LOW NOISE NOZZLE ASSEMBLY FOR FIRE SUPPRESSION SYSTEM

Abstract

A nozzle assembly for a fire suppression system is disclosed, which includes a body having an inlet end for receiving a flow of fire extinguishing agent from the fire suppression system at an inlet pressure, a nozzle portion extending from the body and having an interior cavity defining a central axis, wherein a plurality of exit orifices are formed in an outer wall of the nozzle portion, in communication with the interior cavity, for vectoring the flow of fire extinguishing agent exiting therefrom and to reduce a noise level of the nozzle assembly, and at least one perforated filter member positioned upstream from the exit orifices in the nozzle portion, for reducing the inlet pressure of the fire extinguishing agent in furtherance of noise level reduction.

Claims

1. A nozzle assembly for a fire suppression system, comprising: a) a body having an inlet end for receiving a flow of fire extinguishing agent from the fire suppression system at an inlet pressure; b) a nozzle portion extending from the body and having an interior cavity, wherein a plurality of exit orifices are formed in an outer wall of the nozzle portion, in communication with the interior cavity, for vectoring the flow of fire extinguishing agent exiting therefrom; and c) at least one perforated filter member positioned upstream from the exit orifices formed in the nozzle portion, for reducing the inlet pressure of the fire extinguishing agent.

2. A nozzle assembly as recited in claim 1, wherein the at least one perforated filter member is formed from a perforated metal plate.

3. A nozzle assembly as recited in claim 2, wherein the at least one perforated filter member has about between 20% to 40% open area as defined by a multiplicity of perforations.

4. A nozzle assembly as recited in claim 3, wherein the at least one perforated filter member is formed from an aluminum plate that has about 23% open area as defined by a multiplicity of perforations.

5. A nozzle assembly as recited in claim 1, wherein the at least one perforated filter member includes a plurality of perforated filter members positioned within the interior cavity of the nozzle portion in spaced apart relationship along a central axis thereof.

6. A nozzle assembly as recited in claim 5, wherein each of the plurality of perforated filter members has the same porosity.

7. A nozzle assembly as recited in claim 5, wherein each of the plurality of perforated filter members has a different porosity.

8. A nozzle assembly as recited in claim 7, wherein the plurality of perforated filter members decrease in porosity in a downstream direction along the central axis of the nozzle portion.

9. A nozzle assembly as recited in claim 1, wherein a porous metal foam insert is positioned upstream from the at least one perforated filter member.

10. A nozzle assembly as recited in claim 1, wherein the inlet end of the body portion includes a metering orifice.

11. A nozzle assembly as recited in claim 1, wherein the inlet end of the body portion is axially aligned with the nozzle portion along a central axis thereof.

12. A nozzle assembly as recited in claim 11, wherein the nozzle portion has a conical outer wall, and wherein the exit orifices are defined in the conical outer wall of the nozzle portion.

13. A nozzle assembly as recited in claim 12, wherein a cross-sectional area of the nozzle portion at any axial point along the central axis thereof is equal to a total open area of the exit orifices formed in the conical outer wall of the nozzle portion downstream from that axial point.

14. A nozzle assembly as recited in claim 12, wherein the exit orifices formed in the conical outer wall of the nozzle portion are oriented at an angle that is perpendicular to the central axis of the nozzle portion.

15. A nozzle assembly as recited in claim 12, wherein the exit orifices formed in the conical outer wall of the nozzle portion are oriented at an angle that is perpendicular to a local wall angle of the nozzle portion.

16. A nozzle assembly as recited in claim 12, wherein the exit orifices formed in the conical outer wall of the nozzle portion vary in diameter along the central axis of the nozzle portion in a downstream direction.

17. A nozzle assembly as recited in claim 1, wherein the nozzle portion has a cylindrical configuration with an outer peripheral wall, and wherein the exit orifices are defined in the outer peripheral wall of the cylindrical nozzle portion.

18. A nozzle assembly as recited in claim 17, wherein turning vanes are provided between the inlet end of the body portion and the exit orifices in the peripheral outer wall of the cylindrical nozzle portion to redirect flow.

19. A nozzle assembly as recited in claim 17, wherein the at least one perforated filter member is a cylindrical perforated filter member that is coaxially positioned within the cylindrical nozzle portion.

