GB372526A - Improvements in or relating to electric discharge tubes provided with a metal sleeve - Google Patents

Abstract

372,526. Discharge apparatus. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, 13D, Emmasingel, Eindhoven, Holland. April 16, 1931, No. 11339. Convention date, April 16, 1930. [Class 39 (i).] In high-tension discharge tubes, such as X-ray tubes and valves, in which a metal vessel 1, Fig. 1, surrounds the discharge space and is insulated from the electrodes 4, 5 by portions 2, 3 of the vacuum-tight wall having equal insulating capacities, a metal sleeve 7 surrounding the tube is connected to the vessel 1 through a solid or gaseous resistance to anchor the potential of the vessel and to discharge static changes from it without directly earthing it. The vessel 1 may form part of the envelope of the tube as in Fig. 1 or may be a conducting coating of the envelope. The sleeve 7 may support the tube and may be earthed. The conductivity of the resistance may increase with the current through it or with the temperature. The resistance may conduct only above a certain voltage and may be a semiconducting layer 8 between the vessel 1 and the sleeve 7. In a modification, the vessel and sleeve are separated by insulating cylinders and joined by an auxiliary spark-gap or enclosed glow-discharge gap. In Fig. 3, the resistance is a spirally wound wire 21 drawn out coaxially and embedded in an insulating mass 24.