Patent EP0327249A2 successfully refreshed from Google Patents.
Patent US3754442A successfully refreshed from Google Patents.
US3754442A
Expired / Lapsed
US
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Temperature measuring system producing linear output signal from non-linear sensing resistance
Assignee: INSTRULAB Inc
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Filing: 1970-12-01
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Granted: 1973-08-28
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Expires: 1990-12-01
Abstract
Abstract A temperature measuring and indicating system producing an electrical output signal which is substantially a linear function of the temperature sensed by a temperature sensitive resistance element which has a non-linear temperature resistance characteristic. One or more operational amplifiers or other current generators are used to excite the resistance temperature sensing element. The voltage generated across the temperature sensitive resistance element is sensed. Through a current generator a signal is induced in the temperature sensitive resistance element which is proportional to the difference between a given reference temperature and a temperature sensed by the temperature sensitive resistance element.
Inventors
- 👤 C Arnett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:36
CPC Classifications
G; G01; G01K; G01K7/00; G01K7/16; G01K7/18; G01K7/20; G01K7/21
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
367 words
Temperature measuring apparatus comprising: a resistance Temperature detector element having an electrical resistance versus temperature characteristic which differs in a slight and systematic manner from a linear first order mathematical expression relating resistance and temperature, means for sensing the voltage generated across said resistance temperature detector element as current flows therein and for providing an electrical output voltage signal indicative thereof, means for inducing only in said resistance temperature detector element a constant and temperature invariant first electrical current having an amplitude that generates across said resistance temperature detector element a convenient and predetermined increment of voltage for each degree of temperature change incurred by said resistance temperature detector element, means responsive to said electrical output voltage signal for inducing only in said resistance temperature detector element in summation with said first electrical current a second electrical current which is smaller than said first electrical current and which is proportional to said electrical output voltage signal, whereby said second electrical current has an amplitude of zero when the temperature of the resistance temperature detector element is a given reference temperature, the electrical output voltage signal being zero when the temperature of the resistance temperature detector element is equal to said given reference temperature, at any other temperature of the resistance temperature detector element the second electrical current having an amplitude which is proportional to the difference between said given reference temperature and said other temperature, said means including means for creating across only the resistance temperature detector element a voltage resulting from both induced currents, which voltage has a substantially constant change with respect to temperature change, whereby the resultant current flowing in said resistance temperature detector element is not a current of constant amplitude which generates a voltage reproductive of the resistance char-acteristic of the resistance temperature detector element which differs in a slight and systematic manner from a linear first order mathematical expression, the resultant current, instead, being a varying temperature related current which generates only across said resistance temperature detector element a voltage which is more nearly a straight line function of the temperature thereof and in which the voltage has values greater than and less than the straight line function of temperature values.
Claim 2
Dependent Claim
367 words
Temperature measuring apparatus comprising: a resistance Temperature detector element having an electrical resistance versus temperature characteristic which differs in a slight and systematic manner from a linear first order mathematical expression relating resistance and temperature, means for sensing the voltage generated across said resistance temperature detector element as current flows therein and for providing an electrical output voltage signal indicative thereof, means for inducing only in said resistance temperature detector element a constant and temperature invariant first electrical current having an amplitude that generates across said resistance temperature detector element a convenient and predetermined increment of voltage for each degree of temperature change incurred by said resistance temperature detector element, means responsive to said electrical output voltage signal for inducing only in said resistance temperature detector element in summation with said first electrical current a second electrical current which is smaller than said first electrical current and which is proportional to said electrical output voltage signal, whereby said second electrical current has an amplitude of zero when the temperature of the resistance temperature detector element is a given reference temperature, the electrical output voltage signal being zero when the temperature of the resistance temperature detector element is equal to said given reference temperature, at any other temperature of the resistance temperature detector element the second electrical current having an amplitude which is proportional to the difference between said given reference temperature and said other temperature, said means including means for creating across only the resistance temperature detector element a voltage resulting from both induced currents, which voltage has a substantially constant change with respect to temperature change, whereby the resultant current flowing in said resistance temperature detector element is not a current of constant amplitude which generates a voltage reproductive of the resistance char-acteristic of the resistance temperature detector element which differs in a slight and systematic manner from a linear first order mathematical expression, the resultant current, instead, being a varying temperature related current which generates only across said resistance temperature detector element a voltage which is more nearly a straight line function of the temperature thereof and in which the voltage has values greater than and less than the straight line function of temperature values.
