Hydraulic filters are used anywhere in a hydraulic system to prevent particle contamination which is the main cause of hydraulic component failure. Hydraulic filters are used in three key locations of a hydraulic system, depending on the required degree of fluid cleanliness.

Importance of Hydraulic Filters in a System

Modern hydraulic systems run at increasingly high pressures and faster cycle times; as both of these attributes increase, so too does the system’s sensitivity to contamination. Fluid contaminants are a leading cause of hydraulic system failure and can cause numerous problems, including:

  • Mixing of unintended incompatible fluids, causing fluid breakdown and leading to acid corrosion.
  • Internal leakage, lowering component (pump, motor, valve) efficiency and accuracy.
  • Particle buildup in critical areas, leading to sludge which causes parts to stick.
  • Particle buildup in close-tolerance areas, leading to component seizure.

The obvious solution to preventing these problems is to prevent contaminant particles from cycling through the system. Therefore a clean, efficient filter is absolutely critical to a hydraulic system.


Hydraulic filters are often classified by where they are designed to be placed in a hydraulic system.

In-line, Off-line, Tank, Split-On, Return Line, Duplex

Filter elements are used to remove impurities from liquids. They are used in water treatment systems and fluid processing applications. Filter elements differ by type, and use either organic or synthetic filtration media. When selecting a filter element, must consider the relationship between particle sizes and levels of filtration. In addition to filtration grade, key performance specifications include maximum liquid flow and maximum pressure.

  • Micro filtration elements have membranes with pore sizes ranging from 0.1 to 10 µm.
  • Ultra filtration elements are designed to remove particulates between 0.001 and 0.1 µm.
  • Nano filtration elements separate molecules by size and are often used to purify, soften, and de-color drinking water.
  • Reverse osmosis filter elements use synthetic membranes that are permeable to water molecules and impermeable to contaminants.
  • Cartridge filters feature a pleated or mesh-like construction and may be disposable or recyclable.
  • Bag filter or bag house elements are used in a variety of processing applications. They provide a low-cost alternative to liquid filter elements such as filter cartridges.