Abstract
It is experimentally confirmed by the use of two small cylones and four kinds of test dusts the way in which the inserted length of exit pipe affects cyclone perfomances. When the inserted length is nearly zero, the collection efficiency remarkably deteriorates. But if the length is more than one fifth of the cyclone inlet height, the performance change is small. The pressure losses of cyclones only decrease slightly, even if the inserted lengths are zero.
However, the particle size distributions of emission dusts from cyclones approach those of feed (inlet) dusts as the inserted lengths decrease. For no inserted length, the both distributions coincide with each other, and no classification takes place in a cyclone.