Claim 3
Dependent Claim
133 words
The apparatus of claim 1 in which the means for inducing only in said resistance temperature detector element a constant and invariant first electrical current includes a relatively small voltage source having internal resistance, capable of exciting said resistance temperature detector element, and in which the means responsive to said electrical output signal includes a signal path to said relatively small voltage source having an internal resistance, and in which the apparatus includes a temperature indicator instrument, and means connecting the temperature indicating instrument to the small voltage source having an internal resistance, whereby the voltage of the small voltage source having an internal resistance is subtracted from the voltage applied to the temperature indicating instrument and said apparatus provides an output signal free of offset voltages without the use of bridge circuitry.
Claim 4
Dependent Claim
242 words
An electrical circuit for exciting a temperature sensing electrical resistance element having an electrical resistance characteristic differing from a straight line condition of resistance versus temperature by successively larger increments of resistance at successive temperatures which are increasingly removed from a reference temperature at which the electrical output of the current is zero to produce an electrical voltage across said temperature sensing electrical resistance element which has a substantIally linear relationship with the temperature thereof, said electrical circuit comprising: an operational amplifier connected for the linear mode of operation and having input means including a summing node input terminal, the operational amplifier having an output signal responsive current path, means for connecting the temperature sensing electrical resistance element to the summing node terminal and within the output signal responsive feedback current path associated with said operational amplifier, a source of constant and temperature invariant electrical signal, means joining the input means of the operational amplifier to the source of constant and temperature invariant electrical signal for inducing a constant and temperature invariant current of predetermined magnitude only in said temperature sensing electrical resistance element, a source of temperature dependent electrical voltage signal having a magnitude which changes in proportion to the temperature difference between the temperature of the temperature sensing resistance element and said reference temperature, means for connecting the source of temperature dependent electrical voltage signal to said input means of the operational amplifier and to the temperature sensing resistance element.
Claim 5
Dependent Claim
242 words
An electrical circuit for exciting a temperature sensing electrical resistance element having an electrical resistance characteristic differing from a straight line condition of resistance versus temperature by successively larger increments of resistance at successive temperatures which are increasingly removed from a reference temperature at which the electrical output of the current is zero to produce an electrical voltage across said temperature sensing electrical resistance element which has a substantIally linear relationship with the temperature thereof, said electrical circuit comprising: an operational amplifier connected for the linear mode of operation and having input means including a summing node input terminal, the operational amplifier having an output signal responsive current path, means for connecting the temperature sensing electrical resistance element to the summing node terminal and within the output signal responsive feedback current path associated with said operational amplifier, a source of constant and temperature invariant electrical signal, means joining the input means of the operational amplifier to the source of constant and temperature invariant electrical signal for inducing a constant and temperature invariant current of predetermined magnitude only in said temperature sensing electrical resistance element, a source of temperature dependent electrical voltage signal having a magnitude which changes in proportion to the temperature difference between the temperature of the temperature sensing resistance element and said reference temperature, means for connecting the source of temperature dependent electrical voltage signal to said input means of the operational amplifier and to the temperature sensing resistance element.
Claim 6
Dependent Claim
35 words
The electrical circuit of claim 3 in which the operational amplifier has a second input terminal and which includes means connecting the second input terminal to the source of constant and temperature invariant electrical signal.
Claim 7
Dependent Claim
33 words
The electrical circuit of claim 3 in which the operational amplifier has a second input terminal and which includes means connecting the second input terminal to the source of temperature dependent electrical signal.
