A liquid ring vacuum pump is easy to operate and is used in a number of applications across various industries. A liquid band pump works together with a sealant needed in its operation. This liquid can be water, essential oil or any other solvent which is rotated by an impeller within the casing of the pump.
As the shaft turns, a liquid ring is created by the centrifugal force generated by the rotating impeller. This pressure holds the liquid band against the inner wall structure of the pumping chamber. Since the impeller is located eccentric to the pumping chamber, the depth of access of the blades into the liquid ring reduces and raises as the impeller rotates. This creates increasing cellular volume on the inlet slot side, creating vacuum.
On the discharge port side, the impeller cell volume decreases as the blades move further into the liquid ring. This escalates the pressure until discharge takes place through the discharge slot.
A continuous flow of refreshing sealing liquid comes to the pump via the sealing-liquid inlet.
Regarding the two-stage liquid 
band pump, the discharge from the first stage does not discharge to atmosphere. Rather, the 1st stage discharges through the manifold resulting in the second stage as well as through a discharge port positioned in the Liquid-Ring Vacuum Pump china intermediate plate between your first- and second-stage impellers.