Turbulent flow cooling for electronic ballast

• US 8,334,640 B2
• Filed: 08/12/2009
• Issued: 12/18/2012
• Est. Priority Date: 08/13/2008
• Status: Active Grant

• Current Assignee: Express Imaging Systems, LLC
• Original Assignee: Express Imaging Systems, LLC
• Inventors: Reed, William G., Renn, John O.
• Primary Examiner(s): Guharay, Karabi
• Assistant Examiner(s): Santonocito, Michael
• Application Number:
  US12/540,250
• Publication Number:
  US 20100090577A1
• Time in Patent Office: 1,224 Days
• Field of Search: 313/35, 313/36, 313/46, 362/373, 362/294
• US Class Current: 313/35
• CPC Class Codes: F21K 9/23 Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
• CPC Class Codes: F21V 23/026 Fastening of transformers or ballasts
• CPC Class Codes: F21V 29/507 of means for protecting lighting devices from damage, e.g. housings
• CPC Class Codes: F21V 29/60 characterised by the use of a forced flow of gas, e.g. air
• CPC Class Codes: F21V 29/67 characterised by the arrangement of fans
• CPC Class Codes: F21V 29/677 the fans being used for discharging
• CPC Class Codes: F21V 29/773 the planes containing the fins or blades having the direction of the light emitting axis
• CPC Class Codes: F21V 29/83 the elements having apertures, ducts or channels, e.g. heat radiation holes
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

An apparatus for heat dissipation for a luminaire comprises an active heat transfer device and a thermally-conductive housing. The active heat transfer device causes turbulence in an ambient fluid. The thermally-conductive housing includes a cavity and a first end. The cavity is structured for an electronic ballast of the luminaire to be housed therein and thermally attached to an interior surface of the housing to allow the housing to absorb at least a portion of heat generated by the electronic ballast. The first end is structured for the active heat transfer device to be mountable to the first end of the housing. The housing further includes at least one thermally-conductive protrusion extending from an exterior surface of the housing and exposed to the turbulence in the ambient fluid to transfer at least a portion of the heat absorbed by the housing to the ambient fluid.

Claims

1. An apparatus for heat dissipation for a luminaire, comprising:

a thermally-conductive housing having an exterior surface, an interior surface that forms a cavity, a first end with an opening to provide access to the cavity from an exterior of the housing, and a plurality of thermally-conductive protrusions that extend from the exterior surface of the housing and exposed to an ambient fluid on the exterior of the housing to at least one of convectively or radiantly thermally transfer heat from the housing to the ambient fluid on the exterior of the housing;

an electronic ballast mounted in the cavity of the housing and thermally conductively coupled to the interior surface of the housing to allow the housing to at least conductively absorb at least a portion of heat generated by the electronic ballast during use, and

an active heat transfer device mounted at least proximate the first end of the housing to sealingly enclose the electronic ballast in the cavity of the housing at least during use and operable to cause turbulence in the ambient fluid on the exterior of the housing at least about the thermally-conductive protrusions to enhance convective transfer of heat to the ambient fluid from the plurality of thermally conductive protrusions.

2. The apparatus of claim 1 wherein the active heat transfer device comprises:

a heat sink to which a light source of the luminaire is conductively coupled for the heat sink to absorb at least a portion of heat generated by the light source; and

an active cooler coupled to the heat sink and operable to cause turbulence in the ambient fluid when powered.

3. The apparatus of claim 1 wherein the active heat transfer device comprises at least one opening and is operable to eject turbulent flow from the at least one opening.

4. The apparatus of claim 3 wherein the plurality of thermally-conductive protrusions that extend from the exterior surface of the housing comprise a plurality of fins, and wherein each of the fins has at least two surfaces and is aligned with a respective one of the at least one opening of the active heat transfer device when the active heat transfer device is mounted to the housing so that the turbulent flow ejected from each of the at least one opening of the active heat transfer device flows over at least one of the at least two surfaces of a respective one of the fins.

5. The apparatus of claim 1 wherein the thermally-conductive housing comprises at least one type of metal.

6. The apparatus of claim 1 wherein the electronic ballast is bonded to the thermally-conductive housing with a thermally-conductive adhesive.

7. The apparatus of claim 1 wherein the electronic ballast is mechanically secured to the thermally-conductive housing.

8. The apparatus of claim 1 wherein the luminaire comprises a solid-state luminaire that emits light using a solid-state device.

9. The apparatus of claim 1, wherein the plurality of thermally-conductive protrusions that extend from the exterior surface of the housing includes a plurality of thermally-conductive protrusions extending from the exterior surface of the first end of the housing and not from a second end of the housing opposite the first end.

10. The apparatus of claim 1 wherein the active heat transfer device comprises:

a heat sink; and

an active cooler coupled to the heat sink and operable to cause turbulence in the ambient fluid when powered, the apparatus further comprising;

a number of solid-state light sources carried by the heat sink and thermally conductively coupled thereto.

11. The apparatus of claim 10 wherein the active heat transfer device comprises at least one opening through which turbulent flow is ejected into the ambient fluid when the active cooler is powered and the at least one opening is positioned relatively forward of the thermally-conductive protrusions with respect to a direction into which light is emitted by the solid-state light sources.

12. A method of actively cooling an electronic ballast of a luminaire, the method comprising:

providing a thermally-conductive housing having an exterior surface, an interior surface that forms a cavity to house the electronic ballast of the luminaire therein, the housing having a first end with an opening to provide access to the cavity from an exterior of the housing, and a plurality of thermally-conductive protrusions extending from the exterior surface of the housing;

thermally coupling the electronic ballast to the housing to promote at least a portion of heat generated by the electronic ballast to be transferred to the housing and the plurality of thermally-conductive protrusions of the housing;

mounting an active heat transfer device to the housing at least proximate the first end of the housing to sealingly enclose the electronic ballast in the housing; and

causing turbulence in an ambient fluid at least surrounding the plurality of protrusions of the housing to enhance convective transfer of heat to the ambient fluid from the plurality of protrusions.

13. The method of claim 12 wherein causing turbulence in the ambient fluid surrounding the plurality of protrusions of the housing comprises causing turbulence in the ambient fluid surrounding the plurality of protrusions of the housing by an active cooler that is coupled to the housing.

14. The method of claim 12 wherein the plurality of protrusions of the housing comprises a plurality of thermally-conductive fins.

15. The method of claim 12 wherein thermally coupling the electronic ballast to the housing comprises bonding the electronic ballast to the housing with a thermally-conductive adhesive.

16. The method of claim 12 wherein thermally coupling the electronic ballast to the housing comprises mechanically securing the electronic ballast to the housing.

17. The method of claim 12, further comprising providing power to a solid-state device of the luminaire that emits light in response.