Electricity: measuring and testing – Electrolyte properties – Using a conductivity determining device
Patent
1994-06-29
1996-04-02
Regan, Maura K.
Electricity: measuring and testing
Electrolyte properties
Using a conductivity determining device
324442, G01N 2702
Patent
active
055044301
ABSTRACT:
The present invention relates to a method for measuring conductivity, in particular for use in liquid chromatography systems, and to a device for performing such measurement. In one aspect it provides a method of measuring conductivity in liquids, comprising applying an AC voltage over a conductivity measurement cell. In response to a conductance value calculated from the output of the cell, an expected frequency of the AC voltage is generated. The AC voltage frequency is set to the calculated value. The above steps are repeated until two consecutive conductance determinations differ by only a predetermined absolute value. Then the value may be displayed and registered as the true conductance value of the sample. In another aspect it provides a device for measuring conductivity in liquids, comprising a conductivity measurement cell; AC voltage means for supplying a variable AC voltage across the cell; an operational amplifier having one input connected to the AC voltage means, and the other input to the cell; an AC/DC converter connected to the output of the operational amplifier; an A/D converter connected to the output of the AC/DC converter, the output of the A/D converter being connected to a computing unit; said computing unit comprising means for calculating a conductance value based on the output from said A/D converter; means for calculating an expected AC voltage frequency from said conductance value; means for comparing said calculated expected frequency value with the frequency of the AC voltage applied across the cell; means for altering the frequency of the AC voltage supply to equal a value corresponding to the calculated conductance value if there is a difference between them; means for repeating the calculating and comparing of frequency values until the difference between actual value and expected value is below a preset absolute value; and means for displaying the conductance value.
REFERENCES:
patent: 3213361 (1965-10-01), Dornberger et al.
patent: 3969669 (1976-07-01), Brault et al.
patent: 4160946 (1979-07-01), Frigato
patent: 4808930 (1989-02-01), Kaiser
patent: 5138264 (1992-08-01), Seki et al.
patent: 5334940 (1994-08-01), Blades
Jones et al. vol. 57 Journal of American Chemical Society Feb. 6, 1935.
Boukamp et al. Use of Low Frequency AC Measurements in Solid State Electrochemistry (From Conference) (May. 1979).
Journal of Physical Chemistry Oct. 1938 Acree et al.
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