Contaminated CNC coolant enters the hydrocyclone at high velocity through the inlet opening. Using a whirl chamber, the liquid swirls downward in the conical separate chamber, its velocity increases. Solid contaminants are thrown against the walls, forced to the bottom, and discharged through a nozzle. As the whirling cleaned liquid approaches the bottom, it is unable to exit the restricted discharge nozzle. It then reverses direction, forms an inner vortex and seeks the clean liquid outlet.