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General
Guidelines
for Flow Meter Selection
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Flow
Meter |
Recommended
Service |
Turndown |
Typical
Pressure
Loss |
Typical
Accuracy
FS = Full Scale |
Required
Upstream
pipe,
diameters |
Effects from
changing viscosity? |
|
Turbine |
Clean, viscous
liquids |
20 to 1 |
High |
+/- 0.25% of
rate |
5 to 10 |
High |
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Positive
Displacement |
Clean, viscous
liquids |
10 to 1 |
High |
+/- 0.5% of
rate |
None |
High |
|
Electromagnetic
(Mag-Meter) |
Clean, dirty,
viscous, conductive liquids
and slurries |
40 to 1 |
None |
+/- 0.5% of
rate |
5 |
None |
|
Variable Area
(VA, Rota-meter) |
Clean, dirty,
viscous liquids |
10 to 1 |
Medium |
+/- 1 to 10%
FS |
None |
Medium |
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Thermal Mass Flow (TMF) |
Clean dirty
viscous
liquids some
slurries |
10 to 1 |
Low |
+/- 1% FS |
None |
None |
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Coriolis Mass Meter |
Clean, dirty.
viscous
liquids, some
slurries |
10 to 1 |
Low |
+/- 0.5% of
rate |
None |
None |
|
Orifice Plate
|
Clean, dirty,
liquids some
slurries |
4 to 1 |
Some |
+/- 2 to 4% FS |
10 to 20 |
High |
|
Pitot tube |
Clean liquids |
3 to 1 |
Very low |
+/- 3 to 5%
FS |
20 to 30 |
Low |
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Ultrasonic
(Doppler)
|
Dirty, viscous,
liquids and
slurries |
10 to 1 |
None |
+/- 5% FS |
5 to 30 |
None |
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Ultrasonic
(Transit Time)
|
Clean, viscous,
liquids some dirty liquids (depending on brand) |
40 to 1 |
None |
+/- 1 to 3%
FS |
10 |
None |
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Venturi |
Some slurries but clean, dirty and
liquids with high viscosity |
4 to 1 |
A little |
+/- 1% FS |
5 to 18 |
High |
|
Vortex |
Clean, dirty
liquids |
10 to 1 |
Medium |
+/- 1% of rate |
10 to 20 |
Medium |
The recommendations made above are for
general use, under typical conditions only.
For additional information and/or
assistance selecting a flow meter for your specific application,
Call the Flow Experts at Cross
Instrumentation... (800) 332-3418
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