ARCHIMEDES-SCREW.pptx

Renewable Energy Topic

1. ANGLES

2. Archimedes screw, machine for raising water, allegedly invented by the ancient Greek scientist Archimedes for removing water from the hold of a large ship. One form consists of a circular pipe enclosing a helix and inclined at an angle of about 45 degrees to the horizontal with its lower end dipped in the water; rotation of the device causes the water to rise in the pipe.

3. Design The Archimedes screw consists of a screw 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.

4. Uses The  main application  of the screw throughout history was to  transport water  to irrigation systems and for dewatering mines or other low-lying areas.

5. How does Archimedes screw generate electricity? When used as a hydro turbine the principle is the same but acts in reverse. The water enters the screw at the top and the weight of the water pushes on the helical flights, allowing the water to fall to the lower level and causing the screw to rotate. This rotational energy can then be extracted by an electrical generator connected to the main shaft of the screw. This makes Archimedean screws an alternative model for generating hydroelectric power – typically called screw turbines or Archimedean turbines.