Endress+Hauser promag 31, Operating Manual

Page: 53 / 60

6.4 Nominal diameter and flow rate
As a rule the pipe diameter governs the nominal diameter of the sensor. When the
volume flow is known, it is possible to estimate from the table below whether the
optimal velocity range of 2...3 m/s can be adhered to.
The flow velocity (v) also has to matched to the physical properties of the medium:
•
v < 2 m/s: with abrasive media (potter’s clay, lime milk, or slurry)
•
v > 2 m/s: with media forming a coating (waste-water sludge, etc.)
If it is necessary to increase the flow velocity, this can be done by reducing the
nominal diameter of the sensor.
The table below summarizes the minimum and maximum full-scale values (incl. works
setting) which can be set by miniature switches in Promag 31.
Diameters DN 800...DN 2000 are also approved.
Measuring points with these diameters are however normally not approved
for cold water fiscal metering (Q
max
>2000 m
3
/h).
Metrological Classes
DN A [m
3
/h] B [m
3
/h]
[mm] Q
n (min)
Q
n (max)
Q
n (min)
Q
n (max)
15 0.8 3 1.6 3
25 2.2 8.8 4.4 8.8
32 3.6 15 7.2 15
40 5.6 22 11.3 22
50 9.0 35 *15 35
65 15 60 20 60
80 *15 90 30 90
100 18 140 46 140
125 28 220 73 220
150 40 220 105 220
200 70 550 190 550
250 110 880 290 880
300 160 1250 420 1250
350 215 1700 570 1700
400 280 2200 750 2200
500 440 3500 1170 3500
600 640 5000 1700 5000
Q
n (min)
with reference to Q
min
(v = 0.05 m/s)
Q
n (max)
with reference to v = 5 m/s
* = Limit range Q
≥
15 m
3
/h
Q
mi
n
:
Q
n
=
1
:
2
5
Q
mi
n : Q
n
=
1 :
50
Q
mi
n :
Q
n
=
1
: 1
2
.5
Q
mi
n
:
Q
n
=
1 :
33
Promag 31 6. Technical Data
Hauser 53