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 (Archimedes screw pump (ASP) or screw pump) dates back many centuries. As a machine used for transferring water from a low-lying body of water into irrigation ditches, water is pumped 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. Archimedes Screws Turbines (ASTs) are a new form of small hydroelectric powerplant that can be applied even in low head sites. Archimedes screw generators operate in a wide range of flows (0.01 to 14.5 ) and heads (0.1 m to 10 m), 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.
Archimedes screw is named after Greek mathematician Archimedes who first described it around 234 BC, although there is evidence that the device had been used in Ancient Egypt long before his time. A screw conveyor is a similar device which transports bulk materials such as powders and grains.
The screw pump is the oldest positive displacement pump. The first records of a water screw, or screw pump, date back to Hellenistic Egypt before the 3rd century BC. The Egyptian screw, used to lift water from the Nile, was composed of tubes wound round a cylinder; as the entire unit rotates, water is lifted within the spiral tube to the higher elevation. A later screw pump design from Egypt had a spiral groove cut on the outside of a solid wooden cylinder and then the cylinder was covered by boards or sheets of metal closely covering the surfaces between the grooves.
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A windpump is a type of windmill which is used for pumping water. Windpumps were used to pump water since at least the 9th century in what is now Afghanistan, Iran and Pakistan. The use of wind pumps became widespread across the Muslim world and later spread to China and India. Windmills were later used extensively in Europe, particularly in the Netherlands and the East Anglia area of Great Britain, from the late Middle Ages onwards, to drain land for agricultural or building purposes.
In classical antiquity, the Hellenistic period covers the time in Mediterranean history after Classical Greece, between the death of Alexander the Great in 323 BC to the death of Cleopatra VII (30 BC) followed by the emergence of the Roman Empire, as signified by the Battle of Actium in 31 BC and the conquest of Ptolemaic Egypt the following year. The Ancient Greek word Hellas (Ἑλλάς, Hellás) was gradually recognized as the name for Greece, from which the word Hellenistic was derived.
A water wheel is a machine for converting the energy of flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a wheel (usually constructed from wood or metal), with a number of blades or buckets arranged on the outside rim forming the driving car. Water wheels were still in commercial use well into the 20th century but they are no longer in common use. Uses included milling flour in gristmills, grinding wood into pulp for papermaking, hammering wrought iron, machining, ore crushing and pounding fibre for use in the manufacture of cloth.
The experimental investigation of the hydrodynamics of a reversible pump-turbine reduced scale model in off-design operating conditions is presented. The onset and development of flow instabilities outside the “normal” operating range, in generating mode, ...
EPFL Doctoral Conference in Mechanics - EDCM20102010
The paper reviews recent research and development activities in the field of hydropower technology. It covers emerging and advanced technologies to mitigate flow instabilities (active and passive approach) as well as emerging magneto-rheological control te ...
PERGAMON-ELSEVIER SCIENCE LTD2019
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In the framework of the XFLEX HYDRO H2020 European Project, a 5 MW reversible Francis pump-turbine prototype, equipped with an industrial full size frequency converter, is investigated to demonstrate enhanced grid regulation capacities of variable speed hy ...