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Watt steam engine

Watt steam engine

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The Watt steam engine was the first type of steam engine
Steam engine
A steam engine is a heat engine that performs mechanical work using steam as its working fluid.Steam engines are external combustion engines, where the working fluid is separate from the combustion products. Non-combustion heat sources such as solar power, nuclear power or geothermal energy may be...

 to make use of steam at a pressure just above atmospheric
Atmospheric pressure
Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...

 to drive the piston helped by a partial vacuum. Improving on the design of the 1712 Newcomen engine
Newcomen steam engine
The atmospheric engine invented by Thomas Newcomen in 1712, today referred to as a Newcomen steam 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,...

, the Watt steam engine, developed sporadically from 1763 to 1775, was the next great step in the development of the steam engine. Offering a dramatic increase in fuel efficiency
Fuel efficiency
Fuel efficiency is a form of thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuel into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is...

, the new design replaced Newcomen engines in areas where coal was expensive, and then went on to be used in the place of most natural power sources such as wind and water. James Watt
James Watt
James Watt, FRS, FRSE was a Scottish inventor and mechanical engineer whose improvements to the Newcomen steam engine were fundamental to the changes brought by the Industrial Revolution in both his native Great Britain and the rest of the world.While working as an instrument maker at the...

's design became synonymous with steam engines, due in no small part to his business partner, Matthew Boulton
Matthew Boulton
Matthew Boulton, FRS was an English manufacturer and business partner of Scottish engineer James Watt. In the final quarter of the 18th century the partnership installed hundreds of Boulton & Watt steam engines, which were a great advance on the state of the art, making possible the...

.

Introduction


In 1698, the English
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 mechanical designer Thomas Savery
Thomas Savery
Thomas Savery was an English inventor, born at Shilstone, a manor house near Modbury, Devon, England.-Career:Savery became a military engineer, rising to the rank of Captain by 1702, and spent his free time performing experiments in mechanics...

 invented a steam pumping appliance that drew water directly from a well by a vacuum, then sent it up to a higher level by steam pressure. The appliance was also proposed for draining mines
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...

, but its pumping height was limited, making this impracticable. It consumed a large amount of fuel compared with later engines.


The solution to draining deep mines was found by Thomas Newcomen
Thomas Newcomen
Thomas Newcomen was an ironmonger by trade and a Baptist lay preacher by calling. He was born in Dartmouth, Devon, England, near a part of the country noted for its tin mines. Flooding was a major problem, limiting the depth at which the mineral could be mined...

 who developed an "atmospheric" engine also working on the vacuum principle. It employed a cylinder containing a movable piston connected by a chain to one end of a rocking beam that worked a mechanical lift pump from its opposite end. The top of the steam cylinder was open to the atmosphere. At the end of each stroke, steam was introduced into the cylinder below the piston, followed by water. This water condensed the steam and created a partial vacuum below the piston, drawing it down and thus raising the opposite end of the beam.

The Newcomen engine was more powerful than the Savery engine. For the first time water could be raised from a depth of over 150 feet. The first example from 1711 was able to replace a team of 500 horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...

s that had been used to pump out the mine. Seventy-five Newcomen pumping engines were installed at mines in Britain, France, Holland, Sweden and Russia. In the next fifty years only a few small changes were made to the engine design.

While Newcomen engines brought practical benefits, they were inefficient in terms of the use of energy to power them. The system of alternately sending jets of steam, then cold water into the cylinder meant that the walls of the cylinder were alternately heated, then cooled each stroke. As each charge of steam was introduced, it would continue condensing until the cylinder approached working temperature once again. So at each stroke part of the potential of the steam was lost.

Separate condenser



A Scottish
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

 instrument maker, James Watt
James Watt
James Watt, FRS, FRSE was a Scottish inventor and mechanical engineer whose improvements to the Newcomen steam engine were fundamental to the changes brought by the Industrial Revolution in both his native Great Britain and the rest of the world.While working as an instrument maker at the...

, was given the job in 1763 of repairing a model Newcomen engine for the University of Glasgow
University of Glasgow
The University of Glasgow is the fourth-oldest university in the English-speaking world and one of Scotland's four ancient universities. Located in Glasgow, the university was founded in 1451 and is presently one of seventeen British higher education institutions ranked amongst the top 100 of the...

