ADS Environmental Services IETG FlowHawk QR 775012 A4 - Manual (Page 50)

2-14 IETG FlowHawk Manual
Sensors
The FlowHawk flow monitor can support up to 2 of the 4 sensor
types available (3 combination sensors and a stand-alone ultrasonic
depth sensor) at one time to gather raw flow data. It also can
support 2 of the same sensor type at one time. Using independent
measurement techniques, ultrasonic and pressure depth sensors
collect information used to determine the depth of the flow.
Velocity sensors use Doppler technology to determine the average
or peak velocity of the flow. This variety of sensor options
provides the versatility of measuring the depth and velocity of the
flow from the top or bottom of the pipe and/or from within or
outside of the flow.
A sewer system's hydraulics are much more stable and uniform in
the incoming pipe than in the manhole invert or outgoing pipe.
Therefore, the sensors mount to a stainless steel expandable ring or
stainless steel bands installed in the pipe upstream from the
manhole. Installing them upstream minimizes the hydraulic effects
and erroneous data readings caused by foamy waters, flow waves,
sewer noise, non-laminar flow, and obstructions in the manhole.
Peak Combo Sensor
The Peak Combo Sensor with a standard 10.6-meter (35-ft) or 30.5-
meter (100-ft) cable (p/n 8K-CS4-XX-35/1H) typically mounts at
the bottom of the pipe and measures ultrasonic depth, pressure
depth, and peak velocity using three independent sensors.