Standard Swedish standard · SS-EN ISO 6145-7:2011

Gas analysis - Preparation of calibration gas mixtures using dynamic volumetric methods - Part 7: Thermal mass-flow controllers (ISO 6145-7:2009)

Status: Withdrawn

· Replaced by: SS-EN ISO 6145-7:2019
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Standard Swedish standard · SS-EN ISO 6145-7:2011

Gas analysis - Preparation of calibration gas mixtures using dynamic volumetric methods - Part 7: Thermal mass-flow controllers (ISO 6145-7:2009)
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Scope
This part of ISO 6145 is one of a series of International Standards dealing with dynamic volumetric methods used for the preparation of calibration gas mixtures. This part specifies a method for continuous production of calibration gas mixtures, containing two or more components, from pure gases or other gas mixtures by use of commercially available thermal mass-flow controllers. If this method is employed for the preparation of calibration gas mixtures, the optimum performance is as follows: the relative expanded uncertainty of measurement, U, obtained by multiplying the combined 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 gas mixture can be prepared on a continuous basis and that multicomponent 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, some including the facility of computerization and automatic control, are commercially available.

Subjects

Chemical analysis (71.040.40)


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Standard Swedish standard · SS-EN ISO 6145-7:2011

Gas analysis - Preparation of calibration gas mixtures using dynamic volumetric methods - Part 7: Thermal mass-flow controllers (ISO 6145-7:2009)
Subscribe on standards - Read more Dölj
Price: 1 013 SEK
standard ikon pdf

PDF

Price: 1 013 SEK
standard ikon

Paper

Price: 1 620,80 SEK
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Product information

Language: English

Written by: Svenska institutet för standarder

International title:

Article no: STD-76328

Edition: 1

Approved: 1/13/2011

No of pages: 28

Replaced by: SS-EN ISO 6145-7:2019