Porter, Charles Talbot

SUBJECT AREA: Steam and internal combustion engines

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b. 18 January 1826 Auburn, New York, USA

d. 1910 USA

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American inventor of a stone dressing machine, an improved centrifugal governor and a high-speed steam engine.

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Porter graduated from Hamilton College, New York, in 1845, read law in his father's office, and in the autumn of 1847 was admitted to the Bar. He practised for six or seven years in Rochester, New York, and then in New York City. He was drawn into engineering when aged about 30, first through a client who claimed to have invented a revolutionary type of engine and offered Porter the rights to it as payment of a debt. Having lent more money, Porter saw neither the man nor the engine again. Porter followed this with a similar experience over a patent for a stone dressing machine, except this time the machine was built. It proved to be a failure, but Porter set about redesigning it and found that it was vastly improved when it ran faster. His improved machine went into production. It was while trying to get the steam engine that drove the stone dressing machine to run more smoothly that he made a discovery that formed the basis for his subsequent work.

Porter took the ordinary Watt centrifugal governor and increased the speed by a factor of about ten; although he had to reduce the size of the weights, he gained a motion that was powerful. To make the device sufficiently responsive at the right speed, he balanced the centrifugal forces by a counterweight. This prevented the weights flying outwards until the optimum speed was reached, so that the steam valves remained fully open until that point and then the weights reacted more quickly to variations in speed. He took out a patent in 1858, and its importance was quickly recognized. At first he manufactured and sold the governors himself in a specially equipped factory, because this was the only way he felt he could get sufficient accuracy to ensure a perfect action. For marine use, the counterweight was replaced by a spring.

Higher speed had brought the advantage of smoother running and so he thought that the same principles could be applied to the steam engine itself, but it was to take extensive design modifications over several years before his vision was realized. In the winter of 1860–1, J.F. Allen met Porter and sketched out his idea of a new type of steam inlet valve. Porter saw the potential of this for his high-speed engine and Allen took out patents for it in 1862. The valves were driven by a new valve gear designed by Pius Fink. Porter decided to display his engine at the International Exhibition in London in 1862, but it had to be assembled on site because the parts were finished in America only just in time to be shipped to meet the deadline. Running at 150 rpm, the engine caused a sensation, but as it was non-condensing there were few orders. Porter added condensing apparatus and, after the failure of Ormerod Grierson \& Co., entered into an agreement with Joseph Whitworth to build the engines. Four were exhibited at the 1867 Paris Exposition Universelle, but Whitworth and Porter fell out and in 1868 Porter returned to America.

Porter established another factory to build his engine in America, but he ran into all sorts of difficulties, both mechanical and financial. Some engines were built, and serious production was started c. 1874, but again there were further problems and Porter had to leave his firm. High-speed engines based on his designs continued to be made until after 1907 by the Southwark Foundry and Machine Company, Philadelphia, so Porter's ideas were proved viable and led to many other high-speed designs.

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Bibliography

1908, Engineering Reminiscences, New York: J. Wiley \& Sons; reprinted 1985, Bradley, Ill.: Lindsay (autobiography; the main source of information about his life).

Further Reading

R.L.Hills, 1989, Power from Steam. A History of the Stationary Steam Engine, Cambridge University Press (examines his governor and steam engine).

O.Mayr, 1974, "Yankee practice and engineering theory; Charles T.Porter and the dynamics of the high-speed engine", Technology and Culture 16 (4) (examines his governor and steam engine).

RLH