JPS6347323Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to corrosion prevention of valves installed in pipelines or various devices to control fluid flow.

In normal above-ground piping, the area around the pipe is electrically and chemically isolated from the soil etc. by the air, so compared to underground piping, that is, buried piping, which will be described next. In the case of above-ground piping, sufficient anti-corrosion measures can be taken on the outer surface of the piping system using conventional methods. however,
For example, in cases where there are many underground pipes, such as city gas transport pipes, a railway powered by direct current may be installed near the pipes due to moisture and other ionizing substances contained underground. In such a case, stray currents flowing underground from these flow through conductive substances such as moisture in the ground to city gas pipes buried underground. As a result, an electrical circuit is formed between the direct current railway and the buried gas conduit,
On the outer surface of the buried gas conduit, the flow of current through this circuit causes mass transfer, resulting in so-called electrolytic corrosion. Gas pipes that are in direct contact with the soil are also damaged by natural corrosion such as local battery corrosion and bacterial corrosion in the soil. If corrosion progresses significantly due to these causes of corrosion, a through hole may form in the conduit, causing gas leakage, which may lead to a catastrophic event.

For this reason, conventional methods have been to protect the conduit by wrapping it with anti-corrosion tape, or to form an insulating, corrosion-resistant protective layer such as resin on the outer surface of the pipe, such as with JIS G 3469 polyethylene-coated steel pipes, to ensure that the steel pipe portion of the conduit body is completely connected to the external soil. Moreover, since it is a waterproof membrane, moisture does not pass through it, and it has already been done to prevent the above-mentioned corrosion by completely separating the entire piping system from the external soil with this insulating and corrosion-resistant resin layer.

However, in a buried piping system, the piping equipment includes the above-mentioned pipes, fittings, valves, etc.
Among these, pipes and fittings have a simpler external shape compared to valves, etc., and once the piping work is completed, there are no moving parts during use, and the outer surface is protected against corrosion. Formation of resin films, etc.
Attaching anti-corrosion tape etc. is relatively easy. Therefore, in the case of ordinary underground city gas pipelines, as shown in Figure 1, an underground pit P is installed, and the valve V is piped into this pit, so that the valve body does not come into direct contact with the soil, as with above-ground piping. In this way, countermeasures are taken using the above-mentioned anti-corrosion method. The valve V is operated by opening the lid 17 shown in FIG. 1 and connecting the operating handle to the valve stem 5.

However, this method is not suitable for large cities.
The rising cost of acquiring land for the Pituto facility;
Because it is physically difficult to construct pit facilities due to overcrowding of underground structures, etc., it has become necessary to find a method that avoids the use of pits as much as possible, especially for valve facilities in buried piping.

Therefore, as shown in Figure 2, after connecting the valve V to the pipe, the surrounding soil does not interfere with the valve rotation operation part, that is, the valve stem shaft for valve rotation in the gland part. A method is used in which a soil interference protection cylinder 23 is provided from the ground surface, and a small pit 16 having a lid 17 for inserting an operating handle is provided near the ground surface. Compared to the method of housing the entire valve V in the pit 16 shown in FIG. 1, this method reduces costs because the pit is smaller, and also significantly improves space problems even in urban areas. However, if the external force from the earth's surface is directly transmitted to the valve V, the valve V
Of course, the plumbing pipes 21, 21'
This is dangerous as it may lead to fatigue failure of the connection parts, etc. Therefore, in the method shown in FIG. 2, it is necessary to mechanically shut off the pit 16, the protection tube 23, and the valve V so that the vibrations and loads of automobiles running on the ground are not directly transmitted to the piping. Therefore, in FIG. 2, the connecting portion between the pit 16 and the protective tube 23 and the connecting portion between the protective tube 23 and the valve V are usually joined using clay or the like. Therefore, this clay connection does not have a perfect waterproof sealing function. As a result, this second
In the method shown in the figure, the valve body will come into direct contact with the surrounding soil, moisture etc. will enter the rotating operation shaft, and the valve V will be subject to electrical and chemical corrosion. Therefore, when carrying out the method shown in FIG. 2, it is necessary to take sufficient anti-corrosion measures for the valve V. For this reason, the valve body is usually wrapped with anti-corrosion tape or coated with anti-corrosion paint after the valve piping is completed. However, it is difficult to take anti-corrosion measures at the joint between the rotating part of the valve rotating operation part and the main body, since one part rotates and the other part is fixed. It is particularly difficult to prevent electrolytic corrosion caused by the infiltration of moisture. Furthermore, the above-mentioned work of wrapping the anti-corrosion tape is done at the piping site, and compared to inside a factory, it is very difficult to clean the outside surface of the piping and completely remove moisture and foreign matter. As a result, sufficient anti-corrosion treatment cannot be carried out, and local corrosion progresses due to electrolytic corrosion, etc., and eventually through holes are formed, which may cause accidents such as gas blowouts. Gas leakage due to corrosion has actually occurred.

