FIELD: crucible or pot furnaces. SUBSTANCE: multi-chamber apparatus includes rectangular housing with transverse partitions dividing it into chambers with drain holes for overflow of material; these holes are provided with gas distributing grids forming undergrid and above-grid space; apparatus is also provided with loading device mounted in first chamber and overflow lip; apparatus is provided with transverse partitions dividing the above-grid space of second and subsequent chambers into sections; these partitions are provided with lower overflow holes located near gas distributing grids; lower edge of each subsequent (in way of motion of material) drain hole for overflow of material from chamber to chamber is located below subsequent one; ratio between distance from gas-distributing grid to lower edge of drain hole which brings cavities of above-grid spaces of first and second chambers in communication and height of overflow lip ranges from 1.2 to 2.5; height of partitions dividing above-grid space into sections exceeds height of overflow lip by 2 to 5 times. Total area of drain holes which communicate adjacent chambers is equal to 2 to 15 percent of area of cross section if chamber at level of overflow lip. EFFECT: enhanced reliability. 2 cl, 2 dwg
