USH562H
Expired / Lapsed
US
⏱️ 0.0 years remaining
Accurate electronic thermometer
Assignee: United States Department of the Army
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Filing: 1986-11-28
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Granted: 1988-12-06
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Expires: 2006-11-28
Abstract
Abstract A device is disclosed for accurately measuring temperature electronically, having a resistance-type sensor, such as a thermistor, used with a constant current to develop a voltage thereacross. Operational amplifier circuits provide a linear relationship between sensor voltage and resistance. The sensor's calculated resistance is used in a microprocessor to solve a log-polynomial equation relating resistance to temperature. Software corrections compensate for temperature-related variations in the circuitry, and a keyboard permits entry of the polynomial coefficients relating the sensor's output to the measured temperature, to allow interchangeability of sensors. The components are packaged in a compact, waterproofed container to provide a rugged, portable instrument usable in extremes of climatic conditions and capable of maintaining high accuracy over a wide temperature range.
Inventors
- 👤 Gary M. Trachier
- 👤 James S. Morse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:37
CPC Classifications
G; G01; G01K; G01K7/00; G01K7/42
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
150 words
A temperature measuring apparatus of the type wherein the electrical resistance characteristic of a thermal sensor is measured and used to determine temperature, comprising: a resistance-type thermal sensor having a temperature-resistance relationship given by ##EQU2## where: T is temperature, in degrees Celsius; R is the sensor's electrical resistance, in Ohms; and A, B and C are calibration constants for the sensor: means for providing a substantially constant electrical current to said sensor; means for measuring the voltage produced across said sensor at said constant current, said voltage varying according to changes in the temperature of said sensor; means for determining the resistance of said sensor from said voltage in accordance with Ohm's law, and for determining the sensor's temperature from said temperature-resistance relationship; means for displaying said determined temperature; and means for providing said sensor calibration constants A, B ,C to said determining means for the determination of said temperature.
Claim 2
Dependent Claim
150 words
A temperature measuring apparatus of the type wherein the electrical resistance characteristic of a thermal sensor is measured and used to determine temperature, comprising: a resistance-type thermal sensor having a temperature-resistance relationship given by ##EQU2## where: T is temperature, in degrees Celsius; R is the sensor's electrical resistance, in Ohms; and A, B and C are calibration constants for the sensor: means for providing a substantially constant electrical current to said sensor; means for measuring the voltage produced across said sensor at said constant current, said voltage varying according to changes in the temperature of said sensor; means for determining the resistance of said sensor from said voltage in accordance with Ohm's law, and for determining the sensor's temperature from said temperature-resistance relationship; means for displaying said determined temperature; and means for providing said sensor calibration constants A, B ,C to said determining means for the determination of said temperature.
Claim 3
Dependent Claim
20 words
An apparatus as set forth in claim 1, wherein said means for providing said sensor calibration constants comprises a keyboard.
Claim 4
Dependent Claim
37 words
An apparatus as set forth in claim 2, wherein said determining means comprises processor circuitry provided with logic to determine the resistance of said sensor and said temperature, and to provide said temperature to said display means.
Claim 5
Dependent Claim
23 words
An apparatus as set forth in claim 3, wherein said processor circuitry further includes logic to correct said measured voltage for temperature-dependent variations.
Claim 6
Dependent Claim
15 words
An apparatus as set forth in claim 4, wherein said thermal sensor is a thermistor.
Claim 7
Dependent Claim
139 words
A temperature measuring system of the type wherein the electrical resistance of a thermal sensor is measured and used to determine temperature, comprising: a thermistor sensor having a temperature-resistance relationship given by ##EQU3## where: T is temperature, in degrees Celsius; R is the sensor's electrical resistance, in Ohms; and A, B and C are calibration constants for the sensor; a source of substantially-constant electrical current; circuitry for measuring the voltage across said sensor at said constant current, said voltage varying according to changes in the temperature of said sensor; computing logic means for determining the resistance of said sensor from said voltage and for determining the sensor's temperature from said temperature-resistance relationship; digital display means for displaying said determined temperature; and data entry means for providing said computing logic means with said sensor calibration constants A, B, and C.
