| 摘要 |
PROBLEM TO BE SOLVED: To allow continuous measurement for a long time, to make measuring ability hardly deteriorated caused by sucked dust, and to make concentration data accumulated over a long period together with time data. SOLUTION: A dust concentration is measured using an electric power source of AC 100 V in this unit 10. A casing 12 is provided with a cyclone 24 for introducing outside air by driving a suction pump 28 to classify the dust into coarse dust and respirable dust by a centrifugal effect, a measuring chamber 40 for measuring the classified dust by a light transmission system, a circulation pump 30 for circulating one portion of the air discharged from the measuring chamber 40 to the measuring chamber 40 again via a filter 34 to maintain an inside of the measuring chamber all the time by a sheath air effect, and a concentration display part 14 for displaying a measured dust concentration.
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