Man-rated fire suppression system and related methods

• US 8,408,322 B2
• Filed: 04/21/2006
• Issued: 04/02/2013
• Est. Priority Date: 12/02/2003
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Alliant Techsystems Incorporated (Northrop Grumman Corporation)
• Inventors: Blau, Reed J., Rozanski, James D., Truitt, Richard M., Lund, Gary K., Sampson, William P.
• Primary Examiner(s): Hwu, David
• Application Number:
  US11/409,257
• Publication Number:
  US 20060278409A1
• Time in Patent Office: 2,538 Days
• Field of Search: 169/9, 169/11, 169/12, 169/43, 169/46, 169/47, 169/84, 149/2, 149/19.1, 149/19.3, 222/3, 252 2- 8
• US Class Current: 169/30
• CPC Class Codes: A62C 13/22 with incendiary substances producing pressure gas
• CPC Class Codes: A62C 5/006 Extinguishants produced by combustion
• CPC Class Codes: A62C 99/0018 using gases or vapours that do not support combustion, e.g. steam, carbon dioxide
• CPC Class Codes: A62D 1/06 containing gas-producing, chemically-reactive components

Abstract

A fire suppression system for producing an inert gas mixture having a minimal amount of carbon monoxide, particulates, or smoke. The inert gas mixture may be generated by combusting a gas generant. The gas generant may be a composition that includes hexa(ammine)-cobalt(III)-nitrate. The fire suppression system also includes a heat management system to reduce a temperature of the inert gas mixture. In one embodiment, the system includes multiple gas generators and is configured to ignite the respective gas generant of each gas generator in a predetermined, time based sequential order. For example, the gas generant of each gas generator may be ignited in a sequential order at specified time intervals. Methods of extinguishing fires are also disclosed.

Claims

1. A fire suppression system comprising:

a plurality of gas generators, each gas generator of the plurality of gas generators having a solid gas generant composition positioned within a combustion chamber, separate from any other combustion chamber of any other gas generator of the plurality of gas generators, the combustion chamber having walls capable of withstanding a maximum working pressure, and each gas generator of the plurality of gas generators configured to generate a flow of gas into a defined space upon ignition of its respective solid gas generant composition; and

at least one initiating device configured to ignite each of the respective solid gas generant compositions of each gas generator of the plurality of gas generators, and to ignite the respective solid gas generant composition of at least one gas generator of the plurality of gas generators independent of ignition of the respective solid gas generant composition of at least one other gas generator of the plurality of gas generators in a predetermined, time-ordered sequence selected to achieve and substantially maintain pressure within a range of from about 0 psig to about 0.2 psig within the defined space during gas generation.

2. The fire suppression system of claim 1, wherein the plurality of gas generators is disposed within a common tower structure.

3. The fire suppression system of claim 1, wherein a first gas generator of the plurality of gas generators is disposed within a first tower structure, and wherein a second gas generator of the plurality of gas generators is disposed within a second tower structure.

4. The fire suppression system of claim 1, wherein, during operation, the solid gas generant composition of a first gas generator of the plurality of gas generators is ignited at a first time and the solid gas generant composition of a second gas generator of the plurality of gas generators is ignited at a second time approximately 1.5 seconds to approximately 2.5 seconds subsequent the first time.

5. The fire suppression system of claim 4, wherein, during operation, the solid gas generant compositions of any remaining gas generators of the plurality of gas generators are ignited at sequential intervals of approximately 1.5 seconds to approximately 2.5 seconds subsequent the second time.

6. The fire suppression system of claim 1, wherein the solid gas generant composition comprises hexa(ammine)cobalt(III)-nitrate (HACN) with less than approximately 0.1% charcoal.

7. The fire suppression system of claim 6, wherein the HACN is unrecrystallized.

8. The fire suppression system of claim 6, wherein the solid gas generant composition further comprises cuprous oxide (Cu₂O) and a polyacrylamide binder.

9. The fire suppression system of claim 8, wherein the solid gas generant composition further comprises a plurality of chopped fibers.

10. The fire suppression system of claim 1, wherein the solid gas generant composition is formed as at least one pellet having a first end surface and a second, opposing end surface, and wherein at least one surface feature is defined in the first end surface and configured to define an air gap between the first end surface and a structure disposed adjacent the first end surface.

11. The fire suppression system of claim 1, wherein the solid gas generant composition is substantially the same for each of the plurality of gas generators.

12. The fire suppression system of claim 1, wherein the plurality of gas generators are positioned within the defined space.

13. The fire suppression system of claim 12, wherein the plurality of gas generators are distributed in a spatial pattern within the defined space.

14. The fire suppression system of claim 1, wherein the predetermined, time-ordered sequence is selected to achieve and substantially maintain the pressure within a range of from about 0 psig to about 0.1 psig within the defined space during gas generation.

15. The fire suppression system of claim 1, wherein the predetermined, time-ordered sequence is selected to achieve and substantially maintain the pressure within a range of from about 0 psig to about 0.06 psig within the defined space during gas generation.

