Laundry Drum Air Opening Design to Reduce Flow Loss and Noise
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Solution Overview
Problem
Conventional laundry drums in tumble dryers experience flow losses and turbulence due to air openings, leading to higher energy consumption and noise emissions.
Innovation Solution
The design features a laundry drum with a wall having multiple air openings of varying diameters, a flat or convex surface, and collars that reduce the cross-section of the openings, improving airflow and allowing for smaller fans and energy savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air openings are provided in the drum wall for process air flow, then drying function is enabled, but flow losses and turbulence occur leading to higher energy consumption and noise
Solution Approach 1:
The patent applies parameter changes by modifying the geometry of air openings from simple circular holes to funnel-shaped openings with reduced cross-section. The opening cross-section decreases from the outer drum surface toward the interior, creating a tapered structure that optimizes airflow parameters. This geometric parameter change reduces turbulence and flow losses while maintaining the necessary air intake for the drying function.
Solution Approach 2:
The patent implements local quality by providing different surface characteristics at different locations. The outer drum surface features a flat or convex surface quality between air openings to minimize turbulence, while the air openings themselves have a specialized funnel shape with varying cross-section. This localized optimization of surface quality and opening geometry reduces overall flow losses while preserving the drying function.
2Reliability
If air openings are provided in the drum wall for process air flow, then drying function is enabled, but turbulence is generated leading to higher noise emissions
Solution Approach 1:
The funnel-shaped air openings with progressively reducing cross-section modify airflow parameters to reduce turbulence intensity. The tapered geometry guides air flow more smoothly into the drum interior, minimizing chaotic eddies and vortex formation that generate noise. This parameter optimization maintains adequate air intake for drying while significantly reducing noise emissions.
Solution Approach 2:
The patent employs curved surfaces in the form of funnel-shaped openings with smooth transitions. The curved, tapered geometry of the air openings replaces sharp edges and abrupt transitions with gradual curvature, which reduces flow separation and turbulence. This application of spheroidality/curvature principles minimizes the generation of harmful noise while preserving the drying function.
3Ease of manufacture
If conventional air openings are used in the drum wall, then manufacturing is simple, but flow losses occur reducing drying efficiency
Solution Approach 1:
The funnel-shaped air openings with varying cross-section represent an optimization of geometric parameters that improves drying efficiency. While more complex than simple circular holes, the funnel shape can be manufactured using standard forming processes for metal or plastic drums. The improved airflow characteristics resulting from this parameter change lead to better drying efficiency that outweighs the moderate increase in manufacturing complexity.
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 enhances airflow efficiency, reducing energy consumption and noise emissions while maintaining a smooth airflow path.
Implementation Method 1
the air openings in particular lead to flow losses and/or turbulence in the process air flow
Implementation Method 2
the cross section (i.e. diameter) of at least one of the air openings reduces at least in a section from the outside of the drum to the inside of the drum
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The washing drum has air openings (21) that are formed in a wall (20) which divides inner space (11) and outer space (12) such that air flow (13) from inner space to outer space is possible. A convex surface is formed between the air openings whose cross-sectional area is gradually reduced from outer surface to inner surface. The wall is partially comprised of a metal sheet.