Hand Dryer Air-Intake Double-Slit Structure for Noise Reduction
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Solution Overview
Problem
Commercially available hand dryers face a challenge in balancing efficiency and noise reduction, as increasing motor speed to enhance drying efficiency leads to increased wind noise, and existing noise-reduction methods, such as improved blower structures and air path designs, do not achieve 'super-silent' operation.
Innovation Solution
A hand dryer design featuring a housing with a flow-guide plate and air supply module, where the flow-guide plate has narrow air guide holes and is positioned inside the housing without contact with the air intake surface, forming a double-slit structure with the air inlets to reduce noise by canceling sound waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotational speed of the motor is increased to improve drying efficiency, then productivity is improved, but wind noise increases
Solution Approach 1:
The air inlet structure is segmented into multiple narrow air inlets distributed across the housing surface, rather than using a single large inlet. This segmentation allows air to be drawn from multiple locations simultaneously, reducing turbulence and wind noise while maintaining the total air intake volume needed for efficient drying
Solution Approach 2:
The flow-guide plate is positioned at specific locations inside the housing to locally guide air flow patterns. By creating localized flow guidance zones rather than attempting to control the entire air path uniformly, the design reduces turbulence-induced noise while preserving overall air intake efficiency
2Object-generated harmful factors
If the rotational speed of the motor is reduced to reduce wind noise, then noise is reduced, but drying efficiency decreases
Solution Approach 1:
Multiple narrow air inlets are distributed across the housing to segment the air intake process. This allows sufficient air volume to be drawn in at lower motor speeds by utilizing parallel flow paths, maintaining drying efficiency while reducing the rotational speed needed and thereby reducing wind noise
Solution Approach 2:
The flow-guide plate is positioned in three-dimensional space within the housing without contacting the air intake surface, creating a spatial arrangement that guides air flow through additional dimensional pathways. This spatial optimization enables efficient air intake at lower motor speeds by utilizing volumetric flow patterns rather than relying solely on high-speed linear flow
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 double-slit structure effectively reduces air-intake noise by interfering and canceling sound waves, achieving a noise reduction effect while maintaining efficiency in hand drying.
Implementation Method 1
The plurality of narrow air guide holes and the plurality of narrow air inlets form a double-slit structure. When the hand dryer draws in air, the noise of air that enters along the air intake path can be reduced by the plurality of narrow air guide holes and the plurality of narrow air inlets, thereby reducing the noise when air is being drawn in.
Data Source
AI summary
A hand dryer with reduced air-intake noise includes a housing, a flow-guide plate, and an air supply module. The housing includes an accommodating space and a plurality of narrow air inlets. The flow-guide plate is disposed inside the accommodating space, but the flow-guide plate is not contacted with the housing. The flow-guide plate includes a plurality of narrow air guide holes. The air supply module is disposed inside the accommodating space, and includes a blower that extracts air inside the accommodating space to generate a drying air flow after being started and an air-guide piece connected to the blower to receive the drying air flow. An interval between the narrow air inlet and the narrow air guide hole interferes with transmission of a sound wave formed by the air flowing between the narrow air inlet and the narrow air guide hole, so that generated noise can be greatly reduced.