History of the steam engine

"This article primarily deals with the history of the reciprocating-type steam engine.
The parallel development of turbine-type engines is described in the steam turbine article."

The history of the steam engine stretches back as far as the first century AD; the first recorded steam engine being the aeolipile described by Hero of Alexandria. ["turbine." Encyclopedia Britannica. 2007. Encyclopedia Britannica Online. 18 July 2007 ] Over fifteen centuries later, early forms of steam turbines were described by Taqi al-Din in 1551 and Giovanni Branca in 1629. These and other early engines were essentially experimental devices used by inventors to demonstrate the properties of steam.

It was not until 1712 that a truly useful steam engine was developed: the atmospheric engine, invented by Thomas Newcomen. Newcomen's engine was relatively inefficient, but did enable water to be pumped out of mine workings at a depth hitherto impossible. James Watt contributed to the development of the steam engine in many ways, vastly improving the efficiency of Newcomen's design and developing mechanisms to convert the reciprocating motion of a piston into rotary motion suitable for driving factory machinery.

Around 1800, Richard Trevithick introduced engines using high-pressure steam. These were much more powerful than previous engines and could be made small enough for transport applications. Thereafter, technological developments and improvements in manufacturing techniques (partly brought about by the adoption of the steam engine as a power source) resulted in the design of more efficient engines that could be smaller, faster, or more powerful, depending on the intended application.

Steam engines remained the dominant source of power well into the 20th century, when advances in the design of electric motors and internal combustion engines gradually resulted in the vast majority of reciprocating steam engines being replaced in commercial usage.

However, in modern times, steam turbines, an alternative form of steam engine, continue to be used in the generation of electricity. And investigations are being made into the practicalities of using reciprocating engines in 'advanced steam technology' systems.

Precursors

Early uses of steam power

The earliest known rudimentary steam engine and reaction steam turbine, the aeolipile, is described by a mathematician and engineer named Hero of Alexandria (Heron) in 1st century Roman Egypt, as recorded in his manuscript "Spiritalia seu Pneumatica". [Heron Alexandrinus (Hero of Alexandria) (c. 62 CE): "Spiritalia seu Pneumatica". Reprinted 1998 by K G Saur GmbH, Munich. ISBN 3-519-01413-0.] citation
url = http://sdr.lib.umich.edu/cgi/m/mdp/pt?seq=265&view=image&size=100&id=mdp.39015020219674&u=1&num=1
title = Steamboat Days
first1 = Fred Erving
last1 = Dayton
chapter = Two Thousand Years of Steam
publisher = Frederick A. Stokes company
page = 1
year = 1925] Steam ejected tangentially from nozzles caused a pivoted ball to rotate. Its thermal efficiency was low. This suggests that the conversion of steam pressure into mechanical movement was known in Roman Egypt in the 1st century. Hero also devised a machine that used air heated in an altar fire to displace a quantity of water from a closed vessel. The weight of the water was made to pull a hidden rope to operate temple doors. [cite web
last = Hero of Alexandria
first =
authorlink =
coauthors = Bennet Woodcroft (trans.)
title = Temple Doors opened by Fire on an Altar
work = Pneumatics of Hero of Alexandria
publisher = London: Taylor Walton and Maberly (online edition from University of Rochester, Rochester, NY)
date = 1851
url = http://www.history.rochester.edu/steam/hero/section37.html
format =
doi =
accessdate = 2008-04-23] Some historians have conflated the two inventions to assert, incorrectly, that the aeolipile was capable of useful work.

