Comparator apparatus and process
First Claim
Patent Images
1. Apparatus comprising:
- column means for chromatographically separating sample constituents to produce an eluate stream;
means for passing a first carrier fluid stream to the column means;
means for injecting sample constituents into the first carrier fluid stream being passed to the column means;
dielectric constant detector means including sample cell means having a first capacitance representative of a fluid passing therethrough and reference cell means having a second capacitance representative of a fluid passing therethrough;
means for passing the eluate stream through the sample cell means;
means for passing a second carrier fluid stream to the reference cell means;
first oscillator means comprising said sample cell means for producing a first frequency representative of the first capacitance;
second oscillator means comprising said reference cell means for producing a second frequency representative of the second capacitance;
means for combining the first frequency and the second frequency to produce an analysis frequency; and
comparator means for determining a threshold frequency and for producing a sensible signal representative of a difference between the threshold frequency and the analysis frequency.
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Abstract
Comparator apparatus and method produce a signal representative of the relationship between two signals. In a further aspect, the comparator apparatus and method are used to provide a calibration and status monitor for a chromatographic analyzer.
17 Citations
23 Claims
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1. Apparatus comprising:
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column means for chromatographically separating sample constituents to produce an eluate stream; means for passing a first carrier fluid stream to the column means; means for injecting sample constituents into the first carrier fluid stream being passed to the column means; dielectric constant detector means including sample cell means having a first capacitance representative of a fluid passing therethrough and reference cell means having a second capacitance representative of a fluid passing therethrough; means for passing the eluate stream through the sample cell means; means for passing a second carrier fluid stream to the reference cell means; first oscillator means comprising said sample cell means for producing a first frequency representative of the first capacitance; second oscillator means comprising said reference cell means for producing a second frequency representative of the second capacitance; means for combining the first frequency and the second frequency to produce an analysis frequency; and comparator means for determining a threshold frequency and for producing a sensible signal representative of a difference between the threshold frequency and the analysis frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. Apparatus comprising:
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column means for chromatographically separating sample constituents to produce an eluate stream; means for passing a first carrier fluid stream to the column means; means for injecting sample constituents into the first carrier fluid stream being passed to the column means; dielectric constant detector means including sample cell means having a first capacitance representative of a fluid passing therethrough and reference cell means having a second capacitance representative of a fluid passing therethrough; means for passing the eluate stream through the sample cell means; means for passing a second carrier fluid stream to the reference cell means; first oscillator means comprising said sample cell means for producing a first frequency representative of the first capacitance; second oscillator means comprising said reference cell means for producing a second frequency representative of the second capacitance; means for combining the first frequency and the second frequency to produce an analysis frequency; and comparator means for determining a threshold frequency and for producing a sensible signal representative of a difference between the threshold frequency and the analysis frequency said comparator means comprising; pulse generating means having an analysis frequency input, a timing circuit input, and a pulse output, and operable for producing a pulse at the pulse output responsive to an edge of an input pulse at the analysis frequency input, the pulse having a duration determined by a pulse width signal appearing at the timing circuit input; first means for electrically connecting the analysis frequency to the analysis frequency input of the pulse generating means; timing circuit means for determining a threshold frequency and for producing a pulse width signal output responsive to an input pulse at the analysis frequency input; second means for electrically connecting the timing circuit means output to the timing circuit input of the pulse generating means; and sensible signal means connected to the pulse output of the pulse generating means for producing a sensible signal representative of the difference between the threshold frequency and the analysis frequency. - View Dependent Claims (17, 18)
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19. Method comprising:
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passing a first stream through a chromatographic column to produce an eluate stream; passing the eluate stream through a first dielectric constant detector cell to produce a first capacitance representative of the eluate stream; passing a second stream through a second dielectric constant detector cell to produce a second capacitance representative of the thus passed through second stream; generating a first signal representative of the first capacitance; generating a second signal representative of the second capacitance; generating an analysis frequency representative of the difference between the first signal and the second signal; and generating a sensible signal representative of the difference between a threshold frequency and the analysis frequency. - View Dependent Claims (20, 21, 22, 23)
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Specification