Over 90% Less Contamination, ISO 16/14/11
After several weeks of EFR D8 cleaning, hydraulic oil in a wood-processing plant’s press improved from ISO 4406 class 23/22/19 to 16/14/11. Contamination fell by more than 90%, and silicon content decreased from 21 mg/kg to below 6 mg/kg. The cleaned used oil was cleaner than the fresh-oil sample tested alongside it, with additive balance and other values remaining within specification.
Case Background
The plant uses hydraulic systems to transport and clamp wooden components. High dust levels throughout the factory caused rapid contamination of the hydraulic oil.
Problem: Dust Ingress Exceeds Bypass Filtration Capacity
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. During operation, fluctuating reservoir levels repeatedly drew dust-laden air into the tanks through their air filters and expelled it again. The resulting contaminant ingress exceeded the cleaning capacity of the offline filtration unit.
Solution: FRIESS EFR D8 Electrostatic Oil Cleaning
To improve the oil condition and keep the hydraulic systems operating reliably, the company evaluated an alternative solution. After consulting the local representative of 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.
EFR Oil Cleaning Results
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, making the cleaned oil suitable for continued use.
Summary
- The electrostatically cleaned used oil was significantly cleaner than the fresh oil.
- Reservoir contamination fell by more than 90% compared with the condition before EFR cleaning.
- Silicon content decreased from 21 mg/kg to below 6 mg/kg.
- Additive balance and all other measured values remained within specification after cleaning.
- The cleaned hydraulic oil was suitable for continued use.
For hydraulic-system operators:
FRIESS also provides on-site hydraulic-oil analysis and purification services. Equipment repairs and spare-parts supply are not included.
Hydraulic-oil contamination causing valve wear or equipment faults in wood processing?
Please share your hydraulic-oil grade, reservoir volume, system pressure, ISO 4406 cleanliness level, particle and oxidation-product condition, fault symptoms and target values. Our China engineering team can recommend an EFR D8 configuration, bypass flow rate and operating cycle for your application.