Atomizer Mesh With Hydrophilic-Hydrophobic Coatings for Fine Droplet Generation

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Solution Overview

Problem

Current atomizers are unable to produce droplets with diameters below 3 µm, especially when the viscosity of the liquid is higher than water, limiting their effectiveness for improved nicotine delivery and other applications.

Innovation Solution

A mechanical atomizer with a passive mesh and a vibrating element, where the mesh is coated with hydrophilic and hydrophobic materials, and the nozzles are designed to produce droplets with a mass median aerodynamic diameter (MMAD) between 0.1 µm and 3 µm, allowing for efficient aerosol generation with liquids of varying viscosities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the nozzle diameter is reduced below 3 µm, then the droplet size may be reduced, but the liquid flow through the nozzle becomes restricted especially for high viscosity liquids

Engineering Contradiction:
Improvedroplet diameterVSAvoidliquid flow
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent applies different surface properties at different locations within the nozzle structure. The inner surface is made hydrophilic to reduce surface tension and facilitate liquid flow, while the outer surface is made hydrophobic to prevent external contamination and maintain droplet integrity. This local differentiation of surface properties allows the nozzle to maintain small dimensions while still accommodating high viscosity liquids effectively.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the liquid viscosity is higher than water (e.g., 10 times higher), then the droplet formation becomes difficult, but reducing the nozzle diameter does not necessarily achieve the desired droplet diameter

Engineering Contradiction:
Improveliquid viscosity rangeVSAvoiddroplet diameter
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent changes the surface energy parameters of the nozzle by applying hydrophilic coating to the inner surface and hydrophobic coating to the outer surface. This parameter change in surface properties reduces the effective surface tension for high viscosity liquids, enabling them to flow through small nozzles and form consistent droplets of the desired diameter despite their high viscosity.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the mesh is made passive (not actuated to vibrate), then the device complexity is reduced, but the droplet size control becomes more challenging

Engineering Contradiction:
Improvemesh actuation systemVSAvoiddroplet diameter
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical vibration system with a surface chemistry-based solution. Instead of using a vibrating mesh to control droplet formation, the invention uses hydrophilic-hydrophobic surface coatings on a passive mesh to control liquid flow and droplet ejection. This substitution eliminates the need for complex actuation mechanisms while maintaining precise droplet size control through surface property management.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 droplets with diameters as low as 0.1 µm to 2.8 µm, accommodating a wider range of liquid viscosities and flavors, enhancing nicotine delivery and aerosol generation efficiency.

Implementation Method 1

The first surface is at least partially coated with a hydrophilic coating or the second surface is at least partially coated with a hydrophobic coating

Methodology Applied
Scientific EffectHydrophilic coating effect: Hydrophile

Implementation Method 2

The first surface is at least partially coated with a hydrophilic coating or the second surface is at least partially coated with a hydrophobic coating

Methodology Applied
Scientific EffectHydrophobic coating effect: Hydrophobe

Implementation Method 3

The vibrating element is actuated by the vibrator system, so that the vibrating element vibrates in a direction substantially transversal to the plane defined by the vibrating element. The liquid from the liquid chamber is in contact with both the vibrating element and the mesh. The vibrations of the vibrating element push periodically upon the liquid, which causes the liquid to move towards and away from the mesh.

Methodology Applied
Scientific EffectMechanical vibration: Vibration

Data Source

PatentEP3793745B1Atomizer and a mesh therefor
Publication Date: 2022.07.06 PHILIP MORRIS PRODUCTS SA
  • EP3793745B1 patent drawingFigure 1a~3
  • EP3793745B1 patent drawingFigure 4

AI summary

A mesh (1) for an atomizer assembly (50) which has a first surface (3) and a second surface (4), and a plurality of nozzles (2) extending between the first surface (3) and the second surface (4). The first surface (3) is at least partially coated with a hydrophilic coating or the second surface (4) is at least partially coated with a hydrophobic coating. The nozzles (2) define an inner surface (5) and wherein the inner surface (5) is at least partially coated with a hydrophilic coating.