5. Connect the converter vent line (C-3) to the
build up in the transfer tank and transfer the
converter vent fitting.
remaining LOX back into the storage tank.
6. Connect the AF filler valve (C-2) to the
b. Monitor the transfer tank liquid level gauge
converter fill fitting:
(LG-2). When the gauge indicates that the
transfer tank is empty, close the transfer tank
a. Position the filler valve against the purge
fitting, and turn the housing clockwise,
pressure buildup valve (GV-5) and the
locking the filler valve in place.
transfer tank fill line shutoff valve (LV-2).
b. Push the knurled knob forward, and rotate it
12. Check that the only valve remaining open is the
clockwise, locking the filler valve in the
storage tank vent valve (GV-6).
7. Open the transfer tank pressure buildup valve
(GV-5) momentarily, and observe the transfer tank
Maintenance procedures for the TMU-70/M LOX
pressure gauge (P-2). When the transfer tank pressure
servicing trailer can be found in Servicing Trailer,
rises to approximately 90 psig, close the transfer tank
L i q u i d O x y ge n , L o w L o s s , C l o s e d L o o p , Ty p e
pressure buildup valve. It may be necessary to open and
TMU-70/M, NAVAIR 19-25D-26. The maintenance
close the transfer tank pressure buildup valve repeatedly
section in this manual is organized to address the three
to maintain the desired pressure (90 psig) during
levels of maintenance responsibility: organizational,
intermediate, and depot. The maintenance capability
of the activity using or supporting the equipment will
be the limiting factor as to the level of maintenance
that can be performed on the equipment. If
The rate of pressure buildup in the transfer tank
maintenance of the equipment is beyond the assigned
depends on the liquid level in the tank. On a full
maintenance responsibility of the activity, the next
tank, the pressure will build very fast because of
higher level of maintenance activity will perform the
the small amount of vapor space to be filled. Use
extreme caution in building the pressure in any
case, and NEVER allow the pressure to exceed
THE STORAGE TANK.--The storage tank of
the LOX cart requires only corrosion control and
cleaning at the O and I level. If you suspect the tank has
lost its vacuum, then look for signs of frost build-up on
the outside of the tank. If you suspect that the LOX loss
8. Open the converter vent line shutoff valve
(GV-4) to allow LOX vapor to return to the storage tank.
loss rate test.
NOTE: Monitor the converter full indicator gauge
TOGGLE VALVES.--The TMU-70/M has three
(F-1). While the converter is filling, the gauge should
toggle valves that are susceptible to leaking. (See fig.
indicate "GAS." When the converter is full, the gauge
10-8.) If a toggle valve is leaking externally, you can
should indicate "LIQUID."
detect the problem by conducting a bubble test
9. As soon as the converter full indicator gauge
(discussed later in this section). Fixing the problem
(F-1) indicates "LIQUID," disconnect the filler valve
may involve nothing more than tightening the valve
or replacing the valve packing.
10. Close the transfer tank pressure buildup valve
If a toggle valve is leaking internally, however, it
(GV-5) and the converter vent line shutoff valve (CV-4).
won't show the type of symptoms found with a
Then, disconnect the converter vent line connector
bubble test. Internal leaks show up as unexplained
increases or decreases in liquid quantities or gas
pressure. For example, you may note that the
11. If no other converters are to be serviced, empty
quantity gauge on the transfer tank continues to
the transfer tank.
rise, even though the transfer tank fill line shutoff
valve is closed. Internal leaking requires at least
a. Open the transfer tank fill line shutoff valve
replacement of the seats. In some cases, replacement
(LV-2) and the transfer tank pressure buildup
of the entire valve may be necessary.
valve (GV-5). This will cause pressure to