Ventilated Washer-Dryer Drum With Closed-Air Condenser Cooling

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Solution Overview

Problem

Existing washer-dryers face challenges in preventing undesirable leaks of process air and ensuring effective ventilation, particularly during drying processes, while also needing to comply with regulations that require efficient moisture collection and safe freshwater usage, including the need for a 'free air gap' to prevent liquid backflow and ensuring adequate ventilation in case of emergencies.

Innovation Solution

The washer-dryer incorporates an indirectly cooled condenser with a separate spray device connected to a free air path and a ventilation duct, which creates a closed circuit with the water supply line to prevent leaks and allows for efficient condenser cleaning, using an air-cooled condenser and a heat pump for energy-efficient drying, and includes a siphon to manage vapor and odor, ensuring reliable pressure equalization and moisture collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a water-cooled condenser is used to cool the air flow, then cooling efficiency is improved, but the risk of liquid backflow into the fresh water supply increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidrisk of liquid backflow
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent introduces an intermediary substance (condensate or other liquid) to cool the condenser instead of using fresh water directly. The spray device applies this liquid to the condenser surface, allowing heat exchange without creating a direct liquid pathway that could enable backflow into the fresh water supply. This mediator approach maintains cooling function while eliminating the backflow hazard.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the cooling function from the fresh water supply system by using a separate liquid source (condensate collection) to cool the condenser. This separation removes the condenser cooling operation from the fresh water distribution system, thereby eliminating the backflow risk while preserving the thermal exchange function.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of repair

If a spray device is added to clean the condenser, then cleaning capability is improved, but device complexity increases

Engineering Contradiction:
Improvecleaning capabilityVSAvoiddevice complexity
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The spray device is designed to serve multiple functions: it cleans the condenser surface of accumulated lint and debris, and simultaneously provides the liquid medium necessary for cooling the condenser. By combining cleaning and cooling functions in a single device, the patent avoids adding separate complex systems while achieving both objectives.

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

Solution Approach 2:

The system uses the condensate collected during the drying process as the cooling liquid for the condenser. This self-service approach means the system cools itself using its own waste product, eliminating the need for external fresh water supplies and reducing the complexity of water management systems.

Inventive Principle:
Principle #25Self-service

3Loss of substance

If an indirectly cooled condenser is used, then fresh water consumption is reduced, but the device complexity increases

Engineering Contradiction:
Improvefresh water consumptionVSAvoiddevice complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The patent recovers the condensate that would otherwise be discarded and uses it as the cooling medium for the condenser. This recovery approach eliminates fresh water consumption for cooling purposes while utilizing the accumulated moisture from the drying process, thereby reducing substance loss without requiring complex external water management systems.

Inventive Principle:
Principle #34Discarding and recovering

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 design effectively prevents undesirable leaks of moist process air, conserves freshwater, and ensures safe and efficient operation by maintaining a closed air circuit and allowing for effective condenser cleaning, meeting regulatory requirements for moisture collection and safety.

Implementation Method 1

a condenser with an associated spray device for spraying the condenser with a liquid

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

a heater for heating the air flow

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

a fan for driving an airflow from an inlet to an outlet through the drying duct

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Data Source

PatentEP2110473B1Washer-dryer with a ventilated drum
Publication Date: 2018.06.13 BSH HAUSGERATE GMBH
  • EP2110473B1 patent drawingFigure 1
  • EP2110473B1 patent drawingFigure 2
  • EP2110473B1 patent drawingFigure 3

AI summary

The washer dryer (1) has a caustic solution container (2) and a drum (3) rotatable arranged in caustic solution container for the admission of clothes (4). A condenser (16) is provided for indirect cooling of an air flow, and a sprayer (21) is provided, which separates one of the drying channels (14,15,17,18,19). A ventilation channel (20) is connected with a free clearance (24) and a rinsing housing (7) relevant to the water inlet strand (5,6,8,9,10).