Daily inter mountain. [volume] (Butte, Mont.) 1881-1901, 1899-04-22
COMPRESSED AIR
AS MOTIVE POWER

The Introduction of compressed air as
the motive power on certain of the cross !
town lines in New York, which occurred
less than a month ago, has done much
to increase the interest in this class of
motor. AS the compressed air motors
have been looked upon as somewhat
visionary in their nature by the general
public the announcement that they We're
to be used in the New York streets came
in the nature of a surprise.
To those who lave kept in touch with
this line of thought. however, there was
nothing astonishing in the announcement
Tor during the past two years the COM
pressed air motors lave been improved to
such a degree that, in point OF economy
at least, they compare favorably with the
other and better known motors.
The history of the development of the
motive powers from the day Of the first
steam locomotive up to the present time,
when the compressed air motor may be
said to have been proved a success, is an
interesting subject of study. More than
fifty years ago Brunel, the great inventor,
conceived the idea of making use of COM
pressed air and he was SO confident that
he was or the track of the greatest dis
covery of the age that he built a rail-
way in England several miles in length
and equipped it for compressed air, with
power stations n conduits between the
rails. His system was to ave the COM
pressed air forced into the conduit into
which a piston, attached to the car by
means of a plow, was placed. 1t was in
tended that this should slide along and
furnish the motive power but the whole
scheme was a failure.
During the next half century repeated
efforts were made to solve the compressed
air problem but none succeeded as there
was always a serious loss of power due
to the fact that a large portion of the en-
ergy expended in compressing the air
was transformed into heat, which suisse
quently was lost by radiation. Another
trouble that could not be overcome was
that when the compressed air was util-
lied in motors it's expansion was accom-
panied by a reduction of temperature
which produced accumulations of ice
sufficient to choke the exhaust.
The repeated failures along this limo
have tended to discourage those whose
interest in this phase of invention was
not of the most vital character and the
progress that has been made has, there
fore, been almost unnOticed. The expert
ments that have been made during the
past few years, however, have unques-
%tionably solved the problem for now com
pressed air motors, of single as we'll as Of
compound expansion, have been made
that are almost perfect in their construc-
ton, and the recent organization of the
International Air Power company, with
It's capital of millions of dollars, will do
much to remedy the slight defects that
now remain in the invention
The difficulties that caused the fail
ure OF all previous inventions have been
overcome in the new motors by the dis
covery of better methods of compression.
Now the work is done in successive
stages, with Intermediate cooling, as we'll
as by relocating the air just prior to the
time when it is introduced into the cylin-
ders of the motor. The relocating is done
by passing the compressed air through
a tank of hot water before placing it in
the cylinders.
The single and compound expansion
motors are very familiar in the con-
struction. In both systems the air is
carried in storage TASKS, but in the single
expansion motors the cylinders are in
direct connection with the aXles, while
the compound expansion motors are con-
nected to Il countershaft whose pinions
engage a gear wheel on the axle.
The success of both motors, how
ever, has been sufficient to warrant their
use on street cars and it will probably
not be long before companies in other
cities will take advantage of the new in
v%ention. In New York it is said to be the
intention of the Metropolitan
~ nov I System III SDlll
such sytem of operation in which case
the compound expansion motors would
be used on the trunk lines running north
and south and the single expansion mo-
tors on the cross-toWn and shorter lines.
The accompanying design is from
plans given out by President HOadlcy
Of the Air Power company and it fur
nisheS an excellent method of studying
the subject of how compressed air
makes the wheels of the car go round.
The diagram in the upper left hand cor
ner of the illustration explains the
flow of the compressed air. The air
is enclosed in the steel TASKS, r. r., at
a pressure Of 1900 pounds to the
square inch. From these TASKS, it
flows in pipes around the heater, H., to
the reducing valve, Y, where its pressure
is reduced and its flow equalized. The
air then passes through a hot coil to the
hlS ana low pressure motors, M M, in
which it drives the piston rods connected
with the gear attached to the car. From
the motor the air is allowed to ESCAPE
into the atmosphere. The diagram in the