Archimedes Screw
Operation of an Archimedes screw.
An Archimedes screw is a helical gravimetric machine used to lift water, flour, cereals or excavated material. It was invented in the third century a. C. by Archimedes, from which it receives its name, although there is hypothesis that it was already used in Ancient Egypt. It is based on a screw that is rotated inside a hollow cylinder, located on an inclined plane, and that allows raising the body or fluid located below the axis of rotation. From its invention until now it has been used for pumping. It is also called an endless screw because of its infinite circuit.
The Archimedes screw consists of a screw ("helical surface that surrounds a cylinder") inside a tube. The movement of this device is achieved thanks to a mill or manual work. Because the screw rotates, it causes the liquid underneath to ascend through the helical surface that surrounds it. It was used mainly for irrigation systems and to draw water from mines or other inaccessible sites.
Besides its use in the systems of addition of its use in the systems of watered, it was used for the recovery of earth in the Netherlands among others. The land of the sea is obtained and the water that it brings is pumped out of the closed area, beginning the process of draining the land for its use in agriculture.
The Archimedes screw was also used by John Burland, floor engineer, in 2001 to stabilize the tower of Pisa. Small amounts of subsoil saturated with water were removed below the northern part of the tower. In this way his inclination was corrected.
It is used in wastewater treatment plants, since they must deal with different flow rates and with suspended solids. They make use of it devices such as snow blowers or grain elevators. We find the same principle applied in fish farms, where they use them to lift the fish safely and transport them to another site. In this way the physical handling of the fish is avoided.
Not only serves to transport water, but also bodies, as we see in the image (above), in which a marble is transported. It is used especially to transport grains in silos systems.
