Washer-Dryer Dry Heat Sterilization for Temperature-Sensitive Laundry

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Solution Overview

Problem

Existing methods for sterilizing temperature-sensitive laundry items are inadequate as they either damage the fabric or require excessive energy, as they often involve high-temperature washing or drying processes that can cause discoloration, fabric damage, and inefficient energy use.

Innovation Solution

A method involving exposing dry laundry to a defined temperature air stream for a specified time, followed by cooling to a significantly reduced temperature, and then washing, which is implemented in a washer-dryer unit with temperature control and timing features to ensure gentle disinfection without water exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-temperature washing is used to sterilize laundry, then germ killing effectiveness is improved, but fabric damage and discoloration occur

Engineering Contradiction:
Improvegerm killing effectivenessVSAvoidfabric damage and discoloration
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary sterilization action by exposing dry laundry to hot air at temperatures of 90-110°C for a specified time before washing. This preliminary high-temperature treatment kills germs effectively, and then the laundry is cooled and washed at lower temperatures, avoiding fabric damage from prolonged high-temperature washing while maintaining sterilization effectiveness.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If hot air treatment is applied to damp laundry for disinfection, then germ killing is improved, but energy consumption increases due to heating water content

Engineering Contradiction:
Improvedisinfection effectivenessVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent performs the disinfection action preliminarily on dry laundry before washing. By treating the laundry in a dry state, the system avoids the energy-intensive process of heating and evaporating water from damp laundry, significantly reducing energy consumption while achieving effective disinfection.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If high-temperature drying is used after washing to sterilize laundry, then germ killing is improved, but fabric shrinkage and damage occur

Engineering Contradiction:
Improvesterilization effectivenessVSAvoidfabric shrinkage
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The patent applies sterilization as a preliminary action during the drying phase at lower temperatures, followed by cooling to room temperature before washing. This approach achieves sterilization without subjecting the fabric to high-temperature conditions that would cause shrinkage, as the high-temperature exposure is brief and occurs in a controlled manner followed by cooling.

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

This method effectively kills germs while being gentle on the fabric, preventing discoloration and shrinkage, and reduces energy consumption by using dry heating, allowing for efficient disinfection and subsequent washing without fabric damage.

Implementation Method 1

the items of laundry are exposed to a process air flow at a defined temperature (Tp) and heated in the dry state for a specified period of time (T)

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 2

the items of laundry heated in this way are brought to a target temperature (Tpsoll) that is significantly reduced compared to the temperature (Tp) cooled

Methodology Applied
Scientific EffectThermal cooling: Cooling

Data Source

PatentEP2707533B1Method for sterilizing laundry, and washing-drying unit
Publication Date: 2015.03.11 BSH HAUSGERATE GMBH
  • EP2707533B1 patent drawingFigure 1~2
  • EP2707533B1 patent drawingFigure 3

AI summary

The method according to the invention for sterilizing temperature-sensitive laundry items (1) comprises the following steps: in the dry state, the laundry items are exposed to a process air flow (14) having a defined temperature Tp and over a specified time period, then the laundry items (1) heated in such a way are cooled to a target temperature Tptarget significantly lower than the temperature Tp, and then the cooled laundry items (1) are washed in a washing process. The washing-drying unit according to the invention has a control device (CTRL) for carrying out said method.