|
Flowmeter element
|
Recommended Service
|
Rangeability
|
Pressure Loss
|
Typical Accuracy, percent
|
Required Upstream pipe, diameters
|
Viscosity effect
|
Relative Cost
|
|
Orifice
|
Clean, dirty liquids; some slurries
|
4 to 1
|
Medium
|
±2 to ±4 of full scale2
|
10 to 30
|
High
|
Low
|
|
Wedge
|
Slurries and Viscous liquids
|
3 to 1
|
Low to medium
|
±0.5 to ±2 of full scale
|
10 to 30
|
Low
|
High
|
|
Venturi tube
|
Clean, dirty and viscous liquids; some slurries
|
4 to 1
|
Low
|
±1 of full scale
|
5 to 20
|
High
|
Medium
|
|
Flow nozzle
|
Clean and dirty liquids
|
4 to 1
|
Medium
|
±1 to ±2 of full scale
|
10 to 30
|
High
|
Medium
|
|
Pitot tube
|
Clean liquids
|
3 to 1
|
Very low
|
±3 to ±5 of full scale
|
20 to 30
|
Low
|
Low
|
|
Elbow meter
|
Clean, dirty liquids; some slurries
|
3 to 1
|
Very low
|
±5 to ±10 of full scale
|
30
|
Low
|
Low
|
|
Target meter
|
Clean, dirty viscous liquids; some slurries
|
10 to 1
|
Medium
|
±1 to ±5 of full scale
|
10 to 30
|
Medium
|
Medium
|
|
Variable area
|
Clean, dirty viscous liquids
|
10 to 1
|
Medium
|
±1 to ±10 of full scale
|
None
|
Medium
|
Low
|
|
Positive Displacement
|
Clean, viscous liquids
|
10 to 1
|
High
|
±0.5 of rate3
|
None
|
High
|
Medium
|
|
Turbine
|
Clean, viscous liquids
|
20 to 1
|
High
|
±0.25 of rate
|
5 to 10
|
High
|
High
|
|
Vortex
|
Clean, dirty liquids
|
10 to 1
|
Medium
|
±1 of rate
|
10 to 20
|
Medium
|
High
|
|
Electromagnetic
|
Clean, dirty viscous conductive liquids and slurries
|
40 to 1
|
None
|
±0.5 of rate
|
5
|
None
|
High
|
|
Ultrasonic (Doppler)
|
Dirty, viscous liquids and slurries
|
10 to 1
|
None
|
±5 of full scale
|
5 to 30
|
None
|
High
|
|
Ultrasonic(Time-of-travel)
|
Clean, viscous liquids
|
20 to 1
|
None
|
±1 to ±5 of full scale
|
5 to 30
|
None
|
High
|
|
Mass(Coriolis)
|
Clean, dirty viscous liquids; some slurries
|
10 to 1
|
Low
|
±0.4 of rate
|
None
|
None
|
High
|
|
Mass (Thermal)
|
Clean, dirty viscous liquids; some slurries
|
10 to 1
|
Low
|
±1 of full scale
|
None
|
None
|
High
|
|
Weir (V-notch)
|
Clean, dirty liquids
|
100 to 1
|
Very low
|
±2 to ±5 of full scale
|
None
|
Very Low
|
Medium
|
|
Flume (Parshall)
|
Clean, dirty liquids
|
50 to 1
|
Very low
|
±2 to ±5 of full scale
|
None
|
Very low
|
Medium
|
|
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