(TFS-55 is now discontinued) -Part of Fluenta's entry range of ultrasonic transducers, the TFS-55 is specially designed and optimized to offer better performance in high attenuation, historically difficult to measure gas compositions such as those with high concentrations of CH4 and CO2.

Offering Better Performance with Difficult Gas Compositions

How is better accuracy achieved in high attenuation gases?

Just like the other transducers in the TFS range, the TFS-55 also features dual ultrasound measurement modes with one of them being the advanced “chirp” signal processing mode in which time varying signals are used, to ensure that the high measurement accuracy is maintained over a wide range of flow velocities.

The TFS-55 is part of Fluenta’s entry level range of ultrasonic transducers. It has particularly been designed  and optimized to accurately and reliably measure in high attenuation gas compositions. Such compositions have historically been difficult to measure due to them absorbing ultrasound signals and causing signal losses. This problem becomes worse with the increase in pipe sizes.

As the name suggests, the TFS-55 uses a 55KHz ultrasound signal. This is a lower frequency ultrasound signal than the others in the TFS family and as is demonstrated in the comparison on the right, a lower frequency signal is less affected by attenuation over the same distance.



The TFS-55 makes accurate measurement of gas compositions with high attenuation characteristics, such as those with higher concentrations of carbon dioxide and methane, possible. This has not been possible previously, especially across bigger pipe sizes.

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Onshore and Offshore Installations

Having an operating temperature range of -110 to +145°C makes the TFS-55 suitable for most flaring applications, both in onshore and offshore installations

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Features and Highlights

Boasting accuracies as high as ±2.5% combined with a repeatability better than 1%, the TFS range of transducers ensures that you have full visibility of gases going up your flare stack.

In addition to the Lateral-45 installation, which is the standard for Fluenta’s ultrasonic transducers, the TFS-55 is also available as Bias-90 installation. The Bias-90 installation is used in cases where either there are space restrictions or an existing bias-90 style installation is being replaced.

The TFS-55, in both Lateral-45 and Bias-90 installations, can be installed in either a single path or a dual path configuration. The dual path can be configured to either provide heightened security in terms of redundancy, when data continuity is of utmost importance or a more accurate measurement as with a dual path accuracy as high as ±0.75% can be achieved.

Key Specifications

Measurement Parameters

Standard and actual volume flow, mass flow, totalized standard volume flow, totalized mass flow, molecular weight, standard density, actual density, pressure, temperature, speed of sound, gas velocity


ATEX: Presafe 18ATEX13228X
IECEx: IECEx PRE 18.0062X
CSA: 70204508 – Class I Div 1
Inmetro: DNV 18.0183 X

Operating Temperature

-94 to +293 °F (-70 to +145 °C)

Operating Pressure

11.6 – 145 psiA (0.8 to 10 barA)

Flow Velocity Range

0.1 – 394 ft/s (0.03 – 120 m/s)


Standard: ± 2.5% to 5%
Optional: ± 0.75% to 2% (Dual-path configuration required for accuracy under 1%)


Better than 1% of volume flow for specific velocities

Turn Down Ratio


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