There are main common reasons causing unstable readings or no signal for clamp-on ultrasonic flow meters:
1. Excessive air bubbles or suspended solids in the liquid
Too many bubbles, sediment or impurities will scatter and attenuate the ultrasonic wave, leading to signal loss and fluctuating flow values.
2. Heavy scaling, rust or thick lining on the pipe inner wall
Thick scale, rust layer, rubber or PTFE lining will block ultrasonic transmission, weaken the signal and cause poor measurement stability.
3. Unsuitable pipe material
Severely corroded cast iron pipes, thick fiberglass pipes and special composite pipes cannot transmit ultrasonic signals effectively.
4. Insufficient straight pipe section or poor installation position
Installing too close to elbows, pumps, valves or reducers causes turbulent flow, distorts the flow profile and affects signal stability.
5. Unfilled pipe (not full pipe)
The sensor requires a fully filled pipe. Half-full pipe will result in no valid signal and unstable data.
6. Improper sensor installation
Incorrect sensor distance, poor pipe surface polishing, or insufficient coupling gel will cause weak signal coupling.
7. High-viscosity or two-phase mixed liquid
High viscosity media such as heavy oil, lubricating oil, edible oil with impurities, and oil-water mixture will seriously affect ultrasonic propagation.
8. Strong on-site vibration or electromagnetic interference
Pipeline vibration and nearby high-power equipment interference will disturb the ultrasonic signal and cause unstable readings.
Post time: Apr-27-2026