Filter
Top Products
Reference Manual
IP2013, Rev BA
February 2012
Mobrey MSP422
3-4
Figure 3-1. Min And Max
Distances From Tank Wall
Liquid Surface
Conditions
Guidelines:
a) Foaming liquids can reduce the size of the returned echo because foam is
a poor ultrasonic reflector. Mount an ultrasonic transmitter over an area of
clear liquid, such as near the inlet to a tank or well. In extreme conditions,
or where this is not possible, the transmitter may be mounted in a vented
stilling tube provided that the inside measurement of the stilling tube is at
least 4 in. (100 mm) and is smooth and free from joints or protrusions. It is
important that the bottom of the stilling tube stays covered to prevent the
ingress of foams.
b) Avoid mounting the transmitter directly over any inlet stream.
In-tank Effects Guidelines:
a) Stirrers or agitators can cause a vortex. Mount the transmitter off-center of
any vortex to maximize the return echo.
b) If stirrer blades become uncovered, they create echoes as they pass
through the ultrasonic beam. The transmitter can learn to ignore these
false echoes (see "Learn About Echoes From False Targets" on
page 4-10).
c) In tanks with rounded or conical bottoms, mount the transmitter off-center.
If needed, a perforated reflector plate can be installed on the tank bottom
directly under the transmitter center line to ensure a satisfactory return
echo.
d) Avoid detecting pump casings, as the liquid falls away, by not mounting
the transmitter directly above pumps. If this is not possible, fine-tuning of
the transmitter on-site may be required.
Max. 3°
C
Use Non-metallic
Fitting / Flange
C =1.3 in./ft. (11 cm/m)
C Min. = 12 in. (0,3 m)
6° Beam
Half Angle