| 摘要 |
<p>PURPOSE:To measure the concn. of carbon dioxide in a food pack using a very small amount of a sample, by irradiating a sample cell with light having a measuring wavelength and light having a comparing wavelength alternately, and detecting and amplifying the increase and decrease of transmitted lights to perform operational processing on the basis of the pressure variation of the sample cell. CONSTITUTION:When the gas sample collected from a food pack by a syringe 13 is injected in the injection orifice 10 of the syringe 13, the sample passes through a filter 9 to be guided to a pressure sensor 11 and a specimen cell 4 and the injected sample fills the sample cell to be discharged to the open air from a gas outlet 4b. Herein, an infrared ray source 1 alternately irradiates the ample cell 4 with infrared rays having a measuring wavelength showing the absorption characteristic of carbon dioxide and infrared rays having a comparing wavelength not absorbed by gas to be measured through a filter wheel 2 and a photodetector 5 detects the increase and decrease of transmitted lights to output the same to an operational processing part 7 through an amplifier 6 and the pressure sensor 11 senses pressure variation at this time to output the same to the processing part 7. The processing part 7 reads the output value of the amplifier 6 after about 1sec from the point of time when the signal of the sensor 11 returns to atmospheric pressure after once rises to output a carbon dioxide concn. value to a display output part 12.</p> |
