www.machinerylubrication.com
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May- June 2015
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reported in the technical data sheet of the
candidate oil. The higher the viscosity index
value, the less the viscosity changes with a
change in temperature. This is a crucial
factor to consider when looking to switch to
a different type or brand of oil.
Kinematic viscosity is the measurement
of a fl uid's resistance to fl ow due to the
effects of gravity. It is the viscosity that most
people are accustomed to in terms of how
thick a fl uid is. This will be one of the most
noted changes as the oil is heated, the
viscosity drops and the oil fl ows more
readily. For all tribosystems, the oil's ability
to fl ow and support loads is what protects
the component from surface degradation
and ultimately the loss of usefulness and
failure of the machine.
The viscosity at 100 degrees C is critical,
not just for vacuum pumps but for all
machines. It is important to understand the
viscosity requirements of the bearings or
gearsets at the operating temperatures and
to ensure that they are being met by the
lubricant in use. By verifying that the
viscosity is appropriate, you will be gener-
ating less wear and prolonging the life of
your machines.
If you have a question for one of Noria's experts,
email it to editor@noria.com.
