Gas chromatograph with digital processing of a thermoconductivity detector signal
First Claim
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1. A gas chromatograph operable to analyze a sample gas comprising a carrier gas and components, the gas chromatograph comprising:
- a separation device operable to separate the components of the sample gas;
a sample sensor connected to an output of the separation device so as to be in contact with the sample gas, the sample sensor having a resistance that is dependent on the temperature of the sample sensor;
a bridge circuit into which the sample sensor is connected, the bridge circuit comprising a plurality of resistors;
a servo amplifier connected to the bridge circuit and operable to maintain the sample sensor at a constant temperature, the servo amplifier having an output corresponding to the thermal conductivity of the sample gas;
an analog-to-digital converter operable to generate a digitized sample signal from the output of the servo amplifier;
a processor connected to the analog-to-digital converter and operable to receive the digitized sample signal;
a computer readable medium; and
program instructions stored on the computer readable medium and executable by the processor to perform a method of quantifying the components in the sample gas solely from the digitized sample signal.
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Abstract
A gas chromatograph operable to analyze a sample gas comprising a carrier gas and components. The gas chromatograph includes a bridge circuit with a sample sensor connected therein. A servo amplifier is connected to the bridge circuit and is operable to maintain the sample sensor at a constant temperature. An output of the servo amplifier is digitized and is used to quantify the components in the sample gas.
71 Citations
14 Claims
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1. A gas chromatograph operable to analyze a sample gas comprising a carrier gas and components, the gas chromatograph comprising:
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a separation device operable to separate the components of the sample gas; a sample sensor connected to an output of the separation device so as to be in contact with the sample gas, the sample sensor having a resistance that is dependent on the temperature of the sample sensor; a bridge circuit into which the sample sensor is connected, the bridge circuit comprising a plurality of resistors; a servo amplifier connected to the bridge circuit and operable to maintain the sample sensor at a constant temperature, the servo amplifier having an output corresponding to the thermal conductivity of the sample gas; an analog-to-digital converter operable to generate a digitized sample signal from the output of the servo amplifier; a processor connected to the analog-to-digital converter and operable to receive the digitized sample signal; a computer readable medium; and program instructions stored on the computer readable medium and executable by the processor to perform a method of quantifying the components in the sample gas solely from the digitized sample signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification