Is There Water In My Oil?

How to know if there is water in the hydraulic system?

  1. Creamy appearance of fluid in the sight level gauge
  2. Fluid seems to be growing in volume; fluid coming out of the filler/breather (a pretty sure sign the water/oil heat exchanger has failed)

Water in hydraulic fluid:

  • Depletes some additives and reacts with others to form corrosive by-products which attack some metals.
  • Reduces lubricant film-strength, which leaves critical  surfaces vulnerable to wear and corrosion.
  • Reduces filterability and clogs filters.
  • Reduces the oils ability to release air.
  • Increases the likelihood of cavitation occurring.

Methods for removing free (unstable suspension) and emulsified (stable suspension) water include:

  • polymeric filters
  • vacuum distillation
  • head space dehumidification

Vacuum distillation and head space dehumidification also remove dissolved water.

Polymeric Filters
Look like conventional filter elements, but the media is impregnated with a superabsorbent polymer (think baby diapers).  These are best suited for small amounts of water.  If a large amount of water has gotten into the reservoir; these would be used to do the final cleanup after a change and flush procedure.

Vacuum Distillation
Special equipment is used to apply heat and vacuum to the fluid. Not enough heat to damage the fluid. This method will also remove some oxidation residue.

Head Space Dehumidification
Use of a dehumidifier to circulate and dry the air in the space above the fluid level in the reservoir.

Prevention is the best cure. Use of a breather with a desiccant media to reduce ingression of moisture from the atmosphere will protect the system in high humidity environments.

In a system with highly sensitive components (think servo valves) use of a bladder to provide the level changes necessary (temperature, actuator actions) will prevent any air with moisture or other airborne contaminants from entering the reservoir.

Contact Kaman Fluid Power to speak with a hydraulic filter specialist today to learn more.

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Frank Stilwagner

Frank Stilwagner

Regional Sales Specialist at Kaman Fluid Power
With over 40 years of experience, Frank brings a great deal of understanding to the Kaman Fluid Power business. He has great knowledge in the fluid power, industrial distribution and pneumatics spaces.
Frank Stilwagner

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