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Old 12-29-2018, 09:09 AM   #65
Delfin
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Quote:
Originally Posted by Steve DAntonio View Post
Delfin, I'm curious, are you conducting oil analysis? Some evidence suggests that certain additives can be removed by extreme filtration. For anyone who does oil analysis, whether or not bypass filtration is used, I recommend taking a reference sample, that is analyzing a sample of new, unused oil, to which later samples are compared. If additives were being removed, the reference sample would allow you to identify this.

An excerpt from an article on the subject, "The lubricant supplier said that additive suppliers indicate using filters down to a 3-micron size in hydraulic fluid
and wind turbine gear oil applications should remove particulates without leading to additive removal. But use of filters below 3 microns can cause problems. The lubricant supplier says, “We often hear that defoamers may be the first
additive to be removed from a lubricant if filters that are less
than 3 microns are used in a specific system.”

Another article on the subject https://www.machinerylubrication.com...tives-filtered

Probably more of an issue with splash lubrication, as in gearboxes, but still worth monitoring in crankcase oils that are uber-filtered.

It seems defoamants are the most vulnerable to extreme filtration.

For those who are interested, an article on oil analysis http://stevedmarineconsulting.com/wp...s143_Final.pdf
Very interesting Steve, I hadn't heard about potential issues with defoaming agents being filtered out. Assuming I am interpreting this correctly, in looking at the chart in the Machinery Lubrication article, it seems like it isn't a risk unless the viscosity of the oil is greater than something around 70 at 170 degree oil temperatures. That isn't going to happen, so it looks like the risk is pretty low. It also sounds like soot can reduce the effectiveness of the defoaming agents, which argues for better filtration, so I'm not sure how to sort that out.

And yes, I do oil analysis, and on the CAT with the bypass filter, Silicon at the last test was 1 ppm, which is what is used in the defoaming agents. I focus on elements contributing to wear, and for Silver, Aluminum, Chromium, Nickle, Vanadium and Titanium, there are 0 ppm of these elements at a 200 hour sample, so it seems to be working. Soot is 2 ppm, which I think is also low.
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