Bourdon, Eugène

(b. Paris, France, 8 April 1808; d. Paris, 29 September 1884)

instrumentation.

Bourdon was the son of a merchant who, expecting him to enter business, sent him to Nuremberg for two years in order to learn German. After his father’s death in 1830, however, Bourdon spent two years in an optician’s shop and, in 1832, set up his own instrument and machine shop. He moved in 1835 to 71 Faubourg du Temple, and continued to work there until 1872, when his sons took over its management. After his retirement, Bourdon continued to perform experiments that interested him. He died from a fall that occurred while he was testing an anemometer he had designed, one that employed a venturi tube.

In 1832 Bourdon made and presented to the Société d’Encouragement pour l’Industrie Nationale a model of a steam engine with glass cylinders; subsequently he built perhaps two hundred small steam engines. His major contributions were in instrumentation, however, and the most important single innovation was his “metallic manometer,” which in his patent of 18 June 1849 was described as a “pressure gauge without mercury.” This gauge is by far the most widely used for indicating pressures in the range of 15 to 100, 000 pounds per square inch. The sensing element, or transducer, of the gauge was and is the Bourdon tube, which is a metal tube with an elliptical cross section. This tube, bent into a C, a helix, or a spiral, or simply twisted about its central axis (all except the spiral were used by Bourdon in 1851), tends to straighten out when pressure is applied to a fluid within it. When one end will indicate variation of pressure. Obituary notices repeat the story that Bourdon was led to the principle of the Bourdon tube by observing the action of a lead cooling coil under internal pressure. Judging from his painstaking attention to detail, this explanation is not unreasonable. Important aspects of the design of Bourdon tubes are still based upon empirical evidence rather than mathematical analysis.

In 1851, as a result of the success of his gauges at the London International Exhibition, Bourdon was awarded the Legion of Honor.

BIBLIOGRAPHY

A paper by Bourdon on his most famous instrument is “Description de manométres métalliques sans mercure, pour indiquer la pression de la vapeur dans les chaudiéres,” in Bulletin de la Siciété d’encouragement pour l’industrie nationale, 50 (1851), 197–200.

A definitive review of theoretical treatment (17 references) is Robert W. Bradspies, “Bourdon Tubes,” in Glannini Technical Notes (Jan.-Feb., 1961), pp. 1–10, published by the Giannini controls Corp., Duarte, Calif.

Obituary notices are “Eugéne Bourdon,” in Revue scientifique. 3rd ser., 21 (1884), 542–543; and “Notice sur M. Eugéne Bourdon, par M. Henri Tresca,” in Bulletin de la société d’encouragement pour l’industrie nationale, 83 (1884), 515–519.

Eugene S. Ferguson