Mist generating apparatus and method

• US 20090314500A1
• Filed: 03/13/2009
• Published: 12/24/2009
• Est. Priority Date: 09/15/2006
• Status: Active Grant

• Current Assignee: Tyco Fire Products LP (Johnson Controls International plc)
• Original Assignee: Tyco Fire & Security GmbH (Johnson Controls International plc)
• Inventors: Wallis, Alexander Guy, Fenton, Marcus Brian Mayhall
• Granted Patent: US 8,789,769 B2
• Time in Patent Office: Days
• US Class Current: 169/16
• CPC Class Codes: A62C 31/02 Nozzles specially adapted for fire-extinguishing
• CPC Class Codes: A62C 99/0072 using sprayed or atomised water
• CPC Class Codes: B05B 1/02 designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, or having an outlet of particular shapeB05B1/26, B05B1/28, B05B1/34 take precedence
• CPC Class Codes: B05B 7/0433 with one inner conduit of gas surrounded by an external conduit of liquid upstream the mixing chamber
• CPC Class Codes: B05B 7/0458 the gas and liquid flows being perpendicular just upstream the mixing chamber
• CPC Class Codes: B05B 7/0466 with means for deflecting the central liquid flow towards the peripheral gas flow

Abstract

Apparati for generating a mist are disclosed. One apparatus is disclosed, which has an elongate hollow body (12) and an elongate member (14) located within the body (12). A transport fluid passage (16) and a nozzle (32) are defined between the body (12) and the elongate member (14). The transport fluid passage (16) has a throat portion of reduced cross-sectional area and is in fluid communication with the nozzle (32). The elongate member (14) includes a working fluid passage (26) and one or more communicating openings, such as for example, bores, annuli, and combinations thereof, (30) extending radially outward from the working fluid passage (26). The openings (30) permit a working fluid (e.g. water) to be passed into the transport fluid passage (16), whereupon the working fluid is subjected to shear forces by a high velocity transport fluid (e.g. steam). The shearing of the working fluid results in the generation of a mist formed from droplets of substantially uniform size. Methods of generating a mist using such apparati are also disclosed. Also provided are mists for fire suppression produced using an apparatus disclosed herein, as well as fire suppression systems that include any of the apparati disclosed herein. Further provided are devices, methods, and mists for various other applications including turbine cooling and decontamination.

Claims

1. An apparatus for generating a mist, comprising:

a) an elongate hollow body; and

b) an elongate member located within the body such that a first transport fluid passage and a nozzle are defined between the body and the elongate member, the first transport fluid passage having a convergent-divergent internal geometry and being in fluid communication with the nozzle, wherein the elongate member includes a working fluid passage and one or more communicating openings extending radially outwardly from the working fluid passage, the openings allowing fluid communication between the working fluid passage and the first transport fluid passage.

2. The apparatus of claim 1, wherein the one or more communicating openings are independently selected from the group consisting of communicating bores, communicating annuli, and combinations thereof.

3. The apparatus of claim 2, wherein the one or more communicating openings are one or more communicating bores.

4. The apparatus of claim 2, wherein the one or more communicating openings are substantially perpendicular to the first transport fluid passage.

5. The apparatus of claim 2, wherein the one or more communicating openings have an inlet connected to the working fluid passage and an outlet connected to the first transport fluid passage, the outlet having a greater cross-sectional area than the inlet.

6. The apparatus of claim 1, wherein the body has an internal wall having an upstream convergent portion and a downstream divergent portion, the convergent and divergent portions at least in part forming the convergent-divergent internal geometry of the first working fluid passage.

7. The apparatus of claim 6, wherein a first end of the elongate member has a cone-shaped projection, wherein the nozzle is defined between the divergent portion of the internal wall and the cone-shaped projection.

8. The apparatus of claim 7, wherein the cone-shaped projection has a portion having an inclined surface rising from the surface of the cone.

9. The apparatus of claim 7, wherein the elongate member further includes a second transport fluid passage having an outlet adjacent the tip of the cone-shaped projection.

10. The apparatus of claim 9, wherein the second transport fluid passage includes an expansion chamber.

11. The apparatus of claim 2, wherein the communicating openings allowing communication between the working fluid passage and the first transport fluid passage are first openings, and the body includes a second working fluid passage and one or more second communicating openings allowing fluid communication between the second working fluid passage and the first transport fluid passage, wherein the second working fluid passage is located radially outward of the first working fluid passage and the first transport fluid passage.

