Method for heating a liquid with detection of the boiling point

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Solution Overview

Problem

Existing cooking devices struggle with reliable boiling point detection, especially in closed cooking chambers, leading to inefficient energy use, excessive steam formation, and difficulties in maintaining desired boiling intensity.

Innovation Solution

A method using high-frequency measuring radiation to detect the boiling point by calculating and evaluating the scattering parameter over time, allowing for reliable detection in both open and closed cooking environments through changes in the liquid's geometry caused by boiling movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If infrared radiation measurement is used for boiling point detection, then the detection can be implemented on cooktops, but the detection does not work reliably for different pots and is not usable in enclosed cooking chambers

Engineering Contradiction:
Improveapplicability to different pots and cooking chamber typesVSAvoidreliability of boiling point detection
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces optical measurement methods (infrared radiation) with electromagnetic radiation measurement at higher frequencies (microwave range). This substitution enables the measurement system to penetrate enclosed cooking chambers and work with different pot materials, as the higher frequency radiation interacts with the liquid's dielectric properties rather than relying on thermal radiation from the pot bottom surface.

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

Solution Approach 2:

The patent makes the measuring system universal by using microwave-frequency electromagnetic radiation that can function both in open cooktop environments and enclosed cooking chambers. The system measures the complex permittivity of the liquid, which is a fundamental property independent of the container type, thereby achieving multi-functionality across different cooking device configurations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If continuous high power heating is applied in enclosed cooking chambers, then the liquid reaches boiling point, but excessive steam formation occurs causing condensation and difficult-to-clean residue

Engineering Contradiction:
Improveheating efficiencyVSAvoidsteam formation and condensation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent implements feedback control by continuously monitoring the liquid's heating state through electromagnetic radiation measurement. The system detects the boiling point by identifying changes in the liquid's complex permittivity and automatically adjusts the heating power accordingly. This feedback mechanism prevents excessive steam formation by reducing power input when boiling is detected, thereby eliminating condensation and residue problems while maintaining heating efficiency.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the heating parameter dynamically by adjusting the power input based on the detected boiling state. The system transitions from high-power heating to reduced-power maintenance heating when boiling is detected, optimizing energy efficiency and preventing harmful steam accumulation in enclosed chambers.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If high-frequency measuring radiation is used for boiling point detection, then reliable detection is achieved in both open and enclosed chambers, but the system complexity increases

Engineering Contradiction:
Improvereliability of boiling point detectionVSAvoidcomplexity of measuring system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent reduces system complexity by making the measuring radiation serve multiple functions: it both heats the liquid (in microwave ovens) and detects the boiling point through permittivity measurement. This multi-functionality eliminates the need for separate heating and measurement systems, particularly in microwave cooking devices where the same electromagnetic field performs both roles.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements self-service by using the liquid's own electromagnetic properties (complex permittivity) as the measurement parameter. The liquid's response to the applied microwave radiation provides direct information about its thermal state, eliminating the need for external sensors or complex measurement apparatus that would otherwise be required to detect temperature or boiling conditions.

Inventive Principle:
Principle #25Self-service

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

Enables precise and reliable boiling point detection, allowing for efficient energy use, reduced steam formation, and controlled cooking processes, even in closed chambers, with the added benefit of using the same high-frequency radiation for both heating and measurement.

Implementation Method 1

high-frequency measuring radiation is emitted to and received by a measuring system, directed towards the liquid or into the cooking chamber containing the liquid

Methodology Applied
Scientific EffectElectromagnetic radiation reflection: Reflection

Implementation Method 2

A scattering parameter is calculated by comparing the emitted and received measuring radiation

Methodology Applied
Scientific EffectScattering: Scattering

Implementation Method 3

The liquid is heated by at least one treatment unit, which is equipped with a suitable heating source... high-frequency radiation, which is also used to heat the liquid, particularly in a microwave oven

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 4

high-frequency radiation, which is also used to heat the liquid, particularly in a microwave oven

Methodology Applied
Scientific EffectElectromagnetic heating: Electromagnetic Induction

Implementation Method 5

detection of a boiling point of the liquid... boiling movements, which are recorded by means of one or more high-frequency measurements

Methodology Applied
Scientific EffectBoiling: Boiling

Implementation Method 6

A phase change during the thawing of a frozen object is also mentioned as a process status

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP3324123B1Method for heating a liquid with detection of the boiling point
Publication Date: 2019.11.13 MIELE & CO KG
  • EP3324123B1 patent drawingFigure 1
  • EP3324123B1 patent drawingFigure 2~3
  • EP3324123B1 patent drawingFigure 4~5

AI summary

The present invention relates to a method for operating a cooking device (1) and a cooking device (1). A liquid is heated with at least one treatment device (2). In order to detect the boiling point, a measuring system (3) transmits high-frequency measuring radiation to the liquid and receives it again and uses it to determine at least one scattering parameter. A change in the scattering parameter over time is determined and evaluated. A boiling point is recognized when the change in the scattering parameter over time is characteristic of boiling movements of the liquid and, for example, of rising bubbles.