Patent ID: 6911087

Claim:
An improved Wurster-type fluidized bed apparatus for applying a coating liquid onto the surface of particles, said apparatus being of the type including a vertically disposed cylindrical product container having a peripheral wall, at least one cylindrical partition defining a centrally located up bed region and a peripherally located down bed region, said product container further including an upper end connected to an expansion chamber, a lower end including an orifice plate having a plurality of openings for passage of fluidized air, a nozzle centrally located through said orifice plate and being adapted to generate a spray of said coating liquid upwardly into said up bed, wherein said particles located within said product container circulate upwardly through said partition and said spray of coating liquid, between said up bed and said down bed, said improvement comprising: a discharge opening located within said orifice plate, said discharge opening including a conduit positioned below said orifice plate, said discharge opening and said conduit being sized and shaped to permit material to be discharged from said product container; and at least one discharge jet positioned within said product container, said at least one discharge jet connected to a source of fluid and being positioned so that said fluid discharged by said at least one discharge jet is directed towards said discharge opening to urge said material located between said at least one discharge jet and said discharge opening towards said discharge opening to remove the material from the product container.