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March - April 2020
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Oil mist is an aerosol
mixture of one part oil
to 200,000 parts air. It
is generated by passing
high-velocity air through
an orifice that pulls oil into the
air stream. e high-velocity air
stream breaks the oil into particle
sizes of 1 to 3 microns, thus the
resemblance to cigarette smoke
or steam. e same air, at a much
lower velocity and pressure, then
transports these small oil particles
through a distribution system to
the equipment to be lubricated.
ese small particles are referred
to as dry mist and are much too
small for lubricating purposes;
however, they are easily trans-
ported throughout distribution
systems over distances of 600 feet.
For lubricating bearings or
other equipment, dr y mist is
converted into wet mist prior to
the equipment being lubricated.
is is accomplished by passing
the dry mist through a reclassifier
(Figure 1). As these small particles
pass through the reclassifier orifice,
the increased turbulence causes the
particles to stick together and grow
in size. At this point, the oil mist is
referred to as wet mist. e larger
wet mist particles are now applied
to bearing surfaces and can lubricate
rolling-element bearings.
MAINTENANCE AND RELIABILITY
How Oil Mist Can Increase
Equipment Reliability
Marc Vila, Petronor
Wet Mist
Velocity and turbulence
convert dry mist to wet mist
Mist Flow
Dry Oil Mist
Figure 1. Oil mist reclassification.
Oil mist is
considered best
practice by the
hydrocarbon
processing
industry and is
recommended
within the
specifications
of the American
Petroleum
Institute."
"