| 摘要 |
<p>An absorption cell system for measuring and monitoring the concentration of specific gases in an ambient sample which includes at least one sample absorption cell into which there is introduced an ambient sample containing the specific gas to be monitored and a reference absorption cell into which there is introduced ambient sample from which the specific gas has been removed; a source of radiation of a wavelength absorbed by the specific gas being directed through the cell, the intensities of the radiation passing through the cells being separately detected, and subsequently compared and computed in a microcomputer which provides output data on the concentration of the specific gas in the ambient sample. In the system, the reference absorption cell is disposed in the path of radiation from the source in order that fluctuations in intensity of that radiation may be monitored in conjunction with absorption taking place in the sample cell. Also, to avoid errors arising from changes with time in the concentrations of gases other than the specific gas being monitored, the design of the device which removes the specific gas is optimized to synchronize measurements of the ambient and the ambient minus the specific gas. To increase frequency of measurements, a second sample absorption cell is incorporated in the system and operated 180.degree. out of-phase with the first sample absorption cell, necessary zeroing being done in one sample cell while measurements are made in the other.</p> |
