GB1347102A - Rotary kiln for the production of a granular expanded product - Google Patents

Abstract

1347102 Rotary kilns DANSK LECA AS 19 April 1971 [27 Jan 1970 5 May 1970] 20153/71 Heading F4B Expanded clay granules, passing from the drying zone 2 of a rotary kiln to a downstream firing zone 3, are heated from 300-400‹ C. to 800-900‹ C. in an intermediate heating zone including a central gas flow tube 4e, 4f, whereby the majority of the kiln flue gases are kept out of contact with the clay granules which at this stage pass through the annulus 5. The zones 2, 3 may form part of a single structure (Fig. 6, not shown) or be independently rotatable in which case the steel gas flow tube may, as shown, be formed of two parts each secured to one of the kiln zones, or may comprise a single part secured only to zone 3 (Fig. 1, not shown). The gas flow tube may be formed from an assembly of channel members 15, Fig. 9, bolted together, to which may be bolted or welded longitudinal or helical, continuous or discontinuous lifter blades 13 which extend into the mass of granules 14 to transfer heat from the flue gases thereto. The blades, which extend between 1/10 and 9/10 ths of the width of the annulus, have a Y-, L-, T- or hook-shaped crosssection.