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Contaminated Oil Testing

Contaminated Oil Testing

Contaminated Oil Testing

I am beginning to work on a new "contaminated oil" project. In short, we want to test our bearing's durability with differing amounts and sizes of hard particles in the oil supply (using ISO 4406 as an example: x 4-6 micron particles, y 6-14 micron particles, and z 14+ micron particles per mL of oil). Does anyone have suggestions about how to maintain a specified level of hard particles in the oil supply? We will be using a simple oil cart (reservoir, filter, pump) to circulate oil through our bearing system as it operates.

Problem #1: The filter is continually pulling particles out of the oil.
Problem #2: Our oil comes with many additives that are in the same size ranges that we are trying to measure. These particles may be the same size, however they definitely differ in hardness. Our particle counter will not be able to differentiate between the oil additives and the hard particles we introduce. Thus, it will be impossible to determine the true ratio of oil additives / hard particles even if we maintain a specified "count" of similarly sized particles suspended in our oil.


RE: Contaminated Oil Testing

Run without a filter element?
Then take samples over the run and determine how the count changes.
(does the bearing generate new particles itself? if a journal bearing, do they embed into the bearing?)

Jay Maechtlen

RE: Contaminated Oil Testing

Like Jay says. This seems so obvious it should not even need a mention.

Next obvious solution sans enough information that might contain a counter argument is to use a pure paraffin base oil with no additives and maybe extra distillation or exceptionally fine filtering process before use.

Of course you will still get debris from within the engine. Of course this can be minimised but not fully eliminated by very thorough cleaning before use.

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RE: Contaminated Oil Testing

Thanks for the input Pat and Jay. This is along the lines of what we were thinking. I appreciate your quick and thoughtful responses!

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