Abstract: Gyratory and reciprocal motion classifiers for classifying particles in a fluidized particle bed according to size or density, and implementing a classification chamber for the fluidized particle bed and an activation chamber for enhancing the kinetic energy of particles prior to their introduction into the classification chamber. The activation chamber is movable with the classifier and preferably has a vertical thrusting surface and lateral surfaces convergent toward an exit opening which admits particles into the classification chamber in proximity to an upstanding surface for dispersing particles away from the point of entry and over and into the fluidized bed in a direction counter to the directional throw of the particle bed-supporting surface of the classification chamber.

Abstract: A particle separation method and apparatus carrying forward the teachings of U.S. Pat. No. 4,148,725 whereby separation of particles by density takes place in a size-classified fluidized bed of particles. Particles are disposed on a supporting surface having a plurality of generally concentric annular vertical reaction surfaces which together forms a plurality of annular channels occupied by the particles to be separated. The supporting surface and annular surfaces are agitated with a gyratory motion so as to induce particles in the fluidized bed to move within channels, and through openings between annular channels, toward a central collection zone.In the improved apparatus, the collection zone includes a plurality of vertically spaced horizontal reaction surfaces which enhance the fluidity of particles within that zone. A vertical barrier surface provides a smaller, annular zone of concentration at the center of the collection zone.