The Air Handling and Drying Unit, DAHU ( Dessicant Air Handling Unit), is a completely automatic machine that generates a filtered, low humidity, and at set controlled temperature, for food processes.

The drying process is carried out by means of a SILICA GEL ROTOR, installed in the unit, and thanks to adsorption principle, adsorbs humidity contained in the air that pass through, achieving an extremely dry air at the outlet of it.

It is remarkable the hygienic design, the accessibility to all elements and the high energy efficiency of it.


Air flows: from 100 m3/h to 20.000 m3/h.

Absolute humidity: 1,5 g/kg or its equivalent 25ºC and 8 %RH.

It is the ideal solution for food industry applications that requires a filtered, temperature and humidity-controlled air.

Typical applications that require a very dry air, are automatic coating (that is produced in our BOMBO), or in the chocolate lentils forming ( produced in our FORMINGPLUS), or to humidity control in cooling tunnels KALTENPLUS, injecting dry air.

Process can be completely automatized, and all adjustments of the machine are set from Touch Screen HMI integrated in it.

  • Custom- made design for each application: airflow, air pressure, humidity and temperature are the parameters to define in project.
  • Hygienic design, completely manufactured in stainless steel, for maximum ease of cleaning.
  • Supported over frame manufactured in stainless steel AISI304L.
  • Aluminum profiles structure modular.
  • Removable closings of the unit, by means of insulating panels, in polyurethane of high density 40 mm thickness. Optionally panels are manufactured in complete stainless steel.
  • Air Filtration (Process air and regeneration air), in 3 stages as standard. Being the most common, G4,F7 and F9 efficiency, achieving a 99% efficiency of particle filtration. Each Filtration stage is equipped with differential pressure manometers and pressure switches, that generates an alarm when it is needed a filter replacement. Optionally can be added an absolute filter H13 or similar.

What define DAHU

  • In process air, after filtration, it is normally installed a PRE COOLING STAGE, completely automatic, air is cooled down to 10ºC, to dry it, by passing through a heat exchanger cooled down by means of cold water / glycol from factory, and automatically controlled by means of control valve.
  • Process air then pass through the SILICA GEL ROTOR, where looses humidity caused by adsorption of the humidity. The rotor is rotating continuously at low speed, driven by its own motor and belt.
  • At outlet of SILICA GEL ROTOR, process air is very dry and hot, so now is necessary to install a temperature control stage, by 2 heat exchangers: POST COOLING AND POST HEATING, where automatically the air temperature is set.
  • In POST COOLING stage, the process air is cooled down by means of cold water / glycol, from factory main line and controlled by a temperature sensor that regulates the control valve located in cooling media.
  • In POST HEATING stage, the process air is heated up by means of hot water/ steam, from factory main line, and controlled by temperature sensor thar regulates the control valve located in heating media.
  • Process air is moved by means of centrifugal ventilator, directly coupled, located in the unit, and sized according to the process.
  • Process air Flow is adjustable by means of frequency inverter that drives the ventilator.
  • Process air is then filtered, dried and at set temperature, according to process.
  • For a correct working of the air drying by means of SILICA ROTOR, it is necessary a second airflow, called REACTIVATION or REGENERATION AIR. The purpose of this airflow is to dry the Silica rotor, that is saturated by humidity coming from process air, allowing a continuous working cycle.
  • The REGENERATION AIR flow is filtered, same as process air, is filtered in 3 filtration stages usually (G4, F7 and F9). Normally the regeneration air flow is the third part of the process air flow.
  • After filtration, REGENERATION AIR is heated up in a heat exchanger by means of steam, up to 130ºC. Later the airflow passes through the rotor, evaporating the water contained in it, and driving this humid air to outside. This is how the rotor is REACTIVETED/ REGENERATED.
  • REGENERATION AIR, is blown by means of a centrifugal ventilator, with direct coupling installed in the unit.
  • Electrical cabinet integrated, with PLC and Touch Screen HMI, for precise control of all parameter in some models.


  • HEAT RECOVERY SYSTEM. With the purpose of increasing energy efficiency of the unit DAHU, the regeneration air at outlet of the unit ( usually hot and humid air), can be recirculated to a static plates heat exchanger, in order to heat up previously the regeneration air entering the unit, decreasing the steam consumption needed for the unit.
  • FULLY STAINLESS STEEL. The unit can be configured to be completely manufactured in stainless steel including the closing insulating panels.

What Is DAHU Used For.​


The cooling tunnel KALTENPLUS designed and manufactured by FECOATEC, is a completely automatic machine for controlled cooling of different food products.


The forming rollers line FORMINGPLUS is a completely automatic machine for the production of lentils, spheres, hearts, eggs or other shapes in chocolate, compound or food paste ( sesame paste, peanut paste…) in a continuous way.


The automatic coating pan BOMBO, designed and manufactured by FECOATEC, is a completely automatic machine for syrup or chocolate coating of several food products.

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