AREA VELOCITY FLOW METERS - AVFM
Measure flow in part-filled pipes and open channels without weirs or flumes
Area velocity flow meters are the ideal solution for measuring flow in partially filled pipes and open channels. Ground water flowing in open channels or part filled pipes is normally metered using weirs, flumes or the Manning formula. Weirs and flumes frequently erode or silt up making metering misleading. The Manning formula model is strongly affected by changes in the channel conditions. Down-stream obstructions also lead to dramatic over-reading by all these metering methods.
Area velocity flow meters are the ideal solution for measuring flow in partially filled pipes and open channels. Greyline is a world leader in this application and there are many hundreds of Greyline Area Velocity Flow Meters measuring flow in Southern Africa. Greyline is a leader in all formats of water metering.
How It Works
- Level is measured by an ultrasonic sensor which can be mounted at the bottom of the channel, externally above the channel, or by a pressure sensor in the channel.
- Flow velocity is measured by a submerged Doppler sensor which is ideal for most surface water, waste water and effluent applications or alternatively by a non-contract laser sensor which is ideal for waste water and effluent.
- These measurements, combined with the stored data of the geometry of the channel give volumetric flow rate.
Water flow measurement
Area velocity flow meter
Area velocity flow meter 
Open Channel Flow Surveys-Stingray and Mantaray
While the AVFM is used for permanent installations, Greyline offer two portable solutions for site surveys using their proven Area Velocity Flow Metering technology. The Stingray and Mantaray are battery powered and are therefore ideal for spot checks or battery powered flow trend logging.
