Abstract: A turbine, adaptable to improve the survivability of fish present in water flowing therethrough, includes a hub and associated runner blades. Each blade comprises an inner edge and a distal outer edge, a leading edge and a trailing edge separated by a water directing surface. Each blade is rotatable relative to the hub about a blade rotational axis. The turbine is provided with a gap shielding device designed to shield a gap formed between the hub and the blade inner edge as the blade is rotated about its axis. The gap shielding device may comprise a plurality of independently biased pins, a plurality of fluid jets, a plurality of flexible members, a fluid-filled boot, and combinations thereof.

Abstract: A turbine installation having reduced inner and outer gaps comprises a water passageway and a turbine runner disposed in the passageway downstream of a discharge ring. The turbine runner includes a hollow hub having spaced apart inner and outer surfaces and a longitudinal axis and a plurality of runner blades. Each blade comprises a hydrofoil having an inner edge and a distal outer edge, a leading edge and a trailing edge separated by a water directing surface. Each blade is pivotally connected to the hub about a rotational axis extending in a direction generally perpendicular to the longitudinal axis so that its inner edge is proximate the hub. Each blade is rotatable between a maximum pitch position and a minimum pitch position. The discharge ring has a spherical configuration cooperable with the outer edge of each of the blades to reduce an outer gap formed between the outer edge of each of the blades and the passageway.

Abstract: A turbine, adaptable to improve the survivability of fish present in water flowing therethrough, includes a hub and associated runner blades. Each blade comprises an inner edge and a distal outer edge, a leading edge and a trailing edge separated by a water directing surface. Each blade is rotatable relative to the hub about a blade rotational axis. The turbine is provided with features designed to shield a gap formed between the hub and the blade inner edge as the blade is rotated about its axis.