When water has entered an oil it is in a constant
search of a stable existence. Unlike the oil, the
water molecule is polar, which greatly limits its
ability to dissolve and may cling to certain metal
surfaces or even form a thin film around solid contaminants
such as silica particles. If increasing amounts
of water molecules are unable to find polar compounds
to attach themselves, the oil is said to be saturated.
With few exceptions, the chemical and physical
stability of lubricants are threatened by even the
slightest amount of suspended water. Water can promote
a host of chemical reactions that are unfriendly
to machinery. In combination with oxygen, heat,
and metal catalysts, water is known to promote the
oxidation and the formation of free radicals. Water
is also known to attack rust inhibitors, viscosity
improvers, and the oil's base stock. The effects
are undesirable by-products such as varnish, sludge,
organic and inorganic acids, surface deposits and
lubricant thickening. Large amounts of emulsified
water can lower viscosity, thereby reducing a lubricant's
load carrying ability. When water is combined with
metal catalysts such as iron or copper, accelerated
stressing of the oil can occur. This results in
base stock oxidation and the forming of free radicals
.
It is well-known that free water in lubricating
oil can decrease the life of rolling element bearings
by ten to more than a hundred times. The major bearing
manufacturers are all aware of this fact and it
is important that clients who use their bearings
are able to capture monitor small amounts of water
during online operation to avoid bearing embrittlement
and corrosion.
|
The EASZ-1 can detect a sudden increase
in water contamination in real time
Fig. 1.1 EESIFLO EASZ-1 Typical
installation on a hydraulic line |
