HydrINS 2 / HydrINS 2 Mini flow meter
Installation Manual
Page 9 / 79
2.1
Measurement Principle
The velocity measurement principle is based on the application of Faraday's Law, which states that a
voltage is generated by the movement of a conductor through a magnetic field.
In the case of HydrINS 2/HydrINS 2 Mini, the magnetic field is generated by a coil at the end of the
probe, and the water passing through the pipe, whose conductivity must be at least
20 µS/cm
,
represents the conductor.
The electromotive force generated by the passage of the water through the magnetic field,
comparable to a voltage, is measured by the two electrodes, which are visible on both sides of the
stem. Because this electromotive force is proportional to the velocity, the HydrINS 2/ HydrINS 2 Mini
probe carries out a velocity measurement derived from the electromotive force of the water. The
flow rate is then deduced from this velocity measurement.
The electromagnetic sensor is located at the tip of the insertion rod. It has an exciter coil and two
electrodes, seen on the side of the sensor.
Figure 1: Location of the sensor on the HydrINS2/HydrINS 2 Mini flow meter
Probe head and guide bar
Insertion stem
Electrodes
Sensor