Production of Oxygen Ultrafine Bubble Water with Spray Injection from a Pressurized Container

Abstract

A novel ultrafine bubble generation method has been developed in this study. Water with adjusted dissolved oxygen concentration in a pressure vessel was pressurized with oxygen. After sufficient shaking, the water in the pressure vessel was sprayed through the nozzle into the receiver. The formation of ultrafine bubbles was observed in the discharged water, and its number concentration changed depending on the initial dissolved oxygen concentration in the water. The discharged water was returned to the pressure vessel again, pressurized and shaken with oxygen. A series of the operations for spray discharge were repeated many times. The number concentration of ultrafine bubbles generated with the number of repetitions increased. We succeeded in obtaining a number density higher than the number concentration of ultrafine bubbles obtained by repeatedly applying and reducing pressure without spraying. In addition, when the pressurizing pressure was 0.5 MPa the maximum number concentration of ultrafine bubbles was obtained. Therefore, generation of ultrafine bubbles was promoted not only by repeated pressurization and depressurization, but also by spraying from a pressure vessel to a receiver.