MULTI-SPARK GAP

Abstract

A multi-spark gap having both a high power-follow current extinguishing capacity as well as a relatively low protective level in which a distance x.sub.1 between a first electrode and an adjacent second electrode, which together form a first individual spark gap, is larger than respective distances x.sub.2 between other adjacent electrode pairs of additional individual spark gaps. The distance x1 is at least 0.5 mm and the distances x2 of the additional individual spark gaps are at most 0.2 mm. Additionally, an ignition aid for igniting the first individual spark gap is provided, which aid has at least a resistive ignition element and a voltage-limiting element, wherein the ignition element is connected to an electric-arc combustion chamber of the first individual spark gap and is electrically connected on the one side to the first electrode and on the other side via the voltage-limiting element to the second contact element.

Claims

1. A multi-spark gap for an overvoltage protector, comprising: multiple electrodes, and insulation elements arranged between the electrodes, wherein the electrodes are arranging in facing pairs each of which forms an individual spark gap, the individual spark gaps being connected in series, two electrically conductive contact elements, between which the electrodes are arranged, so that a first contact element makes electrical contact with a first of the electrodes, and the second contact element makes electrical contact with the last of the electrodes of the multi-spark gap, and a control circuit for controlling the ignition behavior of the multi-spark gap, wherein the control circuit has multiple control elements which are connected to the electrodes, except for the first electrode, wherein a distance x.sub.1 between the first electrode and an adjacent second electrode, which together form a first of the individual spark gaps, is larger than respective distances x.sub.2 between the other pairs of electrodes which form additional individual spark gaps, wherein an ignition aid for igniting the first individual spark gap is provided, which aid has at least a resistive ignition element and a voltage-limiting element, and wherein the ignition element is connected to an electric-arc combustion chamber of the first individual spark gap and is electrically connected on one side to the first electrode and on another side being connected to the second contact element via the voltage-limiting element.

2. The multi-spark gap according to claim 1, wherein the ignition aid has a voltage switch element which is arranged in a series circuit with the resistive ignition element and the voltage-limiting element.

3. The multi-spark gap according to claim 1, wherein, in each case, a first connector of a control element is connected to an electrode of a respective one of the additional individual spark gaps and is connected with a second connector to one another and to the second contact element.

4. The multi-spark gap according to claim 3, wherein a first connector of the voltage switch element is connected in an electrically conductive manner to the second contact element and a second connector of the voltage switch is connected to both the voltage-limiting element and to the second connectors of the control elements.

5. The multi-spark gap according to claim 1, wherein the distance x.sub.1 between the first electrode and the adjacent second electrode of the first individual spark gap is at least 0.5 mm.

6. The multi-spark gap according to claim 1, wherein the distances x.sub.2 between the adjacent electrodes of the additional individual spark gaps are in each case at most 0.2 mm.

7. The multi-spark gap according to claim 1, wherein the distance x.sub.1 is between 1 mm and 2 mm and the distances x.sub.2 between the electrodes of the additional individual spark gaps between 0.05 mm and 0.15 mm.

8. The multi-spark gap according to claim 1, wherein the distances x.sub.2 between the adjacent electrodes of the additional individual spark gaps are essentially the same.

9. The multi-spark gap according to claim 1, wherein the distance x.sub.1 between the first electrode and the adjacent second electrode of the first individual spark gap is at least five times the distance x.sub.2 between the adjacent electrodes of the additional individual spark gaps.

10. The multi-spark gap according to claim 1, wherein the individual electrodes are thin disks of carbon.

11. The multi-spark gap according to claim 1, wherein the insulation elements between the individual electrodes are part of a common insulation and holding arrangement, in which both the individual electrodes as well as the contact elements are arranged.

12. The multi-spark gap according to claim 1, wherein the individual insulation elements between the individual electrodes are in each case part of an individual insulation and holding frame, and wherein the individual insulation and holding frames are connected to one another.

13. The multi-spark gap according to claim 12, wherein the individual insulation and holding frames in each case have a receptacle opening for accommodating a control element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 shows a schematic diagram of a first embodiment of a multi-spark gap, in sectional view, and

[0027] FIG. 2 shows a schematic diagram of a second embodiment of a multi-spark gap, in sectional view.

DETAILED DESCRIPTION OF THE DRAWINGS

[0028] The two figures in each case show a schematic diagram of a multi-spark gap 1 according to the invention, which has multiple electrodes 2 and insulation elements 3 arranged between the electrodes 2. In each case, two electrodes 2 facing one another in this case form an individual spark gap 4, wherein the individual spark gaps 4 in turn are connected in series. The first electrode 21 that is depicted above in the figures' forms with the adjacent second electrode 22 a first individual spark gap 41, which differs from the other individual spark gaps 4 in its design. In addition, the first electrode 21 is electrically connected to the first contact element 5, while the second contact element 6 is connected in an electrically conductive manner to the last electrode 23 of the multi-spark gap 1. All electrodes 2, 21, 22, 23 of the multi-spark gap 1 are thus arranged between the two contact elements 5, 6.

