Defrosting apparatus with respositionable electrodes

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Solution Overview

Problem

Conventional capacitive food defrosting systems face inefficiencies due to variations in food load size, leading to uneven defrosting results, as the impedance changes during the process and power transfer is not optimized for different load sizes.

Innovation Solution

A thermal increase system with repositionable electrodes and bus bars, supported by shelf structures, which adjusts impedance matching based on RF energy parameters to ensure efficient energy absorption across varying load sizes, using a variable impedance matching network and standoff isolators to maintain effective RF energy distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional fixed electrodes are used in capacitive defrosting systems, then the system structure is simple, but defrosting efficiency deteriorates due to variations in food load size and impedance changes

Engineering Contradiction:
Improvedefrosting efficiencyVSAvoidelectrode system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the electrodes repositionable rather than fixed. The electrodes can be moved to different positions and orientations to accommodate varying food load sizes and shapes. This dynamic adjustment capability allows the system to maintain optimal defrosting efficiency across different loading conditions without requiring complete system redesign.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by introducing a variable impedance matching network that dynamically adjusts impedance parameters based on the detected food load characteristics. The system measures impedance changes during defrosting and modifies electrical parameters (impedance, power level) in real-time to optimize energy transfer and maintain defrosting efficiency despite variations in load size.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If fixed power transfer is used during defrosting, then the control system is simple, but energy absorption becomes uneven across different load sizes

Engineering Contradiction:
Improveuniformity of defrostingVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies feedback by continuously monitoring impedance changes during the defrosting process and using this information to adjust power transfer and impedance matching parameters. The system measures the electrical impedance of the food load at different stages and modifies operating parameters accordingly, creating a closed-loop control system that ensures uniform defrosting across varying load sizes.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system dynamically adjusts power levels and impedance matching based on real-time measurements of load characteristics. Rather than using fixed power transfer, the system adapts its control parameters during operation to maintain optimal energy absorption and achieve uniform defrosting results.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If impedance is not adjusted during defrosting, then the system operation is simple, but power transfer efficiency decreases as food load thaws

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidimpedance control complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent implements parameter changes by dynamically adjusting impedance matching parameters during the defrosting process. As the food load thaws and its electrical properties change, the system modifies impedance parameters to maintain optimal power transfer efficiency throughout the entire defrosting cycle.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses impedance sensing feedback to detect changes in food load properties during defrosting and automatically adjusts impedance matching parameters in response. This closed-loop approach ensures that power transfer efficiency is maintained despite the changing electrical characteristics of the thawing food.

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 approach enables efficient and even defrosting by dynamically adjusting impedance to match changing load conditions, ensuring consistent energy absorption and improved defrosting performance across different load sizes.

Implementation Method 1

a radio frequency signal source electrically connected to one or both of the first repositionable electrode and the second repositionable electrode via the first bus bar and the second bus bar, respectively, the radio frequency signal source being configured to provide radio frequency energy to either or both of the first repositionable electrode and the second repositionable electrode

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Data Source

PatentEP3668275B1Defrosting apparatus with respositionable electrodes
Publication Date: 2022.07.13 NXP USA INC
  • EP3668275B1 patent drawingFigure 1
  • EP3668275B1 patent drawingFigure 2
  • EP3668275B1 patent drawingFigure 3

AI summary

A defrosting system includes a radio frequency (RF) signal source, at least one electrode proximate to a cavity within which a load to be defrosted is positioned, a transmission path between the RF signal source and the electrode, at least one bus bar in the transmission path that includes multiple ports to which the electrode may be coupled, a repositionable shelf that is attached to the electrode, and multiple support structures disposed at side-walls of the cavity that support the repositionable shelf. Standoff isolators may attach the electrode to the repositionable shelf and may electrically isolate the electrode from the repositionable shelf. The vertical position of the electrode may be changed by moving the repositionable shelf to be supported by different support structures of the multiple support structures while coupling the electrode to a different port of the multiple ports of the bus bar.