected to r4. Both pipes 1 are fitted together and a spacer 4 is interposed between the gates.
, Make the gap between the two gates uniform. The tubes 1.2 are IU-filled with a synthetic resin such as polyethylene, and have different diameters, but in the case of tubes of the same diameter, the end of one tube may be widened in advance.

The spacer 4 may be made of the same material as the tubes 1 and 2, divided into an appropriate number in the same direction and pushed between the tubes 1 and 2. Next, as shown in FIG. 1(b), a filler material 5 with a heating wire 51 inserted therein is inserted between the tubes 1 and 2 in an annular manner. This fitting can be easily performed since a predetermined gap is uniformly formed by the spacer 4.

As shown in FIG. 2, the filler metal 5 is constructed by winding a sheet 50 of the same phase as the tube 1.2 in a spiral shape with a heating wire 51. For example, the heating wire has a wire diameter of 0.1 to 2. Q
Using a nickel-chromium wire of about 1 to 1 mm in diameter,
It is sufficient to wrap it at a pitch of about 0 mm. Also sheet 5
0 preferably has a thickness of 115 to 1/2 of the thickness of tubes 1 and 2, and a width of 1 to 10 times the thickness of tube 1.2.

Next, as shown in FIG.
is connected to a power source 8 via an ammeter 6 and a transformer 7. Next, as shown in FIG.
0 is placed, and the pressure jig 9 is used to tighten it from the outside. As this pressing jig, those shown in FIGS. 3(a) and 3(b) can be adopted. That is, the known ring type tightening may be one in which a tool 91 or a two-part annular body 95 are connected by a hinge 94 and tightened by a bolt 96. These apply force evenly to the outer periphery of the tube 1 via the buffer material 40. 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 9. 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.

In the state shown in Figure 1 above, the heating wire 51 is energized and the tube 1.2 is heated.
Then, the filler metal 5 is heated to a softening temperature, for example, about 110° C. in the case of polyethylene pipes, and then pressurized from the outer periphery with a pressure jig 9 to form both pipes 1.

2 are brought into close contact with each other via a filler metal. Then heating wire 5
1 is heated to about 200 to 220°C by applying a higher current to fuse it. After cooling to below the softening temperature after fusion, the pressure jig 9 and the buffer material 40 are removed, and the heating wire 51 is connected to the pipe 1.
The heating wire 51 inside the joint is left as is, so-called buried. As a result, both tubes 1 and 2 are joined as shown in FIG.

By applying pressure while heating to the softening temperature and then heating to the melting temperature in this manner, the pressure can be evenly distributed over the joint, and the appearance of the joint can be improved. Furthermore, when the temperature is increased from a softened state, variations in temperature distribution can be made smaller than when the temperature is raised all at once to the melting temperature. In addition, since heating wires are arranged on the outer surface of the filler metal 5, the filler metal 5, the inner circumferential surface of the tube 1, and the outer circumferential surface of the tube 2 are efficiently heated, and fusion welded with minimal heat. can be made to do so.

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, it is used to apply bending load to the joint by winding it around a drum, or to apply tensile force to the joint. The above structure with high strength is preferable.

As explained above, the present invention involves fitting the ends of a tube together, interposing a heating wire f'' filler metal between them, softening the
It is designed to be fusion welded after pressurization, and it is uniformly joined in the circumferential direction to form a joined structure with an excellent appearance, has excellent joint strength, and can be joined in a short time. It is.

[Brief explanation of the drawing]

Figures 1 (a) to 3) are cross-sectional explanatory views of the joining process showing an embodiment of the present invention, Figure 2 is a plan view of the filler metal, and Figure 3 (a)
(B) is a cross-sectional view and a side view of the pressurizing jig, respectively, and FIG. 4 is a longitudinal cross-sectional view of the pipe after joining. 1.2... Pipe, 3... Fitting portion, 4... Spacer, 5... Filler metal, 9... Pressure jig, 40...
Cushioning material, 51... heating wire. Figure 1 (D)

Claims (1)

[Claims] 1. The ends of the synthetic resin pipes to be joined are fitted into each other, and a heating wire fq is inserted in an annular shape between the two pipes at the fitted part.
By applying electricity to the heating wires, both tubes at the fitting part are heated to a softening temperature and pressurized from the outer periphery. A method for joining synthetic resin pipes, characterized by fusion bonding. 2. A method for joining synthetic resin pipes as set forth in claim 1, characterized in that a spacer is interposed in the fitting portion of both pipes to make the gap between both pipes uniform, and then a filler material is inserted. . 3. In claim 1 or 2, the heating wire f is provided by winding a sheet of the same citrus material as the tube in a spiral shape with a heating wire.
A method for joining synthetic resin pipes, characterized by using an XJ filler metal. 4. Claims 1, 2, or 3 of the synthetic resin pipe, characterized in that the above-mentioned pressurization is performed by tightening the outer periphery of the fitting portion of the pipe with a band via a cushioning material. Joining method.