US3752956A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical resistance heating control circuit
Assignee: EIDP Inc
•
Filing: 1972-05-03
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Granted: 1973-08-14
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Expires: 1992-05-03
Abstract
Abstract Apparatus for maintaining an electrical resistance load at substantially constant operating resistance level utilizing the sensed current and voltage inputs as joint control parameters.
Inventors
- 👤 H Cahill
- 👤 C Erickson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:26
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/24; G05D23/2401
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
148 words
APparatus for maintaining an electrical resistance load having a resistance characteristic varying with temperature at substantially constant operating temperature level comprising, in combination, an electrical power source, means connecting said resistance load to said electrical power source, sensors individually monitoring the voltage and the current supplied to said load, thereby obtaining evaluations of the existing resistance level of said load as functions of the parameters load voltage and load current separately, the output means of said sensors being connected in opposed circuit relationship through a manually settable potentiometer, and power controller means responsive to the position of the tap of said potentiometer and to changes in the outputs of said sensors adjusting concurrently the current and voltage supplied from said electrical power source to said resistance load to maintain the temperature of said reSistance load substantially constant independent of the environment in which said resistance load is located.
Claim 2
Dependent Claim
148 words
APparatus for maintaining an electrical resistance load having a resistance characteristic varying with temperature at substantially constant operating temperature level comprising, in combination, an electrical power source, means connecting said resistance load to said electrical power source, sensors individually monitoring the voltage and the current supplied to said load, thereby obtaining evaluations of the existing resistance level of said load as functions of the parameters load voltage and load current separately, the output means of said sensors being connected in opposed circuit relationship through a manually settable potentiometer, and power controller means responsive to the position of the tap of said potentiometer and to changes in the outputs of said sensors adjusting concurrently the current and voltage supplied from said electrical power source to said resistance load to maintain the temperature of said reSistance load substantially constant independent of the environment in which said resistance load is located.
Claim 3
Dependent Claim
21 words
Apparatus according to claim 1 wherein said electrical power source and said power controller are both of the alternating current type.
Claim 4
Dependent Claim
53 words
Apparatus according to claim 1 wherein said sensors comprise a voltage monitoring resistor connected in shunt with said resistance load, an electric current monitoring resistor connected in series with said resistance load, and, as output means, individual thermistors disposed in close proximity to said voltage monitoring resistor and to said current monitoring resistor.
Claim 5
Dependent Claim
22 words
Apparatus according to claim 1 wherein an amplifier is provided in circuit between said tap of said potentiometer and said power controller.
Claim 6
Dependent Claim
23 words
Apparatus according to claim 1 provided with means limiting the maximum electrical current output of said power controller to said electrical resistance load.
Claim 7
Dependent Claim
22 words
Apparatus according to claim 1 provided with means limiting the initial rate of change of voltage imposed across said electrical resistance load.
Claim 8
Dependent Claim
14 words
Apparatus according to claim 1 wherein said electrical resistance load is a resistance heater.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |