liquid oxygen system components. Identify
is about 1.14 times as heavy as the same volume of
procedures for inspecting, checking, cleaning,
water. LOX, when warmed to ambient temperatures
testing, and adjusting liquid oxygen system
(about 70F), expands to about 862 times its liquid
components. Identify procedures for
volume. If you confine a cubic foot of LOX in 1 cubic
troubleshooting liquid oxygen systems.
foot of space, and allow it to warm past its critical
Identify procedures for repairing, removing,
temperature, it will exert an explosive pressure of
and replacing liquid oxygen system
about 12,000 pounds per square inch. That is roughly 6
components.
tons of pressure on each square inch of surface area.
For this reason, LOX storage containers are fitted with
At atmospheric pressure, gaseous oxygen
pressure-relief devices.
becomes liquid when it is cooled below its boiling
For Navy use, LOX is stored and handled at
point of -297F (-183C). By increasing the pressure
atmospheric pressure in well-insulated containers that
under which it is stored, oxygen can be liquefied at
maintain the liquid at its boiling point. Such containers
higher temperatures. Above the critical temperature of
are vented to the atmosphere to prevent the constantly
-182F (-119C), oxygen will not condense to a liquid
evaporating LOX from building up to a dangerously
regardless of how much pressure is applied. The
high pressure.
application of high pressure and low temperature to
convert gases into their liquid states is the science and
LIQUID OXYGEN STORAGE
technology of cryogenics. LOX is a cryogenic fluid.
Figure 10-1 is a chart that compares important
On naval air stations, liquid oxygen is centrally
temperatures of LOX to those of other liquids.
stored in large storage tanks, generally 2,000 gallons or
less. These tanks are designed to store the LOX at
LOX is a pale blue, nonviscous fluid that flows like
atmospheric pressure, with low evaporation losses.
water. One gallon of LOX weighs 9.527 pounds, which
Users of LOX then draw their supplies from these
tanks. The design features and practices described in
this chapter apply to all capacities, but the main
100 o
212 o
WATER BOILS
emphasis here is on tanks of 2,000 gallons or less.
Figure 10-2 shows a typical 2,000-gallon-capacity
storage tank.
Storage Tanks
32 o
0o
WATER FREEZES
All LOX storage tanks are basically similar,
regardless of their size or configuration, regardless of
0o
whether they are skid-mounted, trailer-mounted, or
permanently installed. All tanks consist of inner and
-70 o
-57 o
CARBON DIOXIDE
outer containers separated by an insulated space that is
FREEZES
CRITICAL
-118 o
-182 o
TEMPERATURE
OXYGEN
-183 o
-297 o
OXYGEN BOILS
-318 o
-194 o
AIR BOILS
-320 o
-196 o
NITROGEN BOILS
-210 o
-346 o
FREEZES
-361o
-218 o
OXYGEN
FREEZES
ASf10002
FAHRENHEIT
CENTIGRADE
Figure 10-2.--2,000 gallon capacity liquid oxygen storage
ASf10001
Figure 10-1.--Comparative temperature chart.
tank.
10-2
