Endress+Hauser Levelflex FMP51 Operating Instructions Manual page 38

Mounting
38
• Pipe diameter: > 40 mm (1.6") for rod probes
• Rod probe installation can take place up to a diameter size of 150 mm (6 in). In the
event of larger diameters, a coax probe is recommended.
• Side disposals, holes or slits and welded joints that protrude up to approx. 5 mm (0.2")
inwards do not influence the measurement.
• The pipe may not exhibit any steps in diameter.
• The probe must be 100 mm longer than the lower disposal.
• Within the measuring range, the probe must not get into contact with the pipe wall. If
necessary, secure the probe by retaining or tensioning. All rope probes are prepared for
tensioning in containers (tensioning weight with anchor hole).
• If a metallic center washer is mounted at the end of the probe, it enables a reliable
recognition of the end-of-probe signal (see feature 610 of the product structure).
Note: For interface measurements only use the nonmetallic centering star made of PEEK
or PFA (feature 610, options OD or OE).
The center washer or spacer is also available as an accessory: →  136.
• Coax probes can always be applied if there is enough mounting space.
For bypasses with condensate formation (water) and a medium with low dielectric
constant (e.g. hydrocarbons):
In the course of time the bypass is filled with condensate up to the lower disposal and
for low levels the the level echo is superimposed by the condensate echo. Thus in this
range the condensate level is measured instead of the correct level. Only higher levels
are measured correctly. To prevent this, position the lower disposal 100 mm (4 in)
below the lowest level to be measured and apply a metallic centering disk at the
height of the lower edge of the lower disposal.
With heat insulated tanks the bypass should also be insulated in order to prevent
condensate formation.
For information on bypass solutions from Endress+Hauser please contact your
Endress+Hauser sales representative.
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