Laundry Dryer Drum Air Inlet Control for Reverse Rotation

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Solution Overview

Problem

Tumble dryers with fixed drum rear walls and rotating drum shells face inefficiencies in process air flow due to constant air resistance and uneven drying, leading to suboptimal energy consumption and drying times.

Innovation Solution

The method involves alternating the direction of drum rotation and dynamically adjusting the position and size of the air-inflow area on the drum rear wall to optimize air flow, with a focus on positioning the inflow area below the drum's longitudinal axis and using multiple partial areas to maintain efficient air flow during both normal and reverse operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the drum rear wall is fixed with constant air inflow area, then the device structure is simple, but the process air flow efficiency is suboptimal and energy consumption is high

Engineering Contradiction:
Improvespecific energy consumptionVSAvoidair flow control system complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the air inflow area variable instead of fixed. The control device dynamically adjusts the position and size of the air-guiding inflow area on the drum rear wall based on drum rotation direction and drying phase, optimizing process air flow efficiency and reducing energy consumption throughout the drying cycle.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of the inflow area by varying its position and effective cross-section. The control device modifies the air-guiding inflow area's location on the drum rear wall and its active air-carrying total cross-section according to operating conditions, thereby optimizing process air flow characteristics and energy efficiency.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the inflow area position is fixed, then the device structure is simple, but the drying uniformity is poor due to constant air resistance

Engineering Contradiction:
Improvedrying uniformityVSAvoidinflow area adjustment mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent makes the inflow area position dynamic rather than fixed. The control device adjusts the position of the air-guiding inflow area on the drum rear wall according to the drum rotation direction and drying phase, ensuring optimal process air flow distribution and uniform drying results throughout the drying process.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by positioning the air-guiding inflow area at specific locations on the drum rear wall that are optimized for different operating conditions. The control device selects appropriate inflow positions and adjusts the active cross-section to create locally optimized air flow patterns that improve overall drying uniformity.

Inventive Principle:
Principle #3Local quality

3Productivity

If the process air flow rate is high, then the drying speed is fast, but the energy consumption increases

Engineering Contradiction:
Improvedrying speedVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by varying the process air flow rate according to different drying phases. The control device adjusts the active air-carrying total cross-section of the inflow area during the drying cycle, providing higher flow rates when needed for faster drying and lower flow rates to conserve energy, thereby optimizing the balance between productivity and energy consumption.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the process air flow rate parameter dynamically. The control device modifies the active air-carrying total cross-section of the air-guiding inflow area based on drying phase and load conditions, optimizing the balance between drying speed and energy consumption throughout the drying process.

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

This approach reduces energy consumption, shortens drying times, and ensures uniform drying by adapting the process air introduction to the drum's rotation direction, maintaining optimal air flow and contact with laundry, even during reverse operation.

Implementation Method 1

the local position of which is changed by a control device in dependence on an alternating reversal of the direction of rotation of the drum shell such that the inflow area changes at least predominantly in that part of the rear wall of the drum in front of which the laundry falls down due to the force of gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3138951B1Assembly and method for feeding process air into a drum of a laundry drier
Publication Date: 2019.03.13 BSH HAUSGERATE GMBH
  • EP3138951B1 patent drawingFigure 1~4
  • EP3138951B1 patent drawingFigure 5~7

AI summary

The invention relates to an arrangement and a method for introducing process air into the drum of a clothes dryer, wherein the clothes dryer drum 3 comprises a drum shell 4 rotatable about a longitudinal axis 5 and a stationary drum rear wall 30, wherein the drum rear wall 30 has at least one inlet area 40, 41, 42 through which process air 15 flows into the clothes dryer drum 3, and wherein the local position 51, 52, 53 of the inlet area 41, 42 can be changed by means of a control device 33. In order to further optimize the process air flow and thus the performance or efficiency of the clothes dryer, it is provided that the direction of rotation 45 of the drum shell 4 can be reversed as required, and that the control device 33 changes the position of the air-conducting inlet area 40, 41, 42 depending on the direction of rotation 50, 60.