| 摘要 |
PROBLEM TO BE SOLVED: To provide a device and a method for protecting a turbo molecular pump capable of taking countermeasures according to the kind of an abnormality when an abnormal situation occurs. SOLUTION: When an abnormal situation such as abrupt entry of the outside air into an inlet of the turbo molecular pump, the kind of the abnormal situation is estimated from the change of rate of the number of revolution of a rotor, etc., and the magnitude of the damage given to the turbo molecular pump by the abnormal situation is estimated from the number of revolution of the rotor when the abnormality occurs. In addition, a weighted value is corresponded to the magnitude of the damage, and the value is integrated every time when abnormality occurs in the turbo molecular pump. When the integrated value reaches a predetermined value, the turbo molecular pump is stopped, and protective functions such as prevention of re-start and alarm indication to an operator are actuated. |
