What pumping device did Leonardo da Vinci design with a helical screw?

Leonardo da Vinci designed a screw pump that used a helical surface to raise water.

A screw pump moves liquid along a rotating spiral inside a cylinder or trough. As the screw turns, water is carried upward through the spaces between the spiral and the surrounding housing. Leonardo studied this mechanism in the context of hydraulics, canals, drainage, and machines for moving water.

The principle was much older than Leonardo. Archimedes is traditionally associated with the water screw, and ancient devices based on the same idea were already known. Leonardo’s contribution was to draw, analyze, and adapt hydraulic machinery as part of his broader engineering investigations.

A screw pump is different from a water wheel. A water wheel extracts energy from moving water, while a screw pump uses mechanical energy to move water, usually upward or against a pressure difference.