Claim 8
Dependent Claim
28 words
The electrical circuit of claim 3 which includes means connecting the summing node terminal of the operational amplifier to the source of constant and temperature invariant electrical signal.
Claim 9
Dependent Claim
26 words
The electrical circuit of claim 3 which includes means connecting the summing node terminal of the operational amplifier to the source of temperature dependent electrical signal.
Claim 10
Dependent Claim
43 words
The electrical circuit of claim 3 in which the operational amplifier has an output terminal and in which the output signal responsive current path associated with said operational amplifier includes circuit means located between the output terminal and the sumning node input terminal.
Claim 11
Dependent Claim
291 words
An electrical circuit for exciting a temperature sensing electrical resistance element having an electrical resistance characteristic differing from a straight line curve of resistance versus temperature by successively larger increments of resistance at successive temperatures which are increasingly removed from a reference temperature at which the electrical output of the current is zero, to produce an electrical voltage across said temperature sensing electrical resistance element which has a substantially linear relationship with the temperature thereof, said electrical circuit comprising: an operational amplifier connected for the linear mode of operation and having input means including a summing node input terminal, means for connecting the temperature sensing electrical resistance element to the summing node terminal and within the output signal responsive feedback current path associated with said operational amplifier, a source of constant and temperature invariant electrical signal, means joining the input means of the operational amplifier to the source of constant and temperature invariant electrical signal for inducing a constant and temperature invariant current of predetermined magnitude in said temperature sensing electrical resistance element, a source of temperature dependent electrical voltage signal having a magnitude which changes in proportion to the temperature difference between the temperature of the temperature sensing resistance element and said reference temperature, means for connecting the source of temperature depeNdent electrical voltage signal to said input means of the operational amplifier, a differential amplifier circuit, including an operational amplifier device, resistive network means connected to the operational amplifier device and including input terminal means, means for connecting said input terminal means to the temperature sensing electrical resistance element, the differential amplifier circuit responding to a differential signal received from the temperature sensing electrical resistance element and rejecting common mode signals received from the temperature sensing electrical resistance element.
Claim 12
Dependent Claim
291 words
An electrical circuit for exciting a temperature sensing electrical resistance element having an electrical resistance characteristic differing from a straight line curve of resistance versus temperature by successively larger increments of resistance at successive temperatures which are increasingly removed from a reference temperature at which the electrical output of the current is zero, to produce an electrical voltage across said temperature sensing electrical resistance element which has a substantially linear relationship with the temperature thereof, said electrical circuit comprising: an operational amplifier connected for the linear mode of operation and having input means including a summing node input terminal, means for connecting the temperature sensing electrical resistance element to the summing node terminal and within the output signal responsive feedback current path associated with said operational amplifier, a source of constant and temperature invariant electrical signal, means joining the input means of the operational amplifier to the source of constant and temperature invariant electrical signal for inducing a constant and temperature invariant current of predetermined magnitude in said temperature sensing electrical resistance element, a source of temperature dependent electrical voltage signal having a magnitude which changes in proportion to the temperature difference between the temperature of the temperature sensing resistance element and said reference temperature, means for connecting the source of temperature depeNdent electrical voltage signal to said input means of the operational amplifier, a differential amplifier circuit, including an operational amplifier device, resistive network means connected to the operational amplifier device and including input terminal means, means for connecting said input terminal means to the temperature sensing electrical resistance element, the differential amplifier circuit responding to a differential signal received from the temperature sensing electrical resistance element and rejecting common mode signals received from the temperature sensing electrical resistance element.
Claim 13
Dependent Claim
25 words
The electrical circuit of claim 9 which includes means joining the source of temperature dependent electrical signal to the output of said operational amplifier device.
