Unlike other technologies, ultrasonic measurement is not impacted by the composition or cleanliness of the gas flow. Ultrasonic transducers offer outstanding levels of repeatability and accuracy across a wide range of flow rates and temperatures. With no moving parts, the transducers require minimal maintenance. As Fluenta transducers are non-intrusive they are less prone to the build-up of dirt and corrosion that can affect measurement accuracy.

Ultrasonic flow gas measurement is the best technology for flare gas applications as it does not interfere or intrude into the gas flows and measurement accuracy does not rely on gas properties. Ultrasonic measurement allows measurement over a wide range of flows with turndown ratios of 4000:1

Fluenta Ultrasonic Transducers

Fluenta offers the most comprehensive range of ultrasonic transducers that cover the widest range of temperature applications, enabling accurate measurement of gas flow even in the most challenging industrial environments.

Our range
  • STANDARD TRANSDUCER: With a temperature range of -70 to +140°C, this transducer is suitable for most standard flaring applications in both on-shore and off-shore installations.
  • HIGH TEMPERATURE TRANSDUCER: The high-temperature range transducer is capable of functioning at up to +200°C, allowing Fluenta’s ultrasonic technology to be deployed across a wider range of flare applications, particularly valuable in chemical processing and refining.
  • HIGH METHANE AND HIGH CO2 CAPABILITY: High concentrations of methane and carbon dioxide have historically been challenging areas for ultrasonic gas sensors.

    Fluenta’s specialists have developed new transducers and signal processing algorithms designed specifically to work with these difficult gas types. This software, available for both the High Temperature and Cryogenic transducers, allows for automatic sensor frequency adjustments. The high methane and high CO2 software provides accurate flow measurements in gas concentrations up to 100%.

Easy installation

The Fluenta meter system consists of a pair of transducers which can be installed into the flare line using either a spool piece or hot or cold tapping methods.

The transducers are mounted in lateral flanges fitted with ball valves so that the transducers can be fitted or withdrawn whilst the flare line is in operation.

Compact installation

No conditioning plates or other pipework inserts are required, and all Fluenta transducers require just 10 pipe diameters of straight tubing before the transducers and 5 diameters downstream. The Fluenta field computer can be mounted up to 50 meters from the transducers, allowing for easy, compact and flexible installation and positioning. The transducers require minimal maintenance as they have no moving parts.

Accuracy and flexibility

Fluenta installations are available with a range of accuracies as low as ±1% , depending on customer requirements. See technical data for more details.

With a turndown ratio of 4000:1 and range of pipe diameters from 6 inch to 72 inch, the Fluenta ultrasonic flare gas solution covers a wide range of applications.

Non-intrusive measurement

Fluenta transducers are non-intrusive, meaning they are less prone to the build-up of dirt and corrosion which can impact the measurement accuracy, and do not affect gas flow.

Transducers which extend into the gas process are more likely to get damaged, increasing the need for repairs and replacement.

Broadband sensing

Fluenta’s transducers use broadband transmit and sensing, meaning they are not restricted to a single frequency. Using multiple frequencies is important in gas mixes which absorb ultrasound – primarily those with high concentrations of methane and CO2. Our specialist software can adjust frequencies to ranges where ultrasound signals are clearer.

Other systems use a single frequency for sensing, which is normally selected by the customer on order. This is a basic setup, not able to adjust to changing gas compositions.

Fluenta transducers use two ultrasound modes. “Continuous wave” uses a constant beam of ultrasound projected through the gas, whilst “chirp” uses short pulses. The ability to have both modes in a single sensor increases range and accuracy.

Other systems require a ‘dual path’ setup (needing four sensors) to achieve the same combination of range and accuracy.

Variable Wave Chirp Ultrasound
Continuous Wave Ultrasound
Full pipe diameter measurement

The Fluenta transducers measure flow across the whole diameter of the pipework. This gives the best sample of gas flow with a single pair of transducers. Other systems struggle with signal absorption in difficult gas mixes and therefore have very short distances between transducers – compromising the accuracy of the system.

Examples of intrusive sensors from other manufacturers

These two illustrations show sensors from other manufacturers which protrude into the pipework.

Whilst this has the advantage of making measurement easier for narrow band transducers, it comes with a number of disadvantages.

These sensors are vulnerable to damage from sand, water, oil and any other solid matter in the process. Given the high velocities associated with flare gas, impact damage can be severe and soon prevent the system from working.

These intrusive sensors also disrupt the flow of gas, causing turbulance in the region in which the sensors are measuring the flow. This turbulence can lead to inaccurate flow measurements.

Click here for current and historical Fluenta flare gas measurement product information, data sheets and more: