VEGA Capacitive electrodes EK 4 … 20 mA - Compact - Manual (Page 18)

18 Capacitive electrodes EK 4 … 20 mA - Compact
22574-EN-020809
L
Fixing weight
With measuring probes that deliver continuous
measured values, the electrode must be in-
stalled vertically. If installation from the top is
not possible, the electrodes can also be
mounted laterally (fig. 2.5).
Under accessories in our price list, you can
find a screening tube and a closing cone or an
angled rod electrode with which the instrument
can also be laterally mounted. Determine a
screening tube length (L) that will not allow
product bridges to form between cable and
vessel wall, and that will not allow the electrode
cable to touch the vessel wall. Use a fixing
weight or a fixing insulator.
Fig. 2.5 Continuous electrodes
Fig. 2.4 Cable electrode in solids
Mounting
Non-conductive vessels
In non-conductive vessels, e.g. plastic tanks,
the second pole of the capacitor must be
provided separately, e.g. in the form of a
concentric tube.
When using a standard electrode, a suitable
grounding surface is necessary. Provide
therefore the largest possible grounding sur-
face, e.g. wire braiding laminated into the
vessel wall or metal foil glued to the vessel.
Connect the grounding surface to the ground
terminal on the housing.
Rod electrode
Mount the rod electrode such that the elec-
trode protrudes into the vessel. When mount-
ing in a tube or a socket, material buildup
which deters the measurement can form. This
is particularly the case with viscous or adhe-
sive mediums.
Cable electrodes in solids
Depending on the type of solid, the filling
method and its location, the cable electrode
may „float“ in spite of the gravity weight. The
electrode (cable) is pushed by the solid
against the vessel wall or to the surface, thus
causing incorrect measured values. This
should be avoided during continuous meas-
urement.
If this happens, use a fixing weight or insulator
to secure the cable electrode (fig. 2.4)
When securing the cable electrode, avoid high
tensile forces. An appropriate fixing spring
which prevents cable overload can be found
in our price list.
Lateral mounting