Particles of different sizes, shapes or specific gravities can be separated using the upward flow or air, also referred to as an elutriation. The AC series Aerodynamic Cyclonic air classifiers are based on this exact same principle. The process involves pneumatically conveying the powder to be classified into the classifier post which it is transferred into a fluidizing air stream.
The mixture is then introduced into the lower portion of the classifier whereas the upward flow carries the fine fraction of the powder removing it off the top of the classifier into a final collector. The coarse fraction of the powder is collected out of the bottom of the classifier using an optional airlock device or into a sealed container.
The amount of reverse flow, inlet air volume, collector type,size and the specific characteristics of the materials to be separated determines the degree of classification.