Screw pump different applications and handling fluids with varying characteristics. Each ‘screw pump' operates on the same basic principle of a screw turning to isolate a volume of fluid and convey it. However, the mechanical design of each is different. The primary difference is the number of screws: one, two, three or more. The screw pump was described by Archimedes on the occasion of his visit to Egypt. This suggests that the apparatus was unknown to the Greeks before Hellenistic times. A cuneiform inscription of Assyrian king Sennacherib (704–681 BC) has been interpreted by Stephanie Dalley to describe casting water screws in
Screw pump bronze some 350 years earlier. This is consistent with classical author Strabo, who describes the Hanging Gardens as watered by screws. Screw pump A screw pump is a positive-displacement (PD) pump that use one or several screws to move fluids or solids along the screw(s) axis. In its simplest form (the Archimedes' screw pump), a single screw rotates in a cylindrical cavity, thereby moving the material along the screw's spindle. This ancient construction is still used in many low-tech applications, such as irrigation systems and in agricultural machinery for transporting grain and other solids. Development of the screw pump has