| 摘要 |
An optical fluid analyzer uses the extent of optical, preferably infrared absorption of a fluid to be analyzed to determine the concentration of a selected constituant of the fluid. A first detector detects light after absorption by the fluid at a wavelength at which the selected constituant has a characteristic absorption for conversion into an electrical signal indicating the concentration of the selected constituant and a background from absorption of other constituants of the fluid for a measurement processing channel. A second detector correspondingly converts light after absorption by the fluid, but at a different wavelength at which the absorption at least approximates the background absorption alone for a neutral processing channel. The signals from the measurement and neutral processing channels are then subtracted to reduce the level of the background signal so that the level of the signal from the characteristic absorption can be more accurately processed to indicate the concentration of the selected constituant. The analyzer further has a first adjusting arrangement requiring ony a readily available, staple fluid to compensate for variations in the analyzer operation and a separate, second adjusting arrangement for presetting the analyzer with a standard fluid. Both the background subtraction and separate adjusting features of the analyzer particularly adapt it for analyzing liquid fluids. |
