Has anyone heard of DC200 antifoam (silicone) causing significant particle count level increases as defined by NAS 1638 and using a Hiac automatic particle counter?
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Water dropplets and other dispersables will show up as "contaminants" in the fluid. Dust and dirt will also show positive for Si in the metals analysis. DC200 anti-foam will show possitive for Si as well. Parallel testing needs to be done to fully understand the contamination profile of a critical system. Historic trending analysis is your best bet.
Yes we have had problems with a silicone product in hydraulic oil. I do not remember what brand it was, but there where significant problems in automatic counts vs. microscopic. We got NAS10-12 in the automatic count, and NAS 4-5 in microscopic. Because of the difference we run an element analysis and found 50-70ppm of Si. The automatic particle counter (An advanced model) also took pictures of the particles over 20µm in size. They looked like half-moon shaped (not like cutting particles). Anyhow the excess of particles was found under 20µm in size. : -Therefor I recommend using a microscopic count (ARP598b or ISO4407).
