Q & A

"Is it alright to use grease rather than oil to lubricate plain bearings?"

While it is not always the best lubricant choice for a plain bearing, grease is suitable when:

• Speed is slow (below 400 rpm for a 2" bearing; below 50 rpm for an 80" bearing)

• Bearing is subjected to frequent starts, stops or shock-loading conditions

• Bearing is inaccessible for relubrication

Today's Tip

• Corrosive wear occurs when a machine surface is damaged by chemical attack. The responsible corrosive chemical could be either vaporous or liquid, which might be found in a plant that mixes or handles strong acid or alkali materials. Often the damage to lubricated surfaces come from acidic by-products generated by the deterioration of the lubricant itself.
  

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Book Bits

The vast majority of hydraulic systems in operation today have leaks; leaks that are planned. They are designed with a specific function in mind, and in many cases, are documented by the Original Equipment Manufacturer (OEM) as the amount of acceptable leakage under normal operating conditions. Internal planned leakage is typically small orifices or pathways that allow a lubricant from a higher pressurized side of a system to a lower pressurized area to lubricate, clean and cool a specific component or area. These planned internal leaks do not allow the lubricant to exit the hydraulic circuit so there is no visual indication of their presence.

This book bit was taken from the section "Detecting and Managing Hydraulic System Leakage" in the Practicing Oil Analysis 2000 Conference Proceedings.

For more information about the "Practicing Oil Analysis 2000 Conference Proceedings" go to:

http://www.noria.com/secure/product_detail.asp?catalogid=23

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