JPH07305791A - Pipe end corrosion protected coupling - Google Patents

Abstract

PURPOSE:To provide a pipe end corrosion-protected coupling which is constituted to reliably prevent the generation of rusty water and prevent pollution of fluid in a pipe. CONSTITUTION:A male screw 31 is formed on the end part of a lining metallic pipe B and a diameter expansion part 32 having an inside diameter approximately equal to the outside diameter of the cylindrical part 21 of a pipe coupling A is produced by cutting the inner surface of the end part of a synthetic resin layer 4 with which the inner peripheral surface of the metallic pipe B is covered. When the male screw 31 of the lining metallic pipe 3 is joined in a screwed-in state with the female screw 11 of the pipe coupling A, a cylindrical part 21 is fitted in the diameter expansion part 32 and a rubber packing 23 mounted on the tip of the cylindrical part 21 is brought into contact with a stepped part 33 on the deep side of the diameter expansion part 32. This constitution prevents the generation of rusty water and pollution of fluid in a pipe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe end anti-corrosion joint capable of reliably preventing the generation of red water by water-tightly connecting a lining metal pipe to a pipe joint whose inner peripheral surface is covered with a synthetic resin layer.

[0002]

2. Description of the Related Art As a conventional pipe end anticorrosion joint, the one shown in FIG. 3 in a sectional view is known. In this pipe end anticorrosion joint, the inner peripheral surface of a metal joint 1 having an internal thread 11 at its end is covered with a synthetic resin layer 2 excluding the internal thread 11, and extends from the synthetic resin layer 2 to form a tubular shape on the opening side. The inner periphery of the metal pipe 3 and the pipe joint in which the portion 21 is provided, a gap 22 having a predetermined width is provided between the outer peripheral surface of the tubular portion 21 and the female screw 11, and a recess 220 is provided in the inner portion thereof. A cylindrical portion 2 of a pipe joint, which is composed of a lining metal pipe whose surface is covered with a synthetic resin layer 4
The adhesive 5 was interposed between the outer peripheral surface of No. 1 and the inner peripheral surface of the end of the lining metal pipe to connect them.

[0003]

However, in the case of this conventional joint, the adhesive 5 applied to the outer peripheral surface of the tubular portion 21 sometimes protruded to the inner peripheral surface of the lining metal pipe. That is, the end of the lining metal pipe is connected to the gap 22 of the pipe joint.
When it is inserted and screwed in, the excess adhesive 5 moves to the inner side of the gap 22 and fills the inside of the hollow 220, and when the lining metal pipe is further screwed in strongly, the adhesive 5 is pressed against the pipe end surface.
Protrudes from between the tubular portion 21 and the inner peripheral surface of the end portion of the lining metal pipe. Then, the fluid in the pipe may be contaminated by the solvent or the like oozing out from the adhesive 5.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. The pipe joint and the lining metal pipe are watertightly connected to each other via a rubber packing to reliably prevent the generation of red water and contaminate the fluid in the pipe. The present invention provides a pipe end anti-corrosion joint that does not have any problems.

[0005]

A pipe end anticorrosion joint of the present invention is a metal joint having an internal thread at its end, the inner peripheral surface of which is covered with a synthetic resin layer excluding the internal thread, and which extends from the synthetic resin layer. And a lining metal in which a cylindrical portion is provided on the opening side and a gap of a predetermined width is provided between the outer peripheral surface of the cylindrical portion and the female screw, and the inner peripheral surface of the metal pipe is covered with a synthetic resin layer. A pipe and a male screw is provided at the end of the lining metal pipe, and the inner surface of the end of the synthetic resin layer covering the inner peripheral surface of the metal pipe is cut out to have an inner diameter approximately equal to the outer diameter of the tubular portion. The expanded diameter portion having is provided. Then, when the male thread of the lining metal pipe is screwed into the female thread of the pipe joint, the tubular portion is fitted into the expanded diameter portion, and the rubber packing attached to the tip of the tubular portion is the step portion on the inner side of the expanded diameter portion. It is characterized in that it comes into contact with.

