Archimedes' screw
Encyclopedia
The Archimedes' screw, also called the Archimedean screw or screwpump, is a machine
historically used for transferring water from a low-lying body of water into irrigation
ditches. The screw pump is commonly attributed to Archimedes
on the occasion of his visit to Egypt
, but this tradition may only reflect that the apparatus was unknown before Hellenistic times and introduced in his life-time by unknown Greek
engineers.
The contact surface between the screw and the pipe does not need to be perfectly water-tight because of the relatively large amount of water being scooped at each turn with respect to the angular frequency and angular speed of the screw. Also, water leaking from the top section of the screw leaks into the previous one and so on, so a sort of mechanical equilibrium is achieved while using the machine, thus limiting a decrease in mechanical efficiency.
In some designs, the screw is fixed to the casing and they rotate together instead of the screw turning within a stationary casing. A screw could be sealed with pitch resin or some other adhesive to its casing, or, cast as a single piece in bronze, as some researchers have postulated as being the devices used to irrigate the Hanging Gardens
of Babylon
, one of the Seven Wonders of the Ancient World
. Depictions of Greek
and Roman
water screws show the screws 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.
and other places in the creation of polder
s. A part of the sea would be enclosed and the water would be pushed up out of the enclosed area, starting the process of draining the land for use in agriculture. Depending on the length and diameter of the screws, more than one machine could be used to successively lift the same water.
An Archimedes screw was used by British soils engineer Dr. John Burland in the successful 2001 stabilization of the Leaning Tower of Pisa
. Small slivers of subsoil saturated by groundwater were removed from far below the north side of the Tower, and the weight of the tower itself corrected the lean.
Archimedes screws are used in sewage treatment
plants because they cope well with varying rates of flow and with suspended solids. An auger in a snow blower
or grain elevator
is essentially an Archimedes screw.
The principle is also found in pescalators, which are Archimedes screws designed to lift fish safely from ponds and transport them to another location. This technology is primarily used at fish hatcheries as it is desirable to minimize the physical handling of fish.
The invention of the water-screw is credited to the Greek polymath Archimedes
of Syracuse in the 3rd century BC. Its tentative attribution to the 6th century BC Babylonian king Nebuchadnezzar II by the assyriologist Dalley or to pre-Hellenistic Egypt has been refuted on the grounds of "the total lack of any literary and archaeological evidence for the existence of the water-screw before ca. 250 BC". The German engineer Konrad Kyeser
, in his Bellifortis
(1405), equips the Archimedes screw with a crank mechanism. This mechanism soon replaced the ancient practice of working the pipe by treading.
It can also be found in some injection molding machines
, die casting machines and extrusion of plastics, which employ a screw of decreasing pitch to compress and melt the material. Finally, it is also used in a specific type of positive displacement air compressor
: the rotary screw air compressor. On a much larger scale, Archimedes' screws of decreasing pitch are used for the compaction
of waste material.
A screw conveyor is an Archimedes' screw contained within a tube and turned by a motor so as to deliver material from one end of the conveyor to the other. It is particularly suitable for transport of granular materials such as plastic granules used in injection molding, and cereal grains
. It may also be used to transport liquids. In industrial control applications the conveyor may be used as a rotary feeder
or variable rate feeder
to deliver a measured rate or quantity of material into a process.
and Torrs Hydro
are two reverse screw micro hydro
schemes operating in England. As a generator the screw is good at low heads, commonly found in English rivers.
Machine
A machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...
historically used for transferring water from a low-lying body of water into irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...
ditches. The screw pump is commonly attributed to Archimedes
Archimedes
Archimedes of Syracuse was a Greek mathematician, physicist, engineer, inventor, and astronomer. Although few details of his life are known, he is regarded as one of the leading scientists in classical antiquity. Among his advances in physics are the foundations of hydrostatics, statics and an...
on the occasion of his visit to Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
, but this tradition may only reflect that the apparatus was unknown before Hellenistic times and introduced in his life-time by unknown Greek
Ancient Greece
Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...
engineers.
Design
The Archimedes' Screw consists of a screw inside a hollow pipe. The screw is turned usually by a windmill or by manual labor. As the bottom end of the tube turns, it scoops up a volume of water. This amount of water will slide up in the spiral tube as the shaft is turned, until it finally pours out from the top of the tube and feeds the irrigation systems. It was mostly used for draining water out of mines or other areas of low lying water.The contact surface between the screw and the pipe does not need to be perfectly water-tight because of the relatively large amount of water being scooped at each turn with respect to the angular frequency and angular speed of the screw. Also, water leaking from the top section of the screw leaks into the previous one and so on, so a sort of mechanical equilibrium is achieved while using the machine, thus limiting a decrease in mechanical efficiency.
