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ISO 6145-7:2009
© ISO 2024
ISO 6145-7:2009
Gas analysis — Preparation of calibration gas mixtures using dynamic volumetric methods — Part 7: Thermal mass-flow controllers
Версия 2
2009-04
В время отменен
Отозвано (Версия 2, 2009)

Тезис

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.

Общая информация

  • Текущий статус
     : Отозвано
    Дата публикации
     : 2009-04
    Этап
    : Отмена международного стандарта [95.99]
  • Версия
     : 2
  • Технический комитет :
    ISO/TC 158
    ICS :
    71.040.40 
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