Metrology of excellence
The GasMix™ is Linear, Accurate and Repeatable
GasMix™ diluters are compliant with ISO 6145-7 “Gas analysis — Preparation of calibration gas mixtures using dynamic volumetric methods — Part 7: Thermal mass-flow controllers”. What does the norm say ?
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 “ISO 6145-7:2018 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 pre-mixed gases are used instead of pure gases, mole fractions below ppm can be obtained. The measurement of mass flow is not absolute and the flow controller requires independent calibration.”
GasMix™ products not only comply, but exceed the ISO 6145-7 requirements.
Every individual Mass Flow Controller (MFC) used in GasMix™ instrument undergoes a rigorous calibration at Alytech factory ensuring highest accuracy and linearity with particular attention to low end and high end of the range. Recording gas pressure and temperature, we perform 20 calibration points up and down of all scale with 10 repeats on each point that results in extremely robust and precise calibration curve of MFC for a specific gas. The procedure is repeated for every gas matrix on customer choice (He, Ar, CH4, H2, N2, Air, …). A Student test allows checking for reproducibility and hysteresis. Once accepted, relative uncertainty of the flow is fitted across the MFC range and stored in the GasMix software as a LUT (look-up-table) for every gas. Running a dilution/mixing sequence the system automatically calculates and report maximum uncertainty for any programmed flow.
Traceability
Factory calibration is made by a primary standard traceable to NIST. All factory quality control steps are documented and every instrument delivered with a detailed certificate.
An Audit Trail function, included in the software, guarantees the operation traceability, recording the actual flows sent to the analyzer and all event logs.
Following highest standards in metrology the GasMix™ is the only software on the market where relative uncertainty is calculated across the whole range of each MFC. It allows accurate predicting of maximum uncertainty for any produced gas concentration.