GB1108772A - High pressure electrical discharge lamps - Google Patents

Abstract

1,108,772. Discharge lamps. MINISTER OF TECHNOLOGY 7 May, 1965 [28 July, 1964], No. 30012/64. Heading H1D. A high pressure discharge lamp includes a tubular envelope having an outer jacket, and pair of olectrodes respectively in good thermal contact with a pair of hallow supporting members sealed into opposite ends of the envelope, the arrangement being such that coolant may be passed through the two supporting members and through the outer jacket. In a high power xenon lamp, the tungsten electrodes 1 and 3, of which the conical cathode 3 has a thoriated tungsten wire welded to its tip, are positioned by alumina spacers 29, 31 and brazed into copper. cups 5, 7 which are themselves brazed to the ends of the cupro-nickel tubes 9, 11. The electrodes are each separately cooled by fluid circulated through the tubes 9, 11, via tubes 45, 49. The silica envelope 21 is sealed to the tubes 9, 11 Within the copper caps 13, 17, and is independently cooled by fluid circulated through the silica cooling jacket 33, which has inlet and outlet pipes 39, 41 and is sealed to the outer copper caps 15, 19 by epoxy resin, lead, or wax. The envelope is exhausted, and filled with xenon at 20 1b./sq. inch, through the tube 32. In another embodiment (the Figure accompanying the Complete Specification, not shown), a single supply of coolant feeds both the cooling jacket 33, and-via apertures in tubes 9, 11-the two electrodes, the header assemblies for the cooling system being detachably sealed by 0-ring joints and compression collars.