Area-Velocity Flow - How it Works

Area-Velocity Flow Measurement

An Area-Velocity Flow Meter continuously measures both Level and Velocity to calculate flow volume in an open channel or pipe.

View Flash Animation of Greyline Area-Velocity Flow Sensor

The ultrasonic sensor is installed at the bottom of a pipe or channel. To measure water level the sensor transmits ultrasonic pulses that travel through the water and reflect off the liquid surface. The instrument precisely measures the time it takes for echoes to return to the sensor. Based on the speed of sound in water, the level is measured with accuracy of ±0.25%.
Flow velocity is measured with an ultrasonic Doppler signal continuously injected into the water. This high frequency sound (640 KHz) is reflected back to the sensor from particles or bubbles suspended in the liquid. If the fluid is in motion, the echoes return at an altered frequency proportionate to flow velocity. With this technique the instrument measures flow velocity with accuracy of ±2%.

Greyline Area-Velocity Flow Meters work in partially full and surcharged pipes, rectangular, trapezoid and egg-shaped channels.

A separate down-looking ultrasonic sensor can be used for highly aerated or turbulent flow applications. It measures level by transmitting ultrasonic pulses through the air to the liquid surface with accuracy of ±0.25%. Along with the level sensor, a submerged Doppler velocity sensor is used to measure the water velocity.

Copyright © 2004-2006 [Greyline Instruments Inc.] All rights reserved.

Return to Greyline AVFM-II Area-Velocity Flow Meter.
Return to Greyline Stingray Portable Level-Velocity Logger.
Return to Greyline Products for more Flow and Level model information and specifications.

Area-Velocity Flow Measurement
An Area-Velocity Flow Meter continuously measures both Level and Velocity to calculate flow volume in an open channel or pipe.
View Flash Animation of Greyline Area-Velocity Flow Sensor
The ultrasonic sensor is installed at the bottom of a pipe or channel. To measure water level the sensor transmits ultrasonic pulses that travel through the water and reflect off the liquid surface. The instrument precisely measures the time it takes for echoes to return to the sensor. Based on the speed of sound in water, the level is measured with accuracy of ±0.25%. Flow velocity is measured with an ultrasonic Doppler signal continuously injected into the water. This high frequency sound (640 KHz) is reflected back to the sensor from particles or bubbles suspended in the liquid. If the fluid is in motion, the echoes return at an altered frequency proportionate to flow velocity. With this technique the instrument measures flow velocity with accuracy of ±2%. Greyline Area-Velocity Flow Meters work in partially full and surcharged pipes, rectangular, trapezoid and egg-shaped channels.
A separate down-looking ultrasonic sensor can be used for highly aerated or turbulent flow applications. It measures level by transmitting ultrasonic pulses through the air to the liquid surface with accuracy of ±0.25%. Along with the level sensor, a submerged Doppler velocity sensor is used to measure the water velocity.
Copyright © 2004-2006 [Greyline Instruments Inc.] All rights reserved. Return to Greyline AVFM-II Area-Velocity Flow Meter. Return to Greyline Stingray Portable Level-Velocity Logger. Return to Greyline Products for more Flow and Level model information and specifications.