VEGA VEGAPULS 43 4 … 20 mA; HART compact sensor - Manual (Page 15)

VEGAPULS 43 – 4 … 20 mA 15
26626-EN-041227
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.
When using a metal tube with plastic inner
coating, make sure that the thickness of the
coating is minimal (approx. 2 … 4 mm).
Align the sensor so that the type label lies on
the same axis as the tube holes or the tube
connection openings. The polarisation of the
radar signals enables a considerably stabler
measurement with this alignment.
When mounting a VEGAPULS 43 on a by-
pass tube (e.g. on a previous floating or
displacer unit), the radar sensor should be
placed approx. 300 mm or more from the
max. level.
max max
min
min
Pipe antenna system in the tank
Type label
Vent hole
ø 5 … 10 mm
Surge pipe welded
to the tank Surge pipe in the
socket piece
Surge pipes which are open at the bottom
must extend over the full measuring range
(i.e. down to 0% level), as measurement is
only possible within the tube. The tube inner
diameter should be max. 100 mm or corre-
spond to the size of the antenna horn.
3.3 Measurement in standpipe
(surge or bypass tube)
General instructions
Measurement in a standpipe is preferred in
vessels which contain many installations, e.g.
heating tubes, heat exchangers or fast-run-
ning stirrers. Measurement is then possible
when the product surface is very turbulent,
and vessel installations can cause no false
echoes.
Due to the concentration of the radar signals
within the measuring tube, even products
with small dielectric constants (
ε
r
= 1.6 up to
3) can be reliably measured in surge or by-
pass tubes.
without deflector with deflector
Mounting and installation