JPH0557590U - Composite pipe fitting - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent water leakage, deformation, and separation of composite pipe joints, one of which is a plastic joint and the other of which is a metal joint. [Constitution] The tip of the plastic joint body 1 is attached to the square groove 1
It is formed by the ridges 12 following 1. A metal cap nut 4 is fitted with a metal plate support fitting 3 that covers the outer surfaces of the ridges and square grooves sandwiched therebetween. The outer surface of the tubular body 2 is pressed against the outer surface of the ridge with a rubber packing 5 interposed therebetween. The outer peripheral surface of the tubular body is tightly fastened with screws 21 and 41 on the inner peripheral surface of the cap nut. [Function] When the cap nut and the pipe are tightened with the screw, the rubber packing prevents water leakage of the pipe. External force of tension is received by the ridges and support fittings, and external force of torsion is endured by the strong coupling between the cap nut and the pipe body.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a composite pipe joint in which one is joined with a plastic pipe and the other is joined with a valve, a metal pipe, and a metal pipe body joined with other metal members.

[0002]

[Prior Art]

 Since plastic pipes are lightweight and have high corrosion resistance, they have come to be used in many applications in place of metal pipes. In this case, it is advantageous with him to use plastic pipe joints as well, and a unique joining method for plastics such as the electrofusion method has been developed. For example, there are many advantages over joining steel pipes and iron joints.

By the way, it is necessary to connect one end with a plastic pipe at the end of a pipe line, but the other end with a metal member such as a valve or a metal pipe. A composite pipe joint must be provided by integrally connecting the joint body and the metal pipe body. For this, a pipe (insert metal fitting) was previously inserted into a mold for plastic injection molding when manufacturing a pipe joint, and a combination of an upper mold, a lower mold and a core mold was used. Often, a plastic melt is injected into the gap to form a plastic joint body that is joined to the tube. In this pipe joint, as in other cases, no water leakage should occur at the joint. However, because it consists of a combination of different members, the plastic joint body and the metal pipe body, special consideration must be given to water leakage as compared to the case of using a single material.

FIG. 3 is an example of a conventional technique, in which one joint of a plastic joint body 1a forms a joint with a plastic pipe in which a heating wire 13a is embedded, and the other joint is made of a metal pipe. A joint portion is formed by (insert metal fitting) 2a, and a pipe screw 22a is engraved to be screwed with a screw of a mating member. Further, in order to prevent the pressure water passing through the inside of the tubular body (insert metal fitting) 2a from leaking to the outside, the projecting ridge 101 which is complicatedly bent is provided in the outer peripheral shape to be inserted. In other words, this is an example designed with the idea that even if water leakage occurs, it must be leached in a complicated and long distance before it reaches the outer surface, so that water leakage can be stopped on the way.

FIG. 4 illustrates a conventional technique disclosed in Japanese Patent Laid-Open No. 253089/1990, in which one side of a pipe joint is a crosslinked polyolefin layer 1b, and a plastic pipe 102 as a connection target and a so-called electro It is welded by the fusion method. The other is a metallic tube 2b, the outer end of which is engraved with a male screw 24b for attaching a metal tube or valve, and the other end is projected and inserted into the crosslinked polyolefin layer, and the modified polyolefin layer 103 is formed in the middle of the two. Has been done. The gist of the present invention is that a non-crosslinked polyolefin layer 104 is interposed in order to apply the electrofusion method to a crosslinked polyolefin layer that is excellent in high-temperature characteristics but cannot be fused to a plastic pipe, and that it is difficult to bond with a metal pipe body. The modified polyolefin layer 103 is interposed in the polyolefin layer, which increases the mutual adhesive force to maintain the function of the pipe joint.

[0006]

[Problems to be solved by the device]

 As shown in Fig. 3, the method of complicating the shape of the pipe (insert metal fitting) to prevent the progress of water leakage is that the size of the pipe itself increases and the weight also increases. There is a risk that the balance in strength and center of gravity will be significantly lost, and in order to prevent this, the size and weight of the entire pipe joint must be increased. Further, for example, in the case of a polyolefin resin, the adhesiveness with a metal is poor, so no matter how complicated the outer peripheral surface to be inserted is, it is impossible to expect a water sealing effect. In addition, if a complicated ridge is provided on the outer peripheral surface that is inserted when manufacturing a pipe joint, the injection of molten plastic that has collided impinges on the flow and reduces the flow force, creating a complete gap between the ridges. The problem remains that it cannot be filled tightly. The same can be said for the prior art of FIG. 4, and it can be evaluated that the non-crosslinked polyolefin layer, which facilitates electrofusion, is sought to be integrated, but it promotes the adhesive action with a completely different metal pipe body. Therefore, even if the modified polyolefin layer is applied, it is still not sufficient to solve the problem. As long as it is a pipe joint, it cannot be considered that there are no cases where external forces such as tension or twist act on the pipe. It is a normal course that vibrations and deformations are applied to the building and the ground where the pipeline is installed, and it is necessary to fully predict that the stable condition at the beginning of piping will collapse due to these external forces.

In order to solve the above-mentioned problems, the present invention is such that in a composite pipe joint in which different materials such as metal and plastic are combined, the pipe may come off or water may leak even if an external force such as pulling or twisting is applied. It aims to provide a structure that prevents troubles and maintains a strong splicing relationship.

