Time line of steam engine invention.

1st century AD: Hero of Alexandria describes the aeolipile, as an example of the power of heated air or water. The device consists of a rotating ball spun by steam jets; it produced little power and had no practical application, but is nevertheless the first known device moved by steam pressure. He also describes a way transferring water from one vessel to another using pressure, filling a bucket the weight of which worked tackle to open temple doors, closed again by a deadweight once the water in the bucket had been drawn out by a vacuum caused by cooling of the initial vessel.

1125: In Reims, according to William of Malmesbury, an organ was powered by heated water.

1551: Taqi al-Din Muhammad ibn Ma'ruf describes a steam turbine-like device for rotating a spit.

1601: Giovanni Battista della Porta performs experiments on using steam to create pressure or a vacuum, building simple fountains similar to a percolator.

1606: Jerónimo de Ayanz y Beaumont receives a patent for a steam-powered device for pumping water out of mines.

1615: Salomon de Caus, who had been an engineer and architect under Louis XIII, publishes a book showing a device similar to that of Porta.

1629: Giovanni Branca suggests using a steam turbine device similar to that described by Taqi al-Din but intended to be used to power a series of pestles working in mortars.

1630: David Ramsey is granted a patent for various steam applications, although no description is given and the patent also covers a number of unrelated inventions. He refers to a "fire engine", and this term is used for many years.

1663: Edward Somerset, 2nd Marquis of Worcester, publishes a selection of his inventions. One is a new sort of steam pump, essentially two devices like de Caus', but attached to a single boiler. A key invention is the addition of cooling around the containers to force the steam to condense. This produces a partial vacuum inside the chambers, which is used to draw a volume of water into the containers through a pipe, thus forming a pump. He builds one of very large size into the side of Raglan Castle, apparently the first "industrial scale" steam engine. He has plans to build them for mining, but dies before he can set up his company.

1680: Christiaan Huygens publishes memoirs describing a gunpowder engine that drives a piston. It is historically notable as the first known description of a piston engine.

1698: Thomas Savery introduces a steam pump he calls the Miner's Friend. It is almost certainly a direct copy of Somerset's design. One key improvement is added later, replacing the cold water flow on the outside of the cylinder with a spray directly inside it. A small number of his pumps are built, mostly experimental in nature, but like any system based on suction to lift the water, they have a maximum height of 32 feet (and typically much less). In order to be practical, his design can also use the pressure of additional steam to force the water out the top of the cylinder, allowing the pumps to be "stacked", but many mine owners were afraid of the risk of explosion and avoided this option. (Savery engines were re-introduced in the 1780s to recirculate water to water wheels driving textile mills, especially in periods of drought).

1705: Thomas Newcomen develops the atmospheric engine, which, unlike the Savery pump, employs a piston in a cylinder; the vacuum pulling the piston down to the bottom of the cylinder when water is injected into it. The engine enabled a great increase in pumping height and the draining of deeper mines than possible when using vacuum to pull the water up. Savery holds a patent covering all imagined uses of steam power, so Newcomen and his partner John Calley persuade Savery to join forces with them to exploit their invention until the expiration of the patent in 1733.

1707: Denis Papin publishes a study on steam power, including a number of ideas. One uses a Savery-like engine to lift water onto a water wheel for rotary power. The study also proposes replacing the water of a Savery engine with a piston, which is pulled on by the vacuum in a cylinder after steam inside is condensed, but he was unable to build the device.

1718: Desaguliers introduces an improved version of the Savery engine, which includes safety valves and a two-way valve that operated both the steam and cold water (as opposed to two separate valves). It is not commercially employed.

1720: Leupold designs an engine based on expansion, which he attributes to Papin, in which two cylinders alternately receive steam and then vent to the atmosphere. Although likely a useful design, it appears none were built.

From http://en.wikipedia.org/wiki/Timeline_of_steam_power

 

Exercise 15, p. 15.

From http://opensourceecology.org/wiki/Steam_Engine_Intro

UNIT 2

Exercise 14, p. 28.

Hero of Alexandriawas a Greek mathematician and engineer who was active in his native city of Alexandria,Roman Egypt. Hero published a well recognized description of a steam-powered device called an aeolipile (sometimes called a "Hero engine"). Among his most famous inventions was a windwheel, constituting the earliest instance of wind harnessing on land. Hero also invented many mechanisms for the Greek theater, including an entirely mechanical play almost ten minutes in length, powered by a binary-like system of ropes, knots, and simple machines operated by a rotating cylindrical cogwheel. The sound of thunder was produced by the mechanically-timed dropping of metal balls onto a hidden drum. The force pump was widely used in the Roman world, one application was in a fire-engine. Hero described the construction of the aeolipile which was a rocket-like reaction engine and the first-recorded steam engine. It was created almost two millennia before the industrial revolution. Another engine used air from a closed chamber heated by an altar fire to displace water from a sealed vessel; the water was collected and its weight, pulling on a rope, opened temple doors.

