Francis turbines are the most commonly used type of hydro turbine in the world. Around 60% of the global hydroelectric capacity is provided through Francis turbines. Used particularly in large-scale hydroelectric plants, they are versatile turbines that can be used in various hydraulic heads and water flow rates.
Francis turbines can operate with heads of up to 600 meters and generate up to 500 MW power.
Firmametal produces open-channel type Francis turbines specific to low heads, as well as Francis scroll-turbines with horizontal and vertical design for medium and high heads. The turbine / generator shaft can be horizontal or vertical depending on customer requirements. The most common use is the spiral turbine with the runner directly connected to the generator and positioned horizontally. This design offers reduced production and maintenance costs.
In Francis turbines, action valves direct water to the turbine wheels after it enters the spiral or scroll section. The water changes direction after passing through the wheels and its pressure drops. It is then discharged into the turbine outlet channel through the draft pipe. Flow rate control is achieved by opening and closing the valves. The motion of these valves is controlled by a speed regulator for independent operation or through a PLC-controlled actuator for operation in parallel with the distribution network.