Boulton and Watt steam engine (Powerhouse Museum)
Encyclopedia
The Boulton and Watt steam engine preserved in the Powerhouse Museum in Sydney, Australia, built in 1785, is one of the first rotative steam engine
s ever built, and is the oldest surviving. A rotative engine is a type of beam engine
where the reciprocating motion
of the beam is converted to rotary motion
, producing a continuous power source suitable for driving machinery.
This engine was designed by the mechanical engineer James Watt
, manufactured for the firm Boulton & Watt and originally installed in a brewery
in London. On decommissioning in 1887 it was sent to Australia's Powerhouse Museum
(then known as the Technological, Industrial and Sanitary Museum) and has since been restored to full working order.
in 1784 to replace a horse wheel
at the Chiswell Street premises of his London brewery
. It was installed in 1785, the second steam engine to be installed in a brewery, and enabled Whitbread to become the largest brewer in Britain. The horse wheel was retained for many years, serving as a backup in case the steam engine broke down.
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The drive gear of the engine, still evident today, was connected to a series of wooden line shaft
s which drove machinery within the brewery
. Connected machinery included rollers to crush malt
; an Archimedes screw, that lifted the crushed malt into a hopper
; a hoist
, for lifting items into the building; a three-piston pump
, for pumping beer; and a stirrer within a vat. There was also a reciprocating pump connected to the engine's beam, used to pump water from a well
to a tank on the roof of the brewery.
In a marketing coup for both the brewer and the engine's manufacturer, King George III
and Queen Charlotte
visited the brewery on 24 May 1787. The engine remained in service for 102 years, until 1887.
The engine made its way to the Powerhouse Museum (then known as the Technological, Industrial and Sanitary Museum) through Archibald Liversidge
, an English-born chemist, scientist and academic at the University of Sydney, who was a trustee of the Museum. Liversidge was in London in 1887, at the time of the engine's decommissioning, and when he heard that the engine was to be scrapped he asked whether it could be donated to the museum. Whitbread & Co agreed on condition that the engine be set up and used for educational purposes.
Subsequently the engine was dismantled and shipped to Sydney on the sailing ship Patriarch. For shipping purposes, the large flywheel was divided into two halves. While the flywheel's rim could be unbolted, the hub with attached spokes had to be drilled though and rejoined after shipping. A shortage of funds meant the engine was kept in storage for several years. Eventually the engine was erected in its own engine house, behind the main building at the museum's old Harris Street premises. During the 1920s or 1930s, an electric motor was added so that people could see the engine in motion. During the 1980s the Technology Restoration Society was formed in order to raise funds for the engine's restoration. Restoration took place at the Museum's Castle Hill site. The engine, restored to steaming condition, was installed in the new Powerhouse Museum in 1988. Today the engine is sometimes operated as part of the Museum's Steam Revolution exhibition, steam being provided by the Museum's central boiler
.
The engine has a 0.64 metres (25.2 in) diameter piston
with a 1.8 metres (5.9 ft) long stroke, driven by a mean effective pressure
of 70 kilopascals (10.2 psi). Its top speed is 20 revolutions per minute
(rpm) of the flywheel. In the engine's youth, it had a maximum power output of approximately 26 kW. It underwent a series of alterations in 1795, converting it from single-acting to double-acting; it was alleged at the time that this conversion improved its power to 52 kW, but the Powerhouse Museum claims this is false. A centrifugal governor
, which moderates the level of steam produced if the engine begins to overload was added some years after this, and beam and main driving rod, both originally of wood, were replaced in sand-cast iron.
Apart from its age, the engine is notable in that it embodies the four innovations which made Boulton & Watt's engines a significant driver of the Industrial Revolution
. The first is a separate condenser, which increases the efficiency of the engine by allowing the main cylinder to remain hot at all times. The second is the parallel motion
, which converts the up-and-down motion of the piston into the arcing motion of the beam, whilst maintaining a rigid connection. The rigid connection allowed the engine to be double-acting, meaning the piston could push as well as pull the beam. Third is the centrifugal governor
, used to automatically regulate the speed of the engine. Finally the sun and planet gear
convert the reciprocating motion of the beam into a rotating motion, which can be used to drive rotating machinery.
