| 摘要 |
PURPOSE:To enhance operability and maintenance, by automatically judging whether the abnormal value of light transmissivity being measured is the true value of a measuring medium or a value due to the abnormality of a light transmissivity meter itself. CONSTITUTION:Light transmitter-receivers 1, 7 for measuring the light transmissivity of exhaust gas 14 across a flue 13 are mounted on the wall of the flue 13. Operation is performed from the output voltages E1, E2 of photoelectric converters 6, 12 and voltages E1, E2' after attenuation using dividers 23, 26, a multiplier 27 and an extraction-of-square-root device 28 and the light transmissivity tau of the exhaust gas 14 is directly read by an indicator 29. By recording the alarm signal from an alarm output circuit 31 simultaneously with a transmissivity signal, at the time of abnormal recording, it is easily judged whether the concn. of the exhaust gas 14 is an abnormal value or a light transmissivity meter itself is abnormal. |
