Effects due to the gas nature Excluding gas flow measuring techniques based on batch volumes mixtures, that are not suitable for producing dynamic gas diluters, and also dilution systems based on pumps and gears, which are non common in the world, all the other techniques are sensitive in different ways, to the chemical composition of gases and mistures used in the dilution process.  The effects due to chemical composition of gases and mixtures involved in dilution can lead to deviations much higher than those due to dimensional or external factors. To correct chemical influences, two ways are open : the experimental way, consisting in evaluating the compared response to the specific mixture with a known response and the theoretical way, using the “gas correction Factors GCF. The second one, requiring less work, is the widely most practiced. Unfortunately the declared deviations are in the order of ±5%,may be more. The…

Gas diluters and metrology It’s evident that, due to the type of service (quality test on gas analyzers) gas dividers belong to the metrology world.  It’s also evident that gas dividers outlet is not a measurement : they go through two flow measuring, but at the end the output value, the dilution ratio, is just a number : the ratio between two flows. It exists at least another “tool” with the same type of performances : the piece counting scale.  In this case two weigth measurements are done (the reference with one or few peaces and the counting hopper with the peaces to be counted). It translates the weigths ratio in the pieces number ratio and then the count. Two so special devices should receive a special threatment : in the counting tool, everybody expects that the reference for counting is one or some peaces of the same…