US Patent 7445663 Energy efficient oxygen concentrator

An energy efficient oxygen concentrator in which a compressor applies pressurized air to at least two gas separating elements which will pass a flow of oxygen while blocking a flow of nitrogen. The gas separating elements are alternately cycled between a gas separating mode for producing oxygen enriched gas and a purge mode for purging nitrogen from the elements. According to the invention, the speed of the cycle time is increased as the oxygen enriched gas flow requirement is decreased below the maximum concentrator output. The higher cycle speed reduces the maximum compressor pressure to reduce energy consumption.