Most popular type of Ovens used in biscuit Industry are Hybrid Ovens where Direct Heating and Indirect Heating are used.Heaters are placed on top and bottom of oven band .
It is a common experience to notice that the type and amount of heat required by a dough piece being baked varies throughout the baking process. Usually a great amount of heat is required when baking starts, in order to obtain a lifting effect in the dough piece. Once its structure is established, then a drying effect must take place, and the amount of heat required is more gentle. For these reasons the typical configuration of a hybrid oven consists of radiating heat at the beginning (Direct Gas-Fired or Cyclotherm), followed by convection heating toward the end of the baking process. Different types of heat can in fact have different effects on the final product. Imaforni was one of the first in the sector to experiment and promote the baking process using mixed-heat ovens in the early 1980s. The range of oven sections that can be configured for the creation of a hybrid oven is as follows: · direct gas fired with or without turbulence · indirect gas fired Cyclotherm with or without turbulence · direct or indirect convection
The advantages that can be obtained by using hybrid-configured ovens rather than traditional single heat transfer systems, could be summarised as follow: · flexibility of the baking process different products which require different baking profiles can easily and successfully be processed in the same oven · much more precise control over the final moisture content of the products · moisture uniformity within each piece is enhanced, thereby reducing the danger of checking effects on products · crispness and general texture of the products are improved · more uniform colour of all the baked products across the width · in most cases higher output levels are obtainable.
The hybrid oven configuration has been successfully adopted by many major bakeries in different parts of the world; indeed, they have been using this hybrid configuration for the baking process of their major brands for more than two decades now. This important confirmation obtained directly from the field has clearly revealed the advantages and the reliability of these technological solutions. In the biscuit and cracker sectors these applications have cbeen created for working belt widths of up to 1700 mm, and for baking chambers up to 120 metres long.