Levels reliably in view 

To prevent flooding of a chromium collection tank, a Belgian service provider therefore relies on the new compact radar level sensor VEGAPULS 21.

Belgium's ENGIE Solutions specializes in water treatment. For a large engineering company around Liege, Engie handles the treatment of wastewater and other fluids from various processes. A particular challenge was the wastewater from an installation that treats the surfaces of metal parts. The chromium contained in it first had to be extracted and then purified. Chromium is dangerous because of its possible effects on health and the environment. Therefore, the collected chromic acid solution is stored in a double-walled HDPE tank to avoid leakage. The tank must be utilized as optimally as possible, but under no circumstances should it be overfilled. For level monitoring, ultrasonic technology is classically chosen in water treatment. VEGA field manager Vincent Vanwelde: "Until recently, it was not easy to demonstrate the added value of a radar level sensor since price is a very important criterion in water treatment. With the launch of our new VEGAPULS series, our radars are now offered at the same price but with much greater reliability and ease of use."

Simple solution protects employees

"I was looking for a level measurement solution that posed no risk to my employees," says Laurent Roumieux, team leader at Engie. "Recently, with the help of Vincent, my contact at VEGA, I installed a non-contact radar measurement on an HDPE tank filled with hydrochloric acid (HCl). This was a simple and above all safe solution because it measures through the wall. Since its commissioning, this sensor has provided reliable readings." Because of this positive experience, Roumieux wondered if this sensor could also be considered for measurement on the tank with the aggressive chromic acid solution. "If we can standardize all our installations on the same model, we only need to stock one type of probe suitable for all measurements. Then our technicians would also no longer have to work with different brands and installation programs." The application was considerably more complex, however, as it involved a horizontal, cylindrical tank with a double jacket. 

Good signal focusing leads to more accurate readings

The heart of VEGAPULS 21 is a radar microchip newly developed by VEGA, specially optimized for the requirements of level measurement and very compact. Thanks to the 80 GHz technology, the radar beam can be focused almost to the millimeter on the medium to be measured. As a result, measurement and interference signals are better separated - measurement becomes much easier, more accurate and no interference signal suppression is required. Not only do radar sensors operate independently of temperature fluctuations, vacuum and high pressure, they are particularly insensitive to contaminants. These properties make the VEGAPULS 21 predestined for this application, so to speak. "For the installation, I did not have to drill through both walls of the tank, as the sensor measures through the roof of the tank! This makes the measurement safe, because my staff never comes into contact with the chromic acid solution when using the sensor," Roumieux says. "Moreover, we were able to avoid damage and costs." Another advantage is that the new compact sensors measure without block distance to the edge of the tank. Thus, the volume of the tank can be fully utilized.

A look inside the tank with the app

For the ENGIE team, the new sensor not only led to greater safety in use, but also to faster installation. Via the VEGA Tools app, the radar sensor could easily be optimally aligned on the cylindrical tank. An application that mechanic Yannick Crouquet found extremely practical. "This means I no longer have to use a level or scaffold on the tank to align the sensor," he said. The app allows wireless control of sensors that have a Blue-tooth function. All relevant information about the VEGA instrument can be retrieved. This makes subsequent maintenance tasks easier. A perfect solution for a sensor on a chromic acid tank, as mounting and working on the cylindrical HDPE tank should be avoided. Crouquet explains, "Thanks to the VEGA Tools app, I was able to remotely monitor the measurement results and signal quality of the measurement probe in the first few days. After a few days of observation, I knew that the VEGAPULS 21 was working. Accessing the parameters afterwards and the program of my new level sensors is also much easier. It's a real time saver and less restrictive."