Microwave Heating Device Phase Shift Control

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Solution Overview

Problem

Existing microwave heating techniques face challenges in achieving homogeneous temperature distribution within food products and among multiple identical loads, leading to non-uniform heating results.

Innovation Solution

A microwave heating device with a control unit that adjusts the frequency and phase shifts of microwaves emitted by multiple radiating portions to create a 'stirring' effect, optimizing operational configurations for improved spatial uniformity by calculating energy efficiency and selecting operating frequencies that minimize efficiency differences or standard deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If electromagnetic heating techniques (microwave or RF) are used to achieve shorter thawing or cooking times, then heating speed is improved, but temperature distribution uniformity deteriorates

Engineering Contradiction:
Improveheating speedVSAvoidtemperature distribution uniformity
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the microwave radiating portions movable or adjustable in position and orientation. The radiating portions can be repositioned during the heating process to change the microwave distribution patterns dynamically, thereby achieving more uniform temperature distribution while maintaining rapid heating speeds throughout the food product.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs parameter changes by varying the frequency, phase, and amplitude of microwaves emitted by different radiating portions. By controlling these parameters independently for each radiating portion, the system can optimize both heating speed and temperature uniformity through adaptive adjustment of electromagnetic field characteristics.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If multiple identical loads are heated simultaneously, then productivity is improved, but temperature uniformity among loads deteriorates

Engineering Contradiction:
ImproveproductivityVSAvoidtemperature uniformity among loads
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by providing individual control over each radiating portion's microwave emission. This allows the system to create localized heating zones tailored to the specific position and characteristics of each load, ensuring that multiple loads receive appropriate microwave energy distribution for uniform heating while maintaining high productivity through simultaneous processing.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs segmentation by dividing the heating system into multiple independently controllable radiating portions. Each radiating portion can be individually adjusted to target specific loads or regions, enabling precise control over temperature distribution across multiple simultaneous loads and thereby maintaining uniformity while improving overall productivity.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If microwave generating system uses fixed frequency and phase configuration, then device complexity is reduced, but heating uniformity deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidheating uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by implementing controllable phase shifters and frequency modulators that can adjust the microwave characteristics dynamically. These components, while adding some complexity, enable adaptive control of the electromagnetic fields to achieve superior heating uniformity that outweighs the moderate increase in device complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs parameter changes through the use of adjustable phase and frequency controls for each radiating portion. By enabling independent modification of these parameters, the system can optimize heating uniformity for different food products and configurations, achieving high manufacturing precision in temperature distribution while maintaining manageable device complexity through standardized control mechanisms.

Inventive Principle:
Principle #35Parameter changes

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 method achieves favorable spatial uniformity in heating, particularly when multiple identical loads are heated simultaneously, by adaptively adjusting microwave distribution patterns within the heating chamber.

Implementation Method 1

a microwave generating system (20) including at least two radiating portions (25) adapted to radiate microwaves to the heating chamber (12)

Methodology Applied
Scientific EffectMicrowave radiation: Microwave Radiation

Implementation Method 2

the microwave generating system (20) generates and radiates, via the at least two radiating portions (25), respective microwaves having a same frequency and different phases

Methodology Applied
Scientific EffectPhase shift: Phase Modulation

Implementation Method 3

heat is generated directly inside the food product by means of electromagnetic fields or electromagnetic radiations

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Data Source

PatentEP3525550B1Microwave heating device and method for operating a microwave heating device
Publication Date: 2021.08.04 ILLINOIS TOOL WORKS INC
  • EP3525550B1 patent drawingFigure 1~2
  • EP3525550B1 patent drawingFigure 3~4
  • EP3525550B1 patent drawingFigure 5~6

AI summary

This disclosure relates to a microwave heating device and a method for operating a microwave heating device, in particular to heat at least one product inside a heating chamber of the device. The microwave heating device comprises at least two radiating portions that are adapted to radiate microwaves to the heating chamber and can be operated according to a plurality of operational configurations that differ in frequency and/or in phase shift(s) between the radiated microwaves. A learning procedure can be executed by sequentially operating the at least two radiating portions in several operational configurations. Energy efficiency data are calculated for those operational configurations. An operating frequency can be selected via an algorithm that optimizes a mathematical function based on energy efficiency data. An operational configuration with a maximum energy efficiency at the selected operating frequency may be taken as a reference. A heating procedure can be executed by sequentially operating the at least two radiating portions in operational configurations having the selected operating frequency and respective phase shift(s) that are chosen around the respective phase shift(s) of the reference operational configuration.