Curved Diffuser Air Duct to Reduce Tumble Dryer Pressure Loss

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Solution Overview

Problem

Existing tumble dryer diffusers are inefficient due to their flat and wide design, which causes 90° changes in the process air flow direction, reducing flow velocity and increasing energy consumption.

Innovation Solution

A diffuser with a curved air duct that minimizes changes in air flow direction, reducing pressure loss and allowing the fan to operate at a lower speed while maintaining the same flow rate, thus reducing energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the diffuser is designed to be flat and wide to accommodate limited installation space, then the installation space constraint is satisfied, but the process air flow direction changes by 90° twice which reduces flow velocity and increases energy consumption

Engineering Contradiction:
Improveenergy consumptionVSAvoidflow velocity
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent applies curvature to the air duct by designing it with a curved course instead of straight sections with sharp angles. The curved air duct gradually changes the flow direction from the fan inlet to the drum outlet, avoiding abrupt 90° deflections. This curved geometry reduces flow separation and maintains higher flow velocity while still fitting within the limited installation space at the rear of the laundry drum.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Productivity

If the fan performance is increased to compensate for flow volume loss due to deflection, then the flow rate is maintained, but the energy consumption increases contrary to efforts to reduce overall energy consumption

Engineering Contradiction:
Improveflow rateVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent changes the geometric parameters of the air duct from straight sections with sharp deflection angles to a curved configuration. This parameter change optimizes the flow characteristics, reducing turbulence and pressure losses. As a result, the fan can maintain the required flow rate with lower power consumption because the curved duct preserves flow velocity and reduces the energy dissipation that would otherwise require compensation through increased fan performance.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If 90° changes of direction are implemented in the diffuser, then the air flow is directed into the laundry drum, but the flow velocity is reduced and pressure loss increases

Engineering Contradiction:
Improveair flow direction controlVSAvoidpressure loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The curved air duct replaces sharp 90° angular deflections with gradual curved transitions. This curvature allows the air flow to change direction smoothly from the fan inlet orientation to the drum outlet orientation, maintaining higher flow velocity throughout the duct. The gradual directional change reduces flow separation and minimizes pressure losses compared to abrupt angular deflections.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 curved diffuser design enhances air flow efficiency, reduces energy consumption, and minimizes noise and vibrations, while maintaining effective dehumidification and heating of textiles.

Implementation Method 1

The air duct is designed to be arranged at the rear of the laundry drum in a household appliance, wherein the air duct has a curved course from the inlet to the outlet, wherein the at least one outlet is oriented towards the laundry drum due to the curved course of the air duct.

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentEP4556620A1Flow-optimised diffuser
Publication Date: 2025.05.21 BSH HAUSGERATE GMBH
  • EP4556620A1 patent drawingFigure 1
  • EP4556620A1 patent drawingFigure 2
  • EP4556620A1 patent drawingFigure 3

AI summary

The invention relates to a diffuser for guiding a process air flow generated by a fan into a laundry drum, comprising an air duct with an inlet for introducing the process air flow into the air duct and comprising at least one outlet for discharging the process air flow from the air duct. The air duct is designed to be arranged at the rear of the laundry drum in a household appliance. The air duct has a curved profile from the inlet to the outlet, the at least one outlet being oriented in the direction of the laundry drum due to the curved profile of the air duct. The invention further relates to an arrangement and a household appliance.