Treating fluidized material

A fluid bed apparatus for controlled residence treating of particulate material comprising

• means defining an enclosed treating chamber;
• a foraminous support extending longitudinally within said chamber for supporting a bed of material within the chamber, said support having an exit end;
• gas supply means beneath said foraminous support;
• means for supplying gas to said gas supply means under sufficient pressure to levitate the material in said bed and to form a fluidized bed;
• a series of spaced-apart flight means substantially coextensive with the fluidized bed movable longitudinally above said foraminous support past the exit end of said support, the lower edges of said flight means being substantially contiguous with the foraminous support and the upper edges of the flight means being no lower than the bed upper surface, thereby moving the entire bed of said material confined by the flight means longitudinally and uniformly along said support to control the residence time of the particulate material in said chamber, said flight means being independent of the support.