Editing Steam engine (section)

{{short description|Engine that uses steam to perform mechanical work}}
{{about||the railway engine|Steam locomotive|the steam turbine|Steam turbine}}
{{redirect2|Steam machine|Steam-powered|the video game distribution service|Steam (service)|other uses|Steam machine (disambiguation)}}
{{Use dmy dates|date=March 2020}}
{{History of technology sidebar}}

[[File:JamesWattEngine.jpg|thumb|upright=1.45|A model of a beam engine featuring James Watt's parallel linkage for double action{{efn|This model was built by Samuel Pemberton between 1880 and 1890.}}]]
<!-- [[File:Grazebrook Beam Engine.jpg|thumb|An 1817 [[Boulton & Watt]] beam [[blowing engine]], used in [[Netherton, West Midlands|Netherton]] at the ironworks of M W Grazebrook. Re-erected on the A38(M) in Birmingham, UK]]
 -->[[File:Stott Park Bobbin Mill Steam Engine.jpg|thumb|A [[Stationary steam engine|mill engine]] from [[Stott Park Bobbin Mill]], Cumbria, England]]
[[File:52 8134 Hoentrop 2012-09-16.jpg|thumb| A [[steam locomotive]] from [[East Germany]]. This [[DR Class 52.80|class]] of engine was built in 1942–1950 and operated until 1988.]]

[[File:Kemna road roller.jpg|thumb|A steam ploughing engine by [[Kemna Bau|Kemna]]|alt=]]
A '''steam engine''' is a [[heat engine]] that performs [[Work (physics)|mechanical work]] using [[steam]] as its [[working fluid]]. The steam engine uses the force produced by steam pressure to push a [[piston]] back and forth inside a [[Cylinder (locomotive)|cylinder]]. This pushing force can be transformed by a [[connecting rod]] and [[Crank (mechanism)|crank]] into [[rotation]]al force for work. The term "steam engine" is most commonly applied to [[reciprocating engine]]s as just described, although some authorities have also referred to the [[steam turbine]] and devices such as Hero's [[aeolipile]] as "steam engines". The essential feature of steam engines is that they are [[external combustion engine]]s,<ref name=miffin>{{cite book|title=American Heritage Dictionary of the English Language |url=https://archive.org/details/americanheritage0000unse_a1o7|url-access=registration|edition=4th |year=2000|publisher=Houghton Mifflin Company}}</ref> where the working fluid is separated from the combustion products. The ideal [[thermodynamic]] cycle used to analyze this process is called the [[Rankine cycle]]. In general usage, the term ''steam engine'' can refer to either complete steam plants (including [[Boiler (power generation)|boilers]] etc.), such as railway [[steam locomotive]]s and [[portable engine]]s, or may refer to the [[piston]] or turbine machinery alone, as in the [[beam engine]] and [[stationary steam engine]].

As noted, steam-driven devices such as the aeolipile were known in the first century AD, and there were a few other uses recorded in the 16th century. In 1606 [[Jerónimo de Ayanz y Beaumont]] patented his invention of the first steam-powered water pump for draining mines.<ref>{{Cite web|url=https://www.livescience.com/44186-who-invented-the-steam-engine.html|title = Who Invented the Steam Engine?|website = [[Live Science]]|date = 19 March 2014}}</ref> [[Thomas Savery]] is considered the inventor of the first commercially used steam powered device, a steam pump that used steam pressure operating directly on the water. The first commercially successful engine that could transmit continuous power to a machine was developed in 1712 by [[Thomas Newcomen]]. [[James Watt]] made a critical improvement in 1764, by removing spent steam to a separate vessel for condensation, greatly improving the amount of work obtained per unit of fuel consumed. By the 19th century, stationary steam engines powered the factories of the [[Industrial Revolution]]. Steam engines replaced [[Sailing ship|sails for ships]] on [[paddle steamer]]s, and steam locomotives operated on the railways.

Reciprocating piston type steam engines were the dominant source of power until the early 20th century. The efficiency of stationary steam engine increased dramatically until about 1922.<ref>{{Cite journal |last=Mierisch |first=Robert Charles |date=May 2018 |title=The History and Future of High Efficiency Steam Engines |url=https://www.engineersaustralia.org.au/sites/default/files/resource-files/2018-06/EHA_Magazine_Vol2_No8_May_2018_0.pdf |journal=EHA Magazine |volume=2 |issue=8 |pages=24–25 |via=engineersaustralia.org.au}}</ref> The highest Rankine Cycle Efficiency of 91% and combined thermal efficiency of 31% was demonstrated and published in 1921 and 1928.<ref>{{Cite book |last=Gebhardt |first=G.F. |title=Steam Power Plant Engineering |publisher=John Wiley and Sons, Inc. |year=1928 |edition=6th |location=USA |pages=405 |language=English}}</ref>   Advances in the design of [[electric motor]]s and [[internal combustion engine]]s resulted in the gradual replacement of steam engines in commercial usage. Steam turbines replaced reciprocating engines in power generation, due to lower cost, higher operating speed, and higher efficiency.<ref Name="Wiser" /> Note that small scale steam turbines are much less efficient than large ones.<ref>{{Cite book |last=Green |first=Don |title=Perry's Chemical Engineers' Handbook |publisher=McGraw-Hill |year=1997 |isbn=0-07-049841-5 |edition=7th |location=USA |pages=29–24 |language=English}}</ref>

{{as of|2023}}, large reciprocating piston steam engines are still being manufactured in Germany.<ref>{{Cite web |date=2023-10-05 |title=Spilling Products |url=https://www.spilling.de |access-date=2023-10-05 |website=www.spilling.de}}</ref>