The Transit-Time Measurement Method
There is no need to cut pipes or halt production to measure fluid velocity. A Clamp-on Ultrasonic Flow Meter tracks flow non-invasively using acoustic signals sent directly through the pipe wall.
This relies on the transit-time difference method. Two external sensors pass sound pulses back and forth, where sound moving with the liquid flow arrives faster than sound fighting upstream against the current.
By measuring this tiny arrival gap, the processor delivers up to ±0.5% precision on our two-channel or four-channel setups, spanning pipe sizes from DN15 to DN6000.
Operators simply mount the external sensors to instantly get accurate, disruption-free flow data across any compatible pipeline.
Wave Refraction Through the Pipe Wall
Forcing acoustic signals to pass cleanly through a thick metal or plastic pipe wall presents quite a physical challenge. The angle of the mounting wedges is positioned with great care to make sure the sound doesn't simply bounce right off the hard boundary wall.
Instead, the sound waves change their physical behavior as they pass through the pipe wall, converting from a compressional wave into a shear wave. This physical phenomenon refracts the acoustic signal at a wider angle once it hits the liquid inside, creating a much longer path through the fluid. This extended path makes the entire Clamp-on Ultrasonic Flow Meter system highly sensitive to even minor changes in fluid velocity, capturing a clear reading instead of losing the signal in the metal.
Calculating Accurate Sensor Spacing
Achieving these highly reliable daily results requires mounting the sensors in the optimal physical position. Setting the exact distance between those two external units is the most critical step of the entire installation procedure. If they sit even slightly out of position, the receiving unit will miss the intended flow-sensitive wave entirely.
To find that absolute correct spacing, you simply provide the system with a few physical details through the large, easy-to-read LCD screen and its built-in keypad:
- How thick the pipe wall is.
- What specific material the pipe is made of.
- What type of liquid flows inside.
Previously, operators had to slide the sensors back and forth manually, a process that was time-consuming and prone to human error. Thankfully, our holder-type transducers perform the heavy mathematical calculations automatically to ensure the acoustic waves align perfectly for the given pipe geometry.
We offer an array of flexible converter styles, such as Wall Mount, Fixed Mount (made from die-cast aluminum), Panel Mount, DIN-rail Modules, and even a heavy-duty Explosion-proof converter rated for highly volatile DIIBT5 environments, making it incredibly easy to get a perfect fit on your specific pipeline layout.
Multi-Path Disturbance Compensation
While the basic concept of measuring a tiny time gap is straightforward, making it work reliably in a busy plant with swirling liquids has driven continuous engineering improvements. If your installation point sits directly after a sharp bend or a large valve where the fluid swirls heavily, standard single-path acoustic theory can sometimes struggle.
Utilizing our four-channel configurations solves this by allowing the Clamp-on Ultrasonic Flow Meter to read the flow from multiple intersecting angles simultaneously. This advanced multi-path method completely balances out the unstable fluid profile, compensating for the disturbed flow profile to deliver a clean, accurate reading every single time.
