Jürgen Skowaisa on setting new standards in radar level measurement
In May 2016 Vega Grieshaber KG launched the Vegapuls 64. It is the firm’s first radar level sensor for liquids that measures at the high frequency of 80GHz. This feature allows for a considerably better focusing of the radar beam.
Measuring is now much easier and more reliable, even under difficult conditions, such as tanks fitted with heating coils, baffles or agitators.
Until now, a radar sensor with a transmission frequency of 26GHz and an 80mm diameter antenna used to have a beam angle of approximately 10°.
With the same size of antenna, the Vegapuls 64 has a beam angle of only 3°. The larger the dynamic range of a radar sensor, the higher the measurement certainty and the wider the range of applications that the sensor can be used for.
Media with very poor reflective properties, i.e. a low dielectric constant, can now be measured with more certainty than previous radar level sensors. Even foam, turbulent product surfaces, condensation or build up on the antenna are no problem. The product has a measurement accuracy of +/-2mm, even with a measuring range of 30m.
Trends in processing industries
The current trend in the chemical industry is towards smaller, specialised batches. This results in equipment and containers with reduced volume.
The antenna system of the new solution is integrated directly into the process fitting. Since no antenna protrudes into the vessel, it is possible to measure up to the process fitting itself. This gives greater flexibility because practically all of the container volume can be utilised. The big advantage of radar technology is its immunity to process conditions such as temperature, pressure and density.
Especially great is the need for safety in the petroleum processing industry, for example in storing liquid gas in spherical tanks. Thanks to Vegapuls 64’s powerful signal focusing of 80GHz, there are now more possibilities for mounting sensors on shut-off valves than ever before. Another advantage for the user is that the new sensor can be installed on existing shut-off devices. This keeps modification and retrofitting costs to a minimum.
With its small antenna system, the sensor is ideal for use in vessels with small process connections, such as those used in the pharmaceutical, biotech and food industry. It is also particularly suitable for use in these industries due to its hygienic materials and design. The relevant approvals for this sector, such as 3A, FDA and EHEDG, are available.
The 80GHz frequency considerably reduces interfering signals generated at close range, both right up to the process fitting and down to the very bottom of the container. Since existing process connections can be used, the new sensor can be easily installed without costly equipment modifications. The radar signals pass right through viewing windows and glass containers so that the sensor can also be mounted outside the container.
In the shipbuilding sector, where every millimetre counts, the Vegapuls 64 shows off its assets. It can detect down to the very last millimetre at the bottom of storage tanks on ships, which is significant because on lager tankers, 1mm of filling height usually corresponds to thousands of litres of crude oil or fuel.
Thanks to the tightly focused measuring beam, only a very small liquid surface area at the tank bottom is needed to determine the exact level. The encapsulated antenna system ensures that the sensor works reliably and maintenance free, even in rough seas. It can even be used in vessels with internal installations or heavy build up on the walls, as its focused microwave beam simply avoids these obstacles.
Opening up areas of new application
The diameter of the smallest version of the Vegapuls 64 is no larger than a 1 Euro coin. As can be seen in the above examples, besides its applications in mainstream manufacturing and processing industries, the sensor opens up application possibilities in pilot plants and even laboratories, which, for space reasons, had to do without radar level measurement technology until now.
For more information, visit www.engineerlive.com/process
Jürgen Skowaisa is with Vega.