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Small oil bath pump - metal particles in oil.

Small oil bath pump - metal particles in oil.

Small oil bath pump - metal particles in oil.

Hello group,

I am sorry if this kind of a utilitary question is out of topic for the group, but, working as a researcher in robotics (no, not walking iron men - rather electronic assembly ), I would appreciate an opinion on this compressor unit from a fellow engineer that that of a contractor from a forum at doityourself.com :)

I am purchasing a small (0.25 CFM is my lower requirement) air compressor and am currently evaluating a used unit, a few years old.  This is an oil-bath, very quiet unit handing on springs inside an enclosed thin-wall "pot".  It may be made by Jun-Air, and must be their type 3 if it is.  Rating is 0.9 CFM, 116 PSI.  Nothing looks wrong to me, it pumps a volume up to 100 psi in a time that matches a calculation.  However, when I opened the enclosure, the gasket between the cover and the body of the enclosure looked "sprinkled" with bright metal particles.  I took a few smears from its parts with a clean rug, and there were small particles (I cannot tell the size without a microscope, but they look uniform under a 10x loupe), order of hundreds in a sample from the area of units of cm^2.  The particles are magnetic; the color is bright white.  Their distribution seems uniform on all parts inside the enclosure, including top of the cover, so there seems to be no "hot spot" where a metal part would be being ground.

Oil itself is clean yellow color, transparent and smells of - well - synthetic oil, no "burnt" smell; the enclosure stays cold, in fact, even colder than I expected from a smooth unit witout any cooling fins.

Is this concentration of metal particles in oil acceptable for this type and size of unit and I can safely purchase it, change oil and have fun, or is this unit beyond help and is likely going to fail?

My practice with air pumps does not extend beyond operating their on/off switch, and this would appreciate very much an advice of the !

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