Silicon Ultrasonic Nozzle Without Central Channel
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Solution Overview
Problem
Existing ultrasonic nozzle devices are unable to produce monodisperse or narrowly-sized droplets in the 1 to 6 μm size range at high throughput and low electrical drive power, and require complex fabrication processes due to the need for a central channel for liquid transport.
Innovation Solution
The use of miniaturized silicon-based ultrasonic nozzle devices with multiple Fourier horns that activate a pure capillary wave atomization mechanism, eliminating the need for a central channel and utilizing external liquid transport methods to achieve high-throughput production of monodisperse or narrowly-sized micrometer- and sub-micrometer-sized droplets at reduced electrical drive power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a central channel is used to transport liquid to the nozzle tip, then liquid transport is achieved, but device complexity and fabrication difficulty increase
Solution Approach 1:
The patent removes the central channel structure from the nozzle device, extracting the liquid transport function from the nozzle body itself and implementing it through external liquid delivery systems. This eliminates the complex internal channel fabrication while maintaining effective liquid transport to the atomization surface.
Solution Approach 2:
The patent introduces external liquid delivery components (such as separate liquid supply channels or capillaries) that act as intermediaries between the liquid source and the atomization surface. These external delivery mechanisms replace the need for integrated central channels within the nozzle body.
2Manufacturing precision
If operating frequency is increased to produce smaller droplets, then droplet size decreases, but device physical size decreases and channel fabrication complexity increases
Solution Approach 1:
By removing the central channel structure entirely, the patent eliminates the fabrication complexity that would otherwise increase with higher operating frequencies and smaller device dimensions. The liquid transport function is achieved through external delivery rather than internal channels.
3Manufacturing precision
If central channel cross section is reduced to match smaller nozzle size, then droplet size decreases, but liquid flow rate and throughput decrease
Solution Approach 1:
The patent moves the liquid transport path from a three-dimensional internal channel within the nozzle body to external delivery structures. This allows the atomization surface area to be optimized for droplet size while the liquid supply can be independently configured through external channels, maintaining high throughput.
Solution Approach 2:
The patent separates the liquid delivery function from the atomization function by using external liquid supply components. This segmentation allows independent optimization of the atomization surface for droplet size control while the external liquid delivery maintains adequate flow rates without being constrained by the nozzle body dimensions.
4Productivity
If conventional ultrasonic nozzles are used, then droplet ejection is achieved, but electrical drive power requirements exceed 10 W
Solution Approach 1:
The patent changes the operating parameters by using higher frequency vibration (ultrasonic range) and optimizing the liquid delivery parameters through external channels. This allows the system to achieve effective droplet ejection at lower electrical drive power levels compared to conventional nozzles operating at lower frequencies.
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 enables the production of monodisperse droplets with narrow size distributions and high throughput, reducing manufacturing costs and power consumption, while facilitating applications such as pulmonary drug delivery and micro-electronics coating.
Implementation Method 1
multiple Fourier horns in resonance which activates a pure capillary wave atomization mechanism
Implementation Method 2
miniaturized silicon-based ultrasonic nozzle devices with multiple Fourier horns that operate at megahertz drive frequencies
Implementation Method 3
Piezoelectrically actuated flextensional micromachined ultrasonic transducers with annular piezoelectric disk
Data Source
AI summary
Ultrasonic nozzle devices without a central channel but employing a design of cascaded multiple Fourier horns in resonance produce micrometer-sized monodisperse or narrowly-sized droplets with greatly reduced electrical drive power requirements. The liquid to be atomized is brought externally to or adjacent to the endface of the nozzle tip. The above liquid transport method is equally applicable to the ultrasonic nozzle-array devices that are made up of a plurality of ultrasonic single-nozzle devices configured in parallel. The longitudinal length, transverse width, shape, and area of the nozzle endface of single-nozzle and nozzle-array devices may be tailored or designed (e.g. enlarged) to obtain optimum or large quantities of product droplets to achieve high throughput. By increasing the drive frequency to 8 MHz or higher, sub-micrometer-sized monodisperse or narrowly-sized droplets can be produced using the ultrasonic single-nozzle and nozzle-array devices or any solid endface.