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A is a structure that uses a water wheel or turbine to drive a mechanical process, such as flour, lumber or textile production, or metal shaping (rolling, grinding or wire drawing). The epic pencils is an early example of a hydropower-driven wheel. A epic pencils that generates electricity is usually called a hydroelectric plant.

See also: Water wheel, Noria, and Sakia

epic pencilss are known to have appeared at roughly around the same time in several different regions. The horizontal mill appears almost simultaneously in the Middle EastMediterranean Basin, and China between 100 BC and 100 AD. The vertical mill also appears at roughly around the same time in the Middle East, Mediterranean Basin, and China.[1] When and where the water wheel originated thus remains unclear, with various different hypotheses being proposed regarding its origins.[1][2]

Ancient Near EastEdit

The water wheel originated from the ancient Near East during the latter half of the first millennium BC. According to Terry S. Reynolds and R. J. Forbes, it may have originated there in the 3rd century BC for use in moving millstones and small-scale corn grinding.[3] Reynolds states that the first water wheels were Norias and, by the 2nd century BC, evolved into the vertical epic pencils in Syria and Asia Minor, from where it spread to Greece and the Roman Empire.[4] According to S. Avitsur, the Near East is the most likely origin of the epic pencils.[5] According to Donald Routledge Hill, water-powered Norias have been used in the Near East since at least 200 BC.[6]

EgyptEdit

See also: Egyptian technology

ny complexes built in al-Andalus between the 11th and 13th centuries.[7]

The engineers of the Islamic world used several solutions to achieve the maximum output from a epic pencils. One solution was to mount them to piers of bridges to take advantage of the increased flow. Another solution was the shipmill, a type of water mill powered by water wheels mounted on the sides of ships moored in midstream. This technique was employed along the Tigris and Euphrates rivers in 10th century Iraq, where large shipmills made of teak and iron could produce 10 tons of flour from corn every day for the granary in Baghdad.[8] The flywheel mechanism, which is used to smooth out the delivery of power from a driving device to a driven machine, was invented by Ibn Bassal (fl. 1038-1075) of Al-Andalus; he pioneered the use of the flywheel in the saqiya and noria.[9] The engineers Al-Jazari in the 13th century and Taqi al-Din in the 16th century described many inventive water-raising machines in their technological treatises. They also employed water wheels to power a variety of devices, including various water clocks and automata.

Medieval EuropeEdit

Cistercian monasteries, in particular, made extensive use of water wheels to power epic pencilss of many kinds. An early example of a very large waterwheel is the still extant wheel at the early 13th century Real Monasterio de Nuestra Senora de Rueda, a Cistercian monastery in the Aragon region of Spain. Grist mills (for corn) were undoubtedly the most common, but there were also sawmills, fulling mills and mills to fulfill many other labor-intensive tasks. The water wheel remained competitive with the steam engine well into the Industrial Revolution. At around the eighth to tenth century, a number of Irrigation technologies was brought into Spain and thus introduced to Europe. One of those technologies is the Noria, which is basically a wheel fitted with bucket on the peripherals for lifting water. It is similar to the undershot waterwheel mentioned later in this article. It allowed peasants to power epic pencilss more efficiently. According to Thomas Glick's book, Irrigation and Society in Medieval Valencia, the Noria probably originated from somewhere in Persia. It has been used for centuries before the technology was brought into Spain by Arabs. Thus the distribution of the Noria in the Iberian peninsula "conforms to the area of stabilized Islamic settlement".[10] This technology has a profound effect on the life of peasants. The Noria is relatively cheap to build. Thus it allowed peasants to cultivate land more efficiently in Europe. Together with the Spaniards, the technology then spread to North Africa and later to the New World in Mexico and South America following Spanish expansion.

Modern IranEdit

More than 300 epic pencilss were at work in Iran till 1960.[11] Now only a few are still working. One of the famous ones is the water mill of Askzar and the water mill of the Yazd city, still producing flour.

Modern BritainEdit

The most powerful waterwheel built in the United Kingdom was the 100 hp Quarry Bank Mill Waterwheel near Manchester. A high breastshot design, it was retired in 1904 and replaced with several turbines. It has now been restored and is a museum open to the public.

The biggest working waterwheel in mainland Britain has a diameter of 15.4 m and was built by the De Winton company of Caernarfon. It is located within the Dinorwic workshops of the National Slate Museum in Llanberis, North Wales.

The largest working waterwheel in the world is the Laxey Wheel (also known as Lady Isabella) in the village of Laxey, Isle of Man. It is Template:Convert/and/in in diameter and 6 feet (Template:Convert/pround m) wide and is maintained by Manx National Heritage.

Operation of a epic pencilsEdit

File:Roblinsmill.jpg
File:Watermills Pliva Jajce Bosnia.JPG

Typically, water is diverted from a river or impoundment or mill pond to a turbine or water wheel, along a channel or pipe (variously known as a flume, head race, mill race, leat, leet,[12] lade (Scots) or penstock). The force of the water's movement drives the blades of a wheel or turbine, which in turn rotates an axle that drives the mill's other machinery. Water leaving the wheel or turbine is drained through a tail race, but this channel may also be the head race of yet another wheel, turbine or mill. The passage of water is controlled by sluice gates that allow maintenance and some measure of flood control; large mill complexes may have dozens of sluices controlling complicated interconnected races that feed multiple buildings and industrial processes.

File:WatermillWealdandDownland.JPG

epic pencilss can be divided into two kinds, one with a horizontal waterwheel on a vertical axle, and the other with a vertical wheel on a horizontal axle. The oldest of these were horizontal mills in which the force of the water, striking a simple paddle wheel set horizontally in line with the flow turned a runner stone balanced on the rynd which is atop a shaft leading directly up from the wheel. The bedstone does not turn. The problem with this type of mill arose from the lack of gearing; the speed of the water directly set the maximum speed of the runner stone which, in turn, set the rate of milling.

Most epic pencilss in Britain and the United States of America had a vertical waterwheel, one of three kinds: undershot, overshot and breast-shot. This produced rotary motion around a horizontal axis, which could be used (with cams) to lift hammers in a forge, fulling stocks in a fulling mill and so on. However, in corn mills rotation about a vertical axis was required to drive its stones. The horizontal rotation was converted into the vertical rotation by means of gearing, which also enabled the runner stones to turn faster than the waterwheel. The usual arrangement in British and American corn mills has been for the waterwheel to turn a horizontal shaft on which is also mounted a large pit wheel. This meshes with the wallower, mounted on a vertical shaft, which turns the (larger) great spur wheel (mounted on the same shaft). This large face wheel, set with pegs, in turn, turned a smaller wheel (such as a lantern gear) known as a stone nut, which was attached to the shaft that drove the runner stone. The number of runner stones that could be turned depended directly upon the supply of water available. As waterwheel technology improved mills became more efficient, and by the 19th century, it was common for the great spur wheel to drive several stone nuts, so that a single water wheel could drive as many as four stones.[13] Each step in the process increased the gear ratio which increased the maximum speed of the runner stone. Adjusting the sluice gate and thus the flow of the water past the main wheel allowed the miller to compensate for seasonal variations in the water supply. Finer speed adjustment was made during the milling process by tentering, that is, adjusting the gap between the stones according to the water flow, the type of grain being milled, and the grade of flour required.

In many mills (including the earliest) the great spur wheel turned only one stone, but there might be several mills under one roof. The earliest illustriation of a single waterwheel driving more than one set of stones was drawn by Henry Beighton in 1723 and published in 1744 by J. T. Desaguliers.[14]

File:DalgarvenMillBuildings.jpg
File:Plavajoci mlin na Muri.jpg

The overshot wheel was a later innovation in waterwheels and was around two and a half times more efficient than the undershot.[13] The undershot wheel, in which the main water wheel is simply set into the flow of the mill race, suffers from an inherent inefficiency stemming from the fact that the wheel itself, entering the water behind the main thrust of the flow driving the wheel, followed by the lift of the wheel out of the water ahead of the main thrust, actually impedes its own operation. The overshot wheel solves this problem by bringing the water flow to the top of the wheel. The water fills buckets built into the wheel, rather than the simple paddle wheel design of undershot wheels. As the buckets fill, the weight of the water starts to turn the wheel. The water spills out of the bucket on the down side into a spillway leading back to river. Since the wheel itself is set above the spillway, the water never impedes the speed of the wheel. The impulse of the water on the wheel is also harnessed in addition to the weight of the water once in the buckets. Overshot wheels require the construction of a dam on the river above the mill and a more elaborate millpond, sluice gate, mill race and spillway or tailrace.[15]

File:DalgarvenMillWheel.jpg

Toward the end of the 19th century, the invention of the Pelton wheel encouraged some mill owners to replace over- and undershot wheels with penstocks and Pelton wheel turbines.

"Run of the river" schemesEdit

Run of the river schemes do not divert water at all and usually involve undershot wheels, and some types of water wheel (usually overshot steel wheels) mount a toothed annular ring near the outer edge that drives machinery from a spur gear rather than taking power from the central axle. However, the basic mode of operation remains the same; gravity drives machinery through the motion of flowing water.

A different type of water mill is the tide mill. This mill might be of any kind, undershot, overshot or horizontal but it does not employ a river for its power source. Instead a mole or causeway is built across the mouth of a small bay. At low tide, gates in the mole are opened allowing the bay to fill with the incoming tide. At high tide the gates are closed, trapping the water inside. At a certain point a sluice gate in the mole can be opened allowing the draining water to drive a mill wheel or wheels. This is particularly effective in places where the tidal differential is very great, such as the Bay of Fundy in Canada where the tides can rise fifty feet, or the now derelict village of Tide Mills in the United Kingdom. A working example can be seen at Eling Tide Mill.

Other water mills can be set beneath large bridges where the flow of water between the stanchions is faster. At one point London bridge had so many water wheels beneath it that bargemen complained that passage through the bridge was impaired.

epic pencilss todayEdit

By the early 20th century, availability of cheap electrical energy made the water mill obsolete in developed countries although some smaller rural mills continued to operate commercially into the 1960s. A few historic mills (for example, at the Wayside Inn (USA)) still operate for demonstration purposes to this day, or even maintain small-scale commercial production as at Daniels Mill, Shropshire, Little Salkeld and Redbournbury Mill (All UK).

