Air
Air is used as the stratifying medium. Unless material is properly stratified initially, a good separation cannot be obtained. Too much air will cause a bubbling boiling action that remixes the material as fast as it is stratified. Too little air will not stratify the material properly. Generally, lots of air is required in the feed area to obtain good stratification. As material moves from feed end to the discharge end, progressively less air is required to maintain proper stratification.
Feed
Feed determines the capacity of the machine. Minimum feed is the lowest rate of feed at which an adequate cover can be maintained over the entire deck. Maximum feed is highest rate of feed at which an acceptable separation can be obtained. Between these limits, quality of separation generally goes down as capacity increased, and up as capacity is decreased.