Four pour la préparation de l'uranium par magnésiothermie

996,816. Bell-type furnaces. COMMISSARIAT A L'ENERGIE ATOMIQUE. June 24, 1963 [July 6, 1962], No. 25064/63. Heading F4B. A bell furnace, for the preparation of uranium by magnesiothermic reduction, comprises a fixed, refractory base 1, a crucible 7 mounted on a system which is height adjustable, and a removable bell 13 covering said crucible and adapted to rest on the base 1 in leak-tight manner, said bell being provided with heating elements and safety devices which prevent the start of the reaction until the bell is in position on the base 1. The base 1 is supported by pillars 2 on the bottom 3 of a well. A support 4 mounted on jacks 5 passes through a central bore in base 1. The upper face of said support is provided with a metallic plate 26. Secured to plate 26 is a hollow metallic tube 27 which transmits vibrations of plate 26 to a loudspeaker 29 through a probe 28 and an amplifier thereby providing a means of detecting the start of the reaction. The crucible 7, which stands on plate 26, is provided with top and bottom closure plates. The bell 13 is provided with three electric heating elements which are mounted one above the other and supplied with current through contact pins 22 which fit inside sockets 23 when the bell is positioned on the base 1. The leak-tight joint is formed by the penetration of an annular flange 24, provided at the bottom of the bell 13, into a sand packing 25 in the base 1.