VEGA VEGAPULS 45 4 … 20 mA; HART compact sensor - Manual (Page 20)

20 VEGAPULS 42, 44 and 45 – 4 … 20 mA
ø50
> 300 mm
Tube antenna system with ball valve cutoff in measur-
ing tube
Ball valve
Vent hole
Deflector
Surge pipe with ball valve
If a ball valve is mounted in the surge pipe,
maintenance and servicing can be carried
out without opening the vessel (e.g. if it con-
tains liquid gas or toxic products).
A prerequisite for trouble-free operation is a
ball valve throat that corresponds to the pipe
diameter. The valve must not have rough
edges or narrow areas in its channel. The
distance to the sensor flange should be at
least 300 mm.
Mounting and installation
If you want to measure inhomogeneous or
stratified products in a surge pipe, it must
have holes, elongated holes or slots. These
openings ensure that the liquid is mixed and
corresponds to the liquid in the vessel.
The more inhomogeneous the measured
product, the closer the openings should be
spaced.
Due to radar signal polarisation, the holes or
slots must be positioned in two rows offset
by 180°. The radar sensor must then be
mounted so that the type label of the sensor
is aligned with the rows of holes.
Every wider slot causes a false echo. The
slots should therefore not exceed a width of
10 mm in order to keep the signal noise level
to a minimum. Round slot ends are better
than rectangular ones.
ø 5...15
VEGAPULS 44: Row of holes in one axis with the type
label
Type label