Nivus NFP, Инструкция по эксплуатации

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Functional Principle
NFP - rev. 04 / 23.05.2018 page 19
Functional Principle
17 Operating Range
The NFP is a permanent measurement system for flow measurement of slightly to heavily
polluted media with various consistencies in constantly full filled pipes.
Important Note
The measurement method used for flow velocity detection is based on the ultrasound re-
flection principle.
Hence, it is indispensable for the system to work that there are particles in the water, which
are able to reflect the ultrasonic signal sent by the sensor (dirt particles, gas bubbles or
similar).
18 Flow Velocity Measurement
The piezo crystal has a slope to the flow direction and operates as a flow velocity sensor.
Here an ultrasonic burst with a defined angle is sent into the medium. All the particles in the
measurement path (air, dirt) reflect a small amount of the ultrasonic signal. The result is a
particular signal depending on shape and size of the particles.
Hence, the multitude of the reflected signals results in a reflection pattern (see Fig. 18-1). The
piezo crystal receives this pattern again, which then is converted into electric signals and will
be saved in a built-in digital signal processor (DSP). This DSP is located within the active
pipe sensor.
1 Pipe wall
2 Pipe sensor
E1…E7 Reflecting particles
1, 2, 3, 4, n Measurement window
Fig. 18-1 Situation at first signal detection