[0029] In the two depicted embodiments of the multi-spark gap 1, in addition, a control circuit 7 is provided for controlling the ignition behavior of the multi-spark gap 1, wherein the control circuit 7 has multiple control elements 8 designed as capacitors, which are connected to all electrodes 2, 22, 23 except for the first electrode 21. In addition, the multi-spark gap 1 has an ignition aid 9, which is used to ignite the first individual spark gap 41. The ignition aid 9 has a resistive ignition element 10 as well as the series circuit that has a voltage-limiting element 11 and a voltage switch element 13. As a voltage-limiting element 11, in particular a varistor can be used, and as a voltage switch element 13, in particular a gas discharge valve can be used. The ignition element 10 is connected to the electric-arc combustion chamber 12 of the first individual spark gap 41. In addition, the resistive ignition element 10 is electrically connected on the one side to the first electrode 21 and on the other side via the series circuit that consists of the voltage-limiting element 11 and voltage switch element 13 to the second contact element 6.

[0030] The multi-spark gap 1 according to the invention is divided into two areas, namely a first area that comprises the first individual spark gap 41 and a second area that comprises the other individual spark gaps 4. Moreover, the first area also includes the ignition aid 9 with the resistive ignition element 10 extending into the electric-arc combustion chamber 12 of the first individual spark gap 41, and the second area includes the control circuit 7 with the individual control elements 8.

[0031] As can be seen from both figures, the distance x.sub.1 between the first electrode 21 and the adjacent second electrode 22, which together form the first individual spark gap 41, is significantly larger than the respective distance x.sub.2 between the other adjacent electrodes 2, 22, 23, which form the additional individual spark gaps 4. The distance x.sub.1 between the first electrode 21 and the adjacent second electrode 22 is preferably between 1 mm and 2 mm, while the distance x.sub.2 between the other adjacent electrodes 2, 22, 23 of the additional individual spark gaps 4 is preferably between 0.05 mm and 0.15 mm. The distance x.sub.1 is thus preferably about ten times as large as the distance x.sub.2.

[0032] Because of the relatively large distance x.sub.1 between the first electrode 21 and the adjacent second electrode 22, the first individual spark gap 41 and thus also the multi-spark gap 1 as a whole have a sufficiently high insulation strength. At the same time, because of the very small distance x.sub.2 between the adjacent electrodes 2, 22, 23 of the additional individual spark gaps 4, the response voltage is considerably reduced in the second area. Because of the ignition aid 9 that is made in addition, the multi-spark gap 1 thus has a very low protective level in the case of simultaneously high power-follow current extinguishing capacity.

[0033] Both in the embodiment according to FIG. 1 as well as in the embodiment according to FIG. 2, the control circuit 7 has capacitors as control elements 8. In principle, however, other control elements can also be used. The first connector 14 of the individual control elements 8 is in each case connected in an electrically conductive manner to an electrode 2, 22, 23, while the second connectors 15 of the control elements 8 are electrically connected to one another. In the embodiment according to FIG. 1, these second connectors 15 of the control elements 8 are directly connected in an electrically conductive manner to the second contact element 6.

[0034] In the embodiment according to FIG. 2, however, the voltage switch element 13 is connected to the ignition aid 9 between the second contact element 6 and the common potential 18 of the second connectors 15 of the control elements 8. This ensured that the control circuit 7 or the individual control elements 8 are only connected in an electrically conductive manner to the second contact element 6 when the voltage switch element 13 has already responded. The control circuit 7 is thus electrically connected to the second contact element 6 only in the case of discharge, ensuring that the insulation property of the multi-spark gap 1 is considerably improved in the second area.

[0035] The embodiments of the multi-spark gap 1 depicted in FIGS. 1 and 2 thus differ in how the ignition aid 9 is actually arranged relative to the control circuit 7. In the embodiment according to FIG. 2, the voltage switch element 13 is connected in an electrically conductive manner with its first connector 16 to the second contact element 6 and with its second connector 17 both to the voltage-limiting element 11 and to the common potential 18 of the second connectors 15 of the control elements 8.

[0036] In the two embodiments, the individual insulation elements 3 are part of a common insulation and holding arrangement 19, which is simultaneously also used for mechanical attaching of the individual electrodes. In addition, the two contact elements 5, 6 are also accommodated by the insulation and holding arrangement 19, so that a relatively compact multi-spark gap 1 can be produced. Because of the very small distances x.sub.2 between the electrodes 2, 22, 23 that form the additional individual spark gaps 4, the multi-spark gap 1 can have multiple electrodes 2, 22, 23, without the dimensions of the multi-spark gap 1 thus being too large between the two contact elements 5, 6. In this case, it is obvious to one skilled in the art that the number of electrodes 2 depicted in FIGS. 1 and 2 is only by way of example, and the multi-spark gap 1 according to the invention is in no way limited to the depicted number of electrodes 2.

REFERENCE SYMBOLS

[0037] 1 Multi-spark gap [0038] 2 Electrodes [0039] 21 First electrode [0040] 22 Second electrode [0041] 23 Last electrode [0042] 3 Insulation element [0043] 4 Individual spark gap [0044] 41 First individual spark gap [0045] 5 Contact element [0046] 6 Contact element [0047] 7 Control circuit [0048] 8 Control element [0049] 9 Ignition aid [0050] 10 Ignition element [0051] 11 Voltage-limiting element [0052] 12 Electric-arc combustion chamber [0053] 13 Voltage switch element [0054] 14 First connector of the control element [0055] 15 Second connector of the control element [0056] 16 First connector of the voltage switch element [0057] 17 Second connector of the voltage switch element [0058] 18 Common potential of the second connectors of the control elements [0059] 19 Insulation and holding arrangement [0060] x.sub.1 Distance between electrodes and the first individual spark gap [0061] x.sub.2 Distance between electrodes and additional individual spark gaps