| 摘要 |
PROBLEM TO BE SOLVED: To improve the measuring accuracy or the sensitivity by accurately keeping constant the sample gas flow rate that is to be introduced into a detection section. SOLUTION: A flow rate resistance tube 7 is disposed on a detection flow channel 6 for introducing sample gas into a hydrogen flame ionization detector 10, and gas pressure in the flow channel on the upstream side is detected with a pressure sensor 8. A control section 9 converts the detected value of the pressure sensor 8 into a digital value, calculates the difference between the detected value and a control target value, delivers a control value from this difference, and changes the opening of a pressure control valve 5, thereby keeping constant the gas pressure in the flow channel on the upstream side of the flow rate resistance tube 7. COPYRIGHT: (C)2007,JPO&INPIT |