, and noted how inefficient it was.

In 1765 Watt conceived the idea of a separate condensation
Condensation
Condensation is the change of the physical state of matter from gaseous phase into liquid phase, and is the reverse of vaporization. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition....

 chamber. Watt's idea was to equip the engine with a second, small cylinder, connected to the main one. In Watt's design, the cold water was injected only into the condensation chamber. This type of condenser is known as a jet condenser. Because the chambers were connected, this caused condensation without significant loss of heat. The condenser remained cold and under less atmospheric pressure
Atmospheric pressure
Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...

 than the cylinder, while the cylinder remained hot. When the piston
Piston
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from...

, propelled by steam, reached the top of the cylinder
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...

, the steam inlet valve closed and the valve controlling the passage to the condenser
Condenser (heat transfer)
In systems involving heat transfer, a condenser is a device or unit used to condense a substance from its gaseous to its liquid state, typically by cooling it. In so doing, the latent heat is given up by the substance, and will transfer to the condenser coolant...

 opened. External atmospheric pressure pushed the piston towards the condenser.

A further improvement to the system of condensation was to dispense with the jet of cold water, and cool the condenser by immersing it in a cold water tank. This type of condenser is known as a surface condenser.

At each stroke the warm condensate was drawn off and sent up to a hot well by a vacuum pump which also helped to evacuate the steam from under the power cylinder. The still-warm condensate was recycled as feedwater for the boiler.

Watt's next improvement to the Newcomen design was to increase the power of the engine by sealing the top of the cylinder and injecting low-pressure steam into the upper part of the cylinder, instead of relying on atmospheric pressure. The power of the low-pressure steam would assist the vacuum created by the condensation, increasing the power of the down stroke, and the speed of the engine.

These improvements led to the fully developed version of 1775 that actually went into production.

The partnership of Matthew Boulton and James Watt


The separate condenser showed dramatic potential for improvements on the Newcomen engine but Watt was still discouraged by seemingly insurmountable problems before a marketable engine could be perfected. It was only after entering into partnership with Matthew Boulton
Matthew Boulton
Matthew Boulton, FRS was an English manufacturer and business partner of Scottish engineer James Watt. In the final quarter of the 18th century the partnership installed hundreds of Boulton & Watt steam engines, which were a great advance on the state of the art, making possible the...

 that such became reality. Watt told Boulton about his ideas on improving the engine, and Boulton, an avid entrepreneur
Entrepreneur
An entrepreneur is an owner or manager of a business enterprise who makes money through risk and initiative.The term was originally a loanword from French and was first defined by the Irish-French economist Richard Cantillon. Entrepreneur in English is a term applied to a person who is willing to...

, agreed to fund development of a test engine at Soho
Soho, Birmingham
Soho is an area in north west Birmingham, approximately 2 miles from the City Centre on the A41, which until 1911 formed part of Handsworth District. Soho is also a ward within the council constituency of Ladywood...

, near Birmingham
Birmingham
Birmingham is a city and metropolitan borough in the West Midlands of England. It is the most populous British city outside the capital London, with a population of 1,036,900 , and lies at the heart of the West Midlands conurbation, the second most populous urban area in the United Kingdom with a...

. At last Watt had access to facilities and the practical experience of craftsmen who were soon able to get the first engine working. As fully developed, it used about 75% less fuel than a similar Newcomen one.

In 1775, Watt designed two large engines: one for the Bloomfield Colliery at Tipton
Tipton
Tipton is a town in the Sandwell borough of the West Midlands, England, with a population of around 47,000. Tipton is located about halfway between Birmingham and Wolverhampton. It is a part of the West Midlands conurbation and is a part of the Black Country....

, completed in March 1776, and one for John Wilkinson
John Wilkinson (industrialist)
John "Iron-Mad" Wilkinson was an English industrialist who pioneered the use and manufacture of cast iron and cast-iron goods in the Industrial Revolution.-Early life:...

's ironworks at Willey, Shropshire
Willey, Shropshire
Willey is a small village south west of the town of Broseley, Shropshire, England, within the civil parish of Barrow. It is made up of about 4 farms and the majority of land is owned and leased by the Forrester family...

