| 摘要 |
<p>System for dynamically generating a low concentration calibration gas mixture (254) from a high concentration gas and a high purity diluent comprises, in a purged enclosure (212), calibrating gas containing vessels (256,298,274), a series of parallel calibrating gas conduits (262,302,285) controlled by mass flow controllers (260,300,284) for selectively connecting said vessels (256,298,274) to a controlled source (226) of diluent gas, and valved conduits (246,292,268) to purge said conduits of residual analyte with diluent through respective vent means.</p> |
