Abstract: A metered dose inhaler for dispensing a fluid medicament as droplets of small mean particle size without the use of pressurized gas or liquefied propellants. A liquid drug is contained in a fluid reservoir, and metered quantities of the drug are successively presented into a reduced cross-section pressure chamber, with non-return valves controlling the flow of liquid through the device. The metered quantity of the drug is then subjected to a sudden and great increase in pressure by releasing a piston into the pressure chamber. The liquid drug is thereby ejected through an atomizing head, to reduce it to a fine atomized spray of small mean particle size, preferably less than approximately 12 micrometers.

Abstract: A nozzle assembly which comprises a nozzle aperture for discharge of a fluid as a spray of droplets, and a conduit in fluid flow communication with the nozzle aperture. The flow of fluid through the conduit is restricted by the minimum effective cross-sectional area of the conduit transverse to the line of flow of fluid through the conduit so that back flow of fluid from the nozzle aperture through the conduit at ambient and operational pressure differentials is substantially prevented. The invention further provides for a method of discharging a fluid as a spray of droplets, and a spray generating device which includes the nozzle assembly of the present invention.

Abstract: A method for discharging a fluid, notably an aqueous medicament solution, as a spray of droplets by causing a fluid to flow through a nozzle aperture so that a secondary flow is induced in at least part of the flow of fluid through the nozzle aperture by a flap or orifice lip located within the bore of the nozzle passage, and/or adjacent an end of the nozzle passage, and/or adjacent the nozzle aperture. Preferably a secondary flow at the nozzle orifice is induced such that at least 10% of the fluid flows at an exit angle of 90.degree. to the overall line of travel of the remainder of the fluid.

Abstract: A process and a discharge valve assembly are provided for regulating the flow of a liquid product from an aerosol container which is pressurized with a permanent gas propellant. The liquid product is conveyed under pressure to a mixing region and the propellant gas is separately conveyed to the mixing region. The mixture is passed through at least one choke restrictor that is located between the mixing region and the discharge nozzle. The mixture expanding downstream of the restrictor forms a foam-like mixture internally of the valve assembly and prior to discharge of the mixture from the exit nozzle.