A large wood-processing company used several hydraulic systems to transport and clamp wooden components during production. Because dust levels were high throughout the plant, the hydraulic oil became contaminated very quickly.
The maintenance manager was dissatisfied with the cleaning performance of the existing hydraulic filters. To improve oil cleanliness and extend service life, a 5 µm bypass filtration unit was connected periodically to different hydraulic systems.
Despite high filter-element consumption, the overall cleaning result remained inadequate. Fluctuating reservoir levels repeatedly drew dust-laden air into the tanks through the breathers. The resulting contaminant ingress exceeded the cleaning capacity of the offline filtration unit.
To improve the oil condition and keep the hydraulic systems operating reliably, the company evaluated an alternative solution. After consulting FRIESS GmbH, maintenance personnel selected a D8 electrostatic oil cleaning system. Before connecting the FRIESS EFR oil cleaner, oil samples were taken regularly from the press hydraulic reservoir.
Condition before EFR cleaning:
Particle counts from December 2013 and October 2014 showed extremely high contamination. The ISO 4406 cleanliness class was 23/22/19—well above the level acceptable for a modern hydraulic system.
Silicon content was also excessive at 21 mg/kg and 39 mg/kg. All other values, including viscosity and additive balance, were within specification.
After several weeks of cleaning with the FRIESS EFR system, another reservoir sample was taken on 5 March 2015 and compared with fresh oil. The fresh oil from the drum had an ISO 4406 cleanliness class of 19/17/13, while the electrostatically cleaned oil in the press was significantly cleaner at 16/14/11.
Compared with the condition before cleaning, contamination in the reservoir fell by more than 90%. Silicon content decreased from 21 mg/kg to below 6 mg/kg. The additive balance and all other measured values remained within specification, allowing the cleaned oil to be reused without restriction.
For hydraulic-system operators:
FRIESS also provides on-site hydraulic-oil analysis and purification services. Equipment repairs and spare-parts supply are not included.
