US4482967A
Expired / Lapsed
US
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Conductivity detector and method
Assignee: Dionex Corp
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Filing: 1981-09-18
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Granted: 1984-11-13
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Expires: 2001-09-18
Abstract
Abstract Disclosed is a conductivity detector for use in chromatography systems. The improved conductivity detector provides digital processing of a conductivity signal to provide improved stability. The detector compares a trial offset signal with a detected conductivity signal and when the compared values are within a predetermined value the detector processes the compared value and the final offset value thereby providing improved accuracy with higher resolution.
Inventors
- 👤 Barton Evans, Jr.
- 👤 James B. Stolz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:24
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/06; G01N30/00; G01N30/02; G01N30/62; G01N30/64; G01N2030/645
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
78 words
An ionic conductivity detector comprising, means for generating a first signal representing the ionic conductivity of a solution in a conductivity cell, means for generating an offset signal which is applied to said first signal to generate a second signal, said second signal being maintained below a predetermined value by incrementing the offset signal, and means for digitally processing said offset signal and said second signal to generate a third signal representing the measured value of said conductivity.
Claim 2
Dependent Claim
78 words
An ionic conductivity detector comprising, means for generating a first signal representing the ionic conductivity of a solution in a conductivity cell, means for generating an offset signal which is applied to said first signal to generate a second signal, said second signal being maintained below a predetermined value by incrementing the offset signal, and means for digitally processing said offset signal and said second signal to generate a third signal representing the measured value of said conductivity.
Claim 3
Dependent Claim
52 words
A detector as in claim 1 wherein said processing means include means for generating said offset signal having an initial value, means for comparing the difference between said first and offset signals with a predetermined value, means for incrementing said offset signal if the compared signal is less than a predetermined value.
Claim 4
Dependent Claim
13 words
A detector as in claim 1 including means for displaying said measured value.
Claim 5
Dependent Claim
24 words
A detector as in claim 1 wherein said processing means include means for correcting said measured conductivity to conductivity corresponding to a predetermined temperature.
Claim 6
Dependent Claim
19 words
A detector as in claim 1 wherein said processing means include means for measuring the temperature of said solution.
Claim 7
Dependent Claim
21 words
A detector as in claim 5 wherein said processing means include means for processing the calculated temperature with predetermined temperature coefficients.
Claim 8
Dependent Claim
78 words
In an ionic conductivity detector the method comprising the steps of generating a first signal representing the ionic conductivity of a solution in a conductivity cell, generating an offset signal which is applied to said first signal to generate a second signal, said second signal being maintained below a predetermined value by incrementing the offset signal, and digitally processing said offset signal and said second signal to generate a third signal representing the measured value of said conductivity.
Claim 9
Dependent Claim
78 words
In an ionic conductivity detector the method comprising the steps of generating a first signal representing the ionic conductivity of a solution in a conductivity cell, generating an offset signal which is applied to said first signal to generate a second signal, said second signal being maintained below a predetermined value by incrementing the offset signal, and digitally processing said offset signal and said second signal to generate a third signal representing the measured value of said conductivity.
Claim 10
Dependent Claim
24 words
An ionic conductivity detector as in claim 1 wherein said means for generating a first signal include a fixed amplitude variable frequency bipolar-pulse source.
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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) | 1987-11-13 | 1988-05-14 | 1988-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-13 | 1992-05-14 | 1992-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-13 | 1996-05-14 | 1996-11-13 | $7700.00 | Window Closed / Lapsed |