The aegis & intelligencer. [volume] (Bel Air, Md.) 1864-1923, 1896-08-21
COOLING TOWERS.
AcLEVER, SIMPLE, BUT VERY VALUA-
BILE YANKEE DEVICE.


BY Its Use Fuel In Steammaking Is Saved.
Hot Water From the Condenser Met by
an Air Blast and Cooled by Evaporation
on a Very Simple Principle.
At some of the large power plants in
and near New York the eye Of the visitor
or the passerby is attracted by new and
unusual fcature-a circular steel tower,
looking like the tall stand pipe of some
high level water system. 1t is, however.
no tank There is water in it, but indeed
this is pcrpctually leaking out-in fact,
the percolation of the water downward
from top to bottom is what gives the de-
vice its unique value. 1t is the cooling
tower Of self cooling condenser-one of
those numerous labor and power saving
Yankee inventions that have placed us
where we now stand as . nation of invent
ors and engineers.
Every one knows that there are two
principal types of steam engines-the non
condensing, in which the exhaust steam
escapes into the air, making the hoarse,
putting sound SO familiar in the locomo-
tive and the steam tug, and the condens-
ing, IN which it is delivered into n con-
denser, where it is cooled down and turn
ed back into water. In the former typo
the piston has to work against the pres
sure of the GtmoSphere-about 10 pounds
to the square inch. In the latter it has
only to overcome the pressure of the vapor
in the condenser, which is much less, as
the condensation of the steam causes a
partial vacuum; hence the condensing en-
zine is much the moro economical of the
two, saving fully % per cent of the steam
and hence of the fuel-required for the
other.
Why, then, are not condensing engines
universally employed: Sometimes be-
cause the use Of the condcnsing device is
not practicable. as on locomotive. Still
oftener because it requires an unlimited
supply OF water. Cold water is the means
employed to condense the steam and as it
becomes warmer in the process it cannot
be used over again; hence engines that are
not situated near large water supp4y-op
a river bank, for instance-cannOt avail
themselves of the condensing principle and
profit by its fuel saving power. And even
where a river is near, land on its bank is
so often so Inuch more expensive that the
manufacturer prefers to go farther away
where he can buy ut a lower price, even if
he has to use Il noncondcnsing engine.
But why not cool the heated condenser
water and use it again? This has been
tried over and over, more or less ciumsily
and ineffectively, and it is exactly what is
done successfully in the cooling towers al
ready mentioned. Methods previously in
use employ shallow ponds to cool the
water by surface evaporation, but these are
out of the question in a large city-or pans
on the roof, which are awkward and take
up room. The cooling tower, which has
satisfactorily solved the problem and offers
to the manufacturer the welcome chance of
saving Il large proportion of his fuel, has
been in use for some time in primitive
and crude form in tho southern states,
where the condenser water was allowed to
cool by trickling through mass of brush.
Later, in Germany, the same result was
effected by allowing it to blow over a nest
of pipes. In the perfected form the steel
tower is packed with layer on layer OF
vitrified tiles, set up on end. Through
these, from the top to tho bottom of the
tower, the heated condenser water trio.
kles, while n powerful air blast is blown
upward through it from = rotary fan at
the base When the water has reached the
bottom, it is cool enough to use again in
the condenser \ little of it-from q!
to 3 per cent-Eas cvaporatcd in the proc
ess, but this loss is more than made up
by the condensed exhaust steam that is
added as it does its work in the condenser.
In passing through the tower the water
is cooled from about 100 degrees to at least
the temperature of the outside air, chiefly
by the evaporation induced by the air blast
that passes through the tiling. The prin-
ciple is exactly the same as when one cools
his moist hand by blowing on it. Strange
ly enough, the cooling is greater in sum-
mer than in winter, for, though i'll winter
the air is colder, it is much nearer the
point of saturati0n and will take up very
little evaporation, and evaporation is the
chief thing in the cooling.
Direct escape of the heat by contact
with the air blast and by radiation through
the steel sides of the tower helps, but il is
relatively unimportant So, with the aid
of this device. the condensing engine, with
its great economy, is today within the
reach of every manufacturer in the land,
instead of perhaps half of them The opera
ton of the tower is inexpensive, as the
cost OF working is only that of pumping
the water to the top and operating the fan,
and this is slight compared with the say.
ing that results from using condensation.
The towers take up little room. They
vary in size from % feet i'll height by
feet in diameter, which is suitable for 40
horsepower engine, to one 80 feet i'll height
by rs feet in diameter for an engine of
l, 800 horsepower. One of the towers has
for some time been in use at the Grand Av-
enue Edison electric lighting station in
Brooklyn, in connection with 500 horse
power engine.
1t must not be imagined, however, that
the usefulness of a cooling tower stops
with its employment as described above
As its name implies, it may be used any
where where water is to be deprived of
superfluous heat For instance, in the
manufacture of ice, where water is frozen
by the evaporation of hquctied ammonia
The ammonia, which has been heated in
the process OF liqucfaction by compreSsioR
is cooled by means of water, and with the
aid of a cooling tower this water can be
made ready for use II second time.
Like nearly all really serviccable devices
the cooling tower is provokingly simple
Amy one might think of it-only nobody
did, until Yankee ingenuity took n hint
from the crude devices of yesterday and
put hundreds of misunderstanding or
potentially-into the pockets of American
manufacturers, miners and others who
have occasion to use the steam engine
Philadelphia Press.