Fluidized bed apparatus

Claim 1

A fluidized bed apparatus for mixing, drying, granulating, pelleting, coating and/or sugar coating pulverulent or granular material, comprising: a receptacle which is at least approximately symmetrical about a receptacle axis, said receptacle having an interior adapted to contain said material with a lower portion having a downwardly decreasing diameter terminating in a lower edge; an immersion pipe which extends axially from above through the receptacle interior, the pipe having an exterior and upper and lower ends; gas outlet means communicating with the receptacle interior; means for connecting the upper end of said immersion pipe to a source of gas; and means for directing gas discharged from the lower end of said pipe upwardly into said receptacle interior, in an annular, substantially axial flow along the exterior of said immersion pipe, said means comprising a basin having a floor portion disposed below said lower end and a substantially cylindrical wall extending from the floor portion axially to the lower edge of the receptacle, said cylindrical wall being spaced radially outwardly of a lower portion of said immersion pipe and sized to define a narrow axially elongated annular space between said cylindrical wall and said immersion pipe communicating between said floor portion and said interior, said annular space having a height sufficient to direct gas exiting from said immersion pipe axially along the exterior of the pipe into the receptacle interior for fluidizing material contained therein and for entraining material substantially upwardly along the exterior of said immersion pipe.