Abstract: The present invention provides a reverse flow cyclone separator including a container closed at one end, a component for introducing a fluid mixture swirling about an-axis at a region of the container remote from said end, a barrier between said region and said end, the barrier having a surface facing the introducing component and extending towards the outer wall of the container leaving a gap therebetween, and an outlet for lighter phases of the mixture, the outlet opening from the region, the barrier having an outer perimeter which extends in the axial direction a distance not less than the radial extent of the gap. Since the outlet opens from the region, the flow of fluid from the fluid introducing component to the outlet is not obstructed by the barrier and does not pass through the gap.

Abstract: A cyclone separator has an inlet chamber 52 and an outlet chamber 53, means 51 for introducing a fluid mixture into the inlet chamber so that it swirls around the chamber and passes to the outlet chamber in which it swirls about an outlet chamber axis, the outlet chamber being provided with means 62 for conducting heavier phase fluids from the outlet chamber at a relatively large distance from the outlet chamber axis and an outlet 63 for lighter phase fluids at a relatively small distance from the outlet chamber axis 55. The flow through the separator and the efficiency of separation are improved by forming at least one of the chambers 52, 53 as involute shaped, the corresponding one 51, 62 of said means being defined by the curved wall of the involute of maximum radius.