JPH0228037B2 - BOSHOKUKANTSUGITE - 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. 3), 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 the 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 cylinder body 2, causing the cylinder to leak. 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 metal pipe fitting main body has a concave groove along the circumferential direction on the inner circumferential surface of the deep part, and the groove is provided with a female thread part continuous to the female thread part on the inner circumferential surface of the end part, and A cylindrical body made of synthetic resin, which has an annular groove on its inner surface and a convex strip along the circumferential direction, is fitted by injection molding, and the outer diameter is approximately the same as the inner diameter of the tube to be connected. The present invention relates to a corrosion-resistant pipe joint, characterized in that a synthetic resin short pipe is assembled by fitting an annular protrusion provided substantially in the center of the short pipe into the annular groove.

(Function) In the corrosion-resistant pipe joint of the present invention, packing can be built into the deep part of the outer periphery of the assembled short synthetic resin pipe, and the internal thread of the synthetic resin cylindrical body and the male thread of the internally coated steel pipe are connected. A three-sided sealed structure can be adopted: a screwing surface, a close contact surface between the synthetic resin short tube and the inner coating layer of the inner coated steel tube, and a close contact surface between the packing and the end surface of the inner coated steel tube.

Furthermore, the presence of the synthetic resin short pipe prevents the packing from bulging into the inside of the pipe.

Furthermore, since the synthetic resin short tube is assembled by fitting its annular protrusion into the annular groove of the synthetic resin cylindrical body, it is rotatable about the axial direction.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing one embodiment of the corrosion-resistant pipe joint 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 protrusion 122 is provided in the inner part thereof along the circumferential direction. This ridge 122
An annular groove 123 is provided along the circumferential direction on the inner peripheral surface.

The synthetic resin cylindrical body 12 is shaped by injection molding a synthetic resin into the groove 112 of the metal pipe joint body 11. Reference numeral 13 is a short tube made of synthetic resin, which has an outer diameter approximately the same as the inner diameter of the tube to be connected, and has an annular shape of the synthetic resin cylindrical body 12 on the outer circumferential surface of the approximately central portion thereof. Groove 123
An annular protrusion 131 having a symbol 131 is provided.

The synthetic resin short pipe 13 is inserted into the metal pipe joint body 11 in which the synthetic resin cylindrical body 12 is provided in the groove 112 by injection molding, and the synthetic resin cylindrical body 12 is inserted into the metal pipe joint body 11.
A corrosion-resistant pipe joint is assembled by fitting the annular protrusion 131 of the synthetic resin short pipe 13 into the annular groove 123 of the pipe.

Figure 2 shows the above-mentioned corrosion-resistant pipe joint with inner-coated steel pipe 1.
FIG. 4 is a sectional view for explaining the process of connecting 4. When the inner-coated steel pipe 14 is screwed into this corrosion-resistant pipe joint, the tip of the inner-coated layer 141 is locked to the end of the synthetic resin short pipe 13, and when the inner-coated steel pipe 14 is screwed further, the synthetic resin Short tube 13
will also rotate in sync with that rotation. The joint surface between the annular groove 123 and the annular protrusion 131 serves as a bearing surface for the rotation.

In this way, the inner-coated steel pipe 14 is formed into a synthetic resin short pipe 1.
While rotating 3, it advances deep inside and is tightened via packing 15.

(Effects of the Invention) By having the above-described structure of the corrosion-resistant pipe joint of the present invention, when the coated steel pipe is screwed into the female threaded part of the synthetic resin cylindrical body, this threaded part and the inner coating layer are connected to the synthetic resin short pipe. Since it is sealed in close contact with the pipe,
Leakage of the internal fluid can be prevented, and the internal fluid will not seep into the pipe joint body and cause corrosion.

In addition, when the packing is applied to the inner part of the outer periphery of the synthetic resin short pipe and is tightened through the packing between the end face of the inner-coated steel pipe to be connected, the end face of the inner-coated steel pipe is also sealed, resulting in a three-sided seal. structure, it is possible to more completely prevent internal fluid from seeping out. In this case, the presence of the synthetic resin short pipe prevents the compressed packing from bulging into the pipe, so that the flow of the internal fluid is not impaired. Furthermore, since the synthetic resin short tube is rotatably assembled, the short synthetic resin tube and the coating layer near the end of the steel tube are less likely to be damaged when screwing in the internally coated steel tube.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is a sectional view illustrating how the embodiment shown in FIG. 1 is used, and FIG. 3 is a sectional view showing a conventional one. 11...Metal pipe joint body, 12...Synthetic resin cylindrical body, 13...Synthetic resin short pipe, 111,1
21...Female thread portion, 112...Concave groove, 122...
Convex line, 123... Annular concave groove, 131... Annular convex line.

Claims (1)

[Claims] 1 A female threaded portion is provided on the inner circumferential surface of the end portion, and a groove is provided on the inner circumferential surface of the end portion of the main body of the metal pipe fitting body, and the groove is provided with a groove along the circumferential direction on the inner circumferential surface of the end portion. A cylindrical body made of synthetic resin is fitted by injection molding, and is provided with a female threaded portion, and a convex strip having an annular groove on the inner circumferential surface of the deep inner circumferential surface. Further, a short synthetic resin tube having an outer diameter that is approximately the same as the inner diameter of the tube to be connected is assembled by fitting an annular protrusion provided approximately at the center of the tube into the annular groove. Corrosion-resistant pipe fittings featuring: