Oxygen Regulators

electrical coaxial cable. The quantity gauge is marked in liters from zero to the systems maximum storage capacity (i.e., 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 quantity of liquid in the converter falls below 1 liter. The maintenance of the quantity indicating and warning light system is the responsibility of the AE rating. You, as an AME, must understand the operation of the electrical portion of the LOX system in order to troubleshoot the indicator and warning systems. Oxygen Shutoff Valve The oxygen shutoff valve is installed in the system to control the flow of oxygen to the pilot or flight crew, as required. Figure 4-11 illustrates a typical manually operated two-position valve. This valve has an inlet port, outlet port, and a relief port. The pressure-relief valve is located in the inlet chamber to protect the oxygen regulator and crew member from excessive system pressure if there is a malfunction of the liquid oxygen converter. Also, excessive pressure due to thermal expansion of gaseous oxygen trapped within the system when not in use is relieved by this valve. If the oxygen system incorporates a console- mounted regulator, the shutoff valve is a part of the regulator. Composite Quick-Disconnect Coupling The purpose of the composite quick-dis- connect coupling is to provide a single-point connection for quickly connecting and dis- connecting the pilot with aircraft oxygen, anti-g, communications, and ventilation air services. Oxygen Lines LOX systems are classed as low-pressure systems. As such, low-pressure tubing is used in the manufacture and repair of LOX lines. All low- pressure tubing used in LOX systems are aluminum alloy 5052 tubing and is nonheat- treatable. It is manufactured in seamless, round lengths, and is annealed to provide greater flexibility. Aircraft oxygen systems are fitted with 5/16-, 3/8-, and 1/2-inch sizes. Low-pressure tubing is also installed from the pressure reducer to the outlets in reduced high-pressure oxygen systems. Oxygen Regulators Regulators used with LOX systems are either console-mounted or miniature mask-mounted. Figure 4-11.—Oxygen shutoff valve. The miniature mask-mounted regulator was especially designed for use with aircraft that have ejection seats. The console-mounted regulator is normally used in large nonelection seat equipped multiplace aircraft such as the E-2 and the P-3. Miniature Oxygen Breathing Regulator The miniature mask oxygen regulator, shown in a cutaway view in figure 4-12, is intended primarily for use in aircraft having a low-pressure LOX system and ejection seats. It is often referred to as a miniature mask-mounted regulator. Since it weighs only 2.3 ounces and measures approximately 2 5/8 inches in length and width, it is easily mounted on the oxygen mask or user’s torso harness. It is designed so that 4-16