VEGA VEGAPULS 51K…54K 4 … 20 mA; HART compact sensor - Manual (Page 16)

16 VEGAPULS 51K … 54K
21750-EN-031222
Welding beads too large
Tube connection protrudes
Additional connection in the bypass tube in one plane
Adhesive products
With adhesive products, a surge pipe with a
larger inner diameter should be used. For
non-adhesive products, the best and most
inexpensive solution is a measurement tube
with a diameter of 50 mm. For slightly adhe-
sive products, use a surge pipe with a nomi-
nal diameter of 100 mm or 150 mm to prevent
buildup from causing measurement errors.
Measurement of extremely adhesive prod-
ucts in a standpipe is not possible.
Mounting and installation
If enough liquid (300 … 800 mm) remains in
the blind lower end of the tube, the portion of
the signal that penetrates the liquid and re-
flects from the tube bottom is sufficiently
damped - the sensor can then easily distin-
guish it from the echo of the liquid surface. In
cases where there is not enough liquid at the
bottom of the tube, a deflector situated there
will carry out the same function. It deflects
signals that reach the tube bottom into the
standard connection opening.
Connections to the bypass tube
The connections to the bypass tubes must
be fashioned in such a way that only minimal
reflections are caused by the walls of the
connecting tubes. This is especially important
for the breather connection in the upper part
of the tube. Observe the following points:
• Use small openings for the connection.
• The diameter of the connecting tubes
should not exceed 1/3 of the bypass diam-
eter.
• The tube connections must not protrude
into the bypass.
• Large welding beads in the tubes should
be avoided.
• Additional connections to the bypass tube
must lie in the same plane as the upper
and lower vessel connection (above each
other or displaced by 180°).
Optimum connection to the bypass tube