The DVA Pilot plant

Our Technical Centre is your link between idea, design and reality. In our laboratory machinery, future procedures can be tested, documented and proven. 

We can handle all liquid/solid substances.

The best selection of dryer

The influence of the wet product state on the choice of dryer construction

While with vacuum chamber dryers in closet or channel form, the state of the wet or dry product does not influence the basic drying process, for all the other following construction types, the state and characteristics of the wet product are crucial for the selection of the dryer. Even the behaviour of the product during drying and ultimately the state of the finished dried product play a particularly significant role in the ongoing work methods, especially the part remaining for final drying.

When an originally liquid wet product is still in a fluid or doughy state after complete dehumidification, this procedure, whether it is actually a drying process, can be treated entirely from the point of view of evaporation.

The following considerations are restricted primarily to cases in which the dry product is retained in an externally dry, i.e. more or less solid, form. 

  • One-drum dryers are predominantly used for the transformation of runny wet products into their corresponding dry state.
  • Meanwhile, two-drum dryers are more suitable for medium and thick liquids and also for doughy or pasty wet products. Particularly for the latter, the wet product must display sufficient adhesiveness to the hot rollers.
  • If runny wet products contain easily removable particles or super saturation and salt separation can be expected from gentle evaporation, the two-drum dryer would be favoured over the one-drum apparatus.
  • For thick, doughy and stiff, pasty wet product states, agitator/bucket dryers are preferred if the product disintegrates easily during advanced drying and usually does not display any baking properties that could lead to encrustation of the heating surfaces.
  • Bucket dryers are used for all wet products that have moist-crumbly, powdery or granular structures. 

Testable parameters

  • Feasibility
  • Scale-up for future production machinery
  • Ph values
  • Residual moisture
  • Process times
  • Granule size analysis
  • Drying procedure
  • Product alterations during drying processes (caramelisation; condensation)
  • Thermal behaviour
  • Determination of the most effective drying method

We would be pleased to support you with procedural designing, with experience as well as advice and participation.