, which was at work the following month. A third engine, at Stratford-le-Bow
Stratford, London
Stratford is a place in the London Borough of Newham, England. It is located east northeast of Charing Cross and is one of the major centres identified in the London Plan. It was historically an agrarian settlement in the ancient parish of West Ham, which transformed into an industrial suburb...

 in east London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

, was also working that summer.

Watt had tried unsuccessfully for several years to have an accurately bored cylinder for his steam engines, and was forced to used hammered iron, which was out of round and caused leakage past the piston. The following quotation is from Roe (1916):

"When [John] Smeaton
John Smeaton
John Smeaton, FRS, was an English civil engineer responsible for the design of bridges, canals, harbours and lighthouses. He was also a capable mechanical engineer and an eminent physicist...

 saw the first engine he reported to the Society of Engineers that 'neither the tools nor the workmen existed who could manufacture such a complex machine with sufficient precision' "


In 1774 John Wilkinson
John Wilkinson
John Wilkinson may refer to:* John Wilkinson * John Wilkinson , British industrialist who suggested the use of iron for many roles where other materials had previously been used...

 invented a boring machine with the shaft, which held the cutting tool, supported on both ends, extending through the cylinder, unlike the then used cantilevered borers. With this machine he was able to bore the 50 inch diameter (1.27 meter) cylinder for Boulton & Watt
Boulton and Watt
The firm of Boulton & Watt was initially a partnership between Matthew Boulton and James Watt.-The engine partnership:The partnership was formed in 1775 to exploit Watt's patent for a steam engine with a separate condenser. This made much more efficient use of its fuel than the older Newcomen engine...

's first commercial engine, and was given an exclusive contract for the provision of cylinders.

Boulton and Watt
Boulton and Watt
The firm of Boulton & Watt was initially a partnership between Matthew Boulton and James Watt.-The engine partnership:The partnership was formed in 1775 to exploit Watt's patent for a steam engine with a separate condenser. This made much more efficient use of its fuel than the older Newcomen engine...

's practice was to help mine-owners and other customers to build engines, supplying men to erect them and some specialised parts. However, they mainly profited from their patent by charging a licence fee to the engine owners, based on the cost of the fuel they saved. The greater fuel-efficiency of their engines meant that they were most attractive in areas where fuel was expensive, particularly Cornwall
Cornwall
Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...

, for which three engines were ordered in 1777, for Wheal Busy
Wheal Busy
Wheal Busy, sometimes called Great Wheal Busy and in its early years known as Chacewater Mine, was a metalliferous mine half way between Redruth and Truro in the Gwennap mining area of Cornwall, England. During the 18th century the mine produced enormous amounts of copper ore and was very wealthy,...

, Ting Tang mine, and Chacewater mines.

Later improvements



Driving the engines by the pressure differential between low-pressure steam and a partial vacuum raised the possibility of reciprocating engine
Reciprocating engine
A reciprocating engine, also often known as a piston engine, is a heat engine that uses one or more reciprocating pistons to convert pressure into a rotating motion. This article describes the common features of all types...

 development. An arrangement of valves could admit steam to either end, or connect either end with the condenser. Consequently, the direction of the power stroke might be reversed. The resulting double action
Steam engine
A steam engine is a heat engine that performs mechanical work using steam as its working fluid.Steam engines are external combustion engines, where the working fluid is separate from the combustion products. Non-combustion heat sources such as solar power, nuclear power or geothermal energy may be...

 gave a very even movement to the piston.

Before the development of the double acting piston, the linkage to the beam and the piston rod had been by means of a chain, which meant that power could only be applied in one direction, by pulling. This was effective in engines that were used for pumping water, but the double action of the piston meant that it could push as well as pull. This was not possible as long as the beam and the rod were connected by a chain. Furthermore, it was not possible to connect the piston rod of the sealed cylinder directly to the beam, because while the rod moved vertically in a straight line, the beam was pivoted at its centre, with each side inscribing an arc. To bridge the conflicting actions of the beam and the piston, Watt developed his parallel motion
Parallel motion
The parallel motion is a mechanical linkage invented by the Scottish engineer James Watt in 1784 for his double-acting steam engine.In previous engines built by Newcomen and Watt, the piston pulled one end of the walking beam downwards during the power stroke using a chain, and the weight of the...

