History and Design of the Archimedes’ Screw
– 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 was used to lift water from the Nile and consisted of tubes wound around a cylinder.
– Some researchers propose that the device was used to irrigate the Hanging Gardens of Babylon.
– The screw pump was later introduced from Egypt to Greece and described by Archimedes.
– The Archimedes screw consists of a screw inside a hollow pipe.
– The screw is usually turned by windmill, manual labor, cattle, or a motor.
– The bottom end of the screw scoops up water, which is pushed up the tube by the rotating helicoid.
– The contact surface between the screw and the pipe does not need to be perfectly watertight.
– In some designs, the screw is fused to the casing and they both rotate together.
Uses of the Archimedes’ Screw
– The screw was used for water transport in irrigation systems and for dewatering mines.
– It was used for draining land underneath the sea in the Netherlands and creating polders.
– Archimedes screws are used in sewage treatment plants and can handle varying flow rates and suspended solids.
– Augers in snow blowers and grain elevators are essentially Archimedes screws.
– Escalators designed to lift fish safely from ponds also use the principle of the Archimedes screw.
Variants of the Archimedes’ Screw
– A screw conveyor is an Archimedes screw contained within a tube and turned by a motor.
– It is used for transporting granular materials and liquids in industrial applications.
– In injection molding, a variant of the Archimedes screw is used.
– Screw turbines (ASTs) are a new form of generator for small hydroelectric power plants.
– ASTs have a low rotation speed to reduce negative impacts on aquatic life and fish.
Other Facts about the Archimedes’ Screw
– The Archimedes screw is named after Greek mathematician Archimedes.
– It is one of the earliest hydraulic machines and has been used for centuries.
– Archimedes never claimed credit for its invention, but it was attributed to him later.
– The screw pump was also used in the successful stabilization of the Leaning Tower of Pisa.
– Archimedes screws are also used in chocolate fountains.
Reverse Action and Applications of the Archimedes’ Screw
– Water fed into the top of an Archimedes screw forces it to rotate.
– The rotating shaft can be used to drive an electric generator.
– Reverse screw micro hydro schemes operate in England, such as Settle Hydro and Torrs Hydro.
– The screw is efficient in handling dirty water and varying flow rates.
– The first reverse screw hydropower in the United States opened in Meriden, Connecticut in 2017. Source: https://en.wikipedia.org/wiki/Archimedean_screw
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. Because it can not generate pressure it is not a pump.[further explanation needed] 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 screws turbine acts 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 (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 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.
