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!

The Area Velocity Flow Measurement method is the most common method of all flow measurements. Pulsar AVFM 6.1 Area Velocity Flow Meter using a submersible ultrasonic sensor, measuring both the level and velocity of flowing liquid to calculate flow measurement in an open channel or pipe. The sensors are mounted either inside a pipe or at the bottom of a channel The sensor is built to resist fouling, corrosion, and abrasion. The AVFM 6.1 Area Velocity Flow Meter can be configured with the standard submerged velocity-level sensor, or with submerged velocity in combination with a separate non-contacting ultrasonic level sensor. This is suitable for highly aerated fluids or those with a high concentration of suspended solids.

open channel area velocity

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.

 

Flow velocity up to 6m/s

Pulsar AVFM 6.1 can measure forward flow velocity up to 6 m/s and reverse flow up to 1.5 m/s. The electronics and software sample and average flow rates continuously provide stable readings. The submerged velocity/level sensor will measure flow in partially full and surcharged pipes with pressure up to 10 psi. The minimum recommended pipe diameter for the AVFM 6.1 Area-Velocity Flow Meter is 150 mm.

Open Channel Area Velocity

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.

open channel area velocity
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