GB194133A - Improvements in and relating to electric conductors suitable for sealing into vitreous material - Google Patents

Abstract

194,133. British Thomson-Houston Co., Ltd, (General Electric Co.). March 2, 1922. Leading-in wires.- To make a seal for a conductor passing through fused silica, a tubular extension 8 is formed in the silica with a conductor 10 enclosed in it, and a metal covering 12 is cast around the extension 8, then the extension and the metal covering are cut through to expose the conductor, and a metal cap 14, Fig. 4, is fused in position to cover the end of the conductor and connect it to the metal 12. If the conductor fits tightly into the bore of the silica, as shown in Fig. 4, the metal 12 has a coefficient of expansion greater than that of silica, and so compresses the silica tube on to the conductor 10 in cooling. If there is a space for admission of metal between the conductor and the silica, as shown in Fig. 6, a metal having a coefficient of expansion less than that of silica is chosen. An enlargement 14<1> may be formed in the tubular extension adjacent the main body of the vessel 9 to minimize risk of breakage. In a modification, the cast metal may itself form the conductor, as shown at 15, Fig. 7, this construction being suitable for making contact with a body of mercury &c. Specification 21383/05 is referred to.