| 摘要 |
A method of continuously measuring the CO2 content in breathing gases during inspiration and exhalation phases of breathing using a luminous source to pass infrared light rays through an interference filter accorded to CO2 and a conduit of the gas to a photodetector, comprises passing the breathing gas developed during the breathing phases through the conduit to influence the photodetector to transmit a measured value signal in accordance with the CO2 content, directing the signal to a breathing air phase recognition unit, storing the maxima and the minima of the measured value signals in each breathing phase in a maximum storage and a minimum storage, dividing the stored values under the control of the recognition unit and directing the values to a computation unit to indicate the logarithm of the values so as to give an indication of the variations of the CO2 content. The indicated value is then directed to an indicating unit to show the value of the CO2. The apparatus includes a tubular cell or conduit comprising a measuring cell which is arranged centrally between a luminous source and an interference filter accorded to CO2 on one side and a photodetector on the other side thereof. A measuring cell tube is mounted on a stable support which is adapted to be warmed up during operation. The system includes a light modulator between the luminous source and the interference filter and a lens system for directing the light through the measuring cell and through the photodetector.
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