In some designs, the screw is fixed to the casing and they rotate together instead of the screw turning within a stationary casing. A screw could be sealed with pitch resin or some other adhesive to its casing, or, cast as a single piece in bronze, as some researchers have postulated as being the devices used to irrigate the Hanging Gardens
Hanging Gardens of Babylon
The Hanging Gardens of Babylon were considered to be one of the greatest Seven Wonders of the Ancient World, and the only one of the Wonders which may in fact have been legendary. They were purportedly built in the ancient city-state of Babylon, near present-day Al Hillah, Babil, in Iraq...
of Babylon
Babylon
Babylon was an Akkadian city-state of ancient Mesopotamia, the remains of which are found in present-day Al Hillah, Babil Province, Iraq, about 85 kilometers south of Baghdad...
, one of the Seven Wonders of the Ancient World
Seven Wonders of the Ancient World
The Seven Wonders of the World refers to remarkable constructions of classical antiquity listed by various authors in guidebooks popular among the ancient Hellenic tourists, particularly in the 1st and 2nd centuries BC...
. Depictions of Greek
History of Greece
The history of Greece encompasses the history of the territory of the modern state of Greece, as well as that of the Greek people and the areas they ruled historically. The scope of Greek habitation and rule has varied much through the ages, and, as a result, the history of Greece is similarly...
and Roman
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....
water screws show the screws 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.
Uses and history
Along with transferring water to irrigation ditches, this device was also used for reclaiming land from under sea level in the NetherlandsNetherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
and other places in the creation of polder
Polder
A polder is a low-lying tract of land enclosed by embankments known as dikes, that forms an artificial hydrological entity, meaning it has no connection with outside water other than through manually-operated devices...
s. A part of the sea would be enclosed and the water would be pushed up out of the enclosed area, starting the process of draining the land for use in agriculture. Depending on the length and diameter of the screws, more than one machine could be used to successively lift the same water.
An Archimedes screw was used by British soils engineer Dr. John Burland in the successful 2001 stabilization of the Leaning Tower of Pisa
Leaning Tower of Pisa
The Leaning Tower of Pisa or simply the Tower of Pisa is the campanile, or freestanding bell tower, of the cathedral of the Italian city of Pisa...
. Small slivers of subsoil saturated by groundwater were removed from far below the north side of the Tower, and the weight of the tower itself corrected the lean.
Archimedes screws are used in sewage treatment
Sewage treatment
Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants...
plants because they cope well with varying rates of flow and with suspended solids. An auger in a snow blower
Snow blower
A snow blower or snow thrower is a machine for removing snow from an area where it is not wanted, such as a driveway, sidewalk, roadway, railroad track, rink, runway, or houses...
or grain elevator
Grain elevator
A grain elevator is a tower containing a bucket elevator, which scoops up, elevates, and then uses gravity to deposit grain in a silo or other storage facility...
is essentially an Archimedes screw.
The principle is also found in pescalators, which are Archimedes screws designed to lift fish safely from ponds and transport them to another location. This technology is primarily used at fish hatcheries as it is desirable to minimize the physical handling of fish.
The invention of the water-screw is credited to the Greek polymath Archimedes
Archimedes
Archimedes of Syracuse was a Greek mathematician, physicist, engineer, inventor, and astronomer. Although few details of his life are known, he is regarded as one of the leading scientists in classical antiquity. Among his advances in physics are the foundations of hydrostatics, statics and an...
of Syracuse in the 3rd century BC. Its tentative attribution to the 6th century BC Babylonian king Nebuchadnezzar II by the assyriologist Dalley or to pre-Hellenistic Egypt has been refuted on the grounds of "the total lack of any literary and archaeological evidence for the existence of the water-screw before ca. 250 BC". The German engineer Konrad Kyeser
Konrad Kyeser
Konrad Kyeser was a German military engineer, author of Bellifortis , a book on siege engines popular throughout the 15th century...
, in his Bellifortis
Bellifortis
Bellifortis is the first fully illustrated manual of military technology, dating from the start of the 15th century...
(1405), equips the Archimedes screw with a crank mechanism. This mechanism soon replaced the ancient practice of working the pipe by treading.
It can also be found in some injection molding machines
Injection molding
Injection molding is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the cavity...
, die casting machines and extrusion of plastics, which employ a screw of decreasing pitch to compress and melt the material. Finally, it is also used in a specific type of positive displacement air compressor
Air compressor
An air compressor is a device that converts power into kinetic energy by compressing and pressurizing air, which, on command, can be released in quick bursts...
: the rotary screw air compressor. On a much larger scale, Archimedes' screws of decreasing pitch are used for the compaction
Compactor
A compactor is a machine or mechanism used to reduce the size of waste material or soil through compaction. A trash compactor is often used by homes and businesses to reduce the volume of trash....
of waste material.
