Stream-powered turbine vanes

In a stream-powered turbine adapted to be restrained in a partially submerged condition in a flow of water, said turbine having a shaft, a body rotatably mounted on said shaft and having an outer surface, and at least one axially-elongated vane having an inner end portion secured to said body outer surface, having an outer end portion spaced from said body outer surface, having a leading surface, and having a trailing surface, and wherein said vane has at least one valve opening therethrough, the improvement which comprises:

• valve means mounted on said vane and operable to selectively close said valve opening, said valve means including a flap valve pivotally mounted on said vane for movement toward and away from said trailing surface, said flap valve being adapted to cover said valve opening when said vane enters the stream and adapted to uncover said valve opening when said vane exits said stream;
• and
• shield means mounted on said vane outer end portion and extending away from said vane trailing surface to form a dam-like member over which water must normally pass to contact said vane trailing surface, said shield means having at least one control opening therethrough aligned with said flap valve;
• whereby, when said turnbine rotates to cause said vane to enter the stream, water may pass through said control opening to cause said flap valve to cover said valve opening to insure that said valve opening will be closed when the pressure of said flow is applied to said vane trailing surface.