I'm going to toss a name in the ring for one of the top spots in the inventor class.
3.10 James Watt Inventor
The brilliant Scot who transformed the steam engine into an efficient device that was instrumental in ushering in the Industrial Revolution. He did not invent the steam engine, rather he took an inefficient design and made it drastically more practical. The steam engine as it was when he began his work on it used boiling water and a stream of cold water to produce steam. This process cooled the boiling water which then had to be re-heated, wasting as much as 80% of the heat used in the process. He developed two gigantic advancements that revolutionized the world. His most important patent was the external condenser which allowed the source water to stay at it's heated temperature in a separate chamber. He then continued to improve the engine by adding valves to create a two way stroke, doubling the already multiply expanding power of the engine. He later started manufacturing and selling them with a financial partner in a "manufactory" which became the "factory".
Numerous other patents followed, some of which like Edison were most likely from his employees, that eventually led to the steam locomotive. Regardless of their origin, those controversial (but undisputed) patents were based on the newly efficient design of the steam engine. He coined the term "horsepower" and the "watt" as a unit of power was named after him.
Over the next six years, he made a number of other improvements and modifications to the steam engine. A
double acting engine, in which the steam acted alternately on the two sides of the piston was one. A
throttle valve to control the power of the engine, and a
centrifugal governor to keep it from "running away" were very important. 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.
James Watt's improvements to the steam engine transformed the Newcomen engine, which had hardly changed for fifty years, and initiated a series of improvements in generating and applying power, which transformed the world of work, and was a key innovation of the Industrial Revolution. The importance of the invention can hardly be overstated--it gave us the modern world. A key feature of it was that it brought the engine out of the remote coal fields into factories where many mechanics, engineers, and even tinkerers were exposed to its virtues and limitations. It was a platform for generations of inventors to improve. It was clear to many that higher pressures produced in improved boilers would produce engines having even higher efficiency, and would lead to the revolution in transportation that was soon embodied in the locomotive and steamboat. It made possible the construction of new factories that, since they were not dependent on water power, could work the year round, and could be placed almost anywhere. Work was moved out of the cottages, resulting in economies of scale. Capital could work more efficiently, and manufacturing productivity greatly improved. It made possible the cascade of new sorts of machine tools that could be used to produce better machines, including that most remarkable of all of them, the Watt steam engine.
His inventions weren't limited to the steam engine either:
Watt continued to invent other things before and during his semi-retirement. He invented a new method of measuring distances by telescope, a device for copying letters, improvements in the oil lamp, a steam mangle and a machine for copying sculptures.