Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1892-02-21
OVER FROM COAL.
ientiStS Believe the High
est Efficiency Has
Been Reached.
IE TRIPLE EXPANSION
Used Upon the Great Grayhounds
of the Atlantic Ocean.
ED OF THE TURBINE ENGINES.
Iew Utilization of the Exhaust to Gen.
crate Electricity.
he TRIPLE EXPANSION
ED OF THE TURBINE ENGINES.
z HISTORY OF BOILER DEVELOPMENT

WRITTEN FOR THE DIsPAToH.1
Tor a good many reasons the most efficient
am engines built are those we find aboard
D. When factory engine can be so i'm
wed as to save 100 tons Of coal q year its
ner increases his profits by the cost OF SO
ch fuel With similar Improvement In
marine engine, the owner saves not only
his coal bill, but he can carry 100 tons more
paving freight Should he seek increase
passenger traffic rather than OF cargo, he
use his former quantum of fuel and add,
rhaps, as much as knot an hour to the
ED of his vessel,
When we learn that the power needed to
We the Majestic or the Teutonic rises to
O0O-horse, it becomes plain that the high
prizes in steam engine practice are held
to the inventors who can reduce the
st outlay these figures represent. De-
tie the iabors of inventors, stimulated as
ey have been by great rewards, even the
st steam engine is a very wasteful con-
vance Suppose We take one of 6O-horse
wer such as may be found in a small
-rvboat, and set it for an hour at the sole
,rk of generating heat by rubbing iron
2tes together, or in any other convenient
". we shall find it yield no more hest
an is given out in burning ten pounds of
cd anthracite coal-about as much fuel SIS
winter furnace of an ordinary New
1rk house will consume in an hour.
Tho Efficiency of the Engine.
We have rule here which works both
lys. SO that, were the heat of our ten
,unds of coal fully converted into power,
should have our 60-horse engine pro-
lied by it for an hour. Were the engine
of the very best type, it would give us
1t one-seventh this duty. That modest
action, therefore, shows how much still
IS before ingenuity in its effort to get work
lt of coal. Since the DAYS of James Watt
e steam engine has been gradually brought
an effectiveness four and half times
eater than he was ever able to realize
ow far this march of advance is likely to
utinue VIII appear as we glance at its
-incipal steps
First, and chiefly, this progress is in
,bted to a steady Improvement in both
i'll and workmanship. Watt was fully
are that economy lay in the use of high
-essures, but he had not boilers strong
Iough, cylinders true enough, or pistons
Cht enough for steam much beyond stmos-
lerlc pressure. As boiler makers and en-
ne builders have become more expert, and
ought new tools of precision to their aid,
cam pressures have constantly increased.
f late years movement in this direction
IS been rapid. Whereas in 1880 marine
lgines rarely ran with steam exceeding 75
)unds pressure, to-day $50 to 200 pounds
not uncommon. 1t is in this increase of
reSsure that the chief gain in the efficiency
the steam engine has been realized.
The Heat to Make Steam.
Steam at 200 pounds requires but little
ore heat for its production than steam at
;, vet about double the duty per pound
n be gotten out of it. With due regard to
her considerations, the smaller furnace
le better. 1t should admit Just air enough
r the combustion of the fuel and no more.
~ excess beyond this quantity takes heat
ON the fire TO be wastefully carried up the
nckestack. And the smaller a furnace the
SIS surface has it for loss of heat by con-
uction and radiation.
In some of the new ocean racers the heat
the chimney gases is applied to warming
le air on its way TO the fire, the delivery
I this air at a temperature of $50 degrees
ahr., instead of say so degrees, effecting a
cry decided saving. If the motion of
oses in the combustion chamber were un-
lscked they would rush out from beneath