How to Select the Right Installation Point for Ultrasonic Flow Meter Sensors

Ultrasonic flow meters are widely used in various industries for their accuracy, non-intrusive design, and easy installation. However, choosing the correct installation point for the ultrasonic flow meter sensor is critical to ensure reliable and accurate flow measurements. This article outlines the key factors and best practices when selecting an installation location.
 

1. Choose a Fully Filled Pipe Location

The sensor should always be installed on a fully filled pipe. Ideal positions include horizontal pipe sections or vertical pipes with upward fluid flow. Avoid downward vertical flows with free discharge as this often leads to partially filled conditions, affecting measurement accuracy.
 

2. Select a Straight Pipe Run

To ensure a stable and fully developed flow profile, choose a straight pipe section where:

• The upstream straight length is ≥10 times the pipe diameter

• The downstream straight length is ≥5 times the pipe diameter
  This helps reduce turbulence and improve signal transmission. Also, avoid locations near valves, elbows, pumps, reducers, or bends.

3. Avoid High Points and Free Outlets

Do not install the sensor at the highest point of a pipeline or on a vertical pipe with downward flow, especially when there is a free outlet. These positions are prone to air accumulation or unsteady flow, which can lead to incorrect readings.

4. Use U-Shaped Sections for Open Channels

For open or partially full pipes, it’s best to install the ultrasonic flow meter at the lowest point of a U-shaped pipe section. This ensures that the pipe is fully filled and provides a stable measuring condition.

5. Consider Temperature and Pressure

Ensure that the selected installation point meets the operating temperature and pressure range of the ultrasonic sensor. Exceeding these limits can cause sensor malfunction or damage.

6. Check for Scaling or Sediment

Avoid installing the sensor on pipes with heavy scaling. If scaling is unavoidable, consider it as a fixed lining to calibrate the device accordingly. It’s best to install the meter on clean, scale-free pipe surfaces for optimal signal transmission.

7. Proper Sensor Alignment and Position

The two ultrasonic sensors should be installed on the horizontal axis of the pipe or within ±45° of the horizontal axis. This avoids interference from air bubbles at the top or sediment at the bottom of the pipe, which could disrupt ultrasonic signals.

If space is limited, angled or vertical sensor installation is acceptable, as long as the upper section of the pipe is bubble-free.
 

Conclusion

Choosing the right installation point for ultrasonic flow meter sensors is essential for achieving accurate and stable flow measurements. Prioritize full pipe flow, adequate straight pipe lengths, and avoid disturbance sources such as valves and pumps. Proper positioning and alignment will help reduce signal interference and ensure long-term performance.