Heating control with reduced temperature overshoots for an iron and corresponding method

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Solution Overview

Problem

Ironing devices with simple thermostats face challenges in controlling temperature due to thermal inertia, leading to temperature overshoots that can damage delicate garments.

Innovation Solution

Incorporating alternating heating and non-heating phases with strategically timed power interruptions, controlled by a thermostat unit and switch element, to reduce thermal inertia effects and prevent temperature overshoots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If continuous heating is applied to reach target temperature quickly, then heating speed is improved, but temperature overshoots occur due to thermal inertia of the soleplate

Engineering Contradiction:
Improveheating speedVSAvoidtemperature overshoot
Core Design Contradiction:
SpeedVSTemperature

Solution Approach 1:

The patent applies periodic action by implementing alternating heating phases and non-heating phases during the heating process. The control unit interrupts power supply at strategically determined moments within the heating phase, creating periodic on-off cycles that allow the soleplate temperature to equilibrate and prevent overshoot while maintaining overall heating progress.

Inventive Principle:
Principle #19Periodic action

2Device complexity

If simple mechanical thermostat is used, then device complexity is reduced, but temperature control precision deteriorates due to inability to compensate for thermal inertia

Engineering Contradiction:
Improvethermostat complexityVSAvoidtemperature control precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by having the control unit determine and plan power interruption moments in advance during the heating phase. This preliminary timing allows the system to proactively compensate for the soleplate's thermal inertia before temperature overshoot occurs, enabling simple mechanical thermostats to achieve precise temperature control.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If power supply is interrupted frequently to control temperature, then temperature control precision is improved, but heating efficiency deteriorates

Engineering Contradiction:
Improvetemperature control precisionVSAvoidheating efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies partial action by implementing selective power interruptions only during specific moments within the heating phase, rather than continuous or frequent interruptions. The control unit determines optimal interruption moments that provide sufficient temperature control precision while minimizing the total duration of power interruptions, thus maintaining heating efficiency.

Inventive Principle:
Principle #16Partial or excessive 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

This approach stabilizes the heating process, reduces temperature overshoots, and provides more accurate temperature control, even in irons with mechanical thermostats, thereby protecting garments from damage.

Implementation Method 1

a heating element thermally coupled with the soleplate

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the detrimental effects caused by the thermal inertia of the soleplate

Methodology Applied
Scientific EffectThermal inertia: Inertia

Data Source

PatentEP3409828B2Heating control with reduced temperature overshoots for an iron and corresponding method
Publication Date: 2024.10.30 SDA FACTORY VITORIA S L U
  • EP3409828B2 patent drawingFigure 1
  • EP3409828B2 patent drawingFigure 2
  • EP3409828B2 patent drawingFigure 3

AI summary

An iron is described. The iron comprises a soleplate, a heating element thermally coupled with the soleplate and a thermostat unit configured for controlling operation of the heating element, the thermostat unit being configured for alternatingly effecting heating phases and non-heating phases of the heating element. The iron further comprises a switch element adapted for switching a power supply of the heating element and a control unit adapted for controlling a switching operation of the switch element. The control unit is configured for assigning a respective time pattern defining one or more power interruption intervals to at least one selected heating phase of said heating phases, with the switch element being configured for interrupting power supply of the heating element during the one or more power interruption intervals in accordance with the respective time pattern.