Moisture content
Water can exist in oil in three states or phases.
- Dissolve Water
- emulsified water
- Free Water
Dissolve Water :- Dissolved water, is characterized by individual water molecules
dispersed throughout the oil. Dissolved water in a lubricating oil is comparable to moisture in
the air on a humid day - we know the water is there, but because it is
dispersed molecule-by-molecule, it is too small to see.
emulsified water.
:- Once the amount of
water has exceeded the maximum level for it to remain dissolved, the oil is
saturated. At this point, the water is suspended in the oil in microscopic
droplets known as an emulsion.
Free
Water :- free water
accumulates at the bottom of the lube system.
IMPACT OF WATER CONTAMINATION ON LUBRICANTS
•The
presence of water in a lubricating oil can cause the progress of oxidation to
increase tenfold, resulting in premature aging of the oil, particularly in the
presence of catalytic metals such as copper, lead and tin.
•In addition, certain
types of synthetic oils such as phosphate esters & dibasic esters are known to react with water, resulting in the destruction of
the base stock and the formation of acids.
•Additives such as sulfurous AW and EP type
additives and phenolic antioxidants are readily hydrolyzed by water, resulting in both additive mortality and the
formation of acidic by-products.
•Other additives such
as demulsifying agents, dispersants, detergents and rust inhibitors can be
washed away by excessive moisture. This results in sludge and sediment buildup, Filter plugging and
poor oil/water demulsibility.
Dissolved,
Emulsified, & Free Moisture Ranges in Oils
| Oil | Dissolved (ppm) | Emulsified (ppm) | Free (ppm) |
| New Hydraulic Fluid | 0-200 | 200-1000 | >1000 |
| Aged Hydraulic Fluid | 0-600 | 600-5000 | >5000 |
| New R&O Oil | 0-150 | 150-500 | >500 |
| Aged R&O Oil | 0-500 | 500-1000 | >1000 |
| New crankcase oil | 0-2000 | 2000-5000 | >5000 |
| Mineral Oil | 0-100 | 100-1000 | >1000 |
| Turbine Oil | 0-150 | 150-500 | >500 |
How to Measure Water
In Oil
1.Visual Crackle Test
2.FTIR
Analysis( Fourier Transform Infrared Spectroscopy)
3.Karl Fischer Moisture
4.Calcium Hydride
Test Kits
5.Saturation
Meters
6.Relative Humidity
Moisture Analyzer
 |
Crackle Test
|
 |
FTIR Analysis
|
 |
Karl Fischer Moisture
|
Mostly uses Karl Fischer for lub oil moisture Content
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