GB410994A - Improvements in luminous electric discharge lamps - Google Patents

Abstract

410,994. Discharge lamps. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London.-(Assignees of Patent-Treuhand Ges. fur Electrische Gl³hlampen ; 11, Ehrenbergstrasse, Berlin.) Aug. 17, 1933, No. 22986. Convention date, Aug. 19, 1932. [Class 39 (i).] In lamps such as those described in Specifications 352,352 and 370,338, in which the discharge is surrounded by a metal enclosure and is viewed along the length of the positive column, a single metal enclosure 6 is divided by a metal partition 9 into two parts each enclosing an electrode 10, 11 and the discharge traverses a tube 12 through the partition 9 and is viewed through a window 13 in the enclosure 6. The enclosure 6 may be a flat rectangular box heated by the discharge to dull red heat and may contain alkaline earth metals reaching an adequate vapour pressure at 600-800‹ C. To keep these metals in the box, the envelope 1 is filled with rare gas at a pressure of several mms. and an extension tube 14 is provided at the window 13. The electrodes 10, 11 may consist of or be coated with materials emitting electrons thermionically and preferably consist of a sintered mixture of refractory metals and alkaline earth oxides. A ring 15 in front of the window 13 may form the anode of a directcurrent lamp using both electrodes 10, 11 as cathodes, or the ring 15 may be used as an auxiliary starting electrode connected to one terminal of the normal supply or of a supply of higher tension. In a modification, the ring 15 is omitted, the partition 9 is diagonal and the tube 12 is vertical.