Magnetic Cap Temperature Sensing for Wire-Free Cooking Vessels

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Solution Overview

Problem

Existing cooking vessels with integrated temperature sensors face challenges in automated production due to complex wire positioning and potential degradation during use, leading to measurement errors, and existing solutions do not effectively measure temperature beyond a certain threshold.

Innovation Solution

A cooking vessel with a cap made of non-magnetic materials incorporating a magnet with non-zero remanent magnetization, which varies with temperature, cooperates with a magnetic field measurement sensor to determine temperature without wires, ensuring reliable and durable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conductive wires are used to connect the temperature sensor to the control device, then the temperature measurement function is achieved, but the manufacturing complexity increases and reliability decreases due to wire degradation during assembly and overheating

Engineering Contradiction:
Improvetemperature measurement reliabilityVSAvoidwire positioning and connection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the conductive wires from the system by replacing them with a wireless magnetic field communication mechanism. The temperature sensor and control device communicate through magnetic field variations generated by the magnet, eliminating the need for physical wire connections and their associated positioning and degradation issues.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/electrical wire connection system with a magnetic field-based communication system. Instead of using conductive wires to transmit temperature data, the system uses a magnet whose magnetic field strength varies with temperature to wirelessly communicate temperature information to the control device.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If the Curie temperature of the magnet is set low for easy temperature detection, then temperature measurement sensitivity improves, but the measurement range is limited and cannot withstand high temperatures

Engineering Contradiction:
Improvetemperature measurement sensitivityVSAvoidmaximum temperature measurement range
Core Design Contradiction:
Measurement precisionVSTemperature

Solution Approach 1:

The patent changes the parameter of Curie temperature to a high value (greater than 350°C) to expand the temperature measurement range. By selecting a magnet with a high Curie temperature, the system can accurately measure temperatures across a broader range including high-temperature cooking conditions while maintaining magnetic field variability for detection.

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 solution provides a simple, economical, and reliable temperature measurement system that withstands high temperatures and is resistant to mechanical stresses, allowing for accurate temperature monitoring within the vessel's operational range.

Implementation Method 1

a magnet (10) having a non-zero remanent magnetization which varies as a function of temperature and having a Curie temperature greater than 350°C, said variation of remanent magnetization generating a variation of magnetic field

Methodology Applied
Scientific EffectTemperature-dependent remanent magnetization variation: Magnetic Hysteresis

Implementation Method 2

a magnetic field measurement sensor arranged on the periphery of the cap which generates an electric signal used in a control device to make it possible to determine the temperature of the cap

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 3

having a Curie temperature greater than 350°C... the magnet which has a Curie temperature greater than 350° C. retains its remanent magnetization

Methodology Applied
Scientific EffectCurie temperature effect: Curie Point (ferromagnetic)

Data Source

PatentEP3020313B1Cooking receptacle having a magnetic temperature measuring device
Publication Date: 2018.10.24 SEB SA
  • EP3020313B1 patent drawingFigure 1~2
  • EP3020313B1 patent drawingFigure 3~5
  • EP3020313B1 patent drawingFigure 6

AI summary

The invention relates to a cooking vessel (1) intended to be placed on a heating plate (30), a burner or the like for cooking food and comprising a cap (2) made of one or more non-magnetic materials. According to the invention, the cap (2) comprises a magnet (10) having a non-zero remanent magnetization which varies as a function of the temperature and having a Curie temperature greater than 350° C., said variation of remanent magnetization generating a magnetic field variation, and said magnet (10) is intended to cooperate with at least one magnetic field measurement sensor (22, 22a) arranged on the periphery of the cap (2) which generates an electric signal used in a control device (25) to enable the temperature of the cap (2) to be determined.