GB361394A - Improvements in and relating to gaseous electric discharge devices - Google Patents

Abstract

361,394. Discharge lamps. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Foulke, T. E. ; 410, 8th Street, Hoboken, New Jersey, U.S.A.) July 21, 1930, No. 21955. Convention date, July 27, 1929. [Class 39 (i).] A gaseous electric discharge device adapted for the generation of ultra-violet rays comprises two parallel metallic electrodes 4, 5, Fig. 1, spaced apart at a distance of 0À5 to 2À0 millimetres within an envelope 1 which is permeable to ultra-violet rays and contains a filling of one or more permanent gases, for example, 75 per cent of neon and 25 per cent of helium at a pressure of about 30 millimetres of mercury, a getter such as an alkaline compound being mounted on or adjacent to the electrodes, and a quantity of vaporizable material such as a pool 6 of mercury being provided as a source of vapour which emits ultra-violet rays on the passage of an electric discharge through it. In the form shown the electrodes 4, 5 consist of cylinders of nickel, iron, magnesium, cadmium, or other material, and a bead 7 of getter material such as the oxide, hydroxide, or carbonate of an alkali or alkaline-earth metal is mounted on one of the leading-in wires 3. The electrodes may be V-shaped with their closed ends adjacent to one another. In a modification the lead 2<1>, Fig. 4, supporting the electrode 4 is extended downwardly into the mercury pool 6<1>, so that a glow discharge which is initiated between the electrodes 4, 5 extends downwardly to the surface of the mercury. Instead of, or in addition to, mercury for producing ultra-violet radiations other materials such as the chlorides or other halides of caesium, magnesium, or mercury may be used.