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Publication Date: 2010-Nov-05
Document File: 4 page(s) / 1M

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The Prior Art Database


The present invention discloses a multiple thermistor refrigeration control technique. The multiple thermistor refrigeration technique comprises four thermistors that provide an electrical averaging of temperatures for increased accurate readings with one input. Different configurations of thermistors are provided for different purposes such as, electrical averaging of temperatures between upper to lower section of the compartment, right to left section of the compartment, and also for cross compartment averaging of the refrigerator.

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The present invention relates generally to home appliances, and more particularly to the use of multiple thermistors in a refrigerator.

Maintaining an optimum temperature that is typically below ambient temperature is desirable for efficient storage of perishable food. Thermistors have been used in temperature control systems to measure temperature variations in a variety of devices, including refrigerators. By measuring change in voltage as resistance changes, the temperature around the thermistor can be determined. It is advantageous to use a thermistor to measure temperature variations in devices such as home appliances because of their high sensitivity to small temperature changes. Additionally, thermistors are commonly very small in size and can be easily integrated into many devices. 

Refrigerators commonly contain one or more thermistors that are placed in open spaces within a fresh food compartment and a freezer compartment. While these placements facilitate measurement of the respective compartment temperature, the locations may not be ideal for the operation of the thermistor. Placement within the colder air of the refrigerator compartments can affect the thermistor’s ability to accurately measure compartment temperature changes. Also, the thermistor’s operation is affected when airflow to the device becomes obstructed by food items stored on the shelves in the compartments.  One key noise parameter (KNP) is the positioning of warm food items near a sensing point of a thermistor. The placing of the warm food items near the thermistor affects the temperature reading of that thermistor, and thus may result in over-cooling of the refrigerator compartment.

In order to prevent over-cooling of the refrigerator compartment that may result after a warm food item is placed near a thermistor, conventional techniques include changing the thermistor position to a location that is less likely to be blocked by a user’s loading of food items. However, such conventional techniques are not adequate to stop the frequent over cooling. 

As a result, there exists a need for a technique that avoids overcooling of the refrigerator compartment without affecting a user’s preference for loading food items into the refrigerator.



Figure 1 is an exemplary embodiment of multiple thermistors in accordance with the present invention.

Figure 2 is a configuration with four thermistors in accordance with one embodiment of the present invention.


Figure 3 is another configuration with four thermistors in accordance with another embodiment of the present invention.

Figure 4 is a graphical illustration showing the effect of the introduction of a warm food item near a thermistor in accordance with one embodiment of the present invention.



The present invention discloses a multiple thermistor refrigeration control technique. The multiple thermistor...