Difference between revisions of "Archimedes Screws"

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* Designed to lift fish safely from ponds, Desirable to minimize the physical handling of fish
* Designed to lift fish safely from ponds, Desirable to minimize the physical handling of fish
* Depending on the length and diameter of the screws, more than one machine could be used successively to lift the same water
* Depending on the length and diameter of the screws, more than one machine could be used successively to lift the same water
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==Working principle==
An analysis, using the lifting of marbles instead of water, is used in almost all nineteenth century texts. The lower end of the helical tube dips into a dish of marbles and scoops one up. The helix continues to revolve, and the marble is continually being lifted a short distance up an inclined plane. The frictional forces are small, and the marble keeps rolling down an infinite succession of inclined planes formed by the revolving helix. At the same time the marble resides at the local low spot on the helix, and is carried up the slope by forces perpendicular to its local motion.
An analysis, using the lifting of marbles instead of water, is used in almost all nineteenth century texts. The lower end of the helical tube dips into a dish of marbles and scoops one up. The helix continues to revolve, and the marble is continually being lifted a short distance up an inclined plane. The frictional forces are small, and the marble keeps rolling down an infinite succession of inclined planes formed by the revolving helix. At the same time the marble resides at the local low spot on the helix, and is carried up the slope by forces perpendicular to its local motion.
==Video==
<youtube>X-oo11B1a7Y </youtube>