Laundry Dryer Temperature Control for Heat-Sensitive Fabric Protection

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Solution Overview

Problem

Conventional laundry treatment apparatuses can damage laundry with poor heat tolerance during drying, as they rely on a single heater control method that does not differentiate between pre-dryness and post-dryness hot air supply control, leading to potential damage and increased drying time.

Innovation Solution

A control method for a laundry treatment apparatus that includes a drum, an air supply path with a heating unit, temperature and dryness sensing units, and distinct heating unit control procedures based on dryness levels, adjusting temperature thresholds and heater operations to prevent damage and optimize drying time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single heater control method is used for drying laundry, then the drying process is simple to operate, but laundry with poor heat tolerance may be damaged

Engineering Contradiction:
Improveheater control simplicityVSAvoidlaundry damage from heat
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The drying process is segmented into two distinct phases: a first drying phase using first reference temperatures and a second drying phase using second reference temperatures. This segmentation allows different temperature control strategies to be applied at different stages, protecting heat-sensitive laundry while maintaining drying effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reference temperatures are changed based on the drying phase. The control unit switches from first reference temperatures (higher) during the first drying phase to second reference temperatures (lower) during the second drying phase. This parameter change adapts the heating intensity to the laundry's heat tolerance requirements at different drying stages.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If heater operation is stopped when drum temperature reaches upper limit and restarted at lower limit, then energy consumption is reduced, but drying time increases

Engineering Contradiction:
Improveheater energy consumptionVSAvoiddrying time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The heater control operates dynamically by continuously monitoring drum temperature and adjusting heater operation accordingly. The control unit compares real-time temperature with reference temperatures and adjusts heater on/off timing, optimizing the balance between energy consumption and drying time through adaptive control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The temperature sensing unit provides continuous feedback to the control unit about the drum's internal temperature. This feedback loop enables the control unit to make real-time decisions about heater operation, ensuring energy-efficient control while maintaining effective drying progress by preventing premature heater shutdown.

Inventive Principle:
Principle #23Feedback

3Productivity

If conventional heater control is used, then general laundry drying is effective, but laundry with poor heat tolerance suffers damage

Engineering Contradiction:
Improvedrying effectiveness for general laundryVSAvoidheat damage to sensitive laundry
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

Different temperature control qualities are applied to different drying phases. The first drying phase uses higher reference temperatures suitable for general laundry, while the second drying phase uses lower reference temperatures specifically tailored for heat-sensitive laundry. This local quality differentiation protects sensitive materials while maintaining overall drying effectiveness.

Inventive Principle:
Principle #3Local quality

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 method effectively dries laundry with poor heat tolerance without damage and minimizes drying time by varying hot air supply control strategies based on dryness levels, ensuring safe and efficient drying.

Implementation Method 1

a heating unit disposed in the air supply path and configured to heat air

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a temperature sensing unit configured to sense an internal temperature of the drum

Methodology Applied
Scientific EffectThermal sensing:

Implementation Method 3

a dryness sensing unit configured to measure a dryness of the laundry stored in the drum

Methodology Applied
Scientific EffectElectrical resistance measurement: Electrical Resistance

Data Source

PatentEP3348706B1Control method of laundry treatment apparatus and laundry treatment apparatus performing the same
Publication Date: 2019.07.17 LG ELECTRONICS INC
  • EP3348706B1 patent drawingFigure 1
  • EP3348706B1 patent drawingFigure 2
  • EP3348706B1 patent drawingFigure 3

AI summary

A control method of a laundry treatment apparatus is disclosed which includes a hot air supply procedure for supplying heated air to a drum through operation of a heating unit, a dryness measurement procedure for measuring dryness of laundry, a first heating unit control procedure executed when the measured dryness is lower than a reference dryness, to complete operation of the heating unit when the measured temperature reaches a first temperature and to operate the heating unit when the measured temperature reaches a second temperature lower than the first temperature, and a second heating unit control procedure executed when the measured dryness is equal to or higher than the reference dryness, to complete operation of the heating unit when the measured temperature reaches a third temperature lower than the second temperature and to operate the heating unit when the measured temperature reaches a fourth temperature lower than the third temperature.