PURPOSE: To detect a specified gas with high accuracy, by providing a narrow band infrared filter transmitting substantially only absorption infrared rays of gas to be detected provided in a passing region of the infrared-rays which is incident to an infrared-ray detection and an intermission means for intermitting the infrared rays transmitting the filter.
CONSTITUTION: When gaseous CH4, CO, NO or NO2 leaks and fills the circumference of a gas sensor, an offset condition in the case of overlapping the second infrared nontransmitting bodies 25, 25Wwith the first infrared nontransmitting bodies 23, 23W, is broken because 3.3, 4.7, 5.3 or 6.2μm wavelength infrared rays are nearly absorbed by the gas, and the incident quantity of the infrared rays of an infrared-ray detection body 1 is altered. Also, in the case where the bodies 23, 23W oberlap with a P part of a narrow band infrared filter 19, the incident quantity of the infrared rays of the body 1 is the same as that existing at the time when gas leakage does not occur. Accordingly, a gas leakage detection is carried out continuously because the incident quantity of the infrared rays of the body 1 is altered periodically accompanied by periodical movement of the bodies 25, 25W during said occurrence of the gas leakage. Further, a detection signal outputted to a lead terminal 13 is sufficiently powerful and an S/N ratio is very good because the incident quantity of the infrared rays is largely altered suddenly.
NAKANO SHIYOUICHI
YOKOO TOSHIAKI
SHIBATA KENICHI
| JPS4952696A | 1974-05-22 | |||
| JPS5558438A | 1980-05-01 |