James Watt (1736-1819)was a Scottish inventor and mechanical engineer, born in Greenock, who was renowned for his improvements of the steam engine. In 1765, James Watt while working for the University of Glasgow was assigned the task of repairing a Newcomen engine, which was deemed inefficient but the best steam engine of its time. That started the inventor to work onseveral improvements to Newcomen's design. Most notable was Watt's 1769 patent for a separate condenser connected to a cylinder by a valve. Unlike Newcomen's engine, Watt's design had a condenser that could be cool while the cylinder was hot. The field of application for the invention was greatly widened when Boulton urged Watt to convert the reciprocating motion of the piston to produce rotational power for grinding, weaving and milling. Although a crank seemed the obvious solution to the conversion Watt and Boulton were stymied by a patent for this, whose holder, James Pickard, and associates proposed to cross-license the external condenser. Watt adamantly opposed this and they circumvented the patent by their sun and planet gear in 1781. Over the next six years, he made a number of other improvements and modifications to the steam engine. A double acting engine, in which the steam acted alternately on the two sides of the piston was one. He described methods for working the steam "expansively" (i.e., using steam at pressures well above atmospheric). A compound engine, which connected two or more engines was described. One of these included the use of the steam indicator which produced an informative plot of the pressure in the cylinder against its volume, which he kept as a trade secret. Another important invention, one which Watt was most proud of, was the parallel motion which was essential in double-acting engines as it produced the straight line motion required for the cylinder rod and pump, from the connected rocking beam, whose end moves in a circular arc. A throttle valve to control the power of the engine, and a centrifugal governor, patented in 1788, to keep it from "running away" were very important. These improvements taken together produced an engine which was up to five times as efficient in its use of fuel as the Newcomen engine.

 

Thomas Saver (1650–1715)was an English inventor and engineer, born at Shilstone, Devon, England. He is famous for his invention of the first commercially used steam powered engine. On 2 July 1698 Savery patented an early steam engine, which he claimed that it couldpump water out of mines. Savery's engine had no piston, and no moving parts except from the taps. It was operated by first raising steam in the boiler; the steam was then admitted to the working vessel, allowing it to blow out through a downpipe into the water that was to be raised. When the system was hot and therefore full of steam the tap between the boiler and the working vessel was shut, and if necessary the outside of the vessel was cooled. This made the steam inside it condense, creating a partial vacuum, and atmospheric pressure pushed water up the downpipe until the vessel was full. At this point the tap below the vessel was closed, and the tap between it and the up-pipe opened, and more steam was admitted from the boiler. As the steam pressure built up, it forced the water from the vessel up the up-pipe to the top of the mine. However, his engine had four serious problems. First, every time water was admitted to the working vessel much of the heat was wasted in warming up the water that was being pumped. Secondly, the second stage of the process required high-pressure steam to force the water up, and the engine's soldered joints were barely capable of withstanding high pressure steam and needed frequent repair. Thirdly, although this engine used positive steam pressure to push water up out of the engine (with no theoretical limit to the height to which water could be lifted by a single high-pressure engine) practical and safety considerations meant that in practice, to clear water from a deep mine would have needed a series of moderate-pressure engines all the way from the bottom level to the surface. Fourthly, water was pushed up into the engine only by atmospheric pressure (working against a condensed-steam 'vacuum'), so the engine had to be no more than about 30 feet (9.1 m) above the water level – requiring it to be installed, operated, and maintained far down in the mine.

 

Thomas Newcomen a blacksmith from Dartmouth, England, the engine invented by him in 1712 was known as the "Atmospheric Steam Engine". Thomas Newcomen was hired by Savery for his blacksmithing and iron-forging skills, to forge for Savery's engine. Newcomen was allowed to make a copy of the Savery machine for himself, which he set it up in his own backyard, where he worked on improving the Savery design. Unlike Savery's pump, however, Newcomen used the vacuum to pull on a piston instead of pulling on water directly. The upper end of the cylinder was open to the atmospheric pressure, and when the vacuum formed, the atmospheric pressure above the piston pushed it down into the cylinder. The piston was lubricated by a trickle of water from the same cistern that supplied the cooling water. Further, to improve the cooling effect, he sprayed water directly into the cylinder. The piston was attached by a chain to a large pivoted beam. When the piston pulled the beam, the other side of the beam was pulled upward. This end was attached to a rod that pulled on a series of conventional pump handles in the mine. At the end of this power stroke, the steam valve was reopened, and the weight of the pump rods pulled the beam down, lifting the piston and drawing steam into the cylinder again. Thomas Newcomen and John Calley built an engine that while not a total success, they were able to patent in 1708. It was an engine combining a steam cylinder and piston, surface condensation, a separate boiler, and separate pumps. Also named on the patent was Thomas Savery who at that time held the exclusive rights to use surface condensation. The atmospheric engine, as first designed, had a slow process of condensation by the application of the condensing water to the exterior of the cylinder, to produce the vacuum, caused the strokes of the engine to take place at very long intervals. More improvements were made, which immensely increased the rapidity of condensation. Thomas Newcomen's first engine produced 6 or 8 strokes a minute and he improved that to 10 or 12 strokes.

 

Richard Trevithick (13 April 1771 – 22 April 1833) was a British inventor and mining engineer from Cornwall, UK.His most significant contribution was to the development of the first high-pressure steam engine. He also built the first full-scale working railway steam locomotive. On 21 February 1804 the world's first locomotive-hauled railway journey took place as Trevithick's unnamed steam locomotive hauled a train along the tramway. As his experience grew, he realised that improvements in boiler technology now permitted the safe production of high-pressure steam, which could move a piston in a steam engine on its own account, instead of using pressure near to atmospheric in a condensing engine. Trevithick was the first to make high-pressure steam work in England in 1799. Not only would a high-pressure steam engine eliminate the condenser, but it would allow the use of a smaller cylinder, saving space and weight. He reasoned that his engine could now be more compact, lighter and small enough to carry its own weight even with a carriage attached.

From http://en.wikipedia.org

 

Exercise 16, p. 29.

From http://en.wikipedia.org

 

UNIT 3

Exercise 16, p. 45.

Text 1