GB339559A - Improvements in and relating to electron discharge devices - Google Patents

Abstract

339,559. British Thomson-Houston Co., Ltd., (Assignees of Acheson, M. A.). Feb. 21, 1029, [Convention date]. Vacuum tubes.-Anodes forming part of the envelopes of transmitting valves, particularly generators of very high frequency oscillations, comprise spaced concen. tric cylinders 21, 24, Fig. 1, joined at their upper ends, the lower end of the cylinder 21 being closed to form a chamber for the electrodes which are supported from the other end of the envelope, and the lower end of the cylinder 24 being ring- sealed to the glass 1 to re-enter the envelope. The sealing-ring 23 may be integral with, and of larger diameter than, the cylinder 24 and in line with the envelope as shown or the ring may extend outwardly from the cylinder 24 and be sealed to a short re-entrant part of the glass 1. A partition 25 and chamber 29 may be provided for cooling the anode by circulating water, oil or air. The cylinder 24 may be longer or shorter than the cylinder 24. Within the cylinder 21 are successively a helical scrceen-grid 20 on a collar 7 with a side-lead 12, a helical control grid 19 on a collar 8 with a, side-lead 11, and a cathode comprising two V -shaped filaments 15 connected to flexible leads 17. A sufficient distance along the surface of the glass between the grid lead and the anode is thus obtained with short electrodes and electrode supports, and interelectrode capacity is thus reduced. The screen-grid 20 may be omitted. The Specification as open to inspection under Sect. 91 (3) (a) comprises also modifications in which the cylinder 24 is replaced by a glass tube 34, Fig. 3 (Cancelled), sealed to the top of the cylinder 21 by a ring 23 and in which the chamber 21. is shortened to form a hemisphere. This subject-matter does not appear in the Specification as accepted.