JP2000088170A - Adapter for connecting steel pipe to be connected by using electric fusion coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and easily connect a steel pipe by using an electric fusion coupling by providing a metallic fixing ring coated with thermoplastic resin on an outside face and a fixing means sealed and fixed to the outside face of a connecting steel pipe, in an adapter for connecting steel pipe useful for connecting an electric fusion coupling for connection and the steel pipe. SOLUTION: In the case that a steel pipe 31 and an electric fusion coupling 32 are connected by using an adapter 30, a fixing ring 10 is made of steel and a polyethylene resin layer 15 is injection-molded on an outside face provided with a recessed and projecting part 11 and is integrally formed in an adapter 30. An outside face of the resin layer 15 is provided in the same dimension as an outside dimension of a polyethylene pipe 33 to be connected. On an inside face, a packing mounting part having a tapered inside face 12, a parallel inside face 13 and a female screw 14 at a tip part are provided and parts for fixing for sealing and fixing to the steel pipe 31 are mounted. In the tapered inside surface 12, a rubber packing 20, a metallic collar 22 having a tapered inside surface 21, a metallic lock ring 24 which is abutted on the tapered inside surface 21 and reduces in diameter and a pressing ring 25 screwed into the female screw 14 are successively provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel pipe connecting adapter which is particularly useful for connecting a steel pipe to an electrofusion joint for connecting a polyethylene pipe.

[0002]

2. Description of the Related Art Conventionally, there is a joint for connecting a polyethylene pipe and a steel pipe as shown in FIG. 3 disclosed in Japanese Patent Application Laid-Open No. 9-170694. In this case, an electrofusion joint 1 is formed integrally with a joint fitting 3 for connecting a steel pipe, and a caulking ring 4 is attached to the outer periphery of the electrofusion joint 1 in which the joint fitting 3 is fitted, thereby removing the joint from the joint fitting 3. This is a joint for connecting a steel pipe and a polyethylene pipe that has been securely fixed.

[0003]

Although this invention was invented as a special joint for connecting a steel pipe and a polyethylene pipe, a fitting part for connecting the joint fitting 3 and the electrofusion joint 1 is always required. Since this fitting portion is inevitably weak within the overall strength, it is reinforced by the caulking ring 4. In order to increase the strength of the fitting portion, it is necessary to increase the length of the fitting portion, and the overall shape becomes large, which causes a problem in handling. In addition, there is a problem that the manufacturing process is complicated because the electrofusion joint 1 must be integrally formed with the joint fitting 3 in a mold during the manufacturing. In addition, when connecting at the piping site, this special steel pipe and polyethylene pipe connection joint must be prepared separately from the usual electric fusion joint for polyethylene pipe connection, and there is also a problem in piping construction. Was. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a steel pipe connection adapter that can be easily and compactly connected to a steel pipe by using an electric fusion joint for connecting a normal polyethylene pipe.

[0004]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a metal fixed ring whose outer surface is coated with a thermoplastic resin that is fused to an electrofusion joint and an outer surface of a connecting steel pipe provided on the inner surface of the fixed ring. An adapter comprising a fixing means for hermetically fixing the steel pipe, wherein the adapter is attached to an outer surface of the steel pipe and connected to the steel pipe.

[0005] In the above, the fixing means includes a packing mounted on a tapered surface provided on the inner surface of the fixed ring to seal the outer surface of the steel pipe, and a collar having a tapered surface on the inner surface and pressing an end of the packing. A lock ring that is inserted into the tapered surface of the collar to reduce the diameter and lock the outer surface of the steel pipe; and a pressing ring that locks to the fixed ring and presses the lock ring toward the collar. This is a steel pipe connection adapter connected by a fusion joint. In the above, the thermoplastic resin covering the outer surface of the stationary ring is a steel pipe connecting adapter connected by an electric fusion joint, which is hermetically integrated with the outer surface of the stationary ring.

[0006]

According to the present invention having the above-mentioned construction, the adapter is coated with a thermoplastic resin on the outer surface, and the inner surface is provided with means for sealing and fixing to the steel pipe. Fix the adapter, insert the steel pipe with the adapter into the polyethylene pipe and the electric fusion joint for connection, and apply electricity to the heating wire of the joint in the same way as normal electric fusion, so that the thermoplastic resin on the outer surface of the adapter is Electrofusion is performed integrally with the joint, and the steel pipe can be connected to the electrofusion joint. Therefore, the polyethylene pipe and the steel pipe can be easily connected by the polyethylene pipe connecting electric fusion joint.

