| 摘要 |
PURPOSE:To discriminate the leakage from a piping and the deterioration of a vacuum pump by detecting the vacuum degree in a chamber at all times and judging the abnormality of the vacuum degree. CONSTITUTION:The vacuum degree in the chamber is detected at all times by a vacuum gage 16. The upper limit Vu and lower limit Vl of the vacuum degree in the chamber during the normal operation as well as the reference vacuum degree Vy when the supply of a measuring gas and ozone is stopped are then set in a vacuum degree setting part 22b. The vacuum degree in the chamber is compared with the set value of the vacuum degree setting part 22b in a relational judging part 22a. The clogging in the piping is detected when the vacuum degree during the operation increased to the upper limit Vu or above. A signal to close stop valves 18, 20 for checking when the vacuum degree during the operation decreases to the lower limit Vl or below. The leakage from the piping is announced upon increasing of the ultimate vacuum degree in the stage when the valves 18, 20 are closed to the reference vacuum degree Vy or above. The deterioration of the vacuum pump is announced when the ultimate vacuum degree is lower than the reference vacuum degree Vy. The abnormality relating to the pressure in the chamber is thus correctly detected and the quick dealing with such abnormality is made possible.
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