Siemens MAG 1100 Handbook page 22

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SITRANS F M MAGFLO
Inlet and outlet condi-
tions
Potential equalization
Vacuum
Installation in large pipes
22
3. Project guidance
DKFD.PS.027.W3.02
To achieve accurate flow measurement it is es-
sential to have straight lengths of inlet and outlet
pipes and a certain distance between pumps and
valves.
It is also important to centre the flowmeter in
relation to pipe flanges and gaskets.
The electrical potential of the liquid must always
be equal to the electrical potential of the sensor.
This can be achieved in different ways depending
on the application:
A. Wire jumper between sensor and adjacent
flanges. (MAG 1100 and MAG 3100).
B. Direct metallic contact between sensor and
fittings. (MAG 1100 FOOD).
C. Built-in earthing electrodes. (MAG 3100 and
MAG 3100 W).
D. Optional earthing/protection flanges/rings.
(MAG 1100 and MAG 3100).
E. Optional graphite gaskets on MAG 1100.
(Standard for MAG 1100 High temperature).
Avoid a vacuum in the measuring pipe, since
this can damage certain liners.
See "Technical data", chapter 2.
The flowmeter can be installed between two
reducers (e.g. DIN 28545). Assuming that at 8°
the following pressure drop curve applies. The
curves are applicable to water.
Example:
A flow velocity of 3 m/s (V) in a sensor with a
diameter reduction from DN 100 to DN 80
(d /d = 0.8) gives a pressure drop of 2.9 mbar.
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