JPH0579819U - Lightning protection insulator lid mounting structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a structure for mounting a lightning protection insulator lid, in which the lid is not broken when the porcelain lid is joined. [Structure] In this lightning protection insulator, an accommodating cylinder portion 8 is formed in a porcelain shade portion 6, and in the accommodating cylinder portion 8, a current limiting element 10 having a non-linear voltage-current characteristic is accommodated. The porcelain lid 12 is inserted into the openings of both ends of the accommodating cylinder 8 via the inorganic adhesives 11 and 13.
14 is attached. The adhesive areas of the porcelain lids 12, 14 and the end faces of the porcelain lids 12, 14 are substantially aligned. Further, at least the inner surfaces of both ends of the accommodating tubular portion 8 are formed in a perfect circle, and the end surfaces of the bonding area and the porcelain lids 12 and 14 are substantially concentric with each other.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lightning insulator lid mounting structure that discharges a lightning surge current to the ground, suppresses a rise in a lightning surge potential of a transmission line, and prevents a power failure due to a ground fault.

[0002]

[Prior Art]

 Generally, in this type of lightning protection insulator, a housing cylinder is integrally formed with a cap made of porcelain, and a current limiting element mainly composed of zinc oxide, for example, which has a non-linear voltage-current characteristic is formed inside the housing. The housing is housed, and a lid made of porcelain is bonded and fixed to the upper and lower opening surfaces of the housing cylinder through low melting glass.

A high-frequency induction heating device is used to melt the low-melting glass when heating and joining the housing cylinder and the porcelain lid. In this joining method, a low-melting-point glass is calcined in a circular ring shape on the back surface of the porcelain lid, and the porcelain lid is applied to the end surface of the accommodating cylinder so that the low-melting glass coincides with the end surface of the accommodating cylinder. The low-melting glass is melted by heating with the harmonic induction heating device, and the porcelain lid is fixed to the accommodating cylinder by cooling and solidifying the glass.

[0004]

[Problems to be solved by the device]

 However, when the insulator is fired, the accommodating cylinder is often deformed from a perfect circular shape to an elliptical shape.If the accommodating cylinder has an elliptical shape, minute cracks are formed in the glass during the cooling process of the low melting point glass. However, there was a problem that the cracks were transmitted to the porcelain lid and the porcelain lid was broken.

That is, if the housing cylinder has an elliptical shape, the region of the low-melting-point glass having a perfect circular ring shape and the end surface of the housing cylinder do not match. Therefore, the bonding area between the end surface of the housing cylinder and the low melting point glass has a different radial dimension of the lid depending on the location. Therefore, the amount of shrinkage of the low-melting glass due to cooling differs depending on the location, and the above-mentioned cracks occur.

The present invention has been made by paying attention to the problems existing in the above-mentioned prior art, and its purpose is to provide a structure for attaching a cover body of a lightning protection insulator which does not cause destruction of a lid when joining a porcelain lid. To provide.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, in the first invention, an accommodating cylinder part is formed in the porcelain capsular part, and a current limiting element having a non-linear voltage-current characteristic is accommodated in the accommodating cylinder part. In the lightning protection insulator in which the porcelain lid is attached to the openings at both ends via an inorganic adhesive, the gist is that the adhesive region of the porcelain lid and the end surface of the porcelain lid are substantially aligned.

In the second invention, the gist is that at least the inner surfaces of both ends of the accommodating cylinder portion are formed into a perfect circle, and the end surfaces of the bonding region and the porcelain lid are substantially concentric.

[0009]

[Action]

 With the above structure, the accommodating cylinder portion and the bonding area of the porcelain lid substantially match. Therefore, the shrinkage of each part of the bonding area during the cooling process is uniform, and the occurrence of cracks can be suppressed.

[0010]

【Example】

 An embodiment in which the present invention is embodied in a suspension type lightning protection insulator will be described below with reference to FIGS. 1 and 2.

As shown in FIG. 2, a head portion 2 having a cylindrical shape with a lid is integrally formed on the central upper portion of the insulator body 1, and a cap metal fitting 4 is provided on the outer peripheral portion of the head portion 2 with a cement 3 interposed therebetween. Fitted and fixed. In addition, a pin fitting 5 is fitted inside the head 2 and is adhesively fixed by cement 3. A fold portion 7 is formed on the lower surface of the cap portion 6 of the insulator body 1. By engaging the end of the pin metal fitting 5 with the cap metal fitting 4 of another lightning protection insulator, a plurality of lightning protection insulators can be connected in series in the vertical direction. An accommodating cylinder portion 8 is integrally formed at one place or a plurality of places of the cap portion 6 so as to penetrate vertically.

