JPS6148696A - Pipe joint - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electrically insulating pipe joint.

[Conventional technology]

In piping systems mainly made of steel pipes, stray current causes corrosion of the pipes. To prevent this, it is effective to use electrically insulating pipe fittings for some of the piping. For this reason, various inventions and ideas have been made regarding this type of pipe fitting, but all of them have a complex structure, have a large number of manufacturing parts, require a lot of time and labor to assemble, and are more difficult to assemble than ordinary pipe fittings. It's big overall. Therefore, extra space is required for piping, and there are restrictions on its use due to the location of the piping.

Furthermore, if a pipe fitting that incorporates a combustible insulating material such as rubber or plastic is simply used for flammable fluid piping such as city gas, in the event of a fire, the insulating material will burn out and the pipe fitting will disintegrate. There was a risk of secondary disasters occurring.

[Problem that the invention seeks to solve]

The object of the present invention is to provide an electrically insulating pipe joint that does not have the above-mentioned drawbacks.

[Means to solve problem fish]

The present invention provides a female threaded joint and a male threaded joint in which an anticorrosive lining layer is applied to the outer circumferential surface, and a sleeve portion extending from the second anticorrosive lining layer is formed outward from one female thread side end. are connected to each other via an electrically insulating coating coated on the surface of at least one of the connecting screws.

〔Example〕

In Fig. 1, 1 is a female threaded joint, and the socket shown in the figure may be an elbow.

The outer circumferential surface of this female threaded joint is coated with a second anticorrosive lining layer 3, and a sleeve portion 4 of the anticorrosive lining layer 3 is formed extending outward at one end. The sleeve portion 4 has an inner diameter that is approximately the same as or slightly larger than the outer diameter of the steel pipe so as to cover the outer periphery of the outer resin-coated steel pipe (not shown, hereinafter referred to as steel pipe) to be connected.

On the female thread side of the other end, there is an anti-corrosion lining layer 31 on the outer peripheral surface.
and a male threaded joint 11 in which a sleeve portion 41 is formed.
are screw-connected via an electrically insulating film 2 coated on either one of the connection screws. Corrosion-proofing lining scraps 31 on the side of the male-threaded joint 11 are sandwiched between the connecting ends of the female-threaded joint 1 and the male-threaded joint 11, and cover the male-threaded terminal end of the male-threaded joint.

The electrically insulating film 2 that covers the connection screw is made of powder of an organic polymer material with excellent electrical insulation such as epoxy resin, polycarbonate, or nylon, which is applied by wet coating such as dipping or spraying, fluidized dipping, or electrostatic coating. or CVD of inorganic materials such as ceramics and glassy substances.
The electrically insulating film 3 is formed by a vapor deposition method such as , sputtering, or ion blasting.

Therefore, the screw-connected female threaded fitting 1 and male threaded fitting 11 are electrically isolated, and the electricity flowing through the piping does not flow to the piping after the joint, preventing corrosion due to electrical causes such as macrocell corrosion. Prevent it from happening.

In addition, the surface of the steel pipe connected to the end of this joint is inscribed in the sleeve portions 4, 4, 1 of the anti-corrosion lining N3.3'l, and a sealant such as butyl rubber is interposed in this inscribed portion, or a rubber seal is inserted. By interposing the pipe, it is completely isolated from the external corrosive environment even if it is installed underground.

Further, a female threaded joint 1 or a male threaded joint 11 is provided on both or one of the anticorrosive lining layers 3 and 31.
A hole 8.81 for insulation resistance measurement is provided to communicate between the pipe and the outside, and after the piping construction is completed, the open insulation between the pipe and the female threaded fitting 1 or the male threaded fitting 11 is completely achieved. It is possible to measure whether

In other words, the hole 8.8 made in this anti-corrosion second-inning layer
Insert the insulation resistance measurement terminal into 1 and measure the insulation resistance. This hole 8.81 is plugged with a blind stopper 6 made of rubber or the like to isolate it from the outside environment except during measurement and inspection. If you want to permanently plug the hole 8.81 after the measurement, use a caulking material such as non-fluid rubber or a fluid sealant instead of the blind plug 6.
You may fill in the

FIG. 2 shows another embodiment of the present invention, in which a female threaded joint 1
The ends of the connecting sides on which the male threaded joint 11 is screwed together are coated with anti-corrosion lining scraps 3.31 on the outer surface of both.
is coated, and a packing 5 is attached to the inner circumferential side thereof. Therefore, when the male threaded joint 11 and the female threaded joint 1 are screwed together via the electrically insulating film 2, the ends of the packing 5 and anticorrosion lining Wi3. There is no penetration of sexual substances.

〔Effect of the invention〕

As explained above, the pipe joint of the present invention allows piping construction to be carried out in the same way as conventional pipe fittings, is completely isolated from the external environment and provides corrosion protection, and is also capable of measuring electrical insulation resistance after piping. It is possible to check whether electrical continuity has been completely interrupted, and reliable piping can be performed1.It also has excellent fire resistance and does not require many complicated parts in terms of manufacturing. It is possible to easily construct piping that is economical and safe over a long period of time, and is extremely useful in industry.

[Brief explanation of the drawing]

tItJ1 is a vertical sectional view of a pipe joint showing one embodiment of the present invention, and FIG. 2 is an R sectional view showing another embodiment. 1: Female threaded joint, 2: Electrical insulating coating, 3.3
1: Anticorrosion lining layer, 4, 41: Sleeve, 8, 8
1: Hole, 6: Blind stopper, 11: Owaji attached joint agent Patent attorney Takashi Honma Figure 1 Figure 2

Claims (2)

[Claims] (1) A female threaded joint and a male threaded joint are provided with an anti-corrosion lining layer on the outer circumferential surface, and a sleeve portion extending from the anti-corrosion lining layer outward from one female thread side end, A pipe joint characterized in that at least one of the connecting screws is fastened to each other through an electrically insulating coating coated on the surface of the connecting screw. (2) In claim 1, at least one of the anticorrosive lining layers applied to the outer peripheral surfaces of the female threaded joint and the male threaded joint is provided with a hole that communicates the outside with the outer peripheral surface of the joint. A pipe fitting characterized in that it can be plugged in.