An electronic-breathing mask system uses an electro-pneumatic valve for controlling air flow to a pilot. The system provides a continuous flow of air in an amount proportional to the pressure in the mask. The pressure in the mask is compared against a setpoint pressure to maintain a minimum derived pressure...http://www.google.es/patents/US4827964?utm_source=gb-gplus-sharePatente US4827964 - System for metering of breathing gas for accommodation of breathing demand
System for metering of breathing gas for accommodation of breathing demand