An upper ceramic lid 12 is heat-bonded and fixed to the upper end surface of the housing cylinder portion 8 with a low melting point glass 11 serving as an inorganic adhesive. A lower porcelain lid 14 is also heat-bonded and fixed to the lower end surface of the mounting tube portion 8 with a low melting point glass 13 interposed therebetween. The inner surfaces of both ends of the accommodating cylinder 8 are sintered and cut into a perfect circle, and stepped portions 9 are formed on the inner surfaces of both ends. A plurality of current limiting elements 10 together with a protective tube 28 are housed and arranged inside the accommodating tube portion 8. The current limiting element 10 is formed of a resistor whose main component is zinc oxide whose voltage-current is nonlinear. ing. The protective tube 28 is a tubular body made of an inorganic material such as inorganic fiber or alumina, and is set between the current limiting element 10 and the housing tubular portion 8. The purpose is to protect the explosion proof when a large current flows through the current limiting element 10. The pair of intermediate electrodes 15 and 16 are arranged in the intermediate portion of the current limiting element 10, and a spring 17 for urging the current limiting element 10 toward both upper and lower ends is interposed between the intermediate electrodes 15 and 16. It is equipped. Electrode plates 18 and 19 are interposed at the upper and lower ends of the current limiting element 10.

A pair of upper and lower electrodes 20 and 21 made of a metal material such as copper or kovar are fixed to the electrode plates 18 and 19. Both electrodes 20, 21 penetrate the porcelain lids 12, 14 and project outward.

Therefore, the current limiting element 10 is electrically connected to the electrode plates 18 and 19 and electrically connected to the electrodes 20 and 21. The upper lead wire 22 is attached between the upper electrode 20 and the cap fitting 4, and the current limiting element 10 and the cap fitting 4 are electrically connected via the upper lead wire 22 and the upper electrode 20. There is. The lower lead wire 23 is attached between the lower electrode 21 and the pin fitting 5, and the current limiting element 10 and the pin fitting 5 are electrically connected via the lower lead wire 23 and the lower electrode 21.

The method of attaching the porcelain lids 12 and 14 in the above-described structure is as follows. First, the porcelain lids 12 and 14 are pre-baked on the outer periphery of the back surface so as to form a perfect circular ring. Next, as shown in FIG. 1, the electrode plate 18 provided with the electrodes 20 is supported by the upper porcelain lid 12, and the portion of the low melting point glass 11 of the porcelain lid 12 is supported on the end surface of the housing cylinder 8. In this state, since the inner surface of the accommodating tube portion 8 is cut into a perfect circular shape, at least the inner surface thereof and the region of the low melting point glass 11 coincide with each other on a concentric circle. Although not shown, a means for supporting the electrode plates 18, 19 on the porcelain lids 12, 14 is provided between the porcelain lids 12, 14 and the electrode plates 18, 19 or the electrodes 20, 21. .. Next, a local heating device 26 including a graphite susceptor 24 and an induction coil 25 wound around the outer circumference of the porcelain lid 12 is placed and heated via a metal plate 27.

When the heating device 26 is operated to transfer the heat generated in the graphite susceptor 24 to the metal plate 27, the porcelain lid 12 is heated and the low-melting glass 11 is melted by the heat, and the housing cylinder 8 And the porcelain lid 12 are hermetically joined. In this way, the one porcelain lid 12 or 14 is joined and fixed to one end of the housing tubular portion 8. Similarly, the other porcelain lid 14 or 12 is also joined and fixed to the other end of the housing cylinder 8.

At the time of this joining and fixing, since the region of the low melting point glass 11 and the inner peripheral edge of the housing tubular portion 8 are concentrically associated with each other, the radial distance between them is the same.

As described above, after the insulator is sintered, the inner surfaces of both ends of the housing tube portion 8 are cut and formed into a perfect circle, so that the stress is uniform, and the glass shrinkage occurs during the cooling process of the low melting point glass. Accompanying cracks do not occur, and the porcelain lid 12 does not break.

The present invention is not limited to the configuration of the above-described embodiment, but may be configured as follows, for example, within a range not departing from the spirit of the invention. (1) In the above-described embodiment, the inner surface of the accommodating cylinder portion 8 is cut and formed into a perfect circle, but the same effect can be obtained by forming the porcelain lids 12 and 14 into elliptical shapes so as to be fitted to the accommodating cylinder portion 8.

(2) In the above embodiment, only the inner surface of the accommodating cylinder portion 8 is cut and formed into a perfect circle, but in addition to this, the outer peripheral surface can also be formed into a perfect circle.

[0021]

[Effect of the device]

 According to the present invention, it is possible to prevent cracks in the low melting point glass, reduce destruction of the porcelain lid, and improve yield.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a suspension type lightning arrester embodying the present invention.

FIG. 2 is a semi-longitudinal sectional view of the suspension type lightning arrester.

[Explanation of symbols]

6 cap part, 8 housing cylinder part, 10 current limiting element, 11, 13
Low melting glass as an inorganic adhesive, 12, 14 Porcelain lid.

Claims (2)

[Scope of utility model registration request] 1. A porcelain-made cap portion is provided with an accommodating cylinder, and a current limiting element having a non-linear voltage-current characteristic is accommodated in the accommodating cylinder, and an inorganic adhesive is interposed between both ends of the cylinder. A lightning protection insulator having a porcelain lid attached thereto, wherein an adhesive region of the porcelain lid and an end surface of the porcelain lid are substantially aligned with each other. 2. The lightning protection insulator according to claim 1, wherein at least the inner surfaces of both ends of the accommodating tubular portion are formed into a perfect circle so that the end surfaces of the bonding area and the porcelain lid are substantially concentric. Lid mounting structure.