ZOELLY

SWITZERLAND (see also List of Individuals)

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11.4.1862 Sambaya/ME - 30.3.1937 Zürich/CH

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Heinrich Zoelly graduated as a mechanical engineer from ETH Zurich in 1882. In 1886, he became a collaborator of Escher & Wyss Company in Zurich.

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Whereas Escher & Wyss was around 1900 a known furnisher of hydraulic turbines, thermal turbines had rarely been designed despite their similarity. Zoelly initiated research with wheels propelled by a steam jet similar to the Pelton type turbine. He learned that a purely axial turbine consisting of a series of guide vanes and wheels had an improved performance using a gas discharge. Zoelly discussed the design with his former teacher Aurel Stodola (1859-1942), later a pioneer of gas turbines. Stodola added to the turbine in terms of stability and vibrations. Whereas gas turbines were developed by Charles A. Parsons (1854-1931) in England, Auguste Rateau (1863-1930) in France and Gustav de Laval (1845-1913) in Sweden, Zoelly appears to have been particularly aim-oriented and supported by a large company with a first design in 1903. Its thermodynamic efficiency was excellent for the small pressure and temperature applied. Escher & Wyss built the last piston-steam make ten years later and specialized on Zoelly's multi-stage steam turbine. The negotiations with patent offices were hard, because Rateau claimed priority over Zoelly's design. His gas turbine was considered an alternative from 1911. Zoelly as chief engineer of Escher & Wyss developed also the hydraulic turbine for low head application. An in-house hydraulic laboratory was erected after World War II. Zoelly was previously supported by the ETH professors Franz Prasil (1857-1929), Robert Dubs (1880-1963) and Jakob Ackeret (1898-1981). The gas turbines, in turn, were successfully implemented in locomotives and vessels, with Escher & Wyss as one of the prime furnishers of the world market. Zoelly was awarded in 1912 the Honorary Doctorate from ETH.

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_{Anonymous (1937). Heinrich Zoelly-Veillon. Schweizerische Bauzeitung 110(17): 212-213. P}

_{Dünki, R. (2006). Heinrich Moritz Zoelly. Stadtarchiv: Zürich.}

_{Keller, C. (1962). Dr. Heinrich Zoelly, der Ingenieur. Neumüller 22(3): 19-23. P}

_{Schmid, H.-R. (1968). Drei Zürcher Pioniere: Paul Usteri, Heinrich Zoelly, Karl Bretscher. Schweizer Pioniere der Wirtschaft und Technik 19: Meilen.}

_{Strumphler, J. (1909). Stoomturbines met speziale vermelding der Zoelly-stoomturbine. De Ingenieur 24(7): 139-148.}

_{Zoelly, H. (1901). Neuere Turbinenanlagen. Zeitschrift Verein Deutscher Ingenieure 45(34): 1189-1197; 45(35): 1239-1246.}

_{Zoelly, H. (1930). The Zoelly turbo-locomotive. Trans. World Power Conference Tokyo: 1-30.}