VEGA VEGAPULS 45 VBUS - Manual (Page 18)

18 VEGAPULS 42, 44 and 45 – VBUS
100 %
0 %
> 300 mm
Tube flange system as bypass tube
Type label
Make sure the required upper vent hole in
the surge pipe is aligned with the sensor
type label.
As an alternative to a surge pipe in the ves-
sel, a pipe antenna system outside the ves-
sel in a bypass tube is also possible.
The surge and bypass tubes must generally
be made of metal. For plastic tubes, a
closed, conductive jacket is always required.
For metal tubes with plastic inner coating,
make sure that the thickness of the coating is
minimal (approx. 2 … 4 mm).
Align the sensor such that the type label lies
on one axis with the tube holes or the tube
connection openings. The polarisation of the
radar signal enables a considerably more
stable measurement with this alignment.
When mounting a VEGAPULS 42 or 44 sen-
sor on a bypass tube (e.g. on a previous
floating or displacer unit), the radar sensor
should be mounted at a distance of approx.
300 mm or more from the max. level.
max max
min
min
Mounting and installation
Pipe antenna systems in the tank
Type label
Vent hole
ø 5 … 10 mm
Surge pipe welded
to the tank
Surge pipe in the
socket piece
The surge or bypass tubes open at the bot-
tom should reach to the requested min. level,
since a reliable measurement is only possible
within the pipe. The tube inner diameter
should be max. 100 mm and correspond with
the size of the antenna horn.
3.3 Measurement in standpipe
(surge or bypass tube)
General instructions
Pipe antennas are preferred in vessels which
contain many installations, e.g. heating tubes,
heat exchangers or fast-running stirrers.
Measurement is then possible where the
product surface is very turbulent, and vessel
installations cannot cause false echoes.
Through the focusing of the radar signals
within the measuring tube, even products
with low dielectric constant (
ε
r
= 1.6 to 3) can
be measured reliably in the surge or bypass
tube. Note the following instructions.
without deflector with deflector