| 摘要 |
A valve arrangement for a vacuum pump assembly selectively opens and closes communication between a vacuum pump, evacuation vessel, and a volume to be evacuated. The valve arrangement allows the evacuation vessel and any conduit connecting the vacuum pump and evacuation vessel to the volume to first be evacuated without providing a vacuum to the volume. The valve arrangement also allows the volume to be connected to the evacuation vessel but cut-off from the vacuum pump so that at initial stages of the evacuation process for the volume dead air contained within the volume may be communicated to the evacuation vessel rather than drawn out by the vacuum pump. Once the dead air, or portions thereof, has been removed from the volume, the valve arrangement may cut-off communication with the evacuation vessel, establish communication between the vacuum pump and the volume, and allow the vacuum pump to provide negative air pressure to the volume so that the volume may be evacuated.
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