Skip to main content
Select Source:

Steam Engine

Steam engine

A steam engine is a machine that converts the heat energy of steam into mechanical energy. A steam engine passes its steam into a cylinder, where it then pushes a piston back and forth. It is with this piston movement that the engine can do mechanical work. The steam engine was the major power source of the Industrial Revolution in Europe in the eighteenth and nineteenth centuries. It dominated industry and transportation for 150 years.

History

The first steam-powered machine was built in 1698 by the English military engineer Thomas Savery (c. 16501715). His invention, designed to pump water out of coal mines, was known as the Miner's Friend. The machine, which had no moving parts, consisted of a simple boilera steam chamber whose valves were located on the surfaceand a pipe leading to the water in the mine below. Water was heated in the boiler chamber until its steam filled the chamber, forcing out any remaining water or air. The valves were then closed and cold water was sprayed over the chamber. This chilled and condensed the steam inside to form a vacuum. When the valves were reopened, the vacuum sucked up the water from the mine, and the process could then be repeated.

A few years later, an English engineer and partner of Savery named Thomas Newcomen (16631729) improved the steam pump. He increased efficiency by setting a moving piston inside a cylinder, a technique still in use today. A cylindera long, thin, closed chamber separate from the boilerreplaced the large, open boiler chamber. A pistona sliding piece that fits in the cylinderwas used to create motion instead of a vacuum. Steam filled the cylinder from an open valve. When filled, the cylinder was sprayed with water, causing the steam inside to condense into water and create a partial vacuum. The pressure of the outside air then forced the piston down, producing a power stroke. The piston was connected to a beam, which was connected to a water pump at the bottom of the mine by a pump-rod. Through these connections, the movement of the piston caused the water pump to suck up the water.

Words to Know

Condenser: An instrument for cooling air or gases.

Cylinder: The chamber of an engine in which the piston moves.

Piston: A sliding piece that is moved by or moves against fluid pressure within a cylindrical vessel or chamber.

Turbine: An engine that moves in a circular motion when force, such as moving water, is applied to its series of baffles (thin plates or screens) radiating from a central shaft.

Watt's breakthrough

The most important improvement in steam engine design was brought about by the Scottish engineer James Watt (17361819). He set out to improve the performance of Newcomen's engine and by 1769 had arrived at the conclusion: if the steam were condensed separately from the cylinder, the cylinder could always be kept hot. That year he introduced the design of a steam engine that had a separate condenser and sealed cylinders. Since this kept the heating and cooling processes separate, his machine could work constantly, without any long pause at each cycle to reheat the cylinder. Watt's refined steam engine design used one-third less fuel than a comparable Newcomen engine.

Over the next fifteen years, Watt continued to improve his engine and made three significant additions. He introduced the centrifugal governor, a device that could control steam output and engine speed. He made the engine double-acting by allowing steam to enter alternately on either side of the piston. This allowed the engine to work rapidly and deliver power on the downward as well as on the upward piston stroke. Most important, he attached a flywheel to the engine.

Flywheels allow the engine to run more smoothly by creating a more constant load, and they convert the conventional back-and-forth power stroke into a circular (rotary) motion that can be adapted more readily to power machinery. By 1790, Watt's improved steam engine offered a powerful, reliable power source that could be located almost anywhere. It was used to pump bellows for blast furnaces, to power huge hammers

for shaping and strengthening forged metals, and to turn machinery at textile mills. More than anything, it was Watt's steam engine that speeded up the Industrial Revolution both in England and the rest of the world.

High-pressure engines

The next advance in steam engine technology involved the realization that steam itself, rather than the condensing of steam to create a vacuum, could power an engine. In 1804, American inventor Oliver Evans (17551819) designed the first high-pressure, non-condensing engine. The engine, which was stationary, operated at 30 revolutions per minute and was used to power a marble-cutting saw. The high-pressure engines used large cylindrical tanks of water heated from beneath to produce steam.

