Liquid Ring Compressors
In this design the rotor runs in a ring of liquid which seals and cools the compressed gas.
Two types are available – the single-acting, circular stator, and the double-acting, oval stator. Both are illustrated in Figure 22. They both have a built-in pressure ratio, but the double-lobe body is more suitable for higher pressures (up to 7 bar). A variety of liquids can be used; water is a common one, but non-corrosive liquids can also be used according to application. The presence of a large quantity of liquid means that churning losses are high, but cooling is very good, so isothermal conditions are approached at the expense of mechanical efficiency. These units are also useful as vacuum pumps.