20. A nozzle assembly as recited in claim 19, wherein a plurality of coaxially spaced apart perforated filter members is positioned within the cylindrical nozzle portion.

21. A nozzle assembly for a fire suppression system, comprising: a) a body having an inlet end for receiving a flow of fire extinguishing agent from the fire suppression system at an inlet pressure; b) a nozzle portion axially aligned with the inlet end of the body along a central axis thereof, wherein a plurality of exit orifices are formed in a conical outer wall of the nozzle portion for vectoring the flow of fire extinguishing agent exiting therefrom, wherein a cross-sectional area of the nozzle portion at any axial point along the central axis thereof is equal to a total open area of the exit orifices formed in the conical outer wall of the nozzle portion downstream from that axial point.

22. A nozzle assembly as recited in claim 21, wherein at least one perforated filter member is positioned upstream from the exit orifices formed in the nozzle portion, for reducing the inlet pressure of the fire extinguishing agent.

23. A nozzle assembly as recited in claim 22, wherein a porous metal foam insert is positioned upstream from the at least one perforated filter member.

24. A nozzle assembly as recited in claim 22, wherein a metering orifice is positioned upstream from the at least one perforated filter member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] So that those skilled in the art will readily understand how to make and use the low velocity acoustic reduction nozzle of the subject invention without undue experimentation, embodiments thereof will be described in detail herein below with reference to the figures wherein:

[0014] FIG. 1 is a perspective view of a server room in a data center that is protected by a fire suppression system including a low-velocity nozzle configured in accordance with an embodiment of the subject invention;

[0015] FIG. 2 is a perspective view of a preferred embodiment of the low-velocity nozzle of the invention;

[0016] FIG. 3 is a cross-sectional view of the nozzle of the preferred embodiment taken along line 3-3 of FIG. 2;

[0017] FIG. 4 is a cross-sectional view of the nozzle of an alternative embodiment of the invention;

[0018] FIG. 5 is a cross-sectional view of the nozzle of another alternative embodiment of the invention;

[0019] FIG. 6 is a cross-sectional view of the nozzle of another alternative embodiment of the invention;

[0020] FIG. 7 is a front plan view of a perforated filter member in the form of a perforated metal plate having a multiplicity of perforations;

[0021] FIG. 8 is a perspective view of another embodiment of the low noise nozzle of the subject invention; and

[0022] FIG. 9 is a cross-sectional view taken alone line 9-9 of FIG. 8, showing the interior of the nozzle of FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

[0023] A nozzle for a fire suppression system that produces lower noise levels would protect data centers without risk of lost operation time. Referring now to the drawings wherein like reference numerals identify similar structural elements and features of the subject invention, there is illustrated in FIG. 1 a server room 10 located in a data center 12, which houses racks 14 containing hard disk drives 16, and a fire suppression system 18 for protecting the server room 10 in the event of the detection of a hazardous condition such as smoke, excessive heat or fire. The fire suppression system 18 includes a storage tank 15 containing an inert gas fire suppressant, such as argon. The fire suppression system 18 further includes one or more low-velocity acoustic noise reduction nozzle assemblies constructed in accordance with an embodiment of the invention and designated generally by reference numeral 20 for discharging the fire suppressant contained in storage tank 15 into the server room 10 in the event of the detection of a hazardous condition.

[0024] FIG. 2 illustrates a perspective view of a preferred low-velocity nozzle. The nozzle assembly 20 of the subject invention includes a body 22 having an inlet end 23 for receiving a flow of fire extinguishing agent from the fire suppression system 18 at a particular entrance mass flow of about between 0.1 and 0.5 kg/s (e.g., 0.3 kg/s) and inlet pressure of about between 60 to 70 psig (e.g., 66 psig). The body 22 of nozzle assembly 20 further includes an axially extending nozzle portion 24. A plurality of exit orifices 28 are formed through the nozzle portion 24 for efficiently vectoring the flow of fire extinguishing agent exiting therefrom as described below.

[0025] FIG. 3 illustrates a cross-sectional view of the nozzle taken along line 3-3 of FIG. 2. The axially extending nozzle portion 24 of nozzle assembly 20 has a conical outer wall 25 and an interior cavity 26 that defines a central longitudinal axis extending along line X-X in upstream direction U.sub.s and downstream direction D.sub.s. A plurality of exit orifices 28 are formed in the conical outer wall 25 of nozzle portion 24 for efficiently vectoring the flow of fire extinguishing agent exiting therefrom and to effectively reduce the acoustic noise level of the nozzle assembly 20. Moreover, the exit orifices 28 formed in the conical outer wall 25 of nozzle portion 24 help to reduce the overall acoustic signature of the nozzle assembly 20.

