Patent ID: 6363769
Filing Date: 2002-04-02
Classification: G01F,G01N

Abstract:
Method of determining instability in a personal air sampler comprising (i) averaging a series of at least four flows a, b, c, and d through said air sampler set at a desired flow rate and determining the total deviation of said four flows from the average thereof (ii) if said total deviation is higher than a predetermined maximum, causing an additional flow e through said air sampler set at said desired flow rate and determining the total deviation of said flows b, c, d, and e from the average thereof (iii) if said total deviation of said flows b, c, d, and e is higher than a predetermined maximum, causing an additional flow f through said air sampler set at said desired flow rate and determining the total deviation of said flows c, d, e, and f from the average thereof (iv) if said total deviation of said flows c, d, e, and f is higher than a predetermined maximum, causing an additional flow g through said air sampler set at said desired flow rate and determining the total deviation of said flows d, e, f, and g from the average thereof, whereby if said total deviation is greater than a desired maximum, said personal air sampler is determined to be unstable.