How Gas Purity mode works and its measurement accuracy
Gas Purity mode allows the He/O₂ analyzer to evaluate certain binary gas mixtures based on differences in the speed of sound. This article explains how the mode works and what accuracy can be expected.
How Gas Purity mode works
Gas Purity mode measures binary gas mixtures — two-component gas combinations — where the components have sufficiently different speeds of sound (VOS). Because it relies solely on acoustic measurement, this mode does not use the oxygen sensor.
For example, Gas Purity mode can detect argon contamination in air. In this case, air is modelled as a binary mixture of oxygen and nitrogen; any other gases present are excluded from the calculation. Note that this mode cannot measure oxygen concentration in air — use standard Trimix measurement for that purpose.
Measurement accuracy
Because some gases have similar speeds of sound, Gas Purity mode is inherently less accurate than standard Trimix measurement.
Typical Gas Purity mode accuracy:
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±1% at the low and high ends of the measurement range
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Up to ±3% in the middle of the range For best results, avoid operating in mid-range concentrations where accuracy requirements are tight. Refer to the device specifications for the full accuracy table.