Burner assembly and heat exchanger

Systems and methods are disclosed that include providing a cooking system that comprises a burner assembly and a heat exchanger, the burner assembly having a high velocity burner configured to provide the necessary high velocity, volumetric flowrate through the heat exchanger having a first fluid circuit having a plurality of compactly-arranged tubes disposed perpendicularly and interstitially to a second fluid circuit having a plurality of compactly-arranged tubes, and the burner assembly also having a low velocity burner configured to significantly reduce and/or substantially eliminate “lift off” that could result from operation of only the high velocity burner.

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

Food service equipment often includes heat generation equipment and/or heat transfer equipment to produce and/or transfer heat to a cooking medium contained in a cooking vessel for cooking consumables prior to packaging. Such heat generation equipment and/or heat transfer equipment often includes a burner configured to combust an air/fuel mixture to produce heat and a heat exchanger to transfer the heat produced by the burner to the cooking medium. Traditional food service burners and/or heat exchangers may often be inefficient at transferring heat to the cooking medium and/or require frequent monitoring and/or replacement of the cooking medium.

SUMMARY

In some embodiments of the disclosure, a burner assembly is disclosed as comprising a first burner configured to combust an air/fuel mixture at a first flowrate; a second burner configured to combust an air/fuel mixture at a second flowrate, wherein the second flowrate is lower than the first flowrate; and an igniter configured to ignite the air/fuel mixture in each of the first burner and the second burner.

In other embodiments of the disclosure, a cooking system is disclosed as comprising a burner assembly comprising: a first burner configured to combust an air/fuel mixture at a first flowrate; a second burner configured to combust an air/fuel mixture at a second flowrate, wherein the second flowrate is lower than the first flowrate; and an igniter configured to ignite the air/fuel mixture in each of the first burner and the second burner; and a heat exchanger comprising a fluid duct and configured to receive the combusted air/fuel mixture from the first burner and the second burner through the fluid duct.

DETAILED DESCRIPTION

In some cases, it may be desirable to provide a cooking system with a burner assembly having a high velocity burner to force combusted air and fuel through a heat exchanger and a low velocity burner to maintain a continuous combustion process and prevent so-called “lift off” where a flame and/or combustion process may be extinguished by a high velocity combustion process that exceeds the ignition capabilities of the burner. For example, where a heat exchanger comprises a plurality of compactly-arranged tubes comprising a plurality of fluid circuits, resistance to fluid flow through a fluid duct of the heat exchanger may be excessive, such that traditional burners would fail to pass combusted air and fuel through the heat exchanger and would suffer from “lift off” if the velocity and/or flowrate of combustion was increased. Accordingly, a cooking system is disclosed herein that comprises providing a burner assembly with a high velocity burner configured to provide the necessary high velocity flowrate through a heat exchanger having a first fluid circuit having a plurality of compactly-arranged tubes disposed perpendicularly and interstitially to a second fluid circuit having a plurality of compactly-arranged tubes and a low velocity burner configured to significantly reduce and/or substantially eliminate “lift off” that could result from operation of only the high velocity burner.

Referring now toFIGS. 1-5, various views of a burner assembly100are shown according to an embodiment of the disclosure. The burner assembly100generally comprises a body102, a manifold110, a plurality of runners112joining the body102to the manifold110, a plurality of first burners126, a plurality of second burners138, a ribbon burner146, and a plurality of deflectors122. The body102comprises a lower portion104joined to an upper portion106. In some embodiments, the lower portion104may be bolted to the upper portion106using fasteners124disposed through holes in the lower portion104and threaded into the upper portion106. In some embodiments, a gasket108may be disposed between the lower portion104and the upper portion106of the body102to prevent leakage and/or seepage of any fluid flowing within the cavity105from escaping between the lower portion104and the upper portion106. When assembled, the lower portion104and the upper portion106generally form a cavity105through which fuel and/or an air/fuel mixture may flow.

