Micro atomizer

Inventors

Horsmon, Michael S. • Crouse, Charles L. • Kreis, Richard J.

Assignees

United States Department of the Army • Government of the United States of America

Abstract

A micro atomizer to produce stable aerosol concentrations having an aerosol mass median aerodynamic diameter (MMAD) of less than 10 microns with liquid flow rates in the microliter per minute range is provided. The micro atomizer includes a liquid channel in the shape of a thick-wall tube and a cap having an aerosol outlet orifice whereby a liquid-gas contact space is formed by the internal surface of the cap and the substantially flat end of the liquid channel. Pressurized carrier gas and the liquid to be aerosolized are allowed to come into contact within a precisely formed liquid-gas contact space. The desired aerosol characteristics are accurately established, stable, and reproducible. In an exemplary embodiment, the micro atomizer is used with a syringe and syringe drive to provide a continuous liquid source for aerosol generation.

Core Innovation

The invention provides a micro atomizer capable of producing stable aerosol concentrations with aerosol mass median aerodynamic diameter (MMAD) of less than 10 microns at liquid flow rates in the microliter per minute range. The micro atomizer comprises a liquid channel formed as a thick-wall tube and a cap with an aerosol outlet orifice, which together form a precisely controlled liquid-gas contact space. Within this space, a pressurized carrier gas and a liquid to be aerosolized come into contact, enabling accurate, stable, and reproducible generation of aerosols.

The problem addressed by the invention arises from limitations of existing aerosol generation devices used especially in inhalation toxicology research. Prior atomizers either require higher liquid flow rates in the milliliter per minute range and high air flow rates unsuitable for small aerosol chambers or produce inconsistent aerosol characteristics due to variable liquid-gas contact spaces. The modified prior art pneumatic atomizer is large and inefficient for ultra-low liquid flow rates, while double-needle atomizers lack reproducibility because small changes in needle positioning cause variation in aerosol properties. There is a need for a micro atomizer that can generate aerosols at low to ultra-low liquid flow rates with precise, consistent, and stable aerosol characteristics.

The micro atomizer invention addresses this need by providing precise positioning of components – specifically, the thick-wall liquid channel with a substantially flat end held along a common centerline within a cap to form a small, controlled clearance gap. This design ensures a reproducible liquid-gas contact space where liquid and pressurized carrier gas interact to produce aerosols. The device can be used with a syringe and syringe drive for continuous and precise liquid feeding, enabling aerosol generation at flow rates of microliters per minute or hour with stable particle sizes and concentrations. This capability fulfills the requirements for inhalation toxicology studies and other applications requiring low-volume, reproducible aerosolization.

Claims Coverage

The patent contains one independent claim outlining the structural and functional features of the micro atomizer.

These features collectively provide a micro atomizer capable of producing stable aerosols with controlled particle sizes at ultralow liquid flow rates by precisely controlling the internal geometry and fluid contact space.

Stated Advantages

Documented Applications