Damage Caused by Water and Air Contamination

The ingression of water or air into your fluid systems can cause significant problems. Problems include system corrosion, precipitates in the fluid, and foaming.

The major effects of water and air contamination:

  • Fluid breakdown, such as additive precipitation and oil oxidation
  • Detexiaration of fluid lubricating characteristics
  • Accelerated metal surface fatigue
  • Korrosion
  • Jamming of components due to ice crystals formed at low temperatures

Sources of water contamination:

  • Heat exchanger leaks
  • Seal leaks
  • Condensation of moisture in air
  • Inadequate reservoir vents
  • Contaminated servicing fluids

Forms of water in oil:

  • Free water (emulsified or in droplets)
  • Dissolved water (below saturation)

Water measurement techniques:

  • Crackle test (free water)
  • Centrifugal (free water)
  • Karl Fischer (free and dissolved water)
  • Distillation (free and dissolved water)
  • Capacitive Sensor (dissolved water)

Dissolved air and other gasses in oils cause:

  • Schaumbildung
  • Slow system response with erratic action
  • A reduction in system stiffness
  • Higher fluid temperatures
  • Pumpenschäden durch Kavitation
  • Inability to develop full system pressure
  • Acceleration of oil oxidation

Typical fluid saturation levels:

  • Hydraulic, Military
    200 - 800 ppm (.02 - .08%)
  • Hydraulic, Commercial
    1000 - 2000 ppm (.1 .2%)
  • Lubrication
    200 - 800 ppm (.02 - .08%)

Free and dissolved water cause component and fluid degradation. When fluid becomes cloudy in appearance, the saturation limit at the fluid temperature has been exceeded, indicating that both dissolved and free water are present.

Click on the links below to learn more:

Common methods for water removal
Effect of water on bearing fatigue life
Effect of water and metal particles on oil oxidation
Pump sensitivity to water

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