9
© Dinel, s.r.o. ULM–53
Fig. 10: Reection board
H + L = Dead zone
Fig. 12: Intensely stirred surface
!
Fig. 9: Prevention to avoid intrusion
of humidity
Fig. 8: Direct solar radiation shielding
cover
k) The level meter must not be installed in places
with direct solar radiation and must be protected
against weather conditions.
l) In case the installation at places with direct solar
radiation is inevitable, it is necessary to mount
a shielding cover above the level meter (Fig. 8).
m) If possible, insert the cable from above and let a
draining loop in order to avoid intrusion of humid-
ity (Fig. 9).
n) The cable bushing as well as the connector have
to be tightened sufciently to prevent penetra-
tion of moisture.
o) To lower the minimum distance to the medium
measured, a reection board made from solid,
even and smooth material can be installed together
with the level meter (Fig. 10). Subsequently, the
tank can be lled nearly up to the maximum vol-
ume. The solution is suitable for open tanks and
reservoirs.
p) Scattering or attenuation of the ultrasonic signal
can result if the surface level has been moderately
stirred or rippled as a consequence a stirrer’s op-
eration, inow of liquid and the like. Consequently,
measuring range or unreliable level meter’s func-
tioning might follow (Fig. 11).
q) False surface reections of the ultrasonic signal
might result as a consequence of rotating mixer’s
blades that ripple the surface level and thus cause
unreliable level meter’s functioning (Fig. 12).
r) The level meter should not be installed at places
where ultrasonic signal false reections caused
by stirrer blades might occur (Fig. 13).
!
Fig. 11: Moderately stirred
surface
Fig. 13: False reection caused by
mixer blade
