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5
SETTING UP
5.1 Introduction
The
basic
equation
for
AquaProbe is:
Q = A F
F
V
i
P
Where:
Q
=
flow rate,
F
=
insertion factor
i
F
=
profile factor
p
V
=
velocity
A
=
area
The pipe diameter, profile factor and insertion factor must be
determined as detailed in Sections 5.2 to 5.3, as applicable.
Note. Due to software configuration, all calculations
are in metric units. Therefore if using an imperial pipe, the
diameter
be converted into millimetres (1in =
MUST
25.4mm) i.e. a 36in pipe = 914mm
5.2 Centre Line Method
a) Determine the internal diameter D of the pipe, in
millimetres, by the most accurate method available.
b) Determine the profile factor F
c) Calculate the insertion factor F
Example – for a pipe of internal diameter 593mm (23.35in):
F
= 0.861 (derived from Fig. 5.1)
p
1
F
=
i
1 – (38/593π)
F
= 1.021
i
5.3 Mean Axial Velocity Method (
a) Determine the internal diameter D of the pipe, in
millimetres, by the most accurate method available.
b) A profile factor F
of 1 must be used.
p
c) Calculate the insertion factor F
Example – for a pipe of internal diameter 593mm (23.35in):
F
= 1
p
12.09
1.3042
F
=
1 +
+
i
√593
593
F
= 1.074
i
8
0.875
0.870
0.865
0.860
0.855
0.850
200
Fig. 5.1 Profile Factor vs Velocity for Pipe Sizes 200 to 2000mm (8 to 80in)
14
volume
measurement
using
from Fig. 5.1.
p
1
=
.
1 – (38/πD)
i
1
⁄
Diameter)
8
12.09
1.3042
1 +
+
=
√D
D
i
16
24
32
400
600
800
5.4 Partial Velocity Traverse
Refer to the Appendix A1 for procedure.
5.5 AquaProbe Transmitter Set-up
The AquaProbe Transmitter can be set up to display point
velocity, mean velocity or flow rate, as required. For full
programming details refer to the AquaProbe Transmitter
Configuration Manual.
For velocity measurement set:
VU to 1.000
TU to 1.000
BL to F
x F
i
p
For flow rate ( in any units):
a) Calculate the volume units VU using
π
VU =
x
4
Where
D is the internal pipe diameter in mm
L is the number of volume units in a cubic metre
b) Enter TU for the time display units required, i.e. 1 (per
second) 60 (per minute) etc.
Example – for a pipe diameter of 593mm (23.35in) and flow
rate display in L/m (litres per minute) using centre line method:
π
x
VU =
4
VU = 276.2
and
TU = 60
BL = F
x F
i
p
BL = 1.021 x 0.861
BL = 0.879
Pipe Bore in inches
40
48
56
1000
1200
1400
Pipe Bore in mm
D
2
x L
1000
2
593
x 1000
1000
64
72
80
1600
1800
2000
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