Grounding; Inlet And Outlet Sections - ABB ProcessMaster FEM630 Operating Instructions Manual

FE M63 0 | E L EC TR OM AG N E T I C FLOWM E T E R | O I/F E M6 3 0-EN RE V. A
5 . . .Installation
. . .Installation conditions

Grounding

The flowmeter sensor must be connected to ground
potential. For technical reasons, this potential must be
identical to the potential of the measuring medium.
In piping made of plastic or with insulating liner, grounding of
the measuring medium is done by installing grounding plates.
If stray potential is present in the piping, adding a grounding
plate on both ends of the flowmeter sensor is recommended.

Inlet and outlet sections

1
Double manifold
2
Turn-off device
Figure 12 Inlet and outlet section, turn-off devices
The measuring principle is independent of the flow profile as
long as standing eddies do not extend into the measured
value formation, such as may for example occur after double
manifolds, in the event of tangential inflow, or where half-
open gate valves are located upstream of the sensor. In such
cases, measures must be put in place to normalize the flow
profile.
Do not install fittings, manifolds, valves, etc., right before
A
the flowmeter sensor.
Inlet / outlet sections: length of the straight piping
B
upstream and downstream on the sensor.
Experience has shown that, in most installations, straight
inlet sections 3 × DN long and straight outlet sections 2 ×
DN long are sufficient (DN = nominal diameter of the
flowmeter sensor).
For test stands, the reference conditions of 10 × DN
straight inlet and 5 × DN straight outlet must be provided,
in accordance with EN 29104 / ISO 9104.
Valves or other turn-off devices should be installed in the
outlet section.
Valve flaps must be installed so that the valve damper
plate does not extend into the flowmeter sensor.
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