ABB TRIO-WIRL SR4000, Instruction Manual

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PN25080 Vortex Meter (TRIO-WIRL V) 3 - 11
TRIO-WIRL INSTRUCTION MANUAL
3.5 Vortex Meter Size Selection
The maximum required actual volume flowrate Q
V
at
operating conditions is the basis for the flowmeter size
selections. In order to utilize the maximum flow range
this value should not be less than one half of the maxi-
mum flowrate for the meter size (Q
Vmax
). The linear
flow range (see Accuracy Specifications) corresponds
to the Reynolds Number (R
e
) range from 20,000 (or
40,000 for 6” / DN 150) to 7,000,000.
If the flowrate to be metered is expressed as a stan-
dard flowrate (70
o
F, 14.7 psia) or as a mass flowrate, it
will be necessary to first convert these values to their
equivalent actual volume flowrate at operating condi-
tions before selecting the most suitable flowmeter size
from the Flow Range Tables (Tables
3-1 & 3-4 to 3-6 ).
1. Convert standard density (
ρ
s
) to operating den-
sity (
ρ
).
2. Convert to actual volume flowrate (Q
V
).
a) Starting from standard flowrate (Q
s
) :
b) Starting from mass flowrate (Q
m
) :
3. Dynamic viscosity,
µ
(cps) to kinematic
viscosity,
ν
(cst)
4. Reynolds Number (R
e
)
Where:
ρ = Density at operating conditions (lb/ft
3
)
ρ
S
= Density at standard conditions (lb/ft
3
)
p = Pressure at operating conditions (psig)
T = Temperature at operating conditions (ºF)
Q
V
= Actual volume flowrate (acfh)
Q
S
= Standard flowrate (scfh)
Q
m
= Mass flowrate (lb/hr)
3.5.1 Gas
ρ ρ
s
14.7 p
+
14.7
--------------------
×
530
460 T
+
-------------------
×
=
Qv Q
s
ρ
s
ρ
-----
 
 
Q
=
s
14.7
14.7 p
+
-------------------- 460
T
+
530
-------------------
×
 
 
=
Qv
Q
m
ρ
--------
=
ν
µ
ρ
---
=
Re
3160 gpm
×
ν
------------------------------
=
TABLE 3-1. VORTEX FLOW RANGES, AIR
Meter Size
Flow Range
[acfh]
Frequency [Hz]
at Qvmax
Inch DN
Qvmin Qvmax
1/2 15 180 780 1840
1 25 425 2900 1825
1-1/2 40 740 12000 2000
2 50 1500 15900 1250
3 80 2750 33500 760
4 100 4240 63500 650
6 150 9200 143000 425
8 200 14800 240000 310
10 250 29000 424000 235
12 300 45900 600000 190
Air at 70 °F, 14.7 psi,
ρ
= 0.075 lb/ft
3
TABLE 3-2. STANDARD DENSITIES FOR
SELECTED GASES
Gas Standard Density [lb/ft
3
]
Acetylene 0.0732
Air 0.0749
Ammonia
0.0481
Argon 0.1111
Butane 0.1686
Carbon Dioxide 0.1230
Carbon Monoxide 0.0780
Ethane 0.0843
Ethylene 0.0787
Hydrogen 0.0056
Methane 0.0448
Natural Gas 0.045
Neon 0.0556
Nitrogen 0.0780
Oxygen 0.0893
Propane 0.1261
Propylene 0.1196