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Happy New Year!

Over the holidays I received several e-mails from Lube-Tips readers expressing their excitement about their lubrication program transformations.

One engineer at a paper mill was enthusiastic that they were able to get a budget approved to upgrade filtration equipment. Another reader started an oil analysis program five months ago and wanted to share a very impressive success story.

I've been fortunate to be on the receiving end of a lot these types of e-mails and it seems that lately they have been coming at a more rapid pace.

Why? Perhaps the economy - companies are trying to do more with less. Maybe it's just that we've got a bigger audience now - have you noticed that we passed the 13,000 subscriber mark over the holidays?

Anyway, we love hearing about what you are doing, and in 2002, one of our resolutions is to provide more useful information to help you achieve your goals for your lubrication and oil analysis programs. You are setting goals, aren't you?

Let us hear from you this year.

Mike Ramsey
mramsey@noria.com

Book Bits

From "Proactive Maintenance for Mechanical Systems" by Dr. E.C. Fitch:

A slight discoloration of the oil is nearly always present during the initial stages of oxidation. This discoloration increases as the process continues and the decoloration is accompanied by a drop in interfacial surface tension and a rise in viscosity, specific gravity and the neutralization number. The rise in viscosity and acidity are not necessarily inter- dependent.

Primary oxidation will cause a rise in acidity which will ultimately level off, at which point the viscosity may rise at an extremely rapid rate. Such increases in viscosity rate usually occur due to the generation of oxidation products of high molecular weight, held in fluid suspension. Paraffinic base oils are less apt to produce sludge at an earlier stage as those of a polynaphthenic base.

Click here for more information about "Proactive Maintenance for Mechanical Systems".

Today's Tip

• Excessive bearing vibration can have the same effect as irregular regreasing of bearing contact surfaces. It typically causes the grease to be broken down into the oil and the thickener, that is, the oil separates from the thickener.

  It is good practice to select greases which are suitable for vibratory conditions (your local lubricant supplier can advise you of suitable products) and to lubricate the bearings at short intervals--perhaps as frequently as weekly depending on bearing size, speed and operating conditions.

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Q & A

"We are experiencing sleeve bearing failures on a piece of equipment. The main cause of failure is bearing wear due to mechanical misapplication of the equipment. We are not in a position to change the bearing type yet because we have to meet current production demands. Would a simple magnetic plug help to remove 'free' particles of entrained bearing material and slow down the rate of wear until we can correct the root cause?" -- Jim Morcom

Unfortunately, magnetic plugs trap only large ferromagnetic wear debris (typically larger than 100 microns). Nonferrous particles associated with babbitt used in sleeve bearings would not be removed, nor would ferrous particles (shaft metal for instance) smaller than 100 microns.

Therefore, wear metal is unlikely to be trapped by a magnetic plug. I would suggest the following:

• Fitting a couple of quick connects to the bearing housing top and bottom would allow a small portable filtering unit to clean up the oil very rapidly. On the assumption that you would need to turn over the volume seven times, then a 5L/min pump would take less than 10 minutes to clean up the oil to a very clean level. In conjunction with the new breather unit, this would minimize the main cause of wear.

• Upgrade the breather/vent units if these are fitted. Bear in mind that a 10 micron particle entering through a vent plug is like a snooker/pool ball rolling through a doorway (there is little chance of stopping it.) A good breather will help ensure that no additional contamination is entering.

• If the machine is being stressed, oil temperatures are probably higher. The OEM specified oil may be too thin at the higher temperatures. Consider a change of lubricant viscosity specification, perhaps even to a multigrade or synthetic.

Martin Williamson, Noria Senior Technical Consultant

Copyright © 2002, Noria Corporation. All rights reserved. Please do not reprint or host on your website without explicit permission. However, if you found this newsletter helpful, we grant you permission, and strongly encourage you, to e-mail it to a business associate or a friend. Thank you. The presence of advertising in Lube-Tips does not constitute an endorsement of the products or services in such ads. Further, because results will vary widely based on a number of factors, Noria Corporation cannot warrant the results, the accuracy or the completeness of any material published herein.

Lube-Tips is published by Noria Corporation. Oil Analysis and Lubrication Experts