GB1055849A - Improvements in or relating to rotary kilns - Google Patents

Abstract

1,055,849. Rotary furnaces. R-N CORPORATION. May 24, 1965, No. 21924/65. Heading F4B. Temperature variations and' distributions along the length of an inclined reaction chamber 10 of a rotary kiln for reducing iron ore are obviated by an aluminium outer shell 60 spaced radially from, and rotating with, the reaction chamber to form an insulative warm air space 64. Atmospheric air is admitted to passage 64 at points in the shell 60 adjacent riding rings 20, 22 and a bull gear 32, while slide doors 66, Fig. 2 (not shown), in said shell 60 permit access to adjustable valves 56 in air tubes 54 connecting the air space 65 with the interior of the kiln. During operation of the kiln, reactants are fed from a hopper 40 and a screw feed 38 projecting through a central upper end opening 36 in the reaction chamber 10, while a rich fuel and air mixture is ignited in a combustion chamber 12, the flame therefrom being impelled toward the feed end of the kiln by a fan 44 in an exhaust stack 42. Initially incomplete combustion is achieved near the combustion chamber, complete combustion being achieved along the kiln by the addition of warm air from space 64 through pipes 54, the amount of air admitted to any particular region of the kiln being controlled .by the appropriate valve 56 in conjunction with thermocouples 58 which ascertain the temperature distribution along the kiln's length.