. This masterpiece of engineering uses a four bar linkage
Linkage (mechanical)
A mechanical linkage is an assembly of bodies connected together to manage forces and movement. The movement of a body, or link, is studied using geometry so the link is considered to be rigid. The connections between links are modeled as providing ideal movement, pure rotation or sliding for...

 coupled with a pantograph
Pantograph
A pantograph is a mechanical linkage connected in a special manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical movements in a second pen...

 to produce the required straight line motion much more cheaply than if he had used a slider type of linkage. He was very proud of his solution.

Having the beam connected to the piston shaft by a means that applied force alternately in both directions also meant that is was possible to use the motion of the beam to turn a wheel. The most simple solution to transforming the action of the beam into a rotating motion was to connect the beam to a wheel by a crank
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...

, but because another party had patent rights on the use of the crank, Watt was obliged to come up with another solution. He adopted the epicyclic sun and planet gear
Sun and planet gear
The sun and planet gear was a method of converting reciprocal motion to rotary motion and was utilised in a reciprocating steam engine....

 system suggested by an employee William Murdoch
William Murdoch
William Murdoch was a Scottish engineer and long-term inventor.Murdoch was employed by the firm of Boulton and Watt and worked for them in Cornwall, as a steam engine erector for ten years, spending most of the rest of his life in Birmingham, England.He was the inventor of the oscillating steam...

, only later reverting, once the patent rights had expired, to the more familiar crank seen on most engines today. The main wheel attached to the crank was large and heavy, serving as a fly wheel which, once set in motion, by its momentum maintained a constant power and smoothed the action of the alternating strokes. To its rotating central shaft, belts and gears could be attached to drive a great variety of machinery.

Because factory machinery needed to operate at a constant speed, Watt linked a steam regulator valve to a centrifugal governor
Centrifugal governor
A centrifugal governor is a specific type of governor that controls the speed of an engine by regulating the amount of fuel admitted, so as to maintain a near constant speed whatever the load or fuel supply conditions...

 which he adapted from those used to automatically control the speed of windmills.

These improvements allowed the steam engine to replace the water wheel
Water wheel
A water wheel is a machine for converting the energy of free-flowing or falling water into useful forms of power. A water wheel consists of a large wooden or metal wheel, with a number of blades or buckets arranged on the outside rim forming the driving surface...

 and horses as the main sources of power for British industry, thereby freeing it from geographical constraints and becoming one of the main drivers in the Industrial Revolution
Industrial Revolution
The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times...

.

Watt was also concerned with fundamental research on the functioning of the steam engine. His most notable measuring device, still in use today, is the Watt indicator incorporating a manometer to measure steam pressure within the cylinder according to the position of the piston, enabling a diagram to be produced representing the pressure of the steam as a function of its volume throughout the cycle.

Preserved Watt engines


The oldest surviving Watt engine is Old Bess
Old Bess (beam engine)
Old Bess is an early beam engine built by the partnership of Boulton and Watt. The engine was constructed in 1777 and worked until 1848.The engine is most obviously known simply for being an early example of an engine built by Boulton and Watt...

 of 1777, now in the Science Museum, London.
The oldest working engine in the world is the Smethwick Engine
Smethwick Engine
The Smethwick Engine is a steam engine made by Boulton and Watt; brought into service in May 1779.Originally, it was one of two engines used to pump water back up to the summit level of the BCN Old Main Line canal at Smethwick, not far from the Soho Foundry where it was made...

, brought into service in May 1779 and now at Thinktank
Thinktank, Birmingham
Thinktank is a science museum in Birmingham, England. Opened in 2001, it succeeded and has several exhibits from the City's Museum of Science and Industry. It is part of the Millennium Point complex.-Building:...

 in Birmingham
Birmingham
Birmingham is a city and metropolitan borough in the West Midlands of England. It is the most populous British city outside the capital London, with a population of 1,036,900 , and lies at the heart of the West Midlands conurbation, the second most populous urban area in the United Kingdom with a...

 (formerly at the now defunct Museum of Science and Industry, Birmingham).
The oldest still in its original engine house and still capable of doing the job for which it was installed is the 1812 Boulton and Watt engine at the Crofton Pumping Station
Crofton Pumping Station
Crofton Pumping Station is a pumping station near the village of Great Bedwyn in the English county of Wiltshire: it supplies the summit pound of the Kennet and Avon Canal with water....

