Patent US777048A successfully refreshed from Google Patents.
Patent US4119909A successfully refreshed from Google Patents.
US4119909A
Expired / Lapsed
US
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Pulsed DC transient conductivity measurement system
Assignee: Radian Corp
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Filing: 1977-03-31
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Granted: 1978-10-10
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Expires: 1997-03-31
Abstract
Abstract Methods and apparatus are disclosed herein for measuring the electrical conductivity of unknown fluid solutions. A constant current DC pulse having a very fast rise time is supplied to a test cell containing the unknown solution. By sampling the voltage across the test cell just prior to the application of the pulse and at a predetermined time during the application of the constant current pulse, a voltage difference is obtained which may be interpreted in terms of the conductivity of the unknown solution.
Inventors
- 👤 David W. DeBerry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:14
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/06; G01R; G01R27/00; G01R27/02; G01R27/22
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
129 words
A method of measuring representations of the electrical conductivity of a fluid solution, comprising the steps of: locating a sample of fluid to be measured between a pair of measurement electrodes; sampling the zero current voltage drop between said measurement electrodes, generating a signal representative thereof and storing said representative signal; applying a very fast rise time DC constant current pulse to said measurement electrodes; sampling, at a predetermined time interval from the beginning of the application of said DC pulse, the constant current voltage drop between said electrodes and generating a signal representative thereof; and forming a difference function of said zero current voltage drop and said constant current voltage drop signals to generate a measurement signal representative of the electrical conductivity of a fluid to be measured.
Claim 2
Independent Claim
129 words
A method of measuring representations of the electrical conductivity of a fluid solution, comprising the steps of: locating a sample of fluid to be measured between a pair of measurement electrodes; sampling the zero current voltage drop between said measurement electrodes, generating a signal representative thereof and storing said representative signal; applying a very fast rise time DC constant current pulse to said measurement electrodes; sampling, at a predetermined time interval from the beginning of the application of said DC pulse, the constant current voltage drop between said electrodes and generating a signal representative thereof; and forming a difference function of said zero current voltage drop and said constant current voltage drop signals to generate a measurement signal representative of the electrical conductivity of a fluid to be measured.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein said predetermined time interval from the beginning of the application of said DC pulse is about 10 microseconds.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein said sampling steps are performed by sample and hold circuits.
Claim 5
Dependent Claim
17 words
The method of claim 1 wherein said constant current DC pulse is of predetermined selectable current magnitude.
Claim 6
Dependent Claim
39 words
The method of claim 1 and further including the steps of: correcting said measurement signal for cell and circuit constants of the measurement apparatus to thereby provide an absolute measurement of the conductivity of a fluid to be measured.
Claim 7
Independent Claim
140 words
A system for measuring representations of the electrical conductivity of a fluid solution, comprising: a sample cell having a pair of measurement electrodes, for containing a fluid to be measured; means for sampling the zero current voltage drop between said measurement electrodes and for generating a signal representative thereof and for storing said representative signal; means for applying a very fast rise time constant current DC pulse to said measurement electrodes; means for sampling, at a predetermined time interval from the beginning of the application of said DC pulse, the constant current voltage drop between said electrodes and for generating a signal representative thereof; and means for forming a difference function of said zero current voltage drop and said constant current voltage drop signals to generate a measurement signal representative of the electrical conductivity of a fluid to be measured.
Claim 8
Independent Claim
140 words
A system for measuring representations of the electrical conductivity of a fluid solution, comprising: a sample cell having a pair of measurement electrodes, for containing a fluid to be measured; means for sampling the zero current voltage drop between said measurement electrodes and for generating a signal representative thereof and for storing said representative signal; means for applying a very fast rise time constant current DC pulse to said measurement electrodes; means for sampling, at a predetermined time interval from the beginning of the application of said DC pulse, the constant current voltage drop between said electrodes and for generating a signal representative thereof; and means for forming a difference function of said zero current voltage drop and said constant current voltage drop signals to generate a measurement signal representative of the electrical conductivity of a fluid to be measured.
Claim 9
Dependent Claim
15 words
The system of claim 6 wherein said measurement electrodes comprise a pair of platinum electrodes.
Claim 10
Dependent Claim
16 words
The system of claim 6 wherein said measurement electrodes comprise a pair of platinized platinum electrodes.
Claim 11
Dependent Claim
26 words
The system of claim 8 wherein said measurement electrodes have a surface area of approximately 1.5 cm 2 each and are located approximately 6.4 cm. apart.
Claim 12
Dependent Claim
17 words
The system of claim 6 wherein said sampling means comprise first and second sample and hold circuits.
Claim 13
Dependent Claim
13 words
The system of claim 10 wherein said differencing means comprises a subtraction circuit.
Claim 14
Dependent Claim
27 words
The system of claim 6 wherein said sample cell is open ended and means are provided for moving said fluid to be measured continuously through said cell.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-09 | 1982-04-10 | 1982-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-09 | 1986-04-10 | 1986-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-09 | 1990-04-10 | 1990-10-10 | $7700.00 | Window Closed / Lapsed |