milling and steam power pioneer

Oliver Evans was born in Newport, Delaware, on September 13, 1755. He was apprenticed to a wheelwright and wagon maker as a teenager, and studied math and science on the side.

When he was 22, Evans was hired to produce cards for combing wool. Making the teeth for one card was slow and repetitive, so Evans designed a machine to produce card teeth. Meant to turn out 500 teeth a minute, it actually produced 1,500; and, the mass-produced teeth proved superior to the hand-made ones.

In 1780, Evans went into the flour-milling business with two of his brothers. Seeking increased efficiency, he harnessed the energy of a water wheel and used shafts, gears, and belts to propel mill machinery. In his design, elevators were used to raise materials, conveyors carried material sideways, and chutes carried materials down from the upper floors. These inventions essentially automated the flour-milling process to the point that the mill could be run by one person. And, by reducing the amount of human contact with the grain and flour, the mill turned out a much cleaner and better quality flour.

In the late 1780s, the legislatures of Maryland and Pennsylvania granted Evans the exclusive right to the application of these improvements. In 1790, the U.S. Congress granted him patents for his flour-milling inventions -- making Evans the third person to be granted a patent in the United States. Within a few years, Evans had licensed his technology to over 100 users.

left: diagram of Evans' mill
center: diagram of some of the machinery in Evans' mill design
right: diagram of the 'hopper boy'

Evans next turned his attention to steam power. James Watt had already invented the low-pressure steam engine, but Evans' idea was for a high-pressure engine. In the Watt engine, steam was condensed in the cylinder, creating a vacuum so that atmospheric pressure pushed the piston down. In Evans' engine, the steam was introduced into the cylinder under high pressure and used to push the piston down directly. He also placed the cylinder and the crankshaft at the same end instead of at opposite ends, greatly reducing the overall weight.

diagram of Evans' steam engine

In 1803 and 1804 the Philadelphia Board of Health commissioned Evans to build a steam-powered dredger to raise mud from the Schuylkill River. It was powered to move over land on wheels and in the river by means of a paddle wheel. The Orukter Amphibolos ("amphibious vehicle") made its debut in 1805. The machine broke down on its first trial and Evans wanted to scrap it. But his mill workers repaired the dredge at their own expense, and it was successfully used for several years to scoop up mud around Philadelphia's docks.

Evans' steam-powered dredging machine

Evans hoped to adapt his design to move vehicles on rails of wood or iron, but he was a little far ahead of his time; the country's first commercial railroad track was not laid until the early 1830's.

In 1807, Evans founded the Mars Iron Works in Philadelphia; he opened another factory in Pittsburgh in 1811. These two factories built customized steam engines and boilers for mills, steamboats, and factories.

Evans was the author of two books: The Young Millwright and Miller's Guide (1797) and The Abortion of the Young Engineer's Guide (1805).

Oliver Evans died in New York City on May 13, 1819.

SOURCE
Engines of Our Ingenuity www.uh.edu/engines/epi285.htm

SEE ALSO
James Watt

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This page was last updated on 05/15/2017.