| 摘要 |
<p>PROBLEM TO BE SOLVED: To diagnose abnormality of a flow passage throttle nozzle and the piping system following the nozzle by reading in time dependency variation in the gas pressure value in an internal flow passage at self-diagnosis time associatively with the opening/closing operation of a closing valve and a flow rate control valve. SOLUTION: Before a slight self-diagnosis time before flow rate control starts, only the flow rate control valve 7 is opened while the closing valve 2v is closed to press reactive gas in the internal flow passage 4b, and then the flow rate control valve 7 is closed. Then only the closing valve 2v is opened and the time dependency variation in the gas pressure value P1 in the internal flow passage 4b is measured in the self-diagnosis time. When the flow passage throttle nozzle 25 is clogged, the lowering speed of initial pressure P0 becomes slow from the beginning of the self-diagnosis time. Thus, the clogging of the nozzle 25 is judged. When a shower plate 20a in a reactor 20 is clogged, the variation nearly equals a reference value from the self-diagnosis time to a sound velocity area, but becomes slow after the sound velocity area. Then the secondary-side flow passage following the nozzle 25 is diagnosed.</p> |