The fixing ring is made of metal and provided with fixing means on the inner surface. When the locking ring is pushed by a pressing ring, the diameter of the locking ring is reduced on the tapered inner surface of the collar, and the fixing ring is engaged with the outer surface of the steel pipe. The collar presses the packing against the tapered inner surface of the stationary ring to hermetically seal between the outer surface of the steel pipe and the inner surface of the stationary ring. A thermoplastic resin coating is provided on the outer surface of the stationary ring, and the resin coating layer is hermetically integrated with the outer surface of the stationary ring, and the resin coating layer is fused in the electrofusion joint. The steel pipe is hermetically connected via the packing of the adapter, the fixed ring, and the resin coating layer.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a state in which a steel pipe 31 and an electric fusion joint 32 are connected using an adapter 30 according to one embodiment of the present invention. In the figure, a stationary ring 10 is made of steel,
The polyethylene resin layer 15 is integrally formed by injection molding on the outer surface on which the substrate 1 is provided. In order to increase the adhesion strength between the stationary ring 10 and the resin layer 15, the outer surface of the stationary ring 10 is subjected to a primer treatment before injection molding. The outer surface of the resin layer 15 is provided with the same size as the outer diameter of a polyethylene pipe connected by a normal electric fusion joint. The inner surface is provided with a packing mounting portion having a tapered inner surface 12, a parallel inner surface 13, and a female screw 14 provided at an end, and a fixing part for hermetically fixing to a steel pipe 31 is mounted. A rubber packing 20 is provided in the tapered inner surface 12, and then an annular collar 22 made of metal and having a tapered inner surface 21.
Then, a metal lock ring 24, which is partially cut off on the circumference and abuts against the tapered inner surface 21 of the collar 22 and is reduced in diameter, is fastened with a pressing ring 25 which is screwed into the female screw 14 of the fixed ring 10. It is.

The pressing wheel 25 has small screws 26 at a plurality of locations on the circumference.
When the small screw 26 is tightened, the end of the lock ring 24 is pressed to reduce the diameter of the lock ring 24, and the biting teeth 26 on the inner surface are locked to the outer surface of the steel pipe 31. When the lock ring 24 is pressed, the collar 22 is pressed.
The packing 20 is pressed by the tapered inner surface 12 of the fixed ring 10 via the through hole, and the packing 20 is compressed, thereby hermetically sealing the gap with the outer surface of the steel pipe 31. With the adapter 30 sealed and fixed to the end outer surface of the steel pipe 31 as described above, the adapter 30 is inserted into a usual resin tube connecting electrofusion joint 32 and electrofused. The polyethylene resin layer 15 of the stationary ring 10 is provided in a thickness necessary for fusion, so that heat generated when the resin layer 15 is fused during electric fusion does not adversely affect the packing 20. Since a normal polyethylene pipe can be easily connected to the other end of the electrofusion joint, the steel pipe 30 is a polyethylene pipe 33.
And can be easily connected using a normal electric fusion joint. Therefore, there is no need to prepare a special joint for connecting a special steel pipe and a polyethylene pipe, and the steel pipe 31 and the polyethylene pipe 33 can be easily prepared.
And plumbing.

[0010]

As described above, the steel pipe connecting adapter for connection by the electric fusion joint of the present invention can be used in a usual manner by simply attaching the adapter to the steel pipe without preparing a special dedicated joint. Can be connected with an electric fusion joint. Therefore, piping work can be easily performed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a connection state using a steel pipe connection adapter showing one embodiment of the present invention.

FIG. 2 is a front view showing the lock ring of FIG. 1;

FIG. 3 is a partial sectional view showing a conventional plug-in type pipe joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Fixed ring 11 Concavo-convex part 12 Tapered inner surface 13 Parallel inner surface 14 Female screw 15 Resin layer 20 Rubber packing 21 Tapered inner surface 22 Collar 24 Lock ring 25 Press ring 26 Small screw 30 Adapter 31 Steel pipe 32 Electric fusion joint 33 Polyethylene pipe

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Keio Akiyama 120 Shimo, Fussa-shi, Tokyo Yoko Engineering Co., Ltd. F-term (reference) 3H019 GA02

Claims (3)

[Claims] 1. An adapter comprising: a metal stationary ring coated on the outer surface with a thermoplastic resin which is fused to an electrofusion joint; and a fixing means for hermetically fixing the outer surface of a connecting steel pipe provided on the inner surface of the stationary ring. An adapter for steel pipe connection connected by an electric fusion joint, wherein the adapter is attached to an outer surface of the steel pipe for connection. 2. A fixing device comprising: a packing mounted on a tapered surface provided on an inner surface of the fixed ring to seal an outer surface of a steel pipe provided inside; and a collar having a tapered surface on an inner surface and pressing an end of the packing. A lock ring that is inserted into the tapered surface of the collar to reduce the diameter and lock the outer surface of the steel pipe; and a pressing ring that locks to the fixed ring and presses the lock ring toward the collar. Item 7. An adapter for connecting steel pipes connected by the electric fusion joint according to Item 1. 3. The electrofusion joint according to claim 1, wherein the thermoplastic resin covering the outer surface of the stationary ring is hermetically integrated with the outer surface of the stationary ring. Adapter for connecting steel pipes.