Name of the standard: National Standard of Very Small Liquid Flows
Code designation: ECM 142-1/19-062
Year of publication: 2019
Department: department 6015 CMI OI Brno
Guarantor: Ing. Miroslava Benková, Ph.D.
Number of CMC lines provided: -
The benchmark was established to ensure the transfer of the unit of very small liquid flow rates (l/s) and very small liquid flow rates (L) to working benchmarks of lower orders and to working meters in the Czech Republic.
In terms of accuracy, stability of measurement, the possibility of connection of individual meter principles and the influence of measurement uncertainties, the primary mass method with scales was used in the field of micro-flow measurement. For more efficient measurements, the use of precision flow meters as secondary reference meters was considered. In order to make use of a relatively wide range of measuring principles, the device operates with both a soft and a hard start.
The National Standard of Very Small Liquid Flows consists of the following components:
- a storage tank with liquid exchange capability (distilled water),
- filter, for flow rates up to 500 ml/h,
- flow source - two pumps with a range of (10 to 600)g/h and (500 to 6000)g/h,
- control branches with control valve and flow adjustment,
- reference coriolis flow meters with a range of (10 to 600)g/h and (500 to 6000)g/h and -
- temperature up to 50°C,
- a measuring section for mounting the meter(s) in the range (10 to 600)g/h and (500 to
- 6000)g/h with PT100 reference thermometers,
- scales with an accuracy of 0,1mg/0,01mg,
- control unit and evaluation device.
Basic metrological characteristics:
Measuring range: (10 to 6 000) g/h
(10 to 6 000) ml/h
Working pressure: (140 - 340) Pa
Test liquid: Distilled water
Water temperature: (25 ± 5 ) °C
Expanded uncertainty (CMC) - 0,50 % mass flow rate for a flow rate of (10 to 30) g/h
0,15 % for a flow rate of (30 to 2000) g/h
0,20 % for flow rate (2000 to 6000) g/h
Expanded uncertainty (CMC) - volumetric flow rate 0,60 % for a flow rate of (10 to 30) ml/h
0,20 % for flow rate (30 to 2000) ml/h
0,25 % for flow rate (2000 to 6000) ml/h