Effect of Feed Rate and Classifier Height on Air Classification

The effects of varying the height and number of stages and feed rate for nonpulsing, passive‐pulsing, and active‐pulsing air classifiers is studied for the separation of complicated particle mixtures. All of the air classifier configurations tested achieve high $(>94\%)$ maximum separation efficiency. Increasing height is found to increase the range of air flow over which separation efficiencies greater than 90% are achieved. Decreasing feed rate has a similar effect. For each of the three classifiers studied—nonpulsing, passive pulsing, and active pulsing—the tallest classifiers at the lowest feed rates achieved the broadest efficient separation range. Results indicate that the passive‐pulsing air classifier performs better than the active‐pulsing air classifier, which in turn performs better than the nonpulsing air classifier.