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EVS-EN ISO 6145-7:2018

Gas analysis - Preparation of calibration gas mixtures using dynamic methods - Part 7: Thermal mass-flow controllers (ISO 6145-7:2018)

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Kehtiv alates 03.01.2019
Alusdokumendid
ISO 6145-7:2018; EN ISO 6145-7:2018
Tegevusala (ICS grupid)
71.040.40 Keemiline analüüs
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Standardi ajalugu
Staatus
Kuupäev
Tüüp
Nimetus
03.01.2019
Põhitekst
03.02.2011
Põhitekst
ISO 6145 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.
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EVS-EN ISO 6145-1:2008

Gas analysis - Preparation of calibration gas mixtures using dynamic volumetric methods - Part 1: Methods of calibration
Kehtetu alates 01.11.2019
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EVS-EN ISO 6145-10:2008

Gas analysis - Preparation of calibration gas mixtures using dynamic volumetric methods - Part 10: Permeation method
Uusim versioon Kehtiv alates 07.10.2008
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EVS-EN ISO 6143:2006

Gas analysis - Comparison methods for determining and checking the composition of calibration gas mixtures
Uusim versioon Kehtiv alates 06.10.2006