Cyclonic separation is a method of removing particles from an air stream without having to use filters. The high speed rotating air-flow within a conical container creates high G-forces forcing particulate matter to the outside wall. As the rotating air-flow moves towards the narrow end of the conical container the G-forces steadily increase enabling the separation of finer particles.
Large scale cyclones are used among other things in saw mills to remove sawdust from extracted air and James Dyson employed this technique with his popular bagless dual and root cyclone vacuum cleaners.