Replacing Ultrasonic to Radar Level Transmitters

Real Story for Foam-Prone Process Tanks Improvement Project

In industrial environments, precise level measurement is critical for maintaining process efficiency and safety. However, challenging conditions, such as foam formation, can compromise the performance of certain level measurement technologies. This is a real story of how a facility replaced ultrasonic level transmitters with high-frequency radar technology from Endress+Hauser (E&H) to resolve issues caused by foaming in a process tank.

The Problem: Unreliable Level Readings in a Foaming Tank

1. Process Overview

• Industry: Chemical manufacturing.
• Tank Details: A 10-meter-high process tank used for mixing various chemical components.
• Existing Technology: An ultrasonic level transmitter was installed to monitor the liquid level.
• Challenge: During the mixing process, heavy foaming occurred on the liquid surface, causing the ultrasonic transmitter to deliver inconsistent and unreliable readings.

2. Symptoms Observed

• Fluctuating Level Readings: The ultrasonic transmitter frequently reported false low or high levels.
• Process Disruptions: Inconsistent level data led to incorrect control decisions, causing underfilling or overfilling.
• Safety Risks: Overfilling posed a risk of spills, while underfilling impacted product quality.

Troubleshooting the Issue

1. Initial Diagnostics

• Inspection of Transmitter:
  • The ultrasonic device was confirmed to be functioning correctly in a controlled environment.
  • However, it failed to maintain accuracy in the foaming tank due to the low-density foam reflecting the ultrasonic signal erratically.
• Process Observations:
  • The foam generated during mixing was dense enough to interfere with the ultrasonic waves but insufficient to consistently reflect the signal to the transmitter.

2. Root Cause Identification

• Foam Properties:
  • The foam had a low acoustic impedance, causing weak or scattered ultrasonic reflections.
  • Variations in foam density during operation exacerbated the problem, leading to fluctuating readings.
• Limitations of Ultrasonic Technology:
  • Ultrasonic transmitters rely on sound waves, which are highly susceptible to absorption and scattering by foam.
  • This technology proved unsuitable for tanks where foaming is prevalent.

The Solution: Transition to High-Frequency Radar Technology

After evaluating the situation, the team decided to replace the ultrasonic level transmitter with a high-frequency radar level transmitter. Endress+Hauser’s Micropilot FMR60 was chosen for its advanced capabilities.

1. Why Radar Technology?

• High-Frequency Performance:
  • The Micropilot FMR60 operates at a frequency of 80 GHz, providing a narrower beam angle and higher resolution.
  • High-frequency waves are less affected by foam, ensuring reliable level measurement.
• Non-Contact Measurement:
  • Radar technology uses electromagnetic waves, which are unaffected by foam density or variations in dielectric constant.
• Adaptive Signal Processing:
  • The FMR60 incorporates advanced algorithms to filter out interference from foam, focusing only on the liquid level beneath.

2. Installation Process

• Preparation:
  • The existing ultrasonic transmitter was removed, and the tank’s nozzle was inspected for compatibility with the radar device.
• Mounting:
  • The radar transmitter was installed on the same nozzle, with adjustments made to ensure optimal alignment.
  • A coaxial probe was unnecessary since the non-contact radar handled the foam effectively.
• Configuration:
  • The device was configured using E&H’s FieldCare software, setting parameters like:
    • Tank height.
    • Dielectric constant of the liquid.
    • Foam compensation settings.

Testing and Results

1. Commissioning

• Initial tests were conducted during active mixing to validate the radar’s performance under foaming conditions.
• The FMR60 consistently delivered stable and accurate readings, unaffected by foam thickness or density.

2. Improvements Observed

• Reliable Readings:
  • The radar transmitter provided consistent level data, even during peak foaming periods.
• Process Stability:
  • Accurate level measurements enabled better process control, improving product quality and reducing waste.
• Enhanced Safety:
  • Overfill risks were mitigated, ensuring compliance with safety regulations.

3. Operator Feedback

• The operators reported greater confidence in the system due to the radar transmitter’s stability and low maintenance requirements.

Benefits of the Transition

Lessons Learned

1. Know Your Process Conditions:
   • Technologies like ultrasonic transmitters are effective only in foam-free environments.
2. Evaluate Alternatives Based on Process Needs:
   • Radar technology, especially high-frequency models like the FMR60, is ideal for challenging applications involving foam, vapors, or high pressures.
3. Leverage Advanced Diagnostics:
   • Modern radar devices offer diagnostics and remote configuration, making them a long-term, cost-effective solution.
4. Consult Experts:
   • Partnering with manufacturers like Endress+Hauser ensures that the selected solution aligns with your specific process requirements.

Conclusion

Transitioning from ultrasonic to high-frequency radar technology resolved the level measurement challenges in this foaming process tank. The Endress+Hauser Micropilot FMR60 demonstrated superior performance by overcoming the limitations of sound waves and delivering reliable, accurate readings.

For industries facing similar issues, radar level transmitters offer a proven solution to ensure process stability, safety, and efficiency. Consider reaching out to E&H or other leading manufacturers to explore the best technology for your unique application.