Patent ID: 6871645

Claim:
A reduced-oxygen breathing apparatus comprising: (h) a vessel for gas mixing, wherein said gas mixing vessel is a hollow loop; (i) an ambient air inlet, said inlet being in fluid communication with said gas mixing vessel; (j) an outlet, said outlet being in fluid communication with said gas mixing vessel on one end and providing a controlled gas mixture to a subject at the opposite end; (k) an oxygen concentration sensor, said sensor being in fluid communication with the gas mixing vessel; (l) a nitrogen gas supply, said nitrogen gas supply being in fluid communication with said gas mixing vessel; (m) a nitrogen valve in fluid communication with said gas mixing vessel and said nitrogen gas supply, wherein said nitrogen valve controls flow of said nitrogen gas supply to said gas mixing vessel; and (n) a controller for said gas mixing, wherein: said oxygen concentration sensor sends a signal to said controller; said controller manipulates said signal; said controller provides an output signal to said nitrogen valve that adjusts said nitrogen gas supply to said gas mixing vessel in accordance with parameters set by an operator; and further comprising a nitrogen concentration sensor in fluid communication with said loop.