[0006]

With the above construction, when the male thread of the lining metal pipe is screwed into the female thread of the pipe joint, the tubular portion is fitted into the expanded diameter portion and the rubber packing attached to the tip of the tubular portion is expanded. It contacts the step on the inner side of the diameter part and joins in a watertight manner.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is a sectional view of a pipe end anticorrosion joint showing an embodiment of the present invention, and FIG. 2 is a sectional view of an essential part of the joint shown in FIG.
Reference numeral A in the drawing is a pipe joint, and B is a lining metal pipe.

In the pipe joint A, the inner peripheral surface of a metal joint 1 having internal threads 11 at both ends is integrally covered with a synthetic resin layer 2 such as vinyl chloride resin except the internal threads 11. The tubular portion 21 is extended and provided on the opening side. An annular groove is provided at the tip of the tubular portion 21, and a ring-shaped rubber packing 23 is attached to the groove. The shape of the rubber packing 23 is not limited to that shown in the figure, but may be any suitable shape, and the inside thereof may be hollow. Further, a gap 22 having a predetermined width is provided between the outer peripheral surface of the tubular portion 21 and the internal thread 11.
The end of the lining metal tube B can be fitted into the gap 22.

The lining metal pipe B is formed by coating the inner peripheral surface of a metal pipe 3 such as a cast iron pipe or a steel pipe with a synthetic resin layer 4 such as vinyl chloride resin, and cutting the inner surface of the end of the synthetic resin layer 4. The enlarged diameter portion 32 having an inner diameter substantially equal to the outer diameter of the tubular portion 21 is provided. Also, the axial length L of the expanded diameter portion 32
Can be appropriately determined depending on the screwing depth of the lining metal pipe B and the axial length of the tubular portion 21 of the pipe joint A. In short, when the female screw 11 of the pipe joint A is screwed with the male screw 31 provided at the end of the lining metal pipe B, the tubular portion 21 of the pipe joint A is fitted into the expanded diameter portion 32 and the tubular portion The rubber packing 23 attached to the tip of the elastic member 21 may be elastically brought into contact with the step portion 33 on the inner side of the expanded diameter portion 32 so as to ensure watertightness.

[0010]

As described in detail above, in the pipe end anticorrosion joint of the present invention, when the lining metal pipe is screwed into the pipe joint, the tubular portion of the pipe joint is expanded on the inner surface of the end of the lining metal pipe. The rubber packing fitted on the tip of the tubular part elastically abuts the step part on the far side of the expanded part while ensuring watertightness as it fits into the diameter part, corroding the metal part and red water. Does not occur. Further, since the pipe end anticorrosion joint of the present invention does not use an adhesive from which a solvent or the like seeps out, it does not contaminate the fluid in the pipe.

[Brief description of drawings]

FIG. 1 is a sectional view of a pipe end anticorrosion joint showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts of the pipe end anticorrosion joint shown in FIG.

FIG. 3 is a cross-sectional view showing a main part of a conventional joint.

[Explanation of symbols]

 A Pipe joint B Lining metal pipe 1 Metal joint 2 Synthetic resin layer 3 Metal pipe 4 Synthetic resin layer 11 Female screw 21 Cylindrical part 22 Gap 23 Rubber packing 31 Male screw 32 Expanding part 33 Step part

Claims (1)

[Claims] 1. A metal joint (1) having an internal thread (11) at an end thereof is coated with a synthetic resin layer (2) excluding the internal thread (11), and from the synthetic resin layer (2). A tubular portion (21) is provided extending toward the opening side and the tubular portion (21) is provided.
A pipe joint (A) having a gap (22) of a predetermined width between the outer peripheral surface of the metal pipe and the female screw (11), and a lining in which the inner peripheral surface of the metal pipe (3) is covered with a synthetic resin layer (4). An end portion of a synthetic resin layer (4) which is composed of a metal pipe (B), is provided with an external thread (31) at the end of the lining metal pipe (B), and covers the inner peripheral surface of the metal pipe (3). The inner surface is cut out to provide an enlarged diameter portion (32) having an inner diameter substantially equal to the outer diameter of the cylindrical portion (21), and the female screw (1) of the pipe joint (A) is provided.
When the male screw (31) of the lining metal pipe (B) is screwed into 1), the tubular portion (21) is fitted into the expanded diameter portion (32) and is attached to the tip of the tubular portion (21). A pipe end anticorrosion joint, characterized in that a rubber packing (23) comes into contact with a step portion (33) on the inner side of the expanded diameter portion (32).