CLASSIFICATION EFFICIENCY OF CAGE-TYPE AIR CLASSIFIER

Experimental and numerical studies were conducted on the classificatio n characteristics of the cage-type centrifugal powder classifiers by u sing three indexes: split ratio beta for the coarse fraction of the cl assified products. and classification accuracy indexes kappa(1) = (d(2 5)/d(50)) and kappa(2) = (d(50)/d(75)). beta was expressed by an exper imental equation, containing two parameters, beta(o) and gamma, where beta(o) related to the agglomeration index defined in this study, and gamma related to both the dissipation energy in a classifier and the 5 0% cut size. The index kappa(1), became smaller as the dispersion effi ciency of the classifer decreased or when, the 50% cut size was relati vely small. The velocity of the air passing through the adjacent rotor blades tended to become uneven with recirculation of the air, when th e rotational speed of the rotor was increased in order to reduce the c ut size. As a result, large par ticles tended to become mixed in the f iner powder and kappa(2) decreased. This phenomenon could be controlle d by increasing the number of rotor blades.