GB833956A - A device for tapping fused material of high temperature from a crucible - Google Patents

Abstract

833,956. Crucibles. GERAETEBAUANSTALT. April 8, 1958 [April 19, 1957], No. 11018/58. Class 82(1) [Also in Groups XII and XXII] In a device for tapping a melt 3 at high temperature, e.g. molten metal, from a crucible 2 having a tapping hole in its bottom and a separately heatable tapping funnel 7 in continuation of the said hole, separate means are provided for obturating the hole from above and the lower orifice of the tapping funnel. The crucible 2 (with the coil 4) and the funnel 7 are carried in a frame 5 by ceramic plates 6 and 9, stiffening ribs 18 and 19 being around the coils 8 and 4 respectively, the assembly being closed by electrically non- conductive rings 20 and 21. The crucible and funnel wall is asbestos on the outside and refractory material such as magnesium oxide, tamped in on the inside before sintering the whole. A plug 25 immersible into the melt 3 and a slider plate 10 may obturate the said hole and the lower orifice respectively. The lower orifice may alternatively be obturated by a plug, which may be surrounded by an integral pan of high temperature material, preferably graphite. The plug 25 may be withdrawn completely from the melt, if desired, by means of a rod 24 passing through a vacuum-tight seal 26 with casing 1 which may be filled with a protective gas. The slider plate 10, or plug used in its place, may have heating or cooling means. To melt down the first charge (the plug 25 being then completely withdrawn) by the current in the induction coil 4, the crucible 2 can be closed by a slider plate 10 operated by an arm 12, shaft 13, bevel gears 14 and 15 and a shaft 17 passing through a seal 16, the melt solidifying on the cold slider plate 10 and the cooled walls of the funnel, to form a stopper therein. After melting is completed, addition of alloy constituents, degassing or like treatment, the slider plate 10 is swung away and the stopper melted by the induction coil 8. To regulate or stop the jet while pouring, e.g. into a chill mould 22, the orifice is suitably obturated by the plug 25. A last portion of the melt is solidified in the funnel 7 to form a stopper for the next charge, the plate 10 is swung away and the crucible 2 is recharged for a new melt. The furnace may be open and/or have a different kind of heating. Specification 812,216 is referred to.