DE102006044992A1 - Three pole spark gap for multipolar overvoltage protection unit, has housing with opening to allow outwards resigning of gas, where opening is formed in wall of housing and is closed by using diaphragm under increased pressure - Google Patents

Abstract

The gap (4) has a housing (3) with an interior (5) forming an outside electrode (6), and an inside electrode (7) extending into the interior of the housing based on a side wall of the housing. The housing has a passage opening at a front wall to allow outwards resigning of gas from the interior of the housing, where the gas arises during ignition of an electric arc. The opening is closed by using a flexibly yielding diaphragm (17) under increased pressure, where the diaphragm is made of plastic e.g. polyoxymethylene plastic, and the housing is formed as a tube section. An independent claim is also included for a multipolar overvoltage protection unit comprising two spark gaps.

Description

The invention is directed to a spark gap comprising a housing and two electrodes, wherein the inside of the housing forms a first electrode and a second electrode projects from an end wall of the housing substantially conically into the interior of the housing, and wherein the housing at least one passage opening has to emerge from the interior of the space formed during the ignition of an arc to the outside and reduce the pressure. Such a spark gap is off DE 198 17 063 C2 known.

These known spark gap works so that the jacket-shaped outer electrode the space in which an arc can stop after ignition, to the outside closed encapsulates, taking on the the free end of the inner Electrode opposite Side of the interior of a transverse to the central longitudinal axis Bottom, wherein between the outer electrode and the inner Electrode is a ring made of plastic with the action of an arc is arranged, which forms the end wall of the housing.

One such overvoltage protection element is not blown due to the closed construction. Nevertheless, will an arc extinguishing mechanism reached, after which the arc accelerates from the foot of the inner Electrode can migrate to the free end, where it is deleted. The shape of the inner electrode results in an increased number potential Ignition points. The rate of migration thus reduces the burnup a variety of arcs. Because at the edge, outside lying region of the inner electrode a ring of when arcing arranged gassing plastic, accelerates the case of arc resulting gas the Wegwandern the resulting arc of the place of emergence.

at the known, extremely advantageous extinguishing properties having a small size Spark gap is the pressure reduction after ignition through an opening very small diameter on the opposite end wall, so on the one hand the character of a closed spark gap maintained and, on the other hand, pressure reduction is nevertheless possible in order to subsequent deletion to allow the arc.

Of these, the invention is based on the object, a spark gap of the generic type to design that their extinguishing behavior is further improved, in particular by an additional Pressure buildup on deletion and achieved a more targeted and faster pressure reduction after extinguishing becomes.

These Task is inventively characterized solved, that on a wall, in particular on an end wall, of the housing a Passage opening formed which is yielding by means of an elastic under increased pressure Membrane is closed. In this case, the housing through a pipe section be formed and the passage opening by its one open end. The training of the housing as Pipe section also has the advantage of a cost-effective Manufacturability.

The Membrane is preferably made of plastic, the pressure and Temperature increase guest, ie e.g. POM.

By the embodiment of the invention will practically created a valve outlet, which in case of sudden pressure increase opens and allows a quick pressure reduction. Because the membrane in turn preferably at temperature increase gas is discharged before the release of pressure, first by the exiting Gas a pressure increase accomplished the deletion favored by the arc.

conveniently, is over the membrane is arranged a pressure plate which defines the membrane and also serve to limit the bulging of the membrane.

to Achieving a simple assembly can be diaphragm and pressure plate an aligned hole for have a fastening screw.

at a multipolar overvoltage protection element comprising a plurality of spark gaps according to the invention in particular be provided that this two juxtaposed spark gap chambers or housing wherein the pressure reduction after ignition of a spark gap over the each adjacent spark gap chamber is made by the membrane the two adjacent electrode chambers and their respective passage opening overlaps.

following The invention is based on a preferred embodiment in connection closer to the drawing explained. Showing:

1 an exploded perspective view of a three-pole spark gap according to the invention,

2 a view of the spark gap after 1 and

3 a section along the line AA in 2 ,

In the drawing is a three-pole overvoltage protection element 1 shown in one with terminals 2 provided outer housing 3 three spark gaps 4 are arranged.

Every spark gap 4 comprises a tubular, at the same time a housing wall forming, an interior 5 surrounding outer electrode 6 and an inner electrode 7 and a plastic wall forming a front wall 8th from POM.

The plastic base 8th has a recess 9 into which a foot 10 the inner electrode 7 can be used until a ring collar 11 above the foot 10 at the front 12 of the pedestal 8th comes to rest and is held accordingly defined.

The base 8th in turn has a ring collar 13 on which the outer, tubular, the housing wall forming electrode 6 rests in the assembled state, wherein between the outer electrode 6 and the inner electrode 7 a distance in the form of a ring gap 14 remains.

The inner electrode 7 has a cone-shaped tip 15 with a rounded end 16 on.

A membrane 17 has the same footprint as the front 18 of the outer casing 3 and is with a circumferential, upwardly projecting edge 19 provided so that an overlying pressure plate 20 to the inner surface 21 the membrane is kept at a distance such that this inner surface 21 at a pressure build-up in the interior 5 can bulge outward.

About a fixing screw 22 and a snap ring 23 as well as drilling 24 . 25 in the printing plate 20 or in the membrane 19 are pressure plate 20 and membrane 19 via a threaded hole 25 at the front 18 of the outer casing 3 established.

In particular from 3 becomes clear that at a pressure build-up in one of the adjacent interiors 5 the membrane 17 or the inner surface 21 is bulged, so that, for example, in the right interior 5 in 3 built-up pressure left in 3 in the local left interior 5 can be reduced.

Claims (7)

A spark gap comprising a housing and two electrodes, wherein the inside of the housing forms a first electrode and a second electrode protrudes from a front wall of the housing substantially conically into the interior of the housing, and wherein the housing has at least one passage opening in order to ignite when ignited an arc resulting gas from the interior to escape to the outside and reduce the pressure, in particular multipolar spark gap, characterized in that on a wall, in particular on an end wall of the housing ( 6 ), a passage opening is formed, which by means of an elastically yielding under elevated pressure membrane ( 17 ) is closed. Spark gap according to claim 1, characterized in that the membrane ( 17 ) consists of plastic. Spark gap according to claim 2, characterized in that the membrane ( 17 ) consists of a gassing at pressure and temperature increase plastic. Spark gap according to claim 3, characterized in that the membrane ( 17 ) consists of POM. Spark gap according to claim 1, characterized in that above the membrane ( 17 ) a printing plate ( 20 ) is arranged. Spark gap according to claim 5, characterized in that membrane ( 17 ) and pressure plate ( 20 ) an aligned bore ( 25 respectively. 24 ) for a fastening screw ( 22 ) exhibit. Multipolar overvoltage protection element comprising at least two spark gaps according to one of Claims 1 to 6, characterized in that it has at least two spark gap chambers ( 5 ), wherein the pressure reduction after ignition of one of the spark gaps ( 4 ) over the respectively adjacent spark gap chamber ( 5 ) takes place by the membrane ( 17 ) the two adjacent spark gap chambers ( 5 ) and whose passage openings overlaps.