GB609030A - Improvements in sintered bodies for direct welding to metal parts - Google Patents

Abstract

609,030. Jointing metal to ceramic materials ; insulator bushings. AKT.-GES. BROWN, BOVERI, & CIE. Sept. 21, 1945, No. 24554. Convention date, Oct. 5, 1944. [Class 36] Sintered bodies for use as insulator bushings for direct welding or soldering to the metal casings of mercury arc converters (stated to be applicable also for use as oil-tight bushings for other electrical apparatus such as switches, transformers, and condensers) consist of conductive and non- conductive materials, the end portions being wholly conductive and the proportion of non- conductive material increasing to a maximum at the median zone. As shown in Fig. 1, the electrode 2 of an arcrectifier is hermetically insulated between the metal casing 1 and the flange 3, by concentric elements 4a, 4b, consisting of pulverized metal, e.g. iron, and pulverized, insulating material, such as oxides of sodium, potassium, magnesium, calcium, barium, strontium, zirconium, titanium, thorium, silicon ; minerals such as paolin, soapstone, talc, felspar, or glass or porcelain. Fig. 2 shows a modification built-up in sections 41, 42, 43, in which the welds between the individual elements may serve as bushings for the leads of control-grids or auxiliary electrodes. The sintered bodies may be coated or impregnated with oil, resin, enamel glaze, or synthetic resin; or, the space between the concentric bodies may be filled with an insulating-fluid having a low vapourpressure. To faciliate pressing and withdrawal from the moulds, and to prevent oxidation of the metal component, the pulverized materials are preferably moistened with oil.