Air spring elements stop vibrations during chocolate production

Success Story

Motek Hall 5, 5124 Stand

Belgian chocolate and pralines: these words alone give many gourmets a feeling of satisfaction and calm. These are now also given to the neighbor of a Belgian chocolate manufacturer. With the help of the ACE shock absorbers, it was possible to calm down the previously disturbing production at Libeert Premium chocolate by means of vibration isolation.

For over 90 years, the Belgian family business Libeert, based in Komen near the French border, has been creating premium chocolate products. The mixture of tradition and the latest production techniques leads to high-quality products, which are produced on the basis of 100% cocoa butter. The company from Hainaut, which has been awarded numerous quality prizes for the quality of its confectionery, is known internationally by young and old for fine chocolates and chocolates. Both product lines are offered in a wide variety of shapes and sizes, especially as it is a good tradition in Belgium, on different occasions such as Easter or Christmas, to have chocolate created in the form of many figures.

Secret thing Conching

The company faced a problem when shaping the chocolate: Part of the manufacturing process caused oscillations and vibrations that were transmitted to an adjacent residential building. The neighbor reported that furniture and dishes also started to vibrate. This intolerable situation was caused by a machine that was in operation 24 hours a day on weekdays. In order to understand the cause of these vibrations, one must become familiar with the manufacturing process of chocolate and with it one of its greatest mysteries.

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Clutches and brakes Use in food technology

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Press spokeswoman Désirée Libeert explains: “Behind the word conching lies the great secret of chocolate. The sweet, liquid mass is kept in constant motion over a longer period of time. This makes them creamy, and their flavors unfold in a special way. Finally, the liquid mass is poured into preheated molds, with special machines ensuring that the air bubbles that form are removed by vibration.”

In this case, however, the vibration units caused the neighborhood problems mentioned above. Because in order to get as many air molecules out of the chocolate as possible and so that they are distributed evenly in the mold, it also has to be shaken vigorously with Libeert. The vibration frequency depends on the viscosity and flow limit of the chocolate as well as on other parameters. Measurements by an independent and certified office had shown that the resulting interference frequency in this case was 16 Hz. This created another problem. Despite numerous tests, the Belgian confectionery specialists found no vibration solution that can isolate vibrations below 20 Hz. Jannick Dury, one of Libeert's technicians, came across an article about the PLM series from ACE shock absorber GmbH during his research. This is one of the "aceolators" launched on the market in 2013. After he asked if the new ACE products would help and if he could have more information on this, everything went very quickly.

Chocolate production stands on 14 soothing feet

PLM air suspension elements have been developed to provide low-frequency vibration and shock isolation at measuring stations or for fans, motor and generator units. Used as a kind of vibration damper, the internal air chambers offer a significant insulating effect from a frequency of 5 Hz and up. Ralf Küppers, Sales Manager at ACE shock absorber GmbH in the Benelux countries, answered Jannick Dury's first question with a clear “yes”. The further information he and Han Titulaer, technical adviser from ACE in Benelux, advised the chocolatier to fully utilize the maximum load on the individual air suspension elements. This is the only way to achieve the best insulation values. The PLM air suspension elements were selected based on the weight of the machine to be isolated. In the case described, it is a standard application, the system weighs 1800 kg and stands on 14 machine feet, for which a suitable insulation solution had to be found.

For this purpose, the model PLM3 with a maximum payload of 135 kg per air suspension element was chosen among the aceolators. An existing, smaller type would have been undersized. The PLM design has a vulcanized threaded insert that allows the air springs to be pressurized with either a standard tire valve or a pneumatic fitting. Special connections are not necessary. The natural frequency of these machine elements is in 3 Hz in the optimally loaded state. In the unpressurized state, it is 10 Hz, so that still noise from above 14 Hz can be isolated. A positive side effect of the PLM series: It levels the stored devices through its valve at the same time. If a compression fitting is attached to their products, they can be connected to the respective regulated air supply, which simplifies the process. In the event that no level control valves are used, a control unit can be provided to regulate the pressure and the height of the interconnected air springs.

The advantages highlighted were subsequently also put into practice. The PLM caused a reduction in vibrations around 80% in Belgium. The remaining vibrations can only be detected with measuring devices. This has brought peace to Komen - in the chocolate production and the neighbors.