GB411257A - Improvements in or relating to electron discharge tubes - Google Patents

Abstract

411,257. Thermionic valves. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, 13D, Emmasingel, Eindhoven, Holland. March 21, 1933, No. 8522. Convention date, June 3, 1932. [Class 39(i).] In a valve having one or more grids at least two of the electrodes are mounted close to each other and are clamped between insulating members mounted on supports fixed to the pinch, so that the electrodes and insulating members form a rigid unitary structure. The electrodes may be of ferro-chromium which may be readily united to insulators of glass, on the insulators may be of magnesia. In one form, Fig. 1, a flat indirectly-heated cathode 2 is coated on its upper side with emissive material and is mounted on a metal member 5 by means of strips 5<a>. Metal strips 6 engage the lower end of insulators 7. A grid 8 parallel to the cathode is held by the insulating members 7, 9, whilst the anode 12 is clamped, by means of strips 13, between insulators 9 and 14. The anode is also supported by rods 15 one of which serves as the lead-in. The grid lead is taken off at 10. Screws 16 with nuts 17 bolt the whole structure together. The electrodes may be spaced 0.5 mm. apart or less. According to the Specification as open to inspection under Sect. 91 and as shown in Fig. 3 (Cancelled) an electrode system may be spaced by disc-or ring-like insulators 22 with central apertures for the indirectly-heated cathode 23 and stepped portions engaging respectively the parallel-wire grid 27 and the two anode plates 29, which are extended through apertures in the upper insulator and tied by a rod 31. The anode leading-in wire skirts the lower insulator as shown at 30. This subject-matter does not appear in the Specification as accepted.