Apparatus and method for generating particle aerosols with heliox
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Publication Number
US-10688257-B2
Publication Date
2020-06-23
Expiration Date
Abstract
A system and a method for generating a respirable dry powder aerosol (15) from a liquid solution or liquid suspension at a respirable dry powder aerosol volume flow (91). A liquid aerosol generating nozzle (3) generates from the liquid solution or liquid suspension a liquid aerosol (13) that is diluted by dilution gas (4) and dried in a cylindrical evaporation chamber (6) to generate a dry powder aerosol (14) that is subsequently concentrated. The system and method may include heliox as a gas, specifically dilution gas (4), for enhancing both the drying process in the cylindrical evaporation chamber (6) and for enhancing the concentration efficiency, but also as a nozzle gas (2) for enhancing generating the liquid aerosol (13) from the liquid solution or liquid suspension.
Core Innovation
The invention relates to an aerosol generating system for generating a respirable dry powder aerosol from a liquid solution or liquid suspension. The system includes a liquid aerosol generating nozzle configured to output a liquid aerosol suspended in a first heliox volume flow, and the nozzle output is supplied to a cylindrical evaporation chamber that receives a second heliox volume flow that dilutes the liquid aerosol in the chamber. The cylindrical evaporation chamber outputs a first intermediate dry powder aerosol at a first intermediate dry powder aerosol volume flow and a first intermediate dry powder aerosol particle concentration.
At least one concentrator is coupled to the cylindrical evaporation chamber output end to convert the first intermediate dry powder aerosol into a respirable dry powder aerosol. In one option, the concentrator comprises a cylindrical single linear slit aerosol concentrator having a converging cylindrical single linear slit aerosol concentrator input channel, a cylindrical single linear slit aerosol concentrator input orifice connected to a cylindrical single linear slit aerosol concentrator aerosol separation space, and a cylindrical single linear slit aerosol concentrator output orifice connected to a cylindrical single linear slit aerosol concentrator output channel.
In another option, the concentrator comprises a cylindrical radial multi-slit aerosol concentrator having a plurality of slits extending from a position at or close to a center of the concentrator to a position more remote from the center. The concentrator output outputs the respirable dry powder aerosol at a respirable dry powder aerosol volume flow that is lower than the first intermediate dry powder aerosol volume flow and at a respirable dry powder aerosol particle concentration that is higher than the first intermediate dry powder aerosol particle concentration. Heliox is presented as improving atomization, drying, and concentration efficiency while enabling fine particles with respirable particle characteristics.
Claims Coverage
Two independent claims are present, directed respectively to an aerosol generating system and a method. The inventive coverage centers on heliox-driven nozzle atomization and heliox-diluted cylindrical evaporation to form a first intermediate dry powder aerosol, followed by concentration using cylindrical slit concentrators that produce lower volume flow and higher particle concentration for the respirable dry powder aerosol.
Heliox liquid aerosol generating nozzle with first heliox supply
A liquid aerosol generating nozzle receives the liquid solution or liquid suspension, a first heliox supply receives a first heliox volume flow, and the nozzle outputs a liquid aerosol suspended in the first heliox volume flow.
Cylindrical evaporation chamber with second heliox dilution to form intermediate dry powder aerosol
A cylindrical evaporation chamber receives the liquid aerosol suspended in the first heliox volume flow and a second heliox volume flow that dilutes the liquid aerosol, and outputs a first intermediate dry powder aerosol at a first intermediate dry powder aerosol volume flow and a first intermediate dry powder aerosol particle concentration.
Cylindrical single linear slit aerosol concentrator for virtual impaction concentration
A cylindrical single linear slit aerosol concentrator receives the first intermediate dry powder aerosol and includes a converging input channel, an input orifice connected to an aerosol separation space, and an output orifice connected to an output channel, with the output providing lower volume flow and higher particle concentration than the intermediate.
Cylindrical radial multi-slit aerosol concentrator for virtual impaction concentration
A cylindrical radial multi-slit aerosol concentrator includes a plurality of slits extending from at or close to a center to positions more remote from the center, and outputs the respirable dry powder aerosol at a volume flow lower than the first intermediate dry powder aerosol volume flow and a particle concentration higher than the first intermediate dry powder aerosol particle concentration.
Heliox method for producing intermediate dry powder aerosol and concentrator output
A method feeds liquid solution or liquid suspension and a first heliox volume flow into a liquid aerosol generating nozzle, outputs a liquid aerosol suspended in the first heliox volume flow into a cylindrical evaporation chamber, feeds a second heliox volume flow into the chamber to dilute the liquid aerosol, outputs a first intermediate dry powder aerosol, feeds the first intermediate dry powder aerosol into at least one cylindrical radial multi-slit aerosol concentrator or cylindrical single linear slit aerosol concentrator, and outputs a respirable dry powder aerosol at lower volume flow and higher particle concentration than the intermediate.
Across system and method claims, the core coverage is the sequence of heliox-assisted liquid aerosol generation into a cylindrical evaporation chamber to create a first intermediate dry powder aerosol, followed by concentration using cylindrical single linear slit and/or cylindrical radial multi-slit concentrator structures that output a respirable dry powder aerosol with lower volume flow and higher particle concentration than the intermediate.
Stated Advantages
Enables the generation of respirable fine particles at high payload/throughput.
Improves atomization using heliox via higher Weber number.
Improves drying using heliox via higher specific heat, thermal conductivity, and diffusion.
Improves concentration efficiency for producing respirable dry powder aerosol with increased particle concentration and reduced volume flow.
Heliox enables fine particle generation with stated performance metrics including concentration efficiency up to about 86% and particle concentration/delivery improvements.
Documented Applications
Aerosol generation for producing a respirable dry powder aerosol including particles containing a medically active agent.
Surfactant replacement therapy.
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