GB927395A - Improvements relating to the transmission of electric current between conductor members of solid and liquid forms respectively - Google Patents

Abstract

927,395. Switch contacts. J. SAYERS. July 3, 1959 [July 3, 1958], No. 21281/58. Drawings to Specification. Class 38 (5). [Also in Groups XXXV and XXXVI] In a device which involves the transmission of current between a solid and a liquid member both made of electrically-conductive material, the solid member incorporates at its current communicating face a solid electrically-conductive barrier layer of a material which does not form an amalgam with or otherwise react physically or chemically with the liquid so that destructive erosion of the solid conductor by the liquid is avoided or reduced, and the barrier layer outer surface is either coated with a further layer of an electrically conductive material which is wetted by the liquid or is treated by a flux or etching agent to promote wetting by the liquid. The device may be an electric switch in which the liquid and two solid members are in an insulating container a change of orientation of which causes the liquid either to bridge, or otherwise, the members. In this case the liquid is mercury, the solid members and the wetting layer are of copper, and the barrier layer is of nickel. Alternatively, the device may be a L.V. high-current switchgear having one or more pairs of fixed contacts, each comprising parallel plates having mercury in the gap between them, and closure of which contacts is effected by respective movable contacts which enter into the gaps. In this embodiment the flux may be zinc chloride and the etching agent may be nitric acid. Specifications 927,394, 927,396 and 927,397 are referred to.