J.M. Simpson, Inventor 1876
The typical steam engine, like the modern internal combustion
engine, with its system of cranks and connecting rods, are kinematically
complex and dynamically abhorrent. The soul of the true engineer
yearns for the pure, even rotation. Before the invention of
the steam turbine and the gas turbine, numerous inventors proposed
"rotary engines." This is a particularly elegant one.
The rotating cylinder acts as its own sliding valve to distribute
steam on the two sides of the piston. Moving parts are reduced
toa minimum. When it turns, it purrs.
Cliff Petersen Collection
Photography, Joanne Savio
Curiously enough, we forget that we still live in the age of steam.
We do not see steam locomotives anymore on the railroads, so we
conclude the age of steam is gone. We declare ourselves in a new
age-atomic, space, information, or whatever age the latest discovery
happens to be in. We flip a switch, and power appears as of by magic
under our finger tips.
But how is that electricity produced that toasts our bread, heats
or cools our houses, propels trains and subways, computes and handles
all the electronic data without which banks, stock markets, hospitals,
governments, or any business, large or small, could not operate?
The largest bulk of it is produced by steam. The generators in
power stations producing electricity are powered by steam turbines,
converting to mechanical form the chemical energy stored in coal,
gas, or oil, or the nuclear energy stored in uranium. Without the
steam turbine, none of the large ships would sail, and international
trade would come to a virtual stand-still. Steam is still the muscle.
||Peter Cooper's Tom Thumb
was the first practical steam locomotive built on the American
continent. Successful inventions like these play a minor role
in Cooper's Reminiscences compared to such fanciful
devices as the torpedo ship.
Of course, in the last 150 years since these patents were taken,
some things have changed in the world of steam. Pressures and temperatures
have gone up, strain and corrosion have gone down due to improved
materials. So power and efficiencies have gone up. During World
War II, the proverbial Liberty ship carried 10,OOO T of freight
at 12 knots, developing about 1200 horsepower with their triple
expansion reciprocating engines, like the old fashioned locomotives;
tankers would carry 10.OOOT at 14 knots and develop around 1500
horsepower with turboelectric engines. But in the last 40 years–the
true age of steam–the standard steam turbo-generator set found
in power stations has moved in leaps and bounds from 50 megawatts
in the early 50s to 100 megawatts by the late 50s, 500 megawatts
in the 60s and 1000 megawatts and beyond in the 70s. Meanwhile,
a typical tanker, also propelled by steam, has grown from 25,000T
to 35,000T to 65,000T to 100,000T to 250,000T and beyond.
So, we still need boilers, and steam traps, and steam boiler water
feeders, and pumps. The fundamental ideas are still the same, though
their realizations have evolved. One of these fundamental ideas,
for instance, is that contained in the steam boiler water feeder.
The device is ingenious yet simple: a float operates a valve letting
in the water–very much as in a toilet tank–but it also
operates and regulates the water pump. As the Watt governor on the
steam engine before it, this system incorporates the principle of
the feedback control system, which would take nearly another century
to be clarified and patented by Harold Stephen Black in 1938 (No.
2,102,671 for the Negative Feedback Amplifier).
Since then, of course "feedback" has become a household
word and found its way into telecommunications, computers, weapons,
biomedical devices, not to mention as a concept in science and philosophy.
So at times, beyond the surrealistic shape of an old fashioned
gadget, lies a nugget.