JPS5931991Y2 - Internally coated steel pipe connections - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a joint for internally coated steel pipes.

Conventionally, when connecting internally coated steel pipes, in order to protect the pipe end surface from corrosion and also prevent liquid leakage from the joint, a joint pipe was interposed and a tapered thread was used, as disclosed in Japanese Utility Model Publication No. 45-17969, for example. In a joint for an internally coated steel pipe that is screwed into the pipe, a covering ring made of a heat-resistant or corrosion-resistant metal thin plate and having an L-shaped cross section that extends closely from the end face to the inner surface of the pipe is bonded to the inner-coated steel pipe using a heat-resistant or corrosion-resistant adhesive. , and a structure in which the outer diameter of the covering ring is set to the diameter of the groove of the basic diameter of the internally coated steel pipe, and the covering ring is bonded at the outer edge between the thread of the internally coated steel pipe and the thread of the joint pipe. is proposed.

However, when the end face of the internally coated steel pipe has an uneven surface or is cut diagonally, even if a cover ring made of a thin metal plate is glued from the end face to the inner surface, the joint will not work. When connected to a pipe, there may be a gap between the pipe end face and the covering ring, making it impossible to sufficiently prevent corrosion between the pipe end face and the pipe end face, and liquid may leak from the joint because it is tightened unevenly. There was a drawback that this occurred.

The present invention has been developed with the aim of eliminating the drawbacks such as sloping. At the connection portion screwed into the tapered salt thread portion of the joint, an annular elastic body is brought into contact with the end face of the inner-coated steel pipe, so as to cover the end face of the elastic body and the inner peripheral surface of the end of the inner-coated steel pipe. It exists at the connection part of an inner-coated steel pipe which is crowned with a short flanged tube.

Hereinafter, the present invention will be explained with reference to an embodiment of the drawings.

Reference numeral 1 denotes an inner-coated steel pipe, in which a coating layer 12 made of thermoplastic resin or the like is provided on the inner surface of the steel pipe 11, and a tapered salt threaded portion 13 is provided on the outer peripheral surface of the pipe end.

Reference numeral 2 denotes a pipe joint, and a tapered salt threaded portion 21 is provided on the inner circumferential surface of the end thereof.

3 is an annular elastic body.

4 is a short cylinder with a flange, and a flange 41 having an outer diameter approximately the same as the outer diameter of the annular elastic body 3 is attached to one end of a cylindrical body 42 having an outer diameter that is the same as or slightly smaller than the diameter of the inner-coated steel pipe 1. It is made of synthetic resin, such as hard vinyl chloride resin, to provide corrosion resistance and sealing performance.

An annular elastic body 3 is brought into contact with the end surface of the internally coated steel pipe 1 on which the tapered salt thread portion 13 is provided so as to cover the joint between the steel pipe 11 and the coating layer 12 .

A short flanged tube 4 is crowned so as to cover the end surface of the elastic body 3 and the inner circumferential surface of the end of the internally coated steel tube 1.

In this manner, with the flanged short tube 4 capped on the end surface of the inner-coated steel pipe 1 via the elastic body 3, the tapered salt threaded portion 13 of the pipe end is connected to the tapered salt threaded portion 21 of the pipe fitting 2. When screwed together and tightened, first, the outer edge of the collar 41 of the short flanged tube 4 comes into contact with the tapered salt threaded portion 21 of the pipe joint 2 to partially form a sealing surface, and the short flanged tube 4 becomes annular. The elastic body 3 is pressed against the end face of the internally coated steel pipe 1 to seal the end face from the outside and prevent corrosion, and also bulges between the tapered salt seam part 13 and the tapered salt thread part 41 to create a space between them. A secondary sealing surface is formed.

As shown above, in the present invention, an annular elastic body is brought into contact with the end face of an inner-coated steel pipe, and the collar body is shortened so as to integrally cover the end face on the elastic body and the inner peripheral surface of the end of the inner-coated steel pipe. The tube is crowned and the end of the inner-coated steel pipe is screwed into the pipe joint, so even if the end face of the inner-coated steel pipe has an uneven surface or is cut diagonally, the elastic body will protect the end face. The end face is completely protected against corrosion, and the connection between the internally coated steel pipe and the pipe fitting is double-sealed by the collar of the flanged short tube and the elastic body bulged by the pressure of the flanged short tube. The seal is completely sealed, and it can be easily and easily installed on-site without requiring advanced skills.

[Brief explanation of the drawing]

FIG. 1 is a partially longitudinal front view of an embodiment of the present invention, and FIG. 2 is a partially longitudinal front view showing an enlarged main part of FIG. Explanation of symbols 1... Internally coated steel pipe, 2...
... Pipe joint, 3 ... Annular elastic body, 4 ...
・Short tube with flange, 13...Tapered salt thread part, 21
...Tapered salt thread part.

Claims (1)

[Scope of utility model registration request] 1. A tapered salt thread is provided on the outer circumferential surface of the end of the internally coated steel pipe, and the threaded part is screwed into the tapered salt thread of the pipe joint. A connecting portion of an internally coated steel pipe, in which a short tube with a flange is crowned to cover the end face of the elastic body and the inner circumferential surface of the end of the internally coated steel pipe. 2. The connecting portion of an internally coated steel pipe according to claim 1, wherein the flanged short tube is made of synthetic resin.