Gas analysis. Preparation of calibration gas mixtures using dynamic methods Critical flow orifices

Available format(s)

Hardcopy , PDF

Language(s)

English

Published date

04-09-2017

Publisher

British Standards Institution

This document specifies a method for the dynamic preparation of calibration gas mixtures containing at least two gases (usually one of them is a complementary gas) from pure gases or gas pre-mixtures using critical flow orifices systems.

The method applies principally to the preparation of mixtures of non-reactive gases that do not react with any of the materials forming the gas circuit inside the critical flow orifices system or auxiliary equipment. It has the merit of allowing multi-component mixtures to be prepared as readily as binary mixtures if an appropriate number of critical flow orifices are used.

By selecting appropriate combinations of critical flow orifices, a dilution ratio of 1×10⁴ is achievable.

Although it is more particularly applicable to the preparation of gas mixtures at atmospheric pressure, the method also offers the possibility of preparing calibration gas mixtures at pressures greater than atmospheric. The upstream pressure will need to be at least two times higher than downstream pressure.

The range of flow rates covered by this document extends from 1ml/min to 10l/min.

Committee	PTI/15
DevelopmentNote	Renumbers and supersedes BS ISO 6145-6. 2008 version incorporates corrigendum to BS ISO 6145-6. Supersedes BS 4559-5.6(1987) & 97/125573 DC. (02/2009) Supersedes 16/30266428 DC. (09/2017)
DocumentType	Standard
Pages	36
PublisherName	British Standards Institution
Status	Current
Supersedes	16/30266428 DC : DRAFT MAR 2016 BS ISO 6145-6 : 2003 BS EN ISO 6145-6:2008 97/125573 DC : DRAFT OCT 1997 BS 4559-5.6:1987

Standards	Relationship
EN ISO 6145-6:2017	Identical
ISO 6145-6:2017	Identical

ISO 12963:2017	Gas analysis — Comparison methods for the determination of the composition of gas mixtures based on one- and two-point calibration
ISO 9300:2005	Measurement of gas flow by means of critical flow Venturi nozzles
ISO 16664:2017	Gas analysis — Handling of calibration gases and gas mixtures — Guidelines
ISO 6143:2001	Gas analysis — Comparison methods for determining and checking the composition of calibration gas mixtures
ISO 19229:2015	Gas analysis Purity analysis and the treatment of purity data
ISO 14912:2003	Gas analysis — Conversion of gas mixture composition data
VDI 3490 Blatt 16:1994-10	Measurement of gases - Calibration gas mixtures - Dynamic preparation with critical orifice systems
ISO 7504:2015	Gas analysis Vocabulary
ISO/IEC Guide 98-3:2008	Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in measurement (GUM:1995)