Limescale Detection in Liquid Heaters Using Thermal Response Analysis

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Solution Overview

Problem

Existing liquid heating devices, such as coffee machines, suffer from limescale buildup that reduces heat transfer efficiency and operational performance, with current methods lacking accurate detection and feedback on cleaning needs.

Innovation Solution

A method to detect limescale accumulation by analyzing the thermal response of the heating system to a power pulse, using thermal sensors to measure the temperature rise of heated water, and comparing it to a reference model to determine limescale levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If limescale accumulates on the heating element, then the heater continues to operate without additional sensors or complex systems, but the heat transfer efficiency deteriorates and heating performance is compromised

Engineering Contradiction:
Improveheater operationVSAvoidheat transfer efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements a feedback mechanism by measuring the actual heating performance of the heater and comparing it to expected performance. The system monitors the temperature rise of water over time and uses this feedback to detect limescale accumulation. When degradation is detected, the system can trigger cleaning cycles or adjust operation to maintain efficiency, resolving the contradiction between continuous operation and energy loss.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-diagnosis by automatically monitoring its own heating performance without requiring external sensors or complex additional hardware. The microcontroller analyzes the heating curve generated during normal operation to detect limescale buildup, enabling the heater to self-assess its condition and initiate appropriate maintenance actions, thus maintaining reliability while preventing energy loss.

Inventive Principle:
Principle #25Self-service

2Device complexity

If no additional sensors are used to detect limescale, then the device complexity remains low, but the measurement precision of limescale accumulation is insufficient

Engineering Contradiction:
Improvesensor configurationVSAvoidlimescale detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent uses the heating process itself as an intermediary to detect limescale. Instead of directly measuring limescale with specialized sensors, the system measures the thermal response of water heating, which is affected by limescale accumulation. This indirect measurement approach maintains low device complexity while achieving sufficient measurement precision through clever use of existing operational parameters.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system replaces direct mechanical or chemical limescale detection methods with thermal field-based detection. By monitoring temperature changes and heating rates during normal operation, the system substitutes complex sensing mechanisms with simple temperature measurements and computational analysis, reducing device complexity while maintaining measurement capability.

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

3Ease of operation

If the heater operates continuously without monitoring, then the ease of operation is maintained, but the productivity is reduced due to inefficient heating from limescale buildup

Engineering Contradiction:
Improveuser interventionVSAvoidheating efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The system continuously monitors heating performance and provides feedback to the control system. This automatic feedback loop maintains ease of operation by requiring no user intervention while simultaneously improving productivity by detecting limescale accumulation and triggering cleaning cycles or operational adjustments to maintain optimal heating efficiency.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary detection of limescale accumulation during normal heating operations before significant performance degradation occurs. By continuously monitoring heating curves and detecting early signs of efficiency loss, the system can initiate cleaning or adjustment actions in advance, maintaining both ease of operation and high productivity throughout the heater's operational life.

Inventive Principle:
Principle #10Preliminary action

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

Provides precise feedback on limescale levels, enabling targeted cleaning cycles to maintain optimal heater efficiency and performance.

Implementation Method 1

a heating element configured to heat the water circulating in the coil

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

at least one thermal sensor arranged to measure a temperature of the water in the output line

Methodology Applied
Scientific EffectThermal detection: Thermocouple

Data Source

PatentEP4057875B1Method and device for detecting the amount of limescale in liquid heating devices
Publication Date: 2026.02.11 I R C A S P A IND RESISTENZE CORAZZATE E AFFINI
  • EP4057875B1 patent drawingFigure 1
  • EP4057875B1 patent drawingFigure 2
  • EP4057875B1 patent drawingFigure 3

AI summary

A method and device for detecting the amount of limescale that accumulates in liquid heating devices, in particular for heating water. The method is capable of establishing, through simple temperature measurements, if the amount of limescale deposited on the heater element of a device for heating liquids is such as to jeopardize the correct operation thereof and provides the user with information on the need to clean the aforesaid heater.