| 摘要 |
PURPOSE:To prevent overloading of a mechanical booster pump, by providing an absorber between a vacuum valve and the mechanical booster pump and vacuum evacuating the part between the vacuum valve and mechanical booster pump beforehand. CONSTITUTION:In an evacuating system, an absorber 7 is provided between a vacuum valve 2 and a mechanical booster pump 3. While an object to be welded is being set in a welding room 1, the part between the vacuum valve 2 and mechanical booster pump 3 and the inside of the absorber 7 is vacuum evacuated to a pressure of about 0.01Torr. By selecting the capacity of the absorber 7 properly, the pressure of air that flows out from the welding room 1 can be reduced in the absorber 7. By selecting the volume of the absorber 7 to make the pressure after reduction lower than the starting pressure of the mechanical booster pump 3, the stable operation can be obtained without overloading the mechanical booster pump. |
