GB418027A - Improvements in and relating to gaseous electric discharge devices - Google Patents

Abstract

418,027. Discharge apparatus. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.- (Assignees of Foulke, T. E. ; 30, Evelyn Place, Nutley, New Jersey, U.S.A.) July 1, 1933, No. 18738. Convention date, July 1, 1932. [Class 39 (i).] A tube contains two main electrodes, one heated to emit electrons, an auxiliary anode adjacent the heated electrode, and a conductor extending from a point near the non- heated electrode to the auxiliary anode, to which it is connected. In one form, a tube 20 contains a cup-shaped anode 21 and a cathode 23 having a heater 24 and heatshields 25, 26, the inner surfaces of which, beyond the cathode are coated with powdered aluminium, or other material resisting activation by sputtered particles. A ring- shaped auxiliary anode 30 is mounted above the cathode on a shielded support 31 and is connected to a bariumcoated conductor 32 extending to a point near anode 21 and having a support 33. The filling may consist of neon, helium, argon, nitrogen, mercury or the like alone or in combination, for example neon with 0À2 per cent of argon at 2 to 4 mms. Specification 395,851 is referred, to. The Specification as open to inspection under Sect. 91 describes also a tube having a cylindrical cathode with an axial rod connected to it through a resistance and terminating near the anode, a tube for use with alternating-current having two such cathodes and auxiliary electrodes, and a tube as shown in the Figure with the member 32 spaced from the ring 30 and with another cathode similar to cathode 21 replacing anode 21. The cathode and the member 32 may in all cases be coated with barium azide which is reduced to barium in the induction furnace. The wire 32 is heated by means of an inductive discharge in the evolved gas, and the furnace is moved along as the gas is evolved, the tube being on the pump. The electrodes are left coated with barium cemented on by barium nitride and a little unreduced azide. Metallic caesium or other alkali metal may then be distilled on from a pellet. Alternatively the electrodes may be coated by the method described in Specification 411,669. The tube may be filled with neon and 0.01 to 1 per cent of argon at a pressure of 1-3 mm. This subject-matter does not appear in the Specification as accepted.