Extended lifetime railgap switch

Claim 1

In a railgap switch of the type having an elongate blade electrode made of conductive material, an elongate housing made of insulating material for supporting said blade eletrode and plate electrode in opposed relation extending in the same direction with the blade centered over the plate and separated therefrom by a gap, and a gas filling said housing and said gap, said gas being selected to breakdown and switch from a highly insulative state to a highly conductive state upon application of a high voltage across said blade and plate electrodes, the improvement comprising: forming said blade with laterally extending transverse wing portions at the edge of said blade and adjacent said gap so as to extend in spaced parallel relation to the surface of said plate, said blade generally following the contour thereof to form an inverted T-shape structure with said wing portions extending transversely of the elongate dimension of the blade, said wing portions terminating in a pair of spaced parallel edges extending along the elongate direction of said blade to thereby create two spaced elongate edges along which arcs form serving to divide the erosion effects of discharge between them, the current through each edge being one-half of that in single-edge devices with ablation wear reduced accordingly to give significantly larger switch lifetime, said blade and wing portions limiting ablation erosion of said edges in a direction generally aligned with the plate contour so that the edge-to-plate separation remains substantially constant.