In the Netherlands, Archimedes' Screws were used to remove water from polders to create dry land areas below sea level. In such large-scale applications, more than one screw is used to pump water from a single source. Today, Archimedes' Screws sill operate on the Nile delta for irrigation purposes.

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Archimedes' Screw

A cross-section of a simplified Archimedes Screw: As the screw turns, water is drawn up through the system and released at the top of the pump.

When the lower end is semi-submerged in water (and the entire device is sitting at an angle of roughly 45°) and the screw is turned - either by windmill or manual labour - it draws a small volume of water into the spiral chamber, and with each revolution of the screw raises the water above the next thread and so on, until it reaches the upper end of the device, while more water is drawn in at the bottom. Once at the top, the water can be pumped into irrigation channels or fed into pipelines, depending on the application.

The ancient Greeks and Romans constructed these machines by arranging and fixing wooden strips in a double or triple helix form, centred on a heavy wooden pole. The encasing cylinder was made of long wooden planks and made somewhat waterproof with pitch - a resinous, waterproof, sticky, dark-coloured substance that is produced when tar or turpentine is distilled.

Light, loose solid materials can also be lifted in the Archimedes Screw and, hence, the device has various applications in modern mills and factories where volumes of grains and sand need to be lifted. These screws are also employed in sewage works, and devices using a similar principle are known in places that receive a lot of snow, in the form of augers in snow blowers. In the Netherlands, Archimedes' Screws were used to remove water from polders to create dry land areas below sea level. In such large-scale applications, more than one screw is used to pump water from a single source. Today, Archimedes' Screws sill operate on the Nile delta for irrigation purposes.

The machine shows some advanced technological creativity and expertise, even for the era from which it came, as it was known that the screw did not have to fit very tightly inside the cylinder in order for the machine to work: If water leaked out from a thread in the screw, it would simply fall back down to the previous thread. Considering the volumes of water that are typically transported in an Archimedes' screw in relation to the angular speed of the screw, an equilibrium was achieved which made the machine a constantly efficient device. Read more at myfundi.co.za

 

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