Powder disperser for the continuous aerosolizing of dry powdered nanoparticles

A new method has been developed for the continuous aerosolization of dry powdered nanoparticles using a commercially available and cost-effective vacuum generator. A commercial doser was used to supply nanoparticles continuously and precisely. A novel device (called a pressure equilibrium unit) was designed to connect the doser and the vacuum generator to make sure both parts avoid suffering from pressure shock. This system is denoted as a continuous vacuum generator disperser (CVGD). The dosing rate of the CVGD for different particle materials tends to a constant value. All the aerosolized engineered nanoparticles (ENPs) of varying materials and primary diameter obtained through the CVGD distribute identically log-normally as a whole. It is more difficult to separate the nanoparticles of smaller primary diameter using the CVGD, due to the stronger van der Waals attractive force between them. The total particle concentration can be adjusted easily by changing the motor speed of the doser (Dr), which was directly proportional to the dosing rate. As Dr increased, the PSDs shifted to a larger diameter to some extent. For sufficient large dosing rates, the CVGD performance could be improved significantly by increasing the inlet pressure of the vacuum generator (P-j). (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.