The first choice: which operating principle?

If you are looking for reliable information, do not ask the sellers, but the users


– Because capillaries are static : probably they will not change their performances for years and are ready to provide the best results as soon as the gas pressure is applied.

– Because capillaries are not always a stupid element : joined to PID electronic pressures control and using advanced setpoint calculations, applied physics give the base for relationships where all the influencing elements are accounted.

– Because the sole influence by gas mixture depending element (the viscosity) is one of the more studied physical parameter, in Engineering (pressure drop in piping) and in Medical science (blood circulation). When known, using one of many empirical available formulas, his effects may be compensated, and we do it.

– Because pressure linear control is normal, but flow linearizing is a difficult task mainly when percent of flow range decrease … deviations measurements at low resolution give inaccurate corrections.

Because, using calculated pressures setpoints, capillaries are not just a step in step by step diluting tool, but also a guide line base to cover continuously the diluting space between the steps : do you want to get whichever gas concentration in a wide dilution range ? you can, also with capillaries, but you get it truly !

– Because capillaries are not just the mean to dilute 5 or 10 to 1 : you may have much more up to 0,008333% (it’s not a comma error : it’s 12.000 :1 !).