You already know how dangerous cavitation and a "choking" pump can be for a hydraulic system. But before you start looking for complicated failures, it's worth looking at the very bottom of the oil tank. That's where an element that costs tens of zlotys is located, and its failure or clogging can destroy a pump worth thousands. BRhydraulic experts examine internal suction filters – especially the popular WU and JL/MF series.
1. Why is the suction filter (strainer) so important?
Before oil reaches the pump and is subjected to enormous operating pressure, it must be pre-cleaned. The suction filter, commonly called a "strainer", is completely immersed in oil inside the tank. Its main task is to capture the largest, most dangerous contaminants:
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Larger metal shavings from wearing cylinders.
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Pieces of decaying rubber detaching from the inside of old hoses.
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Small stones, rust, or even insects that may have entered the tank through a damaged filler cap.
2. WU series filters – classic and reliable protection
The WU series are among the most common suction filters on the market. What characterizes them?
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Mesh construction: The filtering element is usually a durable steel wire mesh (most often with an accuracy of 90-125 microns).
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Reusable: Thanks to the metal mesh, WU filters can usually be unscrewed, thoroughly cleaned (e.g., in extraction gasoline), blown with compressed air, and reinstalled.
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High flow rate: Their design offers minimal resistance to the sucked oil, which is crucial in preventing cavitation.
3. JL / MF series filters – compact precision
Filters with the designations JL and MF are a slightly different category of immersion "strainers," often used in more modern or demanding systems.
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They have a reinforced body construction, which prevents the filter from crushing (so-called implosion) if the oil is very thick and the pump generates powerful vacuum.
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They are available in variants with a denser pleated mesh, which increases their filtering surface while maintaining very small dimensions.
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They are most often mounted directly on the suction pipe using an integrated internal thread (BSP), which guarantees an absolute seal of the connection.
Summary
Replacing or cleaning the suction filter is an activity that many operators forget about for years (because "you can't see it"). A clogged WU or JL/MF filter guarantees cavitation, foamed oil, and the quick death of the pump.
Check your tank! If your "strainer" is bent, leaky, or clogged with dirt – don't risk it. In the BRhydraulic.eu store, you will find a full range of high-quality WU and JL/MF series suction filters with various connections and flow rates. Protect your pump today!