ADS Environmental Services ADS TRITON+ QR 775027 A3 - Manual (Page 58)

System Overview 2-21
Surface Velocity Sensor
This sensor measures the velocity of the flow also by bouncing
signals off the flow surface using a method similar to the ultrasonic
depth sensor, but the velocity signals are angled toward the
oncoming flow surface.
The surface velocity sensor crystals reside in the two descended
portions toward the rear end of the sensor.
ADS does not recommend using this sensor for measuring velocity
at locations with smooth flow surfaces or velocities of less than 1
foot per second (0.3 m/s).
FLOW
SURFACE VELOCITY
Measuring velocity using the surface velocity sensor
Surcharge Peak Velocity Sensor
This sensor measures the velocity of the flow during surcharge
conditions using the same methodology as the Peak Combo
Velocity Sensor. Therefore, it will measure velocity only when the
pipe is full.
The surcharge peak velocity sensor resides in the angled, front
portion of the sensor in front of the ultrasonic depth crystals.