GB394861A - Improvements in luminous electric discharge tubes - Google Patents

Abstract

394,861. Discharge lamps. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London.-(Assignees of Patent-Treuhand-Ges. fur Elektrische Gl³hlampen; 11, Ehrenbergstrasse, Berlin.) Oct. 25, 1932, No. 29862. Convention date, Dec. 14, 1931. [Class 39 (i).] A lamp having thermionic electrodes and a filling consisting of a rare gas for starting in addition to a metal vapour whose pressure during operation is less than the saturation pressure at the temperature of the discharge has a double-walled envelope, neither wall of which is of conductive material, and the electrodes are arranged in the inner space, which is in communication with the outer space. In one construction, an inner wall 8 has widened portions 11, 12 which surround the electrodes 4, 5 and is supported by metal rings 13, 14 secured by stays 15, 16 to rings 17, 18 engaging the foot tubes 2, 3. Screens 19, 20, preferably of mica supported by the lead-in wires 6, 7 protect the foot tubes 2, 3 from excessive heating. The filling may consist of a rare gas together with vapours such as those of alkali metals, magnesium, cadmium or zinc, or with mercury vapour at high pressure. Specification 13567/04, [Class 39, Electric lamps &c.], is referred to.