GB440426A - Improvements in and relating to metallic vapour lamps and gaseous discharge devices - Google Patents

Abstract

440,426. Discharge apparatus. FREEDMAIN, P., 6, Hillside Gardens, Highgate, London. June 26, 1934, No. 18875. [Class 39 (i)] Metallic-vapour lamps and gas-discharge devices, preferably of the kind described in Specifications 313,726, 313,729, and 329,627, [all in Class 39 (i)], comprise outer and inner vitreous envelopes 2, 3 joined by a vitreous tube 4 open at its outer end, and the space within the envelope 3 is completely separated from that between the envelopes 2, 3 and is exhausted through a tube 10 fixed to a closure member 7 between the ends of the tube 4. Conductors 8, 13, 21 may be sealed through the member 7, through the tube 4 between its outer end and the member 7, and through a pinch seal in the envelope 3. The space between the envelopes 2, 3 may contain resistances, capacities or inductances and is exhausted through a tube 26 joined to the tube 4 between its outer end and the member 7. As shown, the envelope 2 contains an incandescent filament 16 and the envelope 3 contains a main anode 9, a vaporizable, metallic pool, arc cathode 19 with an insulator well 20 and a starting anode 24 operated by a thermostatic strip 25. In modifications, the inner envelope contains a smaller envelope, or several small vitreous envelopes are mounted within the outer envelope using separate re-entrant tubes or a single branched reentrant tube.