born May 9, 1845, Blasenborg, Swed. died Feb. 2, 1913, Stockholm Swedish scientist, engineer, and inventor. Laval built his first impulse steam turbine in 1882. Further advances followed, including a reversible turbine for marine use. A Laval reaction turbine attained a speed of 42,000 revolutions per minute. By 1896 he was operating a complete power plant using an initial steam pressure of 3,400 lbs per sq in. He invented and developed the divergent nozzle to deliver steam to the turbine blades. His flexible shaft and double-helical gear formed the foundation for most subsequent steam turbine development