GB188424A - Improvements in rotary calcining furnaces - Google Patents

Abstract

188,424. Stehmann, H. Aug. 26, 1921. Rotary furnaces; shaft furnaces; cooling discharged materials.-In apparatus for calcining cement, magnesite, &c. comprising a rotary furnace a, which discharges into a shaft c where the cement &c. is cooled by the air to be supplied for combustion in the rotary furnace, the shaft is of such a size, and the air supply and the automatic discharge means are so controlled, that the air will be heated up to the ignition temperature of the fuel before entering the rotary furnace. The lower end of the shaft is enclosed to prevent uncontrolled admission of air and is provided with an automatic discharge device of any known construction. The cooling-air is supplied in part beneath the grate d by the fan f<1> and in part at a higher level in the shaft by a fan f which draws its supply from a jacket e around the lower end of the rotary furnace. The hot air leaves the shaft through the neck g where it meets a further supply of air drawn from the jacket e and delivered by a fan f<2> through the conduit g<1>. The clinkering of the material may be completed in the upper part of the shaft, the necessary heat being furnished by fuel supplied through the opening h. When the apparatus is worked in this manner the clinkering zone b may be shortened. The calcining-zone may be divided by longitudinal partitions i into four separate chambers.