Aeration separator

An aeration separator for separating lighter and heavier particles comprising a separation chamber having lower and upper regions and upstream and downstream ends, the lower region accomodating the flow by gravity of heavier particles and the upper region accomodating the flow of airborne lighter particles, an inlet at the upstream end for the particles to be separated, a discharge from the upper region at the downstream end for the lighter particles, a discharge from the lower region at the downstream end for the heavier particles, a downwardly sloping passage in the lower region of the separation chamber, an upper wall defining the chamber and a flow passage in the upper region of the chamber for the flow of the airborne lighter particles toward the discharge from the upper region, an air source for introducing air into the lower region of the separation chamber for upward flow through the particles in the downwardly sloping passage in the lower region of the separation chamber to separate the lighter particles and direct them to the discharge from the upper region as the heavier particles flow through the downwardly sloping passage to the discharge from the lower region, and an air vent communicating with the upper region of the separation chamber through said upper wall to vent air from the chamber.