Litostroj - Francis Turbines
Design principle and range of use: Francis turbine is characterized by a fixed-blade Francis runner that is hydraulically optimized for a narrow operating range. Traditionally, Francis turbine has been considered to be a simple and robust machine suitable for exploitation of water energy at a wide range of head, from 30 m up to 750 m.
General description & our setup
The unit is normally isolated by means of a main inlet valve, which is positioned between the penstock and the welded steel spiral case. Francis turbine can be designed in either vertical or horizontal shaft setup.
The main advantage of a horizontal unit with Francis turbine is compact design, competitive price and simple assembly and maintenance.
Depending on the water passage system safety or ramping requirements, a unit with Francis turbine can be equipped with a pressure relief or water-energy dissipation valve.
Our long experience in design and supply of the Francis turbine worldwide includes all the above setup options.
Our latest development of Francis runner hydraulic design has extended the range of use of the Francis turbine, that is, to a wider range of head and discharge. Litostroj Power offers a large variety of hydraulic design and other solutions custom-tailored for specific requirements and operating conditions of the unit and other customer’s needs.
Throughout the decades, Litostroj Power has supplied or upgraded more than 450 Francis turbines of different configurations, with an output of more than 15 GW in total.
Special solutions
Double Francis turbine is our unique horizontal solution with a single spiral case and two distributors, which can be controlled individually. Such solution offered by Litostroj Power allows to extend the operating range down to 15% (or below) of rated discharge and in this aspect represents an ideal solution for a plant with particularly varying discharge through the year.
Most recent achievement is a hydraulic profile which allows wide range operation even bellow 15% of rated discharge.
Types
- Vertical-shaft Francis turbine
- Horizontal-shaft Francis turbine
- Vertical or horizontal-shaft Francis turbine with pressure-relief (or ramping) valve
- Double Francis turbine
- Twin horizontal-shaft Francis turbine
- Camel-back unit with Francis turbine
Main features
- Heads from 30 m up to 750 m
- Wide range of discharges
- Outputs up to 350 MW
- Runner diameters up to 7 m
- Wide range of nominal rotational speeds