METHOD FOR CALIBRATING INFRARED MOISTURE METER

摘要

PURPOSE:To make possible the easy, stable and accurate calibration of a moisture meter by interposing a calibration chopper having a light attenuating filter and apertures on an optical path from a chopper having narrow band filters up to an object to be measured. CONSTITUTION:The calibration chopper 7 having the light attenuating filter 6 having the attenuation rate corresponding to the moisture value of the object 1 to be measured and the apertures 8 to allow the transmission of a reference wavelength band is pro vided on the optical path from the chopper 4 having the narrow band filter 5' which allows the selective transmission of the wavelength band (absorption wavelength band) to be absorbed in water molecules and the narrow band filter 5.. which allows the selective transmission of the wavelength band (reference wavelength band) not absorbed by the water molecules up to the object 1. IR rays radiated from a light source 2 are transmitted through the filter 6 of the chopper 7 when the absorption wavelength band is transmitted through the filter 5. The rays are transmitted through the aperture of the chopper 7 when the reference wavelength band is transmitted through the filter 6. The sample having 0% moisture value is thereupon irradiated and the light reflected from the sample is detected by an IR detector 11. The regulator for the moisture meter is adjusted in accordance with the detected IR quantity.