Belt Dryers

Belt Dryer

Belt dryer AGRO is designed for processing of biomass, agro material, agricultural commodities, cereals, hops, hemp and suchlike material.

This dryer works on the principle that hot air is led into the enclosed drying box which is divided into three drying zones.

Process of drying and regulation

The drying process of agricultural materials such as hops, hemp, cereals and other commodities of vegetable origin is dependent on input moisture, size and fraction of material, required output moisture and acceptable admissible input temperature.

The system is controlled by central electric switchboard which is equipped by PLC control unit that works with transferred data from sensors and thermocouples. In connection to these data adjusts the automatic run of the whole system in the way to reach the required parameters during the drying process. The process of drying and thus the quantity of finished dried material can be regulated in two following ways.


Material input, feed and output

Input and output of material are ensured by belt conveyor and enclosed rotary dispenser. Finished dried material is discharged also by belt conveyor. Inside the box, material is advanced on three Teflon belts and constantly dried to the required output moisture with the help of hot air inlet throughout the whole process of drying. Output moisture of used material can be regulated by means of input temperature value 68–300 °F (20–150 °C) as well as by various speed setting of drying belts.

Blowing heated air

Heated air is led into the drying box by two transport fans by means of distributive pipeline into the individual zones, then through diffusor nozzles, onto the material that is drying along the entire length of the drying belts.

Air flow regulation

Air flow in the zones is regulated by closing plates by which it is possible to regulate differential pressure in individual zones. Air pressure which is led on the material can be also regulated by these closing plates.

Humid air extraction

Moist air and fine particles are sucked out of the system by discharge fan through solid particles separator when the air is led out of the system and fine particles are
separated from the air by means of rotary valve. Both types of fans i.e. transport and discharge fan, are regulated by frequency converters by which airflow volume in the drying box can be set.


The motion of belts is monitored by sensors and in the case of belt deviation out of the roller, the belt is then automatically leveled by actuator for belt alignment. In order to ensure heat for the whole drying system it is possible to use gas, diesel or oil aggregate with the power of 1,700,000–2,050,000 btu/h (500–600 kW).

Technical Parameters

Voltage 480 V/60 Hz (400 V/50 Hz)
Installed electric power 77 Amps (64 kW)
Rated heat output 1,700,000 BTU/h (500–600 kW)
Fuel light heating oil, natural gas, LNG
Fuel consumption (light heating oil) 10.04 gal/h (38 l/hod)
Input temperature

68–300 °F (20–150 °C)

Min. shift of belt = 28.3 in/min (720 mm/min) max.time of drying 46 min
Max. shift of belt = 224.4 in/min (5700 mm/min) min. time of drying 6.15 min
Max. volume of material on belts (in box) 8.1 yd³ (6,2 m³)
Specific weight of agro material, approx. 617–705 lb/yd³ (280–320 kg/m³) box = 3,836–4,365 lb (1,740–1,980 kg)
Input moisture of material cca 50–75 %
Output moisture cca 10–20 %
Dimensions of drying box l=492 (12) × w=96 (2.3) × h=142 (3.6) in (m)
Dimensions of dryer with components l=751 (19.2) × w=174 (4.4) × h=205 (4.6) in (m)
Weight 37,258 lb (16.9 t)

Belt Dryer Assembly

  • Heat source - 2× heater, diesel fuel, light fuel oil, gas
  • Tank - fuel tank (diesel) 264.17 gal (1 m³)
  • Transport fan - 2× fan of 24 hp (18 kW)
  • Feeding conveyor - belt conveyor with hopper
  • Hopper capacity - 0.65–2.61 yd³ (0,5–2 m³)
  • Rotary dispenser - material dispenser on the belt, tourniquet
  • Drying box- enclosed heat insulated drying box with three belts, pipeline designated for distribution and circulation of drying air
  • Discharge fan - transport fan of 25 hp (18 kW)
  • Centrifugal separator- cyclone - solid particle separator
  • Rotary valve - rotary separator, tourniquet
  • Exhaust pipeline - pipeline designated for ar exhaus out of the box
  • Discharge conveyor - belt conveyor for discharge of finished dried material
  • Electrical switchboard with control system
All parts and components are made of material in a high quality according to European and American standards.

Continuous drying

Continuous drying is performed in the way that the material is continuously dosed on the drying belt (in the layer of approx. 3.9–7.9 in (10–20 cm) and material is advanced by constant adjustable speed throughout the whole process of drying. Hot air is led on material through the diffusor nozzles along the entire length all three belts by means of transport fans. Temperature of drying air can be regulated between 86–300 °F (30–150 °C) depending on required temperature. The motion of material on the belts in the drying box can be set on required speed depending on needed length of stay of the material for drying in the box.

Cyclical drying

Cyclical drying is performed in a way that the material is dosed on the drying belts in set up quantity (in the layer of approx. 3.9–7.9 in (10–20 cm) so that all three drying belts are filled in a uniform layer. Then the belts are stopped for the required time and hot air is led on the material by transport fans. Once set up for drying period, the belts are set in motion again and finished dried material is discharged out from the drying box onto the discharge conveyor. The control system allows to set any variant of the drying cycle in any period interval. For example, it is possible to set period of belt motion as well as the belt pause interval depending on output moisture.


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