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The Archimedes' screw, also known as the Archimedean screw, hydrodynamic screw, water screw or Egyptian screw, is one of the earliest documented
Archimedes screws are used in
The Archimedes' screw, also known as the Archimedean screw, hydrodynamic screw, water screw or Egyptian screw, is one of the earliest documented hydraulic
Hydraulics () is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counterpart of pneumatics, which concer ...
machines. It was so-named after the Greek mathematician Archimedes
Archimedes of Syracuse ( ; ) was an Ancient Greece, Ancient Greek Greek mathematics, mathematician, physicist, engineer, astronomer, and Invention, inventor from the ancient city of Syracuse, Sicily, Syracuse in History of Greek and Hellenis ...
who first described it around 234 BC, although the device had been developed in Egypt
Egypt ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northe ...
earlier in the century. It is a reversible hydraulic machine that can be operated both as a pump or a power generator.
As a machine
A machine is a physical system that uses power to apply forces and control movement to perform an action. The term is commonly applied to artificial devices, such as those employing engines or motors, but also to natural biological macromol ...
used for lifting water from a low-lying body of water into irrigation
Irrigation (also referred to as watering of plants) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has bee ...
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
A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple ani ...
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.
History
Earliest records
The screw pump is the oldestpositive displacement pump
A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic or pneumatic energy.
Mechanical pumps serve in a wide range of applications such ...
. The first records of a water screw, or screw pump, date back to Hellenistic Egypt
The Ptolemaic Kingdom (; , ) or Ptolemaic Empire was an ancient Greek polity based in Ancient Egypt, Egypt during the Hellenistic period. It was founded in 305 BC by the Ancient Macedonians, Macedonian Greek general Ptolemy I Soter, a Diadochi, ...
before the 3rd century BC. The Egyptian screw, used to lift water from the Nile
The Nile (also known as the Nile River or River Nile) is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa. It has historically been considered the List of river sy ...
, 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.
Some researchers have proposed this device was used to irrigate the Hanging Gardens of Babylon
The Hanging Gardens of Babylon were one of the Seven Wonders of the Ancient World listed by Hellenic culture. They were described as a remarkable feat of engineering with an ascending series of tiered gardens containing a wide variety of tree ...
, one of the Seven Wonders of the Ancient World
The Seven Wonders of the Ancient World, also known as the Seven Wonders of the World or simply the Seven Wonders, is a list of seven notable structures present during classical antiquity, first established in the 1572 publication '' Octo Mundi M ...
. A cuneiform inscription of Assyria
Assyria (Neo-Assyrian cuneiform: , ''māt Aššur'') was a major ancient Mesopotamian civilization that existed as a city-state from the 21st century BC to the 14th century BC and eventually expanded into an empire from the 14th century BC t ...
n King Sennacherib
Sennacherib ( or , meaning "Sin (mythology), Sîn has replaced the brothers") was the king of the Neo-Assyrian Empire from 705BC until his assassination in 681BC. The second king of the Sargonid dynasty, Sennacherib is one of the most famous A ...
(704–681 BC) has been interpreted by Stephanie Dalley
Stephanie Mary Dalley FSA (''née'' Page; March 1943) is a British Assyriologist and scholar of the Ancient Near East. Prior to her retirement, she was a teaching Fellow at the Oriental Institute, Oxford. She is known for her publications of ...
to describe casting water screws in bronze some 350 years earlier. This is consistent with Greek historian Strabo
Strabo''Strabo'' (meaning "squinty", as in strabismus) was a term employed by the Romans for anyone whose eyes were distorted or deformed. The father of Pompey was called "Gnaeus Pompeius Strabo, Pompeius Strabo". A native of Sicily so clear-si ...
, who describes the Hanging Gardens as irrigated by screws.
Archimedes' role
The screw pump was later introduced from Hellenistic Egypt to Greece. It was described byArchimedes
Archimedes of Syracuse ( ; ) was an Ancient Greece, Ancient Greek Greek mathematics, mathematician, physicist, engineer, astronomer, and Invention, inventor from the ancient city of Syracuse, Sicily, Syracuse in History of Greek and Hellenis ...
, on the occasion of his visit to Egypt
Egypt ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northe ...
, circa 234 BC. This tradition may reflect only that the apparatus was unknown to the Greeks before Hellenistic
In classical antiquity, the Hellenistic period covers the time in Greek history after Classical Greece, between the death of Alexander the Great in 323 BC and the death of Cleopatra VII in 30 BC, which was followed by the ascendancy of the R ...
times. Athenaeus of Naucratis
Athenaeus of Naucratis (, or Nαυκράτιος, ''Athēnaios Naukratitēs'' or ''Naukratios''; ) was an ancient Greek rhetorician and grammarian, flourishing about the end of the 2nd and beginning of the 3rd century AD. The ''Suda'' says on ...
quotes a certain Moschion in a description on how Hiero II of Syracuse
Hiero II (; also Hieron ; ; c. 308 BC – 215 BC) was the Greek tyrant of Syracuse, Greek Sicily, from 275 to 215 BC, and the illegitimate son of a Syracusan noble, Hierocles, who claimed descent from Gelon. He was a former general of Pyrrhus ...
commissioned the design of the '' Syracusia'', a luxury ship which would be a display of naval power. It is said to have been the largest ship built in classical antiquity
Classical antiquity, also known as the classical era, classical period, classical age, or simply antiquity, is the period of cultural History of Europe, European history between the 8th century BC and the 5th century AD comprising the inter ...
and was launched by Archimedes who designed device with a revolving screw-shaped blade inside a cylinder to remove any potential water leaking through the hull. Archimedes' screw was turned by hand, and could also be used to transfer water from a low-lying body of water into irrigation canals.
