Several of our gearboxes supplied from the manufacturer have a breather that is basically a pipe plug with a hole drilled in it. Every once in a while, a less experienced craftsman rebuilds a gearbox and switches the drain plug with the breather plug. The result is always a messy oil leak.

On many gearboxes, we've started replacing these orifice breathers with particulate filter breathers. On gearboxes with the pipe plug breather, we've painted the breather plug a different color so it's easy to see. This helps ensure that the plugs are in the correct locations. (Bill Jacobyansky, Maintenance Manager, Guardian Industries)

Present your lubrication, oil analysis or contamination control-related case study at Lubrication Excellence 2008 in Nashville, Tennessee, May 20-22. Contact Leesa Lavern at llavern@noria.com or 918-749-1400 ext. 132.

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To those who are beginning the quest for knowledge in oil analysis and machinery lubrication, learning and comprehending terms, concepts and facts that seem like a foreign language can be a major obstacle. As an instructor, I'm always looking for new ways to introduce real-world analogies to help people understand these underlying concepts.

How to properly set and use particle count limits to effectively meet reliability objectives is a concept often misunderstood. Oil analysis users submit samples for particle count analysis each month; unfortunately, many have little idea what targets they should be aiming toward, and how to effectively use them. For a better understanding, consider fluid cleanliness in terms of driving a vehicle. Continue reading article.

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Question: Single-line parallel and single-line progressive are which category type of lubrication systems?

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"I have learned that high temperature encourages additive depletion and base stock oxidation in bearing oils. We are a paper mill and have been told by the paper machine supplier that our main lube oil reservoir should be maintained at 180 degrees F. Why are these high temperatures recommended, considering the harm it can cause?"

You are correct, high operating temperatures encourage additive and base oil failure. The widely used rule of thumb is that for every 18 degrees F increase in temperature, the life of the oil is cut in half. Still, it is common for high temperatures to be recommended in paper mill applications.

Reasons include better water-shedding ability, lower foaming tendency, better air release, improved particle settling rate, better drain back flows, and more rapid vaporization of water. However, most of the benefits from increased temperatures can be sufficiently achieved at, say, 140 degrees F.

At this lower temperature, viscosity will be higher and therefore you might want to revisit the viscosity grade selection. Lower viscosity oils, in general, are more resistant to oxidation and thermal failure. It is good advice to discuss a proposed temperature and/or viscosity change with your machine and oil suppliers.

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