Variable-Speed Convection Oven Control to Reduce Baking Crust
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Solution Overview
Problem
Conventional convection ovens often produce undesirable crusts or glazing on baked goods, such as breads and cakes, during the cooking process, which is not effectively addressed by existing technologies.
Innovation Solution
A cooking appliance with a convection heating system that includes a motor-driven fan and a controllable switch, controlled by a microprocessor, which regulates fan speed and heating element intensity to minimize undesirable crusting or glazing by using phase angle firing and zero-crossing detection for precise speed control of the fan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If convection cooking is used to cook food quickly, then cooking speed is improved, but undesirable crust or glazing forms on baked goods
Solution Approach 1:
The patent applies dynamics by making the fan speed variable rather than fixed. The controller adjusts fan speed dynamically based on the cooking cycle phase and selected cooking mode, allowing the system to optimize between convection effectiveness and minimizing crust formation. This is achieved through a variable speed fan controlled by a microprocessor that receives inputs from sensors and adjusts operation accordingly.
Solution Approach 2:
The patent changes the operational parameters of the convection system by implementing variable fan speeds across multiple predetermined speeds rather than operating at a single high speed. The controller modifies fan speed parameters based on cooking stage, food type, and desired outcome, thereby adjusting the balance between cooking efficiency and surface quality of baked goods.
2Stability of the object's composition
If high fan speed is used for convection cooking, then heat distribution is improved, but crusting or glazing on baked goods worsens
Solution Approach 1:
The system dynamically adjusts fan speed based on real-time conditions and cooking phase. During phases when uniform heat distribution is critical, higher fan speeds are employed. During phases where surface quality is prioritized, fan speed is reduced. This dynamic adjustment allows the system to maintain heat distribution stability while minimizing harmful surface effects.
Solution Approach 2:
The controller implements periodic variation in fan speed during the cooking cycle, alternating between higher speeds for heat distribution and lower speeds for surface quality preservation. This periodic action pattern allows the system to achieve both objectives at different times during the cooking process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The appliance effectively cooks food quickly while reducing undesirable properties like crusting or glazing on baked goods by optimizing fan speed and heating element control, ensuring better cooking outcomes for various food types.
Implementation Method 1
A conventional oven uses radiant heating provided by bake and/or broil heating elements to cook food placed within the oven
Implementation Method 2
A convection oven has a fan for developing convective air flows within the oven, and can cook food more quickly than a comparable conventional oven
Data Source
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AI summary
A cooking appliance includes a cabinet forming an oven cavity, and bake and broil heating elements. A convection system develops a flow of heated air within the cavity. The convection system includes a motor-driven fan, a convection heating element, and a controllable switch for controlling an electrical power circuit for the motor. A user interface device allows user selections of convection bake and convection roast operations. A controller communicates with the interface device and controls activations of the fan and the heating elements. The controller has an output for controlling operations of the controllable switch. During convection baking, the controller activates the bake and convection heating elements and controls the controllable switch so that the fan runs at a first speed. During convection roasting, the controller activates the bake and convection heating elements and controls the controllable switch so that the fan runs at a second, higher speed.