| 摘要 |
PROBLEM TO BE SOLVED: To provide an evacuation apparatus provided with a vacuum mechanical booster pump capable of achieving improvement of reachable pressure (lowering pressure) while securing evacuation speed in evacuation apparatus provided with the vacuum mechanical booster pump in a front stage of a vacuum pump and keeping a tank and a chamber inside or the like under a vacuum condition. SOLUTION: The evacuation apparatus is provided with the mechanical booster pump 5 at a front stage of the vacuum pump 3. The mechanical booster pump 5 includes low compression delivery ports 27a, 27b delivering at a low compression ratio stage in a process of compression in a pump chamber and a high compression delivery port 29 delivering after reaching high compression ratio and feeds air to a vacuum pump 3 from both of the low compression delivery ports 27a, 27b and the high compression delivery port 29 at a time of start of evacuation of the vacuum pump 3, and feeds air to the vacuum pump 3 from only the high compression delivery port 29 when it is reached to a middle vacuum condition which can be reached by the vacuum pump 3 after that. COPYRIGHT: (C)2008,JPO&INPIT
|
