JPH0519779U - Pipe fitting - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a pipe joint that can exhibit high sealing performance and corrosion resistance. [Structure] A pipe joint body 2 made of a metal casting having female screw portions 1 and 1 at its ends, a hard plastic layer 4 covering the inner surface of the inner portion of the pipe joint body 2, and a continuous hard plastic layer 4. And substantially cylindrical core portions 5 and 5 made of soft plastic protruding from the core. Predetermined gaps 3 and 3 are provided between the female screw portions 1 and 1 and the substantially cylindrical core portions 5 and 5.
In the connected state of the pipe joint A and the connected pipes 7, 7, the outer peripheral surfaces 9, 9 of the substantially cylindrical core portions 5, 5 are in pressure contact with the inner peripheral surfaces 18, 18 at the tips of the connected pipes 7, 7.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pipe joint.

[0002]

[Prior Art]

 Generally, a screw-in type pipe joint has a taper internal thread portion at an end opening, and an end taper external thread of a pipe to be connected to the female thread portion is screwed.

[0003]

[Problems to be solved by the device]

 In the pipe joint as described above, conventionally, as shown in FIGS. 4 and 5, the in-pipe exposed portions f and g of the female screw portion b of the pipe joint a or the male screw portion e of the pipe d, which are not screwed, are formed in the pipe. There is a problem that the fluid flowing through the pipes easily corrodes and corrodes.

Further, although the core k for preventing the corrosion of the end surface of the pipe d is attached to the end opening of the pipe d, the workability is poor and there is a possibility that the attachment may be leaked.

Further, there is a problem that the core k cannot be adhered to the surface of the coating layer m in the case of thin-walled polyethylene lining by powder coating.

The present invention solves such a conventional problem, and an object of the present invention is to provide a pipe joint that can completely prevent corrosion of the exposed portion in the pipe at the connection portion and can exhibit high sealing performance. ..

[0007]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the pipe joint according to the present invention is such that the inner surface of the inner part of the pipe joint body made of a metal casting having an internal thread at the end is covered with a hard plastic layer. An approximately cylindrical core portion made of soft plastic is continuously projected from the hard plastic layer with an inner peripheral surface of the female thread portion of the pipe joint body and a predetermined gap portion.

[0008]

[Action]

 When the male thread of the pipe to be connected is screwed into the female thread of the pipe joint body, the connected thread is inserted into the specified gap between the inner peripheral surface of the female thread and the substantially cylindrical core made of soft plastic. The end of the ip is inserted. The outer peripheral surface of the substantially cylindrical core portion is pressed against the inner peripheral surface of the pipe to be connected. When the fluid flows in the pipe, the substantially cylindrical core portion is elastically deformed by the pressure in the pipe to expand its diameter, and is pressed more tightly against the inner peripheral surface of the pipe to be connected to exhibit a high sealing property.

[0009]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the drawings illustrating an embodiment.

FIG. 1 shows a case where the pipe joint A is a socket and the connected pipes 7, 7 are connected to both ends thereof. This pipe joint A comprises a pipe joint body 2 made of a metal casting having tapered female screw parts 1 and 1 at its ends, and a hard plastic layer 4 covering the inner surface of the interior of the pipe joint body 2. Left and right soft plastic substantially cylindrical core portions 5, which are continuously projected from the hard plastic layer 4 with the inner peripheral surfaces of the female screw portions 1, 1 of the pipe joint body 2 and predetermined gap portions 3, 3. It consists of 5 and 5.

The hard plastic layer 4 is formed on the inner surface of the inner part of the pipe joint body 2 by injection molding, but preferably the soft plastic substantially cylindrical core portions 5 and 5 are also integrated by injection molding. It At this time, two-color molding is desirable.

The hard plastic layer 4 has a ring-shaped protrusion 6 formed in the center of the inner peripheral surface 13 along the circumferential direction to enhance the fixing force with the substantially cylindrical core portions 5, 5. Further, a plurality of small protrusions 12 having a substantially trapezoidal cross section, a semicircle or a semi-ellipse, etc. are formed on the outer peripheral surface 9 of the substantially cylindrical core portions 5, 5. The small ridges 12 ... May be independent of each other or may be continuous in a spiral shape. In the illustrated example, the tips 16 and 16 of the substantially cylindrical core portions 5 and 5 are located inward of the ends of the pipe joint body 2. Further, the left and right substantially cylindrical core portions 5 and 5 are continuously and integrally formed.

Although not shown, a plurality of longitudinal slits may be provided at equal angular intervals in the circumferential direction from the tips 16, 16 of the substantially cylindrical core portions 5, 5.

In the present invention, the hard plastic has a Rockwell hardness (HR) of (100 to 125) and the soft plastic has a Rockwell hardness (HR) of (40 to 99). It is defined as.

Next, the connected pipes 7 and 7 are corrosion-resistant steel pipes, and are provided with metal pipe main bodies 14 and 14 each having a tapered male screw portion 10 and 10 on the outer peripheral surface of the tip. The body 14 is provided with a plastic anticorrosion layer 15 that covers the entire inner peripheral surface of the body 14.

