Ultrasonic Transit Time Flow Meters feature the most advanced non-invasive flow measurement technology available. These meters provide a low cost system with unsurpassed accuracy and versatility. Inherent advantages over competitive technologies include ease of installation, fluid compatibility, immunity to suspended solids and gas pockets, and a large, bi-directional measuring range.
The Transit Time Flow Meter utilizes two transducers which function as both ultrasonic transmitters and receivers. The flow meter operates 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.