BAFFLE AND ASSOCIATED FRYER HEAT EXCHANGE SYSTEM AND FRYER

A fryer includes a fryer vat and a heating system with at least one heat exchange tube a burner end, an opposite end, and an internal passage from the burner end to the opposite end. A baffle is located within the internal passage for enhancing heat transfer from combustion gases to the heat exchange tube. The baffle has an axial length from a burner facing end to a discharge facing end. The baffle includes a plurality baffle panels that are interconnected and sequentially arranged along the axial length, with each baffle panel extending at least partially across the internal passage of the heat exchange tube. At least one baffle panel includes multiple sets of interconnected openings, wherein the openings of each set are interconnected with each other by one or more panel through slits so as to facilitate thermal expansion.

TECHNICAL FIELD

The present invention relates generally to heat-exchange systems used in deep-fat fryers and, more particularly, to a deep-fat fryer baffle heat exchange system.

BACKGROUND

A typical deep-fat fryer includes a fryer vat containing a heated bath of cooking oil. The cooking oil vat is adapted to receive baskets of food products such that the food products will be immersed within and cooked by the heated cooking oil. Such fryers include a heat exchanger, which often takes the form of one or more in vat or through vat heat exchange tubes through which combusted gases pass, thereby delivering heat to the oil through the tube walls. Baffles may be incorporated into the heat exchange tubes to cause a turbulent combustion gas flow that more effectively transfers heat from the combustion gases to the tube walls, and thereby to the oil surrounding the heat exchange tubes. Such baffles are, however, subject to failure due to the extreme heat conditions within the heat exchange tubes, and such failures can reduce fryer efficiency.

It would be desirable to provide a fryer and associated heat exchange tube and baffle system that effectively and efficiently heats oil in the fryer vat while reducing the likelihood of baffle failure.

SUMMARY

In one aspect, a fryer includes a fryer vat defining a volume for receiving oil to be heated for cooking, and a heating system for heating oil in the volume. The heating system includes at least one gaseous fuel burner associated with at least one heat exchange tube, the heat exchange tube passing through the volume such that an external surface of the heat exchange tube will be in contact with oil in the volume, the heat exchange tube defining an internal passage, from a burner end of the heat exchange tube to a discharge end of the heat exchange tube, through which heated combustion gases of the gaseous fuel burner can pass, and a baffle within the internal passage for enhancing heat transfer from the combustion gases to the heat exchange tube. The baffle includes a plurality baffle panels that are interconnected and sequentially arranged along an axial length of the baffle, each baffle panel extending at least partially across the internal passage of the heat exchange tube, each baffle panel including a plurality of openings therethrough. A first baffle panel, of the plurality of baffle panels, includes multiple sets of interconnected openings, wherein the openings of each set are interconnected with each other by one or more through slits formed in the first baffle panel so as to facilitate thermal expansion of the first baffle panel, wherein the first baffle panel is located closer to the burner end of the heat exchange tube than any other baffle panels of the baffle.

In another aspect, a fryer includes a fryer vat defining a volume for receiving oil to be heated for cooking, and a heating system for heating oil in the volume. The heating system includes a heat exchange tube passing through the volume, the heat exchange tube having a burner end, an opposite end, and an internal passage from the burner end to the opposite end, a baffle within the internal passage for enhancing heat transfer from combustion gases to the heat exchange tube. The baffle has an axial length from a burner facing end to a discharge facing end, wherein the baffle comprises a plurality baffle panels that are interconnected and sequentially arranged along the axial length, each baffle panel extending at least partially across the internal passage of the heat exchange tube. Each of at least a first baffle panel and a second baffle panel, of the plurality of baffle panels, includes multiple sets of interconnected openings, wherein the openings of each set are interconnected with each other by one or more panel through slits so as to facilitate thermal expansion, wherein the first baffle panel and the second baffle panel are located at the burner facing end of the baffle.

DETAILED DESCRIPTION

Referring toFIGS.1-4, a fryer10includes a housing12that supports an open-top vat14having front, rear, left, right and bottom side wall portions. Legs13support the housing and a front shelf area15is provided. The vat14walls may, for example, be formed of stainless steel or aluminum sheet metal that is formed and welded. The volume of the vat may vary widely, but typically holds about 30 to 90 pounds of oil. An access door16and handle18at the front of the fryer moves between open and closed positions to permit access to internal components, including the front side of the vat and portions of a heating system20associated with the fryer vat for heating oil within the fryer vat.

