Two large hydraulic systems operated in a steel mill hall. At the first station, approximately 100 × 100 mm steel billets were straightened by a Rexroth hydraulic unit. At the second station, the billets were pre-ground to remove mill scale.
Grinding generated heavy airborne dust throughout the surrounding hall despite extraction. Under these harsh conditions, the hydraulic oil in both systems became severely contaminated. Even with well-sealed, regularly serviced breather filters on the tanks, the oil was heavily polluted after only two months.
When the straightening cylinders extended, the oil level in the tank fell and contaminated ambient air was drawn inside. Airborne particles entered the oil, forcing oil changes after only a few months. Valves and pumps also failed frequently.
The maintenance department tried several long-term improvements, including upgrading the extraction system to reduce dust in the hall.
Better breather filters were installed on the hydraulic tanks, and the cylinder seals were replaced regularly, but neither measure solved the problem. After reviewing filtration and oil-cleanliness options—and receiving positive feedback from other operators—the maintenance team decided to test a FRIESS EFR D8 electrostatic oil-cleaning system.
Before the EFR oil cleaner was started, an oil sample was taken from the system. A second sample was taken after 300 operating hours.
After cleaning, the oil condition had improved so significantly that it could be used again without restriction. The strong cleaning performance of the EFR system eliminated the regular oil changes previously required.
Hydraulic-oil service life increased from about two months to several years, while hydraulic-system failures fell by 70%.
For hydraulic-system operators: FRIESS also provides hydraulic-oil cleaning services; repairs and spare parts are not offered.