Claim 14
Dependent Claim
166 words
Temperature responsive apparatus comprising in combination: a thermally responsive resistor element detecting the temperature of a given environment, the thermally responsive resistor element having a resistance characteristic which is non-linear with respect to temperature, means inducing directly into the thermally responsive resistor element a current of constant magnitude, means inducing directly into the thermally responsive resistor element a current which is responsive to the temperature of the environment detected by the thermally responsive resistor element and proportional to the instantaneous resistance of the thermally responsive resistor element, the current induced in the thermally responsive resistor element which is a function of temperature of the environment thus compensating for the deviation from a first order mathematical equation relating resistance and temperature which exists in the thermally responsive resistor element, the resultant current in the thermally responsive resistor element thus producing a voltage across the thermally responsive resistor element which varies substantially linearly with the temperature thereof, and means sensing the voltage across the thermally responsive resistor element.
Claim 15
Dependent Claim
166 words
Temperature responsive apparatus comprising in combination: a thermally responsive resistor element detecting the temperature of a given environment, the thermally responsive resistor element having a resistance characteristic which is non-linear with respect to temperature, means inducing directly into the thermally responsive resistor element a current of constant magnitude, means inducing directly into the thermally responsive resistor element a current which is responsive to the temperature of the environment detected by the thermally responsive resistor element and proportional to the instantaneous resistance of the thermally responsive resistor element, the current induced in the thermally responsive resistor element which is a function of temperature of the environment thus compensating for the deviation from a first order mathematical equation relating resistance and temperature which exists in the thermally responsive resistor element, the resultant current in the thermally responsive resistor element thus producing a voltage across the thermally responsive resistor element which varies substantially linearly with the temperature thereof, and means sensing the voltage across the thermally responsive resistor element.
Claim 16
Dependent Claim
102 words
Temperature responsive apparatus of claim 11 in which the thermally responsive resistor element is characterized substantially by the equation: T (RT - RO)/(R100-RO) 100 + k ( T )/(100 - 1) 100 + B (( T )/(100 - 1) ( T )3/(100),) wherein: T T in degrees C. RT resistance of thermometer at temperature T. RO resistance of thermometer at zero* C. R100 resistance of thermometer at 100* C. k a constant of thermometer at the boiling point of sulphur (444.6* C). B a constant based upon the boiling point of oxygen (-182.97* C) and the ice point of water (0* C).
Claim 17
Dependent Claim
46 words
The temperature responsive apparatus of claim 11 in which the thermally responsive resistor element is a resistance element provided with two current terminals and two voltage terminals, each current terminal being connected to a voltage terminal and each voltage terminal being connected to a current terminal.
Claim 18
Dependent Claim
33 words
The temperature responsive apparatus of claim 11 in which the means inducing in the thermally responsive resistance element a current which is a function of temperature of the environment includes an operational amplifier.
Claim 19
Dependent Claim
61 words
The temperature responsive apparatus of claim 11 which includes a first operational amplifier which generates the resultant current in the temperature detector means and a second operational amplifier which senses voltage across the temperature detector means, voltage sensing instrument means, means connecting the voltage sensing instrument means to the second operational amplifier and to the input of the first operational amplifier.
Claim 20
Dependent Claim
55 words
The temperature responsive apparatus of claim 11 in whicH both of said means inducing current in the temperature detector means include the same operational amplifier, a source of reference voltage of constant magnitude, voltage sensing instrument means, means connecting the voltage sensing instrument means to the operational amplifier and to the source of reference voltage.
Claim 21
Dependent Claim
74 words
The temperature responsive apparatus of claim 11 in which the means inducing in the thermally responsive resistance element a current which is a function of the temperature of the environment detected by the thermally responsive resistance element includes two operational amplifiers, one of the operational amplifiers being connected to provide current to the thermally responsive resistance element and the other operational amplifier being connected to sense the voltage across the thermally responsive resistance element.
Claim 22
Dependent Claim
46 words
The temperature responsive apparatus of claim 11 in which the means inducing in the thermally responsive resistance element a current of constant magnitude includes an operational amplifier having input terminal means and in which a source of constant signal is applied to the input terminal means.
Claim 23
Dependent Claim
40 words
The temperature responsive apparatus of claim 18 in which the operational amplifier has output terminal means and in which the thermally responsive resistance element is connected between the output terminal means and the input terminal means of the operational amplifier.
