Fluidized bed dryer

Claim 1

Apparatus for drying particulate material comprising: a. a chamber; b. a gas permeable support at the lower portion of said chamber; c. a bed of inert thermally stable particles on said gas permeable support; d. means to introduce said particulate material to be dried into said bed; e. a screen located above said bed in a position to intercept and retain said bed of inert particles, said screen having a mesh small enough to prevent said inert particles from passing therethrough but large enough to allow dried particulate material to pass therethrough, and said screen being located from said bed a distance at least equal to the depth of said bed but not greater than six times its depth, whereby particulate material adhering to said inert particles or to said screen is dislodged therefrom upon the impingement of said inert particles with said screen. f. means to introduce a heated gas into said bed from beneath said support at a velocity sufficient to fluidize said inert particles and to blow dried pieces of said material through said screen; and g. means to collect said dried pieces.