A direct-heat-stirred fluid bed dryer for fluidizing continuously changing portions
of a slurry or other moist product to be dried while stirring the product and applying sonic energy to the product for efficient dehydration.
This invention relates to a new and improved direct-heat-stirred fluid bed dryer for dehydrating a slurry or other moist product into a dried, granular or mealy form and for sterilizing the product.
Typical fluid bed dryers introduce drying gases into the drying tank or chamber through a porous or perforated grid and into the material to be dried in order to distribute the drying gases introduced under pressure to maintain a fluidized bed of the material. A problem with such conventional fluid bed dryer is that the temperature of the perforated grid or distributor plate through which the hot gases enter rises to a point at which slurry-type products stick to the grid or distributor plate.
It is an object of the present invention to provide a new and improved direct heat fluid bed dryer having lower effective wall and floor temperatures to thereby reduce the tendency of a slurry or moist product to stick to the floor and walls of the dryer and become overheated causing product damage and smoke nuisance. It is also an object of the invention to maintain a high rate of heat transfer by fluidization of slurry-type products to be dried without buildup of the dried product on the floor and inside surfaces of the dryer. Fluidization as used herein refers to suspension and agitation of material by a stream of gas.