measurable quantity that is a function of drop size, such as settling or inertial velocities, and light scattering. However, according to Root, neither of these has been standardized for aerosol sprays. In addition, the functional relationship with such methods is complex, and analysis of the data is difficult. The spray pattern technique has the Dye technique gives spray pattern that enables advantage of showing the effects of variables involved in aerosol packages. rapid study of aerosol characteristics Differences in valves and buttons have been determined by studying the patA TECHNIQUE for determining aerosol pound vellum paper. The aerosol is terns formed. In addition to variations spray characteristics by using oil and then sprayed onto the paper for a frac- in valves and buttons, it is also possible water soluble dyes has been developed tion of a second in a closed chamber t o show the effect of viscosity in an at G. Barr & Co. in Chicago. With from a fixed distance, usually 6 to 12 aerosol product. A series of spray patthis technique, says M. J. Root, tech- inches. With an alcohol type aerosol terns made with varying viscosities of nical director, it is possible to obtain product, water soluble D u Pont Crystal mineral oil and with the same propela spray pattern which is a function of Violet Powder is used. With an oil lant mixtures shows spray variations droplet size and distribution, coverage product such as an insecticide, Du Pont ranging from very fine to very coarse area, and wetness or liquid spray Oil Red Powder is used. Patterns ob- sprays. High viscosity oils give the volume. tained with the water soluble dye can coarsest sprays.
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RESEARCH
Spray Sizing
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