Patent US5406829A successfully refreshed from Google Patents.
US5406829A
Expired / Lapsed
US
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Temperature control for chemical sensors
Assignee: St Clair Intellectual Property Consultants Inc
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Filing: 1994-04-19
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Granted: 1995-04-18
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Expires: 2014-04-19
Abstract
Abstract A temperature control system for acoustic wave chemical sensors monitors the frequency output from a reference sensor packaged within a heat conductive case with a test sensor. Since the frequency output fluctuates as a function of temperature, variations in frequency from a nominal value representing a desired steady state temperature for the sensors are detected and used as a control signal for a heating element attached to the heat conductive case.
Inventors
- 👤 Mihir K. Ravel
- 👤 Steven H. Pepper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:46
CPC Classifications
G; G05; G05D; G05D23/00; G05D23/19; G05D23/20; G05D23/1927; G05D23/1928
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
134 words
A system comprising: a chemical sensor package having a pair of temperature sensitive chemical sensors in a common temperature environment, a fluid containing an analyte chemical to be measured flowing across one of the sensors as a test sensor, the other sensor being a reference sensor isolated from the fluid flow, each sensor providing a frequency signal as an output; means for determining a difference in frequency between the outputs of the sensors, the difference in frequency being a measure of the amount of the analyte chemical in the fluid; means for heating the common temperature environment in response to a control signal; and means for generating the control signal as a function of the frequency signal from the reference sensor to maintain the temperature of the sensors at a desired steady state value.
Claim 2
Independent Claim
134 words
A system comprising: a chemical sensor package having a pair of temperature sensitive chemical sensors in a common temperature environment, a fluid containing an analyte chemical to be measured flowing across one of the sensors as a test sensor, the other sensor being a reference sensor isolated from the fluid flow, each sensor providing a frequency signal as an output; means for determining a difference in frequency between the outputs of the sensors, the difference in frequency being a measure of the amount of the analyte chemical in the fluid; means for heating the common temperature environment in response to a control signal; and means for generating the control signal as a function of the frequency signal from the reference sensor to maintain the temperature of the sensors at a desired steady state value.
Claim 3
Dependent Claim
45 words
The system as recited in claim 1 wherein the generating means comprises: means for determining a frequency value for the frequency signal from the reference sensor, the frequency value being a function of temperature; and means for converting the frequency value into the control signal.
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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) | 1998-04-17 | 1998-10-17 | 1999-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-04-17 | 2002-10-17 | 2003-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-04-17 | 2006-10-17 | 2007-04-18 | $7700.00 | Window Closed / Lapsed |