| 摘要 |
PURPOSE:To measure dust accurately by partitioning a dust densitometer into an upper and a lower casing, coupling them together by a coupling rod, and providing the upper casing with a projector, a photodetector, and a reflecting mirror and the lower casing with a reflecting mirror. CONSTITUTION:The reflecting mirror 3A provided to the lower casing 5 is irradiated with light from the projector 1 provided to the upper casing of the dust concentration meter. Its reflected light is reflected by the reflecting mirror 3B of the upper casing 4 and photodetected by the photodetector eventually. The projection light decreases in light intensity because of dust, so the dust concentration is detected. Further, the upper casing 4 and lower casing 5 are coupled together by the coupling rod 7 and the lower casing 5 is elevated to adjust optical path length. A calibration cylinder 10 is elevated with an elevation lever 11 to isolate a photometric part C from ambient smoke, and a zero point adjustment is made. Thus, the concentration meter is partitioned into the upper and lower casings and the smoke is isolated from external smoke, so the zero- point adjustment is made even in a smoke flowing state and the optical path length is adjusted according to the dust concentration, which is measured accu rately. |
