The Curtis Turbine is a Compound Impulse Turbine, the compounding limited for only Velocity. The Curtis turbine, invented in 1897, differs significantly from any other type of steam turbine in that it allows for the use of relatively low speeds without introducing any complicated mechanism. The Curtis wheel is widely used as the first stage of steam turbines in various multistage turbines today.
The Curtis Turbine is composed of one Stage of Nozzle as the Single Stage Turbine, followed by two rows of moving blades. These two rows are separated by one row of fixed blades attached to the Turbine Stator which has the function of redirecting the Steam leaving the first row of moving blades to the second row of moving blades. In the Curtis Stage, the total Pressure drop occurs in the nozzles. The pressure in two rows of the blades remains constant. The rotor rotates when steam passes through the nozzle and strikes the turbine blades that are fixed on the rotor. The rotor can be coupled to a drive unit such as a Pump, Blower, Fan, or to an electric generator to generate power.