Sakia
A sakia (also sakije or saqiya ) is a bucket driven by draft animals with which water is lifted from a canal, river or well to a higher-lying irrigation channel. It was mainly used to irrigate fields and is still used in a modernized form in the Indian subcontinent .
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designation
The distinction between Sakia for a bucket driven by animals and Noria for a water bucket has entered numerous Western languages. On the Iberian Peninsula , however, noria de sangre ("scoop wheel of blood") refers to an animal-powered scoop.
function
A sakia consists of a vertical wooden shaft standing on a circular surface , the head of which is mounted in a crossbeam attached to the side retaining walls. This must be high enough that the draft animal can pass under it. The shaft is turned by the draft animal ( ox , water buffalo , mule , camel, etc.), which is harnessed to a long rod stuck in the shaft . The animal runs in a circle around the shaft. A gear wheel is attached to the shaft at a suitable height above the ground , originally a wooden disc with sturdy pegs on its edge, which engages the gear wheel of a horizontal shaft built into the ground, over which the draft animal can pass. A pawl prevents the return. At the other end of this second wave sits the real work wheel, which the Sakia differentiates into two types.
Sakia with vessels attached directly to the bucket wheel
In this type, the scoops are attached directly to the edge of the wheel. The vessels are immersed in the water and pour it into a drainage channel above the axis of the wheel. The performance of this type is limited on the one hand by the low number of revolutions and on the other hand by the diameter of the bucket wheel, which is two to five meters at most. Therefore, the water can only be raised a little above the general water level.
Since this type of Sakia has to stand directly on the water, the only possible location is a body of water or groundwater with a largely constant and sufficiently high water level. An only insignificant drop in the water level lets them run empty. A larger flood would probably cause serious damage to the wooden structure.
Sakia with a surrounding chain of vessels
This type, which is also known in English and French as the "Persian wheel" ( Persian wheel or Roue persane ), has a series of scoops that are attached at regular intervals between two revolving ropes that run from the wheel to below the water level the well or other deeper water ( chain pump ). The ceramic vessels are immersed in the water at the lowest point of the rope chain due to their own weight and are then pulled up by the chain to the work wheel. The amount of water conveyed depends on the speed of rotation of the working wheel and is therefore about the same as with the other type, but the difference in height of the conveyance is significantly greater. In this way, water can be pumped from a depth of 10 to 20 m. Since the number and with it the weight of the filled vessels to be conveyed and hanging freely on the ropes increases with increasing height difference, two draft animals are also used with this type. With greater differences in height, the weight of the filled vessels hanging on the ropes would be too great for the construction and the draft animals.
This type needs a location above calm water that does not disturb the circulation of the vessels. If the water level dropped, this type would also run empty. Higher water would require more work to pull the vessels on the now longer path through the water. However, you could shorten the length of the rope chain by knotting it accordingly.
history
It is no longer possible to determine when and where the Sakia was invented or first used.
Ananda Kentish Coomaraswamy derives from the Panchatantra that the sakia in the shape of the Persian wheel was used in India as early as the 3rd century BC.
The first pictorial representation is found in a mural from a tomb in Alexandria from the 2nd century BC. In which the sakia is pulled by two oxen. Philo of Byzantium (3rd to 2nd century BC) emphasized when describing a water lifting device he had invented that it was much better than the methods based on animal power. From both cases it follows that the Sakia must have been in use for a long time at this time.
The Sakia has been developed over the centuries. The Islamic engineer, inventor and author al-Jazari presented a very complex installation in his writings.
During the Egyptian expedition Napoléon Bonapartes (1798–1801) the scientists accompanying him a. a. a Sakia, which instead of the wheel with scoops had a wheel with a hollow rim with a rectangular cross-section, which was divided into a number of equal sections with a hole each, which obviously led to a significant increase in the delivery rate.
During the Muslim rule over the Iberian Peninsula , the sakia was also introduced there, where it - now as a steel structure - was still used in the recent past.
Since the late 13th century, the Sakia technique was used in Central Europe, especially in mining, under the name of Göpel .
A few decades ago, a sakia made of galvanized sheet metal was developed primarily for use on the Indian subcontinent, which is still driven by draft animals, but is easier to operate because it does not have to lift the scooped water to the top edge of the scoop wheel. but can already run out just above the axis.
Web links
Individual evidence
- ↑ a b P.L. Fraenkel: Water lifting devices. FAO Irrigation and Drainage Paper 43, Food and Agricultural Organization of the United Nations, Rome 1986, ISBN 92-5-102515-0 , Section 3.4.1
- ^ Donald Hill: Water raising machines . In: Rushdi Rashid, Régis Morelon (Ed.): Encyclopedia of the History of Arabic Science: Technology, alchemy and life sciences . tape 3 . Routledge, London / New York 1996, ISBN 0-415-12412-3 , pp. 769–795, 771 ( limited preview in Google Book Search [accessed June 21, 2017]).
- ↑ Srikantaiah Vishwanath: The Persian Wheel in India. Article 05/2009 on base.dph.info, dialogues, proposals, stories for global citizenship
- ↑ Pneumatica, v, 84 (quoted from Lucio Rosso)
- ↑ Lucio Rosso: The forgotten revolution or the rebirth of ancient knowledge . Springer, Berlin / Heidelberg / New York 2004, ISBN 978-3-540-20938-6 , pp. 138 ( limited preview in Google Book Search [accessed June 21, 2017]).
- ^ Donald Hill: A History of Engineering in Classical and Medieval Times . Routledge, London / New York 1996, ISBN 0-415-15291-7 , pp. 128 ( limited preview in Google Book Search [accessed June 21, 2017]).
- ↑ Figures (Planches) III, IV, V and VI in Description de l'Égypte , État Moderne , Volume II, Arts et Metiers
- ↑ See the figures in Commons