JPH0343509Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a corrosion-resistant pipe joint for preventing corrosion at the connection end of a metal pipe joint for connecting lined pipes coated with a synthetic resin layer.

Conventionally, anti-corrosion steel pipes with anti-corrosion layers on the inner or outer surfaces have been widely used as a countermeasure against red water in water piping, but the corrosion prevention measures for the ends of the pipes that are inserted into pipe fittings and the inner surfaces of the fittings remain a major problem. has been done. As a countermeasure for this, there are pipe fittings with an anti-corrosion layer applied to the inner surface of the fitting, and pipe end corrosion-preventing sleeves that fit tightly to the end of the pipe, including the inner diameter of the pipe, but both methods provide complete corrosion protection over a long period of time. Things were impossible.

As a conventionally known example, Japanese Patent Application Laid-Open No. 57-83789 has a joint with a threaded part provided with a cylindrical body made of synthetic resin with a thread on the inner surface. When the tube freezes, the synthetic resin cylindrical body deforms or breaks due to the pressure etc. during freezing, which impairs the anti-corrosion function of the pipe end and causes red water, and in cases of severe freezing, the pipe fitting itself may become damaged. There was a problem that led to the destruction of the

In addition, a cylindrical body made of synthetic resin is provided on the inner surface of the pipe joint to prevent fluid from flowing into the gap between the inner surface of the pipe connected between the cylindrical body and the threaded part of the pipe joint and the outer surface of the vip insertion part of the cylindrical body. Some products use a liquid sealant, but due to the aging of the sealant during long-term use, the amount of sealant filled by the operator, or the filling of the sealant by the operator, a gap may develop between the cylindrical body and the inner diameter of the pipe. This can cause internal fluids to enter and corrode the connections.

The object of the present invention is to eliminate the various drawbacks mentioned above and provide a corrosion-resistant pipe joint that can provide a complete anti-corrosion effect and is also excellent in terms of manufacturing and workability.

The gist of the present invention is to attach a cylindrical body made of synthetic resin to the inner surface of a pipe joint, and to provide an extension portion of the cylindrical body having an outer diameter smaller than the inner diameter of the connecting pipe so that the threaded portion of the pipe joint and the cylindrical body extend. In a pipe fitting in which a pipe insertion part for accommodating the pipe end is formed between the pipe fitting and the outlet part, a packing locking part having a predetermined width larger than the inner diameter of the thread is formed in the deep part of the thread of the pipe fitting, and the fitting is connected to the fitting. Between the stop part and the pipe insertion part, an enlarged part that fits into the packing locking part and the cylindrical body extension part for sealing the outer diameter of the cylindrical body extension part and the pipe end surface. This pipe joint is characterized in that it is equipped with a packing consisting of a sleeve seal portion that has an inner diameter that is approximately the same as the outer diameter and an outer diameter that is larger than the inner diameter of the pipe.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a longitudinal cross-sectional view of an example of a socket-type pipe joint, in which a cylindrical body 2 made of synthetic resin is provided on the inner surface of the pipe joint 1, and the cylindrical body 2 has an inner diameter of a pipe 6. Cylindrical body extension part 4 having a smaller outer diameter
A predetermined gap is formed between the threaded part 7 of the pipe joint 1 and the cylindrical body extension part 4 to accommodate the pipe end. Further, on the inner surface of the pipe joint 1, a packing locking portion 8 having an outer diameter larger than the threaded inner diameter of the pipe joint 1 and a predetermined width is formed. The packing 3 has an outer diameter larger than the threaded inner diameter of the pipe joint 1, and has an inner diameter that is approximately the same as the outer diameter of the expanded portion 3' that fits into the packing locking portion 8 and the outer diameter of the cylindrical body extension portion 4. Katsu pipe 6
The sleeve seal portion 3'' has an outer diameter larger than the inner diameter of the sleeve seal portion 3''.

