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Atomization and Sprays

Journal of the International Institutes for Liquid Atomization and Spray Systems

ISSN for PRINT: 1045-5110

Institutional price:	$787.00
Issues per year:	8

Best Paper Award Selection - Editorial Board Site

2005, Volume15

130 pages

Issue price - $92.00

SUPPRESSION OF AEROSOL GENERATION DURING SPRAYING AND DEPOSITION OF CONSUMER PRODUCTS

D. Ken Giles
Department of Biological and Agricultural Engineering, University of California—Davis, Bainer Hall, One Shields Avenue, Davis, CA 95616, USA

D. Downey
Department of Biological and Agricultural Engineering, University of California—Davis, Bainer Hall, One Shields Avenue, Davis, CA 95616

H. Scher
Department of Biological and Agricultural Engineering, University of California—Davis, Bainer Hall, One Shields Avenue, Davis, CA 95616

D. Winetzky
Genencor International, Palo Alto, CA 94304

T. Becker
Genencor International, Palo Alto, CA 94304

J. Hogue
Genencor International, Palo Alto, CA 94304

ABSTRACT

This study investigated droplet-size spectra and aerosol production from consumer products dispensed by disposable trigger sprayers for deposition on household surfaces. A strategy was devised to reduce the generation of small, mobile droplets through nozzle selection and manipulation of fluid properties. Parametric experiments with a generic laundry stain remover ("prespotter"), five spray dispenser designs, and four concentrations of a long-chain polymer were conducted. Surface tension of the test formulations ranged from 0.0350 to 0.0365 N/m. Shear viscosities ranged from 258 to 165 cps (shear rate of 7.5 s⁻¹) and 66 to 48 cps (shear rate of 75 s⁻¹). Polymer concentrations ranged from 0.00% to 0.10% w/w. Elongational viscosity characteristics were measured using a modified flow technique modeled after R. W. Dexter [14]. Droplet size spectra of the spray discharged from dispensers were measured with a laser-diffraction system. Design of the trigger spray nozzle significantly affected the droplet size spectra. For all trigger sprayers studied, addition of polymer to the spray formulation significantly reduced the generation of aerosol droplets. Mass transfer studies confirmed that addition of polymer reduced airborne spray aerosols by 86% to 94%. Similarly, addition of the polymer reduced the generation of mobile aerosols from spray impaction on target surfaces by 47−98%, depending on nozzle design and target surface characteristics.