The working parts of the SHREEJI pump consists of a multi-vane impeller mounted eccentrically in a round casing which is partly filled with liquid (usually water). As the impeller rotate the liquid is thrown by centrifugal force to from a liquid ring which is concentric with the periphery of the casing. Due to the eccentric position of the impeller relative to the casing and liquid ring, the spaces between the impeller vanes fill with liquid during rotation and any air or gas trapped in the impeller space or cell is compressed and discharged from the casing through the outlet part leaving the cell available to receive air or gas as it is presented to the inlet port of the casing. In addition to being the compressing medium the liquid-ring performs three other important functions. It absorbs the heat generated by compression and friction. It absorbs any liquid slugs or vapor entering with the gas stream. It will also absorb and wash out contaminants entrained in the gas.