ADS Environmental Services FlowShark Pulse QR 775004 A1 - Manual (Page 51)

6-6 ADS FlowShark Pulse O&M Manual
Sensor Installation and Connection
Choosing a Suitable Location for Sensor Installation
Clear and stable hydraulic conditions are essential for obtaining accurate sensor
measurements. Therefore, consider the following when inspecting the physical and
hydraulic conditions at all potential installation locations:
z Strictly avoid locations experiencing or near draw-downs, steps, curves,
obstructions, pipe joints, profile changes, or immediately upstream or
downstream of inlet or lateral connections.
z Choose a location where sedimentation (sand, grit, sludge, etc.) does not
develop under normal flow conditions. Sedimentation can accumulate due to
friction in pipes at locations exhibiting minimal or negative slope or structural
deficiencies that create obstructions or pockets. Typically, channels that
regularly exhibit flow velocities of more than 2 feet per second will not
experience a buildup of sediment.
z Avoid measuring flow depth in closed pipes that remain at least 80 percent
full under normal flow conditions. These sites can fill up completely during
elevated or peak flows, potentially resulting in backup or surcharge
conditions.
z Avoid locations that exhibit significant changes in slopes.
z In general, make sure the distance of the upstream approach to the sensor is 5
times the approximate diameter of the pipe and the distance downstream from
the sensor is 2 times the approximate diameter of the pipe. However, consider
longer straight approaches when turbulent hydraulic conditions generate
distorted flow profiles.
The following figures provide examples of appropriate and problematic sensor
installations. Please forward any applicable drawings/photos and contact your ADS
representative for assistance in selecting an appropriate location or in assessing
potential locations to install sensors for accurate flow measurements.
Figure 6-3 Sensor Adjustment: (left) proper installation in center that should yield reliable measurements; (right)
faulty installation that will yield erroneous measurements