In This Issue:

• Readers Challenge: Are You Testing Your Oil Onsite?

• Book Bits: Sorting Out Filter Types

• Today's Tip: Tags Clarify Valve Position

• Q & A: Time to Upgrade Your Grease?

Readers Challenge

Are You Testing Your Oil Onsite?

More than ever, companies are using onsite instruments and simple bench-level tests to get immediate information about the health of their lubricants and machinery.

From the simplest test (like the blotter test) to a full- fledged laboratory, most companies can benefit from screening and testing lubricants onsite.

Are you testing your own oil? Let us showcase your instrument, lab or test method in next week's Lube-Tips. Send us your digital photos and descriptions of how your company is using onsite oil analysis to prevent and predict machinery reliability problems.

To submit your company, e-mail up to three digital photos and descriptions of the photos to info@noria.com by noon Monday, March 11, 2003. Please do not send more than three photos. Lube-Tips editors will choose the best and most innovative response and the $50 winner will be announced and showcased next week.

Book Bits

Sorting Out Filter Types

From "Insider Secrets to Hydraulics"

Filters are commonly classified according to absolute or nominal ratings. A filter that is classified absolute has an efficiency of 98 percent or better at the specified micron size, and a filter that is classified nominal has an efficiency of between 50 percent and 95 percent at the specified micron size.

More information about the book "Insider Secrets to Hydraulics"

Today's Tip

• Consider installing plastic tags on all valves that reflect the normal status of the valve under operating conditions. For example: normally open or normally closed. This allows anyone to check the status for normal or clearance tags at a quick glance. (Submitted by Martin Bradley, mechanical constructor, Snohomish County PUD. Thanks Martin!)
  

Each tip published will earn the sender $50. Submit your tip.

Q & A

Time to Upgrade Your Grease?

"Our supplier recently informed us about a new low-noise grease manufacturing process for motor greases. This appears to be an exercise in repackaging a product to sell it under a different name at price premium. Does this new grease really offer extra value, or should I continue with what I am currently using?"

Low-noise level greases are those greases that have been purified sufficiently that there are no, or at least very few, large particles in the grease that could enter into the load zone and cause rotating elements to bump and grind, generating noise in the bearing.

These products were originally constructed for high-precision applications where the rise and fall of the bearing elements over contaminant particles entering the load zone through the grease could damage either the bearing or the driven component.

Let's take a look at a few issues surrounding this type of product. First, there are plenty of everyday applications where low-noise grease is highly desirable. The motors that control your stereo electronics, computer drives and other micro-motor applications would clearly benefit from low-noise or high- purity greases.

Second, bearing noise is eliminated by the removal of particles or contaminants that could cause the element to bump or impact the raceway. It makes sense that if there are contaminants that are large enough to interfere with the element's uniform movement through the load zone, that under the right loading conditions, the contaminants could possibly have some effect on bearing longevity and motor reliability.

This idea is consistent with the idea that particles in fluid systems can enter load zones and compromise load distributions, race and element surfaces and eventually component and machine lifecycles.

Also, there are several measures of grease quality. Grease cleanliness is characterized by the noise the grease produces in a bearing test cell. Standard off-the-shelf products are only visually checked for contaminants. The conscientious grease manufacturer would buy high-purity and high-quality materials from suppliers who demonstrate consistent quality.

However, without testing the raw materials and the final product for contaminants, it is impossible to determine just how much solid contaminant is in the final product.

There is a good argument that could be made for the use of low- noise grease in large grease lubricated industrial motors from a reliability perspective. It is likely that the improvement in motor bearing life would cover the cost differential on the premium for the low-noise grease product, assuming that the thickener, oil viscosity and other properties of the grease were acceptable.

For more information on this subject see the article:

Is it Time to Buy 'Quiet'? - Perfecting Grease Cleanliness

Mike Johnson, Director, Machinery Lubrication Technologies

Submit your question here.

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