The waterwheel is an ancient device
that uses flowing or falling water to create power by means of a set of
paddles mounted around a wheel. The force of the water moved the paddles,
and the consequent rotation of the wheel is transmitted to machinery via
the shaft of the wheel. The first reference to its use dates back to about
4000 B.C., where, in a poem by an early Greek writer, Antipater, it tells
about the freedom from the toil of young women who operated small handmills
to grind corn. They were used for crop irrigation, grinding grains, supply
drinking water to villages and later to drive sawmills, pumps, forge bellows,
tilt-hammers, trip hammers, and to power textile mills. They were probably
the first method of creating mechanical energy that replaced humans and
There are three main kinds of waterwheels.
One kind is the horizontal waterwheel, in which water flows from an aqueduct
and the forward action of the water turns the wheel. Another kind of waterwheel
is the overshot vertical waterwheel, in which water floes from an aqueduct
and the gravity of the water turns the wheel. The last kind is the undershot
vertical waterwheel, a large vertical waterwheel placed in a stream is
turned by the river's motion.
The first waterwheels can be described
as a grindstone mounted atop a vertical shaft whose vaned or paddled lower
end dipped into a swift stream, the wheel was horizontal. As early as the
first century, the horizontal waterwheel, which is terribly inefficient
in transferring the power of the current to the milling mechanism, was
being replaced by waterwheels of the vertical design.
Waterwheels were most often used
to power different types of mills. A waterwheel and mill combination is
called a watermill. An early horizontal-wheeled watermill used for grinding
grain in Greece was the called Norse Mill. In Syria, the watermills were
called "noriahs". They were used for running mills to process cotton into
A modern invention based on the same
principles as the waterwheel is called the hydraulic turbine.
The turbine is a rotary engine that uses the flow of fluid (either
gas or liquid) to turn a shaft that drives machinery. Hydraulic turbines
are used in hydroelectric power stations. Flowing or falling water strikes
a series of blades or buckets attached around a shaft. The shaft then rotates
and the motion drives the rotor of an electric generator.
On May 17, 1839, Lorenzo Adkins patented a
A history of waterwheels, includes
diagrams of how waterwheels work.
Of the three distinct types of water
mills, the simplest and probably the earliest was a vertical wheel with
paddles on which the force of the stream acted. Next was the horizontal
wheel used for driving a millstone through a vertical shaft attached directly
to the wheel. Third was the geared mill driven by a vertical waterwheel
with a horizontal shaft.
Turbines and the Beginnings of Hydroelectricity
illustration National Army Corp source
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