GB191111140A - Improvements in and relating to Vapour Electric Devices. - Google Patents

Abstract

11,140. British Thomson-Houston Co., [General Electric Co.l. May 8. Low-pressure metallicvapour apparatus. - A mercury - vapour apparatus has an inner envelope of silica or other refractory material, as described in Specification 13,567/04, and is so arranged that, on tilting, the electrodes are connected by the mercury in the inner space only, discharge through the outer space being thus prevented. In the apparatus shown in Fig. 1, the leading-in wires 6, 7 pass through orifices in the inner vessel 2; when the left-hand end is raised, the mercury in the outer vessel breaks contact with the leading-in wire at that end before making contact with the mercury at the other end. An orifice 3 connects the vapourspaces of the inner and outer vessels. The cathode connexion 5 consists of a chain of platinum, tungsten, or other heavy metal which does not readily alloy with mercury. The lower half of the tube 2 may be grooved longitudinally to facilitate starting. In a modification, the cathode end of the inner tube is open, and dips into the mercury in the corresponding limb of the outer vessel. In another modification, Fig. 4, the anode is a solid disk 14 in the inner tube, and the part of the leading-in wire exposed between the two tubes is protected by a small silica tube 13. The apparatus may be tilted automatically by a shunt magnet with a series cut-out.