Ultrasonic Clamp-on Flow Meter

Ultrasonic flowmeters utilize sound waves to measure fluid flow velocity. They operate on the principle of transit time, where ultrasonic waves are transmitted in both upstream and downstream directions. The difference in travel time between the two signals is directly related to the fluid’s flow velocity. 

• Transit Time Measurement:
  Ultrasonic flowmeters use two transducers that act as both transmitters and receivers of ultrasonic  signals.
• No Flow Condition:
  When there is no flow, the time it takes for the ultrasonic wave to travel from one transducer to the other is the same in both directions.
• Flowing Condition:
  When the fluid is flowing, the ultrasonic wave traveling downstream with the flow will travel faster than the wave traveling upstream against the flow. This difference in travel time is directly proportional to the fluid’s velocity.
• Calculation:
  By measuring these transit times (tAB and tBA), the flowmeter calculates the average fluid velocity (vm) using the formula: vm = k * (tBA – tAB), where k is a constant related to the meter’s design and the pipe’s dimensions.
• Volume Flow Rate:
  The calculated flow velocity, along with the cross-sectional area of the pipe, is then used to determine the volume flow rate.