Getrocknete Kräuter
Success story: herb drying

Velvet gloves for herbal treatment

Dried herbs have not only become an indispensable part of the kitchen. For millennia, they have also played an important role in the preparation of medications. One commonly encountered form is chamomile tea. The drying process is time-consuming. The herbs must be treated gently to guarantee optimal quality and the highest possible content of the active substance.


At Hofgutkräuter GmbH & Co. KG in Reinheim, Germany various herbs are dried using a belt drying machine for further processing at tea producers or extractors. Among these are chamomile, peppermint, dandelion, arnica root, lemon balm, artichokes, and parsnips.

Depending on the product, the temperature and belt speed of the drying process vary. The products to be dried are brought to the belt dryer with a conveyor belt. As the herbs pass through the system with a total of 5 turning points, they are dried by a supply of warm air.

Herb drying

Solution approach

The belt dryer used up to now by Hofgutkräuter GmbH & Co. KG in Reinheim, Germany has been retrofitted to improve the energy efficiency and increase the flexibility of the system.

At about 20 measuring points on and in the belt dryer, temperatures, pressures, fan and exhaust air speeds, and belt drives are measured as well as controlled for each drying process using the JUMO mTRON T automation system. The system is monitored for malfunctions and the measured values are saved to ensure traceability and documentation.

Humidity and temperature controllers are used in the supply air area. Hygrothermal transducers and temperature probes are also used. In the exhaust air section, JUMO dTRON controllers are deployed (among other devices) as speed sensors along with JUMO differential pressure transmitters. Also, the belt drive is controlled by JUMO dTRON controllers.

Inside view of the belt dryer

Inside view of the belt dryer

Feeding the supply

Feeding the supply

Project outcome

The extensive portfolio allowed JUMO to modernize the entire plant. 14 multichannel controller modules, 16 analog input modules, and 19 digital input or output modules are used in addition to 2 central processing units. The complete sensor technology system was also supplied.