Electric heating – Inductive heating – With heat exchange
Reexamination Certificate
1999-05-27
2001-02-20
Walberg, Teresa (Department: 3742)
Electric heating
Inductive heating
With heat exchange
C165S104320, 12, 12, C222S427000
Reexamination Certificate
active
06191401
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to containers for delivery of prepared food and particularly of foods which are desirably maintained at an adequate temperature during delivery.
2. Description of the Prior Art
Fast food restaurants have proliferated to such an extent that the percentage of people who frequent these establishments on a regular basis has increased greatly. Among the reasons for this increase is the availability of quickly prepared foods which may be consumed at the restaurant or may be carried out and consumed at a later time. Many such restaurants are equipped with drive though windows to facilitate such take-out service.
Typically, take-out food is placed within a disposable container which, even if equipped with thermal insulated material, does not retain heat for an appreciable amount of time thereby allowing the food contained therein to cool relatively rapidly. Much time and effort has been devoted to make possible the economical delivery of fast food in a satisfactorily hot condition in a disposable heat-retaining food container. For example, U.S. Pat. No. 5,445,286 to Guimarin discloses a heat retentive pizza box having a heating element comprised of water filled pockets which may be preheated in a microwave oven. The microwaved heating element serves to maintain the temperature of the pizza during delivery. Similarly, U.S. Pat. No. 4,567,877 to Sepahpur discloses a heat storage food container including a compartment for holding a microwavable thermal storage medium, such as wet sand. When preheated in a microwave oven, the wet sand retains the heat of the food placed in the container. U.S. Pat. No. 4,777,930 to Hartz and U.S. Pat. No. 5,880,435 to Bostic both disclose food delivery containers having a heat conductive pouch containing a quantity of a latent heat retaining substance which may be preheated to an initial temperature.
A major drawback of each of the above devices is the time required to preheat the heating element. This is particularly disadvantageous with drive-through take-out food service where food orders are delivered rapidly and continuously during the restaurant's peak operating hours. Accordingly, it would be desirable to provide an economical disposable heat maintaining food container which is quickly preheated to a desired temperature.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide an efficient method for maintaining the heat of a food product deposited in a carry out container.
It is another object of the present invention to provide a heat maintaining food container which is rapidly preheated.
It is still a further object of the present invention to provide an economical food container for satisfactorily maintaining the heat of food contained therein.
In accordance with one form of the present invention, the heat maintaining food container generally includes a container having an opening for depositing a food product therein and a ferrous material heated element, which has been preheated to a selected temperature by electromagnetic induction heating, positioned in close proximity to the food product. Preferably, the heated element comprises one or more substantially planar carbon steel sheets having a thickness of about 0.005″ to about 0.030″ and having an insulative layer fixed to at least one side of the sheet. The sheet is preferably unfoldable to take the form of a U-shape or an O-shape for substantially surrounding the food product when placed in the container. Alternatively, the material of the food container may contain a ferrous material wherein the container itself is heated to a selected temperature by electromagnetic induction heating.
A method for maintaining a food product deposited in a container preferably includes the steps of heating a substantially planar carbon steel sheet element to between about 150° F. and about 200° F. by electromagnetic induction heating and placing the sheet within the container in close proximity to the food product. The heated element may be preheated prior to insertion in the container or may be preheated together with the container.
A preferred form of the heat maintaining food delivery container, as well as other embodiments, objects, features and advantages of the invention will be apparent from the following detailed description of illustrative embodiments thereof which is to be read in conjunction with the accompanying drawings.
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Salerno Mark
Salerno Roberta
Hoffmann & Baron , LLP
Pwu Jeffery
Walberg Teresa
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