A centrifuge bowl for separating heavier particles from lighter particles and water comprises a conical lead-in wall leading of the bowl to a single recess or a pair of annular recesses at axially spaced positions. Each recess is generally V-shaped with an upper side wall, a lower side wall and a base. The base contains a plurality of angularly spaced valve controlled discharge ducts each having a mouth projecting through the base into the interior of the bowl for discharging the heavier particles in a continuous operation. The lead-in surface is stepped to cause tumbling of the flowing feed materials. The recess or recesses contain a concentrator ring which projects into the recess toward the base to reduce the amount of concentrate in the recess.