Patent ID: 7448992

Claim:
A solid or screen bowl decanting-type centrifuge comprising: a rotatable bowl for separating a slurry fed thereto into its constituent solids and liquid; a helical scroll conveyor which rotates coaxially within the bowl at a different rotational speed, the helical scroll conveyor comprising a conveyor hub carrying a plurality of flights whose radially outer edges lie close to an inner wall of the bowl such that, in use, separated solids are scrolled by the conveyer to solids discharge ports at one end of the bowl, with separated liquid being discharged from liquids discharge ports at the opposite end of the bowl; a plurality of nozzles carried by the conveyor hub in a wash zone for supplying wash fluid to solids being scrolled by the conveyer towards the solids discharge ports, the nozzles being arranged to produce respective mists of fine droplets of wash liquid which overlap to form a continuous fine spray of mist applied, in use, to the surface of said solids, wherein the wash zone is an open helical shaped wash zone free of any obstacles that interrupt the free flow of mist around the full wash zone; and at least one blade carried by the conveyor hub in the region of the nozzles and intermediate adjacent flights of the conveyor for directing fluid droplets from the nozzles over and through said solids, wherein the blade is shaped to follow a helix angle of the flights of the conveyor, the blade having a surface facing opposite and substantially parallel to a surface of an adjacent flight of the conveyor, with the plurality of nozzles fitted between the opposing substantially parallel surfaces of the blade and the adjacent flight of the conveyor.