Laundry drying unit having a lint screen arranged within a process air circuit and a method for operating said laundry drying unit

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Solution Overview

Problem

Laundry drying devices face issues with cleaning liquid overflow during the cleaning process, leading to potential overflow in the lint depot and inefficient absorption of particles, due to variable condensate water levels and pressure.

Innovation Solution

A laundry drying device with a controllable valve system, actuated by a control device that calculates and releases only the necessary amount of cleaning liquid based on sensors for load, humidity, temperature, and textile type, ensuring precise control of the cleaning liquid volume and flow duration to prevent overflow and optimize cleaning efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the valve opening time is fixed regardless of condensate level, then the device structure is simple, but the cleaning fluid volume varies causing overflow in the lint depot

Engineering Contradiction:
Improvevalve control systemVSAvoidcleaning fluid volume
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The valve opening time is made dynamic rather than fixed. The control device adjusts the valve opening duration based on real-time condensate level detection, allowing the system to adapt to varying fluid volumes and prevent overflow in the lint depot while maintaining effective cleaning.

Inventive Principle:
Principle #15Dynamics

2Reliability

If more cleaning fluid is released to ensure effective cleaning, then cleaning performance is improved, but the risk of overflow in the lint depot increases

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidoverflow risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system implements feedback control where the condensate level is continuously monitored and this information feeds back to the control device, which adjusts the valve opening time accordingly. This ensures that the optimal amount of cleaning fluid is released for effective lint removal while preventing excessive fluid release that would cause overflow.

Inventive Principle:
Principle #23Feedback

3Object-affected harmful factors

If the condensate tray volume is increased to prevent overflow, then overflow risk is reduced, but the device occupies more space and becomes more complex

Engineering Contradiction:
Improvecondensate overflowVSAvoidcondensate tray volume
Core Design Contradiction:
Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The system performs preliminary action by detecting the condensate level before the overflow point is reached and adjusting the valve opening time in advance. This proactive control prevents overflow without requiring an oversized condensate tray, maintaining compact device dimensions.

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 solution prevents cleaning liquid overflow, allows for precise control of cleaning liquid volume, and enhances the absorption of particles, reducing the risk of overflow and enabling a more uniform washing volume, while maintaining effective cleaning performance with minimal fluid consumption.

Implementation Method 1

a cleaning fluid from the rinsing tank is discharged by means of a controllable valve to the component to be cleaned

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

the cleaning fluid is also used to transport the lint from the filter to a reservoir

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 3

in this reservoir, the lint and condensate are separated again by filtration

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP2406420B1Laundry drying unit having a lint screen arranged within a process air circuit and a method for operating said laundry drying unit
Publication Date: 2022.01.19 BSH HAUSGERATE GMBH
  • EP2406420B1 patent drawingFigure 1
  • EP2406420B1 patent drawingFigure 2

AI summary

The invention relates to a laundry drying unit (W) having a component (EV; FS) to be cleaned arranged within a process air circuit and having a washing tank (SB) above the component to be cleaned (EV; FS), wherein a cleaning fluid can be dispensed onto the component to be cleaned (EV; FS) from the washing tank (SB) through a controllable valve (VT1) and wherein the valve (VT1) can be controlled on the basis of a volume of cleaning fluid in the washing tank (SB).