A Small Spray Drying Device Design Based On Ultrasonic Nebulizer

With more and more attention in the excellent properties of ultra fine particles and nanoparticles, spray drying device--preparation apparatus of ultra fine particles and nanoparticles is also extremely concerned. Spray dryer have the advantages of high drying speed, simple operation and eliminating the particle agglomeration. However, its disadvantage is the large volume and complex structure of atomizer. This paper presents a small spray drying device based on ultrasonic atomizer, and the innovation of the spray drying device is the ultrasonic atomizer. Because the ultrasonic atomizer serving as the atomizer of spray drying device has the merit of small volume and simple construction. And the circuit system designed for ultrasonic atomizer can eliminate the agglomeration of nanoparticles.Based on the above research purposes, the focus of this paper is the circuit design of small spray drying device and the research of spray characteristics of the ultrasonic atomizer. First, introduces the research status of the spray drying equipment, especially the spray drying device closely related to this paper’s research purpose, and lead to detail research content. Secondly, this paper introduces the structure and the atomization mechanism of the elected ultrasonic atomizer. Then design the whole scheme of the small spray drying device, and introduces the working mechanism and structure of small spray drying device. Experiment on the spray characteristics of the ultrasonic atomizer, and making brief introduction the needed equipments and their mechanism of these experiments. To verify the small spray drying device, which is based on the ultrasonic atomizer, can eliminate the agglomeration of nanoparticles, we have done the feasibility verification experiment. Finally, we design a circuit system of the small spray drying device, mainly including the main control module, drive module and temperature control, display and power supply module.It is found that the droplets produced by the ultrasonic atomizer will not happen second collision to form larger droplets by experiment. And the average diameter of droplets which contains a number of BaTiO3 particles is smaller than the average diameter of droplets of water. It is found that the average diameter of two types of atomization precursor show no obvious decreasing trend when the driving frequency of ultrasonic atomizer is in the range of 135-141 KHz. While it shows in a state of stable fluctuations when driving frequency is in the range of 142-155 KHz. It is also found that average diameter of the droplets increase gradually, with the increase of the driving voltage of ultrasonic atomizer. All of the findings confirmed the spraying mechanism of formatting droplets and its validity. More than that, it confirmed the ultrasonic atomizer used for small spray drying device can effectively eliminate the agglomeration of nanoparticles.