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Arctic Conditions:
Arctic conditions represent a specialized field where exten-
sive use is made of heating equipment before starting. If
necessary, this, and judicious use of SAE 5W or SAE 5W-20
oil in line with the viscosity guidelines shown in the table,
may be used. Dilution of SAE 10W (MS) oil with maximum of
20% by volume of kerosene or low temperature diesel fuel is
permissible. During cold start-up, avoid high speed operation
of hydraulic system components until the system is warmed
up to provide adequate lubrication. Operating temperature
should be closely monitored to avoid exceeding a tempera-
ture of 130
°
F with any of these light weight or diluted oils.
Other Factors in Selecting an Oil are:
1.
Viscosity
- Viscosity is the measure of fluidity. In
addition to dynamic lubricating properties, oil must have suf-
ficient body to provide adequate sealing effect between
working parts of pumps, valves, cylinders and motors, but
not enough to cause pump cavitation or sluggish valve ac-
tion. Optimum operating viscosity of the oil should be be-
tween 80 SSU and 180 SSU. During sustained high temper-
ature operation viscosity should not fall below 60 SSU.
2.
Viscosity Index
- Viscosity index reflects the way
viscosity changes with temperature. The smaller the viscos-
ity change the higher the viscosity index. The viscosity index
of hydraulic system oil should not be less than 90. Multiple
viscosity oils, such as SAE 10W-30, incorporate additives to
improve viscosity index (polymer thickened). Oils of this type
generally exhibit both temporary and permanent decrease in
viscosity due to the oil shear encountered in the operating
hydraulic system. Accordingly, when such oils are selected,
it is desirable to use those with high shear stability to insure
that viscosity remains within recommended limits.
3.
Additives
- Research has developed a number of
additive agents which materially improve various characteris-
tics of oil for hydraulic systems. These additives are selected
to reduce wear, increase chemical stability, inhibit corrosion
and depress the pour point. The most desirable oils for hy-
draulic service contain higher amounts of antiwear com-
pounding.
Special Requirements:
Where special considerations indicate a need to depart from
the recommended oils or operating conditions, see your
sales representative.
Cleanliness:
Thorough precautions should always be observed to insure
that the hydraulic system is clean:
1. Clean (flush) entire system to remove paint, metal
chips, welding shot, etc.
2. Filter each change of oil to prevent introduction of
contaminant into the system.
3. Provide continuous oil filtration to remove sludge and
products of wear and corrosion generated during the life of
the system.
4. Provide continuous protection of system from entry of
airborne contamination.
5. During usage, proper oil filling and servicing of filters,
breathers, reservoirs, etc., cannot be over-emphasized.
