Adaptive defrost control system
First Claim
1. In a cooling system having a defrost device and cooled compartment accessible through a door, a defrost control for energizing the defrost device, comprising:
- door sensing means for detecting an initial open period for said door and a subsequent open period when said door remains open beyond said initial open period;
control means for energizing said defrost device at the end of an interval determined at least partly by the cumulative open period of the door, including;
first advance means for advancing toward the end of the interval at a first rate in response to the initial open period to compensate for increased frost occurring during the initial door open period, andsecond advance means for advancing toward the end of the interval at a second rate less than said first rate in response to the subsequent open period to compensate for lesser frost occurring during the subsequent open period.
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Accused Products
Abstract
A refrigerator includes a compressor, an evaporator fan, a condensor fan and a defrost heater which are controlled by a defrost control system. The control senses the number and duration of freezer and fresh food compartment openings, the duration of the previous defrost operation, and the total accumulated compressor run time since the previous defrosting operation. A stored count is decremented by weighting functions which are adaptably varied in accordance with the number and duration of compartment door openings and the duration of the previous defrosting operation. When the stored count is decremented to zero, the defrosting operation may be initiated, unless inhibited. The defrosting operation is inhibited if the total accumulated compressor run time is less than a predetermined amount. The control is reset to a point just short of a defrosting operation if a power outage occurs.
64 Citations
36 Claims
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1. In a cooling system having a defrost device and cooled compartment accessible through a door, a defrost control for energizing the defrost device, comprising:
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door sensing means for detecting an initial open period for said door and a subsequent open period when said door remains open beyond said initial open period; control means for energizing said defrost device at the end of an interval determined at least partly by the cumulative open period of the door, including; first advance means for advancing toward the end of the interval at a first rate in response to the initial open period to compensate for increased frost occurring during the initial door open period, and second advance means for advancing toward the end of the interval at a second rate less than said first rate in response to the subsequent open period to compensate for lesser frost occurring during the subsequent open period. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a cooling system having a defrost device and a cooled compartment accessible through a door, a defrost control for energizing said defrost device, comprising:
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door timing means for measuring the duration of time said door is open, cycle means for energizing said defrost device at the end of a variable defrost interval dependent partly upon the measured door open time, de-energization means for ceasing energization of said defrost device after determining that a frost load has been removed, defrost timing means for measuring the period of time said defrost device has been energized, and adaptive means for varying the manner in which the defrost interval is determined by the measured door open time in response to the time period measured by the defrost timing means. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. In a cooling device having a defrost device and a cooled compartment accessible through a door, a defrost control for energizing the defrost device, comprising:
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door sensing means coupled to said door for indicating when said door is open; door timing means coupled to said door sensing means for detecting an initial open period for said door and a subsequent open period when said door remains open beyond said initial open period; storage means for storing a count; adjust means coupled to said storage means and responsive to said door timing means for varying said count at an adaptably variable rate when said initial open period is detected, said adjust means including fixed means for varying said count at a predetermined rate when said subsequent open period is detected; and control means for actuating said evaporator defrost device to energize said defrost device when said count reaches a predetermined numerical value. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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24. In a cooling system having a defrost device, a compressor, and a cooled compartment accessible through a door, a defrost control for energizing said defrost device, comprising:
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compressor timing means for measuring the cumulative run time of said compressor; door sensing means for detecting an initial open period of said door and a subsequent open period when said door is open beyond said intial open period; control means for energizing said defrost device at the end of a variable interval determined at least partly by the entire door open period of the door, said control means including; first advance means for advancing toward the end of said interval at an adaptably variable rate in response to said detected initial open period; and second advance means for advancing toward the end of said interval at a second rate in response to said detected subsequent open period; de-energization means for ceasing energization of said defrost device after determining that a frost load has been removed; defrost timing means for measuring the period of time said defrost device has been energized; adaptive means for varying said adaptably variable rate in response to the measured time period of the defrost timing means; inhibiting means for inhibiting energization of said defrost device until said compressor run time has reached a minimum value; sensing means for sensing an abnormal operation condition; and adaptive disable means for disabling said adaptive means in response to said sensing means detecting said abnormal condition. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31)
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32. In a cooling device having a defrost device and a cooled compartment accessible through a door, a method of energizing said defrost device at the end of an interval, comprising the steps of:
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sensing the door to determine when said door is open, detecting an initial open period for said door and a subsequent open period when said door remains open beyond said initial open period, advancing toward the end of said interval at a first rate in response to said initial open period, and advancing toward the end of said interval at a second rate, different than the first rate, in response to said subsequent open period.
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33. In a cooling device having a defrost device and a cooled compartment accessible through a door, a method of controlling said defrost device to remove a frost load, comprising the steps of:
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sensing the door to determine when the door is open; detecting an initial open period for said door and a subsequent open period when said door remains open beyond said initial open period; advancing toward the end of an interval at a first rate in response to said initial open period; advancing toward the end of said interval at a second rate different than the first rate in response to said subsequent open period; energizing the defrost device at the end of the interval; de-energizing the defrost device after the frost load has been removed; measuring the length of time said defrost device was energized; comparing the measured length of time against a desired defrost operation duration to obtain a correction factor; and varying the rate of advancement through the next interval in accordance with the correction factor. - View Dependent Claims (34, 35, 36)
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Specification