Fire suppression system using high velocity low pressure emitters

• US 20060278410A1
• Filed: 06/13/2006
• Published: 12/14/2006
• Est. Priority Date: 06/13/2005
• Status: Active Grant

• Current Assignee: Victaulic Company
• Original Assignee: Victaulic Company
• Inventors: Ballard, Robert J., Ide, Stephen R., Reilly, William J., Blease, Kevin J.
• Granted Patent: US 7,726,408 B2
• Time in Patent Office: Days
• US Class Current: 169/37
• CPC Class Codes: A62C 31/005 using nozzles
• CPC Class Codes: A62C 31/02 Nozzles specially adapted for fire-extinguishing
• CPC Class Codes: A62C 35/60 wet, i.e. containing extinguishing material even when not in use
• CPC Class Codes: A62C 35/64 pressurised
• CPC Class Codes: A62C 99/0072 using sprayed or atomised water
• CPC Class Codes: B05B 1/265 the liquid or other fluent material being symmetrically deflected about the axis of the nozzle
• CPC Class Codes: B05B 7/08 with separate outlet orifices, e.g. to form parallel jets , i.e. the axis of the jets being parallel, to form intersecting jets , i.e. the axis of the jets converging but not necessarily intersecting at a point
• CPC Class Codes: B05B 7/0853 with one single gas jet and several jets constituted by a liquid or a mixture containing a liquid B05B7/0815 takes precedence
• CPC Class Codes: B05B 7/0892 the outlet orifices for jets constituted by a liquid or a mixture containing a liquid being disposed on a circle

Abstract

A fire suppression system is disclosed. The system includes a source of pressurized gas and a source of pressurized liquid. At least one emitter is in fluid communication with the liquid and gas sources. The emitter is used to establish a gas stream, atomize and entrain the liquid into the gas stream and discharge the resulting liquid-gas stream onto the fire. A method of operating the system is also disclosed. The method includes establishing a gas stream having first and second shock fronts using the emitter, atomizing and entraining the liquid with the gas at one of the two shock fronts to form a liquid-gas stream, and discharging the stream onto the fire. The method also includes creating a plurality of shock diamonds in the liquid-gas stream discharged from the emitter.

Claims

1. A fire suppression system, comprising:

a source of pressurized gas;

a source of pressurized liquid;

at least one emitter for atomizing and discharging said liquid entrained in said gas on a fire;

a gas conduit providing fluid communication between said pressurized gas source and said emitter;

a piping network providing fluid communication between said pressurized liquid source and said emitter;

a first valve in said gas conduit controlling pressure and flow rate of said gas to said emitter;

a second valve in said piping network controlling pressure and flow rate of said liquid to said emitter;

a pressure transducer measuring pressure within said gas conduit;

a fire detection device positioned proximate to said emitter; and

a control system in communication with said first and second valves, said pressure transducer and said fire detection device, said control system receiving signals from said pressure transducer and said fire detection device and opening said valves in response to a signal indicative of a fire from said fire detection device, said control system actuating said first valve so as to maintain a predetermined pressure within said gas conduit for operation of said emitter.

2. A system according to claim 1, further comprising:

a plurality of compressed gas tanks comprising said source of pressurized gas; and

a high pressure manifold providing fluid communication between said compressed gas tanks and said first valve.

3. A system according to claim 2, further comprising:

a plurality of control valves, each one being associated with one of said compressed gas tanks; and

a supervisory loop in communication with said control system and said control valves for monitoring the status of said control valves.

4. A system according to claim 1, wherein said emitter comprises:

a nozzle having an inlet connectable in fluid communication with said first valve and an outlet;

a duct connectable in fluid communication with said second valve, said duct having an exit orifice positioned adjacent to said outlet; and

a deflector surface positioned facing said outlet in spaced relation thereto, said deflector surface having a first surface portion oriented substantially perpendicularly to said nozzle and a second surface portion positioned adjacent to said first surface portion and oriented non-perpendicularly to said nozzle, said liquid being dischargeable from said orifice, and said gas being dischargeable from said nozzle outlet, said liquid being entrained with said gas and atomized forming a liquid-gas stream that impinges on said deflector surface and flows away therefrom onto said fire.

5. A system according to claim 4, wherein said nozzle is a convergent nozzle.

6. A system according to claim 4, wherein said outlet has a diameter between about ⅛

and about 1 inch.

7. A system according to claim 4, wherein said orifice has a diameter between about 1/32 and about ⅛

inch.

8. A system according to claim 4, wherein said deflector surface is spaced from said outlet by a distance between about 1/10 and about ¾

of an inch.

9. A system according to claim 4, wherein said first surface portion comprises a flat surface and said second surface portion comprises an angled surface surrounding said flat surface.

10. A system according to claim 9, wherein said flat surface has a diameter approximately equal to the diameter of said outlet.

11. A system according to claim 9, wherein said angled surface has a sweep back angle between about 15°

and about 45°

measured from said flat surface.

12. A system according to claim 4, wherein said first surface portion comprises a flat surface and said second surface portion comprises a curved surface surrounding said flat surface.

13. A system according to claim 4, wherein said deflector surface includes a closed end resonance cavity having an open end positioned in facing relation with said outlet.

14. A system according to claim 13, wherein said first surface portion surrounds said resonance cavity.

15. A system according to claim 14, wherein said second surface portion surrounds said first surface portion.

16. A system according to claim 4, wherein said exit orifice is spaced from said outlet by a distance between about 1/64 and ⅛

of an inch.

17. A system according to claim 4, wherein said nozzle is adapted to operate over a gas pressure range between about 29 psia and about 60 psia.

