Radar measurement for fruit juice production

A practical solution for continuous level monitoring of several storage tanks was implemented near Cape Town for fruit juice production. It had to be considered that there are agitators inside the containers and that the material to be measured is sticky and viscous. Food-compliant, certified UWT radar technology was finally the right ingredient for precise content detection.

Fast & precise detection of moving surfaces

Reliable overfill protection, quick reaction when emptying the silo / tank, transparency and control of the fill level within the process container at all times, all of this enables functional content monitoring. In order to define a suitable level measurement technology, it is essential to analyze the various process parameters of the individual application, material properties, temperatures, pressure and connections as well as the process atmosphere.

 

A leading manufacturer of various fruit juice products was looking for a reliable solution for continuous level measurement within his storage tanks near Cape Town. In addition to fruit juices and fruit concentrates, emulsions, pastes and purees are produced there for the South African market. In a gentle, modern juice production process, the fruit is cold-pressed, mixed and preserved, which among other things means that the juices remain fresh without the use of heat. A solution was needed to determine the fill level within the storage processes in real time. The challenge here was to ignore the agitators in the tanks, which constantly stir the juice, at the same time. The question was which technologies work best under these process conditions and realize a precise measurement of the moving surface. In the food industry, absolute hygiene is crucial and high demands are placed on the measurement technology to be installed in terms of design, functionality and reliability. There are temperatures of up to 80°C (176°F) and a process pressure of about up to 0.8 bar (11.6 psi) in the processes of the fruit juice producer. The respective DK value of the different juice products is at least 4.0 with a water / oil based material characteristic. There is no vibration within the application.

After a test phase with local partner Morton Controls CC on site, the customer was very satisfied with the results of the contact-free radar sensor, which is popular in the food industry, and its accuracy. Electromagnetic waves form the basis of level measurement with radar. A radar sensor emits a bundled electromagnetic wave that is reflected by objects as an echo and evaluated by the sensor. In addition to free-radiating radar sensors, the radar category also includes those based on guided microwave technology, which are referred to as guided wave radar, TDR (Time Domain Reflectometry). Free-radiating radar sensors are generally characterized by their frequency, as this is important for the non-contact level determination in process or storage containers. Radar sensors with high frequencies can be made more compact, have smaller radiation angles and better reflection properties, which finally leads to precise and reliable measurement results. This is why the free-radiating UWT radar sensors also work with 80 GHz technology.

Free-radiating radar with very small beam angle

35 radar sensors of the NivoRadar®  NR 3000 series with adjustable aiming flange were installed. In this way, the probe of hygienic design could be fixed at a desired point and the angle of the beam adjusted accordingly. Thanks to the perfect alignment of the radar, the agitators did not influence the measurement results in any way. The 4° narrow beam and a measuring range of up to 100 meters made the sensor a compatible solution for the single-chamber tanks. The radar also has a standard cleaning function for the lens antenna with high resistance to material adhesion. This offers a rinsing connection (air) for the self-cleaning of very sticky materials. The user-friendly display, the quick commissioning wizard and the diagnostic data shown made it easy to install on site. The configuration was done with only 6 parameters.

For the juice producer in South Africa, the continuous level measurement of the storage tanks became an elementary part of its efficient plant processes. With the application-oriented product design of the installed radar sensors, there was a high degree of compatibility in accordance with the process conditions, so that they can be seamlessly integrated into the system and ensure optimal storage management.


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