Curved Nozzle Slots for Quieter Fast Hand Drying
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Solution Overview
Problem
Conventional hand dryers face a trade-off between noise reduction and drying time, as reducing air jet velocity to minimize noise leads to increased drying time, and designs like wavy slots are difficult to manufacture and not compact.
Innovation Solution
The hand dryer features curved and scalloped slots in its nozzles that vary in distance and angle of inclination, allowing air jets to intersect at different heights, reducing noise while maintaining effective drying by focusing air flow on hand regions, thus optimizing the intersection point of jets without altering the nozzle profiles significantly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the velocity of the jets is reduced to minimize noise, then noise is reduced, but the drying time increases which is undesirable
Solution Approach 1:
The slot is divided into multiple sections (first scalloped section, second scalloped section, and straight section) with different geometries. Each section generates jets at different velocities and angles, creating localized variations in jet characteristics that collectively reduce noise while maintaining effective drying time
Solution Approach 2:
The single slot is segmented into multiple distinct sections along its length. The first scalloped section, second scalloped section, and straight section each contribute differently to the overall jet pattern, allowing the system to achieve noise reduction without sacrificing drying performance
2Object-affected harmful factors
If wavy slot is used to reduce noise, then noise is reduced, but the design becomes difficult to manufacture and not compact
Solution Approach 1:
Instead of using a complex continuous wavy slot, the design segments the slot into simpler geometric sections (scalloped and straight portions) that are easier to manufacture while achieving similar noise reduction effects through controlled jet intersection
Solution Approach 2:
The scalloped sections introduce controlled curvature to the slot geometry to modify jet patterns and reduce noise, but the curvature is applied in a simplified, periodic manner that is more manufacturable than continuous wavy profiles
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 reduces noise interference while maintaining similar overall drying times by varying the jet intersection point, allowing for simpler and cost-effective manufacturing of the nozzles.
Implementation Method 1
a blower which blows air through the jetting nozzles to produce an air jet
Implementation Method 2
at least a portion of each of the first and second slots is curved such that the distance between the slots varies in the longitudinal direction... the collision of the jets contributes to the noise produced by the hand dryer
Data Source
AI summary
A hand dryer comprising a first jetting nozzle comprising a first duct in fluid communication with a first slot which forms a first nozzle outlet and a second jetting nozzle, disposed opposite the first jetting nozzle, comprising a second duct in fluid communication with a second slot which forms a second nozzle outlet. The first and second slots extend transversely with respect to the hand dryer. At least a portion of each of the first and second slots is curved such that the distance between the slots varies in the longitudinal direction of at least one of the slots. The hand dryer further comprises a blower which blows air through the jetting nozzles to produce respective air jets.