JP3153034B2 - Insulated pipe with flange - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flanged insulator tube used for a large gas bushing or the like.

[0002]

2. Description of the Related Art Generally, a flange for fixing an insulator tube to a base is cemented to a base portion of a ceramic insulator body, and a flange for mounting equipment is also provided on a head portion of the insulator tube body. . If such a flange is made of a magnetic material such as iron, an eddy current is generated in the flange due to a current flowing through the center conductor of the bushing, and heat is generated.
There is a possibility that a gap may be formed at the joint due to a difference in thermal expansion between the flange fitting and the porcelain, or the strength of the cement may be reduced due to heat generation. For this reason, the flange of the gas bushing insulator tube has conventionally been made of a non-magnetic material such as an aluminum casting or a bronze casting.

However, in a gas bushing for 1000 KV,
The diameter of the flange joint of the insulator tube is about 1.65 times larger than the conventional 500KV insulator tube. For this reason, when the heat generated inside the gas bushing at the time of energization is transmitted to the flange fitting, or when the temperature of the flange fitting rises due to direct sunlight, the absolute value of the thermal expansion amount becomes larger than before in accordance with the enlargement of the body diameter. As a result, in the case of aluminum or bronze casting flanges, the joints become more loose, the joints are bent in a loose state, and when an internal pressure load is applied, the porcelain and metal fittings come into contact locally, resulting in extreme local stress concentration. There is a problem in that the strength of the porcelain tube is reduced due to the properties of porcelain that is weak.

In a gas bushing for 1000 KV, a much larger bending load is applied to the flange portion of the base since the entire length of the insulator tube reaches 10 to 12 m. However, aluminum castings and bronze castings cannot withstand the load applied to the flange at the base of the insulator tube of the gas bushing for 1000 KV, and the flange may be deformed, causing the fitting to shift or the flange to be broken.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and does not cause the strength of the insulator tube to decrease due to the misalignment of the flange even when the temperature of the flange metal rises. It has been completed in order to provide a flanged insulator tube which is unlikely to occur.

[0006]

The present invention has been made to solve the above-mentioned problems, and is characterized in that a high-manganese steel flange containing at least 15% of manganese is attached to a porcelain insulator body. It is assumed that. This high manganese steel contains 0.1-0.6% carbon, 15-35% manganese,
Preferably, it is composed of 1010% of chromium, with the balance being iron and impurities.

The high manganese steel containing 15% or more of manganese used in the present invention has a coefficient of thermal expansion α of 11 × 10 ^−6.
/ ° C or less, a magnetic permeability μ of 1.1 or less, a non-magnetic material, a Young's modulus E of more than 17 × 10 ⁵ kg / cm ² and a rigidity equal to that of ductile cast iron, 0.2%
It has excellent characteristics such as a large proof stress of 16 kg / mm ² .

[0008]

The flanged insulator tube of the present invention is made of non-magnetic, low thermal expansion, high rigidity and high strength high manganese steel containing 15% or more of manganese for the flange attached to the porcelain insulator tube body. Even if the temperature of the flange bracket rises due to the heat generated inside the gas bushing or the direct sunlight during energization, the joint does not loosen. Further, since the flange has high rigidity and high strength, the fitting is hardly displaced due to bending or internal pressure, and the strength of the insulator tube is not reduced. For this reason, there is no possibility of collapse even in the case of receiving vibration due to an earthquake.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the illustrated embodiments. FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a lower end portion thereof. In these figures, 1 is a porcelain insulator main body for a gas bushing for 1000 KV, and 2 is a flange attached to the base thereof. The flange 2 has a serrated portion 3 formed on an inner surface thereof, and a cement 4 filled inside the serrated portion 3.
Is joined to the porcelain pipe main body 1.

The flange 2 is made of a high manganese steel comprising 0.1 to 0.6% of carbon, 15 to 35% of manganese, 2 to 10% of chromium and the balance of iron and impurities. In the examples, a high manganese steel containing 0.25% carbon, 31% manganese and 2.5% chromium was used. This high manganese steel has a magnetic permeability μ of less than 1.1, a thermal expansion coefficient α of 10.5 × 10 ⁻⁶ / ° C. or less, and a Young's modulus E of 17 × 10 ⁵ kg / cm ^2.
It has the above characteristics.

When the insulator tube of the embodiment was compared with a conventional insulator tube of the same size to which a conventional bronze flange was attached, the following results were obtained. First, an internal pressure of 10 kg / cm ² was applied to the inside of the insulator tube to measure how much the flange 2 was displaced in the axial direction with respect to the insulator tube 1. As a result, assuming that the metal fitting displacement of the conventional insulator tube with a bronze flange is 100,
In the porcelain tube of this example, the metal fitting displacement was 70, and a decrease of 30% was confirmed. This is probably because the high manganese steel flange 2 of the example has a large Young's modulus and a small amount of deformation when subjected to internal pressure.

Next, bending loads were applied to the insulator tube in four directions so that a bending stress of 125 kg / cm ² was generated at the base of the insulator tube, and the displacement of the flange 2 due to the bending load was measured. As a result, assuming that the displacement of the conventional insulator tube to which the bronze flange was attached was 100, the displacement amount of the insulator tube of the present example was 75, and an improvement of 25% was confirmed. This is considered to be because the Young's modulus of the flange 2 made of high manganese steel is large and the deformation due to the bending load is small.

Next, when the temperature of the entire insulator tube rises to 80 ° C. due to energization, the temperature rise plus 125 k acting on the base of the insulator tube
The amount of bracket displacement due to bending stress of g / cm ² was measured. Although this value changes depending on the assembly temperature (cement solidification temperature), when the assembly temperature is set to 45 ° C, the displacement of the metal fitting of the conventional product is 100, whereas that of the embodiment product is 60,
% Improvement was seen. This is apparently due to the difference in thermal expansion between high manganese steel and porcelain being smaller than the difference in thermal expansion between bronze casting and porcelain. (Coefficient of thermal expansion of high manganese steel = 10.5 × 10 ⁻⁶ / ° C, coefficient of thermal expansion of porcelain = 7 × 10 ⁻⁶ /
℃, thermal expansion coefficient of bronze casting = 18 × 10 ^-6 / ℃)

[0014]

As described above, since the flanged insulator tube of the present invention has a flange made of high manganese steel, which has not been used as a metal fitting for insulators, a gas bushing at the time of energization is used. Even if the temperature of the flange bracket rises due to internal heat generation or direct sunlight, there is no loosening of the joint or displacement of the bracket. In addition, bending of the porcelain tube and metal fitting displacement due to internal pressure load can be significantly reduced compared to the conventional product,
There is an advantage that a decrease in strength of the insulator tube can be prevented. For this reason, the flanged insulator of the present invention is suitable as a large insulator such as a gas bushing for 1000 KV, and greatly contributes to industrial development.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a lower end portion of the porcelain tube of the embodiment.

[Explanation of symbols]

 1 Insulator body 2 Flange

Claims (2)

(57) [Claims] An insulator tube with a flange, wherein a flange made of high manganese steel containing 15% or more of manganese is attached to an insulator tube body made of porcelain. 2. The high manganese steel according to claim 1, comprising 0.1 to 0.6% of carbon, 15 to 35% of manganese, 2 to 10% of chromium and the balance iron and impurities. Insulated pipe with flange.