JPS63166111A - Explosionproof porcelain tube for gas- filled insulation equipment - 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 is used for gas-filled insulating equipment such as gas bushings, current transformers, and lightning arresters that are filled with insulating gas. This invention relates to an explosion-proof insulator for gas-filled insulating equipment that can minimize the scattering of fragments even if the insulating equipment explodes.

(Prior technology) Gas bushings, gas bus cable heads, current transformers,
An insulating gas such as SF, gas, or N8 gas is sealed inside the lightning arrester, so if the insulator pipe cracks due to some external force, the internal pressure will accelerate the destruction and the fragments will break out. There is a risk of an explosion resulting in scattering to the surrounding area. The scattering of such fragments may injure workers and may also destroy the insulating pipes of surrounding electrical equipment, causing secondary disasters.
As shown in Publication No. 9, there is a known structure in which an explosion-proof inner cylinder made of reinforced plastic is attached with a gap for filling an insulating gas inside the insulator to absorb the energy of an explosion. There is.

However, unlike metal parts, porcelain insulator tubes require large dimensional tolerances, so in order to insert the explosion-proof inner cylinder with a slight corner on the inner surface, it is necessary to match the actual product or to make multiple This has the disadvantage that manufacturing costs are extremely high because it is necessary to stock up on items and combine items with matching dimensions. In addition, in lightning arresters, circuit breakers, etc., semiconductor elements and switching devices are incorporated inside the insulator tube, so the above structure also has the disadvantage that the diameter of the insulator tube must be significantly increased.

In order to solve these conventional drawbacks, a structure in which an explosion-proof coating is bonded to the inner surface of the porcelain tube with an adhesive has been proposed. However, the difference in thermal expansion between the insulator and the explosion-proof coating makes it easy to peel off, and voids are likely to occur inside the adhesive layer (discharge may occur inside the adhesive layer, reducing the insulation performance). Since the two parts are integrated with adhesive, it has been pointed out that if one cracks, it will propagate to the other, resulting in insufficient explosion-proofing effects.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, has a simple structure, low manufacturing cost, no risk of peeling or voiding of the explosion-proof coating, and moreover, It was developed for the purpose of being an explosion-proof insulator for gas-filled insulating equipment that can minimize the scattering of fragments.

(Means for Solving the Problems) The present invention provides a cylindrical explosion-proof coating made of tetrafluoroethylene resin on the inner surface of an insulator tube used for gas-filled insulating equipment.
It is characterized by the fact that it is directly adhered by utilizing the thermal expansion recovery effect without intervening an adhesive layer.

(Example) Next, the present invention will be explained in detail with reference to the illustrated example.
In Fig. 1, flll is a porcelain insulator tube used for gas-filled insulated equipment, and (2) is a central conductor inserted through the center of this insulator tube il+, whose upper end is connected to the upper end opening of the insulator tube (1). It is held on the lower surface of the upper fitting (3) to be sealed. In addition, the lower end of the insulator pipe (1) is attached to the mounting opening (6) of the case of the gas-filled insulating equipment via the fixing fitting (4) and the ground flange (5). (1) A cylindrical explosion-proof coating made of polytetrafluoroethylene resin with a thickness of 1 to 5 mm on the inner surface (7
) are closely attached. This explosion-proof coating (7) is directly adhered to the inner surface of the insulator tube (1) using its own thermal expansion recovery action without intervening an adhesive. Here, the term "thermal expansion restoration effect" refers to the effect of restoring the synthetic resin tube to its original size when the synthetic resin tube, which has been subjected to a diameter reduction drawing process using a die heated to, for example, about 300 DEG C., is heated after molding. In this way, the diameter-reduced drawing process creates an insulator (1).
A cylindrical body made of tetrafluoroethylene resin with a diameter slightly smaller than the inner diameter of the insulator tube was inserted into the inside of the insulator tube.
When heated to ~300°C, the cylindrical body expands in an attempt to restore its original size and comes into close contact with the inner surface of the insulator tube (1). The variation in the inner diameter of a porcelain insulator tube is about ±3%, and the recovery rate of a cylindrical body made of tetrafluoroethylene resin is up to 20%.
%, it is possible to achieve close contact without using methods such as spot matching, and mass production is possible. The method of heating may be to place the entire insulator tube (1) into a furnace, or to blow hot air into the inside of the cylinder. Curved parts (8) and (9) are formed to absorb the difference in thermal expansion between (1) and the tetrafluoroethylene resin, but these curved parts (8) and (9) can be formed by pressing a mold heated to 100 to 300°C. α is a small hole made through these curved parts (8), (9) or other parts, which allows the explosion-proof coating (7)
) to eliminate the pressure difference between the inside and outside.

(Function) With this structure, even if the insulator tube (1) 1 explodes due to some reason, the cylinder made of polytetrafluoroethylene resin, which has excellent rigidity, remains in close contact with the inner surface of the insulator tube (1). The explosion-proof coating (7) temporarily blocks the dark output of gas from inside, and prevents a large amount of gas inside the insulator tube (1) from being released all at once. Therefore, the scattering of fragments of the insulator tube (1) can be minimized.

In addition, in the present invention, the explosion-proof coating (7) is in close contact with the inner surface of the insulator tube film without an intervening adhesive layer due to its own thermal expansion recovery action, so there is no risk of it peeling off during use, and the adhesive As in the case of using insulator (1)
There is no risk of forming voids in which foreign gas accumulates between the insulation film and the explosion-proof coating (7), and therefore there is no possibility of deterioration of insulation performance due to voids. Furthermore, in the present invention, since the insulator tube (1) and the explosion-proof coating (7) are not integrated with an adhesive, cracks occurring in one of them will not be transmitted to the other, and a sufficient explosion-proof effect can be achieved. It will be demonstrated. Moreover, the explosion-proof coating (7) of the present invention is an insulator film.
The structure is simple because it is closely attached to the inner surface of the device, and unlike conventional models that incorporate an explosion-proof inner cylinder, the overall structure is compact and can be installed in existing equipment without changing its dimensions. be.

(Effects of the Invention) As is clear from the above description, the present invention has a simple structure and is easy to manufacture, yet can produce a sufficient effect of preventing scattering of debris. In addition, in the present invention, cracks do not propagate between the insulator tube and the explosion-proof coating, and it can be easily applied to insulator tubes of any size. There are many advantages that can be applied to Therefore, the present invention greatly contributes to the development of industry as an explosion-proof insulating tube for gas-filled insulating equipment that solves the problems of the prior art.

[Brief explanation of the drawing]

FIG. 1 is a central vertical sectional view showing an embodiment of the present invention. (1): Insulator, (7): Explosion-proof coating.

Claims (1)

[Claims] A cylindrical explosion-proof coating (7) made of tetrafluoroethylene resin is applied to the inner surface of an insulator tube (1) used for gas-filled insulating equipment.
An explosion-proof insulator for gas-filled insulating equipment, characterized in that the above are directly adhered to each other without intervening an adhesive layer by utilizing thermal expansion recovery action.