Smart Molecular Sieve Oxygen Concentrator with Continuous Cycle Time Adjustment

摘要

A 'smart' molecular sieve oxygen concentrator (MSOC) is controlled by a set ofcomputer algorithms. The 'smart' system automatically adjusts concentrator operating parameters to accurately control product oxygen concentration while minimizing bleed air consumption. The purpose of this effort was to determine if concentrator performance could be controlled by computer algorithms which continuously adjust concentrator cycle time. A two-bed laboratory molecular sieve oxygen concentrator was constructed and instrumented. The concentrator was operated at ground level and ambient temperature. Computer algorithms or decision process were developed which allowed the software to control concentrator cycle time. Step changes in product flow from 5 to 40 standard liters/minute were induced by a flow controller. A signal representing the product oxygen concentration was produced by a medical gas analyzer and inputted into the computer algorithms. Using continuous cycle time adjustment over a range of 14 to 36 seconds, the 'smart' concentrator maintained the produce oxygen concentration within +2.5% of a desired concentration. The smallest incremental change in cycle time was 0.5 second. The highest observed overshoot in oxygen concentration which occurred during the step changes in product flow was about 12%. Inlet air consumption was reduced by approximately 40% when compared to operation at a constant cycle time. 'Smart' MSOC techniques, such as continuous cycle time adjustment, can significantly improve our ability to control oxygen concentrator performance. An added benefit will be reduced bleed air consumption which results in increased aircraft thrust and fuel economy.