Stumpf, Johann

SUBJECT AREA: Steam and internal combustion engines

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fl. c. 1900 Germany

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German inventor of a successful design of uniflow steam engine.

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In 1869 Stumpf was commissioned by the Pope Manufacturing Company of Hertford, Connecticut, to set up two triple-expansion, vertical, Corliss pumping engines. He tried to simplify this complicated system and started research with the internal combustion engine and the steam turbine particularly as his models. The construction of steam turbines in several stages where the steam passed through in a unidirectional flow was being pursued at that time, and Stumpf wondered whether it would be possible to raise the efficiency of a reciprocating steam engine to the same thermal level as the turbine by the use of the uniflow principle.

Stumpf began to investigate these principles without studying the work of earlier pioneers like L.J. Todd, which he later thought would have led him astray. It was not until 1908, when he was Professor at the Institute of Technology in Berlin- Charlottenburg, that he patented his successful "una-flow" steam engine. In that year he took out six British patents for improvements in details on his original one Stumpf fully realized the thermal advantages of compressing the residual steam and was able to evolve systems of coping with excessive compression when starting. He also placed steam-jackets around the ends of the cylinder. Stumpf's first engine was built in 1908 by the Erste B runner Maschinenfabrik-Gesellschaft, and licences were taken out by many other manufacturers, including those in Britain and the USA. His engine was developed into the most economical type of reciprocating steam engine.

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Bibliography

1912, The Una-Flow Steam Engine, Munich: R. Oldenbourg (his own account of the una-flow engine).

Further Reading

H.W.Dickinson, 1938, A Short History of the Steam Engine, Cambridge University Press; R.L.Hills, 1989, Power from Steam. A History of the Stationary Steam Engine, Cambridge University Press (both discuss Stumpf's engine).

H.J.Braun, "The National Association of German-American Technologists and technology transfer between Germany and the United States, 1844–1930", History of Technology 8 (provides details of Stumpf's earlier work).

RLH