VEGA VEGASCAN 850 - Manual (Page 47)

VEGASCAN 850 47
Vessel installations
Vessel installations such as, for example, a
ladder, often cause false echoes. Make sure
when planning your measurement loop that
the ultrasonic signals have free access to the
measured product.
Vessel installations
Correct Wrong
Ladder
Ladder
Struts
Struts, like other vessel installations, can
cause strong false echoes that are superim-
posed over the useful echo signals. Small
shields effectively hinder a direct false echo
reflection. These false echoes are scattered
and diffused in the area and are then filtered
out as "echo noise“ by the measuring elec-
tronics.
Struts
Correct Wrong
Shields
4.7 False echoes
The mounting location of the ultrasonic sensor
must be selected such that no installations or
inflowing material are in the path of the ultra-
sonic impulses. The following examples and
instructions show the most frequent measur-
ing problems and how to avoid them.
Vessel protrusions
Vessel forms with flat protrusions can, due to
their strong false echoes, adversely effect
the measurement. Shields above these flat
protrusions scatter the false echoes and
guarantee a reliable measurement.
Intake pipes, e.g. for the mixing of materials -
with a flat surface directed towards the sen-
sor - should be covered with a sloping
shield. This shield will scatter false echoes.
Vessel protrusions (intake pipe)
Correct Wrong
Vessel protrusions (slope)
Correct Wrong
Mounting and installation