Each stage acts as a velocity compounded impulse turbine. It is a three stage pressure compounded impulse turbine. MW impulse turbine was added in 1914(No11). In 1827 the Frenchmen Real and Pichon patented and constructed a compound impulse turbine. The pressure compounded Impulse turbine is also called as Rateau turbine, after its inventor. An impulse turbine has fixed nozzles that orient the steam flow into high speed jets. In 1903 Zoelly developed a multi-stage axial flow impulse turbine in collaboration with Professor Stodola. De Laval's impulse turbine is simpler, less expensive and does not need to be pressure-proof.