Nova Patents
EP0745846A2

Improved pulsed discharge systems

Abstract

The discharge systems of this disclosure are useful in the chemical analysis field, including identification and quantification of gaseous impurities. The systems utilize a pair of electrodes which apply a spark across a gap between the electrodes, the spark preferably being repetitively formed. As an inert gas flows between the electrodes, the spark creates photons of energy which are emitted and are used as described. In alternate aspects, other particles are energized in the spark gap and subsequently surrender their energy. Photon emission or loss of energy assists in identification and measurement of peaks eluted from a typical gas chromatograph. The preferred inert gas is helium with or without traces of rare inert gases. <IMAGE>

EP0745846A2, drawing sheet 1
Sheet 1 of 29

Term

Term ended

Projected expiry passed 3 January 2015, 11.7 years ago.

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10 claims: 4 independent, 6 dependent

  1. 1
    A detector to analyze a sample compound comprising a closed chamber (221) having a helium flow inlet (218) and an outlet (236) spaced from the inlet to enable helium to flow through the chamber, electrodes (231, 232) which are spaced apart and means (243) to provide said electrodes with a current forming a spark sufficient to arc thereacross, said electrodes being positioned in said chamber to form a spark gap across helium flow through said chamber, means (235) downstream in said chamber from said spark-forming electrodes to inject the sample compound into the chamber, an output electrode in said chamber for collection of current formed as a result of the spark across the gap wherein the helium flows toward said output electrode to enable a current to be formed indicative of the concentration of the sample compound in said chamber, and the output electrode is connected to detector means (228) to measure the concentration of the sample in said chamber by changing current flow,    characterised in that a gas source is connected to the chamber to supply a dopant gas to said chamber from a gas source and the dopant is selected from neon, argon, krypton and xenon.
  2. 5
    A method of analysing a sample compound in a carrier gas comprising the steps of creating a flow of carrier gas through a chamber for exposure to DC current across the chamber, energising at least one component of said carrier gas to an excited state as a result of exposure to said DC current, subsequently commingling a gaseous sample flow compound with said carrier gas, forming charged particles in the gaseous sample as a result of ionizing radiation emitted in the decay of said excited component of said carrier gas wherein the charged particles are formed from said gaseous sample, measuring said charged particles and selectively identifying components of said sample compound utilising said measurements, characterised in that the carrier gas comprises a mixture of an inert gas and a dopant selected from the group comprising neon, argon, krypton and xenon, the DC current energising the inert gas to an excited metastable state, the dopant being energised to an excited state as a result of the decay of said metastable inert gas, and the charged particles formed as a result of ionising radiation emitted by the decay of said energised dopant component of said carrier gas in said chamber, said dopant being selected to selectively ionise components of said sample compound.
  3. 9
    A detector characterised in that said detector comprises a closed source chamber (712) filled with a source gas, a sample chamber with an inlet port (726) through which sample gas flows into the sample chamber and an outlet port (728) through which sample gas flows out of the sample chamber, two electrodes (714, 716) spaced apart in said source chamber to define a spark gap for high voltage DC current to thereby raise at least one component of said source gas to an excited state, a membrane window (740) separating said source chamber and said sample chamber through which ionising radiation, resulting from the decay of at least one said excited component of said source gas, passes from said source chamber to said sample chamber, means (730, 732) for detecting charged particles formed in said sample gas resulting from the exposure of said sample gas to said ionising radiation generated in said source chamber and passed through said membrane window into said sample chamber, means (738) for controlling the DC current and said charged particle detection, and means for converting said detected charged particles to corresponding measures of concentrations of compounds within said sample gas.
  4. 10
    A method of analysing a sample gas characterised in that the method comprises the steps of exposing a source gas in a closed source chamber (712) to DC current across the chamber, energising at least one component of said source gas to an excited state as a result of exposure to said DC current, exposing a sample gas in a sample chamber to ionising radiation resulting from the decay of at least one component of said source gas raised to an excited state as a result of exposure to said DC current which ionising radiation is directed through a membrane window separating said source chamber (712) and said sample chamber, forming charged particles in said sample gas as a result of said exposure to said ionising radiation, and measuring said charged particles wherein said measurement occurs in timed relationship to charged particle formation, and selectively determining concentrations of compounds contained in said sample gas by utilising said measurements.
Independent claims4