Method and device for carrying out a hygiene program and heat pump dryer

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Solution Overview

Problem

Conventional hygiene programs in heat pump dryers have long cycle times and are limited to treating damp laundry, causing mechanical and thermal stress on textiles and dryer components.

Innovation Solution

A method and device for a heat pump dryer that reduces refrigerant and process air temperatures and incorporates precise temperature and time controls to enable faster, effective hygiene programs for both dry and wet laundry, minimizing stress on components and ensuring hygiene.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional hygiene programs use high temperatures and long holding times to sanitize laundry, then hygiene effectiveness is improved, but cycle time increases and mechanical/thermal stress on components increases

Engineering Contradiction:
Improvehygiene effectivenessVSAvoidcycle time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the temperature parameter profile by using a reduced maximum temperature (e.g., 60-70°C instead of higher temperatures) combined with a specific holding time period. This parameter optimization allows achieving hygiene effectiveness while reducing cycle time and thermal stress on components.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies a preliminary drying phase before the hygiene holding phase. By pre-drying the laundry to reduce moisture content, the subsequent hygiene phase can be completed faster and at lower temperatures, thereby reducing overall cycle time while maintaining hygiene effectiveness.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If conventional hygiene programs use high temperatures and long holding times, then hygiene effectiveness is improved, but mechanical and thermal stress on textiles and dryer components increases

Engineering Contradiction:
Improvehygiene effectivenessVSAvoidmechanical and thermal stress
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes temperature and time parameters to reduce thermal stress. By using moderate temperatures (60-70°C) with controlled holding times instead of high temperatures, the patent achieves hygiene effectiveness while minimizing thermal stress on textiles and electrical components of the dryer.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The preliminary drying phase removes excess moisture before the hygiene phase, reducing the energy and time required for sanitization. This reduces both thermal stress during the hygiene phase and mechanical stress from prolonged high-temperature operation.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If conventional hygiene programs are designed for damp laundry with residual moisture control, then hygiene effectiveness is improved, but the program cannot be used for dry laundry

Engineering Contradiction:
Improvehygiene effectivenessVSAvoidlaundry type flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal hygiene program that can handle both damp and dry laundry. By using temperature and time-based control instead of residual moisture sensing, the same program parameters work effectively for both laundry types, making the hygiene function adaptable to different input conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces the residual moisture sensing mechanism with a time-based control system. Instead of using sensors to detect moisture levels and adjust program duration, the system uses a predetermined holding time that achieves hygiene effectiveness regardless of initial laundry moisture content, thereby enabling versatility across different laundry types.

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

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 solution reduces cycle times, protects dryer components and textiles, and allows for efficient processing of both dry and wet laundry with reduced mechanical and thermal stress, ensuring reliable hygiene without prolonged cycles.

Implementation Method 1

a heat pump for drying and tempering the process air

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

a heat pump for drying and tempering the process air

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

an auxiliary heating device for heating the process air

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 4

a process air blower for circulating the process air through the drum, the heat pump and the auxiliary heating device back into the drum

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP4682306A1Method and device for carrying out a hygiene program and heat pump dryer
Publication Date: 2026.01.21 MIELE & CO KG
  • EP4682306A1 patent drawingFigure 1
  • EP4682306A1 patent drawingFigure 2~3
  • EP4682306A1 patent drawingFigure 4~5

AI summary

A method for performing a hygiene program of a heat pump dryer (100), wherein the heat pump dryer (100) comprises a drum (102) for receiving laundry, a heat pump (108) for drying and tempering the process air, an auxiliary heating device (112) for heating the process air, a process air blower (110) for conveying the process air in a cycle through the drum (102), the heat pump (108) and the auxiliary heating device (112) back into the drum (102), a process air temperature sensor (134) for detecting a process air temperature of the process air on the outlet side of the drum (102) and a refrigerant temperature sensor (130) for detecting a refrigerant temperature of a refrigerant of the heat pump (108) on the outlet side of a compressor (122) of the heat pump (108), comprises a step of driving the process air blower (110) to convey the process air in the circuit,a step of controlling the compressor (122) of the heat pump (108) to set the refrigerant temperature to a reduced setpoint for the hygiene program, which is lower than a maximum setpoint for a drying program of the heat pump dryer (100), a step of operating the auxiliary heating device (112) to set the process air temperature to a preset value for the hygiene program, and a step of terminating the hygiene program after a predefined holding time has elapsed.