GB508812A - Improvements in insulating beads for supporting electric conductors - Google Patents

Abstract

508,812. Uniting metal to ceramic materials by heat ; refractory substances ; glass manufacture. GENERAL ELECTRIC CO., Ltd., LAIT, J. R., and PIRANI, M. May 23, 1938, No. 15321. [Class 36] [Also in Groups V and XXIII] An insulating-bead supporting a number of wires is produced by forming a ceramic body 1 having a thermal expansion approximating to that of the wires and provided with holes, filling the holes with molten glass 5 also having a thermal expansion approximating to that of the wires and forcing the ends of the wires 4 into the holes. As shown, the holes may comprise wide portions 2 and narrower portions 3, side passages 6 being provided for the escape of air. The glass may be introduced as a solid rod, either into the cold ceramic which is then heated to melt the glass, or into ceramic at a temperature above the melting point of the glass. For molybdenum wires, the ceramic may comprise 64 per cent of alumina, 25 per cent of silica, 7 per cent of beryllium oxide, 2 per cent of magnesia and 2 per cent of thorium oxide and the glass may comprise 54.7 per cent of silica, 20.9 per cent of aluminium and ferric oxides, 13.7 per cent of calcium oxide, 7.7 per cent of boron trioxide and 3 per cent of barium oxide. Alternatively, nickel.- iron wires may be used with steatite.