We can find different kind of ovens used in bakery industry as per usage, fuel availability and application
Electrical Heating : Generally this type ovens are usedfor wafer making . These ovens have trays which travelsinside the electrical oven .These trays are heatedelectrically.Carbon Brushes are contact points which transfer lelectric energy to the wafers trays .
Indirect heating: ( CNG -LPG - LDO - HSD FIRED )
Indirect Radiating (Cyclotherm)
This type of oven transfers the heat to the dough piece mainly by radiation. Its baking chamber consists of a set of tubes positioned above and below the conveyor, which transfer the heat to the dough pieces. A burner heats the hot air which is forced through the tubes by a suitable fan blower. The heat is transferred to the dough pieces mainly by radiation, and the fuel combustion products never come into contact with the dough pieces being baked. The ideal application of this method of heat transfer is when gentle baking is required, such as for the production of hard sweet, rotary moulded, wire cut or deposited biscuits. The controls available to the operator in each zone are those for the temperature of the baking chamber, top and bottom heat ratio and the extraction of moisture from the chamber. This type of heating is utilized in the hybrid oven configuration, before the convection heated section of the oven. When equipped with a slat-type conveyor, this type of oven is mainly used for baking products in metal trays, such as muffins, cakes or bread. On request, the oven can be fitted with a turbulence system which provides a further contribution to uniform baking conditions in the baking chamber. Inside the baking chamber, the conveyor whether wire mesh or metal band is supported by rollers.
Direct Heating : ( CNG - LPG - GAS FIRED )
Direct Gas Fired Oven
This powerful oven is particularly suitable for baking those products which require short baking times and high heat input especially at the beginning of their baking cycle. These include crackers (cream and soda), snacks and also some fermented products. In this type of oven, a high number of burners with flames are positioned directly in the baking chamber. The heat is transferred to the product mainly by the effect of radiation and, since there is no metal structure separating the heat source from the product, it can be considered as a high-efficiency oven in terms of heat transfer. The environment in the baking chamber is more humid than that of other types of ovens, as the combustion of the fuel generates further moisture. This humid environment prevents a skin from forming on the surface of the dough, so the piece can fully expand in height, while also ensuring more efficient extraction of further humidity from the centre of the dough piece. The number of burners installed in the baking chamber greatly depends on the type of product to be baked and the output required: cracker rated ovens are those with the highest number of burners in the baking chamber, complete with a per-heating system of the conveyor belt. Gaseous fuels, i.e. Natural gas or LPG, must be utilised for these types of burners. Top and bottom heat for each zone can be independently set by the operator simply by adjusting a potentiometer. The temperature and the extraction from each zone of the baking chamber can also be adjusted. The direct gas-fired section is utilized in the hybrid oven configuration, usually before the direct convection section of the oven, especially in the production of all types of cracker products (soda, cream, snacks) or in case of swiss roll production. The conveyor wire-mesh or metal band is supported by rollers.