Offset Water Tray Layout for Quieter Hand Dryers

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Solution Overview

Problem

Conventional hand dryers produce noise due to direct collisions between high-speed airflow and the water receiving part, as airflow not hitting the hands maintains its speed and collides with the water receiving part.

Innovation Solution

The hand dryer design positions the water receiving part offset from the airflow direction, allowing high-speed airflow to bypass it and reducing noise while effectively collecting water droplets blown away from hands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the water receiving part is positioned in the direction of the high-speed airflow from the nozzle to receive water droplets, then water droplet collection efficiency is improved, but noise is increased due to direct collision between airflow and the water receiving part

Engineering Contradiction:
Improvewater droplet collection efficiencyVSAvoidnoise
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The water receiving part is positioned laterally offset from the airflow direction, changing the spatial arrangement from a one-dimensional alignment (directly in airflow path) to a two-dimensional configuration where the water receiving part is offset in the lateral direction. This allows the airflow to pass by the water receiving part without direct collision, reducing noise while still enabling water droplet collection through the offset positioning.

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

Solution Approach 2:

The invention introduces a lateral offset position as an intermediary spatial arrangement between the nozzle and water receiving part. Instead of direct alignment, the offset positioning acts as a mediator that allows the airflow to reach water droplets indirectly while preventing direct impact on the water receiving part, thus reducing noise generation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If the water receiving part is offset from the airflow direction to reduce noise, then noise is reduced, but water droplet collection efficiency may be compromised

Engineering Contradiction:
ImprovenoiseVSAvoidwater droplet collection efficiency
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

By positioning the water receiving part in a laterally offset position rather than directly in the airflow path, the system utilizes lateral spatial arrangement to capture water droplets that are carried sideways by the airflow. This dimensional change maintains collection efficiency while preventing direct airflow impact that causes noise.

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

Solution Approach 2:

The water receiving part is positioned at a specific lateral offset location where water droplets naturally tend to travel after being blown off the hands. This localized positioning optimizes the balance between noise reduction and water droplet collection by placing the receiver exactly where it is needed - offset enough to avoid noise but close enough to capture droplets.

Inventive Principle:
Principle #3Local quality

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 configuration enables efficient collection of water droplets while minimizing noise from airflow collisions, enhancing user experience by reducing unwanted noise during and after hand drying.

Implementation Method 1

a nozzle (10) for blowing out high-speed airflow

Methodology Applied
Scientific EffectHigh-speed airflow: Jet

Implementation Method 2

a water receiving part (4) for collecting water droplets blown away by the high-speed airflow

Methodology Applied
Scientific EffectWater droplet collection: Sedimentation

Implementation Method 3

moisture on the surfaces of the hands is evaporated during a second drying process

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3281573B1Hand dryer
Publication Date: 2021.05.12 MITSUBISHI ELECTRIC CORP
  • EP3281573B1 patent drawingFigure 1~2
  • EP3281573B1 patent drawingFigure 3~4
  • EP3281573B1 patent drawingFigure 5

AI summary

A hand dryer includes a nozzle (10) for blowing out an airflow toward a drying space (3), which is open at the front and the left and right sides so that hands can be freely inserted and withdrawn, and a water receiving part (4) that receives water droplets blown away from hands inserted in the drying space (3) by the airflow blown out vertically downward from the nozzle (10). While the airflow is being blown out vertically downward from the nozzle (10), the water receiving part (4) and the nozzle (10) do not directly face each other.