Clamp-on – Measure flow without cutting the pipe
Clamp-on – Measure flow without cutting the pipe
Do you want to measure the flow in an existing pipe without any pipe work or downtime? With a clamp-on flow meter (ultrasonic flow meter), the sensors are mounted directly on the outside of the pipe. You can monitor the flow without cutting into the pipe or modifying the system.
This technology is suitable for both continuous monitoring and periodic inspections in the industrial, real estate, energy, and HVAC sectors.
How the Measurement Works
Two transducers transmit ultrasound through the pipe wall and the fluid, alternately with and against the flow. The sound travels slightly faster with the fluid's motion than against it. The meter compares the difference and calculates the flow rate.
In a typical installation, both transducers are mounted on the same side of the pipe. The ultrasonic signal travels through the fluid, bounces off the opposite inner wall of the pipe, and continues to the other transducer. The path of the ultrasonic signal then forms a V. This is called the V-method.
Depending on the pipe diameter, the transducers can also be mounted on opposite sides of the pipe. The ultrasonic signal then travels directly through the liquid to the other transducer, without bouncing off the inner wall. This is called the Z-method.
Everything happens automatically. You can read the flow rate on the display or forward the measurement values to your system.
For example, the LRF-3000S takes over 300 measurements per second, providing a dense data set for calculating the flow rate.
The sensors are mounted on the outside—operations continue
Since the sensors do not come into contact with the liquid, there is no need for drilling or cutting.
This offers several practical benefits:
- Installation without draining the pipe or interrupting operation.
- No pressure drop from the meter.
- No moving measuring parts in the fluid.
- Ability to add metering to existing facilities.
- The ability to move a portable meter between different measurement points.
Which pipes does it work on?
Clamp-on works on most homogeneous pipes where the ultrasonic waves can pass through the pipe wall. Common examples include steel, stainless steel, copper, and plastic pipes such as PE and PVC.
This means you often won't need to replace any part of the piping. We'll help you choose the right sensor for your pipe.
The tube must be completely filled with liquid at the measurement point. This allows the sound signal to travel through the liquid and provide a reliable measurement.
For cold and hot liquids
With the right model and sensor, solutions are available for medium temperatures ranging from −40 to +180 °C.
This makes the clamp-on sensor useful for everything from cold water and cooling systems to heating and hot process fluids. The temperature range depends on which sensors and meter you choose.
What kinds of liquids are suitable?
This technology works well with water and many other liquids that allow ultrasound to pass through them.
Too many particles or too much air in the liquid can interfere with the audio signal. Liquids with a high particle content, such as paper pulp, are therefore not suitable for this type of clamp-on measurement.
At a wastewater treatment plant, for example, the technology may be suitable for treated water and other appropriate water flows. Sludge and heavily aerated liquids must be evaluated separately.
Not sure if ultrasound is right for your liquid? We'll help you figure it out.
Here's where you can use a clamp-on
Industry and Processes
Check cooling water, process water, and other fluid flows. Monitor changes in operations or verify that pumps and valves are providing the required flow.
Real Estate, Heating, and Cooling
Measure flow in heating and cooling circuits, at heat exchangers, or in different parts of a building portfolio. With temperature sensors and an energy function, you can also monitor power and energy.
Wastewater Treatment Plants and Water Treatment Facilities
Monitor appropriate water flows in pumping stations, water treatment, and purification processes without having to rebuild the pipeline.
Boats and Marine Facilities
For example, monitor cooling water and process water circuits. Surface-mounted sensors make it possible to add monitoring capabilities to existing systems where space may be limited.
Sprinkler System
Use a portable meter for flow control and periodic testing, or choose a permanent installation for periodic readings. Measurements are taken without the need to install a meter inside the pipe.
Hospitals and large facilities
Monitor flows in technical water, heating, and cooling systems where operational interruptions are difficult to plan for. Start with selected measurement points and expand as the need grows.
A fixed measurement system or a portable monitor?
A stationary meter is suitable when you want to monitor the same measurement point over time and collect measurement values on an ongoing basis.
A portable meter is ideal when you want to troubleshoot, perform temporary checks, or use the same instrument in multiple locations.
See our ultrasonic flow meters
Would you like to measure energy as well?
With flow measurement and temperature sensors on the supply and return lines, a meter with an energy measurement function can calculate the transmitted power and energy.
This provides a better basis for monitoring heating and cooling, comparing systems, and detecting anomalies.
We'll help you get started
You don't need to understand the technology yourself or know which model to choose. Just tell us what you want to measure, and we'll help you find the right solution.
We also help you find the right flow meters for your entire project—from the initial measurement points to larger and recurring deliveries. You’ll receive personalized advice, a comprehensive quote, and support in selecting the right products. It’s easy to get started and easy to order more as your needs grow.
Fredrik Hylta – Assistance with Product Selection and Projects