A handheld ultrasonic flow meter offers convenient, non-invasive flow measurement, but accurate results depend on more than the instrument itself.
The Lanry TF1100-CH uses transit-time ultrasonic technology. Its measurement performance depends on pipe conditions, liquid properties, sensor installation, and flow stability.
Understanding these factors helps engineers obtain more reliable readings in the field.
Pipe Material and Wall Thickness
Ultrasonic signals must pass through the pipe wall before traveling through the liquid.
Different materials transmit ultrasonic energy differently. Thick walls, corrosion, heavy scale, and certain internal liners can weaken or distort the signal.
Before measurement, enter the correct pipe material, outside diameter, and wall thickness. If the pipe has an internal liner, provide that information as well.
Liquid Conditions
Transit-time ultrasonic flow meters are generally suitable for clean liquids that transmit ultrasonic signals adequately.
Excessive air bubbles or suspended solids can scatter or attenuate the signal. The effect depends on their concentration, size, and distribution.
For wastewater or process liquids, confirm the application with the manufacturer before selecting a clamp-on meter.
Sensor Spacing and Coupling
Incorrect sensor spacing is a common cause of unstable readings.
Use the spacing calculated by the meter for the selected sensor configuration. Apply suitable coupling gel between the transducers and the pipe surface to improve acoustic contact.
Ensure that the sensors are securely mounted and correctly aligned.
Installation Location
Elbows, pumps, valves, and reducers can create non-uniform flow profiles that affect velocity measurement.
Where possible, install the sensors on a straight pipe section: 10D upstream and 5D downstream.
Always follow the manufacturer’s installation recommendations for the specific application.
Low Flow Velocity
At low flow velocities, the transit-time difference can become very small, making the measurement more sensitive.
If readings fluctuate, check the sensor installation, pipe parameters, and actual process conditions before assuming the meter is defective.
Pipe Filling and Flow Stability
The pipe should be completely full at the measurement point.
Air pockets near the top of a pipe or partially filled sections can make the measurement unreliable.
Choose a location where the pipe remains full during normal operation.
✓ How Can You Improve Measurement Reliability?
Before recording the flow rate:
- 01 Verify all pipe and liquid parameters.
- 02 Clean the sensor contact area.
- 03 Apply coupling gel and mount the transducers correctly.
- 04 Confirm signal quality.
- 05 Select a suitable measurement location.
- 06 Wait for the reading to stabilize.
- 07 Repeat the measurement if necessary.
These steps help reduce installation errors and improve the repeatability of field measurements.
Frequently Asked Questions
Does a stronger ultrasonic signal always mean better accuracy?
Not necessarily. A good signal is important, but correct pipe parameters, sensor positioning, and stable flow are also essential.
Can pipe wall thickness affect measurement?
Yes. Wall thickness and material affect ultrasonic transmission and must be considered during setup.
Why does the flow reading fluctuate?
Possible causes include unstable flow, weak acoustic coupling, incorrect sensor spacing, unsuitable pipe conditions, or incorrect configuration.
Post time: Oct-19-2026