GB354082A - Improvements in and relating to the sealing of conductors into electric apparatus - Google Patents

Abstract

354,082. Insulators. B R I T I S H THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Soc. GÚnÚrale de Constructions Electriques et MÚcaniques Alsthom; 146, Avenue des Champs Elysees, Paris.) Sept. 4, 1930, No. 26458. Convention date, Sept. 4, 1929. [Class 36.] In order to prevent overheating of a metallic conductor which is sealed into electrical apparatus by basalt or similar vitreous material, the seal is augmented by a superimposed plastic joint covered by a liquid such as mercury, and the conductor is provided with a sleeve portion to which the insulator is fused and which furnishes an annular recess extending at least the length of the joint. To prevent oxidation the surface of the metal to which the insulator is fused is coated with a protective non- oxidizing layer such as nickel or enamel. The example shows the anode 17 of a mercury vapour rectifier supported by a rod 16 which has a metal sleeve 1 secured to and surrounding its upper end, leaving a cooling space 19, the basalt insulator 2 being moulded to the sleeve. The surface of the joint between the sleeve 1 and insulator 2 is covered by a plastic ring 3 upon which a non-distortable metal ring 4 is pressed, preferably by screws 5 with interposed flexible washers 6. Two half-rings 7 located within a recess or groove 8 in the sleeve 1 abut against and take the pressure from a ring 9 into which the screws 5 are secured. A surrounding cylinder 12 rests upon a plastic joint 13 similar to the joint 3, and a cover-plate 11 is secured in position by nuts upon gudgeon pins 10 which are mounted upon the ring 9. A quantity of mercury 14 which covers the plastic joint is introduced into the annular chamber formed by the co-operating sections, the level of the mercury being ascertained by a float 15. Specification 344,680 is referred to.