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The Newcomen Memorial Engine can be seen in Dartmouth, home of Thomas Newcomen at The Engine House, Mayors Avenue, Dartmouth, Devon, TQ6 9YY. See the 'Discover Dartmouth' Newcomen Engine webpage for more details.
See Wikipedia entry for an animation showing the operating cycle of the Newcomen engine.
General
The atmospheric engine invented by Thomas Newcomen, today referred to as a Newcomen steam engine (or simply Newcomen engine), was the first practical device to harness the power of steam to produce mechanical work. Newcomen engines were used throughout Britain and Europe principally to pump water out of mines, starting in the early 18th century. James Watt later developed improved steam engines. Although Watt is far more famous today, Newcomen rightly deserves the first credit for the widespread introduction of steam power.
Prior to Newcomen starting his development work, a number of small steam engines of various sorts had been built, but most were essentially novelties. Around 1600 a number of experimenters used steam to power fountains, first filling a container with water, then pressurizing it with steam to force it out.
In 1662 Edward Somerset, 2nd Marquis of Worcester, published a book containing several ideas he had been working on. One was a steam-powered fountain, which used a vacuum instead of positive pressure. In his proposal two containers would alternately be filled with steam and then allowed to condense to produce a vacuum that would draw up more water from a well. A new charge of steam then pushed the water out as in earlier designs. By running the two containers back to back the fountain could be made somewhat continuous.
In 1698 Thomas Savery patented his 'fire engine', a steam powered pump he called the Miner's Friend, applied to pumping out mines. Steam was admitted to a sealed container and then condensed. The vacuum thus created was used to draw water from the sump at the bottom of the mine. The process of cooling and creating the vacuum was fairly slow, so Savery later added a small water inlet or spray to quickly cool the steam. The lift to the vessel was limited to about thirty feet. Steam pressure could then be used to lift water above the vessel, but the problems of dealing with steam at any useful pressure may have been insurmountable. Swedish engineer Marten Triewald, writing in 1734 after residing in England between 1716 and 1726, stated that Newcomen had no knowledge whatever of the speculations of Captain Savery. Further, Stephen Switzer, writing in 1729, stated that Newcomen was as early in his Invention as Mr. Savery.
Because of the limited lift, deeper mines needed some sort of mechanical pump, one that lifted the water directly instead of "sucking" it up. Such pumps were common already, but required a vertical reciprocating action that Savery's system did not provide.
Savery called his invention an 'engine', but it could not transmit its power to any external device. There were evidently high hopes for the Miner's Friend, which led Parliament to extend the life of the patent by 21 years, so that the 1699 patent would not expire until 1733. Unfortunately, Savery's device proved much less successful than had been hoped.
Several other experimenters attempted to provide mechanical work from existing engine designs. One of the most interesting was that of Denis Papin, who succeeded in raising a piston by boiling water in a cylinder, and showed that the vacuum created when the steam condensed could lift a heavy weight. However, he failed to develop it for practical application.
We do not know whether Thomas Newcomen and his business partner John Calley were familiar with the principles demonstrated by Savery and Papin, but those principles were applied in their development of the Beam Engine, in which a large wooden beam rocked up and down upon a central fulcrum. Instead of siphoning the water up, as in Savery's engine, a cylinder pump at the bottom of the mine was operated by the motion of the beam. The engine's cylinder was filled with steam from a boiler (usually directly below it). This was condensed using a jet of water, creating a vacuum below the piston. Atmospheric pressure acted on the top of the piston, pushing it down. It was attached by a chain to one end of a large wooden beam, thus raising the pump's piston attached to the other end by a chain and rods.
The concept seems simple and obvious through modern eyes, but a considerable amount of hard work, ingenuity, luck, ironworking knowledge and skilled craftsmanship were needed to make the Newcomen engine a commercial reality.
It is probable that the first Newcomen engine was in Cornwall, but its location is uncertain. This was followed by two in the Black Country, of which the more famous was that erected at the Conygree Coalworks near Dudley, but this was probably preceded by one built a mile and a half east of Wolverhampton. Both these were used by Newcomen and his partner John Calley to pump out water-filled coal mines. A working replica can today be seen at the nearby Black Country Living Museum, which stands on another part of what was Lord Dudley's Conygree Park. Soon orders from wet mines all over England were coming in, and some have suggested that word of his achievement was spread through his Baptist connections. The Newcomen engine was hardly used in North America due to disputes regarding its possible interference with the production of traditionally made beaver pelts.
Since Savery's patent had not yet run out, Newcomen operated under that patent, since its term was much longer than any Newcomen could have easily obtained. During the latter years of its currency, the patent belonged to an unincorporated company, The Proprietors of the Invention for raising water by fire, whose members included John Meres.
Although its first use was in coal-mining areas, Newcomen's engine was also used for pumping water out of the metal mines in his native West Country, such as the tin mines of Cornwall. By the time of his death, Newcomen and others had installed over a hundred of his engines, not only in the West Country and the Midlands but also in north Wales, near Newcastle and in Cumbria.
