Special Installation Situations - Endress+Hauser Levelflex FMP55 Operating Instructions Manual

Mounting
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6.1.7

Special installation situations

Bypasses and stilling wells
The use of centering disks/stars/weights (available as accessories) is recommended in
bypass and stilling well applications.
As the measuring signal penetrates many plastics, installation in plastic bypasses or
stilling wells can produce incorrect results. For this reason use a metal bypass or
stilling well.
1 Mounting in stilling well
2 Mounting in bypass
3 Minimum distance between probe end and lower edge of bypass 10 mm (0.4 in)
• Pipe diameter: > 40 mm (1.6 in) (for rod probes).
• A rod probe can be installed in pipes with a diameter of up to 150 mm (6 in). The use of
a coax probe is recommended for larger pipe diameters.
• Side outlets, holes, slots and welds - with a maximum inward projection of 5 mm (0.2 in)
- do not affect the measurement.
• There should not be any changes in the diameter of the pipe.
• The probe must be 100 mm (4 in) longer than the lower outlet.
• The probes must not touch the pipe wall within the measuring range. Support or brace
the probe if necessary. All rope probes are prepared for bracing in vessels (tensioning
weight with anchor hole).
• The probes must not touch the pipe wall within the measuring range. If necessary, use a
PFA centering star.
• Coax probes can be used within any restrictions provided that the pipe diameter permits
their installation.
For bypasses with condensate formation (water) and a medium with a low dielectric
constant (e.g. hydrocarbons):
Over time, the bypass fills with condensate up to the lower outlet. When levels are
low, the level echo is masked by the echo of the condensate as a result. In this range,
the level of the condensate is output and the correct value is only output when levels
are higher. For this reason, ensure that the lower outlet is 100 mm (4 in) below the
lowest level to be measured and fit a metal centering disk at the level of the lower
edge of the lower outlet.
In thermally insulated vessels, the bypass should also be insulated in order to prevent
condensate formation.
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Levelflex FMP55 PROFIBUS PA
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Endress+Hauser
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