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Water Awareness
Water Effect on System Fluids
"Water as a contaminant in the system fluid promotes oxidation and creates oxide particles, slimes and resins. Other more subtle effects also occur: conductivity increases, emulsions are created, and microbial growth is promoted. The combined effects result in the formation of a non-Newtonian fluid having thixotropic properties.
"Water often has a devastating effect on the additive package of a fluid. Water reacts with almost everything present:
* Oxidation inhibitors to form precipitates and acids
* Rust inhibitors to create deposits on internal surfaces
* Long chain molecules (for example, viscosity improvers) to form polymeric films and tribo-oxidation products
* Antiwear additives (ZDDP) to form hydrogen sulfide and sulfuric acid
* Long chain hydrocarbons that cause the solubilization of water to be strongly bound to long chain polymers in the reverse micelle, thus making it impossible to remove by drying. This solubilized water forms the basis of obliteration material which can plug and clog filters, orifices, and clearance spaces.
Water’s Effect on Systems
"The most prominent effect of water on fluid systems is simply corrosion and rust -- the action of both galvanic corrosion and acid corrosion. The underside of a reservoir top is a good place to see evidence of water damage.
"Water in fluid systems operating in the frigid north can cause frightening problems. Ice crystals can form as water is desorbed and droplets become entrained. The results upon circulation is jammed valves and clogged filters -- conditions that disappear when the fluid is warm.
"Reaction products with long chain polymers result in the formation of sticky substances. Such products clog fine filters, obliterate small orifices, and accelerate valve lock -- contaminant or silt lock.
"Since the vapor pressure of water is significantly higher than that of mineral oil and synthetic fluids, cavitation damage can occur. Water vaporizes at low pressure regions, and when the vapor bubble collapses next to a surface, fatigue damage occurs. Wire-drawing at orifices has been blamed on cavitation bubbles imploding as they pass the surfaces.
"Water in the fluid can have a pronounced effect on bearing life where rolling contact fatigue occurs:
* Hydrogen embrittlement of the bearing steel
* Increased cracks caused by fatigue because of superimposed corrosion effects.
* Reduces thickness of the lubricating film because of viscosity deterioration effects
* Corrosion from hydrogen sulfide and sulfuric acid"
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