| 摘要 |
A capillary sampling flow controller provides an improvement in the process of sampling or monitoring for the analysis of air and gas chemistries; a constant flow rate is used to introduce a specific volume of gas into a vessel or through a trapping media over the selected sampling period. The improvement employs calculated geometry of the capillaries employed to deliver the gas sample to the evacuated vessel. It can also include a pressure reading device installed between the vessel and the capillary, and a filter at the inlet. The length of capillary with available internal diameters is estimated mathematically and confirmed experimentally to achieve any sampling time using any size sampler. The flow rate obtained from the controller is constant over its operating range and is designed to meet a specific sampling duration to obtain long-term integrated samples. The sampling process becomes completely passive, precise, reliable and simple to operate.
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