The following information is from Krohne Webinars and Zero Instrument Prepare
Electro Magnetic Flowmeters measure the volume flow of conductive liquids
Typical media
●Drinking water & wastewater
●Industrial process water & cooling water
●Liquid chemicals
●Slurries, pulps and pastes
Constraints;
● Minimum electrical conductivity
● Only for liquids
Applicable in virtually any industry
Measuring principle
Construction of flow sensor
●Measuring tube
●Liner
●Electrode pair
●Field coil pair
●Coil housing
●Converter
Robust, Reliable & Safe
Full bore, free of obstructions, no moving parts
-Maintenance free
– Long-term stability
– No abrasion
– Inlet & outlet lengths
Outstanding measurement performance
Even under harsh medium & installation conditions
– Viscosity/ Reynolds independent
– Solids/ gas bubbles
– Vibrations
Measurement performance
Grounding/ Functional Ground (FE)
An EMF requires a reliable and fixed reference, because
the measured signal is a very small voltage (mV).
When installed between metallic pipes the medium will be
connected to ground to establish the reference.
Non-metallic or internally coated pipes do not have a
connection to the ground.
Therefore a reference must be established:
●Grounding rings
●Grounding electrode
●Reference electrode
●Virtual reference
Virtual reference
●Eliminates the need for grounding of process fluid;
●Flowmeter wiring exactly the same, but the earth connection
to liquid is redundant.
●Advantages:
– Easy installation
– Safety: Less leakage paths
– Costs: no precious metal grounding electrodes 1 rings
Measurement performance
Optimization of measurement performance
●Converter performance
-Strong signal & signal handling
– Filtering techniques
Sensor performance
– Electrode selection to reduce the effect of impact of particles
Results:
●Stable & responsive flow measurement
Even at solids contents up to 70%
●Increased lifetime
Optimization of measurement performance
●Converter performance
-Strong signal & signal handling
一Filtering techniques
●Sensor performance
– Electrode selection to reduce effect of impact of particles
Flow sensor
●electrode fouling or scaling
●electrode corrosion
●electrode leakage
●liner deformation
●coil performance
Flow converter
●linearity check
●I/O check
● Functioning of converter components
Process I installation
●gas bubbles & solids
●liquid conductivity
●temperature
●flow profile
●partially filled pipe
Display:
●NE107 Icons I colors indicate a status message
●all information on diagnostics via menu
Outputs :
●status outputs:
all warnings
●analog (4 – 20 mA): conductivity, temperature
Bus communication:
●HART
●Foundation Fieldbus
●Profibus PA
●Ethernet
●Modbus
Verification
(Dry) Field verification
●Tests under installation or application conditions on site
●No need to remove the flowmeter out of the line
(Wet) Factory Calibration
●Tests under reference conditions at the factory
●Flowmeter need to be removed and transported
Verification | Proof testing
IFC 400: Capable for proof testing
●Required to detect dangerous undetected (by
diagnostics) faults: 2DU
●IFC 400 is capable for automated partial proof
testing
●This allows to extend the intervals for full proof tests
