ical chemistry for the determination of the
amount of solid suspended in a liquid.
In micropatch analysis, the sample is drawn
through a 0.8-micron patch. A microscope is
then used to examine the patch and quantify
and qualify contamination and wear debris.
With analytical ferrog-
raphy, solid debris that is
suspended in a lubricant is
separated and deposited
onto a slide where a micro-
scope is used to determine
particle size, concentration,
composition, morphology
and surface condition.
A cheaper alternative
(although not as scientific or
valuable) is a sensory inspec-
tion of the "slime." How
does it look, feel and smell?
Sometimes these senses can
give a very good indication
as to what the problem is.
Visually inspect the oil for
a change in color. A color
change can indicate the
wrong or mixed oil, a
photo-catalytic reaction,
oxidation, thermal degrada-
tion, soot loading or
chemical contamination.
Look for any emulsions or cloudiness. Take
note of any free water that settles to the
bottom. Does the sample contain any sedi-
ment? If so, what color is it? How fast does it
settle? The answers to these questions can
provide clues as to what is ailing the oil.
How do the lubricant and "slime" feel?
Lubricants should be slippery, not clingy
(unless specially formulated with tackifying
agents). Greases should feel buttery, not
stringy or lumpy. If the "slime" is sludge forma-
tion, it will feel hard, pasty and sticky.
Lastly, how do the lubricant and "slime"
smell? Can a contaminant be identified? Lots
of contaminants have distinct smells,
including solvents, process chemicals,
hydrogen sulfide, etc. If the oil smells like
rotten eggs, the culprit may be oxidation. If it
smells like burnt oil, that's exactly what it is,
thermally degraded oil.
Sometimes the combination of these
sensory inspections can yield a diagnosis as to
what the problem is. Other times more infor-
mation is required and the sample must be
sent to a professional lab for analysis. Either
way, if the "slime" must be identified, it will
need to be interrogated.
If you have a question for one of Noria's experts, email
it to editor@noria.com.
September - October 2014
|
43
Stay Connected With noria
Follow us on Twitter
https://twitter.com/NoriaCorp
Like us on Facebook
http://www.facebook.com/noriacorp
Connect with us on LinkedIn
https://www.linkedin.com/company/
noria-corporation
Continue learning with us
on YouTube
http://www.youtube.com/user/noriacorp
Many oil analysis laboratories offer
filter debris analysis.
