KROHNE VFM 1091 I Installation And Operating Instructions Manual page 5

EXPANDER
REDUCER
FLOW STRAIGHTENER
SPACIAL FLOW STRAIGHTENER
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 straightener must always be 12 D.
The small sizes (below 1" or DN 25) come with upstream &
downstream pipelines & flange connections to suit customer's flanges.
4. 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 & bluffbody axis.
SANDWICH VERSION
Flexible pipes or bellows may be used before the upstream and after the
downstream in case the vibrations are too high. Pipe vibration limit is
0.2 g peak to peak up to 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.
Do not lag (Thermally insulate) the meter body.
6. Orientation
• Turn the Display board through ±90 or 180 to obtain horizontal
positioning of the display.
• Turn the signal converter housing through ±90
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
FLANGED VERSION
0 0
or 180 should that
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