Patent ID: 7413084

Claim:
A substantially continuous method for separating particulate material based on particle size and/or density of the material, comprising: a) introducing a material comprising at least two solids having at least one of a distinct particle size and density into an inlet compartment; b) directing said material from said inlet compartment to a separation chamber having an interior surface and at least one opening on a face thereof, and an inner tube having an exterior surface, wherein an annular space is defined between the exterior surface of the inner tube and the interior surface of the separation chamber; c) providing at least a bottom portion of said separation chamber within a cavity of a rotatable compartment; d) maintaining a fluid within said cavity and above a bottom edge of said separation chamber; e) maintaining said separation chamber under a substantially negative pressure; f) separating said solids based on at least one of particle size and density of the solids by flowing said fluid in an upward direction through said material in said separation chamber at a predetermined velocity, wherein relatively larger and/or denser solids of said material are directed toward a bottom portion of said separation chamber and into said rotatable compartment, and wherein relatively smaller or less dense solids of said material are directed upward through said annular space of said separation chamber and out an outlet of said separation chamber; g) rotating said rotatable compartment so as to enable removal of the relatively larger or denser solids from said rotatable compartment; and h) directing said relatively smaller or less dense solids to an outlet of said separation chamber, wherein the predetermined velocity of the fluid is adjustable by varying a cross-sectional area of the annular space.