Laundry dryer and method for drying laundry with a laundry dryer

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Solution Overview

Problem

Conventional tumble dryers often inefficiently dry laundry, as they maintain constant heat and airflow, leading to prolonged drying times and energy wastage, without effectively adapting to the moisture levels of the laundry.

Innovation Solution

A tumble dryer with a control system that adjusts temperature and airflow based on real-time moisture and temperature readings, using inductive heating for the fan rotor and separate fan drive, allowing for optimized drying by reducing heat and increasing airflow towards the end of the cycle, and adjusting drum movement to enhance moisture removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If constant heat and airflow are maintained throughout the drying cycle, then the drying process is simple to control, but energy consumption increases and drying time is prolonged

Engineering Contradiction:
Improveenergy consumptionVSAvoidcontrol system complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent implements dynamic adjustment of heating power and fan speed based on real-time moisture detection. The control system varies operational parameters throughout the drying cycle rather than maintaining constant settings, optimizing energy efficiency while adapting to changing laundry moisture levels.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs moisture sensors that continuously monitor laundry moisture levels and feed this information back to the control system. This feedback mechanism enables automatic adjustment of heating and airflow parameters, reducing energy consumption while maintaining effective drying performance.

Inventive Principle:
Principle #23Feedback

2Productivity

If high temperature is maintained throughout the drying cycle, then drying speed increases, but laundry may be damaged by excessive heat

Engineering Contradiction:
Improvedrying speedVSAvoidheat damage to laundry
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements periodic adjustment of heating temperature based on drying phase and moisture levels. High temperature is applied during early drying stages when laundry is wettest, then temperature is reduced in later stages, providing both fast drying and heat protection through time-varying thermal exposure.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent dynamically changes the temperature parameter throughout the drying cycle based on moisture sensor feedback. The control system adjusts heating power to maintain optimal drying temperature that varies with laundry moisture content, preventing heat damage while maximizing drying efficiency.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If moisture sensing is performed inside the drum, then measurement precision is improved, but device complexity and potential sensor damage increase

Engineering Contradiction:
Improvemoisture measurement accuracyVSAvoidsensor arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses air as an intermediary medium to transfer moisture information from the drum interior to external sensors. Moisture sensors are positioned in the air stream that circulates between the drum and external environment, allowing indirect moisture measurement without placing sensors inside the drum, thus reducing complexity and sensor exposure to harsh conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enables quicker, more energy-efficient drying by tailoring the drying process to the laundry's moisture levels, reducing energy consumption and protecting the laundry from excessive heat, while ensuring thorough drying.

Implementation Method 1

two induction heating coils are arranged on the valve housing, which can be controlled accordingly. You can inductively heat a part of the rotor of the fan, which is made of a suitable material, for example iron.

Methodology Applied
Scientific EffectInductive heating: Induction Heating

Implementation Method 2

a discretely designed dry sensor is provided. This can be used to determine the moisture of the laundry in the drum

Methodology Applied
Scientific EffectCapacitive humidity sensing: Capacitance

Data Source

PatentEP3608469B1Laundry dryer and method for drying laundry with a laundry dryer
Publication Date: 2023.08.30 E G O ELEKTRO GERAETEBAU GMBH
  • EP3608469B1 patent drawingFigure 1~2
  • EP3608469B1 patent drawingFigure 3
  • EP3608469B1 patent drawingFigure 4~5

AI summary

A tumble dryer consists of a drum for laundry, a drive motor for the drum, an air supply to the drum and an air exhaust from the drum, a fan with a fan drive to generate an airflow towards the drum through the air supply and away from the drum through the air exhaust, and a heating element to heat the airflow. The temperature and humidity of the air exhausted from the drum are measured. Its behavior is compared with predefined curves stored in a memory, using computational algorithms for each drying phase. This determines the operating point of the predefined curve at which the drying program is currently operating. Based on this operating point, the control system adjusts the subsequent drying program by modifying the temperature and/or airflow strength.