Flowmeter Accuracy
An introduction to accuracy in flow measurement devices
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Accuracy indicates how close the measured value is to the accepted or true value.
The accuracy of flowmeters can be stated as:
- percent of full span
- percent of rate
Accuracy as Percent of Full Spann
Accuracy in percent of full span can be expressed as:
a% = a 100% / s (1)
where
a% = relative accuracy (%)
a = +/- absolute accuracy
s = full scale of the flowmeter
Example - Accuracy of Flowmeter in Percent of Full Span
If the absolute accuracy is +/- 10 kg/h - the relative accuracy at full scale 1000 kg/h can be calculated as:
a% = (+/- 10 kg/h) 100% / (1000 kg/h)
= +/- 1%
The relative accuracy at full scale 100 kg/h can be calculated as:
a% = (+/- 10 kg/h) 100% / (100 kg/h)
= +/- 10%
Accuracy as percent of Rate
Accuracy in percent of rate can be expressed as:
a% = a 100% / q (2)
where
a% = relative accuracy (%)
a = +/- absolute accuracy
q = flow rate
Example - Accuracy of Flowmeter in Percent of Rate
If the relative accuracy is +/- 1% of rate - the absolute accuracy at rate 1000 kg/h can be calculated as:
a = (+/- 1%) (1000 kg/h)
= +/- 10 kg/h
The absolute accuracy at rate 100 kg/h can be calculated as:
a = (+/- 1%) (100 kg/h)
= +/- 1 kg/h
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Related Topics
- Fluid Flowmeters - Flow metering basics - Orifice, Venturi, Flow Nozzles, Pitot Tubes, Target, Variable Area, Positive Displacement, Turbine, Vortex, Electromagnetic, Ultrasonic Doppler, Ultrasonic Time-of-travel, Mass Coriolis, Mass Thermal, Weir V-notch, Flume Parshall and Sluice Gate flow meters and more
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Related Documents
- Flowmeters and Turndown Ratio - An introduction to turndown ratio for flow measurement devices as orifices, venturi meter etc.
- Types of Fluid Flow Meters - An introduction to different types of fluid flowmeters - Orifices, Venturies, Nozzles, Rotameters, Pitot Tubes, Calorimetrics, Turbine, Vortex, Electromagnetic, Doppler, Ultrasonic, Thermal, Coriolis
