US3738174A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature calibration system
Assignee: King Nutronics LLC
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Filing: 1972-03-01
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Granted: 1973-06-12
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Expires: 1992-03-01
Abstract
Abstract A temperature calibration system including a well for receiving a temperature sensor such as a thermometer or thermocouple, and a heater for heating the well to a desired and adjustable temperature. A single well instrument providing a temperature range of 100* to 600* F. in five steps. A temperature measuring circuit for indicating the temperature of the well and including a temperature sensing element, a temperature signal amplifier, an indicating meter and series diode, and a meter zero reference amplifier, with circuitry for providing substantially linear operation with nonlinear components.
Inventors
- 👤 B Waldron
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:16
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/24; G01; G01K; G01K15/00; G01K15/005
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
200 words
In a temperature measuring circuit for indicating temperature of a unit of a temperature calibration system or the like, the combination of: a temperature sensing element mounted in the unit, with the impedance of said element varying nonlinearly as a first function of temperature; first temperature signal amplifier means with a preset gain and having an input and an output and having a first variable resistor connected between said output and input for setting said gain; a meter for indicating temperature; a rectifier element having an impedance varying nonlinearly as a second function of voltage; a second variable resistor connected across said rectifier element; second temperature reference amplifier means having a present output maintained substantially constant with varying load; a third variable resistor connected to said second amplifier means for setting the output thereof; first circuit means connecting said temperature sensing element to said first amplifier means input; and second circuit means connecting said meter and rectifier element in series between the outputs of said first and second amplifier means; with said first, second and third resistors adjustable to define three points in a straight line in the temperature at said temperature sensing element versus current in said meter relation.
Claim 2
Dependent Claim
200 words
In a temperature measuring circuit for indicating temperature of a unit of a temperature calibration system or the like, the combination of: a temperature sensing element mounted in the unit, with the impedance of said element varying nonlinearly as a first function of temperature; first temperature signal amplifier means with a preset gain and having an input and an output and having a first variable resistor connected between said output and input for setting said gain; a meter for indicating temperature; a rectifier element having an impedance varying nonlinearly as a second function of voltage; a second variable resistor connected across said rectifier element; second temperature reference amplifier means having a present output maintained substantially constant with varying load; a third variable resistor connected to said second amplifier means for setting the output thereof; first circuit means connecting said temperature sensing element to said first amplifier means input; and second circuit means connecting said meter and rectifier element in series between the outputs of said first and second amplifier means; with said first, second and third resistors adjustable to define three points in a straight line in the temperature at said temperature sensing element versus current in said meter relation.
Claim 3
Dependent Claim
72 words
A temperature measuring circuit as defined in claim 1 including: a reference voltage source; a fourth resistor connected in series with said temperature sensing element across said source, with the junction of said resistor and element providing the input to said first amplifier means; and a fifth resistor connected in series with said third resistor across said source, with the junction of said resistors providing the input to said second amplifier means.
Claim 4
Dependent Claim
75 words
A temperature measuring circuit as defined in claim 1 wherein said meter has an output indication movement which is linear between a meter zero position and a meter full scale position, and wherein said third resistor is variable to set said zero position of said meter and said second resistor is variable to set a point intermediate said zero and full scale positions and said first resistor is variable to set said full scale position.
Claim 5
Dependent Claim
30 words
A temperature measuring circuit as defined in claim 1 including third circuit means connecting a feedback signal from the meter-rectifier element junction to the input of said first amplifier means.
Claim 6
Dependent Claim
33 words
A temperature measuring circuit as defined in claim 4 including fourth circuit means connecting a feedback signal from the output of said second amplifier means to the input of said first amplifier means.
Claim 7
Dependent Claim
73 words
A temperature measuring circuit as defined in claim 1 including: a reference voltage source; a plurality of fourth resistors; and a switch for selectively connecting each of said fourth resistors in series with said temperature sensing element across said source; with said first circuit means including a third voltage follower amplifier means having a high input impedance and connecTed between the junction of said resistor and element and said first amplifier means input.
Claim 8
Dependent Claim
83 words
A temperature measuring circuit as defined in claim 6 wherein each of said fourth resistors corresponds to a temperature range, and including a plurality of said first resistors, a plurality of said second resistors, and a plurality of said third resistors, with a separate first, second and third resistor for each of said fourth resistors, and with said switch including means for selecting one of each of said first, second and third resistors for each of the fourth resistors connected by said switch.
References Cited (Backward Citations)
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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) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |