Patent Application
20180209643
The presently disclosed embodiments generally relate to combustion systems and, more particularly, to burner enclosures for combustion systems.
In combustion systems, such as burner assemblies for ultra low NOx applications generally found in HVAC/R units, a mixture of fuel and air is ignited in an enclosure to form a stable flame attached to a burner surface, such as a burner mesh. Generally, ignition may result in a sudden increase in pressure within the enclosure. The sudden pressure increase may decrease flame stability within the enclosure, including causing flame blow off or the alternating detachment and attachment of the flame to the burner surface. Such action may also generate excessive noise and/or vibrations within the assembly. Further, as the air-fuel mixture is introduced into the enclosure, the mixture may not become sufficiently mixed to maintain acceptable flame stability and NOx levels.
Therefore, there exists a need in the art for a burner enclosure that improves combustion stability and reduces the likelihood of flame blow off and/or noise generation. Further, there exists a need in the art for a burner enclosure that improves mixing of the air-fuel mixture.
In accordance with an embodiment of the present disclosure, a burner enclosure for a combustion system is provided. The burner enclosure includes a first enclosure portion configured to receive air and fuel, a second enclosure portion including an outlet, a partition disposed between the first enclosure portion and the second enclosure portion, and a passage connecting the first enclosure portion to the second enclosure portion such that the air and fuel may flow from the first enclosure portion to the second enclosure portion.
The burner enclosure may further include an ignition source disposed adjacent to the outlet. The first enclosure portion and the passage may be configured to at least partially mix the air and fuel. The passage may be sized to minimize ignition blow-off. The passage may be sized to minimize noise generation. The passage may be spaced from the partition. The passage may be formed at least partially by the partition.
In accordance with an embodiment of the present disclosure, a burner assembly for a combustion system is provided. The burner assembly includes a heat exchanger cavity, a burner head disposed in the heat exchanger cavity, and a burner enclosure operably coupled to the heat exchanger cavity, the burner enclosure including a first enclosure portion configured to receive air and fuel, a second enclosure portion including an outlet, a partition disposed between the first enclosure and the second enclosure, and a passage connecting the first enclosure portion to the second enclosure portion such that the air and fuel may flow from the first enclosure portion to the second enclosure portion.
The burner assembly may further include an ignition source disposed within the heat exchanger cavity and adjacent to the outlet. The first enclosure portion and the passage may be configured to at least partially mix the air and fuel. The passage may be sized to minimize ignition blow-off. The passage may be sized to minimize noise generation. The passage may be spaced from the partition. The passage may be formed at least partially by the partition.
The embodiments and other features, advantages and disclosures contained herein, and the manner of attaining them, will become apparent and the present disclosure will be better understood by reference to the following description of various exemplary embodiments of the present disclosure taken in conjunction with the accompanying drawings, wherein:
For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of this disclosure is thereby intended.
Referring now to
The enclosure 12 further includes a partition 26 disposed between the first enclosure portion 18 and the second enclosure portion 22. The partition 26 is configured to introduce an impedance over a Helmholtz Resonance generated inside the burner assembly 10. The resonance is the main source of undesired tonal noise of the burner assembly 10. The partition 26 reduces and/or eliminates this tonal noise. In other words, the partition 26 is a shield against excessive noise and vibration generated upon ignition of the air-fuel mixture 38 and/or during other operations of the burner assembly 10. The partition 26 includes a first surface 28 facing the first enclosure portion 18 and a second surface 30 facing the second enclosure portion 22 in the embodiment illustrated in
The enclosure 12 further includes a passage 32 connecting the first enclosure portion 18 to the second enclosure portion 22. The passage 32 is positioned, sized, shaped, and/or generally configured to at least partially mix the air and fuel 20. As illustrated in
Generally, upon ignition of the air-fuel mixture 38, a significant and sudden increase in pressure may occur in the second enclosure portion 22 to induce the flame to travel downstream and detach from the burner mesh 50. With no passage 32, or an excessively small passage 32, there will likely be a flame blow-off condition, which generates an undesired rumbling noise in the burner assembly 10. Therefore, the passage 32 is sized at or above a threshold dimension to minimize ignition or flame blow-off in an embodiment. In other words, the passage 32 is positioned, sized, shaped, and/or generally configured to act as a safety valve at the time of ignition to maintain combustion stability.
However, if the passage 32 is too large, the enclosure 12 and/or the partition 26 will not properly shield against excessive noise and vibration generated upon ignition of the air-fuel mixture 38 or during other operations of the burner assembly 10. As such, the passage 32 is sized at or below a threshold dimension to dampen or minimize transmission of noise and/or vibrations generated by ignition or other operations. One of ordinary skill in the art will recognize that the size, shape, and/or configuration of the passage 32, the partition 26, and/or the first and second enclosure portions 18, 22 will significantly affect the threshold dimension for the passage 32.
In particular embodiments, the passage 32 has a cross sectional area falling within a range between about 0.70 square inches and about 7.00 square inches. The passage 32 has a cross sectional area falling within a range between about 0.20 square inches and about 20.00 square inches in further embodiments. The ratio of the cross sectional area of the passage 32 relative to an area of the partition 26 falls within a range of between about 0.02 and about 0.35 in particular embodiments. The ratio of the cross sectional area of the passage 32 relative to the area of the partition 26 falls within a range of between about 0.01 and about 1.00 in further embodiments. The ratio of the cross sectional area of the passage 32 relative to the area of the partition 26 is less than about 0.01 in an embodiment and greater than about 1.00 in an embodiment.
The passage 32 of the embodiment illustrated in
Referring now to
One will appreciate that the embodiments described in the present disclosure provide the burner assembly 10 having the burner enclosure 12 that improve operation of a combustion system. The passage 32 is positioned, sized, shaped, and or configured to enhance mixing of the air and fuel 20 as the mixture flows between the first enclosure portion 18 and the second enclosure portion 22. Such mixture enhancement improves combustion stability and reduces NOx levels. Further, the passage 32 and partition 26 of the burner enclosure 12 reduce the likelihood of flame blow-off during the rapid pressure increase of ignition. Finally, the passage 32 and partition 26 reduce the transmission of noise and/or vibration originating from the second enclosure portion 22. The structures and functions described herein improve the efficiency and reliability of a combustion system and improve the comfort of the user of such a system.
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.
The present application is a nonprovisional patent application, and claims the priority benefit of U.S. Application Ser. No. 62/448,753, filed Jan. 20, 2017, the text and drawings of which are hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62448753 | Jan 2017 | US |
