2150EX AV Flow Module - Isco

2150EX Area Velocity Flow System
Section 2 Preparation and Installation
2.2.2 Locating the Site The 2150EX is designed to measure flow in open channels with
or without a primary device. A primary device is a hydraulic
structure, such as a weir or a flume that modifies a channel so
there is a known relationship between the liquid level and the
flow rate. Although the 2150EX supports flow rate conversion in
channels with a primary device, its level and velocity measurement
capabilities are best suited for channels without a
primary device.
Note
Primary devices limit the usefulness of the AV Sensor’s readings.
In most cases, levels and velocities near these structures
do not represent what normally occurs in the channel. If you
must use area velocity flow conversion, or if your interest is the
stream’s velocity, do not install the AV Sensor near a primary
device. Move the AV Sensor away to where the flow is unaffected
by the primary device.
2.2.3 Channels Without a
Primary Device
2.2.4 Channels With a
Primary Device
When the AV Sensor is installed without a primary device, find a
section of channel with a minimum of disturbances to the flow.
Avoid areas with elbows, outfalls, inverts, junctions, etc. that
create turbulence near the AV Sensor. The AV Sensor should be
located away from these disturbances to a point where the flow
has stabilized. For best results, install the AV Sensor where the
flow is most uniform. Uniform flow is a condition where the
water surface is parallel to the bottom of the channel.
If the AV Sensor is installed in a primary device, its location
depends on the type of primary device. Most primary devices
have a specific place for the head (level) measurement sensor. For
more details about the location of the head measuring point,
refer to the Isco Open Channel Flow Measurement Handbook, or
to information provided by the manufacturer of the primary
device.
Note
When you install the AV Sensor for use within a primary
device, a Level-to-Flow conversion method should be used.
(See Programming, Section 3.)
2.2.5 2150EX and AV Sensor
Mounting
Considerations
Ideal sites are easily accessible for service and data collection,
while still providing protection for the 2150EX module devices.
The 2150EX module devices are rated NEMA 4X, 6P, and constructed
of materials that can withstand harsh environments.
However, continual exposure to UV light, or periodic submersion
should be avoided to extend the life of the components.
Typically, the 2150EX is suspended inside a manhole. Suspending
the 2150EX near the opening will protect it from the elements,
minimize the chance of submersion, and allow it to be
easily retrieved without entering the manhole.
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