Low NOx Burner with Low Pressure Drop

• US 20150153041A1
• Filed: 02/06/2015
• Published: 06/04/2015
• Est. Priority Date: 10/03/2013
• Status: Active Grant

• Current Assignee: Plum Combustion, Inc.
• Original Assignee: Plum Combustion, Inc.
• Inventors: Neumeier, Yedidia
• Granted Patent: US 9,371,992 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F23D 14/02 Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone
• CPC Class Codes: F23D 14/62 Mixing devices; Mixing tubes
• CPC Class Codes: F23D 14/70 Baffles or like flow-disturbing devices
• CPC Class Codes: F23D 2900/14021 Premixing burners with swirling or vortices creating means for fuel or air

Abstract

A burner includes a cylindrical tube that terminates in a burner discharge end. An annular disk, affixed to the discharge end, defines a hole. An oxidizer intake delivers oxidizer into the tube. A fuel nozzle delivers fuel into the tube. A cylindrical slotted member has an interrupted outer surface and is disposed within a portion of the tube. The slotted member is affixed to the annular disk and defines an interior void that opens to the hole. The tube and the slotted member define an annular passage therebetween. Elongated slots pass through the outer surface of the slotted member, each directed along a different non-diametrical chord of the slotted member. The elongated slots direct a gaseous stream into the interior void so as to impart both an inwardly-directed radial velocity component and a tangential velocity component to the gaseous stream.

Claims

1. A burner for burning a fuel in a gaseous oxidizer stream, comprising:

(a) a tube, having an inner dimension, configured to allow passage therethrough of the gaseous stream, a selected end of the tube terminating in a burner discharge end;

(b) a front disk affixed to the burner discharge end of the tube, the front disk defining a hole therethrough;

(c) an oxidizer intake configured to deliver the oxidizer into the tube;

(d) a fuel nozzle configured to deliver the fuel into the tube, the fuel nozzle including a fuel pipe defining an interior space and terminating in an end portion, the fuel pipe defining a plurality of orifices adjacent the end portion and passing therethrough, a corresponding plurality of hollow tubes extending radially outwardly therefrom, each of the plurality of hollow tubes in fluid communication with the interior space defined by the fuel pipe and configured to deliver fuel from the interior space defined by the fuel pipe into the tube; and

(e) a slotted member, having an interrupted outer surface having an outer dimension and a length, disposed within a portion of the tube and affixed to the front disk, the slotted member defining an interior void therein that opens to the hole defined by the front disk, the outer dimension being less than the inner dimension of the tube thereby defining an passage therebetween, a plurality of elongated slots defined through the outer surface of the slotted member along the length of the slotted member, each slot directed along a different non-diametrical chord of the slotted member and fluidly coupling the interior void to the passage so that the plurality of elongated slots direct the gaseous stream from the tube into the interior void of the slotted member so as to impart both an inwardly-directed radial velocity component and a tangential velocity component to the gaseous stream.

2. The burner of claim 1, wherein the front disk defines a plurality of elongated slits, each elongated slit directed along a different non-diametrical chord of the front disk, and wherein the slotted member comprises:

(a) a plurality of elongated sheet metal blades, each of which having a front end and an opposite back end, the front end of each elongated sheet metal blade engaged in a different one of the elongated slits defined by the front disk so that each two adjacent ones of the sheet metal blades define one of the slots therebetween;

(b) a back wall that is coupled to the back end of each one of the plurality of elongated sheet metal blades; and

(c) a mechanism configured to maintain each of the plurality of elongated sheet metal blades engaged with the front disk and the back wall.

3. The burner of claim 1, further comprising a cylindrical sleeve, concentric with and disposed about the tube.

4. The burner of claim 1, wherein the end portion of the fuel pipe is disposed outside of the slotted member and inside the tube so that fuel and the oxidizer premix in the gaseous stream prior to the gaseous stream entering the slotted member.

5. The burner of claim 1, wherein the end portion is disposed inside of the interior void defined by slotted member and inside the tube so that fuel and the oxidizer mix in the gaseous stream inside the slotted member.

