In every hydraulic system, the cleanliness of the fluid determines efficiency, service life and operational reliability. Even before the oil enters the pump, the first line of defense against contamination comes into play: the suction filter. This filter component is positioned in such a way that it captures the entire oil flow in the suction path. This happens before abrasion, particles from repairs or external contamination can cause damage.
Whether in mobile machines, stationary systems or complex systems with hydrostatic drives: suction filters are key elements in fluid management. They make a significant contribution to avoiding cavitation, preventing failures and reducing operating costs in the long term.
What do suction filters do to protect a hydraulic pump?
Pumps perform a central function in the hydraulic system. They supply the entire system with energy by drawing in the fluid and pressurizing it. If contaminated oil gets into the suction path, there is a risk of serious consequences – from loss of performance and increased wear to total failure. This is precisely why the use of a high-performance suction filter is essential.
It prevents solids such as metal chips, plastic residue or seal abrasion from entering the pump. These can not only cause mechanical damage but also impair the function of downstream valves and other system components.
The filter also reduces the risk of cavitation. This is because even microscopically small particles or air pockets can lead to the formation of vapor bubbles when the flow rate changes rapidly. If these implode, pressure peaks occur that damage the surface of impellers and seals.
How can the maintenance effort for suction filters be minimized?
Suction filters work invisibly during normal operation. However, their condition determines the service life of the pump. We therefore recommend regular inspection and replacement of the suction filters with a sealing point to the environment after no more than 2000 operating hours or two years – whichever comes first.
For suction filters without a sealing point to the environment, cleaning is often sufficient by removing dirt from the outside with a paintbrush or soft scrubbing brush. It is important not to damage the structure of the fabric. After repeated cleaning (usually a maximum of two to three times), a screen filter should also be replaced so as not to impair the filter performance.
Maintenance is even more efficient with an integrated clogging indicator. It measures the pressure upstream of the filter element and gives a visual or electrical warning when the load limit is reached. This means that the change can be planned precisely – without unnecessary downtime, but also without the risk of reacting too late.
What role does the filter fineness play in the overall performance?
Not every system requires the same filtration performance. Depending on the pump, pressure level, tolerances and cleanliness class specifications, the filter element must be selected individually.
1.Screen filters made of stainless steel mesh (40 to 280 µm) offer basic protection against coarse particles and for robust systems.
2.Paper or non-woven filter elements (up to 16 µm) are suitable for demanding control circuits or high-pressure components.
3.Multi-layer media combinations are the first choice for high dirt absorption with low pressure losses.
The right fineness prevents abrasive particles from reaching the pump or proportional valves. It also reduces energy loss due to pressure drop and ensures a consistently stable oil quality during operation. However, filtration that is too fine can lead to high pressure loss. For this reason, each system must be individually adjusted.
