An aerosol generator includes a flow passage having an inlet end, an outlet end, and a constriction in the flow passage at the outlet end. A heater is operable to heat liquid in the flow passage to produce a vapor, which is expelled from the outlet end of the flow passage....http://www.google.de/patents/US7500479?utm_source=gb-gplus-sharePatent US7500479 - Aerosol generators and methods for producing aerosols
