The Archimedes Screw, Archimedean Screw or Screwpump.
The Archimedes screw is one of the oldest machines still in use today, it's a device for lifting water. It's been used for thousands of years to help irrigate crops, as an example, an excert from the writings of Diodorus Siculus, a Greek historian from around circa first century BC writes;
Men can easily irrigate the land by means of a certain instrument conceived by Archimedes of Syracuse, which gets its name because it has the form of a spiral or screw.
The Archimedes Screw, also reffered to as the Archimedean Screw or Screwpump, as it may well be referenced by any of these names, is a simple machine originally invented to facillatate raising water from a low river or dyke into higher irrigation ditches.
Although being a waterpump, it has also been sucessfully put to other uses where water needs lifting, an example of which is the writings from Athenaeus of Naucratis, a Greek historian, circa A.D. 200;
The bilge-water, even when it became very deep, could easily be pumped out by one man with the aid of the screw, an invention of Archimedes.
This is one of several inventions more often than not, has traditionally been credited to the inventor Archimedes of Syracuse, around the third century B.C. (circa 287-212 BC).
The Archimedean Screwpump consists of a helical screw inside a hollow tube, the whole thing would then be turned on its axis either by man power, donkey power or a windmill or sorts. The bottom end would be submerged and as it turns would scoop up an amount of water.
The scooped water will then climb up the inside of the tube within the spiral as the whole tube and helical is turned, eventuallly releasing the water at the top end into another higher irrigation ditch feeding the watering system.
Quite often the outer edge of the helical and the inner surface of the cylinder did not need even seal perfectly water-tight. But because the relatively large amount of water which was scooped on each rotation of the device coupled with the rotational speed of operation, it didn't matter much. Any leaked water within just drain down into the next section below.
The machine proved to be quite good at lifting water despite of these slight flaws as a cylinder containing the helical could be made fairly large. Several feet in diameter would not be uncommon and an Archimedean Screw of this size could move alot of water just by being rotated by one person running on the surface of the cylinder.
Quite a few years ago now manufacturer Ritz Atro discovered another use for the screw. By reversing the process so that the weight of the water turns the screw electricity can be generated.
It works in exactly the same way as a traditional generator turned by an engine. Instead of the generator being turned by the engine. It's being turned by the Archemedes Screw and the screw is being turned by the water.
The screw or screws are installed alongside a dam or river weir. The water is diverted from the top of the dam or weir to run downhill through the screws and back into the river.
Archimedean screws have a long life span, due to their simple nature of construction, of around 40 years and are ideal for sites with a low head of water. Whether lifting water or generating electricity.
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