Abstract: A measuring system and process for measuring the size distribution of particles in an aerosol with a time-varying flow utilizing a measuring instrument that utilizes a time-invariant flow rate is provided. The process includes employing a vacuum source to establish a constant flow through the measuring instrument. The vacuum generated by the vacuum source is used to draw an aerosol stream through an inlet incorporating a second stream of relatively particle free gas. The first and/or the second stream may be adjusted so that at any instant of time, the sum of the two streams is a constant value equal to the flow rate through the measuring instrument.

Abstract: A method for automating the process of impaction of particles, recovering samples from a plurality of impaction cups, and washing the cups for a new cycle. The process includes steps of agitating the solvent used for dissolving samples, removing samples and transferring the samples to vials used in an analyzing instrument.

Abstract: A metered dose dispensing valve is described that is particularly suitable for dispensing metered volumes of a pressurised aerosol formulation. The valve comprises a chamber, and a valve stem extending into the chamber and movable relative to the chamber between non-dispensing and dispensing positions.

Abstract: The present invention relates to a low particle loss cascade impactor with particle collection in externally removable cups for determining the size distribution of particles delivered form an aerosol atomizer. A plurality of downwardly facing cavities formed in the body are arranged from a first end to a second end of the body in a generally zig-zag pattern. Each cavity has a generally cylindrical inner wall surface defining an opening facing in a second direction and a surface facing in a first direction. An entrance passage extends from the outer surface of the body at the first end to a center region of a first cavity. The impaction stage is positioned such that a center line of the impaction stage intersects a center bisecting plane passing through the body at an included angle between about 10.degree. to 80.degree..

Abstract: An apparatus for administering a nebulized substance to a subject comprising a nebulizer and a valve assembly which permits continuous and constant flow of pressured gas through the nebulizer even when the apparatus is not being used to administer the substance to a subject. This steady state operation of the nebulizer provides for administration of a controlled dose of the substance. A method for administering a controlled dose to a subject is also described.