Heavy duty overvoltage power gap

Claim 2

A three electrode power gap comprising, in combination, a hollow insulator housing of circular cross section closed at both ends by pressure relief diaphragms, a pair of massive hollow spirally slotted cylindrical main metallic electrodes coaxially mounted in said insulator housing with respect to each other and with respect to the axis of said insulator housing and extending toward each other from the opposite ends of said insulator housing so as to provide a main power arc gap between their adjacent ends near the center of said housing, a cylindrical sheet metal shield and trigger electrode mounted in said insulator housing coaxially and symmetrically with respect to said main electrodes and between them and the inner walL of said insulator housing, the ends of said shield having inturned edges extending toward each other and forming a circular gap therebetween near the middle of said shield, and an electrical terminal for said shield extending through the wall of said insulator housing, the arch striking distance between the inturned edges of said shield and their respectively adjacent main electrode being less than the length of said main power arc gap.

Claim 3

A gap as in claim 1 with a conductive spike extending radially inwardly from said shield to near the center of the gap space between said main electrode for increasing the field emission of said shield when its polarity is negative with respect to a main electrode.

Claim 4

A normally sealed power gap as defined in claim 1 provided with means for freely venting it to the atmosphere.

Claim 5

A gap as in claim 3 in which the venting means in transparent diaphragm to permit visual inspection of the interior without dismantling.

Claim 6

A power gap for operation at atmospheric pressure comprising an elongated hollow insulator housing, a pair of metalic caps mounted respectively over opposite ends of said housing to seal said ends, a pair of main electrodes mounted respectively on said metallic caps, the inner ends of said electrodes being spaced apart to form a spark gap therebetween, each of said electrodes being hollow metallic cylinders the walls of which are slotted helically thereby to form said walls into at least two helical current conducting paths, said helical paths being effective to produce a tangential force on the arc root of any arc formed between the main electrodes for rotating the arcs on the electrodes to distribute and minimize burning and melting effects thereon so as to contribute to a high discharge current rating with minimum damage per operation, in combination with means defining an opening in the central portion of at least one of said metallic caps, a frangible pressure relief diaphragm seated in said opening thereby to seal it, said diaphragm being transparent and substantially coaxial with said electrodes thereby to afford means for visually inspecting the interior of said power gap electrodes without dismantling the gap.

Claim 7

A power gap for operation at atmospheric pressure comprising an elongated hollow insulator housing, a pair of metalic caps mounted respectively over opposite ends of said housing to seal said ends, a pair of main electrodes mounted respectively on said metallic caps, the inner ends of said electrodes being spaced apart to form a spark gap therebetween, each of said electrodes being hollow metallic cylinders the walls of which are slotted helically thereby to form said walls into at least two helical current conducting paths, said helical paths being effective to produce a tangential force on the arc root of any arc formed between the main electrodes for rotating the arcs on the electrodes to distribute and minimize burning and melting effects thereon so as to contribute to a high discharge current rating with minimum damage per operation, in combination with means defining an opening in the central portion of at least one of said metallic caps, a frangible pressure relief diaphragm seated in said opening thereby to seal it, said diaphragm being transparent and substantially coaxial with said electrodes thereby to afford means for visually inspecting the interior of said power gap electrodes without dismantling the gap.

Claim 8

A sealed but freely vented power gap as defined in claim 5 provided with a heat shield extending over a large portion of the interior so as to increase the discharge current rating of the gap.