Ultrasonic Clamp-on
Clamp-on ultrasonic flow meters operate on the principle of transit-time or
time-of-flight measurement. They work by sending ultrasonic signals through the
fluid in a pipe from one transducer to another, and then in the reverse direction.
The time it takes for the ultrasonic signals to travel downstream and upstream is
measured. When the fluid is flowing, the downstream signal takes less time to
traverse the pipe compared to the upstream signal. The difference in time is
proportional to the flow velocity of the fluid. By using multiple pairs of
transducers and carefully analyzing the time differences, these meters calculate the
average velocity of the fluid at different points within the pipe. This information
is then used to determine the volumetric flow rate of the fluid.
The "clamp-on" aspect refers to the non-intrusive installation of transducers on the
external surface of the pipe, making these flow meters suitable for retrofitting existing pipelines without disrupting the flow.