Chocolatier demands a smooth production line

At the Zotter Schokoladen factory in Southeast Austria, the process of making chocolate from cocoa beans requires ingredients and mixtures in various states to remain in near-continuous motion for hours and days on end.

Smooth operation ensures top-quality final product. In addition, the production line is open to thousands of visitors every year, so the company is keen to avoid any malfunctions. Reliable drive systems are therefore vital, and the facility relies on geared motors from NORD Drivesystems for conveying, mixing and pumping tasks.

‘Black gold’: roasted and ground

The Zotter company introduces dozens of new flavours every year, ranging from pineapple, lemon and coconut, to celery, asparagus and cheese. But classic chocolate remains an indispensable ingredient for a large part of the product range. For years, chocolate has been produced in-house according to Zotter’s recipes.

Cocoa beans are cleaned, roasted for several minutes at temperatures above 100°C and subsequently sterilised under steam pressure. Conveyor drives with 0.75 kW rated power ensure transportation between the cleaning, roasting and sterilising stations. The next step is a crusher, where the cocoa nibs are de-shelled. A grinder with a NORD drive then turns the nibs into liquid cocoa paste, which is piped to a mixer. The pumps required for this stage feature 4 kW geared motors. Inside the mixer, sugar and sometimes dried milk are added to the cocoa paste. On top of that, extra cocoa butter is added from neighbouring tanks which are equipped with several 1.1 kW pump drives.

The raw mixture must be re-ground in a rolling machine.

Liquid turns solid ...

Mixing the cocoa mass with the other ingredients results in a pourable mass, which is ground in a rolling machine to achieve a fine texture. A dedicated worm gear unit powered by a 4 kW helical geared motor then ensures compression. This drive features an innovative construction which allows for using larger bearings in an overlapping offset configuration and shafts which are also larger than standard systems. The drive systems are therefore considerably stronger and more durable, since wear through radial and axial forces is minimised.

... and solid turns liquid

Conveyor drives then transport the solidified intermediate product through five rolling machines, where it is gradually refined. Only then does the mixture arrive at the last step of chocolate production. The single-shaft conche is used to reduce the water content, which ensures a smooth, silky consistency. Bitter compounds are evaporated through sophisticated temperature monitoring while the desired aromas remain. In this application, NORD drives are used for transportation, agitating and pumping tasks. A helical geared motor serves as a belt drive for filling the conche. Depending on the recipe, the chocolate mass is agitated for up to 48 hours at increased temperatures in a liquid state, until a product with the finest glaze and the desired aromatic profile is created. The agitator arms are moved by a space-saving direct drive. The parallel shaft geared motor used for this purpose provides a rated power of 55 kW. The conched mixture is evacuated via a pump system driven by a helical geared motor.

Thomas Linshalm, head of chocolate processing at the confectionery company, explains: “We operate a large number of geared motors. Just in case, it is therefore very important for us to always have quick access to spare parts. In general, however, the drives perform very reliably.”