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LUBE-TIPS™
Lubrication Tips for Reliability Professionals     Jan. 23, 2002

This issue of Lube-Tips is being sent to 13,722 subscribers.

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What's the Best Test for Used Lubricants?

You've pulled the oil samples, labeled the bottles, boxed them
up and sent them off for testing. Play along with me now -
suppose your lab could only conduct one test. What would it be?

Tough call? Consider your options. If you've implemented a
rigorous proactive maintenance program, and keep your lubes
extremely clean and dry, you'd probably opt for a particle
count. Why should you choose the particle count?

The particle count is one of those catch-all tests. Almost
anything that goes wrong in the machine will result, sooner or
later, in increased particle counts. If misalignment, overloading,
water contamination, viscosity breakdown, or bearing failure
occurs, the particle count should rise.

If you've been trending particle counts on a clean system, you
have low background noise. This simply means that there isn't
a lot of contamination in the oil, so even a minor change
in particle contamination levels will be evident in the
particle count results.

Of course, I'd pick different tests for different environments
and applications. Some situations may call for wear debris,
water or other tests. Do you have a favorite test for your
applications? Send me an e-mail and let me know what test and
why. I'd like to hear your opinion.

Mike Ramsey
mramsey@noria.com

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BOOK BITS

From "Fluid Contamination Control" by Dr. E.C. Fitch:

"Water in tribological fluids (other than water-based fluids)
leads to a multitude of problems in terms of system damage and
failure. Perhaps the worst threat of water contamination in
storage is its reaction with additives and the damaging reaction
products.

"Moisture causes a filter-clogging slime to form in fluids
containing tricresyl phosphate (TCP), an antiwear additive used
in tribological fluids where an alkali is present. If ZDDP
(zinc dialkyl dithiophosphate) is used as the antiwear additive
instead of TCP, many deteriorating mechanisms could exist;
suffice to state here that ZDDP can decompose to form hydrogen
sulfide and, in the presence of moisture, transform into a
highly corrosive acid (sulfuric acid). Even in fluids of the
corrosion-prevention type, moisture causes an egg-white type
slime. According to T.N. Dean, when moisture is present,
corrosion-preventive additives can exhaust themselves by
"wrapping up" the moisture in additive and water dispersion."

For more information about "Fluid Contamination Control"
go to:

<http://www.noria.com/secure/product_detail.asp?catalogid=47>
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TODAY'S TIP

- To ensure that the correct lubricant is being used, try using
colored plastic grease caps. These fit right on the grease
fitting and also help keep dirt and/or water off the grease
fitting and hence out of the bearing. The color-coding can be
used for the type of grease or the frequency. They cost only a
few cents each. (Tip submitted by Ken Brown, Utility Service
Associates. Thanks Ken!)

Each tip published will earn the sender $25. To submit a tip
go to http://www.noria.com/question.asp

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Q & A

"What will cause zinc levels in my oil to fluctuate?"
Todd Machin, Power Resource Tech, Southern Minnesota Power

There are several reasons why zinc may be present in your oil
samples. These include wear of zinc containing alloys such as
brass, zinc plating and galvanized surfaces; also zinc-
containing additives, most notability zinc dialkyl dithiophos-
phate (ZDDP), a common antiwear and antioxidant additive.

The most common reason for fluctuating data is improper sampling.
Sampling accuracy dependents on sampling from the correct
location, using the same methods and procedures each and every
time. If you do not have a good handle on the correct procedure,
this would be the first place to start looking.

Other things that may impact zinc concentrations include the
addition of make-up oil (possibly the wrong oil), the method
used by the lab to analyze the sample (this is particularly true
if the data is being compared between different labs, that may
use different instruments) and changes in particle size, if the
source of the zinc is from active machine wear.

Mark Barnes, Noria Senior Consultant

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SUGGESTIONS, QUESTIONS AND TIP SUBMISSIONS
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Noria Corporation
1328 E. 43rd Court
Tulsa, OK 74105 USA
Phone: 918-749-1400
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