Therefore, the outer diameters of the small protrusions 12 ... Of the substantially cylindrical core portions 5, 5 are set to be substantially equal to the inner diameters of the connected pipes 7, 7, and the male screw portions 10, 7 of the connected pipes 7, 7 are When 10 is screwed into the female threaded portions 1 and 1 of the pipe joint body 2, the tips of the connected pipes 7 and 7 enter the predetermined gaps 3 and 3 and the anticorrosion layer 15 of the connected pipes 7 and 7 , 15 and the small ridges 12 ... of the substantially cylindrical core portions 5, 5 are fitted in sliding contact with each other.

Further, since the female screw portions 1, 1 of the pipe joint body 2 are tapered, it is easy to insert the tips of the connected pipes 7, 7.

The female screw parts 1, 1 of the pipe joint body 2 and the male screw parts 10, 10 of the connected pipes 7, 7 may be straight without being tapered.

In the connected state, the small ridges 12 ... Of the substantially cylindrical core portions 5, 5 and the inner peripheral surfaces 18, 18 of the connected pipes 7, 7 are in pressure contact.

Furthermore, since the substantially cylindrical core portions 5 and 5 are made of soft plastic, when a fluid such as water flows in the pipe, the substantially cylindrical core portions 5 and 5 are elastically expanded in diameter by the pressure inside the pipe. It deforms and is pressed more strongly by the inner peripheral surfaces 18, 18 of the connected pipes 7, 7 to exhibit high sealing performance. Therefore, it is possible to reliably prevent the fluid from entering the end surfaces 8 and 8 of the connected pipes 7 and the outer peripheral surfaces 11 and 11 of the connected pipes 7 and 7 and to prevent the error in the inner diameter of the male screws 10 and 10 of the connected pipes 7 and 7. Can handle.

Next, FIG. 2 shows a pipe joint A of another embodiment in which the hard plastic layer 4 and the soft plastic substantially cylindrical core portions 5, 5 are fixed by an adhesive agent. Is illustrated.

That is, the hard plastic layer 4 is formed on the inner surface of the inner part of the pipe joint body 2 by injection molding, and the concave groove portion 17 is provided around the end of the inner peripheral surface 13. The soft plastic substantially cylindrical core portions 5 and 5 are formed as separate bodies, and a projecting portion 19 is provided around the base end portion of the outer peripheral surface 9. Then, the protrusion 19 is strongly pressed into the concave groove portion 17 and adhered thereto. Note that welding or fusion may be used instead of adhesion.

Further, FIG. 3 shows a case where the pipe joint A is an elbow, and in this pipe joint A as well, the inner peripheral end portions 20, 20 of the hard plastic layer 4 are substantially cylindrical core portions 5, 5 made of soft plastic. Are fused (adhered at high frequency) or adhered or welded to form a continuous body. Further, in the illustrated example, the tips 16, 16 of the substantially cylindrical core portions 5, 5 are located outward of the ends of the pipe joint body 2.

Further, a case where a large number of round mountain type small protrusions 12 ... Are formed on the outer peripheral surface 9 of the substantially cylindrical core portions 5 and 5 is shown.

It is also preferable that the tips 16, 16 of the substantially cylindrical core portions 5, 5 be located substantially at the same end as the end of the pipe joint body 2. Further, the small ridges 12 ... May have the cross-sectional shape described above.

In addition to the above-described embodiments, the present invention can be freely changed in design without departing from the gist of the present invention, and can be applied to various pipe joints such as cheese and union. If the core part 5 and the hard plastic layer 4 are simultaneously injection-molded in two colors, the core part 5 can be manufactured efficiently. Further, when the core portion 5 is molded separately, there is an advantage that the shapes and pitches of the small ridges 12 and the small grooves can be freely selected.

[0027]

[Effect of the device]

 Since the present invention is configured as described above, it has the following effects.

Since the substantially cylindrical core portions 5 and 5 are made of soft plastic, the substantially cylindrical core portions 5 and 5 are pressed against the inner peripheral surfaces 18 and 18 of the pipes 7 and 7 to be connected to each other, which is high in adhesion. It can exhibit sealing properties.

Therefore, it is possible to cope with the variation in the inner diameter of the connection pipes 7, 7, and the pipe joint body 2 not covered with the resin, the thread forming portion of the connection pipes 7, 7 and the connection pipes 7, 7 It is possible to reliably prevent the in-pipe fluid from entering the exposed portions of the end faces 8 and 8 of the above, and to completely prevent these portions regardless of the screwing depth of the connected pipes 7 and 7.

Furthermore, the plastic anticorrosion layers 15, 15 of the connected pipes 7, 7 can be applied not only to vinyl chloride lining but also to polyethylene lining by powder coating.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part showing another embodiment.

FIG. 3 is a cross-sectional view showing another embodiment.

FIG. 4 is a cross-sectional view showing a conventional example.

FIG. 5 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 Female screw part 2 Pipe joint body 3 Predetermined gap part 4 Hard plastic layer 5 Substantially cylindrical core part

Claims (1)

[Scope of utility model registration request] 1. A hard plastic layer 4 is coated on the inner surface of the inner part of a pipe joint body 2 made of a metal casting having female thread portions 1 and 1 at the ends, and the female body of the pipe joint body 2 is further covered. A pipe characterized in that soft plastic substantially cylindrical core portions 5 and 5 are continuously projected from the hard plastic layer 4 with inner peripheral surfaces of the screw portions 1 and 1 and predetermined gap portions 3 and 3. Fittings.