Abstract: A cyclonic device for separating entrained matter from a fluid stream under pressure includes a vortex chamber having a longitudinally upright cylindrical part and a subjacent frusto-conical part. Inlet and outlet means are provided for causing the fluid stream to flow first in a downward spiral and then along an ascending vortex. The entrained matter is separated from the fluid stream by centrifugal and inertial forces acting thereon from the swirling fluid flow. A cylindrical filter screen is provided concentrically disposed within the chamber and defines an area through the ascending vortex flows. The filter screen further separates relatively less dense matter from the fluid stream prior to the fluid flowing along the ascending vortex. A freely buoyant spherical ball is provided which acts as a check valve to close the chamber outlet means when a predetermined level of separated matter accumulates in the chamber.