GB506123A - Improvements in or relating to gas- or vapour-filled electric discharge devices - Google Patents

Abstract

506,123. Discharge apparatus. PATENTVERWERTUNGS-GES. HERMES. Aug. 8, 1938, No. 23404. Convention date, Aug. 7, 1937. [Class 39 (i)] In a gas- or vapour-filled discharge device, primarily for high voltages, having a number of intermediate electrodes 4, 5, &c., arranged between the anode 3 and the cathode 2 for rendering uniform the potential distribution between the anode and the cathode and/or for de-ionizing, the intermediate electrodes, and if necessary, any control electrodes provided such as grids 6, 7 are secured in a tube 32 of quartz or ceramic material which is fitted in the actual discharge vessel 1 and is supported thereby. The object of this arrangement is to avoid damage to the seals due to the heating of the leads when the electrodes are degassed by high frequency heating. The intermediate electrodes and the grids are secured by U- section rings 8 which also serve to prevent discharges in the space between the electrodes and the carrier. The rings are held in the carrier by three screws one of which has a lead wire for the associated electrode. Resilient fmgers are provided to locate the electrodes in the carrier. Each intermediate electrode consists of a number of tubular sections relatively staggered in the axial direction and the central cylinders are closed by partitions 10 to retard the movement of ions. A metal screen 19 surrounding the anode and secured inside the tube has an extension 11 within a groove in the anode to prevent rapidly moving ions from passing to the outside and producing charges on the carrier tube or on the wall of the vessel. The tube is held at its upper end by an annular cap 12 having a tubular part 15 enclosing the base of the upper seal, and the axial position is determined by a resilient ring 16 surrounding the anode lead 17 and insulated by rings 18. Similar means may be employed to prevent axial displacement of the cathode lead. The lower end of the carrier tube is held in a U- section ring 21 having a tubular extension 22 surrounding the base of the lower seal. To prevent discharges along the inner wall of the vessel, thin annular metallic layers 23 are provided in the neighbourhood of the lead-in conductors and preferably conductively connected thereto ; if thicker rings are employed, they should be slotted to avoid heating by induced currents during treatment of the vessel with high frequency current. Metallic caps may also be provided on the leads outside the vessel, and an electrostatic screen 24 surrounds the anode system and may be connected to the anode.