Some Guidelines in Flowmeter Selection for Liquids
Flowmeter element	Recommended Service	Rangeability	Pressure Loss?	Typical Accuracy, percent	Required Upstream pipe, diameters	Effects from changing viscosity?
Coriolis mass Meter	Clean dirty viscous liquids some slurries	10 to 1	Low	±0.5 of rate	None	None
Elbow meter	Clean dirty liquids some slurries	2.5 to 1	Very low	±5 to ±10 of full scale	30	Low
Electromagnetic	Clean, dirty viscous con- ductive liquids and slurries	40 to 1	None	±0.5 of rate	5	None
Flow nozzle	Clean and dirty liquids	4 to 1	Medium	±1 to ±2 of full scale	10 to 30	High
Orifice	Clean, dirty liquids; some slurries	4 to 1	Some	±2 to ±4 of full scale	10 to 20	High
Pitot tube	Clean liquids	3 to 1	Very low	±3 to ±5 of full scale	20 to 30	Low
Positive Displacement	Clean viscous liquids	10 to 1	High	±0.5 of rate	None	High
Target meter	Clean dirty viscous liquids some slurries	8 to 1	Medium	±1 to ±5 of full scale	10 to 28	Medium
Thermal Mass	Clean dirty viscous liquids some slurries	10 to 1	Low	±1 of full scale	None	None
Turbine	Clean, viscous liquids	20 to 1	High	±0.25 of rate	5 to 10	High
Ultrasonic (Doppler)	Dirty, viscous liquids and slurries	10 to 1	None	±5 of full scale	5 to 30	None
Ultrasonic (Transit Time)	Clean, viscous liquids some dirty liquids(depending on brand)	40 to 1	None	±1 to 3 of full scale	10	None
Variable area	Clean dirty viscous liquids	10 to 1	Medium	±1 to ±10 of full scale	None	Medium
Venturi	Some slurrys but clean dirty and liquids with high viscosity	4 to 1	A little	±1 of full scale	5 to 18	High
Vortex	CLean, dirty liquids	10 to 1	Medium	±1 of rate	10 to 20	Medium
Wedge	Slurries and liquids with high viscosity	4 to 1	A little	±0.5 to ±2 of full scale	10 to 30	Low
Weir V-notch	Clean, dirty liquids	100 to 1	Very low	±2 to ±5 of full scale	None	Very Low

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Dwyer J has submitted this flow article. Flowmeterdirectory in no way
claims the accuracy of the above chart nor will be held liable for the contents thereof.