BS EN ISO 6145-6:2008 Gas analysis. Preparation of calibration gas mixtures using dynamic volumetric methods. Critical orifices.
BS EN ISO 6145-6 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.
BS EN ISO 6145-6 also provides methods by which the volume fraction of the calibration component in the calibration gas mixture can be varied.
The merits of BS EN ISO 6145-6 are that multi-component mixtures can be prepared as readily as binary mixtures. Also, the range of flow rates can be from several millilitres per minute to approximately 10 l/min.
BS EN ISO 6145-6 applies to the preparation of gas mixtures at barometric pressure. It also provides a means of preparation of calibration gas mixtures at pressures above barometric pressure.
BS EN ISO 6145-6 also gives practical hints on the use of this method.
Contents of BS EN ISO 6145-6:
Scope
Normative references
Principle
Application to preparation of gas mixtures
Description of the orifice system and the experimental procedure
Area of validity
Operating conditions
Calculation of operating parameters and results
Selection of suitable orifice systems
Calculation of volume fraction
Sources of uncertainty
Uncertainty of volume fraction
Premixed gases for preparation of mixtures of high dilution
Practical hints
Bibliography
