| 摘要 |
PURPOSE:To securely prevent air which leaks into the gear box of a mechanical booster pump MB from blowing backward to a leak detector by linking the gear box with the exhaust side in an auxiliary pump through a check valve. CONSTITUTION:A roughing vacuum path 4 where a roughing vacuum valve 5, the mechanical booster pump 6, and an oil rotary vacuum pump 7 are arrayed is connected to the exhaust path 3 from a fitting port 1a for a body 1 to be inspected to the leak detector. Then the air which leaks into the gear box 6a of the MB 6 is discharged to the exhaust side of the pump 7 linked with the gear box 6a while disabled to flow backward. Further, the leak area in the gear box 6a which is guided to the exhaust side of the pump 7 can not be enter the path 3 from the body 1 to be inspected to the leak detector 2 without flowing backward through the pump 7 and two pumps of a preceeding- stage MB 6, so the possibility that blow gas contained in the air leaking into the gear box 6a of the MB 6 is detected by the leak detector 2 is eliminated substantially completely. |
