Thermal cooking device

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Solution Overview

Problem

Conventional thermal cooking devices using a plane heater above the ceiling wall face challenges in rapidly reaching and maintaining a preset temperature in the heating compartment due to inefficient heat transfer, safety concerns, and limited power rating, leading to prolonged cooking times and inaccurate temperature control.

Innovation Solution

The thermal cooking device incorporates a plane heater with an inner and outer heater, a three-dimensionally curved ceiling wall to maintain close contact, and a controller that manages the heaters' power to ensure rapid temperature attainment and maintenance, using a heat insulator and keep plate to absorb deformation forces and prevent overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the plane heater is used to heat the ceiling wall for indirect heating of the heating compartment, then the heating efficiency is improved, but the ceiling wall experiences repeated expansion and contraction causing clearance formation and deteriorated heat transfer efficiency

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidcontact stability between plane heater and ceiling wall
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The ceiling wall is designed with a three-dimensional curved surface that concavely faces the heating compartment, allowing the plane heater to maintain close contact throughout its entire area while accommodating thermal expansion and contraction of the ceiling wall material

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Device complexity

If the plane heater is controlled based on detected internal compartment temperature with simple on and off operation, then the control system is simple, but the preset temperature is difficult to reach with high accuracy and requires prolonged time

Engineering Contradiction:
Improvecontrol system complexityVSAvoidtemperature control accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The controller detects the internal compartment temperature and controls the plane heater's on and off operations based on this detected temperature, enabling accurate maintenance of the preset temperature through continuous feedback adjustment

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The controller dynamically adjusts the plane heater operation based on real-time temperature detection, transitioning from simple fixed on/off control to adaptive control that responds to actual temperature conditions

Inventive Principle:
Principle #15Dynamics

3Productivity

If the plane heater operates at high power to rapidly heat the heating compartment, then the heating speed is improved, but the plane heater temperature may exceed its heat resisting temperature causing safety issues

Engineering Contradiction:
Improveheating speedVSAvoidheater safety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The controller monitors the heating process and adjusts plane heater operation based on detected internal compartment temperature, preventing the heater from exceeding its heat resisting temperature while maintaining rapid heating capability

Inventive Principle:
Principle #23Feedback

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 configuration allows for rapid and accurate attainment of a preset temperature within the heating compartment, reducing cooking time and ensuring consistent temperature control while adhering to rated power limits.

Implementation Method 1

the heat from the heat source of the plane heater is transmitted to the ceiling wall through the electrically insulating member, thus heating the ceiling wall

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the interior of the heating compartment is heated to the preset temperature by heat radiated by the heated ceiling wall

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

the ceiling wall is caused by the heat of the plane heater to repeatedly experience expansion and contraction

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 4

The ceiling wall of the heating compartment has a three-dimensional curved surface concavely facing the heating compartment, and the plane heater is fixed to make close contact with the ceiling wall throughout its entire area

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3428539B1Thermal cooking device
Publication Date: 2020.06.10 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3428539B1 patent drawingFigure 1~2
  • EP3428539B1 patent drawingFigure 3~4
  • EP3428539B1 patent drawingFigure 5

AI summary

A thermal cooking device according to the present disclosure includes: a heating compartment in which a cooking object is heated; a plane heater provided above a ceiling wall of the heating compartment, the plane heater being one heat source formed of an inner heater disposed right above a central portion of the ceiling wall, and an outer heater surrounding the inner heater; and a controller that controls the inner heater and the outer heater of the plane heater. The ceiling wall of the heating compartment has a three-dimensional curved surface concavely facing the heating compartment. The plane heater is fixed to make close contact with the ceiling wall throughout its entire area.