Direct-Fired Tunnel Ovens
The Multibake® D Tunnel Oven by AMF Den Boer is a direct heated oven for industrial bakeries. The required heat is created directly in the baking tunnel by means of modulating multi-ribbon gas burners. There are four burners in each standard module: two burners directly above and two burners underneath the products to be baked. The construction of the baking tunnel, divided into modules, guarantees an even heat transfer to the product.
Burners will have their service side on the right or left hand side of the oven, when viewed in baking direction.
- Dependable, adjustable heat transfer from bottom and top
- Moisture monitoring and steam injection as an option
- Automatic gap detection
- Optional convection unit provides air movement between the burners
- Diffusor pipes surrounding the top burners provides a gentle bake by radiation of the tubes.
- Heat transfer from the combustion gases of the burners towards the product is direct without any transfer losses.
The modulating burners consist of a specially rolled and profiled pipe, fitted over its entire length with a stainless steel corrugated strip burner bed. Each burner is equipped with an electrically operated double gas valve and an air supply valve, an ignition pin, which also serves as an ionization pin, and a local burner control unit. These control units ensures ignition of the burner, gas valve control and flame monitoring. The burners are operating following a zero gas pressure system.
The temperature is measured in each zone, both underneath and above the product to be baked.
PT-100 sensors are fitted in the baking tunnel for this purpose. The measured values for each zone can be read on the central control panel (touch panel).
To achieve the desired baking curve the required temperatures for each zone can be set on the central control panel. The burners are controlled via a processor system. In this way, it is possible to control the top and bottom temperature in each zone. If the set temperature deviates from the measured temperature, the modulating burners are subsequently adjusted by means of P.I.D. temperature regulators, which regulate the burners infinitely until the set temperature is reached. In this way, the desired baking curve can be achieved.
Added to the above mentioned, an automatic gap detection is available which can prevent color differences on the edges of the product and provide a stable bake despite incidental stoppages during the normal flow of production.