Claim 24
Dependent Claim
36 words
The temperature responsive apparatus of claim 19 in which the input terminal means includes a summing node and in which the thermally responsive resistance element is connected between the summing node and the output terminal means.
Claim 25
Dependent Claim
39 words
The temperature responsive apparatus of claim 18 which includes a point of zero signal and in which the thermally responsive resistance element is connected between the point of zero signal and the input terminal means of the operational amplifier.
Claim 26
Independent Claim
216 words
A method for obtaining over a limited temperature range an electrical output signal which is approximately linear with respect to temperature and which is substantially describable by a first order mathematical equation relating output signal and temperature obtained from an electrical resistance sensor device which has a characteristic of resistance versus temperature which departs from a straight line first order mathematical curve of resistance versus temperature by monotonically increasing amounts of resistance for temperatures which are increasingly removed from a temperature of absolute zero degrees, said method comprising the steps of: exciting only the electrical resistance sensor device with an electrical current having two components, the components being a first component which is constant and temperature independent in magnitude and a second component which is temperature dependent and of zero magnitude at some reference temperature located within the range of temperatures to be measured and of approximately linearly increasing magnitude with temperature at temperatures removed from the reference temperature, deriving the second component of current linearly from said electrical output signal which is approximately linear with respect to temperature, adjusting the amount of said second component to a value producing the minimum amount of difference over said limited temperature range between said electrical output signal and a signal which is ideally linear with respect to temperature.
Claim 27
Independent Claim
216 words
A method for obtaining over a limited temperature range an electrical output signal which is approximately linear with respect to temperature and which is substantially describable by a first order mathematical equation relating output signal and temperature obtained from an electrical resistance sensor device which has a characteristic of resistance versus temperature which departs from a straight line first order mathematical curve of resistance versus temperature by monotonically increasing amounts of resistance for temperatures which are increasingly removed from a temperature of absolute zero degrees, said method comprising the steps of: exciting only the electrical resistance sensor device with an electrical current having two components, the components being a first component which is constant and temperature independent in magnitude and a second component which is temperature dependent and of zero magnitude at some reference temperature located within the range of temperatures to be measured and of approximately linearly increasing magnitude with temperature at temperatures removed from the reference temperature, deriving the second component of current linearly from said electrical output signal which is approximately linear with respect to temperature, adjusting the amount of said second component to a value producing the minimum amount of difference over said limited temperature range between said electrical output signal and a signal which is ideally linear with respect to temperature.
Claim 28
Dependent Claim
337 words
Thermally responsive apparatus, comprising: a first operational amplifier device having a positive input terminal and a negative input terminal and an output terminal, a thermally responsive resistor device having a pair of current terminals at opposed ends thereof, and a pair of voltage terminals at opposed ends thereof, one of the current terminals being joined to the negative input terminal of the first operational amplifier and the other current terminal being joined to the output terminal of the operational amplifier, a common signal conductor, a temperature stable resistance member having an end joined to the negative input terminal of the first opera-tional amplifier, an opposite end of the temperature stable resistance member being joined to the common signal conductor, a source of temperature stable voltage having a given internal resistance and connected between the common signal conductor and the positive input terminal of the first operational amplifier, a second operational amplifier having a positive input terminal and a negative input terminal and an output terminal, a resistor having an end connected to the output terminal and an opposite end connected to the negative input terminal of the second operational amplifier, a resistance device having an adjustable tap between the ends thereof joined to the positive input terminal of the second operational amplifier, one end of the resistance device being connected to the common signal conductor and the other end of the resistance device being connected to one of the voltage terminals of the thermally responsive resistor, a resistor member having an end joined to the negative input terminal of the second operational amplifier and an end thereof connected to the other voltage terminal of the thermally responsive resistor device, a feedback resistance element having an end connected to the positive input terminal of the first operational am-plifier and an end connected to the output terminal of the second operational amplifier, a voltage sensing temperature indicator instrument connected to the output terminal of the second operational amplifier and to the positive input terminal of the first operational amplifier.
