Thermal Atomisation of Liquid Medicaments via Heated Surface
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Solution Overview
Problem
Existing methods for atomizing liquid medicaments for inhalation fail to consistently produce aerosols with small droplet sizes, narrow droplet size distribution, and low propagation rates, often requiring complex and costly setups or additional gas streams, which can be inefficient and unsuitable for heat-sensitive formulations.
Innovation Solution
A method involving the directional flow of a liquid jet onto a heated contact surface, where a small proportion of the liquid vaporizes spontaneously, generating a high-pressure vapor that atomizes the remaining liquid into small droplets with a broad velocity distribution, achieving the desired aerosol characteristics without the need for additional gas streams or complex nozzle configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a liquid jet is directed onto a conical deflecting surface for atomisation, then droplets with diameter less than 10 μm can be generated, but it is difficult to achieve a defined droplet size and narrow droplet size distribution
Solution Approach 1:
The invention changes the atomisation mechanism from mechanical deflection to thermal vaporisation. By controlling the temperature of the contact surface and the proportion of vaporised liquid (5-50% by volume), the system achieves precise control over droplet size and distribution. The droplet diameter is controlled by adjusting the heating power and liquid flow rate, providing a defined aerosol with narrow size distribution.
Solution Approach 2:
The invention utilizes the phase transition of liquid to vapor as the core atomisation mechanism. A contact surface heated to above the boiling point of the liquid causes partial vaporisation of the incident liquid jet. The resulting high-pressure vapor expands and atomises the remaining liquid into droplets, producing a consistent aerosol with narrow size distribution.
2Productivity
If additional gas streams are used for pneumatic atomisation, then liquid can be converted into aerosol, but the propagation rate increases and the system becomes more complex
Solution Approach 1:
The system uses the liquid's own vaporisation to provide the expansion force needed for atomisation. The partial vaporisation of the liquid jet generates high-pressure vapor that automatically expands and propels the remaining liquid into droplets. This self-generated vapor pressure replaces the need for external gas streams, simplifying the system while maintaining efficient aerosol generation.
3Manufacturing precision
If a heated contact surface is used for atomisation, then small droplets with narrow size distribution are achieved, but heat exposure may affect sensitive formulations
Solution Approach 1:
The invention applies partial vaporisation rather than complete vaporisation. By controlling the heating power so that only 5-50% of the liquid volume vaporises, the system generates sufficient vapor pressure for atomisation while limiting the total heat exposure. The brief contact time and partial vaporisation approach reduce thermal degradation of heat-sensitive formulations.
Solution Approach 2:
The liquid jet rapidly passes over the heated contact surface, minimizing the residence time and heat exposure. The fast-moving liquid jet interacts with the hot surface for a very short duration, just long enough to generate the necessary vapor pressure for atomisation, then quickly transitions into the aerosol phase, reducing thermal damage to sensitive compounds.
4Productivity
If liquid is mixed with gas stream and directed onto deflecting surface, then nebulisation can be achieved, but the system becomes complicated and droplet size varies greatly
Solution Approach 1:
The invention replaces mechanical nebulisation with thermal atomisation through phase transition. The contact surface heated above the boiling point causes spontaneous vaporisation of the liquid, generating high-pressure vapor that uniformly atomises the liquid into consistent droplets. This thermal mechanism provides superior droplet size consistency compared to mechanical deflection methods.
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
This approach allows for simple, effective, and reproducible atomization of medicaments into aerosols with small droplet sizes, narrow size distribution, and low propagation rates, suitable for inhalation, while minimizing heat exposure to sensitive formulations and reducing production costs.
Implementation Method 1
a small proportion of the liquid undergoes a spontaneous transition from the liquid to the gaseous phase
Implementation Method 2
The liquid is directed in the form of a free jet onto a hot contact surface, in particular a warmed or heated deflecting surface
Implementation Method 3
the spontaneous vaporisation of the liquid occurring above a certain temperature, a very high pressure is produced that ejects or dissolves out, as droplets, a specific amount of liquid from the jet
Implementation Method 4
the phase transition from the liquid to the gaseous state leads to a sharp increase in volume, in the case of water by a factor of ca. 1700
Implementation Method 5
When the jet strikes the surface a small proportion of the liquid undergoes a spontaneous transition from the liquid to the gaseous phase
Data Source
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AI summary
A method and a device for the atomisation of a liquid are proposed. A liquid jet is directed onto a hot contact surface, in particular a deflecting surface, so that a part of the liquid is vaporised. The non-vaporised liquid is atomised into small droplets that form an aerosol. A method for the production of such a device is also proposed.