Aircraft-Mounted Oxygen Regulators

Aircraft-Mounted Oxygen Regulators The MD series regulator is being used in several multiplace naval aircraft. There are two types of regulators in this series—the MD-1 (low- pressure) and MD-2 (high-pressure). The only difference found in these regulators is operating pressure. The operating pressure of the MD-1 regulator is 50 to 500 psi. The pressure gauge reads 0 to 500 psi. The operating pressure of the MD-2 regulator is 50 to 2,000 psi. The pressure gauge reads 0 to 2,000 psi. The following controls and indicators are located on the front panel of the regulator (fig. 4-13). The small oblong-shaped window area on the left side of the panel marked FLOW indicates the flow of oxygen through the regulator by a visible blinking action. The pressure gauge is found on the upper right of the panel and indicates inlet pressure to the regulator. The regulator has three control levers. A supply valve controller lever, located on the lower right corner, is used to control the supply of oxygen to the regulator; a diluter control lever, located on the lower center of the panel, has two positions— 100% OXYGEN and NORMAL OXYGEN; an emergency pressure control lever, located on the lower left of the panel, has three positions— EMERGENCY, NORMAL, and TEST MASK, and with the deluter lever in the 100% OXYGEN position, the regulator delivers 100 percent oxygen upon inhalation by the user. In the NORMAL OXYGEN position, the regulator delivers a mixture of air and oxygen with the air content decreasing until a cabin altitude of approximately 30,000 feet is reached. Above this altitude, 100-percent oxygen is delivered to the user upon inhalation. With the emergency pressure control lever in the EMERGENCY position, the regulator delivers positive oxygen pressure to the outlet at altitudes when positive pressure is not automatically delivered. In the TEST MASK position, oxygen is delivered to the mask under pressure too high to breathe and is used for checking the fit of the mask. The switch must be in the NORMAL position to assure normal system operation. Refer to figure 4-14 for the operation of an MD type regulator. 1. Supply oxygen entering through the oxygen inlet (1) is filtered and passes through the manifold Figure 4-13.—Regulator operating controls and indicators. 4-18