JPS6125957B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a corrosion-resistant pipe joint suitable for use in water piping.

(Prior art) Conventionally, as corrosion-resistant pipe joints, for example,
As described in Publication No. 16215 (see Fig. 8), it consists of a socket body 1 made of vinyl chloride and a cylindrical body 2 made of corrosion-resistant aluminum, and the outer circumference of the socket body 1 is formed at the center inner circumference of the cylinder 2. It fits into the annular recess 3 and its axial movement is prevented, and its inner circumferential surface becomes larger in diameter from the annular protrusion 5 formed at the center inner circumference toward the mouth end. It has been proposed that the pipe is formed with tapered surfaces 4, 4, so that a double-walled vinyl chloride pipe portion is tightly fitted onto these surfaces.

(Problems to be Solved by the Invention) However, in the conventional socket body 1 as described above, the fitting between the socket body 1 and the double pipe is not sufficient, and the internal fluid seeps into the cylindrical body 2, causing the cylindrical A drawback was that the body 2 could not be sufficiently protected against corrosion.

(Means for Solving the Problems) The present invention has been made for the purpose of eliminating the conventional drawbacks as described above, and its gist is that a female threaded portion is provided on the inner circumferential surface of the end portion, and A cylindrical body made of synthetic resin, which has a concave groove along the circumferential direction on the inner circumferential surface of the inner part of the metal, and a female threaded part that is continuous with the female threaded part on the inner circumferential surface of the end part of the main body of the metal pipe joint. A corrosion-resistant pipe joint in which a

(Function) As mentioned above, there is a synthetic resin female threaded part that is fitted continuously to the metal female thread, and the inner surface of the steel pipe coated with synthetic resin is screwed up to this synthetic resin female threaded part and sealed between it and the synthetic resin female threaded part. However, the main body of the pipe joint is corroded.

(Example 1) Hereinafter, the present invention will be explained with reference to examples shown in the drawings.
FIG. 1 is a sectional view showing one embodiment of the present invention.
Reference numeral 11 denotes a metal pipe joint body, which is provided with internal threads 111, 111 on the inner circumferential surface of both ends thereof, and a wide groove 112 is provided along the circumferential direction on the inner circumferential surface of the deep part thereof.

Reference numeral 12 is a cylindrical body made of synthetic resin, the outer circumferential surface of which has a shape that corresponds to the groove 112 of the metal pipe joint body 11, and female threads 121, 121 on the inner circumferential surface of both ends.
is the female threaded portion 111, 11 of the metal pipe joint body 11.
1, and a concave groove 122 is provided in the inner part thereof along the circumferential direction.

A synthetic resin cylindrical body 12 is fitted into a groove 112 of a metal pipe joint body 11 by injection molding to form a corrosion-resistant pipe joint.

(Effect of the invention) With the above structure, when the inner surface of the steel pipe coated with synthetic resin is screwed in to the synthetic resin female thread, a seal is formed between the two to prevent leakage of the internal fluid. It will not seep into the pipe fitting body and cause corrosion.

(Embodiment 2) FIG. 2 is a sectional view showing another embodiment of the present invention.

Reference numeral 15 denotes a metal pipe joint body, which has female screw portions 151, 151 provided on the inner circumferential surface of both ends, and a groove 152 provided along the circumferential direction on the inner circumferential surface of the deep part thereof.

Reference numeral 16 is a cylindrical body made of synthetic resin, the outer peripheral surface of which has a shape that corresponds to the concave groove 152 of the metal pipe joint body 15, and female threads 161, 161 on the inner peripheral surface of both ends.
is provided, and a protruding strip 16 is provided along the circumferential direction at the inner part thereof.
2 is provided.

A synthetic resin cylindrical body 16 is fitted into the groove 152 of the metal pipe joint body 15 by injection molding to form a corrosion-resistant pipe joint.

If the synthetic resin cylindrical body 16 is provided with a convex strip 162 along the circumferential direction on the inner circumferential surface of the inner part as in this embodiment, as shown in FIG. A short cylindrical body 18 with a flange is placed between the end face of
This is preferable because it can be tightened through the packing 19 and a connection with excellent watertightness can be made.