In 1125, Rheims was home to a church that had an organ powered by air escaping from compression "by heated water". A rudimentary impact steam turbine was described in 1551 by Taqi al-Din, a philosopher, astronomer and engineer in 16th century Ottoman Egypt, who exposed a method for rotating a spit by means of a jet of steam playing on rotary vanes around the periphery of a wheel. A similar smoke jack was described by John Wilkins in 1648.Ahmad Y Hassan (1976), "Taqi al-Din and Arabic Mechanical Engineering", pp. 34-5, Institute for the History of Arabic Science, University of Aleppo] Another similar rudimentary steam turbine is shown by Giovanni Branca, an Italian engineer, in 1629 for turning a cylindrical escapement device that alternately lifted and let fall a pair of pestles working in mortars. [http://www.history.rochester.edu/steam/thurston/1878/Chapter1.html University of Rochester, NY, "The growth of the steam engine" online history resource, chapter one] ] The steam flow of these early steam turbines, however, was not concentrated and much of its energy was dissipated in all directions. This would have led to a great waste of energy and so they were never seriously considered for industrial use. They seem to have been usually called "mills".

In 1543, Blasco de Garay is said to have demonstrated the potential of steam power by moving a ship using paddle-wheels with "a vessel of boiling water" included in the apparatus, but its practicality and cost did not impress the authorities who financed the experiment, nor did de Garay leave behind any designs or descriptions of the mechanism he had devised. Sustained attempts to create machines which could provide power with sufficient efficiency to reliably do useful heavy work had to wait until the 17th century. The 1606 patent of another Spanish inventor, Jerónimo de Ayanz y Beaumont, was to eventually influence Thomas Savery. In 1663 Edward Somerset, 2nd Marquess of Worcester published designs for raising water between floors employing a similar principle to that of a coffee percolator. He installed his steam-powered device on the wall of the Great Tower at Raglan Castle. The grooves in the wall where the engine was installed were still to be seen in the 19th century. However, no one was prepared to risk money for such a revolutionary concept, and without backers the machine remained undeveloped. [cite book
last =Thurston
first =Robert Henry
authorlink =
coauthors =
title =A History of the Growth of the Steam-Engine
publisher =Keegan Paul and Trench (reprinted Adamant 2001)
date =1883
location =London
pages = pp21-22
url =
doi =
id =
isbn =1402162057]

Cylinders

One of Denis Papin’s centres of interest was in the creating of a vacuum in a closed cylinder and in Paris in the mid 1670s he collaborated with the Dutch physicist, Huygens’ working on an engine which drove out the air from a cylinder by exploding gunpowder inside it. Realising the incompleteness of the vacuum produced by this means and on moving to England in 1680, Papin devised a version of the same cylinder that obtained a more complete vacuum from boiling water and then allowing the steam to condense; in this way he was able to raise weights by attaching the end of the piston to a rope passing over a pulley. As a demonstration model the system worked, but in order to repeat the process the whole apparatus had to be dismantled and reassembled. Papin quickly saw that to make an automatic cycle the steam would have to be generated separately in a boiler; however as he did not take the project further all we can say is that he invented the reciprocating steam engine conceptually and thus paved the way to Newcomen’s engine. Papin also designed a paddle boat driven by a jet playing on a mill-wheel in a combination of Taqi al Din and Savery's conceptions and he is also credited with a number of significant devices such as the safety valve. Papin's years of research into the problems of harnessing steam was to be play a key part in the development of the first successful industrial engines that soon followed his death.

The first industrial engines

The first attempt to apply a steam engine industrially was the "fire-engine", designed by Thomas Savery in 1698. This was a pistonless steam pump, and apparently not very efficient; nor was it very safe because part of its cycle required steam under pressure supplied by a boiler, while the time, poor plate technology lead to low strength in the pressure vessel, making the boiler prone to explosions. In 1712, Thomas Newcomen and his "atmospheric-engine" demonstrated the first practical industrial engine to satisfy the commercial demand. Newcomen appears to have based his development on Papin's description of early experiments at The Royal Society, to which he most likely had access through acquaintance with a society member, Robert Hooke, who had himself worked with Papin. However Newcomen's design managed to generate a permanent supply of steam separately in a boiler, probably based on Savery's design. Although for safety reasons, the boiler pressure was only a little above atmospheric pressure.

