US5406829A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature control for chemical sensors
Assignee: St Clair Intellectual Property Consultants Inc
•
Filing: 1994-04-19
•
Granted: 1995-04-18
•
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 21:30
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.
References Cited (Backward Citations)
US3164004A
Cited
US3879992A
Cited
US3756068A
Cited
US3848457A
Cited
US3895912A
Cited
US4258563A
Cited
US4312228A
Cited
US4399686A
Cited
US4498330A
Cited
US4503703A
Cited
US4533520A
Cited
US4730478A
Cited
US4860573A
Cited
US4759210A
Cited
US5012668A
Cited
US5042288A
Cited
US5149197A
Cited
US5289715A
Cited
US5323636A
Cited
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 |