18. A system according to claim 4, wherein said duct is adapted to operate over a liquid pressure range between about 1 psig and about 50 psig.

19. A system according to claim 4 wherein said emitter comprises:

a nozzle having an inlet connectable in fluid communication with said pressurized gas source and an outlet;

a duct connectable in fluid communication with said pressurized liquid source, said duct having an exit orifice positioned adjacent to said outlet; and

a deflector surface positioned facing said outlet in spaced relation thereto, said deflector surface being positioned so that a first shock front is formed between said outlet and said deflector surface, and a second shock front is formed proximate to said deflector surface for a predetermined pressure of said gas supplied to said emitter and discharged from said nozzle outlet.

20. A system according to claim 19, wherein said duct is positioned and oriented such that said liquid discharged from said orifice is entrained with said gas proximate one of said shock fronts.

21. A system according to claim 20, wherein said deflector surface is positioned so that shock diamonds form in said liquid-gas stream.

22. A system according to claim 20, wherein said orifices are positioned relatively to said outlet so as to cause said liquid to be entrained with said gas proximate to said second shock front.

23. A system according to claim 20, wherein said ducts are angularly oriented toward said nozzle so as to cause said liquid to be entrained with said gas proximate to said first shock front.

24. A system according to claim 19, comprising sizing said nozzle so as to create an overexpanded gas flow jet from said nozzle for a predetermined gas pressure.

25. A system according to claim 19, further comprising sizing said nozzle so that said flow jet creates no significant noise other than gas jet noise.

26. A system according to claim 19, wherein said deflector surface comprises a flat surface portion oriented substantially perpendicularly to said outlet and an angled surface portion surrounding said flat surface portion, said angled surface portion determining an included angle of a flow pattern from said emitter.

27. A method of operating a fire suppression system, said system having an emitter comprising:

a nozzle having an inlet connected in fluid communication with a pressurized gas source and an outlet;

a duct connected in fluid communication with a pressurized liquid source, said duct having an exit orifice positioned adjacent to said outlet;

a deflector surface positioned facing said outlet in spaced relation thereto;

said method comprising;

discharging said liquid from said orifice;

discharging said gas from said outlet;

establishing a first shock front between said outlet and said deflector surface;

establishing a second shock front proximate to said deflector surface;

entraining said liquid in said gas to form a liquid-gas stream; and

projecting said liquid-gas stream from said emitter.

28. A method according to claim 27, wherein said system comprises:

a plurality of compressed gas tanks forming said source of pressurized gas;

a plurality of control valves, each one being associated with one of said compressed gas tanks;

a supervisory loop in communication with said control valves for monitoring the open and closed status of said control valves; and

said method comprising monitoring the status of said control valves and maintaining said control valves in an open configuration during operation of said system.

29. A method according to claim 27, comprising establishing a plurality of shock diamonds in said liquid-gas stream.

30. A method according to claim 27, comprising creating an overexpanded gas flow jet from said nozzle.

31. A method according to claim 27, comprising supplying gas to said inlet at a pressure between about 29 psia and about 60 psia.

32. A method according to claim 27, comprising supplying liquid to said duct at a pressure between about 1 psig and about 50 psig.

33. A method according to claim 27, further comprising entraining said liquid with said gas proximate to said second shock front.

34. A method according to claim 27, further comprising entraining said liquid with said gas proximate to said first shock front.

35. A method according to claim 27, wherein said fluid stream does not separate from said deflector surface.

36. A method according to claim 27, comprising creating no significant noise from said emitter other than gas jet noise.

37. A method according to claim 36, where said gas jet noise has frequency components no greater than about 6 kHz.

38. A method according to claim 27, further comprising generating momentum in said gas flow jet.

39. A method according to claim 38, wherein said liquid-gas stream has a velocity of about 1,200 ft/min at a distance of about 18 inches from said emitter.

40. A method according to claim 38, wherein said liquid-gas stream has a velocity of about 700 ft/min at a distance of about 8 feet from said emitter.

41. A method according to claim 27, further comprising establishing flow pattern from said emitter having a predetermined included angle by providing an angled portion of said deflector surface.

42. A method according to claim 27, comprising drawing liquid into said gas flow jet using a pressure differential between the pressure in said gas flow jet and the ambient.

43. A method according to claim 27, comprising entraining said liquid into said gas flow jet and atomizing said liquid into drops less than 20 μ

m in diameter.

44. A method according to claim 27, comprising drawing an oxygen depleted smoke layer into said gas flow jet and entraining said smoke layer with said fluid stream of said emitter.

45. A method according to claim 27, comprising discharging an inert gas from said outlet.

46. A method according to claim 27, comprising discharging a mixture of inert and chemically active gases from said outlet.

47. A method according to claim 46, wherein said gas mixture comprises air.

48. A method of operating a fire suppression system, said system having an emitter comprising:

a nozzle having an inlet connectable in fluid communication with a pressurized gas source and an outlet;

a duct connectable in fluid communication with a pressurized liquid source, said duct having an exit orifice positioned adjacent to said outlet;

a deflector surface positioned facing said outlet in spaced relation thereto;

said method comprising;

discharging said liquid from said orifice;

discharging said gas from said outlet creating an overexpanded gas flow jet from said nozzle;

entraining said liquid in said gas to form a liquid-gas stream; and

projecting said liquid-gas stream from said emitter.

49. A method according to claim 48, further comprising:

establishing a first shock front between said outlet and said deflector surface;

establishing a second shock front proximate to said deflector surface; and

entraining said liquid in said gas proximate to one of said first and second shock fronts.

50. A method according to claim 48, further comprising establishing a plurality of shock diamonds in said liquid-gas stream from said emitter.