Contamination and Filter Selection 381

Contamination and Filter Selection describes common contaminants that may affect a fluid system. Contaminants include solid particles, liquids, and energy. Hydraulic and pneumatic systems are both subject to contamination, but hydraulic systems are more susceptible due to their higher operating pressures and recirculation of fluid. Filters are used in a fluid system to clean fluid and control contamination. Filters are selected based on the target cleanliness for a system or component. A knowledge of the filter selection process helps fluid system operators to determine the most efficient and appropriate filter to use. Being aware of common contaminants that may damage a fluid system helps machine operators prevent malfunctions and reduces downtime.