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7.2.5 Heavy soiling
If the medium is highly polluted, there is the risk that a bridge forms between the
probe and the tank wall or structures in the tank.
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Increase minimum distances depending on the pollution intensity.
7.2.6 Heavy foam build-up and turbulence
Heavy foam build-up and turbulence may lead to incorrect measurements.
To prevent this
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Install the sensor in a steady area.
Examples how to create a steady area:
• Use of a coaxial probe (only for clean, low-viscosity media)
• Installation in bypass or still pipe (Fig. 7-6)
• Separation of the installation location by metal sheets / perforated sheets
(without figure)
Fig. 7-6
d
d
A
B
C
D
d: minimum diameter (→ 7.2.2)
The upper access to the steady area (A, B) must be above the max. level.
The lower access (C, D) or the area with perforated sheet must be below
the min. level. This ensures that neither foam nor turbulence impact the
sensor zone. When perforated sheets or similar are used, soiling (e.g.
solids in the medium) can also be avoided.