16. The fire suppression system of claim 1, wherein the plurality of gas generators have a quantity of solid gas generant composition selected to reduce the percentage of O₂ within the defined space to a predetermined range upon completion of gas generation.

17. The fire suppression system of claim 16, wherein the plurality of gas generators have a quantity of solid gas generant composition selected to reduce the percentage of O₂ within the defined space to a range of from about 10% to about 20% O₂ upon completion of gas generation.

18. The fire suppression system of claim 17, wherein the plurality of gas generators have a quantity of solid gas generant composition selected to reduce the percentage of O₂ within the defined space to a range of from about 13% to about 17% O₂ upon completion of gas generation.

19. A method of suppressing a fire in a defined space, the method comprising:

igniting a solid gas generant composition of each of a plurality of gas generators, each gas generator of the plurality of gas generators comprising a separate pressure controlling orifice, to generate a flow of gas through the separate pressure controlling orifice of each gas generator of the plurality of gas generators and into a defined space from each of the plurality of gas generators independent of generation of gas by any other of the plurality of gas generators, and igniting the respective solid gas generant composition of at least one gas generator of the plurality of gas generators and the respective solid gas generant composition of at least one other gas generator of the plurality of gas generators in a predetermined time-based sequence to achieve and substantially maintain pressure within a range of from about 0 psig to about 0.2 psig within the defined space during gas generation and to suppress a fire within the defined space.

20. The method according to claim 19, wherein igniting the respective solid gas generant composition of at least one gas generator of the plurality of gas generators and the respective solid gas generant composition of at least one other gas generator of the plurality of gas generators in a predetermined time-based sequence further includes igniting the solid gas generant composition of a first gas generator at a first time and sequentially igniting the solid gas generant compositions of remaining gas generators of the plurality of gas generators at approximately 1.5 to approximately 2.5 second intervals subsequent the first time.

21. The method according to claim 19, further comprising providing the solid gas generant as a composition including hexa(ammine)cobalt(III)-nitrate (HACN).

22. The method according to claim 19, further comprising providing the solid gas generant composition as a composition including less than approximately 0.1% charcoal.

23. The method according to claim 22, further comprising providing the HACN as unrecrystallized HACN.

24. The method according to claim 23, further comprising providing the solid gas generant composition as a composition including cuprous oxide (Cu₂O) and a polyacrylamide binder.

25. The method according to claim 24, further comprising providing the solid gas generant composition as a composition including a plurality of chopped fibers.

26. The method according to claim 25, further comprising forming the solid gas generant composition of each gas generator as a plurality of stacked pellets.

27. The method according to claim 26, further comprising defining an air gap between adjacent pellets of the plurality of stacked pellets.

28. The method according to claim 27, wherein defining an air gap includes forming at least one surface feature in an end surface of each of the plurality of pellets.

29. The method of claim 19, further comprising arranging the plurality of gas generators within the defined space.

30. The method of claim 19, further comprising providing substantially the same solid gas generant composition and substantially the same quantity of solid gas generant to each of the plurality of gas generators.

31. The method of claim 19, further comprising distributing the plurality of gas generators in a spatial pattern within the defined space.

33. The method of claim 19, further comprising selecting the predetermined time-based sequence to achieve and substantially maintain the pressure within a range of from about 0 psig to about 0.06 psig within the defined space during gas generation.

34. The method of claim 19, further comprising reducing the percentage of O₂ within the defined space at a predetermined rate and maintaining the reduced percentage of O₂ within the defined space to a predetermined range at least until the fire is suppressed.

35. The method of claim 34, wherein maintaining the reduced percentage of O₂ within the defined space to a predetermined range at least until the fire is suppressed comprises maintaining the reduced percentage of O₂ within the defined space at a range of from about 10% to about 20% at least until the fire is suppressed.

36. The method of claim 34, wherein maintaining the reduced percentage of O₂ within the defined space to a predetermined range at least until the fire is suppressed comprises maintaining the reduced percentage of O₂ within the defined space at a range of from about 13% to about 17% at least until the fire is suppressed.

32. The method of 19, further comprising selecting the predetermined time-based sequence to achieve and substantially maintain the pressure within a range of from about 0 psig to about 0.1 psig within the defined space during gas generation.

37. A fire suppression system comprising:

a plurality of gas generators, each gas generator of the plurality of gas generators having a solid gas generant composition positioned within a combustion chamber separate from any other combustion chamber of any other gas generator of the plurality of gas generators, the combustion chamber having walls capable of withstanding a maximum working pressure, each combustion chamber having a separate pressure controlling orifice from any other combustion chamber of any other gas generator, and each gas generator of the plurality of gas generators configured to generate a flow of gas into a defined space upon ignition of its respective solid gas generant composition; and

at least one initiating device configured to ignite each of the respective solid gas generant compositions of each gas generator of the plurality of gas generators, and to ignite the respective solid gas generant composition of at least one gas generator of the plurality of gas generators independent of ignition of the respective solid gas generant composition of at least one other gas generator of the plurality of gas generators in a predetermined, time-ordered sequence selected to achieve and substantially maintain pressure within a range of from about 0 psig to about 0.2 psig within the defined space during gas generation.