3 General principles
3.2 Measurement arrangements
FLUXUS F808
2020-06-25, UMFLUXUS_F808V2-2EN
14
3.1.4
Measurement of the flow velocity in the HybridTrek mode
The HybridTrek mode combines the TransitTime and the NoiseTrek mode. During a measurement in the HybridTrek
mode, the transmitter automatically toggles between the TransitTime and the NoiseTrek mode depending on the gaseous
or solid content.
The measurement arrangement is identical to the one in the TransitTime mode.
3.1.5
Measurement of the flow velocity in the NoiseTrek parallel beam mode
Pipes with a small pipe diameter or fluids which strongly attenuate the ultrasonic signal can cause a reduction of the transit
time in the fluid with the result that the signal quality is no longer sufficient. In this case the NoiseTrek parallel beam mode
has to be used.
The NoiseTrek parallel beam mode works the same way the NoiseTrek mode does, the only difference is that the sending
and receiving process do not occur in the same transducer. This leads to a better signal quality. The transducers are
mounted in parallel on the pipe at a small distance, see Fig. 3.5.
A measurement in TransitTime mode is not possible when working with this measurement arrangement.
3.2
Measurement arrangements
3.2.1
Terms
Sound path
The distance covered by the ultrasonic signal after crossing the pipe once. The number of the sound paths is:
• odd if the measurement is carried out in diagonal arrangement
• even if the measurement is carried out in reflection arrangement
Beam
The path covered by the ultrasonic signal between the transducers, i.e., the transducer emitting the ultrasonic signal and
the transducer receiving it. One beam consists of 1 or several sound paths.
Fig. 3.5:
Measurement arrangement in the NoiseTrek parallel beam mode
Diagonal arrangement
Reflection arrangement
The transducers are mounted on opposite sides of the pipe.
The transducers are mounted on the same side of the pipe.
Fig. 3.6:
Diagonal arrangement with 1
beam and 3 sound paths
Fig. 3.7:
Reflection arrangement with 1
beam and 4 sound paths