Microwave Roasting Oven with Rotating Support and Susceptor
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Solution Overview
Problem
Current coffee roasting methods, including convection, conduction, and steam roasting, face challenges such as non-uniform heating, thermal runaway, and the inability to achieve mixed roasts, leading to issues like burning, smoke generation, and high energy costs, while microwave roasting struggles with hot-spot heating and thermal runaway, resulting in suboptimal flavor and safety concerns.
Innovation Solution
A microwave oven with a rotating support and variable power level, coupled with a susceptor layer and high-velocity fans, allows for controlled roasting of low-moisture foods like coffee beans, enabling uniform or non-uniform roasting profiles through programmable angular velocity and power adjustments, along with a high-intensity lamp for monitoring and automatic shutdown to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If convection heating is used to roast coffee beans, then uniform roasting is achieved, but coffee oils are stripped away through evaporative loss
Solution Approach 1:
The patent uses a sealed roasting chamber that creates a controlled environment where coffee beans are roasted without excessive air circulation. This prevents the evaporative loss of coffee oils while maintaining uniform heat distribution through the sealed enclosure and controlled heating elements.
2Manufacturing precision
If conduction roasting is used with a rotating drum, then beans are agitated to prevent scorching, but lighter coffee oils are lost through air circulation
Solution Approach 1:
The patent employs a sealed roasting chamber that minimizes air circulation during the roasting process. This eliminates the loss of lighter coffee oils through air circulation while maintaining uniform roasting through the design of the heating elements and bean agitation mechanism within the enclosed space.
3Productivity
If steam roasting is used with superheated steam, then roasting speed is increased, but sour flavor is produced and high pressure creates safety hazards
Solution Approach 1:
The patent controls the temperature and pressure parameters within the sealed roasting chamber to achieve fast roasting without producing sour flavors or safety hazards. By precisely managing the thermal parameters and maintaining controlled pressure conditions, the system achieves rapid roasting while avoiding the harmful effects of superheated steam.
4Use of energy by moving object
If microwave energy is applied to roast low-moisture foods, then heating efficiency is improved, but hot-spot heating and thermal runaway occur
Solution Approach 1:
The patent employs periodic or pulsed microwave energy application rather than continuous exposure. This periodic action allows heat to distribute more evenly throughout the food material, preventing hot-spot formation and thermal runaway while maintaining the high heating efficiency advantage of microwave technology.
5Productivity
If high temperature is used to roast beans quickly, then roasting time is reduced, but outer surfaces are burned while inner regions are under-roasted
Solution Approach 1:
The patent uses periodic microwave energy application combined with bean agitation to achieve fast roasting with uniform results. The periodic heating cycles allow heat to penetrate and distribute evenly throughout the beans, preventing surface burning while ensuring thorough roasting of the inner regions.
Solution Approach 2:
The patent incorporates dynamic bean agitation during the roasting process to ensure uniform exposure to heat sources. This movement of beans during periodic heating cycles prevents localized overheating and ensures consistent roasting throughout the batch, achieving both speed and uniformity.
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
This solution provides uniform roasting with reduced thermal runaway, minimizing energy consumption and smoke production, while allowing for precise control over roast levels and flavors, enhancing the quality of roasted coffee beans.
Implementation Method 1
a microwave source, the roasting interval during which the rotating support and microwave source are operative
Implementation Method 2
a rotating support oriented substantially perpendicular to the door, the rotating support having attachment points for insertion of a container with food items to be roasted
Implementation Method 3
coupled with a susceptor layer and high-velocity fans, allows for controlled roasting
Implementation Method 4
coupled with a susceptor layer and high-velocity fans
Data Source
AI summary
A roasting oven includes an enclosure coupled to a source of microwave RF energy, an operable door for sealing the enclosure for RF, the operable door having a viewing aperture which prevents the escape of RF from inside the chamber. A rotating support has an axis which is perpendicular to the viewing aperture such that the progress of roasting may be viewed through the viewing aperture and into a food container placed in the rotating support. The applied power of the microwave RF source and the rotational velocity of the rotating support are selected to provide uniform or wide spectrum roasting of the food item. A roasting profile may include a roasting interval during which the microwave RF source and rotating support are both energized, and subsequently a cool-down interval where the microwave RF source is disabled and the rotating support continues to rotate.