VEGA VEGAVIB 31-53 - Manual (Page 14)

14 VEGAVIB
Mounting
Handling
The vibrating level switch is a measuring instru-
ment and must be treated accordingly. Bending
the vibrating element will destroy the instrument.
Lock fitting
Lock fittings are available for VEGAVIB 43 and
VEGAVIB 53 for infinitely variable height adjust-
ment. Be aware that VEGAVIB 53 level switches
in conjunction with a lock fitting must not be
used in pressurized vessels. VEGAVIB 43 can
be used in vessels with up to 4 bar pressure.
Tensile load
When using the cable version, make sure that
the max. permissible tensile load of 6000 N is
not exceeded. This can occur mainly with very
heavy solids and large measuring lengths.
Buildup
With VEGAVIB 31, the surfaces of the tuning
fork should be vertical in order to reduce
buildup. The orientation of a tuning fork is
marked on the hexagon of VEGAVIB. With it you
can check the position of the tuning fork. When
the hexagon touches the seal, the thread can
still be turned by approx. half a turn. This is
sufficient to reach the recommended installation
position.
If the granulation size of the solid is larger than
the min. distance between the tuning fork
blades (8 mm), product particles can wedge
themselves in the tuning fork and trigger a
malfunction. In this case, series 40 or 50 vibrat-
ing level switches should be used.
Moisture
Turn the cable entry of the instrument down-
wards (after installation) to avoid moisture in-
gress. For this purpose, the housing can be
rotated by approx. 330°. With vertically installed
instruments, loop the cable to the instrument
housing downwards so that rain or condensa-
tion water can drain off (see fig. 2.3).
Material cone
When planning the location of the vibrating rod
in the vessel, be aware that in solids, material
cones can form which can change the switch-
ing point. We recommend selecting an installa-
tion location where the vibrating rod detects an
average value of the material cone. The mount-
ing location of the vibrating rod must take the
location of the filling and emptying apertures of
the vessel into account. To compensate meas-
urement errors caused by the material cone in
cylindrical tanks, the vibrating rod must be
mounted at a distance of
d /
6
from the vessel
wall. Here, a min. distance of approx. 40 cm
must be maintained (see fig. 2.4).
Fig. 2.3
Pressure
When there is gauge pressure or underpressure
in the vessel, the mounting boss must be sealed
on the thread. Cover the thread with teflon tape,
hemp or a similar material or use a sufficiently
resistant seal ring.