We use Esso Nuto H Grade 46 oil in the motor bearings on our pulverizers. In the last two oil samples I took, one in October 2003 and one in January 2004, the copper levels had jumped from approximately 4ppm to 24ppm, reportable levels. This oil is sampled and changed on a ten week cycle. Can anyone give me insight as to the possible causes of an increase in copper? Thanks.

The source of cooper may be:
Reciprocating engine: bearings; wrist pin and valve train bushings; other bushings and thrust washers; oil cooler tubing;crossover contaminant from a leaking transmission seal.
Turbine engine: main and accessory bearing retainers; bushing and nuts; some oil control velves.
Transmission: Discs; bearings; bushings and thrust washers; oil cooler tubing.
Torque converter: Retainers and separators.
Differential: bearings, bushings; retainers, and thrust washers.
Hydraulic: bearings and bushings; swash plate cups; valves; some pistons; some pump cylinders; oil cooler tubing.
Compressors: bearings; bushings, thrust washers and retainers; oil cooler tubing.

Mikhail

Have you checked the particle count and the sample for wear debris,
a visual check with the microscope will confirm/deny any abnormal wear.

ISO 4406 particle count should be < 17/14,

We have noted a gradual change in copper in simular applications and in those instances the only copper in the system was the heat exchanger so we figure there is a tendency for the add package to chemically leach dissolved copper from the heat exchanger,

So do the same here, check out what parts in the pulverizers are copper containing then you will have an idea of what is occurring,
keep in mind you are only recording particles less than 8 µm with the ICP analysis and if you do not have a particle count you cannot predict failure in this type of application,
Regards Rob S

Rob,

How have you handled the leeching of the copper?

Do you consider it serious and have you changed oil specifications?

I have seen this before but have not been able to find resources to explain why it happens or what to do about it.

Thanks,

Ken G

quote:

---

Originally posted by rttech:
Have you checked the particle count and the sample for wear debris,
a visual check with the microscope will confirm/deny any abnormal wear.

ISO 4406 particle count should be < 17/14,

We have noted a gradual change in copper in simular applications and in those instances the only copper in the system was the heat exchanger so we figure there is a tendency for the add package to chemically leach dissolved copper from the heat exchanger,

So do the same here, check out what parts in the pulverizers are copper containing then you will have an idea of what is occurring,
keep in mind you are only recording particles less than 8 µm with the ICP analysis and if you do not have a particle count you cannot predict failure in this type of application,
Regards Rob S

---

I am agreeing with Rob S that in this case is (may be) excessive heat in heat exchanger that usually makes from copper alloys. Esso Nuto H oils derives its anti-wear properties from a zinc dialkyldithiophosphate (ZDDP) additive and at high temperature this additive can to reacts strongly with non-ferrous metals and alloys. It can result in increase Cu in oil bulk.

Mikhail

We have seen copper in oil caused by leaching from the heat exchager. It tends to increase slowly for a time and then increases rapidly. We watch the condition and replace oil when cu reaches about 80 - 100 ppm. We were told the heat exchanger would passivate at some point, but it hasn't for over five years.

Now we are tlaking my area of expertise. I have found correct product specifications matching with proper lubricants will save your butt. Call these guys 1-800-537-7683. We just had all of our pulverisers swithed to their 609 gear oil after 8 (EIGHT) years

chris nowlen

Hi Ken

this can be quantified by X the ppm of copper by the amount of litres in the system and this will give the amount of copper leached from what ever component is copper,
.
We have not had any component or fluid replacement because of this so far but we must add this test result is of interest and not that important when operating reduction drives as this figure only represents particles < 7-8 µm, reduction drives typically commence failure @ 100-300µm size particles meaning the ICP cannot detect large metallic wear debris, particle count is the only quantative way to monitor with the ICP identifying the possible source and the microscope verifying.

Rob S

quote:

---

Originally posted by QAken:
Rob,

How have you handled the leeching of the copper?

Do you consider it serious and have you changed oil specifications?

I have seen this before but have not been able to find resources to explain why it happens or what to do about it.

Thanks,

Ken G

quote:

---

Originally posted by rttech:
Have you checked the particle count and the sample for wear debris,
a visual check with the microscope will confirm/deny any abnormal wear.

ISO 4406 particle count should be < 17/14,

We have noted a gradual change in copper in simular applications and in those instances the only copper in the system was the heat exchanger so we figure there is a tendency for the add package to chemically leach dissolved copper from the heat exchanger,

So do the same here, check out what parts in the pulverizers are copper containing then you will have an idea of what is occurring,
keep in mind you are only recording particles less than 8 µm with the ICP analysis and if you do not have a particle count you cannot predict failure in this type of application,
Regards Rob S

---

---

rob pls call me for urgent talk

234-4815340 i need to discuss urgent

julius obaseki

PLEASE CONTACT ME FOR OIL DEAL ON NUMBER 234-1-4815340 JULIUS OBASELKI

I have seen this occur a couple of ways. Once with a slinger ring that was misaligned in its groove, a bad bearing cage was another. But the worst was due to an oil formulation change that was supposed to be benign. We had to change the oil type in our motors that had copper components. The rate of copper leaching never really changed either with an oil change or over time with out an oil change.

Hello rstock,
your message "We use Esso Nuto H Grade 46 oil in the motor bearings on our pulverizers. In the last two oil samples I took, one in October 2003 and one in January 2004, the copper levels had jumped from approximately 4ppm to 24ppm, reportable levels. This oil is sampled and changed on a ten week cycle. Can anyone give me insight as to the possible causes of an increase in copper? Thanks."
The easiest and most obvious answer is wear is taking place. Assuming that that meets with your acceptance the answer you should be looking for is what is causing the wear. So with that in mind try to answer some questions to narrow down the # of expiditions you will need to follow up on.
1) has the operational process changed -
more frequent starting and stopping
higher / lower operational temperatures etc
HIGHER THROUGH PUT - HIGHER AMP DRAW
2) recent maintenance work
replacement of the bearings
-could be seating issues
COMPONENT REPLACEMENT COULD HAVE CAUSED SOME ALIGNMENT ISSUES AND THUS INCREASSED WEAR

Your oil analysis results should be a compass to assist you in narrowing down the optons. If the only increase in any parameter is with copper then the issue is probably one of passification, or leaching as others have suggested. However if the lubricant type wasn't changed and the components wern't changed then this is less likely to be the case.
Now that you have our interest give us some more facts and we might be able to offer up some specific recommendations.
In the mean time contact the ESSO tech support and ask if there have been any recent formulation changes that might cause a chemical reaction.
Keep at it an answer will come....

regards......
alan

I have not read all the previous replies although it looked like the subject was covered well. One comment: copper is component of brass. Brass often found as slinger ring and cage. Trace amounts of zinc may tend to confirm the source is brass although I have often seen copper without zinc (don't know why).

Several replies have made some assumptions that probably need to be explored further. Does your motor have a circulating system with a cooler? Does your motor have sleeve (babbit) bearings? Have you checked the oil specifications for the motor? Our pulverizer motors have babbit bearings and do not have coolers. So lead would probably be the first element to show up in the case of bearing damage. If your motors have ball or roller bearings then you might have wear on a brass cage. All of our large, sleeve bearing motors have a turbine oil specified for the bearings and not a hydraulic oil. Isn't the NUTO line of oil a hydraulic oil with an anti-wear additive, probably ZDDP? The circulating systems on our pulverizers service the gearbox with an EP type gear oil. That kind of oil might cause trouble with the motor bearings, but the motors have their own oil for their bearings and use turbine oil.