Abstract: A spray dryer consisting of a tower-like drying container with spraying elements for introducing therein the material to be dried, pipelines and heater for injecting a heated drying gas, and a separator for separating dry fine material and gas. The dry fine material is agglomerated inside the drying tower. The separator consists of porous filter tubes, on which a dust-laden gas stream impinges, which covers the entire flow cross-section of the drying tower. Fine product material deposited on the filter tubes is shaken off by surges of compressed air and drops into a drying zone, a spraying zone, and finally, into a collecting hopper.

Abstract: A method and apparatus for simultaneously washing a plurality of generally tubular or sock-like filtering elements of a gas filtering apparatus without removing the elements from the apparatus, the filter elements being disposed in a regular array of rows and columns within a housing between an inlet and an outlet thereof. The method includes positioning in the housing a liquid conduit having a plurality of axially spaced spray nozzles for delivering washing liquid along one or more rows of elements and supplying washing liquid to the conduit.