Controlled generation of monodisperse aerosols in the submicron range

Abstract

In this paper a new approach is described for the generation of monodisperse ultrafine aerosols. Although numerous research-type aerosol generators have been developed or proposed for generating monodisperse aerosols in the submicron range, there is at present no reliable method available for a controlled generation of ultrafine monodisperse aerosols for a wide spectrum of materials. The proposed method utilizes a transpiration-cooled anode operated in a high intensity arc. In this situation the aerosol is generated continuously by ablation of anode material at the steady arc attachment spot which is the hottest part of the anode surface. The transpiring gas passing through the anode provides quenching of the vapor and immediate dilution of the generated particles in the vicinity of the anode surface, in this way avoiding coagulation and formation of agglomerations. The results show that the aerosol generator described in this paper provides aerosol particles whose mean dia. can be controlled in the range from 45 Å to about 1 μm with a logarithmic S.D. mainly in the range from 1·1 to 1·2; in other words, the transpiration cooled plasma torch particle generator can produce monodisperse aerosols of controlled size anywhere in the submicron range.