Patent ID: 8640702

Claim:
An emergency oxygen supply system for an aircraft with a pressurizable passenger cabin comprising: a source of supplemental breathable oxygen; a conduit connected to said source of supplemental breathable oxygen; an upstream first on-off inlet valve connected to said conduit downstream from said source of supplemental breathable oxygen; a downstream second on-off inlet valve connected to said conduit downstream serially from said first on-off inlet valve; a plurality of breathing devices connected to said conduit downstream from said downstream second on-off inlet valve; at least one cabin air pressure transducer for generating a cabin air pressure input signal representing the cabin pressure and a corresponding altitude; a second pressure transducer connected to said conduit between said upstream first on-off inlet valve and said downstream second on-off inlet valve, and a third pressure transducer connected to said conduit between said second on-off inlet valve and said plurality of breathing devices, said second and third pressure transducers being configured to sense a gas pressure in said conduit at locations downstream of the first and second on-off inlet valves, respectively; and a pressure controller connected to said at least one cabin air pressure transducer for receiving said cabin air pressure input signal, said pressure controller being connected to and controlling the operation of said first and second on-off inlet valves in response to said cabin air pressure input signal received from said at least one cabin air pressure transducer, and said pressure controller being operative to control the operation of said first and second on-off inlet valves in response to said second and third pressure transducers, respectively.