Lean premix burner having center gas nozzle

Patent metadata

Field	Value
Publication number	US-9841189-B2
Application number	US-201414169554-A
Country	US
Kind code	B2
Filing date	Jan 31, 2014
Priority date	Jan 31, 2013
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

A lean premix burner has a center fire nozzle, which includes radial gas outlets and a ring of outlets. The gas outlets from the center fire nozzle are fed from a manifold. The center fire gas is controlled separately from the main gas supply, which has several advantages, including enhanced turn down capability.

First claim

The invention claimed is:

1. An improved burner assembly for low NOx combustion, comprising:
a combustion air fan inlet;
a gaseous fuel inlet;
a housing that defines a mixing zone downstream of the combustion air fan inlet and downstream of the gaseous fuel inlet for enabling mixing of fuel and combustion air to form a fuel-air mixture;
a main nozzle assembly for directing the fuel-air mixture;
a gas pilot; and
a nozzle-mix, center gas nozzle including:
a gas manifold having a plurality of outlets oriented radially outward;
plural conduits that are oriented radially, the conduits including front-facing gas outlets, whereby gas from the gas manifold exits the front-facing gas outlets and combustion air is supplied from the combustion air fan inlet;

whereby the gas pilot is configured to initiate combustion of fuel from the nozzle-mix, center gas nozzle and from the main nozzle assembly, whereby the nozzle-mix, center gas nozzle can be ignited or extinguished independent of control of the fuel-air mixture, and whereby a turndown ratio of the burner assembly is greater than 10:1.

2. The burner assembly of claim 1 wherein the gas manifold is an annulus that extends to a front of the nozzle-mix, center gas nozzle, and the conduits extend radially outwardly from the manifold.

3. The burner assembly of claim 1 wherein the plurality of outlets of the gas manifold are located near an outlet of the gas pilot.

4. The burner assembly of claim 1 wherein the gas pilot is located at the center of the main nozzle assembly such that an inner wall of the gas manifold forms a housing for the gas pilot.

5. The burner assembly of claim 1 wherein the main nozzle assembly includes at least one converging cone, spaced radially apart from the housing, for directing the fuel-air mixture, and at least one flame anchor formed by a bluff surface located proximate a front of the nozzle assembly for anchoring the flame.

6. The burner assembly according to claim 5 , wherein the bluff surface is formed proximate a front of the burner assembly and a downstream end is vaneless.

7. The burner assembly of claim 1 wherein the burner is a sealed-in burner.

8. The burner assembly according to claim 1 further comprising a swirl vane assembly for mixing the combustion air with the gaseous fuel upstream of the main nozzle assembly.

9. The burner assembly according to claim 8 wherein a swirling motion imparted by a plurality of inner vanes of the swirl vane assembly is opposite in orientation to a swirling motion imparted by a plurality of outer vanes of the swirl vane assembly.

10. The burner assembly according to claim 1 wherein the burner assembly contains no oil firing capability.

11. The burner assembly according to claim 1 wherein the turndown ratio is between 10:1 and 30:1.

12. The burner assembly according to claim 1 wherein the turndown ratio is between 14:1 and 28:1.

13. The burner assembly according to claim 1 wherein the turndown ratio is between 18:1 and 26:1.

14. The burner assembly according to claim 1 wherein the turndown ratio is greater than 20:1.

Assignees

• Hauck Mfg Co
• Honeywell Int Inc

Inventors

• Wartluft Bruce

Classifications

• F23D14/62

  Mixing devices; Mixing tubes · CPC title

• F23D14/36 Primary

  in which the compressor and burner form a single unit · CPC title

• F23C7/004

  using vanes · CPC title