Method and system for extinguishing fire in an enclosed space

• US 20020070035A1
• Filed: 09/18/2001
• Published: 06/13/2002
• Est. Priority Date: 10/18/2000
• Status: Active Grant

• Current Assignee: Airbus Operations GmbH (Airbus SE)
• Original Assignee: Airbus Deutschland GmbH (Airbus SE)
• Inventors: Grabow, Thomas, Kallergis, Konstantin
• Granted Patent: US 6,601,653 B2
• Time in Patent Office: Days
• US Class Current: 169/16
• CPC Class Codes: A62C 3/08 in aircraft A62C3/0207 takes precedence
• CPC Class Codes: A62C 99/0018 using gases or vapours that do not support combustion, e.g. steam, carbon dioxide

Abstract

A system for suppressing fire in an enclosed space, e.g. an aircraft cabin or freight compartment, includes nitrogen tanks and/or generators to rapidly supply a limited quantity of nitrogen with a high flow rate, and a membrane system to supply an essentially unlimited quantity of nitrogen at a lower supply rate for a long duration. The membrane system includes a selectively permeable membrane that separates nitrogen gas from ambient environmental air that is supplied into the membrane system. Once a fire is detected, nitrogen is supplied from the nitrogen gas tanks and/or generators at a high rate to rapidly increase the nitrogen concentration and establish a reduced oxygen concentration (e.g. 12 vol. %) in the enclosed space. Then, nitrogen is supplied from the membrane system at a reduced rate for a long duration to maintain the reduced oxygen concentration in the enclosed space until the fire is extinguished by oxygen starvation.

Claims

1. A system for suppressing a fire in an enclosed space, comprising:

at least one nitrogen supply device selected from the group consisting of compressed nitrogen gas storage tanks and nitrogen gas generators, adapted to supply a first flow of nitrogen gas;

a nitrogen preparation unit adapted to supply a second flow of nitrogen gas, at a lower maximum flow rate and for a longer maximum duration than said first flow of nitrogen gas supplied by said at least one nitrogen supply device;

at least one nozzle that is arranged in the enclosed space and that is adapted to emit nitrogen gas from said nozzle into the enclosed space; and

a pipe arrangement connecting said at least one nitrogen supply device and said nitrogen preparation unit to said at least one nozzle.

2. The system according to claim 1, further comprising a flow rate limiting device interposed in said pipe arrangement between said at least one nozzle on the one hand and said at least one nitrogen supply device and said nitrogen preparation unit on the other hand.

3. The system according to claim 2, further comprising a pressure reservoir interposed in said pipe arrangement and connected to said flow rate limiting device upstream on a side thereof opposite said at least one nozzle.

4. The system according to claim 2, further comprising a controller connected for control signal transmission to said flow rate limiting device, a fire detector arranged in the enclosed space and connected by a detector signal transmission link to said controller, and a gas sensor arranged in the enclosed space and connected by a sensor signal transmission link to said controller.

5. The system according to claim 4, wherein said gas sensor comprises an oxygen gas concentration sensor.

6. The system according to claim 4, wherein said gas sensor comprises a nitrogen gas concentration sensor.

7. The system according to claim 1, wherein said at least one nitrogen supply device is adapted to supply said first flow of nitrogen gas through said pipe arrangement and said at least one nozzle into the enclosed space so as to reduce an ambient oxygen concentration to establish a reduced oxygen concentration in the enclosed space, and said nitrogen preparation unit is adapted to supply said second flow of nitrogen gas through said pipe arrangement and said at least one nozzle into the enclosed space so as to maintain said reduced oxygen concentration in the enclosed space.

8. The system according to claim 7, wherein said reduced oxygen concentration is a maximally effective fire suppressing concentration of oxygen.

9. The system according to claim 1, comprising a plurality of said nitrogen supply devices that can all be activated simultaneously to cumulatively together supply said first flow of nitrogen gas to initially build up an initial concentration of nitrogen gas in the enclosed space.

10. The system according to claim 1, excluding halon, carbon dioxide, and water as fire suppressing agents.

11. The system according to claim 1, including and using only nitrogen gas as a fire suppressing agent.

12. The system according to claim 1, wherein said nitrogen preparation unit comprises a membrane system that selectively separates nitrogen gas from air, and wherein said membrane system has an air inlet and has a nitrogen outlet connected to said pipe arrangement.

13. The system according to claim 12, further in combination with a vehicle equipped with an air conditioning system, wherein said air inlet of said membrane system is connected to said air conditioning system to receive air therefrom.

14. The system according to claim 12, further comprising an exhaust air outlet channel and a valve interconnected between said exhaust air outlet channel and said air inlet of said membrane system to provide air to said air inlet.

15. The system according to claim 12, wherein said membrane system includes at least one selectively permeable membrane that is selectively permeable by nitrogen, so as to allow nitrogen to pass through said membrane from a side thereof facing said air inlet to a side thereof facing said nitrogen outlet.

16. The system according to claim 1, further comprising a pressure compensating device connected to the enclosed space.

18. The method according to claim 17, wherein said first flow rate is at least five times said second flow rate.

19. The method according to claim 17, wherein said first flow rate is at least ten times said second flow rate.

20. The method according to claim 17, wherein said first flow rate is a maximum possible flow rate that can be achieved by a fire suppression system that is supplying said nitrogen gas.

21. The method according to claim 17, wherein said supplying of said second flow of nitrogen gas is carried out for a longer duration than said supplying of said first flow of nitrogen gas.

22. The method according to claim 17, wherein said supplying of said first flow of nitrogen gas is continued only until said reduced oxygen concentration is achieved in said enclosed space, and said supplying of said second flow of nitrogen gas is continued until said fire has been completely extinguished.

23. The method according to claim 17, wherein said reduced oxygen concentration is a maximally effective fire extinguishing concentration of oxygen.

24. The method according to claim 17, wherein said reduced oxygen concentration is in a range from 11 to 13 volume percent.

25. The method according to claim 17, wherein said reduced oxygen concentration is about 12 volume percent.

26. The method according to claim 17, wherein said step b) comprises supplying said first flow of nitrogen gas from at least one of a compressed nitrogen gas storage tank and a nitrogen gas generator carrying out a nitrogen-emitting chemical reaction, and said step c) comprises supplying said second flow of nitrogen gas from a nitrogen preparation unit that includes a selectively permeable membrane, by supplying air to a first side of said membrane, selectively permeating nitrogen gas from said air through said membrane from said first side to a second side thereof, and then supplying said nitrogen gas from said second side of said membrane to said enclosed space.

27. The method according to claim 17, excluding the use of halon, carbon dioxide, and water for extinguishing said fire.

28. The method according to claim 17, using only said nitrogen gas for extinguishing said fire.

17. A method of suppressing a fire in an enclosed space, comprising the steps:

a) detecting a fire in an enclosed space;

b) after said step a), supplying a first flow of nitrogen gas at a first flow rate into said enclosed space so as to reduce a prior oxygen concentration to a reduced oxygen concentration in said enclosed space; and

c) after said step b), supplying a second flow of nitrogen gas at a second flow rate into said enclosed space so as to maintain said reduced oxygen concentration in said enclosed space, wherein said first flow rate is greater than said second flow rate; and

d) extinguishing said fire because said reduced oxygen concentration is insufficient to sustain said fire.