Patent US5528908A successfully refreshed from Google Patents.
US5528908A
Expired / Lapsed
US
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Blocked fan detection system for heat pump
Assignee: Copeland LP
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Filing: 1995-06-06
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Granted: 1996-06-25
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Expires: 2015-06-06
Abstract
Abstract The blocked fan or obstructed airflow condition is detected by measuring the difference between outdoor air temperature and outdoor exchanger coil temperature. If a very high difference is detected, or if no decrease in the difference is achieved after termination of the defrost cycle, and if either of these conditions persists over a plurality of defrost cycles, then the blocked condition is declared. The diagnostic system can be integrated in an existing demand defrost cycle and is capable of detecting blocked conditions attributable to foreign matter such as leaves, paper and debris which cannot be cleared by defrosting.
Inventors
- 👤 Vijay Bahel
- 👤 Hank Millet
- 👤 Mickey Hickey
- 👤 Hung Pham
- 👤 Gregory P. Herroon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:26
CPC Classifications
F; F25; F25D; F25D21/00; F25D21/02; F25B; F25B47/00; F25B47/02; F24; F24F; F24F11/00; F24F11/30; F25B13/00; F25B49/00; F25B49/005; F25B49/02; F25B49/027; F25D21/002; F25D21/006; F24F11/41; F25B2313/00; F25B2313/029; F25B2313/0293; F25B2313/0294; F25B2313/031; F25B2313/0315; F25B2347/00; F25B2347/02; F25B2347/023; F25B2600/00; F25B2600/11; F25B2600/111; F25B2600/112; F25B2600/25; F25B2600/2513; F25B2700/00; F25B2700/21; F25B2700/2103; F25B2700/2106; F25B2700/2115; F25B2700/21152; Y; Y02; Y02B; Y02B30/00; Y02B30/70
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
105 words
An airflow obstruction detection method for detecting an airflow obstruction condition in an outdoor heat exchanger, comprising the steps of: determining a temperature difference parameter indicative of temperature difference between the outdoor heat exchanger and the ambient air surrounding said heat exchanger at a first time; performing a defrost cycle when the temperature difference parameter exceeds a predetermined value; determining the temperature difference parameter at a second time after defrost cycle has completed; declaring an obstruction condition to exist if the temperature difference parameter determined at said second time is not smaller by a predetermined value than the temperature difference determined at said first time.
Claim 2
Dependent Claim
105 words
An airflow obstruction detection method for detecting an airflow obstruction condition in an outdoor heat exchanger, comprising the steps of: determining a temperature difference parameter indicative of temperature difference between the outdoor heat exchanger and the ambient air surrounding said heat exchanger at a first time; performing a defrost cycle when the temperature difference parameter exceeds a predetermined value; determining the temperature difference parameter at a second time after defrost cycle has completed; declaring an obstruction condition to exist if the temperature difference parameter determined at said second time is not smaller by a predetermined value than the temperature difference determined at said first time.
Claim 3
Dependent Claim
66 words
The method of claim 1 wherein said step of a first time determining a temperature difference comprises the steps of determining a first parameter indicative of the average temperature of the outdoor heat exchanger, determining a second parameter indicative of the average ambient air temperature in the vicinity of the outdoor heat exchanger, and using said first and second parameters to calculate the temperature difference parameter.
Claim 4
Dependent Claim
66 words
The method of claim 1 wherein said step of a second time determining a temperature difference comprises the steps of determining a first parameter indicative of the average temperature of the outdoor heat exchanger, determining a second parameter indicative of the average ambient air temperature in the vicinity of the outdoor heat exchanger, and using said first and second parameters to calculate the temperature difference parameter.
Claim 5
Dependent Claim
42 words
The method of claim 1 wherein said step of performing a defrost cycle comprises the steps of determining an air temperature parameter indicative of the temperature ambient air surrounding said heat exchanger and using said air to obtain said predetermined value temperature.
Claim 6
Dependent Claim
19 words
The method of claim 1 further comprising implementing a lockout timer to restrain the performing of said defrost cycle.
Claim 7
Dependent Claim
43 words
The method of claim 5 wherein said lockout timer is reset in connection with said defrost cycle performing step and wherein said lockout timer prevents the subsequent defrost cycle performing step for a predetermined time determined at least in part by said reset.
Claim 8
Dependent Claim
22 words
The method of claim 1 further comprising performing a predetermined time delay between said defrost cycle performing step and said second time.
Claim 9
Dependent Claim
23 words
The method of claim 7 wherein said predetermined time delay is chosen to allow the temperature difference to stabilize following the defrost cycle.
Claim 10
Dependent Claim
14 words
The method of claim 7 wherein said predetermined time delay is about fifteen minutes.
Claim 11
Dependent Claim
18 words
The method of claim 7 further comprising shutting off the fan in response to a detected obstruction condition.
Claim 12
Dependent Claim
40 words
The method of claim 7 wherein said outdoor heat exchanger has associated with it a compressor for pumping refrigerant through said heat exchanger and wherein said method further comprises turning off the compressor in response to a detected obstruction condition.
Claim 13
Dependent Claim
42 words
The method of claim 7 wherein said outdoor heat exchanger has associated with it an expansion valve for regulating refrigerant flow through said heat exchanger and wherein said method further comprises closing the expansion valve in response to a detected obstruction condition.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-06-25 | 1999-12-25 | 2000-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-25 | 2003-12-25 | 2004-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-25 | 2007-12-25 | 2008-06-25 | $7700.00 | Window Closed / Lapsed |