Siemens SITRANS L Operating Instructions Manual page 23

Installing/mounting
4.4 Measurement setup - Flow
Predefined curves
A flow measurement with these standard curves is very easy to set up, as no
dimensional information of the flume is required.
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Dimensions (ISO standard)
When selecting these curves, the dimensions of the flume must be known and
entered via the assistant. As a result, the accuracy of the flow measurement is higher
than with the specified curves.
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Flow formula
If the flow formula of your flume is known, you should select this option, as the
accuracy of the flow measurement is highest here.
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Manufacturer definition
If you use a Parshall flume from the manufacturer ISCO, this option must be selected.
This gives you a high accuracy of flow measurement with easy configuration.
Alternatively, you can also take over Q/h table values provided by the manufacturer
here.
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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.
16
Palmer-Bowlus flume (Q = k x h
Venturi, trapezoidal weir, rectangular flume (Q = k x h
V-Notch, triangular overfall (Q = k x h
Rectangular flume (ISO 4359)
Trapezoidal flume (ISO 4359)
U-shaped flume (ISO 4359)
Triangular overfall thin-walled (ISO 1438)
Rectangular flume thin-walled (ISO 1438)
Rectangular weir broad crown (ISO 3846)
Flow formula: Q = k x h
ISCO-Parshall-Flume
Q/h table (assignment of height with corresponding flow in a table)
1.86
)
2.5
)
exp
1.5
)
SITRANS LR100
Operating Instructions, 10/2021, 62705-76-01