GB592470A - Improvements in or relating to the construction of high power electric vacuum tubes - Google Patents

Abstract

592,470. Thermionic valves. STANDARD TELEPHONES & CABLES, Ltd., GOOD. CHILD, F. D., and EVERETT, K. E. May 16, 1945, No. 12314. [Class 39 (i)] In a high-power electron discharge device having a glass envelope portion 1, Fig. 1, to which a cup-shaped glass base 4 is sealed by a butt-seal around the rim of the cup, the filament is mounted on two end-supporting rods 8, 9, Fig. 2, and a third central supporting rod 16, the control grid is secured to at least three symmetrically arranged supporting rods 13, 14, and 15, and the filament and control grid supporting rods either directly, as shown, or through further supporting rods to which they are connected, are secured in the cup-shaped glass base 4 ,by means of glass beads There may be two cup-shaped glass bases 4, 5, sealed at 6 and 7 to each end of a glass envelope 1, as in the pentode arrangement shown in Fig. 1, the filament 24, control grid and screen grid being mounted on the base 4 and the suppressor grid and anode 36 on the base 5. The cathode 24 is mounted on a hook assembly 25, and is tensioned by a spring 26, the control grid is carried on rods 27 fixed to a collar 28, the screen grid is carried on rods 29, the suppressor grid on rods 34, and the anode 36 on a collar 37, the members 25, 26, 28, 29, 34 and 37 being supported by rods sealed in the cup-shaped glass bases 4 and 5, Figs. 1, 2 and 4, Some of the supporting rods 12, 14, 15, 16 and 19 sealed in the bases 4, 5 do not pass through to the outside of the valve. The . free ends of the rods 29 are connected by a detail 30 carrying insulating bushings 31 for steadying the control grid rods 27, and the free ends of the rods 34 are carried in insulating bushings 35 fixed to the screen grid supports 13, 14 and 15. Gauze screens 32, 33 are fixed to the screen-grid rods 29 at either end. An exhaust tube 23 is provided. Figs. 6 and 7 show a triode having a metal anode 38 forming part of the envelope which may be enclosed in a cooling jacket (not shown), the anode 38 being sealed to a tubular glass portion 40 to which the glass base 42 is butt-sealed at 41. The control grid is mounted by supports 47 on an annular metal disc 46 which in turn is supported by three symmetrically arranged heavy conductors 43, 44, and 45. Outside the glass base 42, the conductors 43, 44, and 45 are secured to a conductive ring 52 on which is mounted an annular disc 53 of insulating material by means of three flat metal strips 54, 55, and 56. These strips are united at the centre and connected to a plug terminal 57. Two plug terminals 58, 59 for the filament are mounted on the disc 53 and are connected to the filament leads 48, 49 by strips 60, 61 respectively. A water-cooled pentode may be constructed on similar lines. A triode arrangement similar to that described with reference to Figs. 6 and 7, but designed for forced air cooling is described with reference to Figs. 8 and 9 (not shown).