VERTICAL AXIS WATER CURRENT TURBINE

The present invention refers to a vertical axis hydraulic turbine to exploit energy from marine tidal currents or river streams, converting it into electric energy. The vertical axis hydraulic turbine is characterized by a rotor equipped with three blades each of which is pivotally connected on the rotor. During the revolution the blades are able to pivot within a range from 80 to 90 deg. with respect to the radial direction of the rotor. This variable pitch system for the blades is obtained through a self-acting system, based on the equilibrium obtained between centrifugal forces and hydrodynamic forces on the blade and the pitch blade range is limited by two stops placed opportunely. Through the blade pitch, the turbine is characterized by high torques that allow spontaneous starting without the need of an ignition device. The prototype of this turbine, named KOBOLD turbine, has been installed under a floating platform in 2002 in Messina strait within the ENERMAR project. The first turbine was characterized by a diameter of 5 m and a blade height of 5 m. The turbine, was rated at about 100 kW power with a current speed of 3,0 m/s. UNIDO (United Nations Industrial Developments Organisation) has chosen the Kobold technology for the electrification of developing countries in a program that foresees the installation of three pilot plants in Southeast Asia. The installation of a 150 kW system has been planned in Indonesia in JUne, 2012.