Clamp-on flow meter: measuring without pipe intrusion
A clamp-on ultrasonic flow meter measures the flow of liquids and gases from the outside of the pipe. No cutting, no flanges, no process interruption. The sensors are simply clamped onto the existing pipe and the measurement can begin.
When is clamp-on the right choice?
Clamp-on measurement is in many situations not only more practical than inline measurement, but also the technically superior solution:
- For existing installations where modification would be costly or impractical.
- For aggressive, toxic or sterile media where contact with the fluid is undesirable.
- For temporary measurements or inspections where rapid deployment is essential.
- For pressurised pipelines that cannot be taken out of service.
- For measurement points where conventional inline meters offer no viable solution.
How does a clamp-on flow meter work?
The sensors are mounted on the outside of the pipe. They transmit ultrasonic signals through the pipe wall and into the medium. The instrument calculates flow velocity and volume flow from the transit time difference between the signals. There is no contact with the medium and no opening in the pipe is required.
Further information on the underlying measurement principle can be found on the Ultrasonic measurement techniques page.
Advantages of clamp-on measurement
No process interruption. Installation requires no downtime. Measurement starts while the process continues to run.
Suitable for short pipe runs and hard-to-reach locations. Where inline meters require a minimum straight pipe length, clamp-on sensors also perform on shorter sections. The compact, lightweight design of portable meters makes them easy to deploy in confined spaces and at height.
No wear or contamination. As no components come into contact with the fluid or gas, there is no exposure to aggressive or contaminated media and no risk of leakage.
Versatile and widely applicable. Pipe diameters from 3 mm to 6,500 mm, temperatures from -180 °C to +600 °C, flow velocities from 0.01 to 25 m/s. Compatible with virtually all pipe materials, clean and contaminated liquids, and gases.
Accurate. When correctly installed, a clamp-on ultrasonic flow meter achieves an accuracy of 0.5 to 1.5%.
Flexible. A portable clamp-on meter can easily be moved to the next measurement point. A fixed installation can be extended with pressure sensors, temperature sensors and wireless communication.
Applications clamp-on flow meters
Clamp-on ultrasonic flow meters are used for flow, level, pressure and wall thickness measurements in open and closed pipe systems, above and below ground. Applications range from drinking water and wastewater to petrochemicals, pharmaceutical production and cooling systems.
For a full overview, visit the Industrial applications page.
Measurements by U-F-M
U-F-M carries out clamp-on flow measurements on site, including full reporting. We survey multiple pipelines quickly and deliver measurement data that can be used directly for process optimisation, verification or compliance purposes.
Further information: On-site measurement service.
Like to know which clamp-on solution suits your situation?
View our clamp-on flow meters, or get in touch.