The Watt steam engine, alternatively known as the Boulton and Watt steam engine, was an early steam engine and was one of the driving forces of the Industrial Revolution. James Watt developed the design sporadically from 1763 to 1775 with support from Matthew Boulton.

The first steam engines, introduced by Thomas New comen in 1712, were of the "atmospheric" design. At the end of the power stroke, the weight of the object being moved by the engine, pulled the piston to the top of the cylinder, as steam was introduced. Then the cylinder was cooled by a spray of water, which caused the steam to condense, forming a partial vacuum in the cylinder. Atmospheric pressure on the top of the piston pushed it down, lifting the work object. Watt noticed that it required significant amounts of heat to warm the cylinder back up to the point where steam could enter the cylinder without immediately condensing. When the cylinder was warm enough that it became filled with steam the next power stroke could commence.

n 1763, James Watt was working as instrument maker at the University of Glasgow when he was assigned the job of repairing a model Newcomen engine and noted how inefficient it was.

In 1765, Watt conceived the idea of equipping the engine with a separate condensation chamber, which he called a "condenser". Because the condenser and the working cylinder were separate, condensation occurred without significant loss of heat from the cylinder. The condenser remained cold and below atmospheric pressure at all times, while the cylinder remained hot at all times.

Watt engine produced by Hathorn, Davey and Co

In the 1880s, Hathorn Davey and Co / Leeds produced a 1 hp / 125 rpm atmospheric engine with external condenser but without steam expansion. It has been argued that this was probably the last commercial atmospheric engine to be manufactured. As an atmospheric engine, it did not have a pressurized boiler. It was intended for small businesses

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Angelina Pearson

Journal Coordinator