LIGHT SOURCE UNIT FOR CO2 GAS CONCENTRATION VALUE SENSOR

摘要

PROBLEM TO BE SOLVED: To solve problems of CO2 gas concentration value sensors such as a failure to produce uniform gas concentration value sensors because of an indefinite optimum distance between an infrared ray sensor and a light source, and indefinite properties of a lamp used as the light source, thereby resulting in varying properties of the gas concentration value sensors, and a failure to enhance stability of the gas concentration value sensors because of an unknown measure of a light source unit case used for the CO2 gas concentration value sensors against a disturbance infrared light.;SOLUTION: A distance between the infrared sensor and the lamp is set to 40 to 50 mm, and a signal intensity ratio of a nitrogen gas to a carbon dioxide gas at 5,000 PPM is increased without greatly sacrificing a degradation of a signal intensity. Keeping a reduction ratio of a lamp current to a rated current of the lamp used as the light source at around 0.6, the signal intensity ratio of the nitrogen gas to the carbon dioxide gas at 5,000 PPM is increased without greatly sacrificing the degradation of the signal intensity. Furthermore, the light source unit case is covered with an aluminum foil sheet to reduce fluctuations of the CO2 gas concentration value sensor by the disturbance infrared light.;COPYRIGHT: (C)2010,JPO&INPIT