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[[Image:arch screw icon.png|right|80px]]
[[Image:archimedes screw.jpg|thumb|right|200px|Farmers in Egypt's Nile delta turn a traditional (enclosed) screw by hand to irrigate a field. Photo: [http://www.waterencyclopedia.com/Po-Re/Pumps-Traditional.html#b Waterencyclopedia.com]]]
[[File:Archimedes-screw one-screw-threads with-ball 3D-view animated small.gif|thumb|250px|Archimedes' screw was operated by hand and could raise water efficiently. Animated GIF: [http://demonstrations.wolfram.com/ArchimedeanScrew/ Wolfram Demonstrations Project.]]]
[[Image:arch screw 2.jpg|thumb|right|200px|An Egyptian farmer turning an Archimedes screw by hand to irrigate a field. [https://www.cs.drexel.edu/~crorres/Archimedes/Screw/Applications.html Photo:] Helen and Frank Schreider of the National Geographic staff.]]
The Archimedes Screw is basically a large helix, open at both ends and encased within a watertight cylinder. It operates with the cylinder somewhat tilted from vertical. When the open lower end of the cylinder is placed in water and the screw is turned, water trapped between the cylinder and the threads of the screw rises. Successive revolutions will raise the water thread-by-thread until it emerges at the top of the cylinder.
It can be used where the water needs to be raised less than 1.5 meters (5 feet). In such cases, it is perhaps the most efficient of the ancient methods, because two men can raise an enormous volume of water in less than an hour. The Archimedes Screw has been widely used over the centuries, especially to raise irrigation water and for land drainage, often being powered by people or animals. Besides being of simple construction, it has the additional advantage of being able to move water that contains mud, sand, or gravel.
'''There are two types of the Archimedes Screw:''' <br>
* The ''open screw'', which rotates in a trough. It consists of a torque tube to which spiral flightsare attached, a lower submerged bearing, an upper radial and thrust bearing, a gear reducer (typically driven by an electric motor), and a trough in which the screw rotates at a constant speed. The limiting speed ranges from 20 rev/min in large pumps to 75 rev/min in small ones and cannot be exceeded without water spilling over the top of the screw.
* The ''enclosed screw'', in which both the screw and an enclosing cylinder rotate. Except for the following differences, the enclosed screw pump is similar to the open type:
- Because the flights are welded to the outer cylinder, there is no slippage (backflow). If the pump is stopped, the water is retained between the flights. The lower bearing (a self-aligning set of rollers mounted above the highwater level) is easily accessible. The rollers carry most of the radial load.<br>
- Because there is no slippage, the efficiency of the pump is very high and stays high even at low discharge.<br>
- A massive concrete structure is not needed.
====Modern uses====
The Archimedes Screw is still used today in some limited applications (usually electrically-powered), and can range in size from a quarter of an inch to nearly 4 meters (12 feet) in diameter. A large screw or banks of screws may be used to pump rainstorm runoff or to lift water or wastewater, for example.
Archimedes' screws, now called screw conveyors, are also used today primarily to propel dry bulk materials. However, if you do not have access to a generator pump and need a low-tech solution to raise water, it doesn't get much easier and low-tech than an Archimedes' screw. <ref> [httphttps://www.ehow.com/how_8725014_buildhow_5016689_build-handpoweredsimple-water-pump.html How to build and hand-powered water pump.] By Andrew Latham, eHow Contributor. </ref>
==Construction, operations and maintenance=Suitable conditions===The distribution, today, of the water lifting Archimedes Screw is in the Nile-delta region of Egypt.
==Suitable conditions=Construction, operations and maintenance===A major advantage of these pumps This small scale Archimedes Screw is variable pumping at constant speed, because the output (up a model to design capacity) is controlled by understand the sump level and equals concept of the influent flow ratewater lifting device. The disadvantages ones built by farmers are the inducement made of turbulencebamboo or other wood, the release of odors and other volatile substances (if usually. A working Archimedes Screw can be made using for wastewater), and the relatively high initial cost local (if using metal components, but not woodenor cheap)materials in your region. But when comparing costs with those of other types of pumps, consider the cost of the total system, including all piping, wet or dry wells, screens, fittings, valves, variable-speed controls, and other accessories as well as operating and maintenance costs. Note that operators like The following device is an ''open screw pumps because the good ones, when properly installed, are so trouble-free. <ref> [http://uotechnology.edu.iq/dep-building/LECTURE/sanitary%20&%20environmental/third_class/Water%20Networks%20and%20Equipment/D-pumps-3rd%20Class.pdf Pumps and Pumping Stations, 3rd Class.] By Dr. Sataa Al-Bayati. University of Technology - Iraq''.</ref>
====Materials====
This simple screw pump can be viewed as a series of ramps around a central axle. As you turn the PVC pipe, you carry the water in small lifts from one ramp to another until it pours out of the top. It is much easier to pump water with a conveyor screw than to lift the water vertically, just like walking along a winding mountain path is easier than climbing straight up.
===Manuals, videos and links=== {{#ev:youtube|5gq3Vm4vifU|200|auto|<center>Tornillo de Arquímedes /<br> Archimedes' screw</center>}}<br>* VIDEO: [http://youtu.be/5gq3Vm4vifU Tornillo de Arquímedes / Archimedes' screw]. An animated model, showing how the mechanics of the Archimedes Screw works to bring water up from a river. ===References===
<references/>
===Acknowledgements===
* [http://www.waterencyclopedia.com/Po-Re/Pumps-Traditional.html#b Pumps, traditional]. Waterencyclopedia.com.
* Dr. Sataa Al-Bayati, [http://uotechnology.edu.iq/dep-building/LECTURE/sanitary%20&%20environmental/third_class/Water%20Networks%20and%20Equipment/D-pumps-3rd%20Class.pdf Pumps and Pumping Stations, 3rd Class.] University of Technology - Iraq.