James Watt

The most famous British engineer, a great improver, most definitely NOT the inventor of the steamengine.james watt

He was born the 19th of January 1736 in Greenock, son of a builder/contractor. During his youth and during all his life he was frequently sick, depressed and hypochondric.

Not science but natural philosophy. The term ‘engineer’ was unknown

In James Watt youth there were two types of men involved in the practice of steamengines, the natural philosphers and the practical craftsmen. Fortunately Watt had the talents of both.

When he was a child his father provided him with tools and james quickly became a fastidious craftsman. Lateron he was trained as an instrumentmaker. These skills have helped him all his life.

In 1761 he experimented with high pressure steam, but he was very afraid of a bursting boiler. So he skipped the idea of high (moderate) steampressure and did so for the rest of his life. High pressure had to wait for Richard Trevithick who succesfully implemented ‘strong’ steam.

In 1757 he was asked to have a look at a broken model of a Newcomen engine. He got it running again, but it was then that he wondered why its performance was so disappointing.

He discussed this matter with some scientists who explained the item of ‘latent’ heat to him. Latent heat (or enthalpy) is energy that is required to chance from one state of aggregation to another, for instance from water to steam. This amount of energy is very significant and Watt realised that the Newcomen-engine wasted a lot of energy here.

It was in 1765 that he thought of the separate condensor. Because of this condensor it was no longer necessary to cool the cilinder each stroke down under condensationtemperature and then heat it up again. By keeping the cilinder hot he achieved efficiencyimprovements of 5 times!

Later improvements included the substitution of steam for air above the piston and for heating up the cilinder by a steamjacket. This all to keep the cilinder as hot as possible.

On the 5th of January 1769 Watt was granted his long awaited patent.

In 1775 Watt offered the right to manufacture his engines to Matthew Boulton. Boulton owned a metal manufactory. From then on his engines were manufactured and sold under the name ‘Boulton and Watt’. Actually Boulton’s factory only made the valves, the valve-chests and regulating gear, all other parts were produced elsewhere or locally.

In 1774 Wilkinson had patented a new boring machine. With this machine he was capable of boring steam engine cilinders truly circular and parallel. It put an end to the pistontroubles with leaking packings.

In 1783 Watt build his first double acting rotating engine.

The engines of James Watt aren’t steamengines in the modern sense of the term since they derive their power from the atmospheric pressure. This pressure can do its work after a vacuum generated by condensing steam