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Copper content, dissolved or wear?

P peteMember
How can I tell if the copper content in in my samples is dissolved and wear generated? Patch test, Ferrogram? I don't have any good reference material on this subject.

Here is an example of what I an referring to. A vertical motor with a copper inner cooler in the upper bearing reservoir (25 gallon capacity). The cooler shows no sign of wear i.e. no sign of rubbing anywhere on it.

The sample valve and sample pipe are brass. I know, I know, not a best practice but, I have to fight one battle at a time. If I am lucky they might allow us to go to stainless sample lines. Mini-mess sampling would take an act of God to install at this time.
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K kimMember
We had the same problem with our condensate pumps, the ICP always indicated a high copper ppm. The ferrogram was always clean, we did an inspection durning an outage on one of the pumps, it was determined that the coolers were leaching off copper. A patch test or a ferrogram should give you the information you want. If the copper particles are large then they will be caught and you should be able to see them with a microscope.
J johnmMember
Pete, kim

With all do respect, it would be good to know the type of oil that you both are talking about. I am saying this because copper could be a metallic base for one or more of additives in your oil (check the baseline data for Cu level). In addition, AN should be checked (acids promote corrosion), and if possible conditions exist which would cause and promote electro-corrosion.
P peteMember
We just had the lab perform our routine test package on all the oils we use at the plant, for us to use as a baseline reference. The Cu baseline for this oil is <1.

Our TAN averages between .5 and .6, max. limit is .94. The oil is Chevron Machine Oil AW 150.

We think the Cu is leeching off of our inner cooler. We are going to have the lab run a patch test. Nothing showed up when we ran a Ferrogram.

Thanks for the input.
J johnmMember
Pete,

You are on the right track. Negative ferrogram clearly confirms that the copper is not present in your oil as a wear metal. Almost certainly it is there (as you suspected) as a result of the corrosion of inner coolers caused by relatively high AN. To confirm this theory, I would suggest that you ask your lab to run ASTM D 130, Standard Test Method for Detection of Copper Corrosion from Petroleum Products by Copper Strip Tarnish Test.

Although the article by Mr. Fitch is very educational and worth reading, it refers to engine oils which have high TBN, and almost never have AN as high as it is in your case.
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