JPH0716932A - Connection of metal pipe and synthetic resin pipe - Google Patents

Abstract

PURPOSE:To simply and certainly connect a metal pipe and a synthetic resin pipe and to eliminate the leakage of a fluid from the connected pipe by internally or externally fitting the end part of the synthetic resin pipe to a sleeve and heating the electric heating wire interposed between the bonding surfaces of the sleeve and the synthetic resin pipe to weld and bond both of them. CONSTITUTION:When a synthetic resin pipe 2 is connected to a metal pipe 1, the end part of the synthetic resin pipe 2 is fitted and inserted in the expanded receiving port 11 of the metal pipe 1 and a current is supplied to an electric heating wire 4. A sleeve 3 having a female screw 31 provided to the inner peripheral surface thereof is fixed to the expanded receiving port 11 of the metal pipe 1 and the male screw 21 meshed with the female screw 31 is provided to the end part of the synthetic resin pipe 2. The male screw 21 provided to the end part of the synthetic resin pipe 2 is meshed with the female screw 31 of the metal pipe 1 after the electric heating wire 4 is wound around the end part of the synthetic resin pipe 2 along the root of the male screw 21. When a current is supplied to the electric heating wire 4 to generate heat, the male and female screws 21, 31 are melted to be strongly welded and bonded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for easily and surely connecting a metal pipe and a synthetic resin pipe.

[0002]

2. Description of the Related Art In the field of piping such as water supply pipes and gas pipes, metal pipes and synthetic resin pipes have been conventionally connected. The applicant of the present invention has previously disclosed in Japanese Patent Laid-Open No. 59-115810 that an end of a synthetic resin pipe is fitted into a socket provided at an end of a metal pipe, and the end of the synthetic resin pipe corresponding to the socket is inserted. A metal sleeve is set on the inner peripheral surface of the section, and the outer peripheral surface of the end of the synthetic resin pipe expanded on the outer peripheral side by expanding the diameter of the metal sleeve with a diameter expander has unevenness provided on the inner peripheral surface of the receiving port. I proposed a way to get into it and connect.

[0003]

However, in the case of this conventional connection method, when the diameter of the sleeve is expanded and the end of the synthetic resin pipe is expanded to the outer peripheral side, the outer peripheral surface of the pipe end expands. Since the unevenness provided on the inner peripheral surface of the diameter receiving port does not dig into it well, there is a risk that a gap may be created and the fluid in the pipe may leak or the synthetic resin pipe may separate at the connection portion.

The present invention has been made to solve the above-mentioned problems, and a metal tube and a synthetic resin tube can be easily and surely connected,
It is intended to provide a connection method in which there is no risk of leakage of fluid in a pipe.

[0005]

According to the present invention, when connecting a metal pipe and a synthetic resin pipe, a synthetic resin sleeve is fixed to an inner peripheral surface or an outer peripheral surface of an end portion of the metal tube. Next, the end of the synthetic resin pipe is inserted or externally inserted into the sleeve, and the heating wire interposed between both joint surfaces is heated to fusion-bond the synthetic resin pipe and the sleeve. And

[0006]

With the above structure, when the heating wire is energized to generate heat, the joint surface between the synthetic resin sleeve and the synthetic resin tube is melted and fusion bonded.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is a half sectional view showing an embodiment of the present invention, FIG. 2 is a half sectional view showing another embodiment of the present invention, and FIG. 3 is a half sectional view showing still another embodiment of the present invention. In the figure, 1 is a metal pipe such as a cast iron pipe or steel pipe, 2 is a synthetic resin pipe such as polyethylene or polybutene, and 3 is a sleeve made of the same kind of synthetic resin as the synthetic resin pipe 3.

First, the embodiment shown in FIG. 1 will be described. The metal tube 1 has an enlarged diameter receiving port 11 at one end, and the receiving port 1
An annular or spiral irregularity 12 is provided on the inner peripheral surface of 1. Further, annular grooves are provided on the opening side and the back side of the receiving port 11, and the rubber packing 13 is attached to each annular groove. A synthetic resin sleeve 3 is mounted on the inner peripheral surface of the expanded diameter receiving port 11, and the outer peripheral surface of the sleeve 3 is cut into the irregularities 12 and is pressed against the rubber packing 13 to be fixed.
Then, the heating wire 4 is embedded in a spiral shape on the inner peripheral surface of the sleeve 3, and both ends thereof are pulled out to the outside of the receptacle 11.

