ADS Environmental Services IETG FlowHawk QR 775012 A4 - Manual (Page 52)

2-16 IETG FlowHawk Manual
greater than full pipe that may extend up into the manhole during
surcharges conditions.
Water pressure impacts a diaphragm in the transducer that varies an
electrical current. This current is digitized by a sensor processor
board and the value is sent to the monitor processor board. A vent
tube on the back of the diaphragm equalizes for atmospheric
pressure. Three versions of pressure transducers are available with
this combo sensor: 0 - 0.34 Bar (0 - 5 PSI), 0 - 1.03 Bar (0 - 15
PSI), and 0 - 2.07 Bar (0 - 30 PSI).
Peak Velocity Sensor
To obtain peak velocity, this sensor sends an ultrasonic signal at an
angle up through the velocity layers in the oncoming flow. It emits
a wide, omni-directional sound wave at a specific frequency upward
into the flow. The sound wave bounces off particles in the flow and
returns to the sensor. The velocity sensor measures the change in
the sound wave's frequency from transmission to reception. This
change is used to determine the peak velocity of the flow based on
the Doppler effect.
Peak Combo Sensor peak velocity transducer
The Doppler effect describes the shift in frequency of a sound wave
emitted by a moving object in relation to a stationary point. The
moving objects represent particles in the flow, the stationary point is