JPH08312868A - Electric fusion joint - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an electric fusion joint capable of reliably and firmly fusion-bonding different types of polyethylene pipes. [Structure] A cylindrical joint main body 1 is formed of polyethylene resin, receiving ports 11 are provided at both ends of the joint main body 1, and a heating wire 2 is embedded in a spiral shape on the inner peripheral surface of each receiving port. And one receptacle 11 in which the heating wire 2 is embedded
High-density or medium-density polyethylene resin layer 1a on the inner peripheral surface of
And the low-density polyethylene resin layer 1b is formed on the inner peripheral surface of the other receiving port 11. [Effect] The polyethylene pipe of high density or medium density on the one hand and the polyethylene resin pipe of low density on the other hand can be surely and firmly fused and connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric fusion joint in which a heating wire is embedded in the inner peripheral surface of a socket of a joint body. More specifically, one side is a high density or medium density polyethylene pipe and the other side is a low density polyethylene pipe. The present invention relates to an electric fusion joint that can be suitably used when connecting to a pipe.

[0002]

2. Description of the Related Art Conventionally, for connection of gas pipes, water supply pipes, hot water supply pipes, etc., electrical outlets have been provided with receptacles at both ends of a synthetic resin joint body, and heating wires were spirally embedded in the inner peripheral surface of each receptacle. A fusion splice is used.

[0003]

By the way, polyethylene pipes are used for gas pipes and water / hot water pipes.
Since this polyethylene pipe has a pipe made of high-density, medium-density, and low-density polyethylene resin, the conventional electric fusion joint could not be used to connect polyethylene pipes of different types. For example, to connect high-density polyethylene pipes, an electric fusion joint whose joint body is made of high-density polyethylene resin is used. It could not be used to connect pipes. The present invention has solved the above problems and provides an electric fusion joint capable of reliably and firmly fusion-bonding polyethylene pipes of different types.

[0004]

The electric fusion-bonded joint of the present invention is formed by forming a cylindrical joint main body from polyethylene resin, and providing receiving openings at both ends of the joint main body, and at the inner peripheral surfaces of the respective receiving openings. A heating wire is embedded in a spiral shape, and a high-density or medium-density polyethylene resin layer is formed on one inner peripheral surface of the receiving port in which the heating wire is embedded, and a low density is formed on the other inner peripheral surface of the receiving port. The polyethylene resin layer is formed.

[0005]

When the pipe is installed, a high-density or medium-density polyethylene pipe is inserted into one of the receiving ports of the joint body, and a low-density polyethylene pipe is inserted into the other receiving port. Therefore, when the heating wires embedded in the inner peripheral surfaces of the respective receiving ports are energized to generate heat, the high density or medium density polyethylene resin layer formed on the inner peripheral surface of one of the receiving ports and the outer peripheral surface of the high density or medium density polyethylene pipe Melts and is fusion-bonded, and the low-density polyethylene resin layer formed on the other inner peripheral surface of the receiving port and the outer peripheral surface of the low-density polyethylene pipe are melted and fusion-bonded. Further, when the joint body is made of high-density or medium-density polyethylene resin, mechanical strength such as wear resistance and impact resistance is improved.

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is a half sectional view of an electric fusion joint showing an embodiment of the present invention, and FIG. 2 is a sectional view of an electric fusion joint showing another embodiment of the present invention and a manufacturing process thereof. Is a joint body made of polyethylene resin, 1a is a high-density or medium-density polyethylene resin layer, 1b is a low-density polyethylene resin layer,
2 is a heating wire.

First, the electric fusion splicing joint shown in FIG. 1 will be described. In this electric fusion joint, a cylindrical joint body 1 is formed of polyethylene resin, receiving ports 11 are provided at both ends of the joint body 1, and a bare heating wire 2 is provided on the inner peripheral surface of each receiving port 11. In which a polyethylene resin layer 1a having a high density or a medium density is formed on the inner peripheral surface of one receiving port 11, and a low density is formed on the inner peripheral surface of the other receiving port 11. A polyethylene resin layer 1b is formed.

As the heating wire 2, a nichrome wire or the like having a wire diameter of 0.2 mm to 3.0 mm can be used according to the diameter size of the joint body 1, and the interval between the heating wires 2 spirally wound is 0. .5
It can be appropriately set in the range of mm to 3.0 mm.
In addition, a pair of terminal pins 3 project from the outer circumference of both ends of the joint body 1, and both ends of the heating wire 2 are connected to the respective terminal pins 3.