Low-pressure engines

Newcomen "atmospheric" engine

It was Thomas Newcomen with his "atmospheric-engine"of 1712 who can be said to have brought together most of the essential elements established by Papin in order to develop the first practical steam engine for which there could be a commercial demand. This took the shape of a reciprocating beam engine installed at surface level driving a succession of pumps. The engine suspended by chains from one end of a rocking beam, worked on the atmospheric, or vacuum principle. [http://content.cdlib.org/ark:/13030/kt6r29q3kz/?order=1&brand=oac] .Such engines operated by admitting steam at extremely low pressure into the power cylinder. The inlet valve was then closed and the steam cooled, condensing it to a smaller volume of water and thus creating a vacuum in the cylinder. The upper end of the cylinder was open to the atmospheric pressure and lubricated by a layer of water maintained by a trickle feed. The pressure differential between atmosphere and vacuum displaced piston, to the bottom of the cylinder.

The piston was connected by a chain to the end of the great beam pivoted near its middle with the weighted force pumps connected by another chain to the opposite end of the beam which gave the pumping stroke by its own dead weight and provided gravitational force to drive the water up pipes and to return the power piston to the top of the cylinder. The cooling water was sprayed directly inside the cylinder from a cistern that also provided the sealing water to the piston, the still-warm condensate running off into a hot well. The vacuum stroke gave sufficient power to lift and prime the pumps. Although inefficient and extremely heavy on coal, these engines enabled the raising of far greater volumes of water from greater depths than had been hitherto possible.

Watt's separate condenser

Smeaton then made some efficiency improvements to the Newcomen engine, but the big step forward was made by James Watt. In the 1770s the Watt engine was introduced, where steam is condensed by cooling a separate connected compartment, not the cylinder itself. This separate condenser meant that the steam cylinder could be kept hot continuously, and did not use steam simply to heat up the cylinder at the beginning of each stroke (ie the first steam introduced to the cylinder did not simply condense straight away).

James Watt's development of this engine as perfected and marketed from 1774 onwards in partnership and collaboration with Matthew Boulton, led to improved efficiency through use of a separate condensing chamber immersed in a tank of cold water, connected to the working cylinder by a pipe and controlled by a valve. A small vacuum pump connected to the pump side of the beam drew off the warm condensate and delivered it to the hot well, at the same time helping to create the vacuum and draw the condensate out of the cylinder.

The development period was long and difficult, initially carried out by Watt at the University of Glasgow. In 1761 Professor Joseph Black proposed his 'theory of latent heat' which laid the foundations for the development of steam engine technology. Watt applied Black's theory to a model of the Newcomen engine that he had been given to repair. He soon realised that the repeated cooling and reheating of the working cylinder in the Newcomen engine was a source of inefficiency. This led to the development of the separate condenser that allowed the temperature of the cylinder to be maintained at a constant level. Watt's technology enabled the widespread commercial use of stationary steam engines. [ Ogg, David. (1965), "Europe of the Ancien Regime: 1715-1783" Fontana History of Europe, (pp. 117 & 283) ] .

Humphrey Gainsborough produced a model condensing steam engine in the 1760s, which he showed to Richard Lovell Edgeworth, a member of the Lunar Society. Gainsborough believed that Watt had used his ideas for the invention [Tyler, David (2004): "Oxford Dictionary of National Biography". Oxford University Press.] ; however James Watt was not a member of the Lunar Society at this period and his many accounts explaining the succession of thought processes leading to the final design would tend to belie this story.

had been achieved by maintaining a small quantity of water on its upper side. This was no longer possible in Watt's engine due to the presence of the steam, so sealing of the piston and its lubrication was obtained by using a mixture of tallow and oil. The piston rod also passed through a gland on the top cylinder cover sealed in a similar way. [http://www.sciencemuseum.org.uk/on-line/energyhall/page19.asp]

Power was still limited by the low pressure, the displacement of the cylinder, combustion and evaporation rates and condenser capacity. Maximum theoretical efficiency was limited by the relatively low temperature differential on either side of the piston; this meant that for a Watt engine to provide a usable amount of power, the first production engines had to be very large, and were thus expensive to build and install.

