JPH10220676A - Electrically fused joint for synthetic resin pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To insert a pipe end section into a joint body with ease, determine the length of the insertion part of the pipe end section into the joint body with ease and provide high joint strength. SOLUTION: In an electrically fused joint for synthetic resin pipes, which is provided with a cylindrical joint body 10, which is made of the same material as that of the synthetic resin pipe and is to be mounted in the pipe end section 1 of a synthetic resin pipes butted to each other, and a current carrying heating body 11, which is buried in the joint body 10, the inner diameter of the joint body 10 becomes large continuously toward outside from the center section in the axial direction.

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 for a synthetic resin pipe, and more particularly, to easily insert a pipe end into a joint body, and to easily insert the tube end into the joint body. The present invention relates to an electric fusion joint for a synthetic resin pipe, which can be determined and can obtain a high joining strength.

[0002]

2. Description of the Related Art Conventionally, there is an electric fusion joint for a synthetic resin pipe as a joint for a polyethylene resin pipe used for a water pipe or the like. As shown in FIG. 3, the electric fusion joint for a synthetic resin pipe includes a tubular joint body 2 made of polyethylene resin which is mounted across both pipe ends 1, and a coil embedded in the joint body 2. And a heating element 3 made of a nichrome wire. A power supply 5 is connected to the energizing heating element 3 through a terminal 4.
Current flows from the The current is controlled by the controller 6.

In order to join the pipe ends 1 by the above-mentioned conventional joint, the following is performed. That is, the surface of the pipe end 1 is cut to remove a portion degraded by oxidation or the like. Next, the joint main body 2 is mounted over both pipe ends 1. Then, electricity is supplied to the electric heating element 3 to heat and melt the outer surface of the pipe end 1 and the inner surface of the joint body 2. Thus, the two tube ends 1 are fused and joined to each other.

[0004] As shown in FIG. 4, the joint body 2 is provided with an indicator 7 for managing the molten state of the outer surface of the pipe end 1 and the inner surface of the joint body 2. The indicator 7 is formed of a rod inserted into a through hole 8 formed in the joint body 2. When the outer surface of the tube end 1 and the inner surface of the joint body 2 are melted by energization, the tube end 1
Since the interface pressure at the contact portion between the joint and the joint body 2 increases,
The indicator 7 rises. By monitoring the amount of protrusion, the molten state of the outer surface of the pipe end 1 and the inner surface of the joint body 2 can be managed. When the indicator 7 protrudes from the surface of the joint body 2 as shown in FIG.
It is determined that the outer surface of the pipe end 1 and the inner surface of the joint body 2 have completely melted, and the energization is stopped.

[0005]

However, the above-mentioned conventional joint has the following problems. Since the inner diameter of the joint body 2 is substantially equal to the outer diameter of the tube end 1, it is difficult to insert the tube end 1 into the joint body 2. In particular, it becomes difficult to insert a large-diameter tube because the weight increases. If the fusion area between the outer surface of the pipe end 1 and the inner surface of the joint body 2 is not large, the joining strength is low. Therefore, it is necessary to lengthen the joint body 2 to some extent. Since the inner surface of the joint body 2 is a parallel cylindrical surface, it is necessary to devise a way to position the butted portion of the pipe end 1 at the center of the joint body 2.

Accordingly, an object of the present invention is to easily insert a pipe end into a joint body, easily determine the length of insertion of the tube end into the joint body, and obtain high joint strength. It is an object of the present invention to provide an electric fusion splicing method for a synthetic resin pipe, which can be used.

[0007]

According to the first aspect of the present invention,
An electric power for a synthetic resin pipe, comprising: a tubular joint body of the same material as that of the synthetic resin pipe, which is attached to a pipe end of the synthetic resin pipe butted with each other; and an electric heating element embedded inside the joint body. The fusion joint is characterized in that the inner diameter of the joint body is continuously increased outwardly with respect to the center in the axial direction.

According to a second aspect of the present invention, a tubular joint body made of the same material as the synthetic resin pipe, which is attached to the pipe ends of the synthetic resin pipes butted with each other, is embedded in the joint body. An electric fusion joint for a synthetic resin pipe provided with an electric heating element, characterized in that the inner diameter of the joint main body is gradually increased outward from a center portion in the axial direction as a boundary. It is.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the electric fusion joint for a synthetic resin pipe of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an electric fusion joint for a synthetic resin pipe of the present invention mounted on a pipe end, and FIG. 2 is a cross-sectional view of another synthetic resin pipe of the present invention mounted on the pipe end. It is sectional drawing which shows an electrofusion joint.

As shown in FIG. 1, the electric fusion joint for a synthetic resin pipe of the present invention has a cylindrical joint body 10 having an inner diameter continuously increasing outward from a center portion in the axial direction. And a current-carrying heating element 11 made of a coiled nichrome wire embedded in the joint body 10. The joint body 10 is made of the same material as the polyethylene resin pipe end 1 to be joined. Although not shown, an indicator for monitoring the above-mentioned melting state is also provided.

