Stoves and furnaces – Stoves – Cooking
Reexamination Certificate
1999-05-21
2001-06-26
Yeung, James C. (Department: 3743)
Stoves and furnaces
Stoves
Cooking
C126S02100R, C432S145000, C432S176000, C219S400000
Reexamination Certificate
active
06250296
ABSTRACT:
FIELD OF INVENTION
The present invention relates to high heat transfer rate convection ovens utilizing heated jets of air to cook food product and incorporating grease and smoke management features to prevent undesired off-flavor in the food product.
BACKGROUND OF THE INVENTION
The present invention relates to a high velocity convection oven capable of cooking foods that are traditionally cooked by deep fat flying methods, without producing undesired smoke and smoke flavor in the food. More specifically, the oven of the present invention produces high velocity jets of air to cook food product while the food product is moved relative to the air jets, with the preferred method of moving food product being a conveyor assembly. High velocity convection ovens of this type are generally referred to as impingement ovens.
In sum, the oven is characterized by its production of very high transfer rates needed for cooking traditionally deep fat fried foods with air. While conventional impingement type ovens (e.g., see U.S. Pat. No. 4,338,911) have been known to produce heat transfer rates in the range of 12-15 (as measured by a heat transfer rate measurement device of the type described in U.S. Pat. No. 5,161,889), the oven of the present invention is capable of producing heat transfer rates of up to 25 and greater. At the same time, the present oven design also has features which control the amount of smoke produced in the cooking cavity, thereby reducing or eliminating the off-flavor that could be caused by the smoke.
Further, the oven includes dual cavities surrounding the cooking chamber through which room temperature air is circulated. This “cool skin” feature cools the interior walls of the cooking chamber to promote grease collection and retard smoke production. This feature also cools the exterior walls of the oven making the oven safer for use. In addition, the oven of the present invention features an improved air delivery (duct) design that produces more even distribution of temperature controlled cooking gasses to the food product and self-cleaning capabilities using pyrolytic cleaning methods.
SUMMARY OF THE INVENTION
The present invention relates to an improved convection oven with a filtration system for the recirculated convection gas. The oven includes an interior chamber, a product support in the interior chamber and a blower in fluid communication with at least one duct (preferably a plurality) for circulating air into the interior chamber. The duct has a plurality of orifices positioned to direct temperature controlled gas toward the product support. At least one perforated filter plate with a plurality of bends is disposed within the interior chamber separating the interior chamber into a cooking chamber and an air return chamber.
In a preferred embodiment, the plurality comprises accordion folds and the filter plates are disposed in a nested configuration with each other. The bends may also comprise repeating 90 degree bends or a sine curve pattern.
In another aspect of the invention, the filtration system comprises a plurality of louvers disposed in the interior chamber separating the interior chamber into a cooking chamber and an air return chamber, the louvers being downwardly inclined toward the cooking chamber and positioned such that the temperature controlled gas passes through the louvers before returning to the blower for recirculation into the air delivery duct.
In yet another aspect of the invention there is provided a convection oven having an interior chamber comprising a cooking chamber and an air return chamber, a product support disposed within the cooking chamber and a blower in fluid communication with at least one duct for circulating temperature controlled gas into the cooking chamber. The oven includes a return air path whereby at least a portion of the air is returned to the blower after entering the cooking chamber and in the air path there is disposed a catalytic converter.
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Cooper Neal S.
Dobie Michael J.
Dougherty Carl J.
High Jarald E.
Norris John R.
Patentsmith Technology, Ltd.
Sidley Austin Brown & Wood
Yeung James C.
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