Refrigeration – Automatic control – Preventing – removing or handling atmospheric condensate
Reexamination Certificate
2001-09-28
2002-12-24
Esquivel, Denise L. (Department: 3744)
Refrigeration
Automatic control
Preventing, removing or handling atmospheric condensate
C062S234000
Reexamination Certificate
active
06497108
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the control of a defrost heater for a refrigerator and specifically to an adaptive control method and apparatus therefor.
2. Related Art
It is known to provide a defrost heater to a refrigeration unit such as in a domestic refrigerator or freezer appliance. In conventional arrangements, the heater is cycled on the basis of electromechanical timers which accumulate time on the basis of compressor operating time, “run time,” or “on time.” When the timer accumulates a predetermined amount of compressor operating time, the defrost heater initiates a defrost cycle, regardless of the current state of various refrigeration components and environment. This can lead to an inefficient use of energy.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, a method for controlling a defrosting apparatus in a refrigerator having a compressor is provided. The method comprises the steps of receiving a demand for defrosting, detecting that the compressor is presently operating, and initiating a defrost cycle after the steps of receiving and detecting.
According to another aspect of the present invention, a method of defrosting a refrigerator or freezer having a compressor and a defrost heater is provided. The method comprises the steps of operating the compressor for a duration and energizing the defrost heater based upon completion of the step of operating the compressor.
According to a further aspect of the present invention, a controller for controlling a defrosting apparatus in a refrigerator having a compressor is provided. The controller comprises a defrost determination means for determining when a defrost cycle is needed, a compressor operation detection means for determining whether the compressor is presently operating, a compressor cycle duration determining means for determining the duration of a prior and a present continuous operation cycle, and a defrost initiation means for initiating a defrost cycle based upon the defrost determination means, the compressor operation detection means and the compressor cycle duration determining means.
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patent: 4843833 (1989-07-01), Polkinghorne
patent: 4879878 (1989-11-01), Polkinghorne
patent: 4959968 (1990-10-01), Fukuda
patent: 4967568 (1990-11-01), Harnden, Jr. et al.
patent: 4989413 (1991-02-01), Fukuda
patent: 5842355 (1998-12-01), Kalis et al.
Collins Martin
Mawby Harold
Esquivel Denise L.
Norman Marc
Pearne & Gordon LLP
White Consolidated Industries, Inc.
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