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In This Issue:

• Up Front: It Pays to Know Your Machinery

• Book Bits: The Proactive Maintenance Strategy

• Today's Tip: Don't Forget Barrier Fluids

• Q & A: Challenges with Food-Grade Lubricants

Up Front

It Pays to Know Your Machinery

This is a warning of a potential catastrophic failure of bearings due to the improper installation of minimess oil sampling valves.

I installed one on a 1500-hp electric motor with sleeve bearings that are lubricated by means of a slinger ring. The inward direct sample tube (pilot tube) came in contact with the slinger ring and would not allow it to turn and provide oil to the bearing. The bearing was destroyed in less than 10 minutes.

Knowledge of the slinger rings position and turning radius is crucial when installing these devices. I hope this will help prevent a similar failure elsewhere, as I believe the sampling devices are one of the best way to take oil samples.

Let us hear from you. Each Up Front story published will earn the sender $50. Submit a case study, experience or lesson learned. Or e-mail info@noria.com.

Book Bits

The Proactive Maintenance Strategy

From "Oil Analysis Basics".

While the benefits of detecting abnormal machine wear or an aging lubricant condition are important and frequently achieved, they should be regarded as low on the scale of importance compared to the more rewarding objective of failure avoidance.

Whenever a proactive maintenance strategy is applied, three steps are necessary to ensure that its benefits are achieved. Because proactive maintenance, by definition, involves continuous monitoring and controlling of machine failure root causes, the first step is to set a target, or standard, associated with each root cause. In oil analysis, root causes of greatest importance relate to fluid contamination (particles, moisture, heat, coolant, etc.) and additive degradation.

However, the process of defining precise and challenging targets (for example, high cleanliness) is only the first step. Control of the fluid's conditions within these targets must then be achieved and sustained. This is the second step toward proactive maintenance and often includes an audit of how fluids become contaminated and then systematically eliminating these entry points. Upgraded filtration and the use of separators are often required to meet proactive maintenance objectives.

More information about "Oil Analysis Basics".

Today's Tip

• One often overlooked lubricating fluid is the barrier fluid used in double mechanical seals. Though it gets topped off when the level in the seal pot gets low, how much thought goes into maintaining the high-quality lubricant needed for extended mechanical seal life?

  Seal faces are lapped to within two helium light bands of flatness and are every bit as precise of equipment as rolling element bearings. These lubricants are generally added to a seal pot and are expected to perform, essentially, for the life of the seal. Conditions to think about:

  • temperature, oxidation, coking of the lubricant

  • cleanliness

  • PM needs, scheduled changeout or sampling/testing

  • possible justification for synthetics

  (Submitted by Van Richard, Sr. Reliability Engineer, Georgia Gulf)

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Q & A

Challenges with Food Grade Lubricants

"My company uses a lot of food-grade oils and greases. Because the base oil in these lubricants is a white mineral oil, it is hard to see the level in the site glasses, especially when the oil is new. Our mechanics have asked, 'Why can't we add a food- grade coloring to the oil when we put it into the gear boxes and pumps so it's easier to see?'

My food-grade lubricant supplier has told me that adding anything to the oil, even another food- grade substance, will adulterate the food-grade quality. Personally, I am afraid anything we add could cause other problems, such as foaming or inhibit some of the qualities in the oil. Is there something that can be added to make the oil more visible to the eye and not hurt the application?"

I agree with the statement from your oil supplier, and your concerns on additive damage. I would not recommend adding any dye, colorant or aftermarket additives to an oil without approval from your lubricant supplier. Many lubricant suppliers have a list of approved dyes in nonfood-grade applications. Without their approval (in writing if possible), there clearly could be an impact on the legitimacy of the food-grade H1 rating.

However, like most puzzles and challenges, we sometimes miss the obvious! Consider adding a bright red float in your sight glass to make oil levels obvious.

Martin Williamson, Senior Technical Consultant, Noria UK Ltd.

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