Product category: Electrostatic Oil Cleaner

Electrostatic Oil Cleaner

Fast and reliably, Friess electrostatic oil cleaning systems remove dirt particles, oxidation products and other contaminants from non-conductive fluids such as hydraulic oils, transformer oils, turbine oils, lube oils and many others. The use of electrostatic oil cleaning removes particles down to less than 0.1 µm, as well as ageing phenomena such as varnish and oxidation products from the oil. Thus the service life and durability of the oil can be increased many times over. At the same time, machine precision is improved and hydraulic faults are significantly reduced.

Model D-1E
Oil cleaner for various oils containing up to 1% of water.
Model D
Oil cleaning units for various oils with a water content lower than 500 ppm.

This is how an electrostatic oil cleaner works:

The oil cleaning system is connected to the oil tank in a bypass flow. A gear pump is used to pump the oil from the reservoir into the electrostatic oil cleaning unit. Electrodes charged with 14,000 V high voltage are arranged in the cleaning chamber. The electrostatic field forces between the electrodes attract the contaminants contained in the oil and these deposit on the cleaning elements inserted between the electrodes.

This innovative operating principle not only removes hard contaminants such as metal particles, seal abrasion, chips, etc., but also removes soft contaminants such as oxidation products, varnish and sticky sludge particles from the oil. In addition, this operating principle is not dependent on pore size as is the case with conventional filters. The field forces act on all charged particles, regardless of their size. Thus, even extremely small particles and soft particles can be removed from the oil. The result is an extremely clean oil, with a better purity level than new oil. Through the permanent use of electrostatic oil purification systems, our customers have been able to avoid replacing their oil and only have to refill leakage losses, which significantly reduces the costs for oil.

Through consistent application of electrostatic oil cleaning, the service life of hydraulic oil can be increased to over 100,000 operating hours.


  • Up to 95 % reduction of oil consumption
  • Significantly lower costs for maintenance, repair and oil change
  • Up to 70 % less hydraulic disturbances
  • Increased process safety
  • Improved machine precision and control accuracy


  • hydraulic oils in injection moulding machines
  • Hydraulic oils in presses
  • Transformer oil
  • Turbine oil