MP Filtri ACMU, User Manual

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Appendix A
Measuring Water Content 23
Measuring Water in Hydraulic
and Lubricating Fluids
From North Notts Fluid Power Centre
In mineral oils and non aqueous fire resistant fluids water is undesirable. Min-
eral oil usually has a water content of 50-300 ppm which it can support with-
out adverse consequences.
Once the water content exceeds about 500ppm the oil starts to appear hazy.
Above this level there is a danger of free water accumulating in the system in
areas of low flow. This can lead to corrosion and accelerated wear. Similarly,
fire resistant fluids have a natural water content which may be different to
mineral oils.
Saturation Levels
Since the effects of free (also emul-
sified) water is more harmful than
those of dissolved water, water lev-
els should remain well below the sat-
uration point. However, even water
in solution can cause damage and
therefore every reasonable effort should
be made to keep saturation levels as
low as possible. There is no such
thing as too little water. As a guide-
line, we recommend maintaining sat-
uration levels below 50% in all equip-
ment.
100%
75%
50%
0%
25%
Emulsified
Saturation point
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