False Echoes - Vega VEGASON 51K Operating Instruction

Mounting and installation

4.6 False echoes

The placing of the ultrasonic senor must be
chosen so as to ensure that no mountings or
in-flowing filling material crosses with the
ultrasonic impulses. The following examples
and instructions show the most frequent
measuring problems and how to avoid them.
Vessel protrusions
Vessel forms with flat protrusions can, due to
their strong false echoes, greatly effect the
measurement. The placing of shields over
these flat protrusions scatter the false echoes
and guarantee a definite measurement.
Correct
Vessel protrusions (slope)
Intake pipes, i.e. for the mixing of materials -
with the flat top turned towards the sensor -
should be covered with an angular shield
with which the false echoes are then scat-
tered.
Correct
Vessel protrusions (intake pipe)
VEGASON 51K ... 53K
Vessel mountings
Vessel mountings such as, for example, a
ladder often cause false echoes. When pro-
jecting the measuring point, please ensure
the free access of the ultrasonic signals to
the medium.
Wrong
Vessel mountings
Vessel struts
Vessel struts, as with other vessel mountings,
can cause strong false echoes which super-
impose the useful echoes. Small shields
effectively hinder a direct false echo reflec-
tion. The false echoes are scattered and
diffused in the area and are then filtered out
as "echo noise" by the measuring electronics.
Wrong
Vessel struts
Correct
Ladder
Correct
Shields
Wrong
Ladder
Wrong
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