Revolution in drying technology: energy-efficient and fast

Our industrial world today would be unthinkable without the drying of solid materials – nevertheless drying is enormously cost-intensive and often has a harmful impact on the environment. Dr. Franz Groisboeck has developed a technical process for the drying of solid materials that changes these negatives to a positive. Important components of this invention are a largely sealed vessel, a drying gas stream and an efficient thermal circuit. The Salzburg-based firm Patentverwertungs GmbH is supporting Dr. Groisboeck in marketing his invention.


The new technical process is suitable for convective drying of solids. A stream of drying gas flows through material in a largely sealed vessel and transports the thermal energy needed. This stream consists mainly of water vapour and is circulated via a heat exchanger. A part of the main stream is diverted, condensed and then condensed out on the hot side of the exchanger. As a result, the amount of heat needed to evaporate the water during the drying process is returned to the main stream. This circuit of thermal energy ensures that only a small amount of external energy must be used to drive the compressor.

The advantages of this innovative process:

• Extreme efficiency in the energy input

• No smoke and no water vapour plume from the chimney

• Relatively low drying temperature – therefore limited evaporation of volatile substances and protection of the material being dried

• Relatively short drying time as the stream of drying gas mainly consists of vapour and this has much better thermal properties than air

• No fire hazard as the stream of drying gas consists mainly of water vapour

• Relative simplicity

• No loss or degradation of the valuable material dried (yield practically 100 %)


The energy-efficient process is not only kind on the environment, but at the same time is still gentle in handling the material to be dried.


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