Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2002-01-14
2004-08-03
Lee, Benjamin C. (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S588000, C340S686100, C340S521000, C340S545600
Reexamination Certificate
active
06771177
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
BACKGROUND OF THE INVENTION
1) Field of the Invention
The present invention relates generally to food storage containers such as refrigerators. More specifically, the present invention is a self-contained, self-powered, autonomous device that provides and retains visual and audible indications when 1) the refrigerator temperature is appropriate for food storage, 2) the door is left ajar for a period of time, 3) the refrigerator air temperature rises above the USDA recommended food storage limits, 4) the air temperature in the refrigerator has been greater than the USDA recommended food storage limits for an extended period of time, (5) an indication as to the length of time the refrigerator has exceeded recommended food storage temperatures.
2) Description of Prior Art
This invention provides a self-contained, time-based temperature-monitoring device for refrigerators/food storage containers and an integral door open/ajar alarm. Several patents have been issued for inventions in this classification. The one aspect that each invention lacks is the factor of time of exposure. The United States Department of Agriculture (USDA) publishes recommended guidelines for refrigeration and the safe storage of foods. It is the intent of the present invention to provide visual and audible alarm indicator means in accordance with the recommendations set forth by the USDA.
The Food Safety and Inspection Service (FSIS) of the USDA provides consumer information for refrigeration and food storage via their web site at www.fsis.usda.gov. Their information and data that form the basis for this invention are enumerated below and may be found at the aforementioned site.
Bacteria in refrigerated foods are categorized in two (2) families by the FSIS. These families are pathogenic bacteria, those causing foodborne illnesses (i.e.
e coli
, salmonella, etc.) and spoilage bacteria, which cause food to deteriorate thereby causing the food to discolor, emanate an unpleasant odor, etc.
Pathogenic bacteria do not generally affect the taste, smell, or appearance of a food and present no distinguishable characteristics of its existence to the average consumer. Additionally, pathogenic bacteria have been demonstrated to grow rapidly in the “Danger Zone,” temperatures between forty (40) degrees Fahrenheit (F) and one hundred forty (140) degrees F. A spoilage bacterium, on the other hand, results in changes that are perceptible to the unaided senses of the average consumer.
An equally important variable in the equation of food storage safety other than temperature is time. The FSIS has identified that food exposed to temperatures of greater than forty (40) ° F. for a period of more than two (2) hours should not be consumed. The following excerpt is published by the FSIS on their web site:
For safety, it is important to verify the temperature of the refrigerator. Refrigerators should be set to maintain a temperature of 40° F. or below. An appliance thermometer can be kept in the refrigerator to monitor the temperature. This can be critical in the event of a power outage. When the power goes back on, if the refrigerator is still 40° F., the food is safe. Foods held at temperatures above 40° F. for more than 2 hours should not be consumed.
In each of the patents cited, the inventions failed to provide alarm indicator means based upon the length of time the food was exposed to the elevated temperatures.
The present device offers great advantages over current products available to the average consumer. The installation of the unit will be nothing more than cleaning an area on the flat surface on the appliance liner. After exposing the adhesive on the Velcro strips, the installer simply presses the unit to the liner. Ease of interpretation of the visual alarms and audible alarm make it easily understandable to everyone. Perhaps the most valuable advantage of the device is that it retains the alerts until the unit is reset. In the event of a power outage when the appliance is unattended, the present invention shall detect and provide alerts to the appropriate levels, and then maintain these alerts, even in the event that the power is restored and the appliance returns the temperatures to a suitable level.
Typically, the systems now available that provides a means of detecting temperature increases in refrigerators or food storage devices are elaborate. These elaborate systems require significant costs in the purchase, installation, and maintenance of the system. As in the case of the invention cited in U.S. Pat. No. 4,028,688: Refrigeration unit air temperature detection alarm system (1977). This invention consists of a compact alarm system providing remote indications via a communications device in the event the refrigeration unit rises above a predetermined level. This patent requires a Radio Frequency (RF) link, which, upon a predetermined length of time following the temperature rise, issues an alert using telephony. This invention requires a temperature sensing device, sophisticated circuitry to issue an alert, a RF transmitter, a RF receiver, and circuitry to auto-dial and play a recorded message. This invention requires complicated and costly hardware. Additionally, this invention requires the food storage container, or a portion thereof, be permeable to RF at an undetermined frequency, thereby allowing the RF to transmit through the storage device. Since this invention requires electrical power it will not issue alerts in the event external power is interrupted.
Certain existing inventions, because of their complexity, can only be installed during the manufacture of the appliance. As in U.S. Pat. No. 5,460,006: Monitoring system for food storage device (1995), the invention consists of an internal temperature sensing device which provides a control signal to the refrigeration unit thereby providing automatic, real-time feedback allowing for temperature control. This invention requires extensive electrical modification to an existing food storage device, or installation during manufacturing, to ensure appropriate interface between the invention and the cooling unit. As this invention consists of automatic control, it fails to incorporate alerts in 1) the event of increased temperatures and/or 2) the length of duration of food exposure to increased temperatures.
U.S. Pat. No. 5,451,930: Emergency condition, door ajar, and temperature alarm for appliances provides for an invention with a variety of visual and audible alerts. This invention, based upon its alert for an internal occupant, is aimed primarily at commercial units large enough for entry into the storage area. This invention requires mechanical modification to provide for mounting of a switch to alert for an open door. Since the alert is issued externally to the storage compartment, communications via 1) a RF signal and/or 2) a wired system requires additional equipment and modification to the storage compartment. This invention provides for real-time alerts to temperature increases; however, it requires constant monitoring as there are no apparent means of maintaining alerts when the event is not occurring. This invention does not provide an indication to the length of time that the food was exposed to elevated temperatures. Additionally, this invention does not include an autonomous power supply, hence, whenever electrical power is not provided, the alerts will not be issued. Yet another drawback to the existing invention is that the time is set as a prerogative of the operator. This option allows the operator the possibility of setting the control circuitry to a point where the invention issues an alert beyond safe limits.
A number of patents have been issued for inventions that provide alerts when refrigerator, or food storage device, has been left open for a predetermined length of time. U.S. Pat. Nos. 4,528,558, 4,566,285, 4,691,195, 4,707,684, 4,891,626, and 4,894,643 all provide alerts for open containers. The in
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