Abstract: A turbine wheel and bucket assembly comprising a wheel having a peripheral rim machined to include a dovetail shape about the circumference of the rim, interrupted only by a bucket installation slot; and a plurality of buckets installed on the wheel, each bucket having a dovetail portion and blade portion, with the dovetail portion machined to include a complimentary dovetail shape enabling each bucket to be slidably received on the wheel dovetail shape; each bucket having an integral cover at a radial tip of the blade portion, each cover having axially extending surfaces on either side of angled contact surfaces adapted to engage mating contact surfaces of adjacent covers such that the buckets are pretwisted in a first direction. The dovetail shape includes a keyway and a complimentary key is provided on the rim of the wheel, the key receivable within the keyway to prevent rotation of the dovetail portion of the bucket relative to the wheel.

Abstract: In a steam turbine, a device for keying hubs of adjacent wheels together, wherein the wheels are not an integral part of the shaft of a rotor of the steam turbine and may be secured to the shaft by an interference shrink-fit at the surface of a bore through the hub of the wheel, comprises a substantially I-beam shaped key disposed in a keyway formed between adjacent hubs. A lip extends axially from the outer periphery of a pair of opposing end faces of adjacent hubs, the outboard surface of one lip of the pair of opposing end faces being in close proximity to the outboard lip of the other lip of the pair of opposing end faces. A respective pair of lands on each respective pair of opposing end faces defines a substantially radial slot respectively between the pair of lands. Streamlined fillets respectively transition the leading and trailing faces of each respective member of the pair of lands to the respective opposing end face.

Abstract: In a steam turbine, apparatus for preventing rotation of a first wheel with respect to a second wheel adjacent the first wheel, wherein the first and second wheels are secured to a shaft of a rotor of the steam turbine by an interference shrink fit, comprises a key disposed in a keyway defined by and between respective hubs of the wheels. The key is exposed to ambient environment of the rotor and is spaced from the axial ends of the keyway to permit steam to flow through portions of the keyway. Key and keyway configurations for prohibiting radial movement of the key are illustrated.