A simple method for estimating cyclone efficiency is given based on th
e assumptions of a lognonnal size distribution and the generalized Lap
ple fraction efficiency curve. This method enables the prediction of t
he overall efficiency of the cyclone as a function of the cut diameter
of the cyclone, a parameter in the generalized Lapple distribution, a
nd the parameters of the lognormal distribution. The method shows the
most significant parameter in predicting the overall efficiency for a
lognormal dust is the ratio of the aerodynamic geometric mass mean dia
meter to the aerodynamic cut diameter.