Abstract: Fluidized bed apparatus, comprising a fluidized bed vessel in which a substantially horizontal rotor disc is arranged above a perforated bottom or above an air chamber for rotary movement about an at least approximately vertical axis and for adjustment along said axis. The fluidized bed vessel is tapered upwardly, one portion inwardly and one outwardly to enhance the flow therein and the rotor disc forms a flat cone and the disc may have a central cone with the rotor disc covering at least the central part of the perforated bottom.The questions raised in reexamination request No. 90/000,329, filed 02/15/83, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e).