milling and steam
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
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
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.
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
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 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.
Engines of Our Ingenuity
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