Molecular Sieve Generation of Aviator's Oxygen Breathing Gas Composition as a Function of Flow, Inlet Pressure, and Cabin Altitude

The molecular sieve method of generating an enriched-oxygen breathing gas is one of three candidate on-board oxygen generation (OBOG) systems under joint Navy-Air Force development for application in tactical aircraft. As part of this program, the performance of a nominal 2-man-capacity molecular sieve oxygen generation system (MSOG) was characterized under simulated flight conditions. Data were given on the composition (oxygen, nitrogen, carbon dioxide, and argon) of the MSOG-generated breathing gas as a function of inlet air pressure, altitude, and gas flow rate. The maximum oxygen concentration observed was 95% with the balance argon. Under certain conditions of pressure, altitude, and flow, the argon enrichment factor exceeded that of oxygen giving a maximum argon concentration of 6.4% with the balance oxygen. The performance of the MSOG was discussed in the context of aircraft operating envelopes using both diluter-demand and 100% delivery subsystems.