US3759083A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sensing element response time measuring system
Assignee: United States Atomic Energy Commission
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Filing: 1972-04-19
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Granted: 1973-09-18
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Expires: 1992-04-19
Abstract
Abstract A resistance temperature detector, which is one arm of a bridge circuit, is heated by an electric current separate from the bridge exciting current, to a temperature higher than its environmental temperature. The time required for the RTD to cool through a predetermined temperature range after the heating current is removed is measured to determine the response time of the RTD.
Inventors
- 👤 G Erickson
- 👤 D Jaszkowiak
- 👤 J Kaveckis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:40
CPC Classifications
G; G01; G01K; G01K15/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
354 words
A time response measuring device for a resistance temperature detector, said time response measuring device comprising, resistance measuring means coupled to the resistance temperature detector, said resistance measuring means being in the form of a bridge circuit with the resistance temperature detector as one of the bridge arms, said resistance measuring means including an exciting current supply coupled to said bridge circuit for providing an exciting signal thereto, said resistance measuring means further including means for balancing said bridge circuit whereby said resistance measuring means develops an output signal E1 0 with the resistance temperature detector at a first temperature, control means for developing a first time signal and a second time signal a predetermined time interval after said first time signal, self-heat current supply means coupled to said control means and to the resistance temperature detector for supplying a self-heat current thereto for said predetermined time interval in response to said first and second time signals with the frequency of said self-heat current being different from the frequency of said exciting signal, said self-heat current acting to increase the temperature of the resistance temperature detector to a second temperature whereby said resistance measuring means develops an output signal E2 at the end of said predetermined time interval, said temperature of the resistance temperature detector changing from said second temperature to said first temperature after said predetermined time interval, signal measuring means coupled to said resistance measuring means and said control means, said signal measuring means acting to measure Delta E E2 - E1, said resistance measuring means further acting to develop a varying output signal E3 as the temperature of the resistance temperature detector changes from said second temperature to said first temperature, said signal measuring means being responsive to E3 equal to a predetermined signal E4 to develop a third time signal where E4 is equal to E1 plus a predetermined percentage of Delta E, timing means coupled to said control means and said signal measuring means and responsive to said second and third time signals to measure the time intervAl therebetween to determine the time response of the resistance temperature detector.
Claim 2
Dependent Claim
354 words
A time response measuring device for a resistance temperature detector, said time response measuring device comprising, resistance measuring means coupled to the resistance temperature detector, said resistance measuring means being in the form of a bridge circuit with the resistance temperature detector as one of the bridge arms, said resistance measuring means including an exciting current supply coupled to said bridge circuit for providing an exciting signal thereto, said resistance measuring means further including means for balancing said bridge circuit whereby said resistance measuring means develops an output signal E1 0 with the resistance temperature detector at a first temperature, control means for developing a first time signal and a second time signal a predetermined time interval after said first time signal, self-heat current supply means coupled to said control means and to the resistance temperature detector for supplying a self-heat current thereto for said predetermined time interval in response to said first and second time signals with the frequency of said self-heat current being different from the frequency of said exciting signal, said self-heat current acting to increase the temperature of the resistance temperature detector to a second temperature whereby said resistance measuring means develops an output signal E2 at the end of said predetermined time interval, said temperature of the resistance temperature detector changing from said second temperature to said first temperature after said predetermined time interval, signal measuring means coupled to said resistance measuring means and said control means, said signal measuring means acting to measure Delta E E2 - E1, said resistance measuring means further acting to develop a varying output signal E3 as the temperature of the resistance temperature detector changes from said second temperature to said first temperature, said signal measuring means being responsive to E3 equal to a predetermined signal E4 to develop a third time signal where E4 is equal to E1 plus a predetermined percentage of Delta E, timing means coupled to said control means and said signal measuring means and responsive to said second and third time signals to measure the time intervAl therebetween to determine the time response of the resistance temperature detector.
Claim 3
Independent Claim
183 words
A method of measuring the response time of a resistance temperature detector including the steps of: a. establishing the resistance temperature detector at a first temperature and measuring the value of the resistance of said resistance temperature detector at said first temperature with a bridge circuit with the resistance temperature detector being one arm of said bridge circuit, said bridge circuit being excited by an AC signal, b. adding electric energy to said resistance temperature detector with a DC signal to increase the temperature thereof to a second temperature and measuring said value of resistance of said resistance temperature detector at said second temperature, c. stopping the addition of energy to the resistance temperature detector to permit the temperature thereof to change from said second temperature to said first temperature, and d. measuring the time required for said value of resistance of said resistance temperature detector to change a predetermined percentage of the difference between said value of resistance at said first temperature and said value of resistance at said second second temperature to measure the response time of said resistance temperature detector.
Claim 4
Independent Claim
183 words
A method of measuring the response time of a resistance temperature detector including the steps of: a. establishing the resistance temperature detector at a first temperature and measuring the value of the resistance of said resistance temperature detector at said first temperature with a bridge circuit with the resistance temperature detector being one arm of said bridge circuit, said bridge circuit being excited by an AC signal, b. adding electric energy to said resistance temperature detector with a DC signal to increase the temperature thereof to a second temperature and measuring said value of resistance of said resistance temperature detector at said second temperature, c. stopping the addition of energy to the resistance temperature detector to permit the temperature thereof to change from said second temperature to said first temperature, and d. measuring the time required for said value of resistance of said resistance temperature detector to change a predetermined percentage of the difference between said value of resistance at said first temperature and said value of resistance at said second second temperature to measure the response time of said resistance temperature detector.
Claim 5
Dependent Claim
20 words
The time response measuring device of claim 1 wherein, said exciting signal is AC and said self-heat current is DC.
Claim 6
Dependent Claim
88 words
The time response measuring device of claim 3 wherein, said signal measuring means includes a track and hold circuit for receiving and storing said output signal E2, said signal measuring means further having ratio network means coupled to said track and hold circuit and comparator means coupled to said signal measuring means and said ratio network means, said ratio network means acting to develop said signal E4 as a predetermined percentage of Delta E, said comparator means being responsive to E3 E4 to develop said third time signal.
Claim 7
Dependent Claim
29 words
The time response measuring device of claim 4 wherein, said timing means has a variable timing rate to compensate for heating the resistance temperature detector with said self-heat current.
Claim 8
Dependent Claim
111 words
The time response measuring device of claim 5 wherein, said second time signal has a first portion and a second portion which occurs after said first portion, said self-heat current supply means being responsive to said second portion of said second time signal to establish the end of said predetermined time interval and said signal measuring means being responsive to said first portion of said second time signal to establish the value E2, said resistance measuring means including filter means for separating said AC exciting signal from said DC self-heat current and AC to DC converting means for converting said AC exciting signal to DC whereby said output signals are DC.
Claim 9
Dependent Claim
20 words
The time response measuring device of claim 1 wherein, said exciting signal is DC and said self-heat current is AC.
References Cited (Backward Citations)
US3498128A
Cited
US3533273A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |