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High-temperature liquid flow meters from FLEXIM offer superior performance when it comes to providing accurate measurement for intensive industrial applications. Our high-temperature ultrasonic flow meters are capable of delivering non-invasive measurement even in severe conditions.

For example, toluylendiamine (TDA) is an important intermediate product for the production of polyurethanes. It is synthesized via Nitration of Toluol to Dinitrotoluol (DNT), which then becomes catalytically hydrated by Hydrogen under pressures of around 30bar and temperatures of about 150 °C. The hydration mixture is normally circulating out and into the reactors. As the circulation rate is crucial for the process control an accurate and reliable flow measurement is necessary.

At a TDA plant in Germany, Coriolis flow meters have been used at this measurement point before. However, these systems proved to be subject to wear from particles within the flowing medium and did not reach a satisfying service life. Moreover, the heating of the vibrating pipes within the Coriolis meter provides another difficult challenge.

The responsible plant engineers thus looked for a non-invasive measurement alternative - one that can also be employed at pipe wall temperatures of around 150 °C.

They found the ideal solution with the non-invasive ultrasonic flow meter from FLEXIM. The measurement point was equipped with ATEX Zone 2 certified high temperature transducers that can handle temperatures up to 200 °C. As the measurement system is installed at the pipe wall outside, it is not subject to wear and thus very reliable and durable. Also in terms of precision, the FLUXUS flow meter is up to the task.

Our high-temperature flow meters have performed under some of the toughest requirements in numerous industrial environments. If you would like to learn more about everything our solutions can do for you, reach out and speak with one of our representatives today.


  • Accurate, reliable and virtually maintenance free measurement solution - independent of high pressure and temperatures
  • No process shut downs for installation required
  • No potential of leaks of the toxic medium
  • No pipe constrictions, no pressure losses, no baffles within the pipe where particles could form deposits
  • No additional trace heatings required