19-25D-26. The maintenance section is organized to
tank to the transfer tank is by gravity. It first passes
provide information and instructions for the three
through the transfer fill line shutoff valve (10) to the
levels of maintenance responsibility: organizational,
transfer tank. During this process, the gaseous oxygen
intermediate, and depot. The capability of the using or
produced by cooldown of the tank is vented back to the
supporting activity will be the limiting factor as to the
storage tank through the vent line shutoff valve (11).
level of maintenance that can be performed on the
Conditions of the transfer tank are monitored and
equipment. If maintenance of the equipment is beyond
indicated by pressure gauge (12) and liquid level gauge
the assigned maintenance responsibility of the using or
(13).
supporting activity, the next higher level will perform
When the transfer tank is filled to the desired level,
the maintenance.
as indicated by the liquid level gauge, valves (10) and
AMEs are only responsible for the organizational
(11) are closed. The converter lines are connected to the
maintenance of LOX trailers, which includes those
vent line connector (16) and filler valve (17). The filler
functions normally performed in support of daily
valve is opened to allow the pressure in the converter
operations. Normal operational maintenance func-
and transfer tank to equalize. The transfer tank PBU
tions include inspection and preventive maintenance.
coil is used to increase the pressure in the transfer tank
Table 8-1 will assist you in understanding these
to approximately 90 psig. This pressure is regulated by
functions.
the pressure buildup valve (21) as required to maintain
as high a pressure as possible during the servicing
System Servicing
operation.
Aircraft systems and LOX converters should be
serviced in accordance with the appropriate mainte-
WARNING
nance instructions manual (MIM).
The rate of pressure buildup depends on the
Only LOX conforming to MIL-0-27210, type II,
liquid level in the transfer tank. In a full tank, the
may be used in aircraft LOX systems. The firefighting
pressure will build extremely fast because of the
agents below are prohibited from use in conjunction
small amount of vapor space to be filled. Use extreme
with LOX-enriched fires.
caution in building the pressure, and never allow the
Soda-acid extinguishers
pressure to exceed 90 psig. Open transfer tank vent
Mechanical (liquid) foam
valve (11) to relieve the excessive pressure into the
storage tank. This will avoid the opening of the relief
Methyl bromide
valve (14) and the resultant undesirable discharge of
gaseous oxygen from the vent line.
Carbon tetrachloride
LOX is now able to flow from the transfer tank into
Q8-1. Open flames, smoking, or sparks should be
the converter. When the converter full indicator gauge
kept what minimum distance away from a
(19) indicates full, the overflow is returned to the
LOX handling area?
storage tank by passing through the converter vent line
Q8-2. True or False. Oxygen will burn when ignited.
shutoff valve (20). The filler valve (17) is then removed,
the transfer tank pressure buildup valve (21) is closed,
Q8-3. Identify the three major components of the
vent valve (20) is closed, and then vent line connector
TMU-70/M.
(16) is disconnected.
Q8-4. Explain the primary function of the transfer
The preceding process is repeated either until the
tank.
storage tank is empty or the maximum operating
Q8-5. What is the function of the transfer tank pres-
pressure, as indicated on the storage tank pressure
sure buildup valve?
gauge (7), has been replaced.
Q8-6. Using the fill-drain shutoff valve to control
Maintenance
LOX flow may cause what type of hazard?
Q8-7. Exterior cleanliness of the TMU-70/M LOX
Information and instructions for maintenance of
cart should be performed at what interval?
the TMU-70/M storage tank are found in NAVAIR
8-8
