GB370443A - Improvements relating to sealing structures for lead-in conductors in electric vacuum apparatus - Google Patents

Abstract

370,443. Vacuum switches; lead -in conductors. BRITISH THOMSONHOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Rankin, W. K.; 267, Highland Avenue, Lansdowne, Pennsylvania, U.S.A.) Dec. 24, 1930, No. 38930. Convention date, Dec. 26, 1929. [Class 38 (v).] Lead-in conductors, such as 4, to the vacuum chamber 1 of electric vacuum apparatus, such as electric vacuum switches, are each resiliently supported in a glass insulating sleeve 32 the end of which are secured, one to the wall of the chamber and the other to the conductor 4 by means of flexible corrugated copper spinnings 33, 34, the conductor being biased by spring- urged bolts 16, on a flange 15 attached to it, so as to press a plate 23 on the end of the conductor within the chamber 1 against an insulating spacer 26. The bolts 16 carry springs 31 which bear against a cap 17 engaging an outer sleeve 19 of insulating material. The conductor 4 is hollow to permit the forced or convection circulation of cooling fluid which enters the outer sleeve 19 through a pipe 38 and leaves through the hollow conductor 4. In the hollow conductor 4 a tube 42 is secured and is expanded at its upper end 43 to form a tight connection with the conductor wall above apertures 41<1> therein which communicate with the outer annular space 41 formed by the sleeve 19. The cooling fluid passes from the pipe 38 through a ring conduit 30 into the space 41, and, moving upwards therein, passes into and down the annular space 44 in the conductor 4 from whence it passes up the pipe 42 out through the end of the conductor. A cupshaped shield 25 secured to the conductor 4 protects the spacer 26 from metallic deposits. The chamber 1 is exhausted through a tube 11 the end of which is closed by a cap 12 the edge of which is sealed by low melting point alloy 14. In an electric vacuum switch the conductor 4 is the fixed contact stud and the movable contact 3 is formed by an arm 5 which passes through a flexible diaphragm 6 to an actuating arm 8. The arm 5 is electrically connected to the chamber casing 1.