The burner assembly100also comprises a manifold110configured to deliver the fuel and/or the air/fuel mixture into the cavity105through a plurality of parallel runners112. Each runner112comprises a lower threaded portion114, an upper threaded portion116, and a butt joint118that joins the lower threaded portion114to the upper threaded portion116. In some embodiments, it will be appreciated that each runner112may be a solid piece and comprise the lower threaded portion114and the upper threaded portion116joined by the butt joint118. The lower threaded portion114may generally be threaded into and extend into an inner opening of the manifold110, such that fuel and/or an air/fuel mixture may flow from an internal volume of the manifold110through an internal volume of the lower threaded portion114and into an internal volume of the butt joint118. The upper threaded portion116may generally be threaded into the lower portion104of the body102and extend into the cavity105of the body102. Accordingly, an internal volume of the upper threaded portion116may receive fuel and/or an air/fuel mixture from the internal volume of the butt joint118. It will be appreciated that each runner112thus comprises a fluid flow path that extends through internal volumes of the lower threaded portion114, the butt joint118, and the upper threaded portion116. Furthermore, the upper threaded portion116comprises a plurality of fuel delivery holes120that may distribute the fuel and/or the air/fuel mixture received from the manifold110evenly throughout the cavity105. Additionally, in some embodiments, an upper distal end of the upper threaded portion116may be closed and/or substantially abut a substantially flat surface of the upper portion106of the body102so that the fuel and/or the air/fuel mixture that passes through the runner112only escapes the upper threaded portion116through the fuel delivery holes120.

The burner assembly100comprises a plurality of first burners126arranged adjacently along a length of the upper portion106of burner assembly100. Additionally, the plurality of first burners126are arranged along a centerline of the upper portion106of the body102, such that the centerline of the body102intersects a center axis of each first burner126. Each first burner126comprises a cylindrically-shaped first bore128configured to receive the fuel and/or the air/fuel mixture from the cavity105. The first bore128also comprises a plurality of holes132disposed about the first bore128that are configured to allow the fuel and/or the air/fuel mixture to flow from the first bore128to a combustion chamber134that is formed by a cylindrically-shaped third bore130. Each first burner126also comprises a cylindrically-shaped second bore129that is axially aligned with and disposed downstream from the first bore128with respect to the flow of the fuel and/or the air/fuel mixture through the burner assembly100and that comprises a diameter that is smaller than the diameter of the first bore128. The second bore129may also receive the fuel and/or the air/fuel mixture from the first bore128. In some embodiments, the smaller diameter of the second bore129may be sized to control a pressure drop through the second bore129and/or the plurality of holes132disposed about the first bore128.

Accordingly, the first burner126may define a first flowpath131from the cavity105through the first bore128and the second bore129into the combustion chamber134and further define a plurality of second flowpaths133from the cavity105through the first bore128, through the plurality of holes132, and into the combustion chamber134. Furthermore, as will be discussed herein in further detail, to ignite the fuel and/or the air/fuel mixture in the first burner126, each first burner126also comprises a groove136disposed in the third bore130that forms the cylindrically-shaped combustion chamber134on each of an opposing left side and right side of the combustion chamber134so that fuel through the first flowpath131and the plurality of second flowpaths133of the first burner126may be ignited by the ribbon burner146. In some embodiments, the flowrate and/or volume of the fuel and/or the air/fuel mixture through the first flowpath131of the first burner126may be greater than the flowrate and/or volume of the fuel and/or the air/fuel mixture through the plurality of second flowpaths133through the first burner126. However, in other embodiments, the flowrate and/or volume of the fuel and/or the air/fuel mixture through the first flowpath131of the first burner126may be equal to or less than the flowrate and/or volume of the fuel and/or the air/fuel mixture through the plurality of second flowpaths133through the first burner126.

