Siemens SITRANS LG250 Operating Instructions Manual page 17

PBD-51041388
When the SITRANS LG250 is used in bypass tubes, contact with the
tube wall must be avoided. We recommend for this purpose a cable
probe with centering weight.
Caution:
When mounting, make sure that the cable is straight over its entire
length. A kink in the cable can cause measurement errors and contact
with the tube.
With rod probes, a spacer is generally not required. However, if there
is a risk of the rod probe being pressed against the tube wall by in-
flowing medium, you should mount a spacer at the probe end to avoid
contact with the tube wall. In the case of cable probes, the cable can
be strained.
Keep in mind that buildup can form on the spacers. Strong buildup
can influence the measurement.
Fig. 9: Mounting in a bypass tube - Position of the spacer or the centering weight
1 Rod probe with spacer (PEEK)
2 Cable probe with centering weight
3 Spacer (PEEK) on the gravity weight of a cable probe
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.
SITRANS LG250 - Operating Instructions
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