|
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
|
