[[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.]]
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The Archimedes Screw (named after a Greek mathematician) is though to have been around since 250 B.C.E. However, archaeological evidence has led others to posit its earlier invention in Assyria (modern day Iraq) or Egypt; Archimedes simply improved upon an earlier design.<ref> [http://www.archimedeshydroscrew.com/archimedes-screw-pump/ The basic principle of an Archimedes screw pump]. Archimedeshydroscrew.com</ref>
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> [http://www.ehow.com/how_8725014_build-handpowered-water-pump.html How to build and hand-powered water pump.] By Andrew Latham, eHow Contributor. </ref>
===Suitable conditions===
The distribution, today, of the water lifting Archimedes Screw is in the Nile-delta region of Egypt.
A major advantage of these pumps is variable pumping at constant speed, because the output (up to design capacity) is controlled by the sump level and equals the influent flow rate. The disadvantages are the inducement of turbulence, the release of odors and other volatile substances (if using for wastewater), and the relatively high initial cost (if using metal components, but not wooden). 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 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>
===Construction, operations and maintenance===
This small scale Archimedes Screw is a model to understand the concept of the water lifting device. The ones built by farmers are made of bamboo or other wood, usually. A working Archimedes Screw can be made using local (or cheap) materials in your region. The following device is an ''open screw''.
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|right|<center>Tornillo de Arquímedes /<br> Archimedes' screw</center>}}
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===References===
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===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.
