Dr method of operating a centrifuge filter

Abstract

A method of operating a drum centrifuge having a foraminous drum rotatable about an axis it is centered on comprises first filling a charge of a suspension into the drum while rotating it about its axis so that the charge forms an annular stratified body having an inner surface and the liquid phase of the body passes radially outward and leaves behind the solid phase as a filter cake and then refilling at least one additional charge of a suspension into the drum onto the filter cake while rotating the drum as in the preceding filling step to add the solid phase of the additional charge to the cake already in the drum. Then at least periodically the radial position of the inner surface of the body in the drum is detected and the dry point when the liquid phase has substantially passed radially out of the drum is ascertained to generate outputs corresponding to the detected radial positions and the times same are detected. The filter cake is then washed by passing a wash liquid therethrough for a time determined by the outputs and thereafter the washed filter cake is centrifuged for a time determined by the outputs.