Claim 8
Dependent Claim
139 words
A temperature measuring system of the type wherein the electrical resistance of a thermal sensor is measured and used to determine temperature, comprising: a thermistor sensor having a temperature-resistance relationship given by ##EQU3## where: T is temperature, in degrees Celsius; R is the sensor's electrical resistance, in Ohms; and A, B and C are calibration constants for the sensor; a source of substantially-constant electrical current; circuitry for measuring the voltage across said sensor at said constant current, said voltage varying according to changes in the temperature of said sensor; computing logic means for determining the resistance of said sensor from said voltage and for determining the sensor's temperature from said temperature-resistance relationship; digital display means for displaying said determined temperature; and data entry means for providing said computing logic means with said sensor calibration constants A, B, and C.
Claim 9
Dependent Claim
16 words
A system as set forth in claim 6, wherein said data entry means comprises a keyboard.
Claim 10
Dependent Claim
34 words
A system as set forth in claim 7, wherein said source of substantially-constant current comprises: a battery power source; and circuitry to convert the voltage from said battery power source to a constant current.
Claim 11
Dependent Claim
27 words
A system as set forth in claim 8, wherein said conversion circuitry includes operational amplifier circuitry to provide said sensor voltage linearly proportional to said sensor resistance.
Claim 12
Dependent Claim
37 words
A system as set forth in claim 9, wherein said determining means comprises processor circuitry provided with logic to determine the resistance of said sensor and said temperature, and to provide said temperature to said display means.
Claim 13
Independent Claim
144 words
A method for measuring temperature wherein the electrical resistance characteristic of a thermal sensor is measured and used to determine temperature, comprising: using a resistance-type thermal sensor to measure the temperature, said sensor having a temperature-resistance relationship given by ##EQU4## where: T is temperature, in degrees Celsius; R is the sensor's electrical resistance, in Ohms; and A, B and C are calibration constants for the sensor: applying a substantially constant electrical current to said sensor; measuring the voltage produced across said sensor at said constant current, said voltage varying according to changes in the temperature of said sensor; determining the resistance of said sensor from said voltage in accordance with Ohm's law; providing said calibration constants A, B C for the sensor being used for the determination of said temperature, and determining the sensor's temperature from said temperature-resistance relationship; and displaying said determined temperature.
Claim 14
Independent Claim
144 words
A method for measuring temperature wherein the electrical resistance characteristic of a thermal sensor is measured and used to determine temperature, comprising: using a resistance-type thermal sensor to measure the temperature, said sensor having a temperature-resistance relationship given by ##EQU4## where: T is temperature, in degrees Celsius; R is the sensor's electrical resistance, in Ohms; and A, B and C are calibration constants for the sensor: applying a substantially constant electrical current to said sensor; measuring the voltage produced across said sensor at said constant current, said voltage varying according to changes in the temperature of said sensor; determining the resistance of said sensor from said voltage in accordance with Ohm's law; providing said calibration constants A, B C for the sensor being used for the determination of said temperature, and determining the sensor's temperature from said temperature-resistance relationship; and displaying said determined temperature.
Claim 15
Dependent Claim
20 words
A method as set forth in claim 11, further comprising correcting the measured voltage across said sensor for temperature-dependent variations.
Claim 16
Dependent Claim
14 words
A method as set forth in claim 12, wherein said sensor is a thermistor.
Claim 17
Dependent Claim
17 words
A method as set forth in claim 13, wherein said calibration constants are provided with a keyboard.
Claim 18
Dependent Claim
41 words
A method as set forth in claim 14, further comprising changing the thermal sensor to a different sensor having a second set of calibration constants, and providing said second set of constants for said different sensor via entry with said keyboard.
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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) | 1991-12-06 | 1992-06-06 | 1992-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-06 | 1996-06-06 | 1996-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-06 | 2000-06-06 | 2000-12-06 | $7700.00 | Window Closed / Lapsed |