Research on Methods to Reduce the Influence of Medium Evaporation on Liquid Micro-Flow Facility

L. Liu, C. Zhou, T. Meng

Abstract

Liquid micro-flow facility in our country can achieve ultralow flow measurement as low as 100nL/min. In the detection process of liquid micro-flow facility, evaporation is significant for liquid at low flow rate, and if not controlled, the evaporation of the medium will be the main source of uncertainty for liquid micro-flow facility, so it is necessary to correct the evaporation effect during the test. Evaporation occurs mainly during the collection of liquid in the weighing container inside the balance, the effect of evaporation on flow is analysed, and obtains an evaluation method of the effect of reducing evaporation. The influence of balance drift on evaporation was excluded through experiment, and the research on evaporation under uninhibited conditions, evaporation under evaporation trap and oil film coverage were carried out. In addition, the evaporation studies under oil film coverage plus evaporation trap was also implemented. Finally, it is concluded that both the evaporation trap and the oil film covering can effectively inhibit the evaporation of medium, the optimal anti-evaporation method of the liquid micro-flow facility is to cover the paraffin oil film above 0.15 g/cm², which can reduce the evaporation to 0.3 μg/min, and the uncertainty to 0.12 % (k = 2) at the ultralow flow rate of the facility.

Keywords

Metrology; Liquid Micro-Flow; Evaporation; Evaporation Trap; Oil Film

Download

IMEKO-TC9-2019-133.pdf

DOI

10.21014/tc9-2022.133

IMEKO TC

TC9 - Flow Measurement

Back to the proceedings