Each STELA continuous-mixed-flow drier, mobile or stationary, consists of:  

  • column with drying and cooling zone
  • hot air generator
  • air technology
  • intake and exhaust air duct system

Basically, the whole drying plant is oversucked by the exhaust fan.
There are three different air duct systems (see diagram):

            
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1. Absolute suction system
The heated air is distributed in the hot air cap and constantly drawn through the drying elements. Fresh air is sucked through the cooling element via a separate cooling air duct; this guarantees an effective recooling of the product. The moistened air accumulates in the exhaust duct and is conveyed out of the drier by the exhaust fan.
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2. Suction system with heat recovery
The general mode of operation has already been described for the basic suction system. The extended suction system with heat recovery adds the hot exhaust air from the cooling zone to the hot air in the hot air cap and reuses it for drying. Thus the heat stored in the product is recovered.
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3. Suction system with heat recovery by circulating air duct system
This system increases specifically the recovered air and heat volume by using additional circulating air fans. This results in saving heating power of up to 20 %. All the exhaust air which is not completely saturated is led back into the hot air cap, i. e. not only the waste heat of the exhaust air of the cooling zone, but additionally of the lower drying elements is used. This circulating air is bundled by the circulating air fans and added constantly to the hot air in an especially constructed mixing zone. This system is especially suitable for a powerful and energy-optimized maize drying in one pass.