This water is then pushed up the tube by the rotating helicoid until it pours out from the top of the tube. As the shaft turns, the bottom end scoops up a volume of water. The screw is usually turned by windmill, manual labor, cattle, or by modern means, such as a motor.

The Archimedes screw consists of a screw (a helical surface surrounding a central cylindrical shaft) inside a hollow pipe. This mechanism quickly replaced the ancient practice of working the pipe by treading. German engineer Konrad Kyeser equipped the Archimedes screw with a crank mechanism in his Bellifortis (1405). It was described by Archimedes, on the occasion of his visit to Egypt, circa 234 BC.Īrchimedes never claimed credit for its invention, but it was attributed to him 200 years later by Diodorus, who believed that Archimedes invented the screw pump in Egypt.ĭepictions of Greek and Roman water screws show them 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 screw pump was later introduced from Egypt to Greece. Some researchers think this device was used to irrigate the Hanging Gardens of Babylon, one of the Seven Wonders of the Ancient World. The reverse screw has the same benefits as using the screw for pumping: it can handle very dirty water and widely varying rates of flow, with high efficiency. It is good for rivers with modest water drops ('low heads'). The turning drives an electric generator, which makes electricity. There is also a kind of reverse Archimedes' screw. The Archimedes screw is still much in use all over the world.

It is not known for certain whether he did invent it, but it is always attributed to him. The screw is often used for filling irrigation ditches.Īrchimedes wrote about it when he was in Alexandria, Egypt. The screw can be turned by hand, or by a windmill, or by an engine. With the bottom end in water, the screw lifts water up to the top, where it pours out of a spout. It is a screw inside a fairly tight-fitting cylinder. It is a type of pump used for raising water up. Archimedes' screw was operated by hand and could raise water efficientlyĪrchimedes' screw is a machine.

Archimedes screw pump design manual