GB399715A - Improvements in or relating to gas filled electric incandescent lamps having spirally shaped incandescent elements - Google Patents

Abstract

399,715. Electric incandescent lamps with residual gases. VEREINIGTE GLUHLAMPEN UND ELECTRICITATS AKT.-GES., Ujpest, near Budapest. March 7, 1933, No. 6908. Convention date, April 12, 1932. [Class 39 (ii).] A gas-filled electric incandescent lamp with a spiral shaped incandescent element contains a proportion of dry iodine, either in the form of vapour or in solid form, for example as an iodine compound which is subsequently vaporized within the bulb, for the purpose of preventing internal arc discharges. The iodine may be dried by sublimation of solid iodine, or it may be mixed with phosphorus pentoxide and heated. Dry iodine may be produced within the lamp itself, for example by coating the leading-in wires with an iodine compound from which the vapour is liberated when the lamp is in operation. Preferably a phosphorus iodine compound, such as phosphorus tri-iodide or phosphorus iodide, is employed, thereby producing a drying action in addition to preventing internal arc discharges, so that the usual heating of the lamp during the pumping operation or during sealing off may be dispensed with.