(Embodiment 3) FIG. 4 is a sectional view showing another embodiment of the present invention.

The protruding stripes 162' of the synthetic resin cylindrical body 16' are provided with 163' and 16' extending toward the end of the metal pipe joint body 15'.
3' is provided integrally.

As in this embodiment, if the projecting strips 162' of the synthetic resin cylindrical body 16' are integrally provided with projecting pieces 163', 163' toward the end of the metal pipe joint body 15', When connecting inner-coated steel pipes through packing, a short flanged tube 1 as shown in Fig. 3 is used.
8 is unnecessary, and the connection can be made with the core exposed, which is more preferable than when using the flanged short tube 18.

(Embodiment 4) FIG. 5 is a sectional view showing another embodiment of the present invention.

As in the embodiment shown in FIG. 4, protruding pieces 163', 16
3' is not integrally provided, and the metal pipe joint body 1 is attached to the protrusion 162'' of the synthetic resin cylindrical body 16''.
A short cylindrical body 20 having protruding pieces 201, 201 toward the 5'' end is provided separately.

If the short cylindrical body 20 having the protruding pieces 201, 201 is provided separately as in this embodiment, if the protruding pieces 201, 201 are damaged, only the short cylindrical body 20 needs to be replaced. suitable.

(Embodiment 5) FIG. 6 is a sectional view showing another embodiment of the present invention.

Female threaded portions 211, 21 of synthetic resin cylindrical body 21
A groove 2 is formed along the circumferential direction between the groove 1 and the protrusion 212.
13,213 are provided.

If grooves 213, 213 are provided along the circumferential direction between the female threaded portions 211, 211 of the synthetic resin cylindrical body 21 and the convex strip 212 as in this embodiment, FIG. As shown, when the flanged short cylinder body 18 and the packing 19 are interposed between the end face of the inner-coated steel pipe 17 to be connected and tightened, the packing 18 does not fit into the groove 213 even if there are variations in the threads.
It deforms in such a way that it bulges inward, making it possible to make a connection with excellent watertightness.

[Brief explanation of the drawing]

1 and 2 are sectional views showing embodiments of the present invention, FIG. 3 is a sectional view illustrating how the embodiment shown in FIG. 2 is used, and FIGS. FIG. 7 is a sectional view illustrating the usage of the embodiment shown in FIG. 6, and FIG. 8 is a sectional view showing a conventional one. Explanation of symbols, 11, 15, 15', 15''...Metal pipe fitting body, 12, 16, 16', 16''...
Synthetic resin cylindrical body, 111, 151... Female threaded part, 112... Concave groove, 121, 161... Female threaded part, 122, 213... Concave groove, 162, 16
2', 162'', 212...Convex strip, 163', 20
1...Protruding piece.

Claims (1)

[Scope of Claims] 1. A metal pipe fitting main body has a female threaded portion on the inner circumferential surface of the end portion, and a groove is provided along the circumferential direction on the deep inner circumferential surface of the metal pipe joint body. A corrosion-resistant pipe joint in which a synthetic resin cylindrical body having a female threaded portion continuous with the female threaded portion is fitted into the tubular body. 2. The corrosion-resistant pipe joint according to claim 1, wherein the synthetic resin cylindrical body is provided with protrusions along the circumferential direction on the inner circumferential surface of the deep part. 3. The corrosion-resistant pipe joint according to claim 2, wherein the protruding strip is provided with a protruding piece toward the end of the metal pipe joint main body. 4. The corrosion-resistant pipe joint according to claim 3, wherein the protruding piece is provided separately. 5. The corrosion-resistant pipe according to claim 2, 3, or 4, wherein the synthetic resin cylindrical body is provided with a groove along the circumferential direction between the female threaded portion and the convex strip. Fittings. 6. Corrosion prevention according to claim 1, 2, 3, 4, or 5, wherein the synthetic resin cylindrical body is fitted into the metal pipe joint body by injection molding. pipe fittings.