Working of a Vacuum Pumps
1. The gas entering via the suction port is conveyed into the impeller casing via AB and
trapped in the space between two impeller blades.
2. As the impeller rotates — eccentrically to the liquid ring and casing — the volume between the blades increases creating
vacuum.
3. As the cycle progresses towards the discharge port the volume decreases since the liquid ring creates compression.
This compression continues until the gas is discharged through the discharge port CD.
A small amount of seal liquid is discharged with the gas so it is necessary to supply make-up continuously.
This make-up liquid also maintains the liquid ring and absorbs the heat energy generated by the compression.
I = Suction phase
II = Compression phase
