particle counter

Dear Stewart2008,

Simple answer the calibration standard (ACFTD) ac fine test dust became not available.

We went looking for a substitute. We found one.

Having better technology we went back and checked the calibration of the old ACFTD with an electron microscope and found out the old dust we were calling 2 um was actually 4 um, and so on.

The new test dust is calibrated with the electron microscope.

The new calibration procedure is ISO 11171.

Purchase a copy and read to become wise. I'm not there yet.

Suggested Reading:

http://www.oilanalysis.com/article_detail.asp?articleid=409

http://www.techstreet.com/cgi-bin/detail?product_id=1032802

http://www.technologylubricants.com/Technical/NAS_Cleanliness_Classes.pdf

http://www.pall.com/pdf/POCKET_BOOK_EN_Standard.pdf

http://www.hydraulicparticlecounter.com/technicalstandards.htm

http://www.brookhaven.co.uk/products/zeta-potential/microspheres/standpcm.html

http://www.astm.org/Standards/D6786.htm

http://www.pmeasuring.com/support/papers/particlemonito...liquid/AP88/viewHtml

http://www.ngpharma.eu.com/currentissue/article.asp?art=273533&issue=251

Good Luck