A hydraulic filter is the main component of the filtration system of a hydraulic, lubrication or greasing machine. These systems are used to control contamination by solid particles of external origin and those generated internally by wear or erosion processes of the machinery surfaces, thus preserving the useful life of both the equipment components and the hydraulic fluid.

The variety of filtration devices or filters is as extensive as the varieties of porous materials available as filter media and the particular conditions of each application.