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AquaProbe FEA100 / FEA200
Electromagnetic flowmeter
When the probe insertion position is determined, the effect of putting the probe into the pipe (see
Section 3.3.2, page 11) must be calculated.
The blockage or insertion effect is termed the Insertion Factor (Fi). This is a mathematical relationship and
can be calculated from the formula:
A.2 Testing the Flow Profile for Symmetry
If there is any doubt as to the symmetry of the flow profile (see Section 3.3, Page 10), a Partial Velocity
Traverse should be carried out. This procedure involves comparing the value of velocity at two points at
equal distances from the centre line.
It is normal to compare the flow velocities at insertion depths of
points are always on the 'knee' of the profile.
A.2.1 Partial Velocity Traverse
Determine the internal diameter D of the pipe, in millimeters, by the most accurate method available. If the
flow sensor insertion length is greater than the internal diameter of the pipe, proceed with the Single Entry
Point Method detailed in Section A.2.2. If the flow sensor's insertion length is less than the internal diameter
of the pipe, proceed with the Dual Entry Point Method detailed in Section A.2.3, page 30.
A.2.2 Single Entry Point Method
1. Insert the flow sensor to a depth of
Note. Due to software configuration, all calculations are in metric units. Therefore if using an
imperial pipe, the diameter MUST be converted into millimeters (1 in. = 25.4 mm, for example, a
36 in. pipe = 914 mm).
2. Calculate the insertion factor
12.09
-------------- -
=
+
+
1
i
D
3. Refer to the relevant user guide* and enter an Insertion Factor of value equal to F
4. Record the flow velocity reading.
5. Insert the flow sensor to a depth of
6. Calculate the insertion factor.
12.09
-------------- -
=
+
+
1
i
D
7. Refer to the relevant user guide* and enter an Insertion Factor of value equal to F
8. Record the flow velocity reading.
9. Calculate the ratio of the two values recorded.
– if the calculated ratio is between 0.95 and 1.05, the flow profile is acceptable and the procedure
detailed in Section 5.2, Page 22 can be used,
or
– if the calculated ratio is
*WaterMaster FET100 (OI/FET100–EN) or AquaMaster3 FET200 (OI/FET200–EN)
OI/FEA100/200–EN Rev. D
Fi
1
/
the pipe diameter – see Fig. 3.11, page 18.
8
1.3042
----------------- -
D
7
/
the pipe diameter.
8
1.3042
----------------- -
D
between 0.95 and 1.05, re-site the flow sensor for optimum accuracy.
not
1
=
-------------------------------- -
D
–
1
38
1
/
8
7
and
/
of the pipe diameter as these
8
.
i
.
i
29
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