GB743373A - A device for the heat-treatment of loose material - Google Patents

Abstract

743,373. Shaft furnaces; preheating charge materials. BERZ, M. Feb. 22, 1954 [Sept. 2, 1953], No. 24258/53. Class 51 (2). [Also in Group XIII] Apparatus for burning, calcining, sintering, drying or preheating loose granular material, e.g. cement raw material, comprises vertical concentric casings of circular or polygonal shape defining an interspace charged from above with the loose material and closed by a bottom wall, discharge ports spaced around the foot of the inner casing opposite reciprocating rams disposed around the outer casing, and means for introducing hot air or hot gases into the interspace in counter-current to the charge material. Fig. 1 shows the invention applied to a shaft furnace in which the interspace formed between the outer casing a and the inner casing b is closed by a bottom wall d extending inwardly to form a central opening f through which discharged material falls into a shoot g leading into a cooler i having an air-permeable grate h and a discharge drum k. Combustion air introduced by the pipe m into the upper part of the shoot g above the plug of discharged material formed therein, enters the interspace through the discharge ports e or at varying heights in the shaft through valve controlled branches off a central pipe o. Additional air may be introduced, through pipes n into the casings containing the reciprocating rams c. Fig. 2 shows a drier and preheater of generally similar construction to the furnace shown in Fig. 1 attached to a rotary furnace s. The shaft is closed and charge material is distributed over the interspace by a rotary pocketed drum p and a rotary shoot r, hot gases from the furnace which enter the interspace at various heights as shown by the arrows being removed by an offtake r. The interspace cross-sectional area may be increased upwardly or downwardly. In a modification, Fig. 3 (not shown), the rams are disposed in the wall of the inner casing b, and the discharge ports in the outer casing a, the lower part of the apparatus being surrounded by a jacket which merges into a hopper connected to the rotary furnace s.