Susceptor Wire Induction Heating Curie Point Regulation

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Solution Overview

Problem

Induction heating systems face challenges with overheating, underheating, and uneven heating due to the high Curie point of ferrous materials, and non-ferromagnetic materials like copper and aluminum are not effectively used as they do not magnetically couple well with the magnetic field generated by induction coils.

Innovation Solution

The use of a susceptor wire made from a material with high magnetic permeability and electrical resistivity, embedded within a non-ferrous housing, which generates heat via eddy currents when exposed to a magnetic field, limiting the temperature to its Curie point and preventing overheating, and allowing for uniform heating of containers and contents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If ferrous materials are used for containers, then heating capability is improved, but temperature control becomes difficult due to high Curie point

Engineering Contradiction:

Improveheating capabilityVSAvoidcontrol system complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent changes the material parameter by using a susceptor with a specific Curie point (e.g., 1400°F) that is lower than conventional ferrous materials. This parameter change enables automatic temperature regulation because the susceptor loses magnetic properties at the Curie point, naturally limiting maximum temperature without requiring complex control systems or continuous monitoring.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If non-ferrous materials like copper and aluminum are used, then ease of operation is improved, but magnetic coupling efficiency deteriorates

Engineering Contradiction:

Improveease of useVSAvoidmagnetic coupling efficiency

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent introduces a susceptor as an intermediary component embedded in the container wall. This susceptor acts as a mediator between the induction coil's magnetic field and the non-ferrous container material. The susceptor converts electromagnetic energy to thermal energy through eddy currents and then transfers heat to the container contents via thermal conduction, enabling non-ferrous materials to be used effectively with induction heating.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If ferrous materials are used, then heating efficiency is improved, but risk of overheating increases

Engineering Contradiction:

Improveheating efficiencyVSAvoidoverheating risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of high temperature (overheating risk) into a beneficial automatic temperature regulation mechanism. The susceptor's Curie point property causes it to lose magnetic permeability at a specific temperature, which automatically reduces eddy current generation and heat production. This transforms the potential harm of overheating into a self-regulating safety feature that maintains consistent heating efficiency while preventing excessive temperatures.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 eliminates the need for complex control systems and continuous monitoring, ensuring even heating and preventing overheating or underheating, while enabling the use of non-ferrous materials like copper and aluminum in induction cooking applications.

Implementation Method 1

The magnetic field generates heat in the container or vessel via eddy currents

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The magnetic field generates heat in the container or vessel via eddy currents and the container provides heat to contents positioned in the container via thermal conduction

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 3

The susceptor wire is composed of a material having a relatively high magnetic permeability and a relatively high electrical resistivity sufficient to induce an eddy current in the susceptor wire when a magnetic field is applied to the susceptor wire via an induction source. The magnetic field generates the eddy current in the susceptor wire when a temperature of the susceptor wire is below a Curie temperature of the material of the susceptor wire. The susceptor wire limits heating to a temperature that is equal to or less than the Curie temperature.

Methodology Applied

Scientific EffectCurie point effect: Curie Point (ferromagnetic)

Data Source

PatentUS9510398B1Induction heating apparatus

Publication Date: 2016.11.29 THE BOEING CO

AI summary

Induction heating apparatus are disclosed herein. An example induction heating apparatus disclosed herein includes a housing and a susceptor wire positioned in the housing. The susceptor wire is composed of a material having a relatively high magnetic permeability and a relatively high electrical resistivity sufficient to induce an eddy current in the susceptor wire when a magnetic field is applied to the susceptor wire via an induction source. The magnetic field generates the eddy current in the susceptor wire when a temperature of the susceptor wire is below a Curie point of the material of the susceptor wire. The susceptor wire limits heating to a temperature that is equal to or less than a Curie temperature associated with the material of the susceptor wire.