Open air density separator and method

Abstract

A chamber has an aperture which opens downwardly to the atmosphere and an upwardly opening air return passage. A nozzle-forming duct is inclined upwardly at approximately sixty degrees to the horizontal, and a fan mounted therein directs moving air into the chamber. An upwardly inclined ramp is positioned within the duct, and communicates between the chamber and a downwardly opening hole in the floor of the duct. A metered supply of wood chips is fed down a sixty degree incline onto the ramp through the air stream which is moving through the duct. Lightweight chips become entrained in the air and are separated from the rocks, tramp metal and knots which slide down the inclined surface and exit through a hole in the duct. The entrained wood chips, together with the air from the fan, are directed into a curved baffle spaced within the chamber. By forcing the air and chips to move in a curved path, the curved baffle uses centrifugal force to separate the chips from the air stream. As the air stream expands into the chamber, its velocity drops then passes through the chip stream up to an air return. The chips, under the force of gravity, continue their downward flight, and exit the chamber through the bottom opening. An inclined ramp with a slowly moving conveyor may be used to avoid a build-up of material on the inclined ramp.