The burner assembly100also comprises a plurality of second burners138disposed on each of a left side and a right side of the upper portion106of the body102of burner assembly100. Each second burner138may generally be configured as a low flow-rate ribbon burner146that comprises a plurality of feeder holes140, a cavity142, and a plurality of upper holes144. The feeder holes140are configured to receive the fuel and/or the air/fuel mixture from the cavity105and allow the fuel and/or the air/fuel mixture to flow into a cavity142that houses the ribbon burner146. The second burner138also comprises a plurality of upper holes144that are disposed on the left and right sides of the cavity142and the ribbon burner146. The upper holes144receive fuel and/or the air/fuel mixture from the cavity142. Accordingly, the second burner138may define a first flowpath141from the cavity105through a plurality of feeder holes140, into the cavity142, and through a plurality of upper holes144. Furthermore, as will be discussed herein in further detail, the fuel and/or the air/fuel mixture flowing through the upper holes144may be ignited by the ribbon burner146.

Additionally, the ribbon burner146comprises a plurality of small perforations148that may also allow fuel and/or the air/fuel mixture to pass through a plurality of second flowpaths143from the cavity142through the perforations148, where they may be ignited by the ribbon burner146. In some embodiments, the flowrate and/or volume of the fuel and/or the air/fuel mixture through the first flowpath141of the second burner138may be greater than the flowrate and/or volume of the fuel and/or the air/fuel mixture through the plurality of second flowpaths143through the second burner138. However, in other embodiments, the flowrate and/or volume of the fuel and/or the air/fuel mixture through the first flowpath141of the second burner138may be equal to or less than the flowrate and/or volume of the fuel and/or the air/fuel mixture through the plurality of second flowpaths143through the second burner138. Additionally, in some embodiments, the combined flowrate and/or volume of the fuel and/or the air/fuel mixture through a first burner126may be greater than the flowrate and/or volume of the fuel and/or the air/fuel mixture through a second burner138. However, in alternative embodiments, the combined flowrate and/or volume of the fuel and/or the air/fuel mixture through a first burner126may be equal to or less than the flowrate and/or volume of the fuel and/or the air/fuel mixture through a second burner138.

In some embodiments, the burner assembly100may comprise one or more infrared burners. Accordingly, the first burner126, the second burner138, and/or the ribbon burner146may be configured as an infrared burner. Accordingly, first burner126, the second burner138, and/or the ribbon burner146may comprise additional components, including but not limited to, ceramic components and/or other components necessary to configure and/or operate the first burner126, the second burner138, and/or the ribbon burner146as an infrared burner. However, in some embodiments, the first burner126, the second burner138, and/or the ribbon burner146may alternatively be configured as any other suitable burner.

In operation, the burner assembly100is configured to combust fuel and/or an air/fuel mixture through a plurality of first burners126and a plurality of second burners138. In some embodiments, the burner assembly100may also comprise a separate igniter and/or a plurality of igniters configured to ignite the air/fuel mixture in each of the first burners126and the second burners138. In this embodiment, the combined flowrate and/or volume of the fuel and/or air/fuel mixture through the first burners126is greater than the flowrate and/or volume of the fuel and/or the air/fuel mixture through the plurality of second burners138. Accordingly, the velocity of the combusted fuel and/or the combusted air/fuel mixture through the first burners126is higher than the velocity of the combusted fuel and/or the combusted air/fuel mixture through the second burners138.

Because the velocity of the combusted fuel and/or combusted air/fuel mixture through the first burners126exits the first burners126at such a high velocity, traditional burners may experience so-called “lift off” where the flame is extinguished due to the high velocity. As such, the lower velocity of the combusted fuel and/or the combusted air/fuel mixture exiting the second burners138may prevent this “lift off” by continuously burning fuel at a lower flowrate and/or delivering a combusted air/fuel mixture at the lower velocity. Additionally, the burner assembly100also comprises a deflector122on each of a left side and a right side of the upper portion106of the body102of burner assembly100that is secured to the upper portion106of the body102by a plurality of fasteners124. The deflectors122may be angled towards a center of the upper portion106and extend over the second burners138in order to deflect the combusted air/fuel mixture exiting the second burners138towards the combusted air/fuel mixture exiting the first burners126. Accordingly, the deflectors122may also aid in preventing “lift off” by directing the lower velocity combusted air/fuel mixture exiting the second burners138towards the higher velocity combusted air/fuel mixture exiting the first burners126.