Watt double acting and rotary engines

Boulton & Watt, developed the reciprocating engine into the rotative type. Unlike the Newcomen engine, the Watt engine could operate smoothly enough to be connected to a drive shaft—via sun and planet gears—to provide rotary power along with double acting condensing cylinders. The earliest example was build as a demonstrator and was installed in Boulton's factory to work machines for lapping or polishing buttons etc. For this reason it was always known as the "Lap engine" [http://www.sciencemuseum.org.uk/objects/motive_power/1861-46.aspx] [Hulse, David K., The development of rotary motion by steam power by steam power (TEE Publishing Ltd., Leamington, UK., 2001) ISBN 1 85761 119 5] . In early steam engines the piston is usually connected by a rod to a balanced beam, rather than directly to a flywheel, and these engines are therefore known as beam engines. This was in all essentials the steam engine that we know today.

"Strong steam"

As the 18th century advanced, the call was for higher pressures; this was strongly resisted by Watt who with some justification, mistrusted the materials resistance and the boiler technology of the day. The first known advocate of "strong steam" was Leupold in his scheme for an engine that appeared in encyclopaedic works from around 1725. Various projects for steam propelled boats and vehicles also appeared throughout the century one of the most promising being Nicolas-Joseph Cugnot's who demonstrated his "fardier" (steam wagon), in 1769. Whilst the working pressure used for this vehicle is unknown, the small size of the boiler gave insufficient steam production rate to allow the fardier to advance a few hundred metres at a time before having to stop to raise steam. Other projects and models were proposed, but as with William Murdoch's model of 1784 in, many were blocked by Boulton and Watt.

This did not apply in the USA and 1788, a steamboat built by John Fitch operated in regular commercial service along the Delaware river between Philadelphia PA and Burlington NJ, carrying as many as 30 passengers. This boat could typically make 7 to 8 miles per hour, and traveled more than convert|2000|mi|km|-2 during its short length of service. The Fitch steamboat was not a commercial success, as this travel route was adequately covered by relatively good wagon roads. In 1802 William Symington built a practical steamboat, and in 1807 Robert Fulton used the Watt steam engine to power the first commercially successful steamboat.

Oliver Evans in his turn was in favour of "strong steam" which he applied to boat engines and to stationary uses. He was a pioneer of cylindrical boilers; however Evans' boilers did suffer several serious boiler explosions, which tended to lend weight to Watt's qualms.

The importance of raising steam under pressure (from a thermodynamic standpoint) is that it attains a higher temperature. Thus, any engine using high pressure steam operates at a higher temperature and pressure differential than is possible with a low pressure vacuum engine. The high pressure engine thus became the basis for most further development of reciprocating steam technology. Even so, around the year 1800, "high pressure" amounted to what today would be considered very low pressure, i.e. 40-50 psi (276 - 345 kPa), the point being that the high pressure engine in question was non-condensing driven solely by the expansive power of the steam and once that steam had performed work, it was usually exhausted at higher-than-atmospheric pressure. The blast of the exhausting steam into the chimney could be exploited to create induced draught through the fire grate and thus increase the rate of burning, hence creating more heat in a smaller furnace, at the expense of creating back pressure on the exhaust side of the piston. The most important outcome was that engines could be made much smaller than previously for a given power output. There was thus the potential for steam engines to be developed that were small and powerful enough to propel themselves and other objects. As a result, steam power for transportation now became a practicality in the form of ships and land vehicles, which revolutionised cargo businesses, travel, military strategy, and essentially every aspect of society.

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 [Young, Robert: “Timothy Hackworth and the Locomotive”; the Book guild Ltd, Lewes, U.K. (2000) (reprint of 1923 ed.) pp.18-21] .

Trevithick's improvement to the Watt pumping engine

s being updated to conform. Many of these engines were supplied worldwide and gave reliable and efficient service over a great many years with greatly reduced coal consumption. Some of them were very large and the type continued to be built right down to the 1890’s.

Development after Trevithick

"For further details, please see steam engine."

References