INLET
OUTLET
With flow straightener the inlet pipe length may be
halved e.g. for a control valve the inlet length is 25D
instead of 50D. The minimum inlet pipe length
including flow straightner must always be 12 D.
4. Pipe
vibration
Pipe Vibration caused, for example, by the action of
pumps, valves, etc., will falsify measurements
particularly at low flow velocities. Support the
pipeline on both sides of the flowmeter, in the
direction perpendicular to both the pipeline & bluff
body axis.
·
Pipe vibration limit is 0.2g _peak to peak upto
8-500 Hz crossover frequency..(which equals
0.75 mm)
5.
Pipeline along a wall
Where possible, the distance between the pipe
centerline and wall should be greater than 0.5 m(20”).
If it is less, first connect all cables to terminals in the
connection compartment (power supply and outputs)
and run them via an intermediate connection box (see
also Section 3) before installing the flowmeter.
6. Orientation
Turn the display board through ±90° or 180° to
obtain horizontal positioning of the display.
·
·
·
·
·
Turn the signal converter housing through ±90°
should that be more suitable for the location of the
installation.
7. State
of
Medium
Ensure single phase flow. Liquid droplets in gas/
vapour, solid particles in gas/liquid & gas bubbles
in liquid are not permitted.
In Liquid application e.g. water, to prevent
cavitation, minimum D/S pressure is given by the
relation:
Pds(bar _g)
>
=(2.9*DP) + (1.3*Ps)-1.013
where
DP= pr. drop of VFM in Bar from sizing program
Ps=Sat.pr. in Bar at op.temp.
In case of steam or compressed gas, a moisture
separator may be used 50D upstream of the meter
if the dryness fraction is less than 95%.
For any fluid, a filter or strainer may be used to
remove solid particles. This is specially important
for meter sizes below 1” where a filter or strainer
is a must.
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