|Description: Physicist & technician
James Watt was born on January 19th 1736 in Greenock a seaport on the Firth of Clyde. He was a Scottish inventor and mechanical engineer. The changes brought by the Industrial Revolution certainly took advantage of the improvements he made to the steam engine.|
His parents were both Presbyterians and covenanters. His father was a shipwright, ship contractor and owner, and Agnes, his mother, born Muirhead, came from a distinguished family and was well educated.
Watt was mostly schooled at home by his mother and didn’t often go to school. Latin and Greek weren’t his favorite subjects. He preferred legends and lore of the Scottish people and showed dexterity for manual work and an aptitude for mathematics.
At 17, James loses his brother John, who was shipwrecked. When he was 18, his father’s health started deteriorating and his mother died. Watt went to London where he studied instrument-making for a year. Upon his return on Scotland, he settled in Glasgow where he intended to open his own instrument-making business. His application was blocked by the Glasgow Guild of Hammermen for he had not served seven years as an apprentice, although the were no other instrument makers in Scotland.
Fortunately, Watt was offered the opportunity to set up a small workshop in the university of Glasgow, by three professors of the university. It was established in 1758, and Joseph Black, physicist and chemist of the university, became friends with Watt.
In 1764, Watt Married Margaret Miller, his cousin, with whom he had 5 children. Only two made it to adulthood. Margaret died in 1772, when giving birth. He re-married to Ann MacGregor in 1777. She was the daughter of a Glasgow dye-maker. Ann died in 1832.
When John Robinson, a friend of Watt called his attention on steam, Watt starts to experiment. James, who had never seen an operating steam engine, started building a model. He began to read everything in the subject and kept experimenting although his machine didn’t work properly. He then discovered something Black had already discovered the importance of latent heat in understanding the engine.
In 1763, Watt got the university to get back a model Newcomen engine that was in repair in London, and made the repairs himself. It too just barely worked, and after much experimentation he showed that about 80% of the heat of the steam was consumed in heating the cylinder, because the steam in it was condensed by an injected stream of cold water. His critical insight, to cause the steam to condense in a separate chamber apart from the piston, and to maintain the temperature of the cylinder at the same temperature as the injected steam, came finally in 1765 and he soon had a working model.
But Watt’s struggle was only to start. He wanted to produce a full-scale engine, which required funds that were provided by Black. Some capital was given by John Roebuck, the founder of the Carron Iron Works, with whom Watt formed a partnership.
But the result wasn’t as good as expected. Much capital was spent in pursuing the ground-breaking patent, which in those days required an act of parliament. Not having enough money to finance his experiments, Watt had to work as surveyor for eight years. Roebuck went backrupt. Watt then formed a partnership with Matthew Boulton, who at that time owned the Soho foundry works near Birmingham and who had acquired his patent rights. Their partnership was successful and lasted for 25 years.
Watt finally had access to some of the best iron workers in the world. The difficulty of the manufacture of a large cylinder with a tightly fitting piston was solved by John Wilkinson who had developed precision boring techniques for cannon making at Bersham, near Wrexham, North Wales. In1176, the first engines were installed and working in enterprises. These first engines could only produce reciprocating motion and were used for pumps. The next few years, as orders began to pour in, Watt was busy building more machines and installing them in Cornwall for pumping water out of mines.
The field of application of the invention was greatly widened only after Boulton urged Watt to convert the reciprocating motion of the piston to produce rotational power for grinding, weaving and milling. Although a crank seemed the logical and obvious solution to the conversion Watt and Boulton were stymied by a patent for this, whose holder, James Pickard, and associates proposed to cross-license the external condenser. Watt adamantly opposed this and they circumvented the patent by their sun and planet gear in 1781.
Over the years Watt made more improvements to his machine. For instance he created a double acting engine in which the steam acted alternately on the two sides of the piston. He also added a valve to control the power of the engine, and a centrifugal governor to keep it from running away.
He described methods for working the steam expansively. A compound engine, which connected two or more engines was described. Two more patents were granted for these in 1781 and 1782. Numerous other improvements that made for easier manufacture and installation were continually implemented. One of these included the use of the steam indicator which produced an informative plot of the pressure in the cylinder against its volume, which he kept as a trade secret. Another important invention, one of which Watt was most proud of, was the Parallel motion / three-bar linkage which was especially important in double-acting engines as it produced the straight line motion required for the cylinder rod and pump, from the connected rocking beam, whose end moves in a circular arc. This was patented in 1784. These improvements taken together produced an engine which was up to five times as efficient in its use of fuel as the Newcomen engine.
All of Watt’s engines used steam at a very low pressure to prevent boilers from exploding and issues with leaks.
In 1794 was established the Boulton and Watt Company, that manufactured steam engines. The entreprise was working well and in less then 30 years they had produced 1164 steam engines. Boulton proved to be an excellent businessman and both men got along very well and enriched themselves by working together.
In 1800 Watt retired and the partnership with Boulton expired the same year. The men’s sons, Matthed and James Watt Jr, inherited the company and had another partner, William Murdoch, an engineer.
While retiring, Watt kept on inventing things such as a device for copying letters, a new method to measure distances by telescope, improvements on the oil lamp, a machine for copying sculptures and a steam mangle.
With his second wife, he traveled to France and Germany, and he purchased an estate in Wales at Doldowlod House, one mile south of Llanwrthwl, which he much improved.
He died on August 25th, 1819 at his home in Handsworth in England, aged 83.
James Watt was known for being an enthusiastic inventor, who could keep on adding and improving his experiments. He was good at manual work and very good in systematic scientific measurements. He was an important member of the Lunar Society, a dinner club and informal learned society of prominent industrialists, natural philosophers and intellectuals who met regularly in Birmingham, England, between 1765 and 1813.