SCP System • System description
22 CP_SEM_60-00-00.002
3.2.3 Functional diagram of flow probe
Fig. 9: Functional diagram of flow probe (1)
The flow rate is measured by two ultrasound transducers D 1 in the flow probe. These emit an
ultrasound signal twice in alternation, which passes through the tube D 3 (i.e. the liquid contained) via
a reflector D 2. Depending on the mean speed of the liquid, the ultrasound signal undergoes a change
in the transit time (and thus produces a phase shift from the original signal).
This dual transit is produced by alternating control of the transducers, once with and once against the
direction of flow, generating different transit times for the reflected ultrasound signals. The absolute
flow rate can be determined from these two values, but only the signals (which pass through the tube)
with an actual change in the transit time are included in the evaluation. The flow rate can thus always
be calculated correctly, irrespective of the tube diameter.
Mod. Item Description
D1Ultrasound transducers (2 x transmitter/
receiver)
D2Reflector
D3Inserted and filled tube
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