The diagram above shows a
cross section of the Liquid Ring Vacuum Pump. It operates
on the rotary liquid piston principle, the shaft and the
impellers being the only moving parts.
The shaft and impeller assembly is mounted
eccentrically relative to the pump casing. As the
impeller rotates the service liquid ( which is
continually supplied to the pump ), is forced outwards by
centrifugal force to form a liquid ring revolving
concentric to the pump casing.
Because of the eccentric position of the impeller, the
liquid ring will move towards and away from the shaft,
resulting in a liquid piston action which displaces the
air or gases between the spaces of the impeller blades.
As the impeller rotates, the liquid is
thrown out by centrifugal force and air is drawn in
through the suction port. After the suction port is
passed, the service liquid is forced back into the spaces
between the impeller blades, gradually compressing the
air or gases. When the spaces between the impeller blades
reach the discharge point, the liquid ring will force the
air compressed between the blades into the discharge