This disclosure relates to a burner assembly for a furnace. More specifically, the disclosure relates to a baffle for use in a burner assembly used in a pre-mix combustion system in a furnace. During operation of the furnace, it is possible that an undesirable combustion tone will occur in the burner assembly that is unpleasant to those in the vicinity of the furnace. Therefore, there is a need to reduce or eliminate the production combustion tones during operation of a furnace.
In one exemplary embodiment, a burner assembly includes a burner box that defines an enclosure that has a burner plate opening. A mixing tube is in fluid communication with the burner box through a mixing tube opening that extends through the burner box. A baffle creates an enclosure that at least partially separates the mixing tube opening from the burner plate opening.
In a further embodiment of the above, the burner box includes a pair of side walls, a pair of end walls, and a back wall facing the burner plate opening. The mixing tube opening extends through one of the pair of side walls, the pair of end walls, and the back wall.
In a further embodiment of any of the above, the baffle at least partially defines a premix flow path with at least one of the pair of side walls and the pair of end walls.
In a further embodiment of any of the above, the baffle at least partially defines the premix flow path with the back wall.
In a further embodiment of any of the above, the baffle includes a portion at least partially following a profile of the mixing tube opening in the burner box.
In a further embodiment of any of the above, the portion at least partially following a profile of the mixing tube opening is a curved portion.
In a further embodiment of any of the above, the baffle includes at least one wing that extends from the curved portion.
In a further embodiment of any of the above, at least one tab extends transverse from at least one wing.
In a further embodiment of any of the above, at least one flange extends from opposite sides of at least one wing and at least one tab.
In a further embodiment of any of the above, the baffle engages each of one of the pair of end walls or side walls and is spaced from each of the other of the pair of end walls or the pair of side walls.
In a further embodiment of any of the above, a burner plate is located in the burner plate opening.
In a further embodiment of any of the above, the burner plate includes a pair of burner plate side walls, a pair of burner plate end walls, and a burner plate back wall that all extend into the burner box.
In a further embodiment of any of the above, the pair of burner plate side walls and the pair of burner plate end walls include perforations. The back wall includes a plurality of protruding perforated disks.
In another exemplary embodiment, a furnace includes a heater exchanger. A burner assembly in thermal communication includes a burner box that defines an enclosure that has a burner plate opening. A mixing tube is in fluid communication with the burner box through a mixing tube opening and extends through the burner box. A baffle creates an enclosure at least partially separating the mixing tube opening from the burner plate opening. A blower is configured to direct air across the heat exchanger.
In a further embodiment of any of the above, the burner box includes a pair of side walls, a pair of end walls, and a back wall facing the burner plate opening. The mixing tube opening extends through one of the pair of side walls, the pair of end walls, and the back wall.
In a further embodiment of any of the above, the baffle at least partially defines a premix flow path with at least one of the pair of side walls and the pair of end walls.
In a further embodiment of any of the above, the baffle at least partially defines the premix flow path with the back wall.
In a further embodiment of any of the above, the baffle engages each of one of the pair of end walls or side walls and is spaced from each of the other of the pair of end walls or the pair of side walls.
In a further embodiment of any of the above, a burner plate is located in the burner plate opening. The burner plate includes a pair of burner plate side walls, a pair of burner plate end walls, and a burner plate back wall that all extend into the burner box.
In another exemplary embodiment, a method of reducing noise in a burner assembly includes the steps of positioning an air fuel mixing tube relative to a mixing tube opening in the burner box to create at least a portion of a Helmholtz Resonator. A baffle is located within the burner box to create an enclosure at least partially separating the mixing tube opening from a burner plate opening in the burner box. The position of the baffle is varied within the burner box to vary a length of an enclosure at least partially defined by the burner box and a back wall of the burner box to extend the Helmholtz Resonator and vary a resonant frequency.
In order to extract the heat, an indoor blower assembly 22 may be provided to create a significant air flow across the heat exchanger cells 14. As the air circulates across the cells 14, it is heated and can then be directed to a space to be heated, such as a home or commercial building for example, by way of appropriate ductwork as indicated by arrow 23. The furnace 10 may also include a return 24 to enable air from the space to be heated to be recirculated and/or fresh air to be introduced for flow across the heat exchanger cells 14.
In the illustrated example, the mixing tube 34 receives a supply of fuel and air from a fuel and air source, respectively. The fuel enters the mixing tube 34 through an inlet 40 to a fuel inlet tube 38 in fluid communication with the fuel source and the air enters to mixing tube 34 through an air inlet 42 that surrounds the fuel inlet tube 38. The mixing tube 34 also includes a mixing plate 35 that increases turbulence in the air entering the inlet 42 to encourage mixing of the air and fuel prior to an elbow 36 in the mixing tube 34 changing a direction of flow through the mixing tube 34 and into the burner box 32. The mixing tube 34 also forms at least a portion of a Helmholtz Resonator, which contributes to establishing a resonant frequency and an impedance relative to the burner assembly 30.
As the air and fuel mixture enters the burner box 32 through a mixing tube opening 46 in the burner box 32, the mixture of air and fuel generally follows the flow path 44 through the burner box 32 towards the burner distribution plate 72. The burner box 32 includes a back wall 48, a pair of opposite end walls 50, and a pair of opposite side walls 52 that at least partially define an opening opposite the back wall 48 for accepting the burner distribution plate 72. The opening is surrounded by a flange 54 having a plurality of attachment openings 56. The mixing tube opening 46 could be located in any of the back wall 48, pair of end walls 50, or pair of side walls 52.
A baffle 62 at least partially separates the incoming air-fuel mixture through the mixing tube 34 from the burner distribution plate 72. In the illustrated example, the burner box 32 and the baffle 62 at least partially define an enclosure that separates the mixing tube opening 46 from the burner distribution plate 72 by having the air-fuel mixture follow the flow path 44 instead of being directed to the burner distribution plate 72.
In the illustrated example shown in
As shown in
The burner distribution plate 72 includes perforated side walls 78 and perforated end walls 80 that surround a partially perforated back wall 82. In the illustrated example, the back wall 82 includes multiple perforated discs 84 that protrude from the back wall 82 of the burner distribution plate 72. As shown in
One way to reduce the combustion tone from the burner assembly 30 is to change the upstream impedance in relation to the downstream impedance. In particular, it is desirable to achieve an upstream impedance that is larger than a downstream impedance in the furnace 10 to reduce or eliminate the presence of combustion tone in the burner assembly 30.
Increasing a length of the Helmholtz Resonator will increase the upstream impedance of the furnace 10 and reduce combustion tone. As discussed above, the mixing tube 34 functions as a portion of the Helmholtz Resonator and the portion of the burner box 32 enclosed by the baffle 62 separating the mixing tube opening 46 from the burner distribution plate 72 further extends the length of the Helmholtz Resonator. Varying a position of the baffle 62 within the burner box 32 varies of the length and/or volume of the premix flow path 44 which reduces the resonant frequency and increases the upstream impedance of the furnace 10.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.
This application claims priority to U.S. Provisional Application No. 62/737,476, which was filed on Sep. 27, 2018 and is incorporated herein by reference.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/US2019/033949 | 5/24/2019 | WO | 00 |
Number | Date | Country | |
---|---|---|---|
62737476 | Sep 2018 | US |