JPS5923321Y2 - Short cylindrical pipe structure in gas switch - Google Patents

Description

[Detailed description of the invention] The present invention is to form an insulating protrusion made of a material other than alumina on the outer circumferential surface of a short cylindrical insulator tube made of alumina porcelain and to prevent creeping discharge between the live part of the insulator tube and the ground. This invention relates to the structure of a short cylindrical hard tube whose extension is prevented by the insulating protrusion.

SF6 gas (sulfur hexafluoride gas), which has excellent insulation and arc-extinguishing properties, is sealed and enclosed in the case, and this SF6 gas is sprayed onto the arc generated between the electrodes when the load switch is turned on to extinguish the arc. Switches designed to do this are well known.

By the way, in this type of switch filled with SF6 gas, the sunrise wire portion is often of a metallized structure in order to maintain airtightness.

As shown in Figure 1, this is done by sealing the space between the short cylindrical insulator tube 2 made of alumina porcelain and the case 1 made of metal such as stainless steel, and between the insulator tube 2 and the center conductor 8 using a metal sealing member such as Kovar. However, in the above structure, when abnormal voltage such as lightning enters, the ring-shaped metal body 13 connected to the central conductor 8, which is a live part, and the case 1 on the ground side will be damaged. A creeping discharge occurred using the outer circumferential surface 2a of the short cylindrical insulator tube 2 as a discharge path, leading to a flashover accident. The creeping streamer extends toward the ground side on the outer circumferential surface 2a of the short cylindrical insulator tube 2, and flashing occurs between the two relatively easily.

Therefore, an insulating protrusion is integrally formed on the outer circumferential surface 2a of the short cylindrical insulator to prevent the extension of this creeping discharge and increase the withstand voltage performance (flash voltage) of the same part. There were several problems in forming the protrusions.

In other words, the above-mentioned short cylindrical insulator pipe must be airtightly maintained by metal sealing, must not become brittle due to decomposition products of SF6 gas, must have mechanical strength, and must have durability. For these reasons, alumina porcelain is used. However, if an insulating protrusion is to be integrally formed on the outer circumferential surface 2a of this short cylindrical insulator tube 2, a cylindrical short piece with an outer diameter of 11 as shown in FIG. After forming the cylindrical porcelain tube 2 using a rubber press, the portion 2' indicated by the chain double-dashed line in the figure is completely shaved off, leaving the protruding portion 14'. In addition to wasting the material, the presence of protrusions made it difficult to polish the outer surface, which is essential when metallizing.

This project is proposed in view of the above points, and solves the above problems by integrally bonding and forming insulating protrusions made of an insulating material other than alumina on the outer peripheral surface of a short cylindrical insulator tube made of alumina porcelain. A short cylindrical insulator tube made of alumina porcelain is airtightly attached to a metal case filled with SF6 gas, and the outer circumferential surface of the insulator tube is connected between the live part of the insulator tube and the ground. In the insulating tube, an annular insulating protrusion is integrally formed to prevent the extension of creeping discharge on the outer peripheral surface of the insulating tube, and the insulating protrusion contains 100 parts by weight of urethane-modified epoxy resin (base resin). The present invention relates to a short cylindrical insulator structure for a gas switch, characterized in that an insulating member containing a curing agent in a blending ratio of 20 parts by weight is integrally bonded to the insulating member.

An embodiment of the present invention will be described below with reference to FIG.

Reference numeral 1 denotes a case made of stainless steel, to which a short cylindrical insulator tube 2 made of alumina porcelain is attached through a metal piece 3 with a sealing part.

The metal piece 3 is welded to the case 1, and the short cylindrical insulator tube 2 is metallized and then fixed by brazing. Polished.

Reference numeral 4 denotes an external insulator tube made of ordinary porcelain. After the narrow diameter portion 4a is inserted into the short cylindrical insulator tube 2a with a certain insulating space A, a packing 5 is interposed between the flange portion of the insulator tube and the case, and then tightened. It is tightened and fixed to the case 1 with a nut 6 and a presser fitting 7.

