Oxygen breathing device with elongated supply time
Detailed is an aircraft oxygen emergency device including a chemical oxygen generator, an oxygen supply line including a first line section connecting the chemical oxygen generator with a flow regulator unit, and a second line section connecting the flow regulator unit with at least one oxygen mask for supplying oxygen to a mouth or a nose (or both) of a person at a breathing pressure.
1. Aircraft emergency oxygen system comprising:
a. a chemical oxygen generator configured to produce a stream of oxygen at a first pressure;
b. a flow control unit in fluid communication with and downstream of the chemical oxygen generator;
c. a manifold in fluid communication with and downstream of the flow control unit;
d. a throttle unit (i) in fluid communication with and downstream of the manifold and (ii) having a cross-section configured to increase pressure of the stream of oxygen at least in the flow control unit and the manifold to above the first pressure;
e. an oxygen mask in fluid communication with and downstream of the throttle unit;
f. a bypass flow line (i) extending between the chemical oxygen generator and the oxygen mask, (ii) commencing upstream of the manifold, (iii) terminating downstream of both the manifold and the throttle unit, and (iv) not passing through the manifold or the throttle unit; and
g. a safety valve (i) arranged in the bypass flow line and (ii) configured to allow fluid flow therethrough as a function of a pressure difference between the oxygen generator and the oxygen mask.
2. Aircraft emergency oxygen system according to claim 1 in which the chemical oxygen generator includes an internal volume having a size adapted to receive excess oxygen generated by the chemical oxygen generator.
3. Aircraft emergency oxygen system according to claim 2 in which the chemical oxygen generator is adapted to produce oxygen for supplying the oxygen mask at a minimum cabin temperature and a maximum flight altitude in case of a decompression event of a cabin of an aircraft in which it is located.
4. Aircraft emergency oxygen system according to claim 3 in which the internal volume has a corresponding to an excess oxygen volume at a predetermined pressure produced by the chemical oxygen generator (a) at a regular cabin temperature above the minimum cabin temperature, (b) at a low emergency flight altitude of the aircraft, or (c) both at the regular cabin temperature above the minimum cabin temperature and at the low emergency flight altitude.
5. Aircraft emergency oxygen system according to claim 1 in which (a) the fluid communication between the flow control unit and the chemical oxygen generator, the manifold and the flow control unit, and the throttle unit and the manifold defines a main flow line, (b) the main flow line is configured to store excess oxygen generated by the chemical oxygen generator, and (c) no pressure tank is present in either the main flow line or the bypass flow line.
6. Aircraft emergency oxygen system according to claim 1 in which the throttle unit comprises a non-actuated nozzle.
7. Aircraft emergency oxygen system according to claim 1 in which the throttle unit comprises a plurality of nozzles in a serial arrangement.
8. Aircraft emergency oxygen system according to claim 1 in which the throttle unit comprises a plurality of nozzles in a parallel arrangement.
9. Aircraft emergency oxygen system according to claim 1 in which the flow control unit comprises a timing unit.
10. Aircraft emergency oxygen system according to claim 9 in which the flow control unit further comprises (a) a bypass valve coupled to the timing unit and (b) a piston activated by the timing unit.
11. Aircraft emergency oxygen system according to claim 9 in which the timing unit comprises a mechanical or electrical timer.
12. Aircraft emergency oxygen system according to claim 10 in which the piston is selected from the group consisting of spring-loaded pistons, pneumatic pistons, and hydraulic pistons.
13. Aircraft emergency oxygen system according to claim 10 in which the timing unit is configured such that the bypass valve remains open for a predetermined time after activation of the chemical oxygen generator.
14. Aircraft emergency oxygen system according to claim 13 in which the predetermined time is approximately 3.5 minutes.
15. Aircraft emergency oxygen system according to claim 1 further comprising a plurality of oxygen masks.
16. Aircraft emergency oxygen system according to claim 15 further comprising a plurality of throttle units.
17. Aircraft emergency oxygen system according to claim 16 in which each of the plurality of oxygen masks is in fluid communication with and downstream of one of the plurality of throttle units.