Method for automatic performance diagnosis and calibration of a photometric particle analyzer

Abstract

A method is provided for diagnosing the operation of a photometric particle analyzer. The method may determine when the operation is degraded from normal operating conditions, automatically, and the result displayed locally as well as being transmitted to a remote observer. The present invention may be used by optical photometric particle analyzers, or by analyzers that measure other properties of particles collected on filters.

1 . A method of testing a photometric particle analyzer, where the photometric particle analyzer includes a light source having light with a plurality of wavelengths, each with a controllable intensity, a filter to collect particles, a first light path from the light source through a filter that may be exposed to particle laden-air to a first sensor that produces a first signal, a second light path from the light source through a reference filter portion to a second sensor that produces a second signal, and a third light path from the light source to a third sensor without passing through a filter, where said third sensor produces a third signal, said method comprising:
 obtaining a baseline measurement of the first, second, and third signals, where said obtaining obtains with clean optics and filter within said first light path, second light path, and third light path, and where said obtaining includes:
 operating the light source at individual wavelengths of the plurality of wavelengths, and 
 recording the baseline measurement; 
   using the photometric particle analyzer to sample particle-laden air;   obtaining a test measurement of the first, second, and third signals for the photometric particle analyzer after using the photometric particle analyzer to sample particle-laden air by:
 replacing the collecting filter portion with a filter that has not been used to collect particles, 
 operating the light source at individual wavelengths of the plurality of wavelengths, and 
 recording the test measurement; and 
   generating an output from a comparison of said baseline measurement and said test measurement,   where said output is a diagnostic of the operation of the photometric particle analyzer.   
     
     
         2 - 24 . (canceled)