Mechanics: The Science of MachineryBond, A. Russell (Alexander Russell)
History
Mechanics: The Science of Machinery
Bond, A. Russell (Alexander Russell)
Machinery; Mechanical engineering; Mechanics
The highest velocity of a wheel is naturally at the periphery and the
advantage of an inflowing turbine such as this is that the water is
traveling at its highest velocity when it strikes the periphery of the
rotor. As it loses its velocity it flows in toward the slower-moving
portions of the rotor. Finally it reaches the center, after giving up
practically all its energy, and falls into the tail pool through a
draft tube at the center of the rotor.
The scroll chambers at Keokuk are thirty-nine feet in diameter and the
draft tubes are eighteen feet in diameter. Water enters the scroll
chambers with a velocity of fourteen feet per second and comes out of
the draft tubes into the tail pool with its velocity cut down to but
four feet per second. Compare this with the velocity of the water jets
at Big Creek!
The current generated at Keokuk goes to St. Louis and surrounding towns
and serves a population of 1,120,000.
Now that we have learned how to transmit electrical power without
serious loss over enormous distances, it is only a question of time
before all the water power in the world is harnessed and put to the
service of man. The power costs nothing after once the plant has been
built; the only expense is that of maintaining the machinery and
keeping it in repair. It is estimated that there is some 200,000,000
horsepower available in this country, but this includes all flowing
water, much of which it would be impracticable, if not almost
impossible, to utilize. However, there is about 60,000,000 horsepower
commercially available, according to the figures of the U. S.
Geological Survey, of which we have developed so far only 6,000,000
horsepower.
The ancients used flowing streams not so much for power purposes as
to lift water to a higher level so that it would flow into their
irrigating ditches. Nowadays, electricity, steam, or air is used for
elevating water, but we have a very ingenious machine which makes
the stream lift a part of itself. This machine is very different in
principle from the old Egyptian noria. It depends upon the kinetic
energy of water in motion. You cannot push a nail into a piece of wood
with a hammer but you can easily drive it in by striking it with the
hammer. As the hammer is swung it acquires what we term kinetic energy
or energy of motion.
SETTING KITCHEN FAUCETS TO WORK
Public-domain text, read in full here on John Shaqi.
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