Surge arrester

Abstract

A surge arrester includes a gas-tight discharge chamber that is formed by at least one insulating body and two electrodes. The electrodes extend into the discharge chamber and include an electrode spacing with respect to one another and a wall spacing with respect to the insulating body inner wall. The electrode spacing is equal to twice the wall spacing or is less than twice the wall spacing.

Claims

1. A surge arrester comprising: a gas-tight discharge chamber formed by an insulating body, the insulating body having a wall and end faces at ends of the wall; and only two electrodes, wherein the two electrodes extend into the discharge chamber and comprise an electrode spacing with respect to one another and a wall spacing with respect to an inner wall of the insulating body, wherein the electrode spacing is less than or equal to twice the wall spacing, wherein each electrode comprises a base region arranged at one of the end faces of the insulating body, and a pin-shaped free end that extends into the discharge chamber, wherein the base region is embodied in an essentially disc-shaped manner, wherein the wall spacing is a spacing between an outer side face of the free end and the adjacent inner wall of the insulating body, and wherein the electrode spacing is a spacing between outer faces of the free ends facing each other.

2. The surge arrester according to claim 1, wherein the base region comprises an elevation arranged at a portion of the base region that is located between the end face of the insulating body and the free end.

3. The surge arrester according to claim 1, wherein the base region comprises a plurality of elevations that are arranged in a circumferential manner at a portion of the base region that is located between the end face of the insulating body and the free end.

4. The surge arrester according to claim 1, wherein the inner wall of the insulating body of the discharge chamber does not have an ignition strip.

5. The surge arrester according to claim 1, wherein the insulating body has a hollow cylindrical shape.

6. The surge arrester according to claim 1, wherein the surge arrester has a response voltage greater than or equal to 10 kV.

7. The surge arrester according to claim 1, wherein the discharge chamber comprises a gas charge that comprises nitrogen.

8. The surge arrester according to claim 7, wherein the gas charge comprises nitrogen and oxygen.

9. The surge arrester according to claim 1, wherein the electrode spacing is between 8 mm and 16 mm and the wall spacing is between 5 mm and 9 mm.

10. The surge arrester according to claim 1, wherein the electrodes are arranged in a mirror symmetrical manner.

11. A surge arrester comprising: a gas-tight discharge chamber formed by an insulating body; and only two electrodes, wherein the electrodes extend into the discharge chamber, wherein each of the electrodes comprises a base region arranged at an end face of the insulating body, and a free pin-shaped end that extends into the discharge chamber, wherein the electrodes are arranged in a mirror symmetrical manner, wherein the electrodes comprise an electrode spacing with respect to one another and a wall spacing with respect to an inner wall of the insulating body, the electrode spacing being less than or equal to twice the wall spacing, wherein the wall spacing is a spacing between an outer side face of the free end and the adjacent inner wall of the insulating body, and wherein the electrode spacing is a spacing between outer faces of the free ends facing each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above described arrangements are further explained hereinunder with reference to exemplary embodiments.

(2) The drawings described hereinunder are not to be regarded as being true to scale, on the contrary the illustrations can be enlarged in individual dimensions, reduced or also distorted.

(3) In the drawings:

(4) FIG. 1 illustrates a perspective view of an exemplary embodiment of a surge arrester; and

(5) FIG. 2 illustrates a sectional view of this surge arrester.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

(6) FIG. 1 illustrates a perspective view of a surge arrester 1. This surge arrester comprises a hollow cylindrical insulating body 5. A first electrode 7 and a second electrode 13 are arranged on the end faces of the hollow cylindrical insulating body and the electrodes define a hollow chamber inside the surge arrester 1; this hollow chamber is used as a gas-tight discharge chamber.

(7) Only the base regions 11, 17 of the electrodes 7, 13 that seal the insulating body in order to form the gas-tight discharge chamber are evident in FIG. 1.

(8) FIG. 2 illustrates a sectional view along the longitudinal axis 21 through the surge arrester 1 that is illustrated in FIG. 1.

(9) The surge arrester 1 comprises a gas-tight discharge chamber 3 that is formed by the hollow circular cylindrical insulating body 5 and the first and the second electrode 7, 13 that are arranged on the end faces of the hollow circular cylindrical insulating body. The insulating body 5 can also have a different shape with a hole or a recess. The insulating body is produced from a non-conductive material, by way of example a ceramic material.

