Thomas Newcomen
1663-1729
English Inventor
Thomas Newcomen is often acclaimed as the inventor of the steam engine. An ironmonger by training, he converted Thomas Savery's primitive steam pump into a true, if inefficient, source of motive power. Originally developed to remove water from coal mines, the steam engine, as further refined by James Watt, provided the first reliable source of mechanical energy other than muscle, wind, or water power, and thus provided the key technical stimulus for revolutions in both transportation and industrial production.
Thomas Newcomen was born into a family of religious dissenters in Dartmouth, Devonshire, England. Nothing is known with certainty about his education or training, but it appears he entered into business in 1685 as an ironmonger (blacksmith and dealer in metals) with a partner, John Calley, a plumber and a fellow member of the Baptist sect. How Newcomen came to be interested in developing a steam engine, and how much contact Newcomen had with Thomas Savery (1650-1715), also a native of the Devonshire region and the inventor of the steam pump, is also a matter of speculation. Such contact is, however, fairly likely, as Newcomen visited the tin mines in the area and had some idea of their operation and problems.
Savery's steam pump had been developed for the rapidly growing coal mining industry, which had come into being to provide fuel in place of wood for heating, the forests of England having been alarmingly depleted. Coal was available in abundance, but mineshafts were likely to fill with water, which needed to be removed. Savery's invention, introduced around 1700, involved filling a pipeline to the water with steam, then cooling the source of the steam until it condensed to form liquid water, creating a vacuum that would pull the water upwards. Then, using additional steam applied from below, the water was pushed to the surface. Savery's pump, which required steam under pressure, was dangerous to operate as leaks and ruptures often occurred.
Newcomen introduced a cylinder and piston, which could be filled with steam pushing the piston one way and then cooled so that the steam condensed to form liquid water, leaving a near vacuum so that air pressure would push the piston back. Steam pressures only slightly greater than one atmosphere were then required, and atmospheric pressure did most of the work. At first, cooling was accomplished by passing water around the cylinder, but in 1704 or 1705, by a happy accident, cool water leaked into the cylinder, producing immediate condensation for a much faster power cycle. The first successful engine, with cool water injection into the cylinder at the appropriate times, was demonstrated in 1712. It was inefficient in that much of the heat energy was wasted heating up the cylinder after each cooling. The Scottish engineer James Watt (1736-1819) would eliminate this problem by adding a separate condenser, which the steam entered after doing its work on the piston, so that the cylinder could remain hot.
It is now generally agreed that Newcomen was a skilled artisan who did not have a sound understanding of scientific principles but who worked by trial and error, combining bits of technology from earlier inventions. Nonetheless, it was the Newcomen engine, as improved by Watt, that led to the era of steamships and railroads and to factories built around powerful machinery. The steam engine would also serve as the basis for a new branch of physical science—thermodynamics—the study of the interconversion of heat and mechanical work, from which the modern laws of energy conservation and entropy increase would emerge in the nineteenth century.
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