26
4 Mounting
VEGAPULS 64 • 4 … 20 mA/HART - two-wire
51141-EN-160815
Fig. 22: Agitators
Through the action of filling, stirring and other processes in the vessel,
compact foam can form on the product surface, damping the emitted
signals considerably.
If foams lead to measurement errors, you should use the biggest pos-
sible radar antennas or sensors with guided microwave.
4.5 Measurement setup - Flow
The short examples give you introductory information on flow
measurement. Detailed planning information is available from flume
manufacturers and in special literature.
h
ma
x
≥ 2 x h
ma
x
90°
4
3 ... 4 h
max
90°
2
3
1
Fig. 23: Flow measurement with rectangular overfall: d
min.
= min. distance of
the sensor (see chapter "Technical data"); h
max.
= max. filling of the rectangular
spillway
1 Overflow orifice (side view)
2 Headwater
3 Tailwater
4 Overfall orifice (view from tailwater)
In general, the following points must be observed:
•
Install the sensor on the headwater side
•
Installation in the centre of the flume and vertical to the liquid
surface
Foam generation
Flow measurement with
rectangular overfall
