4210 Flow Meter
Section 3 Installation
3-10
Note
In open channel installations, where flow may exceed one-half
of full pipe, you must place the transducer as close as possible
to the midpoint between the pipe entrance and exit of the
U-Channel to ensure sensing over the least turbulent flow.
3.6.2 Dead Band Mount the ultrasonic level sensor as close to the maximum
expected level as possible. This minimizes many of the unde-
sirable characteristics of ultrasonic distance measurement.
However, you must mount the ultrasonic level sensor at least two
foot higher than the maximum expected level. This is a result of
the two foot dead band directly below the level sensor where no
measurements can be taken.
3.6.3 Accidental Submersion Since both ends of the ultrasonic level sensor are completely
sealed, temporary submersion in the flow stream should not
cause any harm, if that should accidentally happen. However,
you should avoid prolonged submersion. You should also realize
that submersion will keep the level sensor from working, even if
it is not damaged. Prolonged submersion or submersion in dirty
or greasy flow streams may cause the surface of the transducer
to become coated with solid matter. This could cause it to mal-
function until it is cleaned. If possible, mount the ultrasonic level
sensor high enough above the flow stream to avoid submersion
under normal circumstances.
3.6.4 Mounting the Sensor You can mount the ultrasonic level sensor over the flow stream in
various ways. It is up to you to determine which method best fits
the application. Mounting examples are shown in the illustra-
tions. The ultrasonic level sensor has a
3
/4" male pipe thread with
a conduit lock nut to connect it to a mounting bracket or cable
stiffener. An optional mounting bracket is available from Isco to
mount the ultrasonic level sensor. You can also run the ultrasonic
level sensor cable through conduit to the flow meter.
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