JPH08312875A - Electrolytic corrosion prevention structure at the end of stainless steel pipe - Google Patents

Abstract

PURPOSE: To prevent electrocorrosion at a connection end by detachably after- installing a sleeve on the connection end of a stainless steel pipe. CONSTITUTION: A different metal box nut 13 is loosely fitted to one end of a stainless steel pipe 10. An expandable insulative sleeve 15 is detachably after- installed on outer peripheral surfaces of a straight pipe 11 and a flare end 12 of the stainless steel pipe 10. Electrocorrosion between the stainless steel pipe 10 and the different metal box rout 13 is prevented through the insulative sleeve 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stainless steel pipe end structure capable of easily and inexpensively preventing electrolytic corrosion at a connecting end of a stainless steel pipe.

[0002]

2. Description of the Related Art In recent years, flexible stainless steel pipes having bellows have been used as water pipes from the viewpoints of prevention of red water generation due to high durability and absorption of displacement due to earthquakes, constant vibration, ground subsidence, etc. Has been adopted as a lot.

In such a water pipe, one end side of a stainless steel pipe is connected from a water supply pipe buried in a public road through a saddle water faucet and joints, and the other end side of the stainless steel pipe is connected with joints. A water stopcock, a water faucet, etc. are connected through the branch pipe to the inside of the residential land.

However, in order to perform such piping work quickly and easily, stainless steel pipes having the following end structure are often used. That is, as shown in FIG. 6, one end side of a stainless steel pipe 1 having a bellows portion 1a is formed as a straight pipe portion 2 having a flared end portion 3, and a cap nut 4 made of a dissimilar metal is loosely attached to the straight pipe portion 2. The cap nut 4 is attached so that it can be fitted freely, and the stopper line 5 inserted into the inner circumferential groove 4a of the cap nut 4 comes into contact with the flange 3a of the flare end 3 to prevent the cap nut 4 from coming off. The female screw 4b formed on the peripheral surface is screwed with a male screw of another member such as a joint so that the pipe connection work at the construction site can be easily performed.

[0005]

By the way, if the cap nut 4 is made of stainless steel, the cost is significantly high. Therefore, a brass cap nut made of a metal different from the stainless steel pipe has been conventionally used. Although used, galvanic corrosion occurs between the brass cap nut 4 and the stainless steel pipe 1 due to the dissimilar metals.

In order to prevent the occurrence of electrolytic corrosion due to different kinds of metals, an insulating seal may be provided between the two, but this type of stainless steel pipe needs to be annealed to correct the deformation of its material structure. Since the cap nut 4 made of a dissimilar metal is attached to the cap nut 4 so that the cap nut 4 can be loosely fitted to the cap nut 4 while preventing the cap nut 4 from coming off, an insulating member that can be attached and removed is required.

The present invention has been made in view of the above circumstances, and can be removably attached to the connecting end of a stainless steel pipe to prevent electrolytic corrosion at the connecting end easily and at low cost. The purpose is to provide a structure for preventing electrolytic corrosion at the end of a stainless steel pipe.

[0008]

In order to achieve the above-mentioned object, the present invention forms a straight pipe portion having one end side of a stainless steel pipe as a flare end portion, and the straight pipe portion is made of a different metal. With the cap nut of the stainless steel pipe end fitted loosely, the stopper line inserted into the inner circumferential groove of the cap nut contacts the flange of the flare end to prevent the cap nut from coming off. The outer peripheral surface of the end portion and the flare end is covered with a deployable insulating sleeve that is detachably attached afterwards to prevent electrolytic corrosion between the stainless steel pipe and the cap nut made of dissimilar metal through this insulating sleeve. It is characterized by

[0009]

According to the present invention, the outer peripheral surfaces of the straight pipe portion and the flare end portion forming the end portion of the stainless steel pipe are retrofitted with the detachable insulating sleeve, so that the insulating sleeve is interposed. As a result, a cap nut made of a dissimilar metal is attached, and electrolytic corrosion between the cap nut and the end of the stainless steel pipe can be prevented easily and at low cost.

[0010]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory sectional view showing a first embodiment according to the present invention.

In the figure, 10 is a flexible stainless steel pipe having a bellows portion 10a. One end side of the stainless steel pipe 10 is formed by a straight pipe portion 11 and a flare end portion 12. 12a is a flange at the flare end 12.

Reference numeral 13 is a brass cap nut that is normally used, and has an internal thread 13a formed on the inner peripheral surface thereof and an inner peripheral groove 13b into which the retaining line 14 is fitted. The inner diameter of the cap nut 13 is the flange 12
Since the cap nut 13 is formed to have a diameter slightly larger than the diameter of a, the cap nut 13 is inserted into the straight pipe portion 11 from the flare end 12 side without being obstructed by the flange 12a, and is loosely fitted in the straight pipe portion 11. Can be installed freely.

When the stopper line 14 is inserted into the inner peripheral groove 13b formed on the inner peripheral surface of the cap nut 13, the inner peripheral groove 1
The retaining line 14 protruding from 3b contacts the flange 12a of the flare end 12 to prevent the cap nut 13 from coming off.