The synthetic resin sleeve 3 has an expanded diameter receiving port 1
It is possible to inject and mold a molten resin into the inner peripheral surface of No. 1 and integrally mold the heating wire 4 buried in the inner peripheral surface, but other than this, it is possible to use an appropriate means 11
The sleeve 3 can be fixed to the inner peripheral surface of the. For example, by inserting the sleeve 3 formed in a cylindrical shape into the receptacle 11,
The sleeve 3 may be heated and softened, and then the outer peripheral surface thereof may be fixed to the inner peripheral surface of the receiving port 11 while expanding the diameter with an appropriate diameter expanding tool. In the case of this molding method, it is preferable that the sleeve 3 is fixed to the inner peripheral surface of the receiving port 11 and then the heating wire 4 is embedded in the inner peripheral surface in a spiral shape.

Next, when the synthetic resin pipe 2 is connected to the metal pipe 1 described above, the synthetic resin pipe 2 is inserted into the expanded diameter receiving port 11 of the metal pipe 1.
The heating wire 4 is energized after the end portion of is inserted. Then, the heating wire 4 generates heat, and the inner peripheral surface of the sleeve 3 and the outer peripheral surface of the end portion of the synthetic resin pipe 2 are simultaneously melted and fusion-bonded.

In the metal tube 1 shown in FIG. 2, a sleeve 3 having an internal thread 31 is fixed to the inner peripheral surface of the expanded diameter receiving port 11, and an external thread 21 screwed to the internal thread 31 is attached to the end of the synthetic resin tube 2. Is provided. In the case of this embodiment, the heating wire 4 is wound along the valley of the male screw 21 provided at the end of the synthetic resin pipe 2 and then screwed into the female screw 31 of the metal pipe 1.
Therefore, when the heating wire 4 is energized to generate heat, the male screw 21
And the female screw 31 are melted and firmly fused and joined. If the metal sleeve 5 is inserted into the end portion of the synthetic resin tube 2 in advance during the connecting operation, it is possible to reliably prevent the diameter reduction when the end portion of the synthetic resin tube 2 is softened. The synthetic resin tube 2 and the sleeve 3 can be firmly fusion-bonded to each other.

In the embodiment shown in FIG. 3, the metal pipe 1 and the synthetic resin pipe 2 are connected via a joint 20 connected to the end of the synthetic resin pipe 2.
It is designed so that and can be connected. At the end of the metal tube 1, there is provided an inlet 14 having a reduced diameter with a step,
A synthetic resin sleeve 3 is attached and fixed to the outer peripheral surface of the spigot 14. The inner peripheral surface of the sleeve 3 bites into the unevenness 12 provided on the outer peripheral surface of the spigot 14, and is watertightly pressed against the rubber packings 13 mounted on the tip end side and the back side thereof.

On the other hand, the joint 20 is formed by spirally burying the heating wire 4 on the inner peripheral surface of a tube body made of the same kind of synthetic resin as the synthetic resin tube 2. In the case of this embodiment, the end 14 of the metal pipe 1 and the end of the synthetic resin pipe 2 are fitted into the respective ends of the joint 20. Therefore, when the heating wire 4 is energized to generate heat, one inner peripheral surface of the joint 20 is fusion-bonded to the outer peripheral surface of the end portion of the synthetic resin pipe 2, and the other inner peripheral surface of the joint 20 is of the sleeve 3. The metal pipe 1 and the synthetic resin pipe 2 are firmly joined by fusion bonding with the outer peripheral surface.

[0014]

As described above in detail, the present invention connects the metal pipe and the synthetic resin pipe through the synthetic resin sleeve fixed to the end portion of the metal pipe. The metal pipe and the synthetic resin pipe can be connected easily and reliably by simply energizing the heating wire interposed on the joint surface with the pipe, and there is no fear that the fluid in the pipe leaks from the joint portion.

[Brief description of drawings]

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

FIG. 2 is a half sectional view showing another embodiment of the present invention.

FIG. 3 is a half sectional view showing still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal tube 2 Synthetic resin tube 3 Synthetic resin sleeve 4 Heating wire 11 Expanded diameter receiving port 12 Unevenness 13 Rubber packing

Claims (1)

[Claims] 1. When connecting a metal pipe (1) and a synthetic resin pipe (2), a synthetic resin sleeve (3) is fixed to the inner peripheral surface or outer peripheral surface of the end of the metal pipe (1), The synthetic resin pipe (2) and the sleeve (3) are inserted into or externally inserted into the sleeve (3) and the heating wire (4) interposed between the joint surfaces is heated to generate heat. 3) A method for connecting a metal pipe and a synthetic resin pipe, which is characterized by fusion-bonding with.