Multi-Cone Fuel Burner Apparatus For Multi-Tube Heat Exchanger
Installed in a fuel-fired heating appliance is a specially designed burner assembly operative to receive and combust a pre-mixed flow of fuel and air to create therefrom a spaced apart plurality of flames which are aligned with and flow directly into the inlets of a corresponding spaced plurality of heat exchanger tubes. The flames create within the tubes hot combustion gases that transfer combustion heat to a supply fluid flowed externally across the tubes. The burners are of a hollow perforate metal construction, are mounted on and forwardly project from a support structure toward the tube inlets, and have rearwardly facing open inlet ends that receive the pre-mixed flow of fuel and air. In one illustrated embodiment thereof, the burners have conical configurations, and in another illustrated embodiment have generally dome-shaped configurations. Via a flame carryover structure, a single igniter is utilized to ignite all of the burners.
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The present invention relates generally to fuel-fired heating appliances, such as air heating furnaces, and more particularly provides specially designed combustion apparatus for such fuel-fired heating appliances.
In fuel-fired heating appliances such as, for example, air heating furnaces, a known firing method is to flow a fuel/air mixture into a burner box structure in which a burner structure and an associated igniter structure are disposed and are operative to combust the fuel/air mixture and thereby create hot combustion gases used to heat air (or another fluid as the case may be) for delivery to a location served by the heating appliance. The hot combustion gases are flowed through a series of heat exchanger tubes, externally across which the fluid to be heated is flowed, and then discharged from the heating appliance into a suitable flue structure.
Typically, spaced apart open inlet portions of the heat exchanger tubes extend through openings in a wall of the burner box that faces the burner structure which, in a conventional form thereof, is an elongated flat or curved single mesh burner.
A spaced plurality of heat exchanger tubes 22 (representatively five in number) extend through the interior of the heat exchange housing 14 and have open rear inlet ends 24 supported in corresponding openings in the rear wall 18 of the heat exchange housing 14, and open front outlet ends 26 supported in corresponding openings in the rear wall 20 of the collector box 16. As can be seen in
Referring now additionally to
During firing of the heating appliance with which the burner 32 is associated, a flow 40 of pre-mixed fuel and air is forwardly drawn through the burner box 12 to the burner 32 at which point the flow 40 is combusted by the igniter 38 to form along an elongated reaction flame pattern 42 emanating from the front side of the burner 32. As can be seen in
During firing of the conventional combustion section 10, air 46 (or other fluid as the case may be) is suitably flowed externally across the heat exchanger tubes 22 to create heated air 48 for delivery to a conditioned space served by the heating appliance. Simultaneously, the draft inducer fan 30 draws cooled combustion gases 50 from the heat exchanger tube outlet ends 26, through the interior of the collector box 16, and then exhausts the cooled combustion gases 50 to a suitable flue.
A variety of well known problems, limitations and disadvantages are present in this conventional design of a premixed fuel/air combustion system and are primarily created by the use of the flat burner 32. For example, in this application, the negative pressure created by the draft inducer fan 30 tends to forwardly bow the heated burner 32 to its dashed line orientation shown in
Additionally, the flat burner 32, by virtue of presenting a fairly large single combustion zone within the burner box 12, causes a large amount of the created combustion products to exist within and heat up the burner box 12 prior to being drawn through the heat exchanger tubes 22 by the draft inducer fan 30. High temperatures inside the heating appliance cabinet is not desirable because it can cause problems for the other components and it also is a form of efficiency reducing heat loss. Moreover, the flat burner 32 has been found to often be a primary source of an undesirable source of operating noise, including ignition noise, structural vibration noise and steady state high frequency noise. Replacing the flat burner 32 with a curved single burner has been found to at least somewhat alleviate the bowing problem of the flat burner, but still can create an unacceptably large level of operational noise when used in a premixed fuel/air combustion application.
As can be readily seen from the foregoing, a need exists for improved premixed fuel/air combustion apparatus for use in fuel-fired heating appliances. It is to this need that the present invention is primarily directed.
Cross-sectionally depicted in schematic form in
The combustion section 62 comprises, from left to right in
A spaced plurality of heat exchanger tubes 78 (representatively five in number) extend through the interior of the heat exchange housing 68 and have open rear inlet ends 80 supported in corresponding openings in the rear wall 74 of the heat exchange housing 68, and open front outlet ends 82 supported in corresponding openings in the rear wall 84 of the collector box 70. The open rear inlet ends 80 of the heat exchanger tubes 78 are interdigitated with imperforate sections 86 of the rear heat exchange housing wall 74. A draft inducer fan 88 is operatively positioned as shown in the collector box 70.
