GB789071A - Electrode for electric discharge tubes - Google Patents

Abstract

789,071. Cathode constructions. LUMALAMPAN AKTIEBOLAG. April 22, 1954 [April 24, 1953], No. 11683/54. Class 39(1). Electrode for discharge tubes, particularly fluorescent lamps, has a carrier for electronemissive material comprising a core of coiled wire and a wire coil of the same wire diameter, coil diameter and pitch as the core coil wound on the core to form a coiled coil on the envelope of the core coil. The core and the coil wound round it may consist of two or more coiled wires, which in the case of two coiled wires can be wound in opposite directions. The core and the coil wound round it can be completely filled with emissive material, e.g. 6 mgs. of BaCOs, with the possible exception of the ends of the carrier which can act as anode extensions when the electrode serves as anode. In an example of forming the electrode a tungsten wire is wound on a molybdenum mandrel and another tungsten wire of the same diameter and pitch is wound in the opposite direction. The coil so formed is divided into two parts, one for the core and the other for the coil wound round it, which are subjected to the normal annealing and mandrel dissolving processes. Dimensions are given.