Overheating in Hydraulic Units? Selecting Oil Filter Elements by Accuracy & Pressure Drop

Hydraulic power units and injection molding machines run with high circulation flow and pressure. Customers often see fast clogging, frequent ΔP alarms, rising oil temperature, louder pumps, or unstable actuators. The root cause is usually wrong filtration grade vs. flow demand and low dirt-holding capacity.
Start by defining target oil cleanliness (ISO 4406). For general industrial HPUs, keeping oil at 18/16/13 or cleaner is common. Use 10–20 μm return-line elements with β≥200; if servo/proportional valves are present, upgrade return filtration to 10 μm with β≥1000.
Media choice matters: cellulose/paper elements soften and collapse at high ΔP or oil temperatures above ~80°C. Switch to multi-layer depth glass-fiber composites (coarse pre-layer + main filtration layer + support layer). This increases dirt-holding by 30–50% and stabilizes ΔP growth.
ΔP control extends service life. Install indicators or switches and replace elements around 0.25–0.35 MPa. A sudden ΔP spike suggests abnormal debris (machining chips, seal fragments, varnish). For 24/7 heavy duty systems, duplex housings allow changeover without shutdown. Finally, confirm the flow direction (inside-out or outside-in). Reversed installation can rupture media instantly.