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"Steam enters at E and gradually expands in volume until it exhausts at G. The rotor is usually built in three different diameters to facilitate mechanical construction and to avoid excessively small and excessively large vanes. It is thus possible to use a large number of vanes of the same size." —Derr, 1911

Cross Sectional View of Parsons Turbine

"Steam enters at E and gradually expands in volume until it exhausts at G. The rotor is usually built…