Sparkgap chamber with arc stretching teeth embodying optimum heat sink means

Claim 2

In a sparkgap assembly comprising an insulating housing having means defining an arcing chamber therein, a pair of horngap electrodes mounted in spaced-apart relationship within said chamber to form a sparkgap therebetween at the point of their closest juxtaposition, said horngap electrodes each having an arc-running surface, the respective arc-running surfaces of said electrodes being arranged to diverge from each other and away from said sparkgap, whereby an arc formed across the sparkgap is driven electrodynamically outward along said surfaces, and circuit means electrically connected to said electrodes for applying a surge voltage to them that is sufficient to develop an arc across said sparkgap; the improvement comprising arc-cooling means positioned around a predetermined portion of the periphery of said arcing chamber outward from the more widely separated ends of said electrodes, said arc-cooling means comprising a wall means having a plurality of arc-stretching teeth integrally formed with one side thereof, each of said teeth having a predetermined mean width and being spaced from the tooth next adjacent to it a distance less than the measure of said mean predetermined width.

Claim 3

An invention as defined in claim 1 wherein said plurality of teeth comprises at least four teeth, and said wall means and teeth define a generally arcuate surface the ends of which are respectively adjacent the outer ends of said electrodes.

Claim 4

An invention defined in claim 2 wherein a major portion of said generally arcuate surface is occupied by said teeth, whereas a minor portion of said generally arcuate surface is formed by the respective areas of said wall means between said teeth.

Claim 5

An invention as defined in claim 1 wherein each of said teeth has a substantially equal mean length and said mean length is no greater than 133 percent of said mean width.

Claim 6

An invention as defined in claim 4 wherein the thickness of said wall means outward from the base of said teeth is substantially equal to the measure of the mean length of one of said teeth.

Claim 7

An invention as defined in claim 5 wherein the mean length and mean width of each of said teeth is substantially equal.

Claim 8

An invention as defined in claim 5 wherein eacH of said teeth has a pair of generally flat, side walls that taper toward one another at the outer ends thereof, and the outer end of each tooth also comprises a generally flat surface.

Claim 9

An invention as defined in claim 7 wherein said generally arcuate wall means and said teeth are rigidly formed of an integrally molded, porous, granular insulating material that includes passageways through which arc-generated gases are vented from said chamber.

Claim 10

A surge voltage arrester having a sparkgap assembly comprising an insulating housing having means defining an arcing chamber therein, a pair of electrodes mounted in spaced-apart relationship within said chamber to define a sparkgap therebetween, circuit means electrically connected to said electrodes for applying a surge voltage to them that is sufficient to develop an arc across said sparkgap, and heat-sink means mounted around the periphery of said arcing chamber in a position where at least a portion of said heat-sink means is exposed to direct contact by arcs driven outward from said sparkgap across the chamber, said circuit means including electromagnetic means mounted adjacent said chamber for electrodynamically driving an arc outward from the sparkgap toward said heat-sink means, said sparkgap assembly being mechanically pre-set to have a maximum switching surge sparkover voltage of N volts, said electromagnetic means being operable with said heat-sink means to extinguish an arc formed in said sparkgap at a voltage level less than N volts and greater than 85 percent of N volts after discharging a system switching surge, and said heat-sink means being effective to prevent any dynamic voltages across said assembly after its initial sparkover from exceeding the maximum pre-set switching surge sparkover voltage of N volts of the sparkgap assembly.

Claim 11

A surge voltage arrester having a sparkgap assembly comprising an insulating housing having means defining an arcing chamber therein, a pair of electrodes mounted in spaced-apart relationship within said chamber to define a sparkgap therebetween, circuit means electrically connected to said electrodes for applying a surge voltage to them that is sufficient to develop an arc across said sparkgap, and heat-sink means mounted around the periphery of said arcing chamber in a position where at least a portion of said heat-sink means is exposed to direct contact by arcs driven outward from said sparkgap across the chamber, said circuit means including electromagnetic means mounted adjacent said chamber for electrodynamically driving an arc outward from the sparkgap toward said heat-sink means, said sparkgap assembly being mechanically pre-set to have a maximum switching surge sparkover voltage of N volts, said electromagnetic means being operable with said heat-sink means to extinguish an arc formed in said sparkgap at a voltage level less than N volts and greater than 85 percent of N volts after discharging a system switching surge, and said heat-sink means being effective to prevent any dynamic voltages across said assembly after its initial sparkover from exceeding the maximum pre-set switching surge sparkover voltage of N volts of the sparkgap assembly.