quick-disconnect quantity indicator lead disconnects
The vent and supply quick-disconnect couplings
are of two-piece construction. The male half is mounted
on the LOX converter, and the female half is attached to
the flexible oxygen supply and vent lines.
The coupling for the supply line contains a
spring-loaded check valve, which closes automatically
when the supply line is uncoupled from the converter.
This prevents contaminating the aircraft oxygen system
when the converter is removed for servicing. The vent
coupling has no check valve; however, it forms a
positive seal between the vent port of the converter and
overboard vent line.
The lungs would be damaged if gaseous oxygen
were breathed at the temperature at which it exits the
LOX converter. The purpose of the air-to-oxygen heat
Figure 7-11.--Aircraft air-to-oxygen heat exchanger.
exchanger is to increase the temperature of the gaseous
oxygen after it leaves the LOX converter. The heat
exchanger is located in the cockpit area of the aircraft to
expose it to a temperature capable of warming the
gaseous oxygen regardless of the altitude of the aircraft.
The low-pressure switch is located in the oxygen
The heat exchanger is aluminum with a large interior
supply line. It indicates to the flight crew, through a
surface area (fig. 7-11).
caution light in the aircraft cabin, when system pressure
falls below minimum operating pressure of the system.
This alerts and allows the pilot to descend to a safe
Quantity Indicating System
The quantity indicating system consists of a
quantity gauge and a warning light in the cockpit. A
quantity probe is also a part of the liquid oxygen
This probe senses the amount (quantity) of liquid in
the converter. This information is transmitted to the
quantity gauge by an electrical coaxial cable. The
quantity gauge is marked in liters from zero to the
system's maximum storage capacity (0 to 10). The
gauge constantly shows the remaining liquid in the
converter. The low-quantity warning light is also
connected to the coaxial cable and illuminates when the
Figure 7-10.--LOX converter installation.
quantity of liquid in the converter falls below 1 liter.