This is a continuously operating classifying device that utilises centrifugal force to accelerate the settling rate of particles . It is one of the most important devices in the minerals industry , its main use in minerals processing being as a classifier , which has proved extremely efficient at fine separation sizes. It is widely used in closed-circuit grinding operations (Napier-Munn et al,1996) but has found many other uses ,such as de-sliming, de-gritting,and thickening.