An air classifier for classifying a mixture of fine and coarse particles by size or aerodynamic shape, wherein the air classifier generally comprises a settling box through which a laminar airflow passes that improves introduction of particles into the airflow and thus improves separation and grading of particles by the air classifier.

A sieving apparatus for fractionating a grain product comprises a top chamber separated from a bottom chamber by a sieve; a top chamber cover defined by a plurality of openings that allow substantially vertical entry of an air stream into the top chamber when the interior of the sieving apparatus is under vacuum via first exit port in a side wall of the bottom chamber for exit of air; an inlet port in a sidewall of the top chamber, the inlet port configured for feeding of dry grain particles into the top chamber and for substantially horizontal entry of air into the top chamber; and a first exit port in a sidewall of the bottom chamber for exit of air and exit of a first grain fraction from the bottom chamber when the interior of the sieving apparatus is under vacuum via the exit port.

A rotating suction chamber apparatus for sorting a mixture of materials comprises a cylindrical drum with its upper end is at a higher elevation than its lower end. An upper housing connected to the upper end has a material intake for receiving the mixture of materials for introduction to the upper end. The mixture of materials includes a light fraction and a heavy fraction, and the upper housing has an outlet for the light fraction. A suction hood connected to the light fraction outlet includes a light separator shaft with a substantially vertical portion, and an air blower is adapted to create an airflow from the lower end, to the upper end, through the light fraction outlet and through the suction hood. A rotator rotates the drum about its longitudinal axis so that the heavy fraction is moved through the drum and falls out of the lower end.

A rotating suction chamber apparatus for sorting a mixture of materials comprises a cylindrical drum with its upper end is at a higher elevation than its lower end. An upper housing connected to the upper end has a material intake for receiving the mixture of materials for introduction to the upper end. The mixture of materials includes a light fraction and a heavy fraction, and the upper housing has an outlet for the light fraction. A suction hood connected to the light fraction outlet includes a light separator shaft with a substantially vertical portion, and an air blower is adapted to create an airflow from the lower end, to the upper end, through the light fraction outlet and through the suction hood. A rotator rotates the drum about its longitudinal axis so that the heavy fraction is moved through the drum and falls out of the lower end.

An air classifier for classifying a mixture of fine and coarse particles by size or aerodynamic shape, wherein the air classifier generally comprises a settling box through which a laminar airflow passes that improves introduction of particles into the airflow and thus improves separation and grading of particles by the air classifier.

An air-based particle filtration system (10) having at least one fan (26) to filter particles (especially coffee grinds) based on weight. The particle filtration system (10) includes a chamber (44) and a hopper (12) for dispersing particles to be sorted into the chamber. The particle filtration system (10) has a controller driving the one or more fans (26) and a collector (36) for conforming particles and optionally a discard collector (38) for non-conforming particles.