User Manual

VEGAPULS 42 and 44 – 4 … 20 mA 39
100 %
0 %
> 300 mm
Mounting and installation
Tube flange system as bypass tube
Extended bypass tube on a vessel with turbulent
product movements
Type label
75 %
0 %
100 %
> 300 mm
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 stabler
measurement with this alignment.
When mounting the sensor on a bypass 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.
100 %
0 %
> 300 mm
300 ... 800 mm
Tube flange system as bypass tube
Type label
For products with small dielectric constants
(< 4), a much longer bypass tube should be
used than required by the lower tube con-
nection. Products with small dielectric con-
stants are partly penetrated by the radar
signals, so that the tube bottom delivers a
stronger echo than the product (when the
bypass tube is nearly empty). Due to the
extension of the lower tube end, sufficient
liquid will remain even when the vessel is
emptied.