INDUSTRIAL BURNER

Abstract

An apparatus and process is provided for combining fuel and combustion air to produce a mixture. The mixture is burned in a combustion chamber to produce a flame.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figures in which:

FIG. 1 is a diagrammatic view of a burner in accordance with the present disclosure showing discharge of (1) a first fuel stream into a stream of air flowing in a first airflow channel to produce a “straight-line” air/fuel mixture flowing through an air/fuel transfer channel into a combustion chamber; (2) a second fuel stream into a stream of “swirling” air flowing in a second airflow channel containing a swirler to produce a “swirling” air/fuel mixture flowing through the air/fuel transfer channel “alongside” the straight-line air/fuel mixture into the combustion chamber; and (3) an auxiliary fluid stream into the combustion chamber, and showing ignition of the straight-line and swirling air/fuel mixtures and the auxiliary fluid stream in the combustion chamber to produce a flame;

FIG. 2 is a perspective exploded assembly view of components included in a burner in accordance with the present disclosure showing several air-swirl vanes mounted in a “pin-wheel” pattern on an exterior surface of a vane-support sleeve surrounding a fuel-supply tube coupled to a fuel supply to provide an annular opening into an inner (first) airflow channel formed between the fuel-supply tube and the vane-support sleeve and showing fuel jet ports formed in a downstream end of each air-swirl vane for emitting streams of fuel into swirling air swirled by the air-swirl vanes;

FIG. 3 is a sectional view of the burner taken along line 3-3 of FIG. 2 after assembly of the components shown in FIG. 1 showing placement of the air-swirl vanes and the vane-support sleeve in an annular space defined between the fuel-supply tube and a surrounding air-supply duct to “split” the air flowing through an air-supply duct toward a combustion chamber formed in a downstream burner cone and sleeve into (1) a “straight-line” air stream flowing in the annular inner (first) airflow channel formed between an exterior surface of the fuel-supply tube and an interior surface of the vane-support sleeve and mixing with fuel streams discharged through a first set of fuel jet ports located in the annular inner first airflow channel and (2) a “swirling” air stream flowing in an annular outer (second) airflow channel (containing a swirler defined by the air-swirl vanes) formed between an exterior surface of the vane-support sleeve and an interior surface of the air-supply duct and mixing with fuel streams discharged through a second set of fuel jet ports formed in the air-swirl vanes to establish a swirling air/fuel mixture surrounding the straight-line air/fuel mixture and cooperating with the straight-line air-fuel mixture (and with an auxiliary fluid stream passing through a small-diameter fluid-injector tube extending through the fuel-supply tube) to establish a combustible air/fuel mixture that flows through an air/fuel transfer channel arranged to extend from the air-swirl vanes to the combustion chamber and located between the exterior surface of the fuel-supply tube and the interior surface of the air-supply duct and ignites in the combustion chamber to produce a stable flame associated with a downstream end of the fuel-supply tube;

FIG. 4 is an enlarged perspective view of the air-supply duct of FIGS. 2 and 3, with portions broken away, showing air flowing from the air plenum through a small-diameter annular opening into the inner (first) airflow channel and through a surrounding large-diameter annular opening into the outer (second) airflow channel and showing discharge of a second stream of fuel through the second set of jet ports to mix with swirling air discharged from the annular outer (second) airflow channel to produce a swirling air/fuel mixture flowing in a spiraling pattern in the downstream air/fuel transfer channel;

FIG. 5 is a perspective view of the air-supply duct of FIG. 4 taken from a different point of view showing the straight-line air/fuel mixture flowing along the cylindrical exterior surface of the fuel-supply tube and showing the swirling air/fuel mixture flowing in a spiraling pattern along the cylindrical interior surface of the air supply tube and around the straight-line air/fuel mixture and showing an auxiliary fluid stream being discharged from a small-diameter fluid-injector tube extending through a downstream end of the larger-diameter fuel-supply tube;

FIG. 6 is a diagrammatic view showing a center circle representing the fuel-supply tube and containing a smaller circle representing the fluid-injector tube, a “small-diameter” annular zone around the fuel-supply tube containing the straight-line air/fuel mixture, a “large-diameter” annular zone surrounding the small-diameter annular zone and containing the swirling air/fuel mixture, and a circular “shear” interface (shown in phantom) between the small-diameter and large-diameter annular zones;

