| 摘要 |
PURPOSE:To prevent the leak-out of the processing gas from an exhaust pipe to outside during the stop of the drive of an oil rotary vacuum pump by connecting a duct connected to the gas source in the halfway of the exhaust pipe, and providing a leak valve to the duct. CONSTITUTION:The duct 35 connected to the gas source, e.g. the nitrogen gas source is connected to the exhaust pipe 30 between a valve 42 and an oil rotary vacuum pump 20. The duct 35 is provided with the leak valve 45. When the pump 20 is stopped in driving, the valves 41 and 42 are closed, and a timer 61 becomes open by the operation of an electromagnetic valve 44. Then, the operating air is supplied to the valve 45 from the air source 70, and accordingly the valve 45 is opened. The GN2 of the GN2 source is inhaled to the exhaust pipe 30 through the duct 35. Thereby, the reflux of the oil in the pump 20 is prevented. |
