We are interested in starting filter analysis on site for our filters that have been removed from a system. The problem is we can not find a set procedure to process the filter.

Some of the questions we have are:

How big a swatch do you analyze?
What solvent do you use to cut it?
What percentage do you cut it?
How do you prepare it? Cut it without creating more particles,
Is the area you analyze include the pleats or is it spread flat? More pleats more surface area.

We have the equipment to perform the test but, there seem to be varying opinions on the process.
Thanks for your input.

This message has been edited. Last edited by: Pete,

Filter analysis is used to get a look at the size and shape of particles and would be difficult to try and quantify wear amounts without some sophisticated machine that would measure the difference in total metal mass collected by a filter.

What you are looking for is the general shape and composition of the particles so the filter swatch size can vary. I have used cut outs that measure about 3x3 inches (flat) so it will fit into a standard 4 oz sample bottle.

I use straight lamp oil as a solvent and shake the samlpe vigorously for several minutes to dislodge as many particles from the filter media as possible. You then strain the lamp oil with the particles thru the patch maker.

BuckHntr,

Thanks for the input. Do you take the 3" X 3" cutout at the same location on the filter each time? Is it easy to tell the difference between the filter particles and any particles generated when you cut the filter?

Pete,

It all depends on what you want to find out. BuckHntr in his reply roughly described a simplified method of assessing the amount of wear, assuming that this is what you are trying to examine. However, there are numerous other goals that could be achieved and information collected, which would call for different extraction method(s). For example, one of many goals would be to brake down the accumulated sludge in order to find out how/why it is formed on the first place (chemical structure), and consequently, to figure out how to prevent its formation in the future. Another one would be to investigate reason(s) for filter clogging by identifying possible byproducts generated due to incompatibility of mixed lubricants, and so on and so forth. There are not many standard methods available, because there are no two lubricants that are the same (different additives packages, base oils). Some of the techniques, following the selective extractions, would require use of a scanner electronic microscope, GC, GCMS, ICP (combined with an acid digestion), XRF, laser particle counter, FTIR, ultracentrifuge, instruments and procedures for developing ferrograms, filtergrams (direct reading and/or analytical ferrography), identifying metallurgy, availability (and knowledge to use it) of wear debris atlas, etc., etc. It all depends on what you want to learn from analyzing debris from your filter.