Siemens SITRANS LG250 Operating Instructions Manual page 18

Standpipes
18
•
A false signal suppression with installed sensor is generally rec-
ommended to achieve the best 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.
3
A
2
Fig. 10: Mounting in a standpipe
1 Holes (for mixing)
2 Standpipe - vertically mounted - max. deviation 10 mm (0.4 in)
3 Ventilation opening
A Rod probe with spacer (steel)
B Cable probe with centering weight
For standpipes, select the probe length such that the upper blocking
distance (dead band) of the probe is above the upper ventilation hole.
This allows you to measure the total level range of the medium in the
standpipe. When designing the standpipe, keep the upper blocking
distance of the probe in mind and plan the length above the upper
lateral filling opening accordingly.
SITRANS LG250 - Operating Instructions
ø 150 - 200 mm
(5.91 - 7.87")
1
ø 150 - 200 mm
(5.91 - 7.87")
B
PBD-51041388