JPS5832069Y2 - pipe fittings - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pipe joint for connecting internally coated steel pipes.

Conventionally, when connecting internally coated steel pipes, in order to protect the end faces of the pipes from corrosion and prevent liquid from leaking from the joints, the internal pipes were sandwiched between iron gassho lids, as disclosed in Japanese Utility Model Publication No. 37-18144, for example. It has been proposed that a backing is fitted into the interior of a joint pipe joint that is fixed and integrated so that the joint pipe can be inserted into the threaded thread.

However, with the diagonal type, even if you try to tighten the joint pipe to the joint pipe joint, the backing will be pressed between the end of the internal cylinder and the end of the joint pipe, and the compressed backing will not fit into the joint pipe joint. It bulges inward at the joint between the joint pipe and the joint pipe and easily falls off into the pipe, and the joint pipe cannot be sufficiently tightened through the backing to the joint pipe fitting to prevent the backing from falling off. As a result, there has been a drawback in that it is not possible to sufficiently prevent corrosion of the pipe end face of the joint pipe and prevent liquid leakage from the joint.

As an attempt to eliminate this drawback,
Publication No. 9714 describes that a protrusion forming an annular groove with a deep end is provided in the inner part of the female thread part of the pipe joint, and by inserting the backing into this annular groove, the backing is prevented from falling off. However, if the accuracy of the female thread of the pipe joint and the male thread of the joint pipe is poor, the backing may be compressed excessively into the annular groove and damaged, or conversely, sealing may not be possible.

The present invention was made in an attempt to eliminate the conventional drawbacks such as sloping, and to provide a product that does not cause the backing to fall off and can provide a good seal without damaging the backing even if the degree of screwing changes. The gist is that a female thread is provided on the inner circumferential surface of the opening end, a groove is provided along the circumferential direction on the inner circumferential surface of the deep part, and a jetty is provided along the circumferential direction in the deep part. One end of the short cylindrical body is brought into contact with the jetty side surface of the pipe fitting main body so as to have the same axis, and a cylindrical annular backing is installed between the short cylindrical body and the pipe fitting main body, and the annular A notch is provided along the circumferential direction on the outer circumferential surface of the backing, the notch is engaged with a corner of the side wall of the groove and the female thread, and there is a space between the groove and the annular backing. It exists in a pipe joint in which an annular space is formed.

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

Reference numeral 1 denotes a pipe joint main body, which has a tapered female thread 11 on the inner peripheral surface of its end, a groove 12 along the circumferential direction on the inner peripheral surface of the deep part, and A jetty 13 is provided along the direction, and the surfaces of the groove 12 and the jetty 13 are coated with an anticorrosion coating.

2 is a short cylinder.

The short cylindrical body 2 is made of a material that does not deform even when an external force is applied and is corrosion-resistant, such as a stainless steel pipe. Its inner diameter is approximately the same as the inner diameter of the jetty 13 of the pipe fitting body 1, and its length is the same as that of the pipe fitting body 1. It is made longer than the width of the groove 12 of the main body 1.

This short cylindrical body 2 is brought into contact with one end of the side surface of the jetty 13 of the pipe joint body 1 so as to have the same axis.

3 is a cylindrical annular backing made of an elastic material.

This material may be natural or synthetic rubber, but may be an elastic body that expands in volume when it comes in contact with water, such as a blend of rubber and a polyurethane elastomer or prepolymer that expands when it comes in contact with water. is used.

The width of the annular backing 3 is slightly longer than the width of the groove 12 of the pipe joint body 1 and slightly shorter than the length of the short cylindrical body 2,
A notch 31 is provided along the circumferential direction on the outer circumferential surface, and the notch 31 can be engaged with a corner between the side wall of the groove 12 and the female threaded portion 11 .

With the notch 31 of this annular backing 3 as a boundary, one side has a width that is almost the same as the width of the groove 12 and has a smaller diameter than the diameter of the groove, and the other side has a thickness that is smaller than that of the short cylindrical body 2 and the tapered female thread. It is said to be slightly larger than the interval of 11.

This annular backing 3 is attached between the short cylindrical body 2 and the pipe joint body 1 with the notch 31 engaged with the corner of the groove 12.

To attach the short cylindrical body 2 and the annular backing 3 to the pipe fitting body 1, for example, attach the annular backing 3 to the outer periphery of the short cylindrical body 2, insert it into the pipe fitting body 1, and cut it. When the notch 31 is engaged with the corner of the side wall of the groove 12 and the female threaded part 11, a part of the annular backing 3 is pressed between the tapered female threaded part 11 and the short cylinder 2, and the short cylinder is One end surface of each of the body 2 and the annular backing 3 is attached to the pipe joint body 1.
The pipe joint of the present invention is formed by abutting and fixing on the side surface of the jetty 13 (see Fig. 1).

