Apparatus for producing finely divided liquid spray

A process for dispensing an aerosol to an individual which comprises placing in said individual's mouth or nose an apparatus for producing a finely divided liquid spray, said apparatus comprising:

• a first chamber for holding a supply of liquid;
• a second chamber;
• first means for conveying liquid from the first chamber to the second chamber;
• second means distinct from the first means for conveying the liquid from the second chamber back to the first chamber;
• means for producing alternately and repetitively a first pressure differential and either a second different opposite pressure differential or pressure balance between said first and second chambers, said first pressure differential causing the flow of liquid from said first chamber to said second chamber and said second pressure differential or pressure balance causing the flow of said liquid from said second chamber back to said first chamber;
• a hollow plenum chamber having a smooth outer surface over at least a portion thereof and so disposed in the flow path of said liquid as it moves from said first chamber to said second chamber and back to said first chamber as to have at least a portion of the liquid impinge upon its outer surface;
• said plenum chamber defining therein at least one through aperture;
• means for supplying gas under pressure to the interior of the plenum chamber to exit through said aperture;
• and
• outlet means for exiting of the finely divided liquid particles from the apparatus.

A method for producing a finely divided liquid spray comprising:

• providing a supply of liquid in a first chamber;
• alternatively and repetitively generating a pressure differential between said first chamber and a second chamber to convey said liquid from said first chamber to said second chamber, and either a second different opposite pressure differential or pressure balance between said first chamber and said second chamber to convey said liquid back to the first chamber to provide flow over a predetermined flow path;
• directing the flow path of at least a portion of said liquid at is flows over its said flow path so as to impinge upon a smooth outer surface of a hollow plenum chamber having at least one aperture therein so that the liquid flows as a thin film over said at least one aperture;
• supplying gas under pressure to the interior of said plenum chamber;
• causing said gas to escape through at least one aperture in said plenum chamber to thereby rupture said film as the liquid flows over said at least one aperture and cause dispersion of finely divided liquid particles;
• and
• permitting said finely divided liquid particles to exit from at least one of said first chamber or said second chamber.