A liquid ring vacuum pump is simple to operate and is used in several applications across various industries. A liquid ring pump works with a sealant necessary in its operation. This liquid can be water, essential oil or any other solvent which is definitely rotated by an impeller within the casing of the pump.
As the shaft turns, a liquid band is established by the centrifugal force produced by the rotating impeller. This force holds the liquid ring against the inner wall structure of the pumping chamber. Because the impeller is situated eccentric to the pumping chamber, the depth of entry of the blades in to the liquid ring decreases and boosts as the impeller rotates. This creates increasing cell volume on the inlet interface side, creating vacuum.
On the discharge interface side, the impeller cell volume decreases as the blades move further in to the liquid ring. This increases the pressure until discharge takes place through the discharge port.
A continuous flow of fresh sealing liquid comes to 
the pump via the sealing-liquid inlet.
In the case of the Liquid-Ring Vacuum Pump china two-stage liquid band pump, the discharge from the first stage will not discharge to atmosphere. Instead, the first stage discharges through the manifold leading to the second stage as well as through a discharge interface located in the intermediate plate between your first- and second-stage impellers.