POWER
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Key Facts
For many years water was the only
significant source of power to drive
machinery. Mills were driven by a wheel, powered by the flow of a
stream running past and turning the mechanism. It was not until the
late 17th century when Thomas Savery, a military engineer, devised a
system that he called the “atmospheric engine” that powerful pumps were
available. Pumps were needed to raise water from mines to prevent
flooding. By pumping out ground water it was possible to reach much
lower depths and exploit new mineral veins.
Savery used atmospheric pressure to
drive his pump by filling the
cylinder with steam then rapidly cooling it by running water over the
surface of the engine. The steam quickly condensed with a massive
reduction of pressure that pulled water out of the mine shaft. The
system was inefficient and dangerous because it was liable to explode,
so blacksmith Thomas Newcomen designed a new version that was more
reliable and it was first installed in the Earl of Dudley’s limestone
mines below Dudley Castle (West Midlands) in 1712.
Newcomen’s engine was heavy and slow,
but efficient, and it was adopted
by mines all over the UK but in 1765 Scottish instrument maker James
Watt realised that cooling the steam for each engine stroke wasted
energy. He devised a way to keep the steam hot and to shift it to
opposite sides of a piston and so produced an engine that had a
powerful double stroke. His early efforts were dogged by technical
difficulties but he was eventually taken on by Birmingham
‘toy’
manufacturer Matthew Boulton who created the massive Soho Foundry so
that Watt could perfect his machine.
Watt later developed an addition to
his engine that enabled the
straight stroke of the piston to be turned to circular motion. The
rotary adapter revolutionised industry and made it possible for the
first time to drive production machinery by steam. The Industrial
Revolution finally had a power source equal to the ideas of its leaders
and factories sprang up all over the country to manufacture goods.
Formerly cottage industries were moved to centres of mass production
with the mechanisation of all kinds of crafts from spinning and weaving
to pottery and metalwork.