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BS EN ISO 6145-7:2018

Current

Current

The latest, up-to-date edition.

Gas analysis. Preparation of calibration gas mixtures using dynamic methods Thermal mass-flow controllers

Available format(s)

Hardcopy , PDF

Language(s)

English

Published date

04-01-2019

€156.59
Excluding VAT

Committee
PTI/15
DocumentType
Standard
ISBN
9780580511707
Pages
22
PublisherName
British Standards Institution
Status
Current
Supersedes

ISO6145 is a series of documents dealing with various dynamic methods used for the preparation of calibration gas mixtures. This document specifies a method for continuous preparation of calibration gas mixtures, from nominally pure gases or gas mixtures by use of thermal mass-flow controllers. The method is applicable to preparation of mixtures of non-reacting species, i.e. those which do not react with any material of construction of the flow path in the thermal mass-flow controller or the ancillary equipment.

If this method is employed for preparation of calibration gas mixtures the optimum performance is as follows: the relative expanded measurement uncertainty U, obtained by multiplying the 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 calibration gas mixture can be prepared on a continuous basis and that multi-component mixtures can be prepared as readily as binary mixtures if the appropriate number of thermal mass-flow controllers is utilized.

NOTE Gas blending systems, based upon thermal mass-flow controllers, and some including the facility of computerization and automatic control, are commercially available.

Standards Relationship
EN ISO 6145-7:2010 Identical
EN ISO 6145-7:2018 Identical
ISO 6145-7:2018 Identical

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