A story gives the credit for this improvement to an
inventive valve boy who wanted to play with his friends. In 1712,
the mining industry used this steam engine to pump water out of
mine-shafts which had flooded. These engines were also used to
supply water to reservoirs locks at canals, and drinking water
facilities in towns. One such engine developed power equivalent to
fifty horses working at one sixth the cost. It was the first
automatic machine since the clock.
Then James Watt invented the steam engine which used steam as a
force acting on the piston. Watt made his living making scientific
instruments for Glasgow University. Around 1764, he was fixing one
of Newcomen's engines belonging to the university, when he saw its
inefficiencies, such as the loss of heat when the cylinder was
cooled. He saved this heat energy by having the steam condensed in
another vessel distinct but connected to the cylinder. This
condenser was kept constantly cool by cold water. So the condensed
steam was pumped back into the boiler and it circulated
continuously, thus obviating the need for constant resupply of
water. In order to avoid the necessity of using water to keep the
piston air-tight, and also to prevent the air from cooling the
cylinder during the descent of the piston, he used the expansion
of the steam to push the piston instead of atmospheric pressure.
Then, in order to expand the use of the steam engine beyond that
of a pump, he converted the oscillating motion of the beam into
rotary motion.
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