GB808204A - Improvements relating to processes and apparatus for effecting heat exchange between gases and solid particles - Google Patents

Abstract

808,204. Charging and preheating granular &c. materials. SMIDTH & CO. A.S., F. L. June 13, 1955 [June 11, 1954], No. 17270/54. Class 51 (2). Granular &c. material is preheated and fed into a rotary kiln 1, Fig. 1, by apparatus comprising a series of cyclone separators 3, 5 and 7 traversed in reverse order by granules leaving a preliminary heater 9 in a general counter-current direction to hot waste gases from the kiln, the said gases then entering the heater 9 and passing downwardly through a layer of granules fed on to a continuous conveyer 10 from a hopper 14. The waste gases leave the preheater through an off-take 13, and small material collecting in the preheater is fed to the furnace by a pipe 20. At each stage of its path to the kiln, the granular material is fed into a waste gas duct 2, 4 or 6 leading to a cyclone, and the last cyclone 3 feeds the preheated material into the kiln by a pipe 19. A modification, Fig. 2, has the arrangement of cyclone separators shown in Fig. 1, but the upper and lower runs of the conveyer 10 in the preheater 9 are separated by a partition 22. Part of the charge material is fed by the hopper 14 on to the upper run of the conveyer and part by a screw 28 on to the lower run, from which a plough 23 directs it into a screw 24 feeding it into a shoot 15, where it joins the material from the upper run of the conveyer. The combined material is delivered by the shoot 15 into a nodulizing drum 25, from which most of the material is fed by a pipe 16 into the pipe 6 leading to the cyclone 7. Part of the material is, however, returned by a pipe 27 to the conveyer 10. The conveyer and its casing may be upwardly inclined if desired.