Operation & Installation Manual V12-V6 2010-05-31.doc
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using a number of measuring chords intersecting the flow in different planes, as shown in
Figure 2-5.
Figure 2-5: Path configuration and pipe cross section with multiple acoustic paths.
The total volume flow is calculated by means of an integration algorithm using the results
from the individual paths.
As swirl components are already compensated for in each individual measuring plane, the
integration method using data from multiple paths makes the ALTOSONIC V12 highly
insensitive for any kind of distortion of the flow profile.
The average speed of sound is calculated as the average of the speed of sound values
measured on each of the chords. Normally these values are very close to each other.
2.2 General description.
The ALTOSONIC V12 meters consist of a meter body with an electronic unit installed on top
of it (Figure 2-6). A number of ultrasonic transducers is installed inside the meter body. For
an ALTOSONIC V12 six transducers are installed on one side of the meter body, four
transducers are located on the other side of the meter body and two transducers are installed
on the upper side of the meter.
Each pair of ultrasonic transducers constitute an acoustic path (measuring path) with 2
chords arranged in a V-shape. Five transducer pairs and the corresponding acoustic paths
are located in horizontal planes perpendicular to the pipe axis.
The measured gas velocity is calculated from the data of these five horizontal planes.
Two chords are located in a vertical plane perpendicular to the axis. These are mainly used
for diagnostic purposes.
The signals sent by transducers in planes that are offset from the meter centre line are
reflected via acoustic mirrors to the receiving transducers. These acoustic mirrors are not
required for the two paths going through centre of the meter.
