Indirect Teflon-Belt Tunnel Oven BKR T
The “indirect” heated oven (Bakerunner) is powered by one or more gas burners, in this way the heated air is moved around in the heating circuit thus transmitting the heat to the final product in the required way.
The baking inside the tunnel happens by means of heat radiation, heat convection (contact with baking surface) and/or heat conduction (Turbolence).
1. The oven project
This is an innovating oven with huge potential. The Teflon coated band as baking surface has advantages that are unique, among which are the following:
- It allows to bake any product with topping or extremely sticky without sticking to the baking surface and without getting dirty; a scraper is enough to keep the band clean: this way it is possible to avoid baking paper or Teflon coated trays and the relative conveying circuit.
- It releases the heat immediately and having no mass it heats up and cools down instantly.
- Teflon is neutral, from the food point of view.
- The band is light and easy to be replaced: it can be jointed by means of a rack strip.
2. Technical characteristics
2.1 Baking profile/regulation
The oven is divided in baking zones each with independent regulations, the max length of a zone is 6 meters.
The main regulations on the side of the oven are:
- Top heat regulation;
- Bottom heat regulation;
- Oven heat regulation at infeed;
- Steam exhaust regulation;
- Steam infeed regulation at oven infeed;
- Hot air circuit blower speed regulation;
- Turbolence blower speed and direction regulation;
- Baking speed regulation;
- Burner flame regulation (only by means of PLC).
During the baking the regulation happens by means of opening or closing the dampers to adjust the amount of heat or steam entering or exiting the heating circuit and by changing the speed and/or temperature parameters on the control panel.
This oven is designed to work with automatic heat dampers.
2.2 User Interface/An intelligent oven
From the operator panel the supervisor can manage the baking process completely.
The oven is equipped with different sensors, the acquired data allow the operator to verify the progress of the process and even the baking efficiency. The main sensors are:
- Hot Gas temperature at infeed channel;
- Hot Gas temperature in the return channel;
- Hot gas temperature at chimneys exit;
- Pressure inside the hot gas circuit;
- Opening of the burner gas flow valve;
- Sensor of humidity in the chamber (optional).
It is possible to put several parameters (SET-points) and verify the actual status (IS); alarms are showed with an explanation and position on the line; the maintenance page advises about maintenance status of the different components; the recipes page can memorize the baking parameters of the different products.
The oven automation level can be increased according to the customer requirements, it is actually possible to manage automatically the baking profile of the oven automatizing the heat-dampers and/or the steam extraction dampers in the different zones; in this way the operator can set up the oven for the different product types simply by choosing the correct recipe on the control panel.
Moreover with this system it is possible to detect the product gap inside the oven and modify the baking conditions accordingly.
It is clear that by combining some of the data acquired by the sensors and knowing the product hourly output it is possible to determine the energetic efficiency of the oven together with other productivity coefficients.
3. Some details
Turbulence
It is a baking zone where hot air is moved towards the product by two blowers positioned on the opposite sides of the baking chamber. The air flow is adjustable (lateral inclination) through a lateral opening, the flow speed is adjustable. The turbulence can be switched off, in that case the baking chamber works as a “neutral” chamber.
Automatic tensioning of the band
Band tensioning is in control of a pneumatic cylinder.
Automatic tracking device
Band tracking device: by means of two side actuators on a swiveling-roller the band is constantly guided.
Automatic dampers
Hot air and steam dampers can be motorized. The motor positions the dampers to the exact opening position according to the active recipe. This option is particularly helpful to manage the product gap and avoid the oven overheating (flash heat).
Inspection door
The new inspection door design allows a better access inside the oven for cleaning and maintenance purposes.
Extraction blowers
If required forced extraction blowers can be mounted on the hot steam extraction chimneys. They allow controlling of the steam conditions in the chambers and as well as managing the production gaps in a better way.