VEGA VEGAPULS 43 Profibus PA - Manual (Page 17)

VEGAPULS 43 – Profibus PA 17
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
The flange screws of VEGAPULS 43 must
always be tightened with a torque of approx.
60 Nm so that the PTFE seal is tight.
Dished tank tops can act as paraboloidal
reflectors. If the radar sensor is placed in the
focal point of the parabolic tank top, the radar
sensor receives amplified false echoes. The
radar sensor should be mounted outside the
focal point. Parabolically amplified echoes are
thereby avoided.
Horn antenna directly on the vessel top
If the stability of the vessel will allow it (sensor
weight), flat mounting directly on the vessel
top is a good and cost-effective solution. The
top side of the vessel is the reference plane.