This invention relates to an apparatus and method for determining the time at which to begin and the duration of cooling of an oven for a food product, e.g., a turkey or similar meat product, and preferably one that is cooked by radio frequency ("RF") radiation.
Food preparation is typically a part of the tradition during holidays, celebrations, and special occasions. The food for such occasions, however, generally has to be prepared by a skilled cook, a chef, or other person who is familiar with the food in order to be safe, or to achieve a desired taste. Such persons are not always available. The same is true with respect to the apparatus used to cook such food. Accordingly, apparatus and methods have been developed to allow persons without such knowledge or skills to prepare food for special occasions, as well as to conserve the quality of food and to reduce the time needed to cook it.
One such apparatus is a microwave oven, which cooks food rapidly, due to the conversion of electromagnetic energy to heat energy. Another apparatus that is commonly used for cooking is a convection oven, which cooks the food in a hot, non-insulated environment, thereby conserving energy and increasing the speed at which the food is cooked. Microwave ovens are, however, disadvantageous in that they operate at a frequency that is generally limited to less than about 300 MHz. Such a frequency range may result in unsatisfactory cooking of the food or undesirably overcooking of the food. Such overcooking is undesirable, as it may lead to charred or "burned" food that may be unsuitable for eating. Microwave ovens also typically suffer from limited heating capability and require relatively long preheat times. Additionally, microwave ovens typically have relatively small heating capabilities, typically in the range of about 0.1 to about 0.5 cubic feet per minute ("cfm"), compared to about 2 to about 5 cfm for convection ovens.
It is also known to employ infrared ("IR") energy in the range of about 500 nm to about 1000 nm to cook food, as IR radiation is known to penetrate through the skin. Such IR energy may be desirable for some cooking situations and may be beneficial in conserving energy and reducing the cooking time, as IR radiation is typically emitted by the heated food, and the energy is re-radiated toward and/or absorbed by the heated food. Conventional IR energy ovens, however, typically operate at power levels that are too low to provide adequate cooking capability, and most of these ovens do not provide any control over the cooking temperature of the food product. The ovens also do not have a simple, user-friendly method for easily regulating and controlling the cooking temperature of the food product.
Another conventional method of cooking food employs microwave energy in combination with an electric oven, typically in a microwave oven/convection oven combination. This combination generally allows the time and temperature of the microwave energy to be controlled and to be set to values in the standard oven temperature/time tables. Such ovens, however, typically use an iron core of an oven that is capable of heating the food. Such conventional IR energy ovens may also suffer from the limited heating capability discussed above.
Such conventional convection ovens and microwave ovens suffer from additional disadvantages. Many of the ovens employ sensors and control units that are separate from one another. That is, to operate a conventional convection oven, it is necessary to place the food product in a particular location within the oven, turn on the convection heating unit to initiate the baking cycle, and then watch and adjust the temperature dial to maintain the proper baking temperature for the food. Such conventional ovens may also have a user-interaction unit having a number of switches or knobs that allow a user to select the type of food to be baked, whether the food is frozen or fresh, how long the food is to be baked, and/or other operational settings.
In order to effectively control and monitor the temperature of the food product in conventional ovens, the controllers, sensors, and user-interaction units generally require accurate temperature readings from the oven. These readings, however, may be inaccurate in several respects. For instance, food products may be stacked within ovens and convection ovens may have a conveyor belt. The conveyor belt may allow the temperature of the products being conveyed to rise above that of the temperature sensors of the oven that are positioned at a distance from the product. This over-temperature condition may adversely affect the precision of the temperature sensor reading and/or result in errors in the desired temperature set point.
It is also known to heat food items in food package trays by RF radiation. See, for instance, U.S. Pat. No. 5,304,081 to Nieuwenhuizen, which is incorporated herein by reference. In Nieuwenhuizen, food packages are placed in contact with a ceramic element that is designed to heat the contents of the package. Such conventional apparatus, however, only heat the food items and do not measure or regulate the temperature of the food items to control the cooking time or the quality of the cooking.
There is a need, therefore, for an apparatus and method for cooking food items, such as the time and temperature of cooking for a turkey, or similar food product, that may also provide for a desired time and temperature during cooking, that may be used at different times and with a plurality of different food items, and that does not suffer from the disadvantages described above. Such an apparatus and method preferably use IR energy, do not require a separate control unit for controlling and monitoring the food product temperature, are not large and do not require a conveyor belt, are easily manufactured, are easily controlled and monitored by a user, may be used with a turkey rack, and/or other food product, and/or is capable of quickly raising the food product temperature to a desired level.
The present invention also relates to a method and apparatus for automatically maintaining the product temperature of a product in a manner that conserves energy and reduces the cooking time. Such an apparatus and method should also be easy to control and should be cost-effective to implement. The apparatus and method should preferably provide a temperature profile for the product which may be easily measured and/or obtained, should be capable of achieving and/or maintaining a desired product temperature over a desired time and should be easily controlled and monitored. Such an apparatus and method would preferably also provide a food product temperature profile which may be utilized by a system controller to control and regulate the cooking process in order to provide food items of desired quality and weight. The present invention is also directed to a method for controlling a food product's cooking process that allows the temperature of the food product to be closely controlled.
In this regard, the present invention is directed to an apparatus and method for determining the time and duration of cooking a food product. According