Reference numeral 15 denotes an insulating sleeve. This insulating sleeve 15 has a straight pipe portion 11 as shown in FIGS.
It is formed by a cylindrical portion 15a covering the outer peripheral surface of and a flange 15b provided at one end of the cylindrical portion 15a.
It is formed as a half-split sleeve in which a notch 15c is provided in the longitudinal direction, and it is forcibly deployed from the notch 15c and mounted at the time of insertion.

In this embodiment, the insulating sleeve 15 is made of polypropylene resin and has a temperature of 800K.
Although it is formed to withstand a load of g, any material may be used as long as it has the above-mentioned function.

Further, the flange 1 of the insulating sleeve 15
The outer periphery of 5b is formed to have a diameter slightly larger than that of the flange 12a of the flare end portion 12, so that the flange 12a
The gap formed between the outer peripheral surface of and the inner peripheral surface of the cap nut 13 is sealed.

Further, the flange 15 of the insulating sleeve 15
The short cylindrical portion 15d is formed so as to project from the outer periphery of b, and the flange 1
The short cylindrical portion 15d may be inserted into a gap formed between the outer peripheral surface of 2a and the inner peripheral surface of the cap nut 13.

Further, depending on the load and the like, the material of the insulating sleeve 15, the formation thickness, etc., the shape of the stop line 14 is not limited to a spherical shape, but is, for example, an elliptical spherical shape so that the pressing force is equalized. Good.

According to this embodiment, the insulating sleeve 15 is easily retrofitted by expanding the notched portion 15c while expanding the straight pipe portion 11 of the stainless steel pipe 10 to which the cap nut 13 is loosely fitted in advance. The insulating sleeve 15 covers the outer peripheral surfaces of the straight pipe portion 11 and the flare end portion 12, and the stainless steel pipe 1 is provided through the insulating sleeve 15.
It is possible to prevent electrolytic corrosion between 0 and the cap nut 13 made of a different metal.

Next, a second embodiment shown in FIG. 5 will be described. This embodiment is used as a flexible joint. That is, the flexible stainless steel pipe 20 having the bellows portion 20a has its outer periphery covered by the braided metal blades 21, and both ends thereof are straight pipe portions 2.
2, 23 are formed.

The straight pipe portion 22 side has a flange 24 at its end.
A flare end portion 24 having a is formed, and a stainless sleeve 25 is attached to the outer periphery thereof. An annular groove 25a is formed on the outer periphery of the sleeve 25, and the end of the blade 21 is pressed by the press ring 26 in the annular groove 25a and caulked to prevent the sleeve 25 from coming off from the stainless steel pipe 20. .

27 is a cap nut, and this cap nut 27
Has a female screw 27a formed on the inner peripheral surface thereof, and is screwed and connected to a male screw of another member such as a sluice valve or a saddle diversion valve.
Further, 27b is an inner peripheral groove, and a stop line 28 is inserted into the inner peripheral groove 27b, and the stop line 28 is attached to the flare end portion 24.
By contacting the flange 24a of the
It is designed to prevent

On the other hand, a shimoku 29 is attached to the outer periphery of the straight pipe portion 23, an annular groove 29a is formed on the inner peripheral surface of the shimoku 29, and an annular groove 29b is also formed on the outer peripheral surface. Reference numeral 30 denotes an O-ring, which is pressed by the bulging portion 23a formed in the straight pipe portion 23. Further, 31 is a press ring, and the end portion of the blade 21 has a press ring 31.
Is pressed and crimped to prevent the shimoku 28 from coming off the stainless steel pipe 20. 32 is Shimok 2
Reference numeral 33 is a male screw formed on the outer circumference of 8, and 33 is a rubber cover.

Also in this embodiment, as in the above embodiment,
Electrolytic corrosion between the stainless steel pipe 20 and the cap nut 27 made of a different metal can be prevented, and a good flexible joint can be provided.

[0025]

As described above, according to the present invention, the expandable insulating sleeve can be attached to the connecting end portion of the stainless steel pipe in a detachable and convenient manner. It is possible to easily and inexpensively prevent electrolytic corrosion between the cap nut made of steel.

[Brief description of drawings]

FIG. 1 is an explanatory sectional view showing a first embodiment according to the present invention.

FIG. 2 is an external front view showing a sleeve according to the present invention.

3 is an external side view of the sleeve in FIG.

FIG. 4 is an external front view showing another example of the sleeve according to the present invention.

FIG. 5 is an explanatory sectional view showing a second embodiment according to the present invention.

FIG. 6 is an explanatory sectional view showing an example of a conventional stainless steel pipe end portion.

[Explanation of symbols]

 10 Stainless Steel Pipe 10a Bellows Part 11 Straight Pipe Part 12a Flange 13 Cap Nut 14 Stopping Wire 15 Insulation Sleeve

Claims (1)

[Claims] 1. A straight pipe part having one end side of a stainless steel pipe as a flare end part is formed, and a cap nut made of a dissimilar metal is loosely fitted to the straight pipe part and inserted into an inner peripheral groove of the cap nut. In the structure of the stainless steel pipe end that prevents the cap nut from coming off by the fitted stop line contacting the flange of the flare end, a deployable insulating sleeve is attached to and detached from the outer peripheral surface of the straight pipe part and the flare end. You can freely attach it later and cover it,
A structure for preventing galvanic corrosion of a stainless steel pipe end, which prevents galvanic corrosion between a stainless steel pipe and a cap nut made of a dissimilar metal through the insulating sleeve.