Function And System Design - Endress+Hauser prosonic flow 92 Technical Information

Measuring principle
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Function and system design

Prosonic Flow operates on the principle of transit time difference.
An acoustic (ultrasonic) signal is transmitted in both directions from one measuring sensor to the
other. As the signal propagation velocity of the waves is less when the waves travel against the
direction of flow than along the direction of flow, a transit time difference occurs. This difference
is directly proportional to the flow velocity.
Prosonic Flow calculates the flow from the pipe cross-sectional area and the measured transit
time difference.
v ~ ∆ t
Q = v · A
v = flow velocity
∆ t = transit time difference
v = volume flow
A = pipe cross-sectional area
In addition to the volume flow, the system measures the sound velocity in the liquid. The sound
velocity can be used to distinguish different liquids or as a measure of product quality. You can
carry out application-specific calibrations of Prosonic Flow in the field using the Site Setup.
Signal propagation time
For accurate measurement, the ultrasonic signal needs a certain minimum signal propagation
time [t].
The measuring accuracy increases with the length of the signal propagation time (t) in a liquid.
t
Prosonic Flow 92
t/2 t/2
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