(10) The first and the second electrode 7, 13 have in each case disc-shaped base regions 11, 17 and also free ends 9, 15 that protrude into the discharge chamber 3 so that the free ends 9, 15 protrude into the chamber that is encompassed by the insulating body 5. The base region 11, 17 is connected to the insulating body 5 in such a manner that the hollow chamber is sealed in a gas-tight manner. The outer contacting of the surge arrester 1 is performed by way of the outer faces of the base regions 11, 17.

(11) The free ends 9, 15 are arranged in the center of the base regions 11, 17. The free ends protrude into the discharge chamber 3 and are aligned with respect to one another. The gas discharge occurs between the free ends 9, 15. The free ends 9, 15 are embodied in a pin-shaped manner. In this exemplary embodiment, the free ends have a circular cylindrical shape. Other shapes, by way of example a conical shape, are also feasible. In this exemplary embodiment, the free ends 9, 15 have a head region 10, 16 in which they are chamfered. Other embodiments of such a head region 10, 16 have other shapes that reduce the cross section, by way of example a tip, edge or step.

(12) In this exemplary embodiment, the base regions 11, 17 comprise annular circumferential elevations 19 that extend into the discharge chamber 3 and the elevations are arranged between the region that is arranged on the insulating body end face and the free end 9, 15. Alternatively, multiple round, linear or other shaped elevations 19 are also feasible that are arranged in a circumferential manner on the insulating body inner wall 23. This elevation 19 or rather elevations render it possible during the assembly process to precisely position the electrodes 7, 13 on the end faces of the insulating body 5. The elevation 19 extends as far into the discharge chamber interior as the free end 9, 15. Such elevations 19 can be produced by way of example by punching or stamping.

(13) The electrodes 7, 13 can be metal, wherein different materials can be used for the base region 11, 17 and the free end 9, 15. The renders it possible to optimize the material in terms of the different electrode regions and their functions.

(14) In this exemplary embodiment, both the insulating body 5 and also the electrodes 7, 13, in particular their free ends 9, 15, are embodied in a rotational symmetrical manner about the longitudinal axis 21 of the surge arrester 1. In addition, this exemplary embodiment is embodied in a mirror symmetrical manner. In particular, the elevations 19 and/or the base regions 11, 17 can deviate with respect to their shape or rather their base surface area from the rotational symmetrical shape. Base regions 11, 17 that have a rectangular base surface area or a base surface area that is straight on one side are also feasible in order to facilitate the assembly of the component.

(15) The electrode spacing L is defined between the end faces of the free ends 9, 15 of the electrodes 7, 13, the electrode spacing extends in this exemplary embodiment parallel to the longitudinal axis 21. The free ends 9, 15 comprise a wall spacing a with respect to the insulating body inner wall 23. The wall spacing a is the spacing between the outer face of the free end 9, 15 and the adjacent insulating body inner wall 23; the wall spacing extends in this exemplary embodiment in a perpendicular manner with respect to the longitudinal axis 21. The electrode spacing L is selected so that it is equal to twice or at least less than twice the wall spacing a, in other words L=<2*a. This condition is also to be fulfilled in the case of free ends 9, 15 and/or an insulating body 5, the diameters of which vary along the longitudinal axis 21, for the different wall spacings beyond the connection site with or the transition to the base region and also preferably in the head region of the free ends.

(16) Further characteristic variables of the surge arrester are its height H, which is measured between the outer faces of the base regions 11, 17 of the electrodes 7, 13 and its diameter D, which corresponds to the outer diameter of the insulating body 5.

(17) The outer diameter D of such a surge arrester 1 can be by way of example 30 mm to 36 mm, the height H 22 mm to 36 mm. The electrode spacing L can be between 8 mm and 16 mm and the wall spacing a between 5 mm and 9 mm.

(18) Such a gas-filled surge arrester 1 can have response voltages of 17 kV to 34 kV and is suitable for use in the case of operating alternating voltages of 10 kVrms to 20 kVrms. The gas charge can comprise nitrogen or gas mixtures with nitrogen and oxygen.

(19) According to the IEC 60099-1 Standard, such a surge arrester gas has a loading capacity of 22 pulses of 10 kA and 8/20 s, two pulses of 100 kA and 4/10 s and also 20 pulses of 250 A and 2000 s.

(20) It is to be noted that the features of the embodiments and exemplary embodiments can be combined.