12. The apparatus of claim 11, wherein the second communicating openings are substantially perpendicular to the first transport fluid passage.

13. The apparatus of claim 11, wherein the first and second communicating openings are co-axial.

14. The apparatus of claim 1, wherein the elongate member further includes:

a) a second transport fluid passage located radially outward of the working fluid passage;

b) one or more first communicating openings extending radially outward from the working fluid passage, the first communicating openings allowing fluid communication between the working fluid passage and the second transport fluid passage; and

c) one or more second communicating openings extending radially outward from the second transport fluid passage, the second communicating openings allowing fluid communication between the second transport fluid passage and the first transport fluid passage,

wherein the first and second communicating openings are substantially perpendicular to the second and first transport fluid passages, respectively.

15. The apparatus of claim 14, wherein the elongate member further includes a third transport fluid passage adapted to supply transport fluid into the second transport fluid passage adjacent the first and second communicating openings.

16. The apparatus of claim 15, wherein the second and/or third transport fluid passages adjacent the first communicating opening have a convergent-divergent geometry.

17. The apparatus of claim 14, wherein the first and second communicating openings are independently selected from the group consisting of communicating bores, communicating annuli, and combinations thereof.

18. The apparatus of claim 17, wherein the first and second communicating openings are one or more communicating bores.

19. The apparatus of claim 1, wherein the first transport fluid passage communicates with the nozzle via an outlet and a second transport fluid passage in fluid communication with the outlet, wherein the second transport fluid passage has a convergent-divergent internal geometry and is substantially perpendicular to the first transport fluid passage.

20. The apparatus of claim 1, further comprising a mixing chamber located between the first transport fluid passage and the nozzle, and a second transport fluid passage in communication with the mixing chamber and the first transport fluid passage, wherein the second transport fluid passage is adapted to supply transport fluid to the mixing chamber in a direction of flow substantially opposed to a direction of flow of transport fluid from the first transport fluid passage.

28. A mist for fire suppression, which mist is produced using an apparatus according to claim 1.

21. A method of generating a mist, the method comprising the steps of:

a) supplying a working fluid through a working fluid passage;

b) supplying a first transport fluid through a first transport fluid passage;

c) forcing the working fluid from the working fluid passage into the first transport fluid passage via one or more communicating openings extending radially outward from the working fluid passage;

d) accelerating the first transport fluid upstream of the communicating openings so as to provide a high velocity transport fluid flow; and

e) applying the high velocity transport fluid flow to the working fluid exiting the communicating bores, thereby imparting a shear force on the working fluid and atomizing the working fluid to produce a dispersed droplet flow regime.

22. The method of claim 21, wherein the one or more communicating openings are independently selected from the group consisting of communicating bores, communicating annuli, and combinations thereof.

23. The method of claim 22, wherein the one or more communicating openings are one or more communicating bores.

24. The method of claim 22, wherein the high velocity transport fluid flow is applied substantially perpendicular to the working fluid flow exiting the openings.

25. The method of claim 21, wherein the step of accelerating the first transport fluid is achieved by providing the first transport fluid passage with a convergent-divergent internal geometry and forcing the first transport fluid through the convergent-divergent portion.

26. The method of claim 21, further comprising the steps of:

a) forcing the atomized working fluid from the first transport fluid passage into a second transport fluid passage via one or more second communicating openings extending radially outwardly from the first transport fluid passage;

b) supplying a second transport fluid through the second transport fluid passage;

c) accelerating the second transport fluid upstream of the second communicating openings so as to provide a second high velocity transport fluid flow; and

d) applying the second high velocity transport fluid flow to the atomized working fluid exiting the second communicating openings, thereby imparting a second shear force on the atomized working fluid and further atomizing the working fluid.

27. The method of claim 26, wherein the second high velocity transport fluid flow is applied substantially perpendicular to the atomized working fluid flow exiting the second openings.

29. A fire suppression system comprising a mist generating apparatus that includes:

a) an elongate hollow body; and

b) an elongate member located within the body such that a first transport fluid passage and a nozzle are defined between the body and the elongate member, the first transport fluid passage having a convergent-divergent internal geometry and being in fluid communication with the nozzle, wherein the elongate member includes a working fluid passage and one or more communicating openings extending radially outwardly from the working fluid passage, the openings allowing fluid communication between the working fluid passage and the first transport fluid passage.