The Archimedes' screw, also known as the Archimedean screw, hydrodynamic screw, water screw or Egyptian screw, is one of the earliest hydraulic machines. Using Archimedes screws as water pumps dates back many centuries. As a machine used for lifting water from a low-lying body of water into irrigation ditches, water is lifted by turning a screw-shaped surface inside a pipe. In the modern world, Archimedes screw pumps are widely used in wastewater treatment plants and for dewatering low-lying regions. Run in reverse, Archimedes screw turbines act as a new form of small hydroelectric powerplant that can be applied even in low head sites. Such generators operate in a wide range of flows and heads, including low heads and moderate flow rates that is not ideal for traditional turbines and not occupied by high performance technologies. The Archimedes screw is a reversible hydraulic machine, and there are several examples of Archimedes screw installations where the screw can operate at different times as either pump or generator, depending on needs for power and watercourse flow.
Modern Archimedes' screw which have replaced some of the windmills used to drain the polders at Kinderdijk in the Netherlands
Archimedes screw as a form of art by Tony Cragg at 's-Hertogenbosch in the Netherlands
An Archimedes' screw seen on a combine harvester
A water pump in Egypt from the 1950s which uses the Archimedes' screw mechanism
A screw turbine is water turbine that converts the potential energy of water on an upstream level into work. This hydropower converter is driven by the weight of water, similar to water wheels, and can be considered as a quasi-static pressure machine. Archimedes screw generators operate in a wide range of flows and heads, including low heads and moderate flow rates that are not ideal for traditional turbines and not occupied by high performance technologies.
Two parallel screw turbines capable of producing 75 kW each, in Monmouth, Wales
A screw turbine at a small hydro power plant in Goryn, Poland
12 kW screw turbine at the Cragside estate