| 摘要 |
PROBLEM TO BE SOLVED: To provide a photoionization detector (PID) capable of simultaneously carrying out measurement and self-cleaning. SOLUTION: This photoionization detector PID has a microprocessor (MP), a first gas detecting unit (DUI), and a second gas detecting unit (DU2). The MP controls the DU1 and the DU2, and it always streams environmental gas (EG) through one ionization chamber (ICh) and detains the EG in the ICh of the other DU. A UV lamp (UV) converts oxygen in the EG to ozone, and it removes contaminated substances in the ICh. When the PID has only one DU, the MP controls the DU, and intermittently interrupts the flow of the EG of the ICh. As for measurement of real time self-cleaning and concentration of volatile gas (VG) by the PID, the PID measures the concentration of the VG by streaming the EG through the ICh of the DU1, and the EG passing through the ICh of the DU2 is hermetically sealed in the inside to be used for self- cleaning. The UV converts oxygen contained in the EG in the ICh of the DU2 to ozone, and removes contaminated substances in the ICh of the DU2.
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