Screw Pump

a hydraulic machine whose working member is a screw; used for pumping liquids, including high-viscosity fluids. Screw pumps, also referred to as worm pumps, are a type of rotary pump. The screw pump housing contains a driving screw and one or two driven screws. The points of engagement of the screws travel longitudinally along the shaft during rotation, thus forcing out the volume of liquid contained between the turns. It is potential energy that for the most part is transmitted to the liquids, as a result of which there is a considerable increase in pressure within it.