Patent ID: 8016117

Claim:
An air classification device for separation of solids comprising: an inlet through which the solids are provided to the air classification device; an air classification chamber in which the solids are separated into a first portion of solids and a second portion of solids based on a weight of the solids; a first air source for providing an upward-moving air stream through the air classification chamber to assist in the separation of the solids; a separator system through which at least a portion of the first portion of solids are discharged from the air classification device; a return line fluidly connected to the separator system for receipt of air discharged from the separator system therethrough; an outlet through which the second portion of solids are discharged from the air classification device; a first supplemental air line downstream of the separator system and in fluid communication with the return line; a second supplemental air line downstream of the separator system and in fluid communication with the return line; a first air knife fluidly connected to the first supplemental air line and positioned to present a high-velocity air stream into the inlet; and a second air knife fluidly connected to the second supplemental air line and positioned to present a high-velocity air stream into the outlet.