Linear-Channel Nebulizer for Monodisperse Droplet Control
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Solution Overview
Problem
Existing nebulizers suffer from inefficiencies in droplet generation, require separate gas sources, generate excessive heat, are costly due to expensive components, and necessitate frequent cleaning or replacement, leading to inconsistent droplet sizes and therapeutic inefficiencies.
Innovation Solution
A nebulizer with a linear channel substrate and piezoelectric actuator that generates high-frequency vibrations, allowing for controlled droplet size through capillary wave formation, using a disposable silicon substrate to minimize heat exposure and eliminate the need for cleaning, and enabling on-demand droplet size adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a jet nebulizer is used to generate aerosol, then aerosol generation speed is improved, but the nebulizer cannot be sterilized by autoclaving due to damage to internal components
Solution Approach 1:
The nebulizer is divided into sterilizable components (chamber, reservoir) and non-sterilizable components (piezoelectric crystal, transducer). The chamber can be detached and autoclaved, while electronic components remain outside the sterilization process. This segmentation allows the device to maintain both high productivity and partial sterilization capability.
Solution Approach 2:
The piezoelectric crystal and transducer are extracted from the sterilization process. These components are mounted on the exterior of the chamber or on a support structure that prevents them from being exposed to autoclaving conditions, while the chamber itself can be fully sterilized.
2Productivity
If ultrasonic vibration is applied to generate aerosol, then aerosol generation efficiency is improved, but liquid is lost through splashing
Solution Approach 1:
The ultrasonic vibration is applied locally at the interface between the liquid and the piezoelectric crystal, rather than to the entire liquid volume. This localized application generates aerosol efficiently at the source while minimizing disturbance to the bulk liquid, thereby reducing splashing and liquid loss.
Solution Approach 2:
The piezoelectric crystal is nested within or in direct contact with the liquid reservoir in a controlled manner. The crystal is positioned such that it vibrates the liquid surface effectively for aerosol generation while being contained within the chamber structure that prevents splashing.
3Device complexity
If a piezoelectric crystal is used for aerosol generation, then device simplicity is improved, but the crystal deteriorates over time
Solution Approach 1:
A damping material is placed between the piezoelectric crystal and the chamber wall to cushion mechanical stresses. This protective layer absorbs shock and reduces stress concentration on the crystal during operation and cleaning processes, thereby extending its service life while maintaining the simple device structure.
4Reliability
If the nebulizer chamber is made sterilizable by autoclaving, then sterilization capability is improved, but electronic components cannot withstand high temperature
Solution Approach 1:
The device is segmented into a sterilizable chamber and non-sterilizable electronic components. The chamber can be detached and autoclaved at high temperatures, while the piezoelectric crystal and transducer remain outside the sterilization chamber or are protected from thermal exposure.
Solution Approach 2:
Electronic components are extracted from the sterilization process entirely. They are mounted on the exterior of the chamber or on a support structure that prevents them from being exposed to autoclaving temperatures, allowing the chamber to be fully sterilized without damaging electronics.
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
Produces highly monodisperse aerosol particles with low variability, reducing thermal impact and operational costs, and enhancing therapeutic efficacy by precise droplet deposition in the lungs.
Implementation Method 1
a vibration generator mounted on an upper surface of the substrate at a position spaced from the channel and comprising a piezoelectric actuator which, when excited, generates high frequency vibrations that transmit through the substrate in a direction towards the channel
Implementation Method 2
allowing for controlled droplet size through capillary wave formation
Implementation Method 3
high frequency vibrations that transmit through the substrate in a direction towards the channel and cause atomisation of fluid within the channel
Data Source
Figure 1~5
Figure 3~4
Figure 6(a)~7
AI summary
A nebulizer (10) comprising a housing which defines, a chamber that has an outlet to the chamber for the egress of atomised fluid particles from within the chamber. The nebulizer (10) further including solid substrate (11) within the chamber of the housing. A linear channel (12) being formed in the substrate (11) that has a closed base, opposite side walls and an opening that opens through an upper surface of the substrate (11). A vibration generator (17) being attached to the substrate (11) at a position spaced from the channel (12) for generating high frequency vibration that transmits through the substrate (11) to the channel (12) to atomise fluid within the channel (12). A feeding facility (15) being provided for feeding fluid to the channel (12).