A liquid ring vacuum pump has an impeller with blades mounted on a center hub located in a cylindrical body but off-set from the guts.
In Determine 1 to the proper, you can view the blades near the the surface of the pump are closer to the outside wall than at the sides and bottom of the pump. You can see this more obviously in Figure 2.
The impeller sits between 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 the following. Prior to starting the pump, it should be Gas-cooling Vacuum Pump partially filled with the liquid sealant. The liquid could be water (rendering it a water ring pump), oil or a solvent, dependant on the application.