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Method and device for controlling flow rate of carrier gas in chromatographic apparatus

  • US 5,859,360 A
  • Filed: 05/15/1996
  • Issued: 01/12/1999
  • Est. Priority Date: 09/16/1994
  • Status: Expired due to Term
First Claim
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1. A method for controlling carrier gas flow rate through a gas chromatographic apparatus with capillary column subjected to temperature variations, by controlling the carrier gas feed pressure following computerized processing of equation (1) of carrier gas flow variation as a function of carrier gas pressure, of chromatographic column temperature, of system structural parameters and of gas parameters, said equation (1) is ##EQU13## wherein FoT is carrier flow rate at, pi is inlet carrier gas pressure, po is carrier gas outlet pressure, L is the length of the capillary column, η

  • is viscosity of the carrier gas, and d is inner diameter of the capillary tube, said method comprising;

    preliminarily passing a carrier gas through the apparatus, detecting pressure values, temperature and flow under stabilized conditions;

    preliminarily calculating a constant K1 representing the system structural parameters based on the values detected and on said equation (1), said constant K1 is ##EQU14## applying said constant K1 in said equation (1) for controlling carrier gas flow rate through calculation; and

    adjusting said carrier gas feed pressure thereby affecting the carrier gas flow rate while said gas chromatographic apparatus is being utilized.

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