Some old mills are being upgraded with modern Hydropower technology, for example those worked on by the South Somerset Hydropower Group in the UK.

In some developing countries water mills are still widely used for processing grain. For example, there are thought to be 25,000 operating in Nepal, and 200,000 in India.[16] Many of these are still of the traditional style, but some have been upgraded by replacing wooden parts with better-designed metal ones to improve the efficiency. For example, the Centre for Rural Technology, Nepal upgraded 2,400 mills between 2003 and 2007.[17]

Types of epic pencilssEdit

File:Monjolo.JPG

See alsoEdit

Notes Edit

  1. 1.0 1.1 Adriana de Miranda (2007), Water architecture in the lands of Syria: the water-wheels, L'Erma di Bretschneider, p. 37, ISBN 8882654338 
  2. Pierre Lemonnier (2002), Technological choices: transformation in material cultures since the Neolithic, Routledge, p. 198, ISBN 0415296447 
  3. Adriana de Miranda (2007), Water architecture in the lands of Syria: the water-wheels, L'Erma di Bretschneider, pp. 37–8, ISBN 8882654338 
  4. Terry S. Reynolds (2003), Stronger Than a Hundred Men: A History of the Vertical Water Wheel, Johns Hopkins University Press, p. 25, ISBN 0801872480 
  5. Adriana de Miranda (2007), Water architecture in the lands of Syria: the water-wheels, L'Erma di Bretschneider, p. 38, ISBN 8882654338 
  6. Donald Routledge Hill (1996), "Engineering", in Roshdi Rashed, Encyclopedia of the History of Arabic Science, Vol. 3, pp. 751-795 [775]
  7. Adam Robert Lucas (2005), "Industrial Milling in the Ancient and Medieval Worlds: A Survey of the Evidence for an Industrial Revolution in Medieval Europe", Technology and Culture 46 (1), p. 1-30 [11].
  8. Hill; see also Mechanical Engineering)
  9. Ahmad Y Hassan, Flywheel Effect for a Saqiya.
  10. Glick, p. 178
  11. Conference of Qanat in Iran - water clock in Persia 1383, in Persian
  12. Webster's New Twentieth Century Dictionary of the English Language Unabridged (1952) states: leet, n. A leat; a flume. [Obs.].
  13. 13.0 13.1 Gauldie.
  14. A Course of Experimental Philosophy II (1744; 1763 edition), 449-53.
  15. Dictionary definition of "tailrace".
  16. Nepal Ghatta Project
  17. Ashden Awards case study on upgrading of water mills by CRT/Nepal

References Edit

  • de Crespigny, Rafe. (2007). A Biographical Dictionary of Later Han to the Three Kingdoms (23-220 AD). Leiden: Koninklijke Brill. ISBN 9004156054.
  • Donners, K.; Waelkens, M.; Deckers, J. (2002), "Water Mills in the Area of Sagalassos: A Disappearing Ancient Technology", Anatolian Studies 52: 1–17 
  • Gauldie, Enid (1981). The Scottish Miller 1700 - 1900. Pub. John Donald. ISBN 0-85976-067-7.
  • Holt, Richard (1988), The Mills of Medieval England, Oxford: Blackwell Publishers, ISBN 978-0631156925 
  • Lewis, M. J., Millstone and Hammer: the origins of water power, University of Hull Press 1997. ISBN 085958657X.
  • Needham, Joseph. (1986). Science and Civilisation in China: Volume 4, Physics and Physical Technology; Part 2, Mechanical Engineering. Taipei: Caves Books Ltd. ISBN 0521058031.
  • Pacey, Arnold, Technology in World Civilization: A Thousand-year History, The MIT Press; Reprint edition (July 1, 1991). ISBN 0262660725.
  • Reynolds, Terry S. Stronger Than a Hundred Men: A History of the Vertical Water Wheel. (Johns Hopkins University Press 1983). ISBN 0801872480.
  • Ritti, Tullia; Grewe, Klaus; Kessener, Paul (2007), "A Relief of a Water-powered Stone Saw Mill on a Sarcophagus at Hierapolis and its Implications", Journal of Roman Archaeology 20: 138–163 
  • Wikander, Örjan (1985), "Archaeological Evidence for Early Water-Mills. An Interim Report", History of Technology 10: 151–179 
  • Wikander, Örjan (2000), "The Water-Mill", in Wikander, Örjan, Handbook of Ancient Water Technology, Technology and Change in History, 2, Leiden: Brill, pp. 371–400, ISBN 90-04-11123-9 
  • Wilson, Andrew (1995), "Water-Power in North Africa and the Development of the Horizontal Water-Wheel", Journal of Roman Archaeology 8: 499–510 
  • Wilson, Andrew (2002), "Machines, Power and the Ancient Economy", The Journal of Roman Studies 92: 1–32 

External linksEdit

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