Ultrasonic Flowmeter

A clamp-on ultrasonic flowmeter sends acoustic pulses diagonally through the pipe wall and fluid between two transducers. Pulses travelling with the flow arrive sooner than those travelling against it, and the transit-time difference gives the flow velocity. Nothing touches the process: there are no wetted parts, no pressure loss and no need to cut the pipe or stop production to install, verify or move the meter.

Transducers mount on pipes from ½" to 80" and the measurement is independent of process pressure. Transducer sets cover −196 to +480 °C, so cryogenic liquids and hot hydrocarbons are both within reach, and dedicated gas transducers handle natural gas, flare and process gas at sufficient pressure. Velocity range is 0.2 to 60 m/s. The meter measures pipe-wall thickness during setup and calculates mass flow from a built-in density model, with compensation for temperature.

Outputs are 4–20 mA HART and FOUNDATION Fieldbus. Multi-path versions improve accuracy on distorted profiles.

Clamp-on ultrasonic meters are the practical answer for toxic and corrosive services where a penetration is unwanted, for large-diameter water, cooling and crude lines where a flanged meter is prohibitively expensive, for check-metering and mass-balance surveys, and for temporary measurements during commissioning or troubleshooting. Users are oil and gas, water and wastewater, energy, petrochemical and chemical plants.