Fixed Ultrasonic Flow Meter :: Transit time

Time of Flight :: Ultrasonic Flow Meters
 
 
The Dynasonics family of transit time ultrasonic flow meters are manufactured in the USA, to satisfy a variety of customer applications. The TFX range of products features clamp-on non-invasive meters designed to provide guaranteed accuracy and superb response characteristics for measuring clean liquids without affecting the exisiting pipework.
 
Operating Principle :: Time of Flight
 
Transit time flow meters utilize two transducers which function as both ultrasonic transmitters and receivers. The flow meters operate by alternately transmitting and receiving a frequency modulated burst of sound energy between the two transducers. The burst is first transmitted in the direction of fluid flow and then against fluid flow. Since sound energy in a moving liquid is carried faster when it travels in the direction of fluid flow (downstream) than it does when it travels against fluid flow (upstream), a differential in the times of flight will occur. The sound's time of flight is accurately measured in both directions and the difference in time of flight calculated. The liquid velocity (V) inside the pipe can be related to the difference in time of flight (dt) through the following equation: V = K * D * dt, where K is a constant and D is the distance between the transducers
 

Transit Time Operating Diagram