James Watt Biography
Inventor of Steam Engine
Posted on February 9, 2010 by Jamie Slaughter, with 10179 views
James Watt, born in 1736 in Greenock, Scotland was a thin child with a passion for mathematics. He also learned carpentry from his father in his early years. His father predominantly worked in shipbuilding and he taught James about quadrants, compasses and telescopes and various other equipment which could be found on ships. From this knowledge, stemmed the desire to become an instrument maker.
In 1754, Watt travelled to Glasgow, Scotland to undertake specialist training under the guidance of Robert Dick. Dick recommended Watt to travel to London for training and Watt accepted his guidance. Watt remained in London for two weeks, trying to seek an apprenticeship. Unfortunately, every instrument making job required a fully trained applicant or as a trainee to serve a minimum seven year apprenticeship.
There was one man who bent the rules somewhat. John Morgan employed Watt on a small wage for one year, after realising the potential of Watt. In 1755, Watt accepted this offer and within only two months had exceeded Morgan's previous apprentice. Watt would work 10 hour days, eager to keep learning more, but with little pay, his health suffered, not helped by the conditions of the workshop.
In 1756, Watt had completed his one year apprenticeship and moved back to Glasgow. Watt's talents were noted by the University, encouraging them to set up a new position called "Mathematical Instrument Maker to the University", where Watt was given his own workshop on the University campus. Watt soon began to realise the fierce competition in this industry and therefore moved onto making musical instruments. In 1758, an architect allowed him to open his own shop in the middle of Glasgow, and his business began to gradually grow, to the extent where he took on apprentices of his own, late in 1763. Despite the progress made, Watt remained in debt.
Watt's breakthrough began in 1763, when Professor John Anderson presented a problem to Watt for him to investigate. The University wanted to know why the Newcomen pumps required so much steam to operate. The model had a clear problem, being that it would halt after a few strokes. Watt quickly realised that the problem was due to the undersized boiler which couldn't offer enough steam to maintain the reheating of the cylinders.
Watt was intrigued by this problem, and began experimenting as to how he could condense the steam without cooling the cylinder. This problem troubled him for months, during which he learned everything about steam and worked with Professor Black to discuss the properties of steam and the latent heat of vaporization. In May, 1765, Watt experienced his breakthrough, 2 years after he began his endeavour. Watt described this moment as follows:
"I had gone to take a walk on a fine Sabbath afternoon, early in 1765. I had entered the green by the gate at the foot of Charlotte Street and had passed the old washing-house. I was thinking upon the engine at the time, and had gone as far as the herd's house, when the idea came into my mind that as steam was an elastic body it would rush into a vacuum, and if a communication were made between the cylinder and an exhausted vessel it would rush into it, and might be there condensed without cooling the cylinder. I then saw that I must get rid of the condensed steam and injection-water if I used a jet as in Newcomen's engine. Two ways of doing this occurred to me. First, the water might be run off by a descending pipe, if an offlet could be got at the depth of thirty-five or thirty-six feet, and any air might be extracted by a small pump. The second was to make the pump large enough to extract both water and air. . . . I had not walked farther than the golf-house when the whole thing was arranged in my mind."
Watt introduced a separate condenser, in which the vapour would rush inside, allowing the steam cylinder to be pulled to a vacuum whilst at all times remaining hot.
Watt did not work on Sundays, but first thing on Monday morning he was back to the shop to carry out his experiment, and test his idea. He constructed a provisional piston and condenser using a brass syringe, and proceeded to fill the syringe with steam. The condenser pumped out the air and cooled it, to Watt's delight.
At the age of 29, Watt realised the importance of his breakthrough, yet it would be 11 further years until his invention was put into practice. Watt was able to manufacture a working engine, which he patented in 1769. Watt was introduced to Matthew Boulton, who saw further opportunities for the new idea and was adamant that he could sell the invention. Without any deal being able to be made, Watt left the shop and took to surveying. Boulton and Watt shared similar personalities, and this began a brilliant partnership. Watt soon moved to Birmingham to join Boulton's shop, where a host of the best craftsmen all worked together.
The Bentley Mining Company began their newest piece of equipment named the Boulton-Watt engine, in March, 1776. The company had abandoned a Newcomen engine to embark on the Boulton-Watt engine.
A reporter at the scene stated:
"From the first Moment of its setting to Work, it made about 14 to 15 Strokes per Minute, and emptied the Engine Pit (which is about 90 Feet deep and stood 57 Feet high in Water) in less than an hour". From "Aris's Birmingham Gazette, March 11, 1776.
The engine used a quarter of the steam of the Newcomen engines, and was a complete success. Watt became deeply involved in setting up pumps and maintaining the business at Cornwall mines.
In June, 1871, Boulton wrote to Watt:
"The people in London, Manchester and Birmingham are steam mill mad. I don't mean to hurry you, but I think in the course of a month or two, we should determine to take out a patent for certain methods of producing rotative motion. There is no other Cornwall to be found, and the most likely line for the consumption of our engines is the application of them to mills which is certainly an extensive field" (Sproule, Ann James Watt, Exley Publications, Herts, UK, 1992)
Watt once again set about developing a new idea. A way in which he could convert reciprocating motion of the piston to rotating motion. He invented the sun and planet gear system, an improvement on an existing patented crankshaft. The sun and gear system allowed the rotative wheel to revolve more than once per stroke of a piston.
A sawmill ordered an engine which could replace 12 horses, which Watt calculated was enough to lift 33,000 pounds, thus creating the unit of hp.
By the turn of the century, 84 British cotton mills used the Boulton and Watt engine, as did flour mills and wool mills. Watt finally earned the success and fame which he most certainly deserved.
Watt's contributions to the world, earned him great respect, with the unit of power, the "Watt" named after him.