Hydraulic filters – protect your hydraulic system and its components against contamination.

The main function of a hydraulic filter is to remove contaminants and dirt particles from the hydraulic fluid. Since around 80% of all premature hydraulic system failures are caused by contaminated fluid, filtration protects pumps, valves, and other components from abrasive wear and damage. This extends the system’s service life, reduces downtime and repair costs, and ensures reliable, efficient, and long-lasting operation.

• Internal contamination: Caused by wear of components, rubber particles from hoses, or fluid degradation (often due to high temperatures).
• External contamination: Enters the system from outside, e.g. during assembly, through leaking tanks, or inadequate air filters. Breather filters are important to prevent particle ingress through the air.

• Surface filters: Thin mesh layers (metal, paper, plastic), often pleated for larger area. Particles are retained on the surface. Typical ratings: 25, 60, 90 µm.
• Depth filters: Fluid passes through a porous structure (cellulose, fiberglass, sintered metal). Particles are trapped within the depth layers. Microfiber media can filter down to 1 µm. Paper filters are a cost-effective option (10–25 µm).

• Return filters: Most common, often mounted directly on the tank. Advantages: cost-effective, easy to service, fine filtration. Disadvantages: contamination is captured only on return flow, bypass valve required.
• Suction filters: Located in the reservoir below the fluid level. Advantages: protect the pump from coarse contamination. Note: pumps are sensitive to vacuum, so large filter area and bypass are recommended.
• Pressure filters: Installed downstream of the pump in the pressure line. Advantages: protect sensitive components, very fine filtration possible. Disadvantages: more expensive, heavier, possible flow resistance generates heat.
• Breather filters: Mounted at the filler and breather port. Advantages: prevent contamination from entering through the air.

• Filter elements: Wire mesh, cellulose, fiberglass, sintered metal fiber, synthetic fiber media, paper, or microfiber. Microfiber allows very fine filtration (down to 1 µm).
• Filter housings: Made of steel, aluminum, or plastic – depending on pressure and temperature requirements.

Hydraulic filters are used wherever hydraulic systems are in operation:

• Agricultural and construction machinery (e.g. tractors, excavators, forklifts)
• Industrial equipment (e.g. presses, injection molding machines)
• Commercial vehicles and mobile machinery
• Vehicles (e.g. hydraulic steering systems)
• In all hydraulic systems for protection and reliable operation

• Regular filter replacement: according to service interval or at a defined pressure drop.
• Visual inspections: checking the filter and system condition.
• Clogging indicators: signal the optimal time for filter replacement.
• Bypass valves: ensure emergency operation if the filter is clogged.

• Filter type: suction, return, pressure, or breather filter depending on installation point.
• System pressure and temperature: housings and elements must withstand operating conditions.
• Filtration rating: 1–90 µm, depending on component sensitivity.
• Hydraulic fluid type and viscosity: materials must be compatible.
• Flow rate: filter must handle maximum system flow.
• Installation space & maintenance access: practical mounting and servicing should be considered.
• Application-specific requirements: depending on use (mobile hydraulics, industry).
• Features: clogging indicator and bypass valve recommended.