Model (scale 1:6) 1/4 sectioned of Curtis Steam turbine

Model (scale 1:6), 1/4 sectioned, of Curtis Steam turbine, 500 K.W. output, and 2 segments of casing, each with 2 rows of nozzles. (Wheels, blading and nozzles made in Science Museum)

This type of steam turbine was patented by Mr. C. G. Curtis in 1896 and subsequently developed. The model represents a turbine for driving a dynamo of 500 k.w. output, made by the General Electric Co., U.S.A., in 1904. The turbine is of the impulse type, in which the steam is wholly expanded in diverging nozzles and then has its kinetic energy absorbed by the blades of revolving wheels. In order, however, to reduce the peripheral speed of the wheels to a practical value, two methods are simultaneously employed; firstly, the steam is expanded in two stages by two sets of nozzles, and secondly, each wheel has three sets of blades with intermediate fixed guide blades which redirect the steam, after passing through one set, on to the succeeding sets. This combined method gives a large reduction in the peripheral speed with a small number of wheels and blades.