1995 Volume 21 Issue 1 Pages 56-65
Experimental and numerical studies were conducted on the classification characteristics of cage-type centrifugal powder classifiers by using three indexes : split ratio β to the coarser side of classified products; classification accuracy indexes κ1 (=d25/d75); and κ2 (=d50/d75).
β was expressed by an equation containing two parameters; β0 and γ, where, β0 relates to the aggregation index defined in this study, and γ relates to both the dissi-pation energy in a classifier and the 50% cut-size.
The index κ1 becomes smaller with decreasing dispersion efficiency in the classifier and the 50% cut-size.
As the rotational speed of the rotor should be increased in order to reduce the cut-size, air velocity passing through the adjacent rotor-blades would become uneven with a reflux of the air. As a result, large particles will mix into the finner powder, ie. κ2 will decrease. This phenomenon is suppressed by increasing the number of rotor-blades.