By continuously increasing the inner diameter of the joint body 10 and making the inner surface of the joint body 10 a conical surface, the area of the inner surface of the joint body 10 is wider than that of the conventional joint having a parallel cylindrical surface. Become. Accordingly, the area of fusion between the outer surface of the pipe end 1 and the inner surface of the joint body 10 is accordingly increased,
Increases bonding strength.

As the electric heating element 11, an electric heating fiber made of micro metal fiber and aramid fiber can be used in addition to the nichrome wire. The current-carrying heating fiber has substantially the same electric heat characteristics as the nichrome wire, has the advantage that there is no risk of disconnection, and that it can be easily embedded in the joint body 10.

According to the electric fusion joint for a synthetic resin pipe of the present invention configured as described above, the pipe ends 1 are joined as follows. That is, the pipe end 1 is connected to the joint body 10.
Is cut into a conical surface so as to match the inner surface shape. This is also to remove a portion degraded by oxidation or the like. Next, the pipe end 1 is inserted into the joint body 10. In this case, the tip of the pipe end 1 is formed to be tapered, and
Since the inner surface of the joint main body 10 is formed in a conical shape so as to conform to this, the pipe end 1 can be easily inserted into the joint main body 10, and the stopper 9 is provided on the inner surface of the joint main body 10.
Is formed, the insertion length of the pipe end 1 into the joint body 10 is naturally determined. That is, simply the pipe end 1 is connected to the joint body 1.
The butt portion is naturally located at the center of the joint body 10 simply by inserting it into the joint body 10. These effects are more effective especially for a large-diameter tube. Then, an energizing cable 13 (see FIG. 4) is connected to the terminal 12, and the energizing heating element 11 is energized to heat and melt the outer surface of the pipe end 1 and the inner surface of the joint body 10. In this way, the pipe ends 1 are joined.

The joint body 10 may have a shape as shown in FIG. The joint body 10 has an inner diameter gradually increasing outward toward the center in the axial direction, and other configurations are the same as those of the joint of FIG. In this case, it is needless to say that the outer surface of the pipe end 1 also needs to be cut in a stepwise manner so as to match the inner surface of the joint body 10.

With the joint body 10 described above, the area of the inner surface of the joint body 10 is larger than that of the conventional joint having a parallel cylindrical surface. Accordingly, the area of fusion between the outer surface of the pipe end 1 and the inner surface of the joint body 10 is accordingly increased, and the joining strength is increased. Moreover, the tip of the tube end 1 is formed to be tapered,
And since the inlet of the joint main body 10 is formed widely,
It is easy to insert the pipe end 1 into the joint main body 10, and even if the stopper 9 is not formed on the inner surface of the joint main body 10, the insertion length of the pipe end 1 into the joint main body 10 is naturally determined.

[0017]

As described above, according to the present invention, the inner diameter of the joint body is continuously increased outward from the center in the axial direction, or is increased stepwise. By doing so, the fusion area between the outer surface of the pipe end and the inner surface of the joint body is increased, the joining strength is increased, and the tip end of the tube end is formed to be tapered, and the inlet of the joint body is closed. Because it is formed widely, it is easy to insert the pipe end into the joint body, and even if a stopper or the like is not formed on the inner surface of the joint body, the insertion length of the pipe end into the joint body is naturally determined. A useful effect is provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an electric fusion joint for a synthetic resin pipe of the present invention mounted on a pipe end.

FIG. 2 is a cross-sectional view showing another electric fusion joint for a synthetic resin pipe of the present invention attached to a pipe end.

FIG. 3 is a cross-sectional view showing a conventional electric fusion joint for a synthetic resin pipe attached to a pipe end.

FIG. 4 is a cross-sectional view showing a fusion state between an outer surface of a pipe end and an inner surface of a joint body.

FIG. 5 is a cross-sectional view showing a protrusion of the indicator.

[Explanation of symbols]

 1: Pipe end 2: Joint body 3: Electric heating element 4: Terminal 5: Power supply 6: Controller 7: Indicator 8: Through hole 9: Stopper 10: Joint body 11: Electric heating element 12: Terminal 13: Electric cable

Claims (3)

[Claims] 1. A tubular joint body of the same material as that of the synthetic resin pipe, which is attached to a pipe end of the synthetic resin pipe butted against each other, and a current-carrying heating element embedded inside the joint body. In the electric fusion joint for synthetic resin pipes, the inner diameter of the joint main body is continuously increased outward toward a center part of the joint body in the axial direction. . 2. A tubular joint body of the same material as that of the synthetic resin pipe, which is attached to a pipe end of the synthetic resin pipe butted against each other, and a current-carrying heating element buried inside the joint body. In the electric fusion joint for synthetic resin pipes, the inner diameter of the joint main body is gradually increased outward from a center portion in the axial direction as a boundary, wherein the electric fusion joint for synthetic resin pipes is characterized in that: . 3. The electric fusion joint for a synthetic resin pipe according to claim 1, wherein the energizing heating element is made of a nichrome wire or an energizing heating fiber.