Cyclotherm or Radiant Heated Tunnel Ovens

The Multibake® R Tunnel Oven by AMF Den Boer is an indirect heated oven (Radiation) for industrial bakeries. The required heat is generated outside the baking tunnel preventing hot gases from coming into contact with the baking product. This heating system is also known as ‘Cyclotherm’ or heat cycle.

The oven is divided into zones or sections. Within each zone, different temperature and humidity conditions are possible. This makes it possible for each zone to have a different function: rising of the products, baking, and coloring of the products. Depending on the product to be baked, forced convection, either from the top or the bottom of the product can be added to the execution. 

This oven is also available with a Dual Fuel Option featuring independent heating systems within the same oven.

Efficient Heat Transfer

In the bottom part of the first baking zone, ribbed tubes ensure more efficient heat transfer for this radiant oven. Relative to cold trays and products, the ribbed tubes deliver heat to the core of the dough in the first stage of baking. The steam supply, fitted in steam module of 1100 mm, is located in front of the first oven module. This module contains pre-heated ribbed tubes for heat transfer to the pans/trays and two steam lances to extend the time of a wet surface on the product for excellent volume and shine.

What is the Cyclothermic Configuration?

The circulation fan (5) blows hot gases at high speed through the tubes of the parallel connected radiators (6 and 7). The hot gases heat these tubes. The tubes heat the baking chamber and the products by radiation and conduction. The circulation fan extracts the cooled gases. A small part is exhausted to the open air. The rest is transported to the mixing chamber (1). These gases are heated to the desired temperature through intensive mixing with fresh combustion gases.

The radiators are controlled separately by regulating valves to create the desired baking curve. The regulating valves are active across the entire width of the oven. Therefore, even with different radiator loads, a uniform heat emission is possible. Almost all ducts and radiators have a slight vacuum to prevent gases from leaking into the baking chamber.

Key Features

  • Hygienic design of the industrial tunnel oven with complete oven framework, including infeed/outfeed terminals, free from the bakery floor.
  • Modular concept of pre-assembled modules and 100% electrical testing at AMF Den Boer prior to shipping ensures a very short installation and start-up.
  • Optional top or bottom convection (even both in one zone) provides controllability of heat transfer to the product with more even baking and colouring of the products.
  • Industrial Honeywell (Maxon) burners with a control ratio of 36:1 (300 kW) and 25:1 (600kW) giving a wide span of operation and reliable control.
  • Integrated temporary setpoint reduction in case of small gaps in the production flow.
  • Several options are available for Energy Management and Moisture Measurement

Simple Operation and Maintenance

Engineered with Allen-Bradley or Siemens PLC controls, the Multibake® R Tunnel Oven is easy to operate and maintain. Each module can be executed with a hinged door or service hatch in order to allow you to easily enter the tunnel for maintenance, cleaning, or inspection. The modular configuration makes the Multibake® R very easy to extend in a later stage. By adding a certain amount of modules, service teams can increase oven capacity in a matter of days.


Soft Bread and Buns
Tin Bread and Lidded Bread
Rusk, Biscottes

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