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...
s ever built, and is the oldest surviving. A rotative engine is a type of beam engine
Beam engine
A beam engine is a type of steam engine where a pivoted overhead beam is used to apply the force from a vertical piston to a vertical connecting rod. This configuration, with the engine directly driving a pump, was first used by Thomas Newcomen around 1705 to remove water from mines in Cornwall...
where the reciprocating motion
Reciprocating motion
Reciprocating motion, also called reciprocation, is a repetitive up-and-down or back-and-forth motion. It is found in a wide range of mechanisms, including reciprocating engines and pumps. The two opposite motions that comprise a single reciprocation cycle are called strokes...
of the beam is converted to rotary motion
Rotation around a fixed axis
Rotation around a fixed axis is a special case of rotational motion. The fixed axis hypothesis exclude the possibility of a moving axis, and cannot describe such phenomena as wobbling or precession. According to Euler's rotation theorem, simultaneous rotation around more than one axis at the same...
, producing a continuous power source suitable for driving machinery.
This engine was designed by the mechanical engineer 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...
, manufactured for the firm Boulton & Watt and originally installed in a brewery
Brewery
A brewery is a dedicated building for the making of beer, though beer can be made at home, and has been for much of beer's history. A company which makes beer is called either a brewery or a brewing company....
in London. On decommissioning in 1887 it was sent to Australia's 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...
(then known as the Technological, Industrial and Sanitary Museum) and has since been restored to full working order.
History
The engine was ordered by Samuel WhitbreadSamuel Whitbread (brewer)
Samuel Whitbread was an English brewer and Member of Parliament. In 1742, he established a brewery that in 1799 became Whitbread & Co Ltd.-Biography:...
in 1784 to replace a horse wheel
Horse mill
A horse mill is a mill that uses a horse as the power source. Any milling process can be powered in this way, but the most frequent use of animal power in horse mills was for grinding grain and pumping water. Other animals used for powering mills include dogs, donkeys and oxen. Engines powered by...
at the Chiswell Street premises of his London brewery
Whitbread
Whitbread PLC is a global hotel, coffee shop and restaurant company headquartered in Dunstable, United Kingdom. Its largest division is Premier Inn, which is the largest hotel brand in the UK with around 580 hotels and over 40,000 rooms. Its Costa Coffee chain has around 1,600 stores across 25...
. It was installed in 1785, the second steam engine to be installed in a brewery, and enabled Whitbread to become the largest brewer in Britain. The horse wheel was retained for many years, serving as a backup in case the steam engine broke down.
Line shaft
A line shaft is a power transmission system used extensively during the Industrial Revolution. Prior to the widespread use of electric motors small enough to be connected directly to each piece of machinery, line shafting was used to distribute power from a large central power source to machinery...
s which drove machinery within the brewery
Brewery
A brewery is a dedicated building for the making of beer, though beer can be made at home, and has been for much of beer's history. A company which makes beer is called either a brewery or a brewing company....
. Connected machinery included rollers to crush malt
Malt
Malt is germinated cereal grains that have been dried in a process known as "malting". The grains are made to germinate by soaking in water, and are then halted from germinating further by drying with hot air...
; an Archimedes screw, that lifted the crushed malt into a hopper
Hopper
Hopper may refer to:-Mechanical parts:* A general term for a chute with additional width and depth for temporary storage* Hopper , a large container used for dust collection* Part of a combine harvester...
; a hoist
Hoist
Hoist may refer to:*Hoist , a machine for lifting loads*hoist controller, a machine for raising and lowering goods or personnel by means of a cable*Hydraulic hooklift hoist, another machine* Hoist , another machine...
, for lifting items into the building; a three-piston pump
Pump
A pump is a device used to move fluids, such as liquids, gases or slurries.A pump displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps...