Referring now toFIGS. 6-8, an oblique side view, an oblique cross-sectional side view, and an oblique end view of a heat exchanger200are shown, respectively, according to an embodiment of the disclosure. The heat exchanger200comprises a first fluid circuit201having a first inlet202, a plurality of top headers204, a plurality of downward tubes206, a plurality of bottom headers208, a plurality of upward tubes210, and a first outlet212. The first inlet202is connected in fluid communication with a first top header204′ and is configured to receive a fluid therethrough and allow the fluid to enter the first top header204′. The first top header204′ is connected in fluid communication with a first set of downward tubes206, which is connected in fluid communication with a bottom header208. Fluid from the first top header204′ may flow through the first set of downward tubes206into a bottom header208. The bottom header208may also be connected in fluid communication with a set of upward tubes210that may carry fluid from the bottom header208through the upward tubes210and into another top header204. Accordingly, this pattern may continue along the length of the heat exchanger200, such that each top header204transfers fluid through a set of downward tubes206into a bottom header208and subsequently from the bottom header208through a set of upward tubes210into an adjacently downstream located top header204.

Furthermore, it will be appreciated that downward tubes206may be associated with carrying a fluid from a top header204in a downward direction towards and into a bottom header208, and upward tubes210may be associated with carrying a fluid from a bottom header208in an upward direction towards and into a top header204. This pattern may continue along the length of the heat exchanger200until a last set of downward tubes206carries fluid through into a final bottom header208′ and out of the first outlet212. Accordingly, the first fluid circuit201comprises passing fluid from the first inlet202into the first top header204′ through a repetitive serpentine series of downward tubes206, a bottom header208, a set of upward tubes210, and a top header204until passing through a final set of downward tubes206into the final bottom header208′ and exiting the heat exchanger200through the first outlet212. Furthermore, in other embodiments, it will be appreciated that the first inlet202and/or the first outlet212may alternatively be disposed both in a top header204, both in a bottom header208, or in opposing top and bottom headers204,208.

The heat exchanger200also comprises a second fluid circuit213having a second inlet214, a plurality of left headers216, a plurality of rightward tubes218, a plurality of right headers220, a plurality of leftward tubes222, and a second outlet224. The rightward tubes218and the leftward tubes222may be oriented substantially perpendicular to the downward tubes206and the upward tubes210of the first fluid circuit201. The second inlet214is connected in fluid communication with a first left header216′ and is configured to receive a fluid therethrough and allow the fluid to enter the first left header216′. The first left header216′ is connected in fluid communication with a first set of rightward tubes218, which is connected in fluid communication with a right header220. Fluid from the first left header216′ may flow through the first set of rightward tubes218into a right header220. The right header220may also be connected in fluid communication with a set of leftward tubes222that may carry fluid from the right header220through the leftward tubes222and into another left header216. Accordingly, this pattern may continue along the length of the heat exchanger200, such that each left header216transfers fluid through a set of rightward tubes218into a right header220and subsequently from the right header220through a set of leftward tubes222into an adjacently downstream located left header216.

Furthermore, it will be appreciated that rightward tubes218may be associated with carrying a fluid from a left header216in a rightward direction towards and into a right header220, and leftward tubes222may be associated with carrying a fluid from a right header220in a leftward direction towards and into a left header216. This pattern may continue along the length of the heat exchanger200until a last set of rightward tubes218carries fluid through into a final right header220′ and out of the second outlet224. Accordingly, the second fluid circuit213comprises passing fluid from the second inlet214into the first left header216′ through a repetitive serpentine series of a set of rightward tubes218, a right header220, a set of leftward tubes222, and a left header216until passing through a final set of rightward tubes218into the final right header220′ and exiting the heat exchanger200through the second outlet224. Furthermore, in other embodiments, it will be appreciated that the second inlet214and/or the second outlet224may alternatively be disposed both in a left header216, both in a right header220, or in opposing left and right headers216,220. Additionally, it will be appreciated that in some embodiments, the heat exchanger200may comprise only one of the first fluid circuit201and the second fluid circuit213.

