A system for separating a heavy fraction from a liquid, including a housing and a mechanism in operative connection with the housing to induce rotational flow within an upper section of the housing. The system further includes a flow restrictor positioned below (that is, at the bottom of or below) the upper section of the housing in which rotational flow is induced by the rotational flow mechanism. The flow restrictor has a diameter less than the inner diameter of the housing so that a gap is formed between the flow restrictor and the housing. The housing further includes an inlet positioned above the flow restrictor and a first outlet positioned below the flow restrictor. The first outlet is positioned radially inward from an interior wall of the housing. The housing can be generally cylindrical from the top of the gap to a baffle positioned below the flow restrictor. The baffle defines a settling section for the heavier fraction. The housing further includes a second outlet in operative communication with the settling section. The system can further include a deflector positioned above the baffle and below the flow restrictor. The deflector has a diameter less than the diameter of the housing. The heavier fraction can, for example, include solid particles.