FIG. 7 is a top plan view of the burner shown in FIG. 3, with portions broken away, showing the auxiliary fluid stream flowing from the fluid-injector tube into the combustion chamber, along a “center-line” path through the burner, and showing an “interface” between the straight-line air/fuel mixture flowing through the air/fuel transfer channel into the combustion chamber and the swirling air/fuel mixture surrounding the straight-line air/fuel mixture and flowing in a spiraling pattern through the air/fuel transfer channel into the combustion chamber;

FIG. 8 is an enlarged sectional view taken along line 8-8 of FIG. 3 showing radially outward flow of fuel from the fuel-supply tube through apertures formed in the fuel-supply tube into short radiated first-stage fuel transfer tubes and then into the annular inner (first) airflow channel through fuel jet ports formed in the short radiated first-stage fuel transfer tubes to generate a straight-line air/fuel mixture flowing in the air/fuel transfer channel toward the combustion chamber and showing further radially outward flow of fuel from the short radiated first-stage fuel transfer tube into longer angled second-stage fuel transfer tubes formed in downstream ends of the air-swirl vanes and then into the annular outer (second) airflow channel through fuel jet ports formed in the angled second-stage fuel transfer tubes to generate a “swirling” air/fuel flowing mixture in the air/fuel transfer channel toward the combustion chamber;

FIG. 9 is a sectional view taken along line 9-9 of FIG. 8 showing discharge of fuel through fuel jet ports formed in the short radiated first-stage fuel transfer tubes into the annular inner airflow channel;

FIG. 10 is a sectional view taken along line 10-10 of FIG. 8 showing discharge of fuel through fuel jet ports formed in the longer angled second-stage fuel transfer tubes into the annular outer airflow channel; and

FIG. 11 is a perspective and diagrammatic view showing flow of the swirling air/fuel mixture in a spiraling pattern about the straight-line air/fuel mixture.

Claims

1. An air-fuel combustion system comprising an air/fuel transfer duct adapted to discharge an air-and-fuel mixture into a combustion chamber,an air-supply duct containing a first airflow channel communicating with the air/fuel transfer duct, a separate second airflow channel communicating with the air/fuel transfer duct, and a swirler located in the second airflow channel and configured to swirl combustion air flowing through the second airflow channel, anda fuel-supply duct coupled to the first airflow channel to discharge a first fuel stream generated from fuel flowing in the fuel-supply duct into combustion air flowing in the first airflow channel to product a straight-line air/fuel mixture discharged from the first airflow channel into the air/fuel transfer duct and coupled to the second airflow channel to discharge a second fuel stream generated from fuel flowing in the fuel-supply duct into swirling combustion air flowing in the second airflow channel to produce a swirling air/fuel mixture discharged form the second airflow channel into the air/fuel transfer duct, wherein the air/fuel transfer duct is configured to provide means for conducting the straight-line air/fuel mixture discharged from the first airflow channel and the swirling air/fuel mixture discharged from the second airflow channel to a combustion chamber for combustion therein.

2. The system of claim 1, further comprising injector means for mixing an auxiliary fluid stream with the straight-line air/fuel mixture exiting the air/fuel transfer duct and with the swirling air/fuel mixture exiting the air/fuel transfer duct to produce a combustible mixture ready to be ignited in the combustion chamber to produce a flame, wherein the auxiliary fluid stream comprises at least one of a fuel gas, a liquid fuel, an inert gas, and an oxidant.

3. The system of claim 2, wherein the injector means includes a fluid-injector tube adapted at one end to be coupled to a fluid supply and at an opposite end to communicate with the combustion chamber and formed to include a fluid-conductor passageway means extending therethrough for conducting the auxiliary fluid stream from the fluid supply to the combustion chamber.

4. The system of claim 3, wherein the fluid-injector tube is arranged to extend through the air/fuel transfer duct, the air-supply duct, and the fuel-supply duct to reach the combustion chamber.

5. The system of claim 3, wherein the second airflow channel is arranged to surround the fluid-injector tube and the first airflow channel is arranged to surround the fluid-injector tube and lie in a space located between the fluid-injector tube and the second airflow channel.

6. The system of claim 3, wherein the fluid-injector tube is arranged to extend through the air/fuel transfer duct.

7. The system of claim 3, wherein the air-supply duct is formed to include an air-conductor passageway, the swirler is located in the air-conductor passageway, the fuel-supply duct includes a fuel-supply tube arranged to extend through the air-conductor passageway and formed to include a fuel-conductor passageway extending therethrough, the swirler includes an annular vane-support sleeve formed to include a duct-receiver passageway extending therethrough and receiving a portion of the fuel-supply tube therein and arranged to define a boundary between the first and second airflow channels locating the first airflow channel in a space between an exterior surface of the fuel-supply tube and an interior surface of the vane-support sleeve and the second airflow channel in a space between an exterior surface of the vane-support sleeve and an interior surface of the air-supply duct, and the swirler further includes air-swirl vanes mounted on the exterior surface of the vane-support sleeve, and wherein the fluid-injector tube is arranged to extend through the fuel-conductor passageway of the fuel-supply tube.

8. The system of claim 1, wherein the swirler includes a sleeve formed to include a duct-receiver passageway, a portion of the fuel-supply duct is arranged to extend through the duct-receiver passageway, and the sleeve is arranged to partition a space between an interior surface of the air-supply duct and an exterior surface of the portion of the fuel-supply duct to form the first and second airflow channels in said space.

9. The system of claim 8, wherein the sleeve of the swirler is arranged to define a boundary between the first and second airflow channels locating the first airflow channel in an inner space between the exterior surface of the portion of the fuel-supply duct and an interior surface of the sleeve and the second airflow channel in an outer space between an exterior surface of the sleeve and the interior surface of the air-supply duct.

10. The system of claim 9, wherein the swirler further includes several air-swirl vanes mounted on the exterior surface of the sleeve to lie in the second airflow channel and configured to impart swirling motion to combustion air flowing in the second airflow channel.

11. The system of claim 8, wherein the swirler further includes several air-swirl vanes coupled to the sleeve, arranged to lie in the second air-flow channel, and configured to impart swirling motion to combustion air flowing in the second airflow channel.

12. The system of claim 11, wherein each air-swirl vane has a helical shape and the air-swirl vanes are mounted in a pinwheel pattern on the sleeve.

13. The system of claim 11, wherein the fuel-supply duct includes a fuel sprayer located between the air-swirl vanes and air/fuel transfer duct and configured to provide means for discharging fuel flowing in fuel-supply duct into each of the first and second airflow channels so that a first fuel stream mixes with combustion air flowing in the first airflow channel to produce the straight-line air/fuel mixture and a second fuel stream mixes with combustion air flowing in the second air flow channel to produce the swirling air/fuel mixture.

14. The system of claim 1, wherein the fuel-supply duct includes a fuel sprayer configured to provide means for discharging fuel flowing in fuel-supply duct into each of the first and second airflow channels so that a first fuel stream mixes with combustion air flowing in the first airflow channel to produce the straight-line air/fuel mixture and a second fuel stream mixes with combustion air flowing in the second air flow channel to produce the swirling air/fuel mixture.

15. The system of claim 14, wherein the fuel sprayer includes a first-stage fuel transfer tube located in the first airflow channel and formed to include a passageway therein, the passageway of the first-stage fuel transfer tube is aligned with an aperture formed in the fuel-supply tube to receive fuel discharged from fuel-supply tube through the aperture, and the first-stage fuel transfer tube is formed to include a first-stage side-discharge aperture opening into the first airflow channel to cause the first fuel stream to be discharged therethrough to mix with combustion air flowing in the first airflow channel to produce the straight-line air/fuel mixture.

16. The system of claim 15, wherein the first-stage side-discharge aperture is sized to cause the first fuel stream to be about 10% of the fuel discharged from the fuel supply into the fuel-supply tube.

17. The system of claim 15, wherein a second-stage fuel transfer tube is coupled in fluid communication to an open-ended distal potion of the first-stage fuel transfer tube to receive any fuel flowing therethrough that was not discharged through the first-stage side-discharge aperture into the first airflow channel, the second-stage fuel transfer tube is arranged to extend into the second airflow channel, and the second-stage fuel transfer tube is formed to include at least one second-stage side-discharge aperture opening into the second airflow channel to cause the second fuel stream to be discharged therethrough to mix with swirling combustion air flowing in the second airflow channel to produce the swirling air/fuel mixture.