Furthermore, it will be appreciated that the first fluid circuit201and the second fluid circuit213may comprise different lengths. Accordingly, the first inlet202and/or the first outlet212may be disposed in any of the top headers204or bottom headers208, and the second inlet214and/or the second outlet224may be disposed in any of the left headers216and the right headers220to vary the length of the fluid circuits201,213, respectively. By altering the length of the fluid circuits201,213, the heat exchanger200may be configured to maintain a temperature gradient, reduce a pressure drop, and/or otherwise control the temperature and/or pressure of the fluid though each of the fluid circuits201,213.

The tubes206,210,218,222of the heat exchanger200may generally be arranged to provide a compact, highly resistive flowpath through the fluid duct228. In order to effectively and/or evenly distribute the heat produced by burner assembly100through the tubes206,210,218,222, sets and/or rows of tubes206,210may be interstitially and/or alternatively spaced with sets and/or rows of tubes218,222. In the shown embodiment, two rows of downward tubes206, two rows of rightward tubes218, two rows of upward tubes210, and two rows of leftward tubes222are interstitially and/or alternatively spaced, respectively, along the length of the heat exchanger200. However, in alternative embodiments, a single row of tubes206,210,218,222may be interstitially and/or alternatively spaced, respectively, along the length of the heat exchanger200. In other embodiments, however, heat exchanger200may comprise any number of rows of tubes206,210,218,222interstitially and/or alternatively spaced along the length of the heat exchanger200. For example, heat exchanger200may comprise three rows of downward tubes206, two rows of rightward tubes218, three rows of upward tubes210, and two rows of leftward tubes222may be interstitially and/or alternatively spaced. Accordingly, it will be appreciated that the number of rows of tubes206,210,218,222interstitially and/or alternatively spaced may vary, so long as at least one row of vertically-oriented tubes206,210is disposed adjacently with at least one row of horizontally-oriented tubes218,222along the length of the heat exchanger200.

The heat exchanger200also comprises a plurality of mounting holes226disposed through a mounting flange227that is disposed at the distal end of the heat exchanger200located closest to the first inlet202and the second inlet214. The mounting holes226may generally be configured to mount the heat exchanger200to the burner assembly100ofFIGS. 1-5. In some embodiments, the heat exchanger200may be secured to the burner assembly100via fasteners124. However, in other embodiments, the heat exchanger200may be secured to the burner assembly100through an alternative mechanical interface. The heat exchanger200is secured to the burner assembly100so that combusted fuel and/or combusted air/fuel mixture is forced through a plurality of inner walls of the heat exchanger200that form a fluid duct228through the heat exchanger200. Accordingly, heat from the combusted fuel and/or the combusted air/fuel mixture may be absorbed by a fluid flowing through the tubes206,210,218,222of the heat exchanger200. The heated fluid may exit the heat exchanger200through the first outlet212and the second outlet224of the first fluid circuit201and the second fluid circuit213, respectively, and therefore be used to heat and/or cook consumable products (i.e. chips, crackers, frozen foods).

In operation, the configuration of tubes206,210,218,222provides a compact, highly resistive flowpath through the fluid duct228. Accordingly, to force combusted fuel and/or combusted air/fuel mixture through the fluid duct228requires high velocity. Accordingly, the velocity of the combusted fuel and/or the combusted air/fuel mixture through the first burners126of the burner assembly100is high enough to provide the requisite velocity needed to overcome the resistance to flow through the heat exchanger200. Furthermore, the lower velocity of the combusted fuel and/or the combusted air/fuel mixture through the second burners138of the burner assembly100prevents “lift off” so that the combustion process remains constant through the burner assembly100.

Referring now toFIG. 9, a schematic of a cooking system300is shown according to an embodiment of the disclosure. Cooking system300generally comprises at least one burner assembly100, at least one heat exchanger200, at least one cooking vessel302(e.g. a fryer), at least one oil input line303, and at least one oil output line304. As previously disclosed, the burner assembly100may be mounted to at least one heat exchanger200. However, in this embodiment, the burner assembly100may be mounted to a plurality of heat exchangers200. Furthermore, while not shown, in some embodiments, multiple burner assemblies100may be mounted to multiple heat exchangers200in the cooking system300. The burner assembly100is configured to provide a high velocity flow of combusted fuel and/or combusted air/fuel mixture through the fluid duct228of the heat exchangers200.