Variants
Cereal
Cereals are grasses cultivated for the edible components of their grain , composed of the endosperm, germ, and bran...
. It may also be used to transport liquids. In industrial control applications the conveyor may be used as a rotary feeder
Rotary feeder
Rotary feeders, also known as rotary airlocks or rotary valves, are commonly used in industrial and agricultural applications as a component in a bulk or specialty material handling system. Rotary feeders are primarily used for discharge of bulk solid material from hoppers/bins, receivers, and...
or variable rate feeder
Variable rate feeder
A variable rate feeder is a piece of industrial control equipment used to deliver solid material at a known rate into some process.A number of different techniques and transport mechanisms are used, but these broadly split into these categories, in descending order of accuracy:* closed-loop...
to deliver a measured rate or quantity of material into a process.
Reverse action
If water is poured into the top of an Archimedes' screw, it will force the screw to rotate. The rotating shaft can then be used to drive an electric generator. Such an installation has the same benefits as using the screw for pumping: the ability to handle very dirty water and widely varying rates of flow at high efficiency. Settle HydroSettle Hydro
Settle Hydro is a micro hydroelectric scheme, owned by the community, in Settle, North Yorkshire.It is located on the River Ribble, at Settle Wier near Bridge End Mill. It uses part of the former mill race...
and Torrs Hydro
Torrs Hydro, New Mills
Torrs Hydro is a micro hydroelectric scheme, owned by the community, in New Mills, Derbyshire.It is located on the River Goyt, immediately after its confluence with the River Sett at the Torr weir...
are two reverse screw micro hydro
Micro hydro
Micro hydro is a term used for hydroelectric power installations that typically produce up to 100 kW of electricity. These installations can provide power to an isolated home or small community, or are sometimes connected to electric power networks....
schemes operating in England. As a generator the screw is good at low heads, commonly found in English rivers.
See also
- ArchimedesArchimedesArchimedes of Syracuse was a Greek mathematician, physicist, engineer, inventor, and astronomer. Although few details of his life are known, he is regarded as one of the leading scientists in classical antiquity. Among his advances in physics are the foundations of hydrostatics, statics and an...
- MachineMachineA machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...
- Screw-propelled vehicle
- SS ArchimedesSS ArchimedesSS Archimedes was a steamship built in Britain in 1839. She is notable for being the world's first steamship to be driven by a screw propeller....
– the first steamship driven by a screw propeller. - Screw (simple machine)Screw (simple machine)A screw is a mechanism that converts rotational motion to linear motion, and a torque to a linear force. It is one of the six classical simple machines. The most common form consists of a cylindrical shaft with helical grooves or ridges called threads around the outside...
- Spiral pumpSpiral pumpA spiral pump is a low lift pump which is composed of a a long piece of metal plating, which is wound into a coil and sealed at the top and back extremities so as to resemble a cylinder. The outer cavity serves as the inlet, while the inner tube serves as the outlet. The outlet pipe is fixed to a...
- TurbineTurbineA turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...
- VitruviusVitruviusMarcus Vitruvius Pollio was a Roman writer, architect and engineer, active in the 1st century BC. He is best known as the author of the multi-volume work De Architectura ....
Sources
- P. J. Kantert: „Manual for Archimedean Screw Pump“, Hirthammer Verlag 2008, ISBN 978-3-88721-896-6.
- P. J. Kantert: „Praxishandbuch Schneckenpumpe“, Hirthammer Verlag 2008, ISBN 978-3-88721-202-5.
External links
- Technology and Culture Volume 44, Number 1, January 2003 (PDF) Dalley, Stephanie. Oleson, John Peter. "Sennacherib, Archimedes, and the Water Screw: The Context of Invention in the Ancient World"
- The Turn of the Screw: Optimal Design of an Archimedes Screw, by Chris Rorres, PhD.
- archimedean screw pump, how to build a functioning Archimedes screw pump from modern materials
- Web archive backup: Plywood archimedean screw water pump, how to build a functioning Archimedes screw pump (Archived 2009-10-25)
- Manual for Screw Pumps, publisher
- "Archimedean Screw" by Sándor Kabai, Wolfram Demonstrations ProjectWolfram Demonstrations ProjectThe Wolfram Demonstrations Project is hosted by Wolfram Research, whose stated goal is to bring computational exploration to the widest possible audience. It consists of an organized, open-source collection of small interactive programs called Demonstrations, which are meant to visually and...
, 2007. - "The Archimedes Screw"
- http://www.telegraph.co.uk/culture/art/architecture/7907298/Solving-the-800-year-mystery-of-Pisas-Leaning-Tower.html
- Archimede Screw
- Archimedean Screw Generator