Reproducibility of Liquid Micro-Flow Measurements

J. D. Wright, J. W. Schmidt
Abstract:
New applications in biology, medicine, and manufacturing require reliable measurements of liquid flows smaller than 100 μL/min. NIST addressed this requirement by improving the reliability and ease of use of NIST’s Dynamic Gravimetric Micro-Flow Standard. The meter under test is now connected to the weighing beaker by a liquid bridge that reduces variations in parasitic surface tension forces as the level of liquid in the collection beaker rises. We describe other improvements to NIST’s standard (e.g. pipette positioning and evaporation reduction) and provide an uncertainty analysis for the present system. The gravimetric standard measures liquid flow between 0.1 μL/min and 100 μL/min with uncertainty ranging from 4.5 % to 0.04 %. Repeated calibrations of five commercially available micro-flow meters (one for nearly 2 years) show that their calibrations are reproducible within 1.5 % for many months.
Download:
IMEKO-TC9-2019-097.pdf
DOI:
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Event details
IMEKO TC:
TC9
Event name:
FLOMEKO 2019
Title:

18th International Flow Measurement Conference 2019

Place:
Lisbon, PORTUGAL
Time:
26 June 2019 - 28 June 2019