GB414611A - Improvements in luminous sources formed by electric discharge tubes - Google Patents

Abstract

414,611. Discharge lamps. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London.-(Assignees of Patent Treuhand Ges. fur Elektrische Gl³hlampen; 11, Ehrenbergstrasse, Berlin.) March 14, 1934, No. 8071. Convention date, March 15, 1933. [Class 39 (i).] A lamp is formed of two or more tubes housed in a common container 20 ; one or more low voltage tubes working at mains voltage of not more than 260 volts and one or more working at substantially higher voltage. The low voltage tube 5 is of the high pressure metal vapour type such as a mercury lamp working at a pressure exceeding 50 mms., preferably several hundred millimetres ; it has thermionic electrodes 6, 7 and it may have a starting electrode 10. The high voltage tube 11 surrounds the tube 5 and has a filling of rare gas and sodium. The heat from the tube 5 assists in raising the temperature of the tube 11. The high voltage tube may be fed from a transformer secondary, the low voltage being in series either with this lamp or it may be with the transformer primary. A reflector may be provided for the lamp and the transformer may be housed in an extension of the reflector. Specifications 290,583, [Class 39 (i)], and 397,006 are referred to.