Archimedes' screw a crank mechanism in his "Bellifortis" (1405). This mechanism quickly replaced the ancient practice of working the pipe by treading. The Archimedes screw consists of a screw (a helical surface surrounding a central cylindrical shaft) inside a hollow pipe. The screw is usually turned by windmill, manual labor, cattle, or by modern means, such as a motor. As the shaft turns the bottom end scoops up a volume of water. This water is then pushed up the tube by the rotating helicoid until it pours out from the top of the tube. The contact surface between the screw and the
Archimedes' screw areas. It was used for draining land that was underneath the sea in the Netherlands and other places in the creation of polders. Archimedes screws are used in sewage treatment plants because they cope well with varying rates of flow and with suspended solids. An auger in a snow blower or grain elevator is essentially an Archimedes screw. Many forms of axial flow pump basically contain an Archimedes screw. The principle is also found in pescalators, which are Archimedes screws designed to lift fish safely from ponds and transport them to another location. This technology is used primarily at fish