GB450063A - Improvements in and relating to dual purpose thermionic tubes - Google Patents

Abstract

450,063. Thermionic valves. ROGERS RADIO TUBES, Ltd., 100, Sterling Road, Toronto, Canada. Oct. 19, 1935, No. 28925. Convention date, Nov. 6, 1934. [Class 39 (i)] A valve has a high mu triode section in the upper part of the envelope 1 and a power pentode section 30 in the lower part both supported from the press 32 provided with a cap 2, which carries the contact prongs 3- 9 ; two transverse metal plates 19, 20 screen the two sections from one another, and are welded to two standards 23 24. A common cathode body 13-with internal heater-has two separated coatings 14, 15 of emissive material; the upper end of the cathode body is connected by a lead 25 to the standard 23, the lower end to the standard 24, and the pentode shield grid to the standard 23, so that this grid, the cathode body and screen plates 19, 20 are electrically connected. Resistance coupling between the two cathode coatings is dispensed with. The triode anode 12 has an opening 16, which permits inspection of the triode and facilitates degasification during forming. The grid lead from the triode is taken through the upper end 10 of the envelope; the anode lead consists of a small diameter tungsten wire 27 coated with aluminium oxide or other ceramic material and passes through an aperture in a mica spacer 28 for the electrode structure. The spacer is stayed by a strut 35 from the pentode anode. A cooling vane 31 is welded to the standard for the control grid of the pentode. The envelope has a metal coating 41 such as described in Specification 414,193.