GB432442A - Improvements relating to electrical discharge tubes - Google Patents

Abstract

432,442. Discharge tubes. QUARZLAMPEN-GES., Hanau, Germany. Feb. 17, 1934, No. 5331. Convention date, Feb. 17, 1933. [Class 39 (i)] A gas- or vapour-filled discharge tube, such as a lamp, has one or more electrodes E which are heated to an electron - emitting temperature during operation and are each surrounded by a metal jacket M, which is electrically insulated therefrom, is not maintained at any fixed potential, and is supported on, but insulated from, an electrode leading-in wire by means of a glass bead G. The tube may be adapted to emit visible or invisible rays and the filling consists of an unsaturated vapour such as cadmium or mercury. Starting may be facilitated by a filling of argon and the provision on the tube wall of a strip which is connected to the electrodes and is interrupted in the neighbourhood of the cathode. The electrode E consists of two or more nested cups e.g. of nickel, between which electron-emitting, material is located or, alternatively, it may consist of plaited wire or ribbon having projections and hollows which house the electronemitting material. The jacket may be fitted with an apertured cover for the passage of the discharge, and is located, at least at one point, less than 5 mm. from the electrode so that it may be heated, to remove occluded gas, by a heavy discharge between the electrodes. In another form, the jacket has the shape of a frustum of a cone. The Specification as open to inspection under Sect. 91 states also that the jacket may be supported by members fused to the side tube wall or by a leading-in wire passing through the end of the tube. This subjectmatter does not appear in the Specification as accepted.