4. Place the emergency control lever in the
EMERGENCY position. Pressure indicated on
PRESSURE/SUCTION manometer should read
2.0 to 4.0 inches of H2O.
5. Adjust the OUTPUT valve to draw 80
lpm through the regulator.
6. Place the diluter control lever in the
100-percent OXYGEN position. Pressure at outlet
of regulator, as indicated on PRESSURE/
SUCTION manometer, should be no less than 1.0
inches of H2O.
7. Close the OUTPUT valve. With zero
flow, outlet pressure should not exceed 5.5 inches
of H2O .
8. Adjust the output to 10 lpm. Hold the
emergency pressure control lever in TEST MASK
position. The output flow indicated on the
PRESSURE/SUCTION manometer should be
6.0 to 16.0 inches of H2O.
9. Close the OUTPUT valve. With zero flow,
outlet pressure should not exceed 17.5 inches of
H2O. Release the emergency pressure control
lever. If the regulator fails, adjust the emergency
pressure control lever stem to obtain 3.0 to 4.0
inches of H2O at 10 lpm first, then compensate
for excessive pressure drop at 80 lpm flow with
the elastic stop nut.
10. If the emergency pressure flows are not
within tolerance, locate the probable cause by
using the troubleshooting chart, table 12-15.
11. Close the N2 supply cylinder valve, by
using the LOW PRESSURE REGULATOR and
SYSTEM BLEED valve, relieve all pressure in the
test stand. Secure all test stand valves.
12. Test stand operator and CDI must sign
the Performance Test Sheet. The original, or a
copy of the Performance Test Sheet is forwarded
to the operational custodian of the regulator.
LIQUID OXYGEN CONVERTERS
The liquid oxygen converter assembly dis-
cussed in this chapter is a GCU-24/A, P/N
10C-0016-10 (fig. 12-5) manufactured by Essex
Cryogenics, Inc. (FSCM 19062). Information
concerning other types can be found in NAVAIR
13-1-6.4. The converter assembly is designed to
store and convert liquid oxygen (LOX) into
gaseous oxygen for the aircrewman during flight.
Table 12-16 contains the leading particulars for
the converter assembly.
Oxygen in its liquid state (approximately
–297 °F or –182 °C) is stored in a spherical
assembly consisting of inner and outer shells
separated by an annular space. The annular space
is evacuated to create a vacuum. This prevents the
transmittal of heat through the annular space. The
thermos bottle effect created retards heating and
eventual conversion of LOX to gaseous oxygen.
Valves, tubing, and fittings incorporated in the
converter assembly convert LOX to gas and direct
its flow at a controlled rate.
CONFIGURATION AND FUNCTION
The type GCU-24/A Liquid Oxygen Con-
verter Assembly (P/N 10C-0016-10) consists of
a sphere assembly, buildup and vent valve, relief
valve, pressure closing valve and associated
tubing and fittings. A capacitance-type probe
assembly, which sends an electrical signal to a
Table 12-15.—Troubleshooting (Emergency Pressure Test)
12-18
