4. Food industry

4.1 Performance

Heat is exchanged between the oven and the products by radiation (heat emitted by a hot wall), convection (transfer by hot air) and conduction (transfer by the oven belt). Monitoring the baking of cookies, for example, shows that the product development phase is essentially linked to conduction transfers, the browning phase to radiation transfers, while convection is mainly involved in drying. Under these conditions, oven performance in the food industry is linked to two key points.

• Oven control. Continuous ovens must be divided into different heating zones, each with two temperature controllers, one for top heat, the other for bottom heat. Thermocouples must be correctly positioned in the oven and checked regularly....