GB862982A - Electric discharge device - Google Patents

Abstract

862,982. Electric discharge devices. STANDARD TELEPHONES & CABLES Ltd. June 11, 1957, No. 18339/57. Class 39(1). An electric discharge device comprises an opposed pair of conducting electrode supporting and locating plates and electrodes 4 and/or 'electrode support rods 5 supported by and between the plates and insulated therefrom, one of the plates being relatively rigid and the other providing compliance for the assembly in the direction normal to the pair of plates. The electrodes and/or support rods are located in holes 2, 3 in the plates and slots 12, 13 are provided in the plate 1 between the holes to provide the compliance. The other plate can be made rigid by ribs. The plates are attached at their peripheries to the envelope. The end of each electrode or electrode support rod 4, 5 is coated with a layer of insulating material 6, 7. The layer 6 on the cathode 4 is a coating of ceramic material applied by cataphoresis and sintered. The layer 7 on the grid support rod 5 is a thin ceramic tube metallised on the inside and attached to the rod 5. Eyelets 8 and 9 provided with projecting tags are pressed on to the insulating layers and welded to the plate 1. In the construction shown in Fig. 4, an electrode or electrode support rod 14 is supported by the plate 15. A ceramic tube 16 is provided on the end of the electrode 14 and a metal layer 17 is applied to the ceramic tube, the plate 15 being brazed at 18 to the layer 17. In a modification an insulating layer could be provided on the conducting plate, at least in and around a locating hole, and the electrode attached to the insulating layer. In one example the conducting plate is made of a mixture of ceramic material and powdered metal pressed together and sintered. The surface of the composite material, at least in the neighbourhood of the locating holes is then anodised, the oxide layer so formed providing the insulating layer.