VEGA VEGAFLEX 63 4 … 20 mA_HART two-wire - Manual (Page 13)

T
o compensate the normal bias voltage loss due to the seal materials,
you have to use also disc springs in addition to the flange screws for
fastening PTFE plated flanges.
T
he flange screws of VEGAFLEX 63 must always be tightened with a
torque of approx. 60 Nm (44 lbf ft) so that the PTFE washer seals
reliably.
I f possible, avoid sockets. Mount the sensor flush with the vessel top. If
this is not possible, use short sockets with small diameter.
H igher sockets or sockets with a bigger diameter can generally be
used. They simply increase the upper dead band. Check if this is
relevant for your measurement.
I n such cases, always carry out a gating out of false signals after
installation. You can find further information under "Setup procedure".
I f a socket is absolutely necessary, then the use of a coax probe is
recommended. Due to the coax guide tube, sockets do not influence
measurement accuracy.
h
d
d h
DN40 ... DN150 ≤ 150 mm ( 7 29 /
32
")
≤ 100 ( 3 15 /
16
") > DN150 ... DN200
Fig. 4: Mounting socket
S tandpipes or bypass tubes are normally metal tubes with a diameter
of 30 … 200 mm (1.18 … 7.87 in). In measurement technology such a
tube corresponds to a coax probe. It does not matter if the standpipe is
perforated or slotted for better mixing. Lateral inlets with bypass tubes
also do not influence the measurement.
M easuring probes can be mounted in bypass tubes up to DN 200.
I f VEGAFLEX 63 is used in standpipes or bypass tubes, contact with
the tube wall should be avoided. We offer spacers as accessories for
fastening the probe in the middle of the tube.
Torque with PTFE plated
flanges
Socket
Standpipes or bypass
tubes
VEGAFLEX 63 • 4 … 20 mA/HART two-wire 13
4 M ounting
31841
-
EN
-100426