Newcomen atmospheric engine
The atmospheric engine was invented by Thomas Newcomen in 1712, and is sometimes referred to as the Newcomen fire engine or Newcomen engine. The engine was operated by condensing steam being drawn into the cylinder, thereby creating a partial vacuum which allowed atmospheric pressure to push the piston into the cylinder. It is significant as the first practical device to harness steam to produce mechanical work. Newcomen engines were used throughout Britain and Europe, principally to pump water out of mines. Hundreds were constructed during the 18th century. James Watt's later engine design was an improved version of the Newcomen engine that roughly doubled fuel efficiency. Many atmospheric engines were converted to the Watt design. As a result, Watt is today better known than Newcomen in relation to the origin of the steam engine.
Precursors
Prior to Newcomen, a number of small steam devices of various sorts had been made, but most were essentially novelties. Around 1600, a number of experimenters used steam to power small fountains working like a coffee percolator. First, a container was filled with water via a pipe, which extended through the top of the container to nearly the bottom. The bottom of the pipe would be submerged in the water, making the container airtight. The container was then heated to make the water boil. The steam generated pressurized the container, but the inner pipe, immersed at the bottom by liquid, and lacking an airtight seal at top, remained at a lower pressure; expanding steam forced the water at the bottom of the container into and up the pipe to spurt out of a nozzle on top. These devices had limited effectiveness but illustrated the principle's viability.In 1606, the Spaniard, Jerónimo de Ayanz y Beaumont, demonstrated and was granted a patent for a steam-powered water pump. The pump was successfully used to drain the inundated mines of Guadalcanal, Spain.
In 1662, Edward Somerset, 2nd Marquess of Worcester, published a book containing several ideas he had been working on. One was for a steam-powered pump to supply water to fountains; the device alternately used a partial vacuum and steam pressure. Two containers were alternately filled with steam, then sprayed with cold water making the steam within condense; this produced a partial vacuum that would draw water through a pipe up from a well to the container. A fresh charge of steam under pressure then drove the water from the container up another pipe to a higher-level header before that steam condensed and the cycle repeated. By working the two containers alternately, the delivery rate to the header tank could be increased.
Savery's "Miner's Friend"
In 1698, Thomas Savery patented a steam-powered pump he called the "Miner's Friend", combining both the expansive power of steam and the vacuum formed through condensation. The process of cooling and creating the vacuum was fairly slow, so Savery later added an external cold water spray to quickly cool the steam.Savery's invention cannot be strictly regarded as the first steam "engine" since it had no moving parts and 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.
A theoretical problem with Savery's device stemmed from the fact that a vacuum could only raise water to a maximum height of about ; to this could be added another, or so, raised by steam pressure. This was insufficient to pump water out of a mine. In Savery's pamphlet, he suggests setting the boiler and containers on a ledge in the mineshaft and even a series of two or more pumps for deeper levels. Obviously, these were inconvenient solutions and some sort of mechanical pump working at surface level – one that lifted the water directly instead of "sucking" it up – was desirable. Such pumps were common already, powered by horses, but required a vertical reciprocating drive that Savery's system did not provide. The more practical problem concerned having a boiler operating under pressure, as demonstrated when the boiler of an engine at Wednesbury exploded, perhaps in 1705. Engines based on the Savery design, albeit enhanced over time, were installed and used as returning engines, raising water to boost the supply to existing water wheels, examples are known in Manchester and Lancashire.
