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James Watt

James Watt Steam engine design was greatly improved in the 1770s by Scottish engineer and inventor James Watt (1736–1819). In his early career, Watt was a maker of mathematical instruments, but he soon developed an interest in steam engines. In those days, Thomas Newcomen’s engines were being used for pumping water out of mines. When given one to repair in around 1763, Watt was struck by how inefficient it was: the engine's cylinder was heated and cooled on every cycle. He began work to improve the design. In partnership with the manufacturer Matthew Boulton (1728–1809), Watt's steam engine would make possible the mechanization of factories and mills—triggering the Industrial Revolution.



 
This diagram shows how Watt's steam engine worked. Valve A opens to release steam from the boiler. Steam enters the cylinder from...Read More >>This diagram shows how Watt's steam engine worked. Valve A opens to release steam from the boiler. Steam enters the cylinder from above, pushing the piston down, along with the beam it is connected to. Valve C opens to release steam from the cylinder to the condenser. Valves A and C then close, while B opens, so steam then enters the cylinder from below. The piston moves up, pushing the beam back up.

Watt's steam engine

James Watt’s first steam engine, patented in 1769, included many improvements over Newcomen’s. It had a separate chamber (the condenser) where the steam was condensed (turned back to liquid), allowing the main cylinder to remain hot all the time. Watt also used steam pressure to force the piston down, rather than relying on atmospheric pressure. This increased the power of the engine. An automatic governor controlled the flow of steam to the cylinder, and so regulated its speed.

The unit of measurement of electrical and mechanical power, the watt, is named in honour of James Watt.

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