Claims
- 1. A method of automatic freezer defrost, comprising the steps of:
determining when a defrost cycle should be initiated based on a predetermined elapsed time, setting a flag which indicates a time to initiate the defrost cycle, monitoring for a low point of the temperature cycle or timeout due to a bottom-out condition, and initiating said defrost cycle.
- 2. The method of claim 1, wherein said flag is set at least six hours after a previous defrost cycle.
- 3. The method of claim 1, wherein the low point is the minimum temperature in the temperature cycle.
- 4. The method of claim 2, further comprising the step of delaying said defrost cycle initiation until the next low point occurs in the temperature cycle.
- 5. The method of claim 1, further comprising the steps of:
deactivating a circulation fan upon initiation of said defrost cycle and reactivating said circulation fan upon the completion of said defrost cycle.
- 6. The method of claim 5, wherein a defrost probe determines when said circulation fan deactivates and reactivates.
- 7. The method of claim 6, wherein said defrost probe must attain at least −15° C. to reactivate said circulation fan after said defrost cycle.
- 8. The method of claim 5, further comprising the step of reactivating said circulation fan after a predetermined time delay.
- 9. A freezer unit, comprising:
an automatic defrost controller, a temperature sensor connected to said controller, a defrost probe connected to said controller, and at least one circulation fan connected to said controller, wherein said controller initiates a defrost cycle at a low point of a temperature cycle as indicated and monitored by said temperature sensor.
- 10. The freezer unit of claim 9, wherein said defrost probe determines when said at least one circulation fan deactivates and reactivates.
- 11. The freezer unit of claim 10, wherein said defrost probe must attain at least −15° C. to reactivate said at least one circulation fan after said defrost cycle.
- 12. The freezer unit of claim 11, wherein said at least one circulation fan reactivates after a predetermined time delay independent of said defrost probe.
- 13. The freezer unit of claim 10, wherein the low point of the temperature cycle is the temperature cycle minimum point.
- 14. The freezer unit of claim 10, wherein said defrost probe is located in said evaporator.
- 15. A freezer unit including a cabinet, evaporator and a compressor, comprising:
means for determining when a defrost cycle should initiate based on a predetermined elapsed time and for checking if a low point in a temperature cycle has been reached, means for setting a flag which indicates a time to initiate a defrost cycle and for monitoring for a low point in the temperature cycle, and means for initiating said defrost cycle once said low point of the temperature cycle has been reached or timeout for bottom-out condition.
- 16. The freezer unit of claim 15, wherein said means for determining when said defrost cycle should initiate and for monitoring for a low point in the temperature cycle is a temperature sensor.
- 17. The freezer unit of claim 16, wherein said means for setting a flag and for initiating said defrost cycle is an embedded microcontroller.
- 18. The freezer unit of claim 17, wherein said defrost probe is located in said evaporator.
- 19. The freezer unit of claim 18, wherein said flag is set at least six hours after a previous defrost cycle.
- 20. The freezer unit of claim 19, wherein the low point of the temperature cycle is the temperature cycle minimum point.
PRIORITY
[0001] The following application claims priority to provisional application entitled Freezer Defrost Method and Apparatus, filed Dec. 3, 2001, herein incorporated by reference.
Provisional Applications (1)
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Number |
Date |
Country |
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60334607 |
Dec 2001 |
US |