PURPOSE: To enable accurate evaluation of purity continuously concerning a large-capacity object to be measured by comparing a class-wise frequency dis- tribution data previously prepared with a frequency distribution data from a statistics which is compiled covering counts of the number of particles per unit time in terms of unit capacity.
CONSTITUTION: Air 4 sampled from a room to be measured is run through a passage 3 at a constant speed and particles in the air 4 is irradiated with a beam 8 to detect a scattered light 9 generated with a photo sensor 11, where the detection frequency is counted with a counter 13 and fed to a frequency distribution data processor 14. The processor 14 also measures the number of particles per unit time sequentially and then, compiles a statistic in terms of unit capacity to prepare a frequency distribution data of counts. The comparator 18 compares the current frequency distribution data with a class-wise frequency distribution model applied from a model memory 19 and a class identical to or similar thereto is shown on a display unit 20 thereby enabling an accurate evaluation.
WAKIYAMA FUMITOSHI
TAKAHASHI KAZUHIKO
KOJIMA AKIRA
TAKEHANA YOUICHI
TANABE YOSHIKAZU
