Hand Dryer Sensor Delay Control to Reduce Splashback
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Solution Overview
Problem
In integrated lavatory systems, users often fail to slide their hands from the wash basin to the hand dryer's drying zone correctly, leading to splashback of water onto themselves, the floor, or the countertop, due to the existing activation mechanisms not adequately accounting for different hand presentation methods.
Innovation Solution
A hand dryer with multiple proximity sensors that detect the point of entry into the drying zone, implementing a delay before activation based on whether hands are presented from the side or front, with longer delays for front-presentment to ensure hands are fully inserted before air is blown, reducing splashback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single proximity sensor is used to detect hand presence, then the device complexity is reduced, but the ability to differentiate between side-presentment and front-presentment is lost, resulting in splashback
Solution Approach 1:
The detection system is segmented into multiple proximity sensors positioned at different locations (side sensor and front sensor) to detect hand presence from different directions. This segmentation allows the system to distinguish between side-presentment and front-presentment, enabling selective delay activation to prevent splashback while maintaining manageable device complexity.
2Speed
If the hand dryer is activated immediately upon detecting hands, then the drying response time is reduced, but water splashback onto the user, floor, or countertop occurs
Solution Approach 1:
The system performs a preliminary assessment by detecting which sensor is triggered first (side sensor or front sensor) before activating the hand dryer. When the front sensor is triggered first, a delay is introduced to allow the user to fully insert their hands into the drying zone before air flow begins. This preliminary detection and conditional delay prevents splashback while maintaining quick response when appropriate.
3Object-affected harmful factors
If multiple proximity sensors with selective delay are implemented, then splashback is minimized, but the device complexity increases
Solution Approach 1:
The hand dryer activation is made dynamic and adaptive based on real-time sensor input. The system continuously monitors which sensor is triggered first and dynamically adjusts the activation timing accordingly - immediate activation for side-presentment, delayed activation for front-presentment. This dynamic response minimizes splashback while keeping the control system relatively simple through straightforward conditional logic.
4Productivity
If the hand dryer is mounted away from the wash basin, then more wash basins can be served, but water accumulates on the floor creating slippery conditions
Solution Approach 1:
The hand dryer is merged with the wash basin by positioning it directly above the basin. This integration allows the drying zone to overlap with the basin area, enabling users to transition their hands from washing to drying without leaving the wash station. The merged configuration prevents water from being carried to the floor while still allowing multiple wash basins to be served through strategic placement.
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 solution effectively minimizes splashback and ensures efficient drying without water accumulation on the floor or countertop, enhancing user safety and hygiene by ensuring hands are fully inserted before the drying process begins.
Implementation Method 1
A blower delivers a volume of air to the air outlets
Implementation Method 2
Multiple proximity sensors operably connected to the blower turn the blower on and off when triggered by an object, i.e., detection of the user's hand(s)
Data Source
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AI summary
A lavatory system includes a hand dryer with at least a first proximity sensor and a second proximity sensor to detect an object for drying. A controller is communicatively linked to the first and second proximity sensors. The controller activates a drying operation after a first delay period if the first proximity sensor first detects the object for drying and activates a drying operation after a second delay period if the second proximity sensor first detects the object for drying. A filter flow sensor may also be provided to ensure proper filtering of the dryer's air.