GB826616A - Improvements in or relating to electric discharge lamps - Google Patents

Abstract

826,616. Discharge lamps. GENERAL ELECTRIC CO. Ltd. Jan. 18, 1957 [Jan. 19, 1956], No. 1887/56. Class 39(1). A discharge lamp of the positive column type having a U-shaped envelope 1 mounted within a single or double-walled jacket 5 and having a filling of alkali metal, and a rare gas, has the limbs 2 of the envelope positioned between two plates 16 of transparent or translucent heat-insulating material such as glass or quartz extending over the whole or major part of the length and width of the envelope. The plates can be in the form of plane rectangles or can be of dished form and the width of each plate can be slightly greater than the width of the envelope over the two limbs. The plates 16 are supported in direct contact with the limbs 2 by four spring clips 18 each having opposed spring fingers 19 which clip over the edges of the plates, and resilient members 20 which extend into contact with the inner surface of the jacket 5 and support the plates against lateral movement. The plates 16 are supported against longitudinal movement with the jacket by two mica discs 13 and 17 which bear against the end of the plates and are supported against longitudinal movement by means of auxiliary starting wires 21 extending along the outer surface of each plate 16 and passing through holes in the discs, the ends of the wires being bent after passing through the holes so as to bear against the discs. The disc 13 is provided with a central hole 14 through which projects the exhaust pipe 15 of the envelope. The ends 24, 25 of the two wires adjacent the electrodes 3 are connected to the mounting wires 8. The wires 8 are each connected to electrode leads 4 by a nickel sleeve 9 which fits over the ends of the wire and leads. The inner surface of the envelope is of sodium resistant glass and the filling comprises neon containing 0À5% by volume of argon at a total pressure of 14 mms., together with about 0À75 grs of sodium. The space between the envelope 1 and single-walled jacket 5 is exhausted and there is provided within the jacket a getter element 22 mounted on a wire 23 sealed into the pinch of the foot-tube 7.