Measurement Setup - Flow - Siemens SITRANS L Series Operating Instructions Manual

Foam generation
Through the action of filling, stirring and other processes in the vessel, compact
foam can form on the medium surface, damping the emitted signals considerably.
If foams lead to measurement errors, you should use transmitters with guided radar.
4.4

Measurement setup - Flow

In general, the following must be observed while mounting the device:
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•
•
•
Detailed project planning data can be found at the channel manufacturers and in the
technical literature.
The following examples serve as an overview for flow measurement.
Rectangular overfall
1
2
3
4
Figure 4.9
SITRANS LR120
Operating Instructions, 08/2020, A5E49829026
Mounting the transmitter on the upstream or inlet side
Installation in the centre of the flume and vertical to the liquid surface
Distance to the overfall orifice or Venturi flume
Min. distance to the max. height of damming for optimum accuracy: 250 mm
1
(9.843 in)
Overfall orifice (side view)
Upstream water
Tailwater
Overfall orifice (view from tailwater)
Flow measurement with rectangular flume: h
flume
1
At smaller distances the measuring accuracy is reduced, see "Technical data".
Installing/mounting
4.4 Measurement setup - Flow
= max. filling of the rectangular
max.
17