US Patent 7763168 Control of centrifuges

A method of controlling a centrifuge of the type having a rotating perforated basket on whose inner peripheral wall a liquids/solids slurry is caused to collect in use, with separated liquid being collected via the basket perforations. The method comprising taking depth measurement of the material in the rotating basket continuous or at repeated intervals, over a basket cycle from commencement of slurry feed to discharge of solids, using at least one laser unit adapted to direct a beam of coherent light energy towards said inner peripheral wall of the basket of solids. The depth measurements can be made using at least one laser unit (30) adapted to direct a beam of coherent light energy towards said inner peripheral wall of the basket.