Blog: Unique heating control enhances TruBake™ DGF biscuit ovens

A prime reason why Direct Gas Fired (DGF) ovens are so widely employed in the biscuit industry throughout the world is that their heating systems are extremely flexible and can be fine-tuned to make virtually any kind of biscuit successfully – from low power-demand cookies to high power-demand crackers.

Most DGF ovens offer the ability to radically adjust heating to suit each individual product. Radiant heat from ribbon burners and convective heat from turbulence ducts are applied in varying proportions along the length of the oven to achieve the ideal conditions for each product. A controllable extraction system, adjustable throughout the oven, is provided to remove products of combustion and moisture from the baking chamber.

Independent turbulence and extraction for predictable control

Baker Perkins’ TruBake™ DGF oven incorporates these capabilities, of course – plus a unique, exclusive additional control feature. Two completely separate systems handle turbulence and extraction – there is no interaction between the two, as there is in all other DGF ovens. This guarantees entirely predictable control of the oven, and elevates Baker Perkins’ TruBake™ DGF control to a higher level of precision.

The two independent systems ensure that changing the amount of air being extracted to atmosphere has no effect on the turbulence system, and altering the rate of turbulence does not change the rate of extraction.

On other ovens, these functions are combined. A single fan extracts air from the baking chamber: a proportion is drawn off to extraction and the remainder recirculates through the turbulence ducts. Adjusting the rate of extraction changes the amount of air available for turbulence, necessitating a compensating adjustment to the turbulence system.

Multiple modular baking cells control air drift

The additional level of heating control achieved in Baker Perkins’ TruBake™ DGF ovens is accomplished by a system involving separate turbulence blowing, turbulence return and chamber extraction ducts fitted in each two metre module, creating multiple baking cells along the oven.

Compared with systems that feature only a single extraction point per zone, these multipoint turbulence and extraction cells ensure that there is no uncontrolled air drifting along the length or across the width of the oven. The turbulence blowing air increases the rate of heat transfer to the product and is then recirculated.

A further refinement is separate top and bottom full width extraction, to avoid air being drawn past the sides of the oven band, which can increase heat transfer rates to the band and lead to uneven baking.

Precision design for a stable baking environment

A stable baking environment providing even baking across the full width of the oven band, with no side burning at the edges, is crucial to product consistency. In the TruBake™ DGF, whilst burners, extraction system and turbulence system function independently, they combine to secure high quality and minimal waste.

Baker Perkins’ ovens are designed with the aid of sophisticated computer modelling systems, backed by a century of experience, to ensure that airflow is managed in an efficient and predictable way. A touch screen with intuitive controls and clear display of the baking profile provides operators with all the information they need to run the oven recipe efficiently. All Baker Perkins’ ovens are Industry 4.0 Ready.

As an additional benefit, Baker Perkins’ DGF ovens have been upgraded to our TruClean™ benchmark. This is an approach to hygienic design instigated to meet a clear demand from the industry for higher standards, particularly covering access for cleaning and maintenance.

Baker Perkins' TruBake™ Direct Gas Fired Oven