Steam was successfully adapted to power boats in 1802 and railways in 1829. Later, some of the first automobiles were powered by steam. In the 1880s, the English engineer Charles A. Parsons (18541931) produced the first steam turbine. By 1900, the steam engine had evolved into a highly sophisticated and powerful engine that propelled huge ships on the oceans and ran turbogenerators that supplied electricity.

Once the dominant power source, steam engines eventually declined in popularity as other power sources became available. Although there were more than 60,000 steam cars made in the United States between 1897 and 1927, the steam engine eventually gave way to the internal-combustion engine as a power source for vehicles.

[See also Diesel engine; Internal-combustion engine; Jet engine ]

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Steam Engine." UXL Encyclopedia of Science. . Encyclopedia.com. 24 Jul. 2017 <http://www.encyclopedia.com>.

"Steam Engine." UXL Encyclopedia of Science. . Encyclopedia.com. (July 24, 2017). http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/steam-engine

"Steam Engine." UXL Encyclopedia of Science. . Retrieved July 24, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/steam-engine

steam-engines

steam-engines are machines employing steam pressure and condensation to generate motion. Thomas Savery's device (1698) pumped water by partial vacuum, without moving parts, and while engines on his principles were still in use in the 1790s, Newcomen's atmospheric cylinder/piston engine erected near Dudley in 1712 established the fundamental principles of steam power. James Watt's separate condenser of 1769 (and reciprocation from 1782) became a source of much-improved technical efficiency once Wilkinson's improved cylinder boring became available (1774), and expressed itself in economy of coal use: by the 1790s Watt engines consumed 70 per cent of the fuel of a comparable Smeaton atmospheric device. Higher capital costs meant that coal prices determined the adoption of Watt technology, and industry located onto the cheapest available coal, still providing half its steam-power in 1800 with atmospheric engines.

Mine drainage was its primary application, where coals were cheap and many engines ran on unsaleable slack, with brewing and milling, water supply, and textiles following, the last before the 1820s often employing stationary steam-power through water-wheels for the even torque needed by early machinery. Wider applications from the 1790s owed more to Trevithick's high-pressure non-condensing and direct acting engines, which powered the first successful marine applications with Symington's Charlotte Dundas (1802—though experimentally proven by Jouffroy at Lyons in 1781), and his validation of the steam carriage (1801) and locomotive (1804). Steam was proven at sea by the voyage of Dodd's Thames from Glasgow to London (1815) and entered general coastal service during the 1820s; and on railways by the Rainhill trials of 1829.

Steam-power in cotton more than doubled 1835–56, and was followed by woollens and linen; the Cornish boiler diffused to produce high pressures at reduced fuel costs; and Stephenson long-boiler and Kitson outside-frame locomotives established the basic pattern of railway motive power. From the Grand Junction's establishment of Crewe (1837), British railways manufactured their own locomotives, with occasional purchases from specialists such as Beyer Peacock, who were otherwise confined to export markets, producing long-term losses in standardization and technical progress. The economical compound steam-engine was little used on British railways, where coal was cheap, whereas it became a standard unit for factory power, and in its ultimate triple-expansion form (after 1880) the key to British shipping and shipbuilding dominance. From the early 1900s, Parsons's marine steam turbine provided still greater speed and economy. Plentiful coal supplies, and the extensive coal/steam engineering industrial base, hereafter represented elements of inertia slowing Britain's adoption of electricity and internal combustion.

J. A. Chartres

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"steam-engines." The Oxford Companion to British History. . Encyclopedia.com. 24 Jul. 2017 <http://www.encyclopedia.com>.

"steam-engines." The Oxford Companion to British History. . Encyclopedia.com. (July 24, 2017). http://www.encyclopedia.com/history/encyclopedias-almanacs-transcripts-and-maps/steam-engines

