VEGA Capacitive electrodes EK 4 … 20 mA - Compact - Manual (Page 16)

16 Capacitive electrodes EK 4 … 20 mA - Compact
22574-EN-020809
Mounting
Fig. 2.1 Lateral load
2 Mounting
2.1 Mounting instructions
General
Different mediums and measurement require-
ments make different installation positions
necessary. Please note the following points.
Lateral load
Make sure that the electrode is not subjected
to strong lateral forces. Mount the electrode in
a position in the vessel where no disturbing
factors, e.g. stirrers, filling openings etc. are
present. This is especially important for very
long rod and cable electrodes.
Pressure
If there is gauge pressure or underpressure
in the vessel, the mounting boss on the thread
must be sealed. Use the attached seal ring.
Check whether the seal ring is resistant
against the medium.
Insulating measures, such as e.g., covering
the thread with Teflon tape, can obstruct the
necessary electrical connection. in such
cases, make sure the instrument has a
ground connection to the vessel.
Shortening the electrode
Fully insulated electrodes have fixed dimen-
sions which must not be modified in any way.
Any modification will destroy the instrument.
Partly insulated cable or rod electrodes can
be shortened if necessary. The basic capaci-
tance of the electrodes is compensated auto-
matically at adjustment time. Because of this,
the electrodes can be shortened by any de-
sired amount.
Cable electrode EK 31 can also be shortened
(see fig. 2.2). Loosen the two pins on the
gravity weight (hexagon socket) and remove
them. Pull the cable out of the gravity weight.
To avoid fraying the steel cable (EK 31) during
cutting, you must tin the cable around the
cutting position with a soldering iron or
blowtorch, or tightly wrap the cable with a
wire. Shorten the electrode cable with a metal
cutting saw or a cutting-off wheel by the re-
quested length.
Carry out an adjustment. The instruction is
under „4.1 Adjustment“.
Downward forces
Strong downward forces, e.g. due to sudden
material inflow or material slide, can cause
high tensile loads.
In such cases, use a rod electrode for short
meas. distances, because a rod is usually
more stable. If, due to the length or the instal-
lation position, a cable electrode is necessary,
the electrode should not be fixed but simply
provided with a gravity weight to allow the
cable to more easily follow the product move-
ments. Make sure that the electrode cable
does not touch the vessel wall.