Patent ID: 6695919
Filing Date: 2004-02-24
Classification: B01J,Y10S

Abstract:
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 generally cusp shaped ramp surface centrally positioned around said nozzle and directed upwardly towards said partition, said cusp shaped ramp surface being shaped to direct particles moving generally horizontally across said orifice plate from said down-bed upwardly into said partition and said up-bed.