GB838016A - Improvements in or relating to electron discharge devices - Google Patents

Abstract

838,016. Thermionic valves. STANDARD TELEPHONES & CABLES Ltd. Aug. 3, 1956, No. 24073/56. Class 39(1). In a high power electric discharge tube, the control grid 2, cathode 3 and heater lead 6 are supported by coaxial metal sleeves 20, 13, 12 the other ends of which are secured to metal envelope parts 27, 32, 35 of tapering diameter joined to and insulated from one another by vitreous envelope parts 28, 34. Circuit connections are made by spring-fingers to rings 31, 33, 36, secured to the outside of the metal envelope parts. These rings and the electrode - support sleeves, in particular sleeve 20, may be sufficiently massive to provide good thermal and electrical conductivity but they are secured to the envelope parts at relatively sharp edges thus providing a fulcrum about which the envelope parts may hinge so relieving thermal expansion strains. The metal envelope part 27 may comprise two shells to enable the valve to be assembled in two parts. As shown, the anode 21, of comparatively thick copper, forms part of the envelope and is reduced to a thin-walled section at its open end. It is provided with a circuit connecting ring 23 but this may be replaced by a skirted connecting flange, and cooling fins may be bonded to the external anode surface. The envelope is completed by a glass exhaust tubulation 37 protected by a metal cap 38 incorporated with the heater lead terminal 36. The cathode 3 comprises a set of filament wires connected between filament rings 4 and 5, the ring 4 being connected to the current lead 6 through a flange 7 and a set of flexible metal tapes 8.