A decanter centrifuge includes a rotatable bowl extending along a centrifuge axis of rotation, and a rotatable scroll conveyor with hub mounted coaxially within the bowl. A feed pipe passes centrally within the hub and leads into a feed chamber within the hub. A plurality of circumferentially spaced apart nozzles extend radially outward from a round internal wall of the feed chamber to the outside surface of the hub and extend radially inward beyond the internal wall of the feed chamber. A plurality of discrete accelerator inserts are mounted on the internal wall of the feed chamber, wherein each insert is adjacently mounted between two nozzles and each nozzle is circumferentially fixed by abutment with the radially inward extensions of two of the spaced apart nozzles.