Vibrating Aperture Plate Nebulizer for Bubble-Controlled Aerosol Flow
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Solution Overview
Problem
Vibrating aperture plate nebulizers tend to ingest air bubbles through the center of the aperture plate, which can form larger bubbles that stagnate and disrupt nebulization, leading to inefficiencies in converting liquid into aerosol.
Innovation Solution
The nebulizer design includes a large throat area over the aperture plate, a gasket with a textured surface and hydrophilic coating, and a piezoelectric vibration generator mounted downstream, along with spring contacts or conductive pins for power transfer, to minimize bubble formation and ensure consistent liquid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a vibrating aperture plate is used for aerosol generation, then aerosol production is achieved, but air bubbles are ingested through the center of the aperture plate causing stagnation and disruption of nebulization
Solution Approach 1:
The patent applies different surface properties to different regions of the aperture plate. The center region has a hydrophobic coating that repels air bubbles, while the peripheral regions maintain their original wettable properties. This local differentiation allows bubbles to be actively repelled from the critical center area where they would otherwise cause stagnation and disrupt aerosol generation, thereby maintaining both high productivity and reliable consistent operation
Solution Approach 2:
The patent changes the surface energy parameter of the aperture plate by applying a hydrophobic coating to the center region. This parameter change transforms the surface from bubble-attracting to bubble-repelling, preventing bubble accumulation and stagnation. The result is improved reliability of nebulization operation while maintaining aerosol generation efficiency
2Ease of operation
If air bubbles form and coalesce on the aperture plate, then larger bubbles are formed, but these bubbles reduce or interrupt nebulization
Solution Approach 1:
The patent applies preliminary anti-action by pre-treating the center of the aperture plate with a hydrophobic coating before operation. This preliminary modification creates a surface that actively repels air bubbles, preventing their formation and coalescence before they can disrupt nebulization. The system operates continuously without interruption to tap bubbles, maintaining both ease of operation and high conversion 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
The design effectively reduces bubble formation and enhances the efficiency and consistency of aerosol generation by preventing bubble stagnation and coalescence, ensuring reliable operation at high frequencies.
Implementation Method 1
an annular piezoelectric vibration generator
Implementation Method 2
a gasket with a textured surface and hydrophilic coating
Data Source
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AI summary
A nebulizer (650) has an aerosol generator (651), a reservoir (652), and an aerosol outlet (653). A piezoelectric vibration generator (656) is on a downstream side of a support washer (655), and power to the piezo is provided by a spring contact assembly (657). The assembly (657) has upstanding electrical terminals (680, 681) for contact with electrical supply conductors. There are spring terminals (670) extending around a rim of the spring contact assembly (657) to engage an exposed underside of the washer (655), and a resilient ridge (671) extending in the upstream direction to engage the underside of the piezo (656), which itself is on the downstream side of the washer (655).