Fluid, such as a cooking fluid (e.g. oil) may be pumped into the first inlet202and/or the second inlet214of the heat exchangers200through a plurality of oil input lines303, each oil input line303being associated with a respective inlet202,214. Fluid may enter the oil input lines303from a reservoir and/or may be circulated through the heat exchangers200from the cooking vessel302. The fluid may be pumped and/or passed through the tubes206,210,218,222of the heat exchangers200. Heat produced from the combustion of fuel and/or an air/fuel mixture in the burner assembly100may be transferred to the fluid flowing through the tubes206,210,218,222of the heat exchangers200. The heated fluid may exit the heat exchanger200through the first outlet212and the second outlet224and be carried into the cooking vessel302through a plurality of oil output lines304, each oil output line304being associated with a respective outlet212,224. In some embodiments, the heated fluid may be carried into the cooking vessel302at different locations to maintain a proper temperature, temperature gradient, and/or temperature profile within the cooking vessel302. As stated, in some embodiments, fluid from the cooking vessel302may be recirculated through the oil input lines303and reheated within the heat exchangers200. Furthermore, it will be appreciated while burner assembly100is disclosed in the context of food service equipment (e.g. fryer, boiler), the burner assembly100may be used for any application or industry that requires a fluid to be heated rapidly, consistently, and efficiently.

Referring now toFIG. 10, a schematic of a cooking system400is shown according to another embodiment of the disclosure. Cooking system400may be substantially similar to cooking system300ofFIG. 9. However, cooking system400comprises a plurality of burner assemblies100, a plurality of heat exchangers200, at least one cooking vessel302(i.e., a fryer), at least one oil input line303per heat exchanger200, and at least one oil output line304per heat exchanger200. As previously disclosed, each burner assembly100may be associated with at least one heat exchanger200. However, in this embodiment, each burner assembly100may be mounted to a single heat exchanger200. Each burner assembly100is configured to provide a high velocity flow of combusted fuel and/or combusted air/fuel mixture through the fluid duct228of the associated heat exchanger200.

Fluid, such as a cooking fluid (e.g. oil) may be pumped into the first inlet202and/or the second inlet214of the heat exchanger200through a plurality of oil input lines303, each oil input line303being associated with a respective inlet202,214. Fluid may enter the oil input lines303from a reservoir and/or may be circulated through the heat exchangers200from the cooking vessel302. The fluid may be pumped and/or passed through the tubes206,210,218,222of the heat exchanger200. Heat produced from the combustion of fuel and/or an air/fuel mixture in the burner assemblies100may be transferred to the fluid flowing through the tubes206,210,218,222of each respective heat exchanger200. The heated fluid may exit the heat exchangers200through the first outlet212and the second outlet224of each heat exchanger200and be carried into the cooking vessel302through a plurality of oil output lines304, each oil output line304being associated with a respective outlet212,224.

In some embodiments, the heated fluid may be carried into the cooking vessel302at different locations to maintain a proper temperature, temperature gradient, and/or temperature profile within the cooking vessel302. Furthermore, it will be appreciated that each burner assembly100may be individually controlled by a burner controller (not pictured). As such, in some embodiments, each burner assembly100may be operated at substantially similar temperatures. However, in other embodiments, each burner assembly100may be operated at different temperatures to maintain a temperature gradient across the cooking vessel302and/or to control a cooking process requiring different temperatures. Still further, while multiple burner assemblies100and multiple heat exchangers200are pictured, in some embodiments, a single burner assembly100may be associated with a single heat exchanger200to provide heated fluid to the cooking vessel302. As stated, in some embodiments, fluid from the cooking vessel302may be recirculated through the oil input lines303and reheated within the heat exchangers200. Furthermore, it will be appreciated while burner assembly100is disclosed in the context of food service equipment (e.g. fryer, boiler), the burner assembly100may be used for any application or industry that requires a fluid to be heated rapidly, consistently, and efficiently.