With reference now to
The burner assembly 90 further includes five hollow metal mesh cone-shaped burners 106 pressed, apexes first, forwardly through the circular openings 102, and projecting forwardly beyond the front support plate side 98 along cone axes 108. After the burners 106 are positioned in the circular support plate openings 102, they are retained therein by placing the backing member 94 on the rear side 100 of the support plate 92 and securing the mounting frame 96 to a peripheral portion of the support plate 92, as with suitable fasteners 110. As later described herein, the conical burners 106 are lit by a suitable igniter 112 illustratively positioned between the bottom two burners 106 as viewed in
Turning now to
During firing of the furnace 60, an initially pre-mixed flow 122 is forwardly drawn by the draft inducer fan 88 through the interior of the mixing box 64 and into the interior of the burner box 66 via the plate perforations 124 to form further mixed flows 126 of the fuel/air mixture that in turn are drawn forwardly into the interiors of the burner cones 106. The flows 126 of fuel/air mixture entering the burner cones 106 are combusted to create at the burner cones 106 a spaced series of individual flames 128 that are interdigitated with the imperforate sections 86 of the rear wall 74 of the heat exchanger housing 68 and enter the heat exchanger tube inlets 80.
Referring now to
The use of the specially designed multi-cone burner assembly 90 provides several advantages over the conventional single elongated flat burner 32 shown in
Moreover, the reduction of combustion heat transfer to the burner box 66 diminishes the potential damage to other components of the heating appliance 60 due to combustion heat transferred thereto. Additionally, the cone burners 106 of the present invention, due to their hollow, forwardly projecting configurations, are substantially more dimensionally stable when being fired than the conventional flat burner 32 shown in
The forward extension of the hollow burner cones 106 beyond their supporting structure increases the total active burner surface beyond that of a corresponding number of flat circular burners used in place of the cone burners 106. Accordingly the cone burners 106 may be sized to provide generally the same overall burner area of a corresponding single flat burner (such as the flat burner 32 in
While the burners 106 shown in
With reference now to
The foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims.
Claims
1. Fuel-fired heating apparatus comprising:
- a housing having an interior, a rear inlet end, and a front outlet end;
- a plurality of heat exchanger tubes having spaced apart inlets communicating with the interior of the housing at the front outlet end of the housing, and outlets;
- a burner assembly supported within the housing and including: a support structure disposed rearwardly of the heat exchanger tube inlets and having a spaced plurality of openings extending forwardly therethrough, a spaced plurality of hollow, perforate fuel burners carried by the support structure, the fuel burners projecting forwardly from the support structure in alignment with the heat exchanger tube inlets and having rear inlets respectively communicating with the plurality of support structure openings; and
- combustion apparatus operative to sequentially (1) flow a fuel/air pre-mixture from a source thereof forwardly through the support structure openings into the interiors of the fuel burners, (2) combust the fuel/air pre-mixture received within the fuel burners to create separate, spaced apart, forwardly directed burner flames respectively aligned with and received within the heat exchanger tube inlets to create hot combustion gases within the heat exchanger tubes for heating a supply fluid flowed externally across the heat exchanger tubes, and then (3) flow cooled combustion gases outwardly from the outlets of the heat exchanger tubes.
2. The fuel-fired heating apparatus of claim 1 wherein:
- the fuel-fired heating apparatus is an air heating furnace.
3. The fuel-fired heating apparatus of claim 1 wherein:
- each of the fuel burners has a generally cone-shaped configuration with a forwardly directed apex portion.
4. The fuel-fired heating apparatus of claim 1 wherein:
- each of the fuel burners has a generally dome-shaped configuration.
5. The fuel-fired heating apparatus of claim 1 wherein:
- each of the fuel burners is of a metal mesh material.
6. The fuel-fired heating apparatus of claim 1 wherein:
- the housing has an interior flange portion, and
- the support structure is secured to the interior flange portion.
7. The fuel-fired heating apparatus of claim 1 wherein the support structure includes:
- a support plate through which the openings forwardly extend, the openings receiving rear inlet portions of the fuel burners, the support plate having front and rear sides,
- a perforate backing member positioned against the rear side of the support plate, and
- a mounting frame connected to a peripheral portion of the support plate and retaining the perforated backing member on the support plate.