Archimedes never claimed credit for its invention, but it was attributed to him 200 years later by Diodorus
Diodorus Siculus or Diodorus of Sicily (; 1st century BC) was an ancient Greek historian from Sicily. He is known for writing the monumental universal history '' Bibliotheca historica'', in forty books, fifteen of which survive intact, b ...
, who believed that Archimedes invented the screw pump in Egypt. Depictions of Greek
Greek may refer to:
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group
*Greek language, a branch of the Indo-European language family
**Proto-Greek language, the assumed last common ancestor of all kno ...
and Roman
Roman or Romans most often refers to:
*Rome, the capital city of Italy
*Ancient Rome, Roman civilization from 8th century BC to 5th century AD
*Roman people, the people of Roman civilization
*Epistle to the Romans, shortened to Romans, a letter w ...
water screws show them being powered by a human treading on the outer casing to turn the entire apparatus as one piece, which would require that the casing be rigidly attached to the screw.
Development and modern use
German engineer Konrad Kyeser equipped the Archimedes screw with a crank mechanism in his '' Bellifortis'' (1405). This mechanism quickly replaced the ancient practice of working the pipe by treading. The world's first seagoingsteamship
A steamship, often referred to as a steamer, is a type of steam-powered vessel, typically ocean-faring and seaworthy, that is propelled by one or more steam engines that typically move (turn) propellers or paddlewheels. The first steamships ...
driven by a screw propeller was the SS ''Archimedes'', which was launched in 1839 and named in honor of Archimedes and his work on the screw. Developments in maritime transport occurred over the next 180 years from the Fawcett, Preston and Company double blade design and patents by Sharrow Marine to address rotary propulsion and flow control on boating vessels through loop propellers. Electricity generation through hydropower pumps such as the Meriden project operated by New England Hydropower also uses Archimedes screw to direct water into the top, rather than the bottom, of the screw which forces it to rotate.
Archimedes screws are used in sewage treatment
Sewage treatment is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable to discharge to the surrounding environment or an intended reuse application, thereby preventing water p ...
plants because they cope well with varying rates of flow and with suspended solids. Screw turbine
file:Archimedes-screw one-screw-threads with-ball 3D-view animated smal back.gif, Reverse action of the Archimedean screw, the principle of the screw turbine gaining energy from water flowing down through the screw
file:Helical screw single double ...
s (ASTs) are a new form of generator for small hydroelectric powerplants that could be applied even in low-head sites. The low rotation speed of ASTs reduces negative impacts on aquatic life and fish. This technology is used primarily at fish hatcheries to lift fish safely from ponds and transport them to another location. An Archimedes screw was used in the successful 2001 stabilization of the Leaning Tower of Pisa
The Leaning Tower of Pisa ( ), or simply the Tower of Pisa (), is the , or freestanding bell tower, of Pisa Cathedral. It is known for its nearly four-degree lean, the result of an unstable Foundation (engineering), foundation. The tower is on ...
. Small amounts of subsoil
Subsoil is the layer of soil under the topsoil on the surface of the ground. Like topsoil, it is composed of a variable mixture of small particles such as sand, silt and clay, but with a much lower percentage of organic matter and humus. The su ...
saturated by groundwater were removed from far below the north side of the tower, and the weight of the tower itself corrected the lean.
Other inventions using Archimedes screws include the auger conveyor in a snow blower
A snow blower or snowblower or snow thrower is a machine for removing snow from an area where it is problematic, such as a driveway, sidewalk, roadway, railroad track, ice rink, or runway. The commonly used term "snow blower" is a misnomer, a ...
, grain elevator
A grain elevator or grain terminal is a facility designed to stockpile or store grain. In the grain trade, the term "grain elevator" also describes a tower containing a bucket elevator or a pneumatic conveyor, which scoops up grain from a lowe ...
, concrete mixer
A concrete mixer (also cement mixer) is a device that homogeneously combines cement, Construction aggregate, aggregate (e.g. sand or gravel), and water to form concrete. A typical concrete mixer uses a revolving drum to mix the components. For ...
and chocolate fountain.
Design
The Archimedes screw consists of a screw (a helical surface surrounding a central cylindrical shaft) inside a hollow pipe. The screw is usually turned by windmill, manual labor, cattle, or by modern means, such as a motor. As the shaft turns, the bottom end scoops up a volume of water. This water is then pushed up the tube by the rotating helicoid until it pours out from the top of the tube. The contact surface between the screw and the pipe does not need to be perfectly watertight, as long as the amount of water being scooped with each turn is large compared to the amount of water leaking out of each section of the screw per turn. If water from one section leaks into the next lower one, it will be transferred upwards by the next segment of the screw. In some designs, the screw is fused to the casing and they both rotate together, instead of the screw turning within a stationary casing. The screw could be sealed to the casing with pitch resin or other adhesive, or the screw and casing could be cast together as a single piece in bronze. The design of the everyday Greek and Roman water screw, in contrast to the heavy bronze device ofSennacherib
Sennacherib ( or , meaning "Sin (mythology), Sîn has replaced the brothers") was the king of the Neo-Assyrian Empire from 705BC until his assassination in 681BC. The second king of the Sargonid dynasty, Sennacherib is one of the most famous A ...
, with its problematic drive chains, has a powerful simplicity. A double or triple helix
A helix (; ) is a shape like a cylindrical coil spring or the thread of a machine screw. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is for ...
was built of wood strips (or occasionally bronze sheeting) around a heavy wooden pole. A cylinder was built around the helices using long, narrow boards fastened to their periphery and waterproofed with pitch.
Studies show that the volume of flow passes through Archimedes screws is a function of inlet depth, diameter and rotation speed of the screw. Therefore, the following analytical equation could be used to design Archimedes screws: