Hydraulic Filter ratings are an often misunderstood area of contamination control. On several recent occasions, I have witnessed someone describing a Hydraulic Filter Element by its nominal rating. A nominal rating is an arbitrary micrometer value given to the Hydraulic Filter by the manufacturer.
Hydraulic system designers go to great lengths to keep dirt and water out of hydraulic fluid — and rightly so. Water in oil-based hydraulic fluids can be just as destructive as particle contaminants. But Hydraulic Oil Filter Element Remove water vapour From oil?