8. The fuel-fired heating apparatus of claim 1 wherein the combustion apparatus includes:
- a draft inducer fan operative to draw the cooled combustion gases outwardly from the outlets of the heat exchanger tubes.
9. The fuel-fired heating apparatus of claim 1 wherein the combustion apparatus includes:
- an igniter operative to ignite one of the fuel burners, and
- flame carryover apparatus operative to spread the flame from the ignited burner to at least one unignited fuel burner.
10. The fuel-fired heating apparatus of claim 9 wherein:
- the support structure includes a support plate through which the openings forwardly extend, the openings receiving rear inlet portions of the fuel burners, and
- the flame carryover apparatus includes slots formed in the support plate and interdigitated with the openings, and a mesh material disposed in the slots, interconnecting the fuel burners, and operative to spread a flame from an ignited fuel burner to an unignited fuel burner.
11. The fuel-fired heating apparatus of claim 10 further comprising:
- a perforated diffuser plate, positioned rearwardly of the burner assembly, through the perforations of which the fuel/air pre-mixture flows before entering the support structure openings.
12. A pre-mixed fuel/air burner assembly comprising:
- a support structure having a spaced plurality of openings extending forwardly therethrough;
- a spaced plurality of hollow, perforated fuel burners having open inlet ends carried by the support structure and respectively communicated with the plurality of support structure openings to receive within the fuel burner interiors fan-created flows of pre-mixed fuel and air, and outlet ends spaced forwardly apart from the support structure; and
- combustion apparatus operative to ignite flows of pre-mixed fuel and air received within the interiors of the fuel burners to create spaced apart individual flames forwardly emanating from the fuel burners.
13. The pre-mixed fuel/air burner assembly of claim 12 wherein:
- the pre-mixed fuel/air burner assembly is configured for use in a fuel-fired air heating furnace.
14. The pre-mixed fuel/air burner assembly of claim 12 wherein:
- each of the fuel burners has a generally cone-shaped configuration with a forwardly directed apex portion.
15. The pre-mixed fuel/air burner assembly of claim 12 wherein:
- each of the fuel burners has a generally dome-shaped configuration.
16. The pre-mixed fuel/air burner assembly of claim 12 wherein:
- each of the fuel burners is of a metal mesh material.
17. The pre-mixed fuel/air burner assembly of claim 12 wherein the combustion apparatus includes:
- an igniter operative to ignite one of the fuel burners, and
- flame carryover apparatus operative to spread the flame from the ignited burner to at least one unignited fuel burner.
18. The pre-mixed fuel/air burner assembly of claim 17 wherein:
- the support structure includes a support plate through which the openings forwardly extend, the openings receiving rear inlet portions of the fuel burners, and
- the flame carryover apparatus includes slots formed in the support plate and interdigitated with the openings, and a mesh material disposed in the slots, interconnecting the fuel burners, and operative to spread a flame from an ignited fuel burner to an unignited fuel burner.
19. A pre-mixed fuel/air burner assembly comprising:
- a support plate having a spaced plurality of openings extending therethrough between front and rear sides thereof, the support plate further having slots formed therethrough, the slots being interdigitated with and intercommunicating the plurality of support plate openings;
- a spaced plurality of hollow, metal mesh fuel burners having open inlet ends respectively mounted within the plurality of support plate openings to receive fan-created flows of pre-mixed fuel and air, and outlet ends spaced forwardly apart from the support plate;
- a perforated backing member positioned against the rear side of the support plate over the support plate openings;
- a mounting frame secured to a peripheral portion of the rear side of the support plate and retaining the perforated backing member thereon;
- an igniter associated with the support plate and operative to ignite a pre-mixture of fuel and air within one of the fuel burners; and
- a mesh material disposed within the slots and intercommunicating the fuel burners, the mesh material being operative to carry the flame from an ignited fuel burner to an unignited fuel burner.
20. The pre-mixed fuel/air burner assembly of claim 19 wherein:
- the fuel burners have generally conical configurations.
21. The pre-mixed fuel/air burner assembly of claim 19 wherein:
- the fuel burners have generally dome-shaped configurations.
Type: Application
Filed: Jan 6, 2014
Publication Date: Jul 9, 2015
Applicant: Rheem Manufacturing Company (Atlanta, GA)
Inventors: Amin Akbarimonfared (Fort Smith, AR), Timothy J. Shellenberger (Tyrone, GA), Darryl J. Farley (Fort Smith, AR), Nathan T. Whalen (Alma, AR), Trent E. Thompson (Roland, OK)
Application Number: 14/148,204