ANDRITZ Atro hydrodynamic screws

Functioning of hydrodynamic screws and their advantages

With the help of hydrodynamic screws, even small flowing waters serve as a valuable, renewable source of energy. Hydrodynamic screws transform the energy difference between two different levels of flowing water into mechanical energy, which is applied to the rotor shaft to drive a generator. Thus, by inverting the energy flow in its operation, a screw pump is turned into a power generator.

Hydrodynamic screws reach high efficiencies of up to 92%. Varying water heads and varying water flow rates upstream and downstream of the screw only have a marginal effect on the efficiency and do not affect their functioning and operation. With hydrodynamic screws, even small hydrodynamic potentials at powers from 1 kW (up to 500 kW) can be exploited economically.

The screw and trough can be embedded easily into the natural surroundings, and the technology is very fish-friendly. With hydrodynamic screws, the fine-screening installations for protection against floating objects and fish that are needed for small turbine installations can be omitted. Only a coarse screen needs to be installed, and any objects and fish can pass through the screw unhindered and unharmed. Small hydrodynamic facilities bear immense potential for drawing energy from naturally flowing waters. Another positive aspect is that the water becomes enriched with oxygen, which in turn improves the quality of the water downstream.

Main advantages of hydrodynamic screws at a glance

• No control system - the screw adapts automatically to water supply and supply frequency
• The efficiency (up to 92%) is higher than with water wheels or small turbines (up to 500 kW)
• A flat and stable efficiency gradient guarantees highest efficiencies at any operating point
• Robust design, hardly any wear, almost maintenance-free
• No fine-screening, no cleaning
• Only a small amount of underground digging required in comparison to small turbines
• Very fish-friendly

Examples of use

• Replacement for small hydro-power units (up to 500 kW) which need reconditioning
• Replacement for defective water wheels
• Clean water outlet of sewage treatment plants
• Residual water screw for installation in existing channels or weirs

ANDRITZ hydrodynamic screws