Hydro-turbine runner

The present invention relates generally to hydroelectric turbine installations. More particularly, this invention pertains to hydroelectric installations utilizing propeller-type turbines in which the angular position of the runner blades relative to the hub of the turbine or propeller, i.e. the pitch of the blades, is adjustable. A turbine installation comprising a turbine in combination with an electrical closed-loop control system. The turbine is disposed in a flow of water for producing electrical energy. The turbine includes a hollow hub and a plurality of runner blades pivotally connected to a hollow hub. Each blade comprises a hydrofoil being bounded by an inner surface and a distal outer surface, a leading edge and a trailing edge separated by a water directing surface. The blades are adjustable in pitch from a maximum pitch position in which an inner portion of the water directing surface extends substantially in a direction of the water flow, to a minimum pitch position in which an outer portion of the water directing surface is substantially perpendicular to the water flow. The hollow hub has spaced apart inner and outer surfaces and a hub longitudinal axis. Each blade is pivotally connected to the hub about a rotational axis. At least a portion of the outer surface of the hub swept by the inner surfaces of the blades during rotation of the blades from the maximum pitch to the minimum pitch is spherically-shaped. The inner surfaces of the blades substantially conform to the spherical outer surface portion of the hub, thereby reducing inner gaps formed therebetween. At least one of the blades includes a seal attached to the inner surface of the at least one of the blades. The seal is effectively in contact with the spherical outer surface portion of the hub as the blades are rotated about their axis, thereby further reducing the inner gaps. The turbine installation also includes an electrical closed-loop control system including a processor and sensors. The control system adjusts the pitch of the blades in response to electrical signals from the sensors.