Claim 29
Dependent Claim
337 words
Thermally responsive apparatus, comprising: a first operational amplifier device having a positive input terminal and a negative input terminal and an output terminal, a thermally responsive resistor device having a pair of current terminals at opposed ends thereof, and a pair of voltage terminals at opposed ends thereof, one of the current terminals being joined to the negative input terminal of the first operational amplifier and the other current terminal being joined to the output terminal of the operational amplifier, a common signal conductor, a temperature stable resistance member having an end joined to the negative input terminal of the first opera-tional amplifier, an opposite end of the temperature stable resistance member being joined to the common signal conductor, a source of temperature stable voltage having a given internal resistance and connected between the common signal conductor and the positive input terminal of the first operational amplifier, a second operational amplifier having a positive input terminal and a negative input terminal and an output terminal, a resistor having an end connected to the output terminal and an opposite end connected to the negative input terminal of the second operational amplifier, a resistance device having an adjustable tap between the ends thereof joined to the positive input terminal of the second operational amplifier, one end of the resistance device being connected to the common signal conductor and the other end of the resistance device being connected to one of the voltage terminals of the thermally responsive resistor, a resistor member having an end joined to the negative input terminal of the second operational amplifier and an end thereof connected to the other voltage terminal of the thermally responsive resistor device, a feedback resistance element having an end connected to the positive input terminal of the first operational am-plifier and an end connected to the output terminal of the second operational amplifier, a voltage sensing temperature indicator instrument connected to the output terminal of the second operational amplifier and to the positive input terminal of the first operational amplifier.
Claim 30
Dependent Claim
36 words
The thermally responsive apparatus of claim 23 in which the resistance value of the temperature stable resistance member and the resistance value of the thermally responsive resistor device are substantially equal at a given reference temperature.
Claim 31
Dependent Claim
35 words
The thermally responsive apparatus of claim 23 in which the resistance value of the feedback resistance element is substantially 250 times the resistance value of the internal resistance of the source of temperature stable voltage.
Claim 32
Dependent Claim
166 words
Temperature responsive apparatus comprising in combination: temperature detector means detecting the temperature of a given environment, the temperature detector means having a resistance characteristic which is non-linear with respect to temperature, means inducing in the temperature detector means a current of constant magnitude, means inducing in the temperature detector means a current which is responsive to the temperature of the environment detected by the temperature detector means and proportional to the instantaneous resistance of the temperature detector means, the current induced in the temperature detector means which is a function of the temperature of the environment thus compensating for the deviation from a first order mathematical equation relating resistance and temperature which exists in the resistance detector means, the resultant current in the temperature detector means thus producing a voltage across the temperature detector means which varies substantially linearly with the temperature thereof, means sensing the voltage across the temperature detector means, the means sensing the voltage across the temperature detector means including an operational amplifier.
Claim 33
Dependent Claim
166 words
Temperature responsive apparatus comprising in combination: temperature detector means detecting the temperature of a given environment, the temperature detector means having a resistance characteristic which is non-linear with respect to temperature, means inducing in the temperature detector means a current of constant magnitude, means inducing in the temperature detector means a current which is responsive to the temperature of the environment detected by the temperature detector means and proportional to the instantaneous resistance of the temperature detector means, the current induced in the temperature detector means which is a function of the temperature of the environment thus compensating for the deviation from a first order mathematical equation relating resistance and temperature which exists in the resistance detector means, the resultant current in the temperature detector means thus producing a voltage across the temperature detector means which varies substantially linearly with the temperature thereof, means sensing the voltage across the temperature detector means, the means sensing the voltage across the temperature detector means including an operational amplifier.
Claim 34
Dependent Claim
18 words
The temperature responsive apparatus of claim 26 which includes a voltage sensing instrument joined to the operational amplifier.
Claim 35
Dependent Claim
31 words
The temperature responsive apparatus of claim 26 which includes a second operational amplifier and a digital voltmeter, the second operational amplifier joining the digital voltmeter to the first said operational amplifier.
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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) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |