The morning news. [volume] (Savannah, Ga.) 1887-1900, 1893-12-09

OF them. each Is feet long and 6 feet in
diameter. They burn l25 tons Of coal
week. winter and summer. The seasons
make very little difference, it is always
the same down there.
Now come this way and you will see
how this steam makes the pumps send
water up to the tanks at the top of the
building 5000 gallons of it a minute.
Say they work at full pressure half the
time or four hours day, that gives 100,
600 gallons pumped up about 200 feet,
which means nearly 200 100000 foot
pounds of energy day to run the elev
tors alone.
Not so bad, is it, And the beauty of
it is that in doing this work we use the
water over and over again. pumped Into
the tanks aboEe, then discharged into the
pig tank down here, then through the
pumps again, and so on until we change
it.
''And how does the water run through
the elevators
Il can make that plain to you in two
minutes. You see each elevator has It's
water tank at the top Of the building and
its own hydraulic machine at the bottom.
and the two are connected by an eight
inch iron pipe. That pipe lets the water
from above iuto the three-foot cylinder of
the hydraulic machine. and this water is
pounds to the square inch.
Consequently whenever the water
presses into the cylinder it drives the
piston rod out to its fun length, sixteen
feet with the force of some scores of tons
the calculations is easy if YOU remember
the formula Now this piston rod in
moving pulls apart what you might call
the two blocks of an enormous pulley,
with five wheels in each block.
tho vx-irn
rope which runs around these pulley
wheels goes over u wheel up under the
roof, and then down until it catches the
top of the elevator car. AS there are ten
wheels in the two pullY blocks the END of
the rope with the car ttached travels ten
times as far as the piston rod does. or ten
times sixteen feet, which Is the distance
the elevator travels up and down"
What brings the piston back and the
elevator down.
The changing of this valve where the
iron pipe joins the cylinder. When the
valve is thrown one way the water
presses into the cylinder and up goes the
elevator; when the valve is thrown the
other way the pressure on the piston is
relieved. and the water is discharged into
the tank over there through these pipes.
Then the elevator comes down by its own
weight and that of the passengers.
y
boy when he pulls the cord either way,
and if he should forget to pull the cord
the valve would act automatically, just as
the valves in an engine do.
THE wider the valve is opened, going
either way the faster the car goes, up to
certain point, where. whatever might
happen, even supposing the valve to burst,
a separate attachment, consisting OF an
independent cable. would stop the car by
- hos ysa1I 81 nf
einor. There you have the whole thing
in a nutshell.
And what if the wire rope which holds
the car should break -
The elevator would stop instantly as
it would also if Que of the four ropes-for
there are four, not one should even
stretch. The car would stop because by
reason of a simple device a series of
wedges would be thrown out and grip
the iron frame in which the elevator
slides The heavier the load, the harder
the wedges would hold.
In some elevators the big cylinder is
visible above the floor in a vertical in
stead of a horizontal position with the
pulley wheels scattered along at inter
walls on the way up, as if to give the pas
sengers food for reflection.
In some again there is no water tank at
the top of the building. the requisite
DIRSSu UGlllR oDOalH6Nl OA pumping COIL
pressed air. These are details which con
Germ the elevator men only, and not the
general public. 1t is a splendid achieve
ment to have mastered the main point of
a single system.
One point which l found interesting is
the question of speed. How do these ele-
vators run? How many miles do they
cover day?
This merely depends upon the number
Of
your piston rod. With six. seven or ten
pairs of pulley wheels, instead of five
pairs, the elevators just under considera-
ton would run 30. "a OF 100 feet further
for each stroke of the piston than they do
at present.
The present rate is 500 feet a minute. so
ten pairs of pulleys would give 1000 feet a
minute. twenty pairs would give 2,00O
feet minute, forty pairs 1000 feet a min
ute, and eighty pairs 5000 feet a minute
or over eighty miles an hour. Theoretic-
ally there-is no limit, but as a matter OF
fact. with these constant stoppages at
every floor, the present speed of elevators
is considered as great as will ever become
ADVISABLE
Already in express elevators in Chicago
in such human beehives as the RookerN,
where no stop is made before the tenth or
twelfth floor, elevators are run at the rate
of 500 feet a minute.
The average New York elevator may be
said TO carry twenty passengers; many
carry more, some less, but taking these
figures and allowing 500 complete trips up
and down as the daily work of an elevator
in the busy buildings, then you find each
of these elevators carry 10000 persons
daily when itruns full.
1t is a fact that New York contains Z =
500 elevators at present, including those
IN private houses, and others where the
traffic is comparatively small. II you as
sumo, however, merely to dazzle the
fancy that 5000 Of these are in busy