PRAB  candle filter is a one micron filtration unit with membrane wafers capture grinding swarf at 1 micron. A filtration specifically designed for most of the neat oil applications like tungsten carbide tool and cutter grinding, honing, and precision grinding applications.  These filters offer flow rates ranging from 13-80 gpm and can also be integrated with a chiller where temperature control is more important. The link will take you to the Prab press release.  How big is one micron? Human hair is about 50 micron.