Born in 1878, in what is now in the German port of Bremerhaven, Wolfgang Gaede made unique contributions to the theoretical and practical applications of vacuum technology during the era of accelerating industrialization which took place in the latter part of the 19th and first half of the 20th Centuries.

Wolfgang Gaede graduated from the University of Freiburg in physics in 1901, after previously having studied medicine. He developed the first of his vacuum pumps in response to the needs of his assistantship studies when only a Sprengel pump was available. His rotating mercury (high vacuum) pump was patented in 1905, a year after he was approached by Alfred Schmidt of Leybold to produce the pump. Leybold had lost out to Pfeiffer who had a license to manufacture a Geryk pump, but Gaede’s mechanism fitted the gap in Leybold’s vacuum line of business and was the start of a long (and in no small measure lucrative) partnership. Indeed his royalties partly funded his private laboratory where with additional funding from Leybold he developed products exclusively for Leybold to produce and market. Evidence suggests that Gaede never developed a pump at Leybold’s demand and glorified in his free-hand. In 1915 Gaede invented the high vacuum mercury vapor diffusion pump allowing hitherto un-paralleled high vacuum pressure.

Gaede had a range of interests outside vacuum with patents including wireless and refrigerators and received a full professorship in 1919 at the Institute of Technology, Karlsruhe. He was an acknowledged peer of luminary vacuum scientists of the age. He did however have a mistaken belief about the nature of desorption (antagonistic to Knuden’s cosinusoidal law), but despite this, he recognized the potential of molecular drag (friction) to develop the Gaede molecular pump (19). The drag process is the principle of molecular drag pumping mechanisms in contemporary technology. In the 1930’s Gaede further developed large capacity rotary vane pumps and the principle of gas ballast; an elegant application of thermodynamics and kinetic theory. Gas ballast is a controlled flow of gas into the chamber of a rotary before maximum compression is achieved. This allows discharge of vapour without condensation thus allowing vapour pumping without the stalling consequences and damaging effects to the pump resulting from condensation.

In 1934 Gaede became a victim of the Nazi government’s Gestapo ‘witch-hunts’ of universities and was forced to retire prematurely from his post. He later located to laboratories in Munich. Leybold paid his expenses and compensation as Gaede continued to hold the license but without receiving any royalties. Allied bombing destroyed his laboratory buildings in 1944 and Gaede died in 1945. soon after the end of the war in Europe.

Gaede’s contributions to vacuum are still applied applied widely today. His approach showed a wonderful balance of collaboration with industry from which the Leybold Vacuum company benefited immensely. The Gaede Prize of the German Physical Society and the Gaede-Langmuir medal of the American Vacuum Society are honours in his name and recognize his contributions in perpetuity.

The Gaede

Andrew Chew
November 2007
Wolfgang Gaede - Pioneer of Vacuum technology
H. Henning Vakuum in Forschung und Praxis Volume 13, Issue 3 , Pages 180 – 186 (2001)

Vacuum Science and Technology: Pioneers of the 20th Century P. A. Redhead Springer (1994) p43 ISBN 1563962489