51-616 Echotel Model 350/351 Ultrasonic Non-Contact Level Transmitter
2
1.2.2 General Unit Mounting Requirements
1. Make sure that there are no obstructions between the face
of the sensor and the liquid level. Ultrasonic energy radi-
ates from the sensor face in a cone-shaped beam of approx-
imately 12° width (diameter). Any object within the sig-
nal's path may produce an echo that can mask the true
echo returned by the liquid surface.
2. Position the sensor so that the radiating surface or sensor
face is exactly parallel to the target surface. This will pro-
vide the strongest return signals and enhance the reliability
of the 350/351.
3. In applications where the material level can reach the top
of the tank, the sensor portion of the unit must be mount-
ed in a short, flanged standpipe. The diameter of the
standpipe should be at least 8 inches (203 mm) and its
length should be limited to 12 inches (305 mm). Refer to
Figure 2.
4. Avoid installing the sensor in tank top openings that
exhaust heated air or vapors. The boundaries between the
vapors and the outside air often represent acoustic imped-
ance gradients that can cause troublesome sound reflec-
tions. In those installations, the sensor should be mounted
well away from the opening inside the tank, or in a stand-
pipe as illustrated here. Refer to Figure 3.
1.2.3 Remote Transmitter Mounting Procedure
Remote mount Model 351 transmitters should be mounted
in a location that permits easy access for maintenance.
Avoid locations that are exposed to direct sunlight, flood-
ing, high levels of radiated electromagnetic interference,
and excessive vibration or shock.
1. Mount the enclosure to a wall or flat surface using appro-
priate screws or bolts. A remote mounting bracket is avail-
able from the factory, if required. Refer to mounting hole
pattern as shown in the dimensional drawing on page 18.
2. Provide watertight seals for all wiring entrances into the
enclosure.
3. Install conduit for power and control wiring. Be sure
all connections to the enclosure maintain the proper
NEMA rating.
4. Be sure to replace housing cover before proceeding to
sensor mounting.
Figure 2
Sensor Mounting in Standpipes
8" (203)
Minimum I.D.
2" NPT
Transducer
This end
welded
or flanged
Standpipe
Maximum 12"
(305 mm) or less
Figure 3
Sensor Mounting for Tanks with Exhaust
