ABB TRIO-WIRL ST4000 User Manual

Swirlmeter (TRIO-WIRL S) 2 - 10 PN25080
TRIO-WIRL INSTRUCTION MANUAL
2.5.2 Liquid
The maximum required flowrate should not be less
than 0.5 x Qvmax if possible, but can be set as low as
0.15 Qvmax if required.
1. Convert mass flowrate Qm to actual volume flowrate
Qv:
ρ = Operating density [lb/ft
3
]
Q
V
= Actual volume flowrate [ft
3
/h]
Q
m
= Mass flowrate [lb/h]
2. Pressure Drop [psi]
See Figure 2-11 for water (ρ= 8.34 lb/gal)
For other fluid densities the pressure drop can be cal-
culated using the following equation:
∆p’= Pressure drop fluid [psi]
∆p = Pressure drop water [psi] (from Figure 2-11)
ρ = Fluid density [lb/gal] (at operating conditions)
3. Static Pressure
To prevent cavitation when metering liquids a positive
static pressure (back pressure) is required. Its value
can be estimated using the following equation:
p
2
≥ (1.3 x p
Vapor
) + (2.6 x ∆p`)
p
2
= Positive downstream static pressure [psia]
p
Vapor
=Fluid vapor pressure at operating temperature
[psia]
∆p` =Fluid pressure drop [psia]
2.5.2.1 Example for Liquids:
Determine the flowmeter size and pressure drop for
metering 18000 gph liquid with a density of 7.50 lb/gal.
1. Refer to Table 2-3 to see 3”/ DN 80 meter has a
range of 1320 - 26400 gph
2. Using Figure 2-11, find pressure drop at Qv =
18000 gph and ρ = 7.50 lb/gal
∆ρ` = psi = 6.3 psi
TABLE 2-3. SWIRL FLOW RANGES, LIQUID
Meter Size
Flow Range
GPH
Frequency
at Q
V
max
[Hz]
Re min
Inch DN Qvmin Qvmax
1/2 15 30 420 185 2100
1 25 120 1560 135 5200
1-1/4 32 240 2640 107 7600
1-1/2 40 420 4200 110 13500
2 50 660 6600 90 17300
3 80 1320 26400 78 15000
4 100 2100 39600 77 17500
6 150 4740 97800 50 35000
8 200 6600 132000 30 44000
12 300 26400 264000 16 118000
16 400 47400 475500 13 160000
Q
V
Q
m
ρ
----------=
∆p'
ρ
8.34
----------
∆p×=
7.5
8.34
----------
7⋅

ABB TRIO-WIRL ST4000 Specifications

General

Brand	ABB
Model	TRIO-WIRL ST4000
Category	Measuring Instruments
Language	English