Open Channel – Area Velocity
Open Channel Area Velocity measures flow in part-filled pipes and open channels without weirs or flumes
Weirs and flumes frequently erode or silt up, making flow readings misleading. And the flow formula is strongly affected by changes in channel conditions.
Down-stream obstructions can lead to dramatic over-reading. So Open Channel Area Velocity Flow Meters are the ideal solution for measuring flow in partially filled pipes and open channels!
How it works ‒ Open Channel Area Velocity Flow meters
- Level is measured by an ultrasonic sensor which can be mounted at the bottom of the channel or externally
above the channel. - Flow velocity is measured by a submerged Doppler sensor.
- These measurements, combined with the stored data of the geometry of the channel, give volumetric
Greyline Area Velocity Flow Meters
There are hundreds of Greyline Open Channel Area Velocity Flow Meters operating in South Africa measuring storm water run-off, waste water, effluent and irrigation water. The Doppler Flow Sensor measures flow rate up to 6.2m/s. The built-in ultrasonic level sensor delivers a head measurement from 26mm to 4,570mm. An external non-contact ultrasonic level sensor is also available. The AVFM has three 4-20mA outputs for flow, level and velocity, optional on board data logger and Modbus output.
Open Channel Flow Surveys
Greyline’s Stingray and MantaRay battery powered Area Velocity Flow Meters are used for site surveys. These meters measure velocity and level in the channel and calculate flow.
This information is available on the display, via 4-20mA output and on-board data logger. Using a 15 minute sample interval, the MantaRay’s on-board batteries will deliver a logging period of 2 months.
The MantaRay is a portable area velocity meter that measures flow using a submersible ultrasonic sensor. The unit is designed for flow surveys in open channels, partially-full sewer pipes, and surcharged pipes – making the portable open channel flow meter suitable for sewer monitoring, industrial flow monitoring, irrigation flow, and natural streams.
