6
3 Functions and features
Pressure Equipment Directive (PED): The units comply with section 3, article (3)
of the Directive 97/23/EC and must be designed and manufactured for non-super-
heated liquids of group 1 fluids in accordance with the sound engineering practice�
The unit monitors liquid media�
The unit detects the 3 process categories volumetric flow quantity, consumed
quantity and medium temperature�
Application area
Conductive liquids with the following properties:
• Conductivity:≥20µS/cm
• Viscosity: < 70 mm
2
/s at 40°C
4 Function
4.1 Measuring principle for volumetric flow monitoring
The magnetic-inductive measuring principle means that a magnetic field is gener-
ated in the measuring pipe via current-carrying coils� When a conductive medium
flows through the measuring pipe, the ions therein are diverted perpendicularly to
the magnetic field� Positive and negative charge carriers flow in opposite direc-
tions� The voltage induced is measured by two electrodes that are in contact with
the medium� This signal voltage is directly proportional to the average flow veloc-
ity� The volumetric flow quantity is derived from the internal pipe diameter�
3
1
2
4
5
1: Field coil
2: Measuring pipe
3: Electrode
4: Charge carrier in the medium
5: Magneticeld
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