US4733541A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Constant cooling circuit and system
Assignee: Cambridge Aero Instruments Inc
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Filing: 1986-09-09
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Granted: 1988-03-29
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Expires: 2006-09-09
Abstract
Abstract A circuit for monitoring the heat dissipation capacity of a cooling medium by defining the initial heat dissipation capacity of the medium at a predetermined temperature of a temperature-sensitive element immersed in the medium. The circuit senses a change in temperature of the element and restores the temperature of the element to the predetermined temperature. Based on the level of power required to restore the temperature of the element to the predetermined temperature, the circuit defines the adjustment in heat dissipation capacity of the medium required to return the medium to the initial capacity. Also disclosed is a system including such a circuit which modifies the heat dissipation capacity of the medium by the required adjustment to return the medium to the initial heat dissipation capacity.
Inventors
- 👤 Raouf A. Ismail
- 👤 Suresh Madhavan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:19
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/24; G05D23/1906; G05D23/1913
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
101 words
A circuit for monitoring the heat dissipation capacity of a cooling medium, comprising: means for defining the initial heat dissipation capacity of the cooling medium by imparting a first level of power to a temperature-senstive element immersed in the cooling medium to maintain the temperature of said element at a predetermined temperature; means for sensing a change in temperature of said element; and means, responsive to said means for sensing, for restoring the temperature of said element to said predetermined temperature by altering the power imparted to said element until said predetermined temperature is achieved at a second level of power.
Claim 2
Dependent Claim
101 words
A circuit for monitoring the heat dissipation capacity of a cooling medium, comprising: means for defining the initial heat dissipation capacity of the cooling medium by imparting a first level of power to a temperature-senstive element immersed in the cooling medium to maintain the temperature of said element at a predetermined temperature; means for sensing a change in temperature of said element; and means, responsive to said means for sensing, for restoring the temperature of said element to said predetermined temperature by altering the power imparted to said element until said predetermined temperature is achieved at a second level of power.
Claim 3
Dependent Claim
42 words
The circuit of claim 1 further including means, responsive to said means for restoring, for indicating the differential in power, required to return the element to said predetermined temperature, representative of the corresponding change in the heat dissipation capacity of the medium.
Claim 4
Dependent Claim
26 words
The circuit of claim 2 in which said means for defining includes a bridge circuit having said temperature-sensitive element in one leg of said bridge circuit.
Claim 5
Dependent Claim
22 words
The circuit of claim 3 in which said bridge circuit is balanced by the resistance of said element at said predetermined temperature.
Claim 6
Dependent Claim
49 words
The circuit of claim 4 in which said means for restoring the temperature of said element includes means, responsive to a bridge imbalance, for varying current flow to said bridge circuit to return said temperature-sensitive element to said predetermined temperature and rebalance the bridge at a different voltage level.
Claim 7
Dependent Claim
31 words
The circuit of claim 5 in which said means for indicating represents the change in heat dissipation capacity as the difference in voltage between the first and second bridge balance levels.
Claim 8
Dependent Claim
13 words
The circuit of claim 1 in which said temperature-sensitive element is a thermistor.
Claim 9
Dependent Claim
140 words
A circuit for monitoring the heat dissipation capacity of a cooling medium, comprising: a bridge circuit; one leg of said bridge circuit including a temperature-sensitive resistance set to balance the bridge at a predetermined temperature and heat dissipation level of said temperature-sensitive resistance when immersed in the medium whose heat dissipation capacity is to be monitored; and means, responsive to a bridge imbalance resulting from a change in heat dissipation capacity of the medium, for varying current flow to said bridge to return said temperature-sensitive resistance to said predetermined temperature and heat dissipation level and re-balance the bridge at a different voltage level, the difference in voltage between the first bridge balance level and the second bridge balance level representing the cooling medium heat dissipation adjustment required to maintain said temperature-sensitive resistance at said predetermined temperature and heat dissipation level.
