An on demand supplemental oxygen delivery system that is self-calibrating includes
a tank containing a supply of oxygen and a nasal cannula through which the oxygen
may be provided to a patient when the system solenoid valve is in the open condition.
When the valve is in the closed condition, the cannula communicates with a pressure
transducer via a transducer line. An orifice is formed in the line so that the
pressure within the transducer line goes to atmospheric pressure when the valve
is in the open condition. The pressure transducer reads the atmospheric pressure
and directs it to a system controller where it is stored as a reference pressure.