This electric fusion joint is integrally formed by injection molding. As an example of this, a cylindrical body forming the high-density or medium-density polyethylene resin layer 1a and a cylindrical body forming the low-density polyethylene resin layer 1b are prepared, and a spiral engraved on the outer peripheral surface of each cylindrical body is prepared. It can be manufactured by fitting the bare heating wire 2 in the groove, setting it in the mold, and then injecting the molten resin. In the case of this embodiment, the polyethylene resin constituting the joint body 1 may be any of high density, medium density or low density polyethylene resin. Further, the joint body 1 is not limited to the illustrated socket, but may be an elbow, and H, M, L, etc. are displayed on the outer periphery of the end of the joint body 1 in accordance with the density of the polyethylene resin layers 1a, 1b. It is good to put it.

Next, another embodiment of the electric fusion splicing joint of the present invention and its manufacturing method will be described with reference to FIG. In this electric fusion-bonding joint, the inner peripheral surface of one receiving port 11 is embedded with the outer surface of the heating wire 2 coated with a high-density or medium-density polyethylene resin layer 1a. The outer peripheral surface of the heating wire 2 is embedded in the inner peripheral surface thereof with the low density polyethylene resin layer 1b.

In manufacturing this electric fusion joint, first, the heating wire 2 whose outer surface is covered with the resin layers 1a and 1b is wound around the outer peripheral surface of the core 4. In addition, A in the drawing is a joint for connecting both heating wires 2. Next, the core 4 around which the heating wire 2 is wound is set in a mold 5 having a half-divided shape, and the terminal pins 3 connected to the ends of the heating wires 2 are held by the terminal holding member 6 while the metal is held. The mold 5 is closed.

Therefore, when the molten resin is injected into the cavity formed between the core 4 and the mold 5 and cured, a receiving port 11 in which the heating wire 2 is embedded is formed at both ends of the joint body 1. While the high density or medium density polyethylene resin layer 1a is formed on the inner peripheral surface of the receiving port 11 of the other receiving port 1
An electric fusion-bonded joint in which a low-density polyethylene resin layer 1b is formed on the inner peripheral surface of 1 is obtained. Also in the case of this embodiment, the polyethylene resin forming the joint body 1 may be any of high density, medium density or low density polyethylene resin.

When connecting polyethylene pipes using this electric fusion joint, a high-density or medium-density polyethylene pipe is inserted into one receptacle 11 of the joint body 1 and a low-density polyethylene pipe is inserted in the other receptacle 11. Insert a polyethylene tube. Therefore, when the heating wire 2 embedded in the inner peripheral surface of each of the receiving ports 11 is energized to generate heat, the high density or medium density polyethylene resin layer 1a formed on the inner peripheral surface of one of the receiving ports 11 and this receiving port 11a. Mouth 1
The outer peripheral surface of the high-density or medium-density polyethylene pipe inserted in 1 is melted and fusion-bonded, and the low-density polyethylene resin layer 1b formed on the inner peripheral surface of the other receiving port 11 and this receiving port 1
The outer peripheral surface of the low-density polyethylene pipe inserted in No. 1 is melted and firmly fusion-bonded.

[0014]

As described above in detail, in the electric fusion splicing joint of the present invention, a high density or medium density polyethylene resin layer is formed on the inner peripheral surface of one receiving port, and a low density is formed on the inner peripheral surface of the other receiving port. Since the polyethylene resin layer of No. 1 is formed, it is possible to reliably and firmly fusion-bond the different types of polyethylene pipes. In addition, if the joint body is made of high-density or medium-density polyethylene resin, the mechanical strength will be improved, so vibrations that act on the joint during or after pipe construction at the site
The electric fusion-bonded joint will not be damaged due to impact and the fluid in the pipe will not leak.

[Brief description of drawings]

FIG. 1 is a half sectional view of an electric fusion joint showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an electric fusion splicing joint and a manufacturing process thereof according to another embodiment of the present invention.

[Explanation of symbols]

 1 Joint body 1a High-density or medium-density polyethylene resin layer 1b Low-density polyethylene resin layer 2 Heating wire 3 Terminal pin

Claims (2)

[Claims] 1. An electrofusion joint in which a cylindrical joint body is formed of polyethylene resin, receiving ports are provided at both ends of the joint body, and heating wires are spirally embedded in the inner peripheral surface of each receiving port. It is characterized in that a high-density or medium-density polyethylene resin layer is formed on the inner peripheral surface of one receiving port in which the heating wire is embedded, and a low-density polyethylene resin layer is formed on the inner peripheral surface of the other receiving port. And an electric fusion joint. 2. The electric fusion joint according to claim 1, wherein the joint body is formed of a high-density or medium-density polyethylene resin.