Washer-Dryer Process Air Duct Self-Cleaning Using Water-Air Mixture

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Solution Overview

Problem

The existing methods for cleaning the process air duct in washer-dryers are insufficient in removing fluff accumulation, which affects air circulation and heat exchange, particularly in the heat exchanger, and require additional water consumption and complex setups.

Innovation Solution

A method involving the introduction of an aqueous liquid into the tub and transition part, combined with an air flow generated by the blower, to create a water-air mixture that effectively cleans the process air duct, including the heat exchanger, without additional water consumption and integrating seamlessly into washing or rinsing programs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If water is introduced into the process air duct to clean fluff accumulation, then cleaning effectiveness improves, but water consumption increases and device complexity increases

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidwater consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The washing machine's existing water and air systems are utilized to clean the process air duct during normal washing operations. The water pump, heater, and blower are repurposed to generate a water-air mixture that flows through the duct to remove fluff accumulation, eliminating the need for separate cleaning resources or systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The cleaning function is merged with the existing washing and drying operations. The water-air mixture generation combines the water supply system and air circulation system into a unified cleaning mechanism, allowing simultaneous water delivery and air flow through the process air duct during regular machine operation.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If additional cleaning systems are added to the process air duct, then cleaning effectiveness improves, but device complexity increases

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The water pump, heater, and blower serve dual purposes: their primary functions for washing and drying operations, and a secondary function for cleaning the process air duct. This multi-functionality allows the cleaning system to be integrated into existing components rather than requiring separate dedicated cleaning devices.

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

Solution Approach 2:

The washing machine cleans itself by utilizing its own operational systems. The water and air circulation mechanisms that normally serve the washing and drying functions are redirected to also perform maintenance cleaning of the process air duct, eliminating the need for external or additional cleaning equipment.

Inventive Principle:
Principle #25Self-service

3Reliability

If water flow rate is increased to improve fluff removal, then cleaning effectiveness improves, but energy consumption increases

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

Solution Approach 1:

The system dynamically adjusts water flow rate and air flow rate based on operational conditions. During phases requiring enhanced fluff removal, parameters are optimized to increase cleaning effectiveness while minimizing energy consumption. The heater temperature and blower speed are modulated to match the actual cleaning needs rather than operating at constant high levels.

Inventive Principle:
Principle #35Parameter changes

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 provides an efficient and water-conserving means to clean the process air duct and heat exchanger, enhancing air circulation and heat exchange efficiency while being easily integrated into conventional washer-dryer operations.

Implementation Method 1

generating an air flow with a flow rate vair in the process air duct (5) by means of the blower (6)

Methodology Applied
Scientific EffectAir flow generation:

Implementation Method 2

bringing the air flow (17) into contact with the liquid (11) in the tub (1) and in the transition part (25), so that a mixture (15) of liquid and air is formed

Methodology Applied
Scientific EffectMixture formation:

Implementation Method 3

cleaning the process air duct (5) using the mixture

Methodology Applied
Scientific EffectFluid spray cleaning: Fluid Spray

Implementation Method 4

there is a heater for heating air

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 5

a heat exchanger and a transition part between heat exchanger and tub are located

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP2611959B1Method for cleaning an air path in a washer/dryer, and washer/dryer suitable for this purpose
Publication Date: 2017.10.11 BSH HAUSGERATE GMBH
  • EP2611959B1 patent drawingFigure 1
  • EP2611959B1 patent drawingFigure 2

AI summary

The invention relates to a method for cleaning a process air channel 5 in a washer/dryer, wherein the washer/dryer has a washing tub 1, a drum 2 which is mounted rotatably in the washing tub 1 for receiving laundry items 3, a control device 18 and the process air channel 5, in which a heater 7 for heating air, a fan 6, a heat exchanger 8 and a transition part 25 between the heat exchanger 8 and the washing tub 1 are situated. The method comprises the following steps: (a) provision of an aqueous liquid 11 in the washing tub 1 and in the transition part 25, with the result that a proportion Qaq of a cross section Qtot of the transition part 25 is taken over by the liquid 11; (b) generation of a process air stream 17 of air which is situated in the process air channel 5, at a flow speed vair, by means of the fan 6; (c) bringing the air flow 17 into contact with the liquid 11 in the washing tub 1 and in the transition part 25, with the result that a mixture of the liquid and the air 15 is formed, wherein the proportion Qaq and the flow speed vair of the process air stream 17 are selected in such a way that the mixture 15 is produced in such a way that it does not take up the cross section Qaw = Qtot - Qaq which is not filled with the liquid 11 in the transition part 25; and (d) cleaning of the process air channel 5 by means of the mixture. Moreover, the invention relates to a washer/dryer which is suitable for carrying out this method.