As in the diagonal embodiment, the annular backing 3 is attached to the pipe joint body 1.
If the short cylinder body 2 and the annular backing 3 attached to its outer periphery are attached in a pressed state between the tapered female threaded part 11 and the short cylinder body 2, the short cylinder body 2 and the annular backing 3 attached to its outer periphery are coaxial with the jetty 13 of the pipe joint body 1. It is attached so that it has.

Further, as shown in FIG. 2, in the case where an annular notch 131 is provided on the inner circumference of the side surface of the jetty 13 and one end of the short cylinder 2 is fitted into the notch 131, , short cylinder 2
can be securely fixed at a predetermined position on the jetty 13.

Further, it is preferable to push the short cylinder 2 into a notch 131 with a tapered surface whose diameter gradually decreases toward the inner part, since it can be more securely fixed.

When one end of the short cylindrical body 2 is fitted into the notch 131 of the jetty 13 in this way, it is not necessary to press the annular backing 3 between the tapered female threaded part 11 of the pipe joint body 1 and the short cylindrical body 2. It does not have to be installed in this condition.

Further, as shown in FIGS. 3 and 4, instead of the short cylindrical body 2 in the slanted embodiment, a short cylindrical body 2' having a flange 21' at one end may be used.

Next, a mode of use of the embodiment of the present invention shown in FIG. 1 will be explained with reference to FIG. 5.

Reference numeral 4 designates an inner-coated steel pipe connected by a pipe joint, and a corrosion-resistant coating layer 42 made of synthetic resin or the like is provided on the inner surface of the steel pipe 41, and a tapered male threaded portion 43 is provided on the outer peripheral surface of the pipe end.

The internally coated steel pipe 4 is attached to the tapered female threaded portion 11 of the pipe joint body 1.
When the tapered male threaded portion 43 of
When tightened further, the annular backing 3 is compressively deformed, but since it is supported by the short cylinder 2, it does not bulge inward, but deforms toward the space of the groove 12, and the outer circumference of the short cylinder 2. It is compressed between the surface and the inner circumferential surface of the concave groove 12, and is effectively compressed by the pipe end surface of the internally coated steel pipe 4, and seals the front side of the threaded portion between the tapered female threaded portion 11 and the tapered salt threaded portion 43. .

The pipe joint of the present invention is constructed in a diagonal manner, and the short cylinder body is provided in the pipe joint body, so that even if the annular backing is pushed by the end surface of the inner-coated steel pipe, it will not fall inward and become recessed. It deforms into a groove, and its repulsive force completely seals the end surface of the inner-coated steel pipe and the threaded part between the female thread of the pipe fitting and the male thread of the inner-coated steel pipe, preventing corrosion and preventing liquid from flowing out from the connection. Leakage can be sufficiently prevented.

In addition, since a groove is provided along the circumferential direction on the inner circumferential surface of the inner part of the female thread, the backing is compressed and deformed into this groove even if the pipe and the fitting become deeply inserted. This prevents excessive compression of the backing, and allows adjustment of compression deformation of the backing in response to changes in screw-in depth due to variations in thread cutting accuracy.

In addition, the notch of the annular backing is locked to the corner of the side wall of the groove and the female thread, so even if exposed to harsh transportation conditions, the short cylinder and the annular rubber ring will not run out or fall off. The connection can be made simply by carving a male thread on the end of the steel pipe and screwing it into the pipe joint of the present invention, in the same way as conventional threaded connections of steel pipes.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view showing an embodiment of the present invention;
4 to 4 are partially cutaway front views showing other embodiments of the present invention, and FIG. 5 is a partially cutaway front view showing how the embodiment of the present invention shown in FIG. 1 is used. FIG. 6 is a partially cutaway front view showing the annular backing used in the embodiments of FIGS. 1 to 4 of the present invention. Explanation of symbols 1...Pipe joint body, 2, 2'...
... Short cylindrical body, 3 ... Annular backing, 11
...Female thread part, 12 ... Concave groove, 13.
... Jetty, 131 ... Notch, 31.
...notch part.

Claims (1)

[Scope of utility model registration request] 1. A jetty side surface of a pipe fitting main body, which has a female thread on the inner peripheral surface of the open end, a recessed groove along the circumferential direction on the inner peripheral surface of the inner part, and a jetty along the circumferential direction in the inner part of the recessed groove. One end of the short cylindrical body is brought into contact with the tube so as to have the same axis, and a cylindrical annular backing is installed between the short cylindrical body and the pipe joint body, and a cylindrical annular backing is attached to the outer circumferential surface of the annular backing in the circumferential direction. A notch is provided along the groove, the notch is engaged with a corner of the side wall of the groove and the female groove, and an annular space is formed between the groove and the annular backing. A pipe fitting. 2. The pipe joint according to claim 1, wherein the annular backing is attached to the female threaded portion of the pipe joint body in a pressed state. 3. The pipe according to claim 1 or 2, wherein an annular notch is provided on the inner circumference of the side surface of the jetty, and one end of the short cylinder is fitted into the notch. Fittings.