Screw Turbine Working and benefits

 Screw Turbine

The screw turbine is a water turbine which uses the principle of the Archimedean screw to convert the potential energy of water on an upstream level into work. Water flows into the turbine and its weight presses down onto the blades of the turbine, which in turn forces the turbine to turn. 

Working of Screw Turbine

The turbine consists of a rotor in the shape of an Archimedean screw which rotates in a semicircular trough. Water flows into the turbine and its weight presses down onto the blades of the turbine, which in turn forces the turbine to turn. Water flows freely off the end of the turbine into the river. The upper end of the screw is connected to a generator through a gearbox. The Archimedean screw turbine is applied on rivers with a relatively low head (from 0.1 m to 10 m) and on low flows (0.01 m³/s up to around 10 m³/s on one turbine). Due to the construction and slow movement of the blades of the turbine, the turbine is considered to be friendly to aquatic wildlife. It is often labelled as "fish friendly". The Archimedean turbine may be used in situations where there is a stipulation for the preservation and care of the environment and wildlife.

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.

Benefits

  • Low-maintenance technology
  • Suitable for low heads
  • Favourable acquisition costs
  • Long service life, then 100% recyclable
  • Versatile
  • The ecological value of existing weirs improves if they are converted to incorporate a hydropower screw
  • Can be used as a water lifting screw for drainage and flood protection 


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