Electric heating – Heating devices – With heating unit structure
Reexamination Certificate
1999-05-12
2001-09-25
Walberg, Teresa (Department: 3742)
Electric heating
Heating devices
With heating unit structure
C219S411000, C219S521000, C392S435000
Reexamination Certificate
active
06294769
ABSTRACT:
BACKGROUND OF THE INVENTION
Many restaurants, and, in particular fast food restaurants, prepare food ahead of its being ordered. This provides the ability to speed the delivery of the food to the customer and to perhaps utilize the cooking appliances for other food items. Certain parts of a meal and, in some cases, entire meals, are prepared in this manner, depending on the restaurant, the time of day, and the food itself.
With regard to the food, some dishes or food items are regularly prepared ahead of time and are sold at a rapid pace throughout the operating hours of the restaurant. One good example of such a food item is the french fries sold by numerous fast food restaurants. The fries are prepared in large batches and are then held in receiving bins prior to being packaged in small containers for sale to consumers.
While being held in the receiving bins, the french fries or other food items are normally kept at whatever serving temperature is deemed appropriate by the particular restaurant. While this temperature will vary depending on the food and the restaurant, it can be generally stated that the food is being kept hot prior to its eventual sale.
There are several disadvantages to the above described practice. For certain foods, the heating or warming process continues the cooking process. The food may thus become overcooked, making its taste, texture, or both, unacceptable. Lowering the temperature may have the same effect on the taste and texture, i.e. it becomes unacceptable. In addition, a lowered temperature often results in the food being cooled below the optimum serving temperature. In order to avoid such problems, many restaurants simply discard food after a certain defined period of time spent in a warming bin or tray. Alternatively, the food may be served or sold at a less than optimum serving temperature, resulting in the food being returned or if consumed, resulting in dissatisfaction of the customer with the restaurant.
Prior art devices of which the applicant is aware are limited to devices used for cooking as opposed to keeping food hot after cooking. For example, U.S. Pat. No. 5,421,942 to Hanzawa et al teaches a device for radiating far infrared radiation in the range of wavelengths of about 4 to 12 microns and higher. Example 7 in this patent teaches the use of the device in cooking, but does not mention the maintenance of temperature over time. U.S. Pat. No. 5,508,495 and U.S. Pat. No. 5,221,829, both to Yahav et al, disclose cooking devices having high thermal shock resistance so as to achieve temperatures of at least 200° C. and up to or exceeding 600° C. As can be seen, these patents do not teach a device that is capable of keeping food hot without continuing the cooking process.
Thus it can be seen that a need exists in the art for a food warming device that maintains food at a substantially constant optimum serving temperature or within an acceptable temperature range and which avoids the disadvantages of the prior art.
SUMMARY OF THE INVENTION
It is, therefore, one if the principal objects of the present invention to provide the ability to maintain a selected food item or items at a selected temperature or within an acceptable temperature range.
Another object of the present invention is to maintain food items at a selected serving temperature or within a selected temperature range for a greater period of time than prior art devices.
A further object of the present invention is to provide a food warming device that is easily constructed and maintained and which is durable to provide a long service life.
These and other objects are attained by the present invention which relates to a food warming device that emits infrared radiation for keeping food at a selected temperature or within a selected temperature range. The device emits infrared radiation at wavelengths between approximately 7.91 to 4.7 microns. The device itself is normally a formed ceramic material with an electric heating element contained therein. A thermocouple is used to control the temperature of the heating element. The temperature range of the element is normally maintained between approximately 200° F. to 650° F. At a temperature within this approximate range, the ceramic emits a micron wavelength, far infrared, within the range specified hereinabove. The ceramic material may have a contoured surface so as to distribute the infrared rays over a larger area.
Various additional objects and advantages of the present invention will become apparent from the following detailed description, with reference to the accompanying drawings.
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Dahbour Fadi H.
Kayden James W.
Thomas Kayden Horstemeyer & Risley
Walberg Teresa
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