A screw pump is a type of hydraulic pump "Pump (hydraulic)") considered positive displacement, which differs from the usual ones, better known as centrifugal pumps. This pump uses an eccentric helical screw "Helix (geometry)") that moves inside a sleeve and causes liquid to flow between the screw and the sleeve.

It is specifically indicated for pumping viscous fluids, with high solids content, that do not need to be stirred or that form foams if agitated. As the screw pump displaces the liquid, it does not suffer sudden movements, and can even pump whole grapes.

One of its uses is to pump sludge from the different stages of the treatment plants, and can even pump dehydrated sludge from filter presses with 22-25% dryness.

This type of pumps are widely used in the oil industry worldwide, for the pumping of highly viscous crude oils with appreciable solids content. New developments of these pumps allow multiphase pumping.

In this type of pumps they can operate with fixed flows at their discharge, even when pumping against a variable pressure network. Making them excellent pumping equipment to use in oil collection networks. In the case of centrifugal pumps, the flow delivered depends on the pressure at its discharge.