A solid or screen bowl decanting-type centrifuge comprising:a rotatable bowl; a helical scroll conveyor which rotates coaxially within the bowl at a different rotational speed, the helical scroll comprising a hub carrying a plurality of flights whose radially outer edges lie close to an inner wall of the bowl such that, in use, 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. The conveyor hub carries a plurality of nozzles in a wash zone for supplying wash fluid to solids being scrolled by the conveyer towards the solids discharge ports. The conveyor hub also carries a blade in the region of the nozzles and intermediate adjacent flights of the conveyor for directing fluid droplets from the nozzles over said solids.