IMPROVEMENTS IN OR RELATING TO A PROCESS FOR CALCINING LIMESTONE OR DOLOMITE AND TO A SHAFT FURNACE THEREFOR

摘要

1,206,845. Shaft furnaces. RHEINISCH-WESTFALISCHE KALKWERKE A.G. 15 Aug., 1968 [16 Aug., 1967], No. 39046/68. Heading F4B. A combustion air supply through different sectors of a cooling zone of a shaft furnace 12, in which limestone or dolomite is calcined, is regulated in dependance on temperature variations across the furnace shaft in the compensation zone (not shown), to promote even burning over the whole furnace cross-section. Air for both cooling and combustion, from blower 14, is supplied both centrally through pipe 1 and supply inlet 2, and through radial pipes 11 supplied through branch pipe 15 and annular header 10. Dampers 13, 16 and 17 regulate the air flow to the various furnace sectors. In a modification (Fig. 1, not shown) the air supply to each of the radial pipes is from an independant blower separate from that used to supply the central pipe and supply inlet. Adjustable dampers again give control of the flow through each pipe. In another embodiment, Fig. 5, regulation of the air supply to the furnace sectors is effected by cable operated segmental valves 25 mounted in the supply inlet 2. Alternatively (Fig. 4, not shown) a rotary slide valve may replace the segmental valves or else (Fig. 3, not shown) the various sectional outlets of the supply inlet 2 may each be connected to an independently operable blower.