Denis Papin's experimental steam cylinder and piston
in his monumental work gives a full quotation of Denis Papin's paper published in 1690 in Acta eruditorum at Leipzig, entitled "Nouvelle méthode pour obtenir à bas prix des forces considérables". It seems that the idea came to Papin while working with Robert Boyle at the Royal Society in London. Papin describes first pouring a small quantity of water into the bottom of a vertical cylinder, inserting a piston on a rod and after first evacuating the air below the piston, placing a fire beneath the cylinder to boil the water away and create enough steam pressure to raise the piston to the top end of the cylinder. The piston was then temporarily locked in the upper position by a spring catch engaging a notch in the rod. The fire was then removed, allowing the cylinder to cool, which condensed steam back into water, thus creating a vacuum beneath the piston. To the end of the piston rod was attached a cord passing over two pulleys and a weight hung down from the cord's end. Upon releasing the catch, the piston was sharply drawn down to the bottom of the cylinder by the pressure differential between the atmosphere and the created vacuum; enough force was thus generated to raise a weight. "Several of his papers were put before the Royal Society between 1707 and 1712 a description of his 1690 atmospheric steam engine, similar to that built and put into use by Thomas Newcomen in 1712."Introduction and spread
Newcomen took forward Papin's experiment and made it workable, although little information exists as to exactly how this came about. The main problem to which Papin had given no solution was how to make the action repeatable at regular intervals. The way forward was to provide, as Savery had, a boiler capable of ensuring the continuity of the supply of steam to the cylinder, providing the vacuum power stroke by condensing the steam, and disposing of the water once it had been condensed. The power piston was hung by chains from the end of a rocking beam. Unlike Savery's device, pumping was entirely mechanical, the work of the steam engine being to lift a weighted rod slung from the opposite extremity of the rocking beam. The rod descended the mine shaft by gravity and drove a force pump, or pole pump inside the mineshaft. The suction stroke of the pump was only for the length of the upward stroke, there consequently was no longer the 30-foot restriction of a vacuum pump and water could be forced up a column from far greater depths. The boiler supplied the steam at extremely low pressure and was at first located immediately beneath the power cylinder but could also be placed behind a separating wall with a connecting steam pipe. Making all this work needed the skill of a practical engineer; Newcomen's trade as an "ironmonger" or metal merchant would have given him significant practical knowledge of what materials would be suitable for such an engine and brought him into contact with people having even more detailed knowledge.The earliest examples for which reliable records exist were two engines in the Black Country, of which the more famous was that erected in 1712 at the Conygree Coalworks in Bloomfield Road Tipton now the site of "The Angle Ring Company Limited", Tipton. This is generally accepted as the first successful Newcomen engine and followed 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.
Another Newcomen engine was in Cornwall. Its location is uncertain, but it is known that one was in operation at Wheal Vor mine in 1715.
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. Since Savery's patent had not yet run out, Newcomen was forced to come to an arrangement with Savery and operate under the latter's patent, as 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.
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. Small numbers were built in other European countries, including in France, Belgium, Spain, and Hungary, also at Dannemora, Sweden. Evidence of the use of a Newcomen Steam Engine associated with early coal mines was found in 2010 in Midlothian, VA.
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Technical details
Components
Although based on simple principles, Newcomen's engine was rather complex and showed signs of incremental development, problems being empirically addressed as they arose. It consisted of a boiler A, usually a haystack boiler, situated directly below the cylinder. This produced large quantities of very low pressure steam, no more than – the maximum allowable pressure for a boiler that in earlier versions was made of copper with a domed top of lead and later entirely assembled from small riveted iron plates. The action of the engine was transmitted through a rocking "Great balanced Beam", the fulcrum E of which rested on the very solid end-gable wall of the purpose-built engine house with the pump side projecting outside of the building, the engine being located in-house. The pump rods were slung by a chain from the arch-head F of the great beam. From the in-house arch-head D was suspended a piston P working in a cylinder B, the top end of which was open to the atmosphere above the piston and the bottom end closed, apart from the short admission pipe connecting the cylinder to the boiler.Early cylinders were made of cast brass, but cast iron was soon found more effective and much cheaper to produce. The first to use cast iron was reported to be the engine installed at Hawarden in Wales between 1714 and 1715. Among the foundries producing and boring iron Newcomen engine cylinders were Coalbrookdale and later the Carron ironworks. The piston was initially surrounded by a seal in the form of a leather ring, but as the cylinder bore was finished by hand and not absolutely true, a layer of water had to be constantly maintained on top of the piston. Later soft hemp rope packing was used with iron weights above to keep it in place. The piston was insulated from the steam, which it would otherwise condense, by bolting wood to the underside. Installed high up in the engine house was a water tank C fed by a small in-house pump slung from a smaller arch-head. The header tank supplied cold water under pressure via a stand-pipe for condensing the steam in the cylinder with a small branch supplying the cylinder-sealing water; at each top stroke of the piston excess warm sealing water overflowed down two pipes, one to the in-house well and the other to feed the boiler by gravity.