[0026] A perforated filter member 30 is positioned within the interior cavity 26 of the nozzle portion 24, upstream from the exit orifices 28 formed in the conical outer wall 25, for reducing the entrance velocity of the fire extinguishing agent, in furtherance of acoustic noise level reduction. Moreover, the perforated filter member 30 described in further detail below functions to lower the pressure of the incoming flow before entering the nozzle portion 24, dropping the inlet pressure by about 60 psig to a preferred exit pressure of about 2 psig to avoid supersonic jet flow through the nozzle assembly 20.

[0027] As a result of the perforated filter member 30 advantageously lowering the velocity and pressure of the incoming flow of fire suppressant, in combination with the exit orifices 28 lowering the acoustic signature of the nozzle assembly 20, the nozzle assembly has a resulting noise level of less than 110 db. Those skilled in the art will readily appreciate that achieving such a noise level will not cause damage or disruption to the HDDs 16 that are located within the server room of a data center 12 in the event of a fire.

[0028] The perforated filter member 30 is in the form of a perforated metal plate, which is best seen in FIG. 7. The perforated metal plate of filter member 30 is preferably made from aluminum or a similar light-weight metal having a thickness of about 1/16.sup.th of an inch. Preferably, about 20% to 40% of the surface area of the perforated filter member 30 is defined by open space. For example, the perforated filter member 30 may be defined by about 23% open space formed by a multiplicity of apertures 35.

[0029] With continuing reference to FIG. 3, the inlet end 23 of the body 22 of nozzle assembly 20 includes a threaded flange 32, which is configured for operative engagement with a threaded fitting 34. The threaded fitting 34 has a conventional NPT format that is adapted to communicate with the fire suppression system 18 and it includes a metering orifice plate 37. The filter member 30 is supported or otherwise firmly retained within the interior cavity 26 of the body 22 of nozzle assembly 20, sandwiched between an interior abutment surface 36 of the body 22 and a leading edge 38 of the threaded fitting 34.

[0030] In the embodiment of FIG. 3, the exit orifices 28 defined in the conical outer wall 25 of the nozzle portion 24 are oriented at an angle α.sub.1 that is perpendicular to the local wall angle of the conical outer wall 25 of nozzle portion 24 to control fluid vectoring. Alternatively, as shown in FIG. 4, the exit orifices 28 defined in the conical outer wall 25 of the nozzle portion 24 can be oriented at an angle α.sub.2 that is perpendicular to the central axis X-X of the nozzle portion 24 so as to control fluid vectoring in a different manner.

[0031] Alternatively, the exit orifices 28 can be oriented at other angles ranging from the orientation shown in FIG. 3 to the orientation shown in FIG. 4, so as to control fluid vectoring in another preferred manner, which would depend upon the configuration of the area to be protected by the nozzle assembly 20. It is also envisioned that the exit orifices 28 in the conical outer wall 25 of the nozzle portion 24 could vary in diameter and/or in number along the central axis X-X of the nozzle portion 24. For example, the upstream exit orifices 28 can have a diameter “D” while the downstream exit orifices 28 can have a smaller diameter “d” as illustrated in FIG. 5

[0032] Those skilled in the art will readily appreciate that the frequency of the noise generated by the nozzle assembly 20 will increase as the exit orifices 28 decrease in size. Accordingly, the diameter of the exit orifices 28 should be sized so as to minimize the overall acoustic signature of the nozzle assembly 20, while maintaining a preferred coverage volume of about 100 m.sup.3.

[0033] Furthermore, the nozzle portion 24 is preferably dimensioned and configured so that the cross-sectional area thereof at any point along the central axis X-X is equal to the total open area of the exit orifices 28 formed in the conical outer wall 25 of the nozzle portion 24 downstream from that point. Consequently, the static pressure within the interior cavity 26 of the nozzle portion 24 will be maintained at a level that will ensure that fire extinguishing agent is uniformly fed to all of the exit orifices 28 for the entire duration of the discharge, which could range from 60 seconds to 120 seconds.