6. The burner of claim 5, wherein the fuel nozzle is configured to be adjustably moved axially with respect to the cylindrical slotted member.

7. The burner of claim 5, wherein the fuel nozzle further comprises a mechanism that injects fuel into the tube outside of the slotted member so that a portion of the fuel enters the gaseous stream outside of the slotted member and so that another portion of the fuel enters the gaseous stream inside of the slotted member.

8. The burner of claim 1, wherein the oxidizer comprises air.

9. The burner of claim 1, wherein the fuel comprises a burnable gas.

10. The burner of claim 1, wherein the tube is substantially cylindrical and wherein the slotted member is substantially cylindrical and is coaxial with the tube.

11. A burner for burning a fuel in a gaseous oxidizer stream, comprising:

(a) a tube, having an inner dimension, configured to allow passage therethrough of the gaseous stream, a selected end of the tube terminating in a burner discharge end;

(b) a front disk affixed to the burner discharge end of the tube, the front disk defining a hole therethrough, wherein the front disk defines a plurality of elongated slits, each elongated slit directed along a different non-diametrical chord of the front disk;

(c) an oxidizer intake configured to deliver the oxidizer into the tube;

(d) a fuel nozzle configured to deliver the fuel into the tube; and

(e) a slotted member, having an interrupted outer surface having an outer dimension and a length, disposed within a portion of the tube and affixed to the front disk, the slotted member defining an interior void therein that opens to the hole defined by the front disk, the outer dimension being less than the inner dimension of the tube thereby defining an passage therebetween, a plurality of elongated slots defined through the outer surface of the slotted member along the length of the slotted member, each slot directed along a different non-diametrical chord of the slotted member and fluidly coupling the interior void to the passage so that the plurality of elongated slots direct the gaseous stream from the tube into the interior void of the slotted member so as to impart both an inwardly-directed radial velocity component and a tangential velocity component to the gaseous stream, the slotted member including;

a plurality of elongated sheet metal blades, each of which having a front end and an opposite back end, the front end of each elongated sheet metal blade engaged in a different one of the elongated slits defined by the front disk so that each two adjacent ones of the sheet metal blades define one of the slots therebetween;

a back wall that is coupled to the back end of each one of the plurality of elongated sheet metal blades; and

a mechanism configured to maintain each of the plurality of elongated sheet metal blades engaged with the front disk and the back wall.

12. The burner of claim 11, wherein the fuel nozzle includes a fuel pipe defining an interior space and terminating in an end portion, the fuel pipe defining a plurality of orifices adjacent the end portion and passing therethrough, a corresponding plurality of hollow tubes extending radially outwardly therefrom, each of the plurality of hollow tubes in fluid communication with the interior space defined by the fuel pipe and configured to deliver fuel from the interior space defined by the fuel pipe into the tube.

13. The burner of claim 12, further comprising a cylindrical sleeve, concentric with and disposed about the tube.

14. The burner of claim 12, wherein the end portion of the fuel pipe is disposed outside of the slotted member and inside the tube so that fuel and the oxidizer premix in the gaseous stream prior to the gaseous stream entering the slotted member.

15. The burner of claim 12, wherein the end portion is disposed inside of the interior void defined by slotted member and inside the tube so that fuel and the oxidizer mix in the gaseous stream inside the slotted member.

16. The burner of claim 15, wherein the fuel nozzle is configured to be adjustably moved axially with respect to the cylindrical slotted member.

17. The burner of claim 15, wherein the fuel nozzle further comprises a mechanism that injects fuel into the tube outside of the slotted member so that a portion of the fuel enters the gaseous stream outside of the slotted member and so that another portion of the fuel enters the gaseous stream inside of the slotted member.

18. The burner of claim 12, wherein the oxidizer comprises air.

19. The burner of claim 12, wherein the fuel comprises a burnable gas.

20. The burner of claim 12, wherein the tube is substantially cylindrical and wherein the slotted member is substantially cylindrical and is coaxial with the tube.