FLUIDIZED BED COATING APPARATUS

摘要

A fluidized bed coating apparatus for coating liquid onto the surfaces of particles directed into a coating chamber. A liquid spray nozzle assembly disposed below a hollow separator within the coating chamber includes an ultrasonic atomizer for atomizing coating liquid into a fine liquid particle cloud and a pressurized air directing air cap for forming the ultrasonically atomized fine liquid particle cloud into a cone shaped spray pattern and propelling the liquid particles through the separator into an upbed region of the coating chamber for recirculation in an outbed region, and through the separator. A cooling air passageway system is provided within the spray nozzle assembly for cooing the ultrasonic atomizer during operation.

主权项

1. A fluidized bed coating apparatus for coating liquid onto the surfaces of particles comprising:
a vessel that defines a coating chamber for receiving particles to be coated; a processing air inlet for communicating processing air into an underside of said chamber; a liquid spray nozzle projecting upwardly toward said chamber from an underside thereof for spraying coating liquid upwardly into said chamber; a hollow separator disposed in upstanding relation relative to a discharge end of said spray nozzle into which a coating liquid sprayed from said spray nozzle is directed; said processing air inlet being operable for directing an upward air flow such that the particles to be coated are circulated upwardly through said separator to an upbed region of said coating chamber and then downwardly through an outbed region of the coating chamber outwardly of said separator for return into and through said separator; and said spray nozzle having an ultrasonic driver and a cannular atomizing stem extending from said driver, said stem terminating in a atomizing surface and having a coating liquid flow passage extending along an axis of the stem for directing liquid to said atomizing surface such that coating liquid directed through said liquid flow passage onto said atomizing surface is ultrasonically atomized into a fine liquid particle cloud for direction and passage through said separator into said upbed region of the coating chamber.