Reference numeral 8 denotes a center conductor inserted into the short cylindrical insulator tube 2, and its one end is attached to a fixing metal fitting 16 which is preliminarily bonded to the tip 4b of the outer insulator tube 4 with cement 9 and adhesive 10, and a nut 11 and positioning. It is tightened and fixed by an adjustment nut 12, and the other end located inside the case 1 is supported by the short cylindrical insulator tube 2 via an annular metal body 13.

Note that this annular metal body 13 is made of Huval material, which is a sealing member, and is used to seal between the short cylindrical insulator tube 2 and the center conductor 8. The short cylindrical insulator tube is soldered after being metallized, and is soldered to the center conductor. They are directly brazed.

A indicates the brazed part. 14 is the outer peripheral surface 2a of the short cylindrical insulator tube 2
The annular metal body 13 connected to the center conductor 8, which is the live part of the insulating tube, and the case 1 on the ground side or the metal piece 3 connected to the case are interposed and integrally bonded. This is an annular insulating protrusion, and the protrusion is an insulating member (with a compounding ratio of 20 parts by weight of the curing agent when the urethane-modified epoxy resin (main resin) is 100 parts by weight).
It is made of Araldite Clean Cast HF), which has a dielectric constant ε close to that of alumina porcelain, has high electrical insulation properties, and has a high degree of flexibility even after hardening, so it can be used for short periods of time. Even if the cylindrical porcelain tube thermally expands or contracts, this is buffered and no stress is applied to the cylindrical porcelain tube.

In addition, in order to form the above-mentioned insulating protrusion 14 on the outer circumferential surface 2a of the short cylindrical insulator tube 2, a mold is attached to the short cylindrical insulator tube 2, and then the above insulating material is injected into the mold, and after hardening, the same mold is removed. form.

15 is an insulator made of the same insulating material as the insulating projection 14;
Reference numeral 6 denotes a rubber-based contraction tube that insulates and insulates the air-side outer peripheral surface of the center conductor 8.

The present invention has the above-mentioned configuration, and even if an abnormal voltage such as that caused by intruding lightning is applied between the live part of the short cylindrical insulator tube and the earth, and a flash attempt is made on the outer circumferential surface of the short cylindrical insulator tube, As mentioned above, because the annular insulating protrusion is integrally bonded,
As a result of the projection preventing the creeping streamer (surface discharge) from expanding, the creeping flashover voltage of the short cylindrical insulator tube can be increased even if the short cylindrical insulator tube has a relatively short shape.

In addition, when forming the insulating protrusions, they are formed integrally with the outer circumferential surface of the short cylindrical insulator pipe after molding.
As the insulating material is bonded and formed with an insulating material that has a dielectric constant ε close to that of alumina porcelain, has high electrical insulation properties, and is highly flexible even after curing, it is easy to process short cylindrical porcelain tubes. In addition, it can be manufactured economically without wasting materials, and it has excellent electrical properties such as no difference in electrical insulation and creeping discharge blocking effect compared to when it is formed integrally with alumina porcelain. In addition, even if the short cylindrical insulator tube expands or contracts due to temperature, it can be buffered (absorbed) by the highly flexible (elastic) insulating projections, and unnecessary It has the advantage of being able to stably maintain the airtightness of the insulator without applying stress, and is extremely effective in practice.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the main parts of a gas switch showing an embodiment of the present invention, and FIG. 2 is a sectional view of a short cylindrical insulator pipe for explaining a conventional processing method. 1...Case, 2...Short cylindrical pipe, 2a
...Outer peripheral surface, 3...Metal piece, 13...
...Annular metal body, 14...Curved insulating protrusion.

Claims (1)

[Scope of utility model registration request] A short cylindrical insulator tube made of alumina porcelain is airtightly attached to a metal case filled with SF6 gas, and on the outer circumferential surface of the attached insulator tube is an annular insulating protrusion interposed between the live part of the insulator tube and the ground. is integrally formed to prevent the extension of creeping discharge on the outer circumferential surface of the insulating tube, and when the insulating protrusion is 100 parts by weight of urethane-modified epoxy resin (base resin), the curing agent is 20 parts by weight. A short cylindrical insulator structure for a gas switch, characterized in that it is integrally bonded with an insulating member having a mixing ratio of 1.