2
CHOOSING THE SENSOR LOCATION
(See Figure 2)
1) Pipe/Chute Material
- Microwave energy is contained and
channeled by metallic pipes or chutes. Internal reflections with-
in the line enhance the sensitivity of sensor. As the diameter of
the pipe/chute increases, the sensitivity of the sensor decreases.
When possible it is desirable to mount the sensor to a metallic
line to take advantage of the enhanced sensitivity. For non-
metallic pipes such as glass, plastics and concrete, material is
not as easily sensed so increased sensitivity must be set on the
electronics. However, since microwave energy can propagate
through non-metallic material, the sensor can be mounted to be
truly non-contact.
2) Material Flow Tendencies
- Select a mounting location
where the process seal will be exposed to the full motion of the
process material under normal flow conditions. The SFD-2 has
the greatest sensitivity when the material being detected is either
coming toward or going away from the process seal. When pos-
sible, mount the sensor to take advantage of this phenomena.
Many applications will be satisfied without this type of mounting.
However, if the application poses sensitivity concerns, mounting
the sensor less than 90 degrees to material flow is recommend-
ed; refer to the Calibration section which describes sensitivity.
Avoid locations where substantial product buildup can occur. In
applications where material coating occurs, position the sensor
to take advantage of any cleaning action provided by normal
flow.
3) System Movements
- The electronic circuitry has been
designed to be relatively insensitive to slow movements com-
monly associated with augers/conveyors. However, for best
operation, position sensor away from such mechanical move-
ments. When sensing through non-metallic materials, the ener-
gy can travel through the pipe/chute to the backside of the instal-
lation. The sensor must be positioned to avoid having motion of
nearby equipment or personnel interpreted as a flow condition.
Backing the non-metallic pipe/chute with a metallic shield will
greatly reduce the possibility of false signals.
Figure 1
Figure 2
SENSOR MOUNTING
Coupling Mount
- (See Figure 3) The SFD-2 sensor housing
incorporates an aluminum 1 1/4" NPT connection. The connec-
tion is specially machined to provide flush mount installation
when installed into a standard 1 1/4" half coupling. After select-
ing the appropriate location, cut a 1 1/2" diameter hole within the
pipe/chute. Position/center a 1 1/4" half coupling over the hole
and weld into place. Prior to sensor installation, prepare the
mounting threads with Teflon
®
tape or pipe dope to insure seal-
ing. Tighten the sensor into place insuring the conduit connection
is facing downward.
MECHANICAL INSTALLATION
internal controls and where indicators can be clearly seen. The
sensor and power supply/conditioner can be separated up to
2500 feet (See Electrical Installation section).