The first Newcomen engine in France was installed by John May and John Meres (referred to as John Meyer in France) in 1726. A Newcomen engine installed by the Compagnie d’Anzin at Fresnes in the early 1730s was built by Christophe Mathieu, based on examples installed at Liège and Charleroi in the late 1720s.[1]
Technical details
Newcomen's engine had a boiler in which the steam was generated, usually of the 'haystack' type, situated directly below the cylinder. It produced low pressure steam, all that the current state of boiler construction could cope with.
One side of the beam was attached by a chain to the pump located at the base of the mine, and the chain at the other side suspended a piston within a cylinder. The cylinder was open at the top end, above the piston, to the atmosphere. The piston had a bevelled edge, around which hemp rope, kept in place by metal weights, acted as a primitive seal. Additional sealing was provided by a film of water maintained on top of the piston.
When a valve was opened, steam was admitted from the boiler into the cylinder. After this valve was closed, a valve was opened to allow cold water from the water tank into the cylinder, thus condensing the steam and collapsing the pressure under the piston. The atmospheric pressure above then pushed the piston down in the power stroke. This raised the working parts of the pump, and their weight returned the beam to its original position when the vacuum decayed and steam was readmitted. The steam drove out the condensate (and the air and other gases liberated from the steam) through a one-way 'snifting valve' as the process started all over again.
Early versions used manual operation of the valves to work, but the action was slow enough that this was not a serious concern. Later versions used controls attached to the rocking beam to open and close the valves automatically when the beam reached certain positions. The common myth is that in 1713 a boy named Humphrey Potter, whose duty it was to open and shut the valves of an engine he attended, made the engine self-acting by causing the beam itself to open and close the valves by suitable cords and catches (known as the "potter cord"). This device was simplified by 1718 according to an illustration by Henry Beighton, who showed suspended from the beam a rod called the plugtree, which worked the valves by means of tappets.
By 1725 the engine was in common use in collieries, and it held its place without material change for about three-quarters of a century. Towards the close of its career the atmospheric engine was much improved in its mechanical details by John Smeaton, who built many large engines of this type about the year 1770.
While its main use was pumping water out of mines, the Newcomen engine was also used in some places to pump water to drive machinery, for example refilling the upper pool at Coalbrookdale so that there was more water available to drive the blast furnace blowers, also at Madeley Wood or Bedlam Furnaces and others of the same period in the 1750s. Richard Arkwright, for example, even attempted to use a Newcomen engine to pump water to power a waterwheel.
The main problem with the Newcomen design was that it was very expensive to operate. After the cylinder was cooled to create the vacuum, the cylinder walls were cold enough to condense some of the steam as it was admitted. This meant that a considerable amount of fuel was being used just to heat the cylinder back to the point where the steam would start to fill it again. As the heat losses were related to the surfaces, while useful work related to the volume, increases in the size of the engine increased efficiency. Newcomen engines became larger in time. However, efficiency was a secondary consideration within the context of a colliery, where coal was freely available, and unsaleable coal could be used. Attempts were made to drive machinery by Newcomen engines, but these were unsuccessful, as the single power stroke produced a very jerky motion.
Newcomen's engine was superseded by developments initiated by James Watt. Watt had been asked to repair a model of a Newcomen engine by Glasgow University. A model exaggerated the scale problem of the Newcomen engine, and led him to contemplate improvements. In the Watt steam engine, condensation took place in a separate container, attached to the steam cylinder via a pipe. When a valve on the pipe was opened, the vacuum in the condenser would, in turn, evacuate that part of the cylinder below the piston. This eliminated the heating and cooling of the main cylinder, and dramatically reduced fuel use. Watt also introduced double-acting engines. His improvements led to the acceptance of reciprocating engines with upwards and downwards power strokes more suited to transmitting power to a wheel.
Watt's design, introduced in 1769, did not eliminate Newcomen engines immediately. Watt's vigorous defence of his patents resulted in the desire to avoid royalty payments as far as possible. The expiry of the patents led to a rush to install Watt engines in the 1790s, and Newcomen engines were eclipsed - even in collieries. Probably the last Newcomen-style engine to be used commercially – and the last still remaining on its original site – is at Elsecar, near Barnsley in South Yorkshire.
Notes
Eric Preston writes on 27th February 2012: Newcomen Engine - please see my recent booklet on 'Thomas Newcomen of Dartmouth', by Eric Preston. ISBN 1-899011-27-7, available from Dartmouth Tourist Information Centre. The first successful Newcomen Engine was in 1712 at Conygree, it is thought the Wolverhampton one was never actually installed in 1711. The Newcomen Memorial Engine at Dartmouth dates from 1725 and was moved there in 1963. this can be seen operating, but not with steam.
Series of Articles Published in The Engineer
Below are the links to the articles on the Newcomen Engine as published in The Engineer in 1879.
- (No. I) : The Engineer 1879/06/06.
- (No. II) : The Engineer 1879/06/13.