[0034] While the nozzle assembly 20 is illustrated in FIGS. 3-5 is shown with only one perforated filter member 30 positioned within the interior cavity 26 of nozzle portion 24, it is envisioned that the nozzle assembly 20 could include a two or more perforated filter members in spaced apart relationship along the central axis X-X thereof. For example, as best seen in FIG. 6, the nozzle assembly 20 could have two of spaced apart filter members, including a downstream perforated filter member 30a positioned within the interior cavity 26 and an upstream perforated filter member 30b positioned within the threaded fitting 34.

[0035] Furthermore, a porous metal foam insert could be associated with an upstream side of each of the perforated filter members 30a and 30b to further reduce the inlet pressure of the fire suppressant. More particularly, a porous metal foam insert 40a would be associated with an upstream side of perforated filter member 30a and a porous metal foam insert 40b would be associated with an upstream side of perforated filter member 30b. When it is present in the nozzle assembly 20, the porous metal foam inserts are about 0.5 inches in thickness. When used alone or in combination with one another, these porous components function to reduce the pressure while evenly distributing the flow throughout the cross-sectional area, and reducing the noise associated with flow turbulence. When the porous components/perforated metal foam are used just downstream of a metering orifice (see element 37 in FIG. 3), they may function to effectively reduce the noise associated with supersonic flow by dissipating the shock formed downstream of the metering orifice.

[0036] While the perforated filter members 30a and 30b preferably have the same porosity, it is envisioned that each of a plurality of perforated filter members could have a different porosity. For example, in such an embodiment, the perforated filter members 30a and 30b would decrease in porosity in a downstream direction D.sub.s along the axis X-X of the interior cavity 26. Thus, the upstream filter member 30a could be a perforated metal plate having a porosity of about 40% and the downstream filter member 30b could be a perforated metal plate having a porosity of about 30%, so as to gradually or otherwise progressively reduce the flow velocity of the fire suppression agent in a stepwise or multi-staged manner. It is also envisioned that the porosity of the upstream filter member 30a and the downstream filter member 30b could be the same.

[0037] Referring now to FIGS. 8 and 9, there is illustrated another embodiment of the low velocity noise reduction nozzle of the subject invention that is designated generally by reference numeral 50. Nozzle assembly 50 is designed for use in a server room 12 of a data center 10 where there are height limitation issues, and it is configured to efficiently vector a flow of fire extinguishing agent in a 360 degree cylindrical pattern.

[0038] With continuing reference to FIG. 8, nozzle assembly 50 includes a cylindrical body portion 52 having a threaded inlet end 54 for receiving fire suppressant agent from a fire suppressant system at a particular entrance mass flow and inlet pressure. Nozzle assembly 50 further includes a cylindrical nozzle portion 60 that has an outer peripheral wall 56 having a plurality of exit orifices 58 formed therein, which are oriented at a preferred angle α.sub.1 relative to an axial plane X-X of nozzle portion 60 for fluid vectoring, as shown in FIG. 9. It is envisioned that the exit orifices 58 in the outer wall 56 could all be oriented at the same angle or at they could be oriented at different angles relative to the axial plane X-X of the nozzle portion 60.

[0039] The inlet end 54 of the body portion 52 of nozzle assembly 50 includes a metering orifice 64, a porous metal foam insert 66 downstream from the metering orifice 64, and a perforated filter member 68 of the type shown in FIG. 7, downstream from the porous metal foam insert 64. In combination, these components function to initially reduce the entrance pressure of the fire extinguishing agent.

[0040] Referring to FIG. 9, turning vanes 70 are provided within the nozzle portion 60 of nozzle assembly 50 between the inlet end 54 of the body portion 52 and the exit orifices 58 in outer wall 56 to direct the flow of fire suppressant and reduce internal noise caused by turbulence. One or more coaxially arranged perforated filter members are also positioned within the cylindrical nozzle portion 60, downstream from the central turning vanes 70 and upstream from the outer peripheral wall 56 for reducing the entrance pressure of the fire extinguishing agent, in furtherance of noise level reduction. More particularly, as shown in FIG. 9, three coaxially arranged perforated filter members 80a-80c are positioned within nozzle portion 60, separated by a plurality of annular upper and lower spacer rings 82a-82d.

[0041] While the subject disclosure has been shown and described with reference to various embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the scope of the subject disclosure.