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Norm

ISO 6145-6:2003

Issue date: 2003 05 08

Gas analysis — Preparation of calibration gas mixtures using dynamic volumetric methods — Part 6: Critical orifices

ISO 6145-6:2003 specifies a method for the continuous production of calibration gas mixtures, containing two or more components, from pure gases or other gas mixtures by ...
Withdrawn: 2017 07 11
Publisher:
International Organization for Standardization
Format:
Digital | 11 Pages
Language:
English
Currently valid:

ISO 6145-6:2003 specifies a method for the continuous production of calibration gas mixtures, containing two or more components, from pure gases or other gas mixtures by use of critical orifice systems. By selection of appropriate combinations of orifices and with the use of pure gases, the volume fraction of the calibration component in the calibration gas mixture can be varied by a factor of 104. Additionally, it can be changed by a factor of 102 by changing the initial pressures in the orifice systems. The uncertainty of the method depends mainly upon the flow calibration method and the variations in temperature and outlet pressure. The relative expanded uncertainty in the volume fraction obtainable for a binary mixture (at a coverage factor of 2) is 3 %.

If pre-mixed gases are used instead of pure gases, much lower volume fractions can be obtained. The mass flow rates or volume flow rates, from which the mass or volume fractions are determined, can be calculated and can be independently measured by a suitable method given in ISO 6145-1.

The merits of the method are that multi-component mixtures can be prepared as readily as binary mixtures if the appropriate number of orifices is utilized, and that a large quantity of calibration gas mixture can be prepared on a continuous basis. The range of flow rates can be from several millilitres per minute to approximately 10 l/min.

Although particularly applicable to preparation of gas mixtures at barometric pressure, the method also provides a means of preparation of calibration gas mixtures at pressures above barometric pressure.

ISO 6145-6:2017
2017 07 11
Gas analysis — Preparation of calibration gas mixtures using dynamic methods — Part 6: Critical flo...
Norm
ISO 6145-6:2003
2003 05 08
Gas analysis — Preparation of calibration gas mixtures using dynamic volumetric methods — Part 6: Cr...
Norm
ISO 6145-6:1986
1986 10 09
Gas analysis — Preparation of calibration gas mixtures — Dynamic volumetric methods — Part 6: Sonic ...
Norm
Norm
ISO 6145-6:2017
Issue date : 2017 07 11
Gas analysis — Preparation of calibration gas mixtures using dynamic methods — Part 6: Critical flow orifices