[0008]

[Means for Solving the Problems]

 In the composite pipe joint according to the present invention, the plastic joint body 1 has a tip formed by an annular projection 12 following the square groove 11, and a metal for continuously covering the square groove 11 and the outer peripheral surface of the projection 12. The outer periphery of the tubular body 2 in which one end of a metal cap nut 4 is rotatably fitted to the stepped portion with the plate support metal fitting 3 sandwiched therebetween, and press-contacted with the outer surface of the ridge 12 and the rubber packing 5 separated. The above problem is solved by the fact that the surface is screwed tightly with the cap nut 4.

[0009]

[Action]

 Unlike the prior art, the present invention does not embed a metal tube (insert metal fitting) inside a plastic joint body to integrate them. Since the joint body 1 and the pipe body 2 are adjacent to each other with the rubber packing 5 sandwiched therebetween, and they are pressed against each other by tightening the cap nut 4, there is no risk of water leakage from the pipe line to the outer peripheral surface, and the pipe line may be slightly Even if bending occurs at the joint part due to external force, it is dealt with by elastic deformation of the rubber packing and prevents water leakage.

When an external tensile force acts on this joint, the load concentrates on the inner surface of the cap nut that fits into the ridge and the step at the end of the joint body. The support metal fitting 3 intervenes to receive the load, and strongly supports the ridge so that it is not deformed, broken, or pulled out.

When the outer peripheral surface of the tubular body 2 and the inner peripheral surface of the cap nut are screwed together, for example, by applying an adhesive and screwing them together, it is possible to make them adhere tightly after fastening the screws. Even if external force of torsion is applied to the joint, it will not loosen easily. Even if a strong external force of torsion is applied, it exceeds the frictional force between the outer peripheral surface of the ridge and the support fitting, and between the support fitting and the inner peripheral surface of the cap nut, and the joint body and pipe body rotate relative to each other. It does not cause troubles such as water leakage and leaks.

[0012]

【Example】

 FIG. 1 shows an embodiment of the present invention, in which one side of a plastic joint body 1 opens a joint 14 with a plastic tube in which a heating wire 13 is embedded, and the other side is a ridge 12 continuing from a square groove 11. A step is formed. The material of the plastic joint body can be applied to all synthetic resins such as polyethylene, polybutene, polyvinyl chloride, etc. However, if water is used for the water, polyethylene, which is also denser than pipes, can be applied to the joint body. Good results are obtained. The joint between the pipe and the joint body 1 is shown by the electrofusion method in this example, but it goes without saying that other methods such as adhesion and mechanical method can be applied. The support fitting 3 is formed of a ring-shaped body formed by bending a thin steel plate twice at right angles, and covers three surfaces connecting the outer surface of the square groove 11 and the inner and outer surfaces of the ridge 12. The cap nut 4 is rotatably fitted in the square groove 11 with the support fitting 3 interposed therebetween. In practice, the heating wire 13, the support metal fitting 3, and the cap nut 4 are fitted into the plastic injection mold at predetermined positions to assemble, and liquid plastic is injected into the mold space to integrate the three parts. It is rational to mold it.

A female screw 41 is engraved on the inner peripheral surface of the cap nut 4, and is connected to the engraved pipe body 2 with a male screw 21 that is screwed with this female screw. At this time, a liquid adhesive is applied to the threads of one or both of the screws in advance, and if both screws are screwed together via the rubber packing 5, the rubber packing sandwiched will be pressed as the screw progresses. To completely fulfill the water sealing function. Further, the threaded portion does not loosen even if a considerable external twisting force is applied by the action of the adhesive. In order to prevent the loosening by tightly screwing the pipe body and the cap nut, it is conceivable to use a knock pin or a set screw in addition to using an adhesive. A female screw 22 is engraved on the other side of the pipe body 2 to open a joint portion 23 for mounting a metal pipe body, a water meter, and the like.

FIG. 2 shows another embodiment of the present invention in which a male screw 24 for mounting is engraved on the outer peripheral surface at the end of the tube body 2.

[0015]

[Effect of the device]

 In the composite pipe joint according to the present invention, the metal insert fitting and the plastic joint body are not directly engaged as in the conventional case, but are indirectly engaged via a cap nut. There is no need to rely on direct engagement for water leakage or deformation and retention due to external force, the rubber packing sandwiched between the two completely prevents water leakage, and external forces such as tension and twist are supported by support metal fittings and cap nuts. It absorbs due to the adhesiveness and elastic deformation of rubber, greatly reducing the risk of peeling and fragmentation. The pipe body can be used in any shape and condition as long as the male thread on the outer peripheral surface can be screwed onto the inner peripheral surface of the cap nut, thus ensuring versatility and highly workable piping work.

[Brief description of drawings]

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

FIG. 2 is a vertical sectional front view showing another embodiment.

FIG. 3 is a vertical sectional front view showing a following technique.

FIG. 4 is a vertical sectional front view showing another conventional technique.

[Explanation of symbols]

 1 Joint body 2 Tubular body 3 Support bracket 4 Cap nut 5 Rubber packing 11 Square groove 12 Projection

Claims (1)

[Scope of utility model registration request] 1. A joint body 1, one of which is a joint with a plastic pipe, and the other of which is a metal pipe body 2 in which a pipe screw is engraved.
In a composite pipe joint formed by combining the above, a metal which forms the front end of the plastic joint body 1 with an annular protrusion 12 following the square groove 11 and continuously coats the outer peripheral surfaces of the square groove 11 and the protrusion 12. One end of a metal cap nut 4 is rotatably fitted to the stepped portion while sandwiching a plate support metal fitting 3, and the protrusion 1
2. A composite pipe joint characterized in that the outer peripheral surface of the tubular body 2 which is pressed against the outer side surface of the rubber sheet 2 and the rubber packing 5 is screwed and tightly fitted to the cap nut 4.