User Manual

INSTALLATION 3
31
OPTIWAVE 7400-24 C
www.krohne.com12/2015 - 4004901901 - MA OPTIWAVE7400-24 R01 fr
3.7.5 Standpipes (stilling wells and bypass chambers)
Use a standpipe if:
• There is highly conductive foam in the tank.
• The liquid is very turbulent or agitated.
• There are too many other objects in the tank.
• The device is measuring a liquid (petro-chemicals) in a tank with a floating roof.
• The device is installed in a horizontal cylindrical tank (refer to the end of this section)
Stilling wells - general notes
Installation in tanks containing one liquid and foam
• Drill an air circulation hole (max. Ø10 mm / 0.4¨) in the stilling well above the maximum level.
• Remove the burr from the hole.
Installation in tanks containing one liquid or more without foam
• Drill an air circulation hole (max. Ø10 mm / 0.4¨) in the stilling well above the maximum level.
Figure 3-12: Installation recommendations for standpipes (stilling wells and bypass chambers)
1 A stilling well solution
2 A bypass chamber solution
3 Air circulation hole
4 Level of the liquid
CAUTION!
• The standpipe must be electrically conductive.
• The inside diameter of the standpipe must not be more than 5 mm / 0.2 ¨ over the diameter of
the antenna (for a high-dielectric constant liquid).
• The standpipe must be straight. There must be no sudden changes in internal diameter
greater than 1 mm / 0.04
¨ .
• The standpipe must be vertical.
• Recommended surface roughness: < ± 0.1 mm / 0.004 ¨ .
• Make sure that there are no deposits at the bottom of the standpipe.
• Make sure that there is liquid in the standpipe.