Fig. 13: Intensely stirred surface
!
Fig. 10: Prevention to avoid
intrusion of humidity
Fig. 9: Solar radiation shielding cover
The level meter must not be installed in places
•
with direct
solar radiation
and must be protected
against weather effects.
If the installation in places with direct solar ra-
•
diation is inevitable, it is necessary to mount
a
shielding cover
above the level meter.
It is suitable to run the cable under a cable bush-
•
ing (obliquely down in slack) according to Fig. 10
to prevent
penetration of humidity
. Then the
rain and condensing water can
fl
ow off freely.
The cable bushing and connector have to be
•
suf-
fi
ciently tightened
to prevent penetration of hu-
midity.
To lower the minimum distance to the measured
•
medium,
a re
fl
ection board
made from solid,
even and smooth material can be installed to the
level meter. Then the tank can be
fi
lled nearly up
to the maximum height. The solution is suitable
for open tanks and reservoirs.
Scattering or attenuation of the ultrasonic signal
•
can result if the surface level has been
moder-
ately stirred
or
rippled
(by a mixer, coming liq-
uid etc.). It can result in reduction of the meas-
urement range or unreliable function of the level
meter (Fig. 12).
Rotating mixer blades can cause
•
that the sur-
face is stirred, which results in false re
fl
ections of
the ultrasonic signal from the surface level and
unreliable operation of the level meter (Fig. 13).
Fig. 12: Moderately stirred surface
Fig. 11: Re
fl
ection board
H + L = Dead zone
www.jetec.com.tw
久德電子
TEL:
+886-4-23729418
FAX:
+886-4-23724011
(40349)
台中市西區福人街11號
