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COMPRESSED AIR PLANT OF THE
ST. LOUIS TERMINAL STATION.
The compressed air power plant at the Union
terminal station at St. Louis is of note not only
from the care with which every detail of installation
has been worked out, but also because of the
diversity and extent of the applications of the
air power. It is a first-class example of the
central compressed air power plant—the fruit of
the present tendency towards centralization of
power.
The compressing plant proper is in the main
power house of the terminal and consists of two
duplex, steam-driven, two-stage air compressors,
built by the Ingersoll-Sergeant Drill co., of New
York. The type is that known by the makers as
Class "GC". The power of each compressor is
about 350 H. P., and at the rated speed of 100
R. P. M., the free air capacity of each unit is
2,180 cubic feet per minute. The steam pressure
applied is 150 lbs. and air is delivered to the
center of distribution at a pressure of 85 lbs. The
steam cylinders of the compressors are 18 inches
in diameter; air cylinders 32Vi and 20Vi inches in
diameter; the stroke is 24 inches. The machines
run non-condensing and a distinctive feature is
the piston inlet valve which is applied on both
high and low pressure air cylinders.
Cool air is led to the compressors from outside
the engine room through a supply conduit and the
air discharged is delivered to twin receivers in
a cooling house, or tower, outside the main build­
THE COAL TRADE BULLETIN. 37
ing. The air from these primary receivers passes
through a system of secondary receivers, headers
and cooling tubes, which reduces the temperature
to that of the outside air and condenses all moisture,
which collects in the receivers and is removed
through drain cocks. The perfection of the cooling
and drying process will be appreciated when
it is stated that only once or twice in the most
extreme weather has it been necessary to inject
alcohol into the air pipes to prevent freezing of
the delicate valve mechanisms of the switch and
signal system.
The applications of the air power are those
common to all railway, shop and yard service.
From the cooling house, which is the center of
distribution, five main-pipe lines radiate. The
distances to which power is transmitted range
from 1,800 to 5,000 feet, five distinct yards being
served from this central plant.
Among the applications of the air may be mentioned
the following: pneumatic tools, hoists and
jacks in the various shops and yards; charging
the brake reservoirs of stationary trains; cleaning
cars and car fittings; pneumatic dispatch tube
systems; the operation of air engines for a variety
of purposes, among them direct connected
generating sets supplying current for the electric
signal system; "Shone" ejectors, or displacement
pumps, handling the seepage water in the terminal
subway; direct-acting bilge pumps in the
accumulator pit of the hydraulic elevator system;
and, most important of all, a pneumatic switch