Denis Papin's design for a piston-and-cylinder engine, 1690.In about 1680 the French physicist Denis Papin, with the help of Gottfried Leibniz, built a steam digester for softening bones, i.e. he invented the world's first pressure cooker. Later designs implemented a steam-release valve to keep the device from exploding. By watching the valve rhythmically move up and down Papin conceived of the idea of a piston and cylinder engine. Papin wrote up the designs for such a device (as pictured adjacent), however he never built an actual steam engine. The English engineer Thomas Savery later used Papin's designs to build the world's first operational steam engine.
Papin also designed a paddle boat and is also credited with a number of significant devices such as the safety valve. Sir Samuel Morland also developed ideas for a steam engine during the same period and built a number of steam-engine pumps for King Louis XIV of France in the 1680s.
Early industrial steam engines were designed by Thomas Savery (the "fire-engine", 1698) but it was Thomas Newcomen and his "atmospheric-engine" of 1712 that demonstrated the first operational and practical industrial engine. Together, Newcomen and Savery developed a beam engine that worked on the atmospheric, or vacuum, principle. The first industrial applications of the vacuum engines were in the pumping of water from deep mineshafts. In mineshaft pumps the reciprocating beam was connected to an operating rod that descended the shaft to a pump chamber. The oscillations of the operating rod are transferred to a pump piston that moves the water, through check valves, to the top of the shaft. Early Newcomen engines operated so slowly that the valves were manually opened and closed by an attendant. An improvement was the replacement of manual operation of the valves with an operation derived from the motion of the engine itself, by lengths of rope known as potter cord (Legend has it that this was first done in 1713 by a boy, Humphrey Potter, charged with opening the valves; when he grew bored and wanted to play with the other children he set up ropes to automate the process.)
Humphrey Gainsborough produced a model condensing steam engine in the 1760s, which he showed to Richard Lovell Edgeworth, a member of the Lunar Society. In 1769 James Watt, another member of the Lunar Society, patented the first significant improvements to the Newcomen type vacuum engine that made it much more fuel efficient. Watt's leap was to separate the condensing phase of the vacuum engine into a separate chamber, while keeping the piston and cylinder at the temperature of the steam. Gainsborough believed that Watt had used his ideas for the invention, but there is no proof of this.
Watt, together with his business partner Matthew Boulton, developed these patents into the Watt steam engine in Birmingham, England. The increased efficiency of the Watt engine finally led to the general acceptance and use of steam power in industry. Additionally, unlike the Newcomen engine, the Watt engine operated smoothly enough to be connected to a drive shaft—via sun and planet gears—to provide rotary power. In early steam engines the piston is usually connected to a balanced beam, rather than directly to a connecting rod, and these engines are therefore known as beam engines.
Richard Trevithick's No. 14 Engine, built by Hazeldine and Co., Bridgnorth, about 1804. This was a single-acting, stationary high pressure engine that operated at a working pressure of 50 psi (350 kPa).The next improvement in efficiency came with the American Oliver Evans and the Briton Richard Trevithick's use of high pressure steam. Trevithick built successful industrial high pressure single-acting engines known as Cornish engines. However with increased pressure came much danger as engines and boilers were now likely to fail mechanically by a violent outwards explosion, and there were many early disasters. The most important refinement to the high pressure engine at this point was the safety valve, which releases excess pressure. Reliable and safe operation came only with a great deal of experience and codification of construction, operating, and maintenance procedures.
Nicolas-Joseph Cugnot demonstrated the first functional self-propelled steam vehicle, his "fardier" (steam wagon), in 1769. Arguably, this was the first automobile. While not generally successful as a transportation device, the self-propelled steam tractor proved very useful as a self mobile power source to drive other farm machinery such as grain threshers or hay balers. In 1802 William Symington built the "first practical steamboat", and in 1807 Robert Fulton used the Watt steam engine to power the first commercially successful steamboat. On February 21, 1804 at the Penydarren ironworks at Merthyr Tydfil in South Wales, the first self-propelled railway steam engine or steam locomotive, built by Richard Trevithick, was demonstrated.
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