Meter Application Rules; Sensor Placement In Piping - Omega FMG600 Series User Manual

5. METER APPLICATION RULES

5.1. Sensor placement in piping

No chemical injection or batching unit (such as chlorine compound injector) should be located at the input
side of the sensor. The insufficient homogeneity of the flowing liquid may affect the flow-rate values indicated
by the meter.
The meter performance will be the best if the liquid flow in the piping is well stabilized; therefore it is
necessary to observe specific rules for the sensor placement in piping. In the contact planes between the
sensor and the adjoining piping sections should be no edges as these would cause flow turbulence. Make
sure that straight piping sections are provided before and after the sensor; their required length is
proportional to the inner diameter of the piping concerned.
If more than one flow-disturbing element such as pipe bend or fitting is located near the sensor, the required
length of straight piping section on the sensor side concerned should be multiplied by the quantity
of such elements.
In the cases of bi-directional flow-rate measurement, the same conditions concerning flow stability shall be
met at the input and output sides of the sensor.
Required straight piping sections
.
Pipe narrowing sections with angles not exceeding 8° can be taken for straight sections (see picture above)
Design, Assembly and Service Manual
Induction flow meter FMG600 series
In the case where the pipeline nominal size is bigger
than nominal size of flow meter, it is necessary to use
conical reduction with the maximum slope 15°. In the
case of bi-directional flow, conical reduction must be
installed on both sides, both with minimum straight
piping 5 DN. In the case of horizontal installation,
eccentric reduction must be use to prevent bubbling.
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Pipe narrowing