Standard

ISO 6145-7:2009

Tilbaketrukket

Merknad: Denne standarden har en ny utgave: ISO 6145-7:2018

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Omfang

ISO 6145-7:2009 specifies a method for continuous production of calibration gas mixtures, containing two or more components, from pure gases or other gas mixtures by use of commercially available thermal mass-flow controllers. If this method is employed for the preparation of calibration gas mixtures, the optimum performance is as follows: the relative expanded uncertainty of measurement, U, obtained by multiplying the combined standard uncertainty by a coverage factor k = 2, is not greater than 2 %. If pre-mixed gases are used instead of pure gases, mole fractions below 10-6 can be obtained. The measurement of mass flow is not absolute and the flow controller requires independent calibration. The merits of the method are that a large quantity of the gas mixture can be prepared on a continuous basis and that multicomponent mixtures can be prepared as readily as binary mixtures if the appropriate number of thermal mass-flow controllers is utilized.

Dokumentinformasjon

  • Standard fra ISO
  • Publisert:
  • Tilbaketrukket:
  • products.specs.Expires:
  • Utgave: 2
  • Versjon: 1
  • Varetype: IS
  • ICS 71.040.40
  • ISO TC ISO/TC 158

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