18. The system of claim 15, wherein a second-stage fuel transfer tube is arranged to extend into the second airflow channel and coupled in fluid communication to first-stage fuel transfer tube to receive any fuel flowing therethrough that was not discharged through the first-stage side-discharge aperture into the first airflow channel and the second-stage fuel transfer tube is formed to include at least one aperture opening into the second airflow channel to cause the second fuel stream to be discharged therethrough to mix with swirling combustion air flowing in the second airflow channel to produce the swirling air/fuel mixture.

19. The system of claim 18, wherein the at least one aperture formed in the second-stage fuel transfer tube is sized to cause the second fuel stream to be about 90% of the fuel discharged from the fuel supply into the fuel-supply tube.

20. The system of claim 14, wherein the swirler includes several air-swirl vanes, each air-swirl vane is provided with an upstream and intercepting air flowing in the air-supply duct toward the swirler and a downstream end facing toward the air/fuel transfer duct, the fuel sprayer includes a first-stage fuel transfer tube located in the first airflow channel and mated in fluid communication with the fuel transfer tube and a second-stage fuel transfer tube arranged to extend into the second airflow channel and mated in fluid communication with the first-stage fuel transfer tube to cause the first-stage fuel transfer tube to interconnect the fuel-supply tube and the second-stage fuel transfer tube in fluid communication, the first-stage fuel transfer tube is formed to include an aperture arranged to discharge a portion of the fuel flowing in the first-stage fuel transfer tube into the first airflow channel to generate the first fuel stream, the second-stage fuel transfer tube is formed to include an aperture arranged to discharge fuel flowing in the second-stage fuel transfer into the second airflow channel to generate the second fuel stream, and the second-stage fuel transfer tube is coupled to the downstream end of one of the air-swirl vanes.

21. The system of claim 20, wherein the first-stage and second-stage fuel transfer tubes cooperate to form fuel discharge means for causing about 10% of fuel discharged from the fuel supply into the fuel-supply tube for delivery to the first-stage fuel transfer tube to flow as a first fuel stream through the aperture formed in the first-stage fuel transfer tube into the first airflow channel and for causing about 90% of fuel discharged from the fuel supply into the fuel-supply tube for delivery to the first-stage fuel transfer tube to flow as a second fuel stream through the aperture formed in the second-stage fuel transfer tube into the second airflow channel.

22. An air-fuel combustion system comprising an air/fuel transfer duct adapted to discharge an air-and-fuel mixture into a combustion chamber,first-stage means for mixing a first fuel stream provided by a fuel supply with a laminar flow of air passing through a first airflow channel to produce a non-swirling straight-line air/fuel mixture entering the air/fuel transfer duct, andsecond-stage means for mixing a second-fuel stream provided by the fuel supply with a swirling flow of air passing through a second airflow channel to produce a swirling air/fuel mixture surrounding the non-swirling straight-line air/fuel mixture and entering the air/fuel transfer duct.

23. The system of claim 22, further comprising a fluid-injector tube adapted to be coupled to a fluid supply and arranged to inject an auxiliary fluid stream into the straight-line and swirling air/fuel mixtures to produce a combustible mixture.

24. A process for generating an air-and-fuel mixture, the process comprising the steps of discharging a first fuel stream into a stream of air flowing in a first airflow channel to produce a non-swirling straight-line air/fuel mixture,discharging a second fuel stream into a stream of swirling air flowing in a second airflow channel to produce a swirling air/fuel mixture, andflowing the swirling air/fuel mixture alongside the non-swirling straight-line air/fuel mixture in an air/fuel transfer channel in a direction toward a combustion chamber to generate an air-and-fuel mixture flowing in the air/fuel transfer channel.

25. The process of claim 25, further comprising the step of passing an auxiliary fluid stream comprising at least one of a fuel gas, a liquid fuel, an oxidant, and an inert through a fluid-injector tube extending through the first airflow channel to combine the auxiliary fluid stream with the air-and-fuel mixture to produce a combustible mixture.

26. The process of claim 24, further comprising the step of constraining the swirling air/fuel mixture to flow along a path surrounding the non-swirling straight-line air/fuel mixture flowing in the sir/fuel transfer channel.

27. The process of claim 26, further comprising the step of flowing an auxiliary fluid stream comprising at least one of a fuel gas, a liquid fuel, an oxidant, and an inert through a space surrounded by the non-swirling straight-line air/fuel mixture to produce a combustible mixture.