Abstract: Apparatus for use in, for example, separating oil from water, which comprises a vortex chamber adapted to admit through an inlet a flow of oil and water, means, (e.g. a helical coil shaped wall member of a “Clock Spring Guide”), device adapted to impart a rotational movement to the admitted oil and water so as to form within the chamber a rotating fluid mass within which a nonturbulent vortex of oil floats on the water. Oil removal pipe provides means for the removal of oil from the oil vortex, and outlet means located below the level of the floating oil provides for the escape of water from the vortex chamber. Variable flow regulating means is located at or downstream of the outlet means to regulate the rate of flow of water through the chamber. A tilted corrugated plate separator housed in chamber may be interposed between the water outlet means of the vortex chamber and the variable flow regulating means to separate residual oil in the emergent water.