Sakia

This article is about the water pump. For article of Byzantine clothing known as the tablion (plural tablia), see Byzantine dress.
The "Persian wheel", c. 1905

A sakia, alternative spelling sakieh or saqiya (from Arabic: ساقية‎, sāqīya), also called Persian wheel, tablia and in Latin tympanum[1] is a mechanical water lifting device which uses buckets, jars, or scoops fastened either directly to a vertical wheel, or to an endless belt activated by such a wheel. The vertical wheel is itself attached by a drive shaft to a horizontal wheel, which is traditionally set in motion by animal power. Because it is not using the power of flowing water, the sakia is different from a noria and any other type of water-wheel. It is still used in India, Egypt and other parts of the Middle East, and in the Iberian Peninsula and the Balearic Islands. It may have been invented in Hellenistic Egypt, Persia or India.

Description; performance

- With buckets directly on the wheel -

The sakia is a large hollow wheel, traditionally made of wood. One type has its clay pots or buckets attached directly to the periphery of the wheel, which limits the depth it can scoop water from to less than half its diametre. The modern version is normally made of galvanized sheet steel and consists of a series of scoops. The modern type dispenses the water near the hub rather than from the top, the opposite of the traditional types. It is a method of irrigation frequently met within various parts of the Indian subcontinent. Sakia wheels range in diameter from two to five metres. Though traditionally driven by draught animals, they are now increasingly attached to an engine. While animal-driven sakias can rotate at 2–4 rpm, motorised ones can make as much as 8–15 rpm. The improved modern versions are also known as zawaffa and jhallan.

Schematics of an ideal modern sakia (Fathi model; drawing by FAO)
- With buckets attached to endless belt -

The historical Middle-Eastern device known in Arabic as saqiya usually had its buckets attached to a double chain, creating a so-called "pot garland". This allowed scooping water out of a much deeper well.

An animal-driven sakia can raise water from 10-20 metres depth, and is thus considerably more efficient than a swape or shadoof, as it is known in Arabic, which can only pump water from 3 metres.

"Sakia"/"saqiya" versus "noria"

The terms referring to traditional as well as modern water-raising devices used in the Middle East, India, Spain and other areas are sometimes used rather loosely. One clear distinction though is important. The term noria is commonly used for devices using the power of moving water. For devices powered by animals, the usual term is sakia or saqiya. The term "water-wheel" is reserved, by definition, to wheels powered by flowing water, and should not be used for sakia wheels which are only lifting the water, but are not powered by it. Other types of similar devices are grouped under the name of chain pumps. In Spain the term "noria" is used also for some devices which are actually sakias.

A sakia or saqiya differs from a noria in two substantial ways. First, by the way it is powered, namely by animal power or rarely by wind, in modern versions also by engines, but never by hydropower. The other difference is that a saqiya is lifting the water out of a well or a body of standing water, while the noria is placed on the bank of a river.

The noria uses the water power obtained from the flow of a river. The noria consists of a large, very narrow undershot water-wheel, whose rim is made up of a series of containers which lift water from the river to a very small aqueduct at the top of the wheel. In this it is very similar to the one type of sakia without a pot-garland, with the posts mounted directly on the wheel, thus the widespread confusion.

A few historic norias were hybrids, consisting of waterwheels assisted secondarily by animal power.

In Spanish an animal-driven sakia is named aceña, with the exception of the Cartagena area, where it is called a noria de sangre, or "waterwheel of blood". Another, much rarer type of sakia uses the same system, of a necklace of clay or wooden buckets, but it is driven by the wind. The wind-driven sakias in the vicinity of Cartagena are virtually identical in appearance with the local grinding mills.

Types

There are two main types of sakia. One type consist of a vertical wheel which is slung with an endless belt or chain of buckets. The buckets hang down into a well which may be up to 8 m (26 ft) deep.

The second type has the buckets or other water containers attached directly to the vertical wheel.

The most primitive sakias are driven by donkeys, mules, or oxen. The animal turns a horizontal wheel, which is engaged with the vertical wheel and so causes it to turn. This causes the buckets of the first type to circulate and lift up water from a deeper well, or with the second type, it causes the vertical wheel to rotate and scoop up water from a less deep well.

In Spanish an animal-driven sakia is named aceña, with the exception of the Cartagena area, where it is called a noria de sangre, or "waterwheel of blood".

In terms of propulsion, there is a different, much rarer type of sakia which uses the same general technique, but it is driven by wind. The wind-driven sakias in the vicinity of Cartagena, Spain, are virtually identical in appearance with the local grinding mills.

History

In India

The sakia is, according to some, invented in India, where the earliest reference to it is found in the panchatantras (c. 3rd century BC) where it was known as an "araghatta";[2] which is a combination or the words "ara" (speedy or a spoked[wheel]) and "ghattam" (pot)[3] in Sanskrit. That device was either used like a sakia, to lift water from a well while being powered by oxen or people, or it was used to irrigate fields when it was powered in the manner of a water-wheel by being placed in a stream or large irrigation channel. In the latter case we usually speak of a "noria" as opposed to a "sakia".[4]

In Hellenistic Egypt

The earliest Mediterranean evidence of a sakia is from a Hellenistic tomb painting in Ptolemaic Egypt which dates to the 2nd century BC. It shows a pair of yoked oxen driving a compartmented waterwheel. The Hellenistic sakia gear system is already shown fully developed to the point that "modern Egyptian devices are virtually identical".[5] It is assumed that the scientists of the Museum of Alexandria, at the time the most active Greek research center, may have been involved in its implementation.[6] An episode from the Alexandrian War in 48 BC tells of how Caesar's enemies employed geared waterwheels to pour sea water from elevated places on the position of the trapped Romans.[7]

Medieval Islamic realm

Al-Jazari's advanced saqiya, both animal- and water-wheel-driven (1206).

A manuscript by Al-Jazari featured an intricate device based on a saqiya, powered in part by the pull of an ox walking on the roof of an upper-level reservoir, but also by water falling onto the spoon-shaped pallets of a water-wheel placed in a lower-level reservoir.[8]

Complex saqiyas consisting of more than 200 separate components were used extensively by Muslim inventors and engineers in the medieval Islamic world.[9] The mechanical flywheel, used to smooth out the delivery of power from a driving device to a driven machine and, essentially, to allow lifting water from far greater depths (up to 200 metres), was first employed by Ibn Bassal (fl. 1038–1075), of Islamic Spain.[10]

The first known use of a crankshaft in a saqiya was featured in another one of al-Jazari's machines.[11] The concept of minimising the intermittence is also first implied in one of al-Jazari's saqiya devices, which was to maximise the efficiency of the saqiya.[11] Al-Jazari also constructed a water-raising device that was run by hydropower, though the Chinese had been using hydropower for the same purpose before him. Animal-powered saqiyas and water-powered norias similar to the ones he described have been supplying water in Damascus since the 13th century,[12] and were in everyday use throughout the medieval Islamic world.[11]

See also

Notes

  1. ↑ Water lifting devices book description
  2. ↑ http://base.d-p-h.info/en/fiches/dph/fiche-dph-7866.html
  3. ↑ http://spokensanskrit.de/index.php?script=HK&beginning=0+&tinput=+ara&trans=Translate&direction=AU
  4. ↑ https://rainwaterharvesting.wordpress.com/2008/02/23/the-persian-wheel-revisited-araghatta/
  5. ↑ Oleson 2000, pp. 234, 270
  6. ↑ Oleson 2000, pp. 271f.
  7. ↑ Oleson 2000, p. 271
  8. ↑ Needham, Volume 4, Part 2, p. 353.
  9. ↑ Donald Routledge Hill (1996), "Engineering", in Roshdi Rashed, Encyclopedia of the History of Arabic Science, Vol. 3, pp. 751–795 [771].
  10. ↑ Ahmad Y Hassan, Flywheel Effect for a Saqiya, History of Science and Technology in Islam
  11. ↑ 11.0 11.1 11.2 Donald Routledge Hill, "Engineering", p. 776, in Roshdi Rashed, ed., Encyclopedia of the History of Arabic Science, Vol. 2, pp. 751–795, Routledge, London and New York
  12. ↑ Ahmad Y Hassan, Al-Jazari and the History of the Water Clock

References

Further reading

External links