Q & A

Be Careful With Brand Switching

“We recently installed a number of new vacuum pumps that were factory filled by the OEM with their own EP2 grease. Since we have a contract with a major oil company to supply all our oil and grease we want to use the same EP2 grease we use for other equipment in the mill. Is there any problem switching from the OEM EP2 grease to our lube suppliers product?”

Just like lubricating oils, extreme caution should be used when switching from one brand or type of grease to another. With greases, the major concern should be with the compatibility of the soap thickener used for each brand of grease. For example, certain types of greases that use calcium sulfonate soap thickeners should not be mixed with aluminum or polyurea based greases. Doing so can result in either a thickening or thinning of the soap medium, or separation of the base oil from the grease.

Unless you have strong evidence from either your lube supplier or equipment OEM that there are no compatibility issues between the two greases, you should treat them as if they are incompatible and thoroughly purge and clean the old grease from the pump before introducing the new product.

***Below is the corrected Q & A from the May 29 Lube-Tips which had the wrong question.***

Changing Oil Color

“We have a number of pumps located outside with automatic oilers attached. We have noticed that over a period of time the new oil changes color from almost clear to a light straw color. Can you explain why this might by happening to the oil and is it harmful to our pumps?”

Many oils when subject to sunlight will tend to change color slightly. This color change is simply a photocatalytic reaction between “natural” impurities in the oil and sunlight. In general, this change in color does not represent a significant chemical change to either the base oil or additives and should not pose a threat to the pump.

To confirm this, you may want to run some tests such as Acid Number (AN), RPVOT, or differential IR tests on both new oil from a barrel and the “sun aged” oil to confirm that there has been no significant change in base oil or additive chemistry.

Today's Tip

• Who is lubricating your machinery? When lubricants are accessible to practically anyone in a company, lubrication related problems are bound to develop. Inexperienced personnel could use improper lubricants and/or procedures or apply the lubricants at the wrong time, throwing off the lubrication schedule.
  

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Book Bits

Remember, over-packing probably accounts for more bearing failures than any other single factor. If too much grease is present, internal friction will cause the temperature to rise beyond its dropping point, causing oxidation of the grease and premature bearing failure.

For more information about "The Practical Handbook of Lubrication" go to:

http://www.noria.com/secure/product_detail.asp?catalogid=55

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