Since its introduction in the mid-1950s, General Electric’s 26-in last stage bucket for large steam turbines has proven to be a popular and durable design. Since that time, however, major advances have been made in aerodynamic and structural design methods and manufacturing technology.
This paper describes an improved 26-in. last-stage bucket which has been developed for application to new large steam turbines and as replacement rows in operating units. The new bucket is a design having continuous coupling at the outermost periphery and near the midpoint of the vane, and benefits the user through substantial efficiency gains and improved reliability margins.