The purpose of the present invention is to prevent the above-mentioned dangers.

Therefore, the present invention provides a valve for underground burial as described above, in which an insulating resin is bonded between the rotational connection external boss member and the rotational connection internal boss member in the valve rotation operation part, and the first insulation An integrated rotating cap made of layers, and a second continuous layer made of insulating resin on the outer surface of the valve body.
a valve covering insulating layer, and an insulating elastic seal member is interposed at the joint between the first insulating layer and the second insulating layer to rotatably connect the rotary cap and the valve body. At the same time, a continuous insulating layer is formed over the entire surface of the bulb.

The present invention will be explained below with reference to embodiments shown in the drawings.

Fig. 3 shows an embodiment of the present invention. In Fig. 3, the valve is a ball valve, and the conduits 21, 21' and the valve bodies 1, 2 are connected by flanges with bolts and nuts 18, 19. has been done. Here, an insulating resin material 11, for example, hard vinyl chloride, is used in the gap formed by the rotational connection external boss 12 (hereinafter referred to as outer cap) and the rotational connection internal boss 10 (hereinafter referred to as inner cap) of the valve rotation operation section. The structure is such that the two caps are joined together so that they do not come into contact with each other, and the rotational force for rotating the valve applied to the outer cap 12 can be sufficiently transmitted to the inner cap 10 via the insulating resin material 11. The above is a rotating cap having an insulating layer. A packing retainer 9 is connected to the valve body 1 by bolts 13 within this rotating cap. A continuous valve covering insulating layer 22 is formed on the outer surface from the valve bodies 1 and 2 to the conduit 21. At this time, the insulating layer covers all the bolts, nuts 8, 18, 19, etc., and it goes without saying that the valve body must not be in contact with the outside. The joint between the insulating layer 22 of the valve body and the rotating cap is made of an insulating resin material that has insulation and sealing properties between the packing holder 9 and the outside inside the rotating cap, and is formed into a slidable shape. 15 is bonded or integrally formed with the valve body insulating layer 22. In this embodiment, an O-ring 25 was used as the sealing material, but any material may be used as long as it has both insulation and sealing properties.
To operate such a ball valve, the operating handle is fitted into the external rotating boss 12 and rotated to transmit rotational force to the valve stem. At this time, the rotating cap and the valve body are insulated. It is covered with a layer, and the joint between the two has insulation and sealing properties,
Since it is slidable, it can be rotated freely.

Fig. 4 shows another embodiment of the present invention, which is the same as the previous embodiment in that an insulating layer is formed on the pivot cap and the valve body, but the difference is that the joint between the two is joined with a bellows-shaped insulating material 15 and fixed with bands 26, 27, and the conduit connection is a welded ball valve. In this embodiment, the flexible movement of the bellows-shaped insulating material allows the rotation of the valve stem while providing insulation and sealing properties.

The valve of the present invention constructed as described above has the function of preventing electrical corrosion as well as the original function of the valve.

Therefore, according to this invention, 1) there is no need to install expensive pits, 2) there is no need to apply complicated anticorrosive tape or anticorrosive paint, and 3) the joints can rotate freely when the valve is operated while still having a waterproof seal. As a result, it is possible to obtain a cheap, reliable, and safe anticorrosive valve.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional embodiment, Fig. 2 is a sectional view showing another conventional embodiment, Fig. 3 is a longitudinal sectional view of a valve showing an embodiment of the present invention, and Fig. 4 is a sectional view showing a conventional embodiment. FIG. 7 is a vertical sectional view of a valve showing another embodiment of the present invention. 1, 2...Valve body, 3...Ball, 4,
4'... Seat ring, 5... Valve stem, 6... Gasket, 7, 20, 21'... Gasket, 9...
Packing presser, 14...stopper, 21,2
1'... Conduit, 16... Pit, 10... Rotating connection internal boss, 11... First insulating layer, 12...
Rotation connecting external boss, 15... Insulating member, 22...
...Second insulating layer, 23...Protective tube, 25...O ring, 26, 27...Band.

Claims (1)

[Scope of utility model registration request] A rotatable valve body is provided in the valve body, a ring-shaped seat ring is interposed between the outer peripheral surface of the valve body and the inner surface of the valve body, and the valve body is rotated about a rotation shaft outside the valve body, In an underground valve for controlling fluid, an insulating resin is bonded between a rotational connection boss member in a valve rotation operation part and a rotational connection internal boss member to form a first insulating layer. A second insulating layer is formed as a continuous layer of insulating resin on the entire outer surface of the valve body, and an insulating layer is formed at the joint between the first insulating layer and the second insulating layer. A corrosion-preventing valve characterized in that the rotating cap and the valve body are sealed and rotatably joined with an elastic sealing member interposed therebetween, and a continuous insulating layer is formed over the entire surface.