GB129022A - Improvements in or relating to Mercury Vapour Lamps. - Google Patents

Abstract

129,022. Cornu, M. J. Sept.. 25, 1916, [Convention date]. Arc lamps.-A thickwalled silica tube, which is full of mercury when cold, communicates with a closed cathode pocket and an anode pocket in which movement of the mercury is strongly damped by a valve. The thickness of the wall of the arc tube is at least half its internal radius. Cooling-bulbs b, e, the latter of which may be provided with radiating-gills, are interposed between the lighting-tube i and the electrode pockets. A tube d. the narrow end of which projects into the middle of the anode bulb c, is covered by the lift valve g depressed by a coiled leading-in wire h. The working pressure in the lighting tube is predetermined by regulating the height of the mercury in the anode bulb and the initial gae pressure, but is always greater than atmospheric pressure. If the anode bulb is sealed, the gas pressure varies automatically with the electric pressure. Starting may be effected by heating the mercury-filled lighting tube i at its upper bent end k by an external gas flame or series coil of platinum. Alternatively, a capillary tube may lead upwards from the bend k to a bulb containing a series, shunt, or independent heating-coil, or to a cylinder and spring-urged piston which can be depressed either by hand or by automatic electric means to force nitrogen, argon, neon, or a vapour into the arc tube.