Tumble Dryer Air Return Filtration for Easy Filter Access

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Solution Overview

Problem

Existing heat pump tumble dryers require significant effort and safety risks to access and clean filters, as the structural unit must be largely removed, necessitating specialized personnel and compromising safety.

Innovation Solution

A tumble dryer design with a deflection area in the air return duct allows for easy access to filters by angling the process air inlet, enabling users to clean filters without removing the heating unit, using removable covers and strategically placed filters to facilitate self-cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the heat pump circuit is arranged as a compact removable unit with horizontal insertion, then the filter can be accessed by removing the structural unit, but this requires significant effort, specialized personnel, and creates safety risks

Engineering Contradiction:
Improvefilter accessibilityVSAvoidstructural unit removal requirement
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The filter is segmented from the heat pump circuit and positioned in a separate accessible location (deflection area of air return duct). This allows the filter to be removed and cleaned independently without dismantling the entire heat pump unit, resolving the contradiction between filter accessibility and device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The deflection area serves as an intermediary space between the air return duct and the heat pump circuit. By placing the filter in this intermediate zone, it becomes accessible from the front of the appliance without requiring removal of the heat pump unit, thus maintaining both accessibility and structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the process air inlet is arranged directly vertically upwards, then the heat pump circuit can be horizontally inserted, but the filter becomes inaccessible without removing the entire unit

Engineering Contradiction:
Improvehorizontal insertion capabilityVSAvoidfilter cleaning accessibility
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The filter accessibility problem is solved by adding a new spatial dimension - the deflection area at the front of the appliance. Instead of accessing the filter only through horizontal removal of the heat pump unit, users can now access it from the front vertical dimension, maintaining both manufacturing simplicity and operational ease.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If filters are arranged in the air return duct to protect the heat pump circuit, then fluff is removed from process air, but the filters become clogged and require regular cleaning that disrupts process air flow

Engineering Contradiction:
Improveheat pump circuit protectionVSAvoidprocess air flow continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The filter is extracted from its traditional position within the heat pump circuit and relocated to the deflection area. This extraction allows the filter to be removed and cleaned without disrupting the heat pump unit or process air flow, maintaining both circuit protection and continuous operation.

Inventive Principle:
Principle #2Taking out (Extraction)

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 simplifies filter cleaning, reduces safety risks, and allows users to perform maintenance without specialized personnel, enhancing accessibility and safety while maintaining the heat pump's integrity.

Implementation Method 1

at least one filter for filtering the humidified process air is arranged between the laundry drum and the process air inlet

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

the moisture extracted from the laundry is condensed from the process air and discharged to the outside in liquid form

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

The energy extracted from the process air is fed back into the process air, so that the process air leaves the heat pump circuit in the direction of the laundry drum after being heated up again

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3118367B1Tumble dryer
Publication Date: 2018.12.05 MIELE & CO KG
  • EP3118367B1 patent drawingFigure 1
  • EP3118367B1 patent drawingFigure 2
  • EP3118367B1 patent drawingFigure 3

AI summary

The present invention relates to a tumble dryer (1), preferably a heat pump tumble dryer (1), with a laundry drum (15) for receiving laundry to be dried and a heating unit (23), preferably a heat pump unit (23), for generating heated process air for drying the laundry in the laundry drum (15), the laundry drum (15) being connected to a process air inlet (29) of the heating unit (23) by an air return duct (21) in order to heat the process air moistened by the laundry - Supply unit (23), wherein between the laundry drum (15) and the process air inlet (29) at least one filter (32, 34) for filtering the humidified process air is arranged. The tumble dryer (1) is characterized in that the air return channel (21) has a deflection area (31) in order to guide the process air to the process air inlet (29) in a deflected manner, with two filters (32, 34) being arranged in the deflection area (31). The first filter (32) is arranged at an angle (α) greater than 0° and less than 90° relative to the process air inlet (29), while the second filter (34) is arranged at an angle (β) relative to the process air inlet (29). is greater than 0 ° and smaller than the angle (α) and between the first filter (32) and the process air inlet (29) is arranged.