Apparatus and method for treating an aggregate material with a flowing gas

摘要

Relatively coarse aggregate is preheated continuously and in a highly effective manner by directing the aggregate downwardly along a predetermined path of travel while maintaining the aggregate in the form of a relatively thin layer and while directing a flowing heated gas upwardly along a predetermined sinuous path of travel repeatedly passing laterally back and forth through the downwardly moving layer of aggregate from opposite sides thereof to thus provide highly effective contact of the gas with the aggregate. The thin layer of aggregate is guided downwardly along a passageway formed by a pair of gas permeable retaining walls which extend generally vertically in opposing spaced relation to one another. The retaining walls are of a nonlinear zigzag configuration so arranged as to direct the thin layer of aggregate along a sinuous path of travel in the course of its downward movement along the elongate passageway.