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Steam Engine
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Who will look away
when there’s an engine chugging past? There are very few who
have outgrown a fascination for engines and trains. The crowds
at rail museums should be proof enough. The engine still holds
a great fascination for people. As with all things that have
brought about significant changes in our lives and living, the
rail engine too began humbly, as the chugging steam engine. It
would not be an exaggeration to say that aeroplane and the car
are refinements of the steam engine. For, they all work on the
same principle – convert burning fuel into mechanical energy
on a large scale.
The earliest steam
engines were powered by wood; the later ones were powered by
coal. The invention of the steam engine was one of the
greatest boons to mankind. Its invention meant freedom from
dependence on beasts of burden, for one thing. Secondly, it
did improve speed, speed in transportation of goods. Its
effect was most appreciated during the Industrial Revolution.
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Contrary to
popular belief, James Watt, the person credited with the invention
of the steam engine, was not inspired by watching steam lift off a
lid on a kettle. In fact, a story goes that Watt was inspired when
he was repairing a Newcomen engine for the University of Glasgow, in
May 1765. To understand this, we first we need to look at the
earlier versions of the engine.
The steam
engine is a classic example of an invention that came about in
stages. An English engineer, Thomas Savery, first developed a water
pump that used steam from a boiler for its power. Savery obtained
permission to work on the idea; however, his engine design was not a
success as far as utility was concerned. The idea was improvised
upon by an English blacksmith, Thomas Newcomen in 1712.
Newcomen’s
device was also used primarily to pump water from coal mines. Steam
was condensed in their cylinders, creating a partial vacuum beneath
the piston. The atmospheric air pressure acting on the upper surface
of the piston would then force it downwards, on a working stroke.
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A Steam Engine |
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However,
Scottish engineer James Watt, realized that a large amount of heat
was being wasted by successfully heating the cylinder to fill it
with steam. He came up with the solution of using a separate
condenser, which, he said could be connected to the cylinder through
a valve. He also suggested that the condenser could be kept cool,
while the cylinder could be kept hot. His machine was patented in
1769, but it was a few years before it became practically available
for sale as an engine.
James Watt
made other improvisations such as oil lubrication and insulation. He
also designed a system of gears for effecting the up-and-down motion
of the steam-driven piston into rotary motion. His first double
acting engine was introduced in 1783.
Watt’s
engine proved to a blessing in more ways than just adding speed to
movement and transportation. It gave independence to factories from
their dependence on water power and gave a huge advantage to nations
with ready supplies of coal. Britain’s coal reserves fuelled the
expansion of the British Empire in the eighteenth and nineteenth
centuries. Railroad trains pulled by steam powered engines played a
huge role in industrialization and trade.
Compared to
today’s engines, Watt’s engine perhaps appears primitive, but it was
Watt who laid the firm foundation for inventions being used today
and for the inventions of tomorrow.
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