ABB COPA-XT DT43F Instruction Bulletin page 10

Electromagnetic Flowmeter COPA-XT
In a free flow outlet (drop line) the flowmeter primary should be
not be installed in the highest point or in the discharge of the
pipeline (metering spool could drain, air bubbles, Fig. 5)
Fig. 5
The measurement principle is independent of flow profile as
long as standing eddies do not extend into the measurement re-
gion (e.g. after double elbows, tangential inflows or half open
valves upstream of the flowmeter primary). In such situations
measures to condition the flow profile should be employed. Ex-
perience indicates that in most cases a straight upstream sec-
tion with a length of 3 x DN and a downstream section of 2 x DN
are sufficient (DN = flowmeter primary size) Fig. 6.
In calibration stands the reference conditions of EN 29104 re-
quire straight lengths of 10 x DN upstream and 5 x DN down-
stream.
Wafer valves are to be installed in such a manner that the wafer
when open does not extend into the flowmeter. Valves or other
shut off devices should be installed downstream.
Fig. 6
4
For heavily contaminated fluids a bypass line as shown in
Fig. 7 is recommended so that when mechanical cleaning is
required operation can continue uninterrupted.
.
Fig. 7
For flowmeter primaries which are to be installed in the vicinity
of pumps or other vibration generating equipment, the
utilization of mechanical dampers is advantageous (Fig. 8).
Fig. 8