The Archimedes' screw, Archimedean screw, or screwpump is a machine historically used for transferring water from a low-lying body of water into irrigation ditches. A machine is any device that uses Energy to perform some activity Irrigation is an artificial application of water to the soil usually for assisting in growing crops It was one of several inventions and discoveries traditionally attributed to Archimedes in the 3rd century BC. Archimedes of Syracuse ( Greek:) ( c. 287 BC – c 212 BC was a Greek mathematician, Physicist, Engineer The 3rd century BC started the first day of 300 BC and ended the last day of 201 BC
Contents |
Workings
The machine consists of a screw inside a hollow pipe. Look up SpecialSearch/{{lcscrew}}}}}|{{{2|{{{1|screw}}}}}} It was invented by Archimedes in around 250 BC or in Greece earlier. A screw can be thought of as an inclined plane (another simple machine) wrapped around a cylinder. This article deals with the physical structure For related terms see Canal inclined plane, Cable railway, Funicular, or Fixed-wing In Physics, especially Mechanics, a simple machine is a mechanical device that changes the direction or magnitude of a Force.
The screw is turned (usually by a windmill or by manual labour). A windmill is a machine that is powered by the energy of the wind 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 syms.
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 speed of the screw. Do not confuse with Angular velocity In Physics (specifically Mechanics and Electrical engineering) angular frequency Also, water leaking from the top section of the screw leaks into the previous one and so on, so a sort of equilibrium is achieved while using the machine, thus preventing a decrease in efficiency. In Physics, mechanical efficiency is the effectiveness of a machine and is defined as \text{Efficiency} = \frac{\text{Mechanical Advantage}}{\text{Velocity
The "screw" does not necessarily need to turn inside the casing, but can be allowed to turn with it in one piece. A screw could be sealed with pitch 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 Nebuchadnezzar II's Hanging Gardens of Babylon. Pitch is the name for any of a number of highly viscous Liquids which appear Solid. Glue or adhesive is a compound that adheres or bonds two items together Bronze is any of a broad range of Copper alloys, usually with Tin as the main additive but sometimes with other elements such as Phosphorus Nebuchadrezzar II, more often called Nebuchadnezzar (c 630-562 BC was a ruler of Babylon in the Chaldean Dynasty, who reigned c Babylon was a City-state of ancient Mesopotamia, the remains of which can be found in present-day Al Hillah, Babil Province, Iraq 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. The History of Greece traditionally encompasses the study of the Greek people, the areas they ruled historically and the territory now composing the modern state of Ancient Rome was a Civilization that grew out of a small agricultural community founded on the Italian Peninsula as early as the 10th century BC
| “ | The design of the everyday Greek and Roman water screw, in contrast to the heavy bronze device of Sennacherib, with its problematic drive chains, has a powerful simplicity. A double or triple helix was built of wood strips (or occasionally bronze sheeting) around a heavy wooden pole. A helix (pl helixes or helices) from the Greek word έλιξ, is a special kind of Space curve, i A cylinder was built around the helices using long, narrow boards fastened to their periphery and waterproofed with pitch | ” |
Along with transferring water to irrigation ditches, this device was also used for "stealing" land from under sea level in the Netherlands and other places in the creation of polders. The Netherlands ( Dutch:, ˈnedərlɑnt is the European part of the Kingdom of the Netherlands, which consists of the Netherlands the Netherlands 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 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 farming. Depending on the length and diameter of the screws, more than one machine could be used to successively lift the same water.
Archimedes' screws are used in sewage treatment plants because they cope well with varying rates of flow and with suspended solids. Sewage treatment, or domestic wastewater treatment, is the process of removing Contaminants from Wastewater, both Runoff ( Effluents An auger in a snow blower or grain elevator is essentially an Archimedes' screw. An auger is a device for moving material or liquid (see Archimedes' screw) by means of a rotating Helical flighting A snow blower, snowblower, or snow thrower is a machine for removing Snow from an area where it is not wanted such as a Driveway, Sidewalk History Grain elevators are a common sight in the grain-growing areas of the world such as the North American Prairies Larger terminal elevators are
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, where it is desirable to minimize the physical handling of fish.
Mathematics behind the screw
The slope of the outside of the screw's helical blades with respect to its sides is 2. This requires that the slope the screw makes with respect to a horizontal line be less than 2 (an angle of 63°) in order for the buckets or pockets of water to form. In the profile of the screw, the projection of each helical blade consists of two sinusoidal curves with the same periods and phases.
One has an amplitude equal to the radius of the outer cylinder and the other has an amplitude equal to the radius of the inner cylinder. The horizontal water level of each full bucket of water is tangent to the inner sinusoidal curve. Thus, if the equation on the inner sinusoidal curve is y = sin x, then the water level is tangent to it at x = arccos(−3/4) = 138. 59°.
- d = diameter of centre tube
- D = diameter of blades
- β = angle of installation
- H0 = civil head
- H1 = difference of medium levels, effective head
- H2 = maximum difference of medium levels, delivery head
- H3 = hydraulic head
- J = number of flights
- L = length of helix
- S = rise
Types
Screw conveyor
A screw conveyor is an Archimedean 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 moulding, 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. Rotary feeders are primarily used for discharge from hoppers/bins receivers and cyclones into a conveying system A variable rate feeder is a piece of industrial control equipment used to deliver solid material at a known rate into some process
Literature
J. Muysken's writings are considered very important, and his methods are still in use. In Germany one of the most common books are by G. Nagel: „Ritz, Handbuch der Wasserförderschnecken“, published in 1968, and „Wasserförderschnecken, Planung, Bau und Betrieb von Wasserhebeanlagen“, by G. Nagel and K. A. Radlik, from 1988. The common author G. Nagel may be a hint that the 2nd book is a revised print run without the name Ritz. Both books discuss the topic very theoretically. They are not available at this moment. At the IFAT 2008 (05th - 09th of May) a new book was introduced. It was written for planners and operators to discuss practical problems and the actual design. It is called „Manual for Archimedean Screw Pump“ by German author P. J. Kantert (Hirthammer Verlag, ISBN: 978-3-88721-202-5). It talks about new developments like energy generating screws and allows a rough calculation of existing screws and an approximately dimensioning of new ones. It is available in German and also in English.
Also See
References
- "Archimedean Screw" by Sándor Kabai, The Wolfram Demonstrations Project, 2007. Archimedes of Syracuse ( Greek:) ( c. 287 BC – c 212 BC was a Greek mathematician, Physicist, Engineer Marcus Vitruvius Pollio (born c 80–70 BC died after c 15 BC was a Roman Writer, Architect and Engineer (possibly praefectus fabrum "Screw propulsion" may also refer to propeller propulsion
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"
raxishandbuch Schneckenpumpe
Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic