| 摘要 |
PURPOSE:To find the abnormality of pump in early stage by arranging a vacuum gauge for detecting the pressure in vacuum chamber and functioning an abnormality detecting means on the basis of a signal from said vacuum gauge upon droppage of the pressure in the vacuum chamber below setting level. CONSTITUTION:Upon driving of a vacuum pump 3 while closing a valve 4 coupled between a vacuum chamber 2 and a vacuum pump 3, the suction volume will be only that of the piping coupling between the valve 4 and the vacuum pump 3 thereby the vacuum pump 3 is immediately brought to no-load condition. Since an abnormality detecting means 9 coupled with a vacuum gauge 1 and the valve 4 will function on the signal from the vacuum gauge 1, the driving current produced from a driving current detecting means 8 is measured through said means 9 and compared with a proper level. If the driving current is higher than the proper level, abnormality in the vacuum pump 3 can be confirmed. Consequently, the abnormality of vacuum pump 3 can be found in early stage.
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