UNE-EN ISO 6145-7:2020
Current
The latest, up-to-date edition.
Gas analysis - Preparation of calibration gas mixtures using dynamic methods - Part 7: Thermal mass-flow controllers (ISO 6145-7:2018)
Hardcopy , PDF
Spanish, Castilian, English
06-05-2020
ISO 6145 is a series of International Standards dealing with various dynamic methods used for the preparation of calibration gas mixtures. This part 7 specifies a method for continuous preparation of calibration gas mixtures, from pure gases or other gas mixtures by use of thermal mass-flow controllers.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 utilised.NOTE Gas blending systems, based upon thermal mass-flow controllers, and some including the facility of computerization and automatic control, are commercially available.
| Committee |
CTN 77/SC 2
|
| DocumentType |
Standard
|
| Pages |
24
|
| PublisherName |
Asociación Española de Normalización
|
| Status |
Current
|
| Standards | Relationship |
| EN ISO 6145-7:2018 | Identical |
| ISO 6145-7:2018 | Identical |
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