| 摘要 |
PURPOSE:To prevent overloading of a mechanical booster valve, by providing a branch passage between a welding room and a vacuum valve, vacuum sucking the welding room and connecting a mechanical booster pump and the welding room. CONSTITUTION:A branch passage 8 is provided between a welding room 1 and a vacuum valve 4 and the second vacuum valve 9 is installed. While an object to be welded is being set in the welding room 1, the vacuum valve 4 and the second vacuum valve 9 are closed, an oil rotary pump 3 is operated and the part between the pump 3 and the valve 4 and the second valve 9 is evacuated. A mechanical booster pump 2 is operated by this process. When setting of the object to be welded is completed, the second valve 9 is opened and the welding room is evacuated through the branch passage 8. When the internal pressure of the branch passage 8 becomes the driving start pressure of the mechanical booster pump 2, the second valve 9 is closed at once, the valve 4 is opened, and the welding room 1 is evacuated. Thus, the mechanical booster valve 2 is not overloaded. |
