During the American gold rush (1848-1855), people flocked from all over the world to California with dreams of finding great wealth. Lester Pelton (1829- 1908) of Ohio was one of these migrants, but it was not in gold that he found success. It was with his free- jet water turbine, which he first patented in 1880, that he found fame and fortune.
Gold mining was becoming a large-scale industry and required ever-increasing amounts of power. As firewood supplies dwindled, steam power became very expensive and mining companies looked for an alternative energy source in the creeks and waterfalls surrounding the mines.
In 1866 Samuel Knight invented a water turbine that replaced the paddles of water wheels—like those used in rivers to power flour mills—with cups to catch jets of water directed from above. While watching a misaligned turbine, Pelton noticed that the water ran down the edge of the cup rather than hitting the middle, making the wheel turn faster. This is because the amount of force generated by the water jet increases with the distance over which it is applied. To take advantage of this, Pelton split the cups In two with a metal wedge so that the water would hit the wedge and move down on either side and thus travel further. Pelton's design—the Pelton wheel—was more than 90 percent efficient, an improvement of about 14 percent on its closest rival.
The Pelton wheel remained the standard for decades and was the basis for later water turbines. These are still manufactured today, and many Pelton wheels still function around the world. Maybe the search for renewable energy sources will spark a revival in this method of water power.
