JP2011220431A - Corrosion proof pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corrosion proof pipe joint that is superior in sealing and workability for piping connection.SOLUTION: The corrosion proof pipe joint includes a metallic pipe joint body having a female screw section in its end, wherein the inside other than the female screw is covered with a protective layer made of resin. A nearly cylindrical core is extended inside the female screw and integrally or separately from the protective layer, and an engaging recess is provided between the core and female screw to connect a pipe, and furthermore a sealing agent with lubricity is applied beforehand to the female screw.

Description

  The present invention relates to an anticorrosion pipe joint in which a protective layer of a synthetic resin is provided on a screw-in type metal pipe joint, and particularly relates to a precoat anticorrosion pipe joint in which a sealing agent is previously applied to a female thread portion.

The occurrence of corrosion becomes a problem when metal fittings are used for pipes for water supply, water supply and hot water supply.
Therefore, an anticorrosion pipe joint in which a resin protective layer is provided at least inside the pipe joint is used.
In addition, in pipes using this type of anticorrosion pipe joint, the external thread formed on the end of the inner peripheral lining steel pipe was manufactured by cutting. Recently, however, a rolling roller (rolling die) or the like has been used for the steel pipe. There are an increasing number of formed rolling screws that are pressed against the outer periphery of the metal and plastically processed.
The rolling screw is a method of plastic deformation by applying a pressure exceeding the yield point to the material, so unlike the cutting process that cuts the fibrous metal structure, the so-called fiber flow remains, also accompanied by work hardening, Excellent mechanical properties such as strong strength can be obtained.
However, on the other hand, when the steel pipe and the pipe joint are screwed and connected, there is a problem that the tightening torque is larger than that of the cutting screw.

Patent Document 1 discloses an anticorrosion pipe joint in which a sealing agent is applied to a female thread portion.
However, the sealing agent disclosed in the publication reacts at room temperature after coating, and has adhesiveness and rubber properties. Specifically, the sealing agent has a viscosity of silicone, urethane, polysulfide, butyl, epoxy acrylic resin, etc. It is described as having elasticity.
Therefore, the tightening torque between the steel pipe and the pipe joint is further increased.

JP-A-60-231090

  An object of the present invention is to provide a corrosion-resistant pipe joint having high sealing performance and excellent workability in pipe connection.

The anticorrosion pipe joint according to the present invention is a anticorrosion pipe joint in which a metal joint body having a female threaded portion at an end and the inside other than the female threaded portion is covered with a resin protective layer, and is substantially cylindrical. A threaded recess for connecting a tube between the core and the female screw part, and extending from the protective layer integrally or separately to the inner side of the female screw part. A sealant having lubricity is previously applied to the part.
The sealing agent is not particularly limited as long as it has lubricity, but a fluorine-based sealing agent based on a fluorine-based polymer is preferable.

  In the anticorrosion pipe joint according to the present invention, since a sealing agent having lubricity is pre-coated on the female thread part of the joint body, a steel pipe having a rolled male thread part can be connected as it is, and the sealing agent Since this has a lubricating effect, the tightening torque is smaller than that of a conventional cutting screw, and connection work is facilitated.

The structural example of the anticorrosion pipe joint which concerns on this invention is shown. An example in which a pipe joint and a pipe are screwed together is shown.

An example of the structure of a pipe joint according to the present invention is shown in FIG.
A metal joint body 11 made of cast iron or the like has a female threaded portion 15 at the end, and a substantially cylindrical resin core 12 is disposed inside the female threaded portion 15 so as to form a predetermined gap. It is.
In addition, although FIG. 1 showed the elbow type, the pipe joint which concerns on this invention is not limited to this elbow type, It is applied to various pipe joints, such as a socket and cheese.
The female thread portion of the joint body 11 is a rolled screw, and the protective layer 13 made of resin is provided inside other than the female thread portion.
The protective layer 13 may be a resin lining or a powder coat.
The embodiment shown in FIG. 1 is an example in which the core 12 is formed as a separate body and bonded and bonded at the protective layer 13 and the joint portion 14. However, the core 12 and the protective layer 13 are integrally formed by injection molding or the like. May be molded.
Moreover, it is an example in which a ridge 12c along the fluid flow direction is formed on the inner periphery of the core 12.

The female thread portion 15 is coated and coated in advance with a cross-linking sealant based on a fluoropolymer.
Thereby, the rust prevention of the female thread portion is high, and there is no fear of corrosion even when stored for a long time.

FIG. 2 shows an example in which a pipe 1 made of a resin-lined steel pipe is connected to the pipe joint according to the present invention.
The inner peripheral surface of the steel pipe is an example in which a resin-made inner peripheral covering portion 1a is formed by lining, and an outer peripheral covering portion 1b is also formed on the outer peripheral portion.
In this embodiment, a fin portion 12a is formed on the entire outer periphery of the core 12 so as to absorb the inner peripheral variation of the tube 1, and when the tube 1 is screwed into the screwing recess 17, the fin portion 12a becomes the convex portion 12b. The core 12 and the tube 1 are sealed so as to come into contact with each other.
Since the fluorine-based sealant is previously applied to the female thread portion 15, the lubrication effect reduces the screwing torque and facilitates the connection work.

DESCRIPTION OF SYMBOLS 1 Pipe 1a Inner periphery coating | coated part 1b Outer periphery coating | coated part 1c Male thread part 11 Joint main body 12 Core 12a Fin part 12b Projection part 12c Projection part 13 Protective layer 14 Joining part 15 Female thread part 16 Sealing agent 17 Screwing recessed part

Claims (2)

A metal fitting body having a female threaded portion at the end and an anticorrosive pipe joint in which the inside other than the female threaded portion is covered with a resin protective layer,
A substantially cylindrical core is provided on the inner side of the female screw part and extending integrally or separately from the protective layer, and a threaded recess for connecting a tube between the core and the female screw part is provided, An anticorrosion pipe joint, wherein a sealing agent having lubricity is previously applied to the female thread portion.   The anticorrosion pipe joint according to claim 1, wherein the sealant is a fluorine-based sealant.

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