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 method of assembling a turbine runner while it remains situated in a water passageway. The turbine runner comprises a hub having a longitudinal axis, spaced apart outer and inner surfaces defining a cavity, and a corresponding plurality of blades pivotally connected to the hub. Each blade has a trunnion and is supported in rotation by an associated blade support assembly including at least one trunnion bushing. The cavity substantially encloses the support assemblies. The method comprises the steps of assembling a maintenance platform in the water passageway below the runner, installing for at least one of the blades a new trunnion bushing in the associated blade support assembly, and removing the maintenance platform from the water passageway. The hub has an inner hub for supporting the trunnion bushing, and the inner hub may be split into upper and lower inner hubs which may be uncoupled for installing the new trunnion bushing.

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.