F26B 17/124

Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed solely by gravity {, i.e. the material moving through a substantially vertical drying enclosure, e.g. shaft the material moving through a cross-flow of drying gas; the drying enclosure, e.g. shaft, consisting of substantially vertical, perforated walls the vertical walls having the shape of at least two concentric cylinders with the material to be dried moving in-between}