Microdischarge detector method and apparatus
AssigneeHoneywell International Inc.
InventorsUlrich Bonne, Teresa M. Marta, Fouad Nusseibeh
Life of this patent
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Abstract
A differential microdischarge detector system. The system comprises two microdischarge detectors (MDDs). One of the MDDs is connected to receive sample analytes to be measured, while the other MDD is connected to receive a reference sample that contains interfering gases and none or a much lower concentration of the sample analytes to be measured. The outputs of the two MDD's are fed to a circuit that generates either a difference or a ratio between the measurements of the two MDDs. In addition, the current, impedance or voltage across the electrodes of the two MDDs may be measured and processed to generate either a difference or a ratio signal, thus obtaining additional information about the sample gas analytes.
Claims24
A microdischarge detection system comprising:
- a first microdischarge detector generating a first measurement signal;
- a second microdischarge detector generating a second measurement signal;
- and
- a circuit coupled to receive said first and second measurement signals and produce an output signal that is one of a difference between said first and second measurement signals and a ratio between said first and second measurement signals,
- wherein said circuit produces an output signal that is a ratio between said first and second measurement signals.
A gas chromatograph system comprising:
- a gas chromatograph having a carrier gas carrying a pulse of sample gas through a capillary that adsorbs and desorbs gasses passing therethrough;
- a bypass path through which passes said carrier gas either without said sample gas pulse or with said sample gas pulse in an unseparated and diluted form;
- a first microdischarge detector comprising a pair of electrodes defining a gap through which a current is made to pass, said first microdischarge detector coupled to an outlet of said capillary to receive gas that has flowed through said capillary and pass it through said gap so as to cause said gas passing through said gap to emit electromagnetic radiation, and further comprising a detector system for detecting the spectrum of said emitted electromagnetic radiation to generate a first measurement signal of said spectrum;
- a second microdischarge detector comprising a pair of electrodes defining a gap through which a current is made to pass, said second microdischarge detector coupled to an outlet of said bypass path to receive gas that has flowed through said bypass path and pass it through said gap so as to cause said gas passing through said gap to emit electromagnetic radiation, and further comprising a detector system for detecting the spectrum of said emitted electromagnetic radiation to generate a second measurement signal of said spectrum;
- a first differential circuit coupled to receive said first and second measurement signals and produce a differential spectral output signal;
- and
- a measurement system coupled to analyze said differential spectral output signal and determine physical properties of said sample gas pulse therefrom.
A method of measuring physical phenomena using a microdischarge detector comprising the steps of:
- obtaining a first measurement with a first microdischarge detector, said measurement including background noise;
- obtaining a second measurement of said background noise with a second microdischarge detector;
- and
- generating a differential measurement signal of said first and second measurements,
- wherein said generating step comprises determining a ratio between said second measurement signal and said first measurement signal.
A method of performing gas chromatography comprising the steps of:
- passing a sample gas carried in a carrier gas through a gas chromatograph capillary and into a first microdischarge detector;
- passing said carrier gas through a bypass conduit and into a second microdischarge detector;
- obtaining an emission spectrum measurement with said first microdischarge detector, said measurement including background noise;
- obtaining a second measurement of said background noise with said second microdischarge detector;
- generating a differential measurement signal of said first and second measurements;
- and
- analyzing said differential measurement signal to detect physical properties of said sample gas.
Dependencies are inferred from the claim text.