Operation & Installation Manual V12-V6 2010-05-31.doc
31/05/2010
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CAUTION!
The ALTOSONIC V12 should be protected from corrosive chemicals or gases and dust or
particles accumulation.
3.4 Installation requirements
3.4.1. Pipe diameters and lengths
INFORMATION!
The location for installing an ALTOSONIC V12 shall be selected carefully. The location shall
be horizontal (preferred) with sufficient upstream and downstream straight pipe length in
accordance with international and/or company regulations.
The inner diameter of upstream and downstream piping shall match the specified connection
diameter of the ultrasonic flow meter, preferably within 1% but at maximum within 3% (see
e.g. ISO17089 or AGA-9 for details).
The inlet pipe spool of a custody transfer flow meter shall have a straight length of at least
10DN. Also 5DN upstream straight length is allowed pending on the required accuracy class.
The outlet pipe spool shall have a minimum straight length of 3DN.
It is recommended to install the applicable inlet pipe spool in front of the ultrasonic flow meter
during the flow (wet) calibration (see e.g. ISO17089 or AGA-9 for detailed requirements).
3.4.2. Flow conditioners.
Although the ALTOSONIC V12 is a highly accurate device an additional flow conditioner can
be installed upstream of the flow meter in order to minimize measuring uncertainty, in
particular when a strongly distorted flow velocity profile has to be expected, or when the
available space for a metering run is critical. If a flow conditioner is used the total inlet length
may be reduced to only 5DN: having 2DN upstream of the flow conditioner and 3DN in
between the flow conditioner and the meter.
As a flow conditioner the preferred model is the “perforated plate”. Using “pipe bundle” type
of flow conditioner is not recommended.
When a flow conditioner is included in the metering run, it is recommended to use the same
flow conditioner and inlet pipe configuration during a flow (wet) calibration (see e.g.
ISO17089 or AGA-9 for detailed requirements).
3.4.3. Control valves
NOTE!
Under circumstances ultrasonic gas flow meters can suffer from interference from noise
generated by pressure control valves (PCV). In case the frequency spectrum of the PCV-
noise extends in the range of the operating frequency of the ultrasonic transducers and the
strength of the noise results in a signal to noise ratio smaller than the critical value, the
ultrasonic flow meter will not be able to operate. Consult KROHNE for advice in case a PVC
with high pressure cut will be operated in the vicinity of the ultrasonic flow meter.