The fryer housing structure to which the vat is attached may include edge portions extending upward from the right and left sides of the vat, a front portion15extending laterally forward of the front of the vat to an upwardly extending front edge portion, and a back portion including an upwardly extending rear wall34formed by part of the chimney shell32. Here, the rear wall34extends upward to a height well above the height of the left, right and front edge portions. Additional housing structure and/or support frame structure may be associated with the bottom portion of the fryer vat as well.

The oil heating system20includes one or more (here six, per the front elevation ofFIG.2) heat exchange tubes22, each with an associated gaseous fuel burner24(shown schematically inFIG.3) at a burner end of the tube. The heat exchange tubes22extend from a front side of the fryer vat (here, the burner end of the tubes) to a read side of the fryer vat (here the discharge end of the tubes), and may be integrated with the fryer vat as a unit, such as where a front edge of each heat exchange tube is welded to the front wall of the fryer vat and a rear edge of each heat exchange tube is welded to the rear wall of the fryer vat. The heat exchange tubes22are immersed in oil within the vat and therefore heat exchange occurs between combustion gases in the heat exchange tubes and the oil in the vat through the wall(s) of heat exchange tubes. During frying operations, when oil in the vat is being heated, gaseous fuel is fed to the burners24and combusted at the front of each heat exchange tube, and the combustion gases then traverse the length of the tubes (e.g., from left to right in the side view ofFIG.3) toward the rear side of the fryer, where the combustion gases then move up through an exhaust chimney28formed by a liner30and shell32. Each heat exchange tube22includes an internal baffle40that is configured to promote a flow within the tube that enhances heat exchange from the combustion gases, through the tube wall and to the oil within the vat.

Referring additionally toFIGS.5-10, in one implementation, the baffle40is formed by a plurality of baffle panels42that are interconnected with each other and, here, arranged in a serpentine pattern along a central, lengthwise axis45of the baffle. Each baffle panel includes through openings44. The baffle panels42a-42cthat are located toward the burner facing end46of the baffle40include multiple sets48of openings44, with the openings of each set interconnected with each other by through slits50formed in the baffle panel. These through slits50facilitate thermal expansion of the baffle panels. Such thermal expansion is most important for the baffle panels located closer to the burner end of the heat exchange tube, due to the more extreme heat conditions. Here, the baffle panel42ais located closer to the burner end of the heat exchange tube24than any other baffle panels of the baffle, followed sequentially by baffle panel42band then baffle panel42c

Here, each set48of openings44of the baffle panels42-42ccomprise three openings44a,44b,44c, with one through slit50ainterconnecting the openings44aand44b, and another through slit50binterconnecting the openings44band44c. However, the number of openings included in each set could vary (e.g., only two, or more than three). Here, the openings44a-44care circular and the through slits50aand50bare linear, but other variations are possible. By way of example, a width W50of each through slit may be less than one millimeter, and the width of each through slit50may be no more than ten percent of the diameter of the openings44(e.g., no more than five percent of the diameter). In the case of openings that are not circular, the width of each through slit may be no more than ten percent of a largest cross-dimension of the opening (e.g., no more than five percent of the largest cross-dimension). Here, each baffle panel42a-42cincludes six opening sets48arranged along a height of the baffle panel, but the number and positioning of the opening sets could vary.

Notably, here, each set48of interconnected openings on a panel spans a lateral dimension S48that is at least seventy percent of the total width W42of the panel (e.g., S48at least eighty percent of W42).

The baffle panels42d-42glocated further away from the burner (toward the discharge facing end51of the baffle) also include openings44, but the baffle panels42d-42gdo not have any through slits, because thermal expansion requirements are not as demanding for such baffle panels. The last baffle panel42hincludes larger openings60, but no through slits. The last baffle panel42halso carries a tab62to facilitate positioning of the baffle40into the heat exchange tube from the discharge end of the heat exchange tube.

The subject baffle40promotes effective heat exchange with the tubes22, and at the same time reduces the likelihood of baffle failure.

It is to be clearly understood that the above description is intended by way of illustration and example only, is not intended to be taken by way of limitation, and that other changes and modifications are possible. For example, although the illustrated baffle40includes three baffle panels42a-42that have set of interconnected openings with interconnecting slits and five baffle panels42d-42hthat do not have sets of openings with interconnecting slits, those numbers could vary. Embodiments in which all of the baffle panels have sets of openings with interconnecting through slits are possible.