GB351641A - Improvements in and relating to means for the automatic regeneration of the vacuum in vacuum containers - Google Patents

Abstract

351,641. Maintaining high vacua. INTERNATIONAL GENERAL ELECTRIC CO., Inc., 120, Broadway, New York, U.S.A.-(Assignees of Allgemeine Elektricitats Ges.; 2, Friedrich Karl-Ufer, Berlin.) April 24, 1930, No. 12694. Convention date, April 24, 1929. [Class 8 (i).] The vacuum in a container more particularly a high vacuum switch container is maintained by making use of a relay, controlled by the positive ion current which flows when the pressure reaches a predetermined limit, which connects a heating device for the vaporization of a regenerating substance such as calcium, barium, or magnesium. The container 15 has an extension in which a glass tube 1 containing the regenerating substance is situated, and an extension 5 enclosing a grid 13, a filament 12, and an electrode 14. When the vacuum in the container is reduced, a sufficient current flows between the grid 13, and the electrode 14, to operate a relay 4, closing the circuit of a heating filament 2 and resulting in the vaporization of the regenerating substance which reduces the pressure in the main container. An electrode 7 may be introduced close to the filament 2 and positively charged with respect to it, so that the emission of electrons from the filament 2 is accelerated to bring about ionization of the gases and vapours. The electrode 7 may be continuously charged or only when the relay 4 operates. To prevent the vaporization of the regenerative substance in the tube 1 during the initial evacuation of the container 15, the tube is at first sealed and heated by means of the filament 2 to open at a weak spot 3 after the container 15 has been treated.