19
4 Mounting
VEGAFLEX 86 • 4 … 20 mA/HART - two-wire
49477-EN-150102
1
2
h
Fig. 9: Mounting in a bypass tube - Position of the spacer or the centering weight
1 Rod probe with spacer (steel)
2 Cable probe with centering weight
h Measurable tube section
Note:
Measurement in a standpipe is not recommended for extremely adhe-
sive products. In case of slight buildup, you should choose a bypass
tube with bigger diameter.
Instructions for the measurement:
•
The 100 % point with bypass tubes should be below the upper
tube connection to the vessel.
•
The 0 % point with bypass tubes should be above the lower tube
connection to the vessel.
•
A false signal suppression with installed sensor is generally rec-
ommended to achieve maximum possible accuracy.
Standpipes or surge pipes are normally metal tubes with a diameter
of 30 … 200 mm (1.18 … 7.87 in). Up to a diameter of 80 mm (3.15
in), such a pipe corresponds to a coax measuring probe. It does not
matter if the standpipe is perforated or slotted for better mixing.
Measuring probes can be mounted in standpipes up to DN 200.
For standpipes, select the probe length such that the blocking dis-
tance (dead band) of the probe is above the tube end or below the
upper filling hole. This allows you to measure the total level range of
the medium in the standpipe. When designing the standpipe, keep the
blocking distance of the probe in mind and plan the length above the
upper lateral filling opening accordingly.
Standpipes