Hand Dryer Cavity Shape for Uniform Air-Jet Drying

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Solution Overview

Problem

Existing hand dryers often dry hands unevenly, leading to discomfort and inefficiency as users need to dry different parts of their hands sequentially, resulting in longer drying times and reduced user experience.

Innovation Solution

A hand dryer design featuring a casing with a cavity shaped to accommodate hands, equipped with slot-like openings for airflow that ensures uniform distance from the hands to the air jets, with a straight front edge and curved rear edge to match the natural shape of hands, allowing for consistent drying across the entire hand surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the cavity is shaped with curved walls and nozzles positioned accordingly, then the drying coverage is improved, but the distance uniformity between nozzles and hands deteriorates, resulting in uneven drying rates

Engineering Contradiction:
Improvedrying coverageVSAvoiddistance uniformity
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The cavity rear edge is shaped with curved portions that follow the natural contour of human hands, creating a form-fitting cavity entrance. This curvature ensures that when hands are inserted, the distance from any point on the hands to the slot-like openings remains substantially uniform, resolving the contradiction between coverage and distance uniformity

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The slot-like openings are positioned along the rear edge of the cavity entrance where they can uniformly service the entire hand surface. The localized positioning of these openings in relation to the curved cavity shape ensures consistent drying performance across different hand positions and orientations

Inventive Principle:
Principle #3Local quality

2Area of stationary object

If multiple nozzles are positioned at different locations, then the drying coverage is improved, but the drying time increases due to sequential drying of different hand parts

Engineering Contradiction:
Improvedrying coverageVSAvoiddrying time
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The slot-like openings are arranged to provide continuous drying action across the entire hand surface simultaneously. The uniform distance from all hand surfaces to the openings ensures that drying occurs evenly and concurrently across palms, fingers, and backs of hands, eliminating sequential drying delays

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The drying function is segmented into multiple slot-like openings distributed along the rear edge, with each segment contributing to drying a specific region. This segmentation allows parallel drying of different hand areas while maintaining uniform distance for consistent drying rates across all segments

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the cavity entrance is made larger to accommodate hands more easily, then the ease of operation is improved, but the distance uniformity between openings and hands deteriorates

Engineering Contradiction:
Improveease of hand insertionVSAvoiddistance uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The cavity entrance is shaped with curved portions that naturally guide hands into the correct position. This ergonomic shaping facilitates easy insertion while simultaneously ensuring that the hands assume a position where uniform distance to the slot-like openings is maintained, resolving the contradiction between ease of operation and distance precision

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

This design enables even and rapid hand drying, minimizing the time required to dry hands completely and ensuring all areas are effectively dried in a single pass, enhancing user comfort and efficiency.

Implementation Method 1

a fan located in the casing and capable of creating an airflow

Methodology Applied
Scientific EffectAirflow:

Implementation Method 2

narrow streams of high velocity, high pressure air to dry a user's hands

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP1909628B1Hand dryer
Publication Date: 2012.10.10 DYSON TECH LTD
  • EP1909628B1 patent drawingFigure 1~2
  • EP1909628B1 patent drawingFigure 2a
  • EP1909628B1 patent drawingFigure 3

AI summary

Hand drying apparatus (10) has a casing (12), a cavity (30) formed in the casing (12) for receiving for receiving a user's hands, a fan (40) located in the casing (12) and capable of creating an airflow, and a plurality of openings (60, 62) communicating with the fan (40) and arranged to direct an airflow transversely across the cavity (30). The cavity (30) has an entrance (32) delimited by a front edge (32a) and a rear edge (32b) in which the openings (60, 62) are located. The shape of the front and rear edges (32a, 32b) is such that, when in use the user's hands are introduced to the cavity (30), the distance between the user's hands and the nearest opening (60, 62) is substantially uniform. Alternatively, one of the edges (32a) is substantially straight and the other of the said edges (32b) is curved so that the distance between the said edges (32a, 32b) varies along the length of the cavity entrance (32). These arrangements enhance the drying efficiency of the dryer.