Claim 10
Dependent Claim
140 words
A circuit for monitoring the heat dissipation capacity of a cooling medium, comprising: a bridge circuit; one leg of said bridge circuit including a temperature-sensitive resistance set to balance the bridge at a predetermined temperature and heat dissipation level of said temperature-sensitive resistance when immersed in the medium whose heat dissipation capacity is to be monitored; and means, responsive to a bridge imbalance resulting from a change in heat dissipation capacity of the medium, for varying current flow to said bridge to return said temperature-sensitive resistance to said predetermined temperature and heat dissipation level and re-balance the bridge at a different voltage level, the difference in voltage between the first bridge balance level and the second bridge balance level representing the cooling medium heat dissipation adjustment required to maintain said temperature-sensitive resistance at said predetermined temperature and heat dissipation level.
Claim 11
Dependent Claim
24 words
The circuit of claim 8 in which said means for varying includes means for selectively gating current from a voltage source to said bridge.
Claim 12
Dependent Claim
46 words
The circuit of claim 8 further including means, responsive to the difference in voltage between the first bridge balance level and the second bridge balance level, for determining the heat dissipation adjustment required to maintain said temperature-sensitive resistance at said predetermined temperature and heat dissipation level.
Claim 13
Dependent Claim
13 words
The circuit of claim 8 in which said temperature-sensitive resistance is a thermistor.
Claim 14
Dependent Claim
21 words
The circuit of claim 8 in which said bridge circuit is balanced at a temperature higher than that of the medium.
Claim 15
Independent Claim
162 words
A system for maintaining a cooling medium at a constant heat dissipation capacity, comprising: means for defining the initial heat dissipation capacity of the cooling medium by imparting a first level of power to a temperature-sensitive element immered in the cooling medium to maintain the temperature of said element at a predetermined temperature; means for sensing a change in temperature of said element; means, responsive to said means for sensing, for restoring the temperature of said element to said predetermined temperature by altering the power imparted to said element until said predetermined temperature is achieved at a second level of power; means, responsive to said means for restoring, for indicating the differential in power, required to return the element to said predetermined temperature, representative of the corresponding change in the heat dissipation capacity of the medium; and means, responsive to said means for indicating, for modifying the heat dissipation capacity of the medium return the medium to said initial heat dissipation capacity.
Claim 16
Independent Claim
162 words
A system for maintaining a cooling medium at a constant heat dissipation capacity, comprising: means for defining the initial heat dissipation capacity of the cooling medium by imparting a first level of power to a temperature-sensitive element immered in the cooling medium to maintain the temperature of said element at a predetermined temperature; means for sensing a change in temperature of said element; means, responsive to said means for sensing, for restoring the temperature of said element to said predetermined temperature by altering the power imparted to said element until said predetermined temperature is achieved at a second level of power; means, responsive to said means for restoring, for indicating the differential in power, required to return the element to said predetermined temperature, representative of the corresponding change in the heat dissipation capacity of the medium; and means, responsive to said means for indicating, for modifying the heat dissipation capacity of the medium return the medium to said initial heat dissipation capacity.
Claim 17
Dependent Claim
23 words
The system of claim 13 in which said means for indicating includes means for comparing the levels of power to a reference level.
Claim 18
Dependent Claim
18 words
The system of claim 14 in which said means for comparing includes means for adjusting said reference level.
Claim 19
Dependent Claim
22 words
The system of claim 13 in which said means for modifying includes medium mover means for altering the flow of the medium.
Claim 20
Dependent Claim
20 words
The system of claim 13 in which said means for modifying includes means for adjusting the temperature of the medium.
Claim 21
Dependent Claim
22 words
The system of claim 13 further including cooling failure indicating means for detecting deviations in heat dissipation capacity exceeding a predetermined amount.
References Cited (Backward Citations)
US3125109A
Cited
US4174065A
Cited
US4257552A
Cited
JPS5741719A
Cited
JPS57153139A
Cited
US4476720A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-29 | 1991-09-28 | 1992-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-29 | 1995-09-28 | 1996-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-29 | 1999-09-28 | 2000-03-29 | $7700.00 | Window Closed / Lapsed |