. This was used to pump water for the Kennet and Avon Canal
Kennet and Avon Canal
The Kennet and Avon Canal is a waterway in southern England with an overall length of , made up of two lengths of navigable river linked by a canal. The name is commonly used to refer to the entire length of the navigation rather than solely to the central canal section...

; on certain weekends throughout the year the modern pumps are switched off and the two steam engines at Crofton still perform this function.
The oldest extant rotative steam engine
Boulton and Watt steam engine (Powerhouse Museum)
The Boulton and Watt steam engine preserved in the Powerhouse Museum in Sydney, Australia, built in 1785, is one of the first rotative steam engines ever built, and is the oldest surviving...

 (from 1785, the third rotative engine ever built) is located in the Powerhouse Museum
Powerhouse Museum
The Powerhouse Museum is the major branch of the Museum of Applied Arts and Sciences in Sydney, the other being the historic Sydney Observatory...

 in Sydney, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

.
A Boulton-Watt engine of 1788 may be found in the Science Museum, London
Science museum
A science museum or a science centre is a museum devoted primarily to science. Older science museums tended to concentrate on static displays of objects related to natural history, paleontology, geology, industry and industrial machinery, etc. Modern trends in museology have broadened the range of...

., while an 1817 blowing engine
Blowing engine
A blowing engine is a large stationary steam engine directly coupled to air pumping cylinders. They deliver a very large quantity of air at a pressure lower than an air compressor, but greater than a centrifugal fan....

, formerly used at the Netherton
Netherton, West Midlands
Netherton is a town in the West Midlands within the Metropolitan Borough of Dudley. It lies around south of the town of Dudley and north of Cradley Heath...

 ironworks of M W Grazebrook now decorates Dartmouth Circus, a traffic island at the start of the A38(M) motorway
A38(M) motorway
The A38, also known as the Aston Expressway, is a motorway in Birmingham, England. It is long and was opened on 24 May 1972. It forms part of the much longer A38 route....

 in Birmingham.

The Henry Ford Museum in Dearborn
Dearborn
-Places:In the United States, all named after Henry Dearborn :* Dearborn, Michigan* Dearborn, Missouri* Dearborn County, Indiana* Fort Dearborn * Fort Dearborn , in present-day Odiorne State Park...

, Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....

 houses a Watt rotative engine manufactured in 1788 by Charles Summerfield. This is a full-scale working Boulton-Watt engine. The American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 industrialist Henry Ford
Henry Ford
Henry Ford was an American industrialist, the founder of the Ford Motor Company, and sponsor of the development of the assembly line technique of mass production. His introduction of the Model T automobile revolutionized transportation and American industry...

 moved the engine to Dearborn
Dearborn
-Places:In the United States, all named after Henry Dearborn :* Dearborn, Michigan* Dearborn, Missouri* Dearborn County, Indiana* Fort Dearborn * Fort Dearborn , in present-day Odiorne State Park...

 around 1930.

See also

  • Boulton and Watt
    Boulton and Watt
    The firm of Boulton & Watt was initially a partnership between Matthew Boulton and James Watt.-The engine partnership:The partnership was formed in 1775 to exploit Watt's patent for a steam engine with a separate condenser. This made much more efficient use of its fuel than the older Newcomen engine...

  • Carnot cycle
    Carnot cycle
    The Carnot cycle is a theoretical thermodynamic cycle proposed by Nicolas Léonard Sadi Carnot in 1824 and expanded by Benoit Paul Émile Clapeyron in the 1830s and 40s. It can be shown that it is the most efficient cycle for converting a given amount of thermal energy into work, or conversely,...

  • Heat engine
    Heat engine
    In thermodynamics, a heat engine is a system that performs the conversion of heat or thermal energy to mechanical work. It does this by bringing a working substance from a high temperature state to a lower temperature state. A heat "source" generates thermal energy that brings the working substance...

  • Thermodynamics
    Thermodynamics
    Thermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...

  • James Watt
    James Watt
    James Watt, FRS, FRSE was a Scottish inventor and mechanical engineer whose improvements to the Newcomen steam engine were fundamental to the changes brought by the Industrial Revolution in both his native Great Britain and the rest of the world.While working as an instrument maker at the...

  • Newcomen steam engine
    Newcomen steam engine
    The atmospheric engine invented by Thomas Newcomen in 1712, today referred to as a Newcomen steam 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,...

  • Preserved beam engines

External links