A liquid band vacuum pump is easy to operate and is utilized in several applications across various industries. A liquid band pump works together with a sealant required in its operation. This liquid could be water, oil or any various other solvent which is rotated by an impeller within the casing of the pump.
As the shaft turns, a liquid ring is established by the centrifugal force produced by the rotating impeller. This drive holds the liquid ring against the inner wall of the pumping chamber. Since the impeller is situated eccentric to the pumping chamber, the depth of entry of the blades into the liquid ring reduces and increases as the impeller rotates. This Liquid-Ring Vacuum Pump creates increasing cell quantity on the inlet slot side, creating vacuum.
On the discharge interface side, the impeller 
cell volume decreases as the blades move further in to the liquid band. This escalates the pressure until discharge takes place through the discharge slot.
A continuous flow of fresh sealing liquid is supplied to the pump via the sealing-liquid inlet.
In the case of the two-stage liquid band pump, the discharge from the initial stage will not discharge to atmosphere. Rather, the first stage discharges through the manifold leading to the second stage as well as through a discharge interface situated in the intermediate plate between your first- and second-stage impellers.