A liquid ring vacuum pump comes with an impeller with blades mounted on a center hub situated in a cylindrical body but off-set from the guts.
In Physique 1 to the proper, you can see the blades near the the 
surface of the pump are nearer to the outside wall than at the sides and bottom of the pump. You can view this more Super Power Lock obviously in Figure 2.
The impeller sits among two end plates (port plates) which have shaped holes cut into them called ports.
The pump takes a liquid (also called the sealant) to create vacuum as follows. Before you start the pump, it must be partially filled with the liquid sealant. The liquid could be water (rendering it a water ring pump), essential oil or a solvent, dependant on the application.