This is how it works

The crankcase separator is built around a rotating conical disc stack. The crankcase ventilation gas is fed into the separator.

Oil and soot particles are removed from the blow-by by means of centrifugal forces of 2,500-3,000 G at a separator speed of 7,000-9,000 rpm.

The droplets and particles coalesce on the discs and form larger clusters which, due to the centrifugal force, move toward the outer edge of the discs, where they are discharged onto the inner wall of the separator housing. The droplets and particles then run down to the bottom of the separator, before finally being returned to the engine sump.

 

See how an Alfdex Oil Mist Separator works at https://www.alfdex.com/crankcase-ventilation/technology/