Hand Dryer Slot Geometry for High-Momentum Airflow
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Solution Overview
Problem
Existing hand dryers fail to achieve evenly distributed airflow of sufficient high momentum to dry hands efficiently in a short time.
Innovation Solution
The hand dryer design features a casing with slot-like openings, each no wider than 1.0 mm, directing high-velocity, high-pressure air jets transversely across the cavity, with preferred widths of 0.3 to 0.4 mm for enhanced momentum and even airflow distribution, and optionally varying widths to focus air on harder-to-dry areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a wider opening is used to emit airflow, then the device complexity is reduced and ease of manufacture is improved, but the momentum of the airflow is insufficient and drying efficiency deteriorates
Solution Approach 1:
The patent changes the critical parameter of opening width to no more than 1.0 mm (preferably 0.3-0.4 mm) to increase airflow momentum. This parameter change resolves the contradiction by optimizing the opening dimensions to achieve both manufacturability and high drying efficiency through enhanced airflow momentum.
2Productivity
If a narrower slot-like opening is used to increase airflow momentum, then drying efficiency is improved, but the ease of manufacture decreases and manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise opening width parameters (no more than 1.0 mm, preferably 0.3-0.4 mm) to optimize airflow momentum while maintaining manufacturing feasibility. This parameter optimization resolves the contradiction by defining a specific range that balances drying efficiency with manufacturing capabilities.
3Area of stationary object
If the airflow is directed to cover the entire cavity, then the area of coverage is maximized, but the momentum of the airflow is reduced and drying efficiency deteriorates
Solution Approach 1:
The patent employs multiple slot-like openings distributed at different locations (front wall, rear wall, and side walls) with optimized dimensions. This local quality approach ensures that each opening maintains high airflow momentum while the collective arrangement provides comprehensive cavity coverage, resolving the contradiction between coverage area and drying efficiency.
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 significantly increases drying efficiency by blowing more water off the hands per pass with even airflow distribution, allowing for quick and effective hand drying in a single pass.
Implementation Method 1
a narrow jet of high velocity, high pressure air to dry an object
Implementation Method 2
a fan located in the casing and capable of creating an airflow
Implementation Method 3
the momentum of the airflow emitted through the opening is greatly increased... This increases the efficiency of the dryer by virtue of the fact that more water is blown from the object during each pass
Data Source
AI summary
A drying apparatus has a casing, a cavity formed in the casing for receiving an object, a fan located in the casing and creating an airflow, and at least one slot-like opening communicating with the fan and arranged in the casing so as to direct an airflow transversely across the cavity. The slot-like opening has a maximum width which is no greater than 0.8 mm. This produces a very narrow, high velocity, high pressure airflow which is capable of drying an object efficiently and quickly and is suitable for use in a hand dryer.