, for pumping beer; and a stirrer within a vat. There was also a reciprocating pump connected to the engine's beam, used to pump water from a well
Water well
A water well is an excavation or structure created in the ground by digging, driving, boring or drilling to access groundwater in underground aquifers. The well water is drawn by an electric submersible pump, a trash pump, a vertical turbine pump, a handpump or a mechanical pump...
to a tank on the roof of the brewery.
In a marketing coup for both the brewer and the engine's manufacturer, King George III
George III of the United Kingdom
George III was King of Great Britain and King of Ireland from 25 October 1760 until the union of these two countries on 1 January 1801, after which he was King of the United Kingdom of Great Britain and Ireland until his death...
and Queen Charlotte
Charlotte of Mecklenburg-Strelitz
Charlotte of Mecklenburg-Strelitz was the Queen consort of the United Kingdom as the wife of King George III...
visited the brewery on 24 May 1787. The engine remained in service for 102 years, until 1887.
The engine made its way to the Powerhouse Museum (then known as the Technological, Industrial and Sanitary Museum) through Archibald Liversidge
Archibald Liversidge
Archibald Liversidge, FRS, was an English-born Australian chemist and founder of the Australasian Association for the Advancement of Science.-Early life:...
, an English-born chemist, scientist and academic at the University of Sydney, who was a trustee of the Museum. Liversidge was in London in 1887, at the time of the engine's decommissioning, and when he heard that the engine was to be scrapped he asked whether it could be donated to the museum. Whitbread & Co agreed on condition that the engine be set up and used for educational purposes.
Subsequently the engine was dismantled and shipped to Sydney on the sailing ship Patriarch. For shipping purposes, the large flywheel was divided into two halves. While the flywheel's rim could be unbolted, the hub with attached spokes had to be drilled though and rejoined after shipping. A shortage of funds meant the engine was kept in storage for several years. Eventually the engine was erected in its own engine house, behind the main building at the museum's old Harris Street premises. During the 1920s or 1930s, an electric motor was added so that people could see the engine in motion. During the 1980s the Technology Restoration Society was formed in order to raise funds for the engine's restoration. Restoration took place at the Museum's Castle Hill site. The engine, restored to steaming condition, was installed in the new Powerhouse Museum in 1988. Today the engine is sometimes operated as part of the Museum's Steam Revolution exhibition, steam being provided by the Museum's central boiler
Boiler
A boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications.-Materials:...
.
Technical specifications
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...
with a 1.8 metres (5.9 ft) long stroke, driven by a mean effective pressure
Mean effective pressure
The mean effective pressure is a quantity related to the operation of an reciprocating engine and is a valuable measure of an engine's capacity to do work that is independent of engine displacement. When quoted as an indicated mean effective pressure or imep , it may be thought of as the average...
of 70 kilopascals (10.2 psi). Its top speed is 20 revolutions per minute
Revolutions per minute
Revolutions per minute is a measure of the frequency of a rotation. It annotates the number of full rotations completed in one minute around a fixed axis...
(rpm) of the flywheel. In the engine's youth, it had a maximum power output of approximately 26 kW. It underwent a series of alterations in 1795, converting it from single-acting to double-acting; it was alleged at the time that this conversion improved its power to 52 kW, but the Powerhouse Museum claims this is false. 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 moderates the level of steam produced if the engine begins to overload was added some years after this, and beam and main driving rod, both originally of wood, were replaced in sand-cast iron.
Apart from its age, the engine is notable in that it embodies the four innovations which made Boulton & Watt's engines a significant driver of 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...
. The first is a separate condenser, which increases the efficiency of the engine by allowing the main cylinder to remain hot at all times. The second is the 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...
, which converts the up-and-down motion of the piston into the arcing motion of the beam, whilst maintaining a rigid connection. The rigid connection allowed the engine to be double-acting, meaning the piston could push as well as pull the beam. Third is the 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...
, used to automatically regulate the speed of the engine. Finally the 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....
convert the reciprocating motion of the beam into a rotating motion, which can be used to drive rotating machinery.