This packing 3 is made of elastic material such as NBR or ethylene propylene rubber, and can be easily deformed by compression or the like. By attaching the enlarged part 3' of the packing 3 to the packing locking part 8 of the pipe fitting 1, the packing 3 will not fall from the pipe fitting 1 before the pipe is connected, and the sleeve seal part 3'' is attached to the fitting 1. The threaded part 7 and the cylindrical body extension part 4
By screwing the pipe 6 into the gap between the pipe 6 and the pipe 6, the cylindrical sleeve seal part 3'' is bent and deformed, and comes into close contact with the outer surface of the cylindrical body extension part 4.
Since the sleeve seal portion 3″ has an inner diameter that is approximately the same as the outer diameter of the cylindrical body extension portion 4 and an outer diameter that is larger than the inner diameter of the pipe 6, the end of the pipe 6 is also elastically connected to the sleeve seal portion. Due to the close contact, fluid does not enter the end of the pipe 6 and corrosion does not occur.

In the above embodiment, by applying a liquid sealant to the threaded portion of the pipe fitting 1 and the threaded portion of the pipe 6, and screwing the pipe, the gap between the sealing member 3 and the threaded portion 7 of the pipe fitting is closed. is filled with the sealant, further increasing the degree of adhesion of the sealant 3 and improving the anticorrosion effect.

FIG. 2 is a cross-sectional view showing another embodiment of the pipe joint, which has a packing 3 like the previous embodiment and also has a recessed part 8 in the deep part of the thread of the pipe fitting 1 to prevent the packing 3 from coming off. If this is done, the same effect can be obtained even if the shape of the pipe joint 1 is as shown in FIG.

As another embodiment, the inner diameter of the sleeve seal portion 3'' of the packing 3 described in the embodiment of FIG. It may also be attached to the cylindrical body extension part 4.
In this case, the packing 3 is in close contact with the outer diameter of the cylindrical body extension 4 and will not fall, so it will not fall even if the enlarged part 3' of the packing 3 and the packing locking part 8 of the pipe fitting 1 are not present. There is no. Further, the pipe joint may be a mechanical joint using a rubber packing, or the outer surface of the pipe joint body may be coated with a synthetic resin.

As described above, the pipe joint of the present invention does not allow internal water to come into contact with the connecting end of the pipe, nor does water flow in. Compared to conventional pipe joints, the pipe joint has better workability and ensures reliable pipe connection without any variation due to construction. This provides a very useful pipe fitting that can prevent end face corrosion.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view showing another embodiment, and FIG. 3 is an enlarged view of the main part of the packing part. DESCRIPTION OF SYMBOLS 1... Pipe joint, 2... Cylindrical body, 3... Seal member, 3'... Seal member ring part, 3''... Sleeve sealing material, 4... Cylindrical body rounded part, 6... Pipe ,
7... Pipe joint threaded part, 8... Pipe joint hollow part.

Claims (1)

[Claims for Utility Model Registration] 1. A cylindrical body made of synthetic resin is attached to the inner surface of a pipe joint, and an extending portion of the cylindrical body having an outer diameter smaller than the inner diameter of the connecting pipe is provided so that the threaded portion of the pipe joint and the pipe are connected to each other. A pipe insertion part for accommodating the pipe end is formed between the pipe fitting and the pipe extension part, and a packing locking part having a predetermined width larger than the inner diameter of the thread is formed at the deep end of the thread of the pipe joint. , between the packing locking part and the pipe insertion part, the enlarged part that fits into the packing locking part and the cylindrical body for sealing the outer diameter of the cylindrical body extension part and the pipe end surface. What is claimed is: 1. A pipe joint comprising a sleeve seal having an inner diameter approximately the same as the outer diameter of the body extension part and a sleeve seal part having an outer diameter larger than the inner diameter of the pipe. 2. A pipe joint as described in claim 1 of the utility model, wherein the outer surface of the metal pipe joint body is coated with a resin.