DEGREASING TECHNOLOGY WITH OZONE MICRO-BUBBLES GENERATED BY A VENTURI TUBE

摘要

As one of the cleaning processes for plating technology, degreasing uses organic solvents and alkali aqueous solutions, though these are costly and have severe environmental impacts because of the sewage disposal. Therefore, cheaper and more eco-friendly degreasing technology is in high demand. Ozone microbubbles, generated using a Venturi tube, have been proposed for degreasing because of their strong oxidizing and self-decomposing power. The purpose of this study is to research the capability of ozone microbubbles and improve the cleaning mechanism. In this study, we focus on microbubble generation using a Venturi tube. The bubble diameters were measured and compared at the inlet and outlet of a straight tube and a Venturi tube. Bubbles were detected by visual observation and measured using image processing software. Compared to the straight tube, the Venturi tube generated much smaller bubbles, whose diameters were approximately 100-120 μm. Through titration with potassium iodide, ozonated water concentrations and ozone gas concentrations were measured under the same conditions. Ozone gas dissolved well through the Venturi tube. Also, brass test plates applied with cutting oil were washed using a flow of ozone microbubbles. It was confirmed that the Venturi tube yielded much better oil-washing capabilities than the straight tube.