"steam-engines." The Oxford Companion to British History. . Retrieved July 24, 2017 from Encyclopedia.com: http://www.encyclopedia.com/history/encyclopedias-almanacs-transcripts-and-maps/steam-engines

steam engine

steam engine, machine for converting heat energy into mechanical energy using steam as a medium, or working fluid. When water is converted into steam it expands, its volume increasing about 1,600 times. The force produced by the conversion is the basis of all steam engines. Steam engines operate by having superheated steam force a piston to reciprocate, or move back and forth, in a cylinder. The piston is attached by a connecting rod to a crankshaft that converts the back-and-forth motion of the piston to rotary motion for driving machinery. A flywheel attached to the crankshaft makes the rotary motion smooth and steady. The typical steam engine has an inlet valve at each end of the cylinder. Steam is admitted through one inlet valve, forcing the piston to move to the other end of the cylinder. This steam then exits through an exhaust valve. Steam from the other inlet valve then pushes the piston back to its original position, and the cycle starts again. In a single-cylinder steam engine the exhaust steam is usually expelled directly into the atmosphere. A compounded steam engine has several cylinders, which the steam passes through successively until, leaving the last cylinder, it is condensed into water and returned to the boiler. From the Greek inventor Heron of Alexandria to the Englishmen Thomas Newcomen and John Cawley, many persons contributed to the work of harnessing steam. However, James Watt's steam engine, patented in 1769, provided the first practical solution. Earlier engines depended on atmospheric pressure to push the piston into the cylinder, where a vacuum was created by sudden cooling of its steam content. Watt's use of a separate condenser resulted in a 75% saving in fuel. It also made possible the use of steam pressure to move the piston in both directions. Watt's continuing efforts produced a governor, a mercury steam gauge, and a crank-flywheel mechanism, all of which prepared the steam engine for a major role in the Industrial Revolution. Sailing vessels gave way to steamboats, and stagecoaches yielded to railroad trains as the steam engine was perfected. Transmitted by belts, ropes, shafts, pulleys, and gears, the energy from steam engines drove machines in factories and mills. Now, however, steam engines have been replaced in most applications by more economical and efficient devices, e.g., the steam turbine, the electric motor, and the internal-combustion engine, including the diesel engine. They are still sufficiently economical to be used in industries where steam is necessary for some purpose in addition to that of driving an engine.

See C. W. Pursell, Early Stationary Steam Engines in America (1969); E. Robinson, James Watt and the Steam Revolution (1969); see also bibliography under locomotive.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"steam engine." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 24 Jul. 2017 <http://www.encyclopedia.com>.

"steam engine." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (July 24, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/steam-engine

"steam engine." The Columbia Encyclopedia, 6th ed.. . Retrieved July 24, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/steam-engine

steam engine

steam engine Engine powered by steam. Steam, generated by heating water, is used to produce movement. In some engines, the steam forces pistons to move along cylinders. This results in a reciprocating (back-and-forth) motion. A mechanism usually changes this into rotary motion. Steam locomotives use reciprocating engines. Steam turbines are engines that produce rotary motion directly by using the steam to turn sets of fan-like wheels. In any steam engine, some of the heat used to turn water into steam in a boiler converts into energy of motion. The heat may be produced by burning fuel in a furnace, or may come from a nuclear reactor. The first steam engine, invented by Thomas Savery in 1689, was a form of pump, used to remove water from mines. In 1712, Thomas Newcomen invented a steam-operated pump with pistons. From the 1760s, James Watt improved on Newcomen's ideas and produced more efficient steam engines. This led to the use of steam engines to power machinery in factories. In 1884, English engineer Charles Parsons invented the first practical steam turbine. His machines were so efficient that turbines soon started to replace reciprocating steam engines in power stations.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"steam engine." World Encyclopedia. . Encyclopedia.com. 24 Jul. 2017 <http://www.encyclopedia.com>.

"steam engine." World Encyclopedia. . Encyclopedia.com. (July 24, 2017). http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/steam-engine

"steam engine." World Encyclopedia. . Retrieved July 24, 2017 from Encyclopedia.com: http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/steam-engine

steam engine

steam en·gine • n. an engine that uses the expansion or rapid condensation of steam to generate power. ∎  a steam locomotive.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"steam engine." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. 24 Jul. 2017 <http://www.encyclopedia.com>.

"steam engine." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. (July 24, 2017). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/steam-engine

"steam engine." The